T2Cre+ER transgene, we conditionally deleted Gimap1 in C57BL/6 mice and demonstrate that GIMAP1 is intrinsically required for the survival of mature T cells in the periphery. We show that, in contrast to GIMAP5, this requirement is independent of the T‐cells' activation status. We investigated the nature of the survival defect in GIMAP1‐deficient CD4+ T cells and show that the death occurring after GIMAP1 ablation is accompanied by mitochondrial depolarization and activation of the extrinsic apoptotic pathway. This study shows that GIMAP1 is critical for maintaining the peripheral T‐cell pool in mice and offers a potent target for the treatment of T‐cell‐mediated diseases.An effective immune system depends upon the survival of mature T cells in the periphery. Members of the GIMAP family of GTPases have been proposed to regulate this homeostasis, supported by the paucity of peripheral T cells in rodents deficient for either GIMAP1 or GIMAP5. It is unclear whether this lack of T cells is a consequence of an ontological defect, causing the thymus to generate and export T cells incapable of surviving in the periphery, or whether  mature T cells intrinsically require GIMAP1 for survival. Using the  These cells are continuously produced by the thymus from where they egress into the periphery as naive T cells with lifespans ranging from 3 to 10 months in mice GTPases of the IMmunityAssociated Proteins) are a family of 7–9 small GTPases highly expressed in lymphocytes Arabidopsis thaliana, where it is thought to play a role in defence against pathogens Gimap3 in fetal thymic organ culture (FTOC) leads to a block in positive selection during thymopoiesis, while reconstitution experiments using GIMAP3‐deficient bone marrow also demonstrate defective T‐cell development and loss of the mature T‐cell populations Gimap3 and Gimap5 produces a more severe phenotype than either individual deficiency The GIMAPs , to otherwise normal cells. This allows selective ablation of GIMAP1 in mature T cells enabling us to determine if GIMAP1 is intrinsically required for their survival in the periphery.The GIMAP1 protein is consistently expressed at all stages of thymopoiesis and its expression is maintained at a high level in mature lymphocytes + T lymphocytes and of CD4+ and CD8+ T cells in vivo. We show that GIMAP1 is essential for the survival of both resting and activated CD4+ T cells. Closer examination revealed that the cell death observed in GIMAP1‐deficient CD4+ T cells was preceded by loss of mitochondrial function and activation of the extrinsic apoptotic pathway.In the present study we show that loss of GIMAP1 significantly compromises the survival of ex vivo‐cultured mature CD4Gimap1 in early lymphoid progenitors resulted in a profound deficiency in peripheral T and B lymphocytes f/fCD2Cre+Gimap1 animals is due to (A) a requirement for GIMAP1 during development in primary lymphoid organs which impacts on their subsequent ability to survive in the periphery (a “legacy effect”), or (B) a requirement for continuous expression of GIMAP1 in peripheral T cells. To distinguish between these two possibilities, we developed a model in which Gimap1 could be deleted in T cells once they had matured and entered the periphery. f/fGimap1 and T2Cre+ER mice were crossed to generate f/fERT2Cre+Gimap1 mice, with which we could perform conditional ablation of Gimap1with either tamoxifen or its derivative, 4‐OHT. To control for off‐target effects and Cre‐mediated toxicity, all experiments included cells from the T2Cre+ER mouse strain as a control + T cells required GIMAP1. CD4+ T cells were purified from f/fERT2Cre+Gimap1 and T2Cre+ER spleen and lymph nodes and cultured in vitro in IL‐7 for 7–10 days in the presence of either vehicle (DMSO) or 4‐OHT. DNA was purified from cells to assess deletion of Gimap1 and cell lysates were analysed for GIMAP1 protein expression by western blot. As shown in Fig. Gimap1 was deleted by day 2 of culture. However, western blots showed that GIMAP1 protein was detectable until day 6–7 of culture and was completely lost by day 9  stimulation, a stage where cells are undergoing rapid proliferation. f/fERT2Cre+Gimap1 and T2Cre+ERCD4+ T cells were first cultured for 5 days in IL‐7 in the presence of either 4‐OHT or vehicle and were then activated via CD3 and CD28 in the presence of exogenous IL‐2. This design enabled T cells to be activated whilst they still expressed GIMAP1 since GIMAP1 protein was detectable at the point of activation but absent by day 5 of activation  cells and the kinetics of their appearance. As shown in Fig. f/fERT2Cre+Gimap1 T‐cell cultures. Apoptosis is the result of a cascade of signals emanating from the initiator caspases, caspase‐8 and caspase‐9, which are themselves activated by distinct stimuli L, Mcl‐1, Bim, and Bax) in GIMAP1‐deficient cells at early time points . We did find a significant increase in the percentage of cells expressing activated caspase‐8 in GIMAP1‐deficient cells . However, neither inhibitor reversed the cell death (defined by lack of DAPI staining and cell enumeration on day 9 of culture) seen in 4‐OHT‐treated f/fERT2Cre+Gimap1 T cells  by day 7. This was verified by measuring the oxygen consumption rate (OCR) in these cells on day 7 of culture  and cells expressing active casapse 8 , respectively, and then co‐transferred into recipient animals. The recipients were administered tamoxifen on two consecutive days and their spleens harvested 13 days following the adoptive transfer. Splenocytes were stained for CD4, CD8, and CD45.2, and the percentage of donor cells from each strain determined for each recipient animal. As shown in Fig. f/fERT2Cre+Gimap1CD4+ and CD8+ T cells but had little effect on T2Cre+ER T cells. These results show that CD4+and CD8+ T cells require continuous intrinsic GIMAP1 expression for their maintenance within the periphery.To determine if GIMAP1 is also required continuously for T‐cell survival in vivo, we adoptively transferred mature, peripheral CD4Gimap gene expression is silenced or lost in anaplastic T‐cell lymphomas Gimap5 is associated with IA‐2 autoantibody formation in patients with type I diabetes and predisposes individuals to systemic lupus erythematosus The critical importance of the GIMAP family GTPases in the functioning of the immune system is reflected in their association with human diseases. Gimap1 from lymphocytes and found a striking similarity in the lymphopenia observed in our Gimap1‐deficient T cells with that seen in the BioBreeding rat strain Gimap1, although born in normal numbers, rarely survive more than 10 days postnatally (not shown). A further disadvantage to this method of gene ablation is that it potentially confounds the cell‐intrinsic effects of the knock‐out with cell‐extrinsic phenotypes. Our strategy of developing f/fGimap1 mice has enabled us to examine the cell‐intrinsic effects of the Gimap1 lesion by controlling where and when the gene is ablated. For the present study, we have generated a tamoxifen‐inducible Gimap1knockout model that allows temporal control of gene ablation. A unique advantage gained from using the f/fERT2CreGimap1 model is that it allowed us to assay protein turnover and the proficiency of gene ablation. By culturing f/fERT2CreGimap1 CD4+ T cells in vitro, we found that a low dose of 4‐OHT was sufficient to ablate the floxed Gimap1 DNA fragment rapidly and completely. Surprisingly, GIMAP1 protein turnover took 6–7 days. In this system, loss of GIMAP1 resulted in cell death. We confirmed this finding in vivo by adoptively transferring f/fERT2CreGimap1 or T2CreER lymphocytes into congenic recipient animals and administering tamoxifen. This allowed us to monitor the effect of GIMAP1 deletion on CD4+ and CD8+ T cells and extended our finding that GIMAP1 maintains the survival of CD4+ T cells in vitro. The loss of GIMAP1 similarly compromised the survival of f/fERT2CreGimap1 CD8+ T cells, both in vivo and in vitro. Thus, mature T cells require continuous GIMAP1 protein expression for their survival. By ablating GIMAP1 protein during the expansion phase of T‐cell activation we also showed that GIMAP1 is critical for the survival of activated T cells. Previous work with GIMAP5‐deficient T cells had shown that antigenic stimulation could rescue GIMAP5‐deficient T cells from death f/fCD2Cre+Gimap1 strain of mice and suggests that, despite their structural similarities, GIMAP1 and GIMAP5 perform discrete functions in T cells. In recent work we have looked at the effect of GIMAP1 deletion in B cells and also find that both resting and activated B cells depend on GIMAP1 for their survival f/fCD2CreGimap1 animals and again suggests that GIMAP1 and GIMAP5 have different specific roles in regulating lymphocyte survival.The majority of work in the GIMAP field has focused on GIMAP5 + T lymphocytes initially suggested that these cells were dying by apoptosis. However, the apoptotic pathway by which cells were dying was unclear. The reduction of GIMAP1 protein in cultured CD4+ T cells led to mitochondrial depolarization followed by caspase‐8 activation, which suggested that both the intrinsic and extrinsic apoptotic pathways were engaged L, Bax, Bak, Bad and Bim Gimap1 lesion did not appear to affect expression of members of this family in CD4+ T cells and we saw no activation of caspase‐9. Apoptosis in GIMAP5‐deficient T cells is also not prevented by caspase‐9 inhibitors but is prevented by inhibitors for caspase‐3 and caspase‐8 Elevated levels of phosphatidylserine exposure and caspase‐3 activity in GIMAP1‐deficient CD4+and CD8+ T cells remaining in f/fCD2Cre+Gimap1 mice demonstrated elevated levels of activated caspase‐8 and annexin V, confirming our in vitro findings. The extrinsic apoptotic pathway is triggered by healthy cells instructing damaged or infected cells to die and may also be a back‐up mechanism for cells that have escaped deletion by the intrinsic pathway In agreement with this finding, the few CD4f/fCD2Cre+Gimap1 mice have around 30% of mature SP thymocytes, they have <5% of peripheral CD4+ T cells + T cells. Recent work has suggested that loss of mitochondrial electron chain transport function has a greater effect on peripheral T cells than on thymocytes + T cells being more affected than CD4+ T cells Another puzzling feature of the GIMAP1‐deficiency phenotype has been why the T cells mainly succumb to death in the periphery. GIMAP1 is highly expressed during all stages of T‐cell development in the thymus yet only the most mature SP thymocytes show a survival defect f/fGimap1 mice  and CTV (Life Technologies), respectively, and then mixed in a 1:2 ratio (f/fERT2Cre+:ERT2Cre+Gimap1) prior to i.v. injection of 5 × 106 cells/mouse into B6.SJL‐Ptprca Pepcb/BoyJ mice. Mice were treated with 200 μg tamoxifen/g bodyweight in sunflower oil, or vehicle control, i.p. or s.c. on days 1 and 2 following adoptive cell transfer. On day 13 after cell transfer, mice were killed and the numbers of transferred cells present in peripheral blood and spleen were determined.In adoptive‐transfer experiments, lymph node cells from f/fGimap1 allele and deletion of Gimap1 were determined by PCR as previously described The presence of the + lymphocytes were purified from spleens and lymph nodes of f/fERT2CreGimap1+and T2CreER+mice by negative selection. In brief, erythrocytes were lysed prior to incubation of cells with biotinylated anti‐CD19, anti‐IgD, anti‐CD8, anti‐CD25, anti‐NK1.1, anti‐γδTCR, anti‐Gr1, and anti‐CD11b. Cells were washed and then incubated with anti‐biotin MACS beads prior to depletion of bead‐coated cells by AutoMACS (MiltenyiBiotec). Cells were then cultured at 1–2 × 106 cells/ml in 10% FCS IMDM (culture medium) with 5 ng/mL IL‐7 (Peprotech) with vehicle (DMSO) or 50 nM 4‐OHT. After 48 h, cells were washed and resuspended at 1–2 × 106 cells/mL in culture medium with 5ng/mL IL‐7 for a further 2–5 days. Q‐VD‐OPh hydrate  and Z‐Ile‐Glu(O‐ME)‐Thr‐Asp(O‐Me) fluoromethyl ketone  were added to give final concentrations of 10 μg/mL and 100 μg/mL, respectively, on days 6 and 8 of culture. To determine proliferation, cells were first stained with CFSE according to the manufacturer's instructions. Cells were then cultured at a concentration of 1–2 × 106 cells/mL, in anti‐CD3 (eBioscience)‐coated 24‐ or 96‐well plates with anti‐CD28  plus IL‐2  for 24–120 h prior to analysis by flow cytometry. To determine oxygen consumption rate, a Seahorse Extracellular Flux (XF) 24 Analyser (Seahorse Bioscience) was used, as previously described CD4® cell counter and analyzer system (Roche Innovatis AG) or Flow Count beads (Sigma) during flow cytometric analysis. Flow cytometry was performed using a BD LSRII or Fortessa cell analyser (BD), and data were analyzed using Flowjo analytic software.Single cell suspensions then stained with fluorochrome‐conjugated anti‐CD4, anti‐CD8 and anti‐CD25 mAbs (BD Biosciences and eBioscience). For detection of activated caspases, CaspGLOW Fluorescein Active Caspase‐3, Caspase‐8 or Caspase‐9 kits (Biovision) were used according to the manufacturer's instructions. Cells were stained for annexin V and DAPI by incubating with annexin V conjugates (BD Biosciences) and DAPI (Sigma) in annexin V binding buffer (BD Biosciences). To determine mitochondrial health, cells were incubated with JC‐1 (Molecular Probes) for 30 min at 37°C prior to analysis. Cells were counted using either a CASYThe authors declare no financial or commercial conflict of interest.As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re‐organized for online delivery, but are not copy‐edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors.Supplementary Figure 1.Click here for additional data file.Supplementary Figure 2.Click here for additional data file.


Coinfection of hepatitis B virus (HBV) with hepatitis D virus (HDV) has being reported to increase severity of progression to hepatocellular carcinoma (HCC) and liver cirrhosis (LC). Beta microglobulin (2βM) which is present on the surfaces of blood cells in acceptable levels is a tumor marker which may become elevated in disease conditions. This study hence observed the prevalence of HBV and HDV coinfection in a rural population and their 2βM concentration.Of the 368 samples, 66 (17.9%) were positive to hepatitis B surface antigen (HBsAg) and 33 (50%) were coinfected with HDV, 8 (2.1%) were monoinfected with HDV. 2βM concentration increased beyond the normal level in individuals coinfected with HBV and HDV as compared with the monoinfected individuals. Coinfection resulted in the increased concentration of 2βM in HBV and HDV coinfection and the likelihood of progression to HCC and LC may not be ruled out. Monoinfection with HDV also had high 2βM concentration but this is due to having being infected with a non-detected HBV or chronic infection in which HBV is clearing. Hepatitis B virus (HBV) is known to infect approximately 350 million people  who are HBV is a DNA virus in the family Hepadna viridae, it is highly transmissible so that even a very small quantity of blood is enough to transmit the virus. Major routes of entry of the virus include wounds, abrasions, mucous membranes, bites and scratching . The virHepatitis D virus (HDV) is a defective RNA virus which occurs only in HBsAg positive individuals –15 as itIn Nigeria information regarding HDV is scanty but a few have reported HDV in chronic liver diseases . Due to Beta-2-microglobulin is one of the major histocompatibility complex class molecules on the cell surfaces of all nucleated cells. It interacts and stabilizes the tertiary structure of the major histocompatibility complex class 1 alpha-chain . It is aWe report the co-occurrence of HBV and HDV in relation to their 2βM concentration in a rural population. To our knowledge this is the first study in Nigeria to use 2-β-microglobulin to evaluate the state of HBV/HDV co-occurrence.A total of 368 blood samples were collected from apparently healthy individuals in a rural suburb in South West Nigeria. Participants included in this study were either HBV positive or HDV positive or both and must have lived in the study population for the past 1 year. All participant confirmed participation, parental consent was obtained for children below the age of 18. HBV, HDV mono-infected individuals served as controls.Sera were separated from whole blood by centrifuging at 3000 rpm and tested for hepatitis B surface antigen (HBsAg), HDV and 2βM using the quantitative ELISA technique for all the 3 parameters and test performed as directed by the manufacturer of the ELISA kit . Absorbance of all the samples was read on a microplate reader  at 450 nm optical density. HBsAg, HDV and 2βM concentration was determined using curves from myassays ELISA analysis on line software for all samples plotted against the standards.Data analysis was done using the openepi which is an online epidemiological software and SAS University Edition determining seroprevalence of HDV in HBsAg positive patients and expressed as percentage of the study group/Pearson Chi square was used to determine the association between the concentration of 2βM and HBV/HDV infection. Linear correlation analysis was used to determine the association between age and the concentration of 2βM and HBV/HDV infection.2 = 271.9; p ≤ 0.0000001) shows that there is significant difference between all results across the table. Figure 2 = 271.9; p ≤ 0.0000001).Of the 368 samples tested for HBsAg, 240 (65.2%) were females while 128 (34.8%) were males, 66 (17.9%) were positive to HBsAg of which 39 (59.1%) were females and 27 (40.9%) were males. A total of 33 (50%) individuals were coinfected with HBV and HDV of which 8 (24.2%) were males while 25 (75.8) were females. Eight individuals (2.1%) were monoinfected with HDV from which there were 4 (50%) males and 4 (50%) females  despite available vaccines against the virus in Nigeria a rise from Umolu et al.  and AlaoEight individuals 2.1%) were monoinfected with HDV from which there were 4 (50%) males and 4 (50%) females (Table % were moThis study confirms elevated 2βM concentration in HBV/HDV coinfected individuals. It is also suggested that 2βM concentration could also be used as a marker to complications that could arise due to HBV/HDV coinfection. We also conclude that there is little awareness campaign in the rural areas as to danger posed by HBV and or HBV/HDV coinfection. Therefore awareness campaign in the rural communities must be stepped up in order to reduce the rising HBV/HDV infection.We were unable to assay for other debilitating diseases that could lead to immunocompromise and then enhance HBV infection.We did not confirm other diseases that could cause increase in 2βM concentration but this did not undermine our results as we have HBV and HDV monoinfection served as controls.Confounding factors like chemicals not covered in this study are likely to cause elevated 2βM though there influence were taking care of by controls.


The simulation results show the bandwidth with absorptivity being larger than 90% is extended by about 2.8 times comparing with the conventional square ring absorber. The composable small cell, ultra-thin, and broadband absorption with polarization and incident angle insensitivity will make the absorber suitable for the applications of focal plane array terahertz imaging.We suggest and demonstrate the concept and design of sectional asymmetric structures which can manipulate the metamaterial absorber’s working bandwidth with maintaining the other inherent advantages. As an example, a broadband terahertz perfect absorber is designed to confirm its effectiveness. The absorber’s each cell integrates four sectional asymmetric rings, and the entire structure composed of Au and Si Its pixels integrated metamaterial absorber and the measurement showed that the fabricated absorber has nearly 90% absorption at 3.8 THz24et al. demonstrated an infrared bimaterial cantilever focal plane array integrated with metamaterial absorber to enhance the infrared imaging performanceIn 2011, Tao The metamaterial absorbers provide unprecedented ability to absorb energy of electromagnetic waves. The absorbed energy heats bimaterial cantilever to deform its optical-readout structure. To increase the sensitivity and reduce the response time of the cantilever sensor, relatively thin absorber which is compatible with MEMS-based bimaterial fabrication process is requiredet al demonstrated the metamaterial absorber in 200879101112131415161718192021222391012131516171819212223Since Padilla To overcome the limitations of prior works, we suggest the concept of sectional asymmetric metamaterial structures which can manipulate specific device’s working bandwidth with maintaining the inherent advantages of the device. In the following a broadband THz absorber based on the structures will be demonstrate to confirm this idea. The absorber integrates four sectional resonators into a small cell with inheriting the complete resonator’s advantages of polarization insensitivity and incident angle insensitivity, while the bandwidth with absorptivity being larger than 90% is extended to about 2.8 times. Its entire structure which is compatible with MEMS-based fabrication is only 1.9 μm thick. The small cell, ultra-thin, and broadband absorption will make the absorber suitable for the applications of optical-readout bimaterial cantilever focal plane array imaging sensor42526The basic idea of sectional asymmetric structures can be explained in such a simple way that multiple sectional structures in one cell result in coupling of multiple resonant frequencies. It will extend the bandwidth effectively by combing the frequency responses. As an example, P1 = 19.4 μm, P2 = 19 μm, P3 = 18.4 μm, and P4 = 18 μm, respectively. The gaps a, b, c, and d between the sectional rings are 2.2 μm and the width of the sectional ring is w = 3.8 μm. The period of one metamaterial cell is 22 μm.Next, we proposed a broadband THz absorber based on the above example to verify its effectiveness. The basic structure is a simple square ring resonator which has advantages of polarization insensitivity and incident incidence angle insensitivity3N4 which are compatible with MEMS-based fabrication. It comprises three layers: the top layer is an array of sectional asymmetric Au resonators (0.1 μm thick); the middle layer is Si3N4 dielectric film (t = 1.7 μm thick); the bottom layer is Au ground (0.1 μm thick). The thermal, mechanical, and optical properties of Au and Si3N4 make the absorber suitable for applications of bimaterial cantilever focal plane array optical readout imagingThe absorber is made of Au and Si1/2 = 1, which ε stands for the normalized electric permittivity, μ is the normalized magnetic permeability, and Z represents the normalized free space impedance. The sectional square ring (Au bracket) is an example of electric ring resonator (ERR) and couples strongly to uniform electric fields, but negligibly to a magnetic field. By adding a ground plane, the magnetic component of the incident electromagnetic wave induces a current in the sections of the ERR that are parallel to the direction of the E-filed. The electric and magnetic response can then be tuned independently. The ERR determines the electric response while the dielectric type and thickness between the ERR and the ground plane determines the magnetic response. 2) In this design, the resonant frequency of the absorption peak is mainly determined by the outer side length P of basic square rings. Therefore, we integrate four sectional square rings with different size (P1–P4) to support multiple resonant modes closely positioned together in the absorption spectrum. By tuning the thickness of the dielectric film, the sectional asymmetric structure can be impedance-matched to free space at each resonant frequency and absorption broadening is achieved.The physical concepts and explanation of the bandwidth broadening are as follows: 1) To realize perfect absorption the impedance of the absorber should be matched to that of free space, for example: μ = ε then Z = (μ/ε) R stands for electromagnetic loss of the Si3N4 dielectric film. The four sectional square rings are equivalent to four parallel RLC circuit. R1, R2, R3, R4 represent ohm resistance of the four Au sectional rings. L1, L2, L3, L4 stand for equivalent inductance and C1, C2, C3, C4 are equivalent capacitance of the four sectional rings, respectively. According to the RLC circuit model, the resistance will not affect the resonance frequency, so we omitted it for simplicity. The inductance and capacitance can approximately describe the resonance of sectional asymmetric structures. The inductance of each sectional square ring can approximately be given by Li ~ (t/w) · Pi, where t is thickness of the Si3N4 dielectric film, w is the width of the sectional ring, Pi is the outer side length of the basic square ring. The capacitance can be expressed by Ci ~ (Pi · w)/t. Then the resonance frequency of the specific sectional ring is given by30To provide a further interpretation, the Transmission line model of the sectional asymmetric metamaterial cell is described in i represent the sectional ring resonators. The f is an approximate linear function of 1/Pi. Therefore, four sectional square rings will correspond to four resonance frequencies. The bandwidth of the absorber will be broadened by optimizing and adjusting the four outer side lengths P1, P2, P3, and P4.Here 1/2 to free space to minimize the reflectance. The absorber’s reflectance and transmission can be acquired by simulating the complex frequency dependent S parameters, S11 and S21A is calculated byThe proposed absorber can be regarded as an effective media and characterized by a complex electric permittivity ε and complex magnetic permeability μ. The resonance structures couple strongly to the electric or magnetic fields and match the impedance Z = (μ/ε)R = |S11|2 and T = |S21|2 are the reflectance and transmission, respectively. In our design the transmission T is zero because of the Au ground. Therefore, the absorptivity can be given by A = 1−R.where 3N4 dielectric film is 1.7 μm and the dielectric constant is 8. The material of the sectional ring is Au with an electric conductivity 4.6 × 107 s/m and the thickness of the ring is 0.1 μm. The unit cell boundary condition with Floquet-port was used to simulate the absorption spectra, because the Floquet mode can be applied to any periodical array whether mirrored or rotated. The absorptivity curve of sectional asymmetric absorber is shown in We modeled the sectional asymmetric structures and simulated the electromagnetic characteristics by the commercial 3D electromagnetic simulator CST Studio Suite 2012. The thickness of its SiP4 = 18 μm. The layer and materials are the same as the proposed sectional asymmetric broadband absorber. Furthermore, as a comparison we modeled an absorber based on a complete square ring structure. The period of its unit cell is 22 μm and the outer side length of the square ring is x axis and depicted as the inset in In application of focal plane array THz imaging, the sensor integrated absorber should be insensitive to the incidence angles, especially for the optical-readout cantilever sensor which will deflect angles owing to the bimaterial thermal effect, and the absorber should be polarization insensitive to maximize the absorption. To evaluate these characteristics, we simulated the absorption spectra of sectional asymmetric broadband absorber in different polarization angles and incidence angles by the CST2012. Aaverage stands for the average absorptivity at the different polarization angles, Aφ = 0°, Aφ = 10°, …,Aφ = 160°, Aφ = 170° represents the absorptivity at polarization angles φ = 0°, φ = 10°, …,φ = 160°, φ = 170°, respectively.where The major metrics to define polarization-insensitive are 1) the absorptivity; 2) the resonance frequency. The absorbers which are sensitive to polarization will have severer absorptivity decline and resonance frequency shiftk and the surface normal of the absorber and is depicted as the insets.According to the 3N4 is only 1.9 μm thick. The simulation results show its bandwidth with absorptivity being larger than 90% is extended to about 2.8 times comparing with the classic square ring absorber.The paper proposed the concept of sectional asymmetric structures. They can manipulate specific device’s working bandwidth with maintaining the properties of the basic structure. To verify its effectiveness a broadband THz absorber was designed and evaluated numerically. Each cell of the absorber integrates four sectional square rings with approximate resonance frequencies. The entire structure composed of Au and SiWe believe the sectional asymmetric structures have two distinctive advantages: 1) manipulating specific device’s working bandwidth while maintaining the inherent advantages of the complete structure; 2) not increasing size of the structure and thickness of the device. Therefore, it will be suitable for the focal plane array THz imaging sensors such as optical-readout bimaterial cantilever sensors or some electrical-readout sensors (microbolometer sensors and pyroelectric sensors).There are four steps to design a normal sectional asymmetric structure (or cell). The first step is choosing one complete resonance structure as basic structure. The second step is dividing the symmetrical structure into sections. The third step is varying the characteristic size of each section. The fourth step is composing these asymmetric sections into a new structure (cell). Then, we called it sectional asymmetric metamaterial structure. It should be mentioned that the selected basic structure in the first step should be multiple symmetric structures, such as square ring, hexagonal ring, circular ring, or elliptical ring and so on.3N4, but its basic structure is circular ring. The absorber comprises three layers: the top layer is an array of sectional asymmetric Au resonators (0.1 μm thick); the middle layer is Si3N4 dielectric film (1.8 μm thick); the bottom layer is Au ground (0.1 μm thick). We take another simple example to demonstrate the design method. This example is also a metamaterial absorber made of Au and Si3N4 dielectric film is 1.7 μm and its dielectric constant is 8. The material of the sectional ring is Au with an electric conductivity 4.6 × 107 s/m and the thickness of the ring is 0.1 μm.We modeled the cell structures and simulated their electromagnetic characteristics by the commercial 3D electromagnetic simulator CST Studio Suite 2012. We use auto meshing technology and frequency-domain solver to acquire S-parameter. The unit cell boundary condition with Floquet-port was used to simulate the absorption spectra, because the Floquet mode can be applied to any periodical array whether mirrored or rotated. The resonance current distributions were obtained based on the Field Monitor technology of the CST at certain frequencies. The thickness of SiHow to cite this article: Gong, C. et al. Broadband terahertz metamaterial absorber based on sectional asymmetric structures. Sci. Rep.6, 32466; doi: 10.1038/srep32466 (2016).


We studied the effect of TNFα on the autoregulatory mechanism that regulates CBF in response to increased viscosity using dextran solutions, in ciliated cells cultured from human pediatric epithelial adenoid tissue. Cultures were treated with TNFα, before and after the viscous load was changed. TNFα treatment produced a significantly larger decrease in CBF in cultures exposed to dextran. Furthermore, an increment in [Ca2+]i was observed, which was significantly larger after TNFα treatment. In conclusion, although TNFα has deleterious effects on ciliated cells in response to maintaining CBF after increasing viscous loading, it has a positive effect, since increasing [Ca2+]i may prevent the MCC collapse. These findings suggest that augmented levels of TNFα associated with an inflammatory response of the nasopharyngeal epithelium may have dual effects that contribute to maintaining the effectiveness of MCC in the upper airways.In airway epithelium, mucociliary clearance (MCC) velocity depends on the ciliary beat frequency (CBF), and it is affected by mucus viscoelastic properties. Local inflammation induces secretion of cytokines (TNF Mucociliary clearance (MCC) is a critical defense mechanism as it removes microbes and contaminants from the airway. The epithelium of the upper and lower airways system is composed of ciliated cells, whose ciliary beating removes the mucus layer that covered the epithelium. The MCC velocity is determined by ciliary beat frequency (CBF) and viscosity of the mucus layer . Bacteriα) is a proinflammatory cytokine produced primarily by cells of hematopoietic origin, including myeloid lineage such as monocytes and macrophages i through the activation of the transient receptor potential vanilloid 4 channel, which produces an increment of [Ca2+]i by the release of this ion from intracellular stores at lower viscous load  or the entry of calcium from extracellular space at high viscous load  i) were determined using a spectrofluorometric technique described previously i increment associated to the effect of TNFα on CBF response to increase viscous loading, cultures were previously incubated for 48 hours with TNFα (10 ng/mL). Then cultures were treated with either Thapsigargin 2.5 μM  for 30 min or Gadolinium 100 μM  for 5 min, previous to the change in viscosity of the medium. Thapsigargin was dissolved in dimethyl sulfoxide (DMSO) at a final concentration of 0.1%. At this concentration, DMSO had no effect on CBF.To determine the source i was measured in cultures exposed to 10% dextran and pretreated for 48 hours with TNFα. A slight increase in [Ca2+]i was observed after viscosity of the cultures was changed, which was significantly higher in cultures pretreated with TNFα  compared to cultures treated only with TNFα (17.03 ± 1.13%) or to controls (9.28 ± 3.4%), when the viscosity of the medium was increased (10% dextran) , when the viscosity of the medium was changed  was observed compared to control cultures (9.28 ± 3.4%). Similar decrease of CBF was observed in cultures pretreated with TNF Figures .α, a proinflammatory cytokine, produced a significant decrease in CBF response to changes in viscous loading (10% dextran), but has a positive effect, since we observed an increase in [Ca2+]i that may prevent the MCC collapse. Although, the changes in CBF observed after increasing the viscosity in the presence of TNFα represent a decay of up to 30% of the CBF with respect to basal CBF, it is well established that MCC velocity is directly dependent on CBF and that small changes in CBF have a substantial effects on MCC effectiveness i that it was significantly augmented after incubation with TNFα for 48 hours. In airway smooth muscle cells, it has been shown that TNFα increased [Ca2+]i by modifying mitochondrial calcium concentration i observed after TNFα incubation could protect cells from a worse cilia slowing and the recovery of CBF to basal ciliary activity, after viscous loading.In this study, cultures exposed to an increased viscosity (10% dextran) produced a slight increment in i, we monitored changes in CBF in cultures exposed to 10% of dextran and TNFα in the presence of an inhibitor of calcium uptake (Thapsigargin) or a calcium channel blocker (Gadolinium). Our results showed that Ca2+ from the cytosolic reservoir and the extracellular influx contribute to maintaining the augmented levels of [Ca2+]i, to prevent a further decrease of CBF induced by the additive effect of viscous loading and TNFα. The combined action of TNFα and 10% dextran on CBF on ciliated cells from adenoid tissue seem to simulate the effect of high range viscosity (20% dextran), where the autoregulatory mechanism depends mainly on extracellular calcium influx i i , 43, 44.α has a negative effect upon the response of human nasopharyngeal pediatric airway ciliated cells to viscous loading. However, TNFα incubation also has a beneficial effect, since it induces an increment in [Ca2+]i that contributes to maintaining the effectiveness of MCC in the upper respiratory tract. Further studies are required to advance our understanding of the mechanism of intracellular calcium homeostasis affected by TNFα, in order to prevent the collapse of MCC observed in chronic airway diseases.In conclusion, our findings suggest that, during acute inflammation, where mucus viscosity and secretion of cytokines in airway are increased, TNF


Low-dimensional layered perovskites with metal halide slabs separated by the insulating organic layers are reported to show higher stability, but the efficiencies of the solar cells are limited by the confinement of excitons. In order to explore the confinement and transport of excitons in zero-dimensional metal–organic hybrid materials, a highly orientated film of (CH3NH3)3Bi2I9 with nanometre-sized core clusters of Bi2I93− surrounded by insulating CH3NH3+ was prepared via solution processing. The (CH3NH3)3Bi2I9 film shows highly anisotropic photoluminescence emission and excitation due to the large proportion of localised excitons coupled with delocalised excitons from intercluster energy transfer. The abrupt increase in photoluminescence quantum yield at excitation energy above twice band gap could indicate a quantum cutting due to the low dimensionality.A metal-organic hybrid perovskite (CH 3NH3)3Bi2I9.Understanding the confinement and transport of excitons in low dimensional systems will aid the development of next generation photovoltaics. Via photophysical studies Ni et al. observe 'quantum cutting' in 0D metal-organic hybrid materials based on methylammonium bismuth halide (CH The importance of the 3D framework to the transport of charge carriers can be evidenced by performance dependence on crystal orientation in layered two-dimensional (2D) perovskites1. For example, in the photovoltaic context, films of 2D Ruddlesden–Popper phases, with randomly distributed crystallites, have shown promising stability, but poor efficiency at only 4.73%2 in contrast to the efficiency of around 20% in 3D perovskites3, which could be attributed to the inhibition of out-of-plane transport due to the insulating organic groups5. On the contrary, with careful control of crystallinity and anisotropy, a 2D perovskite can also show high performance close to 3D perovskites1. As a collateral effect of this confinement of charge carriers in the atom-scale slab that increases the exciton recombination, the low-dimensional layered perovskites with layered corner-sharing (BX6)4− separated by organic cations have been reported to show structural relaxation and high luminescence when the thickness is decreased to few unit cells6. The dimensionality of a 2D perovskite can be reduced further to zero-dimensional clusters, noted as (BnXm)j− surrounded by Ak+ , by tuning the crystallography and valence of cations and anions7. For example, organic–inorganic hybrid bismuth halide can generate a single (BiX6)3− octahedron8, face-sharing (Bi2I9)3− or edge-sharing (Bi2I10)4− bioctahedra10, which have a size of ~1 nm separated by organic groups.Metal–organic hybrid perovskites share the formula of ABX11. For example, QDs of Si and PbS can efficiently generate multiple excitons from one high-energy absorbed photon following a mechanism known as carrier multiplication (CM) owing to their discrete energy levels and enhanced Coulomb interactions14. This is one of the suggested phenomena that may allow the efficiency of a single-junction solar cell to exceed the Shockley–Queisser limit15. The production of additional electron–hole pairs is expected to be greatly enhanced in QDs because their limited electron density of states greatly reduces the electron–phonon interactions12; however, for a solar cell using PbS QDs as an absorber, the large number of higher-lying energy levels due to surface defects were reported to decrease CM16. This could be alleviated by surface passivation with ligands17, alternatively this might also be achieved by protecting with the organic cation in zero-dimensional hybrid organic–inorganic halides. Moreover, the intrinsic junction between the negative charge on the low-dimensional (BnXm)j− cluster and opposite charge on the surrounding organic Ak+ could cause an internal electric field that controls the broadband emission that could be tuned via the electronegativity of the core cluster and surrounding organic groups18.Nanometre-sized quantum dots (QDs) can display optical, electronic, and structural properties that often are not present in either isolated molecules or macroscopic solids19. A metal–organic material with the formula (CH3NH3)3Bi2I9 (MABI) that contains quantum confined clusters/dots of (Bi2I9)3− has been reported as an effective absorbing material in a solar cell, but the performance was low, 0.1%21. With a small size (around 1 nm) of (Bi2I9)3−, MABI showed a separate excitonic peak in the absorption spectra due to the confinement of charge carriers, and the binding energy of charge carriers has been estimated to be over 0.3 eV22. An analogous explanation on the even poorer performance compared to the 2D layered perovskite could be the enhanced confinement of charge carriers, but this explanation has not been elucidated because the performance of a solar cell depends on multiple parameters, such as the band energy alignment of different components and the microstructure of the layers. In a more recent study, MABI shows a double-peak emission including one close to band gap coupled with one in the blue light region and is superior in stability over lead-based perovskite in ambient air24. Interestingly, long-lived excitons on the scale of nanoseconds have also been observed, which contrasts with the low performance of devices based on MABI24. In this study, we synthesised a highly orientated MABI film to explore these issues. We studied the photoluminescence (PL) anisotropy and lifetime of excitons on these low-dimensional hybrid materials in order to understand the charge-carrier transport property. The PL at high excitation energy above twice the band gap (Eg) seems to show an enhancement in quantum yield that may be explained in terms of CM25, which could open up a horizon of low dimensionally bonded hybrid materials for third-generation photovoltaics.The coupling between QDs and perovskite is of interest since the heterocrystals of QDs embedded in perovskites exhibit remarkable optoelectronic properties that are traceable to their atom-scale crystalline coherence that involves the efficient transport of excitons between them24. The materials show hexagonal symmetry (P 63/mmc) and the face-shared BiI6 bioctahedra or (Bi2I9)3−clusters are separated by CH3NH3+ groups. The unit cell is a = 8.5821(3) Å and c = 21.7678(8) Å, leading to a volume of 1388.46(11) Å3 and a density of 3.8 g cm−3. Considering the size of an iodine anion, the (Bi2I9)3−clusters are ca. 1.11 nm in size and are separated from each other by ca. 0.16 nm. The density of the (Bi2I9)3− clusters is 1.69 × 1027 cm−3, which is much higher than the likely concentration of nanoparticles (1017–20 cm−3) suspended in solvent25. The thermal stability of MABI as a function of temperature was studied with differential scanning calorimetry, and no phase transformation was observed between −50 and 140 °C 3−clusters at the atomic level behaves like the atomic ligands that separates and passivates PbS QDs17.Figure a = 8.5792(1) Å, c = 21.7588(4) and V = 1386.95(5) Å3, are in good agreement with those previously reported for MABI24. The X-ray photoemission spectroscopy (XPS) and Raman spectroscopy on the prepared film 3Bi2I9 (2.47 eV27) containing (Bi2I9)3− clusters but with a larger organic group. Since this peak is usually assigned to the (Bi2I9)3− group22, the organic group does not contribute to the absorption at this energy level. The lowest exciton state arises from excitations between the valence band, which consists of a mixture of Bi(6 s) and I(5p) states, and the conduction band, which derives primarily from Bi(6p) states, and is confined zero-dimensionally in the bioctahedra Bi2I93−27. Substitution of Cs or formanidinium on methylamonium (MA) site in MAPbI3 has been shown to cause significant shift (larger than 100 meV) of the band edge28, contrasting with MABI where the band gap is unchanged between Cs and MA20.Figure  = 8.5792 Å, c = 2= 21.7588 and V = 2I93− clusters could be viewed as QDs with organic groups as separators, resembling a core–shell structure due to the nanometre size of the photoactive Bi2I93− clusters. Since the MABI crystals are aligned in the <002> direction on the quartz substrate and orientated randomly in the perpendicular directions, there would be PL anisotropy in the <002> direction. PL anisotropy is investigated by varying the angle of the coating with the incident beam while fixing the position of the detector. Distinct PL spectra are obtained as shown in Fig. θ. On the other hand, the cathodoluminescence (CL) of MABI coating in Supplementary Fig. 29. Specifically, the penetration depth of the electron beam of 5 keV would be around 200 nm based on the density of 3.8 g cm−3. This difference makes the actual incident angle of a high-energy electron beam in CL very difficult to control because of the re-absorption of photons.The fundamental property of a crystalline material is the periodic spatial arrangement of atoms and clusters. The MABI crystals containing periodically aligned Biλdet = 650 nm) can be fitted by four peaks  or the increasing emission overlap of trapped states.The PL excitation (PLE) technique allows one to measure all the allowed intersub-band absorption transitions, and therefore to make a much more complete characterisation of low-dimensional system. The PLE spectra Fig.  for emisdet Fig.  show disθ = 0°; Fig. λex = 375 or 450 nm) close to the PLE peaks, while detecting emission, λdet, is between 580 and 660 nm. When excited at 375 nm the samples show very fast , slower (τ = 10 ps) and very slow (τ > 2 ns) PL decays, while when excited with 450 nm light it is just very fast (τ < 1 ps) and very slow (τ > 12 ns). The picosecond excitons under 450 or 375 nm excitation could perhaps be inside the cluster of Bi2I93− and the distinct lifetime profile indicates that the emissions at these two excitations are from trapped states of different sites. The early-time emission , the Stokes shift causes lower-energy emission when an emitted photon from one crystal is reabsorbed by a neighbouring one. Because of the anisotropic nature of the Bi2I93− cluster, two main peaks rather than one are observed according to the anisotropic PL of a coating, and a Stokes shift energy of 0.13 eV can be obtained from the PL spectra. As the band gap of the highly orientated film (θ = 0°) is determined to be 2.19 eV, while the peak energy of PL singlet at θ = 25° is 1.86 eV, giving a binding energy in this situation ~0.33 eV at low angles. Kawai et al. studied the absorption of MABI single crystals of different thicknesses in the temperature range between 78 and 301 K, and the excitonic nature of the absorption peak at 2.43 eV was proven via the fitting of Urbach tail at the low-energy side of the peak and the binding energy was estimated to be higher than 0.3 eV22. The Stokes shift of the powdered sample is lowered to 0.13 eV because of the higher-energy level at higher angles, as illustrated in Fig. 25 under each excitation energy as shown in Fig. Eg, implies that the possible CM process happens possibly via the impact ionisation mechanism as simulated by Allan et al.32 In MABI, a second (Bi2I9)3− may be excited by a neighbouring (Bi2I9)3− cluster containing a hot electron–hole pair, since the 0.11-nm separating distance controlled by the size of CH3NH3+ groups is sufficiently small to facilitate the energy transfer. MABI contains a small number of delocalised excitons with lifetime on the scale of nanoseconds, but such systems can still be expected to produce CM33. The difference in the lifetime of excitons at λex = 450 and 375 nm showed limited impact on either the PL intensity or PLQY. The Tauc plot 3−, surrounded by positive CH3NH3+ seems to facilitate the localisation of excitons. The resultant anisotropic electron density would give rise to the Stokes shift in the PL. A small portion of long-lived excitons arises from the coupling and energy transfer between the clusters. The quantum yield from the QD core clusters separated by insulating organic cations is seen to increase when the excitation is above 2Eg, indicating quantum cutting.A low-dimensional hybrid material, MABI, showing a band gap of 2.19 eV and absorbing visible light has been obtained via solution processing. The film resulting from drying the solution showed a high degree of preferred orientation in the <002> direction. The close coordination between the negatively charged core cluster, (Bi2O2(CO3)  was dissolved in hydroiodic acid (HI)  using ethanol as solvent (500 ml) and then the product, BiI3, collected after the solution was evaporated at 80 °C. Methylammonium iodide was prepared by reacting methylammonia (24 ml) solution in hydriodic acid solution (10 ml) in ethanol (100 ml). The solvent was removed at 50 °C using a rotary evaporator. The resulting white solid was washed in diethylether and dried in a vacuum oven overnight.Bi3 and CH3NH3I (1:2 in mole ratio) were dissolved in dimethyl formamide (DMF) to form a clear solution  when heated at 60 °C with stirring. The solution is spin-coated on to a fused silica substrate at 2000 r.p.m., and dried in air for 30 min before baking on a hotplate at 100 °C for 1 h. Absorption measurements were carried out using a Cary Varian 300 spectrometer. PL emission and excitation spectroscopy of the coating were performed on a FLS980 spectrometer  and ultrafast luminescence measurements were performed using up-conversion spectroscopy. CL was carried out on an inclined sample in a low-vacuum field emission SEM using a 5 keV, 1.5 nA electron beam. The luminescence was collected using a reflecting objective, dispersed with a 1/8-m spectrograph and detected with an electron-multiplying CCD. X-ray photoemission spectra and Raman spectra on the coating were carried out on Kratos Axis Ultra DLD photoelectron spectrometer and Lab Ram 300 (Horiba Jobin Yvon SAS), respectively, and more detail and analysis were provided in α target (λ  = 0.15418 nm), and unit cell parameters of the powdered sample were analysed using General Structure Analysis System software. The absorption of the powdered sample was recorded with a V650 spectrophotometer (Jasco). PL of the powder sample was measured on a Horiba Jobin Yvon spectrofluorometer and the powder was sandwiched between two quartz plates with an illuminated spot size of about 0.6 cm2.BiIhttp://dx.doi.org/10.17630/b8144269-6d3d-4a2a-afe2-e68fc51f962e.All new data associated with this manuscript are available from the University of St Andrews repository Supplementary InformationPeer Review File


Temperature dependent structure analyses indicate the simultaneous weakening of both interactions as temperature increases. Infrared spectroscopy of the MOF confirmed that the CO2 interaction with the framework is temperature dependent. The strength of the interaction is correlated to the separation of the two bending peaks of the bound CO2 rather than the frequency shift of the asymmetric stretching peak from that of free CO2. The encapsulated CO2 in the cage is weakly interacting with the framework at around ambient temperatures and can have proper orientation for wiggling out of the cage through the narrow portals so that the reversible uptake can take place. On the other hand, the CO2 in the cage is restrained at a specific orientation at 195 K since it interacts with the framework strong enough using the multiple interaction sites so that adsorption process is slightly restricted and desorption process is almost clogged.The MOF with the encapsulated CO Temperature dependent vibrational modes of bound CO2 are investigated using infrared (IR) spectroscopy together with temperature dependent crystal structures with the encapsulated CO2. Reversible CO2 uptakes at around ambient temperatures but irreversible CO2 uptake at 195 K could be explained based on temperature dependent structural information and vibrational band analyses of the bound CO2.Here, we report the temperature dependent single crystal structure analyses of a microporous MOF with bound CO2 with tetrazole (tz) in methanol (MeOH)/acetonitrile mixed solvent produced block-shaped blue crystalline product of the formula unit, Cu3Cl2(tz)4(MeOH)2 ((MeOH)2@1a). A single crystal structure analysis revealed that the product is a 3-D MOF of an 8-c bcu topology3Cl2] secondary building unit (SBU) as an 8-c node and tridentate tz as a ditopic linker  (MeOH)2@1a at 160 °C for 7 d (2-bound 1a ((CO2)0.8@1a-195K) were obtained by keeping single crystals of 1a in CO2 at ~1.5 bar and at ambient temperature for an hour, and then cooling down to 195 K. The structure analysis revealed that CO2 was ligated to unsaturated metal site using its Lewis basic oxygen atom in an angular η1-(OA) coordination mode with a 0.40(1) site occupancy factor (0.8 CO2 molecule per cage)  Å, is slightly longer than the Cu−OMeOH distance, 2.617(4) Å, of the bound MeOH in the as-synthesized crystal but still significantly shorter than the sum of their van der Waals radii sum (3.55 Å)CO2 distance is, much longer than the corresponding Ni-OCO2 bond distances in Ni-MOF-74 structure obtained from the PXRD experiment, 2.29(2) ÅCO2 bond distances in Mg-MOF-74 structures obtained from the NPD experiments, from 2.24(3) Å to 2.39(6) Å2 molecule can interact with the Lewis basic nitrogen atom in the pore environment161718192-bound 1a. The Lewis acidic carbon atom (C1C) of the bound CO2 molecule is interacting with the two Lewis basic nitrogen atoms (N3) of two symmetry-related tz ligands. The distance between C1C and N3 (3.21(2) Å) is slightly shorter than their van der Waals radii sum (3.30 Å). The Cu2-O1C-C1C bond angle (124(2)°) is in the range those in Ni-MOF-74, Mg-MOF-74, and Cu-MOF-74 structures (from 117(2) to 144(2)°). The observed site occupancy factor of the ligated CO2 molecule, 0.40(1), is due to steric repulsion between the CO2 molecules bound to the symmetry-related Cu(II) sites in a cage. The interatomic distance between the symmetry-related ligated oxygen atoms of the bound CO2 molecules (2.647(2) Å) is much closer than their van der Waals radii sum (3.1 Å)  Å and 1.13(3) Å, in the bound CO2 structure are not distinguishable to that in the free CO2 structure, 1.155(1) Å2 is due to the combined effect of two different interactions between the CO2 molecule and the framework. The CO2 molecule donates its σ electron to the metal center through the ligating oxygen atom but simultaneously accepts σ electron from the two Lewis basic nitrogen atoms of the tz ligands through the Lewis acidic carbon atom of the bound CO2. The O−C−O bond angle in the bound CO2 structure, 176(3)°, is also nearly linear as that in the free CO2 structure.The properly activated sample,  for 7 d –S7. Singer cage)  and S8.  (3.1 Å) . The steCO2)0.26(H2O)0.15@1a-296K-5h  showed the bound CO2 molecule in the cage with reduced site occupancy, 0.13(2) 0.26(H2O)0.15@1a-296K-5h at 296 K, 3.09(5) Å, is elongated by ~0.15 Å than that of (CO2)0.8@1a-195K at 195 K but is still slightly shorter than the van der Waals sum of Cu and O atoms. However, interestingly, the Lewis acidic carbon atom (C1C) of the bound CO2 molecule is no longer interacting with the Lewis basic nitrogen atom (N3) of the ligand. The distance between C1C and N3 (3.34(4) Å) is slightly longer than their van der Waals radii sum, 3.30 Å. The complete replacement of the bound CO2 molecules in the pore by the water molecules in air took 10 days at ambient condition  . Though ondition  and S9.1a, filled with 12CO2 molecules in the bending and asymmetric stretch regions  coordination mode in Ni-MOF-742 molecule to the framework and a larger separation indicates stronger interaction between them. The separation between the two peaks decreases as the temperature increases from 5.49 cm−1 at 103 K to 4.92 and 4.67 cm−1, respectively, at 293 and 423 K. Provided that the binding energy is proportional to the separation, the binding energy at 293 and 423 K, respectively, decreases by 11 and 15% compared with that at 103 K. The CO2 molecule encapsulated in the cage is less strongly bound to the framework at elevated temperatures. These observations are in agreement with the temperature dependent crystal structures of CO2@1a. Though the bound CO2 structures themselves from the temperature dependent single crystal structure study are not as sensitive as the bending modes of the bound CO2 molecule, the temperature dependent interactions between the CO2 and the framework are in good agreement with the temperature dependent bending modes of the bound CO2 molecule. While the peak separation of the two symmetric bending modes of the bound CO2 molecule is temperature dependent, the center frequency is insensitive to temperature. Temperature insensitivity of the center frequency is due to the combined result of simultaneous weakening of both the sigma electron donation to the Cu(II) ion through the Lewis basic oxygen atom of the bound CO2 and the sigma electron acceptance from the nitrogen atoms of the tz ligands via the Lewis acidic carbon atom of the bound CO2 molecule.−1 with a FWHM of ~7 cm−1 is red-shifted by 14 cm−1 compared to the corresponding band of free 12CO2 at 2349 cm−1 2 to the Cu(II) center is slightly stronger than the σ electron acceptance through the carbon atom of the bound CO2 from the nitrogen atoms of the tz ligands. An asymmetric stretching band shift is not a good indicator of the binding strength of an encapsulated CO2 to a framework. It is a combined effect of electron donation and acceptance of the encapsulated CO2 to and from the framework. The encapsulated CO2 in the series of isostructural MOFs, M-MOF-74 , Mg(II), Zn(II), and Co(II)), showed different shifts of the asymmetric CO2 stretching band depending on metal ions even though the frameworks are isostructural2 inside the cage. At the lower-frequency side of the main band, two peaks, each of which is enclosed with a rounded rectangle, are observed. The temperature dependent peak at ~2323 cm−1 was assigned as a vibrational hot band coming from the transition,  =  → −1, which shows similar temperature dependence as the peak at ~2323 cm−1, was assigned to be a peak arising from CO2 double occupancy in a single cage (two CO2 molecules in a single cage interacting to each other). 2 by a factor of 3. The integrated areas of the peaks in the spectra of the low CO2 content sample are about 1/3 of those of their corresponding spectra , H2 (at 77 K) and CH4 (at 195 K and 308 K) adsorptions (1a shows reversible CO2 uptake at 273 K even though the kinetic diameter of CO2 (3.3 Å) is much larger than the dimension of the portal window and the isotherms are of a typical type I  center). The CO2 sorption isotherms of 1a at 298 K are also reversible type I isotherms and the total CO2 uptake amount at ~1 bar is 37.4 cm3/g, which is slightly larger than the CO2 uptake amount at 273 K and ~1 bar. The increased CO2 uptake amount at the higher temperature is due to increased double occupancy of CO2 molecules in a single cage and subsequent pore filling up to the cages located at the inner parts of the microporous 1-D channels. The total CO2 uptake amount at 313 K and ~1 bar, 31.3 cm3/g, is slightly smaller than that at 298 K. The reduced CO2 uptake amount is due to decreased CO2-framework interaction at the higher temperature. The adsorption enthalpy (−ΔHads) of CO2 on 1a calculated using the adsorption isotherms at 298 K and 313 K is −32– −25 kJ/mol  of CO2 estimated using desorption isotherms at 298 K and 313 K is −41– −35 kJ/mol, which is comparable to the CO2 adsorption enthalpy on Mg-MOF-74, ~40 kJ/mol22Even though orptions . Howeverl type I . The lar5 kJ/mol , which w2 sorption on 1a at 195 K is irreversible , which is much smaller than the expected maximum amount, one CO2 molecule per cage . Significant portions of the inner cages in the 1-D porous channel may not be accessible for CO2 molecule because the channels are already blocked by the CO2 molecules bound strongly to the framework as shown in 2 desorption even at 0.0015 bar.Interestingly, the COversible . The CO2hopping process of a CO2 molecule into an empty cage but also filling process of a second CO2 molecule into the cage with an encapsulated CO2 molecule are allowed so that even most of the empty inner cages of the 1-D channels could be occupied with CO2 molecules and the CO2 molecules in the inner cages the 1-D channels can also be emptied via a reverse process. However, at low temperature, the filling of a second CO2 molecule into the cage with an encapsulated CO2 molecule is severely hindered because the CO2 molecule bound strongly at the open metal center does not allow the second CO2 molecule into the same cage. At low temperature, the main pore filling is via hopping process so that the maximum amount of CO2 captured in the 1-D channels is significantly smaller than the expected maximum amount of CO2. When multiple consecutive cages in a 1-D channel are filled with CO2 molecules, desorption of CO2 is also severely hindered, which is the cause of the irreversible CO2 sorption behavior of 1a at 195 K.At high temperature, not only 2 molecules, the CO2 uptake amount is only ~0.9 CO2 molecule per cage at 298 K and 1 bar, which is due to the steric repulsion between the two bound CO2 molecules in the cage. Temperature dependent single crystal structure analyses revealed that the interaction between the bound CO2 molecule and the framework of the MOF is temperature-dependent. As temperature increases, both the CO2 coordination to the unsaturated Cu(II) center and the Lewis acid−base interaction between the carbon atom of the CO2 molecule and the nitrogen atom of the ligand are simultaneously weakened.Although each cage contains two unsaturated Cu(II) sites and the cage size is large enough for two CO2 molecule indicate that the electron donation to the metal center through the oxygen atom of the CO2 molecule is slightly larger than the electron acceptance from the nitrogen atom of the ligand through the carbon atom of the CO2 molecule. The temperature dependent separation of the two bending peaks also supports the temperature dependent interaction between the CO2 molecule and the framework of the MOF. As temperature increases, the separation of the bending peaks decreases. The observation tells that the CO2–framework interaction decreases as the temperature increases as observed in the temperature dependent structure analyses of a single crystal of CO2@1a.The red-shifted vibrational peaks of the bound CO2 uptakes on 1a were observed at 298 and 313 K, respectively, even though the portal dimension of the cage aligned along the microporous 1-D channel is smaller than the kinetic diameter of CO2 molecule. The CO2 uptake amount per unsaturated Cu(II) center at 298 K, 1 bar is 0.45 molecule, which is only slightly smaller than the probable maximum value, 0.5. On the other hand, the irreversible CO2 uptake was observed at 195 K and the CO2 uptake amount per unsaturated Cu(II) center is only 0.30 molecule, which is much smaller than the expected value, 0.5. The decreased uptake amount at the lower temperature is due to the strongly interacting CO2 molecules in the cages aligned along the microporous 1-D channel hindering the other CO2 molecules to access the available inner cages in the 1-D channel. The different uptake behaviour at different temperature is related to both the small portal dimension of the cages aligned along the 1-D channel and the different strength of CO2−framework interaction in the cage. The reversible CO2 uptakes were observed at the higher temperature since the CO2 molecule interacting weakly with the framework could have proper orientation for the escape from the cavity through the small portal of the cages. However, the irreversible CO2 uptake was observed at the lower temperature since the CO2 molecule interacting strongly enough with the metal center in the cage could not have proper orientation for the escape from the cavity through the small portal.The reversible CO2 (0.203 mmol) was dissolved in 4 mL MeOH in a 10 mL vial, and then 0.90 mL 0.45 M tetrazole (tz) acetonitrile solution (0.41 mmol) was added into the solution. The Teflon-sealed vial was heated to 70 °C for 7 days and then slowly cooled down to ambient temperature. The block-shaped blue crystals obtained were washed using 10 mL fresh methanol and filtered.A 27.3 mg amount of CuClThe samples were in the form of a KBr pellet of a ~200-μm thickness and a 13-mm diameter. The samples were located in a cell composed of two circular KBr windows of a 25-mm diameter. The windows were separated by a 200-μm thick spacer with 25 and 20 mm outer and inner diameters, respectively. FTIR spectra were recorded by a Varian 7000e FTIR spectrometer. The samples with KBr windows were placed in a home-made oxygen-free high thermal conductivity (OFHC) copper cell, and the temperature of the samples was controlled and maintained in a variable temperature cell holder . Details of the temperature-controllable cell assembly have been reported elsewhereAll gas sorption isotherms were measured using a BELSORP-max  with a standard volumetric technique.How to cite this article: Kim, D. et al. Temperature dependent CO2 behavior in microporous 1-D channels of a metal-organic framework with multiple interaction sites. Sci. Rep.7, 41447; doi: 10.1038/srep41447 (2017).Publisher's note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.


AD) have led to an increased research interest on the involvement of the immune system in AD pathogenesis. A link between amyloid pathology and immune gene expression was suggested in a genome‐wide gene expression study of transgenic amyloid mouse models. In this study, the gene expression of lysozyme, a major player in the innate immune system, was found to be increased in a comparable pattern as the amyloid pathology developed in transgenic mouse models of AD. A similar pattern was seen at protein levels of lysozyme in human AD brain and CSF, but this lysozyme pattern was not seen in a tau transgenic mouse model. Lysozyme was demonstrated to be beneficial for different Drosophila melanogaster models of AD. In flies that expressed Aβ1‐42 or AβPP together with BACE1 in the eyes, the rough eye phenotype indicative of toxicity was completely rescued by coexpression of lysozyme. In Drosophila flies bearing the Aβ1‐42 variant with the Arctic gene mutation, lysozyme increased the fly survival and decreased locomotor dysfunction dose dependently. An interaction between lysozyme and Aβ1‐42 in the Drosophila eye was discovered. We propose that the increased levels of lysozyme, seen in mouse models of AD and in human AD cases, were triggered by Aβ1‐42 and caused a beneficial effect by binding of lysozyme to toxic species of Aβ1‐42, which prevented these from exerting their toxic effects. These results emphasize the possibility of lysozyme as biomarker and therapeutic target for AD.Genetic polymorphisms of immune genes that associate with higher risk to develop Alzheimer's disease ( ADAlzheimer's diseaseAβamyloid‐βAβPPamyloid‐β precursor proteinBACE1β‐site AβPP‐cleaving enzyme 1CSFcerebrospinal fluidPSEN1presenilin 1WTwild‐type1‐40 is the predominant secreted form, the longer Aβ1‐42 has a more prominent part in AD as it is more aggregation prone and forms toxic oligomers more easily Two of the main pathological hallmarks of Alzheimer's disease (AD) are extracellular accumulation of amyloid plaques, which consists of amyloid‐β (Aβ) peptides, and intracellular neurofibrillary tangles composed of hyperphosphorylated tau Drosophila melanogaster rescues both the survival and the activity of the Aβ flies Drosophila models of AD were used. Beneficial effects of lysozyme in these different Drosophila models were discovered; in flies that expressed Aβ1‐42 individually or AβPP together with BACE1 (AβPP–BACE1) in the fly eyes, the AD phenotype was completely rescued by lysozyme. In flies carrying the highly toxic Aβ peptide with the Arctic mutation (E22G), lysozyme increased the fly survival and improved the locomotor behaviour in a dose‐dependent manner. These results imply that lysozyme has a protective effect on Aβ toxicity and could function as a new therapeutic strategy for AD.Lysozyme, which belongs to the innate immune system, is upregulated in cerebrospinal fluid (CSF) from AD patients and inhibits the formation of toxic Aβ oligomers www.mouseac.com on five different amyloid or tau mouse dementia models. The mouse models were analysed at the ages 2, 4, 8 and 18 months r = 0.91 and 0.94 respectively) and in hippocampus (r = 0.86 and 0.95 respectively)  , while this sigmoid correlation relationship was weaker in cortex . These results demonstrate that the increase of Aβ plaque pathology can trigger lysozyme expression in the AD mice brain, while tau pathology has no immediate impact on lysozyme expression.To investigate whether the mRNA expression of lysozyme is changed during AD progression, we used data from the publicly available database Swe mutations, were investigated using western blot. AβPP‐mutated mice had an increased protein expression of Aβ and of lysozyme as compared to WT mice, which is consistent with the mRNA expression analysis of lysozyme  gmr‐Gal4 driver. The eye morphology was examined at the day of eclosion using SEM. Aβ1‐42 flies had a disturbed pattern of ommatidia compared to control flies  and lysozyme flies   with or without coexpressing human lysozyme in the fly CNS using the elav‐Gal4 driver. As seen in Fig. Arc flies was prolonged from 10 to 11 days for AβArc flies carrying one copy of lysozyme and from 10 to 12 days for AβArc flies carrying two copies of lysozyme. Flies expressing both lysozyme lines reduced the median survival for the control Gal4 expressing flies from 44 days to 41 and 39 days, line A and line B respectively. Next, the velocity and angle of movement were examined using the iFly technique Arc peptide in adult flies, crosses were set up using the lower temperature 18 °C, which has been demonstrated to significantly lower protein expression Arc as well as lysozyme. The velocity of the flies will decrease as they age or get sick. Shortly before the flies die, they become immobile and their velocity cannot be recorded; thus, a cut‐off value of 4 mm·s−1 was set as an indication of dysfunctional locomotor behaviour Arc flies reached below this value after 9 days and after 10 days, no movement could be recorded. For AβArc flies coexpressing one or two copies of lysozyme, the cut‐off value was reached after 12 and 15 days respectively, revealing a dose‐dependent rescue effect of lysozyme on AβArc toxicity where the dysfunctional locomotor behaviour of the AβArc flies was postponed 3 and 6 days . A detrimental effect was also detected in the velocity experiment for lysozyme expressing flies compared to the Gal4 flies, while no general effect of lysozyme was detected in the angle of movement analysis of Gal4 flies. Altogether, these results demonstrate that lysozyme has a protective effect on Aβ‐induced toxicity.The rescue effect of lysozyme on Aβ1‐42 transgenic Drosophila increased the survival of the flies and reduced the levels of Aβ1‐421‐42 between flies that expressed Aβ1‐42 or Aβ1‐42 coexpressed with lysozyme, or AβPP–BACE1 flies and flies with AβPP–BACE1 and lysozyme. The discrepancies between these studies are that in the previous study, Aβ1‐42 and lysozyme were expressed in the CNS but in this study, the expression was targeted to the eyes of the flies. The degradative capacity of Aβ1‐42 in the brain and eye can be different and lysozyme can interact with Aβ1‐42 in another fashion in the brain compared with the eye, which might explain the discrepancies between the results.One possible explanation for the protective action of lysozyme could be that it increases the degradation of the Aβ peptide in the flies. This was shown in a study where coexpression of lysozyme in Aβin vitro that lysozyme binds to monomeric Aβ1‐42 and prevents the formation of toxic Aβ1‐42 species by reducing the aggregation propensity of Aβ1‐421‐40 and Aβ17‐42 by binding during the early stages of fibrillation, thereby reducing toxic species and cytotoxicity Drosophila flies gmr‐Gal4‐derived flies, immunoprecipitation capturing lysozyme was performed on fly head homogenates followed by Meso Scale Discovery, where Aβ was detected with the 6E10 antibody. Indeed, there was a significant increase of Aβ1‐42 in the homogenates from AβPP–BACE1–lysozyme flies compared with the AβPP–BACE1 flies. This demonstrates that also in this Drosophila model lysozyme was able to interact with Aβ and thus likely rescues the degeneration of the ommatidia in the fly eye by preventing the formation of cytotoxic Aβ species.We have previously shown Arc in the fly CNS, only insoluble Aβ species were detected and no significant differences could be observed between the insoluble levels in flies, solely expressing AβArc, and in flies where AβArc was coexpressed with one or two copies of lysozyme. Hence, the protective properties of lysozyme in the longevity and locomotor analyses of the AβArc flies must be unrelated to degradation of AβArc. A possible explanation for the antitoxic effect of lysozyme in the AβArc flies could be due to interactions between the insoluble AβArc species and lysozyme reducing the toxicity of these species. The Arctic mutation causes the Aβ1‐42 peptide to be more aggregation prone and therefore less prone to be degraded. This might explain why lysozyme overexpression in the CNS of AβArc flies was unable to cause an increased degradation of Aβ, which earlier was suggested for lysozyme overexpression in the CNS of Aβ1‐42 flies When quantifying the soluble and insoluble levels of AβDrosophila models of AD. In flies that expressed Aβ1‐42 or AβPP together with BACE1 in the eyes, the rough eye phenotype indicative of toxicity was completely rescued by coexpression of lysozyme. In Drosophila flies that express the toxic AβArc, lysozyme both increased the fly survival dose dependently and decreased dysfunction in locomotor behaviour. We propose that this is due to binding of lysozyme to toxic species of Aβ which prevent these from exerting their toxic effect. Thus, the upregulated of lysozyme expression in AD patients and transgenic AD mice might be a rescue response towards Aβ toxicity. These results highlight the possibility of lysozyme as a potential therapeutic target for AD.In conclusion, we show that the expression of lysozyme was increased in the brains of both transgenic AD mice and humans with AD. Furthermore, we demonstrate favourable effects of lysozyme when expressed in different www.mouseac.org) which includes microarray data from amyloid transgenic mice carrying the AβPPSwe mutation and/or PSEN1 (PSEN1: M146V) either heterozygous or homozygous, and tau transgenic mice (TAU: P301L) GSE64398). In addition, a microarray data set containing information about human mRNA expression was used to study the lysozyme expression in 101 nondemented healthy controls and 129 AD patients (GEO accession number GSE44772) The database ] using a motorized pestle prior to centrifugation at 20 800 g at 4 °C for 1.5 h.Human brain tissue were obtained from the Sydney Brain Bank at Neuroscience Research Australia and the New South Wales Tissue Resource Centre at the University of Sydney and characterized according to established neuropathological criteria ad libitum. In brief, 12‐month‐old APP‐PS1 and age‐matched wild‐type mice were euthanized by CO2 asphyxiation to ensure that the mice did not suffer unnecessarily, and transcardially perfused with ice‐cold phosphate‐buffered saline (PBS). The right hemisphere from the APP‐PS1 and age‐matched wild‐type mice were snap frozen and stored at −80 °C. Cortex was dissected and homogenized in 10 volumes of 140 mm NaCl, 3 mm KCl, 25 mm Tris (pH 7.4), containing 1% Nonidet P‐40 and Roche complete protease inhibitors using a Precellys 24 homogenizer . The supernatants were saved and the protein concentration was determined using a DC protein assay .The APP‐PS1 AD mouse model expressing chimeric mouse/human APP695swe/Swedish mutations (K595N/M596L) and mutant human PS1 (PS1/∆E9) was obtained from the Jackson Laboratory  85Dbo/J; Stock #005864). Animal ethics approval was from the University of Wollongong Animal Ethics Committee (AE11/03). The mice were aged for 12 months without any intervention; food and water were available n = 25), were age‐ and gender‐matched with controls with normal levels of the CSF AD biomarkers P‐tau181P, T‐tau and Aβ1‐42 (n = 25). The samples were provided by the Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital/Mölndal, Sweden. The study was approved by the Ethical committee at the University of Gothenburg. For more information regarding CSF handling and P‐tau181P, T‐tau and Aβ1‐42 analysis, see previously described methods Deidentified and archived CSF samples, that were both biochemically and clinically diagnosed with AD (Protein separation was performed as described previously Swe mice (kindly provided by Professor Lars Nilsson at Oslo University) were housed in a pathogen‐free environment on a 12‐h light/dark cycle. The mice were aged for 15 months without any intervention; food and water were available ad libitum. The experimental procedures were performed in accordance with the Animal Care and Use Ethical Committee at the Linköping University  which follow the directives 2010/63/EU of the European Parliament and of the Council of 22 September 2010 on the protection of animals used for scientific purposes. The mice were euthanized by CO2 asphyxiation to ensure that the mice did not suffer unnecessarily, and transcardially perfused with saline solution  before dissection of the brain. The brain tissue were stored in formalin, dehydrated in sucrose, sectioned and frozen. Immunohistochemistry was performed according to the manufacturer's protocol . Aβ plaques were immunostained using the 6E10 antibody , then colour was developed using diaminobenzidine  and lysozyme was immunostained with an anti‐lysozyme antibody  and colour was developed with Vina Green™ Chromogen Kit . To stop cross‐reaction, the brain slices were incubated with denaturing solution  for 5 min before double staining with lysozyme antibody.C57Bl/6 transgenic AβPPDrosophila melanogaster, the Gal4/UAS system was used gmr‐Gal4 driver strain was used to direct protein expression to the photoreceptors present in the retina of the flies w1118 flies , AβPP695 (AβPP) and BACE1‐expressing flies were purchased from Bloomington stock centre. Signal‐peptide‐Aβ1‐42 flies and signal‐peptide‐AβArc (E22G) were kindly provided by Professor Damian Crowther 1‐42 or AβPP–BACE1 together with lysozyme or flies coexpressing AβArc with either one or two copies of WT lysozyme, cross‐breeds were set up in multiple steps with 12:12 h light:dark cycles and 60% humidity. In the longevity and locomotor analyses, the elav‐Gal4 driver line was used to direct protein expression to the fly CNS. To generate XElav/Y;AβArc/Ife;TM6b/+, a cross was set up using XElav/XElav;CyO/Ife;TM6b/mkrs and X/Y;AβArc/AβArc;+/+. In order to achieve coexpression of AβArc with one or two copies of lysozyme, males generated in the cross previously described were crossed with X/X;LyslineB/LyslineB;+/+ or X/X;LyslineB/LyslineB;LyslineA/TM6b. All gene constructs of lysozyme and AβArc where cloned into the Gal4‐responsive pUAST expression vector to generate UAS‐lysozyme or UAS‐arctic transgene. These constructs were injected into the same background W1118 flies To direct tissue‐specific protein expression in UAS transgenic Cross‐breeds were set up at 25 °C. At the day of eclosion, flies were euthanized with ether before they were mounted onto 12‐mm aluminium specimen stubs with an adhesive tape and air‐dried for 24 h. The samples were sputter coated with 15 nm of platinum and stored in a vacuum desiccator prior to analysis using SEM (JEOL JSM‐6320F). The eyes were scanned at 150× magnification at an accelerating voltage of 10 kV. Images were recorded using the SemA for 5.21 digitizer system (Insinooritoimisto Rimppi Oy). In a blinded set‐up, the images were printed and assigned a square of approximately 100 ommatidia in the centre of the eye. All abnormal ommatidia were quantified within this square and further related to all ommatidia.m Hepes, 5 mm EDTA, protease inhibitor ] for the soluble fraction of Aβ1‐42. After homogenization, the samples were centrifuged for 5 min, 16 000 g. The supernatant was then collected in an Eppendorf tube. The pellet was rehomogenized in 25‐μL insoluble extraction buffer  for the insoluble fraction of Aβ1‐42. After homogenization, the samples were incubated at RT for 10 min, followed by sonication in a water bath for 4 min. The samples were then centrifuged for 10 min, the supernatant of the insoluble fraction was collected and diluted 1 : 10 in Diluent 35 . The samples were stored at −80 °C. To account for differences in the protein extraction step, the total amount of protein extracted was quantified using the Bio‐Rad DC Protein Assay Kit II .Cross‐breeds were set up at 25 °C. Flies were snap frozen in liquid nitrogen at the day of eclosion. Approximately, 20 heads per genotype were homogenized in 120‐μL soluble extraction buffer [50 m1‐42  were blocked using 150‐μL Diluent 35 for 1 h at RT with gentle agitation. After blocking, 50 μL of each prepared protein sample was added to the wells in duplicates . After sample incubation, the wells were washed in 3 × 150 μL PBS‐T before adding 25 μL of the detection antibody  . The wells were then washed again (3 × 150 μL PBS‐T) before adding 150 μL 2× read buffer . The plate was analysed using a SECTOR Imager 2400 instrument .The wells in a multi‐spot 96‐well V‐PLEX human Aβet al. Fly crosses were set up at 18 °C and at the day of eclosion moved to 29 °C where they were aged for 10 days. After ageing, 10 fly heads of each genotype were placed in Eppendorf tubes and stored at –80 °C until use. The Meso Scale Discovery analysis was performed as previously described by Caesar elav‐Gal4 driver were set up at 29 °C and maintained at 29 °C  after eclosion. A set of 100 female offspring for each genotype was collected at the day of eclosion. The flies were then divided into groups of approximately 10 flies and placed in vials containing agar food  and yeast paste (dry baker's yeast mixed with water). Every 2–3 day, the flies were transferred to vials containing fresh food and the number of living flies was counted. This was repeated until all flies had died. Kaplan–Meier survival curves were generated for lifespan assessment.Fly crosses using the Arc‐expressing flies had stopped to move; the Gal4‐ and lysozyme‐expressing flies were analysed every other/third day until no locomotor behaviour could be detected for these fly variants. The videos were processed and analysed using the ifly software Fly crosses were set up at 18 °C and at the day of eclosion, moved to 29 °C. Sets of 30 female flies of each genotype were collected and divided into groups of 10 and placed in vials containing fly food. To analyse the flies’ locomotor behaviour, the flies were filmed during 90 s and tapped to the bottom of the vial every 30 s to reactivate locomotor behaviour. This was carried out every day until all Aβ−1 polyclonal rabbit anti‐human lysozyme . One hundred microlitre of the anti‐lysozyme conjugated medium slurry was placed in a Micro Bio‐Spin Chromatography Column (Bio‐Rad) and the column was equilibrated with SuperBlock TBS Blocking Buffer  supplemented with a protease inhibitor (TBS‐PI). Heads from AβPP flies, AβPP–BACE flies and AβPP–BACE flies with lysozyme were homogenized with a pestle in 200 μL TBS‐PI and centrifuged for 1 min at 16 000 g. One hundred flies of each genotype were used. The supernatant was centrifuged a second time before incubation in the column for 5 min and centrifuged 160 g for 1 min. The resin was then washed four times with TBS‐PI before lysozyme was eluted with 6 m urea. The concentration of Aβ1‐42 was measured using the Meso Scale Discovery technique, as described above.Lysozyme‐specific capture resin was prepared as described earlier graphpad prism software v. 7 . Two‐way ANOVA followed by Tukey's post hoc test was used to test for significant differences between multiple groups of mice. Correlation analysis was performed using the Pearson correlation coefficient. One‐way ANOVA followed by Tukey's test was used for quantification of abnormal ommatidia and to test for differences in protein levels analysed with the Meso Scale Discovery technique. Student's t‐test or Mann–Whitney U test was used to test for significant differences between two groups. For the lifespan assay, Kaplan–Meier survival curves were generated and log‐rank statistical analysis (Mantel–Cox) was performed. Statistical significance was defined for P‐values of < 0.05 (*), < 0.01 (**) and < 0.001 (***).All statistical analyses and graphs were performed and drawn using LS, LB, SN, ACB, KK planned experiments; LS, LB, SN, CK, CJ, LH, HL performed experiments; LS, LB, CK, ACB, KK analysed data; KB, HZ, BG contributed human material; CN contributed mice material; LS, LB, ACB, KK wrote the paper; all authors revised the manuscript critically and approved the final version to be submitted.


However, Li‐CO2 batteries still suffer from unsatisfactory electrochemical performances and their rechargeability is challenged. Here, it is reported that a composite of Ni nanoparticles highly dispersed on N‐doped graphene (Ni‐NG) with 3D porous structure, exhibits a superior discharge capacity of 17 625 mA h g−1, as the air cathode for Li‐CO2 batteries. The batteries with these highly efficient cathodes could sustain 100 cycles at a cutoff capacity of 1000 mA h g−1 with low overpotentials at the current density of 100 mA g−1. Particularly, the Ni‐NG cathodes allow to observe the appearance/disappearance of agglomerated Li2CO3 particles and carbon thin films directly upon discharge/charge processes. In addition, the recycle of CO2 is detected through in situ differential electrochemical mass spectrometry. This is a critical step to verify the electrochemical rechargeability of Li‐CO2 batteries. Also, first‐principles computations further prove that Ni nanoparticles are active sites for the reaction of Li and CO2, which could guide to design more advantageous catalysts for rechargeable Li‐CO2 batteries.Li‐CO In addition, superoxide radicals not only have great influence on the electrolyte but also corrode the carbon specimens easily.2 batteries if the CO2 consumption and evolution were confirmed by in situ measurements during discharge and charge processes.In a typical Li‐CO2 batteries, and relatively decent electrochemical performances were obtained. In a previous report, NiO proved effective in the decomposition of Li2CO3 reported by Li group.2 batteries with excellent electrochemical performances. Especially, the appearance and disappearance of agglomerated Li2CO3 particles and carbon thin films were observed directly in the air cathodes upon the discharge/charge process. Compared with previous results with cathodes prefilled with Li2CO3 and carbon, our results shed new light on the rechargeability of Li‐CO2 batteries.Up to date, only carbon,Figured‐spacing of 2.04 and 1.77 Å  and charge (<4.2 V) platforms at 100 mA g−1  and charge (<4.4 V) platforms with 18 cycles  curves Figure 2a, Ni‐N2CO3, and its decomposition after the subsequent charge process  was utilized to monitor the gas fluent through a Li‐CO2 cell during discharge and charge processes. Figure 2 consumption profile during the discharge process. Here, note that the discharge platform is much lower than that in the above electrochemical tests  spectroscopy . We also used electrochemical impedance spectroscopy (EIS) to characterize the surface states of the electrodes after the first discharge and charge process. The impedance increases apparently after discharge due to the generation of the electrically insulating discharge products, and recovers after the charge process , indicating the excellent electrochemical activity of Ni‐NG. These results confirm the superiority of Ni‐NG cathodes in terms of the reversibility and stability in Li‐CO2 batteries.For the discharged products in the first cycle, X‐ray diffraction (XRD) clearly indicates the formation of the main discharged product of Liss Figure3a. Bes2CO3 and the consumption and evolution of CO2 during the discharge and charge processes were confirmed, the track of the discharge product of C was still a mystery. The direct observation of the discharge product C in working air cathodes is extremely necessary to understand the total electrochemical reactions of Li‐CO2 batteries. First, it is not clear whether the reaction mechanism is the same for Li‐CO2 batteries with noble metal or carbon cathodes. Second, different cathodes showed diverse morphologies of amorphous C. Li‐CO2 batteries with porous gold as air cathodes exhibited the formation of rough and thick amorphous C; in contrast, thin and massive amorphous C generated in platinum net cathodes.Although both the formation and decomposition of Li2 batteries with Ni‐NG cathodes, the morphologies of discharged and charged cathodes were observed through SEM and TEM , we believe that these thin films can be attributed to the newly formed amorphous carbon. Therefore, our Li‐CO2 batteries with Ni‐NG cathodes could indeed generate Li2CO3 and amorphous C according to the reaction of 4Li + 3CO2 → 2Li2CO3+ C.2CO3 prefers to gather together into particles around Ni. More importantly, the unique highly dispersed porous structure with Li2CO3 particles and large film‐like amorphous C ensures uniform electrolyte distribution around the discharge products, and then enhances the decomposition of the products during the charge and results in an improvement in the reversibility.To further elucidate the discharge and charge processes of Li‐COEM Figure4. The 2CO3 , consistent with SAED. Even so, the superior cyclic stability indicates that massive active sites on Ni‐NG could contribute to the homogenous distribution of Li2CO3 and C, and are beneficial to retain the porous structure after electrochemical processes.After the charge process, the discharge products obviously disappear and the cathode recovers to the porous structure with well‐distributed elements . The interactions between the reactants and Ni surfaces including (111) and (200) were computed, and the model is shown in Figure S12 (Supporting Information). The interaction between Li and Ni surface is very strong (−0.99 eV for Li/Ni(111) and −1.19 eV for Li/Ni(200)), suggesting that the Ni surface can effectively adsorb Li. For the adsorption of CO2, after optimization, the CO2 molecule becomes bent due to the strong interaction between CO2 and Ni surface. The adsorption energy is −0.36 eV for CO2/Ni(111) and −0.54 eV for CO2/Ni(200). These results indicate that Ni‐NG can effectively capture the reactants of Li and CO2, and demonstrate that Ni particles are active centers for the reaction between Li and CO2 in Li‐CO2 batteries.First‐principles computations were further performed to confirm the superiority of Ni‐NG in Li‐CO2 batteries with Ni‐NG cathodes delivered high discharge capacity and excellent cyclic stability with stable discharge and charge platforms. Meanwhile, the reversible consumption and evolution of CO2 were confirmed by DEMS. More importantly, the unique morphology of Ni‐NG cathodes enabled SEM, TEM, and SAED observations of the morphological evolution of the discharge products of agglomerated Li2CO3 particles and carbon thin films. Therefore, the reversibility of the electrochemical reaction could well be understood in Li‐CO2 batteries, and this work would inspire more strategies for developing highly efficient cathodes for rechargeable Li‐CO2 batteries.In conclusion, we fabricated a composite of Ni nanoparticles highly dispersed on N‐doped graphene with 3D porous structure. Li‐COMaterials Preparation: All the reagents were analytical grade without further purification. Few‐layered graphene was purchased from J&K. In a typical synthesis process, 0.349 g Ni(CH3COO)2∙4H2O, 17.5 mg graphene, and 1.394 g urea were mixed with 35 mL ethylene glycol (EG) through intense agitation for 0.5 h, and ultrasonically treated for 0.5 h homogeneously. Next, the mixed solution was transferred into 50 mL Teflon‐lined stainless steel autoclave and kept at 200 °C for 1 h. After cooling down, the mixture was washed with ethanol for six times, and dried at 80 °C in a vacuum oven. The Ni‐NG composite was obtained by annealing the above mixture at 700 °C in an Ar atmosphere for 10 h.Materials Characterization: XRD was performed on a D/MAX III diffractometer with Cu Kα radiation. Field emission SEM (FESEM) images were obtained on a JEOL‐JSM7500 microscope. TEM and HRTEM images were taken on FEITecnai G2F‐20, and XPS was performed on Axis Ultra DLD . FTIR spectroscopy was conducted on NicoletMAGNA‐560 FTIR spectrometer by using KBr pellets, and Raman spectra on a Renishaw inVia Raman spectrometer equipped with a 632.8 nm laser. TG‐DTA was performed on Rigaku PTC‐10 A TG‐DTA analyzer, and Vario EL CUBE elemental analyzer was used to quantitatively confirm the contents of C and N. 1H NMR was recorded on a Bruker AV400 spectrometer. DEMS was measured through a commercial quadrupole mass spectrometer  and a home‐made Swagelok‐type DEMS cell with two PEEK capillary tubes as purge gas inlet and outlet. The details can be found in a previous report.Electrochemical Tests: The electrochemical behaviors were measured in Swagelok cells with a 1.0 cm2 hole placed on the cathode which enabled CO2 to flow in. The cells were assembled in a glove box filled with high‐purity argon (O2 and H2O < 0.1 ppm). For the cathode preparation, a slurry, obtained by mixing Ni‐NG and polyvinylidenefluoride (PVDF) with the mass ratio of 9:1, was uniformly deposited on a circular piece of carbon paper , and then dried in an oven at 80 °C. Li foil (14 mm) was used as the anode, and polytetrafluoroethylene (PTFE) membrane (18 mm) as the separator. The electrolyte was 1 mol L−1 lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) dissolved in tetraethylene glycol dimethyl ether (TEGDME). Discharge/charge tests were conducted on LAND‐CT2001A testers, and the cells were discharged to 2.2 V and then recharged to 4.5 V. CV and EIS were conducted on a Zahner‐Elektrik IM6e electrochemical workstation within 2–4.5 V. Cyclic tests were controlled with the cutoff capacity of 1000 mA h g−1 at a current density of 100 and 200 mA g−1, that is, the cells were discharged and charged for 10 and 5 h, respectively.Computational Methods: First‐principles computations on basis of density functional theory (DFT) were performed with a plane‐wave technique as implemented in the Vienna Ab initio simulation package (VASP).k‐point meshes of 11 × 5 × 1 for Ni(111) and 11 × 5 × 1 for Ni(200). The model is shown in Figure S12 (Supporting Information). Considering weak interactions, the DFT‐D3 method with Beck–Jonson damping was adopted.c‐axis, a vacuum space with ≈20 Å was inserted. In the computations, the lower three layer atoms were fixed and other atoms were fully relaxed. The adsorption energy (Eads) of adsorbates was calculated from the equation Eads = Etot − EM − EN, where Etot, EM, and EN represent the total energy of the complex of the Ni substrate and adsorbate, the isolated atom/molecule, and the Ni substrate, respectively.The authors declare no conflict of interest.SupplementaryClick here for additional data file.