GC1 rational cubic Ball curve with three free parameters, later the 2D contours are flipped into 3D with equidistant z component. The constructed surface is represented by contours blending interpolant. At the end of this manuscript a case report of parietal bone fracture is also illustrated by employing this method with a Graphical User Interface (GUI) illustration.Maxillofacial trauma are common, secondary to road traffic accident, sports injury, falls and require sophisticated radiological imaging to precisely diagnose. A direct surgical reconstruction is complex and require clinical expertise. Bio-modelling helps in reconstructing surface model from 2D contours. In this manuscript we have constructed the 3D surface using 2D Computerized Tomography (CT) scan contours. The fracture part of the cranial vault are reconstructed using  Craniofacial region is a complex anatomical part made up of various bones joined together. The methods used for the construction of fracture segment are either anatomical or mathematical features. The mirroring method is useful for the fracture on one side of the skull only and use anatomical features. While mathematical constraints are used in interpolation and deformation methods to construct the fractured part from the non fractured part of skull. Reference model is also used to construct the fractured part of skull . For morGC1) rational cubic Ball curves with three free parameters. Genetic Algorithm (GA) is used to optimize the free parameters. Then, we converted the 2D contour curves in 3D form by taking equidistant z component and then construct the 3D parietal bone fracture.Contours blending function have been used to construct the 3D parietal bone fracture. Since Digital Imaging and Communications in Medicine (DICOM) data used in our work are in 2D form, so, before constructing the 3D surface, firstly, we have constructed fracture part curves using geometric continuity . We employed matlab for both the programming and to develop Graphical User Interface (GUI) for parietal bone fracture reconstruction using proposed algorithm. Surgeons can use GUI for fracture reconstruction without having in depth knowledge of its mathematical aspect.The introduction is followed by the representation of Ball basis functions and rational cubic Ball curve. It is followed by an explanation on contour blending, boundary extraction, parametrization, Normalized mean squares error. After this, we have explained the Graphical User Interface (GUI). An algorithm on 3D parietal bone fracture reconstruction using rational Ball curve and contour blending is proposed after the explanation of GUI.θ. The Ball basis functions can be written asThe cubic Ball polynomial basis was first proposed by Ball  for CAD Theorem 1: The Ball basis functions defined in a0, …, a3, for which.Linearly Independent: The Ball basis functions are linearly independent. There do not exist set of non zero constants θ ∈ .Non Negative: Ball basis functions are non negative when Symmetric: The Ball basis functions are symmetric asS0(θ) is monotonically decreasing and S3(θ) is monotonically increasing when θ ∈ .Monotonicity: Partition of Unity: Ball basis functions form a partition of unity, it means that sum of Ball basis functions will be 1.Theorem 2: Let Pi be the set of control points and Si(θ), i = 0, …, 3 are Ball basis functions defined in Coordinate system independence: As the Ball basis functions form partition of unity, so the Ball basis curve will be coordinate system independence. It means that by changing the coordinate system of control points curve will remain same.Convex Hull Property: As the Ball curve obeys the coordinate system independence and Ball basis functions are all non negative. So Ball curves will obey the convex hull property. It means that curves formed by Ball basis always lie within the convex hull of their control points.b number of points and control polygon by p number of points, then it will always hold thatk is 0 or a positive integer.Variation Diminishing Property (VDP): Variation Dimension Property is obeyed by Ball curves. VDP is stated as if a curve is intercepted by straight line in Endpoint Interpolation: The Ball curves always passes through the first and last control points.Theorem 3: Let Pi be the set of control points and Si(θ), i = 0, …, 3 are Ball basis functions defined in P1 = P2.The cubic Ball curve reduce to quadratic curve if The Ball curve passed away from the convex hull intermediate control points as compared to the Bezier curve as shown in Operation of degree elevation and reduction for a polynomial curve with Ball basis functions are simpler and faster than the curve with Bezier basis functions .s(θ) defined in [GC1 continuity consider the two consecutive curve segmentsfi, fi + 1, fi + 2i = 1, …, n − 1 are the on curve control points and ai, bi and λi are free parameters. For curve fitting, firstly, we will find off curve control points using least square method. Then, free parameters will be optimized with the help of genetic algorithm.The cubic rational Ball curve fined in , 27 issC1 while in current work the continuity between two curve segments is geometric continuity GC1 as the geometric continuity is more flexible than parametric. We have used C1 rational Ball curves with tangents at end points. The tangent vectors work as intermediate control points, while in current work we are using GC1 rational Ball curves and the intermediate control points are evaluated using least square method. In the current work the number of free parameters is increased to three and the proposed method is more flexible due to its geometric continuity. The proposed method works well for both small and large fractured parts. In current work we have extended the 2D CT scan data into 3D format taking equidistant z-component to construct the 3D craniofacial fractured part.In  the contEffect of Control Point and Free ParametersP1 control point the curve bend toward P1. Similarly, with P2 control point keeping the free parameters unchanged. Secondly, by changing the free parameter a and keeping b constant. For example in P1. Likewise, by changing b the curve will bend toward P2.Ball curve can be changed or controlled by twofold. Firstly, by changing the off curve control points. For example in D form. To construct the surface, patch one have to convert the data in 3D form. For this, we took the non decreasing z component of each 2D contours as a height like z0 < z1 < … < zmax. The ith contour is defined by the sequence of distinct data points which are counterclockwise ordered in the contour at the height zi.The given Dicom data are in 2D contour have been constructed using proposed interpolant, and is converted into 3D form taking equidistant z component [Ci − 1(ψ), Ci(ψ) and Ci + 1(ψ) are missing part curves at height zi − 1, zi and zi + 1 respectively. The cubic Ball interpolant can be written asi = 1, …, n − 1, 0 ≤ θ, ψ ≤ 1,The fracture part curves for each 2omponent . Let Ci n represents the number of contours. Sj, j = 0, …, 3. are Ball basis polynomial functions defined in where vi(ψ) is a tangent to surface at (Ci(ψ), zi), to define the tangent vector letPi(ψ) = (Ci(ψ), zi) for i = 1, …, n. Where Pi(ψ) is in 3D form because Ci(ψ) is in 2D form. LetPi(ψ) − Pi − 1(ψ)) and (Pi + 1(ψ) − Pi(ψ)). The z − component of Ci + 1(ψ) − Ci(ψ)|(zi − zi − 1) + |Ci(ψ) − Ci − 1(ψ)|(zi + 1 − zi). Let Vi(ψ) be the vector product when z − component.|Vi(ψ) = (vi(ψ), 1) whereD1 = Ci + 1(ψ) − Ci(ψ) and D2 = Ci(ψ) − Ci − 1(ψ).Then Vi(ψ) will be chosen to be a tangent to the surface at Pi(ψ). If Ci + 1(ψ) = Ci(ψ) = Ci − 1(ψ), then D1 = D2 = 0 and vi(ψ) is set to be .The vector vi(ψ) lies in a plane containing Pi + 1(ψ), Pi(ψ) and Pi − 1(ψ). If these points lie in a vertical plane, thenv*(ψ) and some scalers λ and μ. Thenλμ < 0, then |μ|λ = −|λ|μ and vi(ψ) = 0.As λμ > 0, thenzi + 1 − zi)(zi − zi − 1),vi(ψ) is proposed by [If posed by  for a cozi and zi + 1 is given by,z1 and zn isFinally the surface between two consecutive contour β(A) = A − (AΘB). In this equation A represents the set of all black pixels, B represents 3 × 3 structured elements, β(A) is the boundary set of A, − and Θ represents the difference and erosion operator. To divide the boundary in smaller segments, we use the corner points. Sarfarz et al method [To construct the parietal bone fracture, we will initially determined the boundary of each CT scan image using mathematical morphology. The mathematical morphology is defined as l method  is emploθi corresponding to Di, where Di represents the data points of each segments.This manuscript employs the chord length parametrization to find the values of Di are the data points of each segments and θ is parameterized by chord length. We will find the free parameters ai, biandλi in proposed interpolant by minimizing the cost function. Genetic Algorithm (GA) defined in [ai, biandλi respectively.fined in  is used GUI consists of one or more windows having control, these are called components. GUI is utilized to perform the interactive tasks and display it graphically. GUI facilitates the users in completion of different tasks. Users are not required to learn the basic programming of each component. GUI consist of start and stop button, panel, scroll bar, push button and boxes etc.GUI with its individual controls has a executable MATLAB code known as callbacks. The implementation of each callback is activated by a particular user action such as clicking a mouse button, pressing a screen button, typing a string or a numeric value, selecting a menu item, or passing the cursor over to a component. The GUI then reacts to these events. In this manuscript, GUI is used to construct and control the curves of the fractured segment of the parietal bone. The input for curve construction is missing part end points.This section simplifies the algorithm for craniofacial fracture reconstruction.Input: CT scan image in Dicom format.Output: Constructed 3D craniofacial fracture.Read image as in Boundary extraction Fig 8(c)Corner points detection to make segments of curve Fig 8(d)GC1 rational Ball curve is used to fit each segment. The unknown parameters ai, bi and λi in Fig 8(d)Step 4 is repeated until a desired solution is obtainedFracture part curves reconstruction for each CT scan slice as in Figs 10Using GUI for the construction of curves as in Fig 11Conversion of 2D CT scan data into 3D form as in Fig 12Construction of 3D craniofacial fracture using proposed method as in Figs −2 for the desired solution. In In step 4 we reconstruct the boundary curve of a full skull using our proposed method. The genetic algorithm (GA) is used to optimize the free parameters. Normalized mean squares error is used as a cost function in GA and will be repeated until we get the best possible values of free parameters for boundary curve construction as shown in GC1 continuity at each knot as shown in z component as shown in This section illustrates an example of application of the proposed algorithm. The given 2D CT scan Dicom data are in slices as in The Human Research Ethics Committee, Universiti Sains Malaysia, approved the study. Data were collected from archived images of patients from the Picture Archiving and Communication System (PACS) server at the Radiology Department, Hospital Universiti Sains Malaysia. The patients had undergone decompressive craniectomy surgery between May 2009 and December 2014 at the Hospital Universiti Sains Malaysia, Kubang Kerian, Kelantan Malaysia. The medical images were anonymized and the researchers had no access to patients’ information.GC1 rational Ball curves, since the given Dicom data are in 2D form. Then we convert each 2D contour into 3D form taking equidistant z component. The free parameters in proposed interpolant are optimized using Genetic Algorithm. The proposed method will provide the custom made implant for every individual patient. It is also time saving as the surgeon can perform the task of designing the implant geometry without the help of technicians and any other external help. It also reduces the incidence of infection. Proposed method is user friendly due to the presence of GUI.Contours blending function have been used to construct the 3D surface. A patient with parietal bone fracture have been discussed as a case study to show its applicability. Fracture part curves of each contour is constructed in 2D form using


We have recently shown that T-antigen binding to Site I results in the replication-dependent introduction of H3K9me1 into SV40 chromatin late in infection. Since H3K9me2 and H3K9me3 are also present late in infection, we determined whether their presence was also related to the status of ongoing transcription and replication. Transcription was either inhibited with 5,6-dichloro-1-beta-D-ribofuranosylbenzimidizole (DRB) or stimulated with sodium butyrate and the effects on histone modifications early and late in infection determined. The role of DNA replication was determined by concomitant inhibition of replication with aphidicolin.We observed that H3K9me2/me3 was specifically introduced when transcription was inhibited during active replication. The introduction of H3K9me2/me3 that occurred when transcription was inhibited was partially blocked when replication was also inhibited. The introduction of H3K9me2/me3 did not require the presence of H3K9me1 since similar results were obtained with the mutant cs1085 whose chromatin contains very little H3K9me1.Our data suggest that methylation of H3K9 can occur either as a consequence of a specific repressive event such as T-antigen binding to Site I or as a result of a general repression of transcription in the presence of active replication. The results suggest that the nonproductive generation of transcription complexes as occurs following DRB treatment may be recognized by a ‘proof reading’ mechanism, which leads to the specific introduction of H3K9me2 and H3K9me3. Five distinct but potentially related elements are thought to contribute to the epigenetic regulation of eukaryotic gene expression: DNA methylation, nucleosome location, histone variation, covalent histone modifications, and interactions by regulatory RNA. Of these elements, the post-translational modification of histones has been of particular interest because of the diversity of the available forms of modification and the number of target amino acids and their physical location within histones. Importantly, there is an abundance of published reports demonstrating the association between certain forms of histone modification and activation or repression of transcription in one or more well characterized biological systems.In general, it is thought that acetylation of certain lysines in histones is associated with active biological processes like transcription while methylation of lysines or arginines may be associated with either activation or repression of gene transcription. For example, in the nucleosome core, histone H3 acetylation on lysine 9 and 14 (H3K9 and H3K14) have been shown to be associated with transcription along with methylation of lysine 4 (H3K4), while methylation of lysine 9 (H3K9) has been shown to be associated with repression.While the association between the methylation of H3K9 and gene repression has been well established, much less is known about the circumstances that lead to the introduction of methylated H3K9 into chromatin. What has added to this uncertainty is the complexity of methylation, including mono-, di-, and tri-methylation, and the involvement of multiple methylating enzymes[In order to better understand the factors that contribute to epigenetic regulation, we have been investigating the role of histone modifications in the regulation of gene expression during the Simian Virus 40 (SV40) life cycle. In a reDuring the course of these studies, we investigated the introduction of all three methylated forms of H3K9 during replication. We noted that unlike the introduction of H3K9me1 which absolutely required replication, the introduction of H3K9me2 and H3K9me3 appeared to occur even when replication was substantially blocked by inhibitor. These rIn order to address these questions in SV40 chromatin, we have investigated the effects of a general inhibition or stimulation of transcription on the introduction of H3K9 methylation in the presence or absence of active replication. Transcription was inhibited with 5,6-dichloro-1-beta-D-ribofuranosylbenzimidizole (DRB), a well-Since we previously observed that the introduction of H3K9me2 and H3K9me3 was not directly related to repression by T-antigen binding to Site I, we hypoSV40 minichromosomes were isolated and purified from cells infected with wild-type 776 virus following treatment with DRB or no treatment. When minichromosomes were isolated at 2 hours, cells were pretreated with DRB for 2 hours prior to infection, while for minichromosomes isolated at 48 hours post-infection infected cells were treated from 24 to 48 hours. In these experiments, we observed a 112 ± 35 fold increase in the size of the pool of SV40 chromosomes present in glycerol gradient fractions following purification from cells infected for 48 hours compared to 24 hours post-infection. While the increase was somewhat variable we always observed at least a tenfold increase. This increase was reduced 10 ± 6 fold following treatment of the SV40 infected cells with DRB from 24 to 48 hours post-infection. The latter analysis was determined by comparing the increase in the presence and absence of inhibitor and indicates that on average there was about a tenfold reduction in the pool of SV40 minichromosomes following inhibition. As expected, treatment with DRB substantially inhibited the generation of mRNA (data not shown).The effect of DRB on the introduction of methylated H3K4 and H3K9 was determined by subjecting treated and untreated samples of intact SV40 minichromosomes obtained at 2 hours and 48 hours post-infection to ChIP analyses with antibodies that recognize mono-, di-, or tri-methylated H3K4 or H3K9. Intact SV40 minichromosomes were used because they are easily obtained in relatively large amounts and yield the maximum PCR signal compared to fragmented chromatin. Because the SV40 genome was intact, this analysis only yielded information relative to changes in the numbers of minichromosomes carrying a particular modification following treatment. No information was obtained concerning the location of any specific histone modifications. The results of these analyses are graphically shown in Figure Since we have previously shown that the introduction of H3K9me2 and H3K9me3 into SV40 chromatin late in infection does not require DNA replication, we nextSince H3K9me1 can be present in as much as 22% of the SV40 minichromosomes present at late times[In order to determine whether H3K9me2 and H3K9me3 were being added to minichromosomes that contain RNAPII following treatment with DRB, we analyzed SV40 minichromosomes that contain RNAPII for the presence of the two methylated forms of H3K9 following treatment with DRB using our ISFIP procedure. In thisSince the introduction of H3K9me2 and H3K9me3 appeared to be associated with repression of transcription, we then determined whether stimulation of transcription would have the opposite effect. Sodium butyrate is a well-known inhibitor of many histone deacetylases and for this reason has been used extensively to investigate the relationship between histone acetylation and various biological processes including transcription, 12. We SV40 wild-type infected cells were harvested at 24 hours post-infection, 48 hours post-infection, or 48 hours post-infection following treatment with 50 μM sodium butyrate from 24 to 48 hours post-infection to determine the effects of sodium butyrate during the period of active replication. In a parallel analysis, infected cells were harvested at 12 hours post-infection and 12 hours following a 12-hour treatment with sodium butyrate to determine the effects of sodium butyrate in the absence of replication. The minichromosomes were purified and subjected to ChIP analyses with antibodies to methylated H3K4 and H3K9 with minichromosomes isolated late in infection but only methylated H3K9 when isolated at very early times. The reason for this was our previous observation that relatively little of the SV40 chromatin contained methylated H3K4 at the very early times[Since DRB had a major effect on transcription and the introduction of H3K9me2 and H3K9me3, we also determined whether it affected the proportion of minichromosomes carrying RNAPII and was, therefore, potentially capable of transcription. We have previously shown that with short-term treatment with DRB there was little effect on the percentage of minichromosomes carrying RNAPII. HoweverAs indicated above, between 24 and 48 hours post-infection we observed a 112 ± 35 fold increase in the size of the minichromosome pool. Following treatment with aphidicolin the pool size at 48 hours post-infection was essentially the same as at 24 hours post-infection indicating substantial inhibition by the drug. Following treatment with DRB we again observed a substantial increase in the pool of minichromosomes although the increase was 10 ± 6 fold less than observed in the absence of the inhibitor. Treatment with sodium butyrate was seen to increase the size of the pool of minichromosomes by 10 ± 4 fold above the level of increase without the added sodium butyrate. The latter two results indicate that the inhibitors had a modest effect on pool sizes when replication was occurring.SV40 minichromosomes from treated or untreated infections were subjected to ChIP analysis with antibody to RNAPII with the results shown in Figure The introduction of H3K9me2 and H3K9me3 into SV40 chromatin following repression of transcription through the inhibition of RNAPII elongation by the inhibitor DRB is consistent with previous reports showing that the presence of H3K9me2 and H3K9me3 in chromatin is associated with transcriptional repression . H3H3K9me2 and H3K9me3 are typically introduced into chromatin by a member of the SET domain family of histone methyltransferases. The relThere are two well-characterized mechanisms for the introduction of H3K9me2 and H3K9me3. H3K9me2 is associated with repression of nuclear hormone receptor regulated transcription (reviewed in). In thiThe introduction of H3K9me3 into heterochromatin has also been extensively characterized (reviewed in). The inIt seems unlikely that either of these mechanisms is responsible for the introduction of H3K9me2 and H3K9me3 reported here. With respect to the introduction of H3K9me2, SV40 transcription does not appear to be regulated by a nuclear hormone type mechanism as previously described for H3K9me2. Similarly the observed increase in H3K9me2 occurred as a consequence of the inhibition of transcription by DRB not the binding of normal transcription factors. The introduction of H3K9me3 also is unlikely to occur by the same mechanism as described for heterochromatin. Notably, SV40 DNA in chromatin is not known to be methylated because of an absence of DNA methylase substrates in the DNA. Also our observed increase in H3K9me2 and H3K9me3 appeared to be only secondarily a result of DNA replication since the increase was observed on minichromosomes containing RNAPII.To explain our results we propose the following model. As DNA replication takes place, some of the newly replicated minichromosomes are committed to transcription through the binding of specific and general transcription factors. Concurrently, for reasons as yet unknown, some of the preexisting transcribing minichromosomes stop transcription. These nonfunctioning minichromosomes are recognized as being repressed, and H3K9me2 and H3K9me3 are introduced into their chromatin as a mark of repression. We propose that following replication and the activation for new transcription there is a ‘proofreading mechanism,’ which ensures that the newly initiated minichromosomes are capable of productive transcription. In the event that this is not the case, the minichromosomes are again recognized as repressed, as with the nonfunctioning minichromosomes, and marked by H3K9me2 and H3K9me3. Since treatment with the inhibitor DRB results in a large increase in the number of minichromosomes in which transcription is stopped, presumably at initiation, there is a corresponding increase in the incorporation of H3K9me2 and H3K9me3.This proofreading mechanism could be specific to SV40 and other similar viruses in which case it could function to ensure that the size of the pool of transcribing minichromosomes is tied to the level of replication and encapsidation. Conversely, this mechanism could be true for higher eukaryotes in general and serve as a way to ensure that when genes are activated for transcription, only those genes correctly activated are allowed to persist in the activated state.Assuming that the introduction of H3K9me2 and H3K9me3 following the inhibition of elongation by RNAPII reflects a normal biological process for SV40, we believe it is likely to play a role in two aspects of normal SV40 molecular biology. First, the introduction of H3K9me2 and H3K9me3 could play a critical role in regulating the pool size of transcriptionally competent minichromosomes during an infection. We have presented evidence that the pool size is dynamic with new transcribing minichromosomes entering the pool as a result of replication and old minichromosomes leaving the pool. We believe that old minichromosomes leaving the pool of transcribing minichromosomes would be labeled with H3K9me2 and H3K9me3 in order to prevent their reactivation.Second, H3K9me2 and H3K9me3 could also play a critical role during the initiation of a subsequent infection. We have shown that minichromosomes in virions contain significant amounts of H3K9me2/3[in vivo.Because DRB treatment blocks RNAPII elongation, we believe that it is a way to model the effects of repression of transcription in order to characterize the subsequent changes in epigenetic modifications. However, we recognize that the DRB treatment, as well as the treatment with the other inhibitors themselves, may be responsible for the observed effects on the levels of H3K9me2 and H3K9me3 and may not accurately reflect the epigenetic changes occurring Methylation of H3K9 can occur during active expression either as a consequence of a specific repressive event such as T-antigen binding to Site I or as a result of a general repression of transcription. Moreover, these results suggest that the nonproductive transcription complexes which are generated by DRB treatment may be recognized by a ‘proof reading’ mechanism, which leads to the specific introduction of H3K9me2 and H3K9me3.Wild-type and mutant SV40 minichromosomes were prepared in the monkey kidney BSC-1 cell line (ATCC) using either wild-type 776 virus (from Dr. Daniel Nathans) or cs1085 virus (from Dr. Daniel Nathans).BSC-1 cells were maintained and infected as previously described–7. An RNSV40 minichromosomes were isolated at the indicated times from 2 hours to 48 hours post-infection as described for each of the analyses using our standard purification protocols–7 with oChIP kits were obtained from Millipore  and the protocol was followed as previously described. The antChIPs were performed as previously described–7 with tPreparation of DNA: Samples were prepared for PCR using an MP Bioscience  Geneclean Spin Kit (#111101-200) with the following modifications. The glassmilk reagent (100 μl) was mixed with 50 μl of sample in a 1.5-ml centrifuge tube. The tube was mixed by repeated inversion at 2 minutes and again at 4 minutes of incubation. Following 5 minutes of room temperature incubation, the samples were centrifuged at 6,000 rpm for 30 seconds in a Micro One (Tomy) to pellet the glass. The supernatant was discarded and 200 μl of the wash buffer was added to the tube. As the wash buffer was being added, the pipette tip was used to break up the pellet by physically rubbing the pellet and vigorously pipetting up and down. The samples were inverted twice and centrifuged at 6,000 rpm for 30 seconds to again pellet the glass. The supernatant was discarded and the pellets were dried in a vacuum for 5 minutes. The glass pellet with bound DNA was resuspended in 25 μl Tris EDTA (TE) buffer.For most of the amplifications, DNA was amplified from the promoter region of the SV40 genome using the primers 5′ TTG CAA AAG CCT CCA AA 3′ and 5′ TGA CCT ACG AAC CTT AAC CGA GGG 3′ in a CFX Connect Real Time System thermal cycler  using ‘SSO Advanced DNA polymerase . In the immune selection fragmentation experiment, DNA was amplified from the early region using the primers 5′TGCTCCCATTCATCAGTTCC3′ and 5′CTGACTTTGGAGGCTTCTGG3′ because the promoter region is extremely sensitive to sonication. Immediately before use, the primers and DNAse free water were added, and 28 μl of the mix was used per sample. 2 μl of the resuspended glass milk in TE buffer was added per sample. Samples were amplified by PCR in triplicate with a melt curve applied afterwards to ensure specific amplification. All sample preparation for PCR was done in either a Nuaire biological safety cabinet Model NU_425-400 or an AirClean 600 PCR Workstation (ISC BioExpress).This research did not involve the use of any human subjects, materials, or data.


The thermal conductivity is investigated by the MD simulation and Clarke’s model. This can improve the understanding of the microstructure and thermodynamic properties of (DyY)Zr2O7 (DYZ) at the atomistic level. The phonon-defect scattering and phonon-phonon scattering processes are investigated via the theoretical calculation, which provides an effective way to study thermal transport properties of ionic oxides. The measured and predicted thermal conductivity of DYZ is lower than that of 4 mol % Y2O3 stabilized ZrO2 (4YSZ). It is discovered that DYZ is thermochemically compatible with Al2O3 at 1300 °C, whereas at 1350 °C DYZ reacts with Al2O3 forming a small amount of new phases.Ceramic oxides that have high-temperature capabilities can be deposited on the superalloy components in aero engines and diesel engines to advance engine efficiency and reduce fuel consumption. This paper aims to study doping effects of Dy It is reported that Dy-YSZ is composed of the cubic/tetragonal structure at lower doping level, and the thermal conductivity decreases with the addition of Dy2O3 and Y2O3 to ZrO2Various ceramic materials are developed to satisfy the requirements of new TBCs including low thermal conductivity, high coefficient of thermal expansion (CTE), thermochemical stability, and sintering resistance5MD simulation can be performed to systematically predict the theoretical material properties of various chemical compositions2 with Dy3+ which has a higher atomic weight and larger ionic radius than Zr4+ can potentially modify the thermal conductivity. The relationship between chemical composition, microstructure and thermal conductivity is studied. The phonon scattering processes which significantly influence the thermal conductivity are highlighted by the theoretical calculation based on the MD model and Clarke’s model. We have investigated the thermochemical compatibility of DYZ with Al2O3 by the structural characterization and the local chemical environment study of powder mixtures. This present work improves the understanding of the microstructure and thermodynamic properties DYZ on the atomistic level.There is limited information on the thermodynamic properties of DYZ, while no reports exist on the MD simulation of DYZ. This paper emphasizes the development of novel ionic oxide materials via experiment and theoretical calculation. Doping ZrO3+ and Dy3+, 1-propanol, zirconium propoxide in 1-propanol and acetylacetone. These precursors were mixed to form a solution with the desired molar ratio under argon atmosphere to prevent the fast hydrolysis of Zr(OPr)4 with H2O. The molar ratio: [AcAc]/[Zr(OPr)4] = 0.7. The concentration of Zr(OPr)4 was 0.5 mol/L. Deionized water was added to the 1-propanol to achieve the concentration of 10 mol/L. The water in 1-propanol was mixed with the Zr(OPr)4 solution with the molar ratio [H2O]/[Zr(OPr)4] = 8.5. The mixed solution was stirred mechanically for 30 min. The homogeneous sol was dried at 50 °C for several hours to obtain the gel, followed by calcination at 950 °C for 3 hours to obtain ceramic powders. The as-sintered powders were treated at 1200 °C for 2 hours, followed by uniaxial compaction of the powders into pellets. The pellets were sintered at 1200 °C for 6 hours.The starting materials consist of metal salts of Y2O3 was studied using a solid-state reaction method. The as-synthesized powders were mixed with Al2O3 in an equal mass ratio, followed by ball milling for 8 hours. The ball milled powders were sintered at 1300 °C and 1350 °C under air atmosphere to study the thermochemical compatibility.The thermodynamic stability between the as-synthesized DYZ powders and Alλ = 1.54 Å). Raman analysis was conducted via a Horiba Jobin-Yvon LabRAM spectrometer equipped with an Olympus BX41 microscope . The surface morphology and microstructure of the particle and pellets were examined by a Phillips XL30 scanning electron microscope (SEM). The surface chemical analysis was carried out via a Thermo Scientific K-Alpha X-ray photoelectron spectrometer (XPS) using a monochromated Al-Kα X-ray source (hν = 1486.6 eV). The thermal conductivity of the pellets was measured using a thermal conductivity analyser (C-Therm TCi) at room temperature. The coefficient of thermal expansion is measured using a TA Q400 Thermomechanical Analyser (TMA) from room temperature to 900 °C under a N2 atmosphere with a heating rate of 5 °C/min. The bulk density (ρ) was determined by measuring the weight (w) and the volume (v) of the pellet directly, where ρ = w/v. The theoretical density was estimated via the lattice parameters from XRD, and the molecular weight was calculated based on each molecular formula. The bulk thermal conductivity was calculated based on the porosity and the measured thermal conductivity using,The crystal structure was characterized via X-ray diffraction (XRD) using a Siemens D500 X-ray diffractometer -ensemble for the system to reach equilibrium and an -ensemble for the calculation of thermodynamic properties. In the initial -ensemble, in which the temperature, pressure and number of particles are constant, the atoms reach equilibrium during a period of 5 × 104−10 × 104 time steps (25–50 ps). In the -ensemble, which is referred to as the system with a constant volume, constant energy and constant number of particles, a temperature perturbation is generated within the simulation cell along the long dimension of the simulation cell during a period of 2.5 × 105 time steps (125 ps). The potential is determined via Buckingham potential for the short-range interaction between ions and the long-range Coulomb interaction.The simulation is conducted based on the rigid-ion model. The simulation cell contains 6 × 6 × 32 crystallographic unit cells, and thermal conductivity is calculated via the non-equilibrium MD simulation methodAij, ρij and Cij are Buckingham potential parameters which consist of the Born-Mayer potential, Aij indicates the repulsion between two ions when their electronic clouds overlap. ρij is the ionic radii of two ions, and Cij represents the strength of the van der Waals interaction of two ions. Qi, Qj and rij describe the Coulomb interaction. Qi and Qj are the charges of two ions, rij is the separation of two ions and ε0 is the vacuum permittivity222426where εIn the non-equilibrium MD model, the heat is incorporated into a slab of materials and removed from another slab of materials, as shown in ε is the kinetic energy, Δt is the MD time step (0.5 fs), and A is the cross-sectional areawhere Δκ is the thermal conductivity, Jz is the heat currentwhere 2 influences the particle sizes: higher rare earth content tends to form smaller particles due to the fact that the rare earth atoms can increase particle brittlenessThe surface morphology of as-synthesized powders and pellets was characterized via SEM , in ordeThe phase composition was measured by XRD, as presented in The crystal size of the as-sintered powders was calculated based on line broadening using the Scherrer equation,D is the dimension of crystalline, λ is the wavelength (Cu-Kα), θ is the diffraction angle, K is the constant where Bp(2θ) is the true half maximum width, Bh(2θ) is the measured half maximum width of the sample and Bf(2θ) the standard half maximum width6 300. With the increase in the concentration of Dy2O3 and Y2O3, the average crystallite size decreases  is in strong agreement with the experimental data (6.4093 g/cm3). Hence, the potential parameters are sufficient to generate correct lattice structure of -ZrO2 in the simulation. The density of DYZ and 4YSZ from 295 K to 1874 K is presented in The thermal conductivity of DYZ and 4YSZ has been calculated via MD simulation in order to investigate the intrinsic property of the perfect lattice from room temperature to high temperatures. The reduction of thermal conductivity can be achieved by creating a novel composition such as a solid solution because dopants and the corresponding oxygen vacancies can reduce the intrinsic thermal conductivity via scattering lattice waves3+ cations into the ZrO2 lattice creates one oxygen vacancy in order to maintain the charge neutrality. This oxygen vacancy, the mass difference, and the ionic radii difference between Dy3+ and Zr4+, Y3+ and Zr4+ decrease the phonon mean free path and thermal conductivityThe calculated thermal conductivity of DYZ and 4YSZ exhibits a decreasing trend with the increase in temperature from 295 K to 1873 K, as depicted in The thermal conductivity of 4YSZ predicted from the simulation is higher than that measured in the experiment (2.3–3.0 W/m·K)111534155Z, and In addition, finite-size effects could result in the discrepancy of the thermal conductivity of DYZ and 4YSZ between the experiment and MD simulation. The thermal conductivity could be influenced by the length of the simulation cell L3+ and Y3+ cations on the calculated thermal conductivity of ZrO2 via MD simulation is in good agreement with the experimental measurement. At 1300 °C, there is no reaction between DYZ and Al2O3, whereas a minor amount of Al5Y3O12 and Dy3Al5O12 formed due to calcination at 1350 °C. It is discovered that DYZ exhibits lower thermal conductivity and has the potential to be used up to 1300 °C as a new ceramic TBC material.In summary, fluorite DYZ powders and tetragonal 4YSZ powders have been synthesized via a sol-gel route. The particles exhibit polyhedral morphology with sharp edges and pores. The thermal conductivity of DYZ is lower than that of 4YSZ and the phonon-defect scattering of DYZ is stronger than that of 4YSZ. Theoretical thermal conductivity of DYZ is lower than that of 4YSZ, and the density of DYZ is higher than that of 4YSZ from 295 K to 1873 K. The influence of doping DyHow to cite this article: Qu, L. et al. An Atomistic-Scale Study for Thermal Conductivity and Thermochemical Compatibility in (DyY)Zr2O7 Combining an Experimental Approach with Theoretical Calculation. Sci. Rep.6, 21232; doi: 10.1038/srep21232 (2016).


The length of the designed PBS can be reduced further to 620 nm while still offering PERs of 15 dB, realizing a densely photonic integrated circuit. Considering the fabrication tolerance, the designed PBS allows for large geometrical deviations of ±20 nm while restricting PER variations to within 1 dB, except for those in the nanoscale gaps smaller than 10nm. Additionally, we also address the input and ouput coupling efficiencies of the proposed PBS.We propose an ultracompact broadband polarization beam splitter (PBS) based on a combined hybrid plasmonic waveguide (HPW). The proposed PBS separates transverse-electric (TE) and transverse-magnetic (TM) modes using a bent lower HPW with vertical nanoscale gaps and a straight upper HPW with a horizontal nanoscale gap, respectively, without relying on an additional coupling region. This design considerably reduces the length of the PBS to the submicron scale  while offering polarization extinction ratios (PERs) of ~19 dB (~18 dB) and insertion losses (ILs) of ~0.6 dB (~0.3 dB) for the TE (TM) mode over an extremely broad band of 400 nm (from  To fulfill ever-increasing transmission demands of optical communication systems, polarization division multiplexing (PDM) plays a pivotal role in manipulating optical signals for chip-scale photonic integrated circuits (PICs)1234567891011121314151617181920212223242526272829303132333468910111213141516171819212223242627293031326789101112131415161718192021222324283233To achieve satisfactory PERs, AME-based PBSs689101112131415161718192122232435262729303233Among the aforementioned PBSs67891011121314151617181920212223242526272829303132333435891011121314151617181989111517394041et al.1613Considering the trade-off between mode confinement and propagation loss, an HPW structure434445461112131416182) and Ag and a straight upper HPW formed by a nanoscale layer of SiO2 sandwiched between Si and Ag layers. In this way, TE and TM modes are supported by the bent lower and straight upper HPWs, respectively, without the requirement of a coupling region that is typically indispensable in DC-based PBSs. The key idea allows the length of the proposed PBS to be shortened to the submicron scale while retaining satisfactory PERs and broad operating bandwidths. Furthermore, the fabrication tolerance is also discussed in detail to assess the feasibility of the designed PBS.In this paper, we propose an innovative design for a PBS based on a combined HPW (CHPW) consisting of two parts: a bent lower HPW deposited on a SOI platform and formed by a high-index silicon (Si) core sandwiched between two low-index nanoscale layers of silicon dioxide (SiO2 substrate (depicted in blue). To clearly view the interior structure, 2, and Ag (depicted in gray) layers. The bent lower HPW structure is formed by a Si core that is sandwiched successively between SiO2 and Ag layers, and the straight upper HPW structure  and TM  modes are guided through the lower and upper parts, respectively, and the energies of the two modes are concentrated primarily in the SiO2 nanoscale layers. The cross-sectional views of the proposed PBS at the input port, at the output port for transmitting the TM mode (port 2), and at the output port for transmitting the TE mode (port 1) are shown in The schematic of the proposed PBS  consiststructure  that is 2 substrate (blue) is prepared for depositing with a negative photoresist (PR) thin film (yellow) to define the inner Si region by the preceding mask of the bent TE channel, a PR exposure with ultraviolet (UV) light, development, and an etching process. (2) A well with width w1 and height h1 is formed by etching SiO2 and lifting off the PR film. (3) A Si layer with height of h1 is deposited using chemical vapor deposition (CVD) in the well. After that, we proceed chemical mechanical polishing (CMP) process to obtain a flat plane. (4) The SiO2 walls at both sides of Si with width of 2w2 + w1 are defined by the processes including a PR film deposition, a patterned mask, a PR exposure, development, and an etching process. (5) With the help of a patterned mask, two SiO2 vertical walls are formed by reactive ion etching (RIE) and then the PR is lifted off. (6) The Ag regions with width of w3 − 2w2 − w1 are first defined by using the patterned mask of bent TE channel and depositing PR film. Next, the TM channel is defined by lifting off the PR film of that part using the patterned mask of TM channel. (7) An Ag layer with height of h1 + h2 is deposited. (8) Lifting off the PR film forms the final bent TE channel and the straight TM channel without SiO2 and Si layers yet. (9) A SiO2 layer with height of h1 + h2 + h3 is deposited using thermal oxidation. Next, using CMP to obtain a flat SiO2 surface. (10) After depositing PR film, we use the patterned mask of TM channel, a PR exposure, development, and an etching process to form PR film with width of w3. (11) With the help of a patterned mask, etching SiO2 by RIE forms the SiO2 layer with width of w3 and height of h3 on the top of Ag layer of the straight TM channel. (12) After removing the PR film, a Si layer is deposited with height of h1 + h2 + h3 + h4. Next, using CMP to obtain a flat Si surface. (13) After depositing PR film on the Si layer, using the patterned mask of TM channel, a PR exposure, and development to form PR film with width of w3. (14) Finally, the proposed device is formed by etching Si and removing the PR film.The fabrication processes of the proposed device are schematically shown in 2, and Ag used in this model are εSi = 11.937εSiO2 = 2.088εAg = −129.2 + 3.285iλ = 1,550 nm. Considering the trade-offw1 = 80 nm, w2 = 5 nm, w3 = 240 nm, h1 = 200 nm, h2 = 50 nm, h3 = 5 nm, and h4 = 200 nm (see Ex) and TM (Ey) modes . The results calculated for the present structure are Ae/Ao = 3.1 × 10−3 (1.24 × 10−2) and Lm = 10.91 (20.18) μm for the TE (TM) mode. For the TE mode, the mode size is smaller than that of the TM mode because of the complete coverage by metal; however, one disadvantage is the higher ohmic losses of the metals. Ez, of TE and TM modes, respectively, which are responsible for metal attenuationEz fields shown in Ex or Ey fields shown in Ez fields of TE and TM modes are concentrated in the metal and in the upper Si, respectively. Therefore, the ohmic loss of the TE mode (Lm = 10.91 μm) is larger than that of the TM mode (Lm = 20.18 μm), demonstrating the calculated propagation lengths. The numerical results above show that the proposed HPW structure is capable of accomplishing nanoscale field localization while offering sufficiently long propagation distances (tens of micrometers) and can thus be applied to construct an ultra-small PBS.To design an optimal PBS, we first analysed the mode properties of the proposed PBS. The relative permittivities of Si, SiO0 nm see . The effR = 800 nm. We observe that the two modes are separated independently into the upper and lower parts of the proposed PBS. Unlike in typical DC-based PBSs8910111213141516171819R are shown in TM (~18 dB) and ILTM (~0.2 dB) vary moderately as R increases because the TM mode propagates in the straight upper waveguide rather than in the bent lower one. In contrast, PERTE and ILTE increase significantly as R increases, as shown in TE as R increases results from the decreased bending radiation transferring to port 2. For the ILTE, the increase in propagation distance due to the increase in R leads to greater ohmic loss, as shown in R is also shown in TE  is the sum of the propagation and bending losses. We see that the variation of the bending loss is between 0.03 to 0.05dB without exhibiting monotonous decrease as the R increases because of the presence of another waveguide transmitting TM mode. As shown in TE is resulted from the propagation loss because the most power is highly confined in the vertical SiO2 layers surrounding by Ag. In particular, PERTE and PERTM exceed 15 dB and 18 dB, respectively, even though R is reduced to 500 nm. Under the condition R = 500 nm, the dimensions of the designed PBS are only 620 nm (length) × 620 nm (width) × 455 nm (height). Under the condition R = 800 nm, PERTE further increases to above 18 dB. For the IL, which is responsible for the intrinsic losses of plasmonic waveguides, the increase of ILTE as R increases is greater than that of ILTM, because the propagation loss of the TE mode (Lm = 10.91 μm) is approximately twice that of the TM mode (Lm = 20.18 μm). However, ILTE (~0.6 dB at R = 800 nm) is still low. Overall, to achieve satisfactory performance (PER > 18 dB and IL < 0.6 dB at R = 800 nm), the dimensions of the proposed PBS must be about 920 nm × 920 nm × 455 nm , and thus, the proposed design has great potential to realize high-density PICs with good performance. Another pivotal characteristic for assessing a PBS is its operating bandwidth with satisfactory PER and IL. Considering the used material dispersions48w1, w3, h1, h2, and h4 were all within 1 dB and 0.2 dB, respectively, even when these parameters were varied by up to ±20 nm. This stability results from the majority of the energies of the hybrid SPP modes being concentrated in the thin SiO2 layers . Consequently, we first studied the PERs and ILs while varying h3 (Δh3), and the results are shown in h3 range from −2 nm to 5 nm, because the originally designed thickness h3 was only 5 nm. For the TM mode, the values of PERTM and ILTM were moderately influenced by Δh3. It can be understood that a large portion of the energy resides in the upper Si region, in addition to that concentrated in the thin SiO2 gap. In contrast, as expected, PERTE and ILTE are approximately constant as h3 varies. The other critical geometrical parameter is the width (w2) of the vertical SiO2 regions supporting the TE mode. The calculated PERs and ILs are shown in TM and ILTM are slightly influenced by Δw2, as expected. In contrast to PERTM, PERTE is significantly influenced by Δw2, as shown in w2 causing looser energy confinement in the TE mode. Therefore, more energy is coupled to port 2 because of larger bending radiation. This causes PERTE to be reduced significantly. In contrast, shrinking the width of SiO2 increases PERTE due to better energy confinement. From the above discussions of the fabrication tolerances, the width w2 results in the most significant influence on PERTE. As a result, we conclude that the ability to precisely control the critical parameter w2 determines the PERTE performance of the proposed PBS. Fortunately, the other geometrical parameters besides w2 have more moderate influences on the PERs and ILs. The results confirm the high fabrication tolerances of the proposed PBS, except for with respect to Δw2. For further improving the PERs of TE and TM simultaneously to better values larger than 20 dB, we can decrease the thicknesses of SiO2 layers between Si and Ag. For instance, the PERs of the TE mode are 21.0 dB and 22.1 dB at the conditions of w2 = 4 nm and 3 nm, respectively, as shown in h3 = 2 nm, which is not involved in TE is concerned, increasing the radius of curvature of the bent waveguide to 1100 nm can reach 20.85 dB.The propagating field distributions of TE and TM modes are shown in λ = 1.55 μm. The output port for transmitting TE mode is connected with the same Si stripe waveguide as the input one. Nevertheless, the output port for transmitting TM mode is connected with a slotEx) for the condition of R = 800nm as shown in Ez) of the TE mode is also shown in z-direction (input coupling) to the minus x-direction (output coupling). Likewise, the field distributions 100 nm before (CC′) and after (DD′) the output coupling interface are shown in the insets of x-direction at the planes CC′ and DD′, and the calculated value is ~94.7%. Note that the input and output coupling efficiencies are almost identical due to the same structure connected. For completely analyzing the performances of the proposed PBS, we calculate the total coupling efficiency of the TE mode defined by the ratio of power between the planes AA′  and DD′ . The calculated value of the total coupling efficiency is ~58.5%. In TE at R = 800nm is 0.533dB (power transmitted ratio within the bent waveguide is ~88.3%) and the bending loss is fairly low relative to the propagating loss of a highly confined plasmonic waveguide mode. Comparing with the total coupling efficiency of ~58.5%, we calculate the total power transmitting ratio (~79.1%) by summing up the input (~94.5%), output (~94.7%), bending, and propagating (~88.3%) losses. We found that the obvious difference of ~20.6% between the two calculations is resulted from the stronger bending loss of while coupling with the TE mode of the Si stripe waveguide (not highly confined mode) than that of the guided plasmonic TE mode (highly confined mode). Now, we turn attention to the TM mode analysis. The propagating field distribution (Ey) of the TM mode and the field distributions at the planes of EE′, FF′, GG′, and HH′ are shown in Considering the practical applications of the proposed PBS, we address the input and output coupling efficiencies in detail. The light is coupled into the input port by a Si stripe waveguide with a width of 300 nm and a height of 300 nm supporting both the fundamental TE and TM modes at 2) with nanoscale gaps and Ag, and the straight upper HPW was formed by a nanoscale gap of SiO2 sandwiched between Si and Ag layers. The innovative concept of the proposed PBS was to separate TE and TM modes with bent lower and straight upper HPWs, respectively, without coupling one of the guiding modes to the adjacent channel. As a result, the length of the designed PBS became extremely short. With dimensions of 920 nm (length) × 920 nm (width) × 455 nm (height), which make it the smallest PBS to date, the PER of the TE (TM) mode was ~19 dB (18 dB), and the IL was ~0.6 dB (0.3 dB) over an extremely broad band of 400 nm (from λ = 1300 nm to 1700 nm). In particular, the wavelength insensitivity of the proposed PBS properties resulted from avoiding the phase-matching requirement of DC-based PBSs. The input and output coupling efficiencies of the TE and TM modes are also addressed. For the TE mode, both the input and output ports are connected with Si stripe waveguides, and the two coupling efficiencies are about 94.5%. For the TM mode, the input coupling efficiency connected with a Si stripe waveguide is about 88.5% and the output efficiency connected with a slot waveguide is about 95.2%. Adding in the propagating ohmic loss and bending loss of the proposed PBS, the total coupling efficiencies of the TE and TM modes are about 58.5% and 77.3%, respectively. When the dimensions were further reduced to 620 nm × 620 nm × 455 nm, the proposed PBS still retained high PERs of >15 dB. These results indicate that the proposed PBS has the potential to realize high-density PICs with satisfactory performances.We have reported a novel PBS based on a combined HPW. The proposed PBS consisted of two HPW structures arranged vertically. The bent lower HPW deposited on an SOI platform was formed by a silicon core sandwiched successively between silicon dioxide . The normalized mode area (Ae/Ao) and propagation length (Lm = λ/[4πIm(ne)]) of a guided mode are essential features to characterize the figure of merit (FOM) of a plasmonic waveguideAo = λ2/4 denotes the diffraction-limited area of light in a vacuum and λ is the operating wavelength. The effective mode area, Ae, in Eq. Wm, and the peak value of the energy density, W(r), which is defined in Eq. 44First, the modal properties at the input port are obtained by solving the Helmholtz equation using the boundary mode analysis of the simulation software COMSOLandω is the angular frequency, ε(r) is the relative permittivity, μ0 is the vacuum permeability, and |E(r)|2 and |H(r)|2 are the intensities of the electric and magnetic fields, respectively. The propagation length represents the distance over which the mode energy intensity is attenuated to 1/e of the input light, where Im(ne) is the imaginary part of the effective mode index. The calculated window (500 × 5000 μm2) with the scattering boundary condition mimicking the necessary open boundary for solving mode characteristics is enough large to ensure no interference from boundary to affect the results. In addition, convergence is also tested by fining the meshes for certain thin regions and sharply variant fields.where After obtaining the mode characteristics of the designed PBS, we studied its performance by launching the TE and TM SPP modes into the input port. For evaluating the transmission characteristics of a PBS, we need to investigate the PERs and ILs of a specific mode. Here, the TE and TM modes are defined in Eqs 111219andPi is the mode power at port i .where How to cite this article: Chang, K.-W. and Huang, C.-C. Ultrashort broadband polarization beam splitter based on a combined hybrid plasmonic waveguide. Sci. Rep. 6, 19609; doi: 10.1038/srep19609 (2016).


The migration velocity of this interface was confirmed to be much faster than that of peritectic transformation, so this migration was mostly caused by superheating of primary Ni3Sn2 phase below TP, leading to nucleation and migration of liquid film at this interface. This migration can be classified as a kind of liquid film migration (LFM), and the migration velocity at the horizontal direction has been confirmed to be much faster than that along the direction of temperature gradient. Analytical prediction has shown that the migration of liquid film could be divided into two stages depending on whether primary phase exists below TP. If the isothermal annealing time is not long enough, both the liquid film and the primary/peritectic interface migrate towards the primary phase until the superheated primary phase has all been dissolved. Then, this migration process towards higher temperature is controlled by temperature gradient zone melting (TGZM).The migration of the primary/peritectic interface in local isothermal condition is observed in dendritic structure of Sn–Ni peritectic alloy after experiencing interrupted directional solidification. It was observed that this migration of primary Ni Three different phases are involved during peritectic solidificaitonNucleation of liquid films in the interior of the solid grains has also been found in directional melting experiments which have been carried out in some alloys141518182021222324252627283Sn2 phase and peritectic Ni3Sn4 phase are intermetallic compounds with narrow solubility ranges has been selected. In this kind of peritectic system, the driving force for peritectic transformation In peritectic systems, the nucleation and migration of the liquid films can lead to the change in both the position and morphology of the primary/peritectic interface where the liquid films located. In addition to the solid/liquid interface, the primary/peritectic interface is formed after peritectic reaction like grain boundaries in single phase alloys. Although it has been theoretically predicted that the nucleation and migration of liquid films could take place at primary/peritectic interfaceL = 1040 °C with a primary precipitation of Ni3Sn2 phase: L → Ni3Sn2; followed by a peritectic reaction at TP = 798 °C: L + Ni3Sn2 → Ni3Sn4; then at TE = 231.15 °C, the remaining liquid was quenched as the eutectic (Ni3Sn4 + Sn). In this work, Ni3Sn2/Ni3Sn4 phases are the primary α/β phases in the Sn-Ni peritectic system. In the following analysis and discussions, “Ni3Sn2” and “Ni3Sn4” are used when illustrating the experimental observations in this work while “α” and “β” are used when discussing a general solidification case. The Typical BSE (backscattered electron) microstructures of the longitudinal sections of directionally solidified Sn–36at%Ni alloy after different isothermal annealing time are shown in 3Sn2/peritectic Ni3Sn4 phases, respectively; and the remaining white is the eutectic483Sn2 + liquid) mushy zone, the (Ni3Sn2 + Ni3Sn4 + liquid) mushy zone, below TE is the complete solid region. During isothermal annealing, the (Ni3Sn2 + Ni3Sn4 + liquid) mushy zone gradually changes into the (Ni3Sn4 + liquid) one.It can be observed from 3Sn2/peritectic Ni3Sn4 phase gradually decreases/increases with increasing isothermal annealing time t. Simultaneous migration of the primary/peritectic interface towards the primary Ni3Sn2 phase can be observed. Besides, distinct from the structure feature of peritectic transformation3Sn4 phase is larger at higher temperature below TP . This means that the Ni3Sn2/Ni3Sn4 interface migrates more quickly at higher temperatures towards primary Ni3Sn2 phase. In addition, a number of liquid films which are elongated along temperature gradient can be observed in solid phases after isothermal annealing. Most of these elongated liquid films are located at the Ni3Sn2/Ni3Sn4 interface. Finally, after isothermal annealing, the relatively flat Ni3Sn2/Ni3Sn4 interface becomes much more curved, and the distances from this curved Ni3Sn2/Ni3Sn4 interface to the center of primary dendrite stem are different at different local temperatures.More importantly, the position and morphology of the primary/peritectic interface changes in several aspects during isothermal annealing. The most obvious one is that, the volume fraction of primary Ni3Sn2 + Ni3Sn4 + liquid) mushy zone becomes the (Ni3Sn4 + liquid) mushy zone. In this case, the Ni3Sn2/Ni3Sn4 interface disappears in the (Ni3Sn4 + liquid) mushy zone. Contrary to the regular arrangement of solid phases in the (Ni3Sn4 + liquid) mushy zone, the arrangement of Ni3Sn2 phase in the (Ni3Sn2 + liquid) mushy zone is quite irregular and complex. The Ni3Sn2 grains with irregular morphology exist at the bottom of the (Ni3Sn2 + liquid) mushy zone, and numerous liquid droplets of different sizes and morphologies are located inside these grains. In addition, this irregularity of both Ni3Sn2 grains and the liquid droplets within them extends from the bottom to the top of (Ni3Sn2 + liquid) mushy zone with increasing isothermal annealing time.It is interesting to note that the distribution of liquid films is dependent on the isothermal annealing time t. When the isothermal annealing time t is above 15 min, the  of peritectic Nix is the thickness of peritectic phase formed through peritectic transformation. The explanations of these concentrations are as follows: Cβ is average concentration of the peritectic β phase. Dβ is the average diffusion coefficient of peritectic β phase, and can be expressed as:where ∆D0 is a physical constant depending on alloy composition, Ra is gas constant, 8.314 J/mol·K. Q is the activation enthalpy, respectively. In the Sn–Ni peritectic system, the physical constant D0  = 5 × 10−9m2/s, the activation enthalpy Q = 19150J/mol is obtained by averaging the values from previous researches323Sn4 phase during isothermal annealing. L increases more quickly at higher temperatures, which means that the Ni3Sn2/Ni3Sn4 interface migrates more quickly towards the Ni3Sn2 phase at higher temperatures. Comparison between 3Sn2/Ni3Sn4 interface. Besides, it can be found from 3Sn4 phase by peritectic transformation is more obvious at lower temperatures. This is different from the dependence of L on temperature  mushy zone can be attributed to irregular morphology of Ni3Sn2 grains in this mushy zone. Compared with the arrangement of Ni3Sn4 grains below TP , the arrangement of Ni3Sn2 grains above TP is far from uniform. Since the liquid films located within these irregular Ni3Sn2 grains can be easily in contact with the liquid phase outside of these grains, disappearance of them occurs quite easily. Irregular morphology of Ni3Sn2 grains can be caused by the following two reasons. On the one hand, although the primary dendrite arms are more or less parallel to temperature gradient, remelting/resolidification of secondary and higher order branches during isothermal annealing leads to irregular morphology of the Ni3Sn2 grains. On the other hand, the volume fraction of liquid is higher at the lower part of (Ni3Sn2 + liquid) mushy zone due to nucleation of liquid phase at the Ni3Sn2/Ni3Sn4 interface at TP . Therefore, thermosolutal convection due to the density difference between Ni and Sn atoms is produced. The morphology of Ni3Sn2 grains should be more complex in existence of thermosolutal convection. Furthermore, it is interesting to note that the migration of liquid phase influences the non-uniform morphology of Ni3Sn2 grains which can also lead to the disappearance of liquid droplets themselves.Disappearance of these liquid films in the (Ni3Sn2/L) and β/L(Ni3Sn4/L) interfaces have been presented in 3Sn2/Ni3Sn4 interface are faster at higher temperatures, which is consistent with the experimental observation. In this case, the migration distances Lα and Lβ are all larger at higher temperatures. It is interesting to note that since the resolidification velocity at the tail of liquid film (β/L interface) is larger than the remelting velocity at the front of liquid film (α/L interface), so the thickness of the liquid film in the direction perpendicular to temperature gradient l should decrease as migration proceeds. Once the difference, Lβ−Lα is shorter than the thickness of the liquid film in the direction perpendicular to temperature gradient l, this liquid film is disappeared. Although liquid films gradually disappear during the migration process, nucleation of liquid films at the Ni3Sn2/Ni3Sn4 interface continues as superheated solid phases still exist. As a result, migration of liquid films and the Ni3Sn2/Ni3Sn4 interface where these films located proceeds till the final dissolution of α phase.Predictions of the migration distances of both the α/L, while the driving force for this process is the concentration gradient across the liquid film.Migration of liquid phase can be divided into two stages depending on the isothermal annealing time. If this time is not long enough, migration of the liquid film continues until the superheated primary phase has all been dissolved. Then, migration of the liquid film is controlled by temperature gradient zone melting (TGZM).The migration of primary/peritectic interface has been analyzed in a Sn–Ni peritectic alloy through interrupted directional solidification. And the following conclusions can be made.Sn-36at.%Ni peritectic alloy was induction melted under an argon atmosphere from pure Ni and Sn (99.9%). As-cast rods of 3 mm in diameter and 110 mm in length were cut from the ingot. The experiments consisting of melting followed by directional solidification were carried out in a Bridgman-type system consisting of a resistance furnace, a water cooled liquid metal bath filled with liquid Ga–In–Sn alloy, which has been described in previous work3-20 ml HCl-180 ml H2O for further analysis. The microstructure of the longitudinal section of rods was analyzed by scanning electron microscopy (SEM (Quanta-200)). Energy dispersive X-ray spectrometer (EDS) was applied to determine the composition of phases.Interrupted directional solidification of Sn-36at.%Ni peritectic alloy can be divided into three successive steps. First, the furnace was heated to 1250 °C to melt the as-cast samples alloy during 2 h, and then was held for 30 min to homogenize the melt. Then, the samples were directional solidified at a growth velocity of 5 μm/s in a constant temperature gradient (20 K/mm). When a predetermined growth distance of 30 mm reached, the samples were kept stationary for different isothermal annealing time . Then, the samples were quenched into liquid Ga-In-Sn alloy quickly to preserve the microstructure. And the samples were longitudinally sectioned, polished and etched with a solution of 10 g FeClHow to cite this article: Peng, P. et al. On migration of primary/peritectic interface during interrupted directional solidification of Sn-Ni peritectic alloy. Sci. Rep. 6, 24512; doi: 10.1038/srep24512 (2016).


First proliferating ‘slender' bloodstream forms differentiate to non-dividing ‘stumpy' forms arrested in G1. Second, in response to environmental cues, stumpy bloodstream forms re-enter the cell cycle and start to proliferate as procyclic forms after a lag during which both cell morphology and gene expression are modified. Nearly all arrested cells have lower rates of protein synthesis when compared to the proliferating equivalent. In eukaryotes, one mechanism used to regulate the overall rate of protein synthesis involves phosphorylation of the alpha subunit of initiation factor eIF2 (eIF2α). The effect of eIF2α phosphorylation is to prevent the action of eIF2B, the guanine nucleotide exchange factor that activates eIF2 for the next rounds of initiation. To investigate the role of the phosphorylation of eIF2α in the life cycle of T. brucei, a cell line was made with a single eIF2α gene that contained the phosphorylation site, threonine 169, mutated to alanine. These cells were capable of differentiating from proliferating bloodstream form cells into arrested stumpy forms in mice and into procyclic forms in vitro and in tsetse flies. These results indicate that translation attenuation mediated by the phosphorylation of eIF2α on threonine 169 is not necessary for the cell cycle arrest associated with these differentiation processes.The trypanosome life cycle consists of a series of developmental forms each adapted to an environment in the relevant insect and/or mammalian host. The differentiation process from the mammalian bloodstream form to the insect-midgut procyclic form in  The process includes two differentiation steps in vivo, first proliferating ‘slender' bloodstream forms differentiate to non-dividing ‘stumpy' forms arrested in G1 Kinetoplastids are protozoa and a large number of species have evolved to infect humans and/or animals. Many of the pathogenic species have complex life cycles and have evolved to proliferate in different niches within one or more host through evolution of a series of developmental forms each adapted to an environment in the relevant invertebrate and, sometimes, vertebrate host. The differences between one developmental form and another include alterations in gene expression and cellular morphology. The transition from one developmental form to another has been used to investigate the regulation of these processes Selective transcriptional control by RNAPII is unlikely to play a role in the G1 arrest that occurs on differentiation to stumpy forms. In trypanosomes, genes occur in long tandem arrays, usually encoding functionally unrelated proteins, and are transcribed polycistronically from occasional transcription start sites; co-transcriptional processing results in individual monocistronic mRNAs. This lack of transcriptional regulation of individual genes means that the relative levels of individual mRNAs are determined post-transcriptionally. RNAPII transcription must continue in arrested stumpy cells as some mRNAs have increased levels In eukaryotes, one mechanism used to regulate the overall rate of protein synthesis involves the phosphorylation of serine 51 (S51) in the eIF2α. eIF2 is a trimeric G-protein that forms a ternary complex with the initiator methionyl tRNA that delivers the Met-tRNA to the pre-initiation complex. At the start codon, release of eIF2 occurs after GTP hydrolysis. The effect of eIF2α phosphorylation is to prevent the action of eIF2B, the guanine nucleotide exchange factor that activates eIF2 for the next rounds of initiation. This is turn reduces the amount of available ternary complex and the rate of translation initiation. The kinases that phophorylate eIF2α contain a catalytic domain attached to different regulatory domains. The best conserved are GCN2, which is activated by amino acid deficiency, and PERK which is activated by an increase in unfolded proteins in the ER. In yeast and mammals, eIF2α phosphorylation also initiates changes in gene expression promoted by proteins whose synthesis is paradoxically increased when there is increased eIF2α-P in cells, such as yeast GCN4 and ATF4 in mammals. Both are transcription factors that regulate the expression of hundreds of genes necessary for the cells to recover from the initial stress Trypanosoma sp. and threonine166 in Leishmania sp T. brucei eIF2α T169 is phosphorylated in vitro by eIF2K2, one of the three eIF2α kinases in trypanosome genomes In vivo, this same residue is phosphorylated by eIF2K2 activated by different stress conditions in T. cruzi and Leishmania. In Leishmania, phosphorylation of eIF2α T166 has been shown to be necessary for the normal kinetics of differentiation of promastigotes into amastigotes but not for the process itself T. cruzi, phosphorylation of eIF2α is also required for nutrient-induced differentiation from non-infective epimastigotes into infective metacyclic trypomastigotes, and again the phosphorylation of eIF2α T169 correlates with the levels of overall translation Trypanosomes separated early from other eukaryotes and have some divergent features in the structure and regulation of eIF2. First, eIF2α has an amino terminal extension of >100 residues when compared with animals, fungi or higher plants. Second, the phosphorylated residue that aligns with S51 is threonine 169 (T169) in T. brucei it has been shown that phosphorylation of eIF2α T169 is not necessary for either arrest or the formation of stress granules during heat shock T. brucei cell line containing a single eIF2α gene with a T169A mutation was used to determine whether phosphorylation of eIF2α T169 is necessary for either the growth arrest that occurs in stumpy bloodstream forms or the subsequent differentiation to procyclic forms. Both differentiation processes occurred with the same kinetics as the wild type control.In 22.1T. brucei EATRO 1125 bloodstream form cells were grown in HMI-9 medium salts 2.27 cells were harvested and washed twice in serum free HMI-9. The cells were resuspended in 100 μl SDS-PAGE sample buffer and incubated at 100 °C for 3 min. Standard SDS-PAGE and Western blotting procedures were used, rabbit anti-eIF2α was diluted 1:5000 1 × 102.3The plasmid for deletion of the first allele of eIF2α and both plasmids for the substitution of the second allele for either the mutant or the wild type TbeIF2α have been previously described 2.47 cells resuspended in 100 μl of Amaxa Human T-cell buffer with 10 μg of linearized plasmid DNA in 0.2 mm cuvettes and program X-001 of the Amaxa Nucleofactor II (Lonza). Transfectants were selected and cloned in HMI-9 medium supplemented with G418 (2.5 μg/ml) and/or blasticidin (5 μg/ml) as required.Transfections were performed using 3 × 102.5After the antibiotic selection, clones were screened by amplification and sequencing of the region corresponding to the phosphorylation site region (T169). PCR was performed with Expand High Fidelity PCR (Roche) using oligonucleotides D526 (ATGGCAGCTTACGGTATAGTG) and D527 (AACCTCATTTCCCTTGAAGAA); the amplified region covered nucleotides 1–675 of the open reading frame. The PCR products were sequenced without cloning using oligonucleotide D527 as a primer.2.65 cultured bloodstream form trypanosomes. Four mice were used for each of the eIF2A T169A/- and eIF2A T169T/-cell lines. The subsequent parasitaemia was followed daily from day 2, trypanosome density measured using a haemocytometer after diluting 5 μl blood in 45 μl 0.83% ammonium chloride solution and further 10-fold dilutions as necessary.CD1 mice were inoculated intraperitonially with between 5 and 15 × 102.7In vitro differentiation was initiated from blood collected 5 days after infection, as above. All populations were predominantly stumpy in morphology. The blood containing the parasites was incubated in DTM medium with 3 mM citrate/cis-aconitate at 28 °C at a density of 2 × 106 trypanosomes/ml. After 6 h the red blood cells had settled and half the supernatant was removed to a new culture flask and proliferation rate was measured after 24 h.2.8Glossina pallidipes) were fed with bloodstream form or cultured procyclics in washed red blood cells from horse (estimated 8 × 106 parasites/ml), supplemented with 10 mM l-glutathione to increase infection rates 24 to 48 h post-eclosion and as the first feed, experimental tsetse flies  that contained a T169A mutation as previously described eIF2A+/− cell lines. Second, a T169A mutation was introduced into the remaining allele, eIF2A T169A/-. This step altered the 3′ untranslated region of the eIF2A gene and a control cell line was made with the same change in the 3′ untranslated region but with wild type eIF2A open reading frame sequence, eIF2A T169T/-.eIF2A open reading frame from genomic DNA followed by direct sequencing of the PCR product , eIF2A T169T/- and eIF2A T169A/-, were used to infect tsetse flies to investigate these transitions in two different experiments (eIF2A T169T/- and eIF2A T169A/- showed reduced ability to establish salivary gland infection. Taken together, these observations indicate that phosphorylation of eIF2α at T169 is not necessary for the differentiation as far as the proventriculus, including the cell cycle arrest prior to the asymmetric cell division.There are at least three further points in the life cycle that include a cell cycle arrest in G1. One occurs in procyclic cells as they migrate towards and invade the tsetse proventriculus eriments . In the eriments . No infeeriments . However4eIF2A allele expressing a non-phosphorylatable eIF2α T169A was able to enter and exit quiescence in a similar manner to a wild type control. The ability of the mutant cells to enter and leave cell cycle arrest with wild type kinetics provides strong evidence that the phosphorylation of T169 is not sufficient to promote these transitions that are associated with changes in protein synthesis. The only phenotype observed was a slightly slower proliferation rate as bloodstream forms in culture.When a cell switches between quiescence and proliferation both the identity of proteins made and the rate of protein synthesis are altered. In trypanosomes, the non-selective polycistronic transcription of protein coding gene arrays means that there is an apparent conflict between maintaining/increasing the expression of proteins associated with quiescence and decreasing the overall rate of protein synthesis. Here, any role for phosphorylation of eIF2α on T169 in regulating differentiation between proliferative and quiescent developmental forms has been investigated. The main finding is that a cell line with a single T. cruzi and Leishmania infantum. In T. cruzi epimastigotes, the level of phosphorylation of T169 increases under a nutritional stress that results in differentiation to metacyclics, at the same time as the number of polysomes decreases, providing evidence that the overall rate of protein synthesis could be regulated by eIF2α phosphorylation. Overexpression of eIF2α mutated in the phosphorylation site has a dominant effect and reduced differentiation from the proliferative epimastigote to the non-proliferative metacyclic form Leishmania, a slowing in growth associated with differentiation of promastigotes to amastigote forms also coincides with eIF2α phosphorylation and overexpression of an eIF2α kinase deleted for its regulatory domain and sequences necessary for correct localization slowed differentiation T. cruzi and are consistent with a role for eIF2α phosphorylation in the differentiation of Leishmania after the uptake by macrophages and acidification in the parasitophorous vacuole.In kinetoplastids, the evidence for a functional role for eIF2α T169 phosphorylation in regulating the overall rate of protein synthesis comes from T. brucei slender to non-proliferating stumpy forms does not occur as a consequence of nutritional starvation or environmental changes. Similarly, the formation of procyclics in the insect gut does not appear to depend on the lack of nutrients T. brucei and the other studied kinetoplastids, and they represent the first direct evidence indicating that phosphorylation of eIF2α T169 is not necessary for controlling these T. brucei differentiation events In contrast, the differentiation of proliferating T. brucei transformation of epimastigotes to metacyclics in the insect salivary gland, a differentiation process that occurs in an environment that is poor in nutrients.Given the relevance of phosphorylation of eIF2α at T169, or equivalent residue, in differentiation events in other parasites, it is possible that this phosphorylation and consequent inhibition of translation could be required for the


Despite its fleeting existence, H2CO3 plays an important role in the global carbon cycle and in biological carbonate-containing systems. The short lifetime in water and presumed low concentration under all terrestrial conditions has stifled study of this fundamental species. Here, we have examined CO2/H2O mixtures under conditions of high pressure and high temperature to explore the potential for reaction to H2CO3 inside celestial bodies. We present a novel method to prepare solid H2CO3 by heating CO2/H2O mixtures at high pressure with a CO2 laser. Furthermore, we found that, contrary to present understanding, neutral H2CO3 is a significant component in aqueous CO2 solutions above 2.4 GPa and 110 °C as identified by IR-absorption and Raman spectroscopy. This is highly significant for speciation of deep C–O–H fluids with potential consequences for fluid-carbonate-bearing rock interactions. As conditions inside subduction zones on Earth appear to be most favorable for production of aqueous H2CO3, a role in subduction related phenomena is inferred.Carbonic acid (H Yet, the exact crystal structure of β-H2CO3 is still unknown. The FT-IR and Raman spectra of solid H2CO3 below 220 K at low pressure are now well established and several theoretical studies have reported on the structure and stability of H2CO3 with respect to decomposition to CO2 and H2O as well as on the relative stability of its isomers and on their vibrational characteristics78131412CO3 at elevated pressure has been predicted by ab initio molecular dynamic simulations2CO3 (aq) have been found up to 1.94 GPaCarbon dioxide CO, when diacid H2CO, but theon2 ref. ; and dir2O/CO2 mixtures experimentally at high pressure and temperatures in a diamond anvil cell (DAC), looking for evidence of increased stability of molecular H2CO3 in aqueous solution at elevated pressure. Within the Earth, at depths corresponding to pressures of up to 4.6 GPa , temperatures are heterogeneously distributed2O/CO2 mixtures were compressed to the desired pressure and then heated by irradiation with a CO2 laser. The laser was focused to irradiate only a fraction of the sample. In this way, the behavior of the system at high T can be investigated in the center of the heated area while phenomena of the transition down to room temperature can be investigated on the hot spot periphery. A solid product was synthesized during laser heating and the pressure-dependence of the vibrational modes of this product was investigated up to 9.1 GPa at ambient temperature. Additionally, the stability of the solid product with respect to pressure was investigated by compression to 25 GPa after synthesis at 4.3 GPa. In the second set of experiments, the sample was heated resistively to up to 280 °C after compression to the desired pressure. During resistive heating, the evolution of the system was monitored in situ by IR absorption spectroscopy. In both sets of heating experiments, the pressure range from 1.5 to 4.6 GPa was covered.In this work, we studied H2/H2O mixtures with a wide range of pressures  up to 1500 °C by CO2 laser heating. The measurement on a CO2/H2O (1:1.4) mixture at 3.5 GPa shall serve as an example of our results. When the directly illuminated sample area was heated above the melting temperature of the components, only a small part around this area remains liquid due to the steep thermal gradients encountered in laser-heating experiments in a DAC. During laser-heating to about 1500 °C, a dark substance formed around the directly heated area, which disappears again when the laser spot is moved above it. However, the dark substance remained at the trailing end of the scanning movement which enabled us to deposit it in the whole sample area. The directly heated region remained clear after the laser was switched off  and the O-H stretching mode of H2O-Ice VII (3000-3400 cm−1) are greatly reduced with the appearance of these new peaks. The only compounds in the CO2-H2O binary system known to form from a reaction of its endmembers are CO2 clathrate hydrates2 clathrate hydrate can be excluded as its Raman spectrum2O and CO2 and even the recently discovered high-pressure modification was shown to decompose above a pressure of 1 GPa2O/CO2 mixtures known to exist as a solid is H2CO3. Indeed, the sharp peak at 1073 cm−1 is coincident with the intense mixed mode of the symmetric stretching vibrations νs(C–O) and νs(C=O) of crystalline H2CO3 , respectivelyip(COH) and ν(C–O) vibration in crystalline H2CO3  vibration of CO2. Also, the IR absorption spectra of both the dark and the light sample region at room temperature  revealed, that the dark product could be observed at any investigated composition  is found at slightly lower wavenumbers, the skeletal bending mode, δip(COO), δoop(COH), νas(C–O)/νas(C=O), and δip(COH) are found at higher wavenumbers than the bands from the reference spectra while νas(C=O), and νas(C(OH)2) appear essentially at the same frequency. We are confident that the position of IR absorption bands in H2CO3 is not very sensitive to temperature as the published IR absorption bands of H2CO3 from Kohl et al.et al.−1 Raman mode is sensitive to sample temperature we first synthesized the dark product as described above from a CO2/H2O (1:1.8) mixture at 4.0 GPa and then turned on the laser again at lower power to heat the center of the directly illuminated the sample area to below 700 °C. A video taken during laser heating  displays a red shift, δoop(COH), and νas(C–O)/νas(C=O), and δip(COH) blue-shift while νas(C=O) and νas(C(OH)2) do not shift significantly. Extrapolating to the low pressure at which the reference spectra were recorded, all modes observed in our experiment shift towards the published spectral features of H2CO3  initially held at 4.3 GPa as described above. After laser heating, the pressure increased to 5.2 GPa, consistent with earlier observations. The sample was then compressed to 25 GPa while the intense Raman band at 1073 cm−1 was recorded  along the thermal gradient at the edge of the directly heated area. To investigate this, a 1:1 mixture of CO2 and H2O at 2.4 GPa was resistively heated to 280 °C with a rate of 5 °C/min and the spectral evolution was monitored in situ by IR absorption spectroscopy  and νas(CO2) mode of HCO3− , no evidence for formation of aqueous H2CO3 appears to be an integral component of CO2/H2O mixtures at and above pressures of 2.4 GPa at elevated temperature. This finding can be rationalized on the following grounds. The relative abundance of H2CO3 and its dissociation products HCO3− and CO32− in an aqueous solution of CO2 is largely determined by the dielectric constant (ε) and the autodissociation constant Kw of its host solvent H2O, and both are complex functions of pressure (p) and temperature (T)23p favors increased ionization, i.e. an increase in Kw of water. As a result of this, in the carbonate system with increasing p, more ionic species (HCO3− and CO32−) are created from neutral, dissolved CO2(aq) due to the larger abundance of H+. Isobaric heating of water affects Kw and thereby the extent of ion pairing of the dissolved members of the carbonate system3− and CO32− in absence of metal ions can only mean pairing with H+, the free acid H2CO3 will be produced. Indeed, it has been observed that both ionization constants of aqueous H2CO3 decrease upon heating252SO4 was observed to increase from 3.2 to almost neutral pH when heated to 400 °C at 0.4 GPa and similar associative behavior upon heating is observed in aqueous solutions of HCl and H3PO4  and H2CO3 which is produced by the novel high-pressure technique presented herein in the investigated pressure range are likely identical.It has been shown here that H−1 Raman mode in the liquid area around the directly heated part of the sample means that solid H2CO3 does not dissolve under the high-pressure conditions of our experiment during laser-heating, even in presence of liquid water. This seems to contradict the observation that solid H2CO3 (produced during laser heating) disappears as soon as liquid water is present (during whole-cell heating). From the latter observation combined with the absence of re-precipitation of solid H2CO3 during slow cooling after whole-cell heating it can be inferred that solid H2CO3 is not thermodynamically stable in our experiment in presence of liquid water even at elevated pressure (>2.4 GPa). The formation and metastability of solid H2CO3 during laser heating must therefore be the result of a non-equilibrium process. Based on the observation of apparent of H2CO3 molecules at elevated temperatures during whole-cell heating, we suggest the following model for this non-equilibrium process. The concentration of H2CO3 molecules increases with temperature in CO2/H2O fluids above 2.4 GPa. By laser heating, a convective motion is initiated in the cell which transports mass away from the heated area, following the steep thermal gradient at its edges. In pure H2O, a polar molecule like H2CO3 would be expected to be miscible at all ratios. However, when CO2 is added to aqueous solutions, the ability to dissolve polar/ionic species is decreased due to the lower dielectric constant (ε) relative to pure H2O at the same conditions2/H2O mixture show an immiscibility gap for high concentrations of CO2 and solute with decreasing temperature while the same solute would be entirely soluble in pure H2O under the same conditions2CO3 molecules is transported to the cooler edges of the heated area faster than thermodynamic equilibrium can be re-established, H2CO3 concentrations could be high enough to make solid H2CO3 a stable phase in the CO2/H2O/H2CO3 ternary system. When the laser beam is moved across the sample, solid H2CO3 that precipitated from the hot fluid at the cooler edges of the heated area is then stabilized by the rapidly solidified CO2/H2O/H2CO3 matrix at the trailing end of the heated spot before it can dissolve by reaction with liquid water at lower temperatures. The steep thermal gradients that are apparently needed to produce solid H2CO3 in a DAC together with the apparent need for stabilization in a solid matrix make it highly unlikely that solid H2CO3 occurs as an abundant solid inside the Earth. However, the necessity of steep thermal gradients for the synthesis of solid H2CO3 also emphasizes the large effect rising temperature has on the abundance of dissolved molecular H2CO3 in deep fluids.The observation of the 1073 cm2CO3 has never been considered significant in models of COH fluids inside the Earth2CO3 is a stable species in aqueous fluids above 2.4 GPa (~ 85 km depth), and at least up to 280 °C at 3.5 GPa, and its overall stability field in aqueous fluids is far from being mapped. Some constraints can be put on the formation of H2CO3 from our experimental results, though. As a classic Brønstedt acid, its stability will depend strongly on pH with high H+ concentrations promoting H2CO3 formation. Its stability will also depend on the redox-state of the environment and is probably limited to regions where CO2 is stable, too. Furthermore, our experiments indicate that fluids present at higher temperature will contain more H2CO3 than cooler fluids.Due to its instability at ambient pressure, H2CO3 will be the simultaneous availability of free CO2 and H2O. In subduction zones, which probably show the most favorable conditions for formation of H2CO3 on Earth in terms of pressure, and temperature312 and H2O, aqueous carbon bearing fluids are created by devolatilization of the subducting slab2 with the expected peak concentration above 750 °C2 concentration in the fluid is well above the minimum pressure of 2.4 GPa identified by us for the stability of aqueous H2CO3. Production of aqueous H2CO3 could therefore be connected to subduction related volcanism.A limiting factor on the provenance of H2CO3 produced, CO2 and H2O could be significantly deprived from hot fluids through H2CO3 formation which has consequences on the geochemistry of these fluids. An apparent “masking” of H2O and CO2 in fluids at pressure above 2.4 GPa can have an influence on numerous properties of deep fluids like activity of its constituents, electrical conductivity, viscosity and density2CO3 below 2.4 GPa would be equivalent to a sudden release of CO2 and H2O which should be accounted for in models of deep fluids in this pressure region. If H2CO3 formation happens at the expense of ionic species of the carbonate equilibrium, increased solubility of carbonate minerals can be expected as compared to models neglecting H2CO3 formation2CO3 molecules in aqueous fluids above 2.4 GPa should concentrate on a quantitative description of the global carbonate equilibrium as all the above mentioned effects will strongly depend on the equilibrium concentration of H2CO3 under the respective conditions. These results will also be relevant for the geochemical modeling of large, water-rich exoplanets.Depending on the amounts of H2 (purity > 99.99%) was loaded into IIa type diamond anvil cell (DAC) containing ultrapure H2O (>18 MΩ) with the aid of a gas loader at 500 bar. The CO2/H2O ratio was determined from the relative volumes occupied by the then solid CO2 and H2O, considering the molar volumes at the respective pressure. Typically we used a gasket made of Rhenium or Platinum. The 632.8 nm line of a He-Ne-laser was used to excite the Raman spectra. Infrared (IR) measurements were conducted using a Bruker IFS-66V FTIR spectrometer equipped with a KBr beam splitter and a globar mid-infrared source. The IR beam size was adjusted according to the measured area. Spectra of the dark and the light region were recorded by shading off the part to be excluded from the light source of the spectrometer. High temperatures were achieved either by irradiation with a CO2-laser or by means of whole-cell external heating. In external heating experiments, the temperature was determined with the help of a thermocouple glued directly on one of the diamond anvils. In laser-heated experiments, temperature was determined by the glow color in the center of the heated area. While temperature estimation from the color of glowing may produce a big uncertainty, our experiments showed that crystalline H2CO3 can be synthesized in a wide temperature range as apparent from no visible glowing to a white glowing sample area. This means, that this big uncertainty in temperature has no significant effect on the validity of the results of this study. A ruby chip was inserted in the sample and the pressure determined from the peak wavelength of the R1 ruby fluorescence band.COHow to cite this article: Wang, H. et al. Stable solid and aqueous H2CO3 from CO2 and H2O at high pressure and high temperature. Sci. Rep.6, 19902; doi: 10.1038/srep19902 (2016).