Here the relaxation dynamics of chlorophyll b in the ultrafast regime have been characterized using 2D electronic spectroscopy. The comparison of experimental measurements performed at room temperature and 77 K allows the mechanisms and the dynamics of the sub-100 fs relaxation dynamics to be characterized, including spectral diffusion and fast internal conversion assisted by a specific set of vibrational modes.A thorough characterization of the early time sub-100 fs relaxation dynamics of biologically relevant chromophores is of crucial importance for a complete understanding of the mechanisms regulating the ultrafast dynamics of the relaxation processes in more complex multichromophoric light-harvesting systems. While chlorophyll  Natural light-harvesting systems are comprised of numerous pigment-protein complexes, consisting of different chromophores embedded in a protein matrix ,2. In tha (chla), the primary photoactive pigment in biological light-harvesting , whose molecular structure is reported in In this context, several efforts have been devoted to the characterization of the steady-state and time-resolved properties of chlorophyll le refs. ,7,8,9,10b in photosynthetic complexes have been widely studied in the literature. It is now ascertained that chlb expands the spectral range of chla for capturing sunlight and tunnelling it to the reaction centres [b are tuned by specific interactions between the protein backbone and the formyl group in the C7 position, whose presence distinguishes the molecular structure of chlb from chla [The biological functions of chl centres ,12,13 an centres . More rerom chla .b molecule in solution and even more scarce are the works devoted to the characterisation of its relaxation dynamics. Time-resolved techniques [b and identify possible variations with respect to chla. These works, however, targeted the dynamics beyond the first hundreds of femtoseconds (fs), studying, for example, the spectral diffusion [b molecule is part of a light-harvesting chromophore network.Fewer are the investigations on the properties of the isolated chlchniques ,17, and chniques ,19, haveiffusion  and inteb within the Q-bands, employing 2D electronic spectroscopy (2DES) with 10 fs time resolution. Chlb samples at room temperature (RT) and at 77 K were studied to assess the contribution of different dynamic mechanisms active in the two different conditions.To fill this gap, in this work we focused the attention on the sub-100 fs relaxation dynamics of chla are also highlighted, in agreement with previous reports.The results allowed essential details to be disclosed about the dynamics of spectral diffusion and the redistribution of energy to specific vibrational modes. Significant discrepancies with respect to the dynamics of chlb in a mixture ethanol:methanol 4:1 at room temperature (RT) and at 77 K. This particular mixture was selected for its capability of forming a good glass matrix at 77 K.b, analogously to the more studied chla, can be interpreted in the framework of the well-known Gouterman’s four orbital model [x (S0 → S2) and Qy (S0 → S1), with x and y indicating the polarization directions within the macrocycle plane [y and Qx, respectively. In agreement with previous investigations, the lowest energy band at 650 nm  is assigned to Qy transition, while higher energy signals are attributed to the mixing of Qy and Qx states [The electronic properties of chlal model ,21. Accole plane . At RT, x states ,22,23. Ax states , the speb at RT and at 77 K has been studied by means of 2DES in a fully non-colinear BOXCARS configuration [The ultrafast dynamics of chlguration . The lasx axis) and emission (y axis) frequencies for each value of the population time [ion time ,27,28.y  band excited by the laser, in analogy with what has already been reported for other chlorophylls [In both sets of measurements, the 2D maps are dominated by the presence of a diagonal peak that can be attributed to the ground state bleaching and stimulated emission of the Qrophylls ,10,29,30rophylls ,32.−1 and is originated by the coupling of the Qy  state with vibrational modes in the range of 200–1100 cm−1, responsible also for the broadening and the vibronic progression in the linear absorption spectrum. Ultrafast relaxation processes from higher states can also contribute at these spectral coordinates, as verified for chla [In addition to the main diagonal peak, the presence of cross peaks can also be ascertained at symmetric off-diagonal positions. In particular, the more intense cross peak below diagonal is centered at coordinates of about  cmfor chla .−1 can be identified  and rising on the two regions above and below the diagonal (blue areas), and therefore, it captures the progressive ‘rounding’ of the main diagonal peak in the 2D maps. As already reported in the literature, when considering the dynamics of monomeric chlorophylls in different solvents, time constants of hundreds of femtoseconds are typically ascribed to the spectral diffusion process ,18,30,35a in similar conditions, there seems to be no trace in this 2D-DAS of contributions due to the relaxation dynamics between the Qx and the Qy bands, manifested as a complex combination of positive and negative features at high values of excitation frequency [x→Qy relaxation could be captured in chla but not in chlb [x of the chlb molecule. Nevertheless, the availability of experimental findings coming from independent measurements acquired in different conditions and with different techniques is instead a first indication of a distinctive photophysics. A possible explanation can be found in the different degree of mixing of the Qx and Qy bands, stronger in chla than in chlb [x-Qy internal conversion in the two molecules [Differently from what was found for chlrequency . This ev in chlb . We cann in chlb , which wolecules .b in the ultrafast timescale can be achieved by analyzing the 2DES data collected at 77 K. Also for chlb at 77 K, the global analysis revealed two time constants of 60 fs and >1 ps. While the longer time constant describes a dynamic similar to that recorded at RT, the faster component has a shorter time constant. At 77 K it is expected that the spectral diffusion process is slowed down because the solvent fluctuations are dumped in the glass matrix formed at this temperature [A better picture of the relaxation dynamics of chlperature . Therefoperature ,32,40, cy transition contribute, as already pointed out in Moreover, the associated 2D-DAS exhibits a signal distribution different from the typical shape expected for spectral diffusion. Indeed, together with a decaying signal on the diagonal, it clearly shows the presence of a rising amplitude at the lower diagonal cross peak coordinates, where the vibrational modes more strongly coupled with the QThe presence of negative features below the diagonal in the ultrafast timescale is typically associated with relaxation phenomena moving population from higher to lower energy states ,31,41. TMoreover, it has been recently demonstrated that the excitation energy is quickly dumped into molecular vibrations through fast internal conversion when the modes of the bath are hindered by the low temperature .These findings suggest that, at 77 K, when the spectral diffusion due to the inertial component of solvation is hindered, the first mechanism of relaxation involves the redistribution of energy to vibrational modes. Non-radiative relaxation of excited electronic states is invariably accompanied by vibrational energy redistribution, and a number of studies have already highlighted the importance of vibrational degrees of freedom in assisting the internal conversion processes in tetrapyrrole compounds ,45,46,47x and y coordinates of the negative cross-peaks, respectively [y coordinate) of about 15,000 cm−1, corresponding to the lowest energy Qy  band and representing the final relaxed state. On the excitation axis (x coordinate) we recognize two maxima at about 16,000 and 17,000 cm−1, which suggests that vibrational relaxation mainly involves vibrational modes in the frequency range of 1000‒2000 cm−1. This finding is particularly relevant if compared with the results of simulations performed on chla and suggests that only a subset of vibrational modes, also in the case with frequencies in the range of 1400‒2000 cm−1, seem to actively aid the internal conversion process [We have already discussed the advantages of the analysis of the negative signals in the 2D-DAS for the investigation of sub-100 fs relaxation processes . The 2D-ectively . The dis process .b at RT and at 77 K. As largely documented in the literature, the beatings in the 2DES signal of isolated dyes in solution originate from vibrational coherences in the ground and excited state, and direct correspondence with Raman spectra is typically found. This also holds for chlb , which correlates the intensity of each beating component to its frequency . Figure chlb see .b response, both at RT and 77 K, is not particularly intense. This can be justified considering the low value of the Huang-Rhys factors of the vibrational modes for chlorophyll molecules [−1 [The overall amplitude of the beating in the chlolecules ,24. Noneules [−1 ,29,30,35−1 appears strongly quenched in the FSC at 77 K , whereas the amplitude of higher frequency modes is more or less conserved . This trend is somewhat expected considering that the low frequency modes are in general soft enough to be characterized by a certain degree of anharmonicity, which introduces a temperature dependence of the coupling [b.Moreover, it can be noticed that, with respect to RT, the amplitude of the vibrational modes with a frequency lower than 700 cmcoupling  and the b in an ethanol/methanol mixture has been studied by means of 2DES both at RT and 77 K. By using a global fitting analysis methodology, we could not only provide the time constants regulating the kinetics of the relaxation processes in this timescale but also get insights into the related mechanisms, thanks to the inspection of the 2D-decay associated spectra [The sub-ps dynamics of chl spectra .b, the time resolution of those experiments was not fast enough to clearly characterize the sub-100 fs dynamics [b in this timescale. The comparison with the experimental results obtained on chla solutions in similar experimental conditions [a, in chlb there is no trace of internal conversion between Qx and Qy bands in the timescale of hundreds of fs. This confirms previous assumptions based on indirect experimental findings [x-Qy mixing in chlb [The measurements at RT allowed the characterisation of the spectral diffusion processes associated with the inertial component of solvation, to which we assigned a time constant of 150 fs. Although there has been a previous work specifically focused on the investigation of spectral diffusion in chldynamics . Thus, tnditions  highlighfindings ,43 and s in chlb .b was not clear. Here, besides providing a time constant for this process, we could also verify the importance of a selected subset of vibrational modes assisting the internal conversion process.At 77 K, where the inertial motion of solvent molecules is frozen, the primary mechanism dominating the first stages of the relaxation of the excited state is an ultrafast (60 fs) redistribution of energy into vibrational modes. While it is known that the non-radiative relaxation of excited electronic states is invariably accompanied by vibrational energy redistribution, the detailed mechanism of how this is achieved in chlb in light-harvesting complexes and we expect that these findings will be revealed to be particularly important in the future interpretation of the 2DES response of biological complexes bearing chlb.The characterization of these dynamic and mechanistic details is an important piece of information towards a better understanding of the role of chlb from spinach was purchased from Sigma Aldrich and used without further purification. For the 2DES measurements at 77 K, the sample solutions were prepared by dissolving the chlb in a 4:1 ethanol-methanol mixture, until an optical density of about 0.3 on the maximum of the Q-bands was reached in a 0.5 mm cuvette. For the 2DES measurements at room temperature, chlb was dissolved in a 4:1 ethanol-methanol mixture, reaching an optical density of about 0.3 on the Q maximum in a 1 mm cuvette. We ruled out the presence of chlb aggregates, verifying that the normalized steady-state absorption spectrum does not change, lowering the concentration down to one order of magnitude.Chlb resulted in being particularly sensitive to photooxidation. Therefore, all the solutions were immediately degassed and sealed. Steady-state absorption spectra were acquired before and after each scan to control that no degradation of the sample happened during the 2DES measurements.The solutions of chl−1 (650 nm) to cover the region of the Q bands, as shown in −1. The pulse energy at the sample position was reduced to 7 nJ per pulse by a broadband half-waveplate/polarizer system.2DES measurements were performed using the setup described in . Briefly2 wedges modulated time delays between pulses. One wedge of each pair was mounted onto a translation stage that regulated the thickness of the medium crossed by the exciting beam and provided a temporal resolution of 0.07 fs. Delay times t1 (coherence time between first and second exciting pulse), t2 (population time between second and third exciting pulse) and t3  were defined.The 2DES experiment relied on the passively phase-stabilized setup, where the laser output was split into four identical phase-stable beams  in a BOXCARS geometry using a suitably designed 2D grating. Pairs of 4° CaF2. In each map, the excitation and emission frequency axes were obtained, Fourier transforming t1 and t3, respectively. The population time t2 was scanned from 0 to 1000 fs, in steps of 7.5 fs, while the coherence time t1 was scanned from 0 to 125 fs in steps of 3 fs. Each experiment was repeated at least five times to ensure reproducibility.The outcome of the experiment was a 3D array of data describing the evolution of 2D frequency-frequency correlation maps as a function of tAn Oxford Instruments OptistatDN cryostat was employed for the measurements at 77 K.Data analysis was performed exploiting the global fitting methodology described in .b in solution. The details of the mechanism regulating the excited state relaxation in this timescale were still unknown. The experiments allowed the kinetics of spectral diffusion and vibrational energy redistribution at RT and 77 K to be characterized, also highlighting significant differences with respect to the behavior of the analogous chla molecules. We expect that these findings will be of great help to untangle the complex dynamics of chlorophyll molecules in biological light-harvesting complexes.In conclusion, we characterized through 2DES the sub-100 fs relaxation dynamics of chl


In the women with type 2 diabetes and in the controls, sexual function was comparable during both phases of the cycle (p > 0.05). In the women with uncomplicated controlled type 1 diabetes, sexual function and the sexual and relationship satisfaction changed depending on the phase of the menstrual cycle with a decrease during the luteal phase. Sexual function and the quality of the sex life of premenopausal women with controlled type 2 diabetes were comparable during both the follicular and the luteal phases. Sexual function in menstruating women with controlled type 2 diabetes decreased with age and a worsening mood.Sexual dysfunction is more common in women with diabetes than in women without diabetes. The aim of the study was to determine sexual function and the level of the quality of sex life in premenopausal women with controlled, uncomplicated type 1 and type 2 diabetes taking into account the stages of the menstrual cycle and mood level. The study included 163 women with type 1 and type 2 diabetes and 115 controls without diabetes. Questionnaire studies were conducted using the following surveys: Demographic and Clinical Data Survey, Female Sexual Function Index, Sexual Quality of Life—Female, and Beck Depression Inventory. Both phases of the menstrual cycle—follicular and luteal—were included. It was shown that, in women with type 1 diabetes, sexual function decreased during the luteal phase in comparison with the follicular phase ( Diabetes is a common chronic disease that is classified as a civilization disease. A distinction is made between type 1 diabetes (T1DM), which is associated with an insulin deficiency, and type 2 diabetes (T2DM), which primarily results from insulin resistance. This disease leads to many chronic complications, which include sexual dysfunction in both men and women . Men witThe assessment of the sexual functions of menstruating and fertile diabetic women during the follicular and luteal phases seems to be interesting and important from the point of view of clinical sexology. According to the literature review, only one study has been devoted to this issue so far. It was published in 2006 and included women with T1DM. It was shown that these women had decreased sexual function and increased sexual distress compared with control subjects during the luteal, but not the follicular, phase of the menstrual cycle .Due to the small amount of research and the complexity of sexual problems, as well as cultural and methodological difficulties, women’s sexual dysfunction still remains a silent complication. Sexuality, its multidimensionality, and individual perception make determining the predictive factors of sexual disorders in women quite difficult and not very accurate ,17,18,19The aim of the study was to determine the level of sexual activity and the level of the quality of sex life in premenopausal women with controlled, uncomplicated type 1 and type 2 diabetes taking into account both stages of the menstrual cycle and mood level.Cohort studies were conducted in 206 patients with diabetes (91 with T1DM and 115 with T2DM) and 133 nondiabetic women in the control groups. Because some of the women refused to participate in the study or because their questionnaires were incomplete, only 70 women with T1DM aged 22.9 ± 2.0 (mean ± SD) years (Group I) and 93 women with T2DM aged 39.1 ± 6.5 years were qualified for the study (Group II), in addition to 58 controls (Group CI)—corresponding to the age of Group I and 57 controls (Group CII))—corresponding to the age of Group II. Taking into account the phase of the menstrual cycle, Group I included 32 patients in the follicular phase (Group IA) and 38 patients in the luteal phase (Group IB), and Group II included 39 patients in the follicular phase (Group IIA) and 54 patients in the luteal phase (Group IIA) IIB), while, in the CI Group, there were 31 women in the follicular phase (CIA Group) and 27 women in the luteal phase (CIB Group) and, in the CII Group, there were 32 women in the follicular phase (CIIA Group) and 25 women in the luteal phase (CIIB Group).The criteria for inclusion in the study were age from 18 to 45 years, duration of diabetes at least 1 year after diagnosis, glycated hemoglobin (HbA1c) <7%, sexual activity with at least two sessions of intercourse a week, regular menstruation, persistence in heterosexual relationships, and giving informed consent to participate in the research. The study excluded people with cancer, endocrine gland diseases, alcoholism, inflammation within the last 4 months, and the use of immunosuppressive and anti-inflammatory drugs, glucocorticoids, psychotropic drugs, or oral contraceptives. The T1DM patients were treated with insulin and followed the recommended diet. However, for the women with T2DM, the treatment consisted of compliance with the diet and the use of oral antidiabetic drugs from the sulfonylurea and biguanidine groups, although several patients were also given insulin. All of the individuals that were included in the study were patients of the Clinic Practice Group of Doctors in Kaczyce Silesian Province. Patients with T1DM and T2DM were recruited for participation when they visited their doctor to monitor their health in terms of their carbohydrate balance and blood pressure. The women from the control groups did not have any chronic diseases and did not take any medication. The participants were recruited by their doctor during routine periodic medical examinations. All subjects were informed about the study protocol. Participants voluntarily agreed to participate in the study and all signed informed consent. The research was conducted from June 2017 until December 2019.In all examined women, fasting blood glucose level was determined. The HbA1c level was determined in examined patients only. Systolic and diastolic blood pressure was measured and body mass index (BMI) was calculated. Subsequently, questionnaire studies were conducted using the following surveys: Demographic and Clinical Data Survey, Female Sexual Function Index (FSFI), Sexual Quality of Life—Female (SQoL-F), and Beck Depression Inventory (BDI). It was recommended that the answers to the questions in FSFI, SQoL-F, and BDI cover the last 7 days. The questionnaire studies were conducted in the second half of the follicular or luteal phase. The questionnaires were self-administered and fulfilled independently by each participant included in the study at the clinic without any possible influence from medical staff.The survey included parameters such as age, education, place of residence, marital status, professional activity, stimulants being used, duration of diabetes, comorbidities, and medications being taken.The FSFI questionnaire, which was developed by Rosen et al. , consistThe SQoL-F questionnaire was developed by Symonds et al. . It consThe BDI is a 21-point screening questionnaire that is used to assess the severity of mood disorder (depression) symptoms. The scale consists of 21 questions that score from 0 to 3 points. The results that can be obtained in the BDI range from 0 to 63. The BDI is a questionnaire that has been standardized and validated to Polish conditions, which is repeatedly used in studies to assess mood disorders . Before t-test was used for the data with normal distribution, while, for the data without a normal distribution, the Mann–Whitney U test was used, and, for the qualitative data, a series of χ2 tests were used . When examining the impact of the different factors on the level of the quality of a participant’s sex life and sexual function, the multiple stepwise regression method was used, which resulted in linear relationships being obtained (the result was the equation of a straight line with many parameters). To compute the effect of two covariate factors such as group and phase of the menstrual cycle on FSFI, SQoL-F, and BDI, the MANOVA.RM (repeated measures) package was used, where the available function provides the Wald-type statistic. This package also contains the simCI function which allows multivariate post hoc comparisons. Tukey’s honestly significant difference test was used for multiple comparisons in this article. The study assumed a 0.05% significance level.Statistical calculations were done using the Statistica 13 software. Normality tests were performed using the Shapiro–Wilk W-test. The results are presented for the data with a normal distribution using the mean and standard deviation, while those for the data without a normal distribution are presented for the median and first and third quartiles. The qualitative data are presented in terms of numbers and percentages. In order to determine the homogeneity of the groups, the Student’s p > 0.05; p < 0.05) in the patients during the luteal phase than during the follicular phase   of the SQoL-F were significantly lower during the luteal phase than in the follicular phase ( > 0.05) .p > 0.05; Using a MANOVA in the patients with T2DM and the controls, there were no significant differences between the values in the domains of FSFI, the SQoL-F factors, and the BDI on the phases of the menstrual cycle . The model was statistically significant and explained 42.9% of the observed variability in the dependent variable (p < 0.0001). In the patients with T2DM, the total FSFI score decreased with age (p = 0.002) and decreased as their mood deteriorated (p < 0.001). The model was statistically significant and explained 35.8% of the observed variability in the dependent variable , decreased with age (p = 0.004), and increased in patients with higher total FSFI (p < 0.001). The model was statistically significant and explained 38.9% of the observed variability in the dependent variable . The model was statistically significant and explained 44.3% of the observed variability in the dependent variable  of the women with T1DM was significantly lower during the luteal phase . In the nondiabetic control group, the results of sexual function that were obtained during both phases of the menstrual cycle were comparable. In the available literature, only one publication was found that concerned the sexuality test in patients with T1DM, which took into account the phases of the menstrual cycle [It was demonstrated that, in the patients with uncomplicated T1DM, the level of sexual activity in all of the subjects using the FSFI domains  was lower during the luteal phase than it was during the follicular phase  of the patients with T1DM was lower during the luteal phase than during the follicular phase. The demonstrated reduced sexual and relationship satisfaction in the luteal phase compared to the follicular phase may be related to the observed increase in discomfort or pain at sexual penetration during the luteal phase. In addition, the lower factor 2 value of SQoL-F in the luteal phase in T1DM coincides with the satisfaction domain value in the FSFI. A multiple regression analysis showed that total SQoL-F of these women was lower during the luteal phase, decreased with age, and increased in patients with higher total FSFI score.The changes in sexual function and the quality of sexual life seemed to depend mainly on diabetes itself as an independent risk factor for sexual dysfunction because, in the examined group of women, there were no cases with complications of this disease or any other accompanying diseases, and no drugs other than insulin were used. Similarly, Flotynska et al.  suggesteAfter considering the menstrual phase, the patients with controlled, uncomplicated T2DM had comparable levels of sexual function in all of the FSFI domains that were tested during the follicular and luteal phases. In the available literature, no work was found that involved studies of sexual function in patients with T2DM during the phases of the menstrual cycle. In this study, we showed that patients with T2DM had decreased sexual function in older women and with a lower level of the mood.Consistent with the level of sexual function, the quality of sexual life was also not different in patients with T2DM depending on the phase of the menstrual cycle. It was found that the level of the quality of the sex life of these patients had a positive correlation with total FSFI score. Celik et al.  also shoOn the basis of our studies, it is not possible to explain the observed differences in sexual function levels in women with T1DM and T2DM depending on the cycle phase. It can only be assumed that hormonal factors, mainly ovarian steroids which modulate a woman’s sexual activity , and nonOur research had some limitations. Firstly, sexual function was not tested in the same women, both in the follicular and in the luteal phases, which resulted, among other reasons, from the lack of consent to conduct repeated tests; this did not allow observing longitudinal changes in sexual function and in SQoL-F in women with T1DM and T2DM and in the control groups. Secondly, in the studied women, the hormonal parameters such as estradiol, follicle-stimulating hormone, luteinizing hormone, progesterone, prolactin, and androgens in the blood serum in the luteal and follicular phases were not determined, which could shed light on the mechanism explaining the difference in the level of sexual function depending on the cycle phase in T1DM and the absence of that difference in T2DM. Thirdly, the number of women in the individual groups was relatively small; this was related to the difficulty in selecting homogeneous groups in terms of sexual activity, regular menstruation and its phase, the absence of diabetes complications, and evenness of the disease and age . Fourthly, the patients were recruited only from the diabetes outpatient clinic, which means that they are not fully representative of the entire population of women with diabetes. Fifthly, partner relationships and mutual emotional and sexual expressions were not studied, which could have been important in assessing the sexuality of the women that were surveyed.In regularly menstruating women with uncomplicated, controlled T1DM, sexual function and sexual and relationship satisfaction changed depending on the phase of the menstrual cycle with a decrease during the luteal phase. Sexual function and the quality of sex life of premenopausal women with controlled T2DM were comparable during both the follicular and the luteal phases. Sexual function in the menstruating women with controlled T2DM decreased with age and a worsening mood.The research was approved by the Bioethical Commission of the Beskid Medical Chamber in Bielsko-Biała at the meeting on 16 February 2017 (consent No. 2017/02/16/8).All of the procedures that were performed in the study involving human participants were in accordance with the ethical standards of the committee and with the 1964 Declaration of Helsinki.


Recently, the CALPHAD method and phase-field method have been recognized as promising approaches to realize phase stability and microstructure developments in engineering materials. Thus, we applied these methods to understand the thermodynamic feature of the grain boundary phase and the microstructural developments in Nd-Fe-B hard magnets. The results are as follows. (1) The liquid phase is a promising phase for covering the Nd  Therefore, we reached the conclusion that the liquid phase is a promising phase as a grain boundary phase of Nd hard magnets.As the experimental measurements of interfacial energy on common metals, such as Al, Cu, and Fe, provide y region ,12. Thisy region  .1 grains. It is important to understand the metastable phase equilibria between T1 phase and liquid phase at 873 K. 1 (Nd2Fe14B phase) and L (liquid phase), were considered [1 phase and a liquid phase. Note that there exits the metastable equilibrium between the T1 phase and the Nd-rich liquid phase at 873 K. We can easily know the composition of the metastable liquid phase from The practical thermal treatment to optimize the coercivity of the Nd magnet is annealing around 873 K, which promotes the formation of a thin liquid phase at the grain boundary region of Tnsidered . The thi1 + L) two-phase region, which will support the hypothesis that the grain boundary phase is related to the metastable liquid phase. Since the volume fraction of the T1 phase is dominant in an Nd magnet, the average alloy composition of Nd must be located beside the stoichiometric composition of the T1 phase in the (T1 + L) region. Therefore, the tie line end of the liquid phase changes drastically depending on the average concentration of Nd around the grain boundary region. The oxidation reaction of Nd is inevitable in rare-earth magnets [The colored symbols in the phase diagram indicate the compositions of the grain boundary phase , which h magnets . Thus, a magnets .3.21 phase and a grain boundary phase. Experimental measurements elucidate that the grain boundary phase often takes an amorphous sate, with a width of ~3 nm [Although the metastable phase diagram is useful as mentioned above, further modification is possible. The composition of the grain boundary phase was calculated by modifying the theory of the phase-field method based on the concept of the grain-boundary-phase model proposed by Hillert ,13,16. Fof ~3 nm . In geneof ~3 nm ,13. The 1 phase, and subscript 1 grains with different crystal orientations from each other. 1 phase and the grain boundary phase, which are the functions of local composition 1 phases with different orientation numbers, respectively. V is the volume of material, and B is a positive constant that regulates the contribution of the penalty term. The composition of the grain boundary phase is determined from the steady-state composition profile obtained after the long-term phase-field simulation. The numerical values used in this simulation are Here, in refs. . Note th1 phase is key for developing high-performance Nd hard magnets.It is interesting to note that the Nd concentration in the grain boundary phase decreased drastically from 100 to 30 at% with a small change in the average Nd composition from 15 to 12 at%. The Nd composition in the grain boundary phase is significantly influenced even by a slight change in the Nd average composition. The equilibrium Nd composition in the grain boundary phase is ~80 at%, as per the calculation from the metastable phase diagram . HoweverThe reason why the Nd composition of the grain boundary phase exceeded the Nd composition calculated in the metastable phase diagram can be easily understood if we imagine the parallel tangential construction to two Gibbs energy curves . With reIn addition, the calculation method utilized in this section is equivalent to the Lagrange multiplier method mathematically. When we ignore the gradient energy terms in 4.1 phase, Nd solid phase, and liquid phase, were performed based on the phase-field method [1 phase. Furthermore, the effect of Cu addition on the morphology of the microstructure is discussed [In this section, two-dimensional simulations of the morphological microstructure changes of the as-sintered Nd hard magnet during isothermal aging, which includes the Td method ; here, tiscussed .Note that kinetic parameters, such as the diffusion coefficient and the mobility of the phase field, were considered constant in this study refer to . Therefo4.11 phase and the Nd solid phase, respectively, and the gray lines represent the grain boundary of T1 grains. The morphology of polycrystalline microstructure of 1 phase and Nd solid phase of the initial microstructure  is stabilized relatively. diagram . By incrAccording to the calculation theory of the phase-field method, interfacial energy is defined as a sum of the gradient energy and the Gibbs energy at the interface region. The gradient energy coefficient is the same value in the simulations of 5.1 phase on the morphological changes of the liquid-phase microstructure are discussed in this section by using the phase-field simulation. To understand the microstructure changes concisely, we employed simple calculation conditions here, i.e. only two phases, liquid phase and T1 phase, were considered and the Nd solid phase was excluded in this section.In this paper, since we are interested in the morphological stability of the liquid-phase microstructure, the effects of the phase separation in the liquid phase and the grain size of the T5.11 grains, we referred to the microstructures observed in the anisotropic Nd-Fe-B hot-deformed magnets [ magnets .Figure 11 polycrystalline microstructure. This is because of the phase separation in the liquid phase, and the effect of phase separation on the morphological stability of the liquid phase, which covers the T1 grains, was analyzed in detail. 1) and Nd-Cu-rich liquid phase (L2), respectively. As the phase separation of the liquid phase has been reported in the thermodynamic assessment of the Fe-Cu-Nd phase diagram [1 and L2, which is dependent on the Cu alloy composition, calculated using the CALPHAD method. The phase fraction of the L2 phase gradually increases with increasing Cu composition, whereas the phase fraction of the L1 phase gradually decreases, then the total phase fraction of the liquid phases is not greatly affected by the Cu composition. For increasing the total phase fraction of the liquid phases, it requires the simultaneous increase both of Nd and Cu contents in the alloy composition.It is recognized that the components, Nd and Cu, are mainly partitioned to the liquid phase with aging. When we focus on the local compositions of Nd and Cu in  diagram , the liq2 phase is mainly detected at the triple junction region of T1 grains, whereas the L1 phase is observed at the grain boundary region between T1 grains. It should be emphasized that this layout of each liquid phase may slow down the coarsening of each liquid phase. If we imagine the coarsening process of the L1 phase, the L1 phase should move over the L2 phase; in other words, the movements of the L1 and L2 phases will interfere with one another during coarsening. The phase separation of the liquid phase can contribute to stabilize the characteristic microstructural morphology (uniform coating of the T1 grains by the liquid phase) temporally.In the microstructure shown in 2 phase) mainly settles at the triple junction points of the grain boundary region of T1 grains as in the case of 2 phase becomes relatively larger compared with the case of In addition, to clarify the effect of the position of liquid phase nuclei, the simulation in which we changed the position of the nuclei was performed as shown in 2 phase preferentially occupies the triple junction points of T1 grains is currently under consideration, one possible explanation may be as follows: Since the Gibbs energy of L2 phase is lower than that of L1 phase because Nd and Cu compositions in L2 phase are higher than those of L1 phase. As the energy at the triple junction points of the grain boundary is high, if the L2 phase occupies these regions, the interfacial energy will be lowered relative to the case of the L1 phase. Because the phase-field method automatically finds the low energy state, it can be understood that the preferential occupation of the L2 phase at the triple junction points of T1 grains is calculated.Although the reason why the L5.21 grains was changed, and the simple hexagonal polycrystalline microstructure is employed for simplicity. The grain size of the T1 phase in (a) is larger than that in (b). Other calculation conditions are the same as those shown in 1 grains in 1 grains is small, the total grain boundary area in the material becomes large. Therefore, a large amount of the liquid phase is required to cover the T1 grains uniformly. Note that the suitable solute composition of alloys and optimum thermal process conditions, which results in the ideal microstructure (T1 grains are uniformly covered with a grain boundary phase), depending on the grain size and shape of the T1 phase. The small grain size of the T1 phase is attractive to improve the coercivity of Nd hard magnets [1 phase.Almost all of the T magnets ,4. The o6.In this study, we focused on the grain boundary phase and investigated the thermodynamic stability and the microstructure developments by using computational thermodynamics and microstructure simulations, which were performed using the CALPHAD method and phase-field method, respectively. The conclusions obtained are as follows:2Fe14B grains uniformly, which is helpful for attaining high coercivity. It is important to recognize that this concept is supported by the high thermodynamic stability of the T1 phase.The liquid phase is a promising phase for covering the NdThe metastable phase diagram of the Fe-Nd-B ternary system suggests that the tie line end of the liquid phase changes drastically depending on the average Nd composition. The oxidation reaction of Nd is inevitable in rare-earth magnets; thus, a slight decrease in the Nd concentration in the local position of the microstructure results in a large concentration change of Nd in the metastable liquid phase.Nd concentration in the grain boundary phase can reach 100 at% if the volume fraction of the grain boundary phase is constrained, even if the maximum Nd concentration determined from the metastable phase diagram is less than 100 at%. This provides flexibility to control the concentration of the grain boundary phase from the viewpoint of microstructures.Phase-field simulations are useful for understanding the morphological changes in the microstructures, including the grain boundary phase. In particular, the effect of Cu addition on the microstructural morphology is reasonably modeled based on the phase-field method.1 phase.The morphology of the liquid phase can be controlled using phase separation in the liquid phase and the grain size of the T


The study accounts for potentially spatial confounding factors related to urbanization that may have influenced the spreading of SARS-CoV-2 and related COVID-19 mortality. Our epidemiological analysis uses geographical information  and negative binomial regression to assess whether both ambient PM2.5 concentration and excess mortality have a similar spatial distribution. Our analysis suggests a positive association of ambient PM2.5 concentration on excess mortality in Northern Italy related to the COVID-19 epidemic. Our estimates suggest that a one-unit increase in PM2.5 concentration (µg/m3) is associated with a 9%  increase in COVID-19 related mortality.Long-term exposure to ambient air pollutant concentrations is known to cause chronic lung inflammation, a condition that may promote increased severity of COVID-19 syndrome caused by the novel coronavirus (SARS-CoV-2). In this paper, we empirically investigate the ecologic association between long-term concentrations of area-level fine particulate matter (PM With more than twelve million confirmed COVID-19 cases and more than 550 thousand related deaths globally as of the beginning of July 2020,2.5 include residential heating , transport, agriculture, background , and other . The second is the location in the orographic “bowl” of the Po Valley, an extension of flat river lands enclosed between the Alps and Apennines mountains, which causes the stagnation of pollutants due to low ventilation  are also the most densely populated and heavily industrialized and thereby the most heavily polluted regions of Italy. These four regions together host 39% of the national population,3 for the averaging period of a calendar year, the Po valley shows values consistently near or above the threshold. These values often range in the 25–30 μg/m3 interval with peaks of > 30 μg/m3, which in Europe are only matched in Southern Poland and other smaller Eastern European clusters . Cole et al.  of monitoring station data related to the years 2015–2019.Mortality data are collected at the municipality level for the period January-April 2020. Given that mortality data are not disaggregated by mortality cause, death counts are measured as the difference from the last five-years mean to reflect the abnormal number of deaths caused by the spreading of the pandemic. Since PM2.5 concentrations and a series of control variables that may plausibly affect both PM2.5 concentration and mortality, including population density; the spatial concentration of the industrial manufacturing sites; climatic conditions observed during the first quarter of 2020; and the demographic composition of the municipal population among others. In addition, we consider spatial heterogeneity in the distribution of the number of deaths related to regional and local unobservable factors. We account for region-specific effects because regions, in Italy, are the administrative units in charge of managing the health systems and the measures taken to trace and contrast the spreading of the pandemic varied greatly among even contiguous regions. We also account for local effects common to functionally linked clusters of municipalities . We deem this part of the identification strategy crucial because the relationship between PM2.5 and COVID-19 mortality may be confounded by several other factors, some of which were not observable or measurable, but are nevertheless intrinsically related to the geographical location of the observed units.We estimate a negative binomial model of excessive deaths on historical PMThe remainder of the paper is organized as follows. The next section introduces the empirical strategy and describes the dataset. The results are presented and discussed in section three, considering the total number of (excess) deaths. Section four draws the conclusions and highlights the limitation of the study and the indications for future research.Our analysis is restricted to the study area of Northern Italy Fig. , which eExDeaths) and use this metric as the dependent variable in our statistical model. Figure Working under the assumption that COVID-19 deaths are underestimated in Italy, the choice is made in this paper to use the total deaths from the official registries, accordingly, and to scale the analysis at the municipality level, the smallest administrative units, to have a more granular representation of the spatial dimension of the phenomenon. Since we are interested in excess deaths, we take the difference between the number of deaths in the period January 1—April 30, 2020, and the average number of deaths in the same period of the previous 5 years  total population as the offset while The variable is assumed to follow a Negative Binomial distribution, a generalization of the Poisson distribution that avoids the restrictive mean–variance equality of the latter, and is modelled as follows:2.5 data is the European Environmental Agency’s (EEA) air monitoring database, which is provided to EEA by the Institute for Environmental Protection and Research (ISPRA). ISPRA conducts ground-level air measurements of PM2.5 air concentrations (µg/m3) collected at 268 monitoring sites throughout Italy. Specifically, we use the EEA’s E1a and E2a datasets, which are primary validated assessment data and primary up-to-date assessment data reported by the European Member States, respectively. Although the measurements come both in hourly and daily averaging formats, we work with daily values and use them to obtain yearly aggregates for the years 2015, 2016, 2017, 2018, and 2019. However, because model (1) does not include a time component, we further compute a six-year averaging time to obtain a metric of long-term (chronic) PM2.5 concentration levels throughout different spatial units of Northern Italy. The number of 6 years for the reference period is sufficiently long to account for long-term exposure while being not too long to be affected by the mobility of people among municipalities, and it is in line with existing literature assessing long-term effects of PM exposure  we include both the regional fixed effects and the LLS random effects.2.5 exposure in a municipality. Underlying socioeconomic conditions can also play a role in COVID-19 related mortality  was 25 deaths, while it grew to 34 in 2020. That results in an average excess death of 9, with standard deviation four times as larger . The introduction of the LLS random effects appears to solve the issue of autocorrelation.In model 2, the regional fixed effects coefficients are statistically significant. They indicate that other things being equal, the number of deaths in municipalities in Lombardy and Emilia Romagna has been systematically higher compared to base category2.5 and show how the expected number of deaths by region varies at different concentration levels in Fig. Based on the estimates of model 4, we compute the expected value of excess deaths conditional on covariates (taken at the average level) in the average city for varying levels of PM2.5 metric used in our study, we explored the influence that other alternate PM2.5 metrics may have on the direction and magnitude of the observed associations. Figure 2.5 models result in IRRs trending in the same direction, the point estimates for IRRs are lower than our primary analysis which was based on a combination of ground monitoring and kriging. The lower IRR point estimates are unsurprising because the underlying data for the alternate PM2.5 metrics do not have the same temporal coverage as the ground-level monitoring data (2015–2019). This lack of temporal coverage contributes to non-differential exposure misclassification, which, in turn, would lead to suppressing effect estimates towards the null. Despite this, it is encouraging to find that regardless of the PM2.5 metric used, the direction of the observed associations remains, and so does statistical significance.For robustness check of the PMAs previously anticipated, we re-estimate model (4) using different specifications of the Kriging interpolator. In particular, we first relax the mean-stationarity assumption of Ordinary Kriging by modelling the mean function of the process through both a linear and a quadratic trend in latitude and longitude. Next, we replace the simple Exponential function with a Spherical model and a more flexible Matérn kernel with the characteristic parameter set at 3/2 (to preserve mean-square differentiability). All these specifications still assume covariance stationarity. Figure 2.5 is always of the hypothesized direction and statistically different from zero. Precisely and consistently with previous results for the original SARS-Coronavirus during the 2003 outbreak  and nearly 9% (model 4—lowest rate). The 95% confidence interval for the point estimate in model 4 lies between roughly 6% and 12%. Our findings fall in line with both Wu et al.  and the remaining covariates, we observe no effect related to population density or income or the extent of industrial areas in the municipality. Likewise, there is no evidence suggesting significant links between the share of non-EU residents, the female to male ratio (which disappears after we incorporate the random effects), and the level of education (proxy by the percentage of university students) on the dependent variable of interest. On the other hand, our results suggest a negative association between temperatures and mortality due to COVID-19. Finally, as expected, we find that municipalities with higher shares of the population aged 65 or more have been most affected. The distance from the closest airport, a measure of relational connectedness that also proxy for the exposure to the contagion process, deserves a last comment. We find that municipalities closer to an airport experience a higher number of deaths in excess. We speculate that the result could be related to a higher likelihood for these municipalities to become clusters of contagion in the initial phase of the pandemic, but a causal link cannot be inferred based on our result ad the topic needs more research to be addressed adequately.3 of PM10  on the one hand, the dynamics of the spread of the contagion requires further information to be investigated such as its genesis, the type of virus, and setting of the first outbreak; (2) the effects of the lockdown changed  the contagion in an asymmetric way. In addition to this, of course, there are other elements that should be investigated, such as additional variables about health data, mobility, and so forth.Our results reinforce the need to adopt environmental policies that would not only reduce the impact of pollution on the health of citizens and workers but would contribute to smooth the negative effects of a (future) pandemics, avoiding collapses of health systems. Indeed, recent studies show that in addition to chronic lung inflammation, environmental air pollutant concentrations can exacerbate the effects of increasingly frequent one-shot systemic shocks, which in turn are also caused by environmental factors. In this regard, sustainable and decarbonization policies such as the Green New Deal, conceived as long-term policies, should be accelerated.


The purpose of the present study was to examine the extrusion-cooking process of cereal blends with addition of hatchery waste (HW). The effect of HW addition on the physical properties and chemical composition of the extrudates was examined. The share of the HW in blends with corn meal was variable in the range of 5–30%. The study was conducted using a counter-rotating twin-screw extruder . Increase in the content of the HW from 5 to 30% reduced the expansion ratio, pellet durability index, water absorption index, and water solubility index of the extrudates. The microstructure of the extrudates with HW addition is non-homogeneous; the areas with densely packed and adherent granules, interwoven with fibrous structures, can be observed. Increase in the share of HW leads to a lowering of the levels of crude fiber and total dietary fiber in the extrudates. Moreover, a significant increase in the content of protein, crude fat, and mineral elements such as calcium, sodium, magnesium, and iron was observed. Similar results were obtained by other authors [Bacillus stearothermophilus FS 1518) were sterilized at an extrusion temperature of 182°C and a material retention time of 45 s [In recent years, the constantly growing demand for poultry products, which led to an intensive development of the hatchery industry and the associated production of hatchery waste (HW), has given rise to a serious environmental problem ,2. An im authors . Extrusi authors . The twiThe purpose of the present study was to examine the possibility of processing HW with the method of extrusion and the effect of the addition rate regarding the waste component on the physical properties and chemical composition of the extrudates.22.1The materials used in this study were HW, acquired from the poultry hatchery Malec , and corn meal . The chemical composition of the materials used in the study is presented in 2.2The study was conducted using a counter-rotating twin-screw extruder  with conical screws and an L:D ratio of 12:1. The screw speed applied was 75 rpm and die diameters were 3 mm × 6 mm. Retention time of the mass in the extruder chamber was 90 s ± 10. The profile of temperature distribution in the extrusion-cooker barrel was 120/140/180/180/130°C. The process parameters applied in the study and the composition of mixtures were determined from pilot experiments. Only such parameter ranges that guaranteed correct and stable run of the process were adopted.2.3Ma is the mass of the extrudates retained on the screen after tumbling (g) and Mb is the mass of the extrudates retained on the screen before tumbling (g). The water absorption index (WAI) and water solubility index (WSI) of the extrudates were assayed with the centrifuge AACC method 88-04 [Expansion ratio (ER) was calculated as the ratio of the cross-sectional area of the extrudates to the cross-sectional area of the die. Pellet durability index (PDI) of the extrudates was determined following ASAE Method No. S269.4 . Approxiod 88-04 .2.4The microstructure of extrudates was studied in a sample with 20% HW content. The sample was sliced into fragments that were then glued with silver paste onto specimen circles and sprayed with carbon and gold in a vacuum sprayer-type JEE 4X . Microscopy analyses were carried out via an electron microscope of the type JSM 5200 .2.5N × 6.25. The content of the detergent fractions of dietary fiber in the samples was found to conform to that of the method developed by Van Soest [MC was determined using the AACC method 44-15A . The saman Soest ,22. The Enzymatic method was applied to determine the content of total dietary fiber (TDF), insoluble dietary fiber (IDF), and soluble dietary fiber (SDF) fractions. In the determination of enzymatic fiber, Megazyme enzymes and methodological procedures were employed according to AOAC (methods 991.43 and 985.29) and AACC  ,23. The 2.6P < 0.05). Regression models describing the correlation between physical properties of extrudates and percentage share of HW were developed. The statistical analysis of the results was performed using the program SAS 9.1.3 .Chemical analyses were carried out in three replications, and physical properties were analyzed in five replications. Mean values and pooled standard error of the means were calculated. The significance of differences among the results was determined using the Duncan test  for their respective feeds. This means that different quality standards are used to evaluate the feed products . ProductR2 = 0.83):Increase in the content of the waste component led to a decrease in the degree of ER. The above correlation can be described using the formula for the regression (R. Seker  claims tR2 = 0.94):The PDI represents an important parameter in the evaluation of extrudates and it expresses the resistance of products to crumbling. Ayadi et al.  and SamuIt can be observed that the mechanical strength of the products is reduced on increasing the content of HW, which may be a result of changes to the microstructure. The non-homogeneity of the structure of extrudates with 20% of HW content  was mostR2 = 0.92):R2 = 0.82):WSI is an especially important parameter in the case of fish feed. The products of this type should be characterized by high water stability and possible low values of WSI . Increaszedzicki  reportedAccording to many authors, the WAI of extruded products is positively correlated with the degree of damage to starch granules . A higheThe chemical composition and nutritional value of HW highly varied and depend on the hatching rates of poultry and on the variable amounts of shells, eggs, embryos, and culled chicks ,8,12. ThThe HW used in the study was a very rich source of minerals . Their cCompared to corn meal, HW is a material that is richer in proteins and fat . The incThe content and fractional composition of dietary fiber in feeds for animals have an effect on the rate of intestinal passage, digestion, and absorption of nutrients . In this4The technology of twin-screw extrusion can find an application in the utilization of HW and responsible disposal of this kind of waste product in animal feed production. The addition of HW to corn meal in amounts not exceeding 30% and the application of blend moisture at the level of 28% and extrusion temperature of 120/140/180/180/130°C permitted a stable run of the process and to achieve products with moisture not exceeding 9%. An increase in the share of HW in the extrudates resulted in a higher content of crude fat, protein, and minerals, especially calcium. A higher content of HW in raw material resulted in decrease of the ER, PDI, WAI, and WSI in the extrudate.


Besides, the MLS can withstand larger bending deformation. When the MLS was bent to 180 degrees, neither macro-cracks in the outer side of the bending parts nor interfacial delamination can be found.In this research, multilayered steel (MLS), which is composed of middle-carbon martensite steel, high-carbon martensite steel, and a pure Ni thin layer was obtained by the accumulative roll-bonding method. The microstructure and mechanical properties of the MLS were investigated by scanning electron microscopy (SEM), Vickers microhardness, tensile, and bending tests. In-situ SEM tensile tests were used to observe the crack initiation and propagation processes during the tensile loading. The results show that the ultimate tensile strength and bending strength of the MLS can reach 946 MPa and 3153 MPa, and the maximum elongation can reach 18%, which is related to the better combined quality of the interface. The middle and larger martensite layer (ML) becomes the weakest link of tensile fracture and interfacial delamination of the MLS during the tensile processes, because there are lots of large hard blocks Cr Multilayered metal composites consisting of alternating ductile and brittle materials show a unique combination of high fracture toughness and high tensile strength, so they have been widely used in structural applications. Some studies have massively concentrated on the mechanical properties of multilayered metal composites, such as deformation, bending toughness, and fracture toughness ,2,3,4,5.Multilayered metal composites can be performed by various manufacturing methods, such as accumulative rolling bonding (ARB), explosive welding and rolling, diffusion joining, casting rolling, etc. Martensitic steel has a higher tensile strength and lower tensile elongation; however, austenitic steel has a higher tensile elongation and lower tensile strength. Several studies have concentrated on obtaining a multilayered steel by combining martensitic steel with higher strength and austenitic steel with higher tensile elongation ,11,12,13In the previous works, more studies have concentrated on the manufacturing and properties of three-layer composite plates or multilayer composite plates only by two materials. Based on the difference of the performance requirements, single martensite or austenite stainless steels are usually chosen to obtain three-layer composite plates or multilayer composite plates by combining martensitic steel with higher strength and austenitic steel with higher tensile elongation. However, it is very rare to use more materials to fabricate and study multilayered composite plates. Therefore, the microstructure and fracture behavior of a special multilayered steel with three materials must be investigated. In this study, three different materials are selected for the development of composite plate used in cutting tools. For a middle layer with higher hardness and wear resistance, high carbon martensitic steel is chosen. For the two sides with higher plastic elongation and good strength, the previous works have only used single martensitic stainless steel or a single austenitic stainless steel, depending on the performance requirements. Here, the composite layers including a medium carbon martensitic layer and pure Ni layer are chosen as the two sides, i.e., the composite plate is composed of a middle high carbon martensitic layer and two composite layers at two sides, each composite layer including 19 medium carbon martensitic layers and 19 pure Ni layers, as shown in In this study, the multilayered steel that is composed of middle-carbon martensite steel, high-carbon martensite steel, and a pure Ni thin layer was obtained by the accumulative roll-bonding method. In the Introduction, the multilayered steel has been introduced. The thickness of the total multilayered steel (MLS) is 2.25 mm. The chemical composition of each layer in the MLS is shown in −3 s−1. After the tensile experiments, the strength, ductility, and fracture modes of the composite plates can be obtained. Tensile experiments were conducted for tensile specimens as shown in Bending experiments were performed using the bending specimens in The Vickers microhardness was measured using an automatic hardness tester. Since the thickness of each layer was only 32.4 μm, a small load of 25 g and the dwell time of 15 s were used to ensure the size of indents smaller than 15 μm. The measured result is obtained by the average value of nine indents in the center of each layer.−5s−1) was used to obtain the deformation, crack propagation, and fracture processes. After fracture, the SEM-observed surface and fracture surface were directly compared. The fracture features were also observed and analyzed by SEM.Especially, for in situ tensile specimens as shown in To further determine the fracture mechanisms and demonstrate the relationships between the properties and microstructures, the microstructures were grinded, polished, and etched by the etchant reagent with 4 g of picric acid + 5 mL hydrochloric acid + 100 mL ethyl alcohol for 30 seconds, and then, they were observed and analyzed by SEM.To further clearly characterize the phase and misorientation, an EBSD technique was used in a SEM operated at 20 kV. A 160 μm × 160 μm EBSD area scan was performed using a hexagonal grid with a step size of 0.28 um. 1 denotes the multiple martensitic layer in the two sides. 1 and the pure Ni thin layer. The middle and larger martensite layer (ML) in 23C6, and Cr7C3 carbides distributed in the matrix. The composite multilayers distributed in two sides in 1) and 19 pure Ni thin layers. The thickness of each ML1 layer and each Ni layer is 32.4 μm and 7.6 μm, respectively. So, the MLS in this paper is composed of a middle ML layer with a thickness of 575 um and two composite layers including 19 ML1 and 19 Ni layers. On the two sides of MLS, the thicker ML1 and thinner Ni layer were used. To reveal the distribution of the elements between the middle ML layer and the composite layer including the ML1 and Ni layers, line scanning distribution along the black line OA in 1. Although the C content obtained by EDS is not true, the trend of the change can be seen in 1 in 23C6, and Cr7C3 carbides distributed in the matrix. Cr23C6 and Cr7C3 carbides in ML and ML1 can be determined by EDS point analysis in 1). In the interfaces, the exist of large angle boundaries will contribute to the slip of the boundaries and the matrix near carbides, which will decrease the stress concentration near carbides, further improving the compatible deformation of grains and boundaries near carbides. The fraction of large-angle boundaries (larger than 15 degrees) reaches 52.5%, which is larger than the 42.4% of small-angle boundaries (lower than 15 degrees); thus, the plasticity can be improved.1 layer. It is attributed to the large block Cr23C6 distributed in the ML layer. The hardness of the large block Cr23C6 can reach 1400 HV.To characterize the microstructure of MLS, the hardness was also measured. The hardness of the ML layer can reach 385.2 HV, which is higher than 310 HV in the ML1 and Ni layer. It can be found that delamination can be found in the interface between the middle large ML layer and the Ni layer. It is related to the different hardness. This is because there are lots of large hard block Cr23C6 phases distributed in the ML layer near the Ni layer, and the thickness of the middle ML layer reaches 575 μm. The middle higher hardness ML layer with a larger thickness of 575 μm makes large strain incompatibility in the interface between the ML layer and the Ni layer. However, in the interface between the ML1 layer and the Ni layer in two sides of MLS, amounts of deformation and diffusion can be produced at the interface, and local brittle carbide cracking and plastic dimples are all produced in the interface in 1 layer. From bb is 3.8 KN, and the bending strength can be calculated by the following Formula (1). In Formula (1), σbb is the bending strength, Fbb is the maximum bending load, Ls is the loading span, w is the factor of specimen’s cross-section, and w = bh2/6 . By using an Fbb of 3.8 KN, loading span (Ls) of 28 mm, width of the bending specimen (b) of 10 mm, and thickness of the bending specimen (h) of 2.25 mm, the average bending strength σbb can be calculated as 3153 MPa.When the MLS bending specimen was bent to 136 degrees, a macro-bending feature is shown in The detailed bending processes will be analyzed by micro-observed features in 23C6 phase. However, in the 1 far from the maximum bending moment of the specimen. 1 and the Ni layer on both sides of MLS, no crack can be found, only plastic deformation traces, while some slip lines occur in different degrees. It shows that the flexural capacity of the specimen is still relatively satisfied, although in the middle harder ML layer, amounts of brittle block carbides were cracked. It should be attributed to the large brittle carbide particles due to high carbon.To further reveal deformation behavior after bending to 136 degrees, the MLS specimen was also bent to 180 degrees, as shown in To observe the crack initiation and propagation processes during the tensile loading, in-situ SEM tensile tests were done. Moreover, besides the cracking processes of the carbides being observed, the slip deformation of the Ni layer near the fracture is also observed in 1 layer. At the moment of fracture, the delamination is produced at the interface between the Ni layer and middle ML. The delamination phenomena can be obviously presented in the fracture surface of an in-situ tensile specimen, as shown in 1 or finer carbides in ML. It may be because the brittleness of larger block carbides is larger than that of finer carbides in ML and ML1. The hardness of the larger block carbide can reaches 1400 HV, which directly contributes to the larger brittle of ML. So, if the larger block carbides can be controlled to finer size, the tensile ductility and the bending deflection will be improved.From 1 and Ni layer, various fracture modes and cracking behaviors were shown in According to Ref. ,16, the 1 layers. Currently, it can also be related to the larger thickness of the middle ML. It can be identified in 1 layers.In this paper, the microstructure and mechanical properties of multilayered steel (MLS) are evaluated by SEM, EBSD, tensile tests, a bending test, and an in-situ tensile test. The obtained results are summarized as follows.23C6 and Cr7C3 carbides distributed in the matrix. The multilayer composite layer in the two sides of MLS is alternately composed of 19 middle carbon martensile layers (ML1) and 19 pure Ni thin layers distributed in two sides of the middle ML. ML1 is composed of a ferrite base metal and Cr23C6 and Cr7C3 carbides distributed in the matrix. The microstructure of the Ni layer is single austenite; besides, some diffusion of element Ni, Fe, Cr in the bonding interface can be found.(1) A special MLS can be manufactured using three different materials by the accumulative roll-bonding method. It is composed of the middle and thicker high-carbon martensite layer and the multilayer composite layers at two sides. The middle and thicker martensite layer is composed of high-carbon martensite steel, of which the microstructure is composed of ferrite base metal and Cr(2) The MLS can reach the ultimate tensile strength of 946 MPa and the maximum tensile elongation of 18%. Bending tests were conducted to investigate the formability of MLS. When the MLS was bent to 136 degrees, the bending strength can reach 3153 MPa, and the deflection can reach 22 mm. Even though the specimen was bent to 180 degrees, no macro-crack still can be found, only plastic deformation traces, and some slip lines occur in different degrees.23C6) of the ML. With the further increase of applied load, the Cr23C6 block phase is snapped and the number of cracks increases; finally, the cracks connect and the specimens fracture. (3) During tensile processes, the cracks were firstly initiated in block carbide particles  In the whole fracture process, both the Ni layer and the metal on both sides (MLS) have good plasticity, and the plastic deformation plays a crucial role in the plasticity of the MLS. The middle and larger martensite layer (ML) becomes the weakest link of tensile fracture and causes the interfacial delamination of the MLS. The cracking of the large block carbides and the dimple in the matrix dominates the fracture surface of the middle ML layer. However, the dimple fracture dominates the fracture in the Ni layer and ML


Titania can exist in amorphous form or in three different crystalline conformations: anatase, rutile and brookite. Few studies have characterized TiO2 covering the surface of dental implants from the crystalline point of view. The aim of the present study was to characterize the evolution of the TiO2 layer following different surface treatments from a crystallographic point of view. Commercially pure titanium and Ti-6Al-4V implants subjected to different surface treatments were analyzed by Raman spectroscopy to evaluate the crystalline conformation of titania. The surface treatments evaluated were: machining, sandblasting, sandblasting and etching and sandblasting, etching and anodization. The anodizing treatment evaluated in this study allowed to obtain anatase on commercially pure titanium implants without altering the morphological characteristics of the surface.The osseointegration of titanium implants is allowed by the TiO Titimplants ,8,9.2 layer has a thickness of between 3 and 40 nm on dental implants [The TiOimplants .2 formed during normal ambient conditions on Ti is amorphous if there is no additional treatment. In addition to the amorphous phase, three different crystalline polymorphs of titania exist naturally, namely anatase, rutile, and brookite, with the last being rarely reported [The native TiOreported ,12,13.Among the three conformations, rutile is thermodynamically the more stable phase at ambient temperature and pressure , but anaSoft chemistry method, hydrothermal process, and the sol–gel route allow to obtain titania . Since tUsually, the transformation from the amorphous phase to anatase occurs between 400 and 550 °C, from anatase to rutile between 600 and 1100 °C ,16,17. N2 have been extensively studied [Titania is well known for catalytic, photocatalytic and nonlinear optics properties ,20,21. W studied ,23, few  studied . Apatite studied ,26,27,28 studied . Anatase studied ,30. More studied ,33,34,35 studied . While  studied , there a studied ,38.Thermal treatment and anodization (anodic oxidation) are recognized as capable of producing a layer of crystalline titania on the surface of CP and TA ,30,39,40Atmospheric pressure plasmas have demonstrated to effectively reduce carbon contamination and enhance free energy of implant surfaces ,44,45.2 layer of TA (Ti-6Al-4V) implants [2. Furthermore, the sandblasting treatment with corundum caused a contamination of the final surface with traces of Al2O3.Recently, our group analyzed the effect of different surface treatments on the crystallinity of the TiOimplants . The stuRaman spectroscopy (RS) is a well-established method to monitor titania formation and its crystal habit due to the great sensitivity to structural changes and due to the higher Raman efficiency of Ti-based oxides. In addition, RS is non-invasive and non-destructive, and thus it is widely used in different basic and applied research fields involving chemically and mechanically processed functional oxides ,48,49,502 layer from the crystallographic point of view of implants obtained starting from different materials, i.e., CP titanium (grade IV) and TA (Ti-6Al-4V) and subjected to different surface treatments. The structural analyses by Raman spectroscopy has been corroborated by complementary analyses using UV and SEM microscopies. SEM-EDX measurements have been also performed allowing an elemental quantification as a confirmation of the structural information derived by Raman inspection. Thus, with this approach, we obtain an estimation of the oxide layer and of Al2O3 contamination.The present study, therefore, was aimed to monitor with micro-Raman spectroscopy the evolution of the TiO2 induced by manufacturing phases, experimental implants made of CP and TA were specifically produced by FMD Medical Devices  for the present study.To characterize the crystallographic transformation of TiOThe compositions of the pristine materials according to factory datasheets  and to tFor the observations, screw-shaped implants with threads 5.5 mm wide and 14 mm long were produced. All the implants were obtained with manufacturing procedures commonly used in the production of commercial implants and were produced starting from the same batch of TA and CP.Each implant characterized by a single surface was produced in duplicate. Each implant was obtained through a procedure, consisting of: (i) machining (milling) of the raw material in the presence of a lubricant, (ii) ultrasonic cleaning with solvents, that was the same for all and then subjected to the final surface treatment. After the surface treatment, all implants were subjected to packaging in glass jars under laminar flow hood and dry heat sterilization for 3 h at 170 °C.The samples differed only in the final surface treatment. The surface treatments evaluated were: machining, sandblasting, sandblasting and etching and sandblasting, etching and anodization.The sandblasting was carried out with Al2O3 particles with an average size of 180–200 μm. The etching was carried out for 15 s with an HF (0.5%) and HNO3 (64.5%) solution. The anodization was carried out with direct current anodization for 15 s at 60 V. Each surface treatment was conducted on CP and TA implants. The surface treatments evaluated in this study were chosen as they are commonly used for the production of commercially available implants.2 and the power density on the samples of the 632.8 nm laser spot was about 5 × 105 W/cm2, (ii) particular care was paid to the measurement of background signals for reliable subtractions for each sample; (iii) the best fitting procedures were performed by using Lorentzian curve as fitting function, and (iv) typical integration times were about 2–3 min and the mapping measurements required approximately 2 h of counting.An Olympus HS BX40  microscope equipped with a LabRAM Dilor  spectrometer were used to conduct micro-Raman measurements at room temperature. The working parameters for Raman spectrometry as well the experimental procedures and data best-fitting procedures were the same used in our previous study . Here, wAll the implants were analyzed in two different regions, i.e., on the top of the screw and on the middle of the screw. These two regions were chosen to evaluate whether the surface treatments  were in any way influenced by the presence of the threads of the screw.All the samples were observed under the optical microscope  on the top of the screw with three different magnifications, i.e., 100×, 200× and 500× equipped with digital camera Infinity1 ; then were observed under UV fluorescence microscope  with 500× magnification, with an Olympus UC30  digital camera.In a second measuring session, all the listed samples were analyzed by a Scanning Electron Microscope  providing also EDS elemental analyses. For A1 and T1 samples only a micrograph at 500x magnification was collected, as they are the starting samples not yet processed with a surface treatment. For all the other samples a first image at 160× magnification was collected, then a second one at 500× magnification and after that micrographs were recorded in the same area at increasing magnifications .The SEM images were collected both using secondary electrons (SE) and the back scattered electrons (BSE) one. The first provides for morphology of the sample surface with an image contrast depending on the roughness and orientation of the surface, while the second allows to distinguish between areas with different chemical composition, due to the sensitivity to the atomic weight of the specimen elements ,52.2 layers was derived by calculating the ratio between the percentage of surface O and Al obtained through EDS analysis.An estimation of the thicknesses of the TiOThe whole set of investigated samples, with proper codes, as well as indications about pristine materials and treatments is reported in The optical and UV microscopy allowed to analyze the homogeneity of the surfaces. From the morphological point of view, at this spatial resolution degree, no any particular differences have been observed. The UV microscopy revealed the presence of photoluminescent signal, associated to the corundum contamination, from all the sandblasted samples. Anyway, all the surfaces subjected to sandblasting had the same appearance both under UV light and optical microscopy .−1, indicating the formation of a very disordered TiO2 layer. Even the anodization treatment (TA4) provokes a very small increase of the Raman signal of the A1g mode of Anatase. The same happens when the TA-based screw is further processed by plasma treatment (TA4p). These results from TA implants are the confirmation of what we found in previous observations [2O3-blasting and HNO3/HF etching, presents a well-defined and intense mode at 145 cm−1 and weaker but measurable additional Raman modes at around 400, 510, and 635 cm−1. This set of Raman signals represents the Raman fingerprint of anatase TiO2. The subsequent anodization treatment, CP4 sample, provokes an increase in the whole Raman yield. The previously reported signal is higher and very well defined indicating a net increase of the crystalline order, which in any case is clearly already present in CP3 sample, i.e., the sample not yet anodized. The crystalline order in processed CP-based screws is missing in processed TA-based implants. For all the samples, the energy region till 1800 cm−1 was monitored. −1.The spectra are the result of different experimental runs in different regions of the top of the screws and from the middle. The Raman signals from TA screws are characterized by a very low Raman yield with a weak peak detectable at around 143 cmrvations . Differe−1 with a doublet structure. This is the unmistakable fluorescence signal of the Cr3+ ion excited by the red light of HeNe laser. As well-known Chromium impurities are usually present in the corundum habit. On the other hand, the fact that Cr3+ luminescence is correlated with the presence of corundum is confirmed looking at the lower energy region where the Raman signal from the corundum system Al2O3 is observed at around 416 cm−1. A strong signal is peaked at 1390 cm3+ luminescence signal has a very high cross-section when enter as substituent of Al ions in the octahedral coordination sites of the crystal lattice of corundum. Indeed, it is well known that even Cr impurity amount of the order of few ppm can give photoluminescence signals quite stronger than those observed by us [One has to observe that the Cred by us .2 layers in different screws.On the bases of single point measurements and looking at sample regions where no photoluminescence was present, we have performed different Raman mapping tests in order to monitor the homogeneity of anatase TiO−1. Two representative cases are reported in 2 phase and in turn represents an indication of the thicknesses of anatase titania formed on the screws. In The mapping has been obtained using as the intensity marker the integrated intensity of the anatase mode at 145 cmImportant complementary information has been obtained by SEM measurements. In It is possible to appreciate a smooth and bright surface with the presence of grooves due to the turning and smoothing process of the surface.2O3 showed a similar appearance regardless of further treatments  and/or anodization, in each previous study experimental parameters were completely different. In particular the material used for sandblasting, the nature of acids, the sequence of use, the difference in applied electrical potential, the treatment times are variable which have a significant effect on the final result [2 on the surface of TA implants, but this finding does not conflict with the fact that other treatments have produced anatase or different surface morphologies.The results of this study confirm the absence of crystalline TiOreported . The datl result ,37. The For example, a recent study evaluated in vivo in the rabbit model Ti6Al4V implants treated by a thermal process to obtain a layer of anatase on the surface. The histological and histomorphometric results of that study showed a significant increase in bone–implant contact after treatment to obtain a surface layer of anatase .2O3 had a surface morphology equivalent and similar to the analogous surfaces reported in the literature [In this study all surfaces subjected to sandblasting with Alterature ,37.2O3 residues on the final surface after sandblasting with corundum. The experimental surface treatments used in this study, and in particular the acid etching treatment, are not able to completely decontaminate the implant surface. Other studies reported this event [As previously observed , the resis event ,42.Furthermore, even the applied anodizing treatment did not change the surface morphology of the implant but only the crystallographic conformation of the titania.Confirming previous studies, the anodizing treatment carried out on CP implants determined the growth of anatase. Unlike those previously published , the anoFurthermore, the results of our study indicate that anatase can also occur with less elaborate surface treatments than anodization, and at low temperatures.The evolution of the surface is given by an increase in the thickness of oxide on CP and TA implants and by crystallization on CP implants.2 surface layer during the manufacturing process, for each sample, the ratio O/Al has been calculated by using the atomic percentage values provided by EDS measurements.In order to evaluate the possible formation of an ordered TiO2O3) micrograins as consequence of the sandblasting.The measured Oxygen percentage could have dual source. It could be due to (i) the formation of a Titanium oxide surface layer, as a product of the manufacturing process, or to (ii) the presence of residual corundum (AlTo better clarify this, the EDS analyzes have been carried out with 160× magnification in order to average as much as possible the presence of corundum micro-grains in the irradiated volume. Moreover, for each sample, the EDS measures have been focused on a single corundum grain, thanks to higher magnification, in order to evaluate the Oxygen percentage in the only corundum phase.2 on the surface of dental implants. In fact, it is known that the presence of anatase and crystalline TiO2 can have biological effects, for example on osseointegration and antibacterial properties, but it is not known whether these effects, in turn, have a significant clinical effect. The results of this study show that it is possible to obtain a layer of anatase on implant surfaces without altering their surface morphology. Future studies should evaluate the biological significance of the presence of anatase by comparing morphologically identical surfaces differing only for the presence of anatase on the surface. This aspect will be the subject of future investigation.At this point it is important to underline that the Raman measurements evidenced a short-term stability of the anatase layer for CP3 and CP4 samples, as derived for repetition of the spectra in a few weeks. This stability accounts for mechanical manipulation and laser irradiation. Of course it will be highly important to evaluate long-term mechanical, chemical and phase stability in particular in view of the evaluation of the biological effects of the presence of crystalline TiO2O3-blasting and HNO3/HF etching produce a well ordered anatase layer, further increased by the anodization treatment. On the contrary a disordered oxide layer was obtained from implants made of titanium alloy, even for anodized samples. The amount of oxide has been also corroborated and confirmed by the SEM-EDS analyses. It is important to note that the treatments used in this study allowed the formation of anatase also in the absence of high temperatures and without anodization. The observed oxide layer formation highlighted by Raman and EDS spectra is accompanied by a substantial invariance of the surface morphology of the implants.In this work we, have studied by Raman microscopy the crystalline ordering of implant surfaces depending on starting material and surface machining and treatments commonly used for dental implants. Regardless of starting material, titanium-alloy or commercially pure titanium, the increase in the complexity of the surface treatments determines an increase in the thickness of titania on the surface of the implants. However, only for CP implant did the treatment by Al