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An ideal hydrogen storage material is a key topic in efficient hydrogen energy utilization. We have explored several potential hydrogen storage materials Mg 3 XH 8 (X = Ca, Sc, Ti, V, Cr, Mn) by first-principles calculations. The studied materials all belong to lightweight hydrogen storage materials. The normal phonon dispersion spectrum indicates, without regard to other materials, at least Mg 3 TiH 8 and Mg 3 VH 8 are completely stable in dynamics, which is also demonstrated by elastic stability criteria. The elastic properties show that they are all ductile materials with the applicable potential in flexible fields. Besides, they are gapless and metallic in band structures. With the correction of Hubbard values, all transition metal based Mg 3 XH 8 materials are magnetic materials with magnetic moments of 0.34 μ B for Mg 3 ScH 8 , and 2.14 μ B for Mg 3 TiH 8 , 1.29 μ B for Mg 3 TiH 8 , 2.65 μ B for Mg 3 TiH 8 and 4.86 μ B for Mg 3 MnH 8 , respectively. Whereas Mg 3 CrH 8 and Mg 3 MnH 8 exhibit highly light active in infrared and visible region. Considering overall structural stability, excellent mechanical properties, high gravimetric hydrogen density (6.21% and 6.07%) and moderate hydrogen desorption temperature (∼350 K), Mg 3 TiH 8 and Mg 3 VH 8 are considered as the candidates for promising hydrogen storage materials. Besides, Due to half-metallic nature, they are also potential in spin electronic devices. [Display omitted] • First-principles calculations to investigate Mg 3 XH 8 materials for hydrogen storage. • Mg 3 TiH 8 and Mg 3 VH 8 are found to be dynamically stable and ductile. • Mg 3 TiH 8 and Mg 3 VH 8 are half-metallic and promising in spin electronic devices. • Mg 3 TiH 8 and Mg 3 VH 8 both possess high gravimetric hydrogen density (>6.0%). • The hydrogen desorption temperatures of Mg 3 TiH 8 and Mg 3 VH 8 are around 350 K. [ABSTRACT FROM AUTHOR]

In order to search for good hydrogen storage materials, the structural, optoelectronic and hydrogen storage properties of double perovskites KNaMg 2 F 6-x H x and KNaAe 2 H 6 (Ae = Be, Mg, Ca) have been studied by first-principles calculations based on density functional theory in this paper. All the negative formation energies demonstrate the thermodynamic stability of these materials. Except for KNaBe 2 H 6 , the rest of the materials are wide-band gap semiconductors or insulators. The gravimetric storage capacity of KNaMg 2 F 6-x H x increases with the introduction of hydrogen and reaches a maximum of 5.19 wt% at x = 6. Meanwhile, the KNaBe 2 H 6 exhibits the best storage capacity of 8.57%. The favorable desorption temperature for stable KNaMg 2 H 6 material is 470.4 K, which is feasible in actual application. As the concentration of hydrogen increases, the electronic bandgap of KNaMg 2 F 6-x H x decreases gradually due to its electron conduction band moving to a lower energy range. The bond population analysis indicates that there is a mixture of ionic and covalent bonds in the studied materials. These materials are all ultraviolet absorber, and a red-shift can be observed in the absorption edge due to the variation of bandgap. • Double perovskites are introduced as the novel hydrogen storage materials. • Hydrogen substitution improves the stability and optoelectronic performance of double perovskites. • All materials exhibit wide band gaps as well as high ultraviolet absorption. • Stable KNaMg 2 H 6 material possesses ideal desorption temperature of 470.4 K and gravimetric storage capacity of 5.19 wt%. [ABSTRACT FROM AUTHOR]

The effect of lithium doping on novel double perovskite materials for hydrogen storage has been investigated through first-principles calculation. The lithium doping would cause phase change due to different crystal symmetry. Based on tolerance factors, cohesive energy and Born-Huang criteria, the materials are all stable. The analysis of hydrogen storage properties indicates that lithium doping can both improve the gravimetric storage capacity to 4.41% and 5.08%, and decrease the desorption temperature to 348.7 K and 325.0 K for K 2 LiScH 6 and K 2 LiAlH 6 , respectively. And to a certain extent, the introduction of lithium improves the optoelectronic properties especially the photoresponse in ultraviolet region, which demonstrates the applicable potential in photocatalysis. The results are consistent with the wide bandgap values. Our study provides some reference for further experimental studies of double perovskites in hydrogen storage materials. • Lithium is introduced into double perovskites to improve hydrogen storage characteristics. • These materials exhibit an optimal storage capacity of 5.08% and desorption temperature of 325.0 K. • The variations of accurate optoelectronic property are obtained by hybrid HSE06 functional. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Ba 6 CCh 4 (Ch = S, Se, Te) are stable materials with hexagonal structures. • The Ba 6 CCh 4 (Ch = S, Se, Te) anti-perovskites have direct band structures. • The materials have high light absorption coefficients in UV–Vis-IR region. The structural, electronic and optical properties of anti-perovskites Ba 6 CCh 4 (Ch = S, Se, Te) are investigated by first-principles calculations. The perovskites are stable hexagonal materials because of negative formation energy and positive phonon spectra. The materials have brittle characteristics from elastic properties. Besides, the elastic Born-Huang stability criteria confirm the structure stability. They are direct band perovskites with bandgap values of 1.554 eV, 1.311 eV and 1.517 eV for Ba 6 CS 4 , Ba 6 CSe 4 and Ba 6 CTe 4 , respectively. The VBM is composed mainly by C-p and Ba-d states, while and CBM is due to contributions of Ba-d states. The chalcogen elements have little contribution to both conduction and valence bands. The high light absorption in UV–Vis-IR region compared with AM1.5 irradiance confirm the great prospects in solar energy utilization including photovoltaic. [ABSTRACT FROM AUTHOR]

The physical properties of three potential colbat-containing perovskites are studied through first principles calculation. The structural analysis reveals that the Cs 2 InCoI 6 and Cs 2 AgCoI 6 are ductile and potential in flexible devices. The negative formation energies indicate that all these perovskite syntheses are practicable in experiment. However, the results of tolerance factors and phonon spectra are presented against the structural dynamic stability of pure cubic phase of Cs 2 TlCoI 6 and Cs 2 AgCoI 6 and there may be lattice distortion. The band gaps of Cs 2 InCoI 6 , Cs 2 TlCoI 6 and Cs 2 AgCoI 6 are 0.833 eV, 1.713 eV and 0.783 eV, respectively, all values are within the ideal range for semiconductors that applied in optoelectronic devices. They all exhibit broad-spectrum light absorption in ultraviolet and visible region, and the absorption coefficient of Cs 2 InCoI 6 even maintains a value above 10000 cm−1 at wavelength of 1400 nm. Among them, Cs 2 InCoI 6 perovskite has direct band structure, smaller carrier effective mass than that of CsPbI 3 and broad solar absorption characteristics, which is considered as a promising candidate material for optoelectronic devices. • The physical properties of three novel cobalt perovskites are studied. • Cs 2 TlCoI 6 is found to be stable in tetragonal rather than cubic phase thus a phase transition may take place. • Cubic Cs 2 InCoI 6 is found to be a stable perovskite with broadband light absorption. • Pressure-induced optical properties and structural stabilities of Cs2InCoI6 are studied. [ABSTRACT FROM AUTHOR]

In this paper, we consider two weighted estimators to improve estimation efficiency in quantile regression with longitudinal data. The first estimator is from weighted quantile regression, and the second estimator is from weighted composite quantile regression, where the weights in the second estimator are from the first estimator. Different from earlier literature, our weights are quantile adaptive, which borrow information from the intra-subject correlation of the conditional quantile scores, rather than the conditional least squares scores. The weight for each subject is obtained from smoothed empirical likelihood quantile estimator, where quadratic inference function method is used to model the inverse of the correlation matrix of the conditional quantile scores. Under some regularity conditions, we prove that the weighted estimators are more efficient than the standard quantile regression estimators with equal weights. We conduct a simulation study and a real data analysis to evaluate the performance of the proposed approach. [ABSTRACT FROM AUTHOR]

Laser communication plays an important role in a broad range of fields. In need of the faster data rate of the flourished information communication, we propose a hybrid scheme that utilizes photon's polarization property integrated with on-off keying modulation to improve the data rate. The theoretical analysis indicates that this polarization property of photon is a useful dimension to combine with other schemes to obtain a higher performance, even in the heavy atmosphere turbulence, showing its potential in optic communication in the future. [ABSTRACT FROM AUTHOR]

Abstract: Background: Since its introduction into North America in 1999, West Nile virus (WNV) has spread rapidly across United States (US). Objective: To genetically analyze WNV isolates from US blood donors during 2002–2005. Study design: Full-length nucleotide (NT) sequences of WNV isolates from 23 US volunteer blood donors of different geographic areas from 2002 to 2005 were determined and analyzed. Results: Results indicated an overall lack of geographic pattern to WNV in US. Analyses of the viral genetic diversity demonstrated that the WNV evolved at approximately five NT substitutions and 0.8 amino acid (AA) mutations per genome per year. Comparison of the functional sequences of WNV genome showed a higher evolution rate in the coding region than in the non-coding region. Furthermore, a greater diversity was observed in the nonstructural proteins as compared to the structural proteins. Sequence alignment analysis revealed that the rapid spread of WNV in US was accompanied by the establishment of a dominant genetic variant with 11 conserved NT mutations. Conclusions: The establishment of a dominant genotype across US and the displacement and possible extinction of earlier progenitor genotypes appears to have resulted from the accumulation and fixation of 11 nucleotide mutations throughout the coding region of WNV genome. [Copyright &y& Elsevier]

In this paper, we study the key factors that impact on power systems resilience under severe weather-induced disruptions from three dimensions: the extrinsic disruptions, the intrinsic capacities of a system and the effectiveness of recovery. Using 12 years of historical blackout data from 2007 to 2018 in the U.S., we apply various group selection and bi-level selection methods to identify the key predictor groups as well as factors within-group that affect power system resilience. After deleting the predictors which are fully or highly correlated with others, we split the remaining 39 candidate predictors into 8 natural groups and consider the number of customers affected and the recovery time as response variables. To ensure stability of the selection process, we adopt the random subsampling method to rank the importance of the groups and key predictors. It is found that the disruption types from the extrinsic disruptions dimension have a significant impact on the resilience of power systems, especially for the hurricanes with high scales. From the intrinsic capabilities dimension, the demographic group has a large impact on the number of customers affected. The number of customers affected tends to be large in highly urbanized areas with large population. From the effectiveness of recovery dimension, the group of economics is top selected for the recovery time. It is found that the power system tends to be more resilient with a better economic health. Feature selection under quantile regression is also conducted as the histograms show that the distributions of the responses are skewed and heavy-tailed. It is found that the recovery time is also greatly affected by the investment on the compliance and enforcement program from the North American Electric Reliability Corporation. In summary, our analysis provides interesting insights for understanding power system resilience and developing strategies to enhance the resilience. • Look into extrinsic disruptions, intrinsic capacities and effectiveness of recovery. • Analyse 12 years of historical blackout data from 2007 to 2018 in the U.S.. • Apply group selection and bi-level selection to identify key groups and predictors. • Use the random subsampling to rank the importance of the groups and predictors. • Provide insights for understanding and enhancing power system resilience. [ABSTRACT FROM AUTHOR]

Abstract: Background: Starting in 1999, the West Nile virus (WNV) epidemic represents the largest outbreak of arboviral encephalitis ever recorded in the U.S. The effective means to determine an infection are detection of viral nucleic acid and/or viral specific immunoglobulin, IgM and/or IgG. Objective: To develop a highly sensitive and specific TaqMan RT-PCR assay for the detection and quantification of WNV RNA of lineage 1 and lineage 2. Study design: A TaqMan RT-PCR primer–probe was designed to perfectly match target sequences of all sequenced WNV strains and isolates, which added a layer of protection against false-negative results due to strain variability. In addition, the inclusion of a low level RNA internal control (IC) in the assay increased the precision and accuracy of the assay. Results: By optimizing the RNA preparation procedure for increased WNV RNA recovery, together with optimizing the primer–probe and TaqMan conditions for improved amplification efficiency, we developed a highly sensitive assay with the detection limit of 10 copies/mL. To evaluate the assay, we tested plasma samples from 12 transfusion-transmitted implicated cases in 2002 and from 68 positive blood donors in 2003. All tested specimens were WNV positive. The viral load of 68 positive blood donor samples collected in 2003 ranged from 10 copies/mL to 67,000 copies/mL with a mean of 8100 copies/mL. Furthermore, high sensitivity of the assay was achieved without compromising specificity. All 100 routine donor samples tested negative. Conclusions: The assay results demonstrate that our in-house TaqMan RT-PCR procedure can detect and quantify WNV RNA of lineage1 and lineage 2 in human plasma with high sensitivity and specificity. [Copyright &y& Elsevier]

Diabetes mellitus (DM) is a widespread metabolic disease presenting with various complications, including spermatogenic dysfunction. However, the underlying mechanisms are still unclear. Ferroptosis, a novel type of programmed cell death, is associated with much metabolic diseases. Here, we investigated the role of ferroptosis in spermatogenic dysfunction of streptozotocin (STZ)-induced type 1 diabetic mice (diabetic mice), high glucose (HG)-treated GC-2 cells (HG cells) as well as testicular tissues of diabetic patients. We found an accumulation of iron, elevated malondialdehyde level and reduced glutathione level in the testis tissues of diabetic mice and HG cells. Histological examination showed a decrease in spermatogenic cells and spermatids within the seminiferous tubules as well as mitochondrial shrinkage in the testis tissues of diabetic mice. Ferrostatin-1 (Fer-1), the inhibitor of ferroptosis, mitigated ferroptosis-associated iron overload, lipid peroxidation accumulation and spermatogenic dysfunction of diabetic mice. Furthermore, we observed a downregulation of GPX4, FTL and SLC7A11 in diabetic mice and HG cells. Fer-1 treatment and GPX4 overexpression counteracted the effects of HG on cell viability, reactive oxygen species, lipid peroxidation and glutathione via inhibition of ferroptosis. Moreover, we found an elevation of ferroptosis in testicular tissues of diabetic patients. Taken together, our results identify the crucial role of ferroptosis in diabetic spermatogenic dysfunction and ferroptosis may be a promising therapeutic target to improve spermatogenesis in diabetic patients. [Display omitted] • Increased ferroptosis caused spermatogenic dysfunction in type 1 diabetic mice and patients. • Ferrostatin-1 treatment alleviated spermatogenic dysfunction in diabetic mice. • Ferrostatin-1 treatment and GPX4 overexpression attenuated ferroptosis in high glucose treated GC-2 cells. • Inhibition of ferroptosis may be a potential therapy to alleviate diabetic male infertility. [ABSTRACT FROM AUTHOR]

[Display omitted] • The materials are stable double perovskites by tolerance factor and formation energy. • The studied materials are all direct and quasi-direct semiconductors. • Tl 2 PdBr 6 is regarded as a potential candidate for single junction solar absorber. The structural stability, energy band and photoelectric properties of vacancy- ordered double halide perovskites A 2 BX 6 (A = In, Tl; B = Pd, Pt; X = Cl, Br, I) are studied in detail by first principles in this paper. The results show that these materials have suitable tolerance factor, negative formation energy and good phonon spectrum, which indicates that they have structural stability. These materials are all semiconductors with band gaps varying from 0.328 eV and 3.238 eV via HSE06 hybrid functional. All the materials have direct or quasi-direct band structures, which are beneficial for carrier generation. These materials have small reflectance and large absorption coefficients for visible - infrared light, especially in the ultraviolet region where the absorption coefficient is very large. The absorption coefficient of the material is obviously improved when the anion X changes from Cl to Br to I. Making a comprehensive analysis of absorption coefficient, transmittance and bandgap values, Tl 2 PdBr 6 is regarded as a potential candidate for solar absorber in single junction solar cells, while In 2 PtCl 6 and Tl 2 PtCl 6 may be applied in transparent conductor films. [ABSTRACT FROM AUTHOR]

[Display omitted] • The geometric structures and vibration attribution analysis of 6MP, C60 and C59-X (X = Si, Al, Ti) were optimized by DFT B3LYP/6-311G(d,p) method. • The geometric structures of C60-6MP and C59-X-6MP(X = Si, Al, Ti) complexes were optimized by DFT B3LYP-D3(BJ)/6-311G(d,p) method. • The binding energies of C60-6MP and C59-X-6MP(X = Si, Al, Ti) complexes were calculated using DFT M06-2X-D3/6-311+G(2d,p) method. • The solvation energies of C60-6MP and C59-X-6MP(X = Si, Al, Ti) complexes were calculated using DFT M05-2X/ 6-31G (d) method. • Use Multiwfn software to do topological analysis of Atoms-in-molecules (AIM) of the complexs. C60 fullerenes are often used as drug carriers because of their unique geometric structure and electronic properties. To investigate whether C60 fullerenes can be used as a drug delivery system for 6-mercaptopurine (6MP), we calculated the binding energy and the solvation energy of C60-6MP complexe using density functional theory (DFT). In order to explore whether doping atoms with different properties can change the adsorption performance of 6MP on C60, we replaced one carbon atom of C60 with three different atoms of Si, Al and Ti. The results showed that the binding energy of C59-X-6MP(X = Si, Al, Ti) complexes are higher than C60-6MP complexe, and the solvation energy are lower, which indicating that doping can improve the drug delivery characteristics of C60 to make it easier to release the drug. In addition, in different atom doped fullerenes, the doped transition metal Ti fullerene is more suitable as 6MP carrier. This study provides a theoretical basis for the design of 6MP anticancer drugs in the future. [ABSTRACT FROM AUTHOR]

A new photonic approach for triangular waveform generation by making full use of the polarization sensitive characteristic of the single-drive Mach–Zehnder modulator (MZM) is proposed and experimentally demonstrated. In this method, the MZM is biased at minimum transmission point and its best modulation axis has an angle with the polarization direction of injection continuous wave (CW). Due to the polarization dependent modulation efficiency of a MZM, the odd-order modulation sidebands can be generated on the parallel polarization component but only the optical carrier is presented on the orthogonal direction. After a polarizer, the required Fourier components can be projected on the same polarization direction, which contribute a triangular pulse stream by photodetection. In the experimental demonstration, triangular waveforms with repetition frequencies of 8, 10, and 12 GHz are successfully generated, respectively. [ABSTRACT FROM AUTHOR]

Abstract: We used cDNA microarrays to identify differentially expressed genes in mice in response to infections with influenza virus A/PR/8/34 (H1N1) and Streptococcus pneumoniae. Expression microarray analysis showed up-regulation and down-regulation of many genes involved in the defense, inflammatory response and intracellular signaling pathways including chemokine, apoptosis, MAPK, Notch, Jak-STAT, T-cell receptor and complement and coagulation cascades. We have revealed signature patterns of gene expression in mice infected with two different classes of pathogens: influenza virus A and S. pneumoniae. Quantitative real-time RT-PCR results confirmed microarray results for most of the genes tested. These studies document clear differences in gene expression profiles between mice infected with influenza virus A and S. pneumoniae. Identification of genes that are differentially expressed after respiratory infections can provide insights into the mechanisms by which the host interacts with different pathogens, useful information about stage of diseases and selection of suitable targets for early diagnosis and treatments. The advantage of this novel approach is that the detection of pathogens is based on the differences in host gene expression profiles in response to different pathogens instead of detecting pathogens directly. [Copyright &y& Elsevier]