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Graphitic carbon nitride (g-C3N4) is considered a potential photoactive semiconductor for photocatalytic hydrogen evolution (PHE). Although being active in producing hydrogen, it is in general suffering from severe charge recombination rate, low mobility of charge and narrow visible light response range largely, which has restricted its greater application. Existing reviews on g-C3N4 are lacking of systematic and summative view on the effects of the physical-chemical structure-activity relationship between g-C3N4 and the modification involving phosphorus (P). Many studies indicate that adding P into g-C3N4 could effectively elevate the photo-activity. Underlying reasons for the observed improved photo-activity are discussed in this review. Here, P-containing g-C3N4 photocatalysts are grouped into the categories of P elemental doping, composite with elemental P, as well as the addition of metal phosphide as cocatalysts. These P-containing g-C3N4 possess novel properties demonstrating favorable photocatalytic activities as compared with the other elemental (such as O, S, B)-based materials. Therefore, in this mini review, we summarize and discuss the advances on the P-containing g-C3N4 photocatalysts, including the preparation strategies, physicochemical properties, the application for hydrogen production as well as the related reaction mechanism. Importantly, the physical-chemical structure-activity relationship between g-C3N4 and the integrated P is revealed. Finally, an overview of the current research status and challenges on future is presented, which would be helpful in designing and developing other P-containing photocatalysts for various photocatalytic applications.

Background Osteonecrosis of the femoral head (ONFH) is a common but intractable disease that appears to involve lipid metabolic disorders. Although numerous studies have demonstrated that high blood levels of low-density lipoprotein (LDL) are closely associated with ONFH, there is limited evidence to explain the pathological role of LDL. Pathological and in vitro studies were performed to investigate the role of disordered metabolism of LDL and oxidized LDL (ox-LDL) in the femoral head in the pathology of ONFH. Methods Nineteen femoral head specimens from patients with ONFH were obtained for immunohistochemistry analysis. Murine long-bone osteocyte Y4 cells were used to study the effects of LDL/ox-LDL on cell viability, apoptosis, and metabolism process of LDL/ox-LDL in osteocytes in normoxic and hypoxic environments. Results In the pathological specimens, marked accumulation of LDL/ox-LDL was observed in osteocytes/lacunae of necrotic regions compared with healthy regions. In vitro studies showed that ox-LDL, rather than LDL, reduced the viability and enhanced apoptosis of osteocytes. Pathological sections indicated that the accumulation of ox-LDL was significantly associated with impaired blood supply. Exposure to a hypoxic environment appeared to be a key factor leading to LDL/ox-LDL accumulation by enhancing internalisation and oxidation of LDL in osteocytes. Conclusions The accumulation of LDL/ox-LDL in the necrotic region may contribute to the pathology of ONFH. These findings could provide new insights into the prevention and treatment of ONFH.

The fully inorganic perovskite lead cesium bromide single crystal (CsPbBr3 SC) is considered as an excellent candidate semiconductor for photodetectors because of its superior humidity resistance, thermal stability, and light stability compared with organic-inorganic hybrid perovskites as well as its photoelectric properties such as large light absorption coefficient and ultralong carrier migration distance. In this Letter, we utilize the inverse temperature solubility of CsPbBr3 in ternary solvents to grow large-sized CsPbBr3 SCs. By the use of the (101) plane, CsPbBr3 SC-based photodetectors are fabricated, which exhibit excellent polarized light response characteristics. The photocurrent relies on the polarization angle in a sinusoidal fashion and shows strong anisotropic optoelectronic properties. The photodetection performance perpendicular to the y axis is significantly higher than that parallel to the y axis, and the dichroic ratio under 405 nm illumination at a bias voltage of 1 V reaches 2.65. The experimental results are consistent with the results of first-principles calculations.

Two-dimensional (2D) material-based heterojunction solar cells have attracted significant interest due to their potential in low-cost photovoltaic applications. Herein, a novel MXene/GaAs heterojunction solar cell with high efficiency and excellent stability has been achieved via a facile one-step method of drop casting for the first time. The high work function of the transparent MXene and the enhanced interfacial interaction between the MXene and GaAs contribute to the formation of a high-quality Schottky diode, resulting in a high initial power conversion efficiency (PCE) of 9.69%, surpassing those of other reported 2D material/semiconductor heterojunction solar cells. Moreover, after the deposition of a ZnS/MgF2 composite coating, the as-prepared MXene/GaAs heterojunction solar cell exhibits an average PCE of 12.5% with stability over 30 days in air. This work is of great importance for obtaining high-efficiency and air-stable solar cells for light-harvesting for sustainable development.

Summary Physical unclonable function (PUF) is a cornerstone of anticounterfeiting. However, conventional PUF key-based secure tags encounter several bottlenecks, such as complicated manufacturing, specialized and tedious readout, long authentication time, and insufficient stability. Here, we utilize various two-dimensional materials (2DMs), including Ti3C2Tx MXene and graphene oxide, to construct multigenerational microstructures as PUF patterns. Two intermediate treatments, cation intercalation and moisture-induced lubrication, are introduced in between sequential contractions to engineer the multiscale patterns in a transfer-free and scalable fashion. A deep learning (DL)-facilitated software is developed to pre-categorize the hierarchical topographies with classifiable features. Thereafter, the search-and-compare is conducted within a smaller database to shorten the overall authentication time. The synergy between 2DM tags and DL-facilitated software enables a reliable and environmentally stable anticounterfeiting technology, DeepKey, showing superior encoding capacity (>10144,494) and short authentication time (∼3.5 min). Our 2DM anticounterfeiting tag is finally integrated with QR codes to provide two-layer information security.

The dynamic effects, mainly including the inertia effect and strain-rate effect, on the dynamic wheel–rail contact behavior become more and more serious as the train speed increases. The inertia effect can be automatically taken into account in explicit finite element analysis codes, while the strain-rate effect needs to be considered via inputting the related material parameters. In the present paper, the influence of strain rate on the dynamic wheel–rail contact response for the straight track case was explored, based on a 3D wheel–rail rolling contact finite element model, via LS-DYNA/explicit algorithm. Effects of the axle load and train speed on typical dynamic wheel–rail responses were discussed, and the results indicate that the coupled train speed with strain rate has a non-negligible influence on dynamic contact responses. The strain rate hardening effect increases the maximum contact pressure and stress, and inhibits the plastic deformation of the wheel–rail system. A rate-sensitive factor (RSF) was then introduced to describe the strain rate hardening effect, confirming that the rail is more sensitive to strain rate compared to the wheel. Finally, an error analysis of the wheel–rail Hertz contact theory was conducted, which further verify the differences between elastic and elastic-plastic contact solutions.

CD146 was initially identified as a marker of melanoma in 1987. The research history of more than 30 years revealed its physiological functions in early development, immune response, metabolism, and pathological functions in inflammation, autoimmune diseases, tumor and pregnancy diseases. The understanding of the functional mechanisms of CD146 has also changed from mediating cell migration as an adhesion molecule to receiving extracellular signals and activating various intracellular signaling pathways as a cell membrane receptor. The correlation of CD146 to various diseases, especially its roles in tumors, inspired the application explorations of CD146 in diagnosis, prognosis and targeted therapy of those diseases, some of which has entered the clinical stage. In this review, to understand CD146 in an all-round way and develop its application potential in biomedicine, we comprehensively reviewed and summarized the research history of CD146 and addressed the prospect of the fundamental questions in its research and development.

Obstructive sleep apnea–hypopnea syndrome (OSAHS) is associated with alterations in glucose metabolism. The Berlin questionnaire (BQ) is effective in identifying subjects with high risk of OSAHS. However, its validity in patients with glucose metabolic dysfunction remains unclear. Our study aims to examine the diagnostic efficacy of the BQ in detecting OSAHS in patients with glucose metabolic dysfunction and to explore the effect of nasal CPAP on glucose metabolism. Patients with glucose metabolic dysregulation were first asked to complete the BQ and then recruited for polysomnogram (PSG). The diagnostic accuracy of the BQ and the relationships between groups with normal glucose tolerance (NGT), elevated fasting blood glucose (IFG), impaired glucose tolerance (IGT), and diabetes mellitus (DM) were analyzed. Subjects with both OSAHS and glucose dysregulation received CPAP treatment and underwent an oral glucose tolerance test. Changes in apnea-hypopnea indices (AHI) and glycemic parameters were calculated to determine the efficacy of CPAP. Glycosylated hemoglobin and insulin levels were statistically different between the high-risk and low-risk groups according to the BQ. For diagnosis of subjects with OSAHS who also had glucose metabolic dysfunction, the sensitivity and specificity of the BQ using AHI cut-off values at 5 events per hour were 73% and 67%. CPAP therapy effectively reduced the blood glucose, HOMA-IR, and insulin levels. The BQ can be considered to be an effective and economical screening tool for patieints with OSAHS who also have glucose metabolic dysfunction. Treatment with CPAP may improve glycemic parameters.

To evaluate the value of renal diffusion kurtosis imaging (DKI) in the diagnosis of early diabetic nephropathy (DN) in a rat model. Forty male Zucker diabetic fatty rats that spontaneously developed type 2 diabetes mellitus (DM) and 20 age-matched nondiabetic lean Zucker rats were included. Renal DKI scans and histological examinations were performed on the rats in batches at the end of the 4th, 8th, 12th, 16th, and 20th week after DM model was built. Based on renal histopathological appearance, included animals were divided into three groups: a nondiabetic control group, a DM group without DN, and an early DN group. Mean kurtosis (MK) and mean diffusivity (MD) values of renal cortex and medulla were analyzed statistically. MK values of renal cortex and medulla tended to increase from the control group to the early DN group, respectively, while MD values tended to decrease. The cutoff MD and MK values of renal cortex and medulla showed different values in discriminating early DN from controls. Among them, cutoff MK value of medulla of 0.62 was the best parameter (sensitivity, 93.9%; specificity, 96.4%; and area under the curve, 0.95). For discriminate early DN from DM without DN and DM without DN from controls, cutoff MK value of renal cortex or medulla achieved an area under the curve of 0.76–0.85. MR DKI may be valuable for the noninvasive detection of early DN, and MK value might serve as a more sensitive biomarker of early DN than MD value. • In this article, diffusion kurtosis imaging (DKI) was used to detect the changes in the kidneys due to early diabetic nephropathy (DN). • MR DKI may be valuable for the noninvasive detection of early DN. • The mean kurtosis values of renal cortex and medulla might serve as a more sensitive biomarker of early DN than the mean diffusivity values.

The wheel-rail rolling contact finite element model has been generally considered to be a better choice for solving the high-frequency wheel-rail responses and local stress/strain states, compared ...

Emerging soft exoskeletons pose urgent needs for high-performance strain sensors with tunable linear working windows to achieve a high-precision control loop. Still, the state-of-the-art strain sensors require further advances to simultaneously satisfy multiple sensing parameters, including high sensitivity, reliable linearity, and tunable strain ranges. Besides, a wireless sensing system is highly desired to enable facile monitoring of soft exoskeleton in real time, but is rarely investigated. Herein, wireless Ti3C2Tx MXene strain sensing systems were fabricated by developing hierarchical morphologies on piezoresistive layers and incorporating regulatory resistors into circuit designs as well as integrating the sensing circuit with near-field communication (NFC) technology. The wireless MXene sensor system can simultaneously achieve an ultrahigh sensitivity (gauge factor ≥ 14,000) and reliable linearity (R2 ≈ 0.99) within multiple user-designated high-strain working windows (130% to ≥900%). Additionally, the wireless sensing system can collectively monitor the multisegment exoskeleton actuations through a single database channel, largely reducing the data processing loading. We finally integrate the wireless, battery-free MXene e-skin with various soft exoskeletons to monitor the complex actuations that assist hand/leg rehabilitation.

Mismatched deformation in a bilayer composite with rigid coating on a soft substrate results in complex and uniform topographic patterns, yet it remains challenging to heterogeneously pattern the upper coatings with various localized structures. Herein, a heterogeneous, 3D microstructure composed of Ti3C2Tx titanium carbide (MXene) and single-walled carbon nanotubes (SWNTs) was fabricated using a one-step deformation of a thermally responsive substrate with designed open holes. The mechanically deformed SWNT-MXene (s-MXene) structure was next transferred onto an elastomeric substrate, and the resulting s-MXene/elastomer bilayer device exhibited three localized surface patterns, including isotropic crumples, periodic wrinkles, and large papillae-like microstructures. By adjusting the number and pattern, the s-MXene papillae arrays exhibited superhydrophobicity (>170°), strong and tunable adhesive force (52.3-110.6 μN), and ultra-large liquid capacity (up to 35 μL) for programmable microdroplet manipulation. The electrically conductive nature of s-MXene further enabled proper thermal management on microdroplets via Joule heating for miniaturized antibacterial tests. The s-MXene papillae were further fabricated in a piezoresistive pressure sensor with high sensitivity (11.47 kPa-1). The output current changes of s-MXene sensors were highly sensitive to voice vibrations and responded identically with prerecorded profiles, promising their application in accurate voice acquisition and recognition.

The blood-brain barrier (BBB) dysfunction is an initial event of various neuroinflammatory diseases. However, the absence of reliable markers and mechanisms for BBB damage greatly limits the diagnosis and treatment of neuroinflammatory diseases. Soluble CD146 (sCD146) is mainly derived from vascular endothelial cells (ECs) and highly elevated in inflammatory settings. Based on a small cohort, our previous study showed that sCD146 is elevated in the cerebrospinal fluid (CSF) of multiple sclerosis (MS), which is accompanied with BBB damage. Nevertheless, whether sCD146 monitors and regulates the BBB dysfunction remains unknown. Methods: Coupled serum and CSF samples from patients with or without neuroinflammatory diseases were collected via multicenter collaborations. sCD146 was measured by sandwich ELISA using anti-CD146 antibodies AA1 and AA98, both of which were generated in our laboratory. The correlations between sCD146 and other clinical parameters or inflammatory factors were analyzed by Spearman's correlation coefficient analysis. The role of sCD146 on BBB function was examined in an in vitro BBB model. Results: Between July 20, 2011, and February 31, 2017, we collected coupled serum and CSF samples from 823 patients, of which 562 (68.3%) had neuroinflammatory diseases, 44 (5.3%) had remitting MS, and 217 (26.4%) had non-inflammatory neurological diseases (NIND). We found that sCD146 in CSF, but not in serum, is abnormally elevated in neuroinflammatory diseases (37.3 ± 13.3 ng/mL) compared with NIND (4.7 ± 2.9 ng/mL) and remitting MS (4.6 ± 3.5 ng/mL). Abnormally elevated CSF sCD146 is significantly correlated with the hyperpermeability-related clinical parameters of BBB and neuroinflammation-related factors. Moreover, CSF sCD146 shows higher sensitivity and specificity for evaluating BBB damage. Using an in vitro BBB model, we found that sCD146 impairs BBB function by promoting BBB permeability via an association with integrin αvβ1. Blocking integrin αvβ1 significantly attenuates sCD146-induced hyperpermeability of the BBB. Conclusion: Our study provides convincing evidence that CSF sCD146 is a sensitive marker of BBB damage and neuroinflammation. Furthermore, sCD146 is actively involved in BBB dysfunction.

Background: Study failure in a course is very complicated which is always affected by many different factors and is characterized by uncertainties. We reviewed previous literatures and patents relating to student failure prediction, while there seems to be no ideal method or tool which can easily learn the relationship between failure results and reasons. Methods: In this study a method of artificial neural network was provided to predict student failure risk in course study. A three-layered network topology was used including input layer with nine neural nodes, hidden layer with ten optimized neural nodes, and output layer with one neural node, which is advantageous for dealing with this complicated and uncertain issue. The whole modeling process includes four stages: output inference, loss evaluation, weights and biases training, and model testing. Results: In our sample data there are 577 students in total, including 433 train cases and 144 test cases, and for each sample, there are nine input dependent variables and one output target variable. All calculation and optimization results were implemented based on the TensorFlow and Python. The model accuracy measurements of relative root mean square error on the total, test and train data sets were 0.1637, 0.1596, and 0.1607 respectively, and consistency was shown by testing the predicted results with our observed data, which indicated that the method was promising for predicting student failure risk in course study. Conclusion: It can be used to identify at-risk students with study difficulty and is of practical significance for educators to provide pedagogical supports and interventions in early time to the at-risk students to help them avoid academic failure, and it is also of theoretic significance to improve the whole efficiency of early warning education management.

In the paper, daily near-surface wind speed data from 462 stations are used to study the spatiotemporal characteristics of the annual and seasonal mean wind speed (MWS) and effective wind energy density (EWED) from 1960 to 2016, through the methods of kriging interpolation, least-squares, correlation coefficient testing, and empirical orthogonal function (EOF) analysis. The results show that the annual MWS is larger than 3 m s−1 and the EWED is larger than 75 W m−2 in northern China and parts of coastal areas. However, the MWS and EWED values in southern China are all smaller than in northern China. Over the past 50 years, the annual and seasonal MWS in China has shown a significant decreasing trend, with the largest rate of decline in spring for northern China and winter for coastal areas. The annual MWS in some areas of Guangdong has an increasing trend, but it shows little change in southwestern China, South China, and west of Central China. Where the MWS is high, the rate of decline is also high. The main spatial distributions of the annual MWS and the annual EWED show high consistency, with a decreasing trend year by year. The decreasing trend of wind speed and wind energy resources in China is mainly related to global warming and land use/cover change.

In this study, an explicit finite element analysis method was adopted to investigate the wheel–rail impact response generated by wheel polygonization, using a three-dimensional wheel–rail rolling contact finite element model. In this model, the infrastructure below the rails and the stiffness and damping of the sleeper supports were considered. Then, the characteristics of the wheel–rail contact zone, the stress/strain state and the wheel–rail impact force of the polygonal wheel–rail system were presented and discussed and were compared with those of the ideally perfect wheel–rail system. A parametrical study was then carried out to examine the influences of train speed and the polygonal order of the wheel on the wheel–rail impact response. The finite element analysis results revealed that the vertical wheel–rail impact force induced by wheel polygonization is related to the wheel radial deviation; the maximum contact force, stress and strain are all elevated with the increase of the order of the polygonal wheel, which suggested that the wheel should be repaired when it is in the initial lower order polygonal state. These findings can provide some theoretical and technical support for the optimal design of the wheel–rail system and the safe operation of high-speed trains.

Frontal sinus fractures are relatively rare maxillofacial injuries (only 5–15% of all facial fractures). The appropriate management of frontal sinus fracture and associated pathology is controversial. Diagnosis and treatment of frontal sinus fractures has improved with the advances of high-resolution computed tomography technology. Treatment of frontal sinus fractures depends on several factors, including contour deformity of anterior table; the presence of CSF leak or air–fluid level in the sinus, likelihood of nasofrontal duct obstruction, and degree of displacement of posterior table. Nasofrontal duct patency should be checked if fracture pattern is highly suspicious of ductal injury. Cranialization is performed in cases of severely comminuted posterior wall fracture. Long-term complication of frontal sinus fracture can occur up to 10 years after initial injury or intervention; so, judicious long-term follow-up is warranted. This article presents the management and complications of frontal sinus fractures.

The transient responses of car body and side windows for CRH2 high-speed trains passing by each other in a tunnel at different meeting conditions were investigated numerically using the Finite Element (FE) software LS-DYNA/explicit algorithm. Nine meeting cases including the case of meeting at the same speed and at the different speeds were respectively examined, where the moving pressure waves loaded on the surfaces of the observed train were obtained from the previous aerodynamics simulation. The typical transient responses (i.e., the stress and lateral displacement) of car body and side windows were analyzed, and the contribution of pressure wave to structural design strength of car body was also discussed. A comparison between the dynamic pressure wave loading simulation and the equivalent quasi-static loading simulation was also made. The simulation results indicate that both the von-Mises equivalent stress and lateral displacement of the car body are sensitive to the meeting speed. The side windows are subjected to the tensile stress in the most of response stage, and the maximum Y-directional stress of each monitor point presents a rapid increase with the increased meeting speed. The contribution rate of pressure wave to structural strength of the car body increases with the meeting speed. Besides, the dynamic pressure wave loading simulation method is demonstrated to be a better choice to investigate the transient response of the carriage. These research results are significant for ensuring the safety of the trains traveling in tunnels and elevating the safety of side windows.

As an extension of the conventional diffusion weighted imaging, diffusion kurtosis imaging (DKI) is based on the non-Gaussian diffusion model that can inherently account for restricted water diffusion within the complex microstructure of most tissues. This study aimed to investigate association of liver DKI derived parameter with stage of liver fibrosis.Fifty-six healthy New Zealand white rabbits were enrolled into this study, among which 48 rabbits were randomly given carbon tetrachloride to model liver fibrosis, and 8 rabbits treated with normal saline served as control subjects. All rabbits underwent liver DKI followed by biopsy to stage fibrosis (stages F0-F4) on 6th, 8th, 10th, and 12th weekends after initiation of modeling fibrosis. Mean kurtosis (MK), fractional anisotropy (FA), and mean diffusion (MD) were derived from DKI data. Statistical analysis was to evaluate association of DKI derived parameter with stage of fibrosis.FA (r = 0.512) and MK (r = 0.567) increased, and MD (r = -0.574) decreased with increasing stage of fibrosis from F0 to F4 (all p values0.05). Significant differences were found in all parameters between F0 and F3 or F4, F1 and F4, F0 and F1-4, and F0-1 and F2-4 (all p values0.05). FA and MD could distinguish between F0 from F2, MD, and MK could distinguish F1 from F3, F0-2 from F3-4, and F1-2 from F3-4, and MK and FA could distinguish F2 from F4, and F0-3 from F4 (all p values0.05). According to receiver operating characteristic analysis, MK could best predict stage ≥F1, ≥F2, ≥F3, and F4, and discriminate F1-2 from F3-4 with areas under receiver operating characteristic curve of 0.766-0.930.DKI derived parameters can help stage fibrosis.

Defocus blur is one of the primary problems among hyperspectral imaging systems equipped with simple lenses. Most of the previous deblurring methods focus on how to utilize structure information of a single channel, while ignoring the characteristics of hyperspectral images. In this work, we analyze the correlations and differences among spectral channels, and propose a deblurring framework for defocus hyperspectral images. First, we divide the hyperspectral image channels into two sets, and the set with less blur is treated as a group of spectral bases. Then, according to the inherent correlations of spectral channels, a reference image can be derived from the spectral bases to guide the restoration of blurry channels. Finally, considering the disagreement between the reference image and the ground truth, a scale map based on gradient similarity is introduced as a prior in the deblurring framework. The experimental results on public dataset demonstrate that the proposed method outperforms several image deblurring methods in both visual effect and quality metrics.

CH3NH3PbBr3 (MAPbBr3), one of the classical members in the organic–inorganic hybrid perovskite family that presents excellent advantages in high photon absorption efficiency and long carrier transp...

Due to the high density of surface states introduced in the nanorods growth process and subsequent exposure to air, electrons will be trapped in these states and recombine with photo-generated holes, which leads to a high loss of photo-generated carriers and creates a large onset potential for carrier transport. Here, we report a simple and low-cost surface treatment method, which utilizes H3PO4 to passivate surface states in the as-grown InGaN nanorods. Using optimized surface passivation condition, surface trapping states in as-grown InGaN nanorods can be removed by eliminating surface Indium aggregation, reducing the surface oxides, and saturating the dangling bonds. Hence, carrier recombination mediated by these surface states is weakened, as well as applied bias potential required for carrier transport is lowered. The optimized H3PO4-treated nanorods photoanode shows a larger photovoltage and a smaller charge transfer resistance to the electrolyte. Resultantly, a significant negative shift of onset potential from 0.7 to 0.3 V vs. RHE for the treated photoanode is achieved. Moreover, the optimized H3PO4-treated photoanode exhibits a high photocurrent density of 18 mA/cm2 at 1.23 V vs. RHE and a maximum applied bias photon-to-current efficiency value of 1.09%, whereas as-grown InGaN photoanode reaches only 0.64%.

Background Phthalates, which are used as excipients of drugs, have been related to adverse reproductive outcomes. However, the relationships between medication use and phthalate exposure among women undergoing in vitro fertilization (IVF) have not been studied. Objective To investigate the associations between the medication intake and phthalate metabolites in urine and follicular fluid (FF). Method Eight phthalate metabolites were measured in urine and FF samples from 274 women undergoing IVF using liquid chromatography-tandem mass spectrometry. Information on recent medication intake was obtained via interview by trained staff. We constructed generalized linear regression models to examine the associations of medication intake with phthalate metabolite concentrations and dose-response relationships between the number of medicines used and metabolite concentrations in two matrices. Results Four of 10 drugs were used by more than 10% of the participants, including vitamins (23.0%), traditional Chinese medicine (TCM, 22.3%), antioxidants (12.4%) and amoxicillin (10.2%). Participants who had used TCM had 26.0% (95% CI: 0.0, 58.8%), 32.6% (95% CI: 4.2, 68.8%) and 32.3% (95% CI: 2.6, 70.6%) higher urinary mono-n-butyl phthalate (MBP), mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) and mono(2-ethyl-5-oxohexyl) phthalate (MEOHP) concentrations, respectively, than those who had not. Antioxidant intake was associated with a 30.6% (95% CI: −48.5, −6.6%) decrease in the urinary MBP concentration. Compared with non-users, women who reported the use of medicines had 53.2% (95% CI: 2.7, 128.5%) higher concentrations of MMP and a 37.7% (95% CI: −60.7, −1.5%) lower level of MBP in FF, respectively. Conclusion Our data suggest that the intake of some medications may increase phthalate exposure among women undergoing IVF.

The Mars radiation environment, both in past and at present, plays a vital role in the evolution of Martian atmosphere, so it is necessary to detect the background radiation environment both in the Martian atmosphere and the transfer orbit from Earth to Mars. The Tianwen-1 Energetic Particle Analyzer (EPA) is designed to measure and analyze the energetic charged particles emitted to the Martian atmosphere. Mars-EPA consists of two parts: one is the Mars-EPA sensor head and the other is the Mars-EPA electronics system. This paper begins with an introduction of Mars-EPA structure and function of each part, followed by a simulation of how sensor head structure is designed. It then evaluates the performance of detection system using Geant4 software, to whether this sensor is capable of identifying the target particle and proposes a reasonable ground calibration procedure, which allows on overall detection performance to some degree. This Mars-EPA has demonstrated a potentially high capability and configurability which hopefully will shed light on future development of compact energetic detectors in deep space exploration.

Background The testes are suspected target organs of SARS‐CoV‐2. However, the results of studies on the effect of COVID‐19 on male reproduction are controversial. Objective To summarize current research on the effects of COVID‐19 on male reproduction. Methods A systematic review of English literature was performed using PubMed and Ovid Embase up to 18 August 2020. Research articles on the presence of SARS‐CoV‐2 in semen, the effects of the virus on semen parameters and any pathological changes in the testes were evaluated. Results Fourteen studies were included in this review. Six of 176 survivors (3.4%) and 1 of 13 decedents (7.7%) in 2 of 12 studies were positive for viral RNA in semen and testicular tissue, respectively. After stratification of patient groups, we found that the virus was detected in the relatively early stage of infection, 6–16 days after disease onset, in semen from survivors. Two of 3 studies reported that some participants had substandard semen quality after COVID‐19, and 1 study found that COVID‐19 may impair semen quality in a severity‐related manner. Pathological analyses showed that injuries to the seminiferous tubule occurred in all decedents (N = 11). Another study found that orchitic and testis fibrin microthrombi occurred in patients with fatal disease (100%, N = 2). Scrotal discomfort of orchiepididymitis or spermatic cord inflammation has also been reported in COVID‐19 patients. Conclusion Current studies suggest that semen is rarely considered a carrier of SARS‐CoV‐2 genetic material during the infection period but not in the semen of recovered patients. Fatal COVID‐19 may cause testicular structure damage without the presence of virus.

AIM AND SCOPE Our standard management is to operate isolated sagittal synostosis around 4 months of age because of morphological and cognitive outcomes. However, some patients present late and the likelihood of spontaneous remodeling is low in isolated sagittal craniosynostosis operated on after 12 months of age with a limited technique. The preliminary result of a modified technique for forehead remodeling and subtotal calvarial remodeling in nonsyndromic scaphocephalic children with late presentation is presented. PATIENTS AND METHODS All patients older than 1 with isolated sagittal synostosis assessed between 2011 and 2015, over 1 year of age at the time of surgery, with available pre and postoperative computed tomography-scans, were retrospectively included into the study. The following parameters were collected: (1) age at surgery, (2) duration of the procedure, (3) surgical technique, (4) fronto-nasal angle before and after surgery and (5) forehead width before and after surgery. RESULTS Ten patients aged between 15 months and 6 years were retrospectively included. Delayed surgery was due to late presentation or initial parental reluctance. All patients presented with a transversal narrowing of the forehead and an anterior bulge. Mean age at surgery was 28 months and mean follow up was 23 months (1-4 years). Measurements showed significant improvement of both the fronto-nasal angle and the width of the forehead. CONCLUSIONS Late-presenting scaphocephalic patients operated on after 12 months of age require forehead remodeling to achieve satisfactory aesthetic results. Modified forehead remodeling by splitting the forehead sagittally into 2 symmetrical halves and adding a midline bone strip is a safe and feasible way to widen the forehead. Long term follow-up is needed to assess this modified technique.

Human umbilical cord mesenchymal stem cell (UC-MSC) application is a promising arising therapy for the treatment of premature ovarian failure (POF). However, little is known about the inflammation regulatory effects of human umbilical cord MSCs (UC-MSCs) on chemotherapy-induced ovarian damage, regardless of in vivo or in vitro. This study was designed to investigate the therapeutic effects of UC-MSC transplantation and underlying mechanisms regarding both apoptosis and inflammation in POF mice. The chemotherapy-induced POF models were induced by intraperitoneal injection of cyclophosphamide. Ovarian function parameters, granulosa cell (GC) apoptosis, and inflammation were examined. Morphological staining showed that UC-MSC treatment increased the ovary size, and the numbers of primary and secondary follicles, but decreased the number of atretic follicles. Estradiol levels in the UC-MSC-treated group were increased while follicle-stimulating hormone levels were reduced compared to those in the POF group. UC-MSCs inhibited cyclophosphamide-induced GC apoptosis and inflammation. Meanwhile, phosphorylation of AKT and P38 was elevated after UC-MSC treatment. Tracking of UC-MSCs in vivo indicated that transplanted UC-MSCs were only located in the interstitium of ovaries rather than in follicles. Importantly, UC-MSC-derived extracellular vesicles protected GCs from alkylating agent-induced apoptosis and inflammation in vitro. Our results suggest that UC-MSC transplantation can reduce ovary injury and improve ovarian function in chemotherapy-induced POF mice through anti-apoptotic and anti-inflammatory effects via a paracrine mechanism.

spontaneous esophageal rupture (Boerhaave's syndrome) is a rare and challenging clinical condition.to evaluate the outcome of different surgical treatments for patients with Boerhaave's syndrome with an early diagnosis (24 h) and delayed diagnosis (24 h), using a retrospective cohort study in a tertiary referral center.eighty-eight patients with Boerhaave's syndrome who underwent surgical treatment were identified from March 1994 to March 2019 in the First Hospital of Shanxi Medical University. Subsequently, they were retrospectively divided into two groups according to time from symptom onset to diagnosis (group 1,24 h, n = 16; group 2,24 h, n = 72). Primary suture repair was used in group 1 and reinforcement with a vascular muscle flap was used in group 2, in order to reduce the incidence of fistula. Patients in group 2 were further divided into two subgroups according to reinforcement using diaphragmatic flaps (subgroup 1) or intercostal muscle flaps (subgroup 2).the duration of hospitalization and stay in Intensive Care Unit (ICU) was significantly shorter in group 1 (p = 0.027 and p = 0.001). Group 1 had fewer postoperative esophageal leaks (p = 0.037) compared to group 2. Various aspects were compared in the two subgroups and the differences were not statistically significant (p0.05).it is very important to establish an early diagnosis for patients with Boerhaave's syndrome. Early (24 h) and primary suture repair is superior to delayed (24 h) primary repair, even for those reinforced with vascular muscle flaps. Furthermore, repair reinforcement with different muscle flaps appears to render similar results for patients with delayed diagnosis.

As one type of organic–inorganic hybrid lead halide perovskites, MAPbX3 has attracted immense interests in applications of optoelectronic devices because of its remarkable properties. However, the ...

Due to their excellent luminescent properties such as high stability, narrow band emission, and strong luminescence, hybrid organic–inorganic lead perovskites have great potential for application in optoelectronic devices. Compared to their conventional 3D counterparts, 2D perovskites exhibit enhanced moisture stability. Moreover, with the enhancement of exciton binding energy and limitation of charge carriers, 2D layered perovskites are considered ideal candidate materials for efficient light-emitting diodes (LEDs). However, hybrid organic–inorganic lead perovskites contain highly toxic Pb, which is considered as a major environmental pollutant and health hazard. Therefore, the further larger-scale applications are limited. Thus, exploiting the impressive properties and practical applications of 2D layered structure Pb-free hybrid organic–inorganic perovskites in the LED field is necessary. In the present work, a centimeter-size square 2D layered Pb-free (CH3NH3)2MnCl4 single crystal was grown successfully with diverse crystal morphologies from two different solutions. This material could be excited by light in different wavelength bands. The main peak in its emission spectrum is located at 608 nm and the full width at half maximum (FWHM) is 72 nm. Furthermore, we prepared an LED using the (CH3NH3)2MnCl4 single crystal, which exhibited good luminescence properties, emitting obvious red light with a QE of 2.4% upon excitation at 417 nm and used for white light illumination.

Atomically thin nanomaterials represent a unique paradigm for interfacing with biological systems due to their mechanical flexibility, exceptional interfacial area, and ease of chemical functionalization. In particular, these two-dimensional (2D) materials are able to bend, curve, and fold in response to biologically-generated forces or other external stimuli. Such origami-like folding of 2D materials into wrinkled or crumpled topographies allows them to withstand large deformations by accordion-like unfolding, with implications for stretchable and shape-changing devices. Here, we review how mechanically manipulated 2D materials can interact with biological systems across a multitude of length scales. We focus on recent work where wrinkling, crumpling, or bending of 2D materials permits new chemical and material properties, with four case studies: (i) programming biomolecular reactivity and enhanced sensing, (ii) directed adhesion and encapsulation of bacteria or mammalian cells, (iii) stimuli-responsive actuators and soft robotics, and (iv) stretchable barrier technologies and wearable human-scale sensors. Finally, we consider future directions for manufacturing, materials and systems integration, as well as biocompatibility. Taken together, these 2D materials may enable new avenues for ultrasensitive molecular detection, biomaterial scaffolds, soft machines, and wearable technologies.

There has been great interest in the use of cesium lead bromide (CsPbBr3), which is one of the most important members of the all-inorganic perovskite family, due to its superior optoelectronic performance and higher stability. Recently, it has been demonstrated that it is advantageous to use CsPbBr3 microrods and nanowires in photodetectors because of their higher crystallinity, low amount of defects, and easy control of carrier transport along a specific direction as compared to their counterparts of single crystals and thin films. However, there is a shortage of adequate investigations that describe how to control the growth of CsPbBr3 microrods and nanowires so that they retain the optoelectronic performance of single CsPbBr3 microrods. Therefore, we are reporting how to control the growth of orientated dispersive super-long CsPbBr3 microrod single crystals (CsPbBr3 MSCs) via a simple anti-solvent method. The crucial factor in controlling the growth of dispersive super-long CsPbBr3 MSCs is the regulation of the rapid nucleation rate and slowing of the growth rate via controlling the diffusion velocity of anti-solvent methanol. We also reveal the growth mechanism of CsPbBr3 MSCs as layer-by-layer growth that originates from the 2D nucleus. The CsPbBr3 MSCs are revealed grew in the direction of [010], with the (101) facet exposed. Moreover, photodetectors based on one CsPbBr3 MSC were fabricated, and the detectivity (D) and the on/off ratio were as high as 3.67 × 1012 Jones and 988, respectively, suggesting a very strong optoelectronic response as photodetectors. The mechanism that the Cs ions and Cs vacancies use to move to negative and positive electrodes along the channels constructed by [PbBr6]4− in the [010] direction of the CsPbBr3 MSC (101) facet was revealed, after activation by the applied electrical field, which is beneficial to enhance the optoelectronic response but does not reduce the device stability.

To determine the therapeutic effect of Ziyin Jianghuo Ningxin Decoction (ZYJHNXD) plus dehydroepiandrosterone (DHEA) and menopausal hormone therapy (MHT) in patients suffering from menopausal symptoms identified as, in terms of Traditional Chinese Medicine, symptom pattern of Yin deficiency with hyperactive fire.Totally 180 postmenopausal women aged 40 to 60 years were assigned into four groups and accepted femoston, femoston with ZYJHNXD, femoston with DHEA, femoston with ZYJHNXD and DHEA therapies, respectively, for three months. Common questionnaire-based measure instruments included modified Kupperman index (MKI), Hamilton Rating Scale for Anxiety (HAMA), and Hamilton Rating Scale for Depression (HAMD). Follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E2), 5-hydroxyindole-3-acetic acid (5-HIAA), norepinephrine (NE), dopamine (DA), bone mineral density (BMD), and sleep quality were evaluated before and three months after the treatments.In all four groups, the scores of MKI, HAMA, HAMD and the levels of FSH, LH decreased significantly (P0.05) after the treatment, while the levels of E2, 5-HIAA, NE, and DA showed obvious elevation (P0.05). The group receiving ZYJHNXD and DHEA combined with femoston had superiority in the preservation of bone mineral density and improvement of total sleep time and nighttime sleep time over the other three groups.ZYJHNXD and DHEA combined with MHT therapy have a favorable outcome in managing menopausal symptoms, restoring hormone levels, preventing skeletal rarefaction or osteoporosis, and improving sleep quality for postmenopausal women.

Organic-inorganic hybrid methylammonium lead iodide perovskite (MAPbI3) has attracted extensive attention in a series of optoelectronic devices. The photoelectric properties of the MAPbI3 single crystal have been revealed to be much better than those of it polycrystalline counterparts. However, its poor moisture and heat resistance severely limited further development. The introduction of Cs+ into polycrystalline films has shown to be an effective way to enhance its moisture resistance through a passivation effect. However, the entrance abilities of Cs+ into a MAPbI3 crystal lattice and the influence on photoelectric properties of a single crystal were not clear until now. Therefore, we attempted to grow large MA1- xCs xPbI3 single crystals to introduce Cs+ into the crystal lattice. The existence of Cs+ brought lattice shrinkage and enhanced stability of the MAPbI3 single crystal. A moderate quantity of Cs+ (2%) proved to heighten the photoelectric properties, whereas an excess quantity of Cs+ (5%) brought more shallow defects, which ultimately deteriorated the photoelectric properties.

Objective: To determine whether T2∗ value of liver or that of spleen is better associated with the presence and Child–Pugh class of hepatitis B related cirrhosis. Materials and methods: Fifty-nine cirrhotic patients with hepatitis B and 21 healthy participants were enrolled in this study and underwent 3.0-T magnetic resonance imaging with T2∗-weighted sequence. Mean T2∗ values of liver and spleen were calculated. Statistical analysis was performed to compare the association of T2∗ value of liver and that of spleen with cirrhosis and its Child–Pugh class. Results: T2∗ values of liver and spleen might be indicators to discriminate cirrhotic patients from healthy individuals (all P

Peripheral nerve injuries can result in significant morbidity, including motor and/or sensory loss, which can affect significantly the life of the patient. Nowadays, the gold standard for the treatment of nerve section is end-to-end neurorrhaphy. Unfortunately, in some cases, there is segmental loss of the nerve trunk. Nerve mobilization allows primary repair of the sectioned nerve by end-to-end neurorrhaphy if the gap is less than 1 cm. When the nerve gap exceeds 1 cm, autologous nerve grafting is the gold standard of treatment. To overcome the limited availability and the donor site morbidity, other techniques have been used: vascularized nerve grafts, cellular and acellular allografts, nerve conduits, nerve transfers, and end-to-side neurorrhaphy. The purpose of this review is to present an overview of the literature on the applications of these techniques in peripheral nerve repair. Furthermore, preoperative evaluation, timing of repair, and future perspectives are also discussed.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Organic-inorganic hybrid methylammonium lead iodide perovskite (MAPbI3) is considered as new generation optoelectronic material. MAPbI3 single crystal is proved more excellent than its polycrystalline film and nano state counterparts, though the discrepancy is still pending. Referring MAPbI3 single crystal applications, physical anisotropy stands in its breach. However, it has not been drawn enough attentions till now. In this study, taking advantages of the natural exposed (100) and (112) facets of MAPbI3 single crystal grown from γ-butyrolactone (GBL) solution, the anisotropic optoelectronic performances based on of these two lattice planes were systematically explored through planar metal-semiconductor-metal (MSM) devices. An order enhanced photocurrents, 135% increased responsivity, and 128% heightened EQE on (112) plane device than those on (100) plane device under 5 V bias with irradiation power of 1 mW, remarkably demonstrated that (112) plane was more excellent in optoelectronic performances and light harvesting capability.

Hybrid perovskite MAPbCl3 is considered to be one of the most promising candidates applied in visible-blind UV-photo-detectors due to its outstanding optoelectronic properties. It is proved that the MAPbCl3 single crystal is more excellent than its polycrystalline counterpart because of its fewer defects and grain boundaries. When referring to a single crystal, the crystal orientation or crystal structure anisotropy is an inevitable topic, because structure anisotropy can affect or decide the optoelectronic properties of single crystals. In this study, both cubic and triangular prism MAPbCl3 single crystals with (100) and (110) crystallographic planes were successfully grown from mixed solutions. The crystal growth process, crystal structure and optical absorption were investigated. Moreover, by fabricating metal–semiconductor–metal (MSM) photo-detectors using Au interdigital electrodes on both (100) and (110) planes, the optoelectronic anisotropy was explored by comparing photocurrents, responsivity, external quantum efficiency and detectivity. According to the crystal structure and calculated charge density, the optoelectronic anisotropy in the MAPbCl3 single crystal was revealed.

Safety associated with ammonia requires the development of gas sensors for various applications, including food spoilage detection and livestock farming management. Radio-frequency identification (RFID) is a promising technology to fabricate a wireless gas sensor for remote concentration readouts. However, most of the reported RFID-enabled gas sensors determined the analyte concentration by using the reflection coefficient (S11) of sensor tag as an indicator, which was prone to be disturbed by measurement variations and external disturbances. Herein, we reported a wireless gas sensor with high tolerance to measurement variations through recognizing the resonant frequency (f) of sensor tag, enabling reliable detection of ammonia and various biogenic amines in real time. Compared with other conducting 2D materials, molybdenum disulfide (MoS2) exhibits tunable semiconducting properties and high specific surface area, which can serve a promising candidate for RFID-based gas sensors. By immobilizing silver nanoparticles-decorated molybdenum disulfide nanosheets (Ag@MoS2) on a nested split-ring resonator (SRR), the SRR sensor tag exhibited significant f downshifts at increasing ammonia concentrations, featuring with high sensitivity to ammonia (0.097 ppm–1, based on relative f changes), low detection limit ( 10,000 to provide reliable readouts of localized concentrations of biogenic amines.

Hybrid organic-inorganic lead halide perovskites (HOIPs) have received significant attention because of their impressive performances in the fields of solar cells and photoelectric detection. In the past five years, great efforts have been made to improve the crystallinity, reduce grain boundaries, and enhance the stabilities of perovskite films. Compared with films, HOIP single crystals possess fewer grain boundaries and stronger optoelectronic properties and can be applied in optoelectronic devices. As the most popular HOIP member, single crystals of MAPbX3 (X = Br, Cl) are deemed as important candidates for ultraviolet-visible photodetectors, in which the crystal structure anisotropy largely affects the detection performance. In this study, high-quality cubic single crystals of MAPbBr3 and MAPbCl3 were successfully grown from solutions. Taking advantages of their smooth (100) facets, planar metal-semiconductor-metal photodetectors were fabricated using Au interdigitated electrodes. The optoelectronic performances under nonpolarized and linearly polarized lights were explored. The optoelectronic performances were dependent on linearly polarized lights. Interestingly, both responsivity and external quantum efficiency were greatly enhanced under the excitation with linearly polarized lights. Moreover, the polarization-related optical absorptions and the electron densities within the (100) plane could be used to interpret different optoelectronic performances of single crystals of MAPbX3 (X = Br, Cl) under various linearly polarized lights.

MAPbI3 is deemed as the most prominent member in hybrid perovskites family because of its extremely optoelectronic properties. However, some issues and puzzles are still in expectation of their answers, such as stabilities, hysteresis, ferroelectricity, and so on. To bridge the distinctions between MAPbI3 single crystal and thin films, large-size single crystals are demanded. On the contrary, crystal structure anisotropy-dependent optoelectronic properties is an inevitable topic. A series of large-size MAPbI3 single crystals with (220) facets exposed were successfully grown, using high concentration solutions and large-size seed crystals to match growth rates of (100) and (220) facets. The optoelectronic properties of photocurrents, responsivity, EQE, and detectivity clearly showed significant anisotropy of optoelectronic properties in MAPbI3 single crystal. According to ion migration theory, the anisotropy of optoelectronic properties was interpreted. We hope this result will be helpful to guide oriented...

The optical properties of nanofluids need to be specified accurately to determine the effectiveness of nanofluids in photocatalytic reactions. In this study, the Monte Carlo method combined with the Mie scattering phase function was developed to calculate the optical properties and radiative transfer of TiO 2 nanofluids. The scattering effects caused by the directional scattering properties of the nanoparticles were considered during radiative transfer analysis of nanofluids. Size parameter ( χ ) was adopted as the criteria to divide the nanoparticles into two categories: small particle ( χ χ ≫ 1). The spectral transmissivity, absorption coefficient, extinction coefficient, and scattering characteristics of TiO 2 nanofluids were theoretically analyzed. The numerical results indicate that the optical properties of nanofluids with small particles vary smoothly with wavelength, while the optical properties of nanofluids with large particles oscillate with wavelength due to diffraction peaks. This study concluded that the scattering effects need to be considered during investigation of optical properties and radiative transfer of nanofluids.

A series of Pb(Zr1-xTix)O3 multilayer films alternatively stacked by Pb(Zr0.52Ti0.48)O3 and Pb(Zr0.35Ti0.65)O3 layers have been deposited on corning glass by magnetron sputtering. The films demonstrate pure perovskite structure and good crystallinity. A large tetragonality (c/a) of ∼1.061 and a shift of ∼0.08 eV for optical bandgap were investigated at layer engineered films. In addition, these samples exhibited a wild tunable electro-optic behavior from tens to ∼250.2 pm/V, as well as fast switching time of down to a few microseconds. The giant EO coefficient was attribute the strain-polarization coupling effect and also comparable to that of epitaxial (001) single crystal PZT thin films. The combination of high transparency, large EO effect, fast switching time, and huge phase transition temperature in PZT-based thin films show the potential on electro-optics from laser to information telecommunication. ASTAR (Agency for Sci., Tech. and Research, S’pore) MOE (Min. of Education, S’pore) Accepted version

An experimental investigation into the dynamic compressive response of high-strength concrete with three different strengths – 60 MPa, 80 MPa and 110 MPa, denoted by C60, C80 and C110, respectively – was undertaken. Concrete specimens were subjected to quasi-static and dynamic compression, using a Denison Universal Testing Machine and a Split Hopkinson Pressure Bar (SHPB) device, and the effects of strain rate on their mechanical properties (e.g. stress-strain relationship, compressive strength) examined. Significant rate dependence was observed for all three concretes – i.e. the compressive strength increases with strain rate and the dynamic strength is much higher than the static value; C60 and C80 exhibited similar rate sensitivity, while C110 displayed a relatively noticeably lower rate dependence. The rate sensitivity was quantified via a Dynamic Increase Factor (DIF, the ratio between the dynamic and static strength), and this was compared with predictions by the CEB-FIP 2010 equation, commonly utilised to estimate rate sensitivity for normal strength concrete. The comparison indicates that the model is not suitable for high-strength concrete, as it predicts a sharper rise in rate-sensitivity, and the mismatch increases with concrete strength, becoming notably significant for C110. Interpretation of rate dependence of concrete materials based on SHPB test results, as to whether it is an intrinsic material property, or generated primarily by radial inertia, was examined by finite element modelling of SHPB tests. Concrete material properties were taken to correspond to a concrete damaged plasticity model, and the quasi-static stress-strain response, coupled with the Dynamic Increase Factor determined from dynamic tests, was utilised. The simulation results correlated closely with experiments, in terms of strain gauge signal histories in the SHPB loading bars, indicating that for the strain rate range investigated (30–110 s −1 ), radial inertia is not significant, and the rate dependence observed is attributable to material response.

The perforation resistance capability of clamped square sandwich panels with layered gradient metallic foam cores subjected to the hemispherical-nosed projectile impact was investigated numerically. The previous penetration tests on monolithic foam core sandwich panels were used to validate the present simulation approach, and then the deformation process, critical velocity and energy absorption of monolithic Al plate, ungraded and layered-gradient sandwich targets were studied, respectively. Influences of the strain rate and asymmetric face-sheets on the perforation resistance of the layered-gradient sandwich target were also discussed. The simulation results indicate that layered-gradient sandwich targets have the worst perforation resistance and energy absorption capability, and then the ungraded sandwich panel, and the monolithic plate is the best. For layered-gradient sandwich panels, the perforation resistance is hard to improve obviously by changing the arrangements of core-layers. Besides, the strain rate effect of materials and asymmetric face-sheets contribute to enhance the perforation resistance of layered-gradient sandwich targets only for the low-velocity penetration condition. These findings are beneficial for guiding the design and assessment of layered-gradient sandwich structures in engineering applications.

A comprehensive dynamic finite-element simulation method was proposed to study the wheel–rail impact response induced by a single wheel flat based on a 3-D rolling contact model, where the influenc...

A three-dimensional (3-D) wheel-rail rolling contact model with a wheel flat was built using commercial software Hypermesh, and the dynamic finite element simulation was conducted using LS-DYNA 3D/explicit code. Influences of the train speed, flat length and axle load on the vertical wheel-rail impact response were discussed, respectively. The results show that the maximum vertical wheel-rail impact force induced by the wheel flat is higher than that generated by the perfect wheel, and these two dynamic impact forces are much greater than the static axle load. Besides, the maximum von Mises equivalent stress and maximum equivalent plastic strain are observed on the wheel-rail contact surface, and both of them as well as the maximum wheel-rail impact force are sensitive to train speed, flat length and axle load.