Electrostatic doping tunable magnetic transition and half-metallicity in the monolayer CrCTe3.

The electrical manipulation of the magnetic transition and spin-polarized states has attracted extensive attention in the field of spintronics. In this work, we perform a detailed study on the electronic and magnetic properties of the carrier-doped monolayer CrCTe3by using first-principles calculation. It is found that, the magnetic transition from Néel-antiferomagnetic (nAFM) to ferromagnetic (FM) is observed in the case of the electron doping, while for hole doping a magnetic transition sequence of nAFM→zigzag-AFM→FM is observed in the monolayer CrCTe3. Interestingly, the carrier doping induced FM ground state always exhibits half-metallicity with full spin polarization. Moreover, the spin polarity of the half-metallic electronic states is opposite for electron and hole doping, meaning that the spin polarization direction can be tuned by manipulating a gate voltage. The Monte Carlo calculations show that the magnetic transition temperature of the doped FM CrCTe3is rapidly increased with the increasing doping concentration and is extremely expected to achieve room temperature at a suitable doping concentration. These findings demonstrate that the monolayer AFM system possesses a potential application in spintronic devices with electrically tunable spin polarization.

Novel Topological Motifs and Superconductivity in Li-Cs System.

In this work, we determined the phase diagram and electronic properties of the Li-Cs system by using an evolutionary crystal structure prediction algorithm coupled with first-principles calculations. We found that Li-rich compounds are more easily formed in a wide range of pressures, while the only predicted Cs-rich compound LiCs3 is thermodynamically stable at pressures above 359 GPa. A topological analysis of crystal structures concludes that both Li6Cs and Li14Cs have a unique topology that has not been reported in existing intermetallics. Of particular interest is the fact that four Li-rich compounds (Li14Cs, Li8Cs, Li7Cs, and Li6Cs) are found to be superconductors with a high critical temperature (∼54 K for Li8Cs at 380 GPa), due to their peculiar structural topologies and notable charge transfer from Li to Cs atoms. Our results not only extend an in-depth understanding of the high-pressure behavior of intermetallic compounds but also provide a new route to design new superconductors.

Theoretical investigation of the role of hydrogenation-induced strain in single-layer h10-Si.

Although great efforts have been dedicated to exploring hydrogenated two-dimensional (2D) materials, there are few reports about the role of hydrogenation-induced equivalent strain effects in tuning the physical properties. Here, based on density functional theory, we systematically reveal the non-negligible role of the hydrogenation-induced strain and its effects on the electronic and optical properties in single-layer (SL) h10-Si. We demonstrate that hydrogenation can trigger an electronic transition from an indirect- to a direct-band-gap semiconductor mainly due to the energy level rearrangement of the partial p orbitals caused by the equivalent strain. The electronic transition in SL h10-Si occurs at a critical hydrogenation concentration of about 87.5%. Furthermore, it is found that hydrogenation can continuously shift the light absorption peak of SL h10-Si in the photon-energy range of 1.64-2.44 eV by changing the pz-pz dipole transition. Our findings provide an example of tuning the electronic properties of 2D materials via hydrogenation-induced strain, which is important for understanding the physical mechanism of the hydrogenation-tuned physical properties of such materials.

[Role of pyroptosis in bilirubin-induced microglial injury].

OBJECTIVE: To study whether pyroptosis is involved in the bilirubin-induced injury of primary cultured rat cortical microglial cells. METHODS: Primary cultured rat cortical microglial cells were randomly administered with 30 µmol/L bilirubin (bilirubin group), 30 µmol/L bilirubin following 30 µmol/L VX-765 pretreatment (VX-765+bilirubin group), or an equal volume of dimethyl sulfoxide (control group). Modified MTT assay was used to measure the viability of microglial cells. Western blot was used to measure the expression of the pyroptosis-related proteins Caspase-1 and gasdermin D (GSDMD). Lactate dehydrogenase (LDH)-release assay was used to evaluate the cytotoxicity of microglial cells. EtBr/EthD2 with different molecular weights (394 Da/1 293 Da) was used to measure the size of plasma membrane pores. ELISA was used to measure the level of the inflammatory factor interleukin-1ß (IL-1ß) in culture supernatant. RESULTS: After bilirubin stimulation, the viability of microglial cells decreased and LDH release increased, both in a time-dependent manner. Compared with the control group, the bilirubin group had a significantly higher positive rate of small-molecule EtBr passing through the cell membrane (P<0.001), while there was no significant difference in the pass rate of large-molecule EthD2 between groups (P>0.05). The expression of activated Caspase-1 significantly increased at 0.5 hour after bilirubin stimulation (P<0.05), and that of activated GSDMD significantly increased at 6 hours after bilirubin stimulation (P<0.05). The release of IL-1ß significantly increased at 6 hours after bilirubin stimulation and reached the peak at 24 hours (P<0.001). Compared with the bilirubin group, the VX-765+bilirubin group had a significant increase in cell viability (P<0.05) and significant reductions in the expression of activated GSDMD, the pass rate of EtBr, and the release of LDH and IL-1ß (P<0.05). CONCLUSIONS: Pyroptosis is involved in bilirubin-induced injury of primary cultured microglial cells.

Pressure-Induced Structural Phase Transition and Superconductivity in NaSn5.

The structural and electronic properties of the tin-rich compound NaSn5 were investigated under pressures of up to 10 GPa on the basis of the evolutionary algorithm (EA) technique coupled with first-principles total energy calculations. Upon compression, the known metallic tetragonal P4̅21m phase transforms into a metallic hexagonal P6/mmm phase at 1.85 GPa accompanied by an unusual change in the existing form of Sn atoms. The P6/mmm phase can be interpreted as a quasi-layered sandwich structure with two Sn layers and one sodium layer. The presence of softening phonon modes and the existence of Fermi pockets together with the obvious Fermi surface nesting indicate a strong electron-phonon coupling (EPC) and thus potential superconductivity in the P6/mmm phase. The strong EPC in the P6/mmm phase is mainly attributed to the phonons from Sn1 atoms together with electrons from the Sn1 py and Sn1 pz states. The calculated superconducting critical temperature Tc of the P6/mmm phase is 5.91 K at 1.85 GPa. This study provides a new clue for designing intercalated compounds with superconductivity.

[Occurrence of Tramadol and Fentanyl Use in Domestic Wastewater in Beijing].

Tramadol (TRA) and fentanyl (FEN) are used as common painkillers in clinical practice, but they have been increasingly abused in recent years due to their addictive nature. Two substances and their metabolites enter wastewater through urine and are collected and treated by wastewater treatment plants (WWTPs) before being discharged into the aquatic environment. In this study, wastewater analysis was performed to examine the patterns of TRA and FEN use in the urban area of Beijing for the first time. Influent and effluent samples were collected from 23 WWTPs during two sampling campaigns. Concentrations TRA in influents were found to range from(10.2±8.7)to(175.3±59.7) ng·L-1, while FEN was not detected in most of the samples, or occurred at very low concentrations. Relatively low TRA removal was observed at plants with activated sludge processes. Moreover, TRA loads in the central area of Beijing were significantly higher than those in the suburban areas. Annual TRA use was estimated through wastewater-based epidemiology. The greatest TRA use, approximately 202.5 kg, was found in Haidian district. Seasonal variation in TRA loads was significant, with greater use in the summer than in winter. The method presented in this study can be used as an important reference for monitoring TRA and FEN use via wastewater-based epidemiology and for assessing the risk of the abuse of these compounds in China.

Human cytomegalovirus glycoprotein B inhibits migration of breast cancer MDA-MB-231 cells and impairs TGF-ß/Smad2/3 expression.

Breast cancer is a leading cause of cancer-associated mortality in females worldwide and evidence suggests that human cytomegalovirus (HCMV) infection may be implicated in the progress of breast cancer. HCMV glycoprotein B (gB) is the most abundant envelope protein and serves an important role in host cell entry. The present study aimed to clarify the role of HCMV gB in breast cancer cells. A HCMV gB construct (UL55) was generated and stable vUL55 gene lentivirus-transfected MDA-MB-231 cells were established. Subsequently, the effect of HCMV gB on the apoptosis and proliferation of MDA-MB-231 cells was measured by flow cytometry and Cell Counting Kit-8 assay. Furthermore, whether HCMV gB may modulate MDA-MB-231 cell migration was examined using Transwell and cell scratch assays. In addition, alterations in HCMV gB-modulated protein levels of transforming growth factor-ß (TGF-ß) and Mothers against decapentaplegic homologs 2/3 (Smad2/3) were detected using western blot analysis. The results indicated that UL55 cDNA was stably transfected into MDA-MB-231 cells, and that HCMV gB protein was stably expressed. No significant differences in cell apoptosis and proliferation between transfected (231-GB-OE) and negative control (231-NC) cells were observed, while the rate of cell migration was significantly decreased in the 231-GB-OE cells compared with the 231-NC cells. Additionally, the expression level of TGF-ß and phosphorylation level of Smad2/3 were also decreased in 231-GB-OE cells compared with the 231-NC cells. Although certain previous studies indicated that HCMV infection was associated with breast carcinogenesis, the results of the present study indicate that the envelope protein HCMV gB exhibits no effect on cell apoptosis and proliferation, but inhibits breast cancer cell migration. This may be due to downregulated TGF-ß/Smad signaling. Taken together, these studies may assist in developing anti-TGF-ß agents that contribute to tumor suppression.

Structural diversity and electronic properties in potassium silicides.

Stable potassium silicides in the complete compositional landscape were systematically explored up to 30 GPa using the variable-composition evolutionary structure prediction method. The results show that K4Si, K3Si, K5Si2, K2Si, K3Si2, KSi, KSi2, KSi3, and K8Si46 have their stability fields in the phase diagram. The spatial dimensional diversity of polymerized silicon atoms (0D "isolated" anion, dimer, Si4 group, 1D zigzag chain, 2D layer, and 3D network) under the potassium sublattice was uncovered as silicon content increases. Especially, the 2D layered silicon presents interestingly a variety of shapes, such as the "4 + 6" ring, "4 + 8"ring, and 8-membered ring. K-Si bonding exhibits a mixed covalency and ionicity, while Si-Si bonding is always of covalent character. Semiconductivity or metallicity mainly depends on the form of sublattices and K:Si ratio, which allows us to find more semiconductors in the Si-rich side when closed-shell K cations are encompassed by polymerized Si. The semiconducting silicides present strong absorption in the infrared and visible light range. These findings open up the avenue for experimental synthesis of alkali metal-IVA compounds and potential applications as battery electrode materials or photoelectric materials.

[Monitoring of Crack Propagation in Repaired Structures Based on Characteristics of FBG Sensors Reflecting Spectra].

In order to improve the security of aircraft repaired structures, a method of crack propagation monitoring in repaired structures is put forward basing on characteristics of Fiber Bragg Grating (FBG) reflecting spectra in this article. With the cyclic loading effecting on repaired structure, cracks propagate, while non-uniform strain field appears nearby the tip of crack which leads to the FBG sensors' reflecting spectra deformations. The crack propagating can be monitored by extracting the characteristics of FBG sensors' reflecting spectral deformations. A finite element model (FEM) of the specimen is established. Meanwhile, the distributions of strains which are under the action of cracks of different angles and lengths are obtained. The characteristics, such as main peak wavelength shift, area of reflecting spectra, second and third peak value and so on, are extracted from the FBGs' reflecting spectral which are calculated by transfer matrix algorithm. An artificial neural network is built to act as the model between the characteristics of the reflecting spectral and the propagation of crack. As a result, the crack propagation of repaired structures is monitored accurately and the error of crack length is less than 0.5 mm, the error of crack angle is less than 5 degree. The accurately monitoring problem of crack propagation of repaired structures is solved by taking use of this method. It has important significance in aircrafts safety improvement and maintenance cost reducing.

[Bisphenol A alters glucose metabolism in rat Sertoli cells in vitro].

OBJECTIVE: To observe the influence of different concentrations of bisphenol A (BPA) on glucose metabolism and lactate dehydrogenase (LDH) expression in rat Sertoli cells in vitro and investigate the mechanisms of BPA inducing male infertility. METHODS: Using two-step enzyme digestion, we isolated Sertoli cells from male Wistar rats and constructed a primary Sertoli cell system, followed by immunohistochemical FasL staining. We randomly divided the Sertoli cells into a control group to be cultured in the serum-free minimal essential medium (MEM) plus dimethyl sulfoxide (DMSO) and three experimental groups to be treated with 100 nmol/L, 10 µmol/L, and 1 mmol/L BPA, respectively, in the MEM plus DMSO. After 48 hours of treatment, we measured the proliferation of the cells by CCK-8 assay, determined the concentrations of metabolites by NMR spectroscopy, and detected the expression of LDH in the Sertoli cells by RT-PCR and Western blot. RESULTS: The purity of the isolated Sertoli cells was (96.05 ± 1.28)% (n = 10). Compared with the control group, the 100 nmol/L, 10 µmol/L, and 1 mmol/L BPA groups showed no remarkable changes in the proliferation of Sertoli cells ([98 ± 8]%, [96 ± 3]%, and [95 ± 3]%, P >0.05), but the 10 µmol/L and 1 mmol/L of BPA groups exhibited significantly decreased concentrations of intracellular glucose ([3.89 ± 0.07] vs [3.36 ± 0.24] and [3.04 ± 0.21] pmol/cell, P <0.05) and lactate ([0.43 ± 0.06] vs [0.29 ± 0.05] and [0.20 ± 0.03] pmol/cell, P <0.05). The expression of LDH mRNA was decreased with the increased concentration of BPA, while that of LDH protein reduced only in the 1 mmol/L BPA group (P <0.05). CONCLUSION: High-concentration BPA decreases the expression of LDH and alters glucose metabolism in Sertoli cells, and therefore may reduce the provision of lactate for germ cells and impair spermatogenesis.

[Contrast-enhanced ultrasonography for detecting testicular perfusion in acute testis contusion in rabbits].

OBJECTIVE: To evaluate contrast-enhanced ultrasonography (CEUS) in detecting testicular perfusion in acute testis contusion. METHODS: We established the model of testis contusion in 11 healthy male New Zealand rabbits by randomly hitting one side of the scrotum under general anesthesia. We examined the bilateral scrotums of all the animals before, immediately after and at 2, 4 and 6 hours after modeling by color Doppler flow imaging (CDFI) and CEUS, and analyzed the time-intensity curve (TIC), arriving time (AT), time to peak intensity (TTP), peak intensity (PI), half time of descending peak intensity (HT) and area under the curve (AUC) in the healthy and injured testis, respectively. RESULTS: CEUS exhibited a higher sensitivity in detecting tissue perfusion than CDFI. The mode of contrast agent perfusion in testicular contusion was fast in and slow out. There were no evident differences between the contused and the healthy testis in AT, TTP and PI before modeling. The contused testis showed significantly earlier AT and TTP, higher PI and larger AUC (P < 0.05) than the healthy one at different time points after modeling, but no statistically significant difference was found in HT (P > 0.05). CONCLUSION: Accurate parameters of testicular perfusion in acute testis contusion can be quantitatively obtained by CEUS, which are of important value for the diagnosis of testis contusion.

Marginal vitamin A deficiency affects lung maturation in rats from prenatal to adult stage.

UNLABELLED: Mild or marginal vitamin A deficiency (MVAD) is still a serious and widespread public health problem in pregnant women and children in developing countries. This study investigated rat lung maturation from prenatal to adult stage during pregnancy and postnatal MVAD and the recovery after postnatal vitamin A supplementation (VAS). Adult female rats and their offspring were randomized into three groups. 1. CONTROL: the mothers and offspring received a normal diet.2. MVAD: The mothers and offspring received a MVAD diet.3. VAS: the mothers received MVAD diet till parturition, and then received the normal diet. The offspring of the VAS group were given low-dose vitamin A from postnatal day 1 to day 7 and received the normal diet after weaning. The lung development, structure, and collagen and elastic fiber of offspring were monitored by morphometric analysis at age 1 d, 2 and 8 wk, respectively. Lower body weight, lung weight, reduced numbers of alveoli and total alveolar surface area as well as increased alveoli septa thickness was observed in MVAD compared to that in the control animals. Increased collagen deposits and decreasing elastic fiber were found in MVAD rats. However, all of these were significantly improved in VAS-treated animals. These data suggest that the rat lung is sensitive to MVAD during the developing stage. Early postnatal vitamin A supplementation can partially restore the normal lung structure.

[Propofol protecting rats from paraquat induced lung injury].

OBJECTIVE: To investigate the protective efficacy of propofol against paraquat induced lung injury. METHODS: One hundred and twenty-eight male Wistar rats were randomizedly divided into three groups: the control group (n = 8), the intoxication group (n = 60) and the propofol group (n = 60). One hundred and twenty rats were once administered with 5 mg/kg paraquat (PQ) by the intragastrical injection to establish the model of PQ induced lung injury. The propofol of 10 mg/kg was administered intraperitoneally in the propofol group (60 rats) twice a day for four consecutive days one hour after the rats were intoxicated while the normal saline of the same amount as propofol in the propofol group was administered in the intoxication group (60 rats) one hour after the rats were intoxicated. The intragastrical injection of 1 mg/kg normal saline was administered once in the control group (8 rats). On the first, the third, the seventh, the 14th and the 28th day after treating, the level of malondialdehyde (MDA) in plasma, bronchoalveolar lavage fluid (BALF) and lung homogenate, and the content of hydroxyproline (HPY) in lung homogenate, the cell count of BALF were detected. Meanwhile, pathological changes of lung were examined under optical microscope. RESULTS: The level of MDA in plasma on the first, the third and the seventh day and in BALF and lung homogenate on the first and the third day in the propofol group [in plasma: (4.31 +/- 0.94), (4.04 +/- 0.87) and (3.24 +/- 1.14) nmol/ml; in BALF: (3.47 +/- 1.09) and (2.79 +/- 1.11) nmol/ml; in lung homogenate: (7.54 +/- 0.63) and (8.41 +/- 1.23) nmol/ml] were significantly lower than those in the intoxication group [in plasma: (10.15 +/- 3.15), (6.97 +/- 1.6 5) and (5.44 +/- 0.66) nmol/ml; in BALF: (5.58 +/- 1.19) and (4.86 +/- 1.89) nmol/ml; in lung homogenate: (10.20 +/- 2.43) and (10.71 +/- 171) nmol/ml, P < 0.05 or P < 0.01]. The total cell count of BALF on the first, the third and the seventh day after intoxication in the propofol group was significantly less than that in the intoxication group respectively (P < 0.05). The histological changes such as alveolar edema, hemorrhage and inflammatory cell infiltration in the propofol group were less than those in the PQ group. CONCLUSION: Propofol could reduce the level of MDA and relieve paraquat induced lung injury.

A sensitive optode membrane for berberine using conjugated polymer as sensing material.

A new optode membrane for the sensitive determination of berberine based on fluorescence quenching of a conjugated polymer, poly(2,5-dimethoxy-phenyldiacetylene) (PDPA), is proposed. Incorporated in a membrane composed of plasticized poly(vinyl chloride) (PVC), the conjugated polymer exhibits better stability than those small sensing molecules regarding its excellent optical properties and lipophilic characteristics. Moreover, upon the introduction of a negatively charged lipophilic additive (tetraphenylborate salt) into a PVC membrane, the optode displayed enhanced sensitivity. In addition, satisfactory analytical sensing characteristics for determining beberine were obtained in terms of the selectivity, reversibility and reproducibility with a detecting range of between 7.5 x 10(-7) mol l(-1) and 7.5 x 10(-4) mol l(-1). The optode membrane has been applied to determine berberine in commercial tablets. The results showed a good agreement with those obtained by the pharmacopoeial method.