Heats of formation and stress-strain relationship of Fe-Cr solid solutions from a constructed Fe-Cr potential.

A new Fe-Cr interatomic potential is constructed under the framework of the embedded-atom method and has better performances in predicting heats of formation and stress-strain relationship of Fe-Cr solid solutions than the Fe-Cr potentials already published in the literature. Based on the constructed Fe-Cr potential, molecular dynamics simulation reveals that the heats of formation of BCC Fe-Cr solid solutions at 1600 K are positive within the entire composition range, and the calculated values are in good agreement with corresponding experimental measurements in the literature. In addition, it is also found that the tensile strengths of BCC Fe-Cr solid solutions increase with the increase of the Cr composition, and that BCC Fe-Cr solid solutions are less ductile with smaller critical strains than both Fe and Cr. The simulated results are discussed and compared with the corresponding experimental and calculated evidence in the literature to validate the relevance of the newly constructed Fe-Cr potential.

Atomistic modelling of the immiscible Fe-Bi system from a constructed bond order potential.

An analytical bond-order potential (BOP) of Fe-Bi has been constructed and has been validated to have a better performance than the Fe-Bi potentials already published in the literature. Molecular dynamics simulations based on this BOP has been then conducted to investigate the ground-state properties of Bi, structural stability of the Fe-Bi binary system, and the effect of Bi on mechanical properties of BCC Fe. It is found that the present BOP could accurately predict the ground-state A7 structure of Bi and its structural parameters, and that a uniform amorphous structure of Fe100-xBixcould be formed when Bi is located in the composition range of 26 ⩽x< 70. In addition, simulations also reveal that the addition of a very small percentage of Bi would cause a considerable decrease of tensile strength and critical strain of BCC Fe upon uniaxial tensile loading. The obtained results are in nice agreement with similar experimental observations in the literature.

Whole-genome resequencing reveals genetic structure and introgression in Pudong White pigs.

Pudong White (PDW) pigs, historically originating from Shanghai, are the only Chinese indigenous pigs characterised by their completely white coats, with the exception of Rongchang pigs. However, there is limited information concerning their overall genetic structure or relationship with other breeds, especially the East Chinese (ECN) and European pigs. To uncover the genetic structure, selection signatures, and potential exotic introgression in PDW pigs, we sampled 15 PDW pigs using whole-genome sequencing (~20×). We then conducted in-depth population genetic analyses in 320 pigs from 27 global pig groups, namely, European wild boars, Chinese wild boars, and outgroup. Neighbour-joining tree and principal component analysis confirmed that PDW pigs belonged to the ecotype of ECN pigs. Both f3, D-statistics, and structure analysis showed that PDW pigs shared apparent alleles with Large White (LW) pigs. Three statistics, rIBD, a haplotype heat map and copy number variation, further indicated that PDW pigs shared apparent alleles with LW pigs at the KIT Proto-Oncogene, Receptor Tyrosine Kinase (KIT) and PARG-MARCHF8 loci, suggesting that the lineage of European pigs in PDW originated from LW pigs. After further detecting the KIT mutations in different pig breeds, PDW was confirmed to have the same duplication region 1, duplication region 2, and the splicing mutation on intron 17 of KIT as LW pigs that determine the white coat colour phenotype in European white pigs. We hypothesised that LW pigs were imported to China ∼110-160 years ago according to the admixture time estimate and then crossed with ECN pigs, resulting in the introgression of the KIT alleles that produce the white coat colour phenotype in the PDW pig breed. To our knowledge, this study presents the first thorough description of the genetic structure of PDW pigs via whole-genome resequencing data; moreover, the results provide a basis for the national project for the conservation of this unique Chinese local population.

LncRNA XIST promotes migration of Wilms' tumor cells through modulation of microRNA-193a-5p.

OBJECTIVE: The aim of this study was to investigate long non-coding RNA (lncRNA) XIST expression in Wilms' tumor (WT) and to further explore its relationship with clinical features and prognosis of WT patients. PATIENTS AND METHODS: Quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) was carried out to examine the expression level of XIST in tumor tissue samples and paracancerous ones collected from 43 patients with renal cell carcinoma, and the interplay between XIST expression and clinical indicators, as well as prognosis of patients was analyzed. Meanwhile, XIST level in the nephroblast cancer cell line was further confirmed by qRT-PCR. In addition, XIST knockdown model was constructed using lentivirus in the WT cell lines, including HFWT and 17-94, and the influence of XIST on WT cell functions was analyzed through transwell assay. Finally, we investigated whether lncRNA XIST plays a role in the progression of WT by modulating microRNA-193a-5p. RESULTS: In this research, qRT-PCR results revealed a significantly higher expression of lncRNA XIST in tumor tissue specimens of patients with renal cell carcinoma than that in adjacent ones. Compared with patients with low expression of lncRNA XIST, those with high XIST expression had a higher incidence of distant metastasis and a lower overall survival rate. Compared with the negative control group, the metastatic ability of WT cells in the lncRNA XIST knockdown group was markedly weakened. In addition, the results of qPCR showed that mRNA expression of lncRNA XIST and microRNA-193a-5p were negatively correlated in renal cell carcinoma tissue specimens. At the same time, silencing microRNA-193a-5p reversed the reduced metastasis ability of WT cells induced by knockdown of XIST. CONCLUSIONS: LncRNA XIST expression is dramatically enhanced in WT tissues and cell lines, which is closely associated with the incidence of distant metastasis and patients' poor prognosis. In addition, we demonstrated that lncRNA XIST may accelerate the malignant progression of WT via inhibiting microRNA-193a-5p.

[Application and thinking of health standards related to public health in prevention and control of coronavirus disease 2019].

Objective: To systematically analyze the basic characteristics and contents of the current health standards for infectious disease, environmental health, school health and disinfection in the context of COVID-19 prevention and control, and provide support for the further optimization of epidemic prevention and control guidelines and reference for the revision and improvement of related health standards. Methods: Public health standards used in COVID-19 prevention and control were selected for a systematic comparison with "The Plan of COVID19 Prevention and Control (the 6(t)h Edition)" and other epidemic prevention and control guidelines from the perspectives of application scope and technical elements. Results: The current standards of public health are with scientificity, timeliness and feasibility. The application scope and technical elements of the current public health standards basically meet the needs of the prevention and control of COVID-19 epidemic, but the public health standardization system still needs improvement, and some public health standards need to be revised. Conclusions: The implementation of current public health standards can provide strong technical support for the prevention and control of COVID-19 epidemic. The experience obtained from COVID-19 epidemic prevention and control might promote the further improvement of the health standardization system.

[Application and thinking of health standards related to medical care and health information in prevention and control of COVID-19].

Objective: To compare the technical elements of health standards for nosocomial infection control, health protection, health information, and health emergency and biosafety in the context of the prevention and control of COVID-19, and provide support for the further optimization of the epidemic prevention and control guidelines. Methods: Above mentioned health standards used in COVID-19 prevention and control were collected for a systematic comparison with "Guidelines for Prevention and Control of COVID-19 in Medical Institutions" (the 1(st) Edition) from the perspective of technical elements. Results: The application scope and technical elements of the current health standards basically meet the needs for the prevention and control of COVID-19 epidemic. Conclusions: The implementation of the current health standards can provide strong technical support for the prevention and control of COVID-19 epidemic. The experience obtained in the epidemic prevention and control can also contribute to the further revision and improvement of the health standards.

The role of MiR-324-3p in polycystic ovary syndrome (PCOS) via targeting WNT2B.

OBJECTIVE: To investigate the expression of microRNA-324-3p (miR-324-3p) in polycystic ovary syndrome (PCOS) and its effects on the proliferation and apoptosis of ovarian granulosa cells. MATERIALS AND METHODS: A total of 60 Sprague-Dawley (SD) rats were randomly divided into normal group (n=30) and experimental group (n=30). Rats in the experimental group were intramuscularly injected with dehydroepiandrosterone (DHEA) (6 mg/100 g of body weight) and 0.2 mL oil for injection, while those in normal group were intramuscularly injected with 0.2 mL oil for injection. The ovarian tissues of PCOS model rats were removed to extract the total ribose nucleic acid (RNA). The expression of miR-324-3p was detected via reverse transcription-polymerase chain reaction (RT-PCR). Primary ovarian granulosa cells were isolated and cultured, and NC-miRNA and miR-324-3p mimic were transfected into cells. After 48 h, cell proliferation and apoptosis were detected via cell counting kit 8 (CCK-8) and flow cytometry assay, respectively. The targeted molecule of miR-324-3p was explored using bioinformatics, and dual-luciferase assay was performed to verify the effect of miR-324-3p on WNT2B expression. Granulosa cells were co-transfected with WNT2B-small-interfering RNA (siRNA) and miR-324-3p mimic, and then cell proliferation and apoptosis were detected via CCK-8 and flow cytometry assay, respectively. RESULTS: The expression of miR-324-3p in ovarian tissues of PCOS group was significantly lower than that of normal group (p < 0.01). After transfection with miR-324-3p mimic into granulosa cells, cell proliferation was significantly inhibited and cell apoptosis was promoted (p < 0.01). MiR-324-3p exerted its effect on granulosa cells by directly targeting WNT2B. Silencing WNT2B expression could reverse the effects of miR-324-3p on proliferation and apoptosis of granulosa cells (p < 0.05). CONCLUSIONS: The expression of miR-324-3p in the ovary of PCOS rats is decreased significantly. Overexpression of miR-324-3p can reduce the proliferation and induce the apoptosis of granulosa cells via targeting of WNT2B.

Melatonin promotes osteoblast differentiation of bone marrow mesenchymal stem cells in aged rats.

OBJECTIVE: The current study was to explore the effect of melatonin on osteoporosis and relevant mechanisms. MATERIALS AND METHODS: We performed micro-CT to detect bone microstructure and ELISA to detect the contents of osteocalcin (OCN) and bone alkaline phosphatase (BAP) in serum. Double fluorescence labeling of calcein and tetracycline and toluidine blue staining were used to determine morphological indexes of bone tissues. Alizarin red staining and Oil Red O staining were performed to recognize bone cells and adipocytes. RT-PCR was performed to determine the expression of osteoblast differentiation related genes. RESULTS: In the current study, data from micro-CT indicated that melatonin significantly increased the bone mass density (BMD), bone volume/tissue volume (BV/TV), trabecular number (Tb.N) and trabecular thickness (Tb.Th), and decreased the Structure Model Index (SMI) and trabecular Separation/Spacing (Tb.Sp) in elderly rats. Melatonin reduced calcium and phosphorus losses in urine and increased BAP and OCN levels in serum in elderly rats and increased bone formation rate (BFR) and bone mineralization rate (MAR) in elderly rats. Melatonin increased the number of osteoblasts in bone marrow and reduced the number of adipocytes in elderly rats. Melatonin also promoted the expression of osteogenic differentiation genes and suppressed the expression of adipogenic differentiation genes. CONCLUSIONS: WE suggest that melatonin could alleviate osteoporosis in aged rats' models probably by promoting osteoblast differentiation.

Association of genetic polymorphisms of de novo nucleotide biosynthesis with increased CHD susceptibility in the northern Chinese population.

Congenital heart disease (CHD) is one of most prevalent birth defects in the world. However, the underlying molecular mechanism(s) have not been fully understood. Here we report that increased CHD susceptibility is associated with genetic polymorphisms for de novo nucleotide biosynthesis in northern Chinese population, which has been reported with lower plasma folate levels. Nine tagSNPs of four genes (GART, ATIC, MTHFD1 and SHMT1) in de novo nucleotide biosynthesis were sequenced in 802 sporadic CHD patients and 1093 controls from two Han Chinese populations, located in north China (Shandong) and South China (Shanghai), respectively. Six SNPs were found to be significantly associated with CHDs or septation defects only in the Shandong population dataset, but none displayed significant association with any CHDs in the Shanghai population dataset as well as in the combined dataset. We also showed that the minor A allele of rs7279549 in GART reduced transcriptional activity and displayed lower affinity for unknown transcription factor(s), demonstrating the allele is a functional risk factor for CHD in Shandong population. Our study indicates that dysregulation of de novo nucleotide biosynthesis pathway may conditionally contribute to CHD pathogenesis in northern Chinese.

Raman fingerprint for semi-metal WTe2 evolving from bulk to monolayer.

Tungsten ditelluride (WTe2), a layered transition-metal dichalcogenide (TMD), has recently demonstrated an extremely large magnetoresistance effect, which is unique among TMDs. This fascinating feature seems to be correlated with its special electronic structure. Here, we report the observation of 6 Raman peaks corresponding to the A2(4), A1(9), A1(8), A1(5), and A1(2) phonons, from the 33 Raman-active modes predicted for WTe2. This provides direct evidence to distinguish the space group of WTe2 from those of other TMDs. Moreover, the Raman evolution of WTe2 from bulk to monolayer is clearly revealed. It is interesting to find that the A2(4) mode, centered at ~109.8 cm(-1), is forbidden in a monolayer, which may be attributable to the transition of the point group from C2v (bulk) to C2h (monolayer). Our work characterizes all observed Raman peaks in the bulk and few-layer samples and provides a route to study the physical properties of two-dimensional WTe2.

Strain-induced photoconductivity in thin films of Co doped amorphous carbon.

Traditionally, strain effect was mainly considered in the materials with periodic lattice structure, and was thought to be very weak in amorphous semiconductors. Here, we investigate the effects of strain in films of cobalt-doped amorphous carbon (Co-C) grown on 0.7PbMg(1/3)Nb(2/3)O3-0.3PbTiO3 (PMN-PT) substrates. The electric transport properties of the Co-C films were effectively modulated by the piezoelectric substrates. Moreover, we observed, for the first time, strain-induced photoconductivity in such an amorphous semiconductor. Without strain, no photoconductivity was observed. When subjected to strain, the Co-C films exhibited significant photoconductivity under illumination by a 532-nm monochromatic light. A strain-modified photoconductivity theory was developed to elucidate the possible mechanism of this remarkable phenomenon. The good agreement between the theoretical and experimental results indicates that strain-induced photoconductivity may derive from modulation of the band structure via the strain effect.

A dithiol glutaredoxin cDNA from sweet potato (Ipomoea batatas [L.] Lam): enzyme properties and kinetic studies.

Glutaredoxins (Grx) play an important role in reduction of protein glutathione mixed disulphides. An IbGrx cDNA (561 bp, EF362614) encoding a putative dithiol Grx was cloned from sweet potato (Ipomoea batatas [L.] Lam). The deduced amino acid sequence is conserved among the reported dithiol Grx, having a CGYC dithiol motif at the active site. A 3-D structural model was created based on the known crystal structure of a poplar Grx (GrxC1). To characterise the IbGrx protein, the coding region was subcloned into an expression vector and transformed into Escherichia coli. The recombinant His(6) -tagged IbGrx was expressed and purified by metal affinity chromatography. The purified enzyme showed a monomeric band, as demonstrated with 15% SDS-PAGE. The Michaelis constant (K(M) ) for ß-hydroxyethyl disulphide (HED) was 0.50 ± 0.08 Mm. The enzyme retained 60% activity at 80 °C for 16 min. The enzyme was active over a broad pH range from 6.0 to 11.0, and in the presence of imidazole up to 0.4 M. The enzyme was susceptible to protease.

Synthesis and characterization of fluorinated metal arsenates with a layer structure: (C4H12N2)(1.5)[M3F5(HAsO4)2(AsO4)] (M = Fe, Ga).

Two fluorinated metal arsenates, (C(4)H(12)N(2))(1.5)[M(3)F(5)(HAsO(4))(2)(AsO(4))] (M = Fe, Ga), have been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction, magnetic susceptibility, Mössbauer spectroscopy, and (71)Ga NMR spectroscopy. The two compounds are isostructural and crystallize in the monoclinic space group P2(1)/c (No. 14) with a = 8.394(1) A, b = 21.992(3) A, c = 10.847(1) A, beta = 96.188(2) degrees, and Z = 4 for the Fe compound, and a = 8.398(1) A, b = 21.730(3) A, c = 10.679(1) A, beta = 95.318(2) degrees, and Z = 4 for the Ga compound. The structure consists of infinite chains of corner-sharing MX(6) (X = O, F) octahedra and dimers of edge-sharing MO(3)F(3) octahedra, which are linked into two-dimensional sheets through arsenate tetrahedra with diprotonated piperazinium cations between the sheets. Magnetic susceptibility and Mössbauer spectroscopy confirm the presence of Fe(III). The (71)Ga MAS NMR spectrum clearly shows a line shape consisting of three components, corresponding to three crystallographically distinct Ga sites.

Central CGRP inhibits pancreatic enzyme secretion by modulation of vagal parasympathetic outflow.

Calcitonin gene-related peptide (CGRP) is a potent inhibitor of pancreatic enzyme secretion in vivo. Recent studies have shown that CGRP exerts its inhibitory action at a central vagal site. The present study investigates the mechanism responsible for the central action of CGRP. Rats were fitted with lateral cerebroventricular cannulas, using stereotaxic instruments, 4 days before pancreatic secretion studies. In anesthetized rats, administration of 2-deoxy-D-glucose (2-DG) (75 mg/kg iv) or CCK-8 (40 pmol. kg-1. h-1) produced a 100 and 75% increase in protein secretion, respectively, which was completely blocked by atropine. Intracerebroventricular (ICV) administration of CGRP (0.03-0.6 nmol/h) resulted in a dose-related inhibition of pancreatic protein secretion evoked by 2-DG or CCK-8. CGRP administered by the ICV route was 10-40 times more potent than CGRP given by the intravenous route. In contrast, ICV administration of CGRP had no significant effect on pancreatic protein secretion evoked by electrical vagal stimulation or bethanechol, which directly activates the pancreatic muscarinic receptor. Chemical sympathectomy induced by pretreatment with guanethedine (20 mg/kg ip, 2 days) or alpha-adrenergic receptor blockade with phentolamine did not alter the inhibitory effects of CGRP. We recently demonstrated that CCK stimulated the enteropancreatic neural pathways to mediate pancreatic secretion in rats with a chronic vagotomy. ICV-administered CGRP did not affect CCK-stimulated pancreatic secretion in rats with a chronic vagotomy. In conclusion, CGRP in the central nervous system inhibits pancreatic enzyme secretion stimulated by 2-DG and CCK-8, which act through vagal pathways. The inhibitory action of CGRP is not mediated by the sympathetic nervous system but appears to depend on intact vagus nerves.

[Studies on the mutagenicity of amrinone and milrinone].

The mutagenicity of domestic new drugs amrinone and milrinone were studied by Ames test, micronucleus test of mouse bone marrow and chromosome aberration assay in CHO cells. The results were as follows: neither amrinone nor milrinone was mutagenic in the Ames test; in chromosome aberration assay, both gave positive results; in mouse micronucleus test, amrinone gave a positive result when mice were exposed to 0.8 LD50 dose, but milrinone gave a negative result. These results suggested that amrinone and milrinone did not induce gene mutation, but amrinone induced chromosome damage both in vitro and in vivo, while the chromosome-damaging activity of milrinone in vitro may be minimized by biodetoxication in vivo.