First-principles study on structural, thermal, mechanical and dynamic stability of T'-MoS2

Using first-principles density functional theory calculations, we investigate the structure, stability, optical modes and electronic band gap of a distorted tetragonal MoS₂ monolayer (T'-MoS₂). Our simulated scanning tunnel microscopy (STM) images of T'-MoS₂ are dramatically similar to those STM images which were identified as K _x (H₂O) _y MoS₂ from a previous experimental study. This similarity suggests that T'-MoS₂ might have already been experimentally observed, but due to being unexpected was misidentified. Furthermore, we verify the stability of T'-MoS₂ from the thermal, mechanical and dynamic aspects, by ab initio molecular dynamics simulation, elastic constants evaluation and phonon band structure calculation based on density functional perturbation theory, respectively. In addition, we calculate the eigenfrequencies and eigenvectors of the optical modes of T'-MoS₂ at [Formula: see text] point and distinguish their Raman and infrared activity by pointing out their irreducible representations using group theory. At the same time, we compare the Raman modes of T'-MoS₂ with those of H-MoS₂ and T-MoS₂. Our results provide useful guidance for further experimental identification and characterization of T'-MoS₂.

[Polymorphism at the miR-502 binding site in the 3' untranslated region of SET8 gene is associated with the risk of clear cell renal cell carcinoma]

OBJECTIVE

To investigate the relationship between single nucleotide polymorphism of SET8 gene and the risk of clear cell renal cell carcinoma (CCRCC).

METHODS

We selected 140 CCRCC patients and 130 healthy controls in this case-control study.Genotype of single nucleotide polymorphism (rs16917496) at the miR-502 binding site in the 3'UTR of SET8 mRNA in the CCRCC patients and healthy controls was tested and the association between genotype and risk of cancer was assessed. The expression of SET8 was determined by immunohistochemistry and the relationship between expression of SET8 and genotype of rs16917496 was analyzed.

RESULTS

In the control group, CC, CT and TT genotypes were found in 30, 32 and 68 persons, respectively, while in the CCRCC patients, CC, CT and TT genotypes were found in 14 , 47 and 79 cases, respectively.The frequencies of rs16917496 CT and TT genotypes in the CCRCC group were significantly higher than those in the control group (P<0.05). Compared with the CC genotype, patients with CT and TT genotypes were more susceptible to develop CCRCC (P<0.05). CT and TT genotypes of rs16917496 at the miR-502 binding site of the SET8 gene were associated with expression of SET8.

CONCLUSIONS

Genotype of the SNP rs16917496 at the miR-502 binding site in the 3' untranslated region of the SET8 gene is associated with the expression of SET8 protein. Analysis of genetic polymorphisms in miRNA binding sites may help to identify the subgroups of population susceptible to CCRCC.

[Comparison on metabolic disorders and uric acid levels between patients with primary aldosteronism and essential hypertension]

Objective: To compare the incidence of metabolic disorders and uric acid (UA) levels between patients with primary aldosteronism (PA) and essential hypertension (EH), and to explore factors associated with UA levels in these patients. Methods: A total of 117 PA and 117 EH patients individually matched by sex, age, blood pressure and duration of hypertension were recruited from in-hospital patients who were hospitalized in our department because of suspicion of secondary hypertension from January 2008 to December 2014. Clinical data including metabolic disorders and UA levels were analyzed. Results: (1) Body mass index (BMI), waist circumference, plasma triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), free fatty acid (FFA) were significantly higher in EH than in PA group (all P<0.05). Prevalence of diabetes mellitus or impaired glucose tolerance (DM+ IGT) was significantly higher in EH than in PA group (41.9% (49/117) vs. 17.1% (20/117), P<0.01). The prevalence of metabolic syndrome (MS) was also significantly higher in EH than in PA group (51.3% (60/117) vs. 24.8% (29/117), P<0.01). (2) EH patients had higher homeostasis model assessment for insulin resistance (HOMA-IR) and lower insulin sensitivity index composite (ISI comp) than PA patients, but basic insulin secretion index (HOMA-β) and modified β cell function index (MBCI) were significantly lower in PA than in EH group (P<0.05). (3) With regard to target organs damages, PA patients revealed higher 24-hour urinary protein, urinary albumin excretion rate (UAER), urinary IgG, urinary α-1 microglobulin, left ventricular mass index and lower urine specific gravity than EH patients (all P<0.05). There was no significant difference in estimated glomerular filtration rate (eGFR) between two groups (P=0.103). (4) UA level was significantly lower in PA group than in EH group ((314.00±89.52) μmol/L vs. (379.16±101.25) μmol/L, P<0.01). Higher plasma aldosterone concentration and lower plasma renin activity were associated with lower UA level in PA group. Conclusions: Compared with sex, age and hypertension duration matched EH patients, PA patients revealed lower UA level and less severe abnormalities of glucose and lipid metabolism, but are associated with severer renal and cardiac damages. The reduced UA level in PA patients is possibly due to the high plasma aldosterone concentration and low plasma renin activity.

[Autophagy and its research progress in thyroid cancer]

To summarize the autophagy and its research progress in thyroid cancer.In combination with available literatures published in recent years involving the relationship between autophagy and thyroid cancer, the characteristics of autophagy, the role in thyroid cancer were reviewed. The changes of autophagy level will directly or indirectly participate in the pathogenesis and progression of thyroid cancer.Reagents regulating autophagy will have broad prospect of application in thyroid cancer therapy. The autophagy in the thyroid cancer is still poorly understood, and to clarify the molecular mechanism of autophagy and kill thyroid cancer cells by reasonable regulation of autophagy still needs more further studies.

Multidomain Skyrmion Lattice State in Cu2OSeO3

Magnetic skyrmions in chiral magnets are nanoscale, topologically protected magnetization swirls that are promising candidates for spintronics memory carriers. Therefore, observing and manipulating the skyrmion state on the surface level of the materials are of great importance for future applications. Here, we report a controlled way of creating a multidomain skyrmion state near the surface of a Cu2OSeO3 single crystal, observed by soft resonant elastic X-ray scattering. This technique is an ideal tool to probe the magnetic order at the L3 edge of 3d metal compounds giving an average depth sensitivity of ∼50 nm. The single-domain 6-fold-symmetric skyrmion lattice can be broken up into domains, overcoming the propagation directions imposed by the cubic anisotropy by applying the magnetic field in directions deviating from the major cubic axes. Our findings open the door to a new way to manipulate and engineer the skyrmion state locally on the surface or on the level of individual skyrmions, which will enable applications in the future.

[Effects of autologous adipose-derived stromal vascular fraction on erectile dysfunction of hypertensive rats]

OBJECTIVE

To study the effect of autologous adipose stromal vascular fraction (SVF) injection into corpora cavernosa on the hypertension-associated erectile dysfunction (ED) in rats and its possible mechanism.

METHODS

Healthy male spontaneously hypertensive rats (SHR) at 30-week (n=40) and homologous rats with normal blood pressure (WKY) (n=20) were selected. Noninvasive blood pressure meter was used to measure the systolic blood pressure (SBP) at the tail. Cervical subcutaneous injection of apomorphine was applied to test penile erectile function. The rats with ED were divided into hypertension-associated ED rats treated with autologous SVF injection into corpora cavernosa (ED-SHR-SVF group) (n=8) and hypertension-associated ED rats treated with phosphate buffered saline (PBS) injection into corpora cavernosa (ED-SHR-PBS group) (n=8). The intracavernosal pressure (ICP) was measured in each group. Western blot and RT-PCR were conducted to test protein and mRNA expressions of endothelial nitric oxide synthase (eNOS) in corpora cavernosa.

RESULTS

The tail SBP in SHR rats was significantly higher than that in WKY rats ((197.47±6.82) mmHg vs (125.23±4.65) mmHg, P<0.05). The erectile rate in SHR rats was 60% (24/40), and that in WKY rats was 100% (20/20). After 5 V electrical stimulation, the ICP in the ED-SHR-SVF group was significantly higher than in the ED-SHR-PBS group ((83.42±3.21) mmHg vs (52.37±3.11) mmHg, P<0.05). The protein and mRNA expressions of eNOS in the ED-SHR-SVF group were significantly higher than in the ED-SHR-PBS group (0.43±0.03 vs 0.18±0.05, 0.92±0.05 vs 0.41±0.06, both P<0.05).

CONCLUSIONS

High blood pressure can cause ED in rats, which could be mitigated by autologous SVF injection. The mechanism may be related to up-regulation of eNOS expression in corpus cavernosa.

[Incidence and influencing factors of term small for gestational age infants in China]

OBJECTIVE

To investigate the incidence and influencing factors of term small for gestational age infants (SGA ) in China.

METHODS

This study is a multicenter study. Data were collected from Chinese Neonatal Network with term infants, born from May 1st 2010 to February 28th 2014, from 83 nationwide hospitals.

RESULTS

A total of 170 565 neonates were recorded from 83 nationwide hospitals; 144 659 cases were term newborn, and 3 543 neonates were found to be term SGA. The incidence of term SGA was 2.45%. In term SGA, the girl's incidence (2.88%, 1 985/69 003) was higher than boy (2.05%, 1 531/74 707), P<0.001. Furthermore, the incidence of in vitro fertilization (IVF) and artificial fertilization of term SGA was 9.12% (66/724), which was higher than the natural conception (2.42%, 3 465/143 283), P<0.001. The incidence of term SGA in multiple births (30.37%, 741/2 440) was higher than that of single birth (1.97%, 2 787/141 366), P<0.001. The incidence of SGA with maternal age <18 years old was 4.86% (27/556) and was 3.20% (307/9 592) with maternal age > 35 years old, meanwhile both were higher than that with maternal age as 18-35 years old (2.39%, 3 197/133 662). The incidence of SGA with maternal occupation as farmers was 4.67% (854/18 284), which was significantly higher than other professions. The incidence of SGA with maternal education as illiterate and elementary education was 8.65% (187/2 162), 5.17% (397/7 678), respectively, both were significantly higher than those with mother graduated from university (1.72%, 853/49 692). Moreover, the geographical distribution of the main residence of the term SGA mothers showed Northeast Area (1.54%, 30/1 946)and East Area (2.21%, 1 267/57 334) had lower incidence of term SGA than those of Central South Area (2.71%, 493/18 223) and Southwest Area (3.67%, 876/23 852).

CONCLUSIONS

The incidence of term SGA was 2.45% in this study, which was influenced significantly by gender, IVF, multiple births, maternal factors (age, maternal occupation, level of education) and geographical distribution. This multicenter study with large data, to a certain extent, reflected status of the incidence and influencing factors of term SGA in China, which will help prevent and treat term SGA.

[Incidence and influencing factors of term small for gestational age infants in China]

OBJECTIVE

To investigate the incidence and influencing factors of term small for gestational age infants (SGA ) in China.

METHODS

This study is a multicenter study. Data were collected from Chinese Neonatal Network with term infants, born from May 1st 2010 to February 28th 2014, from 83 nationwide hospitals.

RESULTS

A total of 170 565 neonates were recorded from 83 nationwide hospitals; 144 659 cases were term newborn, and 3 543 neonates were found to be term SGA. The incidence of term SGA was 2.45%. In term SGA, the girl's incidence (2.88%, 1 985/69 003) was higher than boy (2.05%, 1 531/74 707), P<0.001. Furthermore, the incidence of in vitro fertilization (IVF) and artificial fertilization of term SGA was 9.12% (66/724), which was higher than the natural conception (2.42%, 3 465/143 283), P<0.001. The incidence of term SGA in multiple births (30.37%, 741/2 440) was higher than that of single birth (1.97%, 2 787/141 366), P<0.001. The incidence of SGA with maternal age <18 years old was 4.86% (27/556) and was 3.20% (307/9 592) with maternal age > 35 years old, meanwhile both were higher than that with maternal age as 18-35 years old (2.39%, 3 197/133 662). The incidence of SGA with maternal occupation as farmers was 4.67% (854/18 284), which was significantly higher than other professions. The incidence of SGA with maternal education as illiterate and elementary education was 8.65% (187/2 162), 5.17% (397/7 678), respectively, both were significantly higher than those with mother graduated from university (1.72%, 853/49 692). Moreover, the geographical distribution of the main residence of the term SGA mothers showed Northeast Area (1.54%, 30/1 946)and East Area (2.21%, 1 267/57 334) had lower incidence of term SGA than those of Central South Area (2.71%, 493/18 223) and Southwest Area (3.67%, 876/23 852).

CONCLUSIONS

The incidence of term SGA was 2.45% in this study, which was influenced significantly by gender, IVF, multiple births, maternal factors (age, maternal occupation, level of education) and geographical distribution. This multicenter study with large data, to a certain extent, reflected status of the incidence and influencing factors of term SGA in China, which will help prevent and treat term SGA.

Restriction-ligation-free (RLF) cloning: a high-throughput cloning method by in vivo homologous recombination of PCR products

In this study, we optimized a restriction-ligation-free (RLF) method to save time and cost of constructing multiple plasmids with the same gene insert, and examined the efficacy of RLF on high-throughput multi-plasmid cloning. This method utilizes the precise DNA repair and recombination systems within Escherichia coli, which allows to bypass the in vitro restriction and ligation enzyme reactions commonly included in routine cloning procedures. A homologous arm is linked to the 5'-end of the forward primer used to amplify both the target gene and vector. A different homologous arm is linked to the 5'-end of the reverse primer. Therefore, genes can be cloned into the vectors by homologous recombination after co-transformation of the amplified target gene and the linearized vector, which bear the same homologous arm on either end. More than twenty-four different plasmids were generated by this method, which uses two simple polymerase chain reaction steps. This method is highly efficient in cloning any gene of interest into any vector at any site without sequence constraints, as no restriction and ligation reactions are required.

Variability of cadmium, lead, and zinc tolerance and accumulation among and between germplasms of the fiber crop Boehmeria nivea with different root-types

Crop germplasms substantially vary in their tolerance for and accumulation of heavy metals, and assessment of this variability plays a significant role in selecting species to use in phytoremediation projects. Here, we examined germplasm-variations in cadmium (Cd), lead (Pb), and zinc (Zn) tolerance and accumulation in ramie (Boehmeria nivea), a fiber crop native to China, which has received little attention. In an 8-week greenhouse test, fourteen germplasms of ramie, among and within deep, middle, and shallow rooted-types, were compared for growth and metal accumulation traits. Results showed that both tolerance and accumulation traits varied across germplasms and rooted-types. The deep rooted-type germplasms produced more biomass and had higher tolerance to metals than the two others. In addition, considerable variations in metal accumulation were observed among plant organs (root, stem, and leaf), rooted-types, germplasms, and metal supply. However, the observed variations in metal tolerance and accumulation among both germplasms and rooted-types were not significant in most cases. In addition to supporting the idea of a certain degree of constitutional metal tolerance for ramie, our results also contribute to deep-rooted germplasms of ramie as a good candidate, rather than middle-/shallow- ones as a least-bad option, for the remediation of multi metal-contaminated soils.

Measurement of shear stress-mediated intracellular calcium dynamics in human dermal lymphatic endothelial cells

The shear stress applied to lymphatic endothelial cells (LEC) by lymph flow changes dramatically under normal conditions as well as in response to disease conditions and immune reactions. In general, LEC are known to regulate the contraction frequency and strength of lymphatic pumping in response to shear stress. Intracellular calcium concentration ([Ca(2+)]i) is an important factor that regulates lymphatic contraction characteristics. In this study, we measured changes in the [Ca(2+)]i under different shear stress levels and determined the source of this calcium signal. Briefly, human dermal LEC were cultured in custom-made microchannels for 3 days before loading with 2 µM fura-2 AM, a ratiometric calcium dye to measure [Ca(2+)]i. Step changes in shear stress resulted in a rapid increase in [Ca(2+)]i followed by a gradual return to the basal level and sometimes below the initial baseline (45.2 ± 2.2 nM). The [Ca(2+)]i reached a peak at 126.2 ± 5.6 nM for 10 dyn/cm(2) stimulus, whereas the peak was only 71.8 ± 5.4 nM for 1 dyn/cm(2) stimulus, indicating that the calcium signal depends on the magnitude of shear stress. Removal of the extracellular calcium from the buffer or pharmocological blockade of calcium release-activated calcium (CRAC) channels significantly reduced the peak [Ca(2+)]i, demonstrating a role of extracellular calcium entry. Inhibition of endoplasmic reticulum (ER) calcium pumps showed the importance of intracellular calcium stores in the initiation of this signal. In conclusion, we demonstrated that the shear-mediated calcium signal is dependent on the magnitude of the shear and involves ER store calcium release and extracellular calcium entry.

Non-association of MMP-9 -1562C/T polymorphism with preeclampsia risk: evidence from a meta-analysis

Individual genetic association studies examining the relationship between the MMP-9 -1562C/T polymorphism (rs3918242) and preeclampsia risk have yielded inconsistent results.

OBJECTIVE

This study aims to evaluate the association between the MMP-9 -1562C/T polymorphism and preeclampsia risk using meta-analysis.

MATERIALS AND METHODS

Relevant studies were identified by searching PubMed database. Data were extracted and statistical analysis was performed using STATA 12.0 software. A total of six publications involving 871 cases and 845 controls were included in this meta-analysis.

RESULTS

Combined analysis revealed no association between the MMP-9 -1562C/T polymorphism and preeclampsia risk (allelic model: OR = 1.10, 95% CI 0.86-1.41, Pheterogeneity = 0.07; recessive model: OR = 0.38, 95% CI 0.14-1.01, Pheterogeneity = 0.64; dominant model: OR = 1.09, 95% CI 0.70-1.69, Pheterogeneity = 0.01; homozygous model: OR = 0.41, 95% CI 0.15-1.09, Pheterogeneity = 0.67; heterozygous model: OR = 1.36, 95% CI 0.80-2.29, Pheterogeneity = 0.01). Similarly, subgroup analysis by ethnicity showed that MMP-9 -1562C/T polymorphism was not associated with preeclampsia risk in Brazilian (allelic model: OR = 1.37, 95% CI 0.92-2.05, Pheterogeneity = 0.61; recessive model: OR = 0.80, 95% CI 0.18-3.57, Pheterogeneity = 0.58; dominant model: OR = 1.12, 95% CI 0.60-2.10, Pheterogeneity = 0.03; homozygous model: OR 0.87, 95% CI 0.19-3.94, Pheterogeneity = 0.62; heterozygous model: OR = 1.55, 95% CI 0.99-1.75, Pheterogeneity = 0.32).

CONCLUSION

This meta-analysis indicated that MMP-9 -1562C/T polymorphism was not associated with preeclampsia risk. However, large well-designed, multi-center epidemiological studies should be carried out in these and other ethnic populations to confirm our findings.

Effects of isobutyrate supplementation on ruminal microflora, rumen enzyme activities and methane emissions in Simmental steers

The objective of this study was to evaluate the effects of isobutyrate supplementation on rumen microflora, enzyme activities and methane emissions in Simmental steers consuming a corn stover-based diet. Eight ruminally cannulated Simmental steers were used in a replicated 4 × 4 Latin square experiment. The treatments were control (without isobutyrate), low isobutyrate (LIB), moderate isobutyrate (MIB) and high isobutyrate (HIB) with 8.4, 16.8 and 25.2 g isobutyrate per steer per day respectively. Isobutyrate was hand-mixed into the concentrate portion. Diet consisted of 60% corn stover and 40% concentrate [dry matter (DM) basis]. Dry matter intake (averaged 9 kg/day) was restricted to a maximum of 90% of ad libitum intake. Population of total bacteria, cellulolytic bacteria and anaerobic fungi were linearly increased, whereas that of protozoa and total methanogens was linearly reduced with increasing isobutyrate supplementation. Real-time PCR quantification of population of Ruminococcus albus, Ruminococcus flavefaciens, Butyrivibrio fibrisolvens and Fibrobacter succinogenes was linearly increased with increasing isobutyrate supplementation. Activities of carboxymethyl cellulase, xylanase and β-glucosidase were linearly increased, whereas that of protease was linearly reduced. Methane production was linearly decreased with increasing isobutyrate supplementation. Effective degradabilities of cellulose and hemicellulose of corn stover were linearly increased, whereas that of crude protein in diet was linearly decreased with increasing isobutyrate supplementation. The present results indicate that isobutyrate supplemented improved microflora, rumen enzyme activities and methane emissions in steers. It was suggested that the isobutyrate stimulated the digestive micro-organisms or enzymes in a dose-dependent manner. In the experimental conditions of this trial, the optimum isobutyrate dose was approximately 16.8 g isobutyrate per steer per day.

Structural, electrical and optical properties of Mg-doped CuAlO2 films by pulsed laser deposition

P-type Mg doped CuAlO₂ films with high crystallinity are prepared by pulsed laser deposition followed by annealing, and exhibit enhanced conductivity and tunable optical band gaps.

Aberrant promoter methylation of the CD4 gene in peripheral blood cells of mastitic dairy cows

Bovine mastitis is the most common and costly disease of dairy cattle. Cluster of differentiation 4 (CD4) is closely related to the immune response in mastitis. We quantified promoter CpG methylation levels of the CD4 gene in Chinese Holsteins with clinical mastitis (CM) and in healthy controls; these levels were quantitatively detected with bisulfite pyrosequencing assays and confirmed by cloning sequencing. We found that the bovine CD4 promoter had 16% more methyl groups in the cows with CM (75.0 ± 5.8%) compared to the controls (59.0 ± 8.5%). The decreased expression level of CD4 in CM cows may be downregulated by the increased DNA methylation levels in the CD4 promoter. Two-dimensional hierarchical clustering analyses showed large differences in promoter CD4 methylation between mastitic and healthy cows; the dendrogram clearly distinguished the cows with clinical mastitis from healthy controls based on methylation levels. The DNA methylation level of the CD4 gene was strongly influenced by mastitis status in all comparisons. We suggest that the DNA methylation level of the CD4 promoter can be used as a molecular marker for clinical mastitis in dairy cows.

Biochemical parameters of Saccharopolyspora erythraea during feeding ammonium sulphate in erythromycin biosynthesis phase

The physiology of feeding ammonium sulphate in erythromycin biosynthesis phase of Saccharopolyspora erythraea on the regulation of erythromycin A (Er-A) biosynthesis was investigated in 50 L fermenter. At an optimal feeding ammonium sulphate rate of 0.03 g/L per h, the maximal Er-A production was 8281 U/mL at 174 h of growth, which was increased by 26.3% in comparison with the control (6557 U/mL at 173 h). Changes in cell metabolic response of actinomycete were observed, i.e. there was a drastic increase in the level of carbon dioxide evolution rate and oxygen consumption. Assays of the key enzyme activities and organic acids of S. erythraea and amino acids in culture broth revealed that cell metabolism was enhanced by ammonium assimilation, which might depend on the glutamate transamination pathway. The enhancement of cell metabolism induced an increase of the pool of TCA cycle and the metabolic flux of erythromycin biosynthesis. In general, ammonium assimilation in the erythromycin biosynthesis phase of S. erythraea exerted a significant impact on the carbon metabolism and formation of precursors of the process for dramatic regulation of secondary metabolites biosynthesis.

Enhanced superconductivity by rare-earth metal doping in phenanthrene

We successfully synthesized La- and Sm-doped phenanthrene powder samples and observed superconductivity in them at T(c) around 6 K. The T(c)s are 6.1 K for La(1) phenanthrene and 6.0 K for Sm(1) phenanthrene, which are enhanced by about 1 and 0.5 K compared to those in A(3) phenanthrene (A = K and Rb) and in Ae(1.5) phenanthrene (Ae = Sr and Ba) superconductors, respectively. The superconductive shielding fractions for La(1) phenanthrene and Sm(1) phenanthrene are 46.1% and 49.8% at 2 K, respectively. The small effect of doping with the magnetic ion Sm(3+) on T(c) and the positive pressure dependence coefficient of T(c) strongly suggest unconventional superconductivity in the doped phenanthrene superconductors. The charge transfer to organic molecules from dopants of La and Sm induces a redshift of 7 cm(-1) per electron for the mode at 1441 cm(-1) in the Raman spectra, which is almost the same as those observed in A(3) phenanthrene (A = K and Rb) and Ae(1.5) phenanthrene (Ae = Sr and Ba) superconductors.