First-Principles Study of Ultrathin Molybdenum Sulfides Nanowires:Electronic and Catalytic Hydrogen Evolution Properties

Molybdenum sulfides nanomaterials, such as one-dimensional (1D) nanotubes, nanoribbons, and two-dimensional (2D) nanosheets, have attracted intensive research interests for their novel electronic, optical, and catalytic properties. On the basis of first-principles calculation, here, we report a new series of 1D ultrathin molybdenum sulfides nanowires, including Mo2S6、Mo3S6 and Mo6S10 nanowires. Our results demonstrate that these ultrathin nanowires are both thermal and lattices dynamically stable, confirmed with the calculated phonon spectrum and Born-Oppenheimer molecular dynamic simulation at the temperature up to 600 K. The calculated elastic constant is 21.33, 103.22, and 163.00 eV/■ for Mo2S6, Mo3S6, and Mo6S10 nanowires, respectively. Mo2S6 and Mo3S6 nanowires are semiconductors with band gap of 1.55 and 0.46 eV, while Mo6S10 nanowires is metal, implying their potential applications in electronics and optoelectronics. In particular, ultrathin molybdenum sulfides nanowires can be used as catalysts for hydrogen evolution reaction. The calculated Gibbs free energy change for hydrogen evolution is about -0.05 eV for Mo2S6 nanowire, comparable with those of Pt and H-MoS2. The prediction of these 1D molybdenum sulfides nanowires may enrich the 1D family molybdenum sulfides and make a supplement to understand the high performance of hydrogen evolution reaction in transition-metal dichalcogenides.

Association between MTHFR c.677C>T variant and erectile dysfunction among males attending fertility clinic

Genetic risk factors have been shown to contribute to the development of sexual dysfunction.However,the role of methylenetetrahydrofolate reductase(MTHFR)gene variants in the risk of erectile dysfunction(ED)remains unclear.In this study,we recruited 1254 participants who underwent ED assessed by the International Index of Erectile Function-5.The MTHFR c.677C>T variant was also measured by fluorescence polymerase chain reaction(PCR).No significant difference in the genotypic frequency of the MTHFR C677T polymorphism(CC,CT,and TT)was observed between men from the ED and non-ED groups.In addition,on binary logistic regression analysis,both crude and adjusted models showed that the risk of ED was not significantly associated with the C677T polymorphism.Interestingly,a significantly higher frequency of the 677TT polymorphism was found in severe and moderate ED(P=O.02).The positive correlation between the MTHFR 677TT polymorphism and severe ED was confirmed by logistic regression analysis,even after adjusting for potential confounders(odds ratio[OR]=2.46,95%confidence interval[CI]:1.15-5.50,P=0.02).These findings suggest a positive correlation between the MTHFR 677TT polymorphism and the risk of severe ED.Identification of MTHFR gene polymorphisms may provide complementary information for ED patients during routineclinicaldiagnosis.

Semen parameters in men recovered from COVID-19

The novel coronavirus disease(COVID-19)pandemic is emerging as a global health threat and shows a higher risk for men than women.Thus far,the studies on andrological consequences of COVID-19 are limited.To ascertain the consequences of COVID-19 on sperm parameters after recovery,we recruited 41 reproductive-aged male patients who had recovered from COVID-19,and analyzed their semen parameters and serum sex hormones at a median time of 56 days after hospital discharge.For longitudinal analysis,a second sampling was obtained from 22 of the 41 patients after a median time interval of 29 days from first sampling.Compared with controls who had not suffered from COVID-19,the total sperm count,sperm concentration,and percentages of motile and progressively motile spermatozoa in the patients were significantly lower at first sampling,while sperm vitality and morphology were not affected.The total sperm count,sperm concentration,and number of motile spermatozoa per ejaculate were significantly increased and the percentage of morphologically abnormal sperm was reduced at the second sampling compared with those at first in the 22 patients examined.Though there were higher prolactin and lower progesterone levels in patients at first sampling than those in controls,no significant alterations were detected for any sex hormones examined over time following COVID-19 recovery in the 22 patients.Although it should be interpreted carefully,these findings indicate an adverse but potentially reversible consequence of COVID-19 on sperm quality.

Biallelic mutations in WDR12 are associated with male infertility with tapered-head sperm

Teratozoospermia is a rare disease associated with male infertility.Several recurrent genetic mutations have been reported to be associated with abnormal sperm morphology,but the genetic basis of tapered-head sperm is not well understood.In this study,whole-exome sequencing(WES)identified a homozygous WD repeat domain 12(WDR12;p.Ser162Ala/c.484T>G)variant in an infertile patient with tapered-head spermatozoa from a consanguineous Chinese family.Bioinformatic analysis predicted this mutation to be a pathogenic variant.To verify the effect of this variant,we analyzed WDR12 protein expression in spermatozoa of the patient and a control individual,as well as in the 293T cell line,by Western blot analysis,and found that WDR12 expression was significantly downregulated.To understand the role of normal WDR12,we evaluated its mRNA and protein expression in mice at different ages.We observed that WDR12 expression was increased in pachytene spermatocytes,with intense staining visible in round spermatid nuclei.Based on these results,the data suggest that the rare biallelic pathogenic missense variant(p.Ser162Ala/c.484T>G)in the WDR12 gene is associated with tapered-head spermatozoa.In addition,after intracytoplasmic sperm injection(ICSI),a successful pregnancy was achieved.This finding indicates that infertility associated with this WDR12 homozygous mutation can be overcome by ICSI.The present results may provide novel insights into understanding the molecular mechanisms of male infertility.

MBOAT1 homozygous missense variant causes nonobstructive azoospermia

Nonobstructive azoospermia(NOA)is a common cause of infertility and is defined as the complete absence of sperm in ejaculation due to defective spermatogenesis.The aim of this study was to identify the genetic etiology of NOA in an infertile male from a Chinese consanguineous family.A homozygous missense variant of the membrane-bound O-acyltransferase domain-containing 1(MBOAT1)gene(c.770C>T,p.Thr257Met)was found by whole-exome sequencing(WES).Bioinformatic analysis also showed that this variant was a pathogenic variant and that the amino acid residue in MBOAT1 was highly conserved in mammals.Quantitative polymerase chain reaction(Q-PCR)analysis showed that the mRNA level of MBOAT1 in the patient was 22.0%lower than that in his father.Furthermore,we screened variants of MBOAT1 in a broader population and found an additional homozygous variant of the MBOAT1 gene in 123 infertile men.Our data identified homozygous variants of the MBOAT1 gene associated with male infertility.This study will provide new insights for researchers to understand the molecular mechanisms of male infertility and will help clinicians make accurate diagnoses.