Role of Edge Reconstruction in the Synthesis of Few-Layer Black Phosphorene

Recent advancements in preparing few-layer black phosphorene (BP) are hindered by edge reconstruction challenges. Our previous studies have revealed the factors contributing to the difficulty of growing few-layer BP. In this study, we have successfully identified three reconstructed edges in bi- and multilayer BP through a combination of the crystal structure analysis by particle swarm optimization (CALYPSO) global structure search and density functional theory (DFT). Notably, the reconstruction between adjacent layers proves more beneficial than self-passivation or maintaining pristine edges. Among the reconstructed edges, the reconstructed ZZ edge is the most stable, regardless of the number of layers. Calculated electronic band structures reveal a significant transition in the electronic properties of black phosphorus nanoribbons (BPNRs), changing from metallic to semiconducting. This insight not only enhances the understanding of the fundamental properties of BP but also provides valuable theoretical guidance for the experimental growth of BPNRs or black phosphorus nanowires (BPNWs).

Promoter hypomethylation and increased maspin expression in preeclamptic placentas in a Chinese population

OBJECTIVE

Preeclampsia is thought to begin with shallow trophoblast invasion and inadequate spiral artery remodeling. Maspin, a tumor-suppressor gene, plays a regulatory role in trophoblast invasion and motility. The tissue-specific methylation of the maspin promoter can regulate maspin gene expression in various cancers. We sought to detect maspin gene expression and assess the degrees of methylation of maspin promoter regions in preeclamptic placentas in the Han Chinese population and to investigate the potential role of maspin in the pathophysiology of preeclampsia.

METHODS

We conducted RT-PCR, immunohistochemistry and western blotting to characterize maspin gene expression and protein levels in the placentas from normal and preeclamptic pregnancies. Finally, using methylation-specific PCR and bisulfite sequencing PCR, we detected the degrees of methylation of the promoter regions of maspin in each of the two studied groups.

RESULTS

Maspin expression was increased at the mRNA and protein levels in the preeclamptic placentas compared to the control group. Maspin immunohistochemical staining revealed positive staining in the syncytio-cytotrophoblast layers and more diffuse staining in the preeclamptic group. The mean methylation level of the analyzed promoter region was significantly hypomethylated in the preeclamptic placentas compared to the control placentas, pointing to a negative relationship between maspin promoter methylation and gene expression.

DISCUSSION

Hypomethylation of the maspin promoter results in increased expression of maspin in preeclamptic placentas, which suggests a negative relationship between maspin methylation and maspin expression in this Han Chinese population. Thus, maspin is likely involved in the etiology of preeclampsia.

High leptin level and leptin receptor Lys656Asn variant are risk factors for preeclampsia

The aim of this study was to investigate the relationship between the leptin receptor (LEPR) polymorphism/serum leptin level and preeclampsia. The prevalence of a single nucleotide polymorphism in the LEPR gene exon 14 at -656 and the serum leptin concentrations in 97 preeclamptic pregnant mothers were compared to those of 110 healthy controls. The Lys656Asn genotype and Lys656Asn + Asn656Asn frequencies in the LEPR gene were significantly more prevalent in preeclampsia mothers than in controls (P < 0.05). The serum leptin levels of preeclampsia cases were significantly higher than those of controls. In addition, there were higher serum leptin levels in individuals with the GC + CC genotype both in the total cohort and in women with preeclampsia than in those with the GG genotype. Our findings suggest that the Lys656Asn polymorphism is a functional variant in the LEPR, which can affect the interaction of leptin and its receptor. Furthermore, high leptin level and the LEPR variant are risk factors for preeclampsia in Chinese women.

[Significance of sex hormone binding globulin and free androgen index in the estimation of androgenic cases]

Hormone analyses for hirsute women suggested that free testosterone was most revealing in biological effects and sex-hormone-binding globulin (SHBG) was quantitatively persuative. Presented in this paper are the measurements of testosterone, androstendion, dehydroepiandrosterone-sulfate (DHAS), SHBG, androstandiol and free androgen index (FAI) in 51 women with hirsutism. 92% of the hirsute women with elevated androgen level showed decrease in SHBG values and increase in FAI. 17 females with hirsutism revealed abnormally high androstandiol values which were highly related to the values of total and free testosterone (r = 0.78, r = 0.80, respectively). It is suggested that in clinical practice SHBG and FAI should also be measured besides testosterone and DHAS.