Grain Boundaries and Gas Barrier Property of Graphene Revealed by Dark-Field Optical Microscopy

We demonstrate that dark-field (DF) optical microscopy is a powerful tool to visualize grain boundaries (GBs) and grain structure of graphene grown by chemical vapor deposition (CVD). Copper oxide nanoparticles sparsely formed along the graphene GBs by postgrowth mild oxidation allow one to determine the position and structure of the GBs by the DF microscope. As DF imaging offers a much higher sensitivity than bright-field (BF) microscopy, some GBs were observed even without the postgrowth oxidation. We found that periodic Cu steps formed below graphene can be also used to visualize the grain structure of the as-grown graphene by DF microscopy. Moreover, DF imaging is applicable to study of the gas barrier property of CVD graphene. Interestingly, the dissolved oxygen inside Cu foil enhanced oxidation of the Cu surface below graphene in spite of the fact that the graphene protects the underlying Cu from the exterior gas. Our work highlights the wide availability of DF optical microscopy in characterizing graphene and related two-dimensional materials grown on metal substrates

Utility of Ligand Effect in Homogenous Gold Catalysis: Enabling Regiodivergent π‑Bond-Activated Cyclization

Comprehensive utilization of both electronic and steric properties of ligands in homogeneous gold catalysis is achieved in the regio­divergent intra­molecular hydroarylation of alkynes. A flexible electron-deficient phosphite ligand, combined with the readily transformable directing group methoxyl amide, is attached to a cationic Au­(I) center in three-coordinate mode, affording sterically hindered <i>ortho</i>-position cyclization. Meanwhile, <i>para</i>-position cyclization is exclusively achieved with the assistance of a rigid electron-abundant phosphine ligand-based Au­(I) catalyst, in which ligands manifest the compensating effect for cyclization through steric hindrance and electronic properties. By combining gold with silver catalysts, tetrahydro­pyrrolo­quinolinones possessing a congested tricyclic structure are obtained via a proven Au/Ag relay catalytic process

Spatially Controlled Nucleation of Single-Crystal Graphene on Cu Assisted by Stacked Ni

In spite of recent progress of graphene growth using chemical vapor deposition, it is still a challenge to precisely control the nucleation site of graphene for the development of wafer-scale single-crystal graphene. In addition, the postgrowth patterning used for device fabrication deteriorates the quality of graphene. Herein we demonstrate the site-selective nucleation of single-crystal graphene on Cu foil based on spatial control of the local CH₄ concentration by a perforated Ni foil. The catalytically active Ni foil acts as a CH₄ modulator, resulting in millimeter-scale single-crystal grains at desired positions. The perforated Ni foil also allows to synthesize patterned graphene without any postgrowth processing. Furthermore, the uniformity of monolayer graphene is significantly improved when a plain Ni foil is placed below the Cu. Our findings offer a facile and effective way to control the nucleation of high-quality graphene, meeting the requirements of industrial processing

The Role of BRCA Status on the Prognosis of Patients with Epithelial Ovarian Cancer: A Systematic Review of the Literature with a Meta-Analysis

<div><p>Objective</p><p>The role of BRCA dysfunction on the prognosis of patients with epithelial ovarian cancer (EOCs) remains controversial. This systematic review tried to assess the role of BRCA dysfunction, including BRCA1/2 germline, somatic mutations, low BRCA1 protein/mRNA expression or BRCA1 promoter methylation, as prognostic factor in EOCs.</p><p>Methods</p><p>Studies were selected for analysis if they provided an independent assessment of BRCA status and prognosis in EOC. To make it possible to aggregate survival results of the published studies, their methodology was assessed using a modified quality scale.</p><p>Results</p><p>Of 35 evaluable studies, 23 identified BRCA dysfucntion status as a favourable prognostic factor. No significant differences were detected in the global score of quality assessment. The aggregated hazard ratio (HR) of overall survival (OS) of 34 evaluable studies suggested that BRCA dysfunction status had a favourable impact on OS (HR = 0.69, 95% CI 0.61–0.79), and when these studies were categorised into BRCA1/2 mutation and low protein/mRNA expression of BRCA1 subgroups, all of them demonstrated positive results (HR = 0.67, 95% CI: 0.57–0.78; HR = 0.62, 95% CI: 0.51–0.75; and HR = 0.51, 95% CI: 0.33–0.78, respectively), except for the subgroup of BRCA1 promoter methylation (HR = 1.59, 95% CI: 0.72–3.50). The meta-analysis of progression-free survival (PFS), which included 18 evaluable studies, demonstrated that BRCA dysfunction status was associated with a longer PFS in EOC (HR = 0.69, 95% CI: 0.63–0.76).</p><p>Conclusions</p><p>Patients with BRCA dysfunction status tend to have a better outcome, but further prospective clinical studies comparing the different BRCA statuses in EOC is urgently needed to specifically define the most effective treatment for the separate patient groups.</p></div

Characteristics of studies of patients with BRCA1/2 mutated ovarian cancer.

<p><b>Histology</b>: pathological histology of ovarian cancer, se = serous ovarian cancer, CCC = clear cell cancer of, Mu = mucinous ovarian cancer. all = almost all of the epithelial ovarian cancer types, including serous, mucinous, clear cell cancer, etc.</p><p><b>Laboratory methods</b>: laboratory methods used to detect BRCA1/2 mutation, PTT = Protein truncation test, SSCP = Single-Strand Conformation Polymorphism, seq = sequencing, DGGE = fluorescent multiplex denaturing gradient gel electrophoresis, MLPA = multiplex ligation-dependent probe amplification, DHPLC = Denaturing high performance liquid chromatography, RFLP = Restriction fragment length polymorphisms, F-CSGE = Fluorescence-based Conformation Sensitive Gel Electrophoresis.</p><p><b>Germline/somatic</b>: Germ = germline mutation, Mixed = BRCA1 germline/somatic mutation or BRCA1 promoter methylation.</p><p><b>Mutation types:</b> VUS = variants of unknown significance.</p><p><b>Treatment</b>: chemotherapy used, 1 = only Platinum was used, 2 = Platinum-based chemotherapy, 3 = other agents without Platinum, like Paclitaxel, etc.</p

Summary hazard ratios (HRs) and 95% confidence intervals (CIs) of ovarian cancer PFS for BRCA dysfunction status.

<p>Horizontal lines represent 95% CIs; diamonds represent summary estimates with corresponding 95% CIs. Test for heterogeneity: <i>P</i> = .118, <i>I</i>² = 29.3%. A fixed-effects model was used.</p

Characteristics of studies of patients of ovarian cancer with low BRCA1 mRNA expression or BRCA1 promoter methylation.

<p><b>Histology</b>: pathological histology of ovarian cancer, all = almost all of the epithelial ovarian cancer types, including serous, mucinous, clear cell cancer, etc.</p><p><b>Methods of methylation detecting</b>: methods of methylation detecting, MSP = methylation-specific polymerase chain reaction (PCR) analysis, MSRE = methylation-sensitive restriction enzyme digestion.</p><p><b>Treatment</b>: chemotherapy used, 2 = Platinum-based chemotherapy.</p

Proteomic Identification of Genes Associated with Maize Grain-Filling Rate

<div><p>Grain filling during the linear phase contributes most of the dry matter accumulated in the maize kernel, which in turn determines the final grain yield. Endosperms and embryos of three elite maize hybrids (Zhengdan 958, Nongda 108, and Pioneer 335) were sampled 17, 22, 25, and 28 days after pollination, during the linear phase of grain filling, for proteomic analysis to explore the regulatory factors critical for grain filling rate. In total, 39 and 43 protein spots that showed more than 2-fold changes in abundance at <i>P</i><0.01 between any two sampling stages in the endosperm and embryo were analyzed by protein mass spectrometry. The changing patterns in expression index of these proteins in the endosperm were evenly distributed, whereas up-regulation patterns predominated (74%) in the embryo. Functional analysis revealed that metabolism was the largest category, represented by nine proteins in the endosperm and 12 proteins in the embryo, of the proteins that significantly changed in abundance. Glycolysis, a critical process both for glucose conversion into pyruvate and for release of free energy and reducing power, and proteins related to redox homeostasis were emphasized in the endosperm. Additionally, lipid, nitrogen, and inositol metabolism related to fatty acid biosynthesis and late embryogenesis abundant proteins were emphasized in the embryo. One protein related to cellular redox equilibrium, which showed a more than 50-fold change in abundance and was co-localized with a quantitative trait locus for grain yield on chromosome 1, was further investigated by transcriptional profile implying consistent expression pattern with protein accumulation. The present results provide a first step towards elucidation of the gene network responsible for regulation of grain filling in maize.</p> </div

Summary hazard ratios (HRs) and 95% confidence intervals (CIs) of epithelial ovarian cancer OS for BRCA dysfunction status.

<p>Horizontal lines represent 95% CIs; diamonds represent summary estimates with corresponding 95% CIs. Test for heterogeneity: <i>P</i> = .000, <i>I</i>² = 61.7%. A random-effects model was used for analysis.</p

Representative 2-D maps.

<p>Maps from left to right represent expressed proteins at 17, 22, 25, and 28 days after pollination in the endosperm (A) and embryo (B) of Zhengdan 958, respectively. Differentially expressed protein spots at any two stages with more than 2-fold changes in expression are indicated by arrows with numeral.</p