Direct observation of single-atom defects in monolayer two-dimensional materials by using electron ptychography at 200 kV acceleration voltage.

Electron ptychography has emerged as a popular technology for high-resolution imaging by combining the high coherence of electron sources with the ultra-fast scanning electron coil. However, the limitations of conventional pixelated detectors, including poor dynamic range and slow data readout speeds, have posed restrictions in the past on conducting electron ptychography experiments. We used the Gatan STELA pixelated detector to capture sequential diffraction data of monolayer two-dimensional (2D) materials for ptychographic reconstruction. By using the pixelated detector and electron ptychography, we demonstrate the observation of the radiation damage at atomic resolution in Transition Metal Dichalcogenides (TMDs).

Lumican expression in pancreatic ductal adenocarcinoma.

BACKGROUND/AIMS: The present study was aimed to investigate lumican expression in and correlation with severity of pancreatic ductal adenocarcinoma (PDA). METHODOLOGY: We assessed mRNA expression and protein localization (using immunohistochemistry) in PDA samples collected from 260 patients. Additionally, we compared lumican expression with expression of Ki-67, VEGF and mutated p53 proteins, which are markers of cancer progression. RESULTS: Expression levels of lumican mRNA and protein in cancer tissue were significantly higher than those in tumor-adjacent tissue (t=5.69, p<0.05). The stromal expression of lumican in poorly differentiated cases was significantly higher at stage T4 than stage T2-3 (χ²=21.06, p<0.05); similarly, the stromal expression of lumican was significantly higher in TNM stage III-IV than in stage I-Il (χ²=17.01, p<0.05). Additionally, expression of Ki67 was higher in poorly differentiated cases than in highly-moderately differentiated cases (χ²=13.06, p<0.05). Finally, in highly-moderately differentiated samples, stromal expression of lumican was negatively correlated with expression of Ki-67, VEGF and mutated P53 (p<0.05). CONCLUSIONS: Lumican expression is higher in pancreatic ductal adenocarcinoma than in tumor-adjacent tissue, and the correlation of lumican expression with TNM stage in poorly differentiated samples, in contrast with its negative correlation with expression of Ki-67, VEGF and mutated P53 mutation in highly-moderately differentiated samples.

A simple and highly selective receptor for iodide in aqueous solution.

We synthesized a simple fluorescent receptor 3 bearing two boronic acid groups as recognition sites. The recognition behaviour of receptor 3 towards various anions was evaluated in THF/H(2)O (1:1, v/v) solution. Receptor 3 showed high selectivity for iodide among a series of anions. Fluorescence spectroscopy and computational calculations revealed that the electrostatic interaction played a crucial role in its high selectivity for iodide.

MicroRNA-125b expression in gastric adenocarcinoma and its effect on the proliferation of gastric cancer cells.

MicroRNAs exert regulatory effects on a number of genes, thereby contributing to both physiological and pathological processes. The functions of microRNAs in tumorigenesis are becoming increasingly clear. In the present study, we investigated the role of microRNA-125b (miR­125b), previously implicated in prostate and breast cancer, in gastric cancer, particularly regarding proliferation and apoptosis of gastric cancer cells. The expression of miR­125b was measured in 50 samples of gastric cancer tissues and corresponding para-cancerous tissues by real-time PCR. The levels of miR­125b expression in the gastric cancer tissues were significantly higher compared to the adjacent normal tissues (P<0.05). To begin to understand how the increased expression of miR­125b may promote gastric cancer, the miR­125b mimic was transfected into the gastric cancer cell line, HGC­27, for the determination of proliferation (CCK8) and apoptosis (Annexin V) by flow cytometry. The results demonstrated that the proliferation significantly increased and apoptosis significantly decreased in the HGC­27 cells following transfection with the miR­125b mimic, compared to the untreated and scramble­treated controls (P<0.05). Thus, miR­125b may act as an oncogene in gastric cancer by dysregulating gastric cell proliferation and apoptosis.

High levels of EphA3 expression are associated with high invasive capacity and poor overall survival in hepatocellular carcinoma.

Although EphA3 expression has been associated with progression or prognosis in several types of tumors, the role of EphA3 in hepatocellular carcinoma (HCC) remains unknown. This study sought to investigate the clinicopathological and prognostic relevance of EphA3 expression in HCC as well as the underlying mechanisms responsible. EphA3 protein was mainly localized within the cytoplasm and at the cell membrane. High EphA3 expression was correlated with tumor size, tumor grade, metastasis, venous invasion and AJCC TNM stage (P<0.05), and patients with high levels of EphA3 expression were at a significantly increased risk for shortened survival time (P<0.05). In vitro, the downregulation of EphA3 expression decreased the invasive capacity of HCC cells via the regulation of VEGF. EphA3 may represent a novel candidate marker for patient prognosis as well a molecular target for HCC therapy.

A pyrenyl-appended triazole-based ribose as a fluorescent sensor for Hg2+ ion.

For the efficient detection of toxic trace metal ions, two pyrenyl-appended triazole-based d-ribose fluorescent chemosensors 6 and 7 were prepared and their fluoroionophoric properties toward transition metal ions were investigated. Chemosensors 6 and 7 exhibit highly selective recognition toward Hg(2+) ion among a series of tested metal ions in CH(2)Cl(2)/MeOH solution. The association constants of 6 and 7 are calculated to be 1.73 × 10(5)M(-1) and 4.44 × 10(5)M(-1), respectively. Both 6 and 7 formed complexes with the Hg(2+) ion at a 1:1 ligand-to-metal ratio with a detection limit of 10-15 µM Hg(2+). Computational analysis demonstrated that the Hg(2+) ion occupied the coordination center of 6 with N(2) and N(3) atoms in two triazole groups, thus separating and distorting the two parallel pyrenes away from each other.

RNA interference-mediated control of hepatitis B virus and emergence of resistant mutant.

BACKGROUND & AIMS: Present therapy for chronic hepatitis B attains control only in limited proportions. Small interfering RNA (siRNA) offers a new tool with potential therapeutic applications for hepatitis B virus (HBV). Given the importance of sequence identity in the effectiveness of siRNA and the heterogeneity of HBV sequences among different isolates, a short hairpin RNA (shRNA)-expressing plasmid, pSuper/HBVS1, was developed to target a region conserved among major HBV genotypes and assess its effectiveness control of HBV. METHODS: HBV replication-competent plasmid was cotransfected with pSuper/HBVS1 to HuH-7 cells or to mice. The levels of viral proteins, RNA, and DNA were examined in transfected cells and animals. The effects of pSuper/HBVS1 on clinical isolates with genotypes B and C were also determined. RESULTS: pSuper/HBVS1 significantly decreased levels of viral proteins, RNA, and DNA for HBV genotype A in cell culture and in mice. Comparable suppressive effects were observed on clinical isolates of genotypes B and C. A clone with a silent mutation in the target region was identified from a patient with genotype C. This mutant revealed diminished sensitivity to pSuper/HBVS1 and could be selected out in the presence of pSuper/HBVS1 in cell culture. CONCLUSIONS: These findings indicated that shRNA could suppress HBV expression and replication for genotypes A, B, and C, promising an advance in treatment of HBV. However, the emergence of resistant mutants in HBV quasispecies should be considered.

Lineage differentiation-associated loss of adenoviral susceptibility and Coxsackie-adenovirus receptor expression in human mesenchymal stem cells.

Previous reports debated the effects of differentiation on adenoviral vector (AdV) transduction efficiency and Coxsackie-adenovirus receptor (CAR) expression. This prompted us to investigate the efficiency of AdV transduction and CAR expression in human mesenchymal stem cells (hMSCs) and their differentiated progeny. Current results revealed high efficiency (>90%) of AdV transduction and a consistent level of CAR expression in hMSCs by the use of AdV carrying the enhanced green fluorescent protein reporter gene. Competition of CAR with blocking monoclonal antibody RmcB resulted in a reduction in transduction efficiency, indicating the CAR involvement in transduction of hMSCs. The cells were then induced to differentiate into bone, fat, or neural cells, and results demonstrated that the differentiation was accompanied with a consistent decline in AdV transduction and a decrement in CAR expression. Cells were infected with AdV and then induced into differentiation, and results demonstrated that transduced cells preserved differentiation potentials and still had transgene expression in a subpopulation of cells for 4 weeks and even in tested lineage-specific differentiation. According to the present investigation, undifferentiated hMSCs can serve as a gene-delivering system, and gene transfer into hMSCs before differentiation can resolve the difficulties in transduction of their differentiated progeny.