Channel length dependence of the formation of quantum dots in GaN/AlGaN FETs

Quantum dots can be formed in simple GaN/AlGaN field-effect-transistors (FETs) by disordered potential induced by impurities and defects. Here, we investigate the channel length dependence of the formation of quantum dots. We observe decrease of the number of formed quantum dots with decrease of the FET channel length. A few quantum dots are formed in the case with the gate length of 0.05~$\mu$m and we evaluate the dot parameters and the disordered potential. We also investigate the effects of a thermal cycle and illumination of light, and reveal the change of the disordered potential.Comment: 10 pages, 5 figure

Molecular Identification of t(w5): Vps52 Promotes Pluripotential Cell Differentiation Through Cell-Cell Interactions

After implantation, pluripotent epiblasts are converted to embryonic ectoderm through cell-cell interactions that significantly change the transcriptional and epigenetic networks. An entree to understanding this vital developmental transition is the t(w5) mutation of the mouse t complex. This mutation produces highly specific defects in the embryonic ectoderm before gastrulation, leading to death of the embryonic ectoderm. Using a positional cloning approach, we have now identified the mutated gene, completing a decades-long search. The gene, vacuolar protein sorting 52 (Vps52), is a mouse homolog of yeast VPS52 that is involved in the retrograde trafficking of endosomes. Our data suggest that Vps52 acts in extraembryonic tissues to support the growth and differentiation of embryonic ectoderm via cell-cell interactions. It is also required in the formation of embryonic structures at a later stage of development, revealing hitherto unknown functions of Vps52 in the development of a multicellular organism.NSFCellular and Molecular Biolog

Superior vena cava syndrome causedby adult T-cell leukemia/lymphoma: a case report

A 74-year-old man with a smoking history was admitted for back and right arm pain. On examination, swelling of the face and arms were noted, and computed tomographic imaging of the chest demonstrated a bulky (10.0 x 7.2 cm) tumor in the right upper mediastinum. The lesion compressed the superior vena cava (SVC). Despite treatment, the patient died 5 months after the first admission. On autopsy, he was diagnosed that SVC syndrome caused by adult T-cell leukemia/lymphoma (ATL). ATL usually runs an aggressive course with multiple organs involving lymph nodes, liver, spleen, skin, lung, peripheral blood and bone marrow. Although it is extremely rare, SVC syndrome can appear as the earliest symptom of ATL

Neuronal XRN1 is required for maintenance of whole-body metabolic homeostasis

Control of mRNA stability and degradation is essential for appropriate gene expression, and its dysregulation causes various disorders, including cancer, neurodegenerative diseases, diabetes, and obesity. The 5′–3′ exoribonuclease XRN1 executes the last step of RNA decay, but its physiological impact is not well understood. To address this, forebrain-specific Xrn1 conditional knockout mice (Xrn1-cKO) were generated, as Xrn1 null mice were embryonic lethal. Xrn1-cKO mice exhibited obesity with leptin resistance, hyperglycemia, hyperphagia, and decreased energy expenditure. Obesity resulted from dysregulated communication between the central nervous system and peripheral tissues. Moreover, expression of mRNAs encoding proteins that regulate appetite and energy expenditure was dysregulated in the hypothalamus of Xrn1-cKO mice. Therefore, we propose that XRN1 function in the hypothalamus is critical for maintenance of metabolic homeostasis

The CCR4–NOT complex maintains liver homeostasis through mRNA deadenylation

The biological significance of deadenylation in global gene expression is not fully understood. Here, we show that the CCR4-NOT deadenylase complex maintains expression of mRNAs, such as those encoding transcription factors, cell cycle regulators, DNA damage response-related proteins, and metabolic enzymes, at appropriate levels in the liver. Liver-specific disruption of Cnot1, encoding a scaffold subunit of the CCR4-NOT complex, leads to increased levels of mRNAs for transcription factors, cell cycle regulators, and DNA damage response-related proteins because of reduced deadenylation and stabilization of these mRNAs. CNOT1 suppression also results in an increase of immature, unspliced mRNAs (pre-mRNAs) for apoptosis-related and inflammation-related genes and promotes RNA polymerase II loading on their promoter regions. In contrast, mRNAs encoding metabolic enzymes become less abundant, concomitant with decreased levels of these pre-mRNAs. Lethal hepatitis develops concomitantly with abnormal mRNA expression. Mechanistically, the CCR4-NOT complex targets and destabilizes mRNAs mainly through its association with Argonaute 2 (AGO2) and butyrate response factor 1 (BRF1) in the liver. Therefore, the CCR4-NOT complex contributes to liver homeostasis by modulating the liver transcriptome through mRNA deadenylation

Severe esophagitis directly induced by accumulation of crizotinib-residue at the esophageal mucosa proven with polarizing microscope examination

Crizotinib demonstrates dramatic effects for the patients with echinoderm microtubule-associated protein-like 4 (EML4)-anaplastic lymphoma kinase gene (ALK) fusion or c-ros oncogene 1 (ROS-1) fusion-positive lung cancer, with some characteristic toxicities. Although several studies reported that serious esophagitis was induced by crizotinib, the detailed mechanisms and ways to ameliorate the esophagitis have not been clarified. In this report, we report two cases with lung cancer who had been treated with crizotinib and developed severe esophagitis. Polarizing microscope examination clearly revealed that the accumulation of crizotinib-residue in the esophageal biopsy samples at the second anatomical narrowing of the esophagus in both cases. Since it seemed that the accumulation of crizotinib-residue in the esophageal mucosa directly caused the esophageal inflammation, we recommended taking crizotinib with a large amount of water (more than 200 ml) and to stay sitting upright for 30 minutes after intake. After that, the esophagitis gradually improved and the patients could continue taking crizotinib without dose reduction or withdrawal. Our experiences suggest that this crizotinib-induced esophagitis could be easily prevented by proper administration of crizotinib