Histones function both positively and negatively in the regulation of gene expression, mainly governed by post-translational modifications on specific amino acid residues. Although histone ...modifications are not necessarily prerequisite codes, they may still serve as good epigenetic indicators of chromatin state associated with gene activation or repression. In particular, six emerging classes of histone H3 modifications are subjected for epigenome profiling by the International Human Epigenome Consortium. In general, transcription start sites of actively transcribed genes are marked by trimethylated H3K4 (H3K4me3) and acetylated H3K27 (H3K27ac), and active enhancers can be identified by enrichments of both monomethylated H3K4 (H3K4me1) and H3K27ac. Gene bodies of actively transcribed genes are associated with trimethylated H3K36 (H3K36me3). Gene repression can be mediated through two distinct mechanisms involving trimethylated H3K9 (H3K9me3) and trimethylated H3K27 (H3K27me3). Enrichments of these histone modifications on specific loci, or in genome wide, in given cells can be analyzed by chromatin immunoprecipitation (ChIP)-based methods using an antibody directed against the site-specific modification. When performing ChIP experiments, one should be careful about the specificity of antibody, as this affects the data interpretation. If cell samples with preserved histone-DNA contacts are available, evaluation of histone modifications, in addition to DNA methylaion, at specific gene loci would be useful for deciphering the epigenome state for human genetics studies.
The sol–gel state of smectite clay dispersions varies with the volume fraction of clay and electrolyte concentration. In this study, it was elucidated that the drying patterns of droplets from four ...types of smectite clay dispersions vary according to their sol–gel states. Droplets in the sol state exhibited a ring-shaped pattern, while those in the gel state showed a bump-shaped pattern. Near the boundary between the sol and gel states, patterns featuring both ring and bump structures were observed regardless of whether the droplets were on the sol or gel side. When guest particles or molecules were introduced into the clay dispersion, they dispersed uniformly within the system, and the drying pattern depended on the sol–gel state of the droplets. These findings suggest that the presence or absence of convection within the droplets during drying governs the drying pattern.
Photoelectron emission is crucial to electric charging of dust particles around main-sequence stars and gas heating in various dusty environments. An estimate of the photoelectric processes contains ...an ill-defined parameter called the photoelectric quantum yield, which is the total number of electrons ejected from a dust particle per absorbed photon. Here we revisit the so-called small particle effect of photoelectron emission and provide an analytical model to estimate photoelectric quantum yields of small dust particles in sizes down to nanometers. We show that the small particle effect elevates the photoelectric quantum yields of nanoparticles up to by a factor of 103 for carbon, water ice, and organics, and a factor of 102 for silicate, silicon carbide, and iron. We conclude the surface curvature of the particles is a quantity of great importance to the small particle effect, unless the particles are submicrometers in radius or larger.
Although animal experiments are indispensable for preclinical screening in the drug discovery process, various issues such as ethical considerations and species differences remain. To solve these ...issues, cell-based assays using human-derived cells have been actively pursued. However, it remains difficult to accurately predict drug efficacy, toxicity, and organs interactions, because cultivated cells often do not retain their original organ functions and morphologies in conventional in vitro cell culture systems. In the μTAS research field, which is a part of biochemical engineering, the technologies of organ-on-a-chip, based on microfluidic devices built using microfabrication, have been widely studied recently as a novel in vitro organ model. Since it is possible to physically and chemically mimic the in vitro environment by using microfluidic device technology, maintenance of cellular function and morphology, and replication of organ interactions can be realized using organ-on-a-chip devices. So far, functions of various organs and tissues, such as the lung, liver, kidney, and gut have been reproduced as in vitro models. Furthermore, a body-on-a-chip, integrating multi organ functions on a microfluidic device, has also been proposed for prediction of organ interactions. We herein provide a background of microfluidic systems, organ-on-a-chip, Body-on-a-chip technologies, and their challenges in the future.
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A novel method has been proposed to induce rapid upward movement of colloidal particles with a density lower than water by applying an electric field of several V/mm in water. This phenomenon, known ...as the Electrically Induced Rapid Sedimentation (ERS) effect, marks the first occurrence of ‘rapid upward movement of colloidal particles’ within the scope of this phenomenon. Focusing on hollow particles, an investigation of the ERS effect was conducted through transmittance measurement. The hollow particles in water showed a drastic increase in ascending velocity through the application of an electric field. The ascending velocity raised when increasing the electric field strength. Utilizing a quasi-DC electric field (an extremely low-frequency AC electric field), aggregate structures were captured for the first time.
On the basis of the most recent view on the local interstellar medium consisting of a single continuous cloud, termed the Local Cloud, we study the destruction of interstellar dust by the propagation ...of a shock wave in the Local Cloud. We survey gas-phase column densities of dust-forming elements in the literature to determine how the dust destruction fraction varies with the angle from the minor axis of the cloud. Our results indicate that the propagation of a shock wave destroyed approximately 20 per cent of interstellar dust towards the minor axis of the cloud pointing near the anti-apex of motion with a shock of <100 km s−1, weaker than previously expected. The gas-to-dust ratio of the Local Cloud is approximately 120 towards the apex of cloud motion and organic-forming elements occupy 40 per cent of the mass in the dust phase. We find that a correlation in the gas-phase abundances between silicon and magnesium is consistent with the destruction of silicate grains with enstatite stoichiometry. We also derive the most plausible composition of interstellar dust from the dust-phase elemental abundances and the correlations between the dust-forming elements. We suggest that the major constituents of interstellar dust are organic materials, magnesium silicates and iron alloys, while the minor ones are spinels and iron sulphides. Since no organic materials have been detected in the grains that penetrate into the Solar system, we claim that the composition of interstellar dust may not remain intact en route to the inner Solar system.
Chronic active Epstein-Barr virus (CAEBV) disease is a rare disorder in which persons are unable to control infection with the virus. The disease is progressive with markedly elevated levels of EBV ...DNA in the blood and infiltration of organs by EBV-positive lymphocytes. Patients often present with fever, lymphadenopathy, splenomegaly, EBV hepatitis, or pancytopenia. Over time, these patients develop progressive immunodeficiency and if not treated, succumb to opportunistic infections, hemophagocytosis, multiorgan failure, or EBV-positive lymphomas. Patients with CAEBV in the United States most often present with disease involving B or T cells, while in Asia, the disease usually involves T or NK cells. The only proven effective treatment for the disease is hematopoietic stem cell transplantation. Current studies to find a cause of this disease focus on immune defects and genetic abnormalities associated with the disease.
Objective: Acute exposure to hypoxia generally increase the ventilation. However, some of COVID-19 patients who suffer from pneumonia are characterized by hypoxic ventilatory depression with loss of ...dyspnea which is called as happy hypoxia. This report describes the background and the clinical issues of happy hypoxia.Methods: The mechanisms to increase ventilation and dyspnea under hypoxia are explained. Further, clinical issues and characteristics in COVID-19 are reviewed.Results: Genetic factors are definitely concerned with chemosensitivity to hypoxia. Further disease factors including COVID-19 infection could influence the attenuation of the chemosensitivity. This can be attributed to either ventilatory depression due to the modulation of metabolic substrate, adenosine in the brain, or autonomic neuropathy including the dysfunction of the carotid body.Conclusions: COVID-19 patients must be carefully treated and/or monitored to avoid hypoxic ventilator depression. The clinical application of aminophylline will be an issue to be considered.
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