Genomic imprinting defect in Zfp57 mutant iPS cell lines

AbstractZFP57 maintains genomic imprinting in mouse embryos and ES cells. To test its roles during iPS reprogramming, we derived iPS clones by utilizing retroviral infection to express reprogramming factors in mouse MEF cells. After analyzing four imprinted regions, we found that parentally derived DNA methylation imprint was largely maintained in the iPS clones with Zfp57 but missing in those without maternal or zygotic Zfp57. Intriguingly, DNA methylation imprint was lost at the Peg1 and Peg3 but retained at the Snrpn and Dlk1-Dio3 imprinted regions in the iPS clones without zygotic Zfp57. This finding will be pursued in future studies

Method and experimental study of 2-D NMR logging

Two-dimension (2D) NMR measurements have been performed to provide more information for qualitative identification and quantitative evaluation of the reservoir-fluids both in numerical simulation and in laboratory experiments. The data acquired with variable echo spacing and waiting time was inverted by multi-exponential inversion method. We use these 2D inversion results to identify fluid types and calculate fluid-saturation. We also detect the distribution of internal field gradients of core samples which contain paramagnetic minerals

A significant reduction in hepatitis B virus infection among the children of Shandong Province, China: the effect of 15 years of universal infant hepatitis B vaccination

AbstractObjectiveTo evaluate the effect of the universal infant hepatitis B vaccination program on hepatitis B infection in China.MethodsIn 2006, a survey was conducted in Shandong Province, China, among children aged 1–14 years, 15 years after the introduction of universal infant hepatitis B vaccination. The subjects were selected by stratified, multi-stage sampling. Vaccination history was obtained by immunization certificate (when available) or parent recall. Hepatitis B surface antigen (HBsAg) and antibodies to HBsAg (anti-HBs) and core antigen (anti-HBc) were detected by ELISA. Hepatitis B infection was defined as the presence of HBsAg and/or anti-HBc. The prevalence rates of HBsAg, anti-HBs and hepatitis B infection obtained in this survey were compared with the results of a survey conducted in 1992 (prior to universal vaccination).ResultsA total of 3738 children aged 1–14 years were included in the final analysis. A vaccination coverage rate of 93% was achieved in 2006. The prevalence rates of HBsAg and hepatitis B infection decreased from 8% and 46% in the 1992 survey to 1% and 4%, respectively, in the 2006 survey.ConclusionsUniversal hepatitis B vaccination in infants can result in a 90.47% reduction in hepatitis B infection in children aged 1–14 years

Comprehensive Experimental Study on the Gas Breakthrough Pressure and Its Implication for the Reservoir Performance

AbstractIt is challenging to interpret the gas breakthrough mechanisms, controlling factors, and its relationships with the reservoir parameters for unconventional reservoirs such as the gas shale, due to the accumulation characteristics of source-reservoir integration. Take the typical marine shale gas of the B field for example, we use the step-by-step (SBS) test to measure the gas breakthrough pressure of the water saturated shales, and investigate the influential factors such as the pore size distribution, mineral composition, and organic geochemical properties. Moreover, the implication of the gas breakthrough capability for the reservoir quality such as the porosity, permeability, the gas content, and the gas occurrence state are addressed. Based on our work, it is observed that the gas breakthrough capability in shale is influenced by many factors. Generally, the gas breakthrough pressure is positively with the amount of ductile minerals such as the clay and the plagioclase, but negatively with the amount of brittle minerals such as the quartz. In addition, the gas breakthrough pressure is decreased with the increase of the pore radius and the specific surface areas. What is more, the influences of geochemical properties on the gas breakthrough capability should not be neglected. Due to the development of organic pores in the kerogen, the gas breakthrough pressure is found to decrease with the increase of the total organic carbon content (TOC) and the residual carbon content (RC). The breakthrough pressure can be used as the significant parameter to indicate the reservoir quality of the shale gas. It is shown that the breakthrough pressure is inversely with the porosity, permeability, the total gas content, and the adsorbed gas content. It is practical and meaningful to measure and estimate the breakthrough pressure for the formation evaluation in shale gas reservoirs

Tailoring magnetic behavior of CoFeMnNiX (X = Al, Cr, Ga, and Sn) high entropy alloys by metal doping

Magnetic materials with excellent performances are desired for functional applications. Based on the high-entropy effect, a system of CoFeMnNiX (X = Al, Cr, Ga, and Sn) magnetic alloys are designed and investigated. The dramatic change in phase structures from face-centered-cubic (FCC) to ordered body-centered-cubic (BCC) phases, caused by adding Al, Ga, and Sn in CoFeMnNiX alloys, originates from the potent short-range chemical order in the liquid state predicted by ab initio molecular dynamics (AIMD) simulations. This phase transition leads to the significant enhancement of the saturation magnetization (Ms), e.g., the CoFeMnNiAl alloy has Ms of 147.86 Am2/kg. First-principles density functional theory (DFT) calculations on the electronic and magnetic structures reveal that the anti-ferromagnetism of Mn atoms in CoFeMnNi is suppressed especially in the CoFeMnNiAl HEA because Al changes the Fermi level and itinerant electron-spin coupling that lead to ferromagnetism

Chemical composition and source apportionment of PM _2.5 in urban areas of Xiangtan, central south China

Xiangtan, South China, is characterized by year-round high relative humidity and very low wind speeds. To assess levels of PM2.5, daily samples were collected from 2016 to 2017 at two urban sites. The mass concentrations of PM2.5 were in the range of 30⁻217 µg/m3, with the highest concentrations in winter and the lowest in spring. Major water-soluble ions (WSIIs) and total carbon (TC) accounted for 58⁻59% and 21⁻24% of the PM2.5 mass, respectively. Secondary inorganic ions (SO42−, NO3−, and NH4+) dominated the WSIIs and accounted for 73% and 74% at the two sites. The concentrations of K, Fe, Al, Sb, Ca, Zn, Mg, Pb, Ba, As, and Mn in the PM2.5 at the two sites were higher than 40 ng/m3, and decreased in the order of winter > autumn > spring. Enrichment factor analysis indicates that Co, Cu, Zn, As, Se, Cd, Sb, Tl, and Pb mainly originates from anthropogenic sources. Source apportionment analysis showed that secondary inorganic aerosols, vehicle exhaust, coal combustion and secondary aerosols, fugitive dust, industrial emissions, steel industry are the major sources of PM2.5, contributing 25⁻27%, 21⁻22%, 19⁻21%, 16⁻18%, 6⁻9%, and 8⁻9% to PM2.5 mass

Radiation-induced brain structural and functional abnormalities in presymptomatic phase and outcome prediction: Radiation-Induced Brain Abnormalities

Radiation therapy, a major method of treatment for brain cancer, may cause severe brain injuries after many years. We used a rare and unique cohort of nasopharyngeal carcinoma patients with normal-appearing brains to study possible early irradiation injury in its presymptomatic phase before severe, irreversible necrosis happens. The aim is to detect any structural or functional imaging biomarker that is sensitive to early irradiation injury, and to understand the recovery and progression of irradiation injury that can shed light on outcome prediction for early clinical intervention. We found an acute increase in local brain activity that is followed by extensive reductions in such activity in the temporal lobe and significant loss of functional connectivity in a distributed, large-scale, high-level cognitive function-related brain network. Intriguingly, these radiosensitive functional alterations were found to be fully or partially recoverable. In contrast, progressive late disruptions to the integrity of the related far-end white matter structure began to be significant after one year. Importantly, early increased local brain functional activity was predictive of severe later temporal lobe necrosis. Based on these findings, we proposed a dynamic, multifactorial model for radiation injury and another preventive model for timely clinical intervention. Hum Brain Mapp 39:407-427, 2018. © 2017 Wiley Periodicals, Inc

A chiral hemiporphyrazine derivative

The synthesis of an optically active hemiporphyrazine with chiral binaphthyl substituents (1) is reported, providing the first example of the incorporation of an intrinsically chiral moiety into the macrocyclic core of a hemiporphyrazine analogue. A negative circular dichroism (CD) signal is observed in the 325–450 nm region of the CD spectrum of (S,S)-1, while mainly positive bands are observed in the 220–325 nm region. Mirror symmetry is observed across the entire wavelength range of the CD spectra of (R,R)-1 and (S,S)-1. An irreversible one-electron oxidation wave with an onset potential at 1.07 V is observed by cyclic voltammetry, along with a reversible one-electron reduction wave at −0.85 V. Density functional calculations reproduce the experimentally observed data and trends, and provide further insight into the nature of the electronic transitions