Tuning the band gap and magnetic properties of BN sheets impregnated with graphene flakes

The BN sheet is a nonmagnetic wide-band-gap semiconductor. Using density functional theory, we show that these properties can be fundamentally altered by embedding graphene flakes. Not only do graphene flakes preserve the two-dimensional (2D) planar structure of the BN sheet, but by controlling their shape and size, unexpected electronic and magnetic properties also emerge. The electronic band structure can be tuned from a direct gap to an indirect gap, the energy gap can be further modulated by changing the bonding patterns, and both hole injecting or electron injecting can be achieved by tailoring the triangular embedding pattern. Furthermore, the Lieb theorem still holds, and the embedded triangular graphene flakes become ferromagnetic with full spin polarizations of the introduced electrons or holes, opening the door to their use as spin filters. The study sheds new light on hybrid single-atomic-layer engineering for unprecedented applications of 2D nanomaterials

Lead bioaccessibility in 12 contaminated soils from China: correlation to lead relative bioavailability and lead in different fractions

This study investigated the relationship between Pb relative bioavailability (RBA) and bioaccessibility, and their relationships with Pb in different pools in soils. Twelve Pb-contaminated soils representing different contamination sources from China were analyzed for Pb bioaccessibility using four in vitro methods (UBM, SBRC, IVG, and PBET), Pb-RBA using a mouse blood model, and Pb fractionation using sequential extraction. Lead bioaccessibility in the gastric phase (GP) and Pb-RBA was generally lower in mining soils (0.46–29% and 7.0–26%) than smelting (19–92% and 31–84%) and farming soils (13–99% and 51–61%), with more Pb in the residual fraction in mining soils. Lead bioaccessibility varied with assays, with SBRC (3.0–99%) producing significantly higher bioaccessible Pb than other assays (0.46–84%) in the gastric phase. However, Pb bioaccessibility in the intestinal phase (IP) of all assays sharply decreased to 0.01–20% possibly due to Pb sorption to solid phase at higher pH. Lead bioaccessibility by UBM-GP assay was best correlated with Pb-RBA (r2 = 0.67), followed by IVG–GP (r2 = 0.55). Among different Pb fractions, strong correlation was found between Pb bioaccessibility/Pb-RBA and the sum of exchangeable and carbonate fractions. Our study suggested that UBM-GP assay has potential to determine Pb bioaccessibility in contaminated soils in China

Brain transplantation of genetically corrected Sanfilippo type B neural stem cells induces partial cross-correction of the disease

Sanfilippo syndrome type B (mucopolysaccharidosis type IIIB) is a recessive genetic disorder that severely affects the brain due to a deficiency in the enzyme α

Estimation of divergence times for major lineages of galliform birds: Evidence from complete mitochondrial genome sequences

Determining an absolute timescale for avian evolutionary history has been recently challenged by the relaxed molecular clock methods, that rates of molecular evolution can vary significantly among organisms. In this study, we used relaxed molecular clocks to date the divergence of major lineages of Galliformes based on complete mitochondrial genomes. A nucleotide dataset of 13 concatenated protein-coding genes from 22 species of Galliformes was used to investigate the evolutionary divergences within the group. Using Gallus bravardi, Schaubortyx and Gallinuloides fossils ascalibration points, divergence times analyses were performed with four relaxed molecular clock methods as follows: (1) Bayesian method of Multidivtime; (2) Bayesian Markov chain Monte Carlo (MCMC) analysis of the Bayesian evolutionary analysis by sampling trees (BEAST); (3) local rate minimum deformation method (LRMD) of TREEFINDER; and (4) nonparametric rate smoothing (NPRS) of TREEFINDER. The various relaxed clock methods all indicated that (1) Megapodiidae originated in theLate Cretaceous; (2) Numididae, Phasianidae, Arborophilinae and Coturnicinae originated in the Eocene of Palaeogene; (3) Pavoninae and Gallininae originated at the Eocene-Oligocene boundary; (4) Phasianinae and Meleagridinae originated in the Oligocene; (5) divergence times estimation among most genera of Phasianidae were much older than those of the previous studies. Our results might provide a more likely time scale for evolutionary history of the galliform birds

Enzyme Replacement Therapy for Mucopolysaccharidosis IIID using Recombinant Human α-N-Acetylglucosamine-6-Sulfatase in Neonatal Mice

There is currently no cure or effective treatment available for mucopolysaccharidosis type IIID (MPS IIID, Sanfilippo syndrome type D), a lysosomal storage disorder (LSD) caused by the deficiency of α-N-acetylglucosamine-6-sulfatase (GNS). The clinical symptoms of MPS IIID, like other subtypes of Sanfilippo syndrome, are largely localized to the central nervous system (CNS), and any treatments aiming to ameliorate or reverse the catastrophic and fatal neurologic decline caused by this disease need to be delivered across the blood–brain barrier. Here, we report a proof-of-concept enzyme replacement therapy (ERT) for MPS IIID using recombinant human α-N-acetylglucosamine-6-sulfatase (rhGNS) via intracerebroventricular (ICV) delivery in a neonatal MPS IIID mouse model. We overexpressed and purified rhGNS from CHO cells with a specific activity of 3.9 × 10⁴ units/mg protein and a maximal enzymatic activity at lysosomal pH (pH 5.6), which was stable for over one month at 4 °C in artificial cerebrospinal fluid (CSF). We demonstrated that rhGNS was taken up by MPS IIID patient fibroblasts via the mannose 6-phosphate (M6P) receptor and reduced intracellular glycosaminoglycans to normal levels. The delivery of 5 μg of rhGNS into the lateral cerebral ventricle of neonatal MPS IIID mice resulted in normalization of the enzymatic activity in brain tissues; rhGNS was found to be enriched in lysosomes in MPS IIID-treated mice relative to the control. Furthermore, a single dose of rhGNS was able to reduce the accumulated heparan sulfate and β-hexosaminidase. Our results demonstrate that rhGNS delivered into CSF is a potential therapeutic option for MPS IIID that is worthy of further development

Public Health and Air Pollution in Asia (PAPA): A Multicity Study of Short-Term Effects of Air Pollution on Mortality

Background and Objectives: Although the deleterious effects of air pollution from fossil fuel combustion have been demonstrated in many Western nations, fewer studies have been conducted in Asia. The Public Health and Air Pollution in Asia (PAPA) project assessed the effects of short-term exposure to air pollution on daily mortality in Bangkok, Thailand, and in three cities in China: Hong Kong, Shanghai, and Wuhan. Methods: Poisson regression models incorporating natural spline smoothing functions were used to adjust for seasonality and other time-varying covariates that might confound the association between air pollution and mortality. Effect estimates were determined for each city and then for the cities combined using a random effects method. Results: In individual cities, associations were detected between most of the pollutants [nitrogen dioxide, sulfur dioxide, particulate matter ≤ 10 μm in aerodynamic diameter (PM 10), and ozone] and most health outcomes under study (i.e., all natural-cause, cardiovascular, and respiratory mortality). The city-combined effects of the four pollutants tended to be equal or greater than those identified in studies conducted in Western industrial nations. In addition, residents of Asian cities are likely to have higher exposures to air pollution than those in Western industrial nations because they spend more time outdoors and less time in air conditioning. Conclusions: Although the social and environmental conditions may be quite different, it is reasonable apply estimates derived from previous health effect of air pollution studies in the West to Asia.published_or_final_versio