Context:
Congenital adrenal hyperplasia (CAH) is an autosomal recessive condition that arises from mutations in CYP21A2 gene, which encodes for the steroidogenic enzyme 21-hydroxylase. To prevent ...genital ambiguity in affected female fetuses, prenatal treatment with dexamethasone must begin on or before gestational week 9. Currently used chorionic villus sampling and amniocentesis provide genetic results at approximately 14 weeks of gestation at the earliest. This means that mothers who want to undergo prenatal dexamethasone treatment will be unnecessarily treating seven of eight fetuses (males and three of four unaffected females), emphasizing the desirability of earlier genetic diagnosis in utero.
Objective:
The objective of the study was to develop a noninvasive method for early prenatal diagnosis of fetuses at risk for CAH.
Patients:
Fourteen families, each with a proband affected by phenotypically classical CAH, were recruited.
Design:
Cell-free fetal DNA was obtained from 3.6 mL of maternal plasma. Using hybridization probes designed to capture a 6-Mb region flanking CYP21A2, targeted massively parallel sequencing (MPS) was performed to analyze genomic DNA samples from parents and proband to determine parental haplotypes. Plasma DNA from pregnant mothers also underwent targeted MPS to deduce fetal inheritance of parental haplotypes.
Results:
In all 14 families, the fetal CAH status was correctly deduced by targeted MPS of DNA in maternal plasma, as early as 5 weeks 6 days of gestation.
Conclusions:
MPS on 3.6 mL plasma from pregnant mothers could potentially provide the diagnosis of CAH, noninvasively, before the ninth week of gestation. Only affected female fetuses will thus be treated. Our strategy represents a generic approach for noninvasive prenatal testing for an array of autosomal recessive disorders.
Summary
Objective: Diabetes mellitus is associated with endothelial dysfunction and oxidative stress (OS). The aim of the present study was to determine whether increased OS and impaired endothelial ...function, are present in early states of diabetes, such as impaired glucose tolerance (IGT) and impaired fasting glucose (IFG).
Methods: Brachial artery flow‐mediated dilatation (FMD) and nitrate‐induced dilatation were measured in 133 subjects with carbohydrate abnormalities (45 IGT, 44 IFG and 44 Type 2 diabetes mellitus) and in 46 subjects with normal glucose tolerance (NGT). Waist circumference, body mass index, blood pressure and fasting lipid profiles were obtained, and glucose and insulin values in response to a 75‐g oral glucose load were also measured. Plasma malondialdehyde (MDA) and superoxide dismutase (SOD) activity were determined.
Results: Patients with diabetes and prediabetes had a higher plasma MDA concentration, but a lower plasma SOD activity than the NGT group (p = 0.006) and SOD activity was positively associated with FMD (p = 0.039). FMD were significantly reduced in the groups of subjects with abnormal carbohydrate metabolism compared with the NGT group (p = 0.035). Among the subjects with diabetes and prediabetes, FMD showed a negative correlation with fasting glucose and/or plasma glucose level at 120 min after oral glucose tolerance test (p = 0.028).
Conclusions: The results showed that endothelial dysfunction and increased OS were present in subjects with IGT and IFG, indicating endothelial damage in these stages.
Scattering of solar radiation by aerosol particles is highly dependent on relative humidity (RH) as hygroscopic particles take up water with increasing RH. To achieve a better understanding of the ...effect of aerosol hygroscopic growth on light scattering properties and radiative forcing, the aerosol scattering coefficients at RH in the range of 40 to ~ 90 % were measured using a humidified nephelometer system in the Yangtze River Delta of China in March 2013. In addition, the aerosol size distribution and chemical composition were measured. During the observation period, the mean and standard deviation (SD) of enhancement factors at RH = 85 % for the scattering coefficient (f(85 %)), backscattering coefficient (fb(85 %)), and hemispheric backscatter fraction (f beta (85 %)) were 1.58 plus or minus 0.12, 1.25 plus or minus 0.07, and 0.79 plus or minus 0.04, respectively, i.e., aerosol scattering coefficient and backscattering coefficient increased by 58 and 25 % as the RH increased from 40 to 85 %. Concurrently, the aerosol hemispheric backscatter fraction decreased by 21 %. The relative amount of organic matter (OM) or inorganics in PM1 was found to be a main factor determining the magnitude of f(RH). The highest values of f(RH) corresponded to the aerosols with a small fraction of OM, and vice versa. The relative amount of NO3- in fine particles was strongly correlated with f(85 %), which suggests that NO3- played a vital role in aerosol hygroscopic growth during this study. The mass fraction of nitrate also had a close relationship to the curvature of the humidograms; higher mass fractions of nitrate were associated with humidograms that had the least curvature. Aerosol hygroscopic growth caused a 47 % increase in the calculated aerosol direct radiative forcing at 85 % RH, compared to the forcing at 40 % RH.
Some gamma-ray bursts (GRBs) have a tera-electron volt (TeV) afterglow, but the early onset of this has not been observed. We report observations with the Large High Altitude Air Shower Observatory ...(LHAASO) of the bright GRB 221009A, which serendipitously occurred within the instrument's field of view. More than 64,000 photons >0.2 TeV were detected within the first 3000 seconds. The TeV flux began several minutes after the GRB trigger and then rose to a peak ~10 seconds later. This was followed by a decay phase, which became more rapid ~650 seconds after the peak. We interpret the emission using a model of a relativistic jet with half-opening angle of ~0.8°. This is consistent with the core of a structured jet and could explain the high isotropic energy of this GRB.
Abstract
Two-dimensional (2D) topological insulators (TIs) are promising platforms for low-dissipation spintronic devices based on the quantum-spin-Hall (QSH) effect, but experimental realization of ...such systems with a large band gap suitable for room-temperature applications has proven difficult. Here, we report the successful growth on bilayer graphene of a quasi-freestanding WSe
2
single layer with the 1
T
′ structure that does not exist in the bulk form of WSe
2
. Using angle-resolved photoemission spectroscopy (ARPES) and scanning tunneling microscopy/spectroscopy (STM/STS), we observe a gap of 129 meV in the 1
T
′ layer and an in-gap edge state located near the layer boundary. The system′s 2D TI characters are confirmed by first-principles calculations. The observed gap diminishes with doping by Rb adsorption, ultimately leading to an insulator–semimetal transition. The discovery of this large-gap 2D TI with a tunable band gap opens up opportunities for developing advanced nanoscale systems and quantum devices.
Organic aerosol (OA) data acquired by the Aerosol Mass Spectrometer (AMS) in 37 field campaigns were deconvolved into hydrocarbon‐like OA (HOA) and several types of oxygenated OA (OOA) components. ...HOA has been linked to primary combustion emissions (mainly from fossil fuel) and other primary sources such as meat cooking. OOA is ubiquitous in various atmospheric environments, on average accounting for 64%, 83% and 95% of the total OA in urban, urban downwind, and rural/remote sites, respectively. A case study analysis of a rural site shows that the OOA concentration is much greater than the advected HOA, indicating that HOA oxidation is not an important source of OOA, and that OOA increases are mainly due to SOA. Most global models lack an explicit representation of SOA which may lead to significant biases in the magnitude, spatial and temporal distributions of OA, and in aerosol hygroscopic properties.
The diffuse Galactic γ-ray emission, mainly produced via interactions between cosmic rays and the interstellar medium and/or radiation field, is a very important probe of the distribution, ...propagation, and interaction of cosmic rays in the Milky Way. In this Letter, we report the measurements of diffuse γ rays from the Galactic plane between 10 TeV and 1 PeV energies, with the square kilometer array of the Large High Altitude Air Shower Observatory (LHAASO). Diffuse emissions from the inner (15°<l<125°, |b|<5°) and outer (125°<l<235°, |b|<5°) Galactic plane are detected with 29.1σ and 12.7σ significance, respectively. The outer Galactic plane diffuse emission is detected for the first time in the very- to ultra-high-energy domain (E>10 TeV). The energy spectrum in the inner Galaxy regions can be described by a power-law function with an index of -2.99±0.04, which is different from the curved spectrum as expected from hadronic interactions between locally measured cosmic rays and the line-of-sight integrated gas content. Furthermore, the measured flux is higher by a factor of ∼3 than the prediction. A similar spectrum with an index of -2.99±0.07 is found in the outer Galaxy region, and the absolute flux for 10≲E≲60 TeV is again higher than the prediction for hadronic cosmic ray interactions. The latitude distributions of the diffuse emission are consistent with the gas distribution, while the longitude distributions show clear deviation from the gas distribution. The LHAASO measurements imply that either additional emission sources exist or cosmic ray intensities have spatial variations.
Sea salt aerosols (SSA) are dominant particles in the Arctic atmosphere and determine the polar radiative balance. SSA react with acidic pollutants that lead to changes in physical and chemical ...properties of their surface, which in turn alter their hygroscopic and optical properties. Transmission electron microscopy with energy-dispersive X-ray spectrometry was used to analyze morphology, composition, size, and mixing state of individual SSA at Ny-Ålesund, Svalbard, in summertime. Individual fresh SSA contained cubic NaCl coated by certain amounts of MgCl2 and CaSO4. Individual partially aged SSA contained irregular NaCl coated by a mixture of NaNO3, Na2SO4, Mg(NO3)2, and MgSO4. The comparison suggests the hydrophilic MgCl2 coating in fresh SSA likely intrigued the heterogeneous reactions at the beginning of SSA and acidic gases. Individual fully aged SSA normally had Na2SO4 cores and an amorphous coating of NaNO3. Elemental mappings of individual SSA particles revealed that as the particles ageing Cl gradually decreased, the C, N, O, and S content increased. 12C- mapping from nanoscale secondary ion mass spectrometry indicates that organic matter increased in the aged SSA compared with the fresh SSA. 12C- line scan further shows that organic matter was mainly concentrated on the aged SSA surface. These new findings indicate that this mixture of organic matter and NaNO3 on particle surfaces likely determines their hygroscopic and optical properties. These abundant SSA as reactive surfaces adsorbing inorganic and organic acidic gases can shorten acidic gas lifetime and influence the possible gaseous reactions in the Arctic atmosphere, which need to be incorporated into atmospheric chemical models in the Arctic troposphere.
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