We present X-ray timing results of the new black hole candidate MAXI J1535−571 during its 2017 outburst from Hard X-ray Modulation Telescope (Insight-HXMT) observations taken from 2017 September 6 to ...23. Following the definitions given by Belloni, we find that the source exhibits transitions from the low/hard state to the hard intermediate state, and eventually to the soft intermediate state. Quasi-periodic oscillations (QPOs) are found in the intermediate states, which suggest different types of QPOs. With the large effective area of Insight-HXMT at high energies, we are able to present the energy dependence of the QPO amplitude and centroid frequency up to 100 keV, which has rarely been explored by previous satellites. We also find that the phase lag at the type-C QPOs centroid frequency is negative (soft lag) and strongly correlated with the centroid frequency. Assuming a geometrical origin of type-C QPOs, the source is consistent with being a high-inclination system.
Abstract
We report on analysis of observations of the bright transient X-ray pulsar Swift J0243.6+6124 obtained during its 2017-2018 giant outburst with Insight-HXMT, NuSTAR, and Swift observatories. ...We focus on the discovery of a sharp state transition of the timing and spectral properties of the source at super-Eddington accretion rates, which we associate with the transition of the accretion disk to a radiation pressure dominated (RPD) state, the first ever directly observed for magnetized neutron star. This transition occurs at slightly higher luminosity compared to already reported transition of the source from sub- to super-critical accretion regime associate with onset of an accretion column. We argue that this scenario can only be realized for comparatively weakly magnetized neutron star, not dissimilar to other ultra-luminous X-ray pulsars (ULPs), which accrete at similar rates. Further evidence for this conclusion is provided by the non-detection of the transition to the propeller state in quiescence which strongly implies compact magnetosphere and thus rules out magnetar-like fields.
Background
The aim of this study was to investigate the prevalence of epidemiologic and physician‐diagnosed pollen‐induced AR (PiAR) in the grasslands of northern China and to study the impact of the ...intensity and time of pollen exposure on PiAR prevalence.
Methods
A multistage, clustered and proportionately stratified random sampling with a field interviewer‐administered survey study was performed together with skin prick tests (SPT) and measurements of the daily pollen count.
Results
A total of 6043 subjects completed the study, with a proportion of 32.4% epidemiologic AR and 18.5% PiAR. The prevalence was higher in males than females (19.6% vs 17.4%, P = .024), but no difference between the two major residential and ethnic groups (Han and Mongolian) was observed. Subjects from urban areas showed higher prevalence of PiAR than rural areas (23.1% vs 14.0%, P < .001). Most PiAR patients were sensitized to two or more pollens (79.4%) with artemisia, chenopodium, and humulus scandens being the most common pollen types, which were similarly found as the top three sensitizing pollen allergens by SPT. There were significant regional differences in the prevalence of epidemiologic AR (from 18.6% to 52.9%) and PiAR (from 10.5% to 31.4%) among the six areas investigated. PiAR symptoms were positively associated with pollen counts, temperature, and precipitation (P < .05), but negatively with wind speed and pressure P < .05).
Conclusion
Pollen‐induced AR (PiAR) prevalence in the investigated region is extremely high due to high seasonal pollen exposure, which was influenced by local environmental and climate conditions.
High-fat diet (HFD) decreases insulin sensitivity. How high-fat diet causes insulin resistance is largely unknown. Here, we show that lean mice become insulin resistant after being administered ...exosomes isolated from the feces of obese mice fed a HFD or from patients with type II diabetes. HFD altered the lipid composition of exosomes from predominantly phosphatidylethanolamine (PE) in exosomes from lean animals (L-Exo) to phosphatidylcholine (PC) in exosomes from obese animals (H-Exo). Mechanistically, we show that intestinal H-Exo is taken up by macrophages and hepatocytes, leading to inhibition of the insulin signaling pathway. Moreover, exosome-derived PC binds to and activates AhR, leading to inhibition of the expression of genes essential for activation of the insulin signaling pathway, including IRS-2, and its downstream genes PI3K and Akt. Together, our results reveal HFD-induced exosomes as potential contributors to the development of insulin resistance. Intestinal exosomes thus have potential as broad therapeutic targets.
Long-term potentiation (LTP) of excitatory synaptic transmission has long been considered a cellular correlate for learning and memory. Early LTP (less than 1 h) had initially been explained either ...by presynaptic increases in glutamate release or by direct modification of postsynaptic AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) receptor function. Compelling models have more recently proposed that synaptic potentiation can occur by the recruitment of additional postsynaptic AMPA receptors (AMPARs), sourced either from an intracellular reserve pool by exocytosis or from nearby extra-synaptic receptors pre-existing on the neuronal surface. However, the exact mechanism through which synapses can rapidly recruit new AMPARs during early LTP remains unknown. In particular, direct evidence for a pivotal role of AMPAR surface diffusion as a trafficking mechanism in synaptic plasticity is still lacking. Here, using AMPAR immobilization approaches, we show that interfering with AMPAR surface diffusion markedly impairs synaptic potentiation of Schaffer collaterals and commissural inputs to the CA1 area of the mouse hippocampus in cultured slices, acute slices and in vivo. Our data also identify distinct contributions of various AMPAR trafficking routes to the temporal profile of synaptic potentiation. In addition, AMPAR immobilization in vivo in the dorsal hippocampus inhibited fear conditioning, indicating that AMPAR diffusion is important for the early phase of contextual learning. Therefore, our results provide a direct demonstration that the recruitment of new receptors to synapses by surface diffusion is a critical mechanism for the expression of LTP and hippocampal learning. Since AMPAR surface diffusion is dictated by weak Brownian forces that are readily perturbed by protein-protein interactions, we anticipate that this fundamental trafficking mechanism will be a key target for modulating synaptic potentiation and learning.
Objective
To assess whether vaginal secretions and breast milk of women with coronavirus disease 2019 (COVID‐19) contain severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2).
Design
Single ...centre cohort study.
Setting
Renmin Hospital of Wuhan University, Wuhan, Hubei province, China.
Population
We studied 13 SARS‐CoV‐2‐infected pregnant women diagnosed between 31 January and 9 March 2020.
Methods
We collected clinical data, vaginal secretions, stool specimens and breast milk from SARS‐CoV‐2‐infected women during different stages of pregnancy and collected neonatal throat and anal swabs.
Main outcomes and measures
We assessed viral presence in different biosamples.
Results
Of the 13 women with COVID‐19, five were in their first trimester, three in their second trimester and five in their third trimester. Of the five women in their third trimester who gave birth, all delivered live newborns. Among these five deliveries, the primary adverse perinatal outcomes included premature delivery (n = 2) and neonatal pneumonia (n = 2). One of nine stool samples was positive; all 13 vaginal secretion samples, and five throat swabs and four anal swabs collected from neonates, were negative for the novel coronavirus. However, one of three samples of breast milk was positive by viral nucleic acid testing.
Conclusions
In this case series of 13 pregnant women with COVID‐19, we observed negative viral test results in vaginal secretion specimens, suggesting that a vaginal delivery may be a safe delivery option. However, additional research is urgently needed to examine breast milk and the potential risk for viral contamination.
Tweetable
New evidence for the safety of vaginal delivery and breastfeeding in pregnant women infected with SARS‐CoV‐2, positive viral result in a breast‐milk sample.
New evidence for the safety of vaginal delivery and breastfeeding in pregnant women infected with SARS‐CoV‐2, positive viral result in a breast‐milk sample.
Diabet. Med. 28, 652–657 (2011)
Aims To investigate the trend in the prevalence of gestational diabetes mellitus during 1999–2008 in women living in urban Tianjin, China.
Methods A universal ...screening for gestational diabetes mellitus has become an integral part of the antenatal care in Tianjin, China from 1998. A total of 105 473 pregnant women living in the six urban districts of Tianjin, China, participated in the gestational diabetes mellitus screening programme between December 1998 and December 2008. The screening test consisted of a 50‐g 1‐h glucose test. Women who had a glucose reading ≥ 7.8 mmol/l at the initial screening were invited to undergo the standard 2‐h oral glucose tolerance test with a 75‐g glucose load. Gestational diabetes mellitus was confirmed using the World Health Organization’s diagnostic criteria.
Results The adjusted prevalence of gestational diabetes mellitus increased by 2.8 times during 1999–2008, from 2.4 to 6.8% (P < 0.0001 for linear trend). In 2008, the age‐specific prevalence of gestational diabetes mellitus was the highest among women aged 30–34 years (11.3%) and lowest among women aged 25 and under (1.2%). In women aged 35 years and more, the prevalence was 5.3%.
Conclusions The prevalence of gestational diabetes mellitus has markedly been increasing in a universally screened urban Chinese female population and has become an important public health problem in China.
Complex-valued neural networks have many advantages over their real-valued counterparts. Conventional digital electronic computing platforms are incapable of executing truly complex-valued ...representations and operations. In contrast, optical computing platforms that encode information in both phase and magnitude can execute complex arithmetic by optical interference, offering significantly enhanced computational speed and energy efficiency. However, to date, most demonstrations of optical neural networks still only utilize conventional real-valued frameworks that are designed for digital computers, forfeiting many of the advantages of optical computing such as efficient complex-valued operations. In this article, we highlight an optical neural chip (ONC) that implements truly complex-valued neural networks. We benchmark the performance of our complex-valued ONC in four settings: simple Boolean tasks, species classification of an Iris dataset, classifying nonlinear datasets (Circle and Spiral), and handwriting recognition. Strong learning capabilities (i.e., high accuracy, fast convergence and the capability to construct nonlinear decision boundaries) are achieved by our complex-valued ONC compared to its real-valued counterpart.
The quantum anomalous Hall (QAH) effect combines topology and magnetism to produce precisely quantized Hall resistance at zero magnetic field. We report the observation of a QAH effect in twisted ...bilayer graphene aligned to hexagonal boron nitride. The effect is driven by intrinsic strong interactions, which polarize the electrons into a single spin- and valley-resolved moiré miniband with Chern number
= 1. In contrast to magnetically doped systems, the measured transport energy gap is larger than the Curie temperature for magnetic ordering, and quantization to within 0.1% of the von Klitzing constant persists to temperatures of several kelvin at zero magnetic field. Electrical currents as small as 1 nanoampere controllably switch the magnetic order between states of opposite polarization, forming an electrically rewritable magnetic memory.
Aim
Gastroparesis is a common non‐motor system symptom of Parkinson's disease (PD). However, the mechanism responsible for the gastric motor abnormality is not clear. We previously reported on the ...impaired gastric motility in 6‐hydroxydopamine (6‐OHDA) rats, which were treated with a bilateral microinjection of 6‐OHDA in the substantia nigra (SN). We hypothesize that the enhanced dopamine system and reduced acetylcholine (Ach) in gastric tissues might contribute to the delayed gastric emptying observed in PD.
Methods
A strain gauge force transducer, digital X‐ray imaging system, Western blot, immunofluorescence and Radio Immunoassay were used in this study.
Results
Dopaminergic neurones in the SN were greatly reduced following the bilateral microinjection of 6‐OHDA. 6‐OHDA rats exhibited impaired gastric motility and delayed gastric emptying, accompanied by increased dopamine content and the overexpression of D2 receptors in the stomach. The administration of the D2 receptor antagonist domperidone relieved gastric dysmotility in 6‐OHDA rats, but the D1 receptor antagonist SCH23390 failed to do so. Subdiaphragmatic vagotomy prevented the increase in the gastric dopamine content and D2 receptor expression and improved gastric dysmotility in 6‐OHDA rats.
Conclusion
Dopaminergic deficiency in the SN results in impaired gastric motility, possibly as a result of the enhanced activity of dopamine system and reduced Ach in gastric tissue. The vagus nerve plays an important role in peripheral gastric motility disorder.
PDF
