79 research outputs found
Tropheryma whipplei-induced plastic bronchitis in children: a case report
This article reports a case of a 7-year-old child with severe pneumonia whose chest CT showed pulmonary consolidation, and bronchoscopy revealed plastic bronchitis. The metagenomic Next-Generation Sequencing (NGS) of the pulmonary lavage fluid suggested the infection of Tropheryma whipplei (T whipplei). The patient was treated with bronchial lavage to remove sputum plugs, intravenous azithromycin, and piperacillin-tazobactam and was discharged after eight days of hospitalization without any recurrence during follow-up. This article aims to raise clinical awareness of T whipplei infection and suggests that NGS for rare pathogens should be performed early for unexplained plastic bronchitis
H5N1 Influenza a Virus Replicates Productively in Pancreatic Cells and Induces Apoptosis and Pro-Inflammatory Cytokine Response
The inflammatory response and apoptosis have been proved to have a crucial role in the pathogenesis of the influenza A virus (IAV). Previous studies indicated that while IAV commonly causes pancreatitis and pancreatic damage in naturally and experimentally infected animals, the molecular mechanisms of the pathogenesis of IAV infection are less reported. In the present study, we showed for the first time that both avian-like (α-2,3-linked) and human-like (α-2,6-linked) sialic acid (SA) receptors were expressed by the mouse pancreatic cancer cell line PAN02 and the human pancreatic cancer cell line PANC-1. Using growth kinetics experiments, we also showed that PAN02 and PANC-1 cells supported the productive replication of the H5N1 highly pathogenic avian influenza while exhibited the limited replication of IAV subtypes H1N1 and H7N2 in vitro. The in vivo infection of H5N1 in pancreatic cells was confirmed by the histopathological and immunohistochemical staining of pancreas tissue from mice. Other than H1N1 and H7N2, severe damage and extensive positive signals were observed in pancreas of H5N1 infected mice. All three virus subtypes induced apoptosis but also triggered the infected PAN02 and PANC-1 cells to release pro-inflammatory cytokines and chemokines including interferon (IFN)-α, IFN-β, IFN-γ, chemokine (C-C motif) ligand 2 (CCL2), tumor necrosis factor (TNF)-α, and interleukin (IL)-6. Notably, the subtypes of H5N1 could significantly upregulate these cytokines and chemokines in both two cells when compared with H1N1 and H7N2. The present data provide further understanding of the pathogenesis of H5N1 IAV in pancreatic cells derived from humans and mammals and may also benefit the development of new treatment against H5N1 influenza virus infection
Experimental evidence for Berry curvature multipoles in antiferromagnets
Berry curvature multipoles appearing in topological quantum materials have
recently attracted much attention. Their presence can manifest in novel
phenomena, such as nonlinear anomalous Hall effects (NLAHE). The notion of
Berry curvature multipoles extends our understanding of Berry curvature effects
on the material properties. Hence, research on this subject is of fundamental
importance and may also enable future applications in energy harvesting and
high-frequency technology. It was shown that a Berry curvature dipole can give
rise to a 2nd order NLAHE in materials of low crystalline symmetry. Here, we
demonstrate a fundamentally new mechanism for Berry curvature multipoles in
antiferromagnets that are supported by the underlying magnetic symmetries.
Carrying out electric transport measurements on the kagome antiferromagnet
FeSn, we observe a 3rd order NLAHE, which appears as a transverse voltage
response at the 3rd harmonic frequency when a longitudinal a.c. current drive
is applied. Interestingly, this NLAHE is strongest at and above room
temperature. We combine these measurements with a scaling law analysis, a
symmetry analysis, model calculations, first-principle calculations, and
magnetic Monte-Carlo simulations to show that the observed NLAHE is induced by
a Berry curvature quadrupole appearing in the spin-canted state of FeSn. At a
practical level, our study establishes NLAHE as a sensitive probe of
antiferromagnetic phase transitions in other materials, such as moir\'e
superlattices, two-dimensional van der Waal magnets, and quantum spin liquid
candidates, that remain poorly understood to date. More broadly, Berry
curvature multipole effects are predicted to exist for 90 magnetic point
groups. Hence, our work opens a new research area to study a variety of
topological magnetic materials through nonlinear measurement protocols
Free fatty acid hydrolyzed with lipases and their effects on enzyme-modified cheese flavor
peer reviewed: This study investigated the effects of five lipases on enzyme-modified cheese (EMC) flavor development. Results showed that
lipase 30SD contained high hydrolytic activity for short, medium, and long-chain fatty acids within 24 h incubation time, and the highest
content of them among different times could reach 47.24, 475.90, 1 563.92 mg/100 g fat, respectively. Lipase DF15 and MER showed
moderate capacity to hydrolyze volatile fatty acids, while lipase F3G had a stronger ability to produce long-chain fatty acids. Twenty-seven
new volatiles were formed during lipolysis, most of them were acids and esters. Principal component analysis results showed that EMC
produced by lipase 30SD for 18 h was similar to the commercial product with a pungent, rancid, and cheddar flavor. EMCs produced by
lipase DF15 were significantly distinguished from other products by their high content of ethyl heptanoate, ethyl nonanoate, and ethyl
tridecanoate. The findings might be useful for the researchers who focus on lipolysis or EMC product
Observation of nonrelativistic plaid-like spin splitting in a noncoplanar antiferromagnet
Spatial, momentum and energy separation of electronic spins in condensed
matter systems guides the development of novel devices where spin-polarized
current is generated and manipulated. Recent attention on a set of previously
overlooked symmetry operations in magnetic materials leads to the emergence of
a new type of spin splitting besides the well-studied Zeeman, Rashba and
Dresselhaus effects, enabling giant and momentum dependent spin polarization of
energy bands on selected antiferromagnets independent of relativistic
spin-orbit interaction. Despite the ever-growing theoretical predictions, the
direct spectroscopic proof of such spin splitting is still lacking. Here, we
provide solid spectroscopic and computational evidence for the existence of
such materials. In the noncoplanar antiferromagnet MnTe, the in-plane
components of spin are found to be antisymmetric about the high-symmetry planes
of the Brillouin zone, comprising a plaid-like spin texture in the
antiferromagnetic ground state. Such an unconventional spin pattern, further
found to diminish at the high-temperature paramagnetic state, stems from the
intrinsic antiferromagnetic order instead of the relativistic spin-orbit
coupling. Our finding demonstrates a new type of spin-momentum locking with a
nonrelativistic origin, placing antiferromagnetic spintronics on a firm basis
and paving the way for studying exotic quantum phenomena in related materials.Comment: Version 2, 30 pages, 4 main figures and 8 supporting figure
Atomically resolved electrically active intragrain interfaces in perovskite semiconductors
Deciphering the atomic and electronic structures of interfaces is key to developing state-of-the-art perovskite semiconductors. However, conventional characterization techniques have limited previous studies mainly to grain-boundary interfaces, whereas the intragrain-interface microstructures and their electronic properties have been much less revealed. Herein using scanning transmission electron microscopy, we resolved the atomic-scale structural information on three prototypical intragrain interfaces, unraveling intriguing features clearly different from those from previous observations based on standalone films or nanomaterial samples. These intragrain interfaces include composition boundaries formed by heterogeneous ion distribution, stacking faults resulted from wrongly stacked crystal planes, and symmetrical twinning boundaries. The atomic-scale imaging of these intragrain interfaces enables us to build unequivocal models for the ab initio calculation of electronic properties. Our results suggest that these structure interfaces are generally electronically benign, whereas their dynamic interaction with point defects can still evoke detrimental effects. This work paves the way toward a more complete fundamental understanding of the microscopic structure–property–performance relationship in metal halide perovskites
A heterozygous moth genome provides insights into herbivory and detoxification
How an insect evolves to become a successful herbivore is of profound biological and practical importance. Herbivores are often adapted to feed on a specific group of evolutionarily and biochemically related host plants1, but the genetic and molecular bases for adaptation to plant defense compounds remain poorly understood2. We report the first whole-genome sequence of a basal lepidopteran species, Plutella xylostella, which contains 18,071 protein-coding and 1,412 unique genes with an expansion of gene families associated with perception and the detoxification of plant defense compounds. A recent expansion of retrotransposons near detoxification-related genes and a wider system used in the metabolism of plant defense compounds are shown to also be involved in the development of insecticide resistance. This work shows the genetic and molecular bases for the evolutionary success of this worldwide herbivore and offers wider insights into insect adaptation to plant feeding, as well as opening avenues for more sustainable pest management.Minsheng You … Simon W Baxter … et al
Interest Rate Liberalization and Firm Leverage in China: Effects and Channels
We examine whether and how interest rate liberalization affects firm leverage in China. We find that interest rate liberalization exerts a negative effect on the leverage of firms. Specifically, firms experience a reduction in total leverage during the liberalization period, and firms’ short-term leverage declines more relative to long-term leverage. Mechanism analysis shows that firms with high information asymmetry enjoy more decline in leverage relative to firms with low information asymmetry, and further, liberalization policy enables the reduction in credit transaction costs, which indicates that the behavior of banks actively collecting corporate information is an important channel that interest rate liberalization impacts firm leverage. Finally, in additional tests, we find that the impact is more salient when firms are non-state-owned, and loss making. Compare to operating liabilities, firms experience more reduction in financial liability
- …