Emission from field burning of crop residue, a common practice in many parts of the world today, has potential effects on air quality, atmosphere and climate. This study provides a comprehensive size ...and compositional characterization of particulate matter (PM) emission from rice straw (RS) burning using both
in situ experiments (11 spread field burning) and laboratory hood experiments (3 pile and 6 spread burning) that were conducted during 2003-2006 in Thailand. The carbon balance and emission ratio method was used to determine PM emission factors (EF) in the field experiments. The obtained EF varied from field to hood experiments reflecting multiple factors affecting combustion and emission. In the hood experiments, EF were found to be depending on the burning types (spread or pile), moisture content and the combustion efficiency. In addition, in the field experiments, burning rate and EF were also influenced by weather conditions, i.e. wind. Hood pile burning produced significantly higher EF (20
±
8
g
kg
−1 RS) than hood spread burning (4.7
±
2.2
g
kg
−1 RS). The majority of PM emitted from the field burning was PM
2.5 with EF of 5.1
±
0.7
g
m
−2 or 8.3
±
2.7
g
kg
−1 RS burned. The coarse PM fraction (PM
10–2.5) was mainly generated by fire attention activities and was relatively small, hence the resulting EF of PM
10 (9.4
±
3.5
g
kg
−1 RS) was not significantly higher than PM
2.5. PM size distribution was measured across 8 size ranges (from <0.4
μm to >9.0
μm). The largest fractions of PM, EC and OC were associated with PM
1.1. The most significant components in PM
2.5 and PM
10 include OC, water soluble ions and levoglucosan. Relative abundance of some methoxyphenols (e.g., acetylsyringone), PAHs (e.g., fluoranthene and pyrene), organochlorine pesticides and PCBs may also serve as additional signatures for the PM emission. Presence of these toxic compounds in PM of burning smoke increases the potential toxic effects of the emission. For illustration, an estimation of the annual RS field burning in Thailand was made using the obtained
in situ field burning EF and preliminary burning activity data.
Non‐volatile memory cells using Co‐doped BaTiO3 as an active layer exhibit high‐performance unipolar resistive switching characteristics, with a resistance ratio over 104, retention time longer than ...7 × 104 s, endurance over 105 cycles, and switching speed less than 10 ns/70 ns for SET/RESET. Under high electric field and large Joule heating, the easily varied valence of Co ions, the pre‐existing oxygen vacancies with sufficiently high density, and the local itinerant electrons introduced by the Co‐doping all favor the local metal‐insulator phase transition and therein the formation/rupture of conductive filaments, contributing to the stable resistive switching.
The transport of spin information has been studied in various materials, such as metals, semiconductors and graphene. In these materials, spin is transported by the diffusion of conduction electrons. ...Here we study the diffusion and relaxation of spin in a magnetic insulator, where the large bandgap prohibits the motion of electrons. Spin can still be transported, however, through the diffusion of non-equilibrium magnons, the quanta of spin-wave excitations in magnetically ordered materials. Here we show experimentally that these magnons can be excited and detected fully electrically in a linear response, and can transport spin angular momentum through the magnetic insulator yttrium iron garnet (YIG) over distances as large as 40 μm. We identify two transport regimes: the diffusion-limited regime for distances shorter than the magnon spin diffusion length, and the relaxation-limited regime for larger distances. With a model similar to the diffusion-relaxation model for electron spin transport in (semi)conducting materials, we extract the magnon spin diffusion length λ = 9.4 ± 0.6 μm in a thin 200 nm YIG film at room temperature.
The coronavirus disease 2019 (COVID-19) pandemic poses a current world-wide public health threat. However, little is known about its hallmarks compared to other infectious diseases. Here, we report ...the single-cell transcriptional landscape of longitudinally collected peripheral blood mononuclear cells (PBMCs) in both COVID-19- and influenza A virus (IAV)-infected patients. We observed increase of plasma cells in both COVID-19 and IAV patients and XIAP associated factor 1 (XAF1)-, tumor necrosis factor (TNF)-, and FAS-induced T cell apoptosis in COVID-19 patients. Further analyses revealed distinct signaling pathways activated in COVID-19 (STAT1 and IRF3) versus IAV (STAT3 and NFκB) patients and substantial differences in the expression of key factors. These factors include relatively increase of interleukin (IL)6R and IL6ST expression in COVID-19 patients but similarly increased IL-6 concentrations compared to IAV patients, supporting the clinical observations of increased proinflammatory cytokines in COVID-19 patients. Thus, we provide the landscape of PBMCs and unveil distinct immune response pathways in COVID-19 and IAV patients.
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•We generated a single-cell atlas of PBMCs in both COVID-19 and influenza patients•Plasma cells increase significantly in both COVID-19 and influenza patients•COVID-19 is featured with XAF1-, TNF-, and FAS-induced T cell apoptosis•COVID-19 activates distinct pathway (STAT1/IRF3) versus influenza (STAT3/NFκB)
COVID-19 and influenza are both respiratory infections with cytokine release syndrome. Zhu et al. use single-cell RNA sequencing of longitudinally collected PBMCs in both patients to reveal distinct immune response landscapes of the two diseases and identify virus-specific cell composition and immune response pathways.
Thermoelectric properties of a black phosphorus/blue phosphorus van der Waals heterostructure are investigated by using first-principles calculations and Boltzmann transport theory for both electrons ...and phonons. It is found that the heterostructure is both energetically and kinetically stable even at higher temperature. Compared with those of the constituent black and blue phosphorus monolayers, the thermoelectric performance of the heterostructure is significantly enhanced due to sharply decreased thermal conductivity caused by the presence of van der Waals interactions, as well as obviously reduced band gaps and multi-valley structures resulting from type-II band alignment. As a consequence, the room temperature
ZT
value can reach 1.6, which is much higher than those of the components. Furthermore, we obtain
ZT
over 2.0 in a wide temperature range from 400 to 800 K, and a maximum
ZT
of ∼3.2 can be realized at 700 K, which is surprisingly good for systems consisting of light elements only.
Thermoelectric properties of a black phosphorus/blue phosphorus van der Waals heterostructure are investigated by using first-principles calculations and Boltzmann transport theory for both electrons and phonons.
This study was aimed at investigating the role and molecular mechanism of Sam68 in cervical cancer lymph node metastasis.
Sam68 expression profile was detected by quantitative polymerase chain ...reaction, western blotting and immunohistochemical staining. Short hairpin RNA interfering approach was employed to suppress endogenous Sam68 expression in cervical cancer cells to determine its role in metastasis and the possible mechanism.
Sam68 expression in cervical cancer was significantly up-regulated at both messenger RNA and protein levels compared with that in normal cervical tissues. The high expression level of Sam68 and its cytoplasmic localization were significantly associated with risk factors including pelvic lymph node metastasis (P < 0.001), and served as independent prognostic factors for predicting shortening of the overall survival time and disease-free survival time in patients with early-stage cervical cancer. Moreover, down-regulation of Sam68 in cervical cancer cells remarkably inhibited cellular motility and invasion. In addition, down-regulation of Sam68 reversed epithelial–mesenchymal transition through inhibiting the Akt/ GSK-3β/Snail pathway.
This study demonstrated that Sam68 could induce cervical cancer lymph node metastasis through regulating epithelial-mesenchymal transition, and Sam68 expression profile possessed the potential to serve as predictors of pelvic lymph node metastasis in cervical cancer patients.
We report accelerated particles observed by Solar Wind Ion Detectors (SWIDs) on Chang'E‐1 spacecraft close to terminator regions of the Moon. As the spacecraft crosses the terminator, a stream of ...ions with energy of ∼200eV/q are detected. As the spacecraft moves to the anti‐subsolar point of the Moon, the energy of these ions increase by 600 ∼ 1500eV. This phenomenon occurs at north/south pole when IMF By component is dominant and negative/positive. It is proposed these particles are scattered solar wind protons, accelerated by the convection electric field of the solar wind and E × B drift in the ambipolar electric field at the flank of the lunar wake. This mechanism allows a new portion of solar wind protons to enter the central lunar wake, and provides a possibility to study the property of proton scattering at the dayside of the Moon.
The formability and mechanical properties of many engineering alloys are intimately related to the formation and growth of twins. Understanding the structure and chemistry of twin boundaries at the ...atomic scale is crucial if we are to properly tailor twins to achieve a new range of desired properties. We report an unusual phenomenon in magnesium alloys that until now was thought unlikely: the equilibrium segregation of solute atoms into patterns within fully coherent terraces of deformation twin boundaries. This ordered segregation provides a pinning effect for twin boundaries, leading to a concomitant but unusual situation in which annealing strengthens rather than weakens these alloys. The findings point to a platform for engineering nano-twinned structures through solute atoms. This may lead to new alloy compositions and thermomechanical processes.
In this study, researchers describe the clinical characteristics of coronavirus disease 2019 in a selected cohort of 1099 patients with laboratory-confirmed disease throughout mainland China during ...the first 2 months of the current outbreak.
Blood-brain barrier (BBB) disruption occurs early enough to be within the thrombolytic time window, and this early ischemic BBB damage is closely associated with hemorrhagic transformation and thus ...emerging as a promising target for reducing the hemorrhagic complications of thrombolytic stroke therapy. However, the mechanisms underlying early ischemic BBB damage remain poorly understood. Here, we investigated the early molecular events of ischemic BBB damage using in vitro oxygen-glucose deprivation (OGD) and in vivo rat middle cerebral artery occlusion (MCAO) models. Exposure of bEND3 monolayer to OGD for 2 h significantly increased its permeability to FITC-labeled dextran and promoted the secretion of metalloproteinase-2 and -9 (MMP-2/9) and cytosolic translocation of caveolin-1 (Cav-1). This same OGD treatment also led to rapid degradation of tight junction protein occludin and dissociation of claudin-5 from the cytoskeleton, which contributed to OGD-induced endothelial barrier disruption. Using selective MMP-2/9 inhibitor SB-3CT (2-(4-phenoxyphenyl)sulfonylmethyl-thiirane) or their neutralizing antibodies or Cav-1 siRNA, we found that MMP-2 was the major enzyme mediating OGD-induced occludin degradation, while Cav-1 was responsible for claudin-5 redistribution. The interaction between Cav-1 and claudin-5 was further confirmed by coimmunoprecipitation. Consistent with these in vitro findings, we observed fluorescence tracer extravasation, increased gelatinolytic activity, and elevated interstitial MMP-2 levels in ischemic subcortical tissue after 2 h MCAO. Moreover, occludin protein loss and claudin-5 redistribution were detected in ischemic cerebromicrovessels. These data indicate that cerebral ischemia initiates two rapid parallel processes, MMP-2-mediated occludin degradation and Cav-1-mediated claudin-5 redistribution, to cause BBB disruption at early stroke stages relevant to acute thrombolysis.
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