Substantial biogenic secondary organic aerosol (BSOA) formation was investigated in a coniferous forest mountain region in Whistler, British Columbia. A largely biogenic aerosol growth episode was ...observed, providing a unique opportunity to investigate BSOA formation chemistry in a forested environment with limited influence from anthropogenic emissions. Positive matrix factorization of aerosol mass spectrometry (AMS) measurement identified two types of BSOA (BSOA-1 and BSOA-2), which were primarily generated by gas-phase oxidation of monoterpenes and perhaps sesquiterpenes. The temporal variations of BSOA-1 and BSOA-2 can be explained by gas–particle partitioning in response to ambient temperature and the relative importance of different oxidation mechanisms between day and night. While BSOA-1 arises from gas-phase ozonolysis and nitrate radical chemistry at night, BSOA-2 is likely less volatile than BSOA-1 and consists of products formed via gas-phase oxidation by OH radical and ozone during the day. Organic nitrates produced through nitrate radical chemistry can account for 22–33 % of BSOA-1 mass at night. The mass spectra of BSOA-1 and BSOA-2 have higher values of the mass fraction of m/z 91 (f91) compared to the background organic aerosol. Using f91 to evaluate BSOA formation pathways in this unpolluted, forested region, heterogeneous oxidation of BSOA-1 is a minor production pathway of BSOA-2.
A precision measurement by AMS of the antiproton flux and the antiproton-to-proton flux ratio in primary cosmic rays in the absolute rigidity range from 1 to 450 GV is presented based on 3.49×10^{5} ...antiproton events and 2.42×10^{9} proton events. The fluxes and flux ratios of charged elementary particles in cosmic rays are also presented. In the absolute rigidity range ∼60 to ∼500 GV, the antiproton pover ¯, proton p, and positron e^{+} fluxes are found to have nearly identical rigidity dependence and the electron e^{-} flux exhibits a different rigidity dependence. Below 60 GV, the (pover ¯/p), (pover ¯/e^{+}), and (p/e^{+}) flux ratios each reaches a maximum. From ∼60 to ∼500 GV, the (pover ¯/p), (pover ¯/e^{+}), and (p/e^{+}) flux ratios show no rigidity dependence. These are new observations of the properties of elementary particles in the cosmos.
New chiral thiazolidine derivatives were synthesized conveniently from natural
l-cysteine and showed good enantioselectivity (up to 90% ee) in the addition of diethylzinc to aldehydes. The catalytic ...efficiency of the thiazolidine derivatives is influenced by the different structures of the thiazolidine rings and the bulkiness of R moiety in the ester groups.
Gastric antral vascular ectasia (GAVE) is an uncommon but important cause of chronic gastrointestinal bleeding. It is often associated with systemic diseases such as autoimmune diseases, liver ...cirrhosis, chronic renal insufficiency and cardiovascular disease. The etiology of GAVE has not been fully explored and remains controversial. Diagnosis is mainly based on endoscopic presentation with flat or raised erythematous stripes radiating from the pylorus to the antrum and resembles a watermelon. Clinical presentation may range from iron-deficiency anemia secondary to occult blood loss, melena to hematemesis. In past decades, many therapeutic modalities including medical, endoscopic and surgical intervention have been introduced for GAVE treatment with variable efficacy. Herein, we review the efficacy and safety of these treatment options for GAVE.
A new tetraazamacrocyclic ligand (L) with four neutral 2-cyanoethyl pendent groups, and its divalent transition-metal complexes Co(L)(NO
3)NO
3·H
2O (
1), Ni(L)(NO
3)NO
3·3H
2O (
2) and Cu(L)(H
...2O)(NO
3)
2 (
3) have been synthesized. The crystal structures of
1 and
3 have been determined by X-ray analysis. In complex
1 the cobalt atom is coordinated by four nitrogen atoms and two oxygen atoms of a nitrate anion, which define a distorted octahedron. The other nitrate ion lies in the lattice as a counter ion. Complex
3 is five-coordinated by four nitrogen atoms and an axial aqua ligand, which form a tetragonal pyramid. In complex
3 the two nitrate anions exist as counter ions. Pharmaceutical tests showed that all three metal complexes exhibit antitumor activity against HL-60 and BEL-7404 tumor cell lines in vitro, even at a concentration of 10
−8 mol l
−1. Complex
1 can partially cleave supercoiled pBR 322 DNA to form nicked DNA in aerobic solution, and complex
3 can convert double strand DNA into nicked DNA completely in the presence of MPA. Complex
3 causes perturbation to K562 tumor cell lines in the G
1 phase.
Dayside Pc 1 geomagnetic pulsation bursts have been studied using a three‐station array of induction magnetometers located at high latitudes (geomagnetic latitude (MLAT) of −70° to −81°). The data ...set reveals that when these emissions are continually recorded at Davis (MLAT = −74.5°; L = 14), the low‐latitude cleft, observed by the DMSP F7 satellite, is located at the Davis latitude. Associated magnetic variations in the form of solitary pulses often lead the Pc 1 bursts by 1 to 2 min. These pulses are typically associated with riometer absorption events and consequently the precipitation of fluxes of keV electrons. The Pc 1 bursts are interpreted as resulting from ion cyclotron waves which have propagated to the ionosphere from the equatorial boundary layer region. The associated boundary layer ions, identified by the low‐altitude DMSP F7 satellite, range between 1 and 5 keV in energy. These particles are considered to be the most likely free energy source for the ion cyclotron waves. It is considered that such resonant ions enter the magnetosphere via the cleft and cusp because this enables a prenoon time of occurrence of most of the observations to be explained. Measured time delays of 40 to 120 s between the associated riometer absorption and Pc 1 bursts are consistent with an ion cyclotron wave generation region located in the equatorial magnetosphere.
Highlights • HFS of the macaque hippocampus markedly reduced KA-induced seizure activity. • HFS afforded marked protection against neuronal cell death following KA treatment. • HFS attenuated ...KA-induced changes in apoptosis-related proteins.
Cell-cell communication via ligand-receptor signaling is a fundamental feature of complex organs. Despite this, the global landscape of intercellular signaling in mammalian liver has not been ...elucidated. Here we perform single-cell RNA sequencing on non-parenchymal cells isolated from healthy and NASH mouse livers. Secretome gene analysis revealed a highly connected network of intrahepatic signaling and disruption of vascular signaling in NASH. We uncovered the emergence of NASH-associated macrophages (NAMs), which are marked by high expression of triggering receptors expressed on myeloid cells 2 (Trem2), as a feature of mouse and human NASH that is linked to disease severity and highly responsive to pharmacological and dietary interventions. Finally, hepatic stellate cells (HSCs) serve as a hub of intrahepatic signaling via HSC-derived stellakines and their responsiveness to vasoactive hormones. These results provide unprecedented insights into the landscape of intercellular crosstalk and reprogramming of liver cells in health and disease.
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•Heterogeneity and plasticity of non-parenchymal cells in healthy and NASH liver•Landscape of intrahepatic ligand-receptor signaling at single-cell resolution•Emergence of Trem2+ NASH-associated macrophages (NAMs) in mouse and human NASH•Stellakine secretion and contractile response to vasoactive hormones by HSCs
This work illustrates the heterogeneity of liver non-parenchymal cells (NPCs) and their reprogramming during NASH pathogenesis. Using single-cell RNA-sequencing analysis, the authors mapped the landscape of the intrahepatic ligand-receptor signaling network and revealed two fundamental aspects of HSC biology: stellakine secretion and contractile response to vasoactive hormones. Hepatic vascular dysfunction and emergence of Trem2+ NASH-associated macrophages (NAMs) are two conserved features of mouse and human NASH.
China's electricity generation is mainly dependent on fossil fuel. Promoting electricity conservation in different sectors and regions plays a vital role in reducing China's energy-related CO2 ...emissions and other pollutants. This paper contributes to identify the sectors and economic regions with larger electricity-saving potential and make policy recommendations for promoting electricity conservation. Two indicators, namely TEC (technical elasticity coefficient) and PSC (price sensitivity coefficient), are constructed within an input–output analysis framework to measure the electricity-saving potential. The proposed indicators are applied to analyze the electricity-saving potentials of 20 sectors and 30 provinces in China. We also use EFC (electricity forward correlation coefficient) to examine the relationship between power consumption and electricity-saving potential. Our empirical results show that Mechanical industry, Construction industry and Chemical industry have the largest electricity-saving potential. Meanwhile, the east region of China also shows greater electricity-saving potential. It is suggested that Chinese government adopt pricing regulation and technology innovation policies jointly to promote China's energy conservation. Some important policy implications according to our empirical study are also proposed.
•Two indicators for measuring ESP (electricity-saving potential) are proposed.•The ESPs for 30 provinces and 20 sectors in China are assessed.•Five sectors in China have significant ESPs.•East region of China shows the highest ESP.•China should take pricing regulation and technology innovation policies jointly.
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