Formation of highly oxygenated organic molecules from chlorine-atom-initiated oxidation of alpha-pinene

Highly oxygenated organic molecules (HOMs) from atmospheric oxidation of alpha-pinene can irreversibly condense to particles and contribute to secondary organic aerosol (SOA) formation. Recently, the formation of nitryl chloride (C1NO(2)) from heterogeneous reactions, followed by its subsequent photolysis, is suggested to be an important source of chlorine atoms in many parts of the atmosphere. However, the oxidation of monoterpenes such as alpha-pinene by chlorine atoms has received very little attention, and the ability of this reaction to form HOMs is completely unstudied. Here, chamber experiments were conducted with alpha-pinene and chlorine under low- and high-nitrogen-oxide (NOx, NOx = NO+NO2) conditions. A nitrate-based CI-APi-ToF (chemical ionization-atmospheric pressure interface-time of flight) mass spectrometer was used to measure HOM products. Clear distributions of monomers with 9-10 carbon atoms and dimers with 18-20 carbon atoms were observed under low-NOx conditions. With increased concentration of NOx within the chamber, the formation of dimers was suppressed due to the reactions of peroxy radicals with NO. We estimated the HOM yields from chlorine-initiated oxidation of alpha-pinene under low-NOx conditions to be around 1.8 %, though with a substantial uncertainty range (0.8 %-4 %) due to lack of suitable calibration methods. Corresponding yields at high NOx could not be determined because of concurrent ozonolysis reactions. Our study demonstrates that also the oxidation of alpha-pinene by chlorine atoms and yield low-volatility organic compounds.Peer reviewe

KwaiYiiMath: Technical Report

Recent advancements in large language models (LLMs) have demonstrated remarkable abilities in handling a variety of natural language processing (NLP) downstream tasks, even on mathematical tasks requiring multi-step reasoning. In this report, we introduce the KwaiYiiMath which enhances the mathematical reasoning abilities of KwaiYiiBase1, by applying Supervised Fine-Tuning (SFT) and Reinforced Learning from Human Feedback (RLHF), including on both English and Chinese mathematical tasks. Meanwhile, we also constructed a small-scale Chinese primary school mathematics test set (named KMath), consisting of 188 examples to evaluate the correctness of the problem-solving process generated by the models. Empirical studies demonstrate that KwaiYiiMath can achieve state-of-the-art (SOTA) performance on GSM8k, CMath, and KMath compared with the similar size models, respectively.Comment: technical report. arXiv admin note: text overlap with arXiv:2306.16636 by other author

Particle growth with photochemical age from new particle formation to haze in the winter of Beijing, China

Secondary aerosol formation in the aging process of primary emission is the main reason for haze pollution in eastern China. Pollution evolution with photochemical age was studied for the first time at a comprehensive field observation station during winter in Beijing. The photochemical age was used as an estimate of the time scale attributed to the aging process and was estimated from the ratio of toluene to benzene in this study. A low photochemical age indicates a fresh emission. The photochemical age of air masses during new particle formation (NPF) days was lower than that on haze days. In general, the strongest NPF events, along with a peak of the formation rate of 1.5 nm(J(1.5)) and 3 nmparticles (J(3)), were observed when the photochemical age was between 12 and 24 h while rarely took place with photochemical ages less than 12 h. When photochemical age was larger than 48 h, haze occurred and NPF was suppressed. The sources and sinks of nanoparticles had distinct relation with the photochemical age. Our results show that the condensation sink (CS) showed a valley with photochemical ages ranging from 12 to 24 h, while H2SO4 concentration showed no obvious trend with the photochemical age. The high concentrations of precursor vapours within an air mass lead to persistent nucleation with photochemical age ranging from 12 to 48 h in winter. Coincidently, the fast increase of PM2.5 mass was also observed during this range of photochemical age. Noteworthy, CS increased with the photochemical age on NPF days only, which is the likely reason for the observation that the PM2.5 mass increased faster with photochemical age on NPF days compared with other days. The evolution of particles with the photochemical age provides new insights into understanding how particles originating from NPF transform to haze pollution. (C) 2020 Elsevier B.V. All rights reserved.Peer reviewe

Serum Activity of Platelet-Activating Factor Acetylhydrolase Is a Potential Clinical Marker for Leptospirosis Pulmonary Hemorrhage

Pulmonary hemorrhage has been recognized as a major, often lethal, manifestation of severe leptospirosis albeit the pathogenesis remains unclear. The Leptospira interrogans virulent serogroup Icterohaemorrhagiae serovar Lai encodes a protein (LA2144), which exhibited the platelet-activating factor acetylhydrolase (PAF-AH) activity in vitro similar to that of human serum with respect to its substrate affinity and specificity and thus designated L-PAF-AH. On the other hand, the primary amino acid sequence of L-PAF-AH is homologous to the α1-subunit of the bovine brain PAF-AH isoform I. The L-PAF-AH was proven to be an intracellular protein, which was encoded unanimously and expressed similarly in either pathogenic or saprophytic leptospires. Mongolian gerbil is an appropriate experimental model to study the PAF-AH level in serum with its basal activity level comparable to that of human while elevated directly associated with the course of pulmonary hemorrhage during severe leptospirosis. Mortality occurred around the peak of pulmonary hemorrhage, along with the transition of the PAF-AH activity level in serum, from the increasing phase to the final decreasing phase. Limited clinical data indicated that the serum activity of PAF-AH was likely to be elevated in the patients infected by L. interrogans serogroup Icterohaemorrhagiae, but not in those infected by other less severe serogroups. Although L-PAF-AH might be released into the micro-environment via cell lysis, its PAF-AH activity apparently contributed little to this elevation. Therefore, the change of PAF-AH in serum not only may be influential for pulmonary hemorrhage, but also seems suitable for disease monitoring to ensure prompt clinical treatment, which is critical for reducing the mortality of severe leptospirosis

Molecular understanding of the suppression of new-particle formation by isoprene

Nucleation of atmospheric vapours produces more than half of global cloud condensation nuclei and so has an important influence on climate. Recent studies show that monoterpene (C10H16) oxidation yields highly oxygenated products that can nucleate with or without sulfuric acid. Monoterpenes are emitted mainly by trees, frequently together with isoprene (C5H8), which has the highest global emission of all organic vapours. Previous studies have shown that isoprene suppresses new-particle formation from monoterpenes, but the cause of this suppression is under debate. Here, in experiments performed under atmospheric conditions in the CERN CLOUD chamber, we show that isoprene reduces the yield of highly oxygenated dimers with 19 or 20 carbon atoms - which drive particle nucleation and early growth - while increasing the production of dimers with 14 or 15 carbon atoms. The dimers (termed C-20 and C-15, respectively) are produced by termination reactions between pairs of peroxy radicals (RO2 center dot) arising from monoterpenes or isoprene. Compared with pure monoterpene conditions, isoprene reduces nucleation rates at 1.7 nm (depending on the isoprene = monoterpene ratio) and approximately halves particle growth rates between 1.3 and 3.2 nm. However, above 3.2 nm, C-15 dimers contribute to secondary organic aerosol, and the growth rates are unaffected by isoprene. We further show that increased hydroxyl radical (OH center dot) reduces particle formation in our chemical system rather than enhances it as previously proposed, since it increases isoprene-derived RO2 center dot radicals that reduce C-20 formation. RO2 center dot termination emerges as the critical step that determines the highly oxygenated organic molecule (HOM) distribution and the corresponding nucleation capability. Species that reduce the C-20 yield, such as NO, HO2 and as we show isoprene, can thus effectively reduce biogenic nucleation and early growth. Therefore the formation rate of organic aerosol in a particular region of the atmosphere under study will vary according to the precise ambient conditions.Peer reviewe

A Modified DF2016 Criterion for the Fracture Modeling from Shear to Equibiaxial Tension

This study introduces a modified DF2016 criterion to model a ductile fracture of sheet metals from shear to equibiaxial tension. The DF2016 criterion is modified so that a material constant is equal to the fracture strain at equibiaxial tension, which can be easily measured by the bulging experiments. To evaluate the performance of the modified DF2016 criterion, experiments are conducted for QP980 with five different specimens with stress states from shear to equibiaxial tension. The plasticity of the steel is characterized by the Swift–Voce hardening law and the pDrucker function, which is calibrated with the inverse engineering approach. A fracture strain is measured by the XTOP digital image correlation system for all the specimens, including the bulging test. The modified DF2016 criterion is also calibrated with the inverse engineering approach. The predicted force–stroke curves are compared with experimental results to evaluate the performance of the modified DF2016 criterion on the fracture prediction from shear to equibiaxial tension. The comparison shows that the modified DF2016 criterion can model the onset of the ductile fracture with high accuracy in wide stress states from shear to plane strain tension. Moreover, the calibration of the modified DF2016 criterion is comparatively easier than the original DF2016 criterion

Preparation of Core-Shell Structure Magnetic Carbon-Based Solid Acid and its Catalytic Performance on Hemicellulose in Corncobs

Solid acid catalysts show good catalytic depolymerization behavior for lignocellulose. A stable core-shell structured magnetic solid acid catalyst (MSAC), Fe3O4/C-SO3H, was prepared from glucose, concentrated sulfuric acid, and modified magnetic particles of Fe3O4, which was used as the core. The effects of the carbonization and sulfonation processes on the activity of the catalyst were investigated. The results showed that preparation conditions had great influence on the quantity of the acidic groups (sulfonic, carboxyl, and hydroxyl groups) and the stability of magnetic catalysts. The best preparation conditions for MSAC were 3 h of carbonization time, 450 degrees C as the carbonization temperature, 9 h of sulfonation time, and 90 degrees C as the sulfonation temperature. Its surface topography, functional group, chemical composition, and magnetic properties were characterized by analysis instrument. Furthermore, the catalyst was stably dispersed in the reaction system, quickly separated from the reaction system using an external field, and reused many times; 44.3% of xylose yield was obtained at 160 degrees C for 16 h. The catalyst was used repeatedly more than 3 times, and the recovery over 89%. The depolymerization of corncobs was achieved by magnetic catalyst, representing the depolymerization characteristics of real lignocellulose. This data can be used as a reference for the subsequent use of biomass resource

Switchable Site-Selective Benzanilide C(sp²)-H Bromination via Promoter Regulation

Regioselective benzanilide bromination that generates either regioisomer from the same starting material is desirable. Herein, we develop switchable site-selective C(sp2)-H bromination by promoter regulation. This protocol leads to regiodivergent brominated benzanilide starting from the single substrate via selection of promoters. The protocol demonstrates excellent regioselectivity and good tolerance of functional groups with high yields. The utility effectiveness of this method has been well exemplified in the late-stage modification of biologically important molecules

Reliability, validity, and responsiveness of the simplified Chinese version of the knee injury and Osteoarthritis Outcome Score in patients after total knee arthroplasty

Objectives: The Knee Injury and Osteoarthritis Outcome Score (KOOS) has been utilized to evaluate short- and long-term outcomes in individuals following knee injuries, such as those with anterior cruciate ligament reconstruction and knee osteoarthritis, but has not yet been applied to individuals undergoing total knee arthroplasty (TKA) in China. The aim of this study was to assess the psychometric properties of the Simplified Chinese version of the KOOS in Chinese individuals undergoing TKA. Methods: This study distributed 170 questionnaires, and assessed the KOOS of the participants, along with requiring them to complete the Short Form 36 (SF-36) survey. There were 35 participants completed a test-retest reliability survey with a 24-h interval, 129 participants completed a pre - surgery survey, and 119 individuals completed a post - surgery survey 6 weeks after the surgery. The following tests were conducted: Cronbach's alpha (α) to assess internal consistency, intraclass correlation coefficient (ICC) to evaluate test-retest reliability, Spearman's correlation coefficient (ρ) to examine construct validity, effect size (ES) to detect measure responsiveness, minimal detectable change (MDC) to assess measurement errors. Floor and ceiling effects (<15%) were also asses evaluated. Results: The simplified Chinese version of the KOOS showed good test-retest reliability in participants after TKA, with an ICC of 0.82–0.97 (95% CI). The internal consistency of the five subscales of the KOOS was good (Cronbach's α = 0.70–0.96). No floor or ceiling effects were found. Regarding construct validity, a strong positive correlation was found between each of the three KOOS subscales (activities of daily living, knee-related Quality of Life, and sport and recreation subscales) and the general health and bodily pain subscales of the SF-36 (0.53 < ρ < 0.61). The subscales of the simplified Chinese version of the KOOS showed responsiveness (ES: 0.68 to 0.86) before and after 6 weeks of physical treatment. The MDC ranged from 10.28 to 23.24. Conclusions: The Chinese version of the KOOS showed good psychometric properties and was found to be valid, reliable, and simple as an assessment tool for symptoms, pain, activity of daily living, sports and recreational activity and quality of life for the Chinese population suffering from TKA

Long-term storage of lipid-like nanoparticles for mRNA delivery

Lipid-like nanoparticles (LLNs) have been extensively explored for messenger RNA (mRNA) delivery in various biomedical applications. However, the long-term storage of these nanoparticles is still a challenge for their clinical translation. In this study, we investigated a series of conditions for the long-term storage of LLNs with encapsulation of mRNA. We evaluated the stability of LLNs with different concentrations of cryoprotectants (sucrose, trehalose or mannitol) under the conditions of freezing or lyophilization processes. Through in vitro and in vivo mRNA delivery studies, we identified the optimal storage condition, and found that the addition with 5% (w/v) sucrose or trehalose to LLNs could remain their mRNA delivery efficiency for at least three months in the liquid nitrogen storage condition