pH-Dependent Aqueous-Phase Brown Carbon Formation: Rate Constants and Implications for Solar Absorption and Atmospheric Photochemistry.

Aqueous-phase reactions of α-dicarbonyls with amines or ammonium have been identified as important sources of secondary brown carbon (BrC). However, the kinetics of BrC formation and the effects of pH are still not very clear. In this study, the kinetics of BrC formation by aqueous reactions of α-dicarbonyls (glyoxal and methylglyoxal) with ammonium, amino acids, or alkylamines in bulk solution at different pH values are investigated. Our results reveal pH-parameterized BrC production rate constants, kBrCII (m-1 [M]-2 s-1), based on the light absorption between 300 and 500 nm: log10(kBrCII) = (1.0 ± 0.1) × pH - (7.4 ± 1.0) for reactions with glyoxal and log10(kBrCII) = (1.0 ± 0.1) × pH - (6.3 ± 0.9) for reactions with methylglyoxal. The linear slopes closing to 1.0 indicate that BrC formation is governed by the nitrogen nucleophilic addition pathway. Consequently, the absorptivities of the produced BrC increase exponentially with the increase of pH. BrC from reactions with methylglyoxal at higher pH (≥6.5) exhibits optical properties comparable to BrC from biomass burning or coal combustion, categorized as the "weakly" absorbing BrC, while BrC from reactions with methylglyoxal at lower pH (<6.0) or reactions with glyoxal (pH 5.0-7.0) falls into the "very weakly" absorbing BrC. The pH-dependent BrC feature significantly affects the solar absorption ability of the produced BrC and thus the atmospheric photochemical processes, e.g., BrC produced at pH 7.0 absorbs 14-16 times more solar power compared to that at pH 5.0, which in turn could lead to a decrease of 1 order of magnitude in the photolysis rate constants of O3 and NO2.

Aqueous-Phase Photoreactions of Mixed Aromatic Carbonyl Photosensitizers Yield More Oxygenated, Oxidized, and less Light-Absorbing Secondary Organic Aerosol (SOA) than Single Systems.

Aromatic carbonyls have been mainly probed as photosensitizers for aqueous secondary organic aerosol (aqSOA) and light-absorbing organic aerosol (i.e., brown carbon or BrC) formation, but due to their organic nature, they can also undergo oxidation to form aqSOA and BrC. However, photochemical transformations of aromatic carbonyl photosensitizers, particularly in multicomponent systems, are understudied. This study explored aqSOA formation from the irradiation of aromatic carbonyl photosensitizers in mixed and single systems under cloud/fog conditions. Mixed systems consisting of phenolic carbonyls only (VL + ActSyr + SyrAld: vanillin [VL] + acetosyringone [ActSyr] + syringaldehyde [SyrAld]) and another composed of both nonphenolic and phenolic carbonyls (DMB + ActSyr + SyrAld: 3,4-dimethoxybenzaldehyde [DMB], a nonphenolic carbonyl, + ActSyr + SyrAld) were compared to single systems of VL (VL*) and DMB (DMB*), respectively. In mixed systems, the shorter lifetimes of VL and DMB indicate their diminished capacity to trigger the oxidation of other organic compounds (e.g., guaiacol [GUA], a noncarbonyl phenol). In contrast to the slow decay and minimal photoenhancement for DMB*, the rapid photodegradation and significant photoenhancement for VL* indicate efficient direct photosensitized oxidation (i.e., self-photosensitization). Relative to single systems, the increased oxidant availability promoted functionalization in VL + ActSyr + SyrAld and accelerated the conversion of early generation aqSOA in DMB + ActSyr + SyrAld. Moreover, the increased availability of oxidizable substrates countered by stronger oxidative capacity limited the contribution of mixed systems to aqSOA light absorption. This suggests a weaker radiative effect of BrC from mixed photosensitizer systems than BrC from single photosensitizer systems. Furthermore, more oxygenated and oxidized aqSOA was observed with increasing complexity of the reaction systems (e.g., VL* < VL + ActSyr + SyrAld < VL + ActSyr + SyrAld + GUA). This work offers new insights into aqSOA formation by emphasizing the dual role of organic photosensitizers as oxidant sources and oxidizable substrates.

Obscured Contribution of Oxygenated Intermediate-Volatility Organic Compounds to Secondary Organic Aerosol Formation from Gasoline Vehicle Emissions.

Secondary organic aerosol (SOA) formation from gasoline vehicles spanning a wide range of emission types was investigated using an oxidation flow reactor (OFR) by conducting chassis dynamometer tests. Aided by advanced mass spectrometric techniques, SOA precursors, including volatile organic compounds (VOCs) and intermediate/semivolatile organic compounds (I/SVOCs), were comprehensively characterized. The reconstructed SOA produced from the speciated VOCs and I/SVOCs can explain 69% of the SOA measured downstream of an OFR upon 0.5-3 days' OH exposure. While VOCs can only explain 10% of total SOA production, the contribution from I/SVOCs is 59%, with oxygenated I/SVOCs (O-I/SVOCs) taking up 20% of that contribution. O-I/SVOCs (e.g., benzylic or aliphatic aldehydes and ketones), as an obscured source, account for 16% of total nonmethane organic gas (NMOG) emission. More importantly, with the improvement in emission standards, the NMOG is effectively mitigated by 35% from China 4 to China 6, which is predominantly attributed to the decrease of VOCs. Real-time measurements of different NMOG components as well as SOA production further reveal that the current emission control measures, such as advances in engine and three-way catalytic converter (TWC) techniques, are effective in reducing the "light" SOA precursors (i.e., single-ring aromatics) but not for the I/SVOC emissions. Our results also highlight greater effects of O-I/SVOCs to SOA formation than previously observed and the urgent need for further investigation into their origins, i.e., incomplete combustion, lubricating oil, etc., which requires improvements in real-time molecular-level characterization of I/SVOC molecules and in turn will benefit the future design of control measures.

Outcomes of antiretroviral treatment for 0-14-year-old children living with HIV in Ganzhou, China, 2006-2023.

BACKGROUND: Studies on antiretroviral therapy (ART) in children living with HIV (CLHIV) are limited due to the small population and low accession rate of ART. METHODS: All 0-14-year-old CLHIV admitted to the Ganzhou Center for Disease Control and Prevention from January 2006 to June 2023 were included retrospectively. The information of treatment regimens, disease progression, and laboratory tests of the patients under ART were used to explore the outcomes and impacts of long-term ART. The normality of all the data was tested by the Shapiro-Wilk test. RESULTS: From 2006 to 2023, 18 CLHIV were reported in Ganzhou. Among them, 11 received ART and were followed up for 60.0 ± 48.4 months. After receiving ART, the median viral load of them decreased from 89,600 copies/ml to 22 copies/ml (P = 0.007), the median CD4+ T cell count increased from 380.7 cells/µL to 661.9 cells/µL (P = 0.028), and the median CD8+ T cell count decreased from 1065.8 cells/µL to 983.3 cells/µL (P = 0.584). The laboratory test results regarding liver function, renal function, blood cell count, and glucolipid metabolism tended to be within normal reference ranges, and the mean height-for-age z-score and weight-for-age z-score increased. However, all the three CLHIV who received cotrimoxazole developed pneumocystis carinii pneumonia, upper respiratory infection, skin lesions, bacterial pneumonia and/or thrush; the mean body-mass-index-for-age z-score decreased from 0.52 to -0.63. CONCLUSION: For CLHIV, ART could effectively inhibit the replication of HIV and improve the immune function of patients. More studies that focus on ART in CLHIV are urgently needed.

Supramolecular-Interactions-Modulated Photoluminescence in Indium Bromide-Based Isomers.

Here, two isomeric ionic zero-dimensional indium bromide crystals of α (1)/ß (2)-[OPy][InBr4(Phen)] (OPy = N-octylpyridinium; Phen = 1,10-phenanthroline) have been isolated simply by changing the cooling conditions in solvothermal syntheses. Structural comparisons indicate their different supramolecular interactions, which can be confirmed by Hirshfeld surface analyses. The crystal 2 has additional hydrogen bonds and π-π interactions; as a result, the more compact stacking of 2 could result in a 10-fold higher photoluminescence (PL) quantum yield (PLQY) than that of 1. Density functional theory calculations confirm the electron transition from the inorganic moiety to the organic ligand, which provides a further understanding of the optical process. This work provides a new idea for designing PL indium-based halides by understanding the structure-PL relationship.

New Insights into the Brown Carbon Chromophores and Formation Pathways for Aqueous Reactions of α-Dicarbonyls with Amines and Ammonium.

Aqueous-phase reactions of α-dicarbonyls with ammonium or amines have been identified as important sources of secondary brown carbon (BrC). However, the identities of most chromophores in these reactions and the effects of pH remain largely unknown. In this study, the chemical structures, formation pathways, and optical properties of individual BrC chromophores formed through aqueous reactions of α-dicarbonyls (glyoxal and methylglyoxal) with ammonium, amino acids, or methylamine at different pH's were characterized in detail by liquid chromatography-photodiode array-high resolution tandem mass spectrometry. In total, 180 chromophores are identified, accounting for 29-79% of the light absorption of bulk BrC for different reactions. Thereinto, 155 newly identified chromophores, including 76 imidazoles, 57 pyrroles, 10 pyrazines, 9 pyridines, and 3 imidazole-pyrroles, explain additionally 9-69% of the light absorption, and these chromophores mainly involve four formation pathways, including previously unrecognized reactions of ammonia or methylamine with the methylglyoxal dimer for the formation of pyrroles. The pH in these reactions also shows remarkable effects on the formation and transformation of BrC chromophores; e.g., with the increase of pH from 5.0 to 7.0, the light absorption contributions of imidazoles in identified chromophores decrease from 72% to 65%, while the light absorption contributions of pyrazines increase from 5% to 13% for the methylglyoxal + ammonium reaction; meanwhile, more small nitrogen heterocycles transformed into oligomers (e.g., C9 and C12 pyrroles) via reaction with methylglyoxal. These newly identified chromophores and proposed formation pathways are instructive for future field studies of the formation and transformation of aqueous-phase BrC.

Enigma of Urban Gaseous Oxygenated Organic Molecules: Precursor Type, Role of NOx, and Degree of Oxygenation.

Oxidation of volatile organic compounds (VOCs) forms oxygenated organic molecules (OOMs), which contribute to secondary pollution. Herein, we present measurement results of OOMs using chemical ionization mass spectrometry with nitrate as the reagent ion in Shanghai. Compared to those in forests and laboratory studies, OOMs detected at this urban site were of relatively lower degree of oxygenation. This was attributed to the high NOx concentrations (∼44 ppb), which overall showed a suppression on the propagation reactions. As another result, a large fraction of nitrogenous OOMs (75%) was observed, and this fraction further increased to 84% under a high NO/VOC ratio. By applying a novel framework on OOM categorization and supported by VOC measurements, 50 and 32% OOMs were attributed to aromatic and aliphatic precursors, respectively. Furthermore, aromatic OOMs are more oxygenated (effective oxygen number, nOeff = 4-6) than aliphatic ones (nOeff = 3-4), which can be partly explained by the difference in initiation mechanisms and points to possible discrimination in termination reactions. This study highlights the roles of NOx in OOM formation in urban areas, as well as the formation of nitrogenous products that might show discrimination between aromatic and aliphatic VOCs.

Molecular Characterization of Oxygenated Organic Molecules and Their Dominating Roles in Particle Growth in Hong Kong.

Oxygenated organic molecules (OOMs) are critical intermediates linking volatile organic compound oxidation and secondary organic aerosol (SOA) formation. Yet, the understanding of OOM components, formation mechanism, and impacts are still limited, especially for urbanized regions with a cocktail of anthropogenic emissions. Herein, ambient measurements of OOMs were conducted at a regional background site in South China in 2018. The molecular characteristics of OOMs revealed dominant nitrogen-containing products, and the influences of different factors on OOM composition and oxidation state were elucidated. Positive matrix factorization analysis resolved the complex OOM species to factors featured with fingerprint species from different oxidation pathways. A new method was developed to identify the key functional groups of OOMs, which successfully classified the majority species into carbonyls (8%), hydroperoxides (7%), nitrates (17%), peroxyl nitrates (10%), dinitrates (13%), aromatic ring-retaining species (6%), and terpenes (7%). The volatility estimation of OOMs was improved based on their identified functional groups and was used to simulate the aerosol growth process contributed by the condensation of those low-volatile OOMs. The results demonstrate the predominant role of OOMs in contributing sub-100 nm particle growth and SOA formation and highlight the importance of dinitrates and anthropogenic products from multistep oxidation.

Homocysteine Suppresses Autophagy Through AMPK-mTOR-TFEB Signaling in Human THP-1 Macrophages.

ABSTRACT: Hyperhomocysteinemia is an independent risk factor for atherosclerosis. It is known that macrophage autophagy plays a protective role in atherosclerosis and that hyperhomocysteinemia is strongly linked to autophagy. Therefore, it is of great significance to study the molecular mechanisms underlying the effect of homocysteine (Hcy) on macrophage autophagy. This study aimed to investigate the effects of Hcy on autophagy in a human acute monocytic leukemia cell line (THP-1). The Hcy-treated THP-1 cells exhibited increased levels of the autophagy substrate SQSTM1 (p62) and decreased levels of the autophagy markers LC3 II/I and Beclin-1, indicating a decrease in autophagy in vitro. Furthermore, Western blotting showed that Hcy significantly increased the levels of p-mTOR and nuclear TFEB and decreased the levels of p-AMPK and cytoplasmic TFEB. These data suggest that Hcy inhibits autophagosome formation in human THP-1 macrophages through the AMPK-mTOR-TFEB signaling pathway. Our findings provide new insights into the mechanisms of atherosclerotic diseases caused by Hcy.

A nomogram predicts cardiovascular events in patients with peritoneal dialysis-associated peritonitis.

OBJECTIVE: To predict the risk factors for cardiovascular events within 5 years in patients with peritoneal dialysis-associated peritonitis and establish a nomogram for clinical prediction. METHODS: A prediction model was established by conducting an observational study in 150 patients with peritoneal dialysis-associated peritonitis obtained from the Information Database of AnHui Medical University Affiliated Hospital. The nomogram was constructed using the multivariate COX regression model. The C-index and the calibration plot were used to assess the discrimination and calibration of the prediction model. RESULTS: The elderly [HR = 2.453 (1.071-5.619)], history of cardiovascular events [HR = 2.296 (1.220-4.321)], alkaline phosphatase [HR = 1.004 (1.002-1.005)] and culture-positive [HR= 2.173 (1.009-4.682)] were identified as risk predictors of cardiovascular events, while serum albumin [HR = 0.396(0.170-0.924)] was identified as protective predictors of cardiovascular events. Combined with clinical studies, we constructed a nomogram based on the minimum value of the Akaike Information Criterion or Bayesian Information Criterion. The C index of the nomogram is 0.732, revealing great discrimination and appropriate calibration. Through the total score of the nomogram and the result of ROC, we classify patients into high-risk groups (cardiovascular events group) and low-risk groups (no cardiovascular events group). Cardiovascular events were significantly different for patients in the high-risk group compared to the low-risk group (HR = 3.862(2.202-6.772; p < 0.001). CONCLUSIONS: The current novel nomogram can accurately predict cardiovascular events in patients with peritonitis associated with peritoneal dialysis. However, external validation is required before the model can be used in clinic settings.

Transcriptome revealed the molecular mechanism of Glycyrrhiza inflata root to maintain growth and development, absorb and distribute ions under salt stress.

BACKGROUND: Soil salinization extensively hampers the growth, yield, and quality of crops worldwide. The most effective strategies to counter this problem are a) development of crop cultivars with high salt tolerance and b) the plantation of salt-tolerant crops. Glycyrrhiza inflata, a traditional Chinese medicinal and primitive plant with salt tolerance and economic value, is among the most promising crops for improving saline-alkali wasteland. However, the underlying molecular mechanisms for the adaptive response of G. inflata to salinity stress remain largely unknown. RESULT: G. inflata retained a high concentration of Na+ in roots and maintained the absorption of K+, Ca2+, and Mg2+ under 150 mM NaCl induced salt stress. Transcriptomic analysis of G. inflata roots at different time points of salt stress (0 min, 30 min, and 24 h) was performed, which resulted in 70.77 Gb of clean data. Compared with the control, we detected 2645 and 574 differentially expressed genes (DEGs) at 30 min and 24 h post-salt-stress induction, respectively. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses revealed that G. inflata response to salt stress post 30 min and 24 h was remarkably distinct. Genes that were differentially expressed at 30 min post-salt stress induction were enriched in signal transduction, secondary metabolite synthesis, and ion transport. However, genes that were differentially expressed at 24 h post-salt-stress induction were enriched in phenylpropane biosynthesis and metabolism, fatty acid metabolism, glycerol metabolism, hormone signal transduction, wax, cutin, and cork biosynthesis. Besides, a total of 334 transcription factors (TFs) were altered in response to 30 min and 24 h of salt stress. Most of these TFs belonged to the MYB, WRKY, AP2-EREBP, C2H2, bHLH, bZIP, and NAC families. CONCLUSION: For the first time, this study elucidated the salt tolerance in G. inflata at the molecular level, including the activation of signaling pathways and genes that regulate the absorption and distribution of ions and root growth in G. inflata under salt stress conditions. These findings enhanced our understanding of the G. inflata salt tolerance and provided a theoretical basis for cultivating salt-tolerant crop varieties.

Distribution characteristics of drug resistance mutations of HIV CRF01_AE, CRF07_BC and CRF08_BC from patients under ART in Ganzhou, China.

BACKGROUND: Drug resistance mutation (DRM)-associated virological failure has become a critical issue for ART and the elimination of HIV. OBJECTIVES: To investigate the distribution characteristics of DRMs of HIV CRF01_AE, CRF07_BC and CRF08_BC, the predominant subtypes in China. METHODS: Patients receiving ART up to 31 August 2020 in Ganzhou in China were recruited. Full-length sequences of the HIV pol gene were amplified from patients with virological failure. DRMs and antiretroviral susceptibility were explored using the Stanford University HIV Drug Resistance Database HIVdb Program. RESULTS: Overall, 279 of 2204 patients under ART were found to have virological failure. Nine HIV subtypes were identified among 211 sequences that were amplified successfully and CRF08_BC (37.0%), CRF01_AE (26.1%) and CRF07_BC (25.6%) were the most prevalent, with mutation frequencies of 44.9% (35/78), 52.7% (29/55) and 35.2% (19/54), respectively. The most common DRMs of these three subtypes were K103N and M184V, while the mutation frequencies of M41L, D67N, K70R, K101E, V106M, Y181C, K219E, H221Y and N348I were obviously different among subtypes. The resistance levels and frequencies for antiretroviral drugs for these three subtypes were similar and resistances to nevirapine, efavirenz, lamivudine and emtricitabine were the most frequently observed. Compared with CRF01_AE and CRF07_BC, CRF08_BC had higher proportions of DRMs for NRTIs and lower frequencies of resistance to NRTIs and NNRTIs. CONCLUSIONS: The distribution characteristics of DRMs of HIV CRF01_AE, CRF07_BC and CRF08_BC were inconsistent and should be considered when selecting antiretroviral strategies, developing new drugs and controlling HIV strains containing DRMs.

Comparative Assessment of Cooking Emission Contributions to Urban Organic Aerosol Using Online Molecular Tracers and Aerosol Mass Spectrometry Measurements.

Cooking organic aerosol (COA) is an important source of particulate pollutants in urbanized regions. Yet, the diversity and complexity of COA components make direct identification and quantification of COA difficult. In this study, we conducted collocated OA measurements with an aerosol mass spectrometer (AMS) and a thermal desorption aerosol gas chromatography-mass spectrometer (TAG) in Shanghai. Cooking molecular tracers (e.g., C18 fatty acids, azelaic acid) measured by TAG provide unambiguous source information for evaluating the tracer ion (C6H10O+, m/z 98) used for identification and apportionment of COA in AMS analysis. Based on the collocated AMS and TAG measurements, two COA factors, namely, a primary COA (PCOA) and an oxygenated COA (OCOA) produced from rapid oxygenation of freshly emitted PCOA, were identified. Criteria for identifying COA factors from AMS analysis with different oxygenation levels are proposed, i.e., characteristic mass spectra, temporal variations, etc. Furthermore, two positive matrix factorization approaches, namely, AMS-PMF and the molecular marker (MM)-PMF, were compared for COA quantification, where high consistency was found with the contribution of COA to total PM2.5 mass estimated to be 9 ± 7% by AMS-PMF and 6 ± 5% by the MM-PMF. Our study highlights the important impacts of cooking activities on air quality in urban areas. We also demonstrate the advantage of conducting collocated measurements using multiple high time resolution mass spectrometric techniques in advancing our understanding of atmospheric OA chemistry and improving the accuracy of source apportionment.

Enhanced Nitrite Production from the Aqueous Photolysis of Nitrate in the Presence of Vanillic Acid and Implications for the Roles of Light-Absorbing Organics.

A prominent source of hydroxyl radicals (•OH), nitrous acid (HONO) plays a key role in tropospheric chemistry. Apart from direct emission, HONO (or its conjugate base nitrite, NO2-) can be formed secondarily in the atmosphere. Yet, how secondary HONO forms requires elucidation, especially for heterogeneous processes involving numerous organic compounds in atmospheric aerosols. We investigated nitrite production from aqueous photolysis of nitrate for a range of conditions (pH, organic compound, nitrate concentration, and cation). Upon adding small oxygenates such as ethanol, n-butanol, or formate as •OH scavengers, the average intrinsic quantum yield of nitrite [Φ(NO2-)] was 0.75 ± 0.15%. With near-UV-light-absorbing vanillic acid (VA), however, the effective Φ(NO2-) was strongly pH-dependent, reaching 8.0 ± 2.1% at a pH of 8 and 1.5 ± 0.39% at a more atmospherically relevant pH of 5. Our results suggest that brown carbon (BrC) may greatly enhance the nitrite production from the aqueous nitrate photolysis through photosensitizing reactions, where the triplet excited state of BrC may generate solvated electrons, which reduce nitrate to NO2 for further conversion to nitrite. This photosensitization process by BrC chromophores during nitrate photolysis under mildly acidic conditions may partly explain the missing HONO in urban environments.

Preoperative proteinuria may be a risk factor for postoperative acute kidney injury：a meta-analysis.

OBJECTIVE: To investigate the relationship between preoperative proteinuria and postoperative acute kidney injury (AKI). METHODS: We performed a search on databases included PubMed, Embase, the Cochrane Library, and Web of Science, from December 2009 to September 2020. Data extracted from eligible studies were synthesized to calculate the odds ratio (OR) and 95% confidence interval (CI). A fixed or random effects model was applied to calculate the pooled OR based on heterogeneity through the included studies. RESULTS: This meta-analysis of 11 observational studies included 203,987 participants, of whom 21,621 patients suffered from postoperative AKI and 182,366 patients did not suffer from postoperative AKI. The combined results demonstrated that preoperative proteinuria is an independent risk factor for postoperative AKI (adjusted OR = 1.65, 95%CI:1.44-1.89, p < 0.001). Subgroup analysis showed that both preoperative mild proteinuria (adjusted OR = 1.30, 95%CI:1.24-1.36, p < 0.001) and preoperative heavy proteinuria (adjusted OR = 1.93, 95%CI:1.65-2.27, p < 0.001) were independent risk factors for postoperative AKI. The heterogeneity was combined because its values were lower. Further subgroup analysis found that preoperative proteinuria measured using dipstick was an independent risk factor for postoperative AKI (adjusted OR = 1.48, 95%CI:1.37-1.60, p < 0.001). Finally, preoperative proteinuria was an independent risk factor for postoperative AKI in the non-cardiac surgery group (adjusted OR = 2.06, 95%CI:1.31-3.24, p = 0.002) and cardiac surgery group (adjusted OR = 1.69, 95%CI:1.39-2.06, p < 0.001). CONCLUSION: Preoperative proteinuria is an independent risk factor for postoperative AKI and in instances when proteinuria is detected using dipsticks.

Heterogeneous Oxidation of SO2 in Sulfate Production during Nitrate Photolysis at 300 nm: Effect of pH, Relative Humidity, Irradiation Intensity, and the Presence of Organic Compounds.

Heterogeneous oxidation of SO2 is one of the promising mechanisms to account for high loading of sulfate during severe haze periods in China. Our earlier work reported on the SO2 oxidation by OH and NO2 produced during 250 nm nitrate photolysis (Environ. Sci. Technol. Lett. 2019, 6, 86-91). Here, we extend that work to examine sulfate production during nitrate photolysis at 300 nm irradiation, which can additionally generate NO2- or HNO2, N(III). Flow cell/in situ Raman experiments showed that the reactive uptake coefficient of SO2, γSO2, can be expressed as γSO2 = 1.64 × pNO3-, where pNO3- is the nitrate photolysis rate in the range of (1.0-8.0) × 10-5 M s-1. Our kinetic model with the pNO3- predicts that N(III) is the main contributor to the SO2 oxidation, followed by NO2 contribution. Furthermore, the addition of OH scavengers (e.g., glyoxal or oxalic acid) does not suppress the sulfate production because of the reduced N(III)-consuming reactions and the high particle pH sustained by their presence. Our calculations illustrate that under characteristic haze conditions, the nitrate photolysis mechanism can produce sulfate at ∼1 µg m-3 h-1 at pH 4-6 and pNO3- = 10-5 M s-1. The present study highlights the importance of in-particle nitrate photolysis in heterogeneous oxidation of SO2 by reactive nitrogen (NO2-/HNO2 and NO2) under atmospherically relevant actinic irradiation. However, the nitrate photolysis rate constant needs to be better constrained for ambient aerosols.

Estimating Secondary Organic Aerosol Production from Toluene Photochemistry in a Megacity of China.

The production of secondary organic aerosols (SOA) from toluene photochemistry in Shanghai, a megacity of China, was estimated by two approaches, the parametrization method and the tracer-based method. The temporal profiles of toluene, together with other fifty-six volatile organic compounds (VOCs), were characterized. Combing with the vapor wall loss corrected SOA yields derived from chamber experiments, the estimated toluene SOA by the parametrization method as embodied in the two-product model contributes up to ∼40% of the total SOA budget during summertime. 2,3-Dihydroxy-4-oxopentanoic acid (DHOPA), a unique product from the OH-initiated oxidation of toluene in the presence of elevated NOx, was used as a tracer to back calculate the toluene SOA concentrations. By taking account for the effect of gas-particle partitioning processes on the fraction of DHOPA in the particle phase, the estimated toluene SOA concentrations agree within ∼33% with the estimates by the parametrization method. The agreement between these two independent approaches highlight the need to update current model frameworks with recent laboratory advances for a more accurate representation of SOA formation in regions with substantial anthropogenic emissions.

Tetramethylpyrazine exerts a protective effect against injury from acute myocardial ischemia by regulating the PI3K/Akt/GSK-3ß signaling pathway.

OBJECTIVE: We investigated the protective effect of tetramethylpyrazine (TMP) on injury related to acute myocardial ischemia (AMI) induced by isoproterenol (ISO). MATERIALS AND METHODS: Rats were randomly assigned to five groups: control, ISO, ISO + propranolol (10 mg/kg), ISO + TMP (10 mg/kg) and ISO + TMP (20 mg/kg). The rats in the three ISO + groups were pretreated with propranolol or TMP, while the rats in the control and ISO groups were pretreated with an equal volume of saline. Afterwards, the rats in the four administration groups were subcutaneously injected with ISO for two consecutive days. The levels of creatine kinase (CK), lactate dehydrogenase (LDH), superoxide dismutase (SOD), malondialdehyde (MDA), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and IL-1ß in the serum were measured using ELISA. The expressions of B-cell lymphoma-associated X-2 (Bax-2), B-cell lymphoma-2 (Bcl-2), phosphoinositide-3-kinase (PI3K), protein kinase B (Akt), glycogen synthase kinase 3ß (GSK-3ß), MDA5 and SOD1 were determined using western blotting assay. The phosphorylation of PI3K, Akt and GSK-3ß were also determined using western blotting assay. The left ventricles of the rats were extracted and stained using hematoxylin and eosin (H&E). The ST segment was recorded using electrocardiograms (ECGs). RESULTS: Administration of TMP (10, 20 mg/kg) reduced the levels of MDA and CK and the activities of SOD and LDH in the serum. Pretreatment with TMP significantly reduced the levels of pro-inflammatory cytokines, including IL-1ß, IL-6 and TNF-α. Treatment with TMP also improved the histopathological alteration and decreased the ST elevation. Furthermore, TMP ameliorated the expressions of Cu, SOD1, MDA5, Bax-2, Bcl-2, p-PI3K, p-Akt and p-GSK-3ß in ISO-induced rats. CONCLUSIONS: Tetramethylpyrazine protected against injury due to AMI by regulating the PI3K/Akt /GSK-3ß signaling pathway.

STAT3 rs4796793 contributes to lung cancer risk and clinical outcomes of platinum-based chemotherapy.

BACKGROUND: Signal transducer and activator of transcription (STAT) 3 plays a vital role in carcinogenesis and drug response. Platinum-based chemotherapy is the first-line treatment for lung cancer patients, especially those in advanced stages. In the present study, we investigated the association of STAT3 polymorphism rs4796793 with lung cancer susceptibility, platinum-based chemotherapy response, and toxicity. METHODS: A total of 498 lung cancer patients and 213 healthy controls were enrolled in the study. 467 of them received at least 2-cycle platinum-based chemotherapy. Unconditional logistical regression analysis was used to assess the associations. RESULTS: STAT3 rs4769793 G allele carriers had an increased susceptibility of lung cancer [additive model: adjusted OR (95% CI) 1.376 (1.058-1.789), P = 0.017; recessive model: adjusted OR (95% CI) 1.734 (1.007-2.985), P = 0.047]. Rs4769793 was not significantly associated with platinum-based chemotherapy response in lung cancer patients. STAT3 rs4796793 was associated with an increased risk of severe overall toxicity [additive model: adjusted OR (95% CI) 1.410 (1.076-1.850), P = 0.013; dominant model: adjusted OR (95% CI) 1.638 (1.091-2.459), P = 0.017], especially hematological toxicity [additive model: adjusted OR (95% CI) 1.352 (1.001-1.826), P = 0.049]. CONCLUSIONS: STAT3 rs4796793 may be considered as a potential candidate biomarker for the prediction of susceptibility and prognosis in Chinese lung cancer patients. However, well-designed studies with larger sample sizes are required to verify the results.

Stable Hierarchical Bimetal-Organic Nanostructures as HighPerformance Electrocatalysts for the Oxygen Evolution Reaction.

The integration of heterometallic units and nanostructures into metal-organic frameworks (MOFs) used for the oxygen evolution reaction (OER) can enhance the electrocatalytic performance and help elucidate underlying mechanisms. We have synthesized a series of stable MOFs (CTGU-10a1-d1) based on trinuclear metal carboxylate clusters and a hexadentate carboxylate ligand with a (6,6)-connected nia net. We also present a strategy to synthesize hierarchical bimetallic MOF nanostructures (CTGU-10a2-d2). Among these, CTGU-10c2 is the best material for the OER, with an overpotential of 240 mV at a current density of 10 mA cm-2 and a Tafel slope of 58 mV dec-1 . This is superior to RuO2 and confirms CTGU-10c2 as one of the few known high-performing pure-phase MOF-OER electrocatalysts. Notably, bimetallic CTGU-10b2 and c2 show an improved OER activity over monometallic CTGU-10a2 and d2. Both DFT and experiments show that the remarkable OER performance of CTGU-10c2 is due to the presence of unsaturated metal sites, a hierarchical nanobelt architecture, and the Ni-Co coupling effect.