Quantifying HONO Production from Nitrate Photolysis in a Polluted Atmosphere.

The photolysis of particulate nitrate (pNO3-) has been suggested to be an important source of nitrous acid (HONO) in the troposphere. However, determining the photolysis rate constant of pNO3- (jpNO3-) suffers from high uncertainty. Prior laboratory measurements of jpNO3- using aerosol filters have been complicated by the "shadow effect"─a phenomenon of light extinction within aerosol layers that potentially skews these measurements. We developed a method to correct the shadow effect on the photolysis rate constant of pNO3- for HONO production (jpNO3- â†’ HONO) using aerosol filters with identical chemical compositions but different aerosol loadings. We applied the method to quantify jpNO3- â†’ HONO over the North China Plain (NCP) during the winter haze period. After correcting for the shadow effect, the normalized average jpNO3- â†’ HONO at 5 °C increased from 5.89 × 10-6 s-1 to 1.72 × 10-5 s-1. The jpNO3- â†’ HONO decreased with increasing pH and nitrate proportions in PM2.5 and had no correlation with nitrate concentrations. A parametrization for jpNO3- â†’ HONO was developed for model simulation of HONO production in NCP and similar environments.

Resistance to Planthoppers and Southern Rice Black-Streaked Dwarf Virus in Rice Germplasms.

The damage caused by the white-back planthopper (WBPH, Sogatella furcifera) and brown planthopper (BPH, Nilaparvata lugens), as well as southern rice black-streaked dwarf virus (SRBSDV), considerably decreases the grain yield of rice. Identification of rice germplasms with sufficient resistance to planthoppers and SRBSDV is essential to the breeding and deployment of resistant varieties and, hence, the control of the pests and disease. In this study, 318 rice accessions were evaluated for their reactions to the infestation of both BPH and WBPH at the seedling stage using the standard seed-box screening test method; insect quantification was further conducted at the end of the tillering and grain-filling stages in field trials. Accessions HN12-239 and HN12-328 were resistant to both BPH and WBPH at all tested stages. Field trials were conducted to identify resistance in the collection to SRBSDV based on the virus infection rate under artificial inoculation. Rathu Heenati (RHT) and HN12-239 were moderately resistant to SRBSDV. In addition, we found that WBPH did not penetrate stems with stylets but did do more probing bouts and xylem sap ingestion when feeding on HN12-239 than the susceptible control rice Taichung Native 1. The resistance of rice accessions HN12-239, HN12-328, and RHT to BPH, WBPH, and/or SRBSDV should be valuable to the development of resistant rice varieties.

Evolution of Ozone Formation Sensitivity during a Persistent Regional Ozone Episode in Northeastern China and Its Implication for a Control Strategy.

In recent years, the magnitude and frequency of regional ozone (O3) episodes have increased in China. We combined ground-based measurements, observation-based model (OBM), and the Weather Research and Forecasting and Community Multiscale Air Quality (WRF-CMAQ) model to analyze a typical persistent O3 episode that occurred across 88 cities in northeastern China during June 19-30, 2021. The meteorological conditions, particularly the wind convergence centers, played crucial roles in the evolution of O3 pollution. Daily analysis of the O3 formation sensitivity showed that O3 formation was in the volatile organic compound (VOC)-limited or transitional regime at the onset of the pollution episode in 92% of the cities. Conversely, it tended to be or eventually became a NOx-limited regime as the episode progressed in the most polluted cities. Based on the emission-reduction scenario simulations, mitigation of the regional O3 pollution was found to be most effective through a phased control strategy, namely, reduction of a high ratio of VOCs to NOx at the onset of the pollution and lower ratio during evolution of the O3 episode. This study presents a new possibility for regional O3 pollution abatement in China based on a reasonable combination of OBM and the WRF-CMAQ model.

The attitudes of postgraduate medical students towards the curriculum by degree type: a large-scale questionnaire survey.

BACKGROUND: Chinese medical schools have offered both professional and academic degrees for postgraduate students. However, there is limited information about the attitudes of professional-degree and academic-degree students. We aimed to examine the attitudes of full-time postgraduate students towards the curriculum, stratified by degree type. METHODS: A 29-item online questionnaire was distributed to postgraduate students in West China School of Medicine of Sichuan University in 2020. The questionnaire was designed to collect students' demographic characteristics, attitudes towards curricular provision and content, and classroom organization. A comparison was made between groups based on degree type (academic degree versus professional degree). RESULTS: Overall, 645 out of 908 students at West China School of Medicine completed the questionnaire. Comparing with students pursuing academic degrees, professional-degree students were more interested if the curriculum included specialized knowledge and clinical skills, and expressed concerns over the excessive compulsory courses and inadequate optional courses (p < 0.001), particularly prominent among first-year postgraduate students. Besides, a greater proportion of professional-degree students thought the curriculum was conflict with clinical work to some extent, and they also rated taking attendance in class as less reasonable (p < 0.01). Conversely, students pursuing academic degrees expressed that the courses were inadequate in interdisciplinary curriculum and had some crossover or repetition, and they assigned a higher importance rating for the curriculum when comparing professional-degree students (all p < 0.05). CONCLUSIONS: Different attitudes toward the curriculum are observed between students pursuing professional degrees and those pursuing academic degrees. This study provides benchmark data for future postgraduate course reforms in China.

Pathological Changes of Small Vessel Disease in Intracerebral Hemorrhage: a Systematic Review and Meta-analysis.

In intracerebral hemorrhage (ICH) with pathology-proven etiology, we performed a systematic review and meta-analysis to elucidate the association between cerebral amyloid angiopathy (CAA) and arteriolosclerosis, and directly compared MRI and pathological changes of markers of cerebral small vessel disease (CSVD). Studies enrolling primary ICH who had received an etiological diagnosis through biopsy or autopsy were searched using Ovid MEDLINE, PubMed, and Web of Science from inception to June 8, 2022. We extracted pathological changes of CSVD for each patient whenever available. Patients were grouped into CAA + arteriolosclerosis, strict CAA, and strict arteriolosclerosis subgroups. Of 4155 studies identified, 28 studies with 456 ICH patients were included. The frequency of lobar ICH (p<0.001) and total microbleed number (p=0.015) differed among patients with CAA + arteriolosclerosis, strict CAA, and strict arteriolosclerosis. Concerning pathology, severe CAA was associated with arteriolosclerosis (OR 6.067, 95% CI 1.107-33.238, p=0.038), although this association was not statistically significant after adjusting for age and sex. Additionally, the total microbleed number (median 15 vs. 0, p=0.006) was higher in ICH patients with CAA evidence than those without CAA. The pathology of CSVD imaging markers was mostly investigated in CAA-ICH. There was inconsistency concerning CAA severity surrounding microbleeds. Small diffusion-weighted imaging lesions could be matched to acute microinfarct histopathologically. Studies that directly correlated MRI and pathology of lacunes, enlarged perivascular spaces, and atrophy were scarce. Arteriolosclerosis might be associated with severe CAA. The pathological changes of CSVD markers by ICH etiology are needed to be investigated further.

Summertime carbonyl compounds in an urban area in the North China Plain: Identification of sources, key precursors and their contribution to O3 formation.

Carbonyl compounds are critical components of volatile organic compounds, which significantly participate in the photochemical formation of atmospheric ozone and thus threaten human health. Here we measured 15 C1-C8 carbonyl compounds at an urban site in Linyi, a typically industrialised city in the North China Plain (NCP). Formaldehyde (3.89 ppbv), acetaldehyde (1.66 ppbv) and acetone (2.03 ppbv) were found to be the top three carbonyl compounds, accounting for 76.11% of the total concentration of carbonyl compounds. Anthropogenic secondary formation was recognised as the main source of the top five carbonyl compounds, which included formaldehyde, acetaldehyde, acetone, butyraldehyde and benzaldehyde, and accounted for 46-54% of all sources. Alkenes were the most important precursors of formaldehyde and acetaldehyde, suggesting that reducing the emission of alkenes from anthropogenic sources is an effective way to control carbonyl compound pollution in Linyi. Furthermore, the photolysis of carbonyl compounds played a significant role (68-75%) as sources of HO2• and RO2• and thus made a significant contribution (14.6%) to the photochemical formation of O3. This study highlights the importance of anthropogenic secondary formation as a source of carbonyl compounds and provides a scientific basis for O3 pollution control in carbonyl compound-enriched cities in the NCP.

Modulation effect of vaginal mucosal microflora and susceptibility to Neisseria gonorrhoeae infections: a systematic review and meta-analysis.

OBJECTIVE: The vaginal microbiota may modulate susceptibility to Neisseria gonorrhea (NG) infections. The objective of this meta-analysis was to evaluate the association between these NG infections and the vaginal microbiota. METHOD: A systematic review and meta-analysis was conducted to investigate the correlation of vaginal microbiota and NG risk. Primary sources of the reviewed studies were from inception through December 2018. Vaginal mucosa microflora were dichotomized into high-Lactobacillus vaginal microbiota and low-Lactobacillus vaginal microbiota (LL-VMB), using either Nugent score, Amsel's criteria, presence of clue cells or 16S rRNA gene sequencing. RESULTS: A total of 8 studies qualified for inclusion in this meta-analysis. LL-VMB could be regarded as worse prognostic factor, and the pooled OR was 1.33 (95% CI 1.02, 1.73; P = 0.04, I2 = 44%). LL-VMB was associated with a significantly higher susceptibility of NG. Trend for the sensitive analysis was consistence with the primary outcome. Significant publication bias was not detected by the funnel plot. CONCLUSION: In conclusion, the systematic review and meta-analysis has demonstrated that LL-VMB was significantly associated with a high NG susceptibility.

Lipoxin A4 inhibits lipopolysaccharide-induced production of inflammatory cytokines in keratinocytes by up-regulating SOCS2 and down-regulating TRAF6.

Liopxin A4 (LXA4) is considered to be a crucial modulator in the inflammatory responses. In the present study, we aimed to study the effect of LXA4 on the inflammatory cytokines production induced by lipopolysaccharide (LPS) and the possible mechanism in normal human epidermal keratinocytes (NHEKs). NHEKs were isolated and cultured. The expression of toll-like receptor 4 (TLR4), LXA4 receptor (ALXR) and aryl hydrocarbon receptor (AhR) in NHEKs was detected by reverse transcription polymerase chain reaction (RT-PCR). The mRNA and protein levels of tumor necrosis factor-alpha (TNF-α) and interleukin-1ß (IL-1ß) were determined in NHEKs stimulated by LPS (10 µg/mL) with or without preincubation with LXA4 (100 nmol/L) for 30 min by real-time quantitative PCR (real-time qPCR) and enzyme-linked immunosorbent assay (ELISA), respectively. The expression levels of tumor necrosis factor receptor-associated factor 6 (TRAF6) and suppressors of cytokine signaling 2 (SOCS2) mRNAs and proteins, and nuclear translocation of NF-kB-p65 were measured by real-time qPCR and Western blotting, respectively. The results showed that NHEKs expressed TLR4, ALXR and AhR. LXA4 significantly inhibited the mRNA and protein expression levels of TNF-α, IL-1ß and TRAF6 induced by LPS in NHEKs, and LXA4 obviously increased the expression of SOCS2 at mRNA and protein levels. The nuclear NF-kB-p65 protein expression induced by LPS was inhibited after preincubation with LXA4 in NHEKs. It was concluded that LXA4 inhibits the LPS-induced production of TNF-α and IL-1ß in NHEKs by up-regulating SOCS2 and down-regulating TRAF6.

Lipoxin A4 inhibits proliferation and inflammatory cytokine/chemokine production of human epidermal keratinocytes associated with the ERK1/2 and NF-κB pathways.

BACKGROUND: Current in vitro studies show that lipoxin A4 (LXA4) has multiple biological functions including inhibiting cell proliferation and inflammatory cytokine production. Our previous studies showed LXA4 could inhibit the expression of IL-6 and IL-8 in normal human epidermal keratinocytes (NHEKs). However, more specific effects including regulation of cell proliferation and anti-inflammatory mechanisms of LXA4 in NHEKs have not been previously studied. OBJECTIVE: We proposed to investigate the effects of LXA4 on cell proliferation and inflammatory cytokine/chemokine production in NHEKs, and the possible molecular mechanisms of cell cycle and anti-inflammatory signal transduction pathway. METHODS: NHEKs were stimulated with LPS, with or without preincubation with LXA4. Cell proliferation and cell cycle of NHEKs were examined by WST-8, CFSE assay and DNA staining, respectively. The mRNA and protein levels of inflammatory cytokines were quantified by real-time quantitative PCR and ELISA. The expressions of signaling proteins cyclin D1, P16INK4A, ERK1/2 and NF-κB-p65 were analyzed using Western blotting. RESULTS: Cell proliferation and inflammatory cytokine/chemokine production of NHEKs were suppressed by LXA4, which caused G0/G1 phase cell cycle arrest in NHEKs. The expression of cyclin D1 was down-regulated by LXA4, contrary to the results of P16INK4A. The ERK1/2 phosphorylation and NF-κB-p65 nuclear translocation of NHEKs were both suppressed by LXA4. CONCLUSION: Cell growth and inflammatory cytokine/chemokine production of NHEKs were inhibited by LXA4, and the inhibitory effects might be associated with the mechanisms of cyclin D1/P16INK4A, ERK1/2 and NF-κB signal transduction pathway.