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Background: To study the epidemiological characteristics of atypical Kashin–Beck disease cases without characteristic hand lesions such as interphalangeal joint enlargement and brachydactyly and the characteristics of ankle joint lesions. Methods: We investigated Kashin–Beck in the endemic villages in Heilongjiang Province. The patients were judged according to the "Diagnosis of Kashin–Beck Disease" (WS/T 207–2010). The severity of foot lesions was judged based on the changes of X-ray images. Residents of non-Kashin–Beck disease area were selected as normal controls in Jilin Province. Results: A total of 119 residents over 40 years old were surveyed in a natural village in the non-endemic area. A total of 1190 residents over 40 years old were surveyed in 38 endemic areas of Kashin–Beck disease. A total of 710 patients with Kashin–Beck disease were detected, including 245 patients with grade I, 175 patients with grade II, 25 patients with grade III, and 265 atypical patients. Among all investigated patients, 92.0% (653/710) had ankle joint changes, and it was 80.0% (196/245) in grade I patients and 95.4% (167/175) in grade II. Varying degrees of ankle joint changes were found in both grade III and atypical patients. The grade of Kashin–Beck disease was correlated with the degree of ankle joint change (P < 0.001), and the correlation coefficient rs = 0.376. Atypical Kashin–Beck disease patients in mild and severe endemic area of Kashin–Beck disease were younger than those with typical Kashin–Beck disease. Conclusions: We found a correlation between the degree of ankle joint change and the grade of Kashin–Beck disease. The higher the grade of Kashin–Beck disease, the more serious the change of the ankle joint. [ABSTRACT FROM AUTHOR]

We describe a new species, Blattisocius trifuricpilussp. nov., collected from polypore fungi on dead trees from Mengla County, Xishuangbanna, Yunnan Province, China. The new species can be distinguished from other species of the genus by the presence of 36 pairs of setae on the dorsal shield, of which 20 pairs of setae (j1, j3, z3, z4, z6, s3-s6, r3, Z1-Z5, S1-S5) are relatively stout and trifurcate, opisthogastric setae JV5 relatively stout and trifurcate, and the peritreme reaching anteriorly to level of j2. A key is presented to the seven recognizable Chinese species of the genus Blattisocius. [ABSTRACT FROM AUTHOR]

Objective To evaluate brain plasticity by resting-state fMRI (rs-fMRI), and to explore the potential neuroendocrine mechanism of repetitive transcranial magnetic stimulation (rTMS) in improving post-stroke cognitive impairment (PSCI) in patients with low thyroid hormone (TH) level. Methods A total of 28 patients with PSCI with low TH level who received rehabilitation treatment in Shijiazhuang People's Hospital from August 2020 to December 2021 were randomly divided into rTMS group (n = 15) and control group (n = 13). Cognitive function was assessed by Montreal Cognitive Scale (MoCA) before and 4 weeks after rTMS, and serum levels of tri-iodothyronine (T3), thyroxine (T4) and thyroid stimulating hormone (TSH) were measured by double antibody sandwich method. rs - fMRI was used to calculate the fractional amplitude of low - frequency fluctuation (fALFF) and observe the activated brain regions after stimulation. Pearson correlation analysis was used to obtain the distribution of synchronous changes of activated brain areas based on whole-brain functional connection strength of hypothalamus and serum TH level in 2 groups. Results After 4 weeks of intervention, compared with control group, MoCA score (F = 1163.054, P = 0.000), and serum T3 (F = 1111.685, P = 0.000), T4 (F = 847.333, P = 0.000), TSH (F = 251.316, P = 0.000) in rTMS group was increased. In rTMS group, fALFF value increased mainly in posterior cerebellar lobe (t = 4.699, P < 0.05), middle frontal gyrus (t = 4.356, P < 0.05) and superior frontal gyrus (t = 5.675, P < 0.05), while fALFF value decreased in superior temporal gyrus (t = -7.874, P <0.05) and middle temporal gyrus (t = - 5.776, P < 0.05). The enhanced functional connectivity of the whole brain with bilateral hypothalamus as the region of interest (ROI) and the simultaneous increase of serum T3 and TSH levels were mainly concentrated in the cerebellum, frontal lobe and parahippocampal gyrus. Conclusions rTMS can indirectly affect hypothalamic function through cerebral cortex, increase serum TH level and improve cognitive function in PSCI patients. [ABSTRACT FROM AUTHOR]

Pneumonia is one of the diseases that seriously endangers human health, and it is also the leading cause of death of children under the age of five in China. The most commonly used imaging examination method for radiologists is mainly based on chest X-ray images. Still, imaging errors often result during imaging examinations due to objective factors such as visual fatigue and lack of experience. Therefore, this paper proposes a feature fusion model, FC-VGG, based on the fusion of texture features (local binary pattern LBP and directional gradient histogram HOG) and depth features. The model improves model performance by adding detailed information in texture features to the convolutional neural network while making the model more suitable for clinical use. We input the X-ray image with texture features into the modified VGG16 model, C-VGG, and then add the Add fusion method to C-VGG for feature fusion so that FC-VGG is obtained, so FC-VGG has texture features detailed information and abstract information of deep features. Through experiments, our model has achieved 92.19% accuracy in recognizing children's pneumonia images, 93.44% average precision, 92.19% average recall, and 92.81% average F1 coefficient, and the model performance exceeds existing deep learning models and traditional feature recognition algorithms. [ABSTRACT FROM AUTHOR]

Loess tunnels are a common geo‐hazard in the Loess Plateau and not only cause considerable soil and water loss, but also aggravate and even induce the occurrence and development of other disasters such as ground fissures, mudflows, collapses, and landslides. To date, research on the hydrological characteristics and erosion behaviour of loess tunnel systems has focused on field investigation data and limited river basin observation data, whereas field test information and data are very scarce. In this study, field surveys, observations, field scouring experiments, and laboratory‐based sediment percentage tests were conducted to analyse the erosion characteristics, spatial distribution, and hydrological characteristics of a large‐scale loess tunnel system in the hilly Loess Plateau southeast region of northern China. The results showed that the loess tunnel erosion exhibited periodicity. Tunnel erosion in each period shows a similar erosion process, that is, thin‐layer water flow erosion and lateral expansion, tunnel wall collapse and deposit due to the loss of support from the lateral erosion, and erosion and transport of deposits by water flow. Waterfall erosion, lateral erosion, headward erosion, and the resulting collapses were the main forms of tunnel erosion. Besides this, the base level of erosion significantly affects the erosion characteristics of the loess tunnel. The hydrological characteristics during field scouring experiments exhibited three different stages: a lag effect, attributed to the temporary loss of water velocity in the first stage; small water flow fluctuations in the second stage; and an increase in total seepage loss with increased water injection flow in the third stage. The erosion rate was positively correlated with the flow quantity. The results of this study not only provide valuable reference data for research on the mechanism and velocity of erosion events in loess, but also provide a theoretical basis for the prevention of loess tunnel disasters in engineering construction. © 2020 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Chrysanthemum is widely grown throughout China, but there are large differences in quality, chemical composition and price among chrysanthemum from different origins, and similar appearance traits make it difficult to distinguish chrysanthemum. In this study, laser-induced breakdown spectroscopy (LIBS) technology combined with chemometrics was successfully used to classify chrysanthemum from nine different geographical sources. Different data processing methods and feature variable selection methods were evaluated, and the first derivative combined with the least absolute shrinkage and selection operator algorithm (1st Der-LASSO) was finally selected as the best processing method. The good classification performance was obtained using linear discriminant analysis (LDA), K-nearest neighbors (KNN), multi-layer perceptron (MLP) and random forest (RF) models with prediction accuracies of 100.0%, 99.0%, 96.5%, 99.4% for the validation set, respectively. For the independent test set, the established LASSO-LDA model can achieve 85.9% prediction accuracy. Furthermore, according to the importance of variables calculated by the RF model, Fe was the most important element to distinguish chrysanthemum from different origins, and the order of importance of other elements was O, Ca, Cu, K, Cl, B, Mg, Na. The combination of LIBS and chemometrics provides a simple, fast and reliable method for the geographic origin classification of chrysanthemum samples. This study provides a new basis for the application of LIBS technology in origin identification in the food field. [Display omitted] • Rapid identification of chrysanthemums from different origins using LIBS. • GirdSearchCV and data preprocessing improved the prediction performance. • Variable filtering methods reduced variables and improved the interpretability. • The importance of different elements for the origin identification was analyzed. • The 1st Der-LASSO-LDA model achieved 85.9% prediction accuracy for the test set. [ABSTRACT FROM AUTHOR]

Emissions of biogenic volatile organic compounds (BVOC) were measured using a relaxed eddy accumulation (REA) technique on an above-canopy tower in a temperate forest (Changbai Mountain, Jilin province, China) during the 2010 and 2011 summer seasons. Solar global radiation and photosynthetically active radiation (PAR) were also measured. Based on PAR energy dynamic balance, an empirical BVOC emission and PAR transfer model was developed that includes the processes of BVOC emissions and PAR transfer above the canopy level, including PAR absorption and consumption, and scattering by gases, liquids, and particles (GLPs). Simulated emissions of isoprene and monoterpenes were in agreement with observations. The averages of the relative estimator biases for the flux were 39.3 % for isoprene, and 27.1 % for monoterpenes in the 2010 and 2011 growing seasons, with NMSE (normalized mean square error) values of 0.133 and 0.101, respectively. The observed and simulated mean diurnal variations of isoprene and monoterpenes in the 2010 and 2011 growing seasons were evaluated for the validation of the empirical model. Under observed atmospheric conditions, the sensitivity analysis showed that emissions of isoprene and monoterpenes were more sensitive to changes in PAR than to water vapor content or to the magnitude of the scattering factor. The emissions of isoprene and monoterpenes in the 2010 and 2011 growing seasons (from June to September) were estimated using this empirical model along with hourly observational data, with mean hourly emissions of 1.71 and 1.55 mg m h for isoprene, and 0.48 and 0.47 mg m h for monoterpenes in 2010 and 2011, respectively. As formaldehyde (HCHO) is considered as the main oxidation product of isoprene and monoterpenes, it is necessary to investigate the link between HCHO and BVOC emissions. GOME-2 HCHO vertical column densities (VCDs) can be used to estimate BVOC emission fluxes in the Changbai Mountain temperate forest. [ABSTRACT FROM AUTHOR]

Abstract: The Beiyingxigou quartz vein and alteration type Pb–Zn–Ag deposit forms part of the metallogenic region southwest of the Mapeng batholith in the Central North China Craton. The quartz vein-type polymetallic deposit is associated with intermediate-felsic intrusives emplaced with Mesoarchean metamorphic basement. The mineralization is dominantly controlled by N–S and NW–SE trending faults. We identify four distinct stages of mineralization associated with the hydrothermal activity: pyrite phyllic stage, quartz–pyrite stage, quartz–polymetallic sulfide stage, and quartz–carbonate stage. Among these, the first two stages and the quartz–polymetallic sulfide stage represent the early and main metallogenic stages, respectively. Here we present results from integrated stable isotope studies (S, Pb, He–Ar and H–O) to deduce the possible sources of the mineralizing fluids and metals. The δ34S values recorded in the sulfide minerals of the early and main metallogenic stages show ranges of +0.4‰ to +2.2‰, and −11.4‰ to −6.8‰, respectively. The data illustrate two distinct pulses of hydrothermal fluids with δ34S mean values of 1.1‰ and −8.7‰. The S isotopes of pyrite and galena, sphalerite from the early and main metallogenic stages suggest a mixed source from the Mesozoic magmatism and the Precambrian basement. We infer that the slow cooling magma at the main metallogenic stage led to a larger interaction with the country rocks and resultant contamination, as compared to the early–middle metallogenic stage. The lead isotopic composition of pyrite, galena and sphalerite from the early to main stages shows restricted ranges with 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb ratios of 15.720–16.275, 15.068–15.140 and 38.688–41.316, respectively. The data are all characterized by lower crustal nature, suggesting the contribution of Pb from both the Mesozoic intrusions and the basement rocks in the region. The 3He/4He and 40Ar/36Ar ratios of fluid inclusions from the Beiyinxigou Pb–Zn–Ag deposit show a range of 0.01–0.23 Ra and 270.2–298.1, respectively. The 4He and 40Ar concentrations vary from 26.6 to 340.6 (10−7 cm3 STP/g) and 165.6 to 357.9 (10−7 cm3 STP/g), respectively, suggesting dominantly crustal contribution. The δ18OQ values of quartz and the δ18Dw values show ranges of 10.9‰ to 13.6‰ and −85.2‰ to −57.8‰, respectively. The calculated δ18OW values of the mineralizing fluids show a range of 3.7‰ to 7.5‰. Our data suggest that the hydrothermal fluids were a mixture of both magmatic and meteoric water. The results presented in this study link the Beiyinxigou Pb–Zn–Ag deposit to metallogeny associated with Mesozoic magmatism in the North China Craton. [Copyright &y& Elsevier]

• A novel approach reveal of the failure mechanism of slopes in tunnel environment. • The failure process is divided into five stages based on failure characteristics. • Tunnel is an important inducement of loess slope failure in tunnel environment. As a unique geological hazard, the occurrence of loess tunnels is closely related to slope failures. However, almost no research on the relationship between loess slope failures and tunnel erosions has been presented, which seriously restricts the deep understanding of the genesis mechanism and evolution process of loess slope failures. This paper focuses on revealing the failure mechanism of loess slopes in tunnel environments via methods including field investigation, exploration, field water injection tests, tracking tests and numerical simulations. The results show that the whole process of permeability coefficient of the soil layer in the test site is divided into three stages: the rapidly decreasing stage, the slowly decreasing stage and then the stable stage; the slope failure process is divided into five stages based on different failure characteristics: the soaking and softening stage, the erosion connecting stage, the slope local failure stage, the slump failure stage and the resting stage. Seepage has a great influence on loess slope failures in the tunnel environment, and it is as an important inducement of failure, while tunnels themselves play an aggravating catalytic role. The soil water interaction is shown to be an important internal cause of slope failure both by field tests and numerical simulations. The existence of tunnels is not conducive to the overall stability of the slope as tunnels expand the influence range of the soil-water interactions. This study re-evaluates the failure mechanism of loess slopes from a novel perspective based on the tunnel erosion environment. [ABSTRACT FROM AUTHOR]

Based on morphological and genetic data, we describe a new species of Tropidophorus from the tropical karst landscape in southeastern Yunnan Province, China, close to the Vietnam border. Phylogenetically, the new species forms a clade with T. baviensis, T. murphyi, and T. hainanus, with p-distances ranging from 4.7-5.1% for the 16S gene and 3.9-6.8% for 12S gene. Morphologically, the new species shares the karst morphotype of Tropidophorus, particularly similar as T. murphyi and T. baviensis, in which all having a dorsally compressed head and body, smooth dorsal head scales, and distinctively keeled body scales. However, the new species can be distinguished from these similar species by numbers of supralabial scales, ventral scales, scales around the tail at the10th subcaudal, and a larger body size. We emphasize the urgency of conservation for the tropical karst landscape in northern Indochina.

As precursors of photochemical secondary pollutants, oxygenated volatile organic compounds (OVOCs) play an important role in atmospheric photochemistry. In this study, 23 OVOCs were monitored using a commercial proton transfer reaction time-of-flight mass spectrometer at an urban site in Shenzhen, China. During the campaign, the mean total concentration of OVOCs was 23.3 ± 15.5 ppb (mean ± standard deviation), with a total ozone formation potential (TOFP) of 87.3 ± 58.7 ppb. Aldehydes contributed the most to the concentration and TOFP of OVOCs, followed by ketones, alcohols, and carboxylic acids. Formaldehyde, acetone, and acetaldehyde were the three most abundant atmospheric carbonyls. An optimized photochemical age-based parameterization method was locally applied for the source apportionment of OVOCs. OVOCs in Shenzhen primarily originated from biogenic sources during the summer. Secondary anthropogenic sources were also important contributors of most carbonyl compounds. The campaign was divided into four periods. Two periods were dominated by the east wind from the relatively clean coastal areas, with the mean concentration of anthropogenic OVOCs largely decreasing during the Chinese National Day holidays. The other two periods were dominated by northwest wind and northeast wind, respectively, with larger OVOC contributions from anthropogenic sources, suggesting that pollution transport from the inland was a main contributor to OVOCs. This study highlights the important contributions of both local and regional OVOC sources in urban atmospheres., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Melophagus ovinus is a hematophagous insect that is distributed worldwide and plays a crucial role in transmitting disease-causing pathogens. From June 2021 to March 2022, a total of 370 M. ovinus were collected from 11 sampling points in southern Xinjiang, China. The specimens were identified using morphological and molecular analyses. Rickettsia spp. and Anaplasma ovis were detected from all the samples using seven Rickettsia-specific genetic markers and the msp-4 gene of A. ovis. Approximately 11% of the M. ovinus specimens were positive for Rickettsia spp., and Candidatus Rickettsia barbariae was the most predominant species (35/41; 85.4%), while R. massiliae was least prevalent (6/41; 14.6%). Approximately 10.5% (39/370) of the M. ovinus specimens were positive for A. ovis of genotype III, which was co-detected with Candidatus R. barbariae in M. ovinus (3/370; 0.8%). To the best of our knowledge, this is the first report of the detection of R. massiliae and Candidatus R. barbariae in M. ovinus globally. The detection and control of insect-borne diseases originating from M. ovinus should be strengthened in southern Xinjiang, an area important to animal husbandry and production., (© 2023 The Authors. Medical and Veterinary Entomology published by John Wiley & Sons Ltd on behalf of Royal Entomological Society.)

Microplastics (MPs) are emerging pollutants that are enriched in sludge. They enter soil through sludge soil amendment, landfill, and discard, which will cause inescapable environmental pollution risks. Sludge treatment technology commonly used in China include anaerobic digestion (AD), thermal drying (TD), thermal hydrolysis (TH) and aerobic composting (AC). In this study, characteristics of MPs in sewage sludge from four representative large cities in China (Zhengzhou, Chongqing, Guangzhou, and Guilin) were analyzed. Effects of four representative sludge treatment technology on sludge MPs were also studied. In addition, the amount of MPs input to soil from sludge in China was estimated. The abundance range of sludge MPs of representative cities in China was 1448-11,125 n∙kg -1 DW. Previous studies indicate that this abundance range is low among other domestic cities and is close to that of European countries. MPs were predominantly fiber-shaped, accounting for 46.66%; 56.5% MPs were white and transparent, and 62.5% were polypropylene and polyethylene. The abundance of MPs in the sludge increased after TH, indicating that MPs broke into smaller particles. However, the other three treatment methods had no significant influence on the abundance of MPs. Scanning electron microscopy analysis showed that the micro-morphology of sludge MPs surface were rougher after AD, and MPs cracked following TD and TH. Furthermore, broken edges were more blurred after TH, and surfaces of MPs were damaged and eroded after AC. The input quantities of MPs in sludge to soil was deduced to be 10 13 particles per year. These results are important for controlling the potential risk of sludge MPs in China., Competing Interests: Declaration of competing interest The authors declare no conflicts of interest., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Background: The association between high-sensitivity C-reactive protein (hsCRP) levels and all-cause mortality for the oldest-old (aged 80 years or older) remains unclear. We aimed to investigate the associations between hsCRP concentrations and the risks of all-cause mortality, and further identify the potential modifying factors affecting these associations among the oldest-old., Methods: This prospective, community-based cohort study included 2,206 participants aged 80 years or older (median age 93.0 years) from the Healthy Aging and Biomarkers Cohort Study. Cox proportional hazards regression models were used to estimate hazard ratios (HRs) with 95% confidential intervals (95% CIs) for all-cause mortality according to hsCRP quartiles and recommendation for relative risk categories of hsCRP levels (< 1.0, 1.0-3.0, and > 3.0 mg/L), with adjustment for sociodemographic information, lifestyle, physical examination, medical history, and other potential confounders., Results: During a median follow-up period of 3.1 years (IQR: 1.6-3.9 years), 1,106 deaths were verified. After full adjustment for potential confounders, a higher hsCRP concentration was positively associated with an increased risk of all-cause mortality ( P for trend < 0.001). Compared with the lowest quartile, the fully adjusted HRs of the second, third, and fourth quartiles were 1.17 (95% CI: 0.94, 1.46), 1.28 (95% CI: 1.01, 1.61), and 1.49 (95% CI: 1.20, 1.87), respectively. The association of hsCRP with all-cause mortality was modified by smoking status ( P for interaction = 0.011), an increased risk of hsCRP with all-cause mortality showed among non-current smokers (HR: 1.17; 95% CI: 1.07, 1.28), but no significance was observed in current smokers (HR: 0.83; 95% CI: 0.66, 1.18)., Conclusions: Our study indicated that elevated hsCRP concentrations were associated with a higher risk of all-cause mortality among Chinese oldest-old. Future studies investigating additional factors of disease and aging processes are needed to obtain a better understanding of the mechanisms., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Chen, Li, Yang, Cao, Cheng, Zhao, Zhang, Lv, Li, Zhou, Li, Qu, Yin, Liu, Wu, Shi and Mao.)

Antibiotic resistance genes (ARGs) raise public concern as emerging contaminants. The abundance and variation of 11 ARGs, intI1 and 16S rRNA gene were deciphered using quantitative PCR (qPCR) in two drinking water treatment systems that include river, wetland, drinking water treatment plants (DWTPs) and tap water from the Yangtze River Delta. The influencing factors for ARG abundance in river water were also explored. All investigated genes were detected in river water and there was no significant difference between the two systems, with sulfonamide ARGs occupying the highest abundance. Temperature had a significant effect on the ARG distribution based on permutational multivariate analysis of variance (PERMANOVA). Further Spearman analysis demonstrated that temperature was strongly correlated with the abundance of sul1, sul2, tetA and tetC, and these genes were significantly correlated with environmental factors (including temperature, total organic carbon (TOC) and dissolved oxygen (DO)). Considering the frequency and abundance of ARGs, as well as their correlation with other genes, sul1, sul2, tetA and tetC could be used as indicators of ARGs in river water. No significant reduction was noted for the absolute abundance of ARGs from river water to wetland water. Principle coordinates analysis (PCoA) combined with PERMANOVA revealed that drinking water treatment was responsible for reducing 16S rRNA gene and ARG abundance resulting in 3-log reductions. However, it should be noted that after transportation of distribution pipeline, both 16S rRNA gene and ARGs still detected in tap water, which indicated persistence of ARGs and will require further research., Competing Interests: Declaration of competing interest We declare that we have no financial and personal relationships with other people or organizations that can inappropriately influence our work., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Online forums in Chinese universities play an important role in understanding collective behavior of college students. Of particular interest are community and popularity. We address these two issues by examining data from Bulletin Board Systems (BBSs) of four Chinese universities. To characterize users' behavior, we introduce a hypothesis test to infer individual preferred boards, which yields a polarization of users. We also perform a multilevel algorithm to detect communities of each BBS network. We measure the similarity between the board-preferred polarization and the algorithmically identified community structure by quantitative and visual tools. The resulting discrepancy indicates that board labels are inadequate to represent underlying communities. To reveal online popularity, we employ latent Dirichlet allocation to mine topics from threads to compare popularity in different universities. Based on which, we implement the Cox-Stuart test to explore the change in popularity over time and reproduce significantly ascending and descending topics around a decade. Finally, we devise a two-step model based on users' preference and interests to reproduce the observed connectivity patterns., Competing Interests: The authors have declared that no competing interests exist.

BACKGROUND Acinetobacter baumannii is an important nosocomial pathogen which shows a high level of mortality risk. Several papers have reported biofilm formation as a well-known pathogenic mechanism in A. baumannii infections and exceptional antibiotic resistance. The study aims to explore the potential relationships between biofilm-related genes and antimicrobial resistance. MATERIAL AND METHODS Samples from 122 patients with lower respiratory tract infections of A. baumannii were collected at Fujian Longyan First Hospital from January 2013 to September 2014. A. baumannii was isolated from sputum specimens. Biofilm-related genes including abaI, csuE, ompA, and bla-PER1 were analyzed by PCR. The minimum inhibitory concentration method was used to determine the sensitivity of each strain to antibiotics. RESULTS The clinical manifestations of A. baumannii-induced lower respiratory tract infections lacked specificity. Infected patients were most commonly admitted to intensive care units (54.9%) and frequently had chronic obstructive pulmonary disease (27.0%). The detection rates of abaI and csuE were both 59.8%, and those of ompA and bla-PER1 were 100% and 0%, respectively. After genetic testing, antimicrobial resistance to amikacin, ampicillin/sulbactam, and 14 other types of antimicrobials was higher in abaI- and csuE-positive strains than in abaI- and csuE-negative strains (P<0.05). CONCLUSIONS The findings of our study suggest that abaI- and csuE-positive Acinetobacter baumannii strains are associated with a higher incidence of antibiotic resistance in 14 types of antimicrobials.

Nitrous acid, HNO2, is an important precursor of OH radicals in the troposphere. Measurements of HNO2 and NO2, using differential optical absorption spectroscopy (DOAS), were performed in Shanghai, China for a period from October 22, 2004 to January 4, 2005. The mean (and median) hourly concentrations of HNO2 and NO2 during this period were 1.1 (0.7) ppb and 24 (21.4) ppb respectively. A correlation between HNO2/NO2 and PMI,( mass concentrations was obtained. This correlation suggests that significant heterogeneous chemical production of HNO2 may occur through NO2 reactions on aerosol surfaces. This hypothesis was further supported by detailed analysis of selected pollution episodes in this study. At the same time, the water dependence of HNO2 formation was studied by analysis of relative humidity (RH). It showed that the maximum HNO2/NO2 ratio was increased along with RH below 70% and inhibited at RH>70%.