A rapid visualization method for detecting rotavirus A by combining nuclear acid sequence-based amplification with the CRISPR-Cas12a assay.

Introduction. Rotavirus A is the most common pathogen causing diarrhoea in children less than 5 years, leading to severe complications such as dehydration, electrolyte imbalances, acidosis, myocarditis, convulsions, pneumonia, and other life-threatening conditions.Gap statement. There is an urgent need for a rapid and efficient nucleic acid detection strategy to enable early diagnosis and treatment, preventing rotavirus transmission and associated complications.Aim. This article aimed to develop a nuclear acid sequence-based amplification (NASBA)-Cas12a system for detecting rotavirus A using fluorescence intensity or lateral flow strips.Methodology. The NASBA technology was combined with the clustered regularly interspaced short palindromic repeats-Cas12a system to establish a NASBA-Cas12a system for detecting rotavirus A.Results. The NASBA-Cas12a system could detect rotavirus A at 37 ℃ within 70 min and had no cross-reactivity with other viruses, achieving a limit of detection of 1.2 copies µl-1. This system demonstrated a sensitivity of 100%, specificity of 90%, positive predictive value of 97.22% and negative predictive value of 100%. The kappa value was 0.933, indicating that the NASBA-Cas12a system was highly consistent with reverse transcription-PCR.Conclusion. The NASBA-Cas12a system exhibited high sensitivity and specificity for detecting rotavirus A, showing great potential for clinical application.

Effects of different forms of amino acid supplementation on the performance and intestinal barrier function of laying hens fed a low-protein diet.

The aim of this study was to investigate the effects of low-protein diets and the sustained release of synthetic amino acids (AA) on the performance, intestinal barrier function and nitrogen excretion of laying hens. Two hundred eighty-eight 39-week-old Hyline brown laying hens of were randomly divided into 3 groups with 8 replicates per group. The crude protein level in the control group (CON) was 16%, the crude protein levels in the crystal AA supplement group (LCP-CAA) and microencapsulated AA group (LCP-MAA) were both 13%, and the AA levels in the LCP-CAA and LCP-MAA groups were consistent with that in the CON group. The experiment lasted 12 wk, and production performance was assessed weekly. The FCR and ADFI values were significantly greater for the LCP-CAA group than for the CON and LCP-MAA groups (P < 0.05). Two hours after feeding, His levels were significantly greater in the LCP-CAA group than in the LCP-MAA group (P < 0.05); 4 h after feeding, the contents of Met, Thr, Leu and Val were significantly greater in blood from the LCP-MAA group (P < 0.05); 6 h after feeding, Trp, Ile and Arg levels were significantly greater in the LCP-MAA group (P < 0.05). The chylase content significantly decreased in the duodenum of the LCP-CAA group (P < 0.05), and the chylase and trypsin were contents increased in the ileum of the LCP-MAA group (P < 0.05). In the LCP-MAA group, significantly increased mRNA expression levels of Occludin, ZO-1 in duodenum; Occludin, ZO-1, y+LAT1 in jejunum; and ZO-1 in ileum were detected at 8 and 12 weeks (P < 0.05). The fecal nitrogen content significantly decreased in the low protein diet group (P < 0.01). In conclusion, reducing dietary crude protein levels and supplementing with microencapsulated AAs can improve intestinal barrier function, promote digestive enzyme secretion, increase the expression of AA transporters, improve dietary protein utilization efficiency, and reduce nitrogen emission in laying hens.

[Characteristics and clinical value of intestinal metabolites in children aged 4-6 years with obstructive sleep apnea-hypopnea syndrome]. / 4~6å²é˜»å¡žæ€§ç¡çœ å‘¼å¸æš‚åœä½Žé€šæ°”ç»¼åˆå¾æ‚£å„¿è‚ é“ä»£è°¢äº§ç‰©ç‰¹å¾åŠä¸´åºŠä»·å€¼åˆ†æž.

OBJECTIVES: To study the characteristics and clinical value of intestinal metabolites in children aged 4-6 years with obstructive sleep apnea-hypopnea syndrome (OSAHS). METHODS: A total of 31 children aged 4-6 years with OSAHS were prospectively enrolled as the test group, and 24 healthy children aged 4-6 years were included as the control group. Relevant clinical indicators were recorded. Fecal samples were collected, and non-targeted metabolomics analysis using liquid chromatography-mass spectrometry was performed to detect all metabolites. RESULTS: A total of 206 metabolites were detected, mainly amino acids and their derivatives. There was a significant difference in the overall composition of intestinal metabolites between the test and control groups (P<0.05). Eighteen different metabolites were selected, among which six (N-acetylmethionine, L-methionine, L-lysine, DL-phenylalanine, L-tyrosine, and L-isoleucine) had receiver operating characteristic curve areas greater than 0.7 for diagnosing OSAHS. Among them, N-acetylmethionine had the largest area under the curve, which was 0.807, with a sensitivity of 70.83% and a specificity of 80.65%. Correlation analysis between different metabolites and clinical indicators showed that there were positive correlations between the degree of tonsil enlargement and enterolactone, between uric acid and phenylacetaldehyde, between blood glucose and acetylmethionine, and between cholesterol and 9-bromodiphenyl and procaine (P<0.05). There were negative correlations between the degree of tonsil enlargement and N-methyltyramine, aspartate aminotransferase and indolepropionic acid and L-isoleucine, between alanine aminotransferase and DL-phenylalanine, between indolepropionic acid and L-isoleucine, between uric acid and hydroxyquinoline, and between urea nitrogen and N,N-dicyclohexylurea (P<0.05). The metabolic functional pathways affected by differential metabolites mainly included riboflavin metabolism, arginine and proline metabolism, pantothenic acid and coenzyme A biosynthesis, cysteine and methionine metabolism, lysine degradation and glutathione metabolism. CONCLUSIONS: Intestinal metabolites and metabolic functions are altered in children aged 4-6 years with OSAHS, primarily involving amino acid metabolism disorders. The screened differential intestinal metabolites have potential screening and diagnostic value as biomarkers for OSAHS.

Composition and dynamics of intestinal fungi during the postnatal 2 months of very low birth weight infants.

It has been found that intestinal fungi play a role in the composition of the intestinal microecology and in the formation and development of the immunity during childhood. We investigated the gut fungi composition of preterm infants to analysis composition and dynamics of intestinal fungi during the postnatal 2 months of very low birth weight infants. We collected feces from 34 very low birth weight infants (VLBWI) and 28 preterm infants with birth weight >1500 g. We extracted total fungal DNA from feces and analyzed the composition of gut fungus through ITS sequencing. The fungal detectable rate in the experimental group peaked on day 3 (85.19%), then gradually decreased and started to show an increasing trend again by day 28. There were significant differences in the alpha diversity of intestinal fungus between VLBWI and controls, and the VLBWI had its own characteristics at different time points in richness and diversity. A total of 10 phylums and 342 genera were identified in all VLBWI samples. The dominant fungal phylum of the VLBWI group is Ascomycota (50.3%)and Basidiomycota (48.8%). The functional metabolic activity of the experimental group was lower than that of the control group. CONCLUSION: The composition and abundance of VLBWI intestinal fungal showed several alterations during the first 2 months of life. The prediction of gut microbiota function suggests that intestinal metabolic function may be altered in VLBWI. WHAT IS KNOWN: • A limited number of studies has been found that symbiont fungi may be able to calibrate host immunological responses, promote development of peripheral lymphoid organs, promote T cell responses, and even may be associated with the development of certain diseases, such as inflammatory bowel disease (IBD), NEC, and allergic diseases. However, previous studies on intestinal microecology have mainly focused on adults while neglecting the role of fungi in the gut of children due to the much lower abundance of intestinal fungi than bacteria, limitations of techniques for detecting fungi, the difficulty of obtaining samples, and the absence of largescale reference databases. WHAT IS NEW: • In recent years, the discovery and development of fungal detection technologies such as 18s rDNA sequencing technology, Internal Transcribed Spacer(ITS), and DNA fingerprinting technology have further broadened the perspective on the impact of intestinal fungal exposure in early life.

Changes in Gut Microbiota at 1-60 Days in 92 Preterm Infants in a Neonatal Intensive Care Unit Using 16S rRNA Gene Sequencing.

BACKGROUND Neonatal gut diversity is influenced by birth conditions and probiotic/antibiotic use. The gut microbiota affects brain development, immunity, and risk of diseases. Preterm infants, especially in neonatal intensive care units (NICUs), have different gut flora from full-term infants, suggesting in utero microbial colonization. This study examined gut microbiota changes in 92 NICU preterm infants in China. MATERIAL AND METHODS We collected data on 92 preterm infants admitted to the NICU immediately after birth, and fecal samples were collected on days 1, 3, 7, 14, 21, 28, and 60. We analyzed changes in intestinal bacteria through 16S rRNA sequencing, predicted the change in gut microbiota function over time, and compared the effects of main feeding modality on the intestinal bacteria of preterm infants. RESULTS At the phylum level, the top 5 phyla in total accounted for 99.69% of the abundance, in decreasing order of abundance: Proteobacteria, Firmicutes, Actinobacteria, Tenericutes, and Bacteroidetes. At the genus level, the top 10 genera in terms of abundance accounted for a total of 90.90%, in decreasing order of abundance: Pseudomonas, Staphylococcus, Klebsiella, Escherichia-Shigella, unclassified Enterobacteriaceae, Staphylococcus, Clostridium-sensu-stricto-1, Streptococcus, Sphingomonas, and Ureaplasma. The abundance of Proteobacteria and Pseudomonas showed a decreasing trend at first, reached a minimum at day 14, and then an increasing trend, while the opposite trend was observed for Firmicutes. The metabolic function of the bacterial community changed greatly at different time points. The abundance of Proteobacteria at the phylum level and Streptococcus at the genus level in formula-fed infants were significantly higher than in breast-fed infants. CONCLUSIONS Between 1 and 60 days, the gut microbiome in preterm infants in the NICU changed with changes in feeding patterns, with the main gut bacteria being from the phyla, Proteobacteria, and Pseudomonas.

H3K27me3 of Rnf19a promotes neuroinflammatory response during Japanese encephalitis virus infection.

Histone methylation is an important epigenetic modification that affects various biological processes, including the inflammatory response. In this study, we found that infection with Japanese encephalitis virus (JEV) leads to an increase in H3K27me3 in BV2 microglial cell line, primary mouse microglia and mouse brain. Inhibition of H3K27me3 modification through EZH2 knockdown and treatment with EZH2 inhibitor significantly reduces the production of pro-inflammatory cytokines during JEV infection, which suggests that H3K27me3 modification plays a crucial role in the neuroinflammatory response caused by JEV infection. The chromatin immunoprecipitation-sequencing (ChIP-sequencing) assay revealed an increase in H3K27me3 modification of E3 ubiquitin ligases Rnf19a following JEV infection, which leads to downregulation of Rnf19a expression. Furthermore, the results showed that Rnf19a negatively regulates the neuroinflammatory response induced by JEV. This is achieved through the degradation of RIG-I by mediating its ubiquitination. In conclusion, our findings reveal a novel mechanism by which JEV triggers extensive neuroinflammation from an epigenetic perspective.

Plasma tRF-16-79MP9PD and tRF-28-OB1690PQR304 as potential biomarkers for 4- to 7-year-old children with obstructive sleep apnea-hypopnea syndrome.

Background: We investigated the expression and the potential value of plasma transfer RNA-derived fragments (tRFs) of children with obstructive sleep apnea-hypopnea syndrome (OSAHS) as screening biomarkers. Methods: At first, we randomly selected five plasma samples from the case group and the control group for high-throughput RNA sequencing. Secondly, we screened two tRFs with different expression between the two groups, amplified it by quantitative reverse transcription-PCR (qRT-PCR) on all samples. Then we analyzed the diagnostic value of the tRFs and their correlation with the clinical data. Results: A total of 50 OSAHS children and 38 healthy controls were included. Our results demonstrated that the plasma levels of tRF-16-79MP9PD and tRF-28-OB1690PQR304 were significantly down-regulated in OSAHS children. Receiver operating characteristic curve (ROC) showed that the area under the curve (AUC) of tRF-16-79MP9PD and tRF-28-OB1690PQR304 was 0.7945 and 0.8276. In addition, the AUC of the combination reached 0.8303 with 73.46% and 76.42% sensitivity and specificity. Correlation analysis showed that the degree of tonsil enlargement, hemoglobin (Hb) and triglyceride (TG). were related to the expression levels of tRF-16-79MP9PD and tRF-28-OB1690PQR304. Multivariable linear regression analysis showed that degree of tonsil enlargement, Hb and TG related to tRF-16-79MP9PD while degree of tonsil enlargement and Hb related to tRF-28-OB1690PQR304. Conclusions: The expression levels of tRF-16-79MP9PD and tRF-28-OB1690PQR304 in the plasma of OSAHS children decreased significantly which were closely related to the degree of tonsil enlargement, Hb and TG, may become novel biomarkers for the diagnosis of pediatric OSAHS.

[Recent progress in the biosynthesis of dicarboxylic acids, a monomer of biodegradable plastics].

Plastics are one of the most important polymers with huge global demand. However, the downsides of this polymer are that it is difficult to degrade, which causes huge pollution. The environmental-friendly bio-degradable plastics therefore could be an alternative and eventually fulfill the ever-growing demand from every aspect of the society. One of the building blocks of bio-degradable plastics is dicarboxylic acids, which have excellent biodegradability and numerous industrial applications. More importantly, dicarboxylic acid can be biologically synthesized. Herein, this review discusses the recent advance on the biosynthesis routes and metabolic engineering strategies of some of the typical dicarboxylic acids, in hope that it will help to provide inspiration to further efforts on the biosynthesis of dicarboxylic acids.

The potential of tRF-21-U0EZY9X1B plasmatic level as a biomarker of children with obstructive sleep apnea-hypopnea syndrome.

PURPOSE: We investigated changes in plasma transfer RNA related fragments (tRF) in children with obstructive sleep apnea-hypopnea syndrome (OSAHS) and the potential value as a disease marker. METHODS: Firstly, we randomly selected five plasma samples from the case group and the control group for high-throughput RNA sequencing. Secondly, we screened one tRF with different expression between the two groups, amplified it by quantitative reverse transcription-PCR (qRT-PCR) and sequenced the amplified product. After confirming that the qRT-PCR results were consistent with the sequencing results and the sequence of the amplified product contained the original sequence of the tRF, we performed qRT-PCR on all samples. Then we analyzed the diagnostic value of the tRF and its correlation with some clinical data. RESULTS: A total of 50 OSAHS children and 38 control children were included in this study. There were significant differences in height, serum creatinine (SCR) and total cholesterol (TC) between the two groups. The plasma expression levels of tRF-21-U0EZY9X1B (tRF-21) were significantly different between the two groups. Receiver operating characteristic curve (ROC) showed that it had valuable diagnostic index, with area under the curve (AUC) of 0.773, 86.71% and 63.16% sensitivity and specificity. CONCLUSIONS: The expression levels of tRF-21 in the plasma of OSAHS children decreased significantly which were closely related to hemoglobin, mean corpuscular hemoglobin, triglyceride and creatine kinase-MB, may become novel biomarkers for the diagnosis of pediatric OSAHS.

Plasma interleukin-41 serves as a potential diagnostic biomarker for Kawasaki disease.

INTRODUCTION: Kawasaki disease (KD) is a systemic vasculitis that causes abnormalities in the coronary arteries. Interleukin (IL)-41 is a novel immunoregulatory cytokine involved in the pathogenesis of some inflammatory and immune-related diseases. However, the role of IL-41 in KD is unclear. The purpose of this study was to detect the expression of IL-41 in the plasma of children with KD and its relationship with the disease. METHODS: A total of 44 children with KD and 37 healthy controls (HC) were recruited for this study. Plasma concentrations of IL-41 were determined by ELISA. Correlations between plasma IL-41 levels and KD-related clinical parameters were analyzed by Pearson correlation and multivariate linear regression analysis. Receiver operating characteristic curve analysis was used to assess the clinical value of IL-41 in the diagnosis of KD. RESULTS: Our results showed that plasma IL-41 levels were significantly elevated in children with KD compared with HC. Correlation analysis demonstrated that IL-41 levels were positively correlated with D-dimer and N-terminal pro-B-type natriuretic peptide, and negatively correlated with IgM, mean corpuscular hemoglobin concentration, total protein, albumin and pre-albumin. Multivariable linear regression analysis revealed that IgM and mean corpuscular hemoglobin concentrations were associated with IL-41. Receiver operating characteristic curve analysis showed that the area under the curve of IL-41 was 0.7101, with IL-41 providing 88.64 % sensitivity and 54.05 % specificity. CONCLUSION: Our study indicated that plasma IL-41 levels in children with KD were significantly higher than those in HC, and may provide a potential diagnostic biomarker for KD.

Gut microbiota dysbiosis in 4- to 6-year-old children with obstructive sleep apnea-hypopnea syndrome.

OBJECTIVE: Several experiments on animals have reported the relationship between obstructive sleep apnea-hypopnea syndrome (OSAHS) and gut microbiota. We investigated the gut microbiota composition of children aged 4-6 years with OSAHS to complement the pathogenesis and clinical screening methods of OSAHS. METHODS: We collected feces from 43 children with OSAHS and 45 controls aged 4-6 years. We extracted total bacterial DNA from feces and analyzed the composition of gut microbiota through 16S ribosomal RNA sequencing. RESULTS: There were significant differences in bacteria producing short-chain fatty acids (SCFAs) between OSAHS children and controls, including Faecalibacterium, Roseburia, and a member of Ruminococcaceae. A gut microbiota model for pediatric OSAHS screening showed that the receiver operating characteristic-area under the curve (ROC-AUC) was 0.794 with 79.1% and 80.0% sensitivity and specificity, respectively. Functional analysis of the gut microbiota revealed several alterations in metabolism. CONCLUSION: The composition of gut microbiota in OSAHS children is partially changed. The altered intestinal flora may provide a new screening method for the diagnosis of children with OSAHS. The prediction of gut microbiota function suggests that intestinal metabolic function may be altered in OSAHS children.

Dominant bacteria and influencing factors of early intestinal colonization in very low birth weight infants: A prospective cohort study.

BACKGROUND: The intestine of newborns is colonized by bacteria immediately after birth. This study explored dominant bacteria and influencing factors of early intestinal colonization in the early life of very low birth weight infants (VLBWI). METHODS: We enrolled 81 VLBWI and collected anal swabs at 24 h, 7th, 14th and 21st day after birth. We conducted bacterial culture for anal swabs, then selected the colony with obvious growth advantages in the plate for further culture and identification. Afterward, we analyzed the distribution and influencing factors of intestinal dominant microbiota combined with clinical data. RESULTS: A total of 300 specimens were collected, of which 62.67% (188/300) had obvious dominant bacteria, including 29.26% (55/188) Gram-positive bacteria and 70.74% (133/188) Gram-negative bacteria. The top five bacteria with the highest detection rates were Klebsiella pneumoniae, Escherichia coli, Enterococcus faecium, Enterococcus faecalis and Serratia marcescens. Meconium-stained amniotic fluid and chorioamnionitis were correlated with intestinal bacterial colonization within 24 h of birth. Mechanical ventilation and antibiotics were independent risk factors affecting colonization. Nosocomial infection of K. pneumoniae and S. marcescens were associated with intestinal colonization. The colonization rates of K. pneumoniae, E. coli, E. faecium, and E. faecalis increased with the birth time. CONCLUSIONS: The colonization rate in the early life of VLBWI increased over time and the predominant bacteria were Gram-negative bacteria. Meconium-stained amniotic fluid and chorioamnionitis affect intestinal colonization in early life. Mechanical ventilation and antibiotics were independent risk factors for intestinal bacterial colonization. The nosocomial infection of some bacteria was significantly related to intestinal colonization.

Antiproliferative effect and characterization of a novel antifungal peptide derived from human Chromogranin A.

CGA-N46 is a novel antifungal peptide derived from the N-terminus of human Chromogranin A, corresponding to the 31st to 76th amino acids. Further research on its activities and characteristics may be helpful for the application of CGA-N46 in medical or other situations. In the present study, the antifungal spectrum and physicochemical characteristics of CGA-N46 were investigated using an antifungal assay, its antiproliferative effects on cancer and normal cells were assessed using MTT assay and its combinatorial effect with other antibiotics was analyzed using checkerboard analysis. The results showed that CGA-N46 exhibited antifungal activity against the tested Candidas (C. glabrata, C. parapsilosis, C. krusei, C. tropicalis and C. albicans) at a concentration of <0.8 mM, but had no effect on the growth of filamentous fungi or other types of fungi (Cryptococcus neoformans, Aspergillus fumigatus, Aspergillus flavus, Aspergillus niger, Fusarium moniliforme, Microsporum canis, Microsporum gypseum, Trichophyton rubrum and Trichophyton mentagrophytes), even at a concentration of 3.2 mM. CGA-N46 had an inhibitory effect on the proliferation of lung cancer A549 cells and a reversible effect on the growth of normal primary chicken embryo fibroblast cells, but no hemolytic activity on human erythrocytes at the minimum inhibitory concentration of CGA-N46 against yeasts. The antifungal activity of CGA-N46 was stable at a temperature <40°C or within a broad pH range (pH 5.0-7.0). Its antifungal activity was enhanced when the peptide was used in combination with fluconazole and terbinafine. The present results indicate that CGA-N46 is a safe, physicochemically stable, antifungal peptide with anticancer cell activity that exhibits an additive effect with conventional antibiotics.

Anti-candidal activity of a novel peptide derived from human chromogranin A and its mechanism of action against Candida krusei.

Candida species (Candida spp.) are important fungal pathogens, which cause numerous clinical diseases associated with significant mortality and morbidity in healthcare settings. In our previous study, we identified a recombinant peptide, chromogranin A (CGA)-N46, corresponding to the N-terminal Pro31-Gln76 sequence of human CGA, that exhibited antifungal activity against Candida albicans. The present study investigated the antifungal activity of CGA-N46, and its underlying mechanism, against numerous Candida spp. CGA-N46 inhibited the growth of all of the tested Candida spp., of which Candida krusei exhibited the greatest sensitivity. CGA-N46 was able to disrupt the stability of the phospholipid monolayer without damaging the integrity and permeability of the outer membrane of C. krusei cells, and induced cytoplasm vacuolization and mitochondrial damage. In addition, treatment of C. krusei with CGA-N46 was associated with decreased levels of intracellular reactive oxygen species, a reduction in the mitochondrial membrane potential, and DNA synthesis inhibition. The results of the present study suggested that CGA-N46 was able to pass through the cell membrane of Candida spp. by temporarily destabilizing the phospholipid membrane, which in turn led to mitochondrial dysfunction and inhibition of DNA synthesis. Therefore, CGA-N46 may be considered a novel antifungal compound for the treatment of patients with C. krusei infections.

Rhodium(III)-catalyzed C-H activation/[4+3] annulation of N-phenoxyacetamides and α,ß-unsaturated aldehydes: an efficient route to 1,2-oxazepines at room temperature.

An efficient Rh(III)-catalyzed coupling reaction of N-phenoxyacetamides with α,ß-unsaturated aldehydes to give 1,2-oxazepines via C-H activation/[4+3] annulation has been developed. This transformation does not require oxidants and features C-C/C-N bond formation to yield seven-membered oxazepine rings at room temperature. Further derivation of 1,2-oxazepines leads to important chroman derivatives.

[Detection and clinicopathologic significance of microsatellite alteration and p53 mutation of neuroendocrine cells in colorectal adenocarcinoma].

OBJECTIVE: To study the possible clonal origin of neuroendocrine cells in colorectal adenocarcinoma. METHODS: Twenty-six microsatellite loci were screened using laser capture microdissection, DNA extraction and whole genome amplification. Microsatellite instability (MSI) and loss of heterozygosity (LOH) in adenocarcinoma cells and neuroendocrine cells amongst 30 cases of colorectal carcinoma with neuroendocrine differentiation were detected using polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP)-silver staining. The mutation status of p53 was evaluated by PCR-sequencing. The clonal origin of neuroendocrine cells in colorectal adenocarcinoma was determined. RESULTS: Amongst the 30 cases studied, the prevalence of MSI was 16.9% while that of LOH was 8.5%. The rate showed no statistically significant difference between adenocarcinoma cells and neuroendocrine cells. In 6 cases, the microsatellite alteration was entirely consistent. In 23 cases, the rate of microsatellite alteration consistency was greater than that of inconsistency. In 1 case, the consistency and inconsistency rates were identical. There was statistically significant difference between consistency and inconsistency of microsatellite alteration. The prevalence of p53 mutation was 16.7% which was the same for both adenocarcinoma cells and neuroendocrine cells. CONCLUSIONS: Adenocarcinoma cells and neuroendocrine cells in colorectal adenocarcinoma with neuroendocrine differentiation have similar biologic changes. It is likely that they are of identical origin.

[Distribution of heavy metals in PM10 and its release in the simulated acid rain].

The distribution of heavy metals in inhalable particulate matter (PM10), which were collected in Foshan during December of 2004, was characterized by scanning electron microscope-X-ray energy dispersive analysis technique (SEM-EDS) and inductively coupled plasma-atomic emission spectroscopy (ICP-AES). The releases of Cu, Pb, Zn and Cd were also examined for their potential releases in simulated acid rain, which were quantified with batch reactors. The results showed that the daily average concentration of PM10 was 0.19 mg/m(3), about 79% higher than the secondary standard of China. The relatively contents of Zn and Pb in PM10 were much higher than Cd and Zn, whereas the releasing rates of Cd and Zn in simulated acid rain were greater than that of Cu and Pb. The releasing rates of heavy metals from PM10 were increased as the pH of the acid rain decreased.