Search

[Objectives] The paper was to investigate the protective effect of Fufang Yatongding on experimental periodontitis in rats. [Methods] Experimental periodontitis rats were randomly divided into blank group (5 rats), model group, control group and experimental group, with 8 rats in each group. The rats in the blank group were fed with normal diet, and those in the model group, control group and experimental group were administered intragastrically with normal saline, minocycline hydrochloride solution and Fufang Yatongding solution, respectively. After4 weeks, alveolar bone resorption was measured. Serum matrix metalloproteinases (MMPs) and inflammatory factors were detected by ELISA, and the changes in gingival tissue were observed by HE staining. [Results] Compared with the control group, the distance from enamel cementum to alveolar crest in the experimental group was decreased (P <0.05). Compared with the control group, the levels of serum MMPs and inflammatory factors in the experimental group were decreased (P <0.05). The results of HE staining showed that the cells in the gingival tissue of rats in the blank group were normal in morphology and intact in structure, and the cells in the gingival tissue of rats in the model group were damaged and out of order, while the cells in the control group were slightly intact and arranged orderly, and the pathological damage of rats in the experimental group was less than that in the control group. [ Conclusions] Fufang Yatongding has protective effect on experimental periodontitis in rats by inhibiting the release of MMPs and inflammatory factors. [ABSTRACT FROM AUTHOR]

Data-driven approaches have achieved remarkable success in different applications, however, their use in solving PDE has only recently emerged. Herein, we present the potential fluid method, which uses existing data to nest physical meanings into mathematical iterative processes. Potential fluid method is suitable for PDE, such as CFD problems, including Burgers' equation. Potential fluid method can iteratively determine the steady-state space distribution of PDE. For mathematical reasons, we compare the potential fluid method with the finite difference method and give a detailed explanation. [ABSTRACT FROM AUTHOR]

The pseudo resistor (PR) is widely used in integrated circuits. It comprises two transistors back-to-back to force them into the sub-threshold region, which provides large resistance with a small die area. However, its linearity is limited by the non-linear MOS transistors in weak inversion. In this Letter, a new PR topology is proposed, employing a feedback loop that continuously adjusts the voltage at the shared gate node of the PR with the input signal. The proposed architecture substantially increases the linearity and impedance of the PR. [ABSTRACT FROM AUTHOR]

The alignment of carbon nanotubes (CNT) is the fundamental requirement to ensure their excellent functions but seems to be desolated in recent years. A facile method, hot-press combined with peel-off (HPPO), is introduced here, through which CNT can be successfully vertically aligned on the polymeric membrane substrate. Shear force and mechanical stretch are proposed to be the main forces to align the tubes perpendicular to the substrate surface during the peel-off process. The alignment of CNT keeps its orientation in a thin hybrid membrane by dip-coating cellulose acetate dope solution. It is expected that the stable alignment of CNT by HPPO would contribute to the realization of its potential applications. [ABSTRACT FROM AUTHOR]

Background: Gastric cancer is 2th most common cancer in China, and is still the second most common cause of cancer-related death in the world. Successful development of safe and effective nanoprobes for in vivo gastric cancer targeting imaging is a big challenge. This study is aimed to develop folic acid (FA)-conjugated silica coated gold nanoclusters (AuNCs) for targeted dual-modal fluorescent and X-ray computed tomography imaging (CT) of in vivo gastric cancer cells. Method: AuNCs were prepared, silica was coated on the surface of AuNCs, then folic acid was covalently anchored on the surface of AuNCs, resultant FA-conjugated AuNCs@SiO2 nanoprobes were investigated their cytotoxicity by MTT method, and their targeted ability to FR(+) MGC803 cells and FR(-) GES-1 cells. Nude mice model loaded with MGC803 cells were prepared, prepared nanoprobes were injected into nude mice via tail vein, and then were imaged by fluorescent and X-ray computed tomography (CT) imaging. Results: FA-conjugated AuNCs@SiO2 nanoprobes exhibited good biocompatibility, and could target actively the FR (+) MGC-803 cells and in vivo gastric cancer tissues with 5 mm in diameter in nude mice models, exhibited excellent red emitting fluorescence imaging and CT imaging. Conclusion: The high-performance FA-conjugated AuNCs@SiO2 nanoprobes can target in vivo gastric cancer cells, can be used for fluorescent and CT dual-mode imaging, and may own great potential in applications such as targeted dual-mode imaging of in vivo early gastric cancer and other tumors with FR positive expression in near future. [ABSTRACT FROM AUTHOR]

The interactions of poly(phenylene ethynylene) (PPE)-based cationic conjugated polyelectrolytes (CPEs) and oligo-phenylene ethynylenes (OPEs) with E. coli cells are investigated to gain insights into the differences in the dark killing mechanisms between CPEs and OPEs. A laboratory strain of E. coli with antibiotic resistance is included in this work to study the influence of antibiotic resistance on the antimicrobial activity of the CPEs and OPEs. In agreement with our previous findings, these compounds can efficiently perturb the bacterial cell wall and cytoplasmic membrane, resulting in bacterial cell death. Electron microscopy imaging and cytoplasmic membrane permeability assays reveal that the oligomeric OPEs penetrate the bacterial outer membrane and interact efficiently with the bacterial cytoplasmic membrane. In contrast, the polymeric CPEs cause serious damage to the cell surface. In addition, the minimum inhibitory concentration (MIC) and hemolytic concentration (HC) of the CPEs and OPEs are also measured to compare their antimicrobial activities against two different strains of E. coli with the compounds' toxicity levels against human red blood cells (RBC). MIC and HC measurements are in good agreement with our previous model membrane perturbation study, which reveals that the different membrane perturbation abilities of the CPEs and OPEs are in part responsible for their selectivity towards bacteria compared to mammalian cells. Our study gives insight to several structural features of the PPE-based CPEs and OPEs that modulate their antimicrobial properties and that these features can serve as a basis for further tuning their structures to optimize antimicrobial properties. [ABSTRACT FROM AUTHOR]

Boilers in Beijing Thermal Power Plant of Zhongdian Guohua Co. in China are coal-fired with natural circulation and tangential fired method, and the economical continuous rate is 410 ton per hour of steam. Hybrid coal reburning/SNCR technology was applied and it successfully reduced NOx to about 170 mg/Nm3 from about 540 mg/Nm3, meanwhile ammonia slip was lower than 10 ppm at 450–210 t/h load and the total reduction efficiency was about 70%. Normal fineness pulverized coal from the bin was chosen as the reburning fuel and the nozzles of the upper primary air were retrofitted to be used as the reburning fuel nozzles. The reducing agent of SNCR was an urea solution, and it was injected by the four layer injectors after online dilution. At 410 t/h load, NOx emission was about 300 mg/Nm3 when the ratio of reburning fuel to the total fuel was 25.9%–33.4%. Controlling the oxygen content of the gas in the reversal chamber to less than 3.4% resulted in not only low NOx emission but also high combustion efficiency. Ammonia slip distribution in the down gas pass was uneven and ammonia slip was higher in the front of the down gas pass than in the rear of the down gas pass. NSR and NOx reduction were proportional to each other and usually resulted in more ammonia slip with reduction in NOx. About 100 mg/Nm3 NOx emission could be achieved with about 40 ppm NH3 slip at 300–450 t/h, and ammonia slip from the SNCR reactions could be used as reducing agent of SCR, which was favorable for the future SCR retrofit. [ABSTRACT FROM AUTHOR]

A pair of cationic phenylene ethynylene oligomers (OPEs) have been synthesized, and their optical properties have been studied in solution with and without added scaffold materials, including carboxymethylcellulose, carboxymethylamylose, and Laponite. The OPEs are strongly fluorescent in methanol solution, but in water, the fluorescence yield is suppressed. The addition of scaffolds to aqueous solutions of OPEs leads to a red shift in the absorption and in most cases a significant increase in the fluorescence quantum yield. The effects most likely arise because of template-induced formation of linear J-dimers or possibly because of planarization, which give rise to an effective increase in the conjugation length of OPEs. [ABSTRACT FROM AUTHOR]

The complete sequence (14 971 bp) of the Ruspolia dubia mitochondrial genome was determined and annotated. The genome contains the gene content, base composition, and codon usage typical of metazoan mitochondrial genomes. All 37 genes are conserved in the positions observed most frequently in insect mitochondrial genome structures. The secondary structures of both small subunit and large subunit rRNA were predicted. The most unusual features found were the initiation codon (TTA) of COI and a short A+T-rich region of 70 bp in length. In addition, a short, highly conserved polythymidine stretch that was previously described in Orthoptera and Diptera was also present in the A+T-rich region. La séquence complète (14 971 pb) du génome mitochondrial du Ruspolia dubia a été déterminée et annotée. Le génome affiche un contenu génique, une composition nucléotidique et un usage des codons typiques des génomes mitochondriaux chez les métazoaires. Les 37 gènes sont conservés à des positions observées le plus fréquemment chez les génomes mitochondriaux des insectes. Les structures secondaires des petits et grands ARNr ont été prédites. Les caractéristiques les plus inhabituelles étaient le codon d’initiation (TTA) du COI et une petite région de 70 pb riche en A+T. De plus, seule une courte suite polythymidinique fortement conservée et décrite antérieurement chez les orthoptères et les diptères est également présente au sein de la région riche en A+T. [ABSTRACT FROM AUTHOR]

Oxy-fuel combustion is a key technology to realize CO2 capture and storage in coal-fired power boilers in the future. In recent years, there have been extensive studies on it. This review summarizes some key results of fundamental research on oxy-coal combustion. By comparing with traditional coal-fired boiler with air combustion in power station, the typical characteristics of oxy-coal combustion are introduced from four aspects: combustion, heat transfer, pollutant emission, and numerical simulation; so that readers have a relatively comprehensive understanding of fundamental research on oxy-fuel combustion. Furthermore, some scientific issues in future research are summarized. The paper is both academic and popular, providing basic knowledge and academic direction inspiration for scholars or graduate students who are about to engage in oxy-fuel combustion research. [ABSTRACT FROM AUTHOR]

In this study, a thermal-balance model is established for energy calculation of a new solar-fuel assisted thermophotovoltaic system, which could save fossil fuels and improve the grade of solar energy. The coupling effects of key parameters such as concentrate ratio, absorber area, emitter area, etc. on the system efficiency are determined. Besides, the effect of solar energy on the fuel saving is investigated. The results show that the solar-fuel assisted thermophotovoltaic system cannot only increase the output power of photovoltaic cells by nearly 25 kW/m2 compared to fuel-driven thermophotovoltaic but also increase the electrical efficiency by nearly 10 percentage points. Furthermore, it also saves fuel by up to 76%. It is pointed out that improving the absorptance of solar absorber is the key for system optimization. This study provides a reference for the design and application of solar thermophotovoltaic technology. [ABSTRACT FROM AUTHOR]

Barcode libraries are generally assembled with two main objectives in mind: specimen identification and species discovery/delimitation. In this study, the standard COI barcode region was sequenced from 681 specimens belonging to katydids (Tettigoniidae), cave crickets (Rhaphidophoridae), and leaf-rolling crickets (Gryllacrididae) from Zhejiang Province, China. Of these, four COI-5P sequences were excluded from subsequent analyses because they were likely NUMTs (nuclear mitochondrial pseudogenes). The final dataset consisted of 677 barcode sequences representing 90 putative species-level taxa. Automated cluster delineation using the Barcode of Life Data System (BOLD) revealed 118 BINs (Barcodes Index Numbers). Among these 90 species-level taxa, 68 corresponded with morphospecies, while the remaining 22 were identified based on reverse taxonomy using BIN assignment. Thirteen of these morphospecies were represented by a single barcode (so-called singletons), and each of 19 morphospecies were split into more than one BIN. The consensus delimitation scheme yielded 55 Molecular Operational Taxonomic Units (MOTUs). Only four morphospecies (Imax > DNN) failed to be recovered as monophyletic clades (i.e., Elimaea terminalis, Phyllomimus klapperichi, Sinochlora szechwanensis and Xizicus howardi), so it is speculated that these may be species complexes. Therefore, the diversity of katydids, cave crickets, and leafrolling crickets in Zhejiang Province is probably slightly higher than what current taxonomy would suggest. [ABSTRACT FROM AUTHOR]

Three series of cationic oligo p-phenyleneethynylenes (OPEs) have been synthesized to study their structure−property relationships and gain insights into the transition from molecular to macromolecular properties. The absorbance maxima and molar extinction coefficients in all three sets increase with increasing number of repeat units; however, the increase in λmaxbetween the oligomers having 2 and 3 repeat units is very small, and the oligomer having 3 repeat units shows virtually the same spectra as a p-phenyleneethynylene polymer having 49 repeat units. A computational study of the oligomers using density functional theory calculations indicates that while the simplest oligomers (OPE-1) are fully conjugated, the larger oligomers are nonplanar and the limiting “segment chromophore” may be confined to a near-planar segment extending over three or four phenyl rings. Several of the OPEs self-assemble on anionic “scaffolds”, with pronounced changes in absorption and fluorescence. Both experimental and computational results suggest that the planarization of discrete conjugated segments along the phenylene−ethynylene backbone is predominantly responsible for the photophysical characteristics of the assemblies formed from the larger oligomers. The striking differences in fluorescence between methanol and water are attributed to reversible nucleophilic attack of structured interfacial water on the excited singlet state. [ABSTRACT FROM AUTHOR]

The article presents a study that assesses the impact of 1-bromopropane (1-BP) on female workers in three 1-BP factories in Yixing, China. Researchers did four-time investigations on 60 female and 26 male workers and found 1-BP decreased the sensory nerve conduction velocity of female workers' aural nerve, red blood cells and hematocrit. They concluded that it induced dose-dependent neurotoxicity of female workers.

In this paper, a computational method for solving for the 1-D heat conduction temperature field is proposed based on a data-driven approach. The traditional numerical solution requires algebraic processing of the heat conduction differential equations, and necessitates the use of a complex mathematical derivation process to solve for the temperature field. In this paper, a temperature field solution model called hidden temperature method is proposed. This model uses an artificial neural network to establish the correspondence relationship of the node temperature values during the iterative process, so as to obtain the "Data to Data" solution. In this work, one example of 1-D steady-state and three examples of 1-D transient state are selected, and the calculated values are compared to those obtained by traditional numerical methods. The mean-absolute error of the steady-state is only 0.2508, and among the three transient cases, the maximum mean-square error is only 2.6875, indicating that the model is highly accurate in both steady-state and transient conditions. This shows that the hidden temperature method simulation can be applied to the solution of the heat conduction temperature field. This study provides a basis for the further optimization of the hidden temperature method algorithm. [ABSTRACT FROM AUTHOR]

Lead (Pb) is a toxic heavy metal affecting human health; it is known to be harmful to various organs or systems, yet the mechanisms by which Pb influences immune cell development remain to be defined. In this study, we show that Pb exposure (1250ppm via drinking water) selectively impacted the development of myeloid cells (myelopoiesis). After Pb treatment of adult C57BL/6 mice, the numbers of granulocyte-macrophage progenitors (GMP) were consistently reduced, whereas the numbers of myeloid cells were increased at week (wk) 1 and decreased at wk8 after initiating the Pb exposure. Functional assays indicate that Pb accelerated GMP differentiation in a reactive oxygen species-dependent manner after treatment for 1 week and inhibited common myeloid progenitor differentiation by upregulating interferon regulatory factor 8 (IRF8) expression after treatment for 8 weeks. Consistent with the distinct Pb influences on myeloid cells observed at wk1 and wk8, Pb caused an inflammatory environment in vivo at wk8, but not at wk1. Furthermore, like the observations in mice during the Pb exposure, bloods from humans occupationally exposed to Pb had their numbers of monocytes, neutrophils and GMP negatively associated with the Pb concentration, whereas IRF8 expression in common myeloid progenitor, but not GMP, was positively correlated with the Pb concentration. These data suggest an occupationally relevant level of Pb exposure preferentially influences myelopoiesis involving reactive oxygen species and IRF8, which may contribute to the current understanding of the hematopoietic toxicology of Pb. [ABSTRACT FROM AUTHOR]

Background: Animal studies suggest that bisphenol A (BPA) may perturb pubertal development in females. However, evidence from human studies is limited.Methods: This was a cross-sectional study to investigate the association between BPA exposure and pubertal development in school-aged girls. A total of 655 girls aged 9-18 years were selected from three schools in Shanghai, from May to June 2011. We collected one single spot urine sample from each girl. Urine BPA concentrations were measured by modified high-performance liquid chromatography and categorized according to LOD and the median of those above LOD. Pubertal development status was assessed by using Tanner staging, and age at menarche was collected as a milestone for mid-puberty. Modified Poisson regression was used to estimate adjusted prevalence ratios (PRs) and 95% confidence intervals (CIs).Results: After adjustment for potential confounders, girls with detected BPA were more likely to have delayed menarche, a mid-puberty event, compared with girls with undetectable BPA; the prevalence ratios (PR) were 0.73 (0.56, 0.95) for those with moderate BPA(LOD-median) and 0.72 (0.52, 0.99) for those with high BPA(>median), respectively. Girls aged 9-12 years with detected BPA were more likely to have reached pubic hair stage 2, the indicator of pubarche; while among girls aged >15 years, those with detected BPA were less likely to have reached pubic hair stage 5, the late stage of pubic hair development.Conclusions: BPA exposure was associated with alterations in the timing of pubertal development. Results in the present study should be interpreted with caution because of its cross-sectional nature and the limited sample size in each age group. [ABSTRACT FROM AUTHOR]

Mitochondria are essential organelles and important targets for environmental pollutants. The detection of mitochondrial biogenesis and generation of reactive oxygen species (ROS) and p53 levels following low-dose methylmercury (MeHg) exposure could expand our understanding of underlying mechanisms. Here, the sensitivity of immortalized human neural progenitor cells (ihNPCs) upon exposure to MeHg was investigated. We found that MeHg altered cell viability and the number of 5-ethynyl-20-deoxyuridine (EdU)-positive cells. We also observed that low-dose MeHg exposure increased the mRNA expression of cell cycle regulators. We observed that MeHg induced ROS production in a dose-dependent manner. In addition, mRNA levels of peroxisome-proliferator-activated receptor gammacoactivator-1α (PGC-1α), mitochondrial transcription factor A (TFAM) and p53-controlled ribonucleotide reductase (p53R2) were significantly elevated, which were correlated with the increase of mitochondrial DNA (mtDNA) copy number at a concentration as low as 10 nM. Moreover, we examined the expression of microRNAs (miRNAs) known as regulatory miRNAs of p53 (i.e., miR-30d, miR-1285, miR-25). We found that the expression of these miRNAs was significantly downregulated upon MeHg treatment. Furthermore, the overexpression of miR-25 resulted in significantly reducted p53 protein levels and decreased mRNA expression of genes involved in mitochondrial biogenesis regulation. Taken together, these results demonstrated that MeHg could induce developmental neurotoxicity in ihNPCs through altering mitochondrial functions and the expression of miRNA. [ABSTRACT FROM AUTHOR]

Fluorochloridone (FLC) is a herbicide used worldwide that is thought to be safe. However, due to its potential genotoxicity, cytotoxicity, and even systematic toxicity, there are increasing concerns about human exposure to this compound. Thus, the metabolism and bioactivation of FLC was investigated. After oral administration to mice, 27 metabolites were identified by ultrahigh performance liquid chromatography-electrospray ionization-quadrupole time-of-flight-mass spectrometry and with further structural identification by nuclear magnetic resonance spectroscopy. Hydroxylation and oxidative dechlorination were the major phase I pathways, while glutathione (GSH) and N-acetylcysteine conjugations were two major phase II pathways, indicating the formation of a reactive intermediate. In vitro microsomal and cytosolic studies revealed that a GSH conjugate (M13) was the predominant metabolite of FLC formed through a nucleophilic SN2 substitution of 3-Cl by GSH; this pathway is NADPH independent and accelerated by glutathione S-transferase (GST). Further, a kinetic study showed that M13 formation in both human liver microsomes and cytosols obeyed typical Michaelis-Menten kinetics. The maximum clearance (Vmax/Km) of GSH conjugation in human liver microsomes was approximately 5.5-fold higher than human liver cytosol, thus implying that microsomal GST was mainly responsible for M13 formation. These findings are important for understanding the potential hazard of human exposure to FLC. [ABSTRACT FROM AUTHOR]

This study developed a new method for the analysis of 20 phenolic compounds in human urine. The urine samples were prepared by hydrochloric acid (HCl) hydrolysis, liquid–liquid extraction (LLE), and solid-phase extraction (SPE) cleanup. We found that HCl hydrolysis is of similar effectiveness to, and much cheaper than, the traditional enzymatic method. Vanillic acid was co-eluted with butyl paraben and interfered with the determination of butyl paraben in urine. K2CO3-treated-silica-gel SPE was designed to efficiently eliminate interference from the endogenous organic acids (especially vanillic acid) in urine. After derivatization, the samples were analyzed by large-volume-injection gas chromatography–tandem mass spectrometry (LVI-GC–MS–MS). Good linearity (R 2 ≥ 0.996) was established in the range 0.1–100 ng mL−1 for all analytes. Method detection limits (MDLs) were 0.7–9.8 pg mL−1. Intraday (n = 5) and interday (n = 5 days) validation was performed, with satisfactory accuracy (recovery: 70–126 % and 73–107 %, respectively) and precision (RSD ≤ 19 %) at two levels (low: 0.1 and 0.5 ng mL−1; high: 5 and 10 ng mL−1). The method was used in a population study and achieved more than 85 % detection for most analytes; mean analyte concentrations were in the range 0.01–185 ng mL−1. The method is suitable for the analysis of multiple phenolic metabolites in human urine. [ABSTRACT FROM AUTHOR]

Aberration during the development of the central nervous system (CNS) due to environmental factors underlies a variety of adverse developmental outcomes. Paraquat (PQ) is a widely studied neurotoxicant that perturbs the normal structure/function of adult CNS. Yet, the impacts of PQ exposure on the developing CNS remain unclear. miRNAs represent a class of small non-coding RNA molecules involved in the regulation of neural development. Thus in the present study, we analyzed the impacts of PQ on the miRNome of human neural progenitor cells (hNPCs) during proliferation by using the Exiqon miRCURY™ LNA Array. A total of 66 miRNAs were identified as differentially expressed in proliferating hNPCs upon PQ treatment. miRTarBase prediction identified 1465 mRNAs, including several genes (e.g., nestin, sox1, ngn1) previously proved to be associated with the neural proliferation and differentiation, as target genes of PQ-induced differentially expressed miRNAs. The database for annotation, visualization and integrated discovery (DAVID) bioinformatics analysis showed that target genes were enriched in regulation of cell proliferation and differentiation, cell cycle and apoptosis as well as tumor protein 53 (p53), Wnt, Notch and mitogen-activated protein kinases (MAPK) signaling pathways (p < 0.001). These findings were confirmed by real-time RT-PCR. Based on our results we conclude that PQ-induced impacts on the miRNA profiling of hNPCs undergoing proliferation may underlie the developmental neurotoxicity of PQ. [ABSTRACT FROM AUTHOR]

Background MicroRNAs (miRNAs) are a large group of post-transcriptional gene regulators that potentially play a critical role in tumorigenesis. Increasing evidences indicate that miR-744 deregulated in numerous human cancers including hepatocellular carcinoma (HCC). However, its role in HCC carcinogenesis remains poorly defined. In this study, we investigated the roles of miR-744 in tumor growth of HCC. Methods Quantitative reverse-transcription polymerase chain reaction (qRT-PCR) was conducted to detect the expression of miR-744 and Immunohistochemistry was performed to detect expression of c-Myc in HCC specimens and adjacent normal tissues. The biological functions of miR-744 were determined by cell proliferation and cell cycle assay. Furthermore, cell lines transfected with miR-744 mimics were analyzed in vitro. Luciferase reporter assays was performed to confirm whether miR-744 regulated the expression of c-Myc. Results Our results showed that the expression of miR-744 was frequently down-regulated in both HCC tissues and cells. Furthermore, restoration of miR-744 in HCC cells was statistically correlated with decrease of cell growth and restored G1 accumulation. Luciferase assay and Western blot analysis revealed that c-Myc is a direct target of miR-744. Down-regulation of miR-744 and up-regulation of c-Myc were detected in HCC specimens compared with adjacent normal tissues. Moreover, restoration of miR-744 rescues c-Myc induced HCC proliferation. Conclusions Our data suggest that miR-744 exerts its tumor suppressor function by targeting c-Myc, leading to the inhibition of HCC cell growth. miR-744 may serve as a potentially useful target for the miRNA-based therapies of HCC in the future. [ABSTRACT FROM AUTHOR]

Background: Associations between airborne particles and health outcomes have been documented worldwide; however, there is limited information regarding health effects associated with different particle sizes. Objectives: We explored the association between size-fractionated particle number concentrations (PNCs) and daily mortality in Shenyang, China. Methods: We collected daily data on cause-specific mortality and PNCs for particles measuring 0.25-10 ?m in diameter between 1 December 2006 and 30 November 2008. We used quasi-Poisson regression generalized additive models to estimate associations between PNCs and mor­tality, and we used natural spline smoothing functions to adjust for time-varying covariates and long-term and seasonal trends. Results: Mean numbers of daily deaths were 67, 32, and 7 for all natural causes, cardiovascular diseases, and respiratory diseases, respectively. Interquartile range (IQR) increases in PNCs for particles measuring 0.25-0.50 μm were significantly associated with total and cardiovascular mortality, but not respiratory mortality. Effect estimates were larger for PNCs during the warm season than the cool season, and increased with decreasing particle size. IQR increases in PNCs of 0.25-0.28 μm, 0.35-0.40 μm, and 0.45-0.50 μm particles were associated with 2.41% (95% CI: 1.23, 3.58%), 1.31% (95% CI: 0.52, 2.09%), and 0.45% (95% CI: 0.04, 0.87%) higher total mor­tality, respectively. Associations were generally stable after adjustment for mass concentrations of ambient particles and gaseous pollutants. Conclusions: Our findings suggest that particles < 0.5 μm in diameter may be most responsible for adverse health effects of particulate air pollution and that adverse health effects may increase with decreasing particle size. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to examine a possible relationship between lead nephropathy and its effects on the skeleton in male population occupationally exposed to lead in China. Methods: One hundred and fifty-five lead-exposed male workers in a storage battery plant in Shanghai were selected as the exposed subjects while the 36 healthy male officers in the plant who were not occupationally exposed to lead were treated as the control. Blood lead (BPb) and urine lead were used as biomarkers for exposure. Z score, urine hydroxyproline (HYP), serum alkaline phosphatase (bone isoenzyme) (BALP) and serum osteocalcin (BGP) were used as biomarkers for bone effects. Urine N-acetyl-β-D-glucosaminidase (UNAG) and urine albumin (UALB) were applied as biomarkers of renal tubular and glomerular dysfunction. Bone mineral density was measured by the monophoton absorptiometry (SPA-4). Results: It was found that there were linear correlate relationships between lead exposure and NAG, ALB, BALP, BGP, HYP, Z score (P Z score would decrease with the increase of lead exposure. Of 21 subjects with osteoporosis, nine subjects were suffering from renal dysfunction. The prevalence of renal dysfunction (42.86%) was significantly higher in the subjects with osteoporosis than in those without osteoporosis (17.65%) (χ2 = 7.310, P = 0.007). The prevalence of osteoporosis had relationship with renal tubular damage, but not with renal glomerular damage. This showed that glomerular dysfunction plays a smaller role than tubular dysfunction in the causation of bone damage. Benchmark dose in terms of BPb was calculated using Benchmark Dose Software Version 1.3.2 software. The benchmark dose lower limit of a one-sided 95% confidence interval (BMDL) for 10% excess risk was also determined. It was found that BMDL−05 for BALP, UNAG, BGP, HYP, Z score and UALB of BPb increased sequentially. The BMDL values for UNAG (10.13 μg dL−1) were lower than those of Z score (14.17 μg dL−1). Conclusions: The present study has thus demonstrated the combined adverse effects (osteoporosis and renal dysfunction) caused by occupational exposure to lead. There was a dose–response relationship between lead exposure and prevalence of osteoporosis, renal dysfunction and bone metabolism. The renal dysfunction might develop earlier than osteoporosis. Osteoporosis caused by lead was related to the change of bone metabolism and renal dysfunction, which was especially to tubular damage but not to glomerular damage. [ABSTRACT FROM AUTHOR]

Bioleaching has become a research hotspot, as a simple and effective technology for metal extraction from low-grade ores. During the process of bioleaching, the chemoautotroph organisms play a key role. However, their growth and activity are greatly restrained by the stress brought by over acidic extracellular environment in industrial practice. This research effort focused on the transciptome profile discrepancies of the typical bioleaching species Acidithiobacillus ferrooxidans ATCC 23270 when challenged by a pH downshift to pH 1.2 using the method of microarray. A total of 1853 genes were found to be significantly affected under acid stress challenge for 1 hr, and the array data revealed that A. ferrooxidans ATCC 23270 actively responses to acid stress from several levels: cell envelope level, cytoplasm level and transcription level. One remarkable change is that the ion transporters and the synthesis of glutamine and polyamines were regulated in chemoautotrophic A. ferrooxidans ATCC 23270 under acid stress, while in contrast, typical he- terotrophic bacteria Escherichia coli depended on up-regulation of ATP synthase F0F1 and glutamate decarboxylase system. More specifically, the alkaline substances generated by glnA, glnB, glnD, glnE etc. were functional in buffering the cytoplasm pH, and certain proton pumps such as cytoplasm protons plasma-membrane proton transport P-type ATPase played an important role in proton expulsion to keep cytoplasm pH in certain range. The new information provided in this study could lead to a better understanding of the acid resistance mechanisms exhibited by autotrophic acidophilic bacteria. [ABSTRACT FROM AUTHOR]

The light-induced antibacterial activity of symmetric and asymmetric oligophenylene ethynylenes (OPEs) was investigated against Gram-positive (Staphylococcus aureusand Staphylococcus epidermidis) and Gram-negative (Escherichia coli) bacteria. To understand the light-induced biocidal effect better, the transient absorption and triplet lifetime of OPEs were studied in methanol and water. A higher triplet lifetime was observed for OPE samples in water than in methanol. The magnitudes of the changes in optical density (ΔOD) of the S-OPE-n(H) series of symmetric oligomers are much higher than that of the asymmetric OPE-nseries in water and are generally correlated with the singlet oxygen yield. It was found that the antibacterial activity against both Gram-positive and Gram-negative bacteria is size-, concentration-, and time-dependent. The light-induced antibacterial activity may result from the coordinated interactions of membrane disruption and interfacial or intracellular singlet oxygen generation, and the dominant factor is most likely the latter. The results obtained in this study will aid in the design of more efficient biocides in the future. [ABSTRACT FROM AUTHOR]

Paraquat (PQ) has been demonstrated that the main target organ for the toxicity is the lung. This study aimed to investigate the potential protective effect of PDTC on the PQ-induced pulmonary damage. Fifty-four rats were divided into control, PQ-treated and PQ+PDTC-treated groups. Rats in the PQ group were administrated 40 mg/kg PQ by gastric gavage, and PDTC group with 40 mg/kg PQ followed by injection of 120 mg/kg PDTC (IP). On the days 3, 7, 14 and 21 after treatments, the activities of GSH-Px, SOD, MDA level and the content of HYP were measured. TGF-β1 mRNA and protein were assayed by RT-PCR and ELISA. MDA level in plasma and BALF was increased and the activities of GSH-Px and SOD were decreased significantly in the PQ-treated groups (P < .05) compared with control group. While the activities of GSH-Px and SOD in the PQ+PDTC-treated groups was markedly higher than that of PQ-treated groups (P < .05), and in contrast, MDA level was lower. TGF-β1 mRNA and protein were significantly lower in the PQ+PDTC-treated groups than that of PQ-treated groups (P < .05). The histopathological changes in the PQ+PDTC-treated groups were milder than those of PQ groups. Our results suggested that PDTC treatment significantly attenuated paraquat-induced pulmonary damage. [ABSTRACT FROM AUTHOR]