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Matrix-type certified reference materials (CRMs) prepared from real environmental samples are used to ensure the reliability of environmental analyses and the comparability of results from different laboratories. Internationally, the National Institute of Standards and Technology (NIST) in the USA, the Institute for Reference Materials and Measurements (IRMM) of the Joint Research Centre (JRC) in the European Union, and the UK Laboratory of the Government Chemist (LGC) have developed sediment CRMs for Polycyclic Aromatic Hydrocarbons (PAHs). Although some matrix-type CRMs are available for the quantification of PAHs in sediment and soils, their PAH contamination is mostly at the mg/kg level. Thus, they are not suitable for the QA of analyses of PAHs at the μg/kg level. In China, by restricting preparative techniques and value-assignment techniques of natural matrix CRMs, no CRMs of PAHs in sediment have been developed. Therefore, based on the foreign research experience, CRMs of PAHs in river sediment have been developed for Chinese environmental monitoring and scientific research. A method for developing CRMs of PAHs in sediment is described in this paper. Sediment sample was collected from Songhua River, and air-dried, ground, homogenized and sterilized. A good homogeneity was obtained by the testing for 16 kinds of PAHs from 15 units selected by a random stratified scheme covering the whole batch, and 3 sub-samples were analyzed in each unit. At 30℃ without direct sunlight, the concentrations of 16 PAHs were not changed during monitoring period of 16 months. Based on the results from difference analytical techniques including Gas Chromatography/Mass Spectrometry and Reversed-phase Liquid Chromatography by 11 collaborating laboratories, reference values for 14 PAHs are given, and reference values for 2 PAHs are in the range of 6.9-158 μg/kg. Expanded uncertainty of each PAH is 1.5-25 μg/kg. Since the values of PAHs in the CRM are much lower than those in other CRMs and are comparable to the actual PAHs content in sediment or soil, the CRMs are suitable for PAH monitoring in sediment and soil samples and method validation.

In this paper, we show that a minimal state space realization in Jordan canonical form for linear multivariable continuous‐time systems described by rational transfer function matrices could be obtained in a natural and basic way by using the concept of Nerode equivalence. While the minimal state space realization is known, the contribution of this note is to provide an alternative realization procedure which is directly introduced in a simple and self‐contained manner. Both scalar and multivariable cases in the continuous‐time setting are discussed. The presentation also provides a concrete construction of rational vector function with preassigned poles to interpolate any 2‐norm bounded analytical vector function in the open left‐half of the complex plane. The basic idea of Nerode equivalence is that the state can be identified with a corresponding equivalence class of inputs. For a linear finite dimensional time‐invariant continuous‐time system, the zero state is identified with the kernel of certain Hankel operator. This characterization via Nerode equivalence class sheds light on the construction of state for general nonlinear input–output systems. [ABSTRACT FROM AUTHOR]

The rapid growth and intensification of freshwater fishery can cause imbalances between phosphorus (P) input in feed and its output in produce. This aquaculture can result in enriching exogenous P in fishponds and, consequently, accelerates the process of eutrophication. To assess relations among input, accumulation, release of P and as a consequence degrading water quality in terms of chlorophyll-a (Chl-a) in freshwater fishponds, fourteen fishponds with feed supply, nine fishponds without feed supply, and five nonfish ponds in Shaoxing Plain, southeast China were selected for comparing P accumulation in their waters and surface sediments. Surface sediment samples were collected from each pond to evaluate their total P, water soluble P, Olsen P, algal available P, and P fractions. Water samples were also collected from the ponds to measure concentrations of dissolved P and Chl-a. Total P in the sediments ranged from 0.88 to 1.73 g/kg in the fishponds with feed supply, that in the non-fish ponds ranged from 0.47 to 0.86 g/kg. Organic P, accounted for 23% to 60% of total P in the sediments, was an important P fraction and increased linearly with increasing organic matter. Long-term application of feeds resulted in increased P availability in the bottom sediments and degradation of water quality in the freshwater fishponds. Compared with non-fish ponds, sediments from the feed-supplied fishponds contained considerably higher Olsen P, algal available P, and water soluble P. Higher proportions of the labile P (NH_4Cl-P) and potentially labile P (NaOH-IP) were also found in the sediments from the fishponds. High solubility of P in the sediments resulted in elevation of P and chlorophyl1-a concentration in the pond water. The dissolved P concentration in the pond water increased in the order of non-fish ponds (12 μg/L) < fishponds without feed supply (24 μg/L) < fishponds with feed supply (66 μg/L). Linear correlations between concentrations of total P, Olsen-P, algal available P, water-soluble P and P concentration in saturation extracts in the sediments and dissolved P in the pond water indicated that there was a buffering action of the sediment constituents on the dissolved P. [ABSTRACT FROM AUTHOR]

Heavy metals can be introduced into urban soils at the same time. Therefore, their selective retention and competitive adsorption by the soils become of major importance in determining their availability and movement throughout the soil. In this study, the availability and mobility of six heavy metals in eight urban soils collected from different cities of Zhejiang Province, southeastern China were assessed using distribution coefficients (Kd) and retardation factor (Rf). The results showed that there were great differences in the Kd and Rf among the tested soils. The adsorption sequences were Cr>Pb>Cu>Cd>Zn>Ni, and the Kd decreased with increasing levels of metal addition. Ni generally has the lowest Rf values followed closely by Cd, and Zn whereas Cr and Pb reached the highest values. The results suggest that Ni and Zn have the highest mobility associated to the lowest adsorption, Cr and Pb present the opposite behavior. Correlation analysis indicates that soil pH, CaCO_3 content, and cation exchange capacity (CEC) are key factors controlling the solubility and mobility of the metals in the urban soils. [ABSTRACT FROM AUTHOR]

The Ministry of Health in Taiwan has promoted the award campaign to assure the health web information since 2002. The 98 ever-awarded web sites were reexamined with the new set of quality indicators in 2007. The results show that the overall quality only at an acceptance level and much work needs to be done in credibility and site interaction. [ABSTRACT FROM AUTHOR]

Nanoscale zero-valent iron (nZVI) shows excellent reduction of Cr(Ⅵ), but the passivation on its outer surface can restrict its longevity and performance. To tackle this problem, this work introduced Shewanella oneidensis MR-1, a dissimilatory iron-reducing bacterium, into the chemical reduction system of aged nZVI/biochar (B) and Cr(Ⅵ). The potential synergistic effect of Cr(Ⅵ) reduction of aged nZVI/B and MR-1 was systematically investigated under varying conditions. The results indicated that aged nZVI/B and MR-1 exhibited a synergistic effect at a pH of 7, and the removal rate of Cr(Ⅵ) increased by 51.3%. Further research showed that the synergistic effect could be attenuated with the increase in the initial Cr(Ⅵ) concentration and enhanced with the increase in the MR-1 concentration. The XPS spectra confirmed that Cr(Ⅵ) was mainly removed through reduction. The dissimilatory iron-reducing ability of MR-1 played a key role in enhancing the Cr(Ⅵ) reduction. The reductive dissolution of the oxidation layers not only released reactive sites inside the nZVI, but also reduced Cr(Ⅵ) by producing ferrous ions. Moreover, B promoted the reduction by dispersing the nZVI and mediating the extracellular electron transfer. This study provides a new insight into solving the passivation problem of the long-term application of nZVI for Cr(Ⅵ) removal, which is considered a promising solution for synergistically improving the performance of nZVI in environmental remediation.

Objective: To observe the expressions of nerve growth factor (NGF) and its tyrosine kinase A (TrkA) receptor on alveolar macrophage in a rat model of chronic obstructive pulmonary disease (COPD)., Methods: Forty healthy male SD rats were randomly divided into a control group and a COPD group. The COPD model was established by exposing the rats to cigarette smoke for 6 months, and lung function changes were measured. Lung histopathological changes were detected by HE staining. The expression of NGF protein in the supernatant of alveolar macrophage (AM) culture medium was detected by ELISA. Confocal microscopy was used to identify the separation and purification of AM from bronchoalveolar lavage fluid, and to detect semi-quantitatively the expression of TrkA receptor on AM. NGF and its TrkA receptor at the mRNA level were evaluated by real-time PCR. The differences among groups were calculated by one way ANOVA, and comparison between groups was made by t test., Results: Significant decrease of pulmonary compliance [(0.15 ± 0.03) ml/cm H(2)O (1 cm H2O = 0.098 kPa)] and minute ventilation [(0.045 ± 0.004) L], and significant increase of airway resistance [(0.038 ± 0.004) cm H2O×L(-1)×s(-1)] were found in the COPD group compared with the control group [(0.42 ± 0.05) ml/cm H2O and (0.102 ± 0.010) L and (0.016 ± 0.002) cm H2O×L(-1)×s(-1), t = 9.46 - 12.99, respectively, all P < 0.01]. Alveolar wall thinning, alveolar septa breakdown, alveolar enlargement and emphysema were significant in the COPD rats. The expression of NGF protein in the supernatant of AM culture medium was enhanced in the COPD group [(3.79 ± 1.52) ng/L] compared with the controls [(0.94 ± 0.27) ng/L, t = 4.13, P < 0.05]. Mean fluorescence intensity of TrkA protein on AM in the COPD group (19.5 ± 1.5) was higher than that in the control group (11.2 ± 1.9, t = 7.95, P < 0.05). The expressions of NGF and TrkA at mRNA level in the COPD group (24.8 ± 6.0 and 9.0 ± 3.3) were increased compared with the control group (1.0 ± 0.2 and 1.0 ± 0.4, t = 8.48 and 5.16, all P < 0.05)., Conclusions: The expressions of NGF and its TrkA receptor on AM in COPD group were increased, indicating that NGF and its TrkA receptor might be involved in the pathogenesis of COPD mediated by AM.

Aim: To study the relation between Respiratory Syncytial Virus infection and asthma development by measuring airway responsiveness (AR) and M2R function., Methods: Guinea pigs (n = 34) were randomly divided into 4 groups: Hep-2/NS group (group A, n = 9), RSV/NS group (group B, n =9), Hep-2/OVA group (group C, n = 8) and RSV/OVA group(group D, n = 8). On day 21 after infection we tested AR and M2R. Then counted eosinophils in BALF and observed pathological change., Results: Intraairway pressure(IP mmH20) of group B had no significant difference with group A(P > 0.01), and the extent of IP decrease also had no difference between groups A and B (P > 0. 05), but IP of C group were much higher than group A (P<0.05), with extent of IP decrease lower than group A (P < 0.05). And IP of group D were higher than group C (P < 0.01), with the extent of IP decrease much lower than group C (P < 0.05)., Conclusion: RSV infection could enhance OVA-induced M2R dysfunction, then develop AHR.

Aim: To explore the physiopathological mechanisms of airway injury and the effect on the airway responsiveness of rat by inhaled sulfur dioxide(SO2)., Methods: Sixteen SD male rats were divided randomly into 2 groups (n = 8): the control group and SO2 group. The control group was exposed o pure air. SO2 group was exposed to SO2 of the content 1.0 mg/(m(3) x h) 6h daily for consecutive 3 d. At 4th day, we determined the airway responsiveness, collected the bronchoalveolar lavage fluid (BALF), plasma and lung tissue. Then we counted the total cellular score in BALF, measured the plasma SP content and made the immunohistochemistry staining on the lung tissue (HE and SP methods)., Results: Compared with the control group, the total cellular score in BALF and plasma SP content in SO2 group's increased significantly ( P < 0.01). HE staining showed there were a great deal of inflammatory cells infiltration under the tunica mucosa bronchiorum; and SP immunohistochemistry staining indicated there were significant changes in numbers of SP-IR positive fibers of SO2group., Conclusion: Exposure to low concentration of SO2 would injure healthy rat's airway, and induce airway hyperresponsiveness, neurogenic inflammation is one of its critical pathophysiological mechanisms.

The Ministry of Health in Taiwan has promoted the award campaign to assure the health web information since 2002. The 98 ever-awarded web sites were reexamined with the new set of quality indicators in 2007. The results show that the overall quality only at an acceptance level and much work needs to be done in credibility and site interaction.

Objective: To construct a detection method of endogenous hydrogen sulfide (H2S) from erythrocytes., Methods: Prepared rat erythrocyte (10(6) cell) was added in 4 mL 2-amino-2-methyl-1,3-propanediol(225 mmol/L, pH=9.55) and ultrasonically lysed for 3 times. The erythrocyte lysis was transferred into a 25 mL Erlenmeyer flask and beta-mercaptopyruvate was added for final concentration of 2 mmol/L. Cryovial test tubes (2 mL) were used as the centre wells each contained 0.5 mL of 1% zinc acetate as trapping solution and a filter paper of 2.0x2.5 cm2 to increase the air/liquid contacting surface. The flasks containing reaction mixture and centre wells were flushed with N2 before being sealed with a double layer of Parafilm. Reaction was initiated by transferring the flasks from ice to a 37 degrees C shaking water bath. After incubation at 37 degrees C for 60 min, 0.5 mL of 50% trichloroacetic acid was added into the reaction mixture to stop the reaction. The flasks were sealed again and incubated at 37 degrees C for another 60 min to ensure a complete trapping of the H2S released from the mixture. Released H2S is absorbed by zinc acetate and generation zinc sulfide. The zinc sulfide formed is dissolved in a hydrochloric acid solution of amino-dimethylaniline (N,N-dimethyl-p-phenylenediamine), and methylene blue is formed within 10 min at room temperature in the presence of ferric chloride. The blue color of methylene blue is measured at 670 or 650 nm on spectrophotometer., Results: We first demonstrated the key enzymes of endogenous H2S generation-3-mercaptopyruvate sulfurtransferase (MPST) gene expression by RT-PCR. Endogenous H2S production from rat erythrocytes was 22.76+/-1.53 micromol/min/10(8) cells, about 4-folds as compared with to the liver and kidney tissues. However, the endogenous H2S production from erythrocyte by L-cysteine pathway was little detected., Conclusion: Endogenous H2S released from erythrocytes depended mainly on MPST pathway. Our method is effective to detect the erythrocytic endogenous H2S.

p73 gene is a new member of the tumor suppressor gene p53 family. They are similar in the structure and function of the coding protein, but they also have notable distinctions in other aspects. Many studies have shown that the abnormal p73 gene is associated with neuroblastoma, malignant melanoma, prostatic carcinoma, and lung cancer, et al. Recently, many studies have demonstrated that p73 gene may involve the occurrence and development of a portion of the digestive system carcinoma. This review summarized the present conditions of the p73 gene and its correlation with the occurrence, development, prognosis, and expression in the digestive system carcinoma. We suggested that the further study about the p73 gene may be helpful to recognize the nature of the carcinoma and bring wish to overcome it finally.