干旱区城市化对城市内河水质的影响研究——以吐曼河为例

随着城市社会经济的迅速发展，工业主导的城市化过程带来了许多城市生态环境问题，引起了城市内河水质的恶化。采用1996～2000年喀什市吐曼河水质观测数据、1990年与1999年卫星遥感图像和城市发展中有关的社会经济统计数据与土地利用资料，在3S技术的支持下，运用地表水污染综合指数法，对吐曼河水质进行评价，定量与定性相结合分析了干旱区城市化对城市内河水质的影响。结果表明：大气中的总悬浮颗粒是导致吐曼河水质严重污染的主要原因。此外，城市化所带来得人口增加、工业化与土地利用方式的改变也一定程度的影响了吐曼河的水质。     

Calibration of Hargreaves–Samani and Priestley–Taylor equations in estimating reference evapotranspiration in the Northwest of Iran

Accurate estimation of reference evapotranspiration (ET_o) is essential for water resources management and irrigation systems scheduling, especially in arid and semiarid regions such as Iran. In the present research, constant coefficients of Hargreaves–Samani (C_H–S) and Priestley–Taylor (C_P–T) equations were locally calibrated to estimate the ET_o based on the FAO–Penmen–Monteith (PM) method as standard method. For this purpose, meteorological data of eight synoptic stations located in the northwest of Iran were used during the period of 1997–2008. The outcomes showed that the values of C_H–S and C_P–T were 0.0026 (instead of 0.0023) and 1.68 (instead of 1.26), respectively. Also, at stations with high wind speed, the values of calibrated coefficients of C_H–S and C_P–T were maximum. Then, the estimated ET_o values using adjusted C_H–S and C_P–T coefficients were compared to the obtained actual ET_o values by PM method using root mean square error and mean bias error indices. The results indicated that the new calibrated H–S and P–T equations have good agreement with the PM method for estimation of the ET_o. Moreover, the equation of Ravazzani et al. was calibrated in the studied region. It was concluded that in general, the mentioned equation was shown better performance than original H–S equation.     

Long-term land-use change effects on phosphorus fractionation in Zrêbar Lake margin soils

The aim of this study was to survey long-term changes in phosphorus (P) fractions in soils in different land uses. Sequential extraction had been used to determine soil P fractionation on the basis of land-use change, i.e. native forest to vineyard and wetland to both alfalfa and wheat at the end of 30 and 20 years, respectively. The highest values of labile-P (L-P) fractions in surface soil layers were observed in the cultivated land. The calcium-bound P was the most affected fraction by land-use change with the lowest amount in the vineyard and the highest amount in the alfalfa land. Conversion of forest to vineyards causes P in the soils to be more vulnerable to transmission; thus, the least amount of total P (T-P) in vineyard may be attributed to the removal of sediment and sediment bond P from runoff in response to land-use changes. Average L-P in alfalfa land was two times more than that in vineyard. Results showed that 44.5% of T-P in native land was stored in surface layer; besides, the portion of the arable surface horizon in T-P sequestration was 33%.     

Modeling the relationship between the main emulsion components and stability, viscosity, fluid behavior, zeta-potential, and electrophoretic mobility of orange beverage emulsion using response surface methodology

The possible relationships between the main emulsion components (namely, Arabic gum, xanthan gum, and orange oil) and the physicochemical properties of orange beverage emulsion were evaluated by using response surface methodology. The physicochemical emulsion property variables considered as response variables were emulsion stability, viscosity, fluid behavior, zeta-potential, and electrophoretic mobility. The independent variables had the most and least significant ( p < 0.05) effect on viscosity and zeta-potential, respectively. The quadratic effect of orange oil and Arabic gum, the interaction effect of Arabic gum and xanthan gum, and the main effect of Arabic gum were the most significant ( p < 0.05) effects on turbidity loss rate, viscosity, viscosity ratio, and mobility, respectively. The main effect of Arabic gum was found to be significant ( p < 0.05) in all response variables except for turbidity loss rate. The nonlinear regression equations were significantly ( p < 0.05) fitted for all response variables with high R (2) values (>0.86), which had no indication of lack of fit. The results indicated that a combined level of 10.78% (w/w) Arabic gum, 0.56% (w/w) xanthan gum, and 15.27% (w/w) orange oil was predicted to provide the overall optimum region in terms of physicochemical properties studied. No significant ( p > 0.05) difference between the experimental and the predicted values confirmed the adequacy of response surface equations.     

Ultra-fast separation of wheat glutenin subunits by reversed-phase HPLC using a superficially porous silica-based column

A relatively new, unique column packing material for reversed-phase high-performance liquid chromatography (RP-HPLC) was evaluated for rapid separation of wheat glutenin protein subunits. The product named “Poroshell” by the manufacturer consists of a solid core and a porous coat instead of solid silica spheres used in conventional RP-HPLC column packing. This architecture favours rapid mass transfer, facilitating faster reversed-phase separations of biomolecules compared to conventional silica columns. The main objective of this study was to evaluate the quality of separations of glutenin subunits (GS), as well as to optimize conditions to produce the fastest possible run times without sacrificing resolution using a Poroshell 300SB-C₈ 2.1×75 mm column. The stability of GS separations over time was also assessed. Two different bread wheat genotypes were used for optimization of separation conditions and six more common and durum wheat genotypes possessing different subunit combinations were used for further evaluation. Glutenin protein was extracted with 0.08 M Tris–HCl buffer (pH 7.5) containing 50% 1-propanol under reducing conditions after pre-extraction of soluble proteins with 50% 1-propanol. Optimization of GS resolution and sample throughput by RP-HPLC was assessed in response to variation in eluent flow rate, acetonitrile (ACN) gradient, and column temperature. The best resolution of both HMW- and LMW-GS was obtained in 13 min using a 23–44% ACN gradient with a flow rate of 0.7 mL/min at 65 °C. Subunit elution times and integrated areas were highly repeatable even after several hundred injections. Highly satisfactory separation of HMW-GS and quantification of ratio of HMW- to LMW-GS were achieved in less than 4 min per sample using a modified HPLC gradient. Ratio of HMW- to LMW-GS was unaffected by the speed of the separations. As well, the elution order of HMW- and LMW-GS was unaffected by the rapid analysis, compared to conventional RP-HPLC separations, so no new learning was required for interpreting chromatograms and classification of subunits. The rapid RP-HPLC method using the Poroshell column appears to be very well suited for routine quantification of HMW-GS and LMW-GS especially for purposes of wheat quality screening and wheat cultivar development activities where large numbers of samples are typically encountered.     

Comparison between invasive and noninvasive tests in diagnosis of Helicobacter pylori infection

In this study, the invasive and noninvasive diagnotic tests were compared to choose the appropriate test for diagnostice of H. pylori infection. Helicobacter pylori (H. pylori) is a human pathogen that causes chronic gastritis, has a role in gastric and duodenal ulcer, is involved in gastric carcinogenesis and is regarded as a possible important factor in at least a subset of patients with functional dyspepsia. The diagnosis of H. pylori is an essential element in the management of many common gastrointestinal pathologies. The assessment of each routine invasive and noninvasive test is important. We studied a total of 127 outpatients for the detection of H. pylori infection. The presence of H. pylori infection by invasive tests containing the Rapid Urease Test (RUT), histology (Giemsa staining) and culture in 127 patients. Patients who were positive in culture, or two tests from four tests, invasive and noninvasive, were considered to have H. pylori infection. In noninvasive tests, we evaluated anti-H. pylori IgG and anti-CagA antibodies using commercial Enzyme-Linked Immunoassay (ELISA) and Western blot in dyspeptic patients. Eighty five out of the 127 patients were positive for H. pylori. Helicobacter pylori IgG seropositivity and 35 out of the 127 patients were positive for immunoblot. RUT had sensitivity, specifity and accuracy of 96, 80 and 90.5%, respectively; for Elisa these were 85.2, 33 and 70.5%, respectively and for ELISA with immunoblotting they were 65, 45 and 58.8%, respectively. The results of this study suggest that noninvasive tests (ELISA, immunoblotting) have the lowest and RUT with histology have the highest accuracy. These earlier tests can not be used for accurate infection diagnosis.     

Ultraviolet light and semi‐recirculating systems in artificial incubation of noble crayfish (Astacus astacus) eggs: opportunities and limitations

Development of artificial crayfish egg incubation is a milestone in intensive culture of crayfish as commercially important freshwater animals. This study evaluated experimental treatments combining continuous UV lighting, a non‐chemical antifungal treatment, with an initial formaldehyde bath for noble crayfish (Astacus astacus) eggs incubated in semi‐recirculating systems, which requires less than 1 per cent the amount of water necessary for conventional flow‐through systems. The one‐time administration of a pre‐incubation bath to reduce formaldehyde exposure was ineffective. Ultraviolet irradiation of recirculating water provided poor results (13.5% and 35.2% final survival rates to stage 2 juveniles) and led to deteriorating water quality. An inability of hatchlings to successfully moult and the occurrence of limb deformities was observed in UV‐treated groups, and juvenile mortality was found across all experimental treatments.     

IL-4, IL-5 and IFN-gamma mRNA expression in pulmonary lymphocytes in equine heaves

Heaves is a common condition of horses of cold climate that is characterized by small airway inflammation and obstruction following exposure of susceptible horses to moldy hay and straw. It has been shown that helper T lymphocytes (Th) orchestrate the inflammatory response in asthma and in various animal models of allergic lung diseases by the release of Th2-type cytokines. Results of previous studies indicate that a predominant expression of Th2-type response by airway cells may also be present in heaves. To evaluate the temporal mRNA expression of Th1 (IFN-gamma) and Th2 (IL-4, IL-5) type cytokines in heaves and their relationship to clinical disease, we studied the pulmonary mechanics and cytokine mRNA expression (IL-4, IL-5 and IFN-gamma) in bronchoalveolar lavage lymphocytes of horses with heaves (n=6) and control (n=6) before and after 24h and 9 days of continuous natural inhalation challenge. Starting 24h after challenge horses with heaves, but not control horses, had a significant increase in pulmonary elastance and the number of lymphocytes expressing mRNA for IL-4 and IL-5. These changes were further increased at 9 days, at which time the number of cells positive for IFN-gamma mRNA was decreased. In this study we have shown that BAL lymphocytes of horses with heaves during clinical exacerbation have a predominant Th2-type cytokine response and that this response coincides in time with the presence of airway obstruction.