Electrochemical Method for the Rapid on Site Screening of Cadmium and Lead in Soil and Water Samples

Rapid field-based screening methods for the semi-quantitative determination of heavy metals are desirable to support the increasing demand for the rapid characterization of contaminated sites. Single-use sensors have been fabricated using low-cost screen-printing (thick film) technology. These electrodes, coupled with differential pulse anodic stripping voltammetry (DPASV), have provided a rapid, inexpensive on site screening device for the simultaneous field-based determination of cadmium (Cd) and lead (Pb) in soil and water samples in the microgram per litre/kilogram range. A simplified soil extraction procedure, using 1 mol l^?1 aqua regia and a 3 min ultrasonic sample agitation, has been developed to allow field-based device usage. Extraction efficiency was evaluated using a soil certified reference material (CRM). Recoveries of 64% and 52% for Cd and Pb respectively were obtained, with a relative standard deviation (RSD) of <8% for both analytes (n = 10). Soil samples (82) were tested using the combined extraction-DPASV procedure and compared against standard ICP-AES analysis. Correlation coefficients of 0.9782 and 0.9728 for Cd and Pb respectively demonstrate good correlation between methods. Analytical data is also reported for copper (Cu), but significant peak distortions reduce the confidence of the method for this metal. Results indicate that the combined extraction-DPASV method yields semi-quantitative data for rapid field-based site screening purposes.     

Wound‐healing potential of curcumin in the carp,Labeo rohita

In this investigation, the effect of dietary administration of curcumin on the healing of skin wound in fish, Labeo rohita, has been reported. Fish were divided into three groups: control group (fish without skin wound), sham group (fish with skin wound without curcumin treatment) and curcumin‐treated group (fish with skin wound and subjected to dietary administration of 1% curcumin). Experiments were conducted for 30 days to assess the healing of skin wounds at different time intervals using scanning electron microscopy, histology, and mucopolysaccharide and enzyme histochemistry. In the curcumin‐treated group, healing of skin wounds was found to be enhanced than in the sham group as indicated by early restoration of morphology of the surface layer of epithelial cells; the density of the mucous goblet cells; the density of club cells in epidermal layer; and early granular tissue formation, collagen deposition and tissue remodelling in dermal layer. Furthermore, peroxidase and catalase enzyme activity showed increased endogenous defence system in the curcumin‐treated group compared with the sham group. It could be concluded that dietary administration of curcumin is beneficial in rapid healing of skin wounds in fish. Early healing of wounds could be considered to prevent the invasion of pathogens and to maintain the integrity of the surrounding tissue.     

Effect of elevated carbon dioxide on growth,nutrient partitioning,and uptake of major nutrients by soybean under varied nitrogen application levels

Rising carbon dioxide (CO₂) concentration causes fertilization effects resulting in enhanced crop biomass and yields and thus likely enhances nutrient demand of plants. Hence, this field study was carried out to investigate the effects of elevated CO₂ and N on biomass yield, nutrient partitioning, and uptake of major nutrients by soybean (Glycine max L.) using open‐top chambers (OTCs) of 4 m × 4 m size. Soybean was grown in OTCs under two CO₂ [ambient and elevated (535 ± 36.9 mg L^?1)] and four N levels during July to October 2016. The four N levels were N₀, N₅₀, N₁₀₀, and N₁₅₀ referring to 0, 50, 100, and 150% recommended dose of N. Both CO₂ and N significantly affected biomass and grain yield, though the interaction was non‐significant. CO₂ enrichment produced 30–65% higher biomass and 26–59% higher grain yield under various N levels. As compared to the optimum N application (N₁₀₀), the CO₂‐mediated increment in biomass yield decreased with either lower or higher N application, with the response being lowest at N₁₅₀. As compared to ambient concentration, elevated CO₂ resulted in significant reduction of seed P concentration at all N application levels but at N₁₅₀, an opposite trend was observed. The decrease in seed P was maximum at N₀ and N₅₀ (7–9%) and by 3% at N₁₀₀, whereas there was a gain of 7.5% at N₁₅₀. The seed N and K concentrations were not affected either by CO₂ or N application. Total N, P, and K uptake at harvest were significantly affected by CO₂ and N, but not by CO₂ × N interaction. Elevated CO₂ resulted higher uptake of N by 18–61%, P by 23–62%, and K by 22–62% under various N treatments.     

Relationship Between Physicochemical Properties of Wheat Flour,Wheat Protein Composition,and Textural Properties of Cooked Chinese White Salted Noodles

Physicochemical properties and protein composition of 39 selected wheat flour samples were evaluated and correlated with the textural properties of Chinese hard‐bite white salted noodles. Flour samples were analyzed for their protein and wet gluten contents, sedimentation volume, starch pasting properties, and dough mixing properties by farinograph and extensigraph. Molecular weight distribution of wheat flour proteins was determined with size‐exclusion (SE) HPLC, SDS‐PAGE, and acid‐PAGE. Textural properties of Chinese hard‐bite white salted noodles were determined through texture profile analysis (TPA). Hardness, springiness, gumminess, and chewiness of cooked noodles were found to be related to the dough mixing properties. Both protein content and protein composition were found to be related to TPA parameters of noodles. The amount of total flour protein was positively correlated to hardness, gumminess, and chewiness of noodles. The absolute amounts of different peak proteins obtained from SE‐HPLC data showed positive correlations with the hardness, gumminess, chewiness, and springiness of noodles. The proportions of these peak proteins were, however, not significantly related to texture parameters. The proportions of low‐molecular‐weight glutenins/gliadins and albumins/globulins, as observed from SDS‐PAGE, were correlated positively and negatively, respectively, to the hardness, gumminess, and chewiness of cooked noodles. Among the alcohol‐soluble proteins (from acid‐PAGE data), β‐gliadins showed strong correlations with the texture properties of cooked noodles. For the selected flour samples, the total protein content of flour had a stronger relationship with the noodle texture properties than did the relative proportion of different protein subgroups. Prediction equations were developed for TPA parameters of cooked noodles with SE‐HPLC and rapid visco analysis data of the 30 flour samples, and it was found that about 75% of the variability in noodle hardness, gumminess, and chewiness values could be explained by protein composition and flour pasting properties combined together. About 50% of the variations in cohesiveness and springiness were accounted for by these prediction equations.