A modified sequential extraction method for arsenic fractionation in sediments

A modified sequential extraction method was developed to characterize arsenic (As) associated with different solid constituents in surficial deposits (sediments), which are unconsolidated glacial deposits overlying bedrock. Current sequential extraction methods produce a significant amount of unresolved As in the residual fraction, but our proposed scheme can fractionate >90% of the As present in sediments. Sediment samples containing different As concentrations (3–35 μg g⁻¹) were used to assess the developed method. The pooled amount of As recovered from all the fractions using the developed method was similar (83–122%) to the total As extracted by acid digestion. The concentrations of As in different fractions using the developed scheme were comparable (89–106%) to the As fractions obtained by other existing methods. The developed method was also evaluated for the sequential extraction of other metals such as copper (Cu), cobalt (Co), chromium (Cr) and strontium (Sr) in the sediment samples. The pooled concentrations of these four individual metals from all the fractions were similar (96–104%) to their total concentrations extracted by acid digestion. During method development, we used extractants that did not contain chloride to eliminate formation of polyatomic ions of argon chloride (⁴⁰Ar³⁵Cl) that interfered with ⁷⁵As when analyzed using inductively coupled plasma mass spectrometer (ICP-MS). The results suggest that the developed method can reliably be employed for complete As and other metals’ fractionation in sediments using ICP-MS.     

Viscosity Mixing Rules for Binary Systems Containing One Ionic Liquid

In this work the applicability of four of the most commonly used viscosity mixing rules to [ionic liquid (IL)+molecular solvent (MS)] systems is assessed. More than one hundred (IL+MS) binary mixtures were selected from the literature to test the viscosity mixing rules proposed by 1) Hind (Hi), 2) Grunberg and Nissan (G–N), 3) Herric (He) and 4) Katti and Chaudhri (K–C). The analyses were performed by estimating the average (absolute or relative) deviations, AADs and ARDs, between the available experimental data and the predicted ideal mixture viscosity values obtained by means of each rule. The interaction terms corresponding to the adjustable parameters inherent to each rule were also calculated and their trends discussed.     

Fingerprint image enhancement using data driven Directional Filter Bank

A new method based upon data driven tool, principal component analysis (PCA), for fingerprint enhancement is proposed in this paper. PCA is a very useful statistical technique that has found application in many different fields like image compression, face recognition and is commonly used for finding patterns in data of high dimension. In the proposed method, the input image is first decomposed into directional images using decimation free Directional Filter Bank (DDFB). Then these directional images are normalized. A data driven technique PCA is applied to these normalized directional fingerprint images, which gives the PCA filtered images. These are basically directional images. Then these directional images are reconstructed into one image which is the enhanced one. Simulation results are included illustrating the capability of the proposed method.     

Enolesters as chain end-functionalizing agents for the living ring opening metathesis polymerization

Functional enolethers have previously been used to introduce functional end groups at the chain end of ruthenium carbene complex initiated living ring opening metathesis polymers. Here, we investigated whether the weaker π-donating enolesters could equally be used in regio selective reactions with ruthenium carbene complexes and thus as polymer end-functionalization reagents. Enolesters such as vinyl acetate, butenyl acetate, 3-(4-(tert-butoxy)phenyl)propenyl acetate and 6-(((benzyloxy)carbonyl)amino)hex-1-en-1-yl acetate were used as living ROMP terminating agents. All gave the expected end groups proving that enolesters are synthetically easily accessible targets for living ROMP end-functionalization. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 2983–2990     

Synthesis,spectroscopic characterization,X-ray crystal structure,biological screening and catalytic studies of organotin(IV) carboxylates of 3-(4-cyanophenyl) acrylic acid

A series of six organotin(IV) carboxylates [Me₂SnL₂] (1), [n-Bu₂SnL₂] (2), [n-Oct₂SnL₂] (3), [Me₃SnL] (4), n-Bu₃SnL (5) and [Ph₃SnL] (6), where L = 3-(4-cyanophenyl) acrylic acid have been synthesized and characterized by elemental analysis, FT-IR and NMR (¹H, ¹³C). The complex (4) was also analyzed by single crystal X-ray analysis which showed distorted trigonal bipyramidal geometry with polymeric bridging behavior. The complexes 1–6 were screened for antimicrobial activities and cytotoxicity. The results showed significant activity with few exceptions. The catalytic activity of complexes was assessed in transesterification reaction of Brassica campestris oil (triglycerides) to produce biodiesel (fatty acid methyl esters). The results showed that triorganotin(IV) complexes exhibited good catalytic activity than their di-analogues.     

Selenium Alleviates the Adverse Effect of Drought in Oilseed Crops Camelina (Camelina sativa L.) and Canola (Brassica napus L.)

Drought poses a serious threat to oilseed crops by lowering yield and crop failures under prolonged spells. A multi-year field investigation was conducted to enhance the drought tolerance in four genotypes of Camelina and canola by selenium (Se) application. The principal aim of the research was to optimize the crop yield by eliciting the physio-biochemical attributes by alleviating the adverse effects of drought stress. Both crops were cultivated under control (normal irrigation) and drought stress (skipping irrigation at stages i.e., vegetative and reproductive) conditions. Four different treatments of Se viz., seed priming with Se (75 μM), foliar application of Se (7.06 μM), foliar application of Se + Seed priming with Se (7.06 μM and 75 μM, respectively) and control (without Se), were implemented at the vegetative and reproductive stages of both crops. Sodium selenite (Na₂SeO₃), an inorganic compound was used as Se sources for both seed priming and foliar application. Data regarding physiochemical, antioxidants, and yield components were recorded as response variables at crop maturity. Results indicated that WP, OP, TP, proline, TSS, TFAA, TPr, TS, total chlorophyll contents, osmoprotectant (GB, anthocyanin, TPC, and flavonoids), antioxidants (APX, SOD, POD, and CAT), and yield components (number of branches per plant, thousand seed weight, seed, and biological yields were significantly improved by foliar Se + priming Se in both crops under drought stress. Moreover, this treatment was also helpful in boosting yield attributes under irrigated (non-stress) conditions. Camelina genotypes responded better to Se application as seed priming and foliar spray than canola for both years. It has concluded that Se application (either foliar or priming) can potentially alleviate adverse effects of drought stress in camelina and canola by eliciting various physio-biochemicals attributes under drought stress. Furthermore, Se application was also helpful for crop health under irrigated condition.     

Methoxy-Substituted Tyramine Derivatives Synthesis,Computational Studies and Tyrosinase Inhibitory Kinetics

Targeting tyrosinase for melanogenesis disorders is an established strategy. Hydroxyl-substituted benzoic and cinnamic acid scaffolds were incorporated into new chemotypes that displayed in vitro inhibitory effects against mushroom and human tyrosinase for the purpose of identifying anti-melanogenic ingredients. The most active compound 2-((4-methoxyphenethyl)amino)-2-oxoethyl (E)-3-(2,4-dihydroxyphenyl) acrylate (Ph9), inhibited mushroom tyrosinase with an IC₅₀ of 0.059 nM, while 2-((4-methoxyphenethyl)amino)-2-oxoethyl cinnamate (Ph6) had an IC₅₀ of 2.1 nM compared to the positive control, kojic acid IC₅₀ 16700 nM. Results of human tyrosinase inhibitory activity in A375 human melanoma cells showed that compound (Ph9) and Ph6 exhibited 94.6% and 92.2% inhibitory activity respectively while the positive control kojic acid showed 72.9% inhibition. Enzyme kinetics reflected a mixed type of inhibition for inhibitor Ph9 (K_i 0.093 nM) and non-competitive inhibition for Ph6 (K_i 2.3 nM) revealed from Lineweaver–Burk plots. In silico docking studies with mushroom tyrosinase (PDB ID:2Y9X) predicted possible binding modes in the catalytic site for these active compounds. Ph9 displayed no PAINS (pan-assay interference compounds) alerts. Our results showed that compound Ph9 is a potential candidate for further development of tyrosinase inhibitors.     

Exogenous Sodium Nitroprusside Mitigates Salt Stress in Lentil (Lens culinaris Medik.) by Affecting the Growth,Yield, and Biochemical Properties

Soil salinity disrupts the physiological and biochemical processes of crop plants and ultimately leads to compromising future food security. Sodium nitroprusside (SNP), a contributor to nitric oxide (NO), holds the potential to alleviate abiotic stress effects and boost tolerance in plants, whereas less information is available on its role in salt-stressed lentils. We examined the effect of exogenously applied SNP on salt-stressed lentil plants by monitoring plant growth and yield-related attributes, biochemistry of enzymes (superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD)) amassing of leaf malondialdehyde (MDA) and hydrogen peroxide (H₂O₂). Salinity stress was induced by NaCl application at concentrations of 50 mM (moderate salinity) and 100 mM (severe salinity), while it was alleviated by SNP application at concentrations of 50 µM and 100 µM. Salinity stress severely inhibited the length of roots and shoots, the relative water content, and the chlorophyll content of the leaves, the number of branches, pods, seeds, seed yield, and biomass per plant. In addition, MDA, H₂O₂ as well as SOD, CAT, and POD activities were increased with increasing salinity levels. Plants supplemented with SNP (100 µM) showed a significant improvement in the growth- and yield-contributing parameters, especially in plants grown under moderate salinity (50 mM NaCl). Essentially, the application of 100 µM SNP remained effective to rescue lentil plants under moderate salinity by regulating plant growth and biochemical pathways. Thus, the exogenous application of SNP could be developed as a useful strategy for improving the performance of lentil plants in salinity-prone environments.