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关键词： NPs   H2O2   Yb2O3   Cyclic voltammetry   Current   Potential  

摘要： Herein, a uniform spherical shaped Gd(III) doped Yb2O3 (Gd@Yb2O3) nanoparticles (NPs) was successfully synthesized via hydrothermal method for electrochemical detection of H2O2. The calcination effect and porosity of the materials well elaborated in the present work. The optical properties, size, morphological, thermal, sensing, surface and crystalline properties of synthesized materials were examined by several techniques. The enhanced electrocatalytic performance of Gd@Yb2O3 make the present sensor excellent towards the determination of *** anodic and cathodic peak current increased regularly with addition of H2O2 solution. The electrode coating surface was stable even after a number of electrochemical cycles and have high limit of detection (51 nM). Moreover, the present sensor was successfully employed for detection of H2O2 in real samples.

关键词： Protein   Benzoic acid   Stability   Solvent accessibility   Molecular dynamics calculations  

摘要： Carboxyl-modified substrates are the most common chemical moieties that are frequently used as protein defibrillators. We studied the stability of protein-benzoic acid complexes with bovine serum albumin (BSA), zein and lysozyme proteins using various computational methods. Structural model for zein was built using homology modelling technique and molecular docking was used to prepare complex structures of all three proteins with benzoic acid. Molecular dynamics calculations performed on these complex structures provided a strong support for the stability of protein-benzoic acid complexes. The results from various analyses including root-mean-square deviation (RMSD) and radius of gyration showed the stability and compactness of all proteins-benzoic acid complexes. Moreover, exploration of structural fluctuations in proteins revealed the stability of active site residues. Two potential binding modes of benzoic acid with all three proteins were identified via cluster analysis. The binding mode which was retrieved from top cluster containing 86-91% of total conformations displayed very strong binding interactions for zein, BSA and lysozyme proteins. In addition, the results of binding mode showed that various interactions, including hydrogen binding, hydrophobic and electrostatic interactions were important for the optimal binding of benzoic acid with the active sites of proteins. Exploration of solvent accessible surface area showed that lysozyme-binding cavity was more exposed to the surface as compared to the other two proteins. Free energy analysis of all protein systems showed the stability of protein-benzoic acid complexes with lysozyme and BSA relatively more stable than zein system. The results of our study provided important insights to the dynamic and structural information about protein-benzoic acid interactions with BSA, zein and lysozyme proteins. This work is important in enhancing the stability of therapeutic protein drugs loaded on carboxyl substrates.

关键词： Secondary metabolites   Soil quality   Ocimum   Bioactivity  

摘要： Ocimum has long been used as a medicinal plant, although little information is available about its bioactive ingredients, and the influence of soil properties on modulation of secondary metabolites in Ocimum has yet to be ascertained. In this study, we present a thorough survey of all potential metabolic compounds in O. sanctum and O. basilicum. In both species, certain compounds (e.g., quercetin, kaempferol, catechin, and S-adenosyl homocysteine) were detected coincidently. In the case of O. basilicum, other vital phenolic acids (e.g., ursolic, vanilic, coumaric, and syringic acids) were identified. The aqueous extracts (AEs) of Ocimum recorded decrease of 6-94% in the proliferation of pathogenic bacteria (e.g., Listeria monocytogenes, Staphylococcus sp., Salmonella sp., and Bacillus sp.). The AEs also showed effective antioxidant activity by reducing free radicals by a factor of 1.04-1.13. Root-zone soil samples of both Ocimum spp. were collected from strategic locations with varying levels of key soil attributes (e.g., soil organic carbon (SOC), microbial biomass carbon (MBC), urease, and phosphatase). At high levels of SOC, MBC, and soil enzymes, the bioactivity of Ocimum spp. was observed to be promoted, especially with respect to secondary metabolite expression, anti-pathogenic activity, and anti-oxidant properties. As such, the findings of strong correlations between secondary metabolite concentrations and bioactivity attributes in Ocimum suggest the potent role of soil quality in eliciting the production of secondary metabolite in association with bioactivity in Ocimum spp.

关键词： PCM   TRC   Composite material   Mechanical behaviour   Physicochemical investigation  

摘要： The present paper presents a multiscale and multiphysics study that focuses on the development of an innovative composite material, which combines a cementitious matrix modified by a phase-change material (PCM) with textile reinforcement (PCM-TRC). The development of this composite has been guided by the conjunction of several factors, among which it is appropriate to emphasise the lightweight of the composite due to the reduced covers in textile reinforced concrete (TRC) coupled to the high thermal inertia due to the addition of PCM microcapsules. This research focuses on the effect of PCM on the mechanical and physicochemical properties of TRC. Special emphasis is placed on providing the phenomenological explanation for the resulting mechanical behaviour of TRC according to the rate and state of the PCM. It has been found that the ductile mechanical behaviour of TRC composites is maintained in the presence of microencapsulated PCM;however, the mechanical performance of PCM-TRC decreases with the PCM rate. This is due to the disorder caused by PCM at the matrix and interface scales. Furthermore, it has been found that the PCM state (solid or liquid) can affect the mechanical performance of both the PCM-mortar matrix and PCM-TRC composite. This is due to PCM expansion during phase change from the solid to the liquid state, which can induce matrix microcracking.

关键词： pearling fraction   physicochemical properties   protein   protein conformation   wheat  

摘要： Backgrounds and objectives The protein from various parts of the wheat kernel has different physicochemical properties, which is one of the reasons for the different processing characteristics of the corresponding flour made from these parts. In this study, wheat kernels were pearled into seven fractions from the outermost to the innermost layers to evaluate the quantitative and conformational properties of protein fractions from different pearling fractions. Findings The crude protein and protein fraction content was lower in the corresponding pearling fractions that were closer to the center of the endosperm. The albumin and SDS-soluble protein contents in the total protein from the pearling fractions exhibited a similar trend, whereas the dry gluten content exhibited an opposite trend. The average molar mass (M-w), polydispersity index (M-w/M-n), and density (rho) of the SDS-soluble protein were decreased, but there was no significant difference in theR(gz). And the G ' plateau values of glutenin macropolymer (GMP) were increased. Conclusions Protein conformation of the inner endosperm was looser than the other pearling fractions. Loose network wrapped more protein that led to the increased proportion of dry gluten. And it may increase aggregate entanglement that attributed to GMP became more elastic. Significance and novelty The changes in protein conformation in pearling fractions of wheat kernels further explained changes in physicochemical properties of protein from different pearling fractions.

关键词： Fish   Shellfish   Muscle proteins   Stability   Structure   Characterization   Physiological functions  

摘要： Fish and marine invertebrates constitute an important part of the human diet worldwide, and their muscles are the major edible parts. The muscles are a rich source of proteins, which in other terms determines the nutritional value and the quality of seafood products. Though the fish skeletal muscle proteins share many similarities with their mammalian counterparts, there exist great differences in their biological activity and structural stability. While the muscles of shellfish or aquatic invertebrates share many properties and general structural features with their vertebrate counterparts, they have unique characteristics. Therefore, understanding the biochemical and physicochemical properties of their major protein components is needed from the viewpoint of effective utilization of aquatic bioresources. Thus, in this review, we aimed to assemble the basis of such differences and also to understand the benefits of these proteins as the targets for studies on the structure-stability relationship of proteins.

关键词： Refrigeration  

摘要： Efforts have been made to extend the poor shelf life of cassava roots through low-temperature storage like refrigeration, but the effects of this onlafun(fermented cassava flour) had not been investigated. This study determined the chemical composition oflafunobtained from cassava roots refrigerated for 1-3 weeks and the physicochemical and sensory properties of its cooked paste. Refrigerated storage (4 degrees C) slightly reduced the whiteness oflafunand appearance of the cooked *** refrigerated cassava roots showed similar titratable acidity values (approx. 0.53%), but varying pH values (4.10-5.25). Carbohydrate was the major macro-component oflafun(approx. 84%), while calcium (40.13-60.11 mg/100 g), sodium (39.60-48.70 mg/100 g), magnesium (20.12-40.99 mg/100 g), and potassium (24.92-32.01 mg/100 g) were the major minerals. An increase in the swelling index and peak viscosity oflafunsuggests an alteration in starch composition due to refrigeration. Cooked paste fromlafunprepared from refrigerated cassava showed comparable quality with the control. Practical applications Refrigeration is a low-temperature method of preservation that could be used to reduce the rate of biochemical and microbiological changes during storage and hence to extend the shelf life of fresh and processed foods. This study demonstrates the possibility of extending the shelf life of cassava roots using refrigeration without significant changes in the properties oflafunand cooked paste obtained from the stored roots. Furthermore, refrigerated storage could be used by small-holder farmers through cooperatives and government interventions to store cassava roots for at least 3 weeks before use.

关键词： Macrolide lactone   Nanotechnology   Raman scattering   Skin-related autoimmune disorders   Stability testing  

摘要： Tacrolimus (TAC) or FK506 is a macrolide lactone isolated from the bacterial fermentation of Streptomyces tsukubaensis which belongs to the group of calcineurin inhibitors. Its main mechanism of action is to act on the immune system. In addition, this drug has been widely explored for skin disorders. However, TAC shows high molecular weight, high hydrophobicity, and low water solubility that can limit its ability to effectively permeate through the skin. Hence, it becomes imperative to develop a percutaneous drug delivery system for increasing its permeation in relation to the conventional ointment and for reducing the dose and the adverse effects as erythema, itching, and burning. Therefore, the aim of this work was to investigate the stability of colloidal suspensions of TAC-loaded poly(epsilon-caprolactone) (PCL) nanoparticles that were stored at room temperature for 120 days. In that sense, pH, particle size, polydispersity index (PDI), zeta potential, and Raman spectroscopy were performed. Significant decrease of pH (p < 0.05) occurred after 60 days for TAC-loaded nanoparticles prepared at high drug concentration (NC-3, 3 ***(-1)). Loaded formulation showed significant pH changes (p < 0.05 to p < 0.001) after 90 of experiment. Non-loaded nanoparticles revealed significant pH increase (p < 0.05) after 120 days. Particle size and PDI had no statistical difference (p> 0.05) during the time interval investigated. Zeta potential presented statistically significant difference (p < 0.05) only for TAC-loaded nanoparticles after 120 days. The results obtained from Raman spectroscopy showed the suitability of the technique on the evaluation of stability TAC-loaded PCL nanoparticles. The analysis of Raman results demonstrated that the degradation mechanism occurred mainly in amorphous domains of PCL and resulted in an increased polymer crystallinity. Taking all these into account, TAC-loaded nanoparticles had a suitable stability within 60 days of preparation and can be

关键词： Riverine network   Carbon metabolism   Bacterial production   Bacterial respiration   Nutrients   Rio Grande  

摘要： Although freshwater systems comprise a small portion of land surface, they play a pivotal role in landscape carbon (C) cycling. Carbon processing by heterotrophic bacteria is critical, contributing to ecosystem production and dissolved organic carbon (DOC) processing. Riverine bacterial C metabolism is related to a diversity of factors, including (1) physiochemical conditions and inorganic nutrient concentrations and (2) DOC quality and quantity;however, the relative importance of these factors in influencing C metabolism across arid fluvial networks remains equivocal. This study examined C metabolism by heterotrophic bacterioplankton in the Rio Grande drainage, an arid river network in Texas, USA. We examined spatial variation in physicochemical and inorganic nutrient conditions, bacterial C metabolism, and DOC lability across the drainage and assessed whether variation in bacterial C metabolism was more related to physicochemical-inorganic nutrient conditions or DOC quantity and lability. Across the drainage, hydrology and landscape position influenced physicochemical conditions, bacterial abundance, phytoplankton biomass, and bacterial C metabolism and the proportion of variation in bacterial C metabolism explained by physicochemical/inorganic nutrient and DOC quality-quantity gradients was approximately equal. Bacterial abundance and production were associated with greater NH(4)(+)and DOC concentrations and phytoplankton biomass, whereas bacterial respiration and growth efficiency were driven by DOC color and suspended particulate concentrations. Results indicate that aspects of bacterial C metabolism are influenced by different environmental factors related to autochthonous and allochthonous inputs to riverine systems, which has implications for C transformation, sequestration, and transport to the ocean.

关键词： digestibility   heat treatment   physiochemical   water caltrop starch  

摘要： Water caltrop has a high starch content and is a promising resource of starch in Asia. Starch can be divided into rapidly digestible starch (RDS), slowly digestible starch (SDS), and resistant starch (RS). Here, the effects of physical modification by microwave treatments, heat-moisture treatments, and pressure-heat treatments on the physiochemical and structural properties and on the in vitro digestibility of water caltrop starch is studied. The results show that, compared with native starch (NS), the solubility and swelling power of modified starch samples decrease with prolonged microwave and heat-moisture treatment. The infrared absorbance ratio at 1047 cm(-1)/1022 cm(-1) is decreased in starch samples modified by microwave treatment and pressure-heat treatment, the NS samples present a C-type crystalline pattern which changes into an A-type pattern upon microwave treatment. Water caltrop starch subjected to 50 s of microwave treatment has the highest amylose (48.78%), the highest crystallinity (42.95%), and the highest RS content (67.41%, uncooked and 48.91%, cooked). Water caltrop starch subjected to 3 h of heat-moisture treatment contains the highest SDS content (54.33%, uncooked and 60.11%, cooked).