Electrochemical studies of Zn underpotential/overpotential deposition on a nickel electrode from non-cyanide alkaline solution containing glycine

In this work we present an electrochemical study of the underpotential deposition (UPD) and overpotential deposition (OPD) of zinc onto nickel electrode (NE) from a non-cyanide alkaline solution containing glycine. The studied parameters were zinc concentration, glycine concentration and scanning rate. The analysis of the experimental data clearly showed the presence of UPD and OPD processes that started at −0.8 V vs. SCE and −1.4 V vs. SCE, respectively. The voltammetric studies also indicate diffusion control of the zinc UPD and OPD processes onto the NE. From the potentiostatic transients we found instantaneous nucleation (2D) mechanisms, which agree to that observed in the AFM study. In order to compare the effect of zinc/glycine concentration, we calculate thermodynamic parameters for the OPD process.     

Engineering proteolytically-degradable artificial extracellular matrices

Hydrogels are widely used as provisional matrices for tissue engineering and regenerative medicine, showing also great promise as platforms for 3D cell culture. Different bio-functionalization strategies have been proposed to enhance the biological performance of hydrogels, particularly when they lack intrinsic bioactivity. In this context, the design of artificial materials that mimic structural and functional features of the natural extracellular matrix (ECM) has been pursued. This review presents an overview on bioengineering approaches of integrating protease-sensitive motifs into hydrogels, for the creation of cell-responsive biomimetic scaffolding materials that degrade in response to their proteolytic microenvironment. The successful incorporation of protease-sensitive motifs in several synthetic and natural polymers, which has been achieved using various chemical routes, is described. In each case, the selected peptide sequences and their target proteases are highlighted, along with the main achievements of the study. A critical analysis of current limitations and recent advances is also provided, along with suggestions for further improvements.     

Effects of using wind exhausters on the quality and cost of soybean storage on a real scale

The objective of this study was to evaluate the effects of the wind exhaustion system (with and without natural lighting) during soybean storage (0, 3, and 6 months) on energy cost, mass temperature, mass loss, and soybean quality. During storage, the silo without exhaustion required more hours of aeration (191 h), higher energy consumption (9550 kW), and showed higher reduction in moisture content (2.07%) and loss of mass (105 t), when compared to silos with exhaustion and light and with exhaustion and no light. Fermented and moldy defects increased during storage, with a higher incidence of mold in the silo with exhaustion and no light when compared to the silo without exhaustion. Germination and soluble protein decreased during storage, but no difference was observed between silos. The acidity increased during storage, with the higher acidity being found in the silo with exhaustion and light when compared to the silo without exhaustion. The silo with exhaustion and light had an increase in electrical conductivity during storage, however, the lower electrical conductivity in 6 months was observed in the silo without exhaustion. The yellow coloration (b*-value) and the luminosity (L*-value) of the grains decreased during storage in silos with exhaustion and light and in the silo with exhaustion and no light. All silos had good conservability during storage, with acceptable values in all analyzed parameters. The excess of aeration promoted the soybean drying to safer levels of storage in the silo without exhaustion, however, the cost of storage was higher in that silo.     

Deposition of Zn–Cr alloy coatings from sulfate electrolyte: effect of polypropylene glycol 620 and glycine and combinations thereof

The effect of polypropylene glycol with molecular mass 620 (PPG 620) and glycine as additives in electrodeposition of Zn–Cr alloy coatings from acidic sulfate electrolyte containing (NH₄)₂SO₄ and H₃BO₃, at ambient temperature, without agitation is investigated. PPG 620 inhibits the Zn reaction causing significant proximity of the deposition potentials of Zn and Cr, and a co-deposition at a less negative potential of ?1.8 V (vs. Hg/Hg₂SO₄) as compared to the case when polyethylene glycol 1500 (PEG 1500) is used. Depending on the deposition conditions, alloy coatings containing up to 23 mass % Cr can be obtained. Glycine itself does not facilitate the co-deposition of Cr and Zn. Added to the electrolyte containing PPG 620, glycine causes a decrease of the Cr content in the alloy. However, the alloy coatings deposited in the presence of both additives are denser, have better overall appearance and good adherence to the steel substrate. Moreover, glycine increases the buffer capacity of the electrolyte. At short deposition times, the alloy coatings consist mainly of bcc Γ _x -(Zn, Cr) phase with lattice parameter about 3.035 (3) Å and mean crystallite size of the order of 25 nm. Cr content in the coatings can be controlled by changing the concentration of Cr(III) and pH of the electrolyte as well as the current density. Depending on the working conditions, the cathode current efficiency is within 35–55%.     

Optimization of extraction and isolation for 11S and 7S globulins of soybean seed storage protein

A new method was developed for extraction and isolation of 7S and 11S fractions from soybean seed, based on methods of Nagano et al., Thanh and Shibasaki [Nagano, T., Hirotsuka, M., & Mori, H. (1992). Dynamic viscoelastic study on the gelation of 7S globulin from soybeans. Journal of Agricultural and food chemistry 40, 941–944 and Thanh, V. H., & Shibasaki, K. (1976). Major proteins of soybean seeds. A straightforward fraction and their characterization. Journal of Agricultural and Food Chemistry 24, 1117–1121]. Optimization of the extraction and isolation of 11S and 7S globulins from soybean seed was investigated under various conditions by the Kjeldahl method and SDS-PAGE. The optimal conditions were as follows: 0.03–0.06 M Tris–HCl buffer (pH 8.5) containing 0.01 M sodium bisulfite as extract solution, extraction twice at 45 °C for 1 h, and with a 1:15 ratio (w/v) of flour:Tris–HCl. The 11S fraction was precipitated at pH 6.4, and the supernatant, after centrifugation, was adjusted to pH 5.5 to remove the insoluble intermediate fraction by further centrifugation. The supernatant obtained was then adjusted to pH 4.8 to afford the 7S fraction as a precipitate by centrifugation. With the improvements, the protein contents and purities of the isolated 11S and 7S fractions were significantly increased. The contents of all subunits of the isolated 11S and 7S fraction were markedly higher than those by Thanh and Shibasaki method, while the contents of α, β and B₃ were also significantly higher than those by Nagano et al. method.     

Properties of Cu,Ni, and V doped-LaCrO <Subscript>3</Subscript> interconnect materials prepared by pechini,ultrasonic spray pyrolysis and glycine nitrate processes for SOFC

The ceramic interconnect,La_0.8Sr_0.05Ca_0.15(Cr_{1 −x} , B_x)O₃ (B = Cu, Ni, V, x = 0.02, 0.1, 0.5) (LSCCB) powders were prepared by Pechini method, Ultrasonic Spray Pyrolysis (USP) and Glycine Nitrate Process (GNP). Nano sized powders were synthesized by GNP and their chemical compositions were confirmed by ICP analysis. The electrical conductivities of LSCCCu, LSCCNi, and LSCCV samples were 34 S/cm, 48 S/cm, and 22 S/cm at 800^∘C in air, respectively. Among the LSCCB powders, the LSCCNi sample shows highest relative density and electrical conductivity. In a low oxygen partial pressure, however, LSCCV sample was more stable. The perovskite phase of the composition LSCCV sample is of large practical interest for interconnects in SOFC because of the stability in low oxygen partial pressure.     

低磷胁迫对大豆根系生长特性及分泌H~＋和有机酸的影响

以不同基因型大豆nf37和冀黄13为材料,溶液培养法研究大豆根系周围的酸化现象,并通过对大豆根干重、根冠比以及植株中磷含量的测定来探讨不同基因型大豆对枸溶性磷肥的利用效率。结果表明,低磷胁迫下,不同基因型大豆的根系均能主动向外界环境分泌H＋;经HPLC分析得出,柠檬酸、草酸、酒石酸和苹果酸是主要分泌的有机酸;当向培养介质中添加枸溶性磷肥后,不同基因型大豆均可有效利用这一难溶性磷肥。无论是H＋分泌量、有机酸分泌量还是对枸溶性磷肥的利用效率,耐低磷基因型大豆（nf37）都显著高于磷敏感基因型大豆（冀黄13）。表明,低磷胁迫均导致不同基因型大豆根系向介质中分泌H＋和有机酸,同时还诱导大豆根系的加速生长,各项指标在耐低磷和磷敏感大豆基因型之间表现出显著差异,这可能是不同基因型大豆对枸溶性磷肥吸收、利用效率不同的原因。     

An investigation of fuel precursors and calcination temperature to obtain mayenite (Ca12Al14O33) powders by solution combustion synthesis

The influence of the fuel (glycine, urea, citric acid and sucrose) and calcination temperature used to obtain calcium aluminate in the mayenite phase assisted by solution combustion synthesis (SCS) is the central point of this work. Thermal gravimetric analysis helps to establish the calcination temperatures used (1100, 1200 and 1300 °C). Using the X-ray diffraction technique (XRD) and complementary analyses, such as Raman spectroscopy, the specific surface area and laser granulometry, it was possible to elucidate the behavior and relationship of the fuel and heat treatment on the phase formation, crystallite size and powder crystallinity. Glycine showed better performance than other fuels, with the lowest calcination temperature, obtaining pure mayenite with nanometric crystallite size in all calcination ranges. Thus, it was observed that the type of fuel has an influence on obtaining pure mayenite, as well as the calcination temperature, and glycine reveals the best performance.     

Exploring seed and meal composition and protein solubility in soybean genotypes from different domestication periods

Traditionally, commercial soybean breeding has focused on increasing seed yield by crossing elite cultivars and limiting the genetic diversity within commercial germplasm. Wild and ancestral soybean genotypes have higher seed protein concentrations than commercial ones. Different seed protein concentrations and compositions result in diverse functional properties of soybean meal, in particular solubility is important for beverages and protein isolates production. The objectives of our study were (i) to characterize seed protein concentration and composition in genotypes from different soybean domestication periods (types) and (ii) to evaluate the protein concentration and solubility profiles of the defatted meals obtained from these genotypes. Variation within seed and meal protein concentration, composition, and solubility was evident along the domestication process. Wild relative (G. soja) and Elite genotypes had the maximum and minimum seed protein concentrations, respectively (42.9 and 36.3 g 100 g⁻¹). Soybean meal protein concentrations were 55.1, 47.7, 48.4 and 44.1 g 100 g⁻¹ for Wild relative (G. soja), Asian landraces, North American (Nam) ancestors and Elite, respectively. Ample genotypic variation was observed for β-conglycinin components, such as for β, α, and α′ subunits and for total glycinin and its components. Asian landraces had the highest protein solubility. Wild and ancestral germplasm are a reservoir of useful traits to improve soybean seed quality. This study opens the gates to the introduction of ancestral germplasm to breeding programs focused on protein quality and functionality.