Effect of Psychrotrophic Growth on the Milk Fat Fraction at Different Temperatures of Storage

The use of cooling, without using adequate hygienic practices in primary milk production, allows for the growth of psychrotrophic microorganisms that produce the thermoresistant lipases that give milk a rancid flavor. This study aimed to verify how the variation in temperature influences the lipolytic metabolism of the psychrotrophic organisms. Samples of raw milk were collected and submitted to laboratorial analysis as follows: psychrotrophic bacteria count, lipolytic bacteria count, and free fatty acids dosage. Each sample was divided into 3 aliquots and then incubated at 4, 8, and 12 °C, respectively. For each temperature, analyses were repeated after 12, 24, and 48 h of storage. Despite the psychrotrophs growth increase, according to temperature rise, the lipolytic metabolism was not consistent and presented the lower index at 8 °C, suggesting an intensification of the proteolytic compensatory activity at this temperature.     

Purification of β‐Galactosidase by Ion Exchange Chromatography: Elution Optimization Using an Experimental Design

β‐Galactosidase is an enzyme industrially used to hydrolyze milk lactose, generating dairy products destined for people intolerant to this sugar. Its importance is due to its galactosiltransferase activity. The effects of elution pH and salt gradient volume were evaluated for purification of β‐galactosidase by ion exchange chromatography using an experimental design and response surface techniques. The best conditions for purification of β‐galactosidase were pH 5.5 with an elution volume of 62.8 mL, obtaining a yield of 85.5 % and a 12‐fold increase in the purification factor in a one‐step chromatography process. Purification of β‐galactosidase by application of a single stage of ion exchange and evaluation of the important process parameters using an experimental design provided good results in the recovery and purification factor that could subsequently be scaled up.     

Kaempferol inhibits VEGF expression and in vitro angiogenesis through a novel ERK-NFκB-cMyc-p21 pathway

Kaempferol has been reported to reduce the risk of ovarian cancer, but the mechanism is not completely understood. In this study, we tend to expand our understanding on how kaempferol regulates VEGF expression and angiogenesis in ovarian cancer cells. We timed VEGF secretion, and studied in-vitro angiogenesis by kaempferol treatment. Gene expression was examined by qRT-PCR, ELISA, Western Blotting, or luciferase assay, and pathways were examined by manipulating genetic components with plasmid or siRNA transfection. It was found that kaempferol time-dependently inhibited VEGF secretion, and suppressed in-vitro angiogenesis. Kaempferol down-regulated ERK phosphorelation as well as NFκB and cMyc expression, but promoted p21 expression. Examination of relationship between these genes suggested a novel ERK-NFκB-cMyc-p21-VEGF pathway, which accounts for kaempferol's angioprevention effects in ovarian cancer cells. This data supplements our comprehension of the mechanisms behind kaempferol's biological influence in ovarian cancer cells, and better characterized kaempferol toward chemoprevention.     

Improving the nutritional and phytochemical compounds of a plant-based milk of sapucaia nut cake using block freeze concentration

The nutrient profile and the phytochemical composition of the sapucaia nut cake milk (SNCM) were evaluated after applying five consecutive stages of block freeze concentration (C1, C2, C3, C4 and C5). The profile of phenolic compounds by LC-ESI-MS/MS and the antioxidant activity (ABTS and FRAP) of SNCM were also determined. The freeze concentration increased proteins, lipids, carbohydrates, ash, soluble solids (°Brix) and total phenolic compounds (TPC) in all stages and in the ice fractions obtained from C1, C2 and C3 stages. The antioxidant activity (ABTS) in C3, C4 and C5 fractions was highly significant (P < 0.05). The antioxidant activity (FRAP) and the phenolic compounds (gallic, vanillic, ferulic, sinapic and salicylic acids, catechin, taxifolin and sinapaldehyde) increased significantly (P < 0.05) for all five fractions. The freeze concentration was successfully used for enriching the SNCM, generating a promising ingredient for the food industry.     

Microstructure and mechanical properties of a rapid solidified boron- modified duplex stainless steel

Two duplex stainless steels 2205 and 2205 with 2.5?wt-% B addition prepared by a fast solidification technique were investigated. The samples were arc melted and cast in a cylindrical mould with varying diameters in a single cavity that provided different cooling rates. The hardness increased in both cases for smaller diameters, however, there was a different profile from the surface to the centre in case of 2205 with 2.5?wt-% B. The microstructural investigation indicated that boron addition led to the formation of hard borides and grain refinement. Different boride morphologies that varied with the cooling rates were identified. The compression strength at room temperature improved by a factor of 3.5 with boron addition without considerably decreasing the ductility.     

Depuration of Oysters (Crassostrea gigas) Contaminated with Vibrio parahaemolyticus and Vibrio vulnificus with UV Light and Chlorinated Seawater

The efficacy of depuration using UV light and chlorinated seawater for decontaminating Vibrio parahaemolyticus and Vibrio vulnificus from oysters was investigated. Oysters were contaminated with a five-strain cocktail of V. parahaemolyticus or V. vulnificus to levels of 10(4) to 10(5) CFU ml(-1) for bioaccumulation. The depuration was conducted in a closed system in which 350 liters of seawater was recirculated at a rate of 7 liters/min for 48 h at room temperature. Counts of V. parahaemolyticus or V. vulnificus were determined at 0, 6, 18, 24, and 48 h. Three treatments were conducted: T1, control treatment; T2, UV treatment; and T3, UV plus chlorine treatment. After 48 h of depuration of V. parahaemolyticus, T3 reduced the count by 3.1 log most probable number (MPN) g(-1) and T2 reduced the count by 2.4 log MPN g(-1), while T1 reduced the count by only 2.0 log MPN g(-1). After 48 h of depuration of V. vulnificus, T2 and T3 were efficient, reducing the counts by 2.5 and 2.4 log MPN g(-1), respectively, while T1 reduced the count by only 1.4 log MPN g(-1). The UV light plus chlorine treatment was more efficient for controlling V. parahaemolyticus in oysters. Both UV light and UV light plus chlorine were efficient for V. vulnificus. The present study is the first report showing the efficacy of depuration systems for decontaminating V. parahaemolyticus and V. vulnificus in oysters cultivated on the Brazilian coast. This study provides information on processes that can contribute to controlling and preventing such microorganisms in oysters and could be used for effective postharvest treatment by restaurants and small producers of oysters on the coast of Brazil.     

Detection of Indentation Induced FE-to-AFE Phase Transformation in Lead Zirconate Titanate

Instrumented indentation was combined with microscopy and spectroscopy analysis to investigate the local mechanically induced ferroelectric to anti-ferroelectric phase transformation of niobium-modified lead zirconate titanate 95/5. Indentation experiments to a depth of 2 μm were performed using a Berkovich pyramidal three-sided diamond tip. Subsequent Raman spectroscopy and piezoelectric force microscopy revealed that indentation locally induced the ferroelectric to antiferroelectric phase transformation. Piezoelectric force microscopy demonstrated the ability to map the individual phases within and near indented regions on the niobium-modified lead zirconate titanate ceramics.     

Characterization of clays used in the ceramic manufacturing industry by reflectance spectroscopy: An experiment in the São Simão ball-clay deposit, Brazil

The characterization of clays from the physical, chemical, and ceramic standpoint in pre-and-within mining stages is a necessary step. However, succinct mining planning, lack of industry-oriented standards and the usual bond to empirical discrimination of clays as regards their use, imply in mixing chemically and technologically different materials, with serious consequences to the mining and manufacturing process. Taking the alluvium-derived, ball-clay deposit of São Simão (SS) as a case study, this works aims to evaluate the potential of reflectance spectroscopy (RS) as a method to define types, purity and crystallinity of clays and to seek a possible relation between spectral characteristics of clays and their use in the ceramic industry. The SS deposit hosts three types of clays that were spectrally set apart based on RS. The technique indicated that the white clays comprise highly ordered kaolinite, mica, smectite and lepidocrosite (first finding in Brazilian alluviums). The brown clays are also rich in well-ordered kaolinite and contain abundant Fe-bearing minerals, as goethite, hematite and siderite (rarely found in alluviums). The gray clays are kaolinite-poor and are abundant in organic matter and smectites. Each of the clay classes typified in the SS deposit has a specific application in the fine ceramic industry, indicating the prominent potential of RS to characterize industrial materials.     

Kinetic analysis of spermine binding to NRD convertase

N-arginine dibasic convertase cleaves polypeptides between paired basic residues containing the sequence Arg-Arg or Arg-Lys. The enzyme contains a large anionic domain, which in the rat enzyme consists of 57 acidic residues out of a stretch of 76 amino acids. Polyamines modulate the activity of the enzyme presumably by binding at the anionic domain (Csuhai et al. (1995) Biochemistry 34, 12411-12419). In this study a kinetic analysis of the effect of salts and amines, particularly the polyamine spermine, on the rat enzyme was studied. Simple salts were inhibitory with no apparent specificity for the anion or cation. Inhibition resulted in an increased Km and a decreased Vmax. Evidence that amines bind to an anionic domain was obtained by the finding that N,N-bis [2-hydroxyethyl]-2-aminoethanesulfonic acid, which is structurally related to the inhibitory amine triethanolamine, is noninhibitory. Inhibition exhibited a complex dependence on spermine concentration. The data fit a model in which enzyme-spermine and enzyme-(spermine)2 complexes are formed. A pH-independent Kd ( approximately 0.1 microM) was obtained for enzyme-spermine formation, while enzyme-(spermine)2 formation was dependent on pH; Kd at pH 6.5 = 1 microM and a Kd at pH 8 = approximately 16 microM. Direct binding of spermine was demonstrated by the ability of spermine to increase the thermal stability of the enzyme. The concentration dependence for the spermine-induced increase in thermal stability fits a model in which formation of the enzyme-spermine complex is sufficient to account for the observed changes.     

Breakdown and latent damage of ultra-thin gate oxides under ESD stress conditions

Time-dependent dielectric breakdown of 2.2–4.7 nm gate oxides is investigated down to the nanosecond time regime. The so-called 1/E model best fits the time-to-breakdown data. Latent damage is also examined and it is seen that the trap generation rate, i.e., the damage rate, is pulse-width dependent, and, thus, d.c. data should not be used to predict the degradation rate under ESD-type stress conditions. Voltage overshoots and a slow turn-on time make low voltage triggered silicon controlled rectifiers bad candidates for protecting the ultra-thin gate oxide against CDM stress.