KINETICS AND MECHANISM OF QUERCETIN OXIDATION

The kinetics of quercetin oxidation in air were determined spectrophotometrically in the pH region 4 to 7 in 50% alcohol solution at 50° C. The rate at constant pH, found to be first order with respect to quercetin, exhibited pH dependence, with the rate rising with decreasing hydrogen ion concentration. Decrease in oxygen concentration was found to decelerate the reaction. Experiments using diphenyl picrylhydrazyl indicated the presence of free radicals. The mechanism of quercetin oxidation could be fitted into the model consistent with initial ionization of quercetin to its anion and its subsequent reaction with oxygen in a fast step, followed by a unimolecular decomposition to the oxidized quercetin and hydroxyl ion via a one electron transfer mechanism. The primary step in the formation of chill haze in beer appears to be the oxidation of the phenolic entity.     

The real problem in the study of culture.

Comments on the discussion of the difficulties that have impeded the mainstreaming of culture, ethnicity, and race in American psychology by H. Betancourt and S. R. López (see record 1993-41028-001). Solutions of increased specificity or reliance on practitioners of mainstream psychology to modify patterns are rejected as incomplete because neither solution promises more attention to ethnicity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of incest on self and social functioning: A developmental psychopathology perspective.

The effects of child sexual abuse have become a leading concern of mental health service providers. Despite an explosion of studies, one major difficulty in this research is the lack of a developmentally sensitive model for conceptualizing short- and long-term effects and continuity and discontinuity of effects over time. This article proposes a model based in the perspective of developmental psychopathology. It is argued that incest has its unique negative effects in the domains of self- and social functioning, specifically in jeopardizing self-definition and integration, self-regulatory processes, and a sense of security and trust in relationships. Studies with clinical samples indicate that diagnostic conditions associated uniquely with a history of incest reflect serious self- and social impairments. A review of the developmental literature on self- and social development summarizes each major developmental transition from infancy to middle adulthood, and the implications for the negative effects of incest on development are discussed. Finally, implications for developmentally sensitive research are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Environmental toxins and behavioral development: A new role for psychological research.

Presents a new multiple-effects model that emphasizes subtle behavioral alteration as an early sign of toxicity and as evidence that a particular chemical agent may produce long-term impairment in susceptible individuals. The permeability of the placenta to a variety of chemical agents and the special sensitivity of the fetus to some of these agents draws attention to prenatal exposure and the need for prospective longitudinal studies of affective, social, and cognitive development in exposed individuals. The multiple-effects model provides a role for the psychologist in teratological diagnosis and research since the measurement of behavioral variation has developed primarily in psychology. Limitations inherent in both experimental animal research and correlational human studies of toxic effects make it necessary for these methodologies to be used in a complementary fashion. The implications of behavioral teratology for the study of human development and the design of protective social policies are discussed. (45 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cholesterol and Antioxidant Vitamins in Fat Fraction of Whole and Skimmed Dairy Products

The skimming procedure is a common practice in dairy industry, and skimmed products contain less fat, less cholesterol and less fat-soluble vitamins than whole products. The aim of this research is to verify if something else happens during the skimming process to these compounds in milk and dairy products. Experimental milk and cream samples, ranging from 0.1 to 51.5 g fat/100 g, have been studied for beta carotene, alfa-tocopherol and cholesterol contents. The degree of antioxidant protection (DAP), useful to estimate the potential oxidative stability of fat in foods, has been calculated, combining these values. The same analytical protocol has been also applied to commercial products (fat content ranging from 0.1 to 85.0 g/100 g). As was expected, there is a good linear correlation between these compounds and fat content in experimental and in commercial samples; nevertheless, the composition of milk fat changes differently. During skimming process, in the residual fat matter, cholesterol concentration increases while antioxidant compound concentration decreases or remains unchanged. Moreover, in experimental and in commercial milk and dairy, the DAP values show that the residual cholesterol is more susceptible to oxidation in skimmed than in whole products. This aspect is particularly important from a safety point of view: actually, cholesterol oxide ingestion can be harmful and should be avoided even in a small amount.     

Manganese‐Promoted Regioselective Ring‐Opening of 2,3‐Epoxy Acid Derivatives: A New Route to α‐Hydroxy Acid Derivatives

A simple and general methodology directed towards the synthesis 3‐aryl‐2‐hydroxy amides, or esters with total regioselectivity from the easily available 2,3‐epoxy amides or esters, promoted by active manganese is described. Utilizing enantiopure epoxy amides as starting materials, the corresponding 3‐aryl‐2‐hydroxy amides in enantiopure form are also available. Some synthetic applications of selected examples of 3‐aryl‐2‐hydroxy carboxylic acid derivatives are shown. A mechanism has been proposed to explain this novel reaction.     

Derivation of a Retinoid X Receptor Scaffold from Peroxisome Proliferator‐Activated Receptor γ Ligand 1‐Di(1H‐indol‐3‐yl)methyl‐4‐trifluoromethylbenzene

PPARγ agonist DIM‐Ph‐4‐CF ₃ , a template for RXRα agonist (E)‐3‐[5‐di(1‐methyl‐1H‐indol‐3‐yl)methyl‐2‐thienyl] acrylic acid: DIM‐Ph‐CF₃ is reported to inhibit cancer growth independent of PPARγ and to interact with NR4A1. As both receptors dimerize with RXR, and natural PPARγ ligands activate RXR, DIM‐Ph‐4‐CF₃ was investigated as an RXR ligand. It displaces 9‐cis‐retinoic acid from RXRα but does not activate RXRα. Structure‐based direct design led to an RXRα agonist.

     

Detrended fluctuation analysis of intracranial pressure predicts outcome following traumatic brain injury

Detrended fluctuation analysis (DFA) is a recently developed technique suitable for describing scaling behavior of variability in physiological signals. The purpose of this study is to explore applicability of DFA methods to intracranial pressure (ICP) signals recorded in patients with traumatic brain injury (TBI). In addition to establishing the degree of fit of the power-law scaling model of detrended fluctuations of ICP in TBI patients, we also examined the relationship of DFA coefficients (scaling exponent and intercept) to: 1) measures of initial neurological functioning; 2) measures of functional outcome at six month follow-up; and 3) measures of outcome, controlling for patient characteristics, and initial neurological status. In a sample of 147 moderate-to-severely injured TBI patients, we found that a higher DFA scaling exponent is significantly associated with poorer initial neurological functioning, and that lower DFA intercept and higher DFA scaling exponent jointly predict poorer functional outcome at six month follow-up, even after statistical control for covariates reflecting initial neurological condition. DFA describes properties of ICP signal in TBI patients that are associated with both initial neurological condition and outcome at six months postinjury.      

Effect of chitosan on physical and chemical processes during bread baking and staling

The objective of this research was to investigate the effect of chitosan on the interaction of water with bread ingredients and on the rate of staling. The changes in freezable bound water and total water contents in bread crumb were assessed by differential scanning calorimetry from water melting and evaporation endothermic peak areas. It was found that freezable water content and total water content in bread crumb decrease during staling more rapidly in the presence of chitosan. The weak interaction of freezable water with protein and starch polymeric chains in bread crumb becomes stronger, but the interaction of nonfreezable bound water with protein and starch molecules in bread crumb becomes weaker in the course of staling during bread storage. Two stages of bread crumb staling were indicated. Chitosan increases the rate of bread staling during both stages. It was suggested that during bread staling chitosan increases water migration rate from crumb to crust, prevents amylose-lipid complexation, and increases dehydration rate both for starch and gluten.