Reactions of peroxides: II. Reaction of carboxylic acids with iodine and peroxides

Aroyl peroxides andt-butylperoxy isopropyl carbonate decarboxylate aliphatic carboxylic acids in the presence of iodine to form iodides in high yields. The aroyl peroxides also abstract carboxylic acid hydrogen from aromatic and perfluorocarbon acids. A proposed scheme is presented for the reaction of aroyl peroxides with carboxylic acids illustrating homolytic decarboxylation as taking place in an equilibrium between a pair of acyloxy radicals. These radicals are derived from the peroxide and acid and maintained in association by hydrogen bonding and iodine complexation. Presented at the AOCS Meeting, Washington, D.C., March 1968. ARS, USDA.     

Role of visual imprinting in the emergence of specific filial attachments in ducklings.

Conducted 2 experiments with a total of 36 1-11 day old Khaki Campbell ducklings, to assess the suppression of distress vocalization by 2 distinctive stimuli before and after Ss were imprinted to 1 of the stimuli. In Exp. I, both stimuli strongly suppressed distress calls initially. At 5 days of age, however, only the stimulus involved in imprinting suppressed the calls. Results suggest that the loss of control by the nonimprinted stimulus was age-related and represented the development of fear to insufficiently-familiar stimuli. In Exp. II, 5-11 day old Ss were permitted lengthy exposure to a novel imprinting-type stimulus. Under these circumstances, distress vocalization eventually came under stimulus control. The overall pattern of results suggests that through imprinting, stimuli that innately evoke filial behavior become familiar and thus are prevented from later evoking novelty-induced fear. (16 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relation of formal thought disorder to the communication deficit in schizophrenics.

Evaluated 40 schizophrenics and 20 normals on a social communication task and on an individual cognitive task, both designed to reveal decentering deficits. It was hypothesized that the processes underlying the schizophrenic's thought disorder are formally similar to the processes involved in his deviant organization of social situations, specifically social communication, with both deficits to be interpreted in terms of faulty decentering. Schizophrenics manifested a decentering deficit on both the social communication (p     

Determination of Optimum Burn-In Time: A Composite Criterion

The object of this paper is to present a mathematical model capable of determining the optimum amount of time that semiconductor devices, which have specified life characteristics, must be placed on burn-in to obtain maximum performance versus total cost. To make the model operational and realistic, the traditional assumption of an exponential (more recently, Weibull) distribution of life is omitted in favor of the generalized gamma distribution (GGD). This is done because the GGD includes, as special cases, such distributions as the normal, Rayleigh, Maxwell, chi, chi2, Weibull, exponential, ordinary gamma, etc. The use of the greater representational capability of the GGD is justified in the results of the studies showing that (other things being equal) small changes in parametric values of life characteristics can cause vast differences in the optimum burn-in time and maximum system effectiveness. The physical performance sector of the model incorporates system effectiveness that includes such factors as availability, expected time to repair, mission reliability, system use coefficient, storage survival probability, and operational readiness. The costs considered are those due to burn-in operation, production, and sales. The model has been studied by use of computer runs from the standpoint of critical analysis and parametric sensitivity analysis.     

Initial experience of clinical pharmacology and clinical pharmacy interactions in a clinical pharmacokinetics consultation service

International statistics indicate that there is a close correlation between the consumption of saturated fats (dairy fats and meat fats) and the mortality from coronary heart disease (CHD), and this conception has been confirmed by many epidemiological studies. Such studies alone, however, cannot prove the existence of a cause-and-effect relationship between these two variables; dietary intervention trials are needed. The Finnish Mental Hospital Study was such a trial, conducted in two hospitals near Helsinki in 1959--1971. Practically total replacement of dairy fats by vegetable oils in the diets of these hospitals was followed by a substantial reduction in the mortality of men from CHD. Total mortality also appeared to be reduced. As to the causes of death other than CHD, none was significantly influenced by dietary change. This was also true for malignant neoplasms. To alleviate the burden of CHD on public health, many investigators have recommended important changes in the quantity and quality of dietary fats.     

Engineered polymeric nanoparticles for soil remediation

Hydrophobic organic groundwater contaminants, such as polynuclear aromatic hydrocarbons (PAHs), sorb strongly to soils and are difficult to remove. We report here on the synthesis of amphiphilic polyurethane (APU) nanoparticles for use in remediation of soil contaminated with PAHs. The particles are made of polyurethane acrylate anionomer (UAA) or poly(ethylene glycol)-modified urethane acrylate (PMUA) precursor chains that can be emulsified and cross-linked in water. The resulting particles are of colloidal size (17-97 nm as measured by dynamic light scattering). APU particles have the ability to enhance PAH desorption and transport in a manner comparable to that of surfactant micelles, but unlike the surface-active components of micelles, the individual cross-linked precursor chains in APU particles are not free to sorb to the soil surface. Thus, the APU particles are stable independent of their concentration in the aqueous phase. In this paper we show that APU particles can be engineered to achieve desired properties. Our experimental results show that the APU particles can be designed to have hydrophobic interior regions that confer a high affinity for phenanthrene (PHEN) and hydrophilic surfaces that promote particle mobility in soil. The affinity of APU particles for contaminants such as PHEN can be controlled by changing the size of the hydrophobic segment used in the chain synthesis. The mobility of colloidal APU suspensions in soil is controlled by the charge density or the size of the pendent water-soluble chains that reside on the particle surface. Exemplary results are provided illustrating the influence of alternative APU particle formulations with respect to their efficacy for contaminant removal. The ability to control particle properties offers the potential to produce different nanoparticles optimized for varying contaminant types and soil conditions.