Effects of Ketone Bodies on Brain Metabolism and Function in Neurodegenerative Diseases

Under normal physiological conditions the brain primarily utilizes glucose for ATP generation. However, in situations where glucose is sparse, e.g., during prolonged fasting, ketone bodies become an important energy source for the brain. The brain’s utilization of ketones seems to depend mainly on the concentration in the blood, thus many dietary approaches such as ketogenic diets, ingestion of ketogenic medium-chain fatty acids or exogenous ketones, facilitate significant changes in the brain’s metabolism. Therefore, these approaches may ameliorate the energy crisis in neurodegenerative diseases, which are characterized by a deterioration of the brain’s glucose metabolism, providing a therapeutic advantage in these diseases. Most clinical studies examining the neuroprotective role of ketone bodies have been conducted in patients with Alzheimer’s disease, where brain imaging studies support the notion of enhancing brain energy metabolism with ketones. Likewise, a few studies show modest functional improvements in patients with Parkinson’s disease and cognitive benefits in patients with—or at risk of—Alzheimer’s disease after ketogenic interventions. Here, we summarize current knowledge on how ketogenic interventions support brain metabolism and discuss the therapeutic role of ketones in neurodegenerative disease, emphasizing clinical data.     

The impacts of a GTL plant on Brazil's oil products supply and refinery expansion

This paper assesses the impacts of a GTL plant on the expansion of Brazil's oil refining segment. The GTL plant (50,000 bpd) was sized to start up operations in 2015, producing diesel and naphtha through the indirect route (FT-synthesis). This plant will consume the non-associated natural gas production from the recent discoveries at the Santos Basin (around 419 Bm³), and the associated gas production from the Campos Basin. Both basins are located in the Southeast of Brazil, the most populated, rich and industrialized region of the country. Two different criteria for refinery expansion were simulated in order to meet oil product demand scenarios. Findings show that depending on the refinery expansion criteria considered GTL will play a fundamental hole to meet the oil product demand forecast to Brazil in the next 10 years.     

Dynamic cost shifting in hospitals: evidence from the 1980s and 1990s

The purpose of this paper is to determine whether dynamic cost shifting occurred among acute care hospitals during the period from the early 1980s to the early 1990s and, if so, whether market factors affected the ability to shift costs. Evidence from this study of California acute care hospitals during three time intervals shows that the hospital did practice dynamic cost shifting, but that their ability to shift costs decreased over time. Surprisingly, hospital competition and HMO penetration did not influence cost shifting. However, increasing HMO penetration (measured as the HMO percentage of hospital discharges) did decrease both net prices and costs for the early part of the study, but later was associated with increases in both.     

Pulsed-current duty cycle dependence of electromigration-inducedstress generation in aluminum conductors

The effect of duty cycle of pulsed dc currents on the critical length-current density product, (jl_c), was measured using the Blech-Kinsbron edge-displacement technique [Thin Solid Films 25, 327 (1975)]. Unencapsulated Al edge-displacement segments mere stressed at various duty cycles and the critical lengths, the so-called “Blech lengths”, were measured. It was found that jl_c increased with decreasing duty cycle. We measured a factor of 2.6 increase in jl_c for the 25% duty cycle as compared to dc. This duty cycle dependence of Blech length implies that electromigration resistance for an integrated circuit would be increased for small duty cycle operation by increasing the fraction of interconnects which are sub-Blech-length and are not susceptible to EM damage     

Simulation and computer-aided kinematic design of three-degree-of-freedom spherical parallel manipulators

Parallel robotic manipulators are complex mechanical systems that lead to involved kinematic and dynamic equations. Hence, the design of such systems is in general not intuitive, and advanced simulation and design tools specialized for this type of architecture are highly desirable. This article discusses the kinematic simulation and computer-aided design of three-degree-of-freedom spherical parallel manipulators with either prismatic or revolute actuators. The kinematic analysis of spherical parallel manipulators is first reviewed. Solutions for the direct and inverse kinematic problems are given, and the expressions for the singularity loci are then introduced. The determination of the workspace of this type of manipulator is also addressed. Finally, a computer package developed specifically for the CAD of spherical parallel manipulators is presented. This package allows the interactive analysis of manipulators of arbitrary architecture including the representation of the workspace, the representation of singularities, and the graphic animation of trajectories specified either by the direct or the inverse kinematic module. It can be used for the design of any spherical parallel three-degree-of-freedom actuated mechanism, which can find many applications in high-performance robotic systems. © 3995 John Wiley & Sons, Inc.     

Impact of parental discipline methods on the child's internalization of values: A reconceptualization of current points of view.

It is generally argued that parental use of specific discipline techniques (e.g., reasoning vs power assertion) differentially affects a child's internalization. This article offers an expanded formulation. Internalization as a result of discipline is proposed to be based on a child's accurate perception of the parental message and acceptance or rejection of it. Mechanisms promoting acceptance are perceptions of the parent's actions as appropriate, motivation to accept the parental position, and perception that a value has been self-generated. Features of the misdeed, discipline technique, child, and parent that affect accurate perception and acceptance–rejection are outlined. Other goals besides internalization, such as movement beyond the parent's position, maintenance of the child's self-esteem, and maintenance of the parent–child relationship, are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Analytic and numerical calculations of the formation of a sulphuric acid aerosol in the upper troposphere

Analytic and numerical calculations are performed on the production of sulphuric acid aerosol in conditions of a very large nucleation event observed in the upper troposphere. The numerical results feature a growing peak in the size distribution whose magnitude is reproduced well analytically, and are consistent with the observed particle number concentration at sizes greater than 25 nm (measured dry diameter), but suggest that most of the aerosol was at unobserved smaller sizes. Because of growth and coagulation, number concentrations of the aerosol rapidly become independent of the number initially nucleated, so that conclusions as to the nucleation process, either homogeneous or ion-induced nucleation, cannot easily be drawn from existing atmospheric observations. The final concentration is very insensitive to the magnitude of the SO₂ source, but, if condensation on, and coagulation with, a remnant background aerosol occurs, such nucleation events will be cut off for source magnitudes less than a specific value. Anthropogenic emissions of SO₂ which exceed this value can produce higher aerosol number concentrations in the atmosphere with consequences for the indirect effect of aerosols on the climate.     

Economic Comparison of NdFeB and Hard Ferrites in Automotive Applications

With the increasing use of electric motors in automobiles—in some cases as many as 100 electric motors per vehicle—alternatives to ferrite magnetic materials are under consideration. If more powerful magnetic materials could be implemented, size reductions in these motors could result in curb weight reductions that lead to improved fuel economy. NdFeB magnets are attractive as potential replacement materials, due to their higher flux density and thus smaller required size; however, high material costs have limited their implementation. To investigate the economic competitiveness of alternative magnetic materials, technical cost models (TCMs) were developed and used to examine the manufacturing economics related to the production of both NdFeB and ferrite magnets. Results from the TCMs are used to identify the cost drivers and opportunities for cost reductions. Subsequent investigations will include effects on vehicle fuel efficiency, and the environmental impact of magnet manufacture and disposal.     

A profile of science in Brazil

The Brazilian contribution to publications in science and humanities increased from 0.29% of the worldwide total in 1981 to 0.46% in 1993. In science, but not in humanities, Brazilian publications tend to follow the world publication trend; thus, during the period 1981–1993, 57.9% of Brazilian publications were in life sciences, 35.4% in exact sciences, 3.9% in earth sciences and 2.9% in humanities. The ten institutions with the largest number of publications are universities, which account for half of the all Brazilian publications. The total number of authors on the Brazilian 1981–1993 publications was 52,808. Among these 57.8% appear in only one publication and 17.5% have their publications cited more than 10 times.     

Project Preserve: A Program to Retain Minorities in Engineering

A national effort, begun in 1972 to increase the numbers of minorities in engineering, has made substantial progress, but the attrition for minority students is still estimated at 70%. To address the problem, Project Preserve was designed to confirm, by demonstration, the results of previous research showing that the combination of explicit cognitive development, close relationships with faculty, and strong bonds to an institution can raise the performance and retention of minority engineering students. The project enrolled over 100 minority engineering students who had been dismissed from freshman engineering studies on other campuses or placed on academic probation, but whose high school grades and SAT scores were indicative of success. They were channeled into participating institutions chosen for their record of basic support services, willingness to augment or restructure those services, and for variation among institutional variables: Xavier University of Louisiana (XU), California State University at Northridge (CSUN), and City College of the City University of New York (CCNY). A 2 1/2 hour battery of evaluation instruments was given to 79 students upon entry and to 26 students upon their attaining Junior status after two years in the program. The results demonstrated that: (1) an admirable 64% of would-be drop outs had achieved Junior status or were still enrolled in engineering at the conclusion of two years; (2) cognitive growth occurred on basic memory skills and one critical thinking skill, but there were institutional differences in the extent of intellectual development, with Xavier producing the most change; (3) closer relationships to faculty were outcomes; (4) the most positive feelings about, or bonding to, the institution occurred at Xavier University, while the most evidence of social participation and connectedness occurred at CSUN.