PET validation of a novel prefrontal task: Delayed response alteration.

Deficits in working memory have been proposed to explain the performance failures of frontally lesioned primates on delayed alternation (DA) and delayed response (DR) tasks. The authors examined a computerized test of delayed response alternation (DRA), which combines elements of DR and DA in a sample of 18 normal volunteers who underwent oxygen-15 PET regional cerebral blood flow scans during the DRA and a sensorimotor control task. Significant activations were observed in a network of frontal, parietal, occipital, and temporal regions during initial task performance. A qualitatively similar but somewhat reduced set of activations was observed in a subset of participants who repeated the task after practice and instruction. These results are consistent with distributed models of working memory derived from studies of nonhuman primates and suggest that the frontal lobes contribute to human working memory function. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A wafer-bonded floating-element shear stress microsensor withoptical position sensing by photodiodes

This paper discusses a noninvasive sensing technique for the direct measurement of low-magnitude shear stresses in laminar and turbulent air flows. The sensing scheme detects the flow-induced in-plane displacement of a microfabricated floating-element structure (500 μm×500 μm×7 μm), using integrated photodiodes. The wall-mounted floating-element sensors were fabricated using a wafer-bonding technology. The sensors were calibrated in a custom-designed laminar flow cell and subsequently shown to be able to transduce shear stresses of 0.01 Pa during tests in a low-speed wind tunnel     

Energy requirements of middle-aged men are modifiable by physical activity

BACKGROUND: Energy requirements for weight maintenance decrease with age. Often, this decline is not proportionately matched by reduced energy intake, resulting in weight gain. OBJECTIVE: We hypothesized that energy requirements for total daily weight maintenance in healthy, sedentary, middle-aged men would increase after regular aerobic exercise or aerobic exercise plus weight loss to levels comparable with those in middle-aged athletes. DESIGN: Weight-maintenance energy requirements were determined during weight stability (+/- 0.25 kg) in 14 lean, sedentary (LS) men; 18 obese, sedentary (OS) men; and 10 male athletes of comparable ages (x +/- SEM: 58 +/- 1 y). Studies were done at baseline and after 6 mo of aerobic exercise (LS men) or aerobic exercise plus weight loss (OS men) or 3 mo of deconditioning (athletes). RESULTS: The interventions raised maximal oxygen uptake (VO2max) by 15% in the LS men and by 13% in the OS men and decreased it by 14% in athletes (all P < 0.01), eliminating the differences among groups at baseline. Body fat was reduced significantly in LS and OS men; fat-free mass decreased in OS men. Average daily energy requirements increased by 8% in LS men and by 5% in OS men (both P < 0.01) to levels comparable with the baseline requirements of athletes and correlated with VO2max (r2 = 0.22, P < 0.0001) and fat-free mass (r2 = 0.05, P < 0.02) across the range of VO2max achieved by all subjects. CONCLUSIONS: Under free-living conditions, aerobic exercise eliminated the difference in weight-maintenance energy requirements between middle-aged sedentary and athletic men, suggesting that energy requirements of healthy, middle-aged men are modifiable by regular physical activity.     

Identification of potent inhibitors of Plasmodium falciparum plasmepsin II from an encoded statine combinatorial library

An encoded 13,020-member combinatorial library was synthesized containing a statine core. Evaluation of this library with plasmepsin II, an aspartyl protease required for hemoglobin metabolism in the malaria parasite, led to the identification of potent and selective inhibitors as well as novel structure-activity relationships.     

Radiographic evaluation of complications after jejunoileal bypass surgery

A retrospective analysis of 89 patients who underwent jejunoileal bypass surgery for morbid obesity disclosed 33 complications that were detected radiographically. Intestinal obstruction (10.1% of patients), cholecystitis (5.6%), renal stones (4.5%), peptic ulcer (3.4%), megacolon (6.7%), and elongation of the small intestine with hypertrophy of the mucosal folds of the jejunum (6.7%) were diagnosed solely by radiographic means.     

Simple automatic initiator for microwave induced plasmas

A simple circuit is described which is used to maintain continuity of a radio-frequency or microwave induced plasma. The microwave power reflected from the discharge is monitored. Upon an increase of the reflected power which indicates that the plasma has become extinguished, a high-voltage pulse is applied to a coil wrapped around the discharge region. The repetition rate, voltage of the pulse, and threshold of reflected power are adjustible. This circuit is applicable to resonance fluorescence, atomic absorption and emission, and kinetic determinations.     

Environmental decision-making: Social indicators,simulation, and public choice

A number of parallels exist between the development of social indicators and of simulation models. This paper seeks to clarify the nature of these parallels and to place them in their respective places vis-a-vis decisions dealing with complex and changing environmental problems. After delineating the role of social indicators and simulation in environmental decision-making, the paper closes with a number of areas where caution and concern are especially important. The principal conclusion is that decision-making for complex environmental problems must be synthetic in nature, and must ultimately rely on well functioning democratic political processes, since political decisions are inherently synthetic. We must avoid simple decisions dictated by technical expediency (unless of course the body politic prefers such decision models and is made aware of alternative technical opinions). In an arena of open political debate and sound technical discussion, the paper concludes that environmental decisions can be taken that respect both the ecosystem and its human inhabitants.     

Ultrasound findings in hepatitis

A retrospective study of ultrasound images of the liver in patients with hepatitis was undertaken. Two distinct ultrasound patterns were detected. In acute hepatitis, the predominant findings were accentuated brightness and more extensive demonstration of the portal vein radicle walls and overall decreased echogenicity of the liver. Chronic hepatitis primarily revealed decreased brightness and number of portal vein radicle walls and verall increased liver echogenicity. In addition, the pathological severity closely paralleled these ultrasound patterns. A prospective study confirmed the same acute hepatitis ultrasound findings with close correlation to the clinical severity. These distinct ultrasound patterns will help to evaluate patients with suspected acute and chronic hepatitis and more accurately define intrahepatic causes of jaundice.