Rotor resonances of high-speed permanent-magnet brushless machines

For high-speed machines, in particular, it is very important to accurately predict natural frequencies of the rotor at the design stage so as to minimize the likelihood of failure. Finite-element analysis and experimental measurements are used to establish the natural frequencies and modes of the rotor of a high-speed permanent-magnet brushless motor, and to assess the influence of leading design parameters, such as the active length, the shaft diameter and extension, the bearings, and the material properties.     

Low linolenate and commercial soybean oils diminish serum HDL cholesterol in young free-living adult females

OBJECTIVE: A mutant soybean line (A16) low in linolenic acid content (2% of oil by weight) was developed to increase oil oxidative stability. It was unknown whether serum lipid and lipoprotein concentrations in humans would be affected should A16 soybean oil (A16 oil) replace commercial soybean oil in diets. This study was conducted to examine the hypothesis that in free-living normolipidemic women, the consumption of A16 oil at approximately 10% of energy intake (en%) would not affect serum lipids and lipoproteins differently than would the consumption of the same amount of a commercial soybean oil with 7% of linolenic acid content. DESIGN: Fifteen free-living female college students consumed the soybean oil daily with regular meals for 9 weeks in different orders, with each test oil being eaten for 3 weeks. During the study, 13 en% was provided by each test oil and a total of 35 en% was from dietary fat. Serum concentrations of total cholesterol, high-density lipoprotein cholesterol (HDL cholesterol), low-density lipoprotein cholesterol (LDL cholesterol) and triacylglycerides (TAG) were measured. Serum total fatty acid patterns were analyzed as well. RESULTS: Each of the three test oils decreased serum total cholesterol, LDL cholesterol and TAG concentrations from the baseline values. The feeding of A16 and commercial soybean oils decreased serum HDL cholesterol significantly compared with coconut oil (p < 0.05). Dietary inclusion of coconut oil increased serum myristic acid significantly more than did either soybean oil (p < 0.01). Serum arachidonic acid concentrations were significantly greater with A16 consumption than with commercial soybean oil consumption (p < 0.001). CONCLUSION: A16 and commercial soybean oils both diminished serum HDL cholesterol. Although the fatty acid composition differed between the two soybean oils, A16 oil and commercial oil had similar effects on serum concentrations of lipoproteins and lipids. With increased oxidative stability, A16 oil is a good alternative to commercial soybean oil.     

Fouling of microfiltration and ultrafiltration membranes by natural waters

Membrane filtration (microfiltration and ultrafiltration) has become an accepted process for drinking water treatment, but membrane fouling remains a significant problem. The objective of this study was to systematically investigate the mechanisms and components in natural waters that contribute to fouling. Natural waters from five sources were filtered in a benchtop filtration system. A sequential filtration process was used in most experiments. The first filtration steps removed specific components from the water, and the latter filtration steps investigated membrane fouling by the remaining components. Particulate matter (larger than 0.45 microm) was relatively unimportant in fouling as compared to dissolved matter. Very small colloids, ranging from about 3-20 nm in diameter, appeared to be important membrane foulants based on this experimental protocol. The colloidal foulants included both inorganic and organic matter, but the greatest fraction of material was organic. When the colloidal fraction of material was removed, the remaining dissolved organic matter (DOM), which was smaller than about 3 nm and included about 85-90% of the total DOM, caused very little fouling. Thus, although other studies have identified DOM as a major foulant during filtration of natural waters, this work shows that a small fraction of DOM may be responsible for fouling. Adsorption was demonstrated to be an important mechanism for fouling by colloids.     

Localization and speciation of chromium in subterranean clover using XRF, XANES, and EPR spectroscopy

Optimization of phytoremediation and assessment of potential health hazards from metals in the environment requires an understanding of absorption, localization, and transport of the target metal by plants. The objectives of this study were to localize Cr and determine the oxidation state and possible complexation mode of Cr in intact plant tissue by means of XANES, synchrotron XRF microprobe spectroscopy, and EPR spectroscopy. Subterranean clover (Trifolium brachycalycinum) was grown hydroponically with Cr(VI) (0.04-2.0 mmol L(-1)) and compared with plants grown without Cr and with inorganic Cr(III) and various Cr(III)-organic sources. The uptake, translocation, and form of Cr in the plant were dependent on the form and concentration of supplied Cr. Chromium was found predominately in the +3 oxidation state, regardless of the Cr source supplied to the plant, though at high Cr(VI) treatment concentrations, Cr(VI) and Cr(V) were also observed. At low Cr(VI) concentrations, the plant effectively reduced the toxic Cr(VI) to less toxic Cr(III), which was observed both as a Cr(III) hydroxide phase at the roots and as a Cr(III)-organic complex in the roots and shoots. At low Cr(VI) treatment concentrations, Cr in the leaves was observed predominately around the leaf margins, while at higher concentrations Cr was accumulated at leaf veins.     

SPARC deficiency leads to early-onset cataractogenesis

PURPOSE: To determine the role of SPARC (secreted protein, acidic, and rich in cysteine) in cataractogenesis by examining mice deficient in a matricellular protein SPARC. METHODS: Mice were rendered SPARC-deficient by a targeted disruption of the gene. Slit-lamp microscopy and histology were used to examine the eyes of SPARC-null and wild-type mice from birth to 14 months of age. RESULTS: SPARC-null mice developed opacities in the posterior cortex of the eye as early as 1.5 months after birth. The diffuse cataracts appeared to progress toward the anterior cortex and reached maturity in many animals by 3.5 months of age. Early stages of cataractogenesis in SPARC-null mice included inhibition of normal lens fiber cell differentiation, degeneration of fiber cells, vacuole formation at the equator, and liquefaction of the cortex. No cataracts were detected in wild-type mice up to the age of 8 months. CONCLUSIONS: The early onset of cataracts in SPARC-null mice establishes that the gene is essential to the maintenance of lens transparency.     

Synthesis of the four isomers of 4-aminopyrrolidine-2,4-dicarboxylate: identification of a potent, highly selective, and systemically-active agonist for metabotropic glutamate receptors negatively coupled to adenylate cyclase

The four isomers of 4-aminopyrrolidine-2,4-dicarboxylate (APDC) were prepared and evaluated for their effects at glutamate receptors in vitro. (2R,4R)-APDC (2a), an aza analog of the nonselective mGluR agonist (1S,3R)-1-aminocyclopentane-1,3-dicarboxylate (1S,3R)-ACPD, 1), was found to possess relatively high affinity for metabotropic glutamate receptors (mGluRs) (ACPD-sensitive [3H]glutamate binding IC50 = 6.49 +/- 1.21 microM) with no effects on radioligand binding to NMDA, AMPA, or kainate receptors up to 100 microM. None of the other APDC isomers showed significant mGluR binding affinity, indicating that this interaction is highly stereospecific. Both 1 and 2a were effective in decreasing forskolin-stimulated cAMP formation in the adult rat cerebral cortex (EC50 = 8.17 +/- 2.21 microM for 1; EC50 = 14.51 +/- 5.54 microM for 2a); however, while 1 was also effective in stimulating basal tritiated inositol monophosphate production in the neonatal rat cerebral cortex (EC50 = 27.7 +/- 5.2 microM), 2a (up to 100 microM) was ineffective in stimulating phosphoinositide hydrolysis in this tissue preparation, further supporting our previous observations that 2a is a highly selective agonist for mGluRs negatively coupled to adenylate cyclase. Microelectrophoretic application of either 1 or 2a to intact rat spinal neurons produced an augmentation of AMPA-induced excitation (95 +/- 10% increase for 1, 52 +/- 6% increase for 2a). Intracerebral injection of 1 (400 nmol) produced characteristic limbic seizures in mice which are not mimicked by 2a (200-1600 nmol, ic). However, the limbic seizures induced by 1 were blocked by systemically administered 2a in a dose-dependent manner (EC50 = 271 mg/kg, ip). It is concluded that (2R,4R)-APDC (2a) is a highly selective, systemically-active agonist of mGluRs negatively coupled to adenylate cyclase and that selective activation of these receptors in vivo can result in anticonvulsant effects.     

The apolipoprotein E allele epsilon 4 is overrepresented in patients with the Lewy body variant of Alzheimer's disease

We determined apolipoprotein E (ApoE) genotypes in 122 autopsied demented patients. The frequency of the ApoE epsilon 4 allele was 39.6% in Alzheimer's disease (AD), 29.0% in the Lewy body variant of AD (LBV), and 6.25% in diffuse Lewy body disease. For AD and LBV patients, the epsilon 4 frequency was significantly higher than that reported in nondemented controls (10 to 15%). Therefore, LBV and AD share ApoE epsilon 4 as a genetic risk factor, providing further evidence that these conditions overlap.     

Coronary artery fistula after cardiac transplantation

A cardiac transplant recipient with multiple coronary artery fistulae draining into the right ventricle is described. These fistulae presumably resulted from repeated endomyocardial biopsies. The diagnosis of coronary artery fistulae was made at the annual coronary arteriography. The magnitude of the shunt remained small over eight years of follow-up.