Search Results - (Author, Cooperation:S. C. Cheng)

2014-09-27

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Aerobiosis/immunology ; Animals ; Candida albicans/immunology ; Candidiasis/immunology/metabolism ; Disease Models, Animal ; *Epigenesis, Genetic ; Female ; Glucose/metabolism ; Glycolysis/*immunology ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit/genetics/*metabolism ; Immunity, Innate/*genetics ; Immunologic Memory/*genetics ; Male ; Mice ; Mice, Inbred C57BL ; Monocytes/*immunology/metabolism ; Sepsis/genetics/immunology/metabolism ; Staphylococcal Infections/immunology/metabolism ; Staphylococcus aureus ; TOR Serine-Threonine Kinases/genetics/*metabolism ; Transcriptome ; beta-Glucans/immunology

2014-09-27

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Animals ; Binding Sites/genetics ; Cell Differentiation/*genetics ; Deoxyribonuclease I/chemistry ; *Epigenesis, Genetic ; Genomic Imprinting ; Humans ; Immunity, Innate/*genetics ; Immunologic Memory ; Inflammasomes/genetics/immunology ; Macrophages/*cytology/immunology ; Mice ; Monocytes/*cytology/immunology ; Transcription Factors/metabolism ; beta-Glucans/immunology

1089-7550

AIP Digital Archive

Physics

We have found that stresses induced during magnetron sputter deposition of amorphous TbFe films are very important in determining the thermal stability of the perpendicular anisotropy, Ku. To determine the stress-induced contribution to the anisotropy, the anisotropy was measured with a torque magnetometer before and after peeling films from their substrates. Data clearly show that the fractional change in anisotropy which occurs when the film is peeled from its substrate, ΔKu/Ku, decreases with increasing Ar pressures. Furthermore, annealing studies reveal that the thermal stability of Ku improves with increasing Ar sputtering pressure−a trend which is in conflict with the tendency for films sputtered under low Ar pressure to be more oxidation resistant. This trend is attributed to the large stress-induced anisotropy component which exists at low argon pressures and its tendency to decrease as a result of long-term annealing. Measurements of the anisotropy of films which had been annealed at 200 °C for 815 h showed that the residual Ku after annealing increased with argon pressure. Measurements of the width of the peak in coercivity around Tcomp in these films shows that Hc increases monotonically with argon pressure. This monotonic increase in Hc is attributed to larger local variations in anisotropy caused by the less dense microstructure and the more random local anisotropy produced by the larger angle of incidence of adatoms which results from the increased scattering in the higher pressure sputtering gas.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

The magnetization of rare-earth transition-metal (RE-TM) films has been found to play an important role in single-layer film direct overwrite characteristics. In this study, the magnetization of films was varied by changing the compensation temperature and the Curie temperature, independently. Direct overwrite characteristics which were investigated included the minimum and maximum pulse width to erase and to write a certain size domain, the pulse-width margins for erase, and the erasable size of domain. A decrease in the compensation temperature, which leads to an increase in the magnetization at high temperatures, causes the minimum erasure pulse width to increase and the largest erasable domain size to decrease. However, a decrease in the compensation temperature causes the writing pulse width to decrease. The effects of magnetization on the direct overwrite characteristics were further investigated by applying external magnetic fields up to 580 Oe. The minimum pulse width to erase domains was found to increase with an increase of the applied field, which was in the direction to assist domain nucleation. The maximum erasure pulse width decreases rapidly with an increase of the magnetic field. The disappearance of the erasure margin when the gap between the compensation temperature and the Curie temperature increases results from the fact that the minimum erasure pulse width becomes equal to the minimum writing pulse width. In order to have a wide range of erasable domain sizes, while still maintaining a short writing pulse width, it is shown that film compositions must be adjusted to have both a low compensation temperature and a low Curie temperature.

Electronic Resource

1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Electronic Resource

1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Electronic Resource

1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

—The origin of the acetyl group in acetyl-CoA which is used for the synthesis of ACh in the brain and the relationship of the cholinergic nerve endings to the biochemically defined cerebral compartments of the Krebs cycle intermediates and amino acids were studied by comparing the transfer of radioactivity from intracisternally injected labelled precursors into the acetyl moiety of ACh, glutamate, glutamine, ‘citrate’(= citrate +cis-aconitate + isocitrate), and lipids in the brain of rats. The substrates used for injections were [1-14C]acetate, [2-14C]acetate, [4-14C]acetoacetate, [1-14C]butyrate, [1, 5-14C]citrate, [2-14C]glucose, [5-14C]glutamate, 3-hydroxy[3-14C]butyrate, [2-14C]lactate, [U-14C]leucine, [2-14C]pyruvate and [3H]acetylaspartate.The highest specific radioactivity of the acetyl group of ACh was observed 4 min after the injection of [2-14C]pyruvate. The contribution of pyruvate, lactate and glucose to the biosynthesis of ACh is considerably higher than the contribution of acetoacetate, 3-hydroxybutyrate and acetate; that of citrate and leucine is very low. No incorporation of label from [5-14C]glutamate into ACh was observed. Pyruvate appears to be the most important precursor of the acetyl group of ACh.The incorporation of label from [1, 5-14C]citrate into ACh was very low although citrate did enter the cells, was metabolized rapidly, did not interfere with the metabolism of ACh and the distribution of radioactivity from it in subcellular fractions of the brain was exactly the same as from [2-14C]pyruvate. It appears unlikely that citrate, glutamate or acetate act as transporters of intramitochondrially generated acetyl groups for the biosynthesis of ACh. Carnitine increased the incorporation of label from [1-14C]acetate into brain lipids and lowered its incorporation into ACh.Differences in the degree of labelling which various radioactive precursors produce in brain glutamine as compared to glutamate, previously described after intravenous, intra-arterial, or intraperitoneal administration, were confirmed using direct administration into the cerebrospinal fluid. Specific radioactivities of brain glutamine were higher than those of glutamate after injections of [1-14C]acetate, [2-14C]acetate, [1-14C]butyrate, [1,5-14C]citrate, [3H]acetylaspartate, [U-14C]leucine, and also after [2-14C]pyruvate and [4-14C]acetoacetate. The intracisternal route possibly favours the entry of substrates into the glutamine-synthesizing (‘small’) compartment. Increasing the amount of injected [2-14C]pyruvate lowered the glutamine/glutamate specific radioactivity ratio.The incorporation of 14C from [1-14C]acetate into brain lipids was several times higher than that from other compounds. By the extent of incorporation into brain lipids the substrates formed four groups: acetate 〉 butyrate, acetoacetate, 3-hydroxybutyrate, citrate 〉 pyruvate, lactate, acetylaspartate 〉 glucose, glutamate. The ratios of specific radioactivity of ‘citrate’ over that of ACh and of glutamine over that of ACh were significantly higher after the administration of [1-14C]acetate than after [2-14C]pyruvate.The results indicate that the [1-14C]acetyl-CoA arising from [1-14C]acetate does not enter the same pool as the [1-14C]acetyl-CoA arising from [2-14C]pyruvate, and that the cholinergic nerve endings do not form a part of the acetate-utilizing and glutamine-synthesizing (‘small’) metabolic compartment in the brain. The distribution of radioactivity in subcellular fractions of the brain after the injection of [1-14C]acetate was different from that after [1, 5-14C]citrate. This suggests that [1-14C]acetate and [1, 5-14C]citrate are utilized in different subdivisions of the ‘;small’ compartment.

Electronic Resource

1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Abstract— In the lobster nerve the fixation of CO, at various levels of pCO2 was studied by the incorporation of [l-14C]pyruvate. Incorporation of 14C was solely dependent on CO2 fixation since the C-1 was decarboxylated in the formation of acetyl-CoA. Paired-nerve studies with [2-14C]pyruvate afforded a study of pyruvate metabolism in the lobster nerve. [I14C]Pyruvate was incorporated to nearly the same extent at all levels of pCO2 including zero pCO2, a finding that suggested metabolic recycling of CO2. The magnitude of the metabolic recycling of C-1 of pyruvate or pyruvate dismutation was estimated to be nearly 20 per cent of total CO2 fixation. Re-evaluation of the relative contributions of the CO2 fixation. and acetyl-CoA pathways on the basis of more extensive data gave a ratio of 2:3.The pCO2 affected synthesis of ACh and the level of citrate. With increasing pCO2, the specific radioactivity of ACh decreased much more than the content of ACh. The decrease in the specific radioactivity of ACh but not that of citrate further suggested metabolic compartmentation. The implication of these findings is discussed.Alanine functioned as a metabolic sink for the incorporated pyruvate. Pyruvate levels were estimated to be approximately 0.1 nmol/mg of protein.

Electronic Resource

1749-6632

Blackwell Publishing Journal Backfiles 1879-2005

Natural Sciences in General

Electronic Resource

1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] In the phalaropes (a sub-family of throe species only, two holarctic, one Wilson's (Steganopus tricolor), nearctic) only males incubate and only they form brood patches. Johns and Pfeiffer2 showed experimentally that the hor monal stimuli for brood patch formation in two species of phalaropes (one ...

Electronic Resource

0005-2728

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Chemistry and Pharmacology

Medicine

Physics

Electronic Resource

0003-9861

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Chemistry and Pharmacology

Physics

Electronic Resource

0003-9861

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Chemistry and Pharmacology

Physics

Electronic Resource

0304-4165

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Chemistry and Pharmacology

Medicine

Physics

Electronic Resource

1433-2965

Key words:Bone – Density – Gene – Mineral – Receptor – Vitamin D

Springer Online Journal Archives 1860-2000

Medicine

Abstract: A recent meta-analysis of 16 publications suggested that bone mineral density (BMD) is not associated with vitamin D receptor (VDR) gene polymorphism (VDRGP) at the 0.05 significance level when a study with genotyping mistakes is excluded. We wished to determine whether ‘positive’ findings supporting the BMD–VDRGP association may be explained by chance, and what factors affect the outcomes of these studies. Seventy-five articles and abstracts on the association of VDRGP with BMD and related skeletal phenotypes published before January 1997 were identified. Twenty-three of 67 (34.3%) studies on spinal BMD and 22 of 51 (43.1%) on femoral neck BMD had found a BMD–VDRGP association at p〈0.05, significantly (p= 7 × 10–14 for spinal BMD, p= 9 × 10–16 for hip BMD) higher than the expected 5% false positive rate under the null hypothesis of ‘no association’. ‘Positive’ results were more frequently observed in studies on females before the menopause than those on females after the menopause (p〈0.02) or on male and female subjects combined (p〈0.05) when skeletal phenotypes at any bone sites were considered. The ‘positive rate’ among studies was also influenced by the age range of subjects studied and by the inclusion of subjects with osteoporosis. It is concluded that: (1) BMD is associated with VDRGP with high levels of confidence and (2) non-genetic factors and genetic heterogeneity interfere with the detection of the effects of VDRGP on bone phenotypes.

Electronic Resource

1432-1181

Springer Online Journal Archives 1860-2000

Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Physics

Zusammenfassung Im folgenden Bericht wird ein Rechenprogramm für einfache aber genaue Berechnungen von thermodynamischen und Transporteigenschaften von Frigen R 22 als Funktion von Druck und Temperatur vorgestellt. Das Programm erlaubt ein Voraussagen dieser Eigenschaften sowohl für unterkühlte und gesättigte Flüssigkeiten als auch für gesättigten und überhitzten Dampf. Beim Vergleich verschiedener Versuchsdaten mit den Ergebnissen dieses Codes konnten gute Übereinstimmungen festgestellt werden.

Abstract Simple and accurate prediction methods of the thermodynamic and the transport properties of Freon-22 as a function of pressure and temperature are presented in this paper. The code predicts the thermodynamic and the transport properties for subcooled and saturated liquid and for saturated and superheated vapour. Predictions were compared to various experimental data and showed good agreement.

Electronic Resource

1432-1106

Citric acid ; Micro assay ; Peripheral nerve ; CNS

Springer Online Journal Archives 1860-2000

Medicine

Summary The separation on a Dowex-1-acetate column of glutamic, aspartic, lactic, succinic, and malic acids was described. The “citric acid” (citric, cisaconitic and isocitric acids), fumaric, and oxaloacetic acids were separated. A new method for microdetermination of citric acid was described also. TPNH in the presence of purified aconitase, and isocitric dehydrogenase, is measured fluorometrically. The method permits the determination of 1 mμmole citric acid. The citric acid content of peripheral nerve and brain was measured by this method.

Electronic Resource

1432-1106

CO2 fixation ; citrate ; lobster nerve

Springer Online Journal Archives 1860-2000

Medicine

Summary The specific activity of citric acid of the lobster nerve which was incubated in Ringer-bicarbonate solution containing 14C-bicarbonate was determined. The specific activity of citric acid was higher than that of malic acid by a factor of 2.5. The citric acid obtained from the lobster nerve was degraded with an improved method which is described in this paper. The ratio of the radio-activity of C-6 to C-1 of citric acid was 1∶1. Aspartic acid obtained from the lobster nerve was also degraded, and the ratio of the radioactivity of C4 to C1 was almost 10∶1. From these results, it is assumed that CO2 fixation in the lobster nerves occurs at the oxalosuccinate level and at the oxaloacetate level and that the rates of these fixations were almost the same. Thus the active backwards reaction from α-ketoglutaric acid to citric acid in lobster nerve was confirmed. It was also possible that both the activity of the citrate cleavage enxyme and the mixing of the dicarboxylic acid carboxyl groups were minimal. The concentration of oxaloacetic acid was estimated to be 2 mμmole/mg protein, or 4 mμmoles for a 50 mg nerve.

Electronic Resource

1432-1106

CO2 fixation ; citrate ; rabbit sciatic nerve

Springer Online Journal Archives 1860-2000

Medicine

Summary The extent of CO2 fixation in the sciatic nerve of the rabbit was determined. The specific activitiy of citric acid was higher than that of glutamic, aspartic, and malic acids, and the specific activity of citric acid obtained from the 2 hour incubation nerve was close to 1/3 of that of the CO2 in the medium. The ratio of the radioactivity of the C-6 to C-1 of citrate was about 2∶1 in intact nerves and about 1∶1 in damaged nerves, and the ratio of the radioactivitiy of C-4 to C-1 of aspartate was approximately 1∶1 in both cases. These results suggest that in the sciatic nerve of the rabbit: 1) the dicarboxylic acid “shuttle” was active, 2) the extent of the carboxylation at the oxalosuccinic acid level was 1/2 or more of that at the oxaloacetic acid level, and 3) the CO2 fixation by the carboxylation of a-ketoglutaric acid might have some relationship to nerve function. The significance of CO2 fixation, and the possible relationship between the carboxylation of α-ketoglutaric acid and the concentrations of citric acid, acetyl-CoA and acetylcholine, and the control of the rate of tricarboxylic acid cycle were discussed.

Electronic Resource

1573-6903

Springer Online Journal Archives 1860-2000

Medicine

Abstract GABA-transaminase has been found to be released from rat brain synaptosomes by halothane in a dose-related manner. The releases of both GABA-transaminase and succinic semialdehyde dehydrogenase were increased with time. The release of other enzymes (creatine kinase, glutamate decarboxylase, aspartate transaminase, lactate dehydrogenase, and malate dehydrogenase) was less in magnitude and not related to the duration of incubation. Such observations suggested a specific event in the halothane-induced release of GABA-catabolizing enzymes. A suggestion linking mode of anesthetic action to a mitochondrial effect of volatile anesthetics was made.

Electronic Resource