Search Results - (Author, Cooperation:M. Chi)

2018-04-03

Rockefeller University Press

0022-1007

1540-9538

Medicine

Innate Immunity and Inflammation

2018-07-17

The American Association for Cancer Research (AACR)

1078-0432

1557-3265

Medicine

2018-08-16

The American Association for Cancer Research (AACR)

1078-0432

1557-3265

Medicine

2015-07-25

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

2014-03-01

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

2018-05-26

American Physical Society (APS)

1098-0121

1095-3795

Physics

Electronic structure and strongly correlated systems

1089-7550

AIP Digital Archive

Physics

Optical constants and absorption data of thin iridium silicide films on silicon substrates are presented for incident light between 4 and 11 μm. The data were obtained from reflection and transmission measurements made on samples with IrSi thicknesses from 8 to 350 A(ring). The optical constants n and k are those that best fit the reflection and transmission data over the wavelength and thickness ranges.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

We present a detailed procedure for calculating confined energy levels of strained-layer GexSi1−x/Si valence-band quantum wells as a function of Ge concentration x and well width L. The method assumes noncoupled wells and takes into account strain and spin-orbit-induced band shifts and splitting. We illustrate the method and find the heavy-hole (hh), light-hole (lh), and spin-orbit split-off (so) subband energy levels for wells deposited on Si(001) and Si(111) oriented substrates. We show results for L=40 A(ring) and Ge concentrations between x=0.0 and x=0.8, and for composition x=0.25 and well widths between L=0.0 and L=100 A(ring). We plot (x,L) sets which give transition wavelengths between 10 and 11 μm, the central region of an atmospheric transmission window of interest to infrared detector applications. We find that hh ground to excited-state transitions are more sensitive to well width variations, whereas hh to lh or hh to so transitions are more composition dependent. There are (x,L) combinations which permit both hh ground to excited state and hh to lh transitions. Such regions may possess strong absorption cross sections both for excitation at normal incidence and for illumination at an angle. Energy levels for the two substrate orientations are qualitatively similar, but for Si(111) the corresponding transitions occur at smaller x and L. The smaller L minimizes strain relaxation effects.

Electronic Resource

1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Abstract— A total of 25 human brain tumors and 4 specimens of human brain were rapidly frozen at the time of operation and analyzed for ATP, ADP, AMP, UTP, total nucleoside triphosphates, P-creatine, creatine, inorganic P, creatine kinase, lipid and glycogen. Analyses were made on submicrogram samples dissected from frozen dried sections in order to obtain material as free as possible from admixture with brain, necrotic tissue, blood, etc. A method was developed to estimate the original water content of the frozen dried samples. The brain specimens contained five times as much glycogen as small mammal brains, otherwise the values were similar. The tumors were in fair to excellent energy status. Within the areas chosen for assay, most of ATP and total adenylate were substantially higher than in brain in the case of 5 out of 15 gliomas, 3 of 5 meningiomas, and 1 of 4 schwannomas. UTP was almost invariably higher and other nucleotide triphosphates (besides ATP and UTP) lower than in brain. Glycogen was extremely variable, ranging among the gliomas from 0.05% to 6% of dry wt (4 times the level in the human brains). Creatine plus P-creatine, compared to cerebral cortex levels, ranged from 15 to 85% in gliomas, was about 25% in meningiomas and the only medulloblastoma, and varied between 6 and 8% in the schwannomas. P-Creatine varied more or less in keeping with the energy status. Creatine kinase was exceedingly variable. It was almost zero in the schwannomas, the medulloblastomas, 3 of 5 meningiomas, and 2 of 15 gliomas, whereas in some of the gliomas the activity approached that found in brain.

Electronic Resource

1749-6632

Blackwell Publishing Journal Backfiles 1879-2005

Natural Sciences in General

Electronic Resource

1600-065X

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Electronic Resource

0885-2014

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Psychology

Electronic Resource

0038-1101

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Electrical Engineering, Measurement and Control Technology

Physics

Electronic Resource

0022-460X

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

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

Physics

Electronic Resource

0885-2014

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Psychology

Electronic Resource

1572-8935

Epoxy ; Blend ; Polycarbonate ; Transesterification

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

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

Physics

Abstract PC-DER331 blends are transparent and homogeneous due to the transesterification taking place during hot melting process. This transesterification reaction does not occur or occurs insignificantly during the preparation of PC-DER332 blends. PC is separated from the PC-DER332 melt mixture by slow cooling to room temperature but the mixture remains a single phase by quenching with an ice bath. Two systems of PC-epoxy blends, PC-DER331 blends and PC-DER332 blends are cured by the m-phenylene diamine (MPDA) in a stoichiometric ratio. Curing kinetics have been carried out by differential scanning calorimeter (DSC). The presence of PC accelerates the curing reaction. Infrared spectroscopy (IR) indicates the occurrence of transesterification in the PC-DER331/MPDA blends during curing. The flexural modulus increases with the increase of the PC content while the notched Izod impact strength decreases with the increase of the PC content for all the blending systems. The fracture surfaces of the PC-DER331/MPDA blends are smooth, an indication of a homogeneous morphology. The fracture surfaces of the PC-DER332/MPDA blends are rough, an indication of a heterogeneous morphology.

Electronic Resource

1572-8935

Fatigue behavior ; C.F./PEEK ; Composites ; Weibull distribution function ; Hygrothermal ; Impact

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

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

Physics

Abstract The hygrothermal effects on the fatigue behavior of the Carbon/PEEK laminated composites before and after impact damage were examined in this study. The [0/45/90/-45]2s AS-4/PEEK laminated composites were immersed in 80°C hot water for 45, 90 and 200 days,and subjected to falling weight impact with an energy of 8.58 J and then immersed in 80°C hot water for 45 days. It was found that the tensile strength of AS-4/PEEK laminated composites decreased with the increase of exposure period. The injured AS-4/PEEK composites were subjected to a static load and a tensiontension fatigue load at various levels of stress amplitudes. The effect of stress amplitude on the fatigue life was studied. The experimental fatigue life under different stress amplitude tests were estimated by the median rank order statistic cumulative distribution function. Then,the fitting curves for estimated data were analyzed by the Weibull distribution function. The S-N curves for a series of cyclic loads at various survival probabilities were presented. The damage behaviors of composites after fatigue load test were also investigated by scanning electron microscope(SEM). Results indicated the fatigue lives of immersed specimens were shorter than those without hygrothermal effect, the impact damage affects the fatigue life of composite significantly.

Electronic Resource

1435-1463

Amphetamine ; thyrotropin-releasing hormone ; fever ; aspirin ; adrenergic blockade ; thermoregulation

Springer Online Journal Archives 1860-2000

Medicine

Summary The mechanisms underlying the thermal effects induced by intrahypothalamic administration of either d-amphetamine or thyrotropin-releasing hormone (TRH) has been investigated in conscious rats. Direct administration of d-amphetamine (1–10μg in 1μl) or TRH (1–4μg in 1μl) into the preoptic anterior hypothalamus caused hyperthermia or fever at the ambient temperature (Ta∶ 8, 22 and 30 °C) studied. The fever induced by d-amphetamine or TRH was due to increased metabolic heat production at Ta 8 °C, while at Ta 30 °C the fever was due to cutaneous vasoconstriction in the rat. At Ta 22 °C, the fever was due to both increased metabolism and cutaneous vasoconstriction. Furthermore, the fever induced by intrahypothalamic administration of TRH was greatly reduced by pretreatment with intrahypothalamic administration of either yohimbine (a blocking agent of alpha-adrenergic receptors), phentolamine (a blocking agent of alpha-adrenergic receptors) or DL-propranolol (a blocking agent of beta-adrenergic receptors) in the rat. However, the fever induced by d-amphetamine was antagonized by pretreatment with yohimbine or phentolamine, but not with DL-propranolol in the rat. These observations indicate that the adrenergic receptor mechanisms within the hypothalamus are involved in the fever induced by both d-amphetamine and TRH.

Electronic Resource

1432-0649

PACS: 42.65.Hw; 42.70.Nq

Springer Online Journal Archives 1860-2000

Physics

eff and the electro-optic coefficient r33 in Ce-doped and Rh-doped BaTiO3 were determined by two-beam coupling measurements. It was found that the effective trap density Neff of BaTiO3:Ce increases whereas that of BaTiO3:Rh decreases with increasing temperature. The electro-optic coefficient r33 of both crystals increases with temperature. The photorefractive response times were also measured and found to decrease with different rates as temperature increases in the two crystals. The results were discussed by using the two-centre model for BaTiO3:Ce and three-charge-state model for BaTiO3:Rh. We found that the different temperature dependence of Neff in the two crystals was due to the fact that the deep- and shallow-trap levels in BaTiO3:Ce are caused by different impurity centres whereas those in BaTiO3:Rh are caused by different charge states of the same impurity centre.

Electronic Resource

1432-0649

PACS: 42.65.Hw; 42.70.Nq

Springer Online Journal Archives 1860-2000

Physics

Abstract. Impurity levels, light-induced and thermo-induced charge transfer processes in Rh-doped and Ce-doped photorefractive BaTiO3 were studied. The thermal depths and optical transitions of these impurity levels in the crystals were determined by using such methods as light-induced absorption, thermo-induced absorption, and grating dark decay. The origins of these impurity levels were discussed. We demonstrated, for the first time to our knowledge, that thermo-induced absorption spectroscopy is a useful and complementary technique for investigating the impurity levels in photorefractive crystals. With this technique, the deep impurity level generated by Ce in BaTiO3:Ce was revealed and identified.

Electronic Resource