7 resultados para 100-250 µm
em Brock University, Canada
Resumo:
Pressure variations of the superconducting transition temperature Ic of a series of amorphous NixZr 1 OO-x alloys have been studied under quasmydrostatic pressures upto 8 G Pa. For amorphous samples having Ni-concentration less than 40%, i)Tc/dP is positive in sign and it decreases non linearly with increase in I. whereasdTcldP is negative in sign for Ni concentration of 45%. Comparison with the Hall coefficient (I) and the thermoelectric power (2) results for the same amorphous alloys leads to the conclusion that s-d hybridization nature of the d-band (Nil plays a central role in the sign reversal behaviour. Application of pressures greater than 2 G Pa to Ni20ZrgO led to the formation of a new phase, w-Zr. which retains its form after the pressure is released.
Resumo:
Resveratrol, a polyphenol found in red wine, has been reported to have
antithrombotic, antiatherogenic, and anticancer properties both in vitro and III VIVO.
However, possible antidiabetic properties of resveratrol have not been examined. The
objective of this study was to investigate the direct effects of resveratrol on basal and
insulin-stimulated glucose uptake and to elucidate its mechanism of action in skeletal
muscle cells. In addition, the effects of resveratrol on basal and insulin- stimulated amino
acid transport and mitogenesis were also examined.
Fully differentiated L6 rat skeletal muscle cells were incubated with resveratrol
concentrations ranging from 1 to 250 IlM for 15 to 120 min. Maximum stimulation, 201
± 8.90% of untreated control, (p<0.001), of2eH] deoxy- D- glucose (2DG) uptake was
seen with 100 IlM resveratrol after 120 min. Acute, 30 min, exposure of the cells to 100
nM insulin stimulated 2DG uptake to 226 ± 12.52% of untreated control (p<0.001). This
appears to be a specific property of resveratrol that is not shared by structurally similar
antioxidants such as quercetin and rutin, both of which did not have any stimulatory
effect. Resveratrol increased the response of the cells to submaximal insulin
concentrations but did not alter the maximum insulin response. Resveratrol action did not
require insulin and was not blocked by the protein synthesis inhibitor cycloheximide.
L Y294002 and wortmannin, inhibitors of PI3K, abolished both insulin and resveratrolstimulated
glucose uptake while phosphorylation of AktlPKB, ERK1I2, JNK1I2, and p38
MAPK were not increased by resveratrol. Resveratrol did not stimulate GLUT4
transporter translocation in GLUT4cmyc overexpressing cells, in contrast to the
significant translocation observed with insulin. Furthermore, resveratrol- stimulated glucose transport was not blocked by the presence of the protein kinase C (PKC)
inhibitors BIMI and G06983. Despite that, resveratrol- induced glucose transport
required an intact actin network, similar to insulin.
In contrast to the stimulatory effect seen with resveratrol for glucose transport,
e4C]methylaminoisobutyric acid (MeAIB) transport was inhibited. Significant reduction
of MeAIB uptake was seen only with 100uM resveratrol (74.2 ± 6.55% of untreated
control, p<0.05), which appeared to be maximum. In parallel experiments, insulin (100
nM, 30 min) increased MeAIB transport by 147 ± 5.77% (p<0.00l) compared to
untreated control. In addition, resveratrol (100 JlM, 120 min) completely abolished
insulin- stimulated amino acid transport (103 ± 7.35% of untreated control,p>0.05).
Resveratrol also inhibited cell proliferation in L6 myoblasts with maximal
inhibition of eH]thymidine incorporation observed with resveratrol at 50 J.LM after 24
hours (8 ± 1.59% of untreated control, p
Resumo:
We examine stock market reactions around the Nasdaq-100 Index reconstitutions. We find a symmetric and transitory price response accompanied by a significant increase in trading volume on the effective date. Firms added to the Nasdaq-100 Index experience significant increases in institutional ownership, the number of market makers, and the number of shareholders. In contrast, firms removed from the index show significant decreases in the number of institutional shareholders. Additions to the Nasdaq-100 Index also show significant increases in four liquidity measures, whereas deletions demonstrate significant decreases in two liquidity measures. These changes in liquidity are related to the abnormal return on the announcement day. Taken together, the results suggest support for the price pressure, liquidity, and investor awareness hypotheses.
Resumo:
Legal provisions in the US have extended the idea of the border to the inside of US territory. Border Patrol Agents confront people in different spaces to inquire about their status. I examine border policing along the northern border of the United States through textual and discourse analysis. This thesis asks: How do border agents exercise power and control the movement of people within 100 miles of the border? In whose interest is the border, the “nation,” secured? The spaces in which these mobile borders are practiced become the sites where “citizens” and “aliens” are produced, reproduced and contested. These border policing practices create the illusion of a “nation” that is secured for “our” interests. However, the interests of these vulnerable groups are not reflected in the immigration policy and along the “border. Therefore the very existence of immigrants and their basic right to be in the US is undermined.
Resumo:
The synthesis and studies of two classes of poly dentate ligands are presented as two projects. In project 1, four new carboxamide ligands have been synthesised via the condensation of 2,2',6,6'-tetrachloroformyl-4,4'-bipyridine or 2,6-dichloroformyl pyridine together with heterocyclic amines containing pyridine or pyrazole substituents. The coordination chemistry of these ligands has been investigated and studies have shown that with a Cu(II) salt, two carboxamide ligands LJ and L2 afford large clusters with stoichiometries [Cu8(L1)4Cl16].CHCl3.5H2O.7CH3OH (I) and [Cu9(L2)6Cl6].CH3OH.5H2O.(C2H5)3N (II) respectively. [molecular diagram availabel in pdf]. X-ray diffraction studies of cluster (I) reveal that it has approximate S4 symmetry and is comprised of four ligands and eight copper (II) centers. Here, coordination takes place via amide 0 atoms, and pyrazole nitrogens. This complex is the first reported example of an octanuclear copper cluster with a saddle-shaped structure. The second cluster comprises nine copper ions that are arranged in a cyclic array. Each ligand coordinates three copper centers and each copper ion shares two ligands to connect six ligands with nine copper ions. The amide nitrogens are completely deprotonated and both amide Nand 0 atoms coordinate the metal centres. The cluster has three-fold symmetry. There are six chloride ions, three of which are bridging two neighbouring Cu(II) centres. Magnetic studies of (I) and (II) reveal that both clusters display weak antiferromagnetic interactions between neighbouring Cu(II) centers at low temperature. In the second project, three complexes with stoichiometries [Fe[N302](SCN)2]2 (III), R,R-[Fe[N3O2](SCN)2 (IV) and R,R-]Fe[N3O2](CN)2] (V) were prepared and characterized, where [N302] is a pentadentate macrocycle. Complex (III) was prepared via the metal templated Schiff-base condensation of 2,2',6,6'-tetraacetyl-4,4'-bipyridine together with 3,6-dioxaoctane-I,8-diamine and comprises of a dimeric macro cycle where the two Fe(II) centres are in a pentagonal-bipyramidal environment with the [N302] ligands occupying the equatorial plane and two axial NCS ligands. Complexes (IV) and (V) were prepared via the condensation of 2,6-diacetylpyridine together with a chiral diamine in the presence of FeCh. The synthetic strategy for the preparation of the chiral diamine (4R,5R)-4,5-diphenyl-3,6-dioxa-I,8-octane-diamine was elucidated. The chirality of both macrocycles (IV) and (V) was probed by circular dichroism spectroscopy. The crystal structure of (IV) at 200 K contains two independent molecules in the unit cell, both of which contain a hepta-coordinated Fe(II) and axial NCS ligands. Variable temperature magnetic susceptibility and structural studies are consistent with a high spin Fe(II) complex and show no evidence of any spin crossover behaviour. In contrast, the bis cyanide derivative (V) crystallizes with two independent molecules in the unit cell, both of which have different coordination geometries consistent with different spin states for the two Fe(II) centres. At 250 K, the molecular structure of (V) shows the presence of both 7- and a 6-coordinate Fe(II) complexes in the crystal lattice. As the temperature is lowered, the molecules undergo a structural change and at 100 K the structural data is consistent with a 6- and 5-coordinate Fe(II) complex in the unit cell. Magnetic studies confirm that this complex undergoes a gradual, thermal, spin crossover transition in the solid state. Photomagnetic measurements indicate this is the first chiral Fe (II) sea complex to exhibit a LIESST.
Resumo:
Indenture stating that Joseph A. Woodruff, sheriff, is paid $100 by S.D. Woodruff for half interests in the cottage and its furnishings situated at the club in Long Point, Lake Erie and is now in possession jointly with R. Lucas of Hamilton. This is signed by Joseph A. Woodruff, Jan. 23, 1886.