西藏喜马拉雅山边缘的地壳结构及其变化

西藏雅鲁藏布江缝合线南部壳—幔边界的广角反射剖面,揭示了喜马拉雅山之北连续莫霍界面的深度(70公里),而向前莫霍界面的深度要浅15公里.再往南从35公里深度来的反射波是来自印度半岛的莫霍界面.     

Single-layer cylindrical compaction

In VLSI compaction, an array composed of a single cell warrants special consideration. Standard methods of compaction [MS] result in either nonuniform cell layouts or unnecessarily large cell spacing. These inadequacies would be lessened were the array compacted instead by compacting a single instance of the cell against itself: in essence, the cell would be compacted on a torus. Equivalently, the problem becomes that of compacting a layout to fit into a minimal area shape 4-tiling the plane.Only the one-dimensional version of the problem has been addressed: that equivalent to compaction on a cylinder. Unfortunately, the efficient longest-path approach to one-dimensional compaction is not directly applicable since there is no origin to compact against. Eichenberger and Horowitz solve the problem in polynomial time by using a min-cost flow approach to assign positions to the nodes of a constraint network embedded on a cylinder [EH]. Mehlhorn and Rülling found an iterative approach running in timeO(n ² logn) when restricted to networks abstracted from layouts having any fixed number of layers [MR]. In this paper the longest-path approach is adapted to solve the same cylindrical compaction problem on planar networks—those abstracted from single-layer layouts—in justO(n logn) time.This research was supported by NSF Presidential Young Investigator Grant MIP-8657693.     

In vivo compartmental metabolism of13C docosahexaenoic acid,studied by gas chromatography-combustion isotope ratio mass spectrometry

The exchange of docosahexaenoic acid (22:6n-3) within lipid pools in rat and human has been followed as a function of time after the ingestion of triglycerides (TG) containing 22:6n-3 labeled with¹³C(¹³C 22:6n-3). The¹³C abundance in the fatty acid was measured by gas-chromatography-combustion isotope ratio mass spectrometry which allowed the detection of 0.001 atom¹³C percent¹²C. The¹³C 22:6n-3 appearance was rapid in the TG of very low density lipoprotein plus chylomicron fraction, in which the maximal labeling was observed at 3 and 2 h after ingestion in rat and human, respectively. Concomitant with the TG utilization of this fraction by lipoprotein lipase from tissues, unesterified¹³C 22:6n-3 appeared in the plasma albumin.¹³C 22:6n-3 bound to albumin was mostly present in unesterified form before 12 h post-ingestion while after that period, lysophosphatidylcholine (lysoPC) bound to albumin carried higher¹³C 22:6n-3 concentrations. These lyso-PC were mostly from hepatic origin and might represent a potential source of 22:6n-3 redistribution to tissues. The¹³C 22:6n-3 uptake into rat brain PC and phosphatidylethanolamine was still increasing when the concentration of plasma unesterified¹³C 22:6n-3 had already dropped to a minimal plateau value and during the period of maximal plasma circulation of¹³C 22:6n-3-lysoPC bound to albumin. In contrast, the uptake of¹³C 22:6n-3 into blood platelet PC occurred during the phase of important circulation of¹³C-22:6n-3 bound to albumin, suggesting thein vivo efficiency of the Lands pathway for this fatty acid. It is concluded that¹³C 22:6n-3 esterified in TG is rapidly absorbed and redistributed within plasma lipoproteins and that its redistribution within the two lipid species bound to albumin might influence its uptake by platelets and rat brain.     

Observational learning and the effects of model-observer similarity.

This study examined the effects of similarity in competence between model and observer on the effectiveness of observational learning in argumentative writing. Participants ( N=214, 8th grade, mixed ability) were assigned to 1 of 3 conditions: an observation/weak-focus, an observation/good-focus, or a control condition. The two observational-learning groups observed pairs of peer models performing writing tasks. Participants focused respectively on the noncompetent (weak) model or on the competent (good) model. The control group performed the writing tasks themselves. Results are consistent with the similarity hypothesis: Weak learners learn more from focusing their observations on weak models, whereas better learners learn more from focusing on good models. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Influence of Oxygen Vacancies on the Electronic Structure of Yttrium Oxide

The influence of oxygen vacancies on the electronic structure of yttrium oxide was investigated both experimentally and theoretically. By means of X-ray absorption spectroscopy, at the yttrium K and L ₁₁ edges and at the oxygen K edge, information on the local densities of states of various orbital symmetries, around each type of atom, was obained. The total density of states in the valence band was studied using X-ray photoelectron spectroscopy. Experimental results were compared with those obtained on stoichiometric yttria. The evolution of the densities of states is well reproduced by self-consistent, semiempirical tight-binding calculations applied to clusters of increasing size, in which oxygen vacancies are introduced. The charge transfer between oxygen and yttrium is modified, as experimentally observed from the study of the O KLL Auger line shape. The decrease of the local atomic charge on oxygen is theoretically confirmed by the tight-binding calculations, showing a tendency toward a more covalent bond in nonstoichiometric yttria.     

Isolation and characterization of anti-FcgammaRIII (CD16) llama single-domain antibodies that activate natural killer cells

FcgammaRIII (CD16) plays an important role in the anti-tumor effects of therapeutic antibodies. Bi-specific antibodies (bsAbs) targeting FcgammaRIII represent a powerful alternative to the recruitment of the receptor via the Fc fragment, but are not efficiently produced. Single-domain antibodies (sdAbs) endowed with many valuable structural features might help to bypass this problem. In the present work, we have isolated anti-FcgammaRIII sdAbs (C21 and C28) from a phage library generated from a llama immunized with FcgammaRIIIB extra-cellular domains. These sdAbs bind FcgammaRIIIA+ NK cells and FcgammaRIIIB+ polymorphonuclear cells, but not FcgammaRI+ or FcgammaRII+ cells, as detected by indirect immunofluorescence. Competition experiments showed that C21 and C28 sdAbs bind different FcgammaRIII epitopes, with C21 recognizing a linear and C28 a conformational epitope of the receptor. Surface plasmon resonance experiments showed that C21 and C28 sdAbs bind FcgammaRIII with a K(D) in the 10 and 80 nM range, respectively. Importantly, the engagement by both molecules of FcgammaRIIIA expressed by transfected Jurkat T cells or by NK cells derived from peripheral blood induced a strong IL-2 and IFN-gamma production, respectively. These anti-FcgammaRIII sdAbs represent versatile tools for generating bsAbs under various formats, able to recruit FcgammaRIII killer cells to target and destroy tumor cells.     

Adhesion of Campylobacter jejuni and Mycobacterium avium onto polyethylene terephtalate (PET) used for bottled waters

Adhesion of the bacteria Campylobacter jejuni and Mycobacterium avium onto polyethylene terephtalate (PET), a polymer widely used within the bottled water industry was measured in two different groundwater solutions. From this, it was found that whilst the percentage cell adhesion for a given strain did not change between groundwater types, substantial variation was obtained between the two bacterial species tested: M. avium (10-30% adhered cells) and C. jejuni (1-2%) and no major variations were measured as a function of groundwater composition for a given strain. To explain this, the interfacial electro-hydrodynamic properties of the bacteria were investigated by microelectrophoresis, with the resultant data analysed on the basis of electrokinetic theory for soft biocolloidal particles. The results obtained showed that M. avium carries a significant volume charge density and that its peripheral layer exhibits limited hydrodynamic flow permeation compared to that of C. jejuni. It was also demonstrated that steric hindrance to flow penetration and the degree of hydrophobicity within/of the outer bacterial interface are larger for M. avium cells. In line with this, the larger amount of M. avium cells deposited onto PET substrates as compared to that of C. jejuni can be explained by hydrophobic attraction and chemical binding between hydrophobic PET and outer soft surface layer of the bacteria. Hydrophobicity of PET was addressed by combining contact angle analyses and force spectroscopy using CH₃-terminated AFM tip.