Analysis of explosives by nuclear magnetic resonance spectrometry

In order to evaluate the applicability of NMR to the analysis of explosives, the method was used to analyse explosives from actual cases. The results were then compared with results from other analytical methods, mainly TLC and GC/MS. For unexploded samples NMR was found to be a simple, fast and reliable method, often allowing the identification of mixtures without pre-separation. Some post-explosion samples were also successfully analysed by NMR. Although sensitivity problems still exist, NMR showed a surprisingly promising prospects for the difficult field of post-explosion analysis.     

Fluidic Assembly of Optical Components

A self-assembly technique is used to match microscopic components in a desired configuration with a high degree of precision. The basis of this self-assembly technique is capillary forces that are used to assemble the micro components. A liquid solder provides the capillary forces by wetting a 3-D cavity in each of the parts to be assembled. An advantage of the proposed design is that the high degree of precision of the mating feature relative to the optical guides ensures a high degree of concentricity of the optical path in the device. The application presented is the self-assembly of arrays of single-mode optical fibers onto an optical chip for use in optical switches or tunable filters. Optical measurements revealed an insertion loss of less than 0.85 dB, which demonstrates misalignment in the order of 1 mum     

Far-field distribution of semiconductor phase-locked arrays with multiple contacts

Experimental results of far-field patterns of semiconductor laser arrays with multiple contacts are reported. It is found that, by tailoring the distribution of the currents through the array elements, narrow single-lobe patterns?which are more useful in most applications?can be obtained from arrays that usually operate in a double-lobe mode. A diffraction-limited 1.8°-wide far-field pattern was obtained from a three-element array.     

Epitaxial growth of silicon-germanium single crystals

The problems associated with obtaining single crystals of silicon-germanium with comparable concentrations of the two elements, are discussed. Epitaxial growth from the vapour phase was found to be much more suitable than growth from the melt, which yielded crystals with gross inhomogeneities, even when only 3% of Ge was included. By using a modified epitaxial system which is described, Si-Ge single crystal layers of up to 32% Ge were grown succesfully. It was found that growth temperature must be reduced with increased Ge content for optimum results. The measured growth rate was a function of both the temperature and the molar ratio of Si to Ge in the gas phase.     

Apoptosis of bovine ovarian surface epithelial cells by Fas antigen/Fas ligand signaling

Ovarian surface epithelial cells (OSEs), a single layer of cells that cover the surface of the ovary, undergo turnover at the site of follicular rupture at ovulation. Greater than 90% of ovarian cancers arise from the OSEs. The objective of this study was to determine whether OSEs have the capacity to regulate their own demise through expression of Fas antigen (Fas) and Fas ligand (FasL) and activation of Fas-mediated apoptosis. In initial experiments, primary cultures of bovine OSEs responded to treatment with recombinant FasL by undergoing apoptosis. The percentage of cell death was not affected by the presence or absence of serum in the media or by co-treatment with interferon-gamma, a treatment shown to potentiate Fas-mediated apoptosis in a number of cell types. Subsequent experiments tested the ability of stress-inducing drugs, anisomycin and daunorubicin, to promote apoptosis by stimulating an endogenous Fas-FasL pathway in OSEs. Treatment with FasL, anisomycin or daunorubicin induced cell death and this was suppressed by co-treatment with a peptide inhibitor of caspases, ZVAD. Treatment with anisomycin or daunorubicin in the presence of ZVAD increased expression of FasL mRNA and protein but did not alter expression of Fas mRNA or protein. Treatment of OSEs with a recombinant protein that blocks interaction of FasL with Fas (Fas:Fc) reduced apoptosis in response to anisomycin and daunorubicin, indicating that drug-induced apoptosis was mediated at least partially through endogenous Fas-FasL interactions. In summary, OSEs undergo apoptosis in response to stress-inducing drugs through activation of an endogenous Fas pathway.     

Planning allocations and the stubborn north–south divide in Tel Aviv–Jaffa

Several master plans have attempted to lessen the divide between the poor southern neighborhoods of Tel Aviv–Jaffa and the well-off central and northern ones. We compared the planning visions, the main policies and detailed schemes, financing methods, and actual implementation efforts. We found that each planning generation has promoted different development locations, regulations, and allocation methods, and yet implementation has generally been much more durable and with superior socio-spatial impacts in the more affluent areas. To analyze and explain these findings we studied planning allocations in the light of ideas of distributive justice and of urban regime practice. We found that while the welfare state's direct allocation of housing and infrastructure for communities and individuals was not really equal, the later indirect allocations by neoliberal regimes mainly stimulated market forces in the more affluent or attractive areas. We also found that while planning allocation varied in different neighborhoods, the pace and order of planning and realization became crucial elements in urban inequality.