Quantitative analysis on swelling behavior of HSMA/PVA IPN ionic gels under electric field

In order to explain the electric response of HSMA/PVA IPN ionic gel, polyion concentration (0 and/or interaction parameter (x_ij) between gel and water are used, which were previouslydetermined elsewhere by comparing swelling behaviours in the mixed solvents with Tanaka’s theory [1], Ionic polymer gel separated from the electrodes exhibits exponential responses when the electric field is applied or stopped, where the characteristic times for swelling and shrinking and equilibrium swelling ratio are successfully correlated with polyion concentration or interaction parameter. In addition, the strength of field is also an important factor to determine the overall responses. The direction of gel with respect to the electric field is also considered and optimum size was apparent to show maximum swelling.     

Novel mutants define genes required for the expression of human histocompatibility leukocyte antigen DM: evidence for loci on human chromosome 6p

We and others have shown that the products of the HLA-DM locus are required for the intracellular assembly of major histocompatibility complex class II molecules with cognate peptides for antigen presentation. HLA-DM heterodimers mediate the dissociation of invariant chain (Ii)-derived class II-associated Ii peptides (CLIP) from class II molecules and facilitate the loading of class II molecules with antigenic peptides. Here we describe novel APC mutants with defects in the formation of class II-peptide complexes. These mutants express class II molecules which are conformationally altered, and an aberrantly high percentage of these class II molecules are associated with Ii-derived CLIP. This phenotype resembles that of DM null mutants. However, we show that the defects in two of these new mutants do not map to the DM locus. Nevertheless, our evidence suggests that the antigen processing defective phenotype in these mutants results from deficient DM expression. These mutants thus appear to define genes in which mutations have differential effects on the expression of conventional class II molecules and DM molecules. Our data are most consistent with these factors mapping to human chromosome 6p. Previous data have suggested that the expression of DM and class II genes are coordinately regulated. The results reported here suggest that DM and class II can also be differentially regulated, and that this differential regulation has significant effects on class II-restricted antigen processing.     

A process for production of porous elements with an asymmetric structure for tangential microfiltration of liquid media

A process for production of asymmetric porous structures of filtering elements by the method of vibration molding of a mixture of powders with different granulometric compositions is described. Theoretical and experimental curves of segregation modes versus vibration parameters are given. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 70, No. 3, pp. 362–367, May–June, 1997.     

Establishing a link between oncogenes and tumor angiogenesis

We have tried to stress that mutant oncogenes or overexpressed, nonmutated proto-oncogenes, in addition to their direct affect on promoting aberrant tumor cell proliferation (and survival), may possess a crucial indirect means of stimulating tumor cell growth through regulation of angiogenesis. This effect would never be observed in tissue culture studies of oncogene function using pure cultures of tumor cells, which probably helps explain why the pro-angiogenic function of oncogenes has not been appreciated until only relatively recently. Indeed, the very first indication of a possible contributory role of oncogenes, such as ras and myc, to tumor angiogenesis was first reported by Thompson et al. in 1989, who used reconstituted organ cultures of the mouse prostate gland for their studies (69). This potentially important contribution of oncogenes to tumor growth and development may prove to have an impact on how various signal transduction inhibitors that are now in early phase clinical trials, e.g., monoclonal neutralizing antibodies to the human EGF receptor (70), function in vivo as anti-tumor agents.     

Determination of molecular weight and its distribution of flexible chain polymer by phase-modulated flow birefringence technique

The objective of this study is to develop a systematic method to determine molecular weight and its distribution of flexible chain polymer by birefringence experiments. Using the random walk model, birefringence δn and orientation angle ξ have been optically obtained as functions of molecular weights. To confirm the theory, polystyrene solutions with different molecular weights dissolved in polychlorinated biphenyl were experimented by the phase-modulated flow birefringence (PMFB) method. Birefringence of polystyrene solutions is proportional to (Σc _i M _i ^1.6 )γ², and cot(2χ) to (Σc _i M _i ^1.6 /B₁Σc _i M _i ^−0.2 )γ. The experimental results agreed well with the theoretical predictions proposed in this study.     

An SLA-based Broker for Cloud Infrastructures

The breakthrough of Cloud comes from its service oriented perspective where everything, including the infrastructure, is provided “as a service”. This model is really attractive and convenient for both providers and consumers, as a consequence the Cloud paradigm is quickly growing and widely spreading, also in non commercial contexts. In such a scenario, we propose to incorporate some elements of volunteer computing into the Cloud paradigm through the Cloud@Home solution, involving into the mix nodes and devices provided by potentially any owners or administrators, disclosing high computational resources to contributors and also allowing to maximize their utilization. This paper presents and discusses the first step towards Cloud@Home: providing quality of service and service level agreement facilities on top of unreliable, intermittent Cloud providers. Some of the main issues and challenges of Cloud@Home, such as the monitoring, management and brokering of resources according to service level requirements are addressed through the design of a framework core architecture. All the tasks committed to the architecture’s modules and components, as well as the most relevant component interactions, are identified and discussed from both the structural and the behavioural viewpoints. Some encouraging experiments on an early implementation prototype deployed in a real testing environment are also documented in the paper.     

New trends in powder injection moulding

Powder injection moulding (PIM) is a rapidly growing technology for producing complex geometry, net shaped components from ceramics, metals, hard metals, and intermetallics. The shaping of ceramic powders using injection moulding has a highly creative aspect with regard to the complexity of the structural parts. This permits the most near-net shaping possible. Therefore, costly finishing of the sintered components can be reduced to a minimum or totally eliminated. This potential for ceramic injection moulding (CIM) has led in the recent past to intensified international research and development activities. A number of new binder systems have been developed, i.e., polyacetate based, PEG-polymer based, acrylic-polymer based, agarose-based, etc. The development in the area of new binder composition was in parallel assisted by a significant improvement in debinding processes. New debinding systems have been developed, i.e., computer assisted thermal debinding, extraction debinding, catalytic debinding, or even freeze drying or microwave assisted drying, which significantly shortened the debinding time from days to hours and lowered the emission of undesirable volatile organic by-products to a minimum. The formation of defects during the debinding process was also practically eliminated. Nitherlands Enegy Research Foundation ECN. Published in Poroshkovaya Metallurgiya, Nos. 3–4(406), pp. 16–23, March–April, 1999.     

UHF Propagation in Caves and Subterranean Galleries

An experimental study is described on the natural propagation of UHF band radio waves in straight subterranean galleries. An extensive measurement project took place in five underground localities and, based on the experimental data, an empirical model of radio wave transmission was derived. The model was calibrated according to the measurement data and compared with the theoretical waveguide approach to propagation prediction. The presented results can be used for the practical planning of wireless communications in speleology applications and as an experimental basis for further theoretical works     

Effect of heat treatment on PtRu/C catalyst for methanol electro-oxidation

The effect of heat treatment on a commercial PtRu/C catalyst was investigated with a focus on the relationship between electrochemical and surface properties. The heat treated PtRu/C catalysts were prepared by reducing the commercial PtRu/C catalyst at 300, 500, and 600 °C under hydrogen flow. The maximum mass activity for the methanol electro-oxidation reaction (MOR) was observed in the catalyst heat treated at 500 °C, while specific activity for the MOR increased with increasing heat treatment temperature. Cyclic voltammetry (CV) results revealed that the heat treatment caused Pt rich surface formation. The increase in surface Pt was confirmed by X-ray photoelectron spectroscopy; the surface (Pt:Ru) ratio of the fresh catalyst (81:19) changed to (87:13) in the 600 °C heat treated catalyst. Quantitative analysis of the Ru oxidation state showed that the ratio of metallic Ru increased with an increase in heat treatment temperature. On the other hand, RuO_xH_y completely reduced at 500 °C and the ratio of RuO₂ slightly decreased with increasing heat treatment temperature.