Chelated alkoxyalumoxanes and a silica-free binder based on them

Chelated alkoxyalumoxane oligomers have been synthesized through consecutive hydrolysis and alcoholysis of organoaluminum compounds stabilized by compounds capable of keto-enol tautomerism. The chelated alkoxyalumoxanes were used to prepare a silica-free binder for the fabrication of heat-resistant (up to 2050°C), chemically inert corundum ceramic composites. The likely structures of the synthesized preceramic alumoxane oligomers were inferred from physicochemical characterization results (¹H, ¹³C, and ²⁷Al NMR, IR spectroscopy, mass spectrometry, gel-permeation chromatography, thermal analysis, and elemental analysis).     

Possibility of Using a High-Pressure Pneumatic Pump in the Porcelain Industry

The advantages and disadvantages of using a high-pressure pneumatic pump at porcelain and insulator works are discussed. The testing results of a prototype pump are described.     

Synthesis and biological studies on analogs of cyclolinopeptide A with a shortened peptide chain

Continuing our work on the immunosuppressive activity of cyclolinopeptide A (CLA), a cyclic nonapeptide of the sequence: c-(-Leu-Ile-Ile-Leu-Val-Pro-Pro-Phe-Phe), we synthesized a series of 6 linear analogs of CLA, successively shortened at the N-terminus of the peptide chain. Immunosuppressive activity of acetates as well as trifluoroacetates of these peptides was investigated using PFC (humoral immunity) and DTH (cellular immunity) tests. It was found that the immunosuppressive potency of the peptides examined diminishes with shortening of the peptide chain. Octapeptide I with the sequence Ile-Ile-Leu-Val-Pro-Pro-Phe-Phe was found to be the most active of the whole series. The immunosuppressive activity increased again for a tripeptide fragment of CLA of the sequence Pro-Phe-Phe. The immunosuppressive activity of octapeptide probably depends on the suppression of IL-1, IL-6 and TNF production by the cells involved in immune and inflammatory response.     

Threshold voltage-minimum gate length trade-off in buried channelPMOS devices for scaled supply voltage CMOS technologies

The trade-off between threshold voltage (V_th) and the minimum gate length (L_min) is discussed for optimizing the performance of buried channel PMOS transistors for low voltage/low power high-speed digital CMOS circuits. In a low supply voltage CMOS technology it is desirable to scale V_th and L_min for improved circuit performance. However, these two parameters cannot be scaled independently due to the channel punch-through effect. Statistical process/device modeling, split lot experiments, circuit simulations, and measurements are performed to optimize the PMOS transistor current drive and CMOS circuit speed. We show that trading PMOS transistor V_th for a smaller L_min results in faster circuits for low supply voltage (3.3 to 1.8 V) n⁺-polysilicon gate CMOS technology, Circuit simulation and measurements are performed in this study. Approximate empirical expressions are given for the optimum buried channel PMOS transistor V _th for minimizing CMOS circuit speed for cases involving: (1) constant capacitive load and (2) load capacitance proportional to MOS gate capacitance. The results of the numerical exercise are applied to the centering of device parameters of a 0.5 μm 3.3 V CMOS technology that (a) matches the speed of our 0.5 μm 5 V CMOS technology, and (b) achieves good performance down to 1.8 V power supply. For this process the optimum PMOS transistor V_th (absolute value) is approximately 0.85-0.90 V     

Highly efficient ceramic catalytic blocks with a honeycomb structure

Compositions and technologies are suggested for preparing highly efficient catalyst blocks with a honeycomb structure to be used for reducing nitrogen oxides with ammonia in flue gases from thermal power plants. The blocks have high structural strength and catalytic activity.     

Clonal analysis of peripheral blood lymphocytes from three patients with advanced neuroblastoma receiving recombinant interleukin-2 and interferon alpha

Cultures of both isolated and conjugated explants from early gastrulae of Bufo arenarum were prepared for a study of the development of ventral mesoderm. Only combinations including components of the deep ventral marginal zone and the animal pole successfully differentiated into blood cells (erythrocytes). Histological studies indicated that, while prospective mesodermal cells constituted the only source of such cells, prospective ectodermal cells provided the necessary stimulus for this kind of differentiation. Differentiated cultures, in which the tracer of cell-lineage fluorescein dextran amine was used to label these components, confirmed the above conclusions. These findings are discussed in the context of current concepts about the formation of mesoderm.     

Improving the emf and dc voltage measuring system (discussion paper)

The concept of a new system of emf and dc voltage measurements is and methods of its implementation capable to satisfy the predicted demands of the Russian economy for 2003–2010 are proposed as a matter of discussion. Translated from Izmeritel'naya Tekhnika, No. 10, pp. 34–37, October, 1998.