Effect of thiourea dioxide on the dynamics of continuous homophase synthesis of fibre-forming copolymers of acrylonitrile,methyl acrylate,and 2-acrylamido-2-methylpropanesulfonic acid

The effect of thiourea dioxide on the dynamics of homophase synthesis of copolymers of acrylonitrile, methyl acrylate, and 2-acrylamido-2-methylpropanesulfonic acid in 51.5% aqueous solution of NaSCN was investigated and its role in decreasing the induction period of the process was demonstrated. The effect of the synergism of 2-acrylamido-2-methylpropanesulfonic acid and thiourea dioxide, which reduces the induction period of synthesis, was established.Translated from Khimicheskie Volokna, No. 6, pp. 31–35, November–December, 1994.     

Technological aspects of fabrication of microfibres. A review

It was shown that in selecting the parameters for high-speed spinning of microfibres, it is necessary to consider the rheological factors that affect extrusion and stretching of the filaments. Technological schemes for fabrication of polyester microfibres are examined. Translated from Khimicheskie Volokna, No.5, pp. 13–17, September–October, 1998.     

Interaction of mass exchange and jet tension in spinning of nitron fibres

The reciprocal effect of mass exchange and tension of spun Nitron fibre in the spinning bath was demonstrated. The concentration region of the concentration of solvent in the spinning bath which guarantees attaining high elasticity and a strength of 100 cN/tex and the more finished fibre with a linear density of 0.01 tex was established.Nitron Plant, Novoiazot Industrial Association, Uzbekistan; Mogilev Institute of Technology, Belarus'. Translated from Khimicheskie Volokna, No. 6, pp. 41–43, November–December, 1993.     

Fabrication and prospects for the development of polyester microfibres (review)

One of the promising trends in the development of textile fibres — the creation of technology and equipment for production of microfibres which makes it possible to obtain comfortable new materials was analyzed. The technological characteristics of fabrication of microfibres with two levels of filament linear density were examined: 0.1–0.03 tex by high-speed spinning (HSS) using special techniques, and 0.03–0.002 tex with sector structure based on two-component systems. The stable tendency toward development of new techniques for thinning filaments to create a new generation of textile materials was pointed out.All-Russian Scientific-Research Institute of Synthetic Fibres, Tver'. Translated from Khimicheskie Volokna, No. 3, pp. 3–10, May–June, 1995.     

Evidence that deficient IFN-gamma production is a biological basis of herpes simplex virus type-2 neurovirulence

Although immune response control of herpes simplex virus (HSV) has been well demonstrated, numerous HSV-2 strains are neurovirulent in immunocompetent mice. Using an RNase protection assay and an ELISA, we found that HSV-2-infected mice exhibited a deficient IFN-gamma response, an inability to clear virus, and eventual death. An HSV-based amplicon vector expressing mouse IFN-gamma was constructed and packaged into HSV-1-helper virus (HSV(pIFN-gamma)). In mice treated with HSV(pIFN-gamma), (i) the LD50 of HSV-2(G) increased 5000-fold, (ii) intracerebral IFN-gamma expression increased 10-fold, and (iii) HSV titer rapidly decreased. We suggest that the deficient IFN-gamma response is a basis for HSV-2 neurovirulence in mice.     

Crystalline and molecular structure of the K+-complex of meso-valinomycin, cyclo(-(D-Val-L-Hyi-L-Val-D-Hyi)3-).KAuCl4

Crystal structure of the complex of meso-valinomycin with KAuCl4 (C60H102N6O18KAuCl4) was determined using direct X-ray diffraction analysis. The conformational state of the complex is similar to that determined earlier for free meso-valinomycin. Characteristic of it is the centrosymmetric bracelet shape stabilized by six intramolecular NH...OC hydrogen bonds of 4 --> 1 type. The K+ ion is located in an inner negatively charged octahedral cavity formed by six carbonyl oxygen atoms of ester groups. The observed differences in conformational angles of the complex and free are caused by readjustment of the geometry of the ion-binding cavity to the size of the ion bound during complexation.     

A Two-Dimensional Electron Gas as a Sensitive Detector for Time-Resolved Tunneling Measurements on Self-Assembled Quantum Dots

A two-dimensional electron gas (2DEG) situated nearby a single layer of self-assembled quantum dots (QDs) in an inverted high electron mobility transistor (HEMT) structure is used as a detector for time-resolved tunneling measurements. We demonstrate a strong influence of charged QDs on the conductance of the 2DEG which allows us to probe the tunneling dynamics between the 2DEG and the QDs time resolved. Measurements of hysteresis curves with different sweep times and real-time conductance measurements in combination with an boxcar-like evaluation method enables us to unambiguously identify the transients as tunneling events between the s- and p-electron QD states and the 2DEG and rule out defect-related transients.