Glow discharge polymerization in the CF3Br/CH4 system

Summary Glow discharge polymerization in the system of the CF₃Br/CH₄ mixture was investigated by infrared spectroscopy and ESCA.Surface energies of polymers from the CF₃Br/CH₄ mixture decrease as increasing the concentration of CF₃Br in the mixture, but the value of surface energy is not as low as that of polymers from CF₄/CH₄ mixture and from CF₂=CF₂. Polymers from the CF₃Br/CH₄ mixture possess a large amount of bromine as well as fluorine, and consist of five structural features which was determined by deconvolution of the C_ls level spectra. A relative concentration of each structural feature was also discussed in comparison with that for polymers from the CF₄/CH₄ mixture and CF₂=CF₂.     

Inhibition of interleukin-6-induced human immunodeficiency virus type 1 expression by anti-gp130 monoclonal antibody

Interleukin 6 (IL-6) has been reported to upregulate the expression of human immunodeficiency virus type 1 (HIV-1) in infected monocyte/macrophages. Since IL-6 signal is transduced through the membrane glycoprotein gp130, we investigated the inhibitory effect of anti-gp130 monoclonal antibody (mAb) on IL-6-induced viral expression in monocytic cell lines latently infected with HIV-1. IL-6 significantly induced the expression of HIV-1 in U1 cells, whereas it had no effect in OM-10.1 cells. Flow cytometric analysis revealed that U1 but not OM-10.1 cells expressed gp130 on their surface. The anti-gp130 mAb could inhibit IL-6-induced HIV-1 expression in U1 cells in a dose dependent fashion. These results suggest that blocking the gp130 signal transduction may have therapeutic potential for the treatment of HIV-1 infection.     

Studies on the thermal degradation of phosphorus containing polymers: 7. Thermal degradation of phosphorylated poly(vinyl alcohol)

The thermal degradation of phosphorylated poly(vinyl alcohol) was investigated using thermogravimetric analysis, infra-red spectroscopy and gas chromatography. The introduction of phosphoric acid groups changed the course of the thermal degradation of the polymer. The dehydration was accelerated and the scission of the polymer chain was inhibited. The cis-β-elimination mechanism of the phosphorus ester group was proposed for the accelerated dehydration.     

Inverse microemulsion polymerization of acrylamide in the presence of N,N-dimethylacrylamide

The presence of N,N-dimethylacrylamide (NDA) influences the stability of initial, clear, single-phase Winsor IV inverse microemulsion composed of toluene/AOT (sodium salt of bis(2-ethylhexyl) sulfosuccinate)/NDA/water/acrylamide (AAm). For a molar fraction of NDA, n_NDA = [NDA]/([NDA] + [AAm]) = 0.200 a single-phase system turned to a milky one during polymerization initiated by oil-soluble dibenzoyl peroxide or water-soluble ammonium peroxodisulfate, and finally a two-phase system was formed. For n_NDA values greater than 0.200 also the precipitation of a polymeric product was observed during polymerization. The (co)polymerization rate of AAm and NDA exponentially decreases with increasing value of n_NDA, while the reverse is true for the (co)polymer particle diameter. The results support the idea of simultaneously proceeding free-radical polymerization initiated by free radicals in continuous oil and dispersed water phase of the inverse microemulsion system.     

行人导致侧力的试验研究

根据对几座斜拉索人行天桥的观测发现，当大量行人通过天桥时，可在桥支架上引起频率大约为1．0Hz的侧向振动。行人的曲线运动会导致侧向动力，从而引起桥支架的振动。一旦大桥开始振动，一些行人便开始与支架共振，从而进一步增加了支架反应。试验主要为寻找行人在振动桥面上所产生的动态力。行人走在振动台上专门设计的钢板上，振动台有着不同的频率和振幅。     

Formation of ST Plasmas by ECH on LATE

Experiments on formation of spherical tokamak (ST) plasmas by electron cyclotron heating (ECH) alone without a central OH solenoid have been carried out on LATE (Low Aspect ratio Torus Experiments). By injecting a 2.45 GHz microwave pulse of 6.3 kW for 4 seconds, a plasma current is initiated and ramped up to IP ≌ 3 kA, and finally maintained for l second by adjusting the external vertical field. Magnetic measurements show that closed flux surfaces are formed and the last closed flux surface has an aspect ratio of A - 1.3 and an elongation of K - 1.3. The electron density measured by an interferometer is more than 1.5 × 1011 cm-3 which exceeds twice of the plasma cut-off density, suggesting that electron cyclotron heating by mode-converted electron Bernstein waves may take place.     

Flame-retardant effect of tris(2,3-dibromopropyl) phosphate on polystyrene

The flame-retardant effect of tris(2,3-dibromopropyl) phosphate (TBPP) on polystyrene was investigated using thermogravimetry, infrared spectroscopy, gel permeation chromatography, and electron spectroscopy for chemical analysis (ESCA). The following results and conclusions were obtained: (1) The addition of TBPP (about 3 wt%) to polystyrene had flame-retardant properties. (2) The addition of TBPP resulted in lowering the temperature of the burning surface and the amount of volatile products. TBPP increased the thermal stability of polystyrene. (3) TBPP inhibited oxidative attack on polystyrene. In the presence of TBPP the formation of peroxide groups at the burning surface was inhibited. It is inferred that this inhibition decreases the evolution of flammable fuels from the burning surface and contributes flame-retardant properties. There is a lesser possibility that TBPP acts as a physical barrier that limits oxygen access. At present there is no idea of why TBPP inhibits thermoxidative reactions of polystyrene.     

Altered responding to cholecystokinins and dopaminergic agonists following 6-hydroxydopamine treatment in rats.

In 5 experiments with 265 male Wistar albino rats, production of lesions in the brain dopamine (DA) system by intraventricular injection of 6-hydroxydopamine (6-OHDA) resulted in increased responses to subcutaneous apomorphine (0.5 mg/kg) and reduced responses to methamphetamine (0.15 mg/kg). It also made Ss increase responding to intracerebroventricular (icv) cholecystokinin octapeptide (CCK-8; 0.5–2 μg) and reduce responding to cholecystokinin tetrapeptide (CCK-4; 0.5–2 μg). Response changes were quantified by measuring the level of general activity. Results indicate that DA dysfunction not only affected DA receptor sensitivity but also the sensitivity of the CCK system. The response to CCK-8 was partially blocked by a selective CCK-8 antagonist, proglumide (5 μg, icv), a result suggesting the involvement of the CCK-8 receptor system. Results indicate that manipulation of 1 neuronal system could induce sensitivity changes in another closely related system. (32 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Preparation of partly hydrophobized,crosslinked polyacrylamide particles by terpolymerization of acrylamide/ N,N‐methylenebisacrylamide/styrene in inverse microemulsion

Free‐radical polymerization of a termonomer system comprising acrylamide (AAm) N,N ′‐methylenebisacrylamide (MBAAm) and styrene (S) initiated by water‐soluble ammonium peroxodisulphate (APS) or by toluene‐soluble dibenzoyl peroxide (DBP) in inverse microemulsion (toluene/S/AOT//water//AAm/MBAAm), leads to the formation of partly hydrophobized crosslinked polymer particles of tailored chemical composition, degree of crosslinking and polymer particle size. Styrene strongly decreases the rate of terpolymerization, while the presence of MBAAm has almost no effect on the polymerization rates observed. This conclusion is valid for both APS and DBP initiators. Increase of the S/T mass ratio (T is toluene) in inverse microemulsion leads to an increase of polymer particle diameter from about 20 nm to about 50 nm attributed to toluene swelling of the styrene‐rich structural moieties of AAm‐co‐S copolymer located on the surface of polymer particles. Polymerization kinetics measurements pointed to the important role of exiting water soluble AAm and MBAAm monomer radicals generated by thermal decomposition of APS in water pools of inverse micelles for initiation of polymerization reactions of sparingly water‐soluble S monomer in the oil‐phase of the inverse microemulsion. It was shown that the polymerization and copolymerization reactions of S in the presence of AAm and/or MBAAm are effectively initiated by water‐soluble APS and also by oil‐soluble DBP initiators. During dialysis the polymerized single‐phase water/oil Winsor IV inverse microemulsion gradually converts itself into a two‐phase oil/water Winsor I dispersion system with volume fraction of aqueous phase Φ_aw ≈ 0.950. The water phase contains water swelled, crosslinked polymer particles of diameters 80–300 nm. During dialysis, toluene and the sodium salt of bis(2‐ethyl hexyl)sulphosuccinic acid (AOT) partition between the oil phase of the dialysed dispersion system and the water dialysate. After evaporation of water from the dialysed inverse microemulsion, solid, dried, crosslinked polymer particles in the form of a transparent film, almost uncontaminated by AOT surfactant, were obtained. © 2000 Society of Chemical Industry