Catalytic action of metallic salts in autoxidation and polymerization: 11. Polymerization of methacrylic acid esters with sodium hexanitrocobaltate in methanol-water

The polymerization of a series of methacrylic acid esters (methyl, ethyl, isopropyl and n-butyl) with sodium hexanitrocobaltate, Na₃[Co(NO₂)₆] was carried out in a methanol-water mixed solvent. The homogeneity of the polymerization system was dependent on the composition of the mixed solvent and greatly affected the rate of the polymerization. A maximum rate was obtained at approximately equimolar fractions of methanol and water in the polymerization of methyl methacrylate. The effect of bulkiness of ester groups on the polymerizability of each monomer was indistinguishable in the mixed solvent system. Kinetic study of the polymerization of methyl methacrylate in a mixed solvent of about an equimolar fraction of methanol and water gave the following polymerization equation: $\text{R}{}_{\mathrm{p}}\text{= k[l]}{}^{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{[}\text{M}\text{]}{}^2$, and an apparent activation energy of 10.6 kcal/mol. The copolymerization of methyl methacrylate and styrene with the initiator suggested that polymerization proceeded via a radical mechanism. The possibility of a certain interaction between initiator, solvent and monomer in the initial stage of the polymerization is discussed on the basis of the kinetic data, properties of oligomers of methyl methacrylate, spectroscopic and other data.     

Studies on the ability of cellulosic materials to initiate graft copolymerization

The activity to initiate graft copolymerization was investigated for various cellulose samples. Oxidation of the sample with hydrogen peroxide or sodium hypochlorite indicated a remarkable increase in the per cent grafting as well as the number of grafts. This phenomenon must be attributed to the formation of special reactive groups in cellulosic materials. However, the treatment with hot water caused a definite decrease in the per cent grafting or the number of grafts for the graft copolymerization on the sample, indicating a lower activity to initiate graft copolymerization. Accordingly, the reactive groups, once formed on the sample by oxidation, seemed to be easily decomposed by hot water. The ferric ion adsorbed on cellulose increased the per cent grafting and accelerated the formation of grafts, and the contribution of metallic ions to the initiation was recognized as one of the important factors of graft copolymerization.     

Low loss high-density optical cable with nylon-extruded fibre units

A low loss, highly dense cable containing nylon-extruded six-fibre units was examined. Suitable unit parameters were determined by measuring loss increases with lateral force and at low temperature. 216-fibre cable was manufactured using the nylon-extruded units, and cabling loss increase was found to be only 0.1 dB/km.     

Acquisition of sex-typed preferences in preschool-aged children.

Assessed a total of 119 preschool children with the Sex Role Learning Index (SERLI), a picture-choice instrument designed to compare children's preferences to both sex role stereotypes and each child's conception of what is sex appropriate. Boys showed higher masculine preferences in the section depicting child figures than in the section depicting adult figures, while girls showed more feminine preferences in the adult figures than child figures section. Boys were more masculine in their preferences than girls were feminine in the child figures section, but not in the adult figures section. Girls were also found to adhere more to their own conceptions of what is sex appropriate than to sex role stereotypes in the child figures section. Boy's scores in the adult figures section correlated significantly with MA and IQ, while girls' scores in the child figures section correlated with CA. Boys' scores on the SERLI were significantly correlated with scores on the It Scale for Children, but girls' scores were not. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Photoluminescence studies on InGaAlP layers grown by low-pressure metalorganic chemical vapor deposition

The optical properties for In_0.5(Ga_1-x Al _x )_0.5P (0 <x < 0.4) layers, grown by low-pressure Metalorganic Chemical Vapor Deposition, have been studied with photolominescence (PL) measurement. The PL intensity decreases with the increase of the Al composition (0 <x < 0.4). This dependence could not be accounted for only by the electron overflow from theΓ band to the X band. And the PL intensity is directly proportional to the excitation power at low temperature, below 50 K. On the other hand, the PL intensity is proportional to the second power of the excitation power at a high temperature range (>200 K). These results indicate that non-radiative recombination centers bound to theΓ band in In_0.5(Ga_1-x Al _x )_0.5P play a very important role in the radiation mechanism. PL dependence also shows these non-radiative recombination centers are thought to have strong relation to the aluminum substitution for In_0.5(Ga_1-x Al _x )_0.5P.     

Using artificial intelligence in communication system design

The authors describe a knowledge-based design support system, called KDSS, that will help designers inexperienced in communication system design easily create advanced systems like intelligent networks, and large-scale distributed computing systems. They began by designing a support system for protocol and communication software. They then experimented with applying expert-system technology in design support systems and developed an expert system for protocol synthesis called KSPS. An expert system for protocol and communication software design that is based on the earlier work is also part of KDSS     

Relationships among tenascin expression, DNA ploidy patterns, and multidrug resistance gene product (P-glycoprotein) in human colon carcinoma

Relationships among tenascin expression, DNA ploidy, and P-glycoprotein were examined in 81 primary human colon cancers and 61 metastatic lymph nodes. First, the DNA ploidy patterns of colon cancerous tissue surrounded (TN+) and not surrounded (TN-) by tenascin immunoreactivity were investigated. Then the expression of P-glycoprotein, one of two multidrug resistance gene products, was examined in TN+ and TN- colon cancer tissues by immunohistochemistry. Aneuploid DNA patterns were observed at high frequency in TN- colon cancer tissues (37/61) and metastatic lymph nodes (44/52). In contrast, diploid DNA patterns were observed predominantly in TN+ colon cancer tissues (50/56). Although P-glycoprotein expression was observed in primary TN+ and TN- colon cancer (9/81), the level of P-glycoprotein expression was not correlated with DNA aneuploidy in TN- colon cancer tissues. Overall, reduced tenascin expression was correlated well with DNA aneuploidy, but no significant correlation was found between DNA aneuploidy and P-glycoprotein appearing when cancer cells become resistant to several anti-cancer drugs. Thus, tenascin may play an important role in preventing colon cancer cells from invading surrounding tissues.     

A new lateral MOS-gated thyristor with controlling base-current

A new lateral MOS-gated thyristor, called the Base-Current-Controlled Thyristor, is described. This device is designed so that most holes at the on-stage reach the P base through the floating P⁺ region adjacent to the P base and the on-state MOSFET. At the turn-off stage, the interruption of the hole current to the P base due to switching off the above MOSFET occurs simultaneously with the conventional turn-off operation. The concept of this device is verified experimentally by using the fabricated lateral device with the external MOSFET. This device exhibits a better trade-off relation between the on-state voltage and the turn-off time compared uith the conventional MOS-gated thyristor