Materials balance in primary batteries. III. Computer aided design for standard size lithium — thionyl chloride high power cells

The study was continued of the design characteristics of high power type batteries made with the lithium/thionyl chloride system. A computer programme flow chart is presented for solving the system of equations correlating all the dimensions of cell components for any selected cell size. Various cell designs are presented for the three standard cell sizes, AA, C and D showing the effect of the geometry of the cell components on the resultant cell capacity. An optimized cell design is suggested for each particular discharge rate required. As a result of the optimization of the electrode structure, a substantial improvement in the maximum cell capacity was obtained with all three cell sizes.     

Materials balance in primary batteries. II. Lithium inorganic batteries at high discharge rates

A study was continued of the design characteristics and optimization procedures leading to an improvement of the maximum cell capacity obtainable with the high power type lithium inorganic batteries. The general relations derived for the low power type cells have been modified for use in the design of the high power type cells. A materials balance was established for the interior components of cylindrical cells made for high discharge rates.Design parameters were calculated using a computer program for several sizes of cylindrical cells. A satisfactory agreement was reached between the predicted and the realized performance of the cells built with the calculated design parameters.     

Effect of polytetrafluoroethylene covering of Palmaz stents on the development of intimal hyperplasia in human iliac arteries

PURPOSE: The occurrence of neointimal hyperplasia within a stent may result in restenosis with recurrent symptoms of end-organ ischemia. This study evaluated the potential of a nonporous covering of a stent to function as a barrier to the formation of intrastent neointimal hyperplasia. MATERIALS AND METHODS: Twelve endovascular stent grafts were used to treat 12 high-risk patients with limb-threatening ischemia secondary to long-segment iliac artery occlusion. A 6-mm, thin-walled polytetrafluoroethylene graft was inserted and anchored to the common iliac artery with use of Palmaz stents. Each stent was covered by graft material over one-half of its length. Control angiograms obtained immediately after graft insertion were compared with follow-up angiograms obtained between 4 and 6 months after the initial procedure. On each angiogram, the region of the stent was magnified by 20x to permit computerized luminal diameter measurements. RESULTS: The mean luminal diameter within the stent was significantly greater on the covered (7.7 mm +/- 0.33 standard deviation) compared with the uncovered (6.7 mm +/- 0.85 standard deviation) portions (P < .01). CONCLUSIONS: Partially covered stents are a unique model for assessing the effects of an extrinsic stent covering on arterial healing and myointimal hyperplasia. These data suggest that a relatively nonporous covering of polytetrafluoroethylene may inhibit stent-related restenosis in iliac arteries.     

Sputtering of adsorbed layers by ion bombardment

Sputtering of adsorbed species by particle bombardment is a major source of contamination in present-day thermonuclear devices. Nevertheless, there have been very few systematic studies of the sputtering processes which produce this contamination. These questions were investigated, both experimentally and numerically, for systems with various projectile and target mass ratios. We studied the sputtering of S and O from Ni (111) and Ni (110) surfaces by Ar⁺, Ne⁺ and He⁺ ions between 100 and 1600 eV. The sputtering cross-sections increase with ion mass and energy from 10^?16 to 10^?14 cm² for S in the observed range of parameters and are lower for oxygen. There is a maximum for an impact angle of about 30° relative to the surface. These results are generally confirmed by numerical studies with a modification of the computer program MARLOWE. Also the influence of various parameters, such as surface binding energy, surface geometry, impact angle, etc. will be discussed. The theoretical estimates of Winters and Sigmund are applied to the system under investigation. These calculations yield the right order of magnitude for the sputtering cross-sections. According to these results the main contributions to sputtering are from direct knock-off effects and from backscattered primaries, with a smaller contribution arising from the sputtering of the base material.     

A carbohydrate-rich diet reduces LDL size in QQ homozygotes for the Gln192Arg polymorphism of the paraoxonase 1 gene

Paraoxonase 1 (PON 1) is an esterase with antioxidant properties that is present in HDL. Gln192Arg polymorphism (also named Q192R or Q/R) of the PON 1 gene that encodes this protein defines two alleles (Q and R). The R allele has been associated with higher cardiovascular risk. LDL size and susceptibility to oxidation also have been identified as cardiovascular risk factors. Our objective was to determine whether genetic variations in the Gln192Arg polymorphism influence LDL size and susceptibility to oxidation after the consumption of diets with different fat content. In our experiments, the participants (n=98), underwent three 4-wk diets—one, saturated fat-enriched (SAT); another, monounsaturated fat-enriched (MONO); and a third, carbohydrate-enriched (CHO). We observed that LDL were smaller in the QQ group after the CHO diet vs. the SAT (P<0.01) and MONO diets (P<0.03). No differences in LDL size were found in QR/RR subjects. When we analyzed lag time of oxidation of LDL, we found that when carriers of the R allele (QR/RR) received the MONO diet, the lag period of LDL oxidation was longer as compared with the CHO diet. Otherwise, we found no differences in QQ homozygotes when we evaluated the lag time of oxidation of LDL after the three diets. These results suggest that the Gln192Arg polymorphism of the paraoxonase gene influences LDL size and susceptibility to oxidation in response to diet.     

On the spuriousness of the symbolic/subsymbolic distinction

The article criticises the attempt to establish connectionism as an alternative theory of human cognitive architecture through the introduction of thesymbolic/subsymbolic distinction (Smolensky, 1988). The reasons for the introduction of this distinction are discussed and found to be unconvincing. It is shown that thebrittleness problem has been solved for a large class ofsymbolic learning systems, e.g. the class oftop-down induction of decision-trees (TDIDT) learning systems. Also, the process of articulating expert knowledge in rules seems quite practical for many important domains, including common sense knowledge.The article discusses several experimental comparisons betweenTDIDT systems and artificial neural networks using the error backpropagation algorithm (ANNs usingBP). The properties of one of theTDIDT systemsID3 (Quinlan, 1986a) are examined in detail. It is argued that the differences in performance betweenANNs usingBP andTDIDT systems reflect slightly different inductive biases but are not systematic; these differences do not support the view that symbolic and subsymbolic systems are fundamentally incompatible. It is concluded, that thesymbolic/subsymbolic distinction is spurious. It cannot establish connectionism as an alternative cognitive architecture.