INTERNAL FLOW IN CROSS-FLOW FAN FOR AIR CONDITIONER

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PET imaging of brain tumor with [methyl-11C]choline

This article describes a new method of [11C]choline synthesis for intravenous injection. We aimed at the utilization of this compound for brain tumor imaging with PET. METHODS: After [11C]carbon dioxide production in a cyclotron and the subsequent [11C]methyl iodide synthesis, [methyl-11C]choline was synthesized by the reaction of [11C]methyl iodide with "neat" dimethylaminoethanol at 120 degrees C for 5 min. Purification was achieved by evaporation of the reactants followed by passage of the aqueous solution of the product through a cation-exchange resin cartridge. The time required for overall chemical processing, excluding the cyclotron operation, was 15 min. Radiochemical yield was > 98%. Radiochemical purity was > 98%. Chemical purity was > 90% (dimethylaminoethanol was the only possible impurity). Specific radioactivity of the product was > 133 GBq/mumol. The whole body distribution was examined in rabbits with PET. Clinical studies were performed in patients with brain tumor using PET after intravenous injection of 370 MBq of [11C]choline. RESULTS: In rabbits,[11C]choline was taken up from blood by various tissues very rapidly, and the radioactivity remaining in blood became almost negligible 5 min after intravenous injection. Taking advantage of this characteristic, we obtained stable tissue distribution images of human brain using PET. In patients with brain tumor, PET produced clearly delineated positive images of the tumors. CONCLUSION: Carbon-11-choline can be used for obtaining clear images of brain tumor in PET.     

Surgical treatment of obstructive jaundice

Genetically engineered structural variants of human beta2-microglobulin (beta2m) were produced by sequence exchange with mouse beta2m for the purpose of examining species-specific antigenic determinant expression. For aggregate mapping, mouse and human beta2m, which differ by 30% in their primary sequence of 99 amino acids, were prepared as chimeric (human X mouse) molecules and expressed in the FO-1 beta2m-null human melanoma cell line. A chimera containing residues 1-69 from human beta2m (and residues 70-99 from mouse beta2m) induced expression of the epitopes defined by the anti-beta2m monoclonal antibodies (mAb) BBM.1, NAMB-1, and L368; the reverse chimera did not, although HLA class I heavy chain was evident on the cell surface as determined with the TP25.99 mAb. For fine dissection of the epitopes defined by these mAbs, site-directed mutants of beta2m were prepared by replacement of individual amino acids in human beta2m with the dimorphic residue from mouse beta2m. Substitutions were made at each divergent residue between positions 1 and 66 and, as controls for COOH-terminal modification, a series of residues between positions 75 and 94. Replacement of amino acids 38, 44, and 45, but not 16 other dimorphic residues in the linear stretch from residue 1 to residue 66, resulted in the loss of, or gross reduction in, binding by mAbs BBM.1 and NAMB-1. A reduction in binding was also observed for mAb L368. These data provide strong evidence that the antigenic epitopes defined by these mAb map to a region including S3 and its adjacent intra-beta-strand turn of the three-stranded beta-pleated sheet of beta2m. The mapping of these epitopes is consistent with their accessibility in the assembled major histocompatibility complex class I molecule and indicates that the region from amino acid 38 to 45 is an important structural feature in the "foreignness" of human and mouse beta2m.     

Minimum Cost Partitions of Trees with Supply and Demand

Let T be a given tree. Each vertex of T is either a supply vertex or a demand vertex, and is assigned a positive integer, called the supply or the demand. Every demand vertex v of T must be supplied an amount of ??power,?? equal to the demand of v, from exactly one supply vertex through edges in T. Each edge e of T has a direction, and is assigned a positive integer which represents the cost required to delete e from T or reverse the direction of e. Then one wishes to obtain subtrees of T by deleting edges or reversing the directions of edges so that (a)?each subtree contains exactly one supply vertex whose supply is no less than the sum of all demands in the subtree and (b)?every edge is directed away from the supply vertex in each subtree. One wishes to minimize the total cost to obtain such subtrees from T. In the paper, we first show that this minimization problem is NP-hard, and then give a pseudo-polynomial-time algorithm to solve the problem. We finally give a fully polynomial-time approximation scheme (FPTAS) for the problem.     

Effect of excess Li2S on electrochemical properties of amorphous li3ps4 films synthesized by pulsed laser deposition

Amorphous Li₃PS₄ films were synthesized by pulsed laser deposition (PLD) at room temperature using Li₃PS₄ targets with excess lithium and sulfur. Raman and X‐ray photoemission spectroscopies indicated that the Li₃PS₄ film synthesized with a stoichiometric amount of Li₃PS₄ target contained lithium‐deficient phases such as Li₄P₂S₆, Li_2?xS and sulfur due to composition deviation caused during the ablation process. The film synthesized with a 14% Li₂S‐excess target (Li_3.42PS_4.21) contained fewer impurities, and exhibited a higher ionic conductivity of 5.3 × 10^?4 S/cm at 298 K than the lithium‐deficient film (3.1 × 10^?4 S/cm). The target composition is an important factor for the fabrication of highly conductive Li₃PS₄ films for electrolytes in thin‐film batteries.     

Spring bloom in a hypereutrophic lake, Lake Kasumigaura, Japan—V : Factors controlling natural population of phytoplankters

Temperature was the limiting factor controlling the multiplication rate and standing stock of natural population density of phytoplankters in the lake of Tsuchiura Harbor during the spring bloom of 1980. The temperature relationship of the multiplication rate could be expressed as an Arrhenius equation during the spring bloom. The species composition of the natural phytoplankton community, on the other hand, was affected chiefly by combination of the ambient nutrient concentrations of ammonium, nitrate, phosphate and silicate. Although many phytoplankton species occurred, one temperature relationship appeared to hold for mixed species of the natural community from 4.4 to 24.9° C.     

Experimental decomposition of the positive bias temperature stress‐induced instability in self‐aligned coplanar InGaZnO thin‐film transistors and its modeling based on the multiple stretched‐exponential functions

Decomposition of the positive gate‐bias temperature stress (PBTS)‐induced instability into contributions of distinct mechanisms is experimentally demonstrated at several temperatures in top‐gate self‐aligned coplanar amorphous InGaZnO thin‐film transistors by combining the stress‐time‐divided measurements and the subgap density‐of‐states (DOS) extraction. It is found that the PBTS‐induced threshold voltage shift (ΔV_T) consists of three mechanisms: (1) increase of DOS due to excess oxygen in the active region; (2) shallow; and (3) deep charge trapping in the gate insulator components. Corresponding activation energy is 0.75, 0.4, and 0.9 eV, respectively. The increase of DOS is physically identified as the electron‐capture by peroxide. Proposed decomposition is validated by reproducing the PBTS time‐evolution of I–V characteristics through the technology computer‐aided design simulation into which the extracted DOS and charge trapping are incorporated. It is also found that the quantitative decomposition of PBTS‐induce ΔV_T accompanied with the multiple stretched‐exponential models enables an effective assessment of the complex degradation nature of multiple PBTS physical processes occurring simultaneously. Our results can be easily applied universally to any device with any stress conditions, along with guidelines for process optimization efforts toward ultimate PBTS stability.     

Particle swarm optimization with mutation operations controlled by landscape modality estimation using hill-valley detection

Particle swarm optimization (PSO) is one of swarm intelligence algorithms and has been used to solve various optimization problems. Since the performance of PSO is much affected by the algorithm parameters of PSO, studies on adaptive control of the parameters have been done. Adaptive PSO (APSO) is one of representative studies. Parameters are controlled according to the evolutionary state, where the state is estimated by distance relations among a best search point and other search points. Also, a global Gaussian mutation operation is introduced to escape from local optima. In this study, a new adaptive control based on landscape modality estimation using hill-valley detection is proposed. A proximity graph is created from search points, hills and valleys are detected in the graph, landscape modality of an objective function is identified as unimodal or multimodal. Parameters are adaptively controlled as: parameters for convergence are selected in unimodal landscape and parameters for divergence are selected in multimodal landscape. Also, two mutation operations are introduced according to the modality. In unimodal landscape, a new local mutation operation is applied to the worst hill point which will be moved toward the best point for convergence. In multimodal landscape, a new adaptive global mutation operation is applied to all hill points for escaping from local optima. The advantage of the proposed method is shown by comparing the results of the method with those by PSO with fixed parameters and APSO.