Scattering and absorption by thin metal wires in rectangularwaveguide-FDTD simulation and physical experiments

The high-frequency internal impedance model of a round ohmic conductor is incorporated into the subcell thin-wire formulation of the finite-difference time-domain method to model the microwave properties of metal wires. For magnetic metals, such as steel, an effective conductivity is introduced to account for the increase in ohmic loss due to the high-frequency permeability. Physical experiments with half-wave resonant copper- and steel-wire inclusions, supported by a dielectric slab in a standard S-band rectangular waveguide, support the formulation     

Clinical study in epidural injection with lappaconitine compound for post-operative analgesia

In this study, the effect and side-effect of epidural injection with lappaconitine compound for post-operative analgesia was observed. One hundred and twenty patients were randomly divided into 4 groups. Lappaconitine compound (LB) consisted of 12 mg of lappaconitine and 22.5 mg of bupivacaine, was given to group A (the group of observation), and lappaconitine 12 mg, bupivacaine 22.5 mg and morphine 2 mg to group B, C and D respectively for control. All were given by epidural injection with single blind method during post-operative pain of incision operation. Result showed that the initiating of analgesia was quicker in group A and C than that in group B and D, and the efficacy was group D > A > C > B. There was significant difference between group A and B in the above two parameters, P < 0.01 and P < 0.05. The analgisia maintenence time of single injection was D > A > B > C, that of group D was significantly longer than that of group A (P < 0.01). It indicated that the epidural injection with LB was more rapid and potent than that with lappaconitine alone in post-operative analgesia, and the former had no side-effect, it was safer than morphine.     

Predicting postlaryngectomy voice outcome in an era of primary tracheoesophageal fistulization: a retrospective evaluation

The aim of this study was to investigate the effect of the absence of elongate spermatids (ES) from the rat seminiferous epithelium on the quantitative secretion and synthesis of the three major Sertoli cell secretory proteins--SGP-1, SGP-2 and CP-2. Seminiferous tubules (ST) were isolated (a) from normal 28-day-old rats, in which the most mature germ cell type is the round spermatid, (b) from normal adult rats at stages IX-XIV of the spermatogenic cycle, i.e. after spermiation, or at stages I-V and VI-VIII, when ES are still attached to the Sertoli cell, and (c) at stages VI-VIII from normal adult rats and from rats treated with methoxyacetic acid (MAA) in order to specifically deplete ES at these stages. Two-dimensional SDS PAGE combined with computerized image analysis was used to analyse 35S-methionine-labelled intracellular and secreted proteins. In the case of SGP-1 and SGP-2, almost all of the protein synthesized by ST was secreted. The total amount of both SGP-1 and CP-2 secreted by unstaged ST from immature rats was significantly lower than that secreted by unstaged ST from adult rats. The total amount of SGP-1 and CP-2 secreted by adult ST at stages IX-XIV of the spermatogenic cycle also declined dramatically compared to ST at earlier stages. The proportion of the total CP-2 synthesized by ST which was secreted also declined in all situations in which ES were absent from the seminiferous epithelium. The synthesis of only SGP-2 was changed by ES depletion from ST at stages VI-VIII, which was almost doubled compared to synthesis of this protein by ST from control rats. Our results suggest strongly that the secretion of SGP-1 and SGP-2 is via the constitutive pathway, and that regulation of these two proteins by ES is at the level of protein synthesis. In contrast, the regulation of CP-2 by ES is predominantly at the level of secretion, suggesting that this protein is secreted via a regulated pathway. Our findings add to the evidence showing that ES play a major role in the regulation of Sertoli cell function.     

A linkage map of human chromosome 21:43 PCR markers at average intervals of 2.5 cM

A genetic linkage map of human chromosome 21q (HC21q) containing 43 markers genotyped by the polymerase chain reaction in the CEPH pedigrees is presented. The markers placed on this map are highly polymorphic with an average heterozygosity of 61%. The average interval size of the markers localized at 1000:1 odds is 2.5 cM. The map has a total length of 65.5 cM, with male and female lengths of 47.7 and 83.3 cM, respectively. The genotypes used in the construction of this map were subjected to rigorous error checking, which is reflected in the shorter map length compared to previous maps; the estimated error rate in genotyping is less than 0.04%. As noted in previous linkage maps there is increased recombination in females on proximal HC 21q and in the male in a region near the telomere. This map of HC 21 represents a highly informative and dense meiotic linkage map and will be useful in linking disease phenotypes to loci on this chromosome.     

ATMOSPHERIC DEPOSITION OF CHEMICAL SPECIES TO POLAR SNOW

Particles and gases can deposit from the atmosphere to polar snow by several mechanisms. Dry deposition can be considered to consist of three steps: aerodynamic transport from the free atmosphere to the viscous sublayer near the surface, boundary layer transport across the sublayer, and interactions with the surface. The particle dry deposition mass flux is dominated by the largest particles present in a size distribution. Wet deposition includes in-cloud and below-cloud scavenging, where the former refers to uptake of particles during nucleation of cloudwater as well as scavenging of particles and gases by existing droplets and ice crystals. Of all the wet deposition mechanisms, nucleation scavenging is often the most important mechanism for particles in the polar regions. Finally, incorporation of particles and gases into fog droplets and subsequent settling of the fog to the snow surface can be an important removal process in regions of frequent fog. For Summit, Greenland, the total deposition of MSA, SO₄^2-, Na⁺, K⁺, and Ca²⁺ during May 24-July 13, 1993 was dominated by wet deposition: this mechanism accounted for an average of 62% of the total deposition for these species. Fog and dry deposition accounted for 21% and 17% of the total, respectively. These results suggest that all three mechanisms may need to be considered when estimating total deposition of certain chemical species to polar snow.     

Integrated carbon nanotube field emission differential amplifier: Modeling and measurement of the common-mode rejection ratio

A novel integrated vacuum field emission (VFE) differential amplifier (diff-amp) utilizing carbon nanotube (CNT) emitters has been developed. A dual-mask microfabrication process was employed to achieve a VFE diff-amp by integrating identical CNT VFE transistors with built-in split gates and integrated anodes. The identical pair of triode amplifiers was well-matched in their device characteristics. The measured ac small-signal characteristics of the diff-amp showed a common-mode-rejection ratio (CMRR) of ~ 320 (~ 50 dB). The proposed analytical model of the CMRR was verified to be in good agreement with the experimental data. The successful implementation of the CNT diff-amp demonstrates a new way to achieve temperature and radiation tolerant VFE integrated microelectronics.