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A larger external ear replica for use on a KEMAR manikin has been developed to meet the needs of hearing aid designers and other manikin users. The ear was selected from the 24 subject sample used by Burkhard and Sachs (1975) as the basis for the original ear development. Ear dimensions were chosen to be two standard deviations larger than the existing ear. A mirroring technique was used to give right and left ears with nearly identical properties. Responses of the manikin with the new ears are given and compared with responses with the original ears.  相似文献   
404.
This paper investigates the possibility of developing a fully micro realistic version of elementary quantum mechanics. I argue that it is highly desirable to develop such a version of quantum mechanics, and that the failure of all current versions and interpretations of quantum mechanics to constitute micro realistic theories is at the root of many of the interpretative problems associated with quantum mechanics, in particular the problem of measurement. I put forward a propensity micro realistic version of quantum mechanics, and suggest how it might be possible to discriminate, on experimental grounds, between this theory and other versions of quantum mechanics.  相似文献   
405.
We extend some results concerning the univalence of rational functions recently obtained by Mitrinovi相似文献   
406.
The 1-alkoxy-4-nitro-1,2,3-benzotriazole system was prepared using a phase transfer catalysis procedure. The physical and spectral properties of the system are reported. Molecular orbital calculations on the 1-methoxy derivative are used to explain the spectroscopic and electronic properties of the system.  相似文献   
407.
Abstract— –The lethal effect of a continuous spectrum of light at wavelengths longer than 300 nm has been examined for the yeast Rhodotorula glutinis. A survival curve consisting of a shoulder, an exponential phase of death, and a “tailing off” phase was shown to occur when cells were irradiated in the absence of a sensitizing dye. An action spectrum showed that the portion of the light used for irradiation which is lethal to the cells lies between 310 and 430 nm. It was found that carotenoid pigments were not able to provide any protection against this endogenously photosensitized oxidation. Exponentially growing cells were the most sensitive to killing and, as cells approached and entered into the stationary phase of growth, they became more resistant until a constant level of sensitivity was reached. A primary temperature effect on the length of the shoulder prior to the death of the cell has been observed. The sensitivity was greatest at low temperatures with an optimum resistance occurring at 22.5°C and an increasing sensitivity occurring at higher temperatures. Various sites have been examined for cellular damage which might lead to the death of the cell. Damage was found to impair the function of the plasma-lemma, the glycolytic and respiratory system, the nucleus, and to be observable cytologically.  相似文献   
408.
The reversible cyclic voltammetry of pea plastocyanin (Pisum sativum) was studied with a wide range of electrodes: edge-oriented pyrolytic graphite (PGE), glassy carbon (GCE), gold (Au) and platinum (Pt) electrodes. Plastocyanin was coated onto the electrode surface by exploiting the electrostatic interaction between the negatively charged protein and a wide range of positively charged promoters. The effect of the redox response with an extended range of promoters, including poly-L-lysine, polymyxin B, neomycin, tobramycin, geneticin, spermine and spermidine, were included in this study. The resulting cyclic voltammograms reveal that the observed midpoint potential for plastocyanin can be shifted significantly depending on the choice of promoter. The stability of the negatively charged plastocyanin-promoter layer on an electrode was gauged by the rate of bulk diffusion of the protein from the immobilised film into the solution. Reversible cyclic voltammograms were obtained using edge-oriented pyrolytic graphite (PGE) and glassy carbon electrodes (GCE) with all promoters; however, platinum and gold electrodes were unable to sustain a defined redox response. The combination of pyrolytic graphite electrode/poly-L-lysine/plastocyanin was found to be the most stable combination, with a redox response which remained well defined in solution for more than 1 h at pH 7.0. The midpoint potentials obtained in this manner differed between the two graphite electrodes PGE and GCE using poly-L-lysine as the promoter. This effect was in addition to the expected pH dependence of the midpoint potential for plastocyanin and the results indicated that the pK(a) for plastocyanin on PGE was 4.94 compared to that on GCE of 4.66. It is concluded that both the electrode material and the nature of the promoter can influence the position of the redox potentials for proteins measured in vitro. This study extends the range of biogenic promoters used in combination with electrode materials. Thus, we can begin to develop a more comprehensive understanding of electrode-protein interactions and draw conclusions as to metalloprotein function, in vivo. To support these studies, we have sought information as to the nature of the electrode/promoter/protein interaction using scanning tunneling microscopy (STM) to study both the promoter and the plastocyanin protein on a gold surface.  相似文献   
409.
Synthetic studies have shown that juncunol is 2-hydroxy-1,7-dimethyl-5-vinyl-9,10-dihydrophenanthrene 18, and not the 1,6-dimethyl-7-vinyl isomer 2 as originally assumed.  相似文献   
410.
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