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1.
Christiana Payne 《Annals of science》2013,70(4):373-375
Classic voltaic batteries of the silver/zinc and copper/zinc types are the ancestors of today's primary cells, and facilitated the development of many aspects of electrical technology. Nevertheless, they appear never to have been studied and evaluated in a quantitative manner, with results recorded in terms of volts, amps, ohms, and watts. Research of this nature is reported here, and has been conducted for the most part with copper/zinc cells. Log–log graphs of voltage versus load and current, and power versus load, are presented for many electrolyte systems. It has been shown that, although the textbook electrolyte of dilute sulphuric acid does work, it is an order of magnitude inferior to a solution containing some additional nitric acid. The latter diminishes the current‐limiting phenomenon of polarization, and was in fact used by Davy, Faraday, and other early investigators. A quantitative consideration of Nicholson and Carlisle's discovery of the electrolysis of water with a silver/zinc voltaic pile is followed by examination of the electrolysis of pure water, trough batteries, and Davy's isolation of potassium and sodium. Every battery gives maximum power when its resistance is adjusted (by appropriate series/parallel connections) to match the resistance of the load: the maximum output of the ‘Great Battery’ of the Royal Institution is assessed at no more than 3 kW. The paper concludes with a note on the recognized hazard of long‐term exposure to mercury vapour (produced by amalgamation of zinc electrodes in batteries) and its possible relevance to the health of Michael Faraday. 相似文献
2.
Individual recognition in mice mediated by major urinary proteins. 总被引:25,自引:0,他引:25
J L Hurst C E Payne C M Nevison A D Marie R E Humphries D H Robertson A Cavaggioni R J Beynon 《Nature》2001,414(6864):631-634
The ability to recognize individuals is essential to many aspects of social behaviour, such as the maintenance of stable social groups, parent-offspring or mate recognition, inbreeding avoidance and the modulation of competitive relationships. Odours are a primary mediator of individuality signals among many mammals. One source of odour complexity in rodents, and possibly in humans, resides in the highly polymorphic major histocompatibility complex (MHC). The olfactory acuity of mice and rats allows them to distinguish between the urinary odours of congenic strains differing only in single genes within the MHC, although the chemical mediators or odorants are unknown. However, rodent urine also contains a class of proteins, termed major urinary proteins (MUPs), that bind and release small volatile pheromones. We have shown that the combinatorial diversity of expression of MUPs among wild mice might be as great as for MHC, and at protein concentrations a million times higher. Here we show in wild house mice (Mus domesticus) that urinary MUPs play an important role in the individual recognition mechanism. 相似文献
3.
A I den Hollander J B ten Brink Y J de Kok S van Soest L I van den Born M A van Driel D J van de Pol A M Payne S S Bhattacharya U Kellner C B Hoyng A Westerveld H G Brunner E M Bleeker-Wagemakers A F Deutman J R Heckenlively F P Cremers A A Bergen 《Nature genetics》1999,23(2):217-221
Retinitis pigmentosa (RP) comprises a clinically and genetically heterogeneous group of diseases that afflicts approximately 1.5 million people worldwide. Affected individuals suffer from a progressive degeneration of the photoreceptors, eventually resulting in severe visual impairment. To isolate candidate genes for chorioretinal diseases, we cloned cDNAs specifically or preferentially expressed in the human retina and the retinal pigment epithelium (RPE) through a novel suppression subtractive hybridization (SSH) method. One of these cDNAs (RET3C11) mapped to chromosome 1q31-q32.1, a region harbouring a gene involved in a severe form of autosomal recessive RP characterized by a typical preservation of the para-arteriolar RPE (RP12; ref. 3). The full-length cDNA encodes an extracellular protein with 19 EGF-like domains, 3 laminin A G-like domains and a C-type lectin domain. This protein is homologous to the Drosophila melanogaster protein crumbs (CRB), and denoted CRB1 (crumbs homologue 1). In ten unrelated RP patients with preserved para-arteriolar RPE, we identified a homozygous AluY insertion disrupting the ORF, five homozygous missense mutations and four compound heterozygous mutations in CRB1. The similarity to CRB suggests a role for CRB1 in cell-cell interaction and possibly in the maintenance of cell polarity in the retina. The distinct RPE abnormalities observed in RP12 patients suggest that CRB1 mutations trigger a novel mechanism of photoreceptor degeneration. 相似文献
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J C Chabala V B Waits T Ikeler A A Patchett L Payne L H Peterson R A Reamer K Hoogsteen M Wyvratt W L Hanson 《Experientia》1991,47(1):51-53
1-(Substituted)benzyl-5-aminoimidazole-4-carboxamides are potent orally active inhibitors of Trypanosoma cruzi infections in mice. The most active compounds are the 1-(4-chlorobenzyl)- and 1-(3,4-dichlorobenzyl)-analogs (L-153,094 [2] and L-153,153 [4], resp.) which are approximately 7-fold more potent upon oral administration than nifurtimox (Lampit) in suppressing parasite levels in the blood of mice with acute Trypanosoma cruzi infections. 相似文献
6.
T lymphoblastoid cell lines from Marek's disease lymphomas 总被引:18,自引:0,他引:18
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Summary A fast simple method for assay of total blood lipids has been devised by precipitating blood proteins with methanol and extracting lipids into diethyl ether. The change in refractive index of the methanol-ether due to dissolved lipids is measured in a refractometer. 相似文献
10.
A central question concerning vision is the identity of the biochemical pathway that underlies phototransduction. The large size of the ventral photoreceptors of Limulus polyphemus renders them a favourite preparation for investigating this problem. The fact that a single photon opens approximately 1,000 ionic channels in these photoreceptors suggests the need for an internal transmitter. We have investigated whether inositol 1,4,5-trisphosphate (InsP3) functions as such an internal transmitter, given that InsP3 may act as an intracellular messenger in other cellular processes. Here we report that in Limulus, intracellular pressure injection of InsP3 both excites and adapts ventral photoreceptors in a manner similar to light. 相似文献