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排序方式: 共有305条查询结果,搜索用时 609 毫秒
21.
Peter D. Constable BSc Phd Robert N. Streeter Gerard J. Koenig Nigel R. Perkins Hani M. Gohar Dawn E. Morin 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》1997,11(2):71-79
The objectives of this study were to investigate the determinants of the anion gap (AG) in cattle and to evaluate the utility of AG in detecting hyperlactatemia in sick neonatal calves and adult cattle. The AG was calculated as AG = ([Na+] + [K+]) - ([Cl-] + [HCO3]), with all values in mEq/L. The AG of healthy neonatal calves (n = 16) was 29.6 ± 6.2 mEq/L (mean ± SD), and the blood L-lactate concentration ranged from 0.5 to 1.2 mM/L. The AG was significantly (P > .05) correlated with serum phosphate (r = .66) and creatinine (r = .51) concentrations. The AG of neonatal calves with experimentally induced diarrhea (n = 16) was 28.6 ± 5.6 mEq/L, and the blood L-lactate concentration ranged from 1.1 to 2.9 mM/L. The AG was significantly correlated with blood L-lactate concentration (r = .67), serum phosphate concentration (r = .63), creatinine concentration (r = .76), and blood pH (r = -.61). The AG of adult cattle with abomasal volvulus (n = 41) was 20.5 ± 7.8 mEq/L, and the blood L-lactate concentration ranged from 0.6 to 15.6 mM/L. The AG was significantly correlated with blood L-lactate concentration (r = .60), serum phosphate concentration (r = .71), creatinine concentration (r = .65), albumin concentration (r = .47), total protein concentration (r = .54), blood pyruvate concentration (r = .67), and blood pH (r = -.41) but not plasma β-OH butyrate concentration. The results indicate that the AG in cattle is only moderately correlated with blood L-lactate concentration and is similarly correlated with serum phosphate and creatinine concentrations in neonatal calves and adult cattle, as well as with serum albumin and total protein concentrations in adult cattle. Anion gap determination is of limited usefulness in predicting blood L-lactate concentration in sick cattle, whereas the correlation between AG and serum creatinine concentration in sick cattle suggests that an increased AG should alert the clinician to the potential presence of uremic anions. 相似文献
22.
23.
Analysis of xanthophylls in corn by HPLC 总被引:4,自引:0,他引:4
Moros EE Darnoko D Cheryan M Perkins EG Jerrell J 《Journal of agricultural and food chemistry》2002,50(21):5787-5790
An HPLC method was developed using the C-30 carotenoid column to separate and identify the major xanthophylls in corn (lutein, zeaxanthin, and beta-cryptoxanthin). A photodiode array detector and a mobile phase consisting of methyl tert-butyl ether/methanol/water was used. All three xanthophylls eluted in less than 25 min. Yellow dent corn had a total xanthophyll content of 21.97 microg/g with lutein content of 15.7 microg/g, zeaxanthin content of 5.7 microg/g, and beta-cryptoxanthin of 0.57 microg/g. Commercial corn gluten meal had a 7 times higher concentration of xanthophylls (145 microg/g), and deoiled corn contained 18 microg/g, indicating that the xanthophylls are probably bound to the zein fraction of corn proteins. 相似文献
24.
Perkins PB 《Science (New York, N.Y.)》1917,45(1153):121-124
25.
Coleman JN Lotya M O'Neill A Bergin SD King PJ Khan U Young K Gaucher A De S Smith RJ Shvets IV Arora SK Stanton G Kim HY Lee K Kim GT Duesberg GS Hallam T Boland JJ Wang JJ Donegan JF Grunlan JC Moriarty G Shmeliov A Nicholls RJ Perkins JM Grieveson EM Theuwissen K McComb DW Nellist PD Nicolosi V 《Science (New York, N.Y.)》2011,331(6017):568-571
If they could be easily exfoliated, layered materials would become a diverse source of two-dimensional crystals whose properties would be useful in applications ranging from electronics to energy storage. We show that layered compounds such as MoS(2), WS(2), MoSe(2), MoTe(2), TaSe(2), NbSe(2), NiTe(2), BN, and Bi(2)Te(3) can be efficiently dispersed in common solvents and can be deposited as individual flakes or formed into films. Electron microscopy strongly suggests that the material is exfoliated into individual layers. By blending this material with suspensions of other nanomaterials or polymer solutions, we can prepare hybrid dispersions or composites, which can be cast into films. We show that WS(2) and MoS(2) effectively reinforce polymers, whereas WS(2)/carbon nanotube hybrid films have high conductivity, leading to promising thermoelectric properties. 相似文献
26.
Isolation of the gene for a glycophorin-binding protein implicated in erythrocyte invasion by a malaria parasite 总被引:10,自引:0,他引:10
Plasmodium falciparum, the most lethal of the malarial parasites that infect humans, undergoes three cycles of development in its vertebrate host and elicits stage-specific immune responses. This stage specificity of the immune response has made it difficult to isolate antigens that would be useful in developing a vaccine against malaria. A complementary DNA clone for a glycophorin-binding protein of Plasmodium falciparum merozoites has been isolated and characterized. The protein interacts with glycophorin, the erythrocyte receptor, during invasion of the host cell by the parasite. Antigenic determinants of this protein expressed in Escherichia coli have been used to produce antibodies to a glycophorin-binding protein. The antibodies show schizont-specific immunofluorescence and react with the merozoite protein. The primary sequence of these determinants reveals a 150-nucleotide tandem-repeating sequence coding for a 50-amino-acid repeat. The characterization of the Plasmodium falciparum glycophorin-binding protein represents one approach toward designing serologic agents to block the parasite's development in the vertebrate host. 相似文献
27.
Chromosome number of a small protist: accurate determination 总被引:9,自引:0,他引:9
Electron micrographs of serial sections through a meiotic prophase nucleus of the mycetozoan Labyrinthula sp. show that there are nine separate and distinct synaptinemal complexes. Since each complex represents a set of paired homologous chromosomes, it follows that the haploid chromosome number of this protist is nine. 相似文献
28.
Catecholamine-induced alteration in sedimentation behavior of membrane bound beta-adrenergic receptors 总被引:10,自引:0,他引:10
T K Harden C U Cotton G L Waldo J K Lutton J P Perkins 《Science (New York, N.Y.)》1980,210(4468):441-443
Incubation of astrocytoma cells with catecholamines results in a decrease in catecholamine-stimulated adenylate cyclase activity and a concomitant alteration in the sedimentation properties of particulate beta-adrenergic receptors. The altered receptors exhibit agonist binding properties similar to those of receptors that are "uncoupled" from adenylate cyclase. 相似文献
29.
Perkins RW Rancitelli LA Cooper JA Kaye JH Wogman NA 《Science (New York, N.Y.)》1970,167(3918):577-580
The (7)Be, (22)Na, (26)Al, (44)Ti, (46)SC, (48)V (51)Cr, (54)Mn, (56)Co, (57)Co, (57)CO, (40)K, (238)U, and (232)Th were measured in lunar fines and portions of three rocks. Major production of cosmogenic radionuclides is due to solar protons, thus their concentrations are far different than those in meteorites. Surface exposures of the rocks and fines are long compared with the 0.74 million year half-life of (26)Al. Lunar fines show substantially higher concentrations of low energy reaction products. The ratios of thorium to uranium are extremely constant at 3.8, which indicates very little geochemical differentiation and are in good agreement with a common nucleosynthesis for lunar and earth materials. 相似文献
30.
Wogman NA Thomas CW Cooper JA Engelmann RJ Perkins RW 《Science (New York, N.Y.)》1968,159(3811):189-192
Through recent developments in instrumental analysis it is now possible to measure with good precision the rainwater concentrations of five short-lived radionuclides which are produced by cosmic ray spallation of atmospheric argon. These measurements provide a method for studying the in-cloud nucleation times and aerosol scavenging efficiencies, and promise to provide information onshort-term processes which occur in rain and snow formation. 相似文献