Boundary layer profiles in plasma chemical vapor deposition     

Green DS  Owano TG  Williams S  Goodwin DG  Zare RN  Kruger CH 《Science (New York, N.Y.)》1993,259(5102):1726-1729

A nonlinear optical spectroscopy based on degenerate four-wave mixing has made possible direct measurements of species temperature and concentration profiles through the boundary layer of a reactive plasma at atmospheric pressure. Spectra were obtained for CH and C(2) radicals over a range of conditions including those for the plasma chemical vapor deposition of diamond films. Numerical simulations based on a one-dimensional stagnation-point flow model are in good agreement with the measurements. The CH mole fraction is shown to rise and fall as a function of distance from the substrate, which is compelling experimental evidence for the complex chemistry that is occurring in the plasma boundary layer.  相似文献   

小麦D~2型细胞质光敏雄性不育性的研究     

于天峰  刁艳玲  车京玉  迟永琴  李长辉  王岩  邵立刚  张爱民  鄂立柱 《东北农业大学学报》2002,33(4):324-330

D2型细胞质与有些普通小麦材料的细胞核互作,可产生特异核质互作不育现象,其中有的表现为长光照敏感型雄性不育。文章研究了具有D2型细胞质的光敏不育系Ae.crassa—Norin26、核质杂种NC2134及克引11、克引12在黑龙江省克山地区自然条件下的育性表现,并以NC2134为细胞质供体,与20个小麦品种(系)杂交,获得一些核质代换系材料,对其育性及主要性状进行观察研究。结果表明:(1)在自然条件下,播种期对育性有影响,随着播种期推迟,Ae.crassa—Norin26不育度增加,1 999年4月22日播种达到全不育,Norin26则在所设播种条件下表现正常可育;(2)NC2134表现可育,这与其可能携带雄性不育的恢复基因有关,克引11、克引12在正常播种情况下表现高度不育甚至全不育;(3)不育系的不育性表现为不同程度的雄蕊心皮化;(4)不同普通小麦材料其核质杂种育性表现不同,有些材料其核质代换低世代分离出一定比例的高不育、半不育及可育株,通过进一步的核置换,可转育成相应的D2型细胞质不育系。  相似文献   

Tumor DNA structure in plant cells transformed by A. tumefaciens   总被引：25，自引：0，他引：25  

P Zambryski  M Holsters  K Kruger  A Depicker  J Schell  M Van Montagu  H M Goodman 《Science (New York, N.Y.)》1980,209(4463):1385-1391

Crown gall tumors are induced in plants by infection with the soil bacterium Agrobacterium tumefaciens. Because the tumor induction involves transfer of a portion of the tumor-inducing (Ti) plasmid DNA from the bacterium to the plant cells, this system is of interest for the study of genetic exchange as well as tumor induction. The boundaries of the transferred DNA (T-DNA) have been cloned from transformed plant cells of tobacco. Detailed mapping with restriction enzymes and nucleotide sequence analysis of two independent clones were used to study the molecular structure of the ends of the T-DNA. One clone contains the two ends of the T-DNA joined together; the other contains one end of the T-DNA joined to repetitive plant DNA sequences. These studies provide direct evidence that the T-DNA can be integrated into the plant genome. In addition, the data suggest that in the plant, T-DNA can be tandemly repeated. Sequence analysis of the junction of crown gall clone 1 reveals several direct repeats as well as an inverted repeat; these structures may be involved in the transfer of the DNA from Agrobacterium to plant cells.  相似文献   

Excitation Gap in the Normal State of Underdoped Bi2Sr2CaCu2O8+delta     

AG Loeser  Z Shen  DS Dessau  DS Marshall  CH Park  P Fournier  A Kapitulnik 《Science (New York, N.Y.)》1996,273(5273):325-329

Angle-resolved photoemission experiments reveal evidence of an energy gap in the normal state excitation spectrum of the cuprate superconductor Bi2Sr2CaCu2O8+delta. This gap exists only in underdoped samples and closes around the doping level at which the superconducting transition temperature Tc is a maximum. The momentum dependence and magnitude of the gap closely resemble those of the dx2-y2 gap observed in the superconducting state. This observation is consistent with results from several other experimental techniques, which also indicate the presence of a gap in the normal state. Some possible theoretical explanations for this effect are reviewed.  相似文献   

Preliminary investigation of concurrent administration of phenylbutazone and romifidine in healthy horses     

Kruger K  Stegmann GF  Becker PJ 《Veterinary anaesthesia and analgesia》2011,38(5):505-509

ObjectiveTo characterize the cardiorespiratory and electrocardiographic effects of the combined administration of phenylbutazone and romifidine.Study designProspective four-period, four-treatment, blinded, randomized, crossover trial.AnimalsFive, healthy, mixed breed horses.MethodsPrior to treatment administration, a catheter was introduced into the intra-thoracic cranial vena cava via the jugular vein and a subcutaneously located carotid artery was catheterised. All treatments were administered intravenously (IV) and consisted of saline placebo (PLC), phenylbutazone (PBZ, 4.4 mg kg^?1) romifidine (ROM, 80 μg kg^?1) and a combination of phenylbutazone (4.4 mg kg^?1) and romifidine (80 μg kg^?1). There was at least a 1 week washout period between treatments. Heart rate (HR), respiratory rate (f_R), systolic (SAP), diastolic (DAP) and mean (MAP) arterial pressures and central venous pressure (CVP) were recorded for baseline (prior to drug administration) and at 5 minute intervals thereafter for 30 minutes. Electrocardiographic abnormalities were recorded. Data were analyzed by anova.ResultsFor the cardiovascular variables there were no statistically significant (p > 0.05) differences between horses treated with ROM and PBZ_ROM. Statistically significant (p < 0.05) differences only occurred between treatments with romifidine (ROM and PBZ_ROM) and without romifidine (PLC and PBZ). Within treatments, for ROM, changes over time were statistically significant (p < 0.05) for HR, SAP, DAP, MAP and CVP. For PBZ_ROM, changes over time were statistically significant (p < 0.05) for CVP. Sino-atrial and atrio-ventricular blocks occurred in horses treated with ROM and PBZ_ROM.Conclusions and clinical relevanceThe combined IV administration of phenylbutazone and romifidine had no statistically significant effect on cardiorespiratory variables. These limited data suggest no evidence why both agents should not be included in a preoperative medication protocol for healthy horses but do not exclude the possibility of interactions occurring in a larger population.  相似文献   

Enzyme electrophoresis of South African Schistosoma mattheei and S. haematobium     

F J Kruger 《The Onderstepoort journal of veterinary research》1987,54(1):93-96

As a pilot project of a study undertaken to determine the influence of S. mattheei X S. haematobium hybridization on various South African S. mattheei populations by means of biochemical-taxonomic methods, a comparative electrophoretic study of laboratory-maintained S. mattheei and S. haematobium was performed, using 11 enzymes representing 16 gene loci. Eleven loci were found to be monomorphic, while 5 differed interspecifically. Computation of the results revealed that South African S. mattheei and S. haematobium are fairly closely related when compared with other Schistosoma spp. groups.  相似文献   

First Report of Post‐Weaning Multisystemic Wasting Syndrome and Porcine Dermatitis and Nephropathy Syndrome in Pigs in Greece     

K. SAOULIDIS  S. C. KYRIAKIS  S. KENNEDY  S. LEKKAS  CH. C. MILIOTIS  G. ALLAN  G. C. BALKAMOS  P. A. PAPOUTSIS 《Zoonoses and public health》2002,49(4):202-205

Post‐weaning multisystemic wasting syndrome (PMWS) and porcine dermatitis and nephropathy syndrome (PDNS) are two recently described conditions of pigs at the late nursery and fattening stages. The aim of this short communication was to describe the first reported occurrence of these conditions and of porcine circovirus type 2 (PCV2) infection in Greece. The clinical signs, gross post‐mortem changes and histopathological changes observed in affected pigs, were similar to those previously described for both PDNS and PMWS. As in previous reports, the lesions were associated with PCV2 infection, which was demonstrated by immunohistochemical and in situ hybridization methods.  相似文献   

Further observations on the electrophoretic characterization of South African Schistosoma mattheei and S. haematobium     

F J Kruger 《The Onderstepoort journal of veterinary research》1988,55(1):67-68

Eleven enzymes, which were used to compare South African S. mattheei and S. haematobium in a former study, were employed to study intraspecific variation within S. mattheei, using starch gel electrophoresis and iso-electric focusing where resolution in starch gel was poor. Acid phosphatase varied intraspecifically within S. mattheei in that the most southern population differed from the northern populations. Malate dehydrogenase also varied intraspecifically. Three populations which occur sympatric with S. haematobium had a MDH-1 allele in common with the human schistosome while an allopatric population did not.  相似文献   

Immediate relief of feline urethral obstruction     

C A Osborne  G E Lees  D J Polzin  J M Kruger 《Veterinary Clinics of North America: Small Animal Practice》1984,14(3):585-597

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The determinants of overweight and obesity among 10- to 15-year-old schoolchildren in the North West Province, South Africa - the THUSA BANA (Transition and Health during Urbanisation of South Africans; BANA, children) study     

Kruger R  Kruger HS  Macintyre UE 《Public health nutrition》2006,9(3):351-358

AIM: To investigate the determinants of overweight and obesity among 10- to 15-year-old schoolchildren in a population in the transitional phase in the North West Province of South Africa.METHODS: A cross-sectional survey was used to investigate weight status (anthropometric indicators) and determinants of overweight/obesity including dietary intake, physical activity and socio-economic status. A single, random sample (n=1257), stratified for gender, type of school and ethnic group, was used. Data were collected on demographics, family circumstances, habitual physical activity, dietary intake and anthropometry to evaluate weight status and body fat content. One-way analysis of variance, the generalised linear models procedure of SAS and the Tukey post hoc honest significant difference test were used to analyse the data.RESULTS: Few children were overweight or obese (7.8%) according to International Obesity Task Force (IOTF) standards (body mass index (BMI)-for-age). These standards were compared with other accepted standard values. Both Cole's IOTF/BMI-for-age standard and the sum of skinfold thicknesses standard classified normal-weight status similarly at a level of 92% (P<0.01) and were found to be useful in determining overweight/obesity. The prevalence rate was higher in females and white children, and was more apparent in urban areas, smaller households and children of parents with low- or high-income occupations. Boys and pre-menarcheal girls had mean body fat percentage in the normal/optimal range, whereas that of post-menarcheal girls was moderately high. Few variables showed a significant association with high body fat percentage: in boys, only the number of members in the household and physical activity levels over the weekend; in girls, only age. The overweight/obese boys mostly lived in smaller households, and the overweight/obese post-menarcheal girls were most inactive on both weekdays and weekends, and more overweight with increasing age.CONCLUSION: Smaller households, inactivity and increasing age for girls were found to be determinants that influence the development of overweight/obesity, while female gender and age post-menarche were identified as determinants of higher body fat content. For overweight/obesity prevention, the focus should be on pre-menarcheal girls, aged 10-13 years, using these determinants to identify overweight/obesity risk. Preventive programmes should aim to increase the physical activity of children to improve their current and future weight status.  相似文献