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71.
OBJECTIVE: To compare cardiac output (CO) measured by use of the partial carbon dioxide rebreathing method (NICO) or lithium dilution method (LiDCO) in anesthetized foals. SAMPLE POPULATION: Data reported in 2 other studies for 18 neonatal foals that weighed 32 to 61 kg. PROCEDURES: Foals were anesthetized and instrumented to measure direct blood pressure, heart rate, arterial blood gases, end-tidal isoflurane and carbon dioxide concentrations, and CO. Various COs were achieved by administration of dobutamine, norepinephrine, vasopressin, phenylephrine, and isoflurane to allow comparisons between LiDCO and NICO methods. Measurements were obtained in duplicate or triplicate. We allowed 2 minutes between measurements for LiDCO and 3 minutes for NICO after achieving a stable hemodynamic plane for at least 10 to 15 minutes at each CO. RESULTS: 217 comparisons were made. Correlation (r = 0.77) was good between the 2 methods for all determinations. Mean +/- SD measurements of cardiac index for all comparisons with the LiDCO and NICO methods were 138 +/- 62 mL/kg/min (range, 40 to 381 mL/kg/min) and 154 +/- 55 mL/kg/min (range, 54 to 358 mL/kg/min), respectively. Mean difference (bias) between LiDCO and NICO measurements was -17.3 mL/kg/min with a precision (1.96 x SD) of 114 mL/kg/min (range, -131.3 to 96.7). Mean of the differences of LiDCO and NICO measurements was 4.37 + (0.87 x NICO value). CONCLUSIONS AND CLINICAL RELEVANCE: The NICO method is a viable, noninvasive method for determination of CO in neonatal foals with normal respiratory function. It compares well with the more invasive LiDCO method.  相似文献   
72.
为探究江苏稻茬小麦不同栽培模式下产量差异形成的原因,明确提高产量的调控途径,以小麦品种扬麦25为材料,分别在江苏省扬州市和兴化市两地种植,设置高密无氮(Y0,基本苗300×10~4株·hm~(-2),不施氮)、高密高氮(Y1,300×10~4株·hm~(-2),施氮300 kg·hm~(-2))、低密中高氮(Y2,150×10~4株·hm~(-2),施氮270 kg·hm~(-2))和中密中氮(Y3,225×10~4株·hm~(-2),施氮240 kg·hm~(-2))4种栽培模式,对不同栽培模式下小麦产量和群体结构的差异进行了分析。结果表明,扬州和兴化试验点产量均表现为Y3Y1Y2Y0,其中Y3与Y1及Y1与Y2模式的平均产量差值分别为434.54和312.82 kg·hm~(-2)。经通径分析,穗数差和粒重差是导致模式间产量差形成的主要原因。相关分析表明,乳熟期叶面积指数差、开花至乳熟期绿叶面积持续时间(LAD)差与产量差均呈显著正相关,花后干物质积累量差、孕穗至开花期绿叶面积持续时间差与产量差均呈极显著正相关。总体来看,基本苗225×10~4株·hm~(-2)、施氮量240 kg·hm~(-2)、基肥∶壮蘖肥∶拔节孕穗肥为5∶1∶4的栽培模式能够使稻茬小麦保持花后较高的叶面积指数和绿叶面积持续期,提高花后干物质积累量,是缩小产量差的主要调控途径。  相似文献   
73.
Energy flow in biological structures often requires submillisecond charge transport over long molecular distances. Kinetics modeling suggests that charge-transfer rates can be greatly enhanced by multistep electron tunneling in which redox-active amino acid side chains act as intermediate donors or acceptors. We report transient optical and infrared spectroscopic experiments that quantify the extent to which an intervening tryptophan residue can facilitate electron transfer between distant metal redox centers in a mutant Pseudomonas aeruginosa azurin. Cu(I) oxidation by a photoexcited Re(I)-diimine at position 124 on a histidine(124)-glycine(123)-tryptophan(122)-methionine(121) beta strand occurs in a few nanoseconds, fully two orders of magnitude faster than documented for single-step electron tunneling at a 19 angstrom donor-acceptor distance.  相似文献   
74.
Hematuria, with some erythrocytes also appearing in the urine, was observed in male albino rats given 20 percent and 40 percent ethanol in lieu of drinking water for several weeks. However, the amounts of hemoglobin in the blood of the treated group did not change relative to those of the control group; this finding indicates that the degree of hematuria was not sufficient to produce an anemia.  相似文献   
75.
为明确花后阶段高、低温胁迫对冬小麦光合特性、籽粒发育及产量形成的影响,利用人工智能控温室开展盆栽小麦高、低温度胁迫试验,以宁麦13和镇麦12为试验材料,在花后7~9、15~17、23~25和 31~33 d分别进行低温和高温胁迫处理,并在温度胁迫后喷施1 μmol·L-1 2,4-表油菜素内酯(BR)、0.5 mol·L-1 亚精胺+腐胺(Spd+Put)进行减灾调控,分析小麦旗叶净光合速率、SPAD值、籽粒形态、产量变化及减灾调控效果。结果表明,与自然温度处理相比,花后不同阶段低温胁迫结束当天小麦旗叶SPAD值先升高,3 d后显著下降;高温胁迫后SPAD值降低4.67%~29.00%。两品种旗叶净光合速率在高、低温胁迫处理下均降低。高、低温胁迫显著降低粒宽,增加籽粒长宽比,导致籽粒表面皱缩。籽粒灌浆时间在花后低温胁迫下延长1~3 d,在高温胁迫下缩短1~5 d。温度胁迫后优势和弱势小穗籽粒灌浆速率分别下降2.75%~37.64%和3.31%~ 40.34%,产量降低5.46%~35.24%。温度胁迫后喷施BR与Spd+Put均能缓解温度胁迫的伤害,使产量分别提高1.09%~6.05%和1.00%~5.97%。综上,花后不同阶段高、低温胁迫均显著降低小麦粒重与产量,影响程度表现为花后15~17 d>花后7~9 d>花后23~25 d>花后31~33 d,胁迫结束后喷施外源BR和Spd+Put有一定的减灾效果,特别是花后15~17 d和23~25 d灾后喷施BR效果较佳。  相似文献   
76.
A Gram-positive bacterium with antagonistic activity was isolated from the soil. It has been identified as Bacillus amyloliquefaciens strain V656 on the basis of 16S ribosomal DNA analysis and standard bacteriological tests. B. amyloliquefaciens V656 produced antifungal enzymes when it was grown in a medium containing shrimp and crab shell powder (SCSP) of marine waste. The antifungal enzymes displayed chitinase activities. Two extracellular antifungal chitinases (FI and FII) were purified and characterized, and their molecular weights, isoelectric points, pH and thermal stabilities, and antifungal activities were determined. The characteristics of V656 chitinases are similar to those of the known bacterial chitinases in terms of their isoelectric points, thermal instabilities, and lack of lysozyme activity. In contrast to other known bacterial chitinases, the unique characteristics of V656 chitinases include extremely low molecular weights and nearly neutral optimum pH. Furthermore, this is the first report of the isolation of chitinases from B. amyloliquefaciens that are active against fungi.  相似文献   
77.
Farm ponds provide a home for birds and numerous species of aquatic animals in Taoyuan, Taiwan. Urbanization and development of infrastructure resulted in the gradual disappearance of these ponds. Currently, only 3800 ponds originally approximately 15.4 % remain, and 84.6 % of the surface area of the ponds has vanished. Aiming to protect avian diversity, this study used logistic regression analysis and the geostatistical approach to analyze the relationship between avian diversity and landscape structure, in an effort to elucidate the spatial driving force of avian diversity. We detected that regression-kriging (RK) was even more accurate than logistic regression (LR). In addition, the value of diversity (H′) measures may decrease instead of increase when evenness (J′) is increased. The results of this study also indicated that an exceedingly strong relationship existed among avian diversity and landscape scale, agricultural landscape indices, and pond landscape indices. The models predict that preservation of large areas of waterscapes and paddy landscapes result in greater diversity of avian species. Spatial estimation of the research area indicated that human activity substantially affected avian ecology, leading to reductions in avian diversity. Thus, the reduction of the area of ecological corridors due to urban development is expected to further reduce avian diversity in the Taoyuan region. Our approach can be used to effectively analyze the correlations between characteristics of ecosystems and the environmental landscape, to ensure that pondscapes can be appropriately maintained and ecological reserves designated to prevent further decline in avian diversity.  相似文献   
78.
A method was developed for estimating tuber yield losses caused by late blight of potato (Phytophthora infestans) (Mont.) de Bary. The method is based on yield and disease data collected for the varieties Green Mountain and Katahdin grown in eastern Canada during the period 1953–1970. The percentage yield loss can be calculated for any disease progress curve. The estimated loss was within 5% of the actual loss in nine cases out of ten.  相似文献   
79.
Objective To determine if systemic administration of lidocaine during intraocular surgery reduces post-operative ocular pain. Study design Randomized, masked, controlled experimental trial. Animals Twelve dogs weighing 15.5 ± 1.7 kg (mean ± SD) and aged 2.5 ± 0.6 years. Methods All dogs underwent a baseline ophthalmic examination and subjective pain score. Anesthesia consisted of acepromazine (0.1 mg kg−1, IM), propofol (4–6 mg kg−1, IV), and isoflurane in oxygen. There were three groups each receiving a bolus followed by an infusion (n = 4): saline (0.3 mL kg−1 IV + 0.2 mL kg−1hour−1 IV); morphine (0.15 mg kg−1 IV + 0.1 mg kg−1hour−1 IV); and lidocaine (1.0 mg kg−1 IV + 0.025 mg kg−1minute−1 IV). All treatments began 15 minutes prior to starting of phacoemulsification and lens removal from the right eye. Pain scores were recorded at 0.5, 1, 2, 3, 4, 6, 8, 16, and 24 hours after t = 0 (extubation). Rescue morphine was administered (1.0 mg kg−1 IM) if the subjective pain score ≥9 (maximum = 24), and the dog was excluded from further data analysis. Differences in pain scores and time-to-treatment failure (TTF) were analyzed using the Wilcoxon's rank sum test. Differences in incidence of treatment failure were analyzed using Fisher's exact test. Physiologic data were analyzed using repeated measures anova . Significance was defined as P < 0.05. Results Incidence of treatment failure was 100% in saline-treated dogs and 50% in morphine- or lidocaine-treated dogs. There was no difference in intraocular pressure, aqueous flare, cell count (or protein) between groups in the operated eye at any time following extubation. Conclusion and clinical relevance This pilot study suggests that intraoperative lidocaine may provide analgesic benefits similar to morphine for intraocular surgery in dogs, but more definitive research is needed. This model appears to be appropriate for pain assessment studies as the negative control group demonstrated 100% failure rate.  相似文献   
80.
[目的]研究杉木间伐初始期与立地之间的关系,为大径材培育的间伐初始期的确定提供科学的依据.[方法]采用福建峡阳23年生的杉木人工林的长期定位观测数据,研究目标树胸径连年生长量的变化规律,分析立地指数及不同株数梯度的目标树对杉木人工林首次间伐期的影响.[结果](1)地位指数明显影响林分中幼龄时期目标树的胸径生长速率及连年...  相似文献   
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