半衰期

Passively acquired immunity in young pig has a half-life of about 9 days.

幼猪的被动免疫力的半衰期约为9天。

However, the spent fuel of the Actinides is a headache for all parties.

这些元素的半衰期(一半的物质因衰变转化为其他元素所需时间)只有几年。

So we adopted the isotope marking method in order to know the distribution of BBP in male and female mice. The result indicated 〓H-BBP presented the first-order kinetics and matched the open two-compartment model. Distributional half-life was about 20 minutes and eliminable half-life was about 6-7 hours. As α(the speed constant of distributional phase) was about ten times β(the speed constant of eliminable phase), this compound had a fast distribution and a low elimination.

为了揭示BBP致毒有明显性别差异的原因，采用同位素标记方法示踪BBP在雄、雌动物体内的归趋，结果表明：BBP在动物体内呈一级动力学线性过程，符合二室开放模型，分布半衰期为20min左右，消除半衰期为6-7hr左右，分布相的速度常数α是消除相的速度常数β的10倍左右，说明该化合物在体内的分布较快、消除慢的特征。

Kopin et al, estimate that exogenously administered melatonin disappears from whole mice with a half-life of about 2 min through the first 10 min following injection but that after 40 min the half-life has grown to about 35 min.

Kopin等人，估计外部褪黑素从整个小鼠消失的半衰期在注射后的最初10分钟里，大约为2分钟，但注射后40分钟后半衰期就增长到约35分钟。

The results showed that the better gastightness the warehouse have,the longer time the PH 3 effective concentration can maintain,and the better fumigation effect can be achieved.

在半衰期为 78秒的 4 5号仓和半衰期为 5 4秒的 4 9号仓进行环流熏蒸效果对比试验，试验结果表明，气密性越好，维持PH3气体有效浓度的时间越长，熏蒸效果也越好。

At the same time, the change of the fluorescence and the activity was detected when the enzyme was thermally denatured.

结果表明，该酶的稳定性非常好，蛋白的质量浓度为0.4 mg/mL时， 90 ℃的半衰期为20 h， 0.2 mg/mL时的半衰期为12 h；而蛋白的质量浓度为0.04 mg/mL时，保温2.5 h时残余活力仍在50%以上。

The results summarized as follows:(1)The main pharmacokinetic parameters Tmax was about 2h, Cmax was 8.365, 7.519, 1.871, 6.485, 4.060μg/mL in blood, gill, kidney, liver, and muscle respectively, after oral administration at a dose of 30 mg/kg; while t1/2 were 8.180~23.249h. These showed that the NFLX absorption was rapid after oral administration of NFLX in Scophthalmus maximus, but the residence time in the fish was long.(2) T1/2 were 74.88~200.45h after oral administration at dose of 30 mg/kg for five consecutive days, which showed that the attenuation of NFLX in the fish body was slow and the residue concentration in the kidney was the highest.

另外，本文测定了大菱鲆成鱼体内NFLX的药物浓度，用MCP-KP药动学程序对所得的药物浓度-时间数据进行分析，结果表明：1单次混饲口灌(30 mg/kg体重日)NFLX，药物在大菱鲆体内的达峰时间为2h，血液、腮、肾脏、肝脏、肌肉达峰浓度分别为：8.365、7.519、1.871、6.485、4.060μg/mL，消除半衰期为8.180～23.249h，说明NFLX在大菱鲆体内吸收较迅速，但滞留时间较长。2连续五天混饲口灌(30 mg/kg体重日)NFLX，消除半衰期为74.88～200.45h，说明混饲口灌NFLX在大菱鲆体内消除缓慢，其中以肾脏中残留最显著。

According to "EPA Fate, Transport and Transformation Test Guidelines, OPPTS 835.3170—Shake Flask Die-Away Test" and "OECD Test Guidelines of Chemical 309", a simulated biodegradation experiment was conducted with the organic pollutant parathion-methyl. First-order biodegradation rate constants for water and sediment were -0.053 and -0.295 d-1, respectively, and half-lives were 13.1 and 2.3 d, respectively.

试验结果表明，甲基对硫磷在天然地表水中生物降解一级速率常数为：-0.053 d-1；在天然地表水沉积物中生物降解一级速率常数为：-0.295d-1；在地表水中生物降解半衰期为：13.1d；在地表水沉积物中生物降解半衰期为：2.3d。

Short-lived radionuclides and long-lived isotope systems are normally used to date chondrites; the former systems can provide only relative ages while the later can provide absolute formation ages of chondrules, in contrast.

陨石年代学研究中常用定年工具包括短半衰期和长半衰期放射性同位素体系，其中前者可以给出陨石形成的相对年龄，而后者则可以给出绝对形成年龄。

In the intestinal and live homogenates,the half-lives of 5\'-L-valyl-ara-C were 46 and 34 min,respectively.

在大鼠胃液、小肠液和胃液中，5\'-L-valyl-ara-C的半衰期分别是28.4 h、7.5 h和84 min.5，-L-valyl-ara-C在小肠匀浆和肝匀浆中的半衰期很短，预示该前药口服吸收后，首过效应应该是其转化成母药的主要方式。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。