The recent work has been made possible by new techniques of molecular biology that allow viral DNA to be detected at low concentrations in the environment.
分子生物学的新技术使最近的工作成为可能，这种新技术能在环境中检测到低浓度的病毒DNA。
Even caffeine, which is generally known only for its stimulatory effects, displays this property, depressing mouse locomotion at very low concentrations and stimulating it at higher ones.
就连人们通常觉得有刺激作用的咖啡因，也表现出了这种特性，它在浓度极低的情况下会抑制老鼠的运动，而在浓度较高的情况下则会刺激老鼠。
Very low concentrations of vanadium, which is scarce in meats and somewhat lower in nuts than in other plant resources, are good evidence of meat consumption and thus a better-balanced diet.
极低浓度的钒在肉类中很少见，在坚果中的含量也比在其他植物资源中较少，这很好地证明了吃肉的好处，从而使得饮食也更加均衡。
These areas have particularly low concentrations of iron, and oceanographers hypothesize that this shortage of iron prevents plankton from thriving.
这些地区的铁含量特别低，海洋学家推测，铁的缺乏阻碍了浮游生物的繁殖。
Dogs require vitamins in their food, albeit at low concentrations.
狗需求维生素的食物，固然低浓度。
Sometimes also in saliva, but not to low concentrations can be spread.
唾液中有时也有，但浓度可以低到不能进行传播。
In both cases, high concentrations of the gas are dark, while low concentrations are light.
在两幅图中，气体密度越高的区域颜色也就越深，低密度区则更浅。
Among them, the lead had toxic effects on plants and human health even at low concentrations.
铅甚至在低浓度下对植物有毒害作用，而且会对人的身体健康造成极大的危害。
The experiments showed that low concentrations of ADO improved the resistance of plant seedlings.
表明低浓度的褐藻胶寡糖有利于提高植物幼苗的抗性。
Even relatively low concentrations of air pollutants have been related to a range of adverse health effects.
即便空气污染物的浓度相对偏低，它也与一系列的健康副效应相关。
At low concentrations it can have a positive effect on cells, but a negative effect at high concentrations.
低浓度条件下对细胞有积极作用，反之则有负面影响。
The alternating-doping profile region may include alternating regions of high and low concentrations of a dopant.
交替掺杂形态区域包含高低掺杂浓度的交替区域。
Spectrometry is preferably used each time extremely low concentrations and isotopic abundance are to be determined.
每当测定非常低的浓度和同位素丰度时总是首先使用无机质谱法。
The seaside’s “bracing” smell is caused by a chemical produced by coastal bacteria, present in very low concentrations.
答：并不完全如此。 海风的气味让人振奋是缘于一种沿海细菌的化学产物，尽管它在空气中比例甚微。
It was observed early that low concentrations of sodium bisulfite treatment increased net photosynthetic rate in leaves.
人们很早就已观察到低浓度亚硫酸氢钠处理能提高叶片净光合速率。
When measuring a shallow diffused layer at low concentrations, reliable measurement free of noise are difficult to make.
测量低浓度浅扩散层时，无干扰的可靠测量很难实行。
At low concentrations, enzyme activity declined sharply, leveled off gradually with the increasing of toxic concentration.
在低浓度时，酶活性急剧下降，随着毒物浓度的增加逐渐趋于平缓。
Farm animals were long raised outdoors in relatively low concentrations, but that changed dramatically in the 20th century.
农场里的家畜长时间在室外散养，养殖密度低，但是二十世纪以来情况发生了显著的变化。
Results: All immunized mice developed high titers of serum antibodies to ZP and low concentrations of serum estradiol(P< 0.01 ).
结果：免疫小鼠外周血抗ZP抗体滴度明显高于对照组（P＜0．01），而雌二醇浓度则明显低于对照组（P＜0．01）；
The left image shows high ozone concentrations over most of the planet, but very low concentrations—the ozone hole—over the Arctic.
作图显示了地球上大部分地区都被高浓度的臭氧所覆盖，但在北极上空却有一片极低值区——也就是臭氧洞。
Inorganic Mass Spectrometry is preferably used each time extremely low concentrations and isotopic abundance are to be determined.
每当测定非常低的浓度和同位素丰度时总是首先使用无机质谱法。
At low concentrations ROS induce expression of defence genes and adaptive response, at high concentrations cell death is initiated.
在低浓度时，ROS能诱导防御基因的表达和引起适应反应；在高浓度时，引起细胞死亡。
The results indicate that collagen I, the main organic component of bone, has been preserved in low concentrations in these tissues.
结果显示骨的主要有机成份I型胶原在这些组织中保存下来的浓度很低。
Florfenicol at low concentrations induces the activities of SOD, CAT and POD, while florfenicol at high concentrations inhibits the activities.
低质量比氟苯尼考对SOD,CAT和POD酶活性具有诱导作用，而在高质量比条件下则表现为抑制作用。
In comparison with small chemical drugs, protein and peptide pharmaceuticals have high specificity and activity at relatively low concentrations.
与小分子的化学药物相比，蛋白质和多肽的特点是在相对较低的浓度下就有较高的特异性和活性。
The search process is simple and the results are exact. It is suitable for spectra search, which have low concentrations and unsharp absorption peaks.
具有过程简单，结果比较准确的特点，很适合低浓度，峰形不明显的谱图检索。
Sugars in low concentrations are detected by mass detector, while those in high concentrations are detected by differential reflective index detector.
以质量检测器测定浓度小的糖份，以示差折射率检测器测定浓度大的糖份。
Where you've got residual levels of low concentrations of disinfectant and the resistant organisms are present, they become dominant in the environment.
在可以发现低浓度的消毒剂残留物的地方，同样有耐药性微生物的存在，而这些(耐药性微生物)将在那些环境中占尽优势。
Purification of waste gases containing toluene in low concentrations with high airflow load was preliminarily investigated by using a biotrickling filter.
采用净化甲苯专用菌种对生物膜填料塔净化处理高流量负荷下低浓度甲苯废气的技术进行了初步实验研究。
Although the causality of the effects of low concentrations of SO2 is still uncertain, reducing SO2 concentrations is likely to decrease exposure to co-pollutants.
尽管二氧化硫低浓度效应的因果关系尚不确定，但是，降低二氧化硫浓度很可能减少对混合污染物的暴露。
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