Carry over effect

Historical instrumental problems (plugging with larger samples, carry-over effects)... 

There is the possibility of carry-over effects. This is more crucial in Latin square and other cross-over designs. Knowledge of pharmacokinetics and metabolism of a compound under study generally helps in avoiding this problem. 

Tewe 00, Maner JH. 1981a. Long-term and carry-over effect of dietary inorganic cyanide (KCN) in the life cycle performance and metabolism of rats. Toxicol Appl Pharmacol 58 1-7. 

SCIEX API 365 equipped with a TurboIonSpray interface operated in positive ion mode. The calibration range 0.124-497 ng/mL was readily validated with a negligible carry-over effect from this system. The method offered a total cycle time of 8 min and completely eliminated the manual sample preparation. ... 

Two studies have been performed so far on women with breast cancer complaining of hot flushes - neither showed an improvement (Table 4.4). Quella et al. (2000) did not show any reduction in hot flushes in breast cancer survivors using 150 mg of phytoestrogen in tablets. The study was a cross-over design and had two phases lasting only four weeks, which were not separated by a wash-out period thus a carry-over effect cannot be excluded. 

Crossover designs are susceptible to carry-over effects, that is, the treatment effect from the first period has not worn off at the time of conducting the second period. Tests of analysis can detect carry-over effects, but it is too late then to modify the design. Similarly, period effects may confound the interpretation of cross-over studies, that is, the order in which one treatment occurs in a sequence compared with another influences the response to early treatment. Randomisation usually, but not always, precludes the effect. 

The major benefit of this design is the associated reduction in variability. This allows investigators to use smaller participant numbers to detect a specific response. This trial type, however, may only be used if there is sufficient evidence to show there is no carry-over effect from the first half to the second half of the trial. An extreme example of non-conformance to this requirement would be if the patient received the test drug during the first phase and was completely cured by it. 

It is important therefore to only use these designs when you can be sure that carry-over effects will not be seen. Introducing a washout period between period I and period II can help to eliminate carry-over so that when the subject enters period II their disease condition is similar to what it was at the start of period I. Cross-over designs should not be used where there is the potential to affect the underlying disease state. ICH E9 is very clear on the use of these designs. 

Carriages and mounts testings 2 C69 Cariere (poudre de) 2 C69 Carronade 2 C69—C70 Carry-over effect 2 C70 Cartouche (Fr) 2 C70 Cartouche a balle (Fr) 2 C70... 

Carry-Over Effect. Under certain conditions, the passage of a detonation wave across the interface of two different explosives may cause the first expl to overdrive the second expl such that its pressure deton velocity are higher than normal for a certain distance until a steady state rate is reached. This phenomenon is called the "carry -over effect and is discussed in detail by Pike Weir (Ref 6). It is related to detonation by influence previously described by several investigators (Refs 1 to 5)... 

Leirer, V.O., Yesavage, J.A., and Morrow, D.G., Marijuana carry-over effects on aircraft pilot performance, Aviat. Space Environ. Med., 62, 221, 1991. 

Yesavage, J.A. et al., Carry-over effects of marijuana intoxication on aircraft pilot performance a preliminary report, Am. 3. Psychiatry, 142, 1325, 1985. 

From the medical point of view, in contrast to the analytical which refers to the mechanism of sensor signal formation, a direct measurement is defined as a measurement carried out directly in undiluted sample (whole blood, plasma, serum, urine, etc.), whereas indirect measurement employ sample dilution. For an analytical chemist, a direct measurement is more challenging because of small sample volume, interferences and matrix effects, diffusion potential and carry-over effects, and the influence on the sensor lifetime due to high extracta-bility of active components by undiluted samples such as serum or urine. However, this measurement method has one important advantage it allows the measurement of the activity of analytes as-they-are . For... 

An indirect measurement with an ISS has several advantages less sample volume is required, the effects of the interferences and matrix are reduced, diffusion potential and carry-over effects become easier to control and the sensor lifetime is extended. The application of diluent itself offers the possibility of imposing the physical and chemical properties of the diluent on the sample, such as pH, ionic strength and even undesirable interferences and influences suppression. 

Carskadon MA, Seidel F, Greenblatt DJ, Dement WC. Daytime carry-over effects of triazolam and flurazepam in elderly insomniacs. Sleep 1982 5 361-371. 

One of the difficulties in comparative smelling stems from the fact that the sample that is smelled second is strongly affected by our perception of the first, especially if the two are smelled in quick succession. Adaptation causes the first sample to appear stronger than the second. In addition a carry-over effect may occur in which a clearly perceived note in the first appears also to be present in the second, even if this is not the case. To minimize such effects, it is best not to dwell too long on either sample before going on to the other. However, the pause must not be too long since the recall of complex notes quickly loses its sharpness. 

In this framework, it should be carefully taken into account that there are many causes of potential chemical contamination in the laboratory. Among these, of primary importance are dust (due to unfiltered air and/or lower air pressure in the laboratory), smokers hands, abrasion of metallic surfaces through glassware and porcelain, flakes of paint, corrosion on metallic surfaces due to the use of strong acids, carry-over effects from uncontrolled dishwashing, and contaminated chemicals. 

Because SPME is a single-step technique — which minimizes sources of random errors associated with transfer of the analytes — it exhibits very good precision with clean, model samples. In fact, the precision of SPME is typically in the region of 5% (as RSD) with manual operation and can be as low as 1% with model samples processed using an auto-sampler. On the other hand, complex matrices and carry-over effects can result in RSD values as high as 92% [226,227],... 

Fruit) preparations are always applied when a typical taste, smell, fruit content -(smooth or pulp structure, based on concentrate, puree or fruit pieces) are looked for in the end product. Sometimes (fruit) preparations are added in order to obtain a particular viscosity or consistency in the finished product. This carry-over effect is not at least due to the hydrocolloids and modified starches contained in fruit preparations. 

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