By I. Navaras. American University of Hawaii.
Base pairs Purine from 1 strand of nucleic acid & pyrimidine from another strand joined by hydrogen (H) bonds discount 400mg motrin mastercard. Composition Repeating nucleotides linked by phosphodiester bonds between 5’ Repeating nucleotides linked by phosphate group of 1 sugar & 3’hydroxyl group of next generic 600mg motrin otc. Synthesis on 5’–3’template is discontinuous purchase motrin 600 mg on line, forming lagging strand of disconnected Okazaki fragments motrin 600 mg lowest price. Hybridization Pairing of complementary strands of nucleic acid, 1 from sample & 1 a reagent. Labeled with ﬂuorescent or chemiluminescent dyes, enzymes, or radioisotopes to produce visible sign of hybridization. Lysis of cells, isolation by phenol-chloroform extraction or binding to silica, precipitation in alcohol. Can be stored suspended in ethanol for several months at –20°C or long term at –70°C. Target ampliﬁcation Technique to↑amount of target nucleic acid in sample through in vitro replication, e. Probe ampliﬁcation Technique to↑amount of probe bound to target so very small amounts of nucleic acid can be detected, e. Signal ampliﬁcation Technique to↑signal generated so that very small amounts of nucleic acid can be detected, e. Polymerase Enzyme that assembles nucleotides to produce new strand of nucleic acid. Originally isolated from bacteriumThermus aquaticusin hot springs of Yellowstone National Park. Annealing (hybridization) 50°–70°C/ Primers attach to both template strands by binding with complementary 20–90 sec. Housekeeping gene detected control) & unrelated target (house- Diﬀerentiates true neg from false keeping gene or other nucleic neg due to ampliﬁcation failure. Final probe is branched & carries signal-generating enzymes that act on chemiluminescent substrate. Cleavage-based ampliﬁcation Isothermal method that uses primary probe, invader Detection of cystic ﬁbrosis, factor (Invader technology) probe, reporter probe. Labeled probe (signal-generating probe) that anneals to diﬀerent site on target added. Hybridized typing,Mycobacteriaspeciation complexes visualized with Biotin-Streptavidin method. Liquid-phase hybridization Target nucleic acid & probe interact in aqueous solution. After cancers/diseases, classiﬁcation of ampliﬁcation, sample & control nucleic acids labeled with leukemias, tumor staging, determi- 2 diﬀerent ﬂuorescent dyes & loaded onto chip. Single-stranded fragments transferred (blotted) to solid support medium by capillary action. Sequencing ladder 4-lane gel electrophoresis pattern obtained from dideoxy chain termination sequencing. Restriction site (recognition site) Nucleotide sequence recognized by restriction endonuclease. Band furthest from origin is smallest, fastest migrating fragment & ends in the 1st nucleotide in the sequence, e. Controlling Deﬁning standards of performance, developing a reporting system, & taking corrective action when necessary. Organizational goals Administrator Runs organization within framework of policies given to him/her. Work environment Supervisor Oversees activities of others to help them accomplish speciﬁc tasks.
An explanatory or independent variable is hypothesized to affect the outcome variable and is generally manipulated or controlled experimentally discount motrin 400mg mastercard. For example motrin 400mg generic, treat- ment status deﬁned as whether participants receive the active drug treatment or inactive treatment (placebo) is an independent variable motrin 600mg overnight delivery. A common error in statistical analyses is to misclassify the outcome variable as an explanatory variable or to misclassify an intervening variable as an explanatory variable order 600mg motrin with mastercard. It is important that an intervening variable, which links the explanatory and outcome 8 Chapter 1 Table 1. For example, hay fever cannot be treated as an independent risk factor for asthma because it is a symptom that is a consequence of the same allergic developmental pathway. In a case–control study in which disease status is used as the selection criterion, the explanatory variable will be the presence or absence of disease and the outcome variable will be the exposure. However, in most other observational and experimental studies such as clinical trials, cross-sectional and cohort studies, the disease will be the outcome and the exposure or the experimental group will be an explanatory variable. In hypothesis testing, a ‘null hypothesis’ is ﬁrst speciﬁed, that is a hypothesis stating that there is no difference, for example, there is no difference in the summary statistics of the study groups (placebo and treatment). The null hypothesis assumes that the groups that are being compared are drawn from the same population. An alternative hypothesis, which states that there is a difference between groups, can also be speciﬁed. The P value is then calculated, that is, the prob- ability of obtaining a difference as large as or larger than the one observed between the groups, assuming the null hypothesis is true (i. In this situation, we reject the null hypothesis and accept the alternative hypothesis, and therefore conclude that there is a statistically signiﬁcant dif- ference between the groups. In this case, we accept the null hypothesis and conclude that the difference is not attributed to sampling. A P value obtained from a test of signiﬁcance should only be interpreted as a measure of the strength of evidence against the null hypothesis. It is of paramount importance that the correct test is used to generate P values and to estimate a size of effect. Using an incorrect test will inviolate the statistical assumptions of the test and may lead to inaccurate or biased P values. The sample size needs to be large enough so that a deﬁnitive answer to the research question is obtained. However, the sample has to be small enough so that the study is practical to conduct. In general, studies with a small sample size, say with less than 30 participants, can usually only provide imprecise and unreliable estimates. The larger the sample size the more likely a difference between study groups will be statistically signiﬁcant. Therefore, it is important to carefully calculate the sample size required prior to the study commencing and also consider the sample size when interpreting the results of the statistical tests. This handbook should be available for anyone in the team to refer to at any time to facilitate considered data collection and data analysis practices. Suggested contents of data analysis log sheets that could be kept in the study handbook are shown in Box 1. In this, it is important that data are treated carefully and analysed by people who are familiar with their content, their meaning and the interrelationship between variables. Before beginning any statistical analyses, a data analysis plan should be agreed upon in consultation with the study team. The plan can include the research questions or hypotheses that will be tested, the outcome and explanatory variables that will be used, the journal where the results will be published and/or the scientiﬁc meeting where the ﬁndings will be presented. A good way to handle data analyses is to create a log sheet for each proposed paper, abstract or report. The log sheets should be formal documents that are agreed to by all stakeholders and that are formally archived in the study handbook. When a research team is managed efﬁciently, a study handbook is maintained that has up-to-date docu- mentation of all details of the study protocol and the study processes. This is especially important when the data set will be accessed in the future by researchers who are not familiar with all aspects of data collection or the coding and recoding of the variables.