Effect of pooling samples on the efficiency of comparative studies using microarrays

Many biomedical experiments are carried out by pooling individual biological samples. However, pooling samples can potentially hide biological variance and give false confidence concerning the data significance. In the context of microarray experiments for detecting differentially expressed genes, recent publications have addressed the problem of the efficiency of sample-pooling, and some approximate formulas were provided for the power and sample size calculations. It is desirable to have exact formulas for these calculations and have the approximate results checked against the exact ones. We show that the difference between the approximate and exact results can be large. In this study, we have characterized quantitatively the effect of pooling samples on the efficiency of microarray experiments for the detection of differential gene expression between two classes. We present exact formulas for calculating the power of microarray experimental designs involving sample pooling and technical replications. The formulas can be used to determine the total numbers of arrays and biological subjects required in an experiment to achieve the desired power at a given significance level. The conditions under which pooled design becomes preferable to non-pooled design can then be derived given the unit cost associated with a microarray and that with a biological subject. This paper thus serves to provide guidance on sample pooling and cost effectiveness. The formulation in this paper is outlined in the context of performing microarray comparative studies, but its applicability is not limited to microarray experiments. It is also applicable to a wide range of biomedical comparative studies where sample pooling may be involved.Comment: 8 pages, 1 figure, 2 tables; to appear in Bioinformatic

The Relationship Between the Population\u27s Perception of Herniated Intervertebral Disks and Their Known Physical Presentation

The second most common lumbosacral diagnosis in the United States is a herniation or prolapse of the intervertebral disc. Individuals with herniated discs can have a wide variety of clinical presentations, ranging from asymptomatic to severe spinal cord compression and pain. Studies suggest that an individual’s pre-existing perception of a condition is likely to influence their course of recovery. Currently, perceptions the general public holds regarding the consequences of disc herniation is unknown. Therefore, the purpose of this study was to assess current views regarding disc herniations in the general population with their reported prevalence and clinical outcome. This was determined via an electronic Qualtrics survey. This survey included demographic questions, medical history questions, disk herniation perception questions, and coping/resilience questions. Upon conclusion of survey administration, data analysis was performed via JASP. A key finding of this study was that resilience levels play a major role in participant’s views on herniated intervertebral discs (p=0.040). Participants with greater resilience levels had views on disc herniations that were more consistent with the findings in the literature (p=0.018). This may implicate low resilience levels in negative catastrophizing, which can impair the recovery process for patients. Due to this, healthcare providers should further consider a patient’s mental characteristics such as resilience and coping style when administering treatment. By further educating patients on their specific prognosis for a disc herniation, providers may be able to improve their overall perception of herniated discs, leading to a possible improvement in outcome

Apparatus for Leak Testing Pressurized Hoses

A hose-attaching apparatus for leak-testing a pressurized hose may include a hose-attaching member. A bore may extend through the hose-attaching member. An internal annular cavity may extend coaxially around the bore. At least one of a detector probe hole and a detector probe may be connected to the internal annular cavity. At least a portion of the bore may have a diameter which is at least one of substantially equal to and less than a diameter of a hose to be leak-tested

Abnormal platelet activity in dogs and cats – impact and measurement

Abnormal platelet activity can either lead to bleeding tendencies or inappropriate thrombus formation and can occur secondarily to a wide variety of disease processes, with a range of clinical consequences and severity. This article will discuss the pathophysiology of platelet function abnormalities and consider a logical diagnostic approach applicable to veterinary practice. Recent advances in platelet function testing will then be discussed, with regards to detection of platelet dysfunction and tailoring of pharmacological manipulation. Although many of these tests are still confined to research or academic institutions, techniques for indirectly assessing platelet function are starting to become more widely available. Although we still require further research to develop guidelines for the use of these tests in clinical decision‐making, the recent advances in this field are an exciting step forward in being able to detect and manage platelet dysfunction in both primary care and referral practice

Urban tourism and population change: Gentrification in the age of mobilities

The prepandemic unbridled growth of tourism has triggered a significant debate regarding the future of cities; several authors suggest that neighbourhood change produced by tourism should be conceived as a form of gentrification. Yet research on population shifts—a fundamental dimension of gentrification—in such neighbourhoods is scarce. Our exploration of the Gòtic area in Barcelona, using quantitative and qualitative techniques, reveals a process of population restructuring characterised by a decrease of long-term residents and inhabited dwellings, and the arrival of young and transnational gentrifiers that are increasingly mobile and form a transient population. We then use some insights from the mobilities literature to make sense of these results. In the gentrification of the Gòtic, the attractiveness of the area for visitors and for a wider palette of transnational dwellers feeds one another, resulting in an uneven negotiation whereby more wealthy and ‘footloose’ individuals gain access and control of space and housing over less mobile and more dependent populations.info:eu-repo/semantics/publishedVersio

Guidance for a large tabletop exercise for a nuclear power plant

Tabletop exercises are held to discuss issues related to the response of organizations to an emergency event. This document describes in task format the planning, conduct, and reporting of lessons learned for a large interagency tabletop. A sample scenario, focus areas, and discussion questions based on a simulated accident at a commercial nuclear power plant are provided

Calcium\u27s Role as Nuanced Modulator of Cellular Physiology in the Brain

Neuroscientists studying normal brain aging, spinal cord injury, Alzheimer’s disease (AD) and other neurodegenerative diseases have focused considerable effort on carefully characterizing intracellular perturbations in calcium dynamics or levels. At the cellular level, calcium is known for controlling life and death and orchestrating most events in between. For many years, intracellular calcium has been recognized as an essential ion associated with nearly all cellular functions from cell growth to degeneration. Often the emphasis is on the negative impact of calcium dysregulation and the typical worse-case-scenario leading inevitably to cell death. However, even high amplitude calcium transients, when executed acutely can alter neuronal communication and synaptic strength in positive ways, without necessarily killing neurons. Here, we focus on the evidence that calcium has a subtle and distinctive role in shaping and controlling synaptic events that underpin neuronal communication and that these subtle changes in aging or AD may contribute to cognitive decline. We emphasize that calcium imaging in dendritic components is ultimately necessary to directly test for the presence of age- or disease-associated alterations during periods of synaptic activation