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Clinical Trials: the Statistician's Role
Published in Trevor F. Cox, Medical Statistics for Cancer Studies, 2022
and then α is calculated using a K-fold integral of the multivariate normal pdf. For and 5, the corresponding values of α are 0.107, 0.126 and 0.142, if always using a critical region, . As K approaches ∞, α approaches 1.
Monte Carlo Simulation of Photon Transport Phenomena: Sampling Techniques
Published in Richard L. Morin, Monte Carlo Simulation in the Radiological Sciences, 2019
Inspection of Equation 13 reveals that P(β |β ′) is a conditional PDF, showing that photon transport is a Markov process. That is, the probability that a photon experiences its nth collision at β is given by the transition probability which depends soley on , the photon state just prior to its (n - l)th collision. More fundamentally, Equation 12 implies that the solution χ(β ) is equivalent to the set of all possible random walks through β -space.
Pharmacological Management of the Patient with Obesity
Published in James M. Rippe, Lifestyle Medicine, 2019
Magdalena Pasarica, Nikhil V. Dhurandhar
Certain safety concerns about phentermine-topiramate ER have been raised. The small increase in heart rate has prompted the FDA to recommend a long-term study to evaluate the effect of the combination drug on heart attacks and strokes, which has not been completed yet (https://www.fda.gov/ForConsumers/ConsumerUpdates/ucm312380.htm). Meanwhile, the company recommends monitoring the heart rate of all patients taking this treatment (https://www.qsymia.com/pdf/prescribing-information.pdf). Because phentermine-topiramate ER increases the risk for cleft palate in pregnant women in the first trimester, there is a required negative pregnancy test before the beginning of the treatment and every four weeks after that. In addition, all prescribing healthcare providers and dispensing pharmacies need a special certification (https://www.fda.gov/downloads/drugs/drugsafety/postmarketdrugsafetyinformationforpatientsandproviders/ucm312598.pdf).
Pigment-dispersing factor and CCHamide1 in the Drosophila circadian clock network
Published in Chronobiology International, 2023
Riko Kuwano, Maki Katsura, Mai Iwata, Tatsuya Yokosako, Taishi Yoshii
Pigment-dispersing factor (PDF) is the most prominent neurotransmitter that connects s-LNv neurons with other clock neurons (Im and Taghert 2010; Shafer et al. 2008) and is expressed in both s-LNv and l-LNv groups (Helfrich-Förster 1995). The loss of PDF causes an internal desynchronisation among clock neurons and reduces the amplitude of molecular oscillations in the brain, leading to a fragile free-running activity rhythm in DD (Klarsfeld et al. 2004; Lin et al. 2004; Peng et al. 2003; Renn et al. 1999; Yoshii et al. 2009b). In LD, the behavioural phenotypes of Pdf mutants include reduced morning activity and phase-advanced evening activity. PDF in s-LNv neurons is involved in DD free-running rhythm and morning activity, whereas in l-LNv neurons, it is involved in the adjustment of the evening activity phase (Cusumano et al. 2009; Grima et al. 2004; Menegazzi et al. 2017; Shafer and Taghert 2009; Stoleru et al. 2004).
Orcokinin neuropeptides regulate sleep in Caenorhabditis elegans
Published in Journal of Neurogenetics, 2020
Madison Honer, Kristen Buscemi, Natalie Barrett, Niknaz Riazati, Gerald Orlando, Matthew D. Nelson
C. elegans sleep is regulated by neuropeptides. Developmentally timed sleep (DTS) occurs during larval transitions, coincident with the molt (Raizen et al., 2008; Singh & Sulston, 1978). Movement quiescence during DTS is controlled primarily by the RIS neuron which releases FLP-11 neuropeptides (Turek, Besseling, Spies, Konig, & Bringmann, 2016; Turek, Lewandrowski, & Bringmann, 2013) with a minor role for NLP-22 peptides released from the RIA neurons (Nelson et al., 2013). Arousal during DTS is mediated by pigment dispersing factor (PDF) neuropeptides, which also mediate arousal in insects (Choi, Chatzigeorgiou, Taylor, Schafer, & Kaplan, 2013; Renn, Park, Rosbash, Hall, & Taghert, 1999). SIS is controlled by both the ALA and RIS interneurons, via the release of a collection of neuropeptides (Lenz, Xiong, Nelson, Raizen, & Williams, 2015; Nelson et al., 2014; Turek et al., 2016). Based on their spatial and temporal expression patterns, and on their roles in regulating behavioral rhythms in other ecdysozoans, we hypothesized that NLP-14 and NLP-15 play a role in sleep regulation in C. elegans.
Dstac is required for normal circadian activity rhythms in Drosophila
Published in Chronobiology International, 2018
I-Uen Hsu, Jeremy W. Linsley, Jade E. Varineau, Orie T. Shafer, John Y. Kuwada
The Drosophila brain contains a network of neurons that express clock genes and regulate circadian locomotion (Nitabach and Taghert 2008). A subset of neurons that expresses the pigment dispersing factor (PDF) neuropeptide is critical for rhythmicity of locomotor behavior. These are the large and small ventrolateral neurons (l-LNVs and s-LNVs) (Helfrich-Forster 1997; Renn et al. 1999). Genetic ablation of PDF+ neurons, genetic silencing of PDF+ neurons and null mutations in pdf all disrupt circadian rhythms in locomotion (Renn et al. 1999; Nitabach et al. 2002; Sheeba et al. 2010). Specific knockdown of PDF in s-LNV neurons disrupts circadian locomotion; demonstrating the critical role of PDF in the s-LNV neurons for circadian rhythms (Shafer and Taghert 2009). Furthermore PDF, sNPF, which is another neuropeptide expressed by s-LNv neurons, and light act to set the phases of circadian neurons that are sequentially active via inhibition of Ca2+ activity in these neurons (Liang et al. 2017). This includes negative feedback onto the s-LNV neurons. Thus proper activity of PDF+ neurons is key to proper circadian rhythm.