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"Allometric scaling"

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https://www.readbyqxmd.com/read/29044122/wind-loads-and-competition-for-light-sculpt-trees-into-self-similar-structures
#1
Christophe Eloy, Meriem Fournier, André Lacointe, Bruno Moulia
Trees are self-similar structures: their branch lengths and diameters vary allometrically within the tree architecture, with longer and thicker branches near the ground. These tree allometries are often attributed to optimisation of hydraulic sap transport and safety against elastic buckling. Here, we show that these allometries also emerge from a model that includes competition for light, wind biomechanics and no hydraulics. We have developed MECHATREE, a numerical model of trees growing and evolving on a virtual island...
October 18, 2017: Nature Communications
https://www.readbyqxmd.com/read/29038273/pharmacokinetic-modelling-of-voriconazole-to-develop-an-alternative-dosing-regimen-in-children
#2
Silke Gastine, Thomas Lehrnbecher, Carsten Müller, Fedja Farowski, Peter Bader, Judith Ullmann-Moskovits, Oliver A Cornely, Andreas H Groll, Georg Hempel
Background. The pharmacokinetic variability of voriconazole in immunocompromised children is high and adequate exposure, particularly in the first days of therapy, is uncertain.Methods A population pharmacokinetic model was developed to explore VCZ exposure in plasma after alternative dosing regimens. Concentration data were obtained from a pediatric phase II study. Non-linear mixed effects modelling was used to develop the model. Monte Carlo simulations were performed to test an array of three times daily (TID) intravenous dosing regimens in children 2 to 12 years of age...
October 16, 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/29030928/pharmacokinetics-of-s-ketamine-during-prolonged-sedation-at-the-pediatric-intensive-care-unit
#3
Robert B Flint, Carole N M Brouwer, Anne S C Kränzlin, Loraine Lie-A-Huen, Albert P Bos, Ron A A Mathôt
BACKGROUND: S-ketamine is the S(+)-enantiomer of the racemic mixture ketamine, an anesthetic drug providing both sedation and analgesia. In clinical practice, significant interpatient variability in drug effect of S-ketamine is observed during long-term sedation. AIMS: The aim of this study was to evaluate the pharmacokinetic variability of S-ketamine in children aged 0-18 years during long-term sedation. Twenty-five children (median age: 0.42 years, range: 0...
November 2017: Paediatric Anaesthesia
https://www.readbyqxmd.com/read/29027834/extrapolation-of-plasma-clearance-to-understand-species-differences-in-toxicokinetics-of-bisphenol-a
#4
Torka Poet, Sean Hays
1. Understanding species differences in the toxicokinetics of bisphenol A (BPA) is central to setting acceptable exposure limits for human exposures to BPA. BPA toxicokinetics have been well studied, with controlled oral dosing studies in several species and across a wide dose range. 2. We analyzed the available toxicokinetic data for BPA following oral dosing to assess potential species differences and dose dependencies. BPA is rapidly conjugated and detoxified in all species. The toxicokinetics of BPA can be well described using non-compartmental analyses...
October 13, 2017: Xenobiotica; the Fate of Foreign Compounds in Biological Systems
https://www.readbyqxmd.com/read/29026726/hand-grip-strength-and-gender-allometric-normalization-in-older-adults-and-implications-for-the-niosh-lifting-equation
#5
Trish Gail Sevene, Joseph Berning, Chad Harris, Mike Climstein, Kent Jason Adams, Mark DeBeliso
BACKGROUND: Many countries are experiencing an aging workforce with women workers making up a growing proportion. Workplaces often require employees to complete lifting tasks that require the ability of the hand to grasp an implement (coupling). The National Institute for Occupational Safety and Health (NIOSH) has developed an equation for manual lifting tasks hoping to minimize the potential for a workplace back-injury related to a lifting task. The NIOSH lifting equation relies upon stress variables including a coupling factor...
July 2017: Journal of Lifestyle Medicine
https://www.readbyqxmd.com/read/29023468/the-effect-of-allometric-scaling-in-coral-thermal-microenvironments
#6
Robert H Ong, Andrew J C King, Jaap A Kaandorp, Benjamin J Mullins, M Julian Caley
A long-standing interest in marine science is in the degree to which environmental conditions of flow and irradiance, combined with optical, thermal and morphological characteristics of individual coral colonies, affects their sensitivity of thermal microenvironments and susceptibility to stress-induced bleaching within and/or among colonies. The physiological processes in Scleractinian corals tend to scale allometrically as a result of physical and geometric constraints on body size and shape. There is a direct relationship between scaling to thermal stress, thus, the relationship between allometric scaling and rates of heating and cooling in coral microenvironments is a subject of great interest...
2017: PloS One
https://www.readbyqxmd.com/read/29020021/physiological-morphological-and-ecological-tradeoffs-influence-vertical-habitat-use-of-deep-diving-toothed-whales-in-the-bahamas
#7
Trevor W Joyce, John W Durban, Diane E Claridge, Charlotte A Dunn, Holly Fearnbach, Kim M Parsons, Russel D Andrews, Lisa T Ballance
Dive capacity among toothed whales (suborder: Odontoceti) has been shown to generally increase with body mass in a relationship closely linked to the allometric scaling of metabolic rates. However, two odontocete species tagged in this study, the Blainville's beaked whale Mesoplodon densirostris and the Cuvier's beaked whale Ziphius cavirostris, confounded expectations of a simple allometric relationship, with exceptionally long (mean: 46.1 min & 65.4 min) and deep dives (mean: 1129 m & 1179 m), and comparatively small body masses (med...
2017: PloS One
https://www.readbyqxmd.com/read/28993567/reference-intervals-and-allometric-scaling-of-two-dimensional-echocardiographic-measurements-in-150-healthy-cats
#8
Schober Karsten, Savino Stephanie, Yildiz Vedat
The objective of the study was to evaluate the effects of body weight (BW), breed, and sex on two-dimensional (2D) echocardiographic measures, reference ranges, and prediction intervals using allometrically-scaled data of left atrial (LA) and left ventricular (LV) size and LV wall thickness in healthy cats. Study type was retrospective, observational, and clinical cohort. 150 healthy cats were enrolled and 2D echocardiograms analyzed. LA diameter, LV wall thickness, and LV dimension were quantified using three different imaging views...
October 6, 2017: Journal of Veterinary Medical Science
https://www.readbyqxmd.com/read/28993120/coronary-lumen-volume-to-myocardial-mass-ratio-in-primary-microvascular-angina
#9
Rominder Grover, Jonathon A Leipsic, John Mooney, Shaw-Hua Kueh, Mickael Ohana, Bjarne L Nᴓrgaard, Ashkan Eftekhari, Jeroen J Bax, Darra T Murphy, Cameron J Hague, Michael A Seidman, Philipp Blanke, Tara Sedlak, Stephanie L Sellers
BACKGROUND: Microvascular angina (MVA) is an incompletely understood clinical entity. Computational analysis of coronary Computed Tomography Angiography (CTA) has shown an association between low coronary lumen volume to myocardial mass (V/M) ratio and lower Fractional Flow Reserve values, independent of plaque measures. We hypothesized that low V/M ratio may be present in patients with MVA. METHODS: A retrospective case-control analysis was performed using patients fulfilling guideline criteria for MVA with controls matched for age, gender, coronary risk factors and atherosclerotic plaque burden...
September 22, 2017: Journal of Cardiovascular Computed Tomography
https://www.readbyqxmd.com/read/28986929/evolution-of-brain-region-volumes-during-artificial-selection-for-relative-brain-size
#10
Alexander Kotrschal, Hong-Li Zeng, Wouter van der Bijl, Caroline Öhman-Mägi, Kurt Kotrschal, Kristiaan Pelckmans, Niclas Kolm
The vertebrate brain shows an extremely conserved layout across taxa. Still, the relative sizes of separate brain regions vary markedly between species. One interesting pattern is that larger brains seem associated with increased relative sizes only of certain brain regions, for instance telencephalon and cerebellum. Till now, the evolutionary association between separate brain regions and overall brain size is based on comparative evidence and remains experimentally untested. Here we test the evolutionary response of brain regions to directional selection on brain size in guppies (Poecilia reticulata) selected for large and small relative brain size...
October 6, 2017: Evolution; International Journal of Organic Evolution
https://www.readbyqxmd.com/read/28985226/scaling-and-maintenance-of-corneal-thickness-during-aging
#11
Takenori Inomata, Alireza Mashaghi, Jiaxu Hong, Takeshi Nakao, Reza Dana
Corneal thickness is tightly regulated by its boundary endothelial and epithelial layers. The regulated set-point of corneal thickness likely shows inter-individual variations, changes by age, and response to stress. Using anterior segment-optical coherence tomography, we measure murine central corneal thickness and report on body size scaling of murine central corneal thickness during aging. For aged-matched mice, we find that corneal thickness depends on sex and strain. To shed mechanistic insights into these anatomical changes, we measure epithelial layer integrity and endothelial cell density during the life span of the mice using corneal fluorescein staining and in vivo confocal microscopy, respectively and compare their trends with that of the corneal thickness...
2017: PloS One
https://www.readbyqxmd.com/read/28975652/pharmacological-versus-classical-approaches-in-the-design-of-first-in-man-clinical-drug-trials
#12
Cornelis A van den Bogert, Adam F Cohen, Hubert G M Leufkens, Joop M A van Gerven
AIMS: To investigate the role of pharmacology in the design of first in man (FIM) trials in the Netherlands, and to evaluate the change in design approaches between 2007 and 2015. METHODS: All FIM drug trials approved by all Dutch Institutional Review Boards (IRBs) in 2007 and in 2015 were selected. The original trial protocols, investigator's brochures and investigational medicinal product dossiers were the data sources. The design elements preclinical information, dose calculation, endpoints and dose escalation were assessed on the justification of the chosen approaches...
October 4, 2017: British Journal of Clinical Pharmacology
https://www.readbyqxmd.com/read/28967696/single-dose-pharmacokinetic-study-of-diphenhydramine-hcl-in-children-and-adolescents
#13
Cathy K Gelotte, Brenda A Zimmerman, Gary A Thompson
Diphenhydramine pharmacokinetics were characterized following a single oral dose in children aged 2 to 17 years using a weight- and age-based dosing schedule with more tiers than the current age-based dosing schedule recommended by the nonprescription drug monograph. This study was conducted in 42 subjects, aged 2 to 17 years. Doses were based on a weight-age dosing schedule, ranging from 6.25 to 50 mg. An oral dose was administered with water about 2 hours after a light breakfast. Plasma samples were obtained up to 48 hours after dosing and analyzed for diphenhydramine...
October 2, 2017: Clinical Pharmacology in Drug Development
https://www.readbyqxmd.com/read/28962537/population-pharmacokinetics-of-enoxaparin-in-pediatric-patients
#14
Brady S Moffett, YoungNa Lee-Kim, Marianne Galati, Donald Mahoney, Mona D Shah, Jun Teruya, Donald Yee
BACKGROUND: There are no studies evaluating the pharmacokinetics of enoxaparin in the hospitalized pediatric patient population. OBJECTIVE: To characterize the pharmacokinetics of enoxaparin in pediatric patients. METHODS: A retrospective review of inpatients 1 to 18 years of age admitted to our institution who received enoxaparin with anti-factor Xa activity level monitoring was performed. Demographic variables, enoxaparin dosing, and anti-factor Xa activity levels were collected...
September 1, 2017: Annals of Pharmacotherapy
https://www.readbyqxmd.com/read/28937536/enoxaparin-population-pharmacokinetics-in-the-first-year-of-life
#15
Brady S Moffett, Marianne Galati, Donald Mahoney, YoungNa Lee-Kim, Jun Teruya, Mona D Shah, Donald L Yee
Aims Enoxaparin dosing requirements in the first year of life can be highly variable. Characterization of pharmacokinetics in this patient population can assist in dosing. METHODS: Patients less than one year post-natal age who received enoxaparin and had an anti-factor Xa activity level drawn as inpatients were identified through the pharmacy database over a five-year period. Patients on renal replacement therapy or with hyperbilirubinemia were excluded. Data collection included demographic variables, indication for enoxaparin, enoxaparin doses, anti-factor Xa activity levels, serum creatinine, hemoglobin, hematocrit, platelet count, and urine output over the previous 24 hours...
September 19, 2017: Therapeutic Drug Monitoring
https://www.readbyqxmd.com/read/28931936/bite-force-in-the-horned-frog-ceratophrys-cranwelli-with-implications-for-extinct-giant-frogs
#16
A Kristopher Lappin, Sean C Wilcox, David J Moriarty, Stephanie A R Stoeppler, Susan E Evans, Marc E H Jones
Of the nearly 6,800 extant frog species, most have weak jaws that play only a minor role in prey capture. South American horned frogs (Ceratophrys) are a notable exception. Aggressive and able to consume vertebrates their own size, these "hopping heads" use a vice-like grip of their jaws to restrain and immobilize prey. Using a longitudinal experimental design, we quantified the ontogenetic profile of bite-force performance in post-metamorphic Ceratophrys cranwelli. Regression slopes indicate positive allometric scaling of bite force with reference to head and body size, results that concur with scaling patterns across a diversity of taxa, including fish and amniotes (lizards, tuatara, turtles, crocodylians, rodents)...
September 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28887816/the-little-things-that-run-a-general-scaling-of-invertebrate-exploratory-speed-with-body-mass
#17
Myriam R Hirt, Tobias Lauermann, Ulrich Brose, Lucas P J J Noldus, Anthony I Dell
Speed is a key trait of animal movement, and while much is already known about vertebrate speed and how it scales with body mass, studies on invertebrates are sparse, especially across diverse taxonomic groups. Here, we used automated image-based tracking to characterize the exploratory (voluntary) speed of 173 invertebrates comprising 57 species across 6 taxonomic groups (Arachnida, Chilopoda, Diplopoda, Entognatha, Insecta, Malacostraca) and 4 feeding types (carnivore, detritivore, herbivore, omnivore). Across all individuals, exploratory speed scaled with body mass following a power-law relationship with a scaling exponent of 0...
September 8, 2017: Ecology
https://www.readbyqxmd.com/read/28867665/pharmacogenomic-variability-of-oral-baclofen-clearance-and-clinical-response-in-children-with-cerebral-palsy
#18
Matthew J McLaughlin, Yang He, Janice Brunstrom-Hernandez, Liu Lin Thio, Bruce C Carleton, Colin J D Ross, Andrea Gaedigk, Andrew Lewandowski, Hongying Dai, William J Jusko, J Steven Leeder
BACKGROUND: Pharmacogenomic variability can contribute to differences in pharmacokinetics and clinical responses. Pediatric patients with cerebral palsy with genetic variations have not been studied for these potential differences. OBJECTIVE: To determine the genetic sources of variation in oral baclofen clearance and clinical responses. DESIGN: Pharmacogenomic add-on study to determine variability in oral baclofen clearance and clinical responses...
September 1, 2017: PM & R: the Journal of Injury, Function, and Rehabilitation
https://www.readbyqxmd.com/read/28858051/long-term-changes-in-jump-performance-and-maximum-strength-in-a-cohort-of-ncaa-division-i-women-s-volleyball-athletes
#19
Ashley A Kavanaugh, Satoshi Mizuguchi, William A Sands, Michael W Ramsey, Michael H Stone
The purpose of this investigation was to quantify the magnitude of change in maximal strength and jumping abilities over approximately one, two, and three years of supervised sport and resistance training in NCAA Division I women's volleyball athletes. This was an exploratory study on a cohort of women's volleyball athletes (n=29) split into three groups based on length of time spent in a supervised resistance training program: group 1 (n=11): 0.7±0.3 yrs, group 2 (n=9): 1.6±0.2 yrs, and group 3 (n=9): 2...
August 26, 2017: Journal of Strength and Conditioning Research
https://www.readbyqxmd.com/read/28830758/the-medicinal-chemistry-and-neuropharmacology-of-kratom-a-preliminary-discussion-of-a-promising-medicinal-plant-and-analysis-of-its-potential-for-abuse
#20
REVIEW
Andrew C Kruegel, Oliver Grundmann
The leaves of Mitragyna speciosa (commonly known as kratom), a tree endogenous to parts of Southeast Asia, have been used traditionally for their stimulant, mood-elevating, and analgesic effects and have recently attracted significant attention due to increased use in Western cultures as an alternative medicine. The plant's active alkaloid constituents, mitragynine and 7-hydroxymitragynine, have been shown to modulate opioid receptors, acting as partial agonists at mu-opioid receptors and competitive antagonists at kappa- and delta-opioid receptors...
August 19, 2017: Neuropharmacology
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