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Scott Seaman, Paul Nelson, Jacob Alexander, Andrew Swift, James Fick
The authors present the case of a 53-year-old man who was referred with disabling retching provoked by left arm abduction. At the time of his initial evaluation, a cervical MRI study was available for review and revealed an anatomical variation of the ipsilateral juxtamedullary vertebrobasilar junction. After brain imaging revealed contact of the medulla by a dolichoectatic vertebral artery at the dorsal root entry zone of the glossopharyngeal and vagus nerves, the patient was successfully treated by microvascular decompression of the brainstem and cranial nerves...
October 21, 2016: Journal of Neurosurgery
David M Turer, Kelly L Koch, Todd M Koelling, Audrey H Wu, Francis D Pagani, Jonathan W Haft
Centrifugal and axial flow left ventricular assist devices have different hydrodynamic properties that may impact the effectiveness of left ventricular unloading. We sought to determine if patients implanted with the HeartWare HVAD (HW) and HeartMate II (HMII) had a similar degree of hemodynamic support by comparing parameters measured using echocardiography and right heart catheterization. Using our prospectively collected database, we identified 268 patients implanted with the HMII and 93 with the HW. Demographic characteristics were similar between groups...
July 26, 2016: ASAIO Journal: a Peer-reviewed Journal of the American Society for Artificial Internal Organs
Colin James Stockdale Klaus, Krishnan Raghunathan, Emmanuele DiBenedetto, Anne K Kenworthy
Diffusion of particles in curved surfaces is inherently complex compared with diffusion in a flat membrane owing to the non-planarity of the surface. The consequence of such non-planar geometry on diffusion is poorly understood but is highly relevant in the case of cell membranes, which often adopt complex geometries. To address this question, we developed a new finite element approach to model diffusion on curved membrane surfaces based on solutions to Fick's law of diffusion and used this to study the effects of geometry on the entry of surface-bound particles into tubules by diffusion...
October 12, 2016: Molecular Biology of the Cell
Herman N C Berghuijs, Xinyou Yin, Q Tri Ho, Steven M Driever, Moges A Retta, Bart M Nicolaï, Paul C Struik
One way to increase potential crop yield could be increasing mesophyll conductance gm. This variable determines the difference between the CO2 partial pressure in the intercellular air spaces (Ci) and that near Rubisco (Cc). Various methods can determine gm from gas exchange measurements, often combined with measurements of chlorophyll fluorescence or carbon isotope discrimination. gm lumps all biochemical and physical factors that cause the difference between Cc and Ci. gm appears to vary with Ci. This variability indicates that gm does not satisfy the physical definition of a conductance according to Fick's first law and is thus an apparent parameter...
November 2016: Plant Science: An International Journal of Experimental Plant Biology
Shahid A Punwar, Daniel P Fick, Riaz J K Khan
BACKGROUND: Obtaining adequate exposure while maintaining the integrity of the extensor mechanism is crucial to the success of revision knee arthroplasty. This is particularly important in infected cases where staged procedures are necessary. While the use of a long, tibial tubercle osteotomy (TTO) is an established method to improve exposure, controversy still exists concerning complication rates and sequential use. METHODS: Forty-two TTOs were performed in revision knee arthroplasties between 2009 and 2015...
September 3, 2016: Journal of Arthroplasty
Rachel Fickes, Dennis R Voelker, Karin Zemski Berry, Robert C Murphy
RATIONALE: Structural analogs of the bioactive lipid, 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoglycerol, were synthesized with a xylitol polar headgroup and both diacyl and diether radyl groups. Mass spectral characterization of xylitol phospholipids (PX) was carried out using collisional activation and high resolution mass measurements of positive molecular ion species and compared with the phosphatidylglycerol (PG) analogs. METHODS: Xylitol phospholipids were synthesized using a transphosphatidylation reaction catalyzed by phospholipase D and purified by HPLC...
September 30, 2016: Rapid Communications in Mass Spectrometry: RCM
G Edward Miller, Eric M Sarpong, Amy J Davidoff, Eunice Y Yang, Nicole J Brandt, Donna M Fick
OBJECTIVE: To examine the determinants of potentially inappropriate medication (PIM) use. DATA SOURCES/STUDY SETTING: U.S. nationally representative data on (n = 16,588) noninstitutionalized older adults (age ≥65) with drug use from the 2006-2010 Medical Expenditure Panel Survey. STUDY DESIGN: We operationalized the 2012 Beers Criteria to identify PIM use during the year, and we examined associations with individual-level characteristics hypothesized to be quality enabling or related to need complexity...
September 29, 2016: Health Services Research
Lin Foo, Jerome Cornette, Jasmine Tay, Christoph Lees
INTRODUCTION: There are multiple modalities used to measure cardiac output in pregnancy. The accepted gold standard is cardiac catheterisation, then measurement via direct Fick method or thermo-dilution. These methods are invasive and not feasible for assessment of healthy pregnant women. There are several non-invasive devices widely used to measure cardiac output including Innocor, an inert gas re-breathing technique which has been validated against thermodilution [1-3] and direct Fick methods [4,5] for measurement of pulmonary blood flow and thus, cardiac output...
August 2016: Journal of Maternal-fetal & Neonatal Medicine
Andreas Heller, Cédric Giraudet, Zoi A Makrodimitri, Matthieu S H Fleys, Jiaqi Chen, Gerard P van der Laan, Ioannis G Economou, Michael H Rausch, Andreas P Fröba
Theoretical approaches suggest that dynamic light scattering (DLS) signals from low-molecular-weight ternary mixtures are governed by fluctuations in temperature as well as two individual contributions from fluctuations in concentration that are related to the eigenvalues of the Fick diffusion matrix. Until now, this could not be proven experimentally in a conclusive way. In the present study, a detailed analysis of DLS signals in ternary mixtures consisting of n-dodecane (n-C12H26) and n-octacosane (n-C28H58) with dissolved hydrogen (H2), carbon monoxide (CO), or water (H2O) as well as of n-C12H26 or n-C28H58 with dissolved H2 and CO is given for temperatures up to 523 K and pressures up to 4...
October 12, 2016: Journal of Physical Chemistry. B
Scott M Tintle, Christopher LeBrun, James R Ficke, Benjamin K Potter
Traumatic and trauma-related amputations represent unfortunate sequelae of severe injury, but should not be viewed as a treatment failure and may represent the best reconstructive option for some patients. Lessons from recent military conflicts have guided the evolution of modern surgical techniques and rehabilitation management of this challenging patient population, and treatment at a specialty center may improve patient outcomes. Despite appropriate management, however, surgical complications remain common and revision surgery is often necessary...
October 2016: Journal of Orthopaedic Trauma
Alessandro Morandi, Daniel Davis, Giuseppe Bellelli, Rakesh C Arora, Gideon A Caplan, Barbara Kamholz, Ann Kolanowski, Donna Marie Fick, Stefan Kreisel, Alasdair MacLullich, David Meagher, Karen Neufeld, Pratik P Pandharipande, Sarah Richardson, Arjen J C Slooter, John P Taylor, Christine Thomas, Zoë Tieges, Andrew Teodorczuk, Philippe Voyer, James L Rudolph
Delirium occurring in patients with dementia is referred to as delirium superimposed on dementia (DSD). People who are older with dementia and who are institutionalized are at increased risk of developing delirium when hospitalized. In addition, their prior cognitive impairment makes detecting their delirium a challenge. The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition and the International Statistical Classification of Diseases and Related Health Problems, 10th Revision are considered the standard reference for the diagnosis of delirium and include criteria of impairments in cognitive processes such as attention, additional cognitive disturbances, or altered level of arousal...
September 16, 2016: Journal of the American Medical Directors Association
Jiaqi Wang, Xiaoshan Zhang, Zhangwei Wang, Ronghua Kang
Many forest ecosystems in the world are suffering from high load of nitrogen (N) deposition and acting as potential contributors to atmospheric nitric oxide (NO), which regulates the oxidative capacity of the troposphere. However, the observation of NO flux with traditional dynamic chamber method is laborious in the forest ecosystem, particularly when the electric power generation system is unavailable. In this work, a relative method based on Fick's law of diffusion was developed to measure NO fluxes from forest soils...
September 17, 2016: Science of the Total Environment
Jay R Ebert, Peter K Edwards, Daniel P Fick, Gregory C Janes
CONTEXT: Gluteus medius rehabilitation is of critical importance given its role in pelvic and lower limb stability, and the known link between gluteus medius weakness and many lower limb conditions. OBJECTIVE: To systematically review the literature and present an evidence-based graduated series of exercises to progressively load gluteus medius. EVIDENCE ACQUISITION: A systematic literature search was conducted in January 2016 to identify studies reporting gluteus medius muscle activity as a percentage of maximal volitional isometric contraction (%MVIC), during rehabilitation exercises...
August 24, 2016: Journal of Sport Rehabilitation
Eniko Borbas, Balint Sinko, Oksana Tsinman, Konstantin Tsinman, Eva Kiserdei, Balazs Demuth, Attila Balogh, Brigitta Bodak, Andras Domokos, Gergo Dargo, György T Balogh, Zsombor K Nagy
The aim of this study was to investigate the impact of formulation excipients and solubilizing additives on dissolution, supersaturation and membrane transport of an active pharmaceutical ingredient (API). When a poorly water-soluble API is formulated to enhance its dissolution, additives, such as surfactants, polymers and cyclodextrins have an effect not only on dissolution profile, but also on the measured physicochemical properties (solubility, pKa, permeability) of the drug while the excipient is present, therefore also affect the driving force of membrane transport...
September 9, 2016: Molecular Pharmaceutics
A Ziepke, S Martens, H Engel
We investigate wave propagation in rotationally symmetric tubes with a periodic spatial modulation of cross section. Using an asymptotic perturbation analysis, the governing quasi-two-dimensional reaction-diffusion equation can be reduced into a one-dimensional reaction-diffusion-advection equation. Assuming a weak perturbation by the advection term and using projection method, in a second step, an equation of motion for traveling waves within such tubes can be derived. Both methods predict properly the nonlinear dependence of the propagation velocity on the ratio of the modulation period of the geometry to the intrinsic width of the front, or pulse...
September 7, 2016: Journal of Chemical Physics
Pradip Chakraborty, Yu Jin, Charles J Barrows, Scott T Dunham, Daniel R Gamelin
Ion exchange, in which an in-diffusing ion replaces a lattice ion, has been widely exploited as a synthetic tool for semiconductor doping and solid-to-solid chemical transformations, both in bulk and at the nanoscale. Here, we present a systematic investigation of cation-exchange reactions that involve the displacement of Mn(2+) from CdSe nanocrystals by Cd(2+) or In(3+). For both incoming cations, Mn(2+) displacement is spontaneous but thermally activated, following Arrhenius behavior over a broad experimental temperature range...
October 5, 2016: Journal of the American Chemical Society
Tyler A Fick, Carl H Backes
No abstract text is available yet for this article.
September 23, 2016: Circulation Journal: Official Journal of the Japanese Circulation Society
Shaked Regev, Niels Grønbech-Jensen, Oded Farago
We study the dynamics of Brownian particles in a heterogeneous one-dimensional medium with a spatially dependent diffusion coefficient of the form D(x)∼|x|^{c}, at constant temperature. The particle's probability distribution function (PDF) is calculated both analytically, by solving Fick's diffusion equation, and from numerical simulations of the underdamped Langevin equation. At long times, the PDFs calculated by both approaches yield identical results, corresponding to subdiffusion for c<0 and superdiffusion for 0<c<1...
July 2016: Physical Review. E
Pavol Kalinay
The effective one-dimensional description of diffusion in two-dimensional channels of varying cross section is revisited. The effective diffusion coefficient D(x), extending Fick-Jacobs equation, depending on the longitudinal coordinate x, is derived here without use of scaling of the transverse coordinates. The result of the presented method is an integral formula for D(x), calculating its value at x as an integral of contributions from the neighboring positions x^{'} depending on h(x^{'}), a function shaping the channel...
July 2016: Physical Review. E
Candelas Pérez Del Villar, Raquel Yotti, María Ángeles Espinosa, Enrique Gutiérrez-Ibañes, Alicia Barrio, María José Lorenzo, Pedro Luis Sánchez Fernández, Yolanda Benito, Raquel Prieto, Esther Pérez David, Pablo Martínez-Legazpi, Francisco Fernández-Avilés, Javier Bermejo
OBJECTIVES: The goal of this study was to determine the functional impact of paradoxical low-gradient aortic stenosis (PLGAS) and clarify whether the relevance of the valvular obstruction is related to baseline flow. BACKGROUND: Establishing the significance of PLGAS is particularly challenging. METHODS: Twenty symptomatic patients (77 ± 6 years of age; 17 female subjects) with PLGAS (mean gradient 28 ± 6 mm Hg; aortic valve area 0.8 ± 0...
August 20, 2016: JACC. Cardiovascular Imaging
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