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https://www.readbyqxmd.com/read/28211681/proton-coupled-electron-transfer-and-the-linear-approximation-for-coupling-to-the-donor-acceptor-distance-fluctuations
#1
Bridget Salna, Abdelkrim Benabbas, Paul M Champion
The often-used "linear approximation" for treating the coupling of donor-acceptor (D-A) distance fluctuations to proton-coupled electron transfer tunneling reactions, is systematically examined. The accuracy of this approximation is found to depend upon the potential energy surfaces that are used to describe both the tunneling particle vibrations and the D-A coordinate probability distribution. A harmonic treatment of both the tunneling particle and the D-A coordinates results in a significant breakdown of the linear approximation when the width of the D-A distribution exceeds ~0...
February 17, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28211607/physiological-motion-modeling-for-organ-mounted-robots
#2
Nathan A Wood, David Schwartzman, Marco A Zenati, Cameron N Riviere
BACKGROUND: Organ-mounted robots passively compensate heartbeat and respiratory motion. In model-guided procedures, this motion can be a significant source of information that can be used to aid in localization or to add dynamic information to static preoperative maps. METHODS: Models for estimating periodic motion are proposed for both position and orientation. These models are then tested on animal data and optimal orders are identified. Finally, methods for online identification are demonstrated...
February 17, 2017: International Journal of Medical Robotics + Computer Assisted Surgery: MRCAS
https://www.readbyqxmd.com/read/28211510/broadband-gradient-impedance-matching-using-an-acoustic-metamaterial-for-ultrasonic-transducers
#3
Zheng Li, Dan-Qing Yang, Shi-Lei Liu, Si-Yuan Yu, Ming-Hui Lu, Jie Zhu, Shan-Tao Zhang, Ming-Wei Zhu, Xia-Sheng Guo, Hao-Dong Wu, Xin-Long Wang, Yan-Feng Chen
High-quality broadband ultrasound transducers yield superior imaging performance in biomedical ultrasonography. However, proper design to perfectly bridge the energy between the active piezoelectric material and the target medium over the operating spectrum is still lacking. Here, we demonstrate a new anisotropic cone-structured acoustic metamaterial matching layer that acts as an inhomogeneous material with gradient acoustic impedance along the ultrasound propagation direction. When sandwiched between the piezoelectric material unit and the target medium, the acoustic metamaterial matching layer provides a broadband window to support extraordinary transmission of ultrasound over a wide frequency range...
February 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28210964/exploring-partners-experiences-in-living-with-patients-who-undergo-bariatric-surgery
#4
Anna Wallwork, Lynn Tremblay, Monica Chi, Sanjeev Sockalingam
BACKGROUND: Bariatric surgery is effective in assisting persons with severe obesity in achieving significant weight loss and improved health; however, success depends on one's lifelong commitment to lifestyle modifications post-operatively. Life partners can be essential to the success of bariatric patients as they can serve as a primary resource to patients and healthcare teams. This study aimed to explore bariatric patients' partner's experiences in order to help inform clinical practice in bariatric care to better address patient and partner needs...
February 16, 2017: Obesity Surgery
https://www.readbyqxmd.com/read/28210879/theoretical-study-of-the-spectroscopic-and-nonlinear-optical-properties-of-trans-and-cis-4-hydroxyazobenzene
#5
Hai-Peng Li, Ze-Tong Bi, Wen-Yue Fu, Run-Feng Xu, Yi Zhang, Xiao-Peng Shen, Ming-Xue Li, Gang Tang, Kui Han
We investigate the molecular structure, vibrational and electronic absorption spectra, and electronic hyperpolarizabilities of trans and cis isomers of 4-hydroxyazobenzene (HOAB) via density functional theory. Results show that the azo dye exhibits a high third-order nonlinear optical response and good optical transparency. Both the basis set and the functional are important influences on the results obtained when calculating the absorption spectrum and NLO response. We also study the effect of the solvent on the electronic absorption spectrum to assess the ability of the functional to reproduce the experimental spectrum in combination with a suitable solvent model...
March 2017: Journal of Molecular Modeling
https://www.readbyqxmd.com/read/28210806/the-current-state-of-orthopaedic-residency-in-18-european-countries
#6
Rami Madanat, Tatu J Mäkinen, Daniel Ryan, Gazi Huri, Nikolaos Paschos, Joao Vide
PURPOSE: The aim of this study was to compare differences in current orthopaedic and trauma training programs across Europe. METHODS: A questionnaire was sent to the FORTE (Federation of Orthopaedic Trainees in Europe) representatives of 25 different European countries, of which 18 responded. The questionnaire included demographic information and information concerning the structure of the training programs, including duration, selection, and mandatory training requirements...
February 16, 2017: International Orthopaedics
https://www.readbyqxmd.com/read/28210085/macro-and-microcirculation-patterns-of-intrahepatic-blood-flow-changes-in-patients-with-hereditary-hemorrhagic-telangiectasia
#7
Roland C Schelker, Ana P Barreiros, Christina Hart, Wolfgang Herr, Ernst-Michael Jung
AIM: To evaluated vascular dynamic processes in the liver of hereditary hemorrhagic telangiectasia (HHT) patients by ultrasound (US) considering quantitative analytic methods. METHODS: The imaging features on US and contrast-enhanced ultrasound (CEUS) in 18 patients diagnosed with HHT were retrospectively analyzed. Regarding CEUS, real-time contrast harmonic imaging and sulfur hexafluoride-filled microbubbles were used. RESULTS: HVaMs were identified in all 18 patients...
January 21, 2017: World Journal of Gastroenterology: WJG
https://www.readbyqxmd.com/read/28209417/influence-of-hospital-level-practice-patterns-on-variation-in-the-application-of-minimally-invasive-surgery-in-united-states-pediatric-patients
#8
Arianne T Train, Carroll M Harmon, David H Rothstein
BACKGROUND: Although disparities in access to minimally invasive surgery are thought to exist in pediatric surgical patients in the United States, hospital-level practice patterns have not been evaluated as a possible contributing factor. METHODS: Retrospective cohort study using the Kids' Inpatient Database, 2012. Odds ratios of undergoing a minimally invasive compared to open operation were calculated for six typical pediatric surgical operations after adjustment for multiple patient demographic and hospital-level variables...
February 2, 2017: Journal of Pediatric Surgery
https://www.readbyqxmd.com/read/28209145/state-budget-transfers-to-health-insurance-to-expand-coverage-to-people-outside-formal-sector-work-in-latin-america
#9
Inke Mathauer, Thorsten Behrendt
BACKGROUND: Contributory social health insurance for formal sector employees only has proven challenging for moving towards universal health coverage (UHC). This is because the informally employed and the poor usually remain excluded. One way to expand UHC is to fully or partially subsidize health insurance contributions for excluded population groups through government budget transfers. This paper analyses the institutional design features of such government subsidization arrangements in Latin America and assesses their performance with respect to UHC progress...
February 16, 2017: BMC Health Services Research
https://www.readbyqxmd.com/read/28208641/temporal-trends-in-satellite-derived-erythemal-uvb-and-implications-for-ambient-sun-exposure-assessment
#10
Marvin Langston, Leslie Dennis, Charles Lynch, Denise Roe, Heidi Brown
Ultraviolet radiation (UVR) has been associated with various health outcomes, including skin cancers, vitamin D insufficiency, and multiple sclerosis. Measurement of UVR has been difficult, traditionally relying on subject recall. We investigated trends in satellite-derived UVB from 1978 to 2014 within the continental United States (US) to inform UVR exposure assessment and determine the potential magnitude of misclassification bias created by ignoring these trends. Monthly UVB data remotely sensed from various NASA satellites were used to investigate changes over time in the United States using linear regression with a harmonic function...
February 10, 2017: International Journal of Environmental Research and Public Health
https://www.readbyqxmd.com/read/28208465/characterizing-classical-periodic-orbits-from-quantum-green-s-functions-in-two-dimensional-integrable-systems-harmonic-oscillators-and-quantum-billiards
#11
Y F Chen, J C Tung, P H Tuan, Y T Yu, H C Liang, K F Huang
A general method is developed to characterize the family of classical periodic orbits from the quantum Green's function for the two-dimensional (2D) integrable systems. A decomposing formula related to the beta function is derived to link the quantum Green's function with the individual classical periodic orbits. The practicality of the developed formula is demonstrated by numerically analyzing the 2D commensurate harmonic oscillators and integrable quantum billiards. Numerical analyses reveal that the emergence of the classical features in quantum Green's functions principally comes from the superposition of the degenerate states for 2D harmonic oscillators...
January 2017: Physical Review. E
https://www.readbyqxmd.com/read/28208409/thermal-transport-in-dimerized-harmonic-lattices-exact-solution-crossover-behavior-and-extended-reservoirs
#12
Chih-Chun Chien, Said Kouachi, Kirill A Velizhanin, Yonatan Dubi, Michael Zwolak
We present a method for calculating analytically the thermal conductance of a classical harmonic lattice with both alternating masses and nearest-neighbor couplings when placed between individual Langevin reservoirs at different temperatures. The method utilizes recent advances in analytic diagonalization techniques for certain classes of tridiagonal matrices. It recovers the results from a previous method that was applicable for alternating on-site parameters only, and extends the applicability to realistic systems in which masses and couplings alternate simultaneously...
January 2017: Physical Review. E
https://www.readbyqxmd.com/read/28208379/prediction-of-the-moments-in-advection-diffusion-lattice-boltzmann-method-i-truncation-dispersion-skewness-and-kurtosis
#13
Irina Ginzburg
The effect of the heterogeneity in the soil structure or the nonuniformity of the velocity field on the modeled resident time distribution (RTD) and breakthrough curves is quantified by their moments. While the first moment provides the effective velocity, the second moment is related to the longitudinal dispersion coefficient (k_{T}) in the developed Taylor regime; the third and fourth moments are characterized by their normalized values skewness (Sk) and kurtosis (Ku), respectively. The purpose of this investigation is to examine the role of the truncation corrections of the numerical scheme in k_{T}, Sk, and Ku because of their interference with the second moment, in the form of the numerical dispersion, and in the higher-order moments, by their definition...
January 2017: Physical Review. E
https://www.readbyqxmd.com/read/28208375/stable-parity-time-symmetric-nonlinear-modes-and-excitations-in-a-derivative-nonlinear-schr%C3%A3-dinger-equation
#14
Yong Chen, Zhenya Yan
The effect of derivative nonlinearity and parity-time-symmetric (PT-symmetric) potentials on the wave propagation dynamics is explored in the derivative nonlinear Schrödinger equation, where the physically interesting Scarf-II and harmonic-Hermite-Gaussian potentials are chosen. We study numerically the regions of unbroken and broken linear PT-symmetric phases and find some stable bright solitons of this model in a wide range of potential parameters even though the corresponding linear PT-symmetric phases are broken...
January 2017: Physical Review. E
https://www.readbyqxmd.com/read/28208350/l%C3%A3-vy-flights-in-the-presence-of-a-point-sink-of-finite-strength
#15
Deepika Janakiraman
In this paper, the absorption of a particle undergoing Lévy flight in the presence of a point sink of arbitrary strength and position is studied. The motion of such a particle is given by a modified Fokker-Planck equation whose exact solution in the Laplace domain can be described in terms of the Laplace transform of the unperturbed (absence of the sink) Green's function. This solution for the Green's function is a well-studied, generic result which applies to both fractional and usual Fokker-Planck equations alike...
January 2017: Physical Review. E
https://www.readbyqxmd.com/read/28208347/particles-with-nonlinear-electric-response-suppressing-van-der-waals-forces-by-an-external-field
#16
Heino Soo, David S Dean, Matthias Krüger
We study the classical thermal component of Casimir, or van der Waals, forces between point particles with highly anharmonic dipole Hamiltonians when they are subjected to an external electric field. Using a model for which the individual dipole moments saturate in a strong field (a model that mimics the charges in a neutral, perfectly conducting sphere), we find that the resulting Casimir force depends strongly on the strength of the field, as demonstrated by analytical results. For a certain angle between the external field and center-to-center axis, the fluctuation force can be tuned and suppressed to arbitrarily small values...
January 2017: Physical Review. E
https://www.readbyqxmd.com/read/28208343/collective-colloid-diffusion-under-soft-two-dimensional-confinement
#17
S Panzuela, Raúl P Peláez, R Delgado-Buscalioni
This work presents a numerical and theoretical investigation of the collective dynamics of colloids in an unbounded solution but trapped in a harmonic potential. Under strict two-dimensional confinement (infinitely stiff trap) the collective colloidal diffusion is enhanced and diverges at zero wave number (like k^{-1}), due to the hydrodynamic propagation of the confining force across the layer. The analytic solution for the collective diffusion of colloids under a Gaussian trap of width δ still shows enhanced diffusion for large wavelengths kδ<1, while a gradual transition to normal diffusion for kδ>1...
January 2017: Physical Review. E
https://www.readbyqxmd.com/read/28208177/feasibility-and-associated-limitations-of-office-based-laryngeal-surgery-using-carbon-dioxide-lasers
#18
Hao-Chun Hu, Shu-Yi Lin, Yi-Ting Hung, Shyue-Yih Chang
Importance: There are few reports evaluating awake, office-based carbon dioxide (CO2) laser surgery for laryngeal lesions. To date, this study was the largest reported case series of office-based laryngeal surgery by fiber delivery CO2 laser. Office-based laryngeal surgical procedures have become increasingly popular. Technical problems and treatment outcomes associated with the use of a CO2 laser for office-based laryngeal surgery have yet to be fully addressed. Objectives: To discuss a single institution's clinical experience with office-based CO2 laser laryngeal surgery and the feasibility and limitations associated with this procedure...
February 16, 2017: JAMA Otolaryngology—Head & Neck Surgery
https://www.readbyqxmd.com/read/28207780/analyzing-pepsin-degradation-assay-conditions-used-for-allergenicity-assessments-to-ensure-that-pepsin-susceptible-and-pepsin-resistant-dietary-proteins-are-distinguishable
#19
Rong Wang, Thomas C Edrington, S Bradley Storrs, Kathleen S Crowley, Jason M Ward, Thomas C Lee, Zi L Liu, Bin Li, Kevin C Glenn
The susceptibility of a dietary protein to proteolytic degradation by digestive enzymes, such as gastric pepsin, provides information on the likelihood of systemic exposure to a structurally intact and biologically active macromolecule, thus informing on the safety of proteins for human and animal consumption. Therefore, the purpose of standardized in vitro degradation studies that are performed during protein safety assessments is to distinguish whether proteins of interest are susceptible or resistant to pepsin degradation via a study design that enables study-to-study comparison...
2017: PloS One
https://www.readbyqxmd.com/read/28207306/a-comprehensive-review-of-spirit-drink-safety-standards-and-regulations-from-an-international-perspective
#20
Xiao-Na Pang, Zhao-Jie Li, Jing-Yu Chen, Li-Juan Gao, Bei-Zhong Han
Standards and regulations related to spirit drinks have been established by different countries and international organizations to ensure the safety and quality of spirits. Here, we introduce the principles of food safety and quality standards for alcoholic beverages and then compare the key indicators used in the distinct standards of the Codex Alimentarius Commission, the European Union, the People's Republic of China, the United States, Canada, and Australia. We also discuss in detail the "maximum level" of the following main contaminants of spirit drinks: methanol, higher alcohols, ethyl carbamate, hydrocyanic acid, heavy metals, mycotoxins, phthalates, and aldehydes...
February 16, 2017: Journal of Food Protection
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