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Thomas Schmidt, Alan J Situ, Tobias S Ulmer
The solvation of membrane proteins by both lipids and water makes their membrane immersion difficult to predict and the choice of a membrane mimic challenging. To characterize protein-lipid contacts and bicelle membrane mimics, we examined protein-lipid cross-relaxation of integrin αIIb and β3(A711P) transmembrane helices in isotropic phospholipid bicelles (q=0.5 and 0.7). Long-chain bicelle lipids dominated contacts with central helix segments, whereas both short- and long-chain lipids contacted the terminal turns of each helix in corroboration of the mixed bicelle model...
October 24, 2016: Journal of Physical Chemistry Letters
Clare F Megarity, Julian Esselborn, Suzannah V Hexter, Florian Wittkamp, Ulf-Peter Apfel, Thomas Happe, Fraser A Armstrong
Protein film electrochemistry (PFE) has been used to study the assembly of the complex 6Fe active site of [FeFe]-hydrogenases (known as the H-cluster) from its precursors the [4Fe 4S] domain that is already coordinated within the host and the 2Fe domain that is presented as a synthetic water-soluble complex stabilized by an additional CO. Not only does PFE allow control of redox states via the electrode potential, but the immobilized state of the enzyme facilitates control of extremely low concentrations of the 2Fe complex...
October 24, 2016: Journal of the American Chemical Society
Ulrike Herberg, Katharina Linden, Oliver Dewald, Eva Gatzweiler, Matthias Seehase, Georg Daniel Duerr, Jonas Dörner, Stephanie Kleppe, Dennis Ladage, Johannes Breuer
BACKGROUND: Pressure-volume loops (PVL) provide vital information regarding ventricular performance and pathophysiology in cardiac disease. Unfortunately, acquisition of PVL by conductance technology is not feasible in neonates and small children due to the available human catheter size and resulting invasiveness. The aim of the study was to validate the accuracy of PVL in small hearts using volume data obtained by real-time three-dimensional echocardiography (3DE) and simultaneously acquired pressure data...
2016: PloS One
Zhenqin Wu, Huimin Bi, Sichen Pan, Lingyi Meng, Xin Sheng Zhao
Fluorescence correlation spectroscopy (FCS) is a powerful tool to investigate molecular diffusion and relaxations, which may be utilized to study many problems, such as molecular size and aggregation, chemical reaction, molecular transportation and motion, and various kinds of physical and chemical relaxations. This paper focuses on a problem related to using the relaxation term to study a reaction. If two species with different fluorescence photon emission efficiencies are connected by a reaction, the kinetic and equilibrium properties will be manifested in the relaxation term of the FCS curve...
October 24, 2016: Journal of Physical Chemistry. B
P Rodríguez Iglesias, V Ibáñez Pradas, A Alamar Velázquez, I Ibáñez Alcañiz, M Couselo Jerez
INTRODUCTION: The cricopharyngeal achalasia is an esophageal motor disorder that entails a lack of relaxation of the upper esophageal sphincter. It is rare in children and its etiology is related to multiple factors. The symptoms are nonspecific and may be masked by other diseases. CLINICAL CASE: Report two infants with dysphagia and choking episodes. Upper gastrointestinal series confirmed cricopharyngeal achalasia. The first patient was treated with endoscopic dilatation, and did not require further therapies...
January 15, 2016: Cirugía Pediátrica: Organo Oficial de la Sociedad Española de Cirugía Pediátrica
Ying-Feng Hsu, Yu-Hsun Chen, Chih-Wei Chang
We performed comprehensive studies on the photoluminescence properties of the carbon dots prepared from citric acid (C-dots(CA)) and citric acid + ethylenediamine (C-dots(CA+EDA)). The cryogenic experiment confirmed that the excitation dependent fluorescence and the spectral relaxation dynamics of the C-dots are associated with the presence of multiple emissive states/species in the C-dots instead of solvation dynamics. Moreover, we also compared the size of the C-dots estimated from the TEM/AFM images and fluorescence anisotropy methods...
October 24, 2016: Physical Chemistry Chemical Physics: PCCP
Ibrahim J Domian, Hanry Yu, Nikhil Mittal
In this essay the authors argue that chamber pressure dominates the biomechanics of the contraction cycle of the heart, while tissue stiffness dominates the relaxation cycle. This appears to be an under-recognized challenge in cardiac tissue engineering. Optimal approaches will involve constructing chambers or modulating the stiffness of the scaffold/substrate in synchrony with the beating cycle.
October 24, 2016: Advanced Healthcare Materials
Filip Bielejec, Guy Baele, Allen G Rodrigo, Marc A Suchard, Philippe Lemey
Various factors determine the rate at which mutations are generated and fixed in viral genomes. Viral evolutionary rates may vary over the course of a single persistent infection and can reflect changes in replication rates and selective dynamics. Dedicated statistical inference approaches are required to understand how the complex interplay of these processes shapes the genetic diversity and divergence in viral populations. Although evolutionary models accommodating a high degree of complexity can now be formalized, adequately informing these models by potentially sparse data, and assessing the association of the resulting estimates with external predictors, remains a major challenge...
July 2016: Virus Evolution
Ganna Gryn'ova, Michelle L Coote, Clemence Corminboeuf
The electronic configuration of the molecule is the foundation of its structure and reactivity. The spin state is one of the key characteristics arising from the ordering of electrons within the molecule's set of orbitals. Organic molecules that have open-shell ground states and interesting physicochemical properties, particularly those influencing their spin alignment, are of immense interest within the up-and-coming field of molecular electronics. In this advanced review, we scrutinize various qualitative rules of orbital occupation and spin alignment, viz...
November 2015: Wiley Interdisciplinary Reviews. Computational Molecular Science
S Vijayachitra, K Sasikala
Research in combinatorics on words goes back a century. Berstel and Boasson introduced the partial words in the context of gene comparison. Alignment of two genes can be viewed as a construction of two partial words that are said to be compatible. In this paper, we examine to which extent the fundamental properties of partial words such as compatbility and conjugacy remain true for partial arrays. This paper studies a relaxation of the compatibility relation called k-compability. It also studies k-conjugacy of partial arrays...
2016: Computational and Mathematical Methods in Medicine
Natalie E Taylor, Sarah E Baker, Thomas P Olson, Sophie Lalande, Bruce D Johnson, Eric M Snyder
BACKGROUND: Beta-2 adrenergic receptors (β2ARs) are located throughout the body including airway and alveolar cells. The β2ARs regulate lung fluid clearance through a variety of mechanisms including ion transport on alveolar cells and relaxation of the pulmonary lymphatics. We examined the effect of an inhaled β2-agonist (albuterol) on alveolar-capillary membrane conductance (DM) and pulmonary capillary blood volume (VC) in healthy humans. METHODS: We assessed the diffusing capacity of the lungs for carbon monoxide (DLCO) and nitric oxide (DLNO) at baseline, 30 minutes, and 60 minutes following nebulized albuterol (2...
2016: Clinical Medicine Insights. Circulatory, Respiratory and Pulmonary Medicine
Lijing Xin, Ivan Tkáč
Localized proton magnetic resonance spectroscopy ((1)H-MRS) is a noninvasive tool for measuring in vivo neurochemical information in animal and human brains. With the increase of magnetic field strength, whereas localized (1)H-MRS benefits from higher sensitivity and spectral dispersion, it is challenged by increased spatial inhomogeneity of the B0 and B1 fields, larger chemical shift displacement error, and shortened T2 relaxation times of metabolites. Advanced localized (1)H-MRS methodologies developed for high magnetic fields have shown promising results and allow the measurement of neurochemical profiles with up to 19 brain metabolites, including less-abundant metabolites, such as glutathione, glycine, γ-aminobutyric acid and ascorbate...
October 20, 2016: Analytical Biochemistry
M Teresa Viciosa, Joaquim J Moura Ramos, Hermínio P Diogo
The slow molecular mobility in the amorphous solid state of 3 active pharmaceutical drugs (cimetidine, nizatidine, and famotidine) has been studied using differential scanning calorimetry and the 2 dielectric-related techniques of dielectric relaxation spectroscopy and thermally stimulated depolarization currents. The glass-forming ability, the glass stability, and the tendency for crystallization from the equilibrium melt were investigated by differential scanning calorimetry, which also provided the characterization of the main relaxation of the 3 glass formers...
October 20, 2016: Journal of Pharmaceutical Sciences
Qing Wang, Donglan Zhang, Zhiyuan Hou
The private health care sector has become an increasingly important complement to China's health care system. During the health care reform in 2009, China's central government established multiple initiatives to relax constraints on the growth of the private health care sector. However, private health services have not been growing as rapidly as private health care facilities. Using data from the China Health and Retirement Longitudinal Study collected between 2011 and 2013, this study investigated patient choice between private and public providers for outpatient care and estimated its relationship with health insurance and socioeconomic status (SES)...
October 18, 2016: Social Science & Medicine
Seyyed Shamsadin Athari, Zahra Pourpak, Gert Folkerts, Johan Garssen, Mostafa Moin, Ian M Adcock, Masoud Movassaghi, Mehdi Shafiee Ardestani, Seyed Mohammad Moazzeni, Esmaeil Mortaz
Asthma is a chronic respiratory disease characterized by airway inflammation, bronchoconstriction, airway hyperresponsiveness and recurring attacks of impaired breathing. Vasoactive intestinal peptide (VIP) has been proposed as a novel anti-asthma drug due to its effects on airway smooth muscle relaxation, bronchodilation and vasodilation along with its immunomodulatory and anti-inflammatory properties. In the current study, we investigated the therapeutic effects of VIP when conjugated with α-alumina nanoparticle (α-AN) to prevent enzymatic degradation of VIP in the respiratory tract...
October 19, 2016: European Journal of Pharmacology
Takeshi Kinoshita, Masashi Tawa, Tomoaki Suzuki, Yoshinari Aimi, Tohru Asai, Tomio Okamura
OBJECTIVES: The present study was designed to evaluate the association between chronic kidney disease and the endothelial function of internal thoracic artery (ITA) grafts in patients undergoing coronary bypass surgery. An isometric tension study was performed in ITA strips obtained during surgery. Concentration-response curves for acetylcholine (ACh) and sodium nitroprusside were constructed in ITA strips partially precontracted with phenylephrine under the inhibition of cyclooxygenase...
September 23, 2016: Journal of Thoracic and Cardiovascular Surgery
Yinping Huang, Kaili Mao, Baolin Zhang, Yingzheng Zhao
Monodispersed SPIONs (superparamagnetic iron oxide nanoparticles) co-coated with PEG and PEI polymers were prepared by an improved polyol method. To accomplish cancer-specific targeting properties, FA (folic acid) was then modified on the SPIONs via EDC/NHS method (FA-SPIONs). Doxorubicin (DOX) as an example anticancer drug was loaded within FA-SPIONs (DOX@FA-SPIONs), the DOX release rate of DOX@FA-SPIONs was much high in low pH PBS. The SPIONs, FA-SPIONs and DOX@FA-SPIONs with mean hydrodynamic diameters of 23, 40 and 67nm, respectively, performed excellent colloidal stability in PBS...
January 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
Luke Burke, Chris J Mortimer, Daniel J Curtis, Aled R Lewis, Rhodri Williams, Karl Hawkins, Thierry G G Maffeis, Chris J Wright
We demonstrate a facile, one-step process to form polymer scaffolds composed of magnetic iron oxide nanoparticles (MNPs) contained within electrospun nano- and micro-fibres of two biocompatible polymers, Poly(ethylene oxide) (PEO) and Poly(vinyl pyrrolidone) (PVP). This was achieved with both needle and free-surface electrospinning systems demonstrating the scalability of the composite fibre manufacture; a 228 fold increase in fibre fabrication was observed for the free-surface system. In all cases the nanoparticle-nanofibre composite scaffolds displayed morphological properties as good as or better than those previously described and fabricated using complex multi-stage techniques...
January 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
Melanie L Bell, Diane L Fairclough, Mallorie H Fiero, Phyllis N Butow
BACKGROUND: The Hospital Anxiety and Depression Scale (HADS) is a widely used questionnaire in health research, but there is little guidance on how to handle missing items. We aimed to investigate approaches to handling item non-response, varying sample size, proportion of subjects with missing items, proportion of missing items per subject, and the missingness mechanism. METHODS: We performed a simulation study based on anxiety and depression data among cancer survivors and patients...
October 22, 2016: BMC Research Notes
Andreas Keil, Sean R Hall, Meike Körner, Martin Herrmann, Ralph A Schmid, Steffen Frese
BACKGROUND: Since the precise mechanism for the pathogenesis of systemic lupus erythematosus (SLE) is unknown, no targeted therapies in addition to immunosuppression are available so far. We recently demonstrated that administration of the topoisomerase I (topo I) inhibitor irinotecan at extremely low concentrations reversed established lupus nephritis in NZB/NZW mice. While profound immunosuppression was absent, we proposed changes in DNA relaxation and anti-double-stranded (ds)DNA antibody binding as the underlying mechanism...
October 22, 2016: Arthritis Research & Therapy
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