Read by QxMD icon Read

Subtle energies

Lee-Jin Bong, Wu-Chun Tu, Kok-Boon Neoh, Chin-Gi Huang, Rou-Xing Ting
The phenomenon of high egg reproduction when mortality risk rises is common in mosquitoes. However, the phenomenon may vary between insecticide susceptible and field-collected strains, due to the latter's decreased energy allocation in reproduction in the presence of insecticide resistance. In this study, we evaluated the effect of chlorpyrifos (CP) and temephos (TP) exposure on the oviposition and survival of Aedes aegypti (Linnaeus) (Diptera: Culicidae) using a susceptible strain (KHsm) and two field strains (KHly and TNnorth)...
October 10, 2017: Journal of Medical Entomology
Vera Beermann, Martin Gocyla, Stefanier Kuehl, Elliot Padgett, Henrike Schmies, Mikaela Goerlin, Nina Erini, Meital Shviro, Marc Heggen, Rafal E Dunin-Borkowski, David Muller, Peter Strasser
Shape-controlled octahedral Pt-Ni alloy nanoparticles exhibit remarkably high activities for the electroreduction of molecular oxygen (ORR), which makes them fuel cell cathode catalysts with exceptional potential. To unfold their full and optimized catalytic activity and stability, however, the nano-octahedra require post-synthesis thermal treatments, which alter the surface atomic structure and composition of the crystal facets. Here, we address and strive to elucidate the underlying surface chemical processes using a combination of ex situ analytical techniques with in situ transmission electron microscopy (TEM), in situ x-ray diffraction (XRD), and in situ electrochemical Fourier transformed infra-red (FTIR) experiments...
October 11, 2017: Journal of the American Chemical Society
C Collazos, C Lopera, J E P Santos, J Laporta
The objectives were to investigate the effects that maternal diets containing negative dietary cation-anion differences (DCAD) fed in the last 42 d of gestation may have on the acid-base status, hematology, mineral and energy metabolism, growth, and health of calves. The experiment was a randomized block design with a 2 × 2 factorial arrangement of 2 levels of negative DCAD (-70 or -180 mEq/kg) and 2 feeding durations (the last 21 d prepartum and the last 42 d prepartum). Bulls and heifers (n = 60) born to these dams were weighted at birth and fed 3...
October 4, 2017: Journal of Dairy Science
Asiloé J Mora, Lusbely M Belandria, Gerzon E Delgado, Luis E Seijas, Angel Lunar, Rafael Almeida
Single-crystal X-ray diffraction and quantum mechanical theories were used to examine in detail the subtle nature of non-covalent interactions in the [2:1:1] multicomponent crystal of 1,1-aminocyclopentanecarboxylic acid:oxalic acid:water. The crystal, which is a hydrate salt of the amino acid with the hydrogen-oxalate ion, also contains the zwitterion of the amino acid in equal proportions. It was found that a dimeric cation [Acc5(Z)...Acc5(C)](+) bonded by an O-H...O hydrogen bond exists due to a charge transfer between acid and carboxylate groups...
October 1, 2017: Acta Crystallographica Section B, Structural Science, Crystal Engineering and Materials
Jiayi Dou, Lindsey Doyle, Per Jr Greisen, Alberto Schena, Hahnbeom Park, Kai Johnsson, Barry L Stoddard, David Baker
The steroid hormone 17α-hydroxylprogesterone (17-OHP) is a biomarker for congenital adrenal hyperplasia and hence there is considerable interest in sensor development towards this compound. We used computational protein design to generate protein models with binding sites for 17-OHP containing an extended, nonpolar, shape-complementary binding pocket corresponding to the four-ring core of the compound, and hydrogen bonding residues at the base of the pocket to interact with carbonyl and hydroxyl groups at the more polar end of the ligand...
October 4, 2017: Protein Science: a Publication of the Protein Society
Silvia Nicotra, Daniela Sorio, Giulia Filippi, Luca De Gioia, Veronica Paterlini, Elio Franco De Palo, Rita Grandori, Franco Tagliaro, Carlo Santambrogio
Transferrin (Tf) is the major iron-transporting protein in the human body and, for this reason, has been extensively studied in biomedicine. This protein undergoes a complex glycosylation process leading to several glycoforms, some of which are important in the diagnosis of alcohol abuse and of congenital glycosylation defects under the collective name of carbohydrate-deficient transferrin (CDT). Exploiting the Tf ability to bind not only iron but also other ions, specific attention has been devoted to binding activity towards Tb(3+), which was reported to greatly enhance its intrinsic fluorescence upon the interaction with Tf...
September 29, 2017: Analytical and Bioanalytical Chemistry
Jevgenij A Raskatov, David B Teplow
Intrinsically disordered protein (IDP) conformers occupy large regions of conformational space and display relatively flat energy surfaces. Amyloid-forming IDPs, unlike natively folded proteins, have folding trajectories that frequently involve movements up shallow energy gradients prior to the "downhill" folding leading to fibril formation. We suggest that structural perturbations caused by chiral inversions of amino acid side-chains may be especially valuable in elucidating these pathways of IDP folding. Chiral inversions are subtle in that they do not change side-chain size, flexibility, hydropathy, charge, or polarizability...
October 2, 2017: Scientific Reports
Gabriel Heerdt, Ionut Tranca, Albert J Markvoort, Bartłomiej M Szyja, Nelson H Morgon, Emiel J M Hensen
HYPOTHESIS: In photorheological fluids, subtle molecular changes caused by light lead to abrupt macroscopic alterations. Upon UV irradiation of an aqueous cetyltrimethylammonium bromide (CTAB) and trans-ortho-methoxycinnamic acid (trans-OMCA) solution, for instance, the viscosity drops over orders of magnitude. Multiscale modeling allows to elucidate the mechanisms behind these photorheological effects. EXPERIMENTS: We use time-dependent DFT calculations to study the photoisomerization, and a combination of atomistic molecular dynamics (MD) and DFT to probe the influence of both OMCA isomers on the micellar solutions...
September 12, 2017: Journal of Colloid and Interface Science
Maja A Dunstan, Elodie Rousset, Marie-Emmanuelle Boulon, Robert W Gable, Lorenzo Sorace, Colette Boskovic
Three families of tetraoxolene-bridged dinuclear rare earth (RE) complexes have been synthesised and characterised, with general formula [((HB(pz)3)2RE)2(μ-tetraoxolene)] (HB(pz)3(-) = hydrotris(pyrazolyl)borate; tetraoxolene = chloranilate (1-RE), the dianionic form of 2,5-dihydroxy-1,4-benzoquinone (2-RE), or its 3,6-dimethyl analogue (3-RE)). In each case, the bridging tetraoxolene ligand is in the diamagnetic dianionic form and species with selected lanthanoid(iii) ions from Eu(iii) to Yb(iii) have been obtained, as well as the diamagnetic Y(iii) analogues...
October 17, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Christophe Raufaste, Gabriela Ramos Chagas, Thierry Darmanin, Cyrille Claudet, Frédéric Guittard, Franck Celestini
We investigate the behavior of droplets and soft elastic objects propelled with a catapult. Experiments show that the ejection velocity depends on both the projectile deformation and the catapult acceleration dynamics. With a subtle matching given by a peculiar value of the projectile/catapult frequency ratio, a 250% kinetic energy gain is obtained as compared to the propulsion of a rigid projectile with the same engine. This superpropulsion has strong potentialities: actuation of droplets, sorting of objects according to their elastic properties, and energy saving for propulsion engines...
September 8, 2017: Physical Review Letters
Rami M A Al-Dirini
For cementless femoral stems, there is debate as to whether a collar enhances primary stability and load transfer compared to collarless designs. Finite Element (FE) analysis has the potential to compare stem designs within the same cohort, allowing for subtle performance differences to be identified, if present. Subject-specific FE models of intact and implanted femora were run for a diverse cohort (21 males, 20 females; BMI 16.4-41.2 kg.m(-2) , age 50-80yrs). Collared and collarless versions of Corail® (DePuy Synthes) were sized and positioned using an automated algorithm that aligns the femoral/stem axes, preserves the head-centre location and maximises metaphyseal fit...
September 21, 2017: Journal of Orthopaedic Research: Official Publication of the Orthopaedic Research Society
Elizabeth George, Jeremy R Wortman, Urvi P Fulwadhva, Jennifer W Uyeda, Aaron D Sodickson
Dual energy CT is a technology that is gaining widespread acceptance, particularly for its abdominopelvic applications. Pancreatic pathologies are an ideal application for the many advantages offered by dual energy post-processing. This article reviews the current literature on dual energy CT pancreatic imaging, specifically in the evaluation of pancreatic adenocarcinoma, other solid and cystic pancreatic neoplasms, and pancreatitis. The advantages in characterization and quantification of enhancement, detection of subtle lesions, and potential reduction of imaging phases and contrast usage are reviewed...
September 22, 2017: British Journal of Radiology
Xinyue Song, Jiayu Zhang, Zihong Yue, Zonghua Wang, Zhihong Liu, Shusheng Zhang
Monitoring the fluctuation of hydroxyl radical (·OH) in the body can serve as an effective tool for the prediction of relative diseases; however, it is highly challenging due to the radical's short lifetime, high reactivity, and extremely low concentration. Sandwich structured lanthanide-doped upconversion nanoparticles (UCNPs) exhibit unique luminescence properties and great prospects in bioimaging. Nonetheless, their rather low luminescence efficiency and intensity are serious limitations for their application...
October 17, 2017: Analytical Chemistry
Ravi R Sonani, Aleksander W Roszak, Claire Ortmann de Percin Northumberland, Datta Madamwar, Richard J Cogdell
C-Phycoerythrin (PE) from Phormidium sp. A09DM has been crystallized using different conditions and its structure determined to atomic resolution (1.14 Å). In order for the pigment present, phycoerythrobilin (PEB), to function as an efficient light-harvesting molecule it must be held rigidly (Kupka and Scheer in Biochim Biophys Acta 1777:94-103, 2008) and, moreover, the different PEB molecules in PE must be arranged, relative to each other, so as to promote efficient energy transfer between them. This improved structure has allowed us to define in great detail the structure of the PEBs and their binding sites...
September 16, 2017: Photosynthesis Research
Jeremy D Eekhoff, Fei Fang, Lindsey G Kahan, Gabriela Espinosa, Austin J Cocciolone, Jessica E Wagenseil, Robert P Mecham, Spencer P Lake
Elastic fibers are present in low quantities in tendon, where they are located both within fascicles near tenocytes and more broadly in the interfascicular matrix (IFM). While elastic fibers have long been known to be significant in the mechanics of elastin-rich tissue (i.e., vasculature, skin, lungs), recent studies have suggested a mechanical role for elastic fibers in tendons that is dependent on specific tendon function. However, the exact contribution of elastin to properties of different types of tendons (e...
November 1, 2017: Journal of Biomechanical Engineering
Guo-Jun Zhou, Tian Han, You-Song Ding, Nicholas F Chilton, Yan-Zhen Zheng
A series of diabolo-like nonanuclear {Ln(III) Cu(II)8 } (Ln=Tb, Dy, Ho, Er, Tm, Yb, and Y) clusters were prepared in which the Ln(III) ion is capped by two 8-MC-4 metallacrown ligands to form a nearly ideal square antiprismatic (SAP) coordination geometry with D4d symmetry. Despite the lack of crystallographic symmetry, these molecules engender the lanthanide ions with highly axial mJ states. The axial/equatorial nature of the crystal field in environments close to ideal SAP geometry is very subtle and influenced by the nature of the ligand lone pairs...
September 15, 2017: Chemistry: a European Journal
Christoph A Agten, Stephen Honig, Punam K Saha, Ravinder Regatte, Gregory Chang
Background Bone remodels in response to mechanical loads and osteoporosis results from impaired ability of bone to remodel. Bone microarchitecture analysis provides information on bone quality beyond bone mineral density (BMD). Purpose To compare subchondral bone microarchitecture parameters in the medial and lateral tibia plateau in individuals with and without fragility fractures. Material and Methods Twelve female patients (mean age = 58 ± 15 years; six with and six without previous fragility fractures) were examined with dual-energy X-ray absorptiometry (DXA) and 7-T magnetic resonance imaging (MRI) of the proximal tibia...
January 1, 2017: Acta Radiologica
Carolyn Readmond, Chun Wu
Currently, Vorapaxar is the only recently FDA-approved antiplatelet drug targeting Protease-activated receptor 1 (PAR1). However, a novel antagonist, F16357, has been shown to prevent painful bladder syndrome, also known as interstitial cystitis (IC). Unfortunately, there is no high resolution structure of the F16357-receptor complex, hindering its optimization as a therapeutic agent. In this study, we used docking and molecular dynamic (MD) simulations to investigate the detailed interactions between F16357 and PAR1 at a molecular level...
August 24, 2017: Journal of Molecular Graphics & Modelling
Yahong Li, Yaru Qin, Haifeng Zhang, Hao Sun, Yangdan Pan, Yu Ge, Yiquan Zhang
The utilization of 2-ethoxy-6-(((2-hydroxy-3-methoxy benzyl)imino)methyl)phenol (H2L) as a chelating ligand, in combination with the employment of alcohols (EtOH and MeOH) as auxiliary ligands, in the 4f-metal chemistry afforded two series of dinuclear lanthanide complexes of compositions [Ln2L2(NO3)2 (EtOH)2] (Ln = Sm (1), Eu (2), Gd (3), Tb (4), Dy (5), Ho (6), Er (7)) and [Ln2L2(NO3)2(MeOH)2] (Ln = Sm (8), Eu (9), Gd (10), Tb (11), Dy (12), Ho (13), Er (14)). Complexes 1-7 are isomorphous. The two LnIII ions in 1-7 are doubly bridged by two deprotonated aminophenoxide oxygen atoms of two μ2: η0:η1:η2:η1:η1:η0 L2- ligands...
August 24, 2017: Chemistry, An Asian Journal
Phing-How Lou, Eliana Lucchinetti, Katrina Y Scott, Yiming Huang, Manoj Gandhi, Martin Hersberger, Alexander S Clanachan, Hélène Lemieux, Michael Zaugg
Despite the fact that skeletal muscle insulin resistance is the hallmark of type-2 diabetes mellitus (T2DM), inflexibility in substrate energy metabolism has been observed in other tissues such as liver, adipose tissue, and heart. In the heart, structural and functional changes ultimately lead to diabetic cardiomyopathy. However, little is known about the early biochemical changes that cause cardiac metabolic dysregulation and dysfunction. We used a dietary model of fructose-induced T2DM (10% fructose in drinking water for 6 weeks) to study cardiac fatty acid metabolism in early T2DM and related signaling events in order to better understand mechanisms of disease...
August 2017: Physiological Reports
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"