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https://www.readbyqxmd.com/read/28944060/one-ion-to-rule-them-all-combined-antibacterial-osteoinductive-and-anticancer-properties-of-selenite-incorporated-hydroxyapatite
#1
Vuk Uskoković, Maheshwar Adiraj Iyer, Victoria M Wu
Although hydroxyapatite (HAp) has been doped with dozens of different ions, the quest for an ion imparting a combination of properties conducive to bone healing is still ongoing. Because of its protean potency and the similarity in size and shape to the phosphate tetrahedron, selenite ion presents a natural ionic substitute in HAp. The incorporation of selenite into synthetic HAp using two different methods - co-precipitation and ion-exchange sorption - was studied for its effect on crystal properties and on a triad of biological responses: antibacterial, anticancer and osteoinductive...
2017: Journal of Materials Chemistry. B, Materials for Biology and Medicine
https://www.readbyqxmd.com/read/28944003/partial-fusion-of-a-cytochrome-p450-system-by-carboxy-terminal-attachment-of-putidaredoxin-reductase-to-p450cam-cyp101a1
#2
Eachan O Johnson, Luet-Lok Wong
Cytochrome P450 (CYP) enzymes catalyze the insertion of oxygen into carbon-hydrogen bonds and have great potential for enzymatic synthesis. Application development of class I CYPs is hampered by their dependence on two redox partners (a ferredoxin and ferredoxin reductase), slowing catalysis compared to self-sufficient CYPs such as CYP102A1 (P450BM3). Previous attempts to address this have fused all three components in several permutations and geometries, with much reduced activity compared to the native system...
October 21, 2016: Catalysis Science & Technology
https://www.readbyqxmd.com/read/28943226/influences-of-red-blood-cell-and-platelet-counts-on-the-distribution-and-elimination-of-crystalloid-fluid
#3
Robert G Hahn
BACKGROUND AND OBJECTIVE: A high number of blood cells increases the viscosity of the blood. The present study explored whether variations in blood cell counts are relevant to the distribution and elimination of infused crystalloid fluid. MATERIALS AND METHODS: On three different occasions, 10 healthy male volunteers received an intravenous infusion of 25mL/kg of Ringer's acetate, Ringer's lactate, and isotonic saline over 30min. Blood hemoglobin and urinary excretion were monitored for 4h and used as input in a two-volume kinetic model, using nonlinear mixed effects software...
August 3, 2017: Medicina
https://www.readbyqxmd.com/read/28941459/loss-of-melanin-by-eye-retinal-pigment-epithelium-cells-is-associated-with-its-oxidative-destruction-in-melanolipofuscin-granules
#4
A E Dontsov, N L Sakina, M A Ostrovsky
The effect of superoxide radicals on melanin destruction and degradation of melanosomes isolated from cells of retinal pigment epithelium (RPE) of the human eye was studied. We found that potassium superoxide causes destruction of melanin in melanosomes of human and bovine RPE, as well as destruction of melanin from the ink bag of squid, with the formation of fluorescent decay products having an emission maximum at 520-525 nm. The initial kinetics of the accumulation of the fluorescent decay products is linear...
August 2017: Biochemistry. Biokhimii︠a︡
https://www.readbyqxmd.com/read/28939886/apicomplexan-actin-polymerization-depends-on-nucleation
#5
Esa-Pekka Kumpula, Isa Pires, Devaki Lasiwa, Henni Piirainen, Ulrich Bergmann, Juha Vahokoski, Inari Kursula
Filamentous actin is critical for apicomplexan motility and host cell invasion. Yet, parasite actin filaments are short and unstable. Their kinetic characterization has been hampered by the lack of robust quantitative methods. Using a modified labeling method, we carried out thorough biochemical characterization of malaria parasite actin. In contrast to the isodesmic polymerization mechanism suggested for Toxoplasma gondii actin, Plasmodium falciparum actin I polymerizes via the classical nucleation-elongation pathway, with kinetics similar to canonical actins...
September 22, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28934658/changes-in-activation-energy-and-kinetics-of-heat-activated-persulfate-oxidation-of-phenol-in-response-to-changes-in-ph-and-temperature
#6
Jie Ma, Haiyan Li, Liping Chi, Hongkun Chen, Changzhao Chen
Persulfate (peroxydisulfate, S2O8(2-)) is the newest oxidant used for the in situ chemical oxidation (ISCO) remediation of soil and groundwater. The present study investigated impacts of solution pH, temperature, and persulfate concentration on the reaction rate constant (k1), activation energy (Ea), and reaction order of the heat-activated persulfate process. Phenol was chosen as the model organic contaminant. As temperature increased from 30 °C to 70 °C, k1 exhibited a significant increase from 0.003 h(-1)∼0...
September 13, 2017: Chemosphere
https://www.readbyqxmd.com/read/28934415/first-report-of-urease-activity-in-the-novel-systemic-fungal-pathogen-emergomyces-africanus-a-comparison-with-the-neurotrope-cryptococcus-neoformans
#7
Barbra Lerm, Chris Kenyon, Ilan S Schwartz, Heinrich Kroukamp, Riaan de Witt, Nelesh P Govender, G Sybren de Hoog, Alfred Botha
Cryptococcus neoformans is an opportunistic pathogen responsible for the AIDS-defining illness, cryptococcal meningitis. During the disease process, entry of cryptococcal cells into the brain is facilitated by virulence factors that include urease enzyme activity. A novel species of an Emmonsia-like fungus, recently named Emergomyces africanus, was identified as a cause of disseminated mycosis in HIV-infected persons in South Africa. However, in contrast to C. neoformans, the enzymes produced by this fungus, some of which may be involved in pathogenesis, have not been described...
November 1, 2017: FEMS Yeast Research
https://www.readbyqxmd.com/read/28933825/the-surface-chemistry-of-perovskite-type-electrodes-during-high-temperature-co2-electrolysis-investigated-by-operando-photoelectron-spectroscopy
#8
Alexander Karl Opitz, Andreas Nenning, Christoph Rameshan, Markus Kubicek, Thomas Götsch, Raoul Blume, Michael Hävecker, Axel Knop-Gericke, Gunther Rupprechter, Bernhard Klötzer, Juergen Fleig
Any substantial move of energy sources from fossil fuels to renewable resources requires large scale storage of excess energy, for example via power to fuel processes. In this respect electrochemical reduction of CO2 may become very important, since it offers a method of sustainable CO production, which is a crucial prerequisite for synthesis of sustainable fuels. Carbon dioxide reduction in solid oxide electrolysis cells (SOECs) is particularly promising owing to the high operating temperature, which leads to both improved thermodynamics and fast kinetics...
September 21, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28933494/catalyst-free-room-temperature-iclick-reaction-of-molybdenum-ii-and-tungsten-ii-azide-complexes-with-electron-poor-alkynes-structural-preferences-and-kinetic-studies
#9
Paul Schmid, Matthias Maier, Hendrik Pfeiffer, Anja Belz, Lucas Henry, Alexandra Friedrich, Fabian Schönfeld, Katharina Edkins, Ulrich Schatzschneider
Two isostructural and isoelectronic group VI azide complexes of the general formula [M(η(3)-allyl)(N3)(bpy)(CO)2] with M = Mo, W and bpy = 2,2'-bipyridine were prepared and fully characterized, including X-ray structure analysis. Both reacted smoothly with electron-poor alkynes such as dimethyl acetylenedicarboxylate (DMAD) and 4,4,4-trifluoro-2-butynoic acid ethyl ester in a catalyst-free room-temperature iClick [3 + 2] cycloaddition reaction. Reaction with phenyl(trifluoromethyl)acetylene, on the other hand, did not lead to any product formation...
September 21, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28931538/modulators-of-actin-myosin-dissociation-basis-for-muscle-type-functional-differences-during-fatigue
#10
Christina Karatzaferi, Nancy Adamek, Michael A Geeves
The muscle types present with variable fatigue tolerance, in part due to the myosin isoform expressed. However, the critical steps that define 'fatigability' in vivo of fast vs slow myosin isoforms, at the molecular level, are not yet fully understood. We examined the modulation of the ATP-induced myosin sub-fragment 1 (S1) dissociation from pyrene-actin by inorganic phosphate (Pi), pH and temperature using a specially modified stopped-flow system that allowed fast kinetics measurements at physiological temperature...
September 20, 2017: American Journal of Physiology. Cell Physiology
https://www.readbyqxmd.com/read/28929243/discrimination-between-benign-and-malignant-breast-lesions-using-volumetric-quantitative-dynamic-contrast-enhanced-mr-imaging
#11
Ziliang Cheng, Zhuo Wu, Guangzi Shi, Zhilong Yi, Mingwei Xie, Weike Zeng, Chao Song, Chushan Zheng, Jun Shen
OBJECTIVE: To determine the diagnostic performance of volumetric quantitative dynamic contrast-enhanced MRI (qDCE-MRI) in differentiation between malignant and benign breast lesions. METHODS: DCE-MRI was performed in 124 patients with 136 breast lesions. Quantitative pharmacokinetic parameters K(trans), Kep, Ve, Vp and semi-quantitative parameters TTP, MaxCon, MaxSlope, AUC were obtained by using a two-compartment extended Tofts model and three-dimensional volume of interest...
September 19, 2017: European Radiology
https://www.readbyqxmd.com/read/28927239/tubulins-rhythms-and-cell-walls-in-poplar-leaves-it-s-all-in-the-timing
#12
Scott A Harding, Hao Hu, Batbayar Nyamdari, Liang-Jiao Xue, Radnaa Naran, Chung-Jui Tsai
Plant cell walls exhibit architectural and compositional changes throughout their development and in response to external cues. While tubulins are involved in cell wall biogenesis, much remains unknown about the scope of their involvement during the orchestration of this resource-demanding process. A transgenic approach coupled with cell wall compositional analysis, RNA-seq and mining of publicly available diurnal gene expression data was used to assess the involvement of tubulins in poplar leaf cell wall biogenesis...
September 12, 2017: Tree Physiology
https://www.readbyqxmd.com/read/28923880/impact-of-liver-fat-on-the-differential-partitioning-of-hepatic-triacylglycerol-into-vldl-subclasses-on-high-and-low-sugar-diets
#13
A Margot Umpleby, Fariba Shojaee-Moradie, Barbara Fielding, Xuefei Li, Andrea Marino, Najlaa Alsini, Cheryl Isherwood, Nicola Jackson, Aryati Ahmad, Michael Stolinski, Julie Anne Lovegrove, Sigurd Johnsen, Jeewaka Mendis, John Wright, Malgorzata E Wilinska, Roman Hovorka, Jimmy Bell, Louise E Thomas, Gary Frost, Bruce Arthur Griffin
Dietary sugars are linked to the development of non-alcoholic fatty liver disease (NAFLD) and dyslipidaemia, but it is unknown if NAFLD itself influences the effects of sugars on plasma lipoproteins. To study this further, men with NAFLD (n=11) and low liver fat 'controls' (n= 14) were fed two iso-energetic diets, high or low in sugars (26% or 6% total energy) for 12 weeks, in a randomised, cross-over design. Fasting plasma lipid and lipoprotein kinetics were measured after each diet by stable isotope trace-labelling...
September 18, 2017: Clinical Science (1979-)
https://www.readbyqxmd.com/read/28921052/in-vitro-evaluation-of-flow-patterns-and-turbulent-kinetic-energy-in-trans-catheter-aortic-valve-prostheses
#14
Daniel Giese, Kilian Weiss, Bettina Baeßler, Navid Madershahian, Yeong-Hoon Choi, David Maintz, Alexander C Bunck
OBJECTIVES: The objective of the current work was to evaluate flow and turbulent kinetic energy in different transcatheter aortic valve implants using highly undersampled time-resolved multi-point 3-directional phase-contrast measurements (4D Flow MRI) in an in vitro setup. MATERIALS AND METHODS: A pulsatile flow setup was used with a compliant tubing mimicking a stiff left ventricular outflow tract and ascending aorta. Five different implants were measured using a highly undersampled multi-point 4D Flow MRI sequence...
September 18, 2017: Magma
https://www.readbyqxmd.com/read/28919234/effects-of-periplasmic-chaperones-and-membrane-thickness-on-bama-catalysed-outer-membrane-protein-folding
#15
Bob Schiffrin, Antonio N Calabrese, Anna J Higgins, Julia R Humes, Alison E Ashcroft, Antreas C Kalli, David J Brockwell, Sheena E Radford
The biogenesis of outer membrane proteins (OMPs) in Gram-negative bacteria involves delivery by periplasmic chaperones to the β-barrel assembly machinery (BAM) which catalyses OMP insertion into the outer membrane (OM). Here, we examine the effects of membrane thickness, the E. coli periplasmic chaperones Skp and SurA, and BamA, the central subunit of the BAM complex, on the folding kinetics of a model OMP (tOmpA) using fluorescence spectroscopy, native mass spectrometry, and molecular dynamics (MD) simulations...
September 15, 2017: Journal of Molecular Biology
https://www.readbyqxmd.com/read/28915413/transmission-electron-microscopy-studies-and-modeling-of-3d-reciprocal-space-of-%C3%AF-forming-alloy
#16
Alphy George, Vinayak Sharma, R Divakar, M Sabeena, E Mohandas
Initial stage of ω phase formation and associated anomalous features that appear in diffraction patterns of a metastable β transition metal alloy have been investigated in this study with the aid of transmission electron microscopy, simulation and modeling. The paper explores discrete features that emerge in selected area diffraction patterns of quenched Ti-15wt%Mo alloy and analyzes the correlation between ω reflections and diffuse arcs by considering all variants of ω phase as per the formation kinetics of ω phase in β matrix while quenching...
September 12, 2017: Micron: the International Research and Review Journal for Microscopy
https://www.readbyqxmd.com/read/28914528/inhibition-of-human-and-rat-sucrase-and-maltase-activities-to-assess-anti-glycemic-potential-optimisation-of-the-assay-using-acarbose-and-polyphenols
#17
Alison Pyner, Hilda Nyambe-Silavwe, Gary Williamson
We have optimised the assays used to measure inhibition of rat and human α-glucosidases (sucrase and maltase activities), intestinal enzymes which catalyse the final steps of carbohydrate digestion. Cell-free extracts from fully differentiated intestinal Caco-2/TC7 monolayers were shown to be a suitable source of sucrase-isomaltase, with the same sequence as human small intestine, and were compared to a rat intestinal extract. The kinetic conditions of the assay were optimised, including comparison of enzymatic and chromatographic methods to detect the monosaccharide products...
September 15, 2017: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/28914463/burrowing-with-a-kinetic-snout-in-a-snake-elapidae-aspidelaps-scutatus
#18
Alexandra Deufel
Of the few elongate, fossorial vertebrates that have been examined for their burrowing mechanics, all were found to use an akinetic, reinforced skull to push into the soil, powered mostly by trunk muscles. Reinforced skulls were considered essential for head-first burrowing. In contrast, I found that the skull of the fossorial shield-nosed cobra (Aspidelaps scutatus) is not reinforced and retains the kinetic potential typical of many non-fossorial snakes. Aspidelaps scutatus burrows using a greatly enlarged rostral scale that is attached to a kinetic snout that is independently mobile with respect to the rest of the skull...
September 15, 2017: Journal of Morphology
https://www.readbyqxmd.com/read/28913831/asymmetry-between-on-and-off-alpha-ganglion-cells-of-mouse-retina-integration-of-signal-and-noise-from-synaptic-inputs
#19
Michael A Freed
ON and OFF pathways in the retina include functional pairs of neurons that, at first glance, appear to have symmetrically similar responses to brightening and darkening, respectively. Upon careful examination, however, functional pairs exhibit asymmetries in receptive field size and response kinetics. Until now, descriptions of how light-adapted retinal circuitry maintains a preponderance of signal over the noise have not distinguished between ON and OFF pathways. Here I present evidence of marked asymmetries between members of a functional pair of sustained alpha ganglion cells in the mouse retina...
September 15, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/28912893/the-role-of-nitric-oxide-during-sonoreperfusion-of-microvascular-obstruction
#20
Francois T H Yu, Xucai Chen, Adam C Straub, John J Pacella
Rationale: Microembolization during PCI for acute myocardial infarction can cause microvascular obstruction (MVO). MVO severely limits the success of reperfusion therapies, is associated with additional myonecrosis, and is linked to worse prognosis, including death. We have shown, both in in vitro and in vivo models, that ultrasound (US) and microbubble (MB) therapy (termed "sonoreperfusion" or "SRP") is a theranostic approach that relieves MVO and restores perfusion, but the underlying mechanisms remain to be established...
2017: Theranostics
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