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https://www.readbyqxmd.com/read/28527187/quantitative-stereological-analysis-of-the-highly-porous-hydroxyapatite-scaffolds-using-x-ray-cm-and-sem
#1
Justyna Zygmuntowicz, Aneta Zima, Joanna Czechowska, Karol Szlazak, Anna Ślosarczyk, Katarzyna Konopka
BACKGROUND: Material properties of the scaffolds as well as their microstructure are vital in determining in vivo cellular response. Three-dimensional (3D), highly porous scaffolds are used in tissue engineering to provide a suitable microenvironment and to support regeneration of bone. Both pore sizes and their architecture, in particular interconnection density, impact functionality of scaffold during its biomedical applications. OBJECTIVE: In this paper a comparative study of the microstructure of highly porous hydroxyapatite scaffolds produced via gelcasting of foamed slurries and replication of polyurethane sponge were carried out...
2017: Bio-medical Materials and Engineering
https://www.readbyqxmd.com/read/28526876/inductive-flash-annealing-of-bulk-metallic-glasses
#2
K Kosiba, S Pauly
We developed a temperature-controlled inductive flash-annealing device, which heats bulk metallic glasses (BMGs) at defined rates of up to 200 K/s to a given temperature. Subsequent instantaneous quenching in water allows preserving the microstructures obtained at various stages of crystallization. One Zr-based and two CuZr-based BMGs were flash-annealed at the onset of crystallization with different heating rates in order to prepare advanced BMG-matrix composites. The highly reproducible composite microstructures contain uniformly dispersed crystals and a narrow crystal size distribution...
May 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28526629/the-ultra-structural-organization-of-the-elastic-network-in-the-intra-and-inter-lamellar-matrix-of-the-intervertebral-disc
#3
J Tavakoli, D M Elliott, J J Costi
The inter-lamellar matrix (ILM) -located between adjacent lamellae of the annulus fibrosus- consists of a complex structure of elastic fibres, while elastic fibers of the intra-lamellar region are aligned predominantly parallel to the collagen fibers. The organization of elastic fibres under low magnification, in both inter- and intra-lamellar regions, was studied by light microscopic analysis of histologically prepared samples; however, little is known about their ultrastructure. An ultrastructural visualization of elastic fibres in the inter-lamellar matrix is crucial for describing their contribution to structural integrity, as well as mechanical properties of the annulus fibrosus...
May 16, 2017: Acta Biomaterialia
https://www.readbyqxmd.com/read/28526515/prenatal-lipopolysaccharide-induces-hypothalamic-dopaminergic-hypoactivity-and-autistic-like-behaviors-repetitive-self-grooming-and-stereotypies
#4
Thiago B Kirsten, Maria M Bernardi
Previous investigations by our group have shown that prenatal exposure to lipopolysaccharide (LPS), which mimics infection by gram-negative bacteria, induces social, cognitive, and communication deficits. For a complete screening of autistic-like behaviors, the objective of this study was to evaluate if our rat model also induces restricted and repetitive stereotyped behaviors. Thus, we studied the self-grooming microstructure. We also studied the neurochemistry of hypothalamus and frontal cortex, which are brain areas related to autism to better understand central mechanisms involved in our model...
May 16, 2017: Behavioural Brain Research
https://www.readbyqxmd.com/read/28526443/mechanical-properties-of-polymer-infiltrated-ceramic-sodium-aluminum-silicate-composites-for-dental-restoration
#5
Bencang Cui, Jing Li, Huining Wang, Yuanhua Lin, Yang Shen, Ming Li, Xuliang Deng, Cewen Nan
OBJECTIVE: To fabricate indirect restorative composites for CAD/CAM applications and evaluate the mechanical properties. METHODS: Polymer-infiltrated-ceramic composites were prepared through infiltrating polymer into partially sintered sodium aluminum silicate ceramic blocks and curing. The corresponding samples were fabricated according to standard ISO-4049 using for mechanical properties measurement. The flexural strength and fracture toughness were measured using a mechanical property testing machine...
May 16, 2017: Journal of Dentistry
https://www.readbyqxmd.com/read/28526197/towards-a-quantitative-indicator-of-feather-disruption-following-the-cleansing-of-oiled-birds
#6
Stephen W Bigger, Lawrence N Ngeh, Peter Dann, John D Orbell
A computer-based imaging method for determining feather microstructure coherency following a cleansing treatment, was developed, calibrated and trialled on Mallard Duck (Anas platyrhyhchos) feathers. The feathers were initially contaminated with a light crude oil and then cleansed by either detergent (Deacon 90) treatment or, alternatively, by magnetic particle technology (MPT) using iron powder. The imaging method provides a single quantitative parameter for the coherence of feather microstructure and the results confirm that MPT treatment imparts less disruption to the feather microstructure than detergent treatment...
May 16, 2017: Marine Pollution Bulletin
https://www.readbyqxmd.com/read/28525683/multilayer-microstructure-of-idiopathic-epiretinal-macular-membranes
#7
Claudio Azzolini, Terenzio Congiu, Simone Donati, Alberto Passi, Petra Basso, Eliana Piantanida, Cesare Mariotti, Francesco Testa, Simona M Caprani, Jennifer Cattaneo, Riccardo Vinciguerra
PURPOSE: To identify the ultramicroscopic structure of idiopathic epiretinal macular membranes (iEMMs) by scanning electron microscopy (SEM). METHODS: We examined 28 iEMMs surgically removed from 28 eyes of 28 patients. All specimens, previously observed at stereomicroscope, were treated with an osmium maceration technique. Fine resolution of iEMMs' 3D architecture and their interaction with the retina were studied using a Philips SEM-FEG XL-30 microscope. RESULTS: The specimens appeared as laminar connective structures partially or completely adherent to the inner limiting membrane (ILM)...
May 19, 2017: European Journal of Ophthalmology
https://www.readbyqxmd.com/read/28524556/the-larmor-frequency-shift-in-magnetically-heterogeneous-media-depends-on-their-mesoscopic-structure
#8
Alexander Ruh, Harald Scherer, Valerij G Kiselev
PURPOSE: Recent studies have addressed the determination of the NMR precession frequency in biological tissues containing magnetic susceptibility differences between cell types. The purpose of this study is to investigate the dependence of the precession frequency on medium microstructure using a simple physical model. THEORY: This dependence is governed by diffusion of NMR-visible molecules in magnetically heterogeneous microenvironments. In the limit of fast diffusion, the precession frequency is determined by the average susceptibility-induced magnetic field, whereas in the limit of slow diffusion it is determined by the average local phase factor of precessing spins...
May 19, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28524375/bioprinted-osteogenic-and-vasculogenic-patterns-for-engineering-3d-bone-tissue
#9
Batzaya Byambaa, Nasim Annabi, Kan Yue, Grissel Trujillo-de Santiago, Mario Moisés Alvarez, Weitao Jia, Mehdi Kazemzadeh-Narbat, Su Ryon Shin, Ali Tamayol, Ali Khademhosseini
Fabricating 3D large-scale bone tissue constructs with functional vasculature has been a particular challenge in engineering tissues suitable for repairing large bone defects. To address this challenge, an extrusion-based direct-writing bioprinting strategy is utilized to fabricate microstructured bone-like tissue constructs containing a perfusable vascular lumen. The bioprinted constructs are used as biomimetic in vitro matrices to co-culture human umbilical vein endothelial cells and bone marrow derived human mesenchymal stem cells in a naturally derived hydrogel...
May 19, 2017: Advanced Healthcare Materials
https://www.readbyqxmd.com/read/28523651/microstructure-and-nanomechanical-properties-of-single-stalks-from-diatom-didymosphenia-geminata-and-their-change-due-to-adsorption-of-selected-metal-ions
#10
Izabela Zgłobicka, Adrian Chlanda, Michał Woźniak, Maciej Łojkowski, Robert Szoszkiewicz, Marta Mazurkiewicz-Pawlicka, Wojciech Święszkowski, Elżbieta Wyroba, Krzysztof J Kurzydłowski
We present topographical and nanomechanical characterization of single Didymosphenia geminata stalks. We compared the samples before and after adsorption of metal ions from fresh water samples. Transmission electron microscopy studies of single stalks cross-sections have shown three distinct layers and an additional thin extra coat on the external layer (called here "EL"). Using scanning electron microscopy and atomic force microscopy (AFM) we found that topography of single stalks after ionic adsorption differs significantly from topography of pristine stalks...
May 18, 2017: Journal of Phycology
https://www.readbyqxmd.com/read/28522866/femtosecond-laser-fabrication-of-anatase-tio2-micro-nanostructures-with-chemical-oxidation-and-annealing
#11
Ting Huang, Jinlong Lu, Xin Zhang, Rongshi Xiao, Wuxiong Yang, Qiang Wu
The fabrication of nanoporous anatase TiO2 on a microstructured Ti base is achieved through an innovative hybrid fabrication method involving femtosecond laser ablation coupled with H2O2 oxidation and annealing. The anatase TiO2 micro-nanostructures have superior photocatalytic degradation of methyl orange due to enhanced light harvesting capacity and surface area. The photodegradation efficiency increases by a maximum of 80% compared to the nanoporous anatase TiO2 fabricated through H2O2 oxidation and annealing only (without femtosecond laser ablation)...
May 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28522820/microstructures-mechanical-behavior-and-strengthening-mechanism-of-tisicn-nanocomposite-films
#12
Wei Li, Ping Liu, Zenghui Xue, Fengcang Ma, Ke Zhang, Xiaohong Chen, Rui Feng, Peter K Liaw
Currently, the arguments have existed in the strengthening mechanism and microstructural model of the nanocomposite film due to lack of the convincible experimental evidences. In this investigation, the quarternary TiSiCN nanocomposite films with the different C and Si contents are synthesized by the reactive-magnetron-sputtering technique. The TiSiCN film is characterized as the nanocomposite structure with the TiN nanocrystallites surrounded by the (Si3N4 + C + CNx) interface phase. When the C/Si content ratio is 2:2, the TiSiCN nanocomposite film is remarkably strengthened with the maximal hardness and elastic modulus of 46...
May 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28522676/midlife-and-late-life-vascular-risk-factors-and-white-matter-microstructural-integrity-the-atherosclerosis-risk-in-communities-neurocognitive-study
#13
Melinda C Power, Jonathan V Tingle, Robert I Reid, Juebin Huang, A Richey Sharrett, Josef Coresh, Michael Griswold, Kejal Kantarci, Clifford R Jack, David Knopman, Rebecca F Gottesman, Thomas H Mosley
BACKGROUND: Diffusion tensor imaging measures of white matter (WM) microstructural integrity appear to provide earlier indication of WM injury than WM hyperintensities; however, risk factors for poor WM microstructural integrity have not been established. Our study quantifies the association between vascular risk factors in midlife and late life with measures of late-life WM microstructural integrity. METHODS AND RESULTS: We used data from 1851 participants in ARIC (Atherosclerosis Risk in Communities Study) who completed 3-T magnetic resonance imaging, including diffusion tensor imaging, as part of the ARIC Neurocognitive Study (ARIC-NCS)...
May 18, 2017: Journal of the American Heart Association
https://www.readbyqxmd.com/read/28522097/sleep-spindle-density-in-narcolepsy
#14
Julie Anja Engelhard Christensen, Miki Nikolic, Mathias Hvidtfelt, Birgitte Rahbek Kornum, Poul Jennum
BACKGROUND: Patients with narcolepsy type 1 (NT1) show alterations in sleep stage transitions, rapid-eye-movement (REM) and non-REM sleep due to the loss of hypocretinergic signaling. However, the sleep microstructure has not yet been evaluated in these patients. We aimed to evaluate whether the sleep spindle (SS) density is altered in patients with NT1 compared to controls and patients with narcolepsy type 2 (NT2). METHODS: All-night polysomnographic recordings from 28 NT1 patients, 19 NT2 patients, 20 controls (C) with narcolepsy-like symptoms, but with normal cerebrospinal fluid hypocretin levels and multiple sleep latency tests, and 18 healthy controls (HC) were included...
June 2017: Sleep Medicine
https://www.readbyqxmd.com/read/28522004/development-of-biocompatible-glycodynameric-hydrogels-joining-two-natural-motifs-by-dynamic-constitutional-chemistry
#15
Luminita Marin, Daniela Ailincai, Simona Morariu, Liliana Tartau-Mititelu
The paper focusses on the synthesis of novel hydrogels by joining natural biodegradable compounds with the aim to achieve biocompatible materials for bio related applications. The hydrogels were prepared from chitosan and citral by constitutional dynamic chemistry, incorporating both molecular and supramolecular dynamic features. The hydrophobic flexible citral has been reversible immobilized onto the hydrophilic chitosan backbone via imine bonds to form amphiphilic glycodynamers, which further self-ordered through supramolecular interactions into a 3D-network of biodynameric hydrogel...
August 15, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28521085/wrinkling-and-folding-on-patched-elastic-surfaces-modulation-of-the-chemistry-and-pattern-size-of-microwrinkled-surfaces
#16
Aurora Nogales, Adolfo Del Campo, Tiberio Ezquerra, Juan Rodriguez-Hernandez
An unconventional strategy is proposed that takes advantage of localized high-deformation areas, referred to as folded wrinkles, to produce microstructured elastic surfaces with precisely controlled pattern dimensions and chemical distribution. For that purpose, elastic PDMS substrates were pre-stretched to a different extent and oxidized in particular areas using a mask. When the stretching was removed and the PDMS substrate exhibited out-of-plane deformations that largely depend on the applied pre-stretching...
May 18, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28518477/acute-oligodendrocyte-loss-with-persistent-white-matter-injury-in-a-third-trimester-equivalent-mouse-model-of-fetal-alcohol-spectrum-disorder
#17
Jessie Newville, Carlos Fernando Valenzuela, Lu Li, Lauren L Jantzie, Lee Anna Cunningham
Alcohol exposure during central nervous system (CNS) development can lead to fetal alcohol spectrum disorder (FASD). Human imaging studies have revealed significant white matter (WM) abnormalities linked to cognitive impairment in children with FASD; however, the underlying mechanisms remain unknown. Here, we evaluated both the acute and long-term impacts of alcohol exposure on oligodendrocyte number and WM integrity in a third trimester-equivalent mouse model of FASD, in which mouse pups were exposed to alcohol during the first 2 weeks of postnatal development...
May 18, 2017: Glia
https://www.readbyqxmd.com/read/28518185/osteogenic-potential-of-adipose-derived-macrospheroids-cocultured-with-cd11b-monocytes
#18
Hidemi Nakata, Maiko Yamamoto, Emi Okada, Tomoko Nagayama, Munemitsu Miyasaka, Shohei Kasugai, Shinji Kuroda
PURPOSE: Among potential cell-based therapies, adipose-derived stem cells (ASCs) have been proposed as a promising source of stem cells for tissue regeneration. Although many recent clinical trials have investigated the use of adipose tissue or ASCs in transplantation, analysis of the microstructures of outgrowing macrosized spheroids (macrospheroids) or three-dimensional coculture of ASC spheroids and monocyte/macrophage lineages has not been performed. The aim of this study was to analyze the microstructures of murine-derived ASC macrospheroids and the growth and osteogenic potential of these macrospheroids in a three-dimensional environment and after calcification induction by coculture with monocytes...
May 18, 2017: International Journal of Oral & Maxillofacial Implants
https://www.readbyqxmd.com/read/28517044/intercentrum-versus-pleurocentrum-growth-in-early-tetrapods-a-paleohistological-approach
#19
Marylène Danto, Florian Witzmann, Stephanie E Pierce, Nadia B Fröbisch
A variety of vertebral centrum morphologies have evolved within early tetrapods which range from multipartite centra consisting of intercentra and pleurocentra in stem-tetrapods, temnospondyls, seymouriamorphs, and anthracosaurs up to monospondylous centra in lepospondyls. With the present study, we aim to determine the formation of both intercentrum and pleurocentrum and asked whether these can be homologized based on their bone histology. Both intercentra and pleurocentra ossified endochondrally and periosteal bone was subsequently deposited on the outer surface of the centra...
May 18, 2017: Journal of Morphology
https://www.readbyqxmd.com/read/28516323/diffusion-tensor-imaging-findings-of-the-brainstem-in-subjects-with-tonsillar-ectopia
#20
Serpil Kurtcan, Alpay Alkan, Huseyin Yetis, Umit Tuzun, Ayse Aralasmak, Huseyin Toprak, Huseyin Ozdemir
We aimed to evaluate the differences between apparent diffusion coefficient (ADC), fractional anisotropy (FA), axial diffusivity (AD), and radial diffusivity (RD) values obtained from different cranial sites in subjects with Chiari I Malformation (CM-I) and borderline tonsillar ectopia (BTE), and to determine correlations between diffusion tensor imaging (DTI) metrics and the severity of tonsillar ectopia. A total of 73 subjects with CM-I and BTE and 35 control underwent MRI and DTI. In our study, ADC values measured from the level of medulla oblongata and the RD values measured in middle cerebellar peduncles, thalamus, and globus pallidus were higher in CM-I patients than in controls...
May 17, 2017: Acta Neurologica Belgica
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