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Jessica M Motherwell, Mohammad S Azimi, Kristine Spicer, Natascha G Alves, Nicholas A Hodges, Jerome W Breslin, Prasad V G Katakam, Walter L Murfee
An emerging challenge in tissue engineering biomimetic models is recapitulating the physiological complexity associated with real tissues. Recently, our laboratory introduced the rat mesentery culture model as an ex vivo experimental platform for investigating the multi-cellular dynamics involved in angiogenesis within an intact microvascular network using time-lapse imaging. A critical question remains whether the vessels maintain their functionality. The objective of this study was to determine whether vascular smooth muscle cells in cultured microvascular networks maintain the ability to constrict...
May 19, 2017: Scientific Reports
Daniel F Monte, Miriam R Fernandes, Louise Cerdeira, Tiago A de Souza, Andressa Mem, Bernadette D G M Franco, Mariza Landgraf, Nilton Lincopan
We present here the draft genome sequences of two colistin-resistant mcr-1-carrying Escherichia coli strains belonging to sequence type 74 (ST74) and ST1850, isolated from commercial chicken meat in Brazil. Assembly of this draft genome resulted in 5,022,083 and 4,950,681 bp, respectively, revealing the presence of the IncX4 plasmid-mediated mcr-1 gene responsible for resistance to colistin.
May 18, 2017: Genome Announcements
Xiao-Jun Wu, Nathalie Dinguirard, Grzegorz Sabat, Hong-di Lui, Laura Gonzalez, Michael Gehring, Utibe Bickham-Wright, Timothy P Yoshino
Interactions between early developing Schistosoma mansoni larval stages and the hemolymph of its snail intermediate host represent the first molecular encounter with the snail's immune system. To gain a more comprehensive understanding of this early parasite-host interaction, biotinylated sporocyst tegumental membrane (Mem) proteins and larval transformation proteins (LTP) were affixed to streptavidin-agarose beads and used as affinity matrices to enrich for larval-reactive plasma proteins from susceptible (NMRI) and resistant (BS-90) strains of the snail Biomphalaria glabrata...
May 2017: PLoS Pathogens
A W B Silva, R P Ribeiro, V G Menezes, R S Barberino, J R S Passos, A M P Dau, J J N Costa, L R F Melo, F T G Bezerra, M A M Donato, C A Peixoto, M H T Matos, P B D Gonçalves, R van den Hurk, J R V Silva
This study was conducted to detect the protein expression of TNF-α system members (TNF-α/TNFR1/TNFR2) in bovine ovarian follicles and to evaluate the effects of TNF-α or dexamethasone on the survival and growth of primordial follicles in vitro, as well as on gene expression in cultured ovarian tissue. It was hypothesized that TNF-α induces follicular atresia in ovarian tissues cultured in vitro, and that dexamethasone suppresses the production of endogenous TNF-α, which can improve follicle viability in vitro...
May 6, 2017: Animal Reproduction Science
Majed S Al-Ghamdi, Ayman M Alneamy, Sangtak Park, Beichen Li, Mahmoud E Khater, Eihab M Abdel-Rahman, Glenn R Heppler, Mustafa Yavuz
We experimentally investigate the primary superharmonic of order two and subharmonic of order one-half resonances of an electrostatic MEMS actuator under direct excitation. We identify the parameters of a one degree of freedom (1-DOF) generalized Duffing oscillator model representing it. The experiments were conducted in soft vacuum to reduce squeeze-film damping, and the actuator response was measured optically using a laser vibrometer. The predictions of the identified model were found to be in close agreement with the experimental results...
May 13, 2017: Sensors
Paweena Wongwitwichot, Jasadee Kaewsrichan
PURPOSE: Mesenchymal stem cells (MSCs) are multipotent adult stem cells and present in practically all tissues but originally identified within the bone marrow (BM). The differentiation potential of these cells is generally impaired when culturing in vitro for cell expansion. The aim of this study is to speedily increase the numbers of bone marrow derived mesenchymal stem cells (BM-MSCs) with substantially maintaining their differentiation potential in vitro and improving bone formation in vivo...
May 11, 2017: Advances in Medical Sciences
Udit Narula, Andres Ruiz, McKinley McQuaide, Thomas B DeMarse, Bruce C Wheeler, Gregory J Brewer
Communication between different sub regions of the hippocampus is fundamental to learning and memory. However accurate knowledge about information transfer between sub regions from access to the activity in individual axons is lacking. MEMS devices with microtunnels connecting two sub networks have begun to approach this problem but the commonly used 10 μm wide tunnels frequently measure signals from multiple axons. To reduce this complexity, we compared polydimethylsiloxane (PDMS) microtunnel devices each with a separate tunnel width of 2...
2017: PloS One
Claudio Abels, Vincenzo Mariano Mastronardi, Francesco Guido, Tommaso Dattoma, Antonio Qualtieri, William M Megill, Massimo De Vittorio, Francesco Rizzi
The response to different force load ranges and actuation at low energies is of considerable interest for applications of compliant and flexible devices undergoing large deformations. We present a review of technological platforms based on nitride materials (aluminum nitride and silicon nitride) for the microfabrication of a class of flexible micro-electro-mechanical systems. The approach exploits the material stress differences among the constituent layers of nitride-based (AlN/Mo, Si x N y /Si and AlN/polyimide) mechanical elements in order to create microstructures, such as upwardly-bent cantilever beams and bowed circular membranes...
May 10, 2017: Sensors
Maria D Manrique-Juarez, Fabrice Mathieu, Victoria Shalabaeva, Jean Cacheux, Sylvain Rat, Liviu Nicu, Thierry Leïchlé, Lionel Salmon, Gábor Molnár, Azzedine Bousseksou
We report on a bistable MEMS device actuated by spin-crossover molecules. The device consists of a freestanding silicon microcantilever with an integrated piezoresistive detection system, which was coated with a 140 nm thick film of the [Fe(HB(tz)3 )2 ] (tz=1,2,4-triazol-1-yl) molecular spin-crossover complex. Switching from the low-spin to the high-spin state of the ferrous ions at 338 K led to a reversible upward bending of the cantilever in agreement with the change in the lattice parameters of the complex...
May 10, 2017: Angewandte Chemie
Xiao Han, Rui Xue, Hong-Jie Yuan, Tian-Yang Wang, Juan Lin, Jie Zhang, Bo Liang, Jing-He Tan
It is known that oocytes and cumulus cells (CCs) are more resistant to apoptosis than other compartments of the antral follicle. However, although oocyte-secreted factors (OSFs) have been found to be involved in suppressing bovine CC apoptosis, little is known about the intra-cellular mechanisms by which OSFs render CCs resistant to apoptosis. Here we show that coculture with mouse or pig cumulus-denuded oocytes, culture with recombinant mouse growth differentiation factor-9 (GDF-9) or culture in pig oocyte-conditioned medium (POCM) significantly inhibited CC apoptosis of mouse oocytectomized cumulus oophorus complexes (OOXs)...
May 8, 2017: Biology of Reproduction
Shaozhen Song, Jingjiang Xu, Shaojie Men, Tueng T Shen, Ruikang K Wang
A novel phase stabilization technique is demonstrated with significant improvement in the phase stability of a micro-electromechanical (MEMS) vertical cavity surface-emitting laser (VCSEL) based swept-source optical coherence tomography (SS-OCT) system. Without any requirements of hardware modifications, the new fully numerical phase stabilization technique features high tolerance to acquisition jitter, and significantly reduced budget in computational effort. We demonstrate that when measured with biological tissue, this technique enables a phase sensitivity of 89 mrad in highly scattering tissue, with image ranging distance of up to 12...
May 9, 2017: Journal of Biophotonics
Chengxu Dong, Meixiang Gao, Chuanwei Guo, Lin Lin, Donghui Wu, Limin Zhang
Metacommunity theory provides an understanding of how ecological processes regulate local community assemblies. However, few field studies have evaluated the underlying mechanisms of a metacommunity on a small scale through revealing the relative roles of spatial and environmental filtering in structuring local community composition. Based on a spatially explicit sampling design in 2012 and 2013, this study aims to evaluate the underlying processes of a soil mite metacommunity on a small spatial scale (50 m) in a temperate deciduous forest located at the Maoershan Ecosystem Research Station, Northeast China...
2017: PloS One
Fariba Akrami, Elaheh Ferdosi Shahandashti, Yousef Yahyapour, Mohsen Sadeghi, Soraya Khafri, Abazar Pournajaf, Ramazan Rajabnia
Multi-drug resistant isolates of Acinetobacter baumannii have created therapeutic problems worldwide. This current study was intended to determine the Integron types, gene cassettes and antimicrobial resistance profile of A. baumannii isolated from BAL samples in Babol, north of Iran. During a 15-month period, 35 A. baumannii isolates were studied. Different classes of antimicrobial agents were used to determine the resistance ratios. Multiplex-PCR was used to detect different types of integrons and associated gene cassettes...
May 4, 2017: Microbial Pathogenesis
Ingmar Visser, Rens Poessé
The linear ballistic accumulator (LBA) model (Brown & Heathcote, , Cogn. Psychol., 57, 153) is increasingly popular in modelling response times from experimental data. An R package, glba, has been developed to fit the LBA model using maximum likelihood estimation which is validated by means of a parameter recovery study. At sufficient sample sizes parameter recovery is good, whereas at smaller sample sizes there can be large bias in parameters. In a second simulation study, two methods for computing parameter standard errors are compared...
May 2017: British Journal of Mathematical and Statistical Psychology
Longqing Cong, Prakash Pitchappa, Chengkuo Lee, Ranjan Singh
Controlling the phase of local radiation by using exotic metasurfaces has enabled promising applications in a diversified set of electromagnetic wave manipulation such as anomalous wavefront deflection, flat lenses, and holograms. Here, we theoretically and experimentally demonstrate an active phase transition in a micro-electromechanical system-based metadevice where both the phase response and the dispersion of the metamaterial cavity are dynamically tailored. The phase transition is determined by the radiative and the absorptive losses in a metal-insulator-metal cavity that obeys the coupled-mode theory...
May 4, 2017: Advanced Materials
Vladimir S Lyubopytov, Alexey P Porfirev, Stanislav O Gurbatov, Sujoy Paul, Martin F Schumann, Julijan Cesar, Mohammadreza Malekizandi, Mohammad T Haidar, Martin Wegener, Arkadi Chipouline, Franko Küppers
In this paper, we experimentally demonstrate simultaneous wavelength and orbital angular momentum (OAM) multiplexing/demultiplexing of 10 Gbit/s data streams using a new on-chip micro-component-tunable MEMS-based Fabry-Perot filter integrated with a spiral phase plate. In the experiment, two wavelengths, each of them carrying two channels with zero and nonzero OAMs, form four independent information channels. In case of spacing between wavelength channels of 0.8 nm and intensity modulation, power penalties relative to the transmission of one channel do not exceed 1...
May 1, 2017: Optics Express
Alister T Boags, Pin Chia Hsu, Mohd Firdaus Samsudin, Peter J Bond, Syma Khalid
Bacteria are protected by complex molecular architectures known as the cell envelope. The cell envelope is composed of regions with distinct chemical compositions and physical properties; namely mem-branes and a cell wall. To develop novel antibiotics to combat pathogenic bacteria, molecular level knowledge of the structure, dynamics and interplay between the chemical components of the cell envelope that surrounds bacterial cells is imperative. In addition, conserved mo-lecular patterns associated with the bacterial envelope are recognized by receptors as part of the mammalian defensive response to infection, and an improved under-standing of bacteria-host interactions would facilitate the search for novel immunotherapeutics...
May 3, 2017: Journal of Physical Chemistry Letters
Jeremy T Robinson, Maxim K Zalalutdinov, Cory D Cress, James C Culbertson, Adam L Friedman, Andrew Merrill, Brian J Landi
Using graphene nanomechanical resonators we demonstrate the extent to which the mechanical properties of multilayer graphene films are controllable, in real time, through introduction and re-arrangement of defects. We show both static and re-entrant (cyclical) changes in the tensile stress using a combination of ion implantation, chemical functionalization and thermal treatment. While the dramatic increase in static tensile stress achievable through laser annealing can be of importance for various MEMS applications, we view the direct observation of a time-variable stress as even more significant...
May 2, 2017: ACS Nano
Mattia Sist, Ellen Marie Jensen Hedegaard, Sebastian Christensen, Niels Bindzus, Karl Frederik Færch Fischer, Hidetaka Kasai, Kunihisa Sugimoto, Bo Brummerstedt Iversen
SnTe is a promising thermoelectric and topological insulator material. Here, the presumably simple rock salt crystal structure of SnTe is studied comprehensively by means of high-resolution synchrotron single-crystal and powder X-ray diffraction from 20 to 800 K. Two samples with different carrier concentrations (sample A = high, sample B = low) have remarkably different atomic displacement parameters, especially at low temperatures. Both samples contain significant numbers of cation vacancies (1-2%) and ordering of Sn vacancies possibly occurs on warming, as corroborated by the appearance of multiple phases and strain above 400 K...
September 1, 2016: IUCrJ
C A L Williams, R B Panerai, T G Robinson, V J Haunton
BACKGROUND: We tested the hypothesis that paradigms from the Addenbrooke's Cognitive Examination (ACE-III), including those that had not been studied using TCD previously (novel) versus those which had been (established), would elicit changes in CBF velocity (CBFv). NEW METHOD: Healthy subjects were studied with bilateral transcranial Doppler (TCD), beat-to-beat blood pressure (Finapres), continuous electrocardiogram (ECG), and end-tidal CO2 (nasal capnography)...
April 26, 2017: Journal of Neuroscience Methods
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