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Dynamic stretching

Salman Sohrabi, Yaling Liu
Pseudopotential lattice Boltzmann methods (LBMs) can simulate a phase transition in high-density ratio multiphase flow systems. If coupled with thermal LBMs through equation of state, they can be used to study instantaneous phase transition phenomena with a high-temperature gradient where only one set of formulations in an LBM system can handle liquid, vapor, phase transition, and heat transport. However, at lower temperatures an unrealistic spurious current at the interface introduces instability and limits its application in real flow system...
March 2018: Physical Review. E
Fenhong Song, Long Ma, Jing Fan, Qicheng Chen, Lihui Zhang, Ben Q Li
Molecular dynamic simulations were adopted to study the wetting properties of nanoscale droplets on rough silicon solid substrate subject to perpendicular electric fields. The effect of roughness factor and electric field strength on the static and dynamic wetting behaviors of a nano-droplet on a solid surface was investigated at the molecular level. Results show that the static contact angle tends to decrease slightly and show small difference with the increase of roughness factor, while it shows an obvious increase for the ramp-shaped surface because the appearing bottom space reduces the wettability of solid surface...
May 17, 2018: Nanomaterials
Joanna Kim, John A Cooper
Junctional integrity of endothelial monolayers is crucial to control movement of molecules and cells across the endothelium. Examining the structure and dynamics of cell junctions in endothelial monolayers, we discovered a role for septins. Contacts between adjacent endothelial cells were dynamic, with protrusions extending above or below neighboring cells. VE-cadherin was present at cell junctions, with a membrane-associated layer of F-actin. Septins localized at cell-junction membranes, in patterns distinct from VE-cadherin and F-actin...
May 17, 2018: Molecular Biology of the Cell
Samy Elian, Khaled Barakat
Closed sinus lifting is a unique technique in being simple and less invasive (Summers, Compendium 15(6):698, 1994). However, it is blind to assess the safety of sinus lining during lifting without perforation. Previously, sinus membrane was assessed endoscopically in an invasive way. We aimed to judge clinically the sinus membrane integrity after crestal elevation by a direct simple less invasive endoscopic visual assessment through the crestal osteotomy site. To confirm undetected perforation, the sinus membrane was monitored dynamically by introducing the endoscope through a trephined opening in the lateral wall of the sinus (Nkenke et al...
May 17, 2018: International Journal of Implant Dentistry
Ejaife O Agbani, Christopher M Williams, Yong Li, Marion Tj van den Bosch, Samantha F Moore, Adele Mauroux, Lorna Hodgson, Alan S Verkman, Ingeborg Hers, Alastair W Poole
In response to collagen stimulation, platelets use a coordinated system of fluid entry to undergo membrane ballooning, procoagulant spreading, and microvesiculation. We hypothesized that water entry was mediated by the water channel aquaporin-1 (AQP1) and aimed to determine its role in the platelet procoagulant response and thrombosis. We established that human and mouse platelets express AQP1 and localize to internal tubular membrane structures. However, deletion of AQP1 had minimal effects on collagen-induced platelet granule secretion, aggregation, or membrane ballooning...
May 17, 2018: JCI Insight
Ying Yuan, Jicun Li, Xin-Zheng Li, Feng Wang
The development of effective centroid potentials (ECPs) is explored with both the constrained-centroid and quasi-adiabatic force matching using liquid water as a test system. A trajectory integrated with the ECP is free of statistical noises that would be introduced when the centroid potential is approximated on the fly with a finite number of beads. With the reduced cost of ECP, challenging experimental properties can be studied in the spirit of centroid molecular dynamics. The experimental number density of H2 O is 0...
May 14, 2018: Journal of Chemical Physics
Qian Liu, Taku Hatta, Jun Qi, Haoyu Liu, Andrew R Thoreson, Peter C Amadio, Steven L Moran, Scott P Steinmann, Anne Gingery, Chunfeng Zhao
Surgical repair of rotator cuff tears presents a significant clinical challenge with high failure rates and inferior functional outcomes. Graft augmentation improves repair outcomes, however currently available grafting materials have limitations. While cell-seeded decellularized tendon slices may facilitate cell infiltration, promote tendon incorporation and preserve original mechanical strength, the unique fibrocartilage zone is yet to be successfully reestablished. In this study, we investigated the biological and mechanical properties of an engineered tendon-fibrocartilage-bone composite (TFBC) with cyclic tension (3% strain, 0...
May 15, 2018: Journal of Tissue Engineering and Regenerative Medicine
Andreas Singraber, Tobias Morawietz, Jörg Behler, Christoph Dellago
Using molecular dynamics simulations based on ab initio trained high-dimensional neural network potentials, we study the equation of state of liquid water at negative pressures. From density isobars computed for various pressures down to p = -230 MPa we determine the line of density maxima for two potentials based on the BLYP and the RPBE functionals, respectively. In both cases, dispersion corrections are included to account for non-local long-range correlations that give rise to van der Waals forces. We find that the density maximum persists down to the most negative pressures close to the spinodal instability...
May 15, 2018: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Samoa Asigau, Patricia G Parker
We sampled mosquitoes across 18 sites established at different elevations and stretching from the north to the south of Isla Santa Cruz, Galápagos. Two commonly occurring species, Ae. taeniorhynchus and Cx. quinquefasciatus, were collected along with environmental variables characteristic of the trapping sites to assess their influence on mosquito abundance and occurrence in the dry season of 2015. We captured Ae. taeniorhynchus at 14 out of 18 sites and Cx. quinquefasciatus at low and high elevation sites on Santa Cruz...
June 2018: Journal of Vector Ecology: Journal of the Society for Vector Ecology
Dustin Servello, Yuanzheng Gu, Chen Gu
Axonal varicosities are enlarged structures along the shafts of axons with a high degree of heterogeneity. They are present not only in brains with neurodegenerative diseases or injuries, but also in the normal brain. Here, we describe a newly-established micromechanical system to rapidly, reliably, and reversibly induce axonal varicosities, allowing us to understand the mechanisms governing varicosity formation and heterogeneous protein composition. This system represents a novel means to evaluate the effects of compression and shear stress on different subcellular compartments of neurons, different from other in vitro systems that mainly focus on the effect of stretching...
April 30, 2018: Journal of Visualized Experiments: JoVE
Thach Van Can, Johannes E McKay, Ralph T Weber, Chen Yang, Thierry Dubroca, Johan Van Tol, Stephen Hill, Robert G Griffin
We investigate a new time domain approach to dynamic nuclear polarization (DNP), the frequency-swept integrated solid effect (FS-ISE), utilizing a high power, broadband 94 GHz (3.35 T) pulse EPR spectrometer. The bandwidth of the spectrometer enabled measurement of the DNP Zeeman frequency/field profile that revealed two dominant polarization mechanisms, the expected ISE, and a new mechanism the stretched solid effect (S2E). At 94 GHz, despite the limitations in the microwave chirp pulse length (10 μs) and the repetition rate (2 kHz), we obtained signal enhancements up ~70 for the S2E and ~50 for the ISE...
May 14, 2018: Journal of Physical Chemistry Letters
Nicole C A van Engeland, Andreas M A O Pollet, Jaap M J den Toonder, Carlijn V C Bouten, Oscar M J A Stassen, Cecilia M Sahlgren
Cell signalling and mechanics influence vascular pathophysiology and there is an increasing demand for in vitro model systems that enable examination of signalling between vascular cells under hemodynamic conditions. Current 3D vessel wall constructs do not recapitulate the mechanical conditions of the native tissue nor do they allow examination of cell-cell interactions under relevant hemodynamic conditions. Here, we describe a 3D microfluidic chip model of arterial endothelial and smooth muscle cells where cellular organization, composition and interactions, as well as the mechanical environment of the arterial wall are mimicked...
May 14, 2018: Lab on a Chip
Qi Li, Niraj K Nirala, Yingchao Nie, Hsi-Ju Chen, Gary Ostroff, Junhao Mao, Qi Wang, Lan Xu, Y Tony Ip
The intestinal epithelium has a high cell turnover rate and is an excellent system to study stem cell-mediated adaptive growth. In the Drosophila midgut, the Ste20 kinase Misshapen, which is distally related to Hippo, has a niche function to restrict intestinal stem cell activity. We show here that, under low growth conditions, Misshapen is localized near the cytoplasmic membrane, is phosphorylated at the threonine 194 by the upstream kinase Tao, and is more active toward Warts, which in turn inhibits Yorkie...
May 9, 2018: Developmental Cell
Kwang-Im Oh, Carlos R Baiz
Up to 40% of intracellular water is confined due to the dense packing of macromolecules, ions, and osmolytes. Despite the large body of work concerning the effect of additives on biomolecular structure and stability, the role of crowding and heterogeneity is not well understood. Here, infrared spectroscopy and molecular dynamics simulations are used to describe the mechanisms by which crowding modulates hydrogen bonding interactions between water and dimethyl sulfoxide (DMSO). Specifically, we use formamide and dimethylformamide (DMF) as molecular crowders and show that S=O hydrogen bond populations in aqueous mixtures are increased by both amides...
May 9, 2018: Journal of Physical Chemistry. B
Sun-Young Ha, Jun-Ho Han, Yun-Hee Sung
The present study was conducted to investigate the effect of ankle strengthening exercise applied on unstable supporting surfaces on the proprioceptive sense and balance in adults with functional ankle instability. As for the study method, 30 adults with functional ankle instability were randomly assigned to an ankle strengthening exercise group and a stretching group on unstable supporting surfaces, and the interventions were implemented for 40 min. Before and after the interventions, a digital dual inclinometer was used to measure the proprioceptive sense of the ankle, the Balancia program was used to measure static balance ability, and the functional reach test was used to measure dynamic balance ability...
April 2018: Journal of Exercise Rehabilitation
A Kortyna, D M B Lesko, D J Nesbitt
The combination of a pulsed supersonic slit-discharge source and single-mode difference frequency direct absorption infrared spectroscopy permit first high resolution infrared study of the iodomethyl (CH2 I) radical, with the CH2 I radical species generated in a slit jet Ne/He discharge and cooled to 16 K in the supersonic expansion. Dual laser beam detection and collisional collimation in the slit expansion yield sub-Doppler linewidths (60 MHz), an absolute frequency calibration of 13 MHz, and absorbance sensitivities within a factor of two of the shot-noise limit...
May 7, 2018: Journal of Chemical Physics
Miklós Kellermayer, Dominik Sziklai, Zsombor Papp, Brennan Decker, Eszter Lakatos, Zsolt Mártonfalvi
Titin is a giant protein spanning between the Z- and M-lines of the sarcomere. In the A-band titin is associated with the myosin thick filament. It has been speculated that titin may serve as a blueprint for thick-filament formation due to the super-repeat structure of its A-band domains. Accordingly, titin might provide a template that determines the length and structural periodicity of the thick filament. Here we tested the titin ruler hypothesis by mixing titin and myosin at in situ stoichiometric ratios (300 myosins per 12 titins) in buffers of different ionic strength (KCl concentration range 100-300 mM)...
May 5, 2018: Journal of Structural Biology
Alexander C S Douglass, Joel B Harley
Guided wave structural health monitoring is widely researched for remotely inspecting large structural areas. To detect, locate, and characterize damage, guided wave methods often compare data to a baseline signal. Yet, environmental variations create large differences between the baseline and the collected measurements. These variations hide damage signatures and cause false detection. Temperature compensation algorithms, such as baseline signal stretch and the scale transform have been used to optimally realign data to a baseline...
May 2018: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
Hyesu Jang, Yudong Qiu, Marshall E Hutchings, Minh Nguyen, Louise A Berben, Lee-Ping Wang
The CO2 reduction electrocatalyst [Fe4 N(CO)12 ]- (abbrev. 1 - ) reduces CO2 to HCO2 - in a two-electron, one-proton catalytic cycle. Here, we employ ab initio calculations to estimate the first two redox potentials of 1 - and explore the pathway of a side reaction involving CO dissociation from 1 3- . Using the BP86 density functional approximation, the redox potentials were computed with a root mean squared error of 0.15 V with respect to experimental data. High temperature Born-Oppenheimer molecular dynamics was employed to discover a reaction pathway of CO dissociation from 1 3- with a reaction energy of +10...
March 14, 2018: Chemical Science
Dongxiao Hao, Zhiwei Yang, Teng Gao, Zhiqi Tian, Lei Zhang, Shengli Zhang
Current cholesteryl ester transfer protein (CETP) inhibitors are designed based on the unglycosylated crystal structure, and most of them have failed to cure cardiovascular disease (CVD). It is particularly important for us to investigate the glycosylation structure of CETP (CETP-G) and effect of glycans on the structure and function of CETP. Here, we used a total of 3.0-μs molecular dynamics trajectories of nascent structure of CETP (CETP-N) and CETP-G to study their structural differentiations, to shed new light on the CETP-mediated lipid exchange...
May 3, 2018: Proteins
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