Read by QxMD icon Read

Shear stress

Taehee Kang, Chulhun Park, Beom-Jin Lee
Cancer cells in the tumor microenvironment are affected by fluid shear stress generated by blood flow in the vascular microenvironment and interstitial flows in the tumor microenvironment. Thus, we investigated how fluidic shear stress affects cellular uptake as well as the endocytosis mechanism of nanoparticles using a biomimetic microfluidic system that mimics the human dynamic environment. Positively charged amino-modified polystyrene nanoparticles (PSNs) at 100 μg/mL were delivered to cancer cells under static and biomimetic dynamic conditions (0...
October 19, 2016: Archives of Pharmacal Research
James C Campbell, Alexander Tischer, Venkata Machha, Laurie Moon-Tasson, Banumathi Sankaran, Choel Kim, Matthew Auton
von Willebrand factor׳s (VWF) primary hemostatic responsibility is to deposit platelets at sites of vascular injury to prevent bleeding. This function is mediated by the interaction between the VWF A1 domain and the constitutively active platelet receptor, GPIbα. The crystal structure of the A1 domain harboring the von Willebrand disease (vWD) type 2M mutation p.Gly1324Ser has been recently published in the Journal of Biological Chemistry describing its effect on the function and structural stability of the A1 domain of VWF, "Mutational constraints on local unfolding inhibit the rheological adaptation of von Willebrand factor" [1]...
June 2016: Data in Brief
Xinlei Song, Shu Zhang, Yanna Cheng, Ting Zhao, Qianqian Lian, Lu Lu, Fengshan Wang
OBJECTIVES: To evaluate the resuscitative efficacy and the effect on reperfusion injury of two site-specific PEGylated human serum albumins modified with linear or branched PEG20kDa, compared with saline, 8% human serum albumin and 25% human serum albumin, in a hemorrhagic shock model. SETTING: Laboratory. SUBJECTS: Male Wistar rats. DESIGN: Prospective study. INTERVENTIONS: Rats were bled to hemorrhagic hypovolemic shock and resuscitated with different resuscitation fluids...
November 2016: Critical Care Medicine
Donato Belmonte, Carlo Gatti, Giulio Armando Ottonello, Pascal Richet, Marino Vetuschi Zuccolini
Thermodynamic and thermophysical properties of Na2SiO3 in the Cmc21 structural state are computed ab-initio using the hybrid B3LYP density functional method. The static properties at the athermal limit are first evaluated through a symmetry-preserving relaxation procedure. The thermodynamic properties that depend on vibrational frequencies viz, heat capacities, thermal expansion, thermal derivative of the bulk modulus, thermal correction to internal energy, enthalpy, Gibbs free energy, are then computed in the framework of quasi-harmonic approximation...
October 19, 2016: Journal of Physical Chemistry. A
Tiantian Zhang, Ti-Hsuan Ku, Yuanyuan Han, Ramkumar Subramanian, Iftikhar Ahmad Niaz, Hua Luo, Derrick Chang, Jian-Jang Huang, Yu-Hwa Lo
We present a method, Transient Induced Molecular Electronic Spectroscopy (TIMES), to detect protein-ligand interactions without any protein engineering or chemical modification. We developed a physics model for the TIMES signal and mathematically formulated the problem to attain physical insight of protein-ligand interactions without any disturbances by molecular probes, fluorescent labels, or immobilization of molecules. To demonstrate the functionality of this method, we have used the TIMES signals to find the dissociation constants for the affinity of reactions, the shear-stress dependent adsorption time of molecules on surface, and other interesting features of protein-ligand interaction in native conditions...
October 19, 2016: Scientific Reports
Tzu-Pin Shentu, Ming He, Xiaoli Sun, Jianlin Zhang, Fan Zhang, Brendan Gongol, Traci L Marin, Jiao Zhang, Liang Wen, Yinsheng Wang, Gregory G Geary, Yi Zhu, David A Johnson, John Y-J Shyy
OBJECTIVE: Cortactin translocates to the cell periphery in vascular endothelial cells (ECs) on cortical-actin assembly in response to pulsatile shear stress. Because cortactin has putative sites for AMP-activated protein kinase (AMPK) phosphorylation and sirtuin 1 (SIRT1) deacetylation, we examined the hypothesis that AMPK and SIRT1 coregulate cortactin dynamics in response to shear stress. APPROACH AND RESULTS: Analysis of the ability of AMPK to phosphorylate recombinant cortactin and oligopeptides whose sequences matched AMPK consensus sequences in cortactin pointed to Thr-401 as the site of AMPK phosphorylation...
October 6, 2016: Arteriosclerosis, Thrombosis, and Vascular Biology
Takao Sato, John Jose, Mohamed El-Mawardy, Dmitriy S Sulimov, Ralph Tölg, Gert Richardt, Mohamed Abdel-Wahab
Heterogeneity of neointimal thickness is observed after drug-eluting stents implantation in bifurcation lesions (BL). We evaluated the vascular response of everolimus-eluting bioresorbable scaffold (BRS) struts deployed at BL using optical coherence tomography (OCT). 50 patients (64 scaffolds) underwent follow-up OCT after BRS implantation. Cross-sectional areas of each BL with a side branch more than 1.5 mm were analyzed using OCT every 200 µm. All images were divided into three regions according to shear stress: the 1/2 circumference of the vessel opposite to the ostium (OO), the vessel wall adjacent to the ostium (AO) and the side-branch ostium (SO)...
October 18, 2016: International Journal of Cardiovascular Imaging
V V Muthusamy
Cardiovascular disease burden is increasing all over the world. The diagnosis of hypertension is considered when a person has persistently elevated BP (Systolic BP more than 140 mmHg and/or Diastolic BP more than 90 mmHg). Dyslipidemia denotes abnormal levels of lipids in the blood (Total Cholesterol >200 mg%, Low density lipoprotein (LDL) >100 mg%, Triglycerides (TGL) >150 mg% and High density lipoprotein (HDL) <40 mg in men and < 50 mg in women. Hypertension and Dyslipidemia constitute the important components of metabolic syndrome as per the definition of NCEP Guidelines-Adult Treatment Panel III (ATP III)...
September 2016: Journal of Hypertension
Peter F Davies, Elisabetta Manduchi, Christian J Stoeckert, Yi-Zhou Jiang
Hemodynamics creates a constantly changing physical and chemical environment to which the arterial endothelium is exquisitely sensitive. Biomechanical stresses are intrinsic to blood flow characteristics and blood pressure and therefore are important considerations in hypertension. Near branching anatomical sites in arteries, blood flow separates from the main flow to undergo complex multi-directional characteristics for a part of each cardiac cycle (collectively referred to as disturbed flow). Atherosclerosis and aneurysmal pathology develop preferentially at disturbed flow locations, particularly when an additional cardiovascular risk factor such as hypercholesterolemia or high blood pressure are present...
September 2016: Journal of Hypertension
Peter Kokkinos
A plethora of evidence exists supporting that structured aerobic exercise or activities that increase cardiorespiratory fitness (CRF) lower resting blood pressure (BP) in patients with hypertension (HTN). Relatively few studies have assessed the effects of anaerobic or resistance exercise on BP. Thus, its role in managing HTN is not defined. Also, possible risks related with exercise in hypertensive patients have not been adequately addressed.In addition to lowering BP, CRF attenuates the incidence of HTN. A substantial part of the age-related progression to HTN is not an inevitable outcome of aging as once thought, but a consequence of lifestyle characterized by high-fat/salt diets and physical inactivity...
September 2016: Journal of Hypertension
Soo-Kyeong Song, Sang-Rok Lee, Lae-Young Jung, Yi-Shik Kim, Sun-Hwa Lee, Kyoung-Suk Rhee, Jei-Keon Chae, Won-Ho Kim, Jae-Ki Ko
OBJECTIVE: Wall shear stress contributes to atherosclerosis progression and plaque rupture. There were limited studies for hypertension as influence factor on whole blood viscosity (WBV) in acute coronary syndrome (ACS) patients. We evaluated the relations between WBV and hypertension in patients who visited to the emergency room by acute chest pain. DESIGN AND METHOD: From April 2013 through June 2015, we prospectively enrolled 471 acute chest pain patients who visited emergency room...
September 2016: Journal of Hypertension
Jun Qiu, Fang-Fang Li
Mechanical properties of a single cell and its mechanical response under stimulation play an important role in regulating interactions between cell and extracellular matrix and affecting mechanotransduction. Osteocytes exhibit solid-like viscoelastic behavior in response to the interstitial fluid shear resulting from tissue matrix deformation. This study intends to quantitatively describe the mechanical behavior of osteocytes combining in vitro experiment and fluid-structure interaction (FSI) finite element (FE) model...
October 17, 2016: Biomechanics and Modeling in Mechanobiology
Jack R Staunton, Wilfred Vieira, King Leung Fung, Ross Lake, Alexus Devine, Kandice Tanner
One of the hallmarks of the malignant transformation of epithelial tissue is the modulation of stromal components of the microenvironment. In particular, aberrant extracellular matrix (ECM) remodeling and stiffening enhances tumor growth and survival and promotes metastasis. Type I collagen is one of the major ECM components. It serves as a scaffold protein in the stroma contributing to the tissue's mechanical properties, imparting tensile strength and rigidity to tissues such as those of the skin, tendons, and lungs...
September 2016: Cellular and Molecular Bioengineering
Akalabya Bissoyi, Arindam Bit, Bikesh Kumar Singh, Abhishek Kumar Singh, Pradeep Kumar Patra
Cell-matrix systems can be stored for longer period of time by means of cryopreservation. Cell-matrix and cell-cell interaction has been found to be critical in a number of basic biological processes. Tissue structure maintenance, cell secretary activity, cellular migration, and cell-cell communication all exist because of the presence of cell interactions. This complex and co-ordinated interaction between cellular constituents, extracellular matrix and adjacent cells has been identified as a significant contributor in the overall co-ordination of tissue...
October 17, 2016: Scientific Reports
Koushik Viswanathan, Narayan K Sundaram, Srinivasan Chandrasekar
Stick-slip in sliding of soft adhesive surfaces has long been associated with the propagation of Schallamach waves, a type of slow surface wave. Recently it was demonstrated using in situ experiments that two other kinds of slow waves-separation pulses and slip pulses-also mediate stick-slip (Viswanathan et al., Soft Matter, 2016, 12, 5265-5275). While separation pulses, like Schallamach waves, involve local interface detachment, slip pulses are moving stress fronts with no detachment. Here, we present a theoretical analysis of the propagation of these three waves in a linear elastodynamics framework...
October 17, 2016: Soft Matter
Carolyn R Schaeffer, Tra-My N Hoang, Craig M Sudbeck, Malik Alawi, Isaiah E Tolo, D Ashley Robinson, Alexander R Horswill, Holger Rohde, Paul D Fey
Staphylococcus epidermidis is a leading cause of hospital-associated infections, including those of intravascular catheters, cerebrospinal fluid shunts, and orthopedic implants. Multiple biofilm matrix molecules with heterogeneous characteristics have been identified, including proteinaceous, polysaccharide, and nucleic acid factors. Two of the best-studied components in S. epidermidis include accumulation-associated protein (Aap) and polysaccharide intercellular adhesin (PIA), produced by the enzymatic products of the icaADBC operon...
September 2016: MSphere
Jenny M Pedersen, Yoo-Sik Shim, Vaibhav Hans, Martin B Phillips, Jeffrey M Macdonald, Glenn Walker, Melvin E Andersen, Harvey J Clewell, Miyoung Yoon
Accurate prediction of metabolism is a significant outstanding challenge in toxicology. The best predictions are based on experimental data from in vitro systems using primary hepatocytes. The predictivity of the primary hepatocyte-based culture systems, however, is still limited due to well-known phenotypic instability and rapid decline of metabolic competence within a few hours. Dynamic flow bioreactors for three-dimensional cell cultures are thought to be better at recapitulating tissue microenvironments and show potential to improve in vivo extrapolations of chemical or drug toxicity based on in vitro test results...
2016: Frontiers in Bioengineering and Biotechnology
Xinxin Li, Bryan Ruddy, Andrew Taberner
Hypodermic injections have been the standard for transcutaneous drug delivery for many years. However, needle phobia, pain, and risks of needle-stick injuries have manifested in poor patient compliance. Needle-free jet injections (NFJI) have been developed to address these drawbacks but the reliability of dose and depth of delivery have been limited by a lack of control over jet parameters, and by variability in the skin's mechanical properties among individuals. Moreover, the device size and cost have been restrained by the high pressure (>20MPa) required to penetrate the skin...
October 13, 2016: Journal of Controlled Release: Official Journal of the Controlled Release Society
Xiao Liu, Libing Wang, Zhenze Wang, Zhengxing Li, Hongyan Kang, Yubo Fan, Anqiang Sun, Xiaoyan Deng
Helical flow has been introduced to improve the hemodynamic performance of vascular devices such as arterial grafts, stents and arteriovenous shunts to overcome the flow induced thrombus formation and intimal hyperplasia. However, the quite low intensity of helical flow in the existing devices may limit their function. To obtain desirably high intensity, inspired by the helical flow and tapered configuration of the arterial system, we proposed a new conceptual design of the medical devices, which take the form of a tapered helical shape...
September 23, 2016: Journal of Biomechanics
J Travis Hunsucker, Kelli Z Hunsucker, Harrison Gardner, Geoffrey Swain
The role of hydrodynamic wall shear stresses on the development of the fouling community structure and resulting frictional drag were examined using a commercially available fouling release coating. Immersed test panels were exposed to three different hydrodynamic treatments, one static and two dynamic (corresponding to an estimated wall shear stress of 7.0  and 25.5 Pa). The drag of the panels was measured in a hydrodynamic test chamber at discrete time intervals over 35 days. The fouling community composition on the static panels was significantly different from the organisms observed on the dynamic panels...
November 2016: Biofouling
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"