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https://www.readbyqxmd.com/read/28212299/exogenous-and-endogenous-hydrogen-sulfide-protects-gastric-mucosa-against-the-formation-and-time-dependent-development-of-ischemia-reperfusion-induced-acute-lesions-progressing-into-deeper-ulcerations
#1
Marcin Magierowski, Katarzyna Magierowska, Magdalena Hubalewska-Mazgaj, Zbigniew Sliwowski, Robert Pajdo, Grzegorz Ginter, Slawomir Kwiecien, Tomasz Brzozowski
Hydrogen sulfide (H₂S) is an endogenous mediator, synthesized from l-cysteine by cystathionine γ-lyase (CSE), cystathionine β-synthase (CBS) or 3-mercaptopyruvate sulfurtransferase (3-MST). The mechanism(s) involved in H₂S-gastroprotection against ischemia/reperfusion (I/R) lesions and their time-dependent progression into deeper gastric ulcerations have been little studied. We determined the effect of l-cysteine, H₂S-releasing NaHS or slow H₂S releasing compound GYY4137 on gastric blood flow (GBF) and gastric lesions induced by 30 min of I followed by 3, 6, 24 and 48 h of R...
February 15, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28212219/drug-infusion-systems-technologies-performance-and-pitfalls
#2
Uoo R Kim, Robert A Peterfreund, Mark A Lovich
This review aims to broadly describe drug infusion technologies and raise subtle but important issues arising from infusion therapy that can potentially lead to patient instability and morbidity. Advantages and disadvantages of gravity-dependent drug infusion are described and compared with electromechanical approaches for precise control of medication infusion, including large-volume peristaltic and syringe pumps. This review discusses how drugs and inert carriers interact within infusion systems and outlines several complexities and potential sources of drug error...
February 16, 2017: Anesthesia and Analgesia
https://www.readbyqxmd.com/read/28208477/bifurcation-induced-by-the-aspect-ratio-in-a-turbulent-von-k%C3%A3-rm%C3%A3-n-swirling-flow
#3
Olivier Liot, Javier Burguete
We evaluate the effect of the aspect ratio, i.e., the distance between the propellers H divided by the diameter D, on the slow dynamics of a von Kármán swirling flow driven by two propellers in a closed cylinder. We use a cell with a fixed diameter D but where the distance between the propellers can be turned continuously and where the inertia from the propellers can also be changed using different gears. No change on the dynamics is observed when the momentum of inertia is modified. Some dramatic changes of the shear layer position are observed modifying the aspect ratio Γ=H/D...
January 2017: Physical Review. E
https://www.readbyqxmd.com/read/28208369/traffic-congestion-and-the-lifetime-of-networks-with-moving-nodes
#4
Xianxia Yang, Jie Li, Cunlai Pu, Meichen Yan, Rajput Ramiz Sharafat, Jian Yang, Konstantinos Gakis, Panos M Pardalos
For many power-limited networks, such as wireless sensor networks and mobile ad hoc networks, maximizing the network lifetime is the first concern in the related designing and maintaining activities. We study the network lifetime from the perspective of network science. In our model, nodes are initially assigned a fixed amount of energy moving in a square area and consume the energy when delivering packets. We obtain four different traffic regimes: no, slow, fast, and absolute congestion regimes, which are basically dependent on the packet generation rate...
January 2017: Physical Review. E
https://www.readbyqxmd.com/read/28203477/imaging-and-quantitative-analysis-of-the-interstitial-space-in-the-caudate-nucleus-in-a-rotenone-induced-rat-model-of-parkinson-s-disease-using-tracer-based-mri
#5
Deyong Lv, Jingbo Li, Hongfu Li, Yu Fu, Wei Wang
Parkinson's disease (PD) is characterized by pathological changes within several deep structures of the brain, including the substantia nigra and caudate nucleus. However, changes in interstitial fluid (ISF) flow and the microstructure of the interstitial space (ISS) in the caudate nucleus in PD have not been reported. In this study, we used tracer-based magnetic resonance imaging (MRI) to quantitatively investigate the alterations in ISS and visualize ISF flow in the caudate nucleus in a rotenone-induced rat model of PD treated with and without madopar...
February 2017: Aging and Disease
https://www.readbyqxmd.com/read/28195195/peptoids-successfully-inhibit-the-growth-of-gram-negative-e-coli-causing-substantial-membrane-damage
#6
Biljana Mojsoska, Gustavo Carretero, Sylvester Larsen, Ramona Valentina Mateiu, Håvard Jenssen
Peptoids are an alternative approach to antimicrobial peptides that offer higher stability towards enzymatic degradation. It is essential when developing new types of peptoids, that mimic the function of antimicrobial peptides, to understand their mechanism of action. Few studies on the specific mechanism of action of antimicrobial peptoids have been described in the literature, despite the plethora of studies on the mode of action of antimicrobial peptides. Here, we investigate the mechanism of action of two short cationic peptoids, rich in lysine and tryptophan side chain functionalities...
February 14, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28194824/left-intraventricular-pressure-gradients-improvement-after-aortic-valve-replacement-in-aortic-stenosis-patients
#7
Miguel Guerra, Pedro Mendes-Ferreira, Rui Adão, Eulália Pereira, Manuela Vieira, André P Lourenço, Carmen Brás-Silva, Pedro Bastos, Luís Vouga, Adelino F Leite-Moreira
The present study was conducted to characterize left intraventicular pressure gradients, a marker of normal cardiac function, in patients with severe aortic stenosis, a condition which interferes with ventricular filling and emptying. In 10 patients (4 male; mean age 71.3 ± 4.8 years old) undergoing aortic valve replacement, 2 high-fidelity pressure catheters were inserted inside the left ventricle cavity through an apical puncture and positioned in the apex and outflow-tract below the aortic valve. Pressures were continuously acquired and gradients were calculated as apical minus outflow-tract pressure, before and immediately after aortic valve replacement...
February 14, 2017: Experimental Physiology
https://www.readbyqxmd.com/read/28182575/response-of-a-physiological-controller-for-ventricular-assist-devices-during-acute-patho-physiological-events-an-in-vitro-study
#8
Anastasios Petrou, Panagiotis Pergantis, Gregor Ochsner, Raffael Amacher, Thomas Krabatsch, Volkmar Falk, Mirko Meboldt, Marianne Schmid Daners
The current paper analyzes the performance of a physiological controller for turbodynamic ventricular assist devices (tVADs) during acute patho-physiological events. The numerical model of the human blood circulation implemented on our hybrid mock circulation was extended in order to simulate the Valsalva maneuver (VM) and premature ventricular contractions (PVCs). The performance of an end-diastolic volume (EDV)-based physiological controller for VADs, named preload responsive speed (PRS) controller was evaluated under VM and PVCs...
February 9, 2017: Biomedizinische Technik. Biomedical Engineering
https://www.readbyqxmd.com/read/28180005/the-role-of-urotensin-ii-and-atherosclerotic-risk-factors-in-patients-with-slow-coronary-flow
#9
REVIEW
Ömer Şatıroğlu, Murtaza Emre Durakoğlugil, Mustafa Çetin, Yüksel Çiçek, Turan Erdoğan, Hakan Duman
BACKGROUND: Slow coronary flow (SCF) is an angiographic finding characterized with delayed opacification of epicardial coronary arteries without obstructive coronary disease. Urotensin II (UII) is an important vascular peptide, which has an important role in hypertension, coronary artery disease, and vascular remodeling in addition to potent vasoconstrictor effect. OBJECTIVES: We investigated UII levels, hypertension, and other atherosclerotic risk factors in patients with SCF, a variety of coronary artery disease...
December 2016: Interventional Medicine & Applied Science
https://www.readbyqxmd.com/read/28177017/surface-shear-viscosity-as-a-macroscopic-probe-of-amyloid-fibril-formation-at-a-fluid-interface
#10
Vignesh S Balaraj, Philip C H Zeng, Sean P Sanford, Samantha A McBride, Aditya Raghunandan, Juan M Lopez, Amir H Hirsa
Amyloidogenesis of proteins is of wide interest because amyloid structures are associated with many diseases, including Alzheimer's and type II diabetes. Dozens of different proteins of various sizes are known to form amyloid fibrils. While there are numerous studies on the fibrillization of insulin induced by various perturbations, shearing at fluid interfaces has not received as much attention. Here, we present a study of human insulin fibrillization at room temperature using a deep-channel surface viscometer...
February 8, 2017: Soft Matter
https://www.readbyqxmd.com/read/28174322/4d-microvascular-analysis-reveals-that-regenerative-angiogenesis-in-ischemic-muscle-produces-a-flawed-microcirculation
#11
John-Michael Arpino, Zengxuan Nong, Fuyan Li, Hao Yin, Nour W Ghonaim, Stephanie Milkovich, Brittany Balint, Caroline O'Neil, Graham M Fraser, Daniel Goldman, Christopher G Ellis, J G Pickering
RATIONALE: Angiogenesis occurs following ischemic injury to skeletal muscle and enhancing this response has been a therapeutic goal. However, to appropriately deliver oxygen, a precisely organized and exquisitely responsive microcirculation must form. Whether these network attributes exist in a regenerated microcirculation is unknown and methodologies for answering this have been lacking. OBJECTIVE: To develop 4D methodologies for elucidating microarchitecture and function of the reconstructed microcirculation in skeletal muscle...
February 7, 2017: Circulation Research
https://www.readbyqxmd.com/read/28170101/torsion-estimation-of-particle-paths-through-porous-media-observed-by-in-situ-time-resolved-microtomography
#12
C Blankenburg, A Rack, C Daul, J Ohser
The torsion distribution of cell paths in two-phase flow of a cell suspension through a porous medium is an important quantity for chromatographic processes. It can be estimated from cell tracking in sequences of three-dimensional images of a suspension pumped through the medium, where the images are acquired by in-situ time-resolved microtomography using synchrotron radiation and inline phase contrast modus. This contribution presents a new method for estimating path torsion from discrete positions, where the estimation is based on an appropriate discretization of the differential-geometric formula of the torsion of a space curve...
February 7, 2017: Journal of Microscopy
https://www.readbyqxmd.com/read/28169477/localised-intravascular-coagulation-complicating-venous-malformations-in-children-associations-and-therapeutic-options
#13
REVIEW
Kevin Y Zhuo, Susan Russell, Orli Wargon, Susan Adams
Venous malformations are slow-flow congenital vascular malformations that enlarge as the child ages and may be associated with localised intravascular coagulation, a consumptive coagulopathy characterised by elevated D-dimer and decreased fibrinogen levels. The authors review the known correlations between localised intravascular coagulation and venous malformation number, size and planes involved, and call attention to the concept of the progression of localised intravascular coagulopathy as the child ages and their venous malformations enlarge...
February 7, 2017: Journal of Paediatrics and Child Health
https://www.readbyqxmd.com/read/28167399/adapted-mr-velocimetry-of-slow-liquid-flow-in-porous-media
#14
Li Huang, Gerd Mikolajczyk, Ekkehard Küstermann, Michaela Wilhelm, Stefan Odenbach, Wolfgang Dreher
MR velocimetry of liquid flow in opaque porous filters may play an important role in better understanding the mechanisms of deep bed filtration. With this knowledge, the efficiency of separating the suspended solid particles from the vertically flowing liquid can be improved, and thus a wide range of industrial applications such as wastewater treatment and desalination can be optimized. However, MR velocimetry is challenging for such studies due to the low velocities, the severe B0 inhomogeneity in porous structures, and the demand for high spatial resolution and an appropriate total measurement time during which the particle deposition will change velocities only marginally...
January 27, 2017: Journal of Magnetic Resonance
https://www.readbyqxmd.com/read/28166201/downregulation-of-pck2-remodels-tricarboxylic-acid-cycle-in-tumor-repopulating-cells-of-melanoma
#15
S Luo, Y Li, R Ma, J Liu, P Xu, H Zhang, K Tang, J Ma, N Liu, Y Zhang, Y Sun, T Ji, X Liang, X Yin, Y Liu, W Tong, Y Niu, N Wang, X Wang, B Huang
For cancer cells to proliferate, a balance must be built between biomass-forming, glucose-metabolized intermediates and ATP production. How intrinsic glucose carbon flow regulates this balance remains unclear. Here we show that mitochondrial phosphoenolpyruvate carboxykinase (PCK2), the hub molecule linking tricarboxylic acid (TCA) cycle, glycolysis and gluconeogenesis by conversion of mitochondrial oxaloacetate (OAA) to phosphoenolpyruvate, regulates glucose carbon flow direction in stem-like cells that repopulate tumors (tumor-repopulating cells (TRCs))...
February 6, 2017: Oncogene
https://www.readbyqxmd.com/read/28164461/flexible-polygon-mirror-based-laser-scanning-microscope-platform-for-multiphoton-in-vivo-imaging
#16
Y X Li, V Gautam, A Brüstle, I A Cockburn, V R Daria, C Gillespie, K Gaus, C Alt, W M Lee
Commercial microscopy systems make use of tandem scanning i.e. either slow or fast scanning. We constructed, for the first time, an advanced control system capable of delivering a dynamic line scanning speed ranging from 2.7 kHz to 27 kHz and achieve variable frame rates from 5 Hz to 50 Hz (512 × 512). The dynamic scanning ability is digitally controlled by a new customized open-source software named PScan1.0. This permits manipulation of scanning rates either to gain higher fluorescence signal at slow frame rate without increasing laser power or increase frame rates to capture high speed events...
February 6, 2017: Journal of Biophotonics
https://www.readbyqxmd.com/read/28163357/tube-side-mass-transfer-for-hollow-fibre-membrane-contactors-operated-in-the-low-graetz-range
#17
C Y Wang, E Mercer, F Kamranvand, L Williams, A Kolios, A Parker, S Tyrrel, E Cartmell, E J McAdam
Transformation of the tube-side mass transfer coefficient derived in hollow fibre membrane contactors (HFMC) of different characteristic length scales (equivalent diameter and fibre length) has been studied when operated in the low Graetz range (Gz<10). Within the low Gz range, mass transfer is generally described by the Graetz problem (Sh=3.67) which assumes that the concentration profile comprises a constant shape over the fibre radius. In this study, it is experimentally evidenced that this assumption over predicts mass transfer within the low Graetz range...
February 1, 2017: Journal of Membrane Science
https://www.readbyqxmd.com/read/28157998/numerical-simulations-of-fast-axis-instability-of-vector-solitons-in-mode-locked-fiber-lasers
#18
Yueqing Du, Xuewen Shu, Peiyun Cheng
We demonstrate the fast-axis instability in mode-locked fiber lasers numerically for the first time. We find that the energy of the fast mode will be transferred to the slow mode when the strong pump strength makes the soliton period short. A nearly linearly polarized vector soliton along the slow-axis could be generated under certain cavity parameters. The final polarization of the vector soliton is related to the initial polarization of the seed pulse. Two regimes of energy exchanging between the slow mode and the fast mode are explored and the direction of the energy flow between two modes depends on the phase difference...
January 23, 2017: Optics Express
https://www.readbyqxmd.com/read/28157430/factors-determining-in-vitro-lung-deposition-of-albuterol-aerosol-delivered-by-ventolin-metered-dose-inhaler
#19
Rajoshi Biswas, Nicola A Hanania, Ashutosh Sabharwal
BACKGROUND: The effectiveness of metered-dose inhalers (MDIs) in delivering medication to the lungs highly depends on its correct usage technique. Current guidelines state optimal technique for high lung deposition should include a slow inhalation (>5 seconds) at an inspiratory flow rate of 30 L/min and inhaler actuation at the start of inhalation. However, these recommendations were based on clinical studies using CFC (chlorofluorocarbon)-MDIs and in vitro studies of HFA (hydrofluoroalkane)-MDIs using idealized MDI techniques of uniform inhalation and actuation, disregarding the nonuniform techniques of actual patients...
February 3, 2017: Journal of Aerosol Medicine and Pulmonary Drug Delivery
https://www.readbyqxmd.com/read/28156037/ultra-fast-supercritical-hydrothermal-synthesis-of-tobermorite-under-thermodynamically-metastable-conditions
#20
Marta Diez-Garcia, Juan J Gaitero, Jorge S Dolado, Cyril Aymonier
Tobermorite is a fibrillar mineral of the family of calcium silicates. In spite of not being abundant in nature, its structure and properties are reasonably well known because of its interest in the construction industry. Currently, tobermorite is synthesized by hydrothermal methods at mild temperatures. The problem is that such processes are very slow (>5 h) and temperature cannot be increased to speed them up because tobermorite is metastable over 130 °C. Furthermore the product obtained is generally foil-like and not very crystalline...
February 3, 2017: Angewandte Chemie
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