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https://www.readbyqxmd.com/read/28098315/a-ph-responsive-wormlike-micellar-system-of-a-noncovalent-interaction-based-surfactant-with-a-tunable-molecular-structure
#1
Wanli Kang, Pengxiang Wang, Haiming Fan, Hongbin Yang, Caili Dai, Xia Yin, Yilu Zhao, Shujun Guo
Responsive wormlike micelles are very useful in a number of applications, whereas it is still challenging to create dramatic viscosity changes in wormlike micellar systems. Here we developed a pH-responsive wormlike micellar system based on a noncovalent constructed surfactant, which is formed by the complexation of N-erucamidopropyl-N,N-dimethylamine (UC22AMPM) and citric acid at the molar ratio of 3 : 1 (EACA). The phase behavior, aggregate microstructure and viscoelasticity of EACA solutions were investigated by macroscopic appearance observation, rheological and cryo-TEM measurements...
January 18, 2017: Soft Matter
https://www.readbyqxmd.com/read/28098306/effective-viscosity-and-dynamics-of-spreading-epithelia-a-solvable-model
#2
C Blanch-Mercader, R Vincent, E Bazellières, X Serra-Picamal, X Trepat, J Casademunt
Collective cell migration in spreading epithelia in controlled environments has become a landmark in our current understanding of fundamental biophysical processes in development, regeneration, wound healing or cancer. Epithelial monolayers are treated as thin layers of a viscous fluid that exert active traction forces on the substrate. The model is exactly solvable and shows a broad range of applicabilities for the quantitative analysis and interpretation of force microscopy data of monolayers from a variety of experiments and cell lines...
January 18, 2017: Soft Matter
https://www.readbyqxmd.com/read/28098305/phase-behaviour-and-temperature-responsive-properties-of-a-gemini-surfactant-brij-30-water-system
#3
Chuanhong Han, Yan Guo, Xiaoxiao Chen, Meihuan Yao, Yingtian Zhang, Qirui Zhang, Xilian Wei
The phase behaviour of a ternary system composed of cationic gemini surfactant 2-hydroxypropyl-1,3-bis(myristyldimethylammonium chloride) (14-3(OH)-14(2Cl)), nonionic surfactant polyoxyethylene laurel ether (C12H25(OCH2CH2)10OH, Brij-30) and H2O was studied and its phase diagram was determined. In several different phase regions identified in the phase diagram, the viscoelastic worm-like micellar solution region was investigated. The focus of the investigation was the increase in the viscosity of the micellar solution with the temperature and the Brij-30 content, as suggested by a partial region of the triangular phase diagram...
January 18, 2017: Soft Matter
https://www.readbyqxmd.com/read/28097669/mathematical-modeling-of-rotary-blood-pumps-in-a-pulsatile-in-vitro-flow-environment
#4
Tohid Pirbodaghi
Nowadays, sacrificing animals to develop medical devices and receive regulatory approval has become more common, which increases ethical concerns. Although in vivo tests are necessary for development and evaluation of new devices, nonetheless, with appropriate in vitro setups and mathematical models, a part of the validation process can be performed using these models to reduce the number of sacrificed animals. The main aim of this study is to present a mathematical model simulating the hydrodynamic function of a rotary blood pump (RBP) in a pulsatile in vitro flow environment...
January 18, 2017: Artificial Organs
https://www.readbyqxmd.com/read/28097480/average-flow-generation-by-a-pulsating-flow-near-a-curved-interface
#5
Lyudmila S Klimenko, Dmitry V Lyubimov
This paper is devoted to the study of curvature influence on the average flow generation near the fluid interface. The time averaging of a non-uniform pulsating flow often results in a nonzero average flow in the bulk. The well-known average flow occurs near a solid surface, the so-called Schlichting mechanism of the average flow generation. For flows with a free surface there is the other known mechanism of Longuet-Higgins, according to which the average flow is generated by surface waves traveling on a free surface...
January 2017: European Physical Journal. E, Soft Matter
https://www.readbyqxmd.com/read/28097478/study-of-the-influence-of-formulation-variables-in-bioadhesive-emulgels-using-response-surface-methodology
#6
Ana Ochoa-Andrade, M Emma Parente, Álvaro Jimenez-Kairuz, Lucía Boinbaser, Annibal Torregrosa
The aim of the present work was to study the main formulation variables that influence attributes of bioadhesive emulgels based on a combination of polymers, using response surface methodology (RSM). Bioadhesive products continue to gain attention in topical cutaneous administration as they allow long residence times on the application site, which is important when a long dermal action and a reduced product administration frequency are desired. A Box-Behnken design of experiments (DoE) was introduced to study the effect of formulation variables on quality attributes of the emulgels...
January 17, 2017: AAPS PharmSciTech
https://www.readbyqxmd.com/read/28093330/effect-of-solution-plasma-process-with-bubbling-gas-on-physicochemical-properties-of-chitosan
#7
Fengming Ma, Pu Li, Baiqing Zhang, Qun Fu, Zhenyu Wang, Cailian Gu
In the present work, solution plasma process (SPP) with bubbling gas was used to prepare oligochitosan. The effect of SPP irradiation with bubbling gas on the degradation of chitosan was evaluated by the intrinsic viscosity reduction rate and the degradation kinetic. The formation of OH radical was studied. Changes of the physicochemical properties of chitosan were measured by scanning electron microscopy, X-ray diffraction, and thermogravimetric analysis, as well as ultraviolet-visible, Fourier-transform infrared, and (13)C nuclear magnetic resonance spectroscopy...
January 13, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28092912/production-and-rheological-properties-of-welan-gum-produced-by-sphingomonas-sp-atcc-31555-with-different-nitrogen-sources
#8
Xiaopeng Xu, Zuoming Nie, Zhiyong Zheng, Li Zhu, Xiaobei Zhan
This study aimed to investigate the effect of nitrogen sources on the production and rheological properties of welan gum produced by Sphingomonas sp. ATCC 31555. Six different nitrogen sources were used for ATCC 31555 fermentation, and 2 of these were further analyzed due to their more positive influence on welan gum production and bacterial biomass. Bacterial biomass, welan gum yield, welan viscosity, molecular weight, monosaccharide composition, acyl content, and welan structure were analyzed. Welan gum production and the biomass concentration of ATCC 31555 were higher in media containing NaNO3 and beef extract...
January 17, 2017: Journal of Molecular Microbiology and Biotechnology
https://www.readbyqxmd.com/read/28092504/wall-shear-rate-measurement-validation-of-a-new-method-through-multiphysics-simulations
#9
Stefano Ricci, Abigail Swillens, Alessandro Ramalli, Patrick Segers, Piero Tortoli
Wall shear stress is known to affect the vessel endothelial function and to be related to important pathologies like the development of atherosclerosis. It is defined as the product of the blood viscosity by the blood velocity gradient at the wall position, i.e., the wall shear rate (WSR). The WSR measurement is particularly challenging in important cardiovascular sites, like the carotid bifurcation, because of the related complex flow configurations characterized by high spatial and temporal gradients, wall movement, and clutter noise...
January 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28092431/test-paper-like-photonic-crystal-viscometer
#10
Yuqi Zhang, Qianqian Fu, Jianping Ge
A test-paper-like photonic crystal (PC) viscometer is fabricated based on the positive correlation between viscosity and the infiltration time for viscous liquid to entirely soak the PC film. It can be broadly used in different occasions to quickly determine the viscosity for many liquids, considering its portable and disposable characteristics and the requirement of little samples.
January 16, 2017: Small
https://www.readbyqxmd.com/read/28091909/modes-of-hypotensive-action-of-dihydroquercetin-in-arterial-hypertension
#11
M B Plotnikov, O I Aliev, A V Sidekhmenova, A Yu Shamanaev, A M Anishchenko, A V Nosarev, E A Pushkina
We studied the effect of dihydroquercetin (20 mg/kg/day intragastrically for 6 weeks) on mean BP and macro- and microrheological blood parameters in hypertensive SHR rats; in vitro effect of dihydroquercetin on the tone in thoracic aorta rings isolated from hypertensive SHR rats were also examined. At the end of the treatment course, the mean BP in the experimental rats decreased by 11%; the left ventricular mass index by 2%, and whole blood viscosity by 7-10% in comparison with control SHR rats; erythrocyte aggregation half-time increased by 15%; plasma viscosity, hematocrit, and erythrocyte deformability did not change...
January 14, 2017: Bulletin of Experimental Biology and Medicine
https://www.readbyqxmd.com/read/28091626/dynamic-contact-angles-in-oil-aqueous-polymer-solutions
#12
Amer Al-Shareef, P Neogi, Baojun Bai
Polymer flooding is an important process in enhanced oil recovery. The displacement front is unstable when low viscosity brine displaces the heavy crude oil in the reservoir. Water-soluble polymers are added to the brine to increase its viscosity which stabilizes the displacement process. To analyze the displacement process at the micro-level, we have investigated the dynamic contact angles in silicone oil-polymer (polyethylene oxide) solution and for the first time. The dynamic contact angle is the apparent contact angle at the three-phase contact line which governs the capillary pressure, and thus is important for the displacement process...
January 16, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28091442/fluoride-release-recharging-ability-and-bond-strength-of-glass-ionomer-cements-to-sound-and-caries-affected-dentin
#13
E Kucukyilmaz, S Savas, F Kavrik, B Yasa, M S Botsali
OBJECTIVES: The aim of this in vitro study was to evaluate the microtensile bond strength (μTBS) of different glass ionomer cements (GICs) on sound/caries-affected dentin and to assess the fluoride release/recharging ability. METHODS: After creating artificial caries lesions, teeth with sound and caries-affected dentin were assigned to be restored with one of the GICs: Ketac N100; GC Equia; GCP Glass Fill, and tested using a microtensile test. Ten of each material were prepared, and fluoride ion-release was measured at 10 different intervals...
February 2017: Nigerian Journal of Clinical Practice
https://www.readbyqxmd.com/read/28088672/using-discrete-multi-physics-for-detailed-exploration-of-hydrodynamics-in-an-in-vitro-colon-system
#14
A Alexiadis, K Stamatopoulos, W Wen, H K Batchelor, S Bakalis, M Barigou, M J H Simmons
We developed a mathematical model that describes the motion of viscous fluids in the partially-filled colon caused by the periodic contractions of flexible walls (peristalsis). In-vitro data are used to validate the model. The model is then used to identify two fundamental mechanisms of mass transport: the surfing mode and the pouring mode. The first mechanism is faster, but only involves the surface of the liquid. The second mechanism causes deeper mixing, and appears to be the main transport mechanism. Based on the gained understanding, we propose a series of measures that can improve the reliability of in-vitro models...
January 9, 2017: Computers in Biology and Medicine
https://www.readbyqxmd.com/read/28088478/comparison-of-the-adjuvant-activity-of-emulsions-with-different-physicochemical-properties-on-the-antibody-response-towards-the-venom-of-west-african-carpet-viper-echis-ocellatus
#15
Juan Manuel Valverde, Karina Rodríguez, María Herrera, Álvaro Segura, Mariángela Vargas, Mauren Villalta, Mavis Montero, Jose María Gutiérrez, Guillermo León
Adjuvant emulsions are widely used to enhance the antibody response of the animals used as immunoglobulin source for producing antivenoms. Usually, the adjuvant activity of emulsions is attributed both to their ability to trigger "danger" signals from cells in which they induce death, and to form depots from which immunogens are slowly released. However, there is contradictory evidence suggesting that adjuvant activity of emulsions is independent of the dispersion type and the rate of immunogen release. In order to test how physical properties of emulsions, composed of mineral oil and water, affect their ability to enhance the antibody response towards snake venoms, we compared water-in-oil (W/O) emulsions prepared at volume ratios of 70/30, 50/50 or 30/70, a 50/50 oil-in-water (O/W) emulsion, and a water-in-oil-in-water (W/O/W) multiple emulsion...
January 11, 2017: Toxicon: Official Journal of the International Society on Toxinology
https://www.readbyqxmd.com/read/28088012/new-4-4-chlorophenyl-2-2-6-2%C3%A2-terpyridine-ruthenium-ii-complexes-synthesis-characterization-interaction-with-dna-bsa-and-cytotoxicity-studies
#16
Milan M Milutinović, Ana Rilak, Ioannis Bratsos, Olivera Klisurić, Milan Vraneš, Nevenka Gligorijević, Siniša Radulović, Živadin D Bugarčić
In this study, we have developed a series of new monofunctional Ru(II) complexes of the general formula mer-[Ru(Cl-Ph-tpy)(N-N)Cl]Cl in which Cl-Ph-tpy is 4'-(4-chlorophenyl)-2,2':6',2″-terpyridine, N-N is a bidentate chelating ligand (1,2-diaminoethane (en, 1), 1,2-diaminocyclohexane (dach, 2) or 2,2'-bipyridine (bpy, 3)). All complexes were fully characterized by elemental analysis and spectroscopic techniques (IR, UV-Vis, 1D and 2D NMR). Their chemical behavior in aqueous solution was studied by UV-Vis and NMR spectroscopy showing that all compounds are relatively labile leading to the formation of the corresponding aqua species 1aq-3aq...
October 14, 2016: Journal of Inorganic Biochemistry
https://www.readbyqxmd.com/read/28079842/increased-erythrocyte-aggregation-and-oxidative-stress-in-patients-with-idiopathic-interstitial-pneumonia
#17
Erhan Ugurlu, Emine Kilic-Toprak, Goksel Altinisik, Ozgen Kilic-Erkek, Betul Cengiz, Vural Kucukatay, Hande Senol, Ismail Hakki Akbudak, Yusuf Ekbic, Melek Bor-Kucukatay
BACKGROUND: Hemorheological properties are important determinants of tissue oxygenation. Although hemorheological alterations in various lung diseases have been well-defined, no information is available about the effects of idiopathic interstitial pneumonia (IIP) on hemorheological parameters. OBJECTIVES: The aim of this study was to investigate hemorheological parameters (erythrocyte deformability, aggregation, and plasma viscosity -PV) and associated oxidative stress indices in patients with IIP...
December 23, 2016: Sarcoidosis, Vasculitis, and Diffuse Lung Diseases: Official Journal of WASOG
https://www.readbyqxmd.com/read/28079299/a-platinum-blue-complex-exerts-its-cytotoxic-activity-via-dna-damage-and-induces-apoptosis-in-cancer-cells
#18
Zelal Adiguzel, Seniz Ozalp-Yaman, Gokalp Celik, Safia Salem, Tugba Bagci-Onder, Filiz Senbabaoglu, Yüksel Cetin, Ceyda Acilan
Here, we describe the characteristics of a Pt-blue complex [Pt4 (2-atp)8 (H2 O)(OH)] (2-atp: 2-aminothiophenol) as a prodrug for its DNA-binding properties and its use in cancer therapy. The nature of the interaction between the Pt-blue complex and DNA was evaluated based on spectroscopic measurements, the electronic absorption spectra, thermal behavior, viscosity, fluorometric titration and agarose gel electrophoresis. Our results suggested that the compound was able to partially intercalate DNA and appeared to induce both single and double stranded breaks (DBS) on DNA in vitro, but no DSBs in cells...
January 12, 2017: Chemical Biology & Drug Design
https://www.readbyqxmd.com/read/28079121/local-geology-controlled-the-feasibility-of-vitrifying-iron-age-buildings
#19
Fabian B Wadsworth, Michael J Heap, David E Damby, Kai-Uwe Hess, Jens Najorka, Jérémie Vasseur, Dominik Fahrner, Donald B Dingwell
During European prehistory, hilltop enclosures made from polydisperse particle-and-block stone walling were exposed to temperatures sufficient to partially melt the constituent stonework, leading to the preservation of glassy walls called 'vitrified forts'. During vitrification, the granular wall rocks partially melt, sinter viscously and densify, reducing inter-particle porosity. This process is strongly dependent on the solidus temperature, the particle sizes, the temperature-dependence of the viscosity of the evolving liquid phase, as well as the distribution and longevity of heat...
January 12, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28078609/enhanced-thermophysical-properties-via-pao-superstructure
#20
Zahra Pournorouz, Amirhossein Mostafavi, Aditya Pinto, Apparao Bokka, Junha Jeon, Donghyun Shin
For the last few years, molten salt nanomaterials have attracted many scientists for their enhanced specific heat by doping a minute concentration of nanoparticles (up to 1% by weight). Likewise, enhancing the specific heat of liquid media is important in many aspects of engineering such as engine oil, coolant, and lubricant. However, such enhancement in specific heat was only observed for molten salts, yet other engineering fluids such as water, ethylene glycol, and oil have shown a decrease of specific heat with doped nanoparticles...
December 2017: Nanoscale Research Letters
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