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https://www.readbyqxmd.com/read/27933585/effect-of-rheology-and-poloxamers-properties-on-release-of-drugs-from-silicon-dioxide-gel-filled-hard-gelatin-capsules-a-further-enhancement-of-viability-of-liquid-semisolid-matrix-technology
#1
Misbah Sultana, Mobashar Ahmad Butt, Tariq Saeed, Rizwan Mahmood, Saeed Ul Hassan, Khalid Hussain, Syed Atif Raza, Muhammad Ahsan, Nadeem Irfan Bukhari
The liquid and semisolid matrix technology, filling liquids, semi-solids and gels in hard gelatin capsule are promising, thus, there is a need of enhanced research interest in the technology. Therefore, the present study was aimed to investigate isoniazid (freely soluble) and metronidazole (slightly soluble) gels filled in hard gelatin capsules for the effect of poloxamers of different viscosities on release of the drugs. Gel of each drug (10% w/w, particle size 180-250 μm), prepared by mixing poloxamer and 8% w/w hydrophilic silicon dioxide (Aerosil® A200), was assessed for rheology, dispersion stability and release profile...
December 8, 2016: AAPS PharmSciTech
https://www.readbyqxmd.com/read/27931721/mesoporous-silica-fillers-and-resin-composition-effect-on-dental-composites-cytocompatibility
#2
Nina Attik, Franck Hallay, Laurence Bois, Arnaud Brioude, Brigitte Grosgogeat, Pierre Colon
OBJECTIVE: Many new dental composites containing mesoporous silica fillers have been developed to improve rheological properties and enhance the resin-filler interface. To investigate the correlation between the cytocompatibility of several dental composites and their composition; two aspects have been considered: presence of bisphenol A (BPA)-glycidyl methacrylate (Bis-GMA) or triethyleneglycol-dimethacrylate (TEGDMA) among the resin monomers and presence of porous particles among the filler blends...
December 5, 2016: Dental Materials: Official Publication of the Academy of Dental Materials
https://www.readbyqxmd.com/read/27929164/the-role-of-the-binding-salt-sodium-salicylate-in-semidilute-ionic-cetylpyridinium-chloride-micellar-solutions-a-rheological-and-scattering-study
#3
D Gaudino, R Pasquino, J Stellbrink, N Szekely, M Krutyeva, A Radulescu, W Pyckhout-Hintzen, N Grizzuti
The micellar system based on cetylpyridinium chloride (CPyCl) and sodium salicylate (NaSal) in brine solution is investigated on both macro- and micro-length scales through rheology and scattering measurements. The linear viscoelasticity of the system and its structural parameters are explored by systematically changing the amount of NaSal over an extremely wide range of concentrations, thus producing salt-to-surfactant molar ratios from zero to about 8.5. As a result, the well-known non-monotonic behaviour of the zero-shear rate viscosity as a function of salinity can be connected to micellar morphological changes, whose driving force is represented by the simultaneous binding and screening actions of NaSal...
December 8, 2016: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/27926839/circular-dichroism-spectroscopy-of-collagen-fibrillogenesis-a-new-use-for-an-old-technique
#4
Kathryn E Drzewiecki, Daniel R Grisham, Avanish S Parmar, Vikas Nanda, David I Shreiber
Type-I collagen assembles in a stepwise, hierarchic fashion from the folding of the triple helix to the assembly of fibrils into fibers. The mature assembled fibers are crucial for tissue structure and mechanics, cell interactions, and other functions in vivo. Although triple helix folding can be followed with the use of optical methods such as circular dichroism (CD) spectroscopy, fibrillogenesis is typically measured by alternative methods such as turbidity, rheology, and microscopy. Together, these approaches allow for investigation of the mechanical properties and architectures of collagen-based scaffolds and excised tissues...
December 6, 2016: Biophysical Journal
https://www.readbyqxmd.com/read/27924928/unified-rheology-of-vibro-fluidized-dry-granular-media-from-slow-dense-flows-to-fast-gas-like-regimes
#5
Andrea Gnoli, Antonio Lasanta, Alessandro Sarracino, Andrea Puglisi
Granular media take on great importance in industry and geophysics, posing a severe challenge to materials science. Their response properties elude known soft rheological models, even when the yield-stress discontinuity is blurred by vibro-fluidization. Here we propose a broad rheological scenario where average stress sums up a frictional contribution, generalizing conventional μ(I)-rheology, and a kinetic collisional term dominating at fast fluidization. Our conjecture fairly describes a wide series of experiments in a vibrofluidized vane setup, whose phenomenology includes velocity weakening, shear thinning, a discontinuous thinning transition, and gaseous shear thickening...
December 7, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27924469/a-methylcellulose-and-collagen-based-temperature-responsive-hydrogel-promotes-encapsulated-stem-cell-viability-and-proliferation-in-vitro
#6
Christina Payne, Eimear B Dolan, Janice O'Sullivan, Sally-Ann Cryan, Helena M Kelly
With the number of stem cell-based therapies emerging on the increase, the need for novel and efficient delivery technologies to enable therapies to remain in damaged tissue and exert their therapeutic benefit for extended periods, has become a key requirement for their translation. Hydrogels, and in particular, thermoresponsive hydrogels, have the potential to act as such delivery systems. Thermoresponsive hydrogels, which are polymer solutions that transform into a gel upon a temperature increase, have a number of applications in the biomedical field due to their tendency to maintain a liquid state at room temperature, thereby enabling minimally invasive administration and a subsequent ability to form a robust gel upon heating to physiological temperature...
December 6, 2016: Drug Delivery and Translational Research
https://www.readbyqxmd.com/read/27923141/development-and-characterization-of-electrosprayed-alyssum-homolocarpum-seed-gum-nanoparticles-for-encapsulation-of-d-limonene
#7
Khadije Khoshakhlagh, Arash Koocheki, Mohebbat Mohebbi, Alireza Allafchian
In this study, the feasibility of developing Alyssum homolocarpum seed gum (AHSG) nanocapsules containing d-limonene by electrospraying has been investigated. d-limonene emulsions with constant AHSG (0.5% w/w) and various flavor concentrations (10-30% based on gum weight) with 0.1% Tween 20 were electrosprayed at 20kV and 0.1ml/h of flow rate. The effects of key parameters of emulsions (rheological properties, droplet size, surface tension and electrical conductivity) on the morphology of structures have been studied...
November 21, 2016: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/27920496/fabrication-of-anti-vitiligo-ointment-containing-psoralea-corylifolia-in-vitro-and-in-vivo-characterization
#8
Irshad Hussain, Nisar Hussain, Abdul Manan, Abdur Rashid, Barkat Khan, Sattar Bakhsh
BACKGROUND: Vitiligo is a repugnant and odious dermatological malady of the time. It has an detrimental impact on the pigmentation of the human skin as a result of the destruction of cutaneous melanocytes. It affects 1%-2% of the population worldwide. Different therapeutic regimens have been deployed to treat vitiligo, but none of them could stand alone to be stated as a perfect cure. Recently, a change has been observed through novel experimental-designed optimization leading to the development of an anti-vitiligo ointment containing Psoralea corylifolia (PC) seed powder...
2016: Drug Design, Development and Therapy
https://www.readbyqxmd.com/read/27919690/comparative-analysis-of-different-xanthan-samples-by-atomic-force-microscopy
#9
Julia Teckentrup, Orooba Al-Hammood, Tim Steffens, Hanna Bednarz, Volker Walhorn, Karsten Niehaus, Dario Anselmetti
The polysaccharide xanthan which is produced by the γ-proteobacterium Xanthomonas campestris is used as a food thickening agent and rheologic modifier in numerous food, cosmetics and technical applications. Its great commercial importance stimulated biotechnological approaches to optimize the xanthan production. By targeted genetic modification the metabolism of Xanthomonas can be modified in such a way that the xanthan production efficiency and/or the shear-thickening potency is optimized. Using atomic force microscopy (AFM) the secondary structure of single xanthan polymers produced by the wild type Xanthomonas campestris B100 and several genetically modified variations were analyzed...
December 2, 2016: Journal of Biotechnology
https://www.readbyqxmd.com/read/27919336/tissue-reactions-to-ionizing-radiation-oral-mucosa
#10
Sylvia Gruber, Wolfgang Dörr
Radiotherapy is one of the most effective treatment strategies for solid malignancies, including head-and-neck tumors (HNT). Oral mucositis is the most frequent, often dose-limiting early adverse event of radio(chemo)therapy for HNT. The oral mucosal response is - like that of typical turnover tissues - based on radiation-induced impairment of epithelial proliferation and cell production, in face of ongoing physiological cell differentiation and cell loss, consequently resulting in hypoplasia and eventually mucosal ulceration...
October 2016: Mutation Research
https://www.readbyqxmd.com/read/27918043/thermoresponsive-structured-emulsions-based-on-the-fibrillar-self-assembly-of-natural-saponin-glycyrrhizic-acid
#11
Zhili Wan, Yingen Sun, Lulu Ma, Jian Guo, Jinmei Wang, Shouwei Yin, Xiaoquan Yang
We report the novel use of the naturally occurring saponin, glycyrrhizic acid (GA) as a structuring material to transform liquid oil into a soft-solid structured emulsion system. The GA nanofibrils from the anisotropic self-assembly of GA molecules were first used as stabilizers to fabricate olive oil-in-water emulsions using a facile one-step emulsification at high temperature. Then, the obtained emulsions were further self-organized into the emulsion gel by applying a subsequent cooling to trigger the gel network formation, which is mostly due to the enhanced noncovalent interactions among GA fibrils in the continuous phase as well as at the droplet surface...
December 5, 2016: Food & Function
https://www.readbyqxmd.com/read/27917932/latent-curing-systems-stabilized-by-reaction-equilibrium-in-homogeneous-mixtures-of-benzoxazine-and-amine
#12
Jun Wang, Ya Zhen Xu, Ya Fei Fu, Xiang Dong Liu
Latent curing systems are widely used in industrial thermosets in applications such as adhesion, coating, and composites. Despite many attempts to improve the practicality of this dormant reaction system, the majority of commercially available latent products still use particulate hardeners or liquid compounds with blocked active groups. These formulations generally lack fluidity or rapid reaction characteristics and thus are problematic in some industry applications. Here we describe a novel concept that stabilizes highly reactive benzoxazine/amine mixtures by reaction equilibrium...
December 5, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27915492/preparation-and-in-vitro-evaluation-of-melatonin-loaded-ha-pva-gelformulations
#13
Sakine Tuncay Tanrıverdi, Catalina Natalia Cheaburu-Yilmaz, Sonia Carbone, Özgen Özer
Melatonin loaded hyaluronic acid and poly(vinyl alcohol) gels were prepared by using freeze-thaw technique and an emulsion method followed by freeze-thaw technique to produce a new synergistic system for topical application. Freeze-thaw hydrogels and emulgels were characterized by means of Fourier Transform Infrared Spectroscopy, rheology and swelling tests. The porous structure of the hydrogels was shown by scanning electron microscopy observations and thermal properties were tested by Differential Scanning Calorimetry measurements...
December 5, 2016: Pharmaceutical Development and Technology
https://www.readbyqxmd.com/read/27914388/ultrasonic-method-to-characterize-shear-wave-propagation-in-micellar-fluids
#14
Carolina Amador, Bruno L Otilio, Randall R Kinnick, Matthew W Urban
Viscoelastic micellar fluid characteristics have been measured with mechanically generated shear waves and showed good agreement to shear oscillatory methods. In this paper, shear waves in wormlike micellar fluids using ultrasound were successfully generated and detected. Micellar fluids of different concentrations (100, 200, 300, and 400 mM) were studied with ultrasound-based and conventional rheology methods. The measured micellar fluid complex modulus from oscillatory shear tests between 0.001 and 15.91 Hz was characterized with an extended Maxwell fluid model...
September 2016: Journal of the Acoustical Society of America
https://www.readbyqxmd.com/read/27913343/a-frequency-shift-method-to-measure-shear-wave-attenuation-in-soft-tissues
#15
Simon Bernard, Siavash Kazemirad, Guy Cloutier
In vivo quantification of shear wave attenuation in soft tissues may help to better understand human tissue rheology and lead to new diagnostic strategies. Attenuation is difficult to measure in acoustic radiation force elastography because the shear wave amplitude decreases due to a combination of diffraction and viscous attenuation. Diffraction correction requires assuming a cylindrical wavefront and an isotropic propagation medium, which may not be the case in some applications. In this study, the frequency shift method, used in ultrasound imaging and seismology, was adapted for shear wave attenuation measurement in elastography...
December 1, 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/27913147/electro-kinetically-driven-peristaltic-transport-of-viscoelastic-physiological-fluids-through-a-finite-length-capillary-mathematical-modelling
#16
Dharmendra Tripathi, Ashu Yadav, O Anwar Bég
Analytical solutions are developed for the electro-kinetic flow of a viscoelastic biological liquid in a finite length cylindrical capillary geometry under peristaltic waves. The Jefferys' non-Newtonian constitutive model is employed to characterize rheological properties of the fluid. The unsteady conservation equations for mass and momentum with electro-kinetic and Darcian porous medium drag force terms are reduced to a system of steady linearized conservation equations in an axisymmetric coordinate system...
November 29, 2016: Mathematical Biosciences
https://www.readbyqxmd.com/read/27910991/structural-fingerprints-of-yielding-mechanisms-in-attractive-colloidal-gels
#17
Arman Boromand, Safa Jamali, João M Maia
Core-Modified Dissipative Particle Dynamics (CM-DPD) with a modified depletion potential and full hydrodynamics description is used to study non-equilibrium properties of colloidal gels with short range attraction potentials at an intermediate volume fraction (ϕ = 0.2) under start-up shear deformation. Full structural and rheological analysis using the stress fabric tensor complemented by bond number and bond distribution evolution under flow reveals that similarly to dilute colloidal gels, flow-induced anisotropy and strain-induced stretching of bonds are present during the first yielding transition...
December 2, 2016: Soft Matter
https://www.readbyqxmd.com/read/27910869/multiparameter-mechanical-and-morphometric-screening-of-cells
#18
Mahdokht Masaeli, Dewal Gupta, Sean O'Byrne, Henry T K Tse, Daniel R Gossett, Peter Tseng, Andrew S Utada, Hea-Jin Jung, Stephen Young, Amander T Clark, Dino Di Carlo
We introduce a label-free method to rapidly phenotype and classify cells purely based on physical properties. We extract 15 biophysical parameters from cells as they deform in a microfluidic stretching flow field via high-speed microscopy and apply machine-learning approaches to discriminate different cell types and states. When employing the full 15 dimensional dataset, the technique robustly classifies individual cells based on their pluripotency, with accuracy above 95%. Rheological and morphological properties of cells while deforming were critical for this classification...
December 2, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27910438/a-micro-nano-rheometer-for-the-mechanics-of-soft-matter-at-interfaces
#19
Léo Garcia, Chloé Barraud, Cyril Picard, Jérôme Giraud, Elisabeth Charlaix, Benjamin Cross
We present a nano-rheometer based on the dynamic drainage flow between a sphere and a plane from bulk regime to highly confined regime. The instrument gives absolute measurements of the viscosity of simple liquids in both regimes. For complex fluids, the measurements involve the viscosity and the elastic modulus. The device operates on distances ranging over four orders of magnitude from 1 nm to 10 μm, bridging rheological properties from the macroscopic to the molecular scale. This allows to measure an hydrodynamic or visco-elastic boundary condition and to explore the causes of the boundary condition at the microscopic level...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27907987/microrheology-of-growing-escherichia-coli-biofilms-investigated-by-using-magnetic-force-modulation-atomic-force-microscopy
#20
Tiansheng Gan, Xiangjun Gong, Holger Schönherr, Guangzhao Zhang
Microrheology of growing biofilms provides insightful information about its structural evolution and properties. In this study, the authors have investigated the microrheology of Escherichia coli (strain HCB1) biofilms at different indentation depth (δ) by using magnetic force modulation atomic force microscopy as a function of disturbing frequency (f). As δ increases, the dynamic stiffness (ks) for the biofilms in the early stage significantly increases. However, it levels off when the biofilms are matured...
December 1, 2016: Biointerphases
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