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Fluid kinetics

Jessy Lauer, João Paulo Vilas-Boas, Annie Hélène Rouard
Aquatic exercises are widely implemented into rehabilitation programs. However, both evaluating their mechanical demands on the musculoskeletal system and designing protocols to provide progressive loading are difficult tasks. This study reports for the first time shoulder joint kinetics and dynamics during underwater forward arm elevation performed at speeds ranging from 22.5 to 90°/s. Net joint moments projected onto anatomical axes of rotation, joint power, and joint work were calculated in 18 participants through a novel approach coupling numerical fluid flow simulations and inverse dynamics...
February 9, 2018: Journal of Biomechanics
Dorota Wójcik-Pastuszka, Iwona Golonka, Andrzej Drys, Jobst B Mielck, Maria Twarda, Witold Musiał
BACKGROUND: Gastric residence time is the key factor affecting the bioavailability of active pharmaceutical ingredients absorbed mainly through the gastric mucous membrane and influencing the local activity of some drugs. OBJECTIVES: The aim of this study was the development of a new composition of non-effervescent floating tablets and the evaluation of the effect of an anionic polymer and compressive force on the floating properties and release characteristics of tablets containing a model alkaline drug, chlorhexidine (CHX)...
December 2017: Advances in Clinical and Experimental Medicine: Official Organ Wroclaw Medical University
Clare Rusbridge, Francisco J Salguero, Monique Antoinette David, Kiterie M E Faller, Jose T Bras, Rita J Guerreiro, Angela C Richard-Londt, Duncan Grainger, Elizabeth Head, Sebastian G P Brandner, Brian Summers, John Hardy, Mourad Tayebi
Many of the molecular and pathological features associated with human Alzheimer disease (AD) are mirrored in the naturally occurring age-associated neuropathology in the canine species. In aged dogs with declining learned behavior and memory the severity of cognitive dysfunction parallels the progressive build up and location of Aβ in the brain. The main aim of this work was to study the biological behavior of soluble oligomers isolated from an aged dog with cognitive dysfunction through investigating their interaction with a human cell line and synthetic Aβ peptides...
2018: Frontiers in Aging Neuroscience
Chao Pi, Ting Feng, Jing Liang, Hao Liu, Dongmei Huang, Chenglin Zhan, Jiyuan Yuan, Robert J Lee, Ling Zhao, Yumeng Wei
Felodipine (FD) has been widely used in anti-hypertensive treatment. However, it has extremely low aqueous solubility and poor bioavailability. To address these problems, FD hollow microspheres as multiple-unit dosage forms were synthesized by a solvent diffusion evaporation method. Particle size of the hollow microspheres, types of ethylcellulose (EC), amounts of EC, polyvinyl pyrrolidone (PVP) and FD were investigated based on an orthogonal experiment of three factors and three levels. In addition, the release kinetics in vitro and pharmacokinetics in beagle dogs of the optimized FD hollow microspheres was investigated and compared with Plendil (commercial FD sustained-release tablets) as a single-unit dosage form...
February 9, 2018: International Journal of Biological Macromolecules
Reza Abazari, Ali Reza Mahjoub, Alexandra M Z Slawin, Cameron L Carpenter-Warren
In this study, we have reported a biocompatible metal-organic framework (MOF) with ultra-high surface area, which we have shown to have uses as both a cancer treatment delivery system and for environmental applications. Using a sonochemical approach, highly flexible organic H3BTCTB and ditopic 4,4'-BPDC ligands, along with modulators of acetic acid and pyridine were combined to prepare a Zn(II)-based metal-organic framework, DUT-32, [Zn4O(BPDC)(BTCTB)4/3(DEF)39.7(H2O)11.3]. Powder X-ray diffraction (PXRD), field-emission scanning electron microscopy (FE-SEM), and Fourier transform infrared spectroscopy (FTIR) were used to characterize, the particle size, shape, and structure of the DUT-32...
April 2018: Ultrasonics Sonochemistry
Stevan M Cokic, Radu C Duca, Jan De Munck, Peter Hoet, Bart Van Meerbeek, Mario Smet, Lode Godderis, Kirsten L Van Landuyt
OBJECTIVE: Accurate knowledge of the quantity of released monomers from composites is important. To evaluate the elution of monomers, polymerized composites are typically immersed in an extraction solvent. The objective was to determine whether the volume of extraction solvent and the immersion time influences monomer leachability from dental composite materials. METHODS: Composite disks of two commercial composites, (Filtek Supreme XTE, 3M ESPE and G-aenial Universal Flo, GC) were prepared...
February 8, 2018: Dental Materials: Official Publication of the Academy of Dental Materials
C L O Leo-Penu, J Picard, L A Fitzpatrick, A J Parker
The effects on rumen kinetics after feed and water had been deprived for 72 hr were studied using four fistulated Bos indicus steers. The animals were assigned in a 2 × 4 crossover design with two treatments: feed and water ad libitum (control) and no feed and water for 72 hr (deprived) with four steers per treatment over two time periods. Feed and water deprivation caused decreases in the numbers of cellulolytic bacteria (1.4 vs. 0.4 cfu × 106 /ml; p = .001), live (23.7 vs. 0.8 × 109 /ml; p = ...
February 9, 2018: Journal of Animal Physiology and Animal Nutrition
Roberto Biondi, Stefano Brancorsini, Giulia Poli, Maria Giulia Egidi, Enrico Capodicasa, Livio Bottiglieri, Sandro Gerli, Eleonora Brillo, Gian Carlo Di Renzo, Dragos Cretoiu, Romeo Micu, Nicolae Suciu
Hydroxyl radical (.OH) is highly reactive, and therefore very short-lived. Finding new means to accurately detect .OH, and testing the ability of known .OH scavengers to neutralize them in human biological fluids would leverage our ability to more effectively counter oxidative (.OH) stress-mediated damage in human diseases. To achieve this, we pursued the evaluation of secondary products resulting from .OH attack, using a detection system based on Fenton reaction-mediated D-phenylalanine (D-Phe) hydroxylation...
May 1, 2018: Talanta
Barbara Pavan, Alessandro Dalpiaz, Luca Marani, Sarah Beggiato, Luca Ferraro, Donatella Canistro, Moreno Paolini, Fabio Vivarelli, Maria C Valerii, Antonietta Comparone, Luigia De Fazio, Enzo Spisni
Geraniol is a natural monoterpene showing anti-inflammatory, antioxidant, neuroprotective and anticancer effects. No pharmacokinetic and bioavailability data on geraniol are currently available. We therefore performed a systematic study to identify the permeation properties of geraniol across intestinal cells, and its pharmacokinetics and bioavailability after intravenous and oral administration to rats. In addition, we systematically investigated the potential hepatotoxic effects of high doses of geraniol on hepatic phase I, phase II and antioxidant enzymatic activities and undertook a hematochemical analysis on mice...
2018: Frontiers in Pharmacology
Deborah Huber, Ali Oskooei, Xavier Casadevall I Solvas, Andrew deMello, Govind V Kaigala
Hydrodynamic phenomena are ubiquitous in living organisms and can be used to manipulate cells or emulate physiological microenvironments experienced in vivo. Hydrodynamic effects influence multiple cellular properties and processes, including cell morphology, intracellular processes, cell-cell signaling cascades and reaction kinetics, and play an important role at the single-cell, multicellular, and organ level. Selected hydrodynamic effects can also be leveraged to control mechanical stresses, analyte transport, as well as local temperature within cellular microenvironments...
February 8, 2018: Chemical Reviews
Wai-Ming Yau, Robert Tycko
Aggregation of amyloid-β (Aβ) peptides in brain tissue leads to neurodegeneration in Alzheimer's disease (AD). Regardless of the kinetics or detailed mechanisms of Aβ aggregation, aggregation can only occur if Aβ concentrations exceed their local equilibrium solubility values. We propose that excess Aβ peptides can be removed from supersaturated solutions, including solutions in biological fluids, by the addition of hydrogels that are seeded with Aβ fibril fragments. Fibril growth within the hydrogels then sequesters excess peptides until equilibrium concentrations are reached...
February 8, 2018: Protein Science: a Publication of the Protein Society
Rohit Bisht, Ilva D Rupenthal, Sreevalsan Sreebhavan, Jagdish K Jaiswal
Connexin43 mimetic peptide (Cx43MP) has been intensively investigated for its therapeutic effect in the management of inflammatory eye conditions, spinal cord injury, wound healing and ischemia-induced brain damage. Here, we report on a validated stability-indicating reversed-phase high performance liquid chromatography (RP-HPLC) method for the quantification of Cx43MP under stress conditions. These included exposure to acid/base, light, oxidation and high temperature. In addition, the degradation kinetics of the peptide were evaluated in bovine vitreous and drug-free human plasma at 37 °C...
December 2017: Journal of Pharmaceutical Analysis
Matteo Minelli, Giulio C Sarti
The transport of gases in glassy polymeric membranes has been analyzed by means of a fundamental approach based on the nonequilibrium thermodynamic model for glassy polymers (NET-GP) that considers the penetrant chemical potential gradient as the actual driving force of the diffusional process. The diffusivity of a penetrant is thus described as the product of a purely kinetic quantity, the penetrant mobility, and a thermodynamic factor, accounting for the chemical potential dependence on its concentration in the polymer...
February 3, 2018: Membranes
C Schaefer
Fluids with spatial density variations of single or mixed molecules play a key role in biophysics, soft matter, and materials science. The fluid structures usually form via spinodal decomposition or nucleation following an instantaneous destabilization of the initially disordered fluid. However, in practice, an instantaneous quench is often not viable, and the rate of destabilization may be gradual rather than instantaneous. In this work we show that the commonly used phenomenological descriptions of fluid structuring are inadequate under these conditions...
January 19, 2018: Physical Review Letters
Vandana Singh, Sneha Joshi, Tulika Malviya
Adequate release of 5-ASA in colon is challenging as it easily permeates at the acidic pH of the upper gastrointestinal tract. Targeting delayed release of 5-ASA at acidic pH, Carboxymethyl cellulose-rosin gum hybrid nanoparticles (CRNP3) with an average size of 267 nm have been crafted through nanoprecipitation method. CRNP3 was extensively characterized using Fourier Transform Spectroscopy (FTIR), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and particle size analysis based on dynamic light scattering...
January 30, 2018: International Journal of Biological Macromolecules
Velu Nair, D N Karan, C S Makhani
Management of victim of radiation injury poses a wide spectrum of challenges to the health care provider starting with the evaluation of the damage, the kind of hospitalization and treatment and the regular monitoring of the patient. Undesirable clinical outcomes are probable if prodromal stage evolves rapidly and is severe. Critical systems like neurovascular, gastrointestinal, haematopoietic and cutaneous are afflicted in Acute Radiation Syndrome. Three main elements which are essential for assessment of prognosis and selection of treatment are vomiting onset time, kinetics of depletion of lymphocyte, and chromosome abnormalities...
October 2017: Medical Journal, Armed Forces India
Baris U Agar, James A Sloand
BACKGROUND: Incremental dialysis utilizes gradually increasing dialysis doses in response to declines in residual kidney function, and it is the preferred renal replacement therapy for patients who have just transitioned to end-stage renal disease (ESRD). Incremental peritoneal dialysis (PD) may impose fewer restrictions on patients' lifestyle, help attenuate lifetime peritoneal and systemic exposure to glucose and its degradation products, and minimize connections that could compromise the sterile fluid path...
January 31, 2018: Peritoneal Dialysis International: Journal of the International Society for Peritoneal Dialysis
Tarcísio Jorge Leitão, Jaime Aparecido Cury, Livia Maria Andaló Tenuta
Dental biofilm bacteria can bind calcium ions and release them during a pH drop, which could decrease the driving force for dental demineralization (i.e. hydroxyapatite dissolution) occurring at reduced pHs. However, the kinetics of this binding and release is not completely understood. Here we validated a method to evaluate the kinetics of calcium binding and release to/from Streptococcus mutans, and estimated the importance of this reservoir as a source of ions. The kinetics of calcium binding was assessed by measuring the amount of bound calcium in S...
2018: PloS One
Vincenzo Guarino, Tania Caputo, Paola Calcagnile, Rosaria Altobelli, Christian Demitri, Luigi Ambrosio
Herein, we propose the fabrication of a new carrier with core/shell structure-inner core of cellulose acetate (CA) coated by a micrometric layer of chitosan (CS)-fabricated through an integrated process, which combines Electro Dynamic Atomization (EDA) and layer-by-layer (LbL) technique. We demonstrate that CA based microspheres possess a unique capability to relevantly retain the drugs-that is, Ketoprofen Lysinate (KL)-along the gastric tract, while providing a massive release along the intestine. CS shell slightly influences the morphology and water retention under different pH conditions, improving drug encapsulation without compromising drug release kinetics...
January 26, 2018: Journal of Biomedical Materials Research. Part B, Applied Biomaterials
F De Leersnyder, V Vanhoorne, H Bekaert, J Vercruysse, M Ghijs, N Bostijn, M Verstraeten, P Cappuyns, Ivo Van Assche, Y Vander Heyden, E Ziemons, J P Remon, I Nopens, C Vervaet, T De Beer
Although twin screw granulation has already been widely studied in recent years, only few studies addressed the subsequent continuous drying which is required after wet granulation and still suffers from a lack of detailed understanding. The latter is important for optimisation and control and, hence, a cost-effective practical implementation. Therefore, the aim of the current study is to increase understanding of the drying kinetics and the breakage and attrition phenomena during fluid bed drying after continuous twin screw granulation...
January 24, 2018: European Journal of Pharmaceutical Sciences
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