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Fluid kinetics

H Saari, E Lisitsyna, K Rautaniemi, T Rojalin, L Niemi, O Nivaro, T Laaksonen, M Yliperttula, E Vuorimaa-Laukkanen
In response to physiological and artificial stimuli, cells generate nano-scale extracellular vesicles (EVs) by encapsulating biomolecules in plasma membrane-derived phospholipid envelopes. These vesicles are released to bodily fluids, hence acting as powerful endogenous mediators in intercellular signaling. EVs provide a compelling alternative for biomarker discovery and targeted drug delivery, but their kinetics and dynamics while interacting with living cells are poorly understood. Here we introduce a novel method, fluorescence lifetime imaging microscopy (FLIM) to investigate these interaction attributes...
June 12, 2018: Journal of Controlled Release: Official Journal of the Controlled Release Society
Renata Kuras, Edyta Reszka, Edyta Wieczorek, Ewa Jablonska, Jolanta Gromadzinska, Beata Malachowska, Lucyna Kozlowska, Magdalena Stanislawska, Beata Janasik, Wojciech Wasowicz
The present observation based research was designed to evaluate the influence of occupational human exposure to metallic mercury (Hg°) vapor on the biomarkers of selenium status involved in the antioxidant defense system. For this purpose we determined Hg and selenium (Se) concentrations in body fluids, the markers of antioxidant effect measured as an activity of Se-dependent enzymes (red blood cell and plasma glutathione peroxidase: GPx1-RBC and GPx3-P), concentration of selenoprotein P in the plasma (SeP-P) and total antioxidant activity in the plasma (TAA-P) in 131 male workers from a chloralkali plant exposed to Hg° and 67 non-exposed males (control group)...
September 2018: Journal of Trace Elements in Medicine and Biology
Anatoly Dmitrievich Rakhel
A phenomenological equation of state is constructed for fluid aluminum to study thermodynamic consequences of the metal-nonmetal transition occurring in the fluid on the thermal expansion. It is demonstrated that the existing experimental data clearly indicate the isochores plotted in the internal energy-pressure plane are straight lines. Based on this fact and some general thermodynamic relations it is shown that the equation of state must have the Mie-Grüneisen-Debye form in this case. This means that such concepts as the cold curve, the Grüneisen coefficient, and the Debye temperature can be applied to the fluid state...
June 12, 2018: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Xubin Wang, Linlin Wang, Xiaopeng Chen, Dan Zhou, Han Xiao, Xiaojie Wei, Jiezhen Liang
A heterogeneous catalyst (ZnO/SFCCR) composed of ZnO supported on spent fluid cracking catalyst by wet impregnation was synthesized and applied to the esterification of colophony acids with methanol under subcritical CO2 conditions. The catalyst was characterized by SEM-EDS, BET, ICP, FTIR, XRD and Py-IR. An experimental set-up involving a new injection technique was designed to promote the heterogeneous methyl esterification, and the subcritical CO2 played a role in auxiliary acid catalysis (a pH range of 3...
May 2018: Royal Society Open Science
Yingchuan Peng, Kangxu Wang, Wenxi Fu, Chengwang Sheng, Zhaojun Han
Double stranded RNAs (dsRNA) degrading nuclease is responsible for the rapid degradation of dsRNA molecules, and thus accounts for variations in RNA interference (RNAi) efficacy among insect species. Here, the biochemical properties and tissue-specific activities of dsRNA degrading nucleases in four insects ( Spodoptera litura, Locusta migratoria, Periplaneta americana , and Zophobas atratus ) from different orders were characterized using a modified assay method. The results revealed that all insect dsRNA degrading nucleases tested showed high activity in alkaline environments at optimal Mg2+ concentrations and elevated temperatures...
2018: Frontiers in Physiology
Tasneem Kausar, Shahid M Nayeem
GDF-5 mediated signal transduction regulating chondrogenesis and skeletogenesis involves three different type-I receptors viz. Act-RI, BMPRIA and BMPRIB. BMPRIA and BMPRIB generally shows temporal and spatial co-expression but some spatially different expression pattern has also been observed. BMPRIA receptor is the key receptor implicated in BMP signalling during osteogenesis and is expressed in osteoblasts during the course of bone formation. However, BMPRIB appears to be primarily expressed in mesenchymal pre-cartilage condensations and also found in differentiated osteoblast and chondrocytes...
May 26, 2018: Biophysical Chemistry
Kirsten Harth, Torsten Trittel, Sandra Wegner, Ralf Stannarius
Granular gases as dilute ensembles of particles in random motion are at the basis of elementary structure-forming processes in the Universe, involved in many industrial and natural phenomena, and also excellent models to study fundamental statistical dynamics. The essential difference to molecular gases is the energy dissipation in particle collisions. Its most striking manifestation is the so-called granular cooling, the gradual loss of mechanical energy E(t) in the absence of external excitation. We report an experimental study of homogeneous cooling of three-dimensional granular gases in microgravity...
May 25, 2018: Physical Review Letters
Sher Bahadar Khan, Khalid A Alamry, Nedaa A Alyahyawi, Abdullah M Asiri
Background: The intercalation of an antibiotic drug, cefadroxil (CD), into the inter-gallery of Zn, Al nitrate-layered double hydroxide (LDH) was accomplished using a co-precipitation method. This formed a nanostructured organic-inorganic hybrid material that can be exploited for the preparation of a controlled release formulation. Materials and methods: The drug-LDH nanohybrid was characterized by using field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR) thermogravimetric (TG) analysis, X-ray powder diffraction (XRD) and UV-visible (UV-vis) absorption spectroscopy, which confirmed the intercalation process...
2018: International Journal of Nanomedicine
Shimaa A Mousa, Pradeep K Malik, Atul P Kolte P Kolte, Raghavendra Bhatta, Shigemitsu Kasuga, Yutaka Uyeno
Objective: Ensiling of tannin-rich fruit byproducts (FB) involves quantitative and qualitative changes in the tannins, which would consequently change the rumen fermentation characteristics. This study aimed to evaluate whether ensiled FBs are effective in mitigating methane emission from ruminants by conducting in vitro assessments. Methods: Fruit byproducts (grape pomace, wild grape pomace, and persimmon skin) were collected and subjected to four-week ensiling by Lactobacillus buchneri inoculant...
May 31, 2018: Asian-Australasian Journal of Animal Sciences
Assaf Bar, Emil Ruvinov, Smadar Cohen
Osteochondral defects (OCDs) are conditions affecting both cartilage and the underlying bone. Since cartilage is not spontaneously regenerated, our group has recently developed a strategy of injecting bioactive alginate hydrogel into the defect for promoting endogenous regeneration of cartilage via presentation of affinity-bound transforming growth factor β1 (TGF-β1). As in vivo model systems often provide only limited insights regarding the mechanism behind regeneration processes, here we describe a novel flow bioreactor for the in vitro modeling of the OCD microenvironment, designed to promote cell recruitment from the simulated bone marrow compartment into the hydrogel, under physiological flow conditions...
June 5, 2018: Biotechnology and Bioengineering
Lilian C Johnson, Benjamin J Landrum, Roseanna N Zia
Yield of colloidal gels during start-up of shear flow is characterized by an overshoot in shear stress that accompanies changes in network structure. Prior studies of yield of reversible colloidal gels undergoing strong flow model the overshoot as the point at which network rupture permits fluidization. However, yield under weak flow, which is of interest in many biological and industrial fluids shows no such disintegration. The mechanics of reversible gels are influenced by bond strength and durability, where ongoing rupture and re-formation impart aging that deepens kinetic arrest [Zia et al...
June 5, 2018: Soft Matter
Indranil Dasgupta, David Keane, Elizabeth Lindley, Ihab Shaheen, Kay Tyerman, Franz Schaefer, Elke Wühl, Manfred J Müller, Anja Bosy-Westphal, Hans Fors, Jovanna Dahlgren, Paul Chamney, Peter Wabel, Ulrich Moissl
BACKGROUND: Bioimpedance spectroscopy (BIS) with a whole-body model to distinguish excess fluid from major body tissue hydration can provide objective assessment of fluid status. BIS is integrated into the Body Composition Monitor (BCM) and is validated in adults, but not children. This study aimed to (1) assess agreement between BCM-measured total body water (TBW) and a gold standard technique in healthy children, (2) compare TBW_BCM with TBW from Urea Kinetic Modelling (UKM) in haemodialysis children and (3) investigate systematic deviation from zero in measured excess fluid in healthy children across paediatric age range...
June 4, 2018: Pediatric Nephrology: Journal of the International Pediatric Nephrology Association
Mayank Srivastava, Dipanjan Chakraborty
We revisit the effective parameter description of hot Brownian motion-a scenario where a colloidal particle is kept at an elevated temperature than the ambient fluid. Due to the time scale separation between heat diffusion and particle motion, a stationary halo of hot fluid is carried along with the particle resulting in a spatially varying comoving temperature and viscosity profile. The resultant Brownian motion in the overdamped limit can be well described by a Langevin equation with effective parameters such as effective temperature THBM and friction coefficient ζHBM that quantifies the thermal fluctuations and the diffusivity of the particle...
May 28, 2018: Journal of Chemical Physics
K G S H Gunawardana, Xueyu Song
The first order curvature correction to the crystal-liquid interfacial free energy is calculated using a theoretical model based on the interfacial excess thermodynamic properties. The correction parameter (δ), which is analogous to the Tolman length at a liquid-vapor interface, is found to be 0.48 ± 0.05 for a Lennard-Jones (LJ) fluid. We show that this curvature correction is crucial in predicting the nucleation barrier when the size of the crystal nucleus is small. The thermodynamic driving force (Δμ) corresponding to available simulated nucleation conditions is also calculated by combining the simulated data with a classical density functional theory...
May 28, 2018: Journal of Chemical Physics
Hanan Fael, Clara Ràfols, A Levent Demirel
Poly(2-ethyl-2-oxazoline) (PEOX), a biocompatible polymer considered as pseudo polypeptide, was introduced as a potential alternative to the commonly used polymer, poly(vinylpyrrolidone) (PVP) for the preparation of solid dispersion with a poorly soluble drug. Glipizide (GPZ), a BCS class II model drug, was selected for solubility and dissolution rate study. GPZ-polymer solid dispersions and physical mixtures were characterized and investigated by X-Ray diffractometry, differential scanning calorimetry, scanning electron microscopy, and Fourier transform infrared spectroscopy...
May 31, 2018: Journal of Pharmaceutical Sciences
Nathania J Leong, Dharmini Mehta, Victoria M McLeod, Brian D Kelly, Rashmi Pathak, David J Owen, Christopher Jh Porter, Lisa M Kaminskas
PEGylated polylysine dendrimers have demonstrated potential as inhalable drug delivery systems that can improve the treatment of lung cancers. Their treatment potential may be enhanced by developing constructs that display prolonged lung retention, together with good systemic absorption, the capacity to passively target lung tumours from the blood and highly selective, yet rapid liberation in the tumour microenvironment. This study sought to characterise how the nature of cathepsin B cleavable peptide linkers, used to conjugate doxorubicin to a PEGylated (PEG570) G4 polylysine dendrimer, affect drug liberation kinetics and intravenous and pulmonary pharmacokinetics in rats...
May 28, 2018: Journal of Pharmaceutical Sciences
Mustafa Bilici, Adem Zengin, Elvan Ekmen, Demet Cetin, Nahit Aktas
Magnetic molecularly imprinted nanoparticles were prepared through surface-initiated reversible addition fragmentation chain transfer polymerization by using metronidazole as a template. The molecularly imprinted magnetic nanoparticles were characterized by attenuated total reflection Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, X-ray diffraction and vibrating sample magnetometry. The adsorption characteristics were also investigated and the kinetics of the adsorption of metronidazole on the imprinted nanoparticles were described by the second-order kinetic model with the short equilibrium adsorption time (30 min)...
May 29, 2018: Journal of Separation Science
Susruta Manivannan, Milan Makwana, Aminul Islam Ahmed, Malik Zaben
Traumatic brain injury (TBI) poses a major public health problem on a global scale. Its burden results from high mortality and significant morbidity in survivors. This stems, in part, from an ongoing inadequacy in diagnostic and prognostic indicators despite significant technological advances. Traumatic axonal injury (TAI) is a key driver of the ongoing pathological process following TBI, causing chronic neurological deficits and disability. The science underpinning biomarkers of TAI has been a subject of many reviews in recent literature...
May 18, 2018: Clinical Neurology and Neurosurgery
Sheldon Chen
Ascertaining a patient's kidney function is more difficult to do when the serum creatinine is changing than when it is stable. To accomplish the task, various kinetic clearance equations have been developed. To date, however, none of them have allowed for ongoing changes to the creatinine's volume of distribution. These diluting or concentrating effects on the [creatinine] can greatly impact the accuracy of kidney function assessment. Described herein is a model of creatinine kinetics that also accommodates volume changes...
May 22, 2018: Mathematical Biosciences
Mengkai Li, Mengyu Hao, Laxiang Yang, Hong Yao, James R Bolton, Ernest R Blatchley, Zhimin Qiang
The vacuum-ultraviolet/ultraviolet/chlorine (VUV/UV/chlorine) process, with a VUV/UV mercury lamp used as the light source, was found to be a highly efficient advanced oxidation process (AOP) in a previous study. Hence, its application feasibility for trace organic pollutant removal from drinking water becomes attractive. In this work, a bench-scale mini-fluidic VUV/UV photoreaction system was used to determine the degradation kinetics of sulfamethazine (SMN), a model sulfonamide antibiotic frequently detected with trace levels in aquatic environments...
May 24, 2018: Environmental Science & Technology
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