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kinetic control

Yunhui Zhang, Fei Jin, Zhengtao Shen, Rod Lynch, Abir Al-Tabbaa
The intensive use of methyl tert-butyl ether (MTBE) as a gasoline additive has resulted in serious environmental problems due to its high solubility, volatility and recalcitrance. The feasibility of permeable reactive barriers (PRBs) with ZSM-5 type zeolite as a reactive medium was explored for MTBE contaminated groundwater remediation. Batch adsorption studies showed that the MTBE adsorption onto ZSM-5 follows the Langmuir model and obeys the pseudo-second-order model with an adsorption capacity of 53.55 mg g-1...
January 10, 2018: Journal of Hazardous Materials
Daniel Olivo-Alanis, Refugio Bernardo Garcia-Reyes, Luis H Alvarez, Alcione Garcia-Gonzalez
Lawsone redox (LQ) mediator was covalently bound to granular activated carbon (GAC) by Fischer esterification. A high LQ adsorption capacity on GAC was achieved (∼230 mg/g), and desorption studies showed strong chemical stability. Furthermore, kinetic experiments with solid-phase redox mediator (RM) and their controls (soluble RM, GAC and anaerobic sludge) were tested for decolorization of congo red dye at initial concentration of 175 mg/L. Benzidine, a by-product of complete congo red reduction, was also measured by HPLC analysis along the kinetic experiments...
January 9, 2018: Journal of Hazardous Materials
Anh-Vu Do, Sean M Geary, Dongrim Seol, Phillip Tobias, Daniel Carlsen, Nattawut Leelakanok, James A Martin, Aliasger K Salem
Melanoma is an incurable disease for which alternative treatments to chemotherapy alone are sought. Here, using a melanoma model, we investigated the antitumor potential of combining ultrasound (US) with poly(lactic-co-glycolic acid) (PLGA) microspheres loaded with doxorubicin (DOX). The aim was to achieve synergistic tumoricidal activity through direct and indirect US-mediated damage of tumor cells combined with sustained and potentially controllable release (when combined with US) of DOX from microspheres...
January 15, 2018: International Journal of Pharmaceutics
Lei Li, Feijun Wang, Ziqiang Shao
A biomass-based magnetic fluorescent nanoparticle (MFNPs) was successively in situ synthesized via a one-step high-gravity approach, which constructed by a magnetic core of Fe3O4 nanoparticles, the fluorescent marker of carbon dots (CDs), and shells of chitosan (CS). The obtained MFNPs had a 10 nm average diameter and narrow particle size distribution, low cytotoxicity, superior fluorescent emission and superparamagnetic properties. The encapsulating and release 5-fluorouracil experiments confirmed that the introduction of CS/CDs effectively improved the drug loading capacity...
March 15, 2018: Carbohydrate Polymers
Jamal Chabbi, Oumayma Jennah, Nadia Katir, Mohamed Lahcini, Mosto Bousmina, Abdelkrim El Kadib
Temporal release of synergistic and/or complementary chemicals (e.g.: drugs) is recognized as extremely challenging because of their frequently intertwined kinetic delivery and presently, straightforward concepts enabling to circumvent this bottleneck are missing in the open literature. In this framework, we report herein on aldehyde-functionalized, transparent and flexible chitosan-montmorillonite hybrid films that act as a new generation of eco-friendly, controlled-chemical release bioplastics. These dynamically-assembled nanomaterials are designed by a ternary assembly from biowaste derived chitin biopolymer, aromatic aldehydes and layered clay nanoparticles...
March 1, 2018: Carbohydrate Polymers
Sandra Döpking, Craig P Plaisance, Daniel Strobusch, Karsten Reuter, Christoph Scheurer, Sebastian Matera
In the last decade, first-principles-based microkinetic modeling has been developed into an important tool for a mechanistic understanding of heterogeneous catalysis. A commonly known, but hitherto barely analyzed issue in this kind of modeling is the presence of sizable errors from the use of approximate Density Functional Theory (DFT). We here address the propagation of these errors to the catalytic turnover frequency (TOF) by global sensitivity and uncertainty analysis. Both analyses require the numerical quadrature of high-dimensional integrals...
January 21, 2018: Journal of Chemical Physics
Mayur Shirish Jain, Rohit Jambhulkar, Ajay S Kalamdhad
Composting is an efficient technology to reduce pathogenic bodies and stabilize the organic matter in organic wastes. This research work investigates an effect of biochar as amendment to improve the composting efficiency and its effect on degradation kinetics, physical and nutritional properties. Biochar (2.5, 5 and 10% (w/w)) were added into a mixture of Hydrilla verticillata, cow dung and sawdust having ratio of 8:1:1 (control), respectively. Biochar addition resulted in advanced thermophilic temperatures (59 °C) and could improve the physical properties of composting process...
January 9, 2018: Bioresource Technology
L D Bogachus, M D Bellin, A Vella, R P Robertson
Context: Total pancreatectomy and intrahepatic islet autotransplantation (TP/IAT) is performed to alleviate severe abdominal pain, avoid narcotic use, maintain islet function, and avoid diabetes in patients with chronic pancreatitis. However, many TP/IAT recipients complain of post-prandial hypoglycemia. Objective: This study was designed to discover mechanisms of this problem. Design: Participants consumed a triple-isotope mixed meal. Setting: Hospital research unit...
January 17, 2018: Journal of Clinical Endocrinology and Metabolism
Adam S Lepley, Christopher M Kuenze
OBJECTIVE:   To evaluate the current evidence concerning kinematic and kinetic strategies adopted during dynamic landing tasks by patients with anterior cruciate ligament reconstruction (ACLR). DATA SOURCES:   PubMed, Web of Science. STUDY SELECTION:   Original research articles that evaluated kinematics or kinetics (or both) during a landing task in those with a history of ACLR were included. DATA EXTRACTION:   Methodologic quality was assessed using the modified Downs and Black checklist...
January 19, 2018: Journal of Athletic Training
Fumihito Saitow, Masatoshi Nagano, Hidenori Suzuki
Outputs from the cerebellar nuclei (CN) are important for generating and controlling movement. The activity of CN neurons is controlled not only by excitatory inputs from mossy and climbing fibers and by γ-aminobutyric acid (GABA)-based inhibitory transmission from Purkinje cells in the cerebellar cortex but is also modulated by inputs from other brain regions, including serotonergic fibers that originate in the dorsal raphe nuclei. We examined the modulatory effects of serotonin (5-HT) on GABAergic synapses during development, using rat cerebellar slices...
January 19, 2018: Cerebellum
Joakim Bjerketorp, Wilfred F M Röling, Xin-Mei Feng, Armando Hernández Garcia, Hermann J Heipieper, Sebastian Håkansson
Chlorophenols are widespread and of environmental concern due to their toxic and carcinogenic properties. Development of less costly and less technically challenging remediation methods are needed; therefore, we developed a formulation based on micronized vermiculite that, when air-dried, resulted in a granular product containing the 4-chlorophenol (4-CP)-degrading Gram-positive bacterium Arthrobacter chlorophenolicus A6. This formulation and stabilization method yielded survival rates of about 60% that remained stable in storage for at least 3 months at 4 °C...
January 18, 2018: Applied Microbiology and Biotechnology
Oleg Buller, Hong Wang, Wenchong Wang, Lifeng Chi, Andreas Heuer
The pre-patterning of a substrate to create energetically more attractive or repulsive regions allows one to generate a variety of structures in physical vapor deposition experiments. A particularly interesting structure is generated if the energetically attractive region forms a rectangular grid. For specific combinations of the particle flux, the substrate temperature and the lattice size it is possible to generate exactly one cluster per cell, giving rise to nucleation control. Here, we show that the experimental observations of nucleation control can be very well understood from a theoretical perspective...
January 19, 2018: Physical Chemistry Chemical Physics: PCCP
Ron Amon, Shani Leviatan Ben-Arye, Limor Engler, Hai Yu, Noha Lim, Ludmilla Le Berre, Kristina M Harris, Mario R Ehlers, Stephen E Gitelman, Xi Chen, Jean-Paul Soulillou, Vered Padler-Karavani
Humans have circulating antibodies against diverse glycans containing N-glycolylneuraminic acid (Neu5Gc) due to function-loss mutation of the CMAH gene. This xenogenic non-human carbohydrate is abundant in red meat, xenografts and biotherapeutics. Low levels of diet-derived Neu5Gc is also present on normal human endothelial cells, and together with anti-Neu5Gc antibodies could potentially mediate "xenosialitis" chronic-inflammation. Rabbit anti-human thymocyte globulin (ATG) is a drug containing polyclonal IgG glycoproteins commonly used as an immunosuppressant in human transplantation and autoimmune diseases...
December 22, 2017: Oncotarget
Francisco Vega Reyes, Antonio Lasanta, Andrés Santos, Vicente Garzó
The dynamical properties of a tracer or impurity particle immersed in a host gas of inelastic and rough hard spheres in the homogeneous cooling state is studied. Specifically, the breakdown of energy equipartition as characterized by the tracer/host ratios of translational and rotational temperatures is analyzed by exploring a wide spectrum of values of the control parameters of the system (masses, moments of inertia, sizes, and coefficients of restitution). Three complementary approaches are considered. On the theoretical side, the Boltzmann and Boltzmann-Lorentz equations (both assuming the molecular chaos ansatz) are solved by means of a multitemperature Maxwellian approximation for the velocity distribution functions...
November 2017: Physical Review. E
E J Rugeles, Sebastian Ujevic, S A Vitiello
Properties of helium atoms in the solid phase are investigated using the multiweight diffusion Monte Carlo method. Two different importance function transformations are used in two series of independent calculations. The kinetic energy is estimated for both the solid and liquid phases of ^{4}He. We estimate the melting and freezing densities, among other properties of interest. Our estimates are compared with experimental values. We discuss why walkers biased by two distinctly different guiding functions do not lead to noticeable changes in the reported results...
October 2017: Physical Review. E
Vladimir P Zhdanov
mRNA delivery into cells forms the basis for one of the new and promising ways to treat various diseases. Among suitable carriers, lipid nanoparticles (LNPs) with a size of about 100 nm are now often employed. Despite high current interest in this area, the understanding of the basic details of LNP-mediated mRNA delivery and function is limited. To clarify the kinetics of mRNA release from LNPs, the author uses three generic models implying (i) exponential, (ii) diffusion-controlled, and (iii) detachment-controlled kinetic regimes, respectively...
October 2017: Physical Review. E
Bartłomiej Dybiec, Ewa Gudowska-Nowak, Igor M Sokolov
We investigate the distribution of potential and kinetic energy in stationary states of the linearly damped stochastic oscillator driven by Lévy noises. In the long time limit distributions of kinetic and potential energies of the oscillator follow the power-law asymptotics and do not fulfill the equipartition theorem. The partition of the mechanical energy is controlled by the damping coefficient. In the limit of vanishing damping a stochastic analog of the equipartition theorem can be proposed, namely, the statistical properties of potential and kinetic energies attain distributions characterized by the same widths...
October 2017: Physical Review. E
Meital Harel, Haim Taitelbaum
The temperature effect on the dynamics and geometry of a mercury droplet (∼150 μm) spreading on a silver substrate (4000 Å) was studied. The system temperature was controlled by a heating stage in the temperature range of -15 °C < T < 25 °C, and the spreading process was monitored using an optical microscope. We studied the wetting dynamics (droplet radius and velocity) as a function of temperature. We found that for all studied temperatures, the spreading radius R(t) grows linearly with time, with a velocity value depending on temperature...
December 2017: Physical Review. E
D Monteoliva, L Diambra
We use information theory to study the information transmission through a simple gene cascade where the product of an unregulated gene regulates the expression activity of a cooperative genetic switch. While the input signal is provided by the upstream gene with two states, we consider that the expression of downstream gene is controlled by a cis-regulatory system with three binding sites for the regulator product, which can bind cooperatively. By computing exactly the associated probability distributions, we estimate information transmission thought the mutual information measure...
July 2017: Physical Review. E
Patrick Oswald, Jordi Ignés-Mullol
The performance of light-controlled liquid crystal anchoring surfaces depends on the nature of the photosensitive moieties and on the concentration of spacer units. Here, we study the kinetics of photosensitive liquid crystal cells that incorporate an azobenzene-based self-assembled monolayer. We characterize the photoinduced homeotropic-to-planar transition and the subsequent reverse relaxation in terms of the underlying isomerization of the photosensitive layer. We show that the response time can be precisely adjusted by tuning the lateral packing of azobenzene units by means of inert spacer molecules...
September 2017: Physical Review. E
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