Kinetics Research Papers - Academia.edu (original) (raw)

Batch experiments were carried out to investigate the stoichiometry and kinetics of microbial degradation of toluene under denitrifying conditions. The inoculum originated from a mixture of sludges from sewage treatment plants with... more

Batch experiments were carried out to investigate the stoichiometry and kinetics of microbial degradation of toluene under denitrifying conditions. The inoculum originated from a mixture of sludges from sewage treatment plants with alternating nitrification and denitrification. The culture was able to degrade toluene under anaerobic conditions in the presence of nitrate, nitrite, nitric oxide, or nitrous oxide. No degradation occurred in the absence of Noxides. The culture was also able to use oxygen, but ferric iron could not be used as an electron acceptor. In experiments with 14C-labeled toluene, 34% 4-8% of the carbon was incorporated into the biomass, while 53% 4-10% was recovered as t4CO2, and 6% + 2% remained in the medium as nonvolatile water soluble products. The average consumption of nitrate in experiments, where all the reduced nitrate was recovered as nitrite, was 1.3 :t: 0.2 mg of nitrate-N per mg of toluene. This nitrate reduction accounted for 70% of the electrons donated during the oxidation of toluene. When nitrate was reduced to nitrogen gas, the consumption was 0.7 4-0.2 nag per mg of toluene, accounting for 97% of the donated electrons. Since the ammonia concentration decreased during degradation, dissimilatory reduction of nitrate to ammonia was not the reductive process. The degradation of toluene was modelled by classical Monod kinetics. The maximum specific rate of degradation, k, was estimated to be 0.71 mg toluene per mg of protein per hour, and the Monod saturation constant, Ks, to be 0.2 mg toluene/1. The maximum specific growth rate,/~,~ax, was estimated to be 0.1 per hour, and the yield coefficient, Y, was 0.14 mg protein per mg toluene.

The applicability of a two-parameter Fickian diffusion model for predicting the skin steady-state permeability based on measurements of the transient transport of permeants across the skin was tested. Using five model permeants possessing... more

The applicability of a two-parameter Fickian diffusion model for predicting the skin steady-state permeability based on measurements of the transient transport of permeants across the skin was tested. Using five model permeants possessing different physicochemical properties and pig skin as the model membrane, the skin permeabilities predicted by the two-parameter Fickian diffusion model were compared with the measured skin permeabilities. Results show that the transient skin permeation profiles of the hydrophobic permeants, estradiol, testosterone, and dolichol, across splitthickness pig skin can be modeled adequately by the two-parameter Fickian diffusion model (with constant parameter values), and therefore, that this model can be utilized to shorten the experimental time required to determine the skin permeabilities of these compounds. However, the skin permeabilities of the highly hydrophilic permeants, mannitol and sucrose, predicted by the two-parameter Fickian diffusion model (with constant parameter values) were significantly lower than the experimentally determined values, indicating that the dominant skin pathway of polar permeants within the excised pig skin undergoes significant structural changes during the in vitro diffusion cell studies. Although the skin permeability values determined experimentally using the traditional steady-state method normally correspond to a highly hydrated skin sample, the two-parameter Fickian diffusion model enables an estimation of the skin permeability of the skin membrane at its less-hydrated state (a condition more representative of in vivo and clinical situations). Using the two-parameter Fickian diffusion model and a recently developed skin porous-pathway theory, the effects of skin hydration on the skin porous pathway within the excised pig skin were characterized. Specifically, we found that hydration leads to induction of new pores/reduction of the tortuosity of existing pores within the excised pig skin during the 48 h diffusion cell studies conducted, while the skin average pore radii remain relatively constant ($26 Å ) for up to 48 h. ß

Diurnal activity is characteristic of many toad species, including Bufo granulosus from the Brazilian semi-arid biome called the Caatinga. Because of their patterns of activity, juvenile toads are exposed to hot and dehydrating... more

Diurnal activity is characteristic of many toad species, including Bufo granulosus from the Brazilian semi-arid biome called the Caatinga. Because of their patterns of activity, juvenile toads are exposed to hot and dehydrating conditions. Our investigation focuses on temperature and water relationships, and is based on the prediction that anuran diurnal activity in a semi-arid environment must be associated with morphological, physiological and behavioral traits enhancing thermal tolerances, capacity for performance at high temperatures and water balance. To test specific hypothesis related with this prediction, we investigated postmetamorphic B. granulosus and collected data on thermal tolerances and preferences, thermal safety margins, thermal dependence of locomotor behavior, thermal and kinetic properties of citrate synthase (CS), and skin morphophysiology. This information was compared with additional data from adult conspecifics and adult toads from sympatric species or from species from more moderate environments. We found that juvenile B. granulosus exhibit the highest critical maximum temperature reported for toads (44.2°C) and are well suited to move at high temperatures. However, and in contrast with juveniles of other Bufo species, they do not show thermal preferences in a gradient and appear to hydroregulate more than thermoregulate. The CS of adult and juvenile toads shows typical patterns of thermal sensibility, but the thermal stability of this enzyme is much higher in juveniles than in adult Bufo of any other species studied. The inguinal skin exhibits a complex folding pattern and seems highly specialized for capillary water uptake. Diurnal activity in juvenile B. granulosus is possible given high thermal tolerances, keen ability to detect and uptake water, and avoidance behaviors. Comparative Biochemistry and Physiology, Part A 147 (2007) 647 -657 www.elsevier.com/locate/cbpa ☆ This paper is part of the 3rd special issue of CBP dedicated to The Face of Latin American Comparative Biochemistry and Physiology organized by Marcelo Hermes-Lima (Brazil) and co-edited by Carlos Navas (Brazil), Rene Beleboni (Brazil), Rodrigo Stabeli (Brazil), Tania Zenteno-Savín (Mexico) and the editors of CBP. This issue is dedicated to the memory of two exceptional men, Peter L. Lutz, one of the pioneers of comparative and integrative physiology, and Cicero Lima, journalist, science lover and Hermes-Lima's dad.

Over 1.5 billion people lack the skeletal muscle fast-twitch fibre protein α-actinin-3 due to homozygosity for a common null polymorphism (R577X) in the ACTN3 gene. α-Actinin-3 deficiency is detrimental to sprint performance in elite... more

Over 1.5 billion people lack the skeletal muscle fast-twitch fibre protein α-actinin-3 due to homozygosity for a common null polymorphism (R577X) in the ACTN3 gene. α-Actinin-3 deficiency is detrimental to sprint performance in elite athletes and beneficial to endurance activities. In the human genome, it is very difficult to find single-gene loss-of-function variants that bear signatures of positive selection, yet intriguingly, the ACTN3 null variant has undergone strong positive selection during recent evolution, appearing to provide a survival advantage where food resources are scarce and climate is cold. We have previously demonstrated that α-actinin-3 deficiency in the Actn3 KO mouse results in a shift in fast-twitch fibres towards oxidative metabolism, which would be more "energy efficient" in famine, and beneficial to endurance performance. Prolonged exposure to cold can also induce changes in skeletal muscle similar to those observed with endurance training, and ch...

An extensive programme of experiments was conducted in the former USSR on transfer of radionuclides to a wide range of different agricultural animals. Only a few of these studies were made available in the English language literature or... more

An extensive programme of experiments was conducted in the former USSR on transfer of radionuclides to a wide range of different agricultural animals. Only a few of these studies were made available in the English language literature or taken into account in international reviews of gastrointestinal uptake. The paper gives extended information on Russian research on radionuclide absorption in the gut of farm animals performed in controlled field and laboratory experiments from the 1960s to the current time. The data presented in the paper, together with English language values, will be used to provide recommended values of absorption specifically for farm animals within the revision of the IAEA Handbook of Parameter Values IAEA [International Atomic Energy Agency, 1994. Handbook of Parameter Values for the Prediction of Radionuclide Transfer in Temperate Environments, IAEA technical reports series No. 364. International Atomic Energy Agency, Vienna].

A new kinetic model for the fluid catalytic cracking (FCC) riser is developed. An elementary reaction scheme, for the FCC, based on cracking of a large number of lumps in the form of narrow boiling pseudocomponents is proposed. The... more

A new kinetic model for the fluid catalytic cracking (FCC) riser is developed. An elementary reaction scheme, for the FCC, based on cracking of a large number of lumps in the form of narrow boiling pseudocomponents is proposed. The kinetic parameters are estimated using a semi-empirical approach based on normal probability distribution. The correlation proposed for the kinetic parameters' estimation contains four parameters that depend on the feed characteristics, catalyst activity, and coke forming tendency of the feed. This approach eliminates the need of determining a large number of rate constants required for conventional lumped models. The model seems to be more versatile than existing models and opens up a new dimension for making generic models suitable for the analysis and control studies of FCC units. The model also incorporates catalyst deactivation and two-phase flow in the riser reactor. Predictions of the model compare well with the yield pattern of industrial scale plant data reported in literature. ᭧

Previous research, in which static figures were used, showed that the ability to perceive illusory contours emerges around 7 months of age. However, recently, evidence has suggested that 2-3-month-old infants are able to perceive illusory... more

Previous research, in which static figures were used, showed that the ability to perceive illusory contours emerges around 7 months of age. However, recently, evidence has suggested that 2-3-month-old infants are able to perceive illusory contours when motion information is available . The present study was aimed at investigating whether even newborns might perceive kinetic illusory contours when a motion easily detected by the immature newborn's visual system (i.e. stroboscopic motion) is used. In Experiment 1, using a preference looking technique, newborns' perception of kinetic illusory contours was explored using a Kanizsa figure in a static and in a kinetic display. The results showed that newborns manifest a preference for the illusory contours only in the kinetic, but not in the static, condition. In Experiment 2, using an habituation technique, newborns were habituated to a moving shape that was matched with the background in terms of random-texture-surface; thus the recovery of the shape was possible relying only on kinetic information. The results showed that infants manifested a novelty preference when presented with luminance-defined familiar and novel shapes. Altogether these findings provide evidence that motion enhances (Experiment 1) and sometimes is sufficient (Experiment 2) to induce newborns' perception of illusory contours.

The kinetics of abiotic oxidation in the dark and the kinetics of biological mineralization in soil and in a compost environment of thermally oxidized LDPE were studied. It was demonstrated that different activation energies are obtained... more

The kinetics of abiotic oxidation in the dark and the kinetics of biological mineralization in soil and in a compost environment of thermally oxidized LDPE were studied. It was demonstrated that different activation energies are obtained for the thermal oxidation, depending on the composition of the materials. Significantly higher levels of biodegradability have been obtained in a soil environment at 23 C compared with the compost environment at 58 C. After two years of mineralization, 91% conversion to carbon dioxide was obtained in the soil test, compared with 43% in the compost test. The differences between fungal, archaeal and bacterial community structures in soil and compost after 607 days of biodegradability assay were mapped out. It was found that the most dominant bacterial and fungal terminal restriction fragments (TRFs) in the compost containing the test material are significantly different from the TRFs in the other environments.

Rotational immobilization of proteins permits characterization of the internal peptide and water molecule dynamics by magnetic relaxation dispersion spectroscopy. Using different experimental approaches, we have extended measurements of... more

Rotational immobilization of proteins permits characterization of the internal peptide and water molecule dynamics by magnetic relaxation dispersion spectroscopy. Using different experimental approaches, we have extended measurements of the magnetic field dependence of the proton-spin-lattice-relaxation rate by one decade from 0.01 to 300 MHz for 1 H and showed that the underlying dynamics driving the protein 1 H spin-lattice relaxation is preserved over 4.5 decades in frequency. This extension is critical to understanding the role of 1 H 2 O in the total proton-spin-relaxation process. The fact that the proteinproton-relaxation-dispersion profile is a power law in frequency with constant coefficient and exponent over nearly 5 decades indicates that the characteristics of the native protein structural fluctuations that cause proton nuclear spin-lattice relaxation are remarkably constant over this wide frequency and length-scale interval. Comparison of protein-proton-spin-lattice-relaxation rate constants in protein gels equilibrated with 2 H 2 O rather than 1 H 2 O shows that water protons make an important contribution to the total spin-lattice relaxation in the middle of this frequency range for hydrated proteins because of water molecule dynamics in the time range of tens of ns. This water contribution is with the motion of relatively rare, long-lived, and perhaps buried water molecules constrained by the confinement. The presence of water molecule reorientational dynamics in the tens of ns range that are sufficient to affect the spin-lattice relaxation driven by 1 H dipole-dipole fluctuations should make the local dielectric properties in the protein frequency dependent in a regime relevant to catalytically important kinetic barriers to conformational rearrangements.

The effect of 5-aminoimidazole-4-carboxamide-ribonucleoside (AICAR) activation of the AMP-activated protein kinase (AMPK) on the transport of the model radiolabeled dipeptide [3H]-D-Phe-L-Gln was investigated in the human epithelial colon... more

The effect of 5-aminoimidazole-4-carboxamide-ribonucleoside (AICAR) activation of the AMP-activated protein kinase (AMPK) on the transport of the model radiolabeled dipeptide [3H]-D-Phe-L-Gln was investigated in the human epithelial colon cancer cell line Caco-2. Uptake and transepithelial fluxes of [3H]-D-Phe-L-Gln were carried out in differentiated Caco-2 cell monolayers, and hPepT1 and glucose transporter 2 (GLUT2) protein levels were quantified by immunogold electron microscopy. AICAR treatment of Caco-2 cells significantly inhibited apical [3H]-D-Phe-L-Gln uptake, matched by a decrease in brush-border membrane hPepT1 protein but with a concomitant increase in the facilitated glucose transporter GLUT2. A restructuring of the apical brush-border membrane was seen by electron microscopy. The hPepT1-mediated transepithelial (A-to-B) peptide flux across the Caco-2 monolayers showed no significant alteration in AICAR-treated cells. The electrical resistance in the AICAR-treated monol...

During the resorbable-polymer-boom of the 1970s and 1980s, polycaprolactone (PCL) was used in the biomaterials field and a number of drug-delivery devices. Its popularity was soon superseded by faster resorbable polymers which had fewer... more

During the resorbable-polymer-boom of the 1970s and 1980s, polycaprolactone (PCL) was used in the biomaterials field and a number of drug-delivery devices. Its popularity was soon superseded by faster resorbable polymers which had fewer perceived disadvantages associated with long term degradation (up to 3-4 years) and intracellular resorption pathways; consequently, PCL was almost forgotten for most of two decades.

5-Hydroxymethylfurfural (HMF) is the most important intermediate product of the acid-catalyzed dehydration reaction of hexoses and/or Maillard reaction; furthermore, it is the most used index to evaluate thermal damages or ageing in food... more

5-Hydroxymethylfurfural (HMF) is the most important intermediate product of the acid-catalyzed dehydration reaction of hexoses and/or Maillard reaction; furthermore, it is the most used index to evaluate thermal damages or ageing in food products. Usually its degradation reactions, being very slow, are neglected. This study reports the findings concerning the degradation kinetics of HMF, in honeys of different floral origin at a temperature between 25 and 50 • C. The results highlighted higher degradation rates (k HMF degradation ) compared to the corresponding formation rates (k HMF formation ) in chestnut and citrus samples. Similar k-values were found in multifloral honey. Moreover, the reaction of HMF degradation was characterized by lower activation energy (E a ) values compared to E a formation values. The final concentration of HMF in honey, during storage at room temperature, should be ascribed to high sugar concentration. The fluctuation of HMF in honeys could depend on the equilibrium between the accumulation and the degradation processes. This can affect the validity of HMF as storage index in some honeys, above all during the analysis of those honeys whose legislation is too restrictive (citrus) or in chestnut honey analysis where it does not accumulate.

The current state of knowledge of cement hydration mechanisms is reviewed, including the origin of the period of slow reaction in alite and cement, the nature of the acceleration period, the role of calcium sulfate in modifying the... more

The current state of knowledge of cement hydration mechanisms is reviewed, including the origin of the period of slow reaction in alite and cement, the nature of the acceleration period, the role of calcium sulfate in modifying the reaction rate of tricalcium aluminate, the interactions of silicates and aluminates, and the kinetics of the deceleration period. In addition, several remaining controversies or gaps in understanding are identified, such as the nature and influence on kinetics of an early surface hydrate, the mechanistic origin of the beginning of the acceleration period, the manner in which microscopic growth processes lead to the characteristic morphologies of hydration products at larger length scales, and the role played by diffusion in the deceleration period. The review concludes with some perspectives on research needs for the future.

Ubiquinone-10 (CoQ10), a vitamin-like lipophilic component of the membrane-bound electron transport system, has a wide range of therapeutic, neutraceutical, and cosmeceutical applications. The objective of this study was to optimize... more

Ubiquinone-10 (CoQ10), a vitamin-like lipophilic component of the membrane-bound electron transport system, has a wide range of therapeutic, neutraceutical, and cosmeceutical applications. The objective of this study was to optimize nutritional requirements for production of CoQ10 by Paracoccus dinitrificans NRRL B-3785 fermentation. Effect of type and concentration of carbon and nitrogen source on fermentation kinetic parameters were analyzed using logistic and Luedeking-Piret equations. In submerged batch fermentation, yield of CoQ10 was 12.22 mg/L when 40 g/L glycerol was used and specific growth rate (0.056/h) as well as growth associated constant (α=0.680 mg/g) were higher as compared to other concentrations. Ammonium nitrate and proteose peptone at 5 (α=0.677 mg/g; β= 0.0072 mg/g·h) and 20 g/L (α=0.806 mg/g; β=0.0074 mg/g·h), respectively, were optimal for CoQ10 production. CoQ10 formation observed to be both growth and nongrowth associated. In optimized medium CoQ10 formation increased considerably from 1.91 to 14.12 mg/L.

Radical polymerization of limonene (limonene) using benzoyl peroxide (BPO) as an initiator at 85 C 6 1 C under an inert atmosphere of nitrogen in xylene as solvent was carried out. The system follows nonideal kinetics: R p a [I] 0.3 [M]... more

Radical polymerization of limonene (limonene) using benzoyl peroxide (BPO) as an initiator at 85 C 6 1 C under an inert atmosphere of nitrogen in xylene as solvent was carried out. The system follows nonideal kinetics: R p a [I] 0.3 [M] 1.4 , due to both primary radical termination and degradative chain transfer reaction. The activation energy of the polymerization was estimated to be 22.97 kJ mol À1 . 1 H-NMR spectrum of polymer shows the presence of a triplet between 2 and 2.5 d, which reveals that b-carbon of limonene is the active site in the polymerization of limonene. The FTIR spectrum of the polymer shows band at 1645 cm À1 due to gem disubstituted C¼ ¼C stretching vibrations. The glass transition temperature (T g ) of the polylimonene of the polylimonene is 116 C.

Efficient tetrahydrocannabinol (D 9 -THC) production from cannabis is important for its medical application and as basis for the development of production routes of other drugs from plants. This work presents one of the steps of D 9 -THC... more

Efficient tetrahydrocannabinol (D 9 -THC) production from cannabis is important for its medical application and as basis for the development of production routes of other drugs from plants. This work presents one of the steps of D 9 -THC production from cannabis plant material, the decarboxylation reaction, transforming the D 9 -THC-acid naturally present in the plant into the psychoactive D 9 -THC. Results of experiments showed pseudo-first order reaction kinetics, with an activation barrier of 85 kJ mol À1 and a pre-exponential factor of 3.7 Â 10 8 s À1 .

Zinc oxide nanoparticles (nZnO) are one of the most highly produced nanomaterials and are used in numerous applications including cosmetics and sunscreens despite reports demonstrating their cytotoxicity. Dissolution is viewed as one of... more

Zinc oxide nanoparticles (nZnO) are one of the most highly produced nanomaterials and are used in numerous applications including cosmetics and sunscreens despite reports demonstrating their cytotoxicity. Dissolution is viewed as one of the main sources of nanoparticle (NP) toxicity, however dissolution studies can be time-intensive to perform and complicated by issues such as particle separation from solution. Our work attempts to overcome some of these challenges by utilizing new methods using UV/vis and fluorescence spectroscopy to quantitatively assess nZnO dissolution in various biologically relevant solutions. All biological buffers tested induce rapid dissolution of nZnO. These buffers, including HEPES, MOPS, and PIPES, are commonly used in cell culture media, cellular imaging solutions and to maintain physiological pH. Additional studies using X-ray diffraction, FT-IR, X-ray photoelectron spectroscopy, ICP-MS and TEM were performed to understand how the inclusion of these non-essential media components impacts the behavior of nZnO in RPMI media. From these assessments, we demonstrate that HEPES causes increased dissolution kinetics, boosts the conversion of nZnO into zinc phosphate/carbonate and, interestingly, alters the structural morphology of the complex precipitates formed with nZnO in cell culture conditions. Cell viability experiments demonstrated that the inclusion of these buffers significantly decreases the viability of Jurkat leukemic cells when challenged with nZnO. This work demonstrates that biologically relevant buffering systems dramatically impact the dynamics of nZnO including dissolution kinetics, morphology, complex precipitate formation, and toxicity profiles.

Four sets of thin-section scale, Mode I (open mode), cemented microfractures are present in sandstone from the Eocene Misoa Formation, Maracaibo basin, Venezuela. The first set of microfractures is intragranular (F1), formed early during... more

Four sets of thin-section scale, Mode I (open mode), cemented microfractures are present in sandstone from the Eocene Misoa Formation, Maracaibo basin, Venezuela. The first set of microfractures is intragranular (F1), formed early during compaction and are filled with quartz cement precipitated at temperatures equal to or higher than 100 8C. The second set of microfractures (F2) is cemented by bituminite-pyrite, formed at temperatures between 60 and 100 8C, and are associated with kerogen maturation and hydrocarbon migration from underlying overpressured source rocks. The third set of microfractures (F3) is fully cemented by either quartz cement or calcite cement. The former has fluid inclusion homogenization temperatures between 149 and 175 8C. These temperatures are mostly higher than maximum burial temperatures (~160 8C), suggesting that upward flow, caused by a pressure gradient, transported silica vertically which crystallized into the fractures. Upward decompression may have also caused a P CO 2 drop, which, at constant temperature, allowed simultaneous carbonate precipitation into the third microfracture set. The fourth set of thin-section scale microfractures (F4) is open or partially cemented by sideritehematite and other iron oxides. The presence of hematite and iron oxides in microfractures is evidence for oxidizing conditions that may be associated with the uplift of the Misoa formation. In order to time and place constraints on the depth of formation of the fourth set of microfractures, we have coupled published quartz cementation kinetic algorithms with uniaxial strain equations and determined if, in fact, they could be associated with the uplift of the formation. Our results suggest that thermoelastic contraction, caused by the formation's uplift, erosion, and consequent cooling is a feasible mechanism for the origin of the last fracture set. Hence, we infer that meteoric water invasion into the fractures, at the end of the uplift, cause the precipitation of oxides and the transformation of siderite to hematite. D

activity was measured in rats treated with daily injections of ethanol (0.1 g/kg body wt) and or dexamethasone (1 mg/kg body wt) for 5 consecutive days. Ethanol produced a biphasic reduction of choline acetyltransferase activity in rat... more

activity was measured in rats treated with daily injections of ethanol (0.1 g/kg body wt) and or dexamethasone (1 mg/kg body wt) for 5 consecutive days. Ethanol produced a biphasic reduction of choline acetyltransferase activity in rat cerebral cortex, which at most time points was further decreased by simultaneous injection of dexamethasone. Kinetic studies of cortex choline acetyltransferase activity in rats that had received 5 daily injections of ethanol or ethanol and dexamethasone indicated that the observed reduction in enzyme activity was due to an apparent reduction in affinity (K,,) of the enzyme for acetyl coenzyme A with no significant change in the total amount of enzyme present (V,,,,). This finding has implications with respect to the use of choline acetyltransferase as a marker for cholinergic neurons, and for the understanding of the regulation of choline acetyltransferase activity in the brain.

Plant-based fibers have been selected as suitable reinforcements for composites due to their good mechanical performances and environmental advantages. This paper describes the development of a simulation procedure to predict the... more

Plant-based fibers have been selected as suitable reinforcements for composites due to their good mechanical performances and environmental advantages. This paper describes the development of a simulation procedure to predict the temperature profile and the curing behavior of the hemp fiber/thermoset composite during the molding process. The governing equations for the non-linear transient heat transfer and the resin cure kinetics were presented. A general purpose multiphysics finite element package was employed. The procedure was applied to simulate one-dimensional and three-dimensional models. Experiments were carried out to verify the simulated results. Experimental data shows that the simulation procedure is numerically valid and stable, and it can provide reasonably accurate predictions. The numerical simulation was performed for a three-dimensional complex geometry of an automotive part to predict the temperature distribution and the curing behavior of the composite during the molding process.

The processing of hard and liquid silicone rubbers (LSR) are compared by means of modeling and simulation. The curing process for both, hard and liquid silicone, are modeled using the auto-catalytic Kamal-Sourour model and a nonlinear... more

The processing of hard and liquid silicone rubbers (LSR) are compared by means of modeling and simulation. The curing process for both, hard and liquid silicone, are modeled using the auto-catalytic Kamal-Sourour model and a nonlinear regression method is used to find the kinetic parameters. The fitted kinetic model is then combined with the heat balance equations to simulate real processing conditions. Both resins are compared in terms of process perform-ance and consistency of the final part. The results show that even though hard silicone rubbers are less expensive resins, its processing conditions present several issues of consistency and quality control when compared with LSR.

Localization of the interface between the candidate antibody and its antigen target, commonly known as epitope mapping, is a critical component of the development of therapeutic monoclonal antibodies. With the recent availability of... more

Localization of the interface between the candidate antibody and its antigen target, commonly known as epitope mapping, is a critical component of the development of therapeutic monoclonal antibodies. With the recent availability of commercial automated systems, hydrogen / deuterium eXchange (HDX) is rapidly becoming the tool for mapping epitopes preferred by researchers in both industry and academia. However, this approach has a significant drawback in that it can be confounded by 'allosteric' structural and dynamic changes that result from the interaction, but occur far from the point(s) of contact. Here, we introduce a 'kinetic' millisecond HDX workflow that suppresses allosteric effects in epitope mapping experiments. The approach employs a previously introduced microfluidic apparatus that enables millisecond HDX labeling times with on-chip pepsin digestion and electrospray ionization. The 'kinetic' workflow also differs from conventional HDX-based epitope mapping in that the antibody is introduced to the antigen at the onset of HDX labeling. Using myoglobin / anti-myoglobin as a model system, we demonstrate that at short 'kinetic' workflow labeling times (i.e., 200 ms), the HDX signal is already fully developed at the 'true' epitope, but is still largely below the significance threshold at allosteric sites. Identification of the 'true' epitope is supported by computational docking predictions and allostery modeling using the rigidity transmission allostery algorithm.

The purpose of this study was to examine the effects of reduced muscle temperature (T m) on gas exchange kinetics and haemodynamics at the start of exercise. Six male subjects performed moderate cycle exercise under reduced (C) and normal... more

The purpose of this study was to examine the effects of reduced muscle temperature (T m) on gas exchange kinetics and haemodynamics at the start of exercise. Six male subjects performed moderate cycle exercise under reduced (C) and normal (N) T m conditions. T m and rectal temperature were signi®cantly reduced by immersion in cold water (by 6.6°C and 1.8°C, respectively). The increases in oxygen uptake (VO 2) and oxygen pulse (VO 2 /HR) during phase 1 (abrupt increase after the start of exercise) were signi®cantly lower under C than under N. The time constant for O 2 under C (36.0 7.7 (SD) s) was signi®cantly greater than under N (27.5 4.4 s); however, the time constants of cardiac output under C (38.3 16.6 s) and N (33.7 18.5 s) were similar. These results suggest that the slower VO 2 on-response under reduced T m conditions is caused by decreased O 2 extraction in working muscle and/or by impairment of oxidative reactions by reduced muscle temperature.

The effects of various physical properties (particle size, shape, surface area, crystal structure, and phase composition) on the photocatalytic performance of nanosized TiO 2 were studied through the photodegradation of Congo Red. Kinetic... more

The effects of various physical properties (particle size, shape, surface area, crystal structure, and phase composition) on the photocatalytic performance of nanosized TiO 2 were studied through the photodegradation of Congo Red. Kinetic results showed that anatase TiO 2 was a superior photocatalyst to rutile TiO 2 due to the inherent difference in the two crystal structures. Anatase TiO 2 nanorods with predominantly (1 0 1) surface exhibited low activity because the non-dissociative adsorption of H 2 O to this surface retarded the generation of OH • radicals required for facile photocatalytic oxidation. It was found for the first time that the shape of TiO 2 nanocrystals significantly affected their photocatalytic activities. The previously reported anatase-rutile synergetic effect in commercialized mixed-phase TiO 2 (Degussa P25) was not observed in this study, perhaps, due to poor contact between the two phases and the extremely small sizes, as well as the not-optimized phase compositions in the current work.

The rate and kinetics of the thermal decomposition of potassium iodate (KIO 3) has been studied as a function of particle size, in the range 63-150 lm, by isothermal thermogravimetry at different temperatures, 790, 795, 800 and 805 K in... more

The rate and kinetics of the thermal decomposition of potassium iodate (KIO 3) has been studied as a function of particle size, in the range 63-150 lm, by isothermal thermogravimetry at different temperatures, 790, 795, 800 and 805 K in nitrogen atmosphere. The theoretical and experimental mass loss data are in good agreement for the thermal decomposition of all samples of KIO 3 at all temperatures studied. The isothermal decomposition of all samples of KIO 3 was subjected to both model-fitting and model-free (isoconversional) kinetic methods of analysis. It has been observed that the activation energy values are independent of the particle size. Isothermal model-fitting analysis shows that the thermal decomposition kinetics of all the samples of KIO 3 studied can be best described by the contracting cube equation.

Human papilloma virus infection is increasing at an alarming rate. The ability of the virus to establish a subclinical infection and its association with malignancy of the lower genital tract make the statistics even more worrisome.... more

Human papilloma virus infection is increasing at an alarming rate. The ability of the virus to establish a subclinical infection and its association with malignancy of the lower genital tract make the statistics even more worrisome. Topical application of acetic acid solution provokes temporal alterations of the light-scattering properties of human papilloma virus-induced lesions of anogenital area. For the in vivo study of the phenomenon, an imaging system has been employed, which performs time-lapse imaging and enables the calculation and display of the kinetics of the provoked alterations in any point within the examined area. Confirmation of diagnosis has been established with conventional histology and polymerase chain reaction. It has been shown that the method provides early detection and staging of skin alteration or transformation due to human papilloma virus infection and enables mapping of the infected area.

Leaching of fluoride, a toxic element, from industrial wastes and fluoride minerals like fluorspar (CaF 2 ) into ground water may cause significant contamination, which may require major treatment before use as drinking water. The present... more

Leaching of fluoride, a toxic element, from industrial wastes and fluoride minerals like fluorspar (CaF 2 ) into ground water may cause significant contamination, which may require major treatment before use as drinking water. The present study described the removal of F-on bone char in batch studies as a function of co-existing mineral ions phosphate, carbonate, sulphate, chloride, sodium, magnesium, etc. present in drinking water (surface and groundwater), at constant temperature conditions and without pH adjustments. Fourier transform infrared spectra of bone char before and after adsorption demonstrated that ca-PO 4 3-and ca-OH functional groups played an important role for F -removal, and the mechanism was complex where both ionexchange and electrostatic ion-binding between the active positive sites of calcium in the bone char and fluoride ions. This led to an increase in pH of the water during the sorption of fluoride. The results suggest that bone char can be used effectively the removal of F -ions from groundwater utilized as drinking water.

We studied the activity of 14 compounds, all of which have been shown to interfere in plant cell division, in two animal tumor cell cultures, EL-4 and L1210. Four compounds [propham, chlorpropham, bensulide... more

We studied the activity of 14 compounds, all of which have been shown to interfere in plant cell division, in two animal tumor cell cultures, EL-4 and L1210. Four compounds [propham, chlorpropham, bensulide S-(O,O-diisopropylphosphorodithioate) ester of A/-(2-mercaptoethyl)benzenesulfonamide), and siduron] had a 50% inhibitory dose less than 10~4 M; six [2,3,5-triiodobenzoic acid, (2,4-dichlorophenoxy)acetic acid, bromacil, (2,4,5-trichlorophenoxy)acetic acid, naptalam, and (4-chloro-2-methylphenoxy)acetic acid] had a 50% inhibitory dose between 10~" and 10~3 M, and the remaining four 2,3: 4,6-di-O-isopropylidene-2-keto-L-gulonate, eptam, maleic hydrazide, and 4-(methylsulfonyl)-2,6-dinitro-/\/,N,-dipropylaniline] had a 50% inhibitory dose at higher than 10~3 M. There was a significant correlation between the effect on the two cell lines as well as between the inhibition of cell proliferation and that of thymidine and leucine uptake. More detailed study of cell proliferation and leucine and thymidine uptake for bensu lide and 2,3,5-triiodobenzoic acid revealed a dose-response pattern of inhibition starting shortly after exposure of the cells to the compounds. These results indicate that some inhibitors of plant cell division are capable of inhibiting the proliferation of animal tumor cells.

The crosslinking of the unsaturated polyester was studied by using experiments and a model of the process. The kinetic parameters were calculated from the heat flux-time curves obtained by differential scanning calorimetry (DSC,... more

The crosslinking of the unsaturated polyester was studied by using experiments and a model of the process. The kinetic parameters were calculated from the heat flux-time curves obtained by differential scanning calorimetry (DSC, Netzsch-Simultaneous Thermal Analyser DSC 200), working in DSC (dynamic) mode. The temperature-time histories were studied in plain sheet copper mould. The mathematical model was constructed by taking into account the heat transferred by conduction through the resin, as well as the kinetics of heat generated by the crosslinking reaction. The contributions to the rise in temperature from heat conduction and chemical reaction are different in different parts of the composite, and can explain the temperature-, or degree of crosslinking (DOC)time histories. By considering temperature-time histories developed within the sample, more extensive knowledge of the process can be obtained. The effect of the heat transfer by conduction through the composite as well as the internal heat generated by the cure reaction is clearly shown, despite the complexity of the process. Finally, good agreement between experimental data and predicted mathematical model of the crosslinking process in plane sheet mould was shown.

The active ingredient of marijuana is(−)-Δ 9 -tetrahydrocannabinol(Δ 9 -THC).Δ 9 -THC and other natural and synthetic cannabinoids such as CP-55, 940 inhibit spontaneous activity and produce catalepsy in animals in a receptor-mediated... more

The active ingredient of marijuana is(−)-Δ 9 -tetrahydrocannabinol(Δ 9 -THC).Δ 9 -THC and other natural and synthetic cannabinoids such as CP-55, 940 inhibit spontaneous activity and produce catalepsy in animals in a receptor-mediated fashion. Tolerance develops to the motor ...

The kinetics of oxygen reduction was investigated in acid solutions on Pt monolayers deposited on modified carbon-supported PdIr nanoparticles using the rotating diskelectrode technique. Iridium is introduced into the Pd substrate in... more

The kinetics of oxygen reduction was investigated in acid solutions on Pt monolayers deposited on modified carbon-supported PdIr nanoparticles using the rotating diskelectrode technique. Iridium is introduced into the Pd substrate in order to fine-tune the Pt-Pd interactions and to improve Pd stability under operating conditions of the fuel cell. The kinetics of the oxygen reduction reaction shows enhancement with the Pt monolayer on the PdIr nanoparticle surfaces in comparison with the reaction on Pt/

Five subjects who participated in an earlier study (Lelo et al., 1986b) of the comparative pharmacokinetics of caffeine (CA) and its primary monodemethylated metabolites paraxanthine (PX), theobromine (TB) and theophylline (TP) were... more

Five subjects who participated in an earlier study (Lelo et al., 1986b) of the comparative pharmacokinetics of caffeine (CA) and its primary monodemethylated metabolites paraxanthine (PX), theobromine (TB) and theophylline (TP) were administered CA to steady-state. Using areas under the plasma concentration-time curves for each of the dimethylxanthines derived from CA in the steady-state study and individual plasma clearances of PX, TB and TP determined in the previous study, the fractional conversion of CA to PX, TB and TP and the individual partial clearances of CA have been defined. The mean (± s.d.) fractional conversion of CA to PX, TB and TP was 79.6 + 21.0%, 10.8 + 2.4% and 3.7 + 1.3%, respectively. When only demethylation pathways are considered PX, TB and TP accounted for 83.9 + 5.4%, 12.1 + 4.1% and 4.0 + 1.4%, respectively of the CA demethylations. The mean partial clearance of CA to PX was approximately 8-fold and 23-fold greater than those to TB and TP respectively. These data confirm earlier reports that PX is the major metabolite of CA in humans but suggest that PX formation is quantitatively more important than previously believed.

A kinetic-potentiometric method is described for the quantitative assay of formaldehyde (HCHO) in pharmaceutical and industrial preparations. It is based on the reaction of HCHO with (ethylenediamine)-Cu(II)sulfate [Cu(CH 2 NH 2) 2 (H 2... more

A kinetic-potentiometric method is described for the quantitative assay of formaldehyde (HCHO) in pharmaceutical and industrial preparations. It is based on the reaction of HCHO with (ethylenediamine)-Cu(II)sulfate [Cu(CH 2 NH 2) 2 (H 2 O) 2 ] Á SO 4. The changes in potential, resulting from the release of the Cu(II) cations, are monitored with a Cu(II)-ion selective electrode. The calibration curve for the HCHO is linear in the concentration range 50-250 mg L À1 , with a limit of detection of 8.5 mg L À1. The method shows very good reproducibility with an RSD of 2.6% for successive injections (n ¼ 5) of 150 mg L À1 HCHO primary solution, while it is interference free. The method was successfully tested in various industrial and pharmaceutical preparations.

In this work, two toxic compound, sulfide and thiocyanate were determined simultaneously using kinetic spectrophotometry. These anions have shown the catalytic effects on the reaction between iodine and azide. Since the system was... more

In this work, two toxic compound, sulfide and thiocyanate were determined simultaneously using kinetic spectrophotometry. These anions have shown the catalytic effects on the reaction between iodine and azide. Since the system was nonlinear, a nonlinear model, principal componentwavelet neural network (PC-WNN) was used as the multivariate calibration method. The principal component analysis was used to decrease the dimension of the original matrix. In other words, the scores of the PCs, 5, instead of the original variables, 301, were used as the input for the model. Two methods were used to select the most relevant principal components: eigenvalue ranking and correlation ranking. In this work, eigenvalue and correlation ranking methods have shown better results for thiocyanate and sulfide, respectively, and it can be concluded that these methods are complementary. The WNN has several advantages relative to other types of neural network such as better convergence ability. The data set was divided to calibration, prediction and validation sets. Each set was selected so that the concentrations of the analytes were approximately covered the entire ranges of the analytes. Mean relative error for thiocyanate and sulfide in validation set were 8.5 and 10.6, respectively. Thiocyanate and sulfide can be determined in the range of 60-700 ng ml −1 and 20-400 ng ml −1 , respectively. The proposed method was applied for the determination of sulfide and thiocyanate in real samples such as tap, waste and river waters with satisfactory results.

The aim of this work was to formulate sodium alginate nanospheres of amphotericin B by controlled gellification method and to evaluate the role of the nanospheres as a "passive carrier" in targeted antifungal therapy. Methods: Sodium... more

The aim of this work was to formulate sodium alginate nanospheres of amphotericin B by controlled gellification method and to evaluate the role of the nanospheres as a "passive carrier" in targeted antifungal therapy. Methods: Sodium alginate nanospheres of amphotericin B were prepared by controlled gellification method, and the particle size analysis was carried out by scanning electron microscopy. The carrier capacity of sodium alginate was evaluated in terms of drug to polymer ratio. In vitro release study was carried out on all drug loaded nanospheres by the dialysis method. Release kinetics of drug from different drug loaded nanospheres was also determined. The in vivo antifungal efficacy of nanospheres bound drug vis-à-vis the free drug was evaluated in candidiasis-induced mice models. Results: Preparation of nanospheres through controlled gellification method yielded particles with a size range of 419.6 ± 0.28 nm. Studies on drug to polymer ratio showed a linear relationship between concentration of drug and drug loading capacity. In vitro release kinetic study revealed that the release of drug from the nanospheres followed Fickian diffusion. In vivo studies showed that the nanospherebound drug produced a higher antifungal efficacy than the free drug. Conclusion: The formulated sodium alginate nanospheres containing amphotericin B was found to have better antifungal activity when compared to the free drug and also yielded sustained in vitro release.

We have analyzed cell cycle parameters for the Aedes albopictus C7-10 mosquito cell line, which has been systematically developed for somatic cell genetics, expression of transfected genes, and synthesis of hormone-inducible proteins. In... more

We have analyzed cell cycle parameters for the Aedes albopictus C7-10 mosquito cell line, which has been systematically developed for somatic cell genetics, expression of transfected genes, and synthesis of hormone-inducible proteins. In rapidly cycling cells, we measured a generation time of 10-12 h. The duration of mitosis (M) was < or = 1 h, and the DNA synthesis phase (S) required 6 h. Unlike Drosophila melanogaster Kc cells, in which the G2 gap is substantially longer than G1, in C7-10 cells G1 and G2 each lasted approximately 2 h. In these cells, the duration of both S and G2 was independent of the population doubling time, and the increase in population doubling time as cells approached confluency was due to prolongation of G1. When treated with the insect steroid hormone, 20-hydroxyecdysone, C7-10 mosquito cells complete the cycle in progress before undergoing a reversible arrest.

The simulation of nuclear power plant accident conditions requires three-dimensional (3D) modeling of the reactor core to ensure a realistic description of physical phenomena. The operational flexibility of Light Water Reactor (LWR)... more

The simulation of nuclear power plant accident conditions requires three-dimensional (3D) modeling of the reactor core to ensure a realistic description of physical phenomena. The operational flexibility of Light Water Reactor (LWR) plants can be improved by utilizing accurate 3D coupled neutronics/thermal-hydraulics calculations for safety margins evaluations. There are certain requirements to the coupling of thermal-hydraulic system codes and neutron-kinetics codes that ought to be considered. The objective of these requirements is to provide accurate solutions in a reasonable amount of CPU time in coupled simulations of detailed operational transient and accident scenarios. These requirements are met by the development and implementation of six basic components of the coupling methodologies: ways of coupling (internal or external coupling); coupling approach (integration algorithm or parallel processing); spatial mesh overlays; coupled time-step algorithms; coupling numerics (explicit, semi-implicit and implicit schemes); and coupled convergence schemes. These principles of the coupled simulations are discussed in details along with the scientific issues associated with the development of appropriate neutron cross-section libraries for coupled code transient modeling. The current trends in LWR nuclear power generation and regulation as well as the design of next generation LWR reactor concepts along with the continuing computer technology progress stimulate further development of these coupled code systems. These efforts have been focused towards extending the analysis capabilities as well as refining the scale and level of detail of the coupling. This article analyses the coupled phenomena and modeling challenges on both global (assembly-wise) and local (pin-wise) levels. The issues related to the consistent qualification of coupled code systems as well as their application to different types of LWR transients are presented. Finally, the advances in numerical and computation techniques for coupled code simulations are summarized with outlining remaining challenges.

With declining petroleum reserves, increased world demand, and unstable politics in some of the worlds richest oil producing regions, the capability for the U.S. to produce synthetic liquid fuels from domestic resources is critical to... more

With declining petroleum reserves, increased world demand, and unstable politics in some of the worlds richest oil producing regions, the capability for the U.S. to produce synthetic liquid fuels from domestic resources is critical to national security and economic stability. Coal, biomass and other carbonaceous materials can be converted to liquid fuels using several conversion processes. The leading candidate for

As an approach to the study of mammalian gene expression, the promoters and translation initiation regions of the rat preproinsulin II and the simian virus 40 early genes were fused to the structural gene of Escherichia coli... more

As an approach to the study of mammalian gene expression, the promoters and translation initiation regions of the rat preproinsulin II and the simian virus 40 early genes were fused to the structural gene of Escherichia coli 3-galactosidase, a sensitive probe for gene expression. These fusions were introduced into COS-7 cells, a simian virus 40 large tumor-antigen-producing monkey kidney cell line, where they directed the synthesis of enzymatically active hybrid 3-galactosidase proteins. Conditions for transfection were varied to optimize the expression of 13-galactosidase activity in the transfected cells. The pH optimum of this activity was found to be 7.0, the same as that of native E. coli fgalactosidase and distinct from the major lysosomal "acid" fl-galactosidase. The fused preproinsulin-fl-galactosidase was further characterized by gel electrophoresis of nondenatured cell extracts stained by a fluorogenic substrate and by immunoprecipitation and gel electrophoresis of 3H-labeled cell proteins. These results all indicate that fully active tetrameric P-galactosidase hybrids can be produced in mammalian cells. The expression of preproinsulin-,B-galactosidase activity was measured in the presence of high glucose, insulin, dexamethasone, or epidermal growth factor but no regulatory changes were observed. Gene fusions utilizing the Escherichia coli lacZ structural gene provide an especially suitable method for studying gene expression and regulation (1). Its product, f3-galactosidase, can be as

The pharmacodynamics and pharmacokinetics of bupivacaine in solution and in liposome preparations following subcutaneous administration were studied in rats. Multilamellar vesicles entrapping bupivacaine solution were prepared. The local... more

The pharmacodynamics and pharmacokinetics of bupivacaine in solution and in liposome preparations following subcutaneous administration were studied in rats. Multilamellar vesicles entrapping bupivacaine solution were prepared. The local anaesthetic effect was estimated by the tail-flick test in Wistar rats treated with 1 mg bupivacaine in 0.2-ml. preparations. Plasma concentrations of bupivacaine were determined by high-performance liquid chromatography. The results showed that both bupivacaine solution and bupivacaine liposomes revealed local anaesthetic effects in the initial tail-flick test (15 min after injection). With bupivacaine liposomes, the duration of action was 5-fold (447 ± 28.9 vs 87 ± 6.7 min), the maximum possible effect was 2-fold (100 ± 0 vs 47.6 ± 13%), and the peak plasma concentration (Cmax) was less than one-fifth (0.12 ± 0.04 vs 0.65 ± 0.04 μg mL−1) that with bupivacaine solution. The sensory block effect of bupivacaine solution completely resolved at 90 min,...

Hybridization probes produced from DNA sequences have proven to be a powerful tool in the rapid and sensitive analysis of natural microbial communities. By using function-specific probes, such as those identifying genes coding for... more

Hybridization probes produced from DNA sequences have proven to be a powerful tool in the rapid and sensitive analysis of natural microbial communities. By using function-specific probes, such as those identifying genes coding for photosynthesis, the potential a microbial community has for performing a given function may be rapidly determined. Gene probes have also been used in the idelatification and isolation of a specific catabolic genotype in less than one-fourth the time required for the conventional culture enrichment technique. Species-specific probes constructed from portions of genes coding for ribosomal RNA have been used for the rapid identification and enumeration of bacterial species in environmental samples. The use of reassociation kinetics as a measure of community diversity and complexity is also discussed. The successful application of this technique to community analysis may reduce the time required from 1 year, for conventional analysis, to 2 weeks.

The stress-induced flow of non-Newtonian glass-forming systems is analysed in order to obtain a general algorithm for describing the kinetics of relaxation and retardation in glass-forming melts. It is shown that the existing empirical... more

The stress-induced flow of non-Newtonian glass-forming systems is analysed in order to obtain a general algorithm for describing the kinetics of relaxation and retardation in glass-forming melts. It is shown that the existing empirical relations for plastic, pseudoplastic and dilatant flow can be derived in the framework of the PrandtI-Eyring potential barrier model, which is extended in order to includedilatant effects. The advantages and shortcomings of this molecular model are considered using experimental evidence on the flow of organic polymers, inorganic glasses and metal alloy glass-formers. It is shown that the mathematical formalism following from the potential barrier model can be conveniently used in order to derive the non-linear kinetics of relaxation of simple and polymer glass-forming melts.

The native b-D-glucan exohydrolase isoenzyme ExoI from barley seedlings, designated HvExoI, was the first GH3 glycoside hydrolase, for which a crystal structure was determined. A precise understanding of relationships between structure... more

The native b-D-glucan exohydrolase isoenzyme ExoI from barley seedlings, designated HvExoI, was the first GH3 glycoside hydrolase, for which a crystal structure was determined. A precise understanding of relationships between structure and function in this enzyme has been gained by structural and enzymatic studies. To allow testing of hypotheses gained from these studies, an efficient system for expression of HvExoI in Pichia pastoris was developed using a codon-optimized cDNA. Protein expression at a temperature of 20°C yielded a recombinant enzyme, designated rHvExoI, which had molecular masses of 70-110 kDa due to heavy glycosylation at Asn221, Asn498 and Asn600, the three sites of N-glycosylation in native HvExoI. Most of the N-linked carbohydrate could be removed from rHvExoI, resulting in N-deglycosylated rHvExoI with a substantially decreased molecular mass of 67 kDa. rHvExoI was able to hydrolyse barley (1,3;1,4)-b-D-glucan, laminarin and lichenans. The catalytic efficiency value k cat /K M of rHvExoI with barley (1,3;1,4)-b-D-glucan was similar to that reported for native HvExoI. Further, laminaribiose, cellobiose and gentiobiose were formed through transglycosylation reactions with 4-nitrophenyl b-D-glucoside and barley (1,3;1,4)-b-D-glucan. Overall, the biochemical properties of rHvExoI were similar to those reported for native HvExoI, although differences were seen in thermostabilities and hydrolytic rates of certain blinked glucosides.

Sarcoplasmic reticulum (SR), Ca *+ + Mg *+-ATPase, and Ca *+-ioncphore were obtained from white rabbit skeletal muscles. Methylmercury inhibited the Ca *+ + Mg*+-ATPase an d Ca**-transport but had no effect on the Ca*+ionophore. Mercuric... more

Sarcoplasmic reticulum (SR), Ca *+ + Mg *+-ATPase, and Ca *+-ioncphore were obtained from white rabbit skeletal muscles. Methylmercury inhibited the Ca *+ + Mg*+-ATPase an d Ca**-transport but had no effect on the Ca*+ionophore. Mercuric chloride inhibited all three functions (i.e., ATPase, transport and ionophoric activity). The mechanism of HgC12 inhibition of the Ca*+ionophore was by competition with Ca*+ for Ca*'-ionophoric site whereas its inhibition of the enzyme ar,d Ca*+-transport was due to the blockage of essential sulfhydryl (-SH) groups. Ca*' + Mg*+-ATPase and Ca*+-transport were more sensitive to methylmercury than to HgC12. Acetylcholine receptor (AChR) was obtained for the electric organ of T.

The ALD behavior of Hf(EtCp)2Me2 with O3 as coreactant was investigated at high temperature (350-400°C), an ALD deposition rate of 0.72Å/cycle was achieved. Hf(EtCp)2Me2 showed the best compromise between thermal stability, physical... more

The ALD behavior of Hf(EtCp)2Me2 with O3 as coreactant was investigated at high temperature (350-400°C), an ALD deposition rate of 0.72Å/cycle was achieved. Hf(EtCp)2Me2 showed the best compromise between thermal stability, physical properties, and deposition behavior. Similar zirconocenes were als o studied: ZrCp2Me2, Zr(MeCp)2Me2, Zr(EtCp)2Me2 and Zr(EtCp)(NMe2)3.

Using a new strategy, capture-RT-PCR, bcrablfusion mRNA sequences were specifically and sensitively detected in samples of whole blood from leukemia patients with the Philadelphia chromosome. Sample processing required only mixing blood... more

Using a new strategy, capture-RT-PCR, bcrablfusion mRNA sequences were specifically and sensitively detected in samples of whole blood from leukemia patients with the Philadelphia chromosome. Sample processing required only mixing blood with the chaotropic salt, GuSCN, and mRNA was captured during a short incubation of prepared blood with an affinity membrane. Immobilized mRNA sequences were amplified without elution. No radioisotopes or Southern transfer were needed.