Search

type:Conference Paper, High quality drying of therapeutic protein-solution is important in medical and pharmaceutical processing. Freeze-drying is mostly used, but it takes a long drying-time and causes damages of protein structures. In order to improve the drying quality, we propose a microwave vacuum drying performed at ambient temperatures under low-pressure conditions. We are focusing on the Parma-Zyme method for the evaporative drying of protein solutions such as egg white or lysozyme with vitrification. Circular dichroism (CD) spectroscopy is used to detect protein conformation changes due to the drying, and it is found that the ambient temperature drying can preserve the protein conformation., 21st International Drying Symposium(IDS’2018), 11-14 September 2018, València, Spain

Aim: Short-chain fatty acids (SCFA) stimulate colonic contraction and secretion, which are mediated by an enteric reflex via a mucosal sensing and cholinergic mechanisms. The involvement of G-protein signal transduction was examined in the secretory response to luminal propionate sensing in rat distal colon. Methods: Mucosa-submucosa and mucosa preparations were used to measure short-circuit current (I_[sc]) and acetylcholine (ACh) release respectively. Cholesterol-rich membrane microdomains, lipid rafts/caveolae, were fractionated using a sucrose-gradient ultra-centrifugation after detergent-free extraction of the isolated colonic crypt. Results: Luminal addition of methyl-β-cyclodextrin (10 mM) and mastoparan (30 μM), lipid rafts/caveolae disruptors, significantly inhibited luminal propionate-induced (0.5 mM) increases in I_[sc], but did not affect increases in I_[sc] induced by serosal ACh (0.05 mM) or electrical field stimulation (EFS). Luminal addition of YM-254890 (10 μM), a Gα_[q/11]-selective inhibitor, markedly inhibited propionate-induced increase in I_[sc], but did not affect I_[sc] responses to ACh and EFS. Both methyl-β-cyclodextrin and YM-254890 significantly inhibited luminal propionate-induced non-neuronal release of ACh from colonocytes. Real-time PCR demonstrated that in mRNA expression of SCFA receptors, GPR 43 was far higher than that of GPR41 in the colon. Western blotting analysis revealed that the cholesterol-rich membrane microdomains that fractionated from colonic crypt cells were associated with caveolin-1, flotillin-1 and Gα_[q/11], but not GPR43. Uncoupling of Gα_[q/11] from flotillin-1 in lipid rafts occurred under desensitization of the I_[sc] response to propionate. Conclusions: These data demonstrate that the secretory response to luminal propionate in rat colon is mediated by G-protein on cholesterol-rich membrane microdomains, provably via Gα_[q/11].

Eighteen species of bacteria were screened for abilities to adsorb thorium and uranium. High thorium-adsorbing ability was observed in Arthrobacter nicotianae and Micrococcus luteus, and high uranium-adsorbing ability, in Arthrobacter nicotianae. The adsorption of both thorium and uranium by Micrococcus luteus cells was rapid, was affected by the solution pH, and was in competitive manner obeying the Langmuir adsorption isotherm for binary system taking the ionic charge of metal ion into account. The thorium selectivity in the competitive adsorption is assumed to be caused by the faster adsorption rate and the slower desorption rate of thorium than that of uranium., The original publication is available at www.springerlink.com

A theoretical derivation of condensation coefficient based on transition state theory is presented in this paper by considering the three-dimensional movement of condensing molecules in the liquid-vapor interface region. The theoretical expression is a function of free volume ratio of liquid to vapor and activation energy for condensation. We have developed an evaluation of the activated state conditions in the interface region with the use of molecular dynamics (MD) simulations for argon and water. From the molecular scale consideration, it is found that a characteristic length ratio (3)rootV(l)/V-g has an important role in evaluating the condensation coefficient because the restricted translational motion is dominant in the condensation process compared with the rotational motion. Present theoretical values agree well with MD results in both monatomic and polyatomic polar molecules. Finally, we conclude that the condensation coefficient is an inherent physical property of a given pure liquid-vapor interface and the interface structure plays a primary role in condensation. (C) 2003 American Institute of Physics.

A theoretical derivation of condensation coefficient based on transition state theory is presented in this paper by considering the three-dimensional movement of condensing molecules in the liquid-vapor interface region. The theoretical expression is a function of free volume ratio of liquid to vapor and activation energy for condensation. We have developed an evaluation of the activated state conditions in the interface region with the use of molecular dynamics (MD) simulations for argon and water. From the molecular scale consideration, it is found that a characteristic length ratio (3)rootV(l)/V-g has an important role in evaluating the condensation coefficient because the restricted translational motion is dominant in the condensation process compared with the rotational motion. Present theoretical values agree well with MD results in both monatomic and polyatomic polar molecules. Finally, we conclude that the condensation coefficient is an inherent physical property of a given pure liquid-vapor interface and the interface structure plays a primary role in condensation. (C) 2003 American Institute of Physics.

The study was conducted in order to understand a mechanism of interphase mass transfer between liquid and vapor. The molecular dynamics (MD) simulation is used to examine details of condensation and evaporation from the viewpoint of molecular kinetics. First, molecular boundary conditions for condensing, reflecting, and evaporating molecules are presented for an argon molecule as a function of the surface-normal component of translation energy. The velocity distributions can be expressed by the modified Maxwellian and making use of the condensation coefficient The condensation coefficient of water is also examined for two kinds of intermolecular potential, the Carravetta-Clementi (C-C) model and the extended simple point charge (SPC/E) model, in order to consider the effect of the surface structure of the liquid on the condensation coefficient. The results indicate that the condensation coefficient of water is close to unity for both models and its dependence on the translation energy is small compared with argon. Finally, the condensation coefficient is studied based on the transition-state theory. An evaluation of the transition state is considered by applying the results of MD simulations for argon and water.

The study was conducted in order to understand a mechanism of interphase mass transfer between liquid and vapor. The molecular dynamics (MD) simulation is used to examine details of condensation and evaporation from the viewpoint of molecular kinetics. First, molecular boundary conditions for condensing, reflecting, and evaporating molecules are presented for an argon molecule as a function of the surface-normal component of translation energy. The velocity distributions can be expressed by the modified Maxwellian and making use of the condensation coefficient The condensation coefficient of water is also examined for two kinds of intermolecular potential, the Carravetta-Clementi (C-C) model and the extended simple point charge (SPC/E) model, in order to consider the effect of the surface structure of the liquid on the condensation coefficient. The results indicate that the condensation coefficient of water is close to unity for both models and its dependence on the translation energy is small compared with argon. Finally, the condensation coefficient is studied based on the transition-state theory. An evaluation of the transition state is considered by applying the results of MD simulations for argon and water.

The study was conducted in order to understand a mechanism of interphase mass transfer between liquid and vapor. The molecular dynamics (MD) simulation is used to examine details of condensation and evaporation from the viewpoint of molecular kinetics. First, molecular boundary conditions for condensing, reflecting, and evaporating molecules are presented for an argon molecule as a function of the surface-normal component of translation energy. The velocity distributions can be expressed by the modified Maxwellian and making use of the condensation coefficient The condensation coefficient of water is also examined for two kinds of intermolecular potential, the Carravetta-Clementi (C-C) model and the extended simple point charge (SPC/E) model, in order to consider the effect of the surface structure of the liquid on the condensation coefficient. The results indicate that the condensation coefficient of water is close to unity for both models and its dependence on the translation energy is small compared with argon. Finally, the condensation coefficient is studied based on the transition-state theory. An evaluation of the transition state is considered by applying the results of MD simulations for argon and water.

Results are presented for gold recovery from aqueous solutions using immobilised persimmon tannin, and compared with results from various other biological substances. Persimmon tannin adsorbed gold from solutions containing hydrogen tetrachloroaurate (III) with high efficiency, but not from gold(I)sodium thiomalate or gold (I) dicyanourate. Adsorption of gold was rapid, and was affected by pH, temperature, external gold concentration, temperature, and amount of adsorbent. Adsorbed gold was easily desorbed with 1M thiourea solution, and results indicated that the immobilised persimmon tannin can be repeatedly reused., Results are presented for gold recovery from aqueous solutions using immobilised persimmon tannin, and compared with results from various other biological substances. Persimmon tannin adsorbed gold from solutions containing hydrogen tetrachloroaurate (III) with high efficiency, but not from gold(I)sodium thiomalate or gold (I) dicyanourate. Adsorption of gold was rapid, and was affected by pH, temperature, external gold concentration, temperature, and amount of adsorbent. Adsorbed gold was easily desorbed with 1M thiourea solution, and results indicated that the immobilised persimmon tannin can be repeatedly reused.

A study was carried out using 83 species of microorganisms (31 bacteria, 20 actinomycetes, 18 fungi and 14 yeasts). Bacterial strains such as Enterobacter aerogenes, Escherichia coli, Pseudomonas aureofaciens and Pseudomonas maltophilia showed high abilities to accumulate gold from solutions containing hydrogen tetrachloroaurate (III). Other microorganisms such as Streptomyces phaeochromogenus could accumulate gold from solutions containing sodium gold (I) thiomalate. However, most of the microorganisms accumulated only very small amounts of gold from solutions containing sodium dicyanoaurate (I). The highest gold accumulation was with Pseudomonas maltophilia in solutions containing hydrogen tetrachloroaurate (III). This was very rapid and was affected by solution pH and external gold concentration. Pseudomonas maltophilia cells immobilised in polyacrylamide gel showed an extremely high ability to adsorb gold. The gold is easily desorbed using 0.1 M thiourea solution. The immobilised Pseudomonas cells can be used repeatedly in the adsorption-desorption cycle., A study was carried out using 83 species of microorganisms (31 bacteria, 20 actinomycetes, 18 fungi and 14 yeasts). Bacterial strains such as Enterobacter aerogenes, Escherichia coli, Pseudomonas aureofaciens and Pseudomonas maltophilia showed high abilities to accumulate gold from solutions containing hydrogen tetrachloroaurate (III). Other microorganisms such as Streptomyces phaeochromogenus could accumulate gold from solutions containing sodium gold (I) thiomalate. However, most of the microorganisms accumulated only very small amounts of gold from solutions containing sodium dicyanoaurate (I). The highest gold accumulation was with Pseudomonas maltophilia in solutions containing hydrogen tetrachloroaurate (III). This was very rapid and was affected by solution pH and external gold concentration. Pseudomonas maltophilia cells immobilised in polyacrylamide gel showed an extremely high ability to adsorb gold. The gold is easily desorbed using 0.1 M thiourea solution. The immobilised Pseudomonas cells can be used repeatedly in the adsorption-desorption cycle.