Selection of the optimum construction of column for the periodic rectification

The periodic rectification was considered from standpoint of recovery of the valuable component from the waste products of pharmaceutical manufacture. On the bases of a suggested mathematical simulation we developed an algorithm of computation and selection of an optimum configuration of a rectifying column of periodic action in the stage of designing. An effect of an exhaustion degree and making a distillate stronger on operating costs was examined in the determine example.     

Controlling the radiation degradation of carboxymethylcellulose solution

In this study, the effects of an irradiation on the viscosity of the carboxymethylcellulose (CMC) solution were investigated, and the methods to control the degradation of the CMC caused by an irradiation were developed. The viscosity of the CMC solution was decreased with an increase in the irradiation dose, but the extent of the degradation by an irradiation was found to decrease with an increase in the CMC concentration in the solution. The dependency of the irradiation sources showed that an electron beam radiation had degraded the CMC less severely than a gamma ray radiation. An addition of vitamin C as a radical scavenger to the solution was shown to be effective in preventing the decrease of the viscosity of the solution. Also, in the case of an irradiation at −70 °C, the decrease of its viscosity was efficiently inhibited. The degradation of CMC in the solution was confirmed by the molecular weight distribution.     

Acceleration of the Passerini reaction in the presence of nucleophilic additives

An accelerating effect of nucleophilic additives was revealed for the Passerini multi-component reaction. The influence of aqueous solutions on the reaction rate was studied in detail and the direct involvement of water in the bond-making step was attributed as the basis of an accelerating effect. Other nucleophiles were tested as alternatives to water; as a result N-hydroxysuccinimide is proposed as an accelerant of the Passerini reaction.     

The influence of the surface preparation on the electrodeposition of gold particles on silicon

In a systematical study of the electrodeposition of gold (I) on silicon (100), the influence of the surface preparation on the nucleation behavior of gold was investigated. A two-phase experimental design was used. In the first phase, it was investigated whether there is an influence; in the second phase, an optimization was performed. It was found that more homogeneous particle coverages and higher particle densities can be obtained when the surface is dipped in an acid fluoride solution with small nitric acid to hydrogen fluoride proportions. Furthermore, the observations indicated that more negative deposition potentials also lead to better coverages, higher densities, and less clustering.     

Channel shape effects on the solution-flow characteristics and the liquid/liquid extraction efficiency in polymer microchannel chips.

A polymer microchannel chip with a symmetrical or unsymmetrical zigzag-side-walled structure was fabricated by an imprinting method, and applied to study shape effects on solution flow characteristics as well as on the liquid/liquid extraction efficiency of an aluminium(III) chelate complex (Al-DHAB: DHAB = o,o'-dihydroxyazobenzene) in a microchannel chip. In an unsymmetrical zigzag-side-walled channel chip (us-channel), an oil/water interface was sinusoidal, while that in a symmetrical zigzag-side-walled channel chip (s-channel) was flat as long as the observation was made under an optical microscope. It was demonstrated that the efficiency of the water-to-oil (1-butanol) extraction of Al-DHAB in the microchannel was governed by the contact time between the two phases. As the most important results, furthermore, the extraction efficiency was higher in the us-channel, as compared with that in the s-channel, owing to the sinusoidal liquid/liquid interfacial structure and, therefore, to the high interfacial area between the two phases.     

On the properties of alpha-glucosidase and the binding of glucose to the enzyme.

An alpha-glucosidase was purified from baker's yeast. The molecular weight was approximately 44 000 daltons. SDS-disc gel electrophoresis suggested that the enzyme consisted of four subunits. The isoelectric point was at pH 5.4. The Km values for p-nitrophenyl alpha-D-glucopyranoside and maltose were 2.9 X 10(-4) and 2.5 X 10(-2) M, respectively. Binding of 2-(p-toluidino)naphthalene-6-sulfonate to the alpha-glucosidase was associated with a strong increase in fluorescence. The dissociation constant of the enzyme-TNS complex was 8 X 10(-5) M. The fluorescent probe did not interfere with the binding of glucose to the enzyme although the alpha-glucosidase was inhibited by high concentrations of TNS. The formation of an enzyme-glucose complex was indicated by an increase of fluorescence and by a shift in the wavelength for maximal emission which suggests that the binding process is associated with a change in conformation. The dissociation constant of the glucose--alpha-glucosidase complex KD = 0.57 X 10(-3) M, was calculated from the increase in fluorescence as a function of glucose concentration.     

Dependence of the efficiency of a capillary column in gas chromatography on the relative pressure of the carrier gas

The effect of relative pressure on the efficiency of an open capillary column in gas chromatography was studied. It was shown that the relative pressure was not the only parameter determining the column efficiency. The pressure drop in the column is an additional parameter. At high values of relative pressure, the pressure drop in the column becomes determining for the column efficiency. The smallest value of a height equivalent to a theoretical plate (HETP) is achieved at the minimum values of the pressure drop and the relative pressure, which is accompanied by a decrease in the optimal flow rate of the carrier gas and an increase in the time of determination. The maximum improvement in the column efficiency is determined by the column properties and can exceed 12.5%, that is, the value predicted by Cramers for open capillary columns.     

Effect of Mechanochemical Activation on the Catalytic Properties of Ferrites with the Spinel Structure

It was found experimentally that stacking defects formed in the mechanochemical activation of zinc ferrite enhanced the specific catalytic activity in the reaction of CO oxidation. The specific rate of CO oxidation was a linear function of defect concentration, which was determined using Mössbauer spectroscopy and X-ray diffraction. A conclusion was drawn that the same centers are responsible for an increase in the catalytic activity, the sorption capacity for hydrogen sulfide, and the reactivity of zinc ferrite in the interaction with hydrochloric acid. It was assumed that analogous factors caused an increase in the catalytic activity and reactivity of magnesium ferrite.     

Kinetic study of the degradation of a potential local anesthetic drug in serum using the DNA-based electrochemical biosensor

DNA-drug association interaction at the DNA modified screen-printed electrode for 1-methyl-2-piperidinoethylester of 2-hexoxyphenylcarbamic acid was found leading to an accumulation of the drug within the DNA layer. A procedure for the determination of drug in blood serum matrix using the protein precipitation and voltammetric measurement of the electroactive drug with the DNA biosensor was obtained and an effort was done to apply it for an assay of the drug enzymatic degradation in human and rabbit sera at 37 degrees C.     

Preliminary Ultrasonication Affects the Rate of the Bacteriorhodopsin Bleaching and the Effectiveness of the Reconstitution Process in Bacterioopsin

The formation process of polymer films based on bacteriorhodopsin (BR) analogs requests a high amount of BR samples one time only. The common technique for apomembrane formation (preparation of bacterioopsin, BO) is not designed to be operated with high concentrations and high volumes of BR, so the use of this technique results in a low rate of BR bleaching. To accelerate the process of BR bleaching preliminary sonication was used. It was used just as preliminary sonication before bleaching of BR samples, so also sonication was used before reconstitution of resulted BO samples. These modifications of the common technique lead to an acceleration of BR bleaching and an increase in effectiveness of reconstitution of BO in comparison with the nonmodified technique. The quantitative results of sonication's effect on the bleaching acceleration and the effectiveness of reconstitution are different depending on the BR strains.     

Influence of the phase composition of the support on the catalytic activity of bimetallic catalysts

The influence of the nanocrystalline structure of an aluminum-zinc spinel support on the catalytic activity of bimetallic Pt-Sn catalysts in dehydrogenation of 2-methylbutane was studied. The formation of the spinel structure in solid-phase reactions of aluminum and zinc oxides was examined.     

Study of the preparation of sustained-release microspheres containing zedoary turmeric oil by the emulsion-solvent-diffusion method and evaluation of the self-emulsification and bioavailability of the oil

The purpose of this study was to design a sustained-release formulation of an oily drug. The sustained-release microspheres with self-emulsifying capability containing zedoary turmeric oil (ZTO) were prepared by the quasi-emulsion-solvent-diffusion method. The micromeritic properties, the efficiency of emulsification and the drug-release behavior of the resultant microspheres were investigated. The bioavailability of the microspheres was compared with conventional ZTO self-emulsifying formulations for oral administration using 12 healthy rabbits. An HPLC method was employed to determine the concentration of germacrone in plasma, which was used as an index of ZTO. Spherical and compacted microspheres with average diameters of 100-600 microm have been prepared, and their release behavior in distilled water containing 1.2% (w/v) of polysorbate-80 can be controlled by the ratio of polymer/Areosil200 in the microspheres. The resultant emulsions with mean droplet sizes of 200-500 nm are produced when the microspheres are immersed in phosphate buffer (pH 6.8) under gentle agitation. The stability and the droplet size of the resultant emulsions are also affected by the polymer/Areosil200 ratio in the formulation, while the amount of talc has a marked effect on the self-emulsifying rate. The plasma concentration-time profiles with improved sustained-release characteristics were achieved after oral administration of the microspheres with a bioavailability of 135.6% with respect to the conventional self-emulsifying formulation (a good strategy for improving the bioavailability of an oily drug). In conclusion, the sustained-release microspheres with self-emulsifying capability containing ZTO have an improved oral bioavailability. Our study offers an alternative method for designing sustained-release preparations of oily drugs.     

Controlling the magnetic filaments length by tuning the particle interactions

Initially stable samples of monodisperse superparamagnetic particles were aggregated in the presence of an external magnetic field and different amounts of electrolyte. The aggregation process was monitored using dynamic light scattering (DLS). When the magnetic field was turned off, a significant change of the effective diffusion coefficient was observed at all electrolyte concentrations. This jump was interpreted in terms of filament break-up and additional rotational diffusive modes. Therefore, the length of the magnetic filaments (MF) was determined from the measured average diffusion coefficients applying an adequate theoretical approach. The results prove that the MFs disassemble completely at low electrolyte concentrations. At intermediate amounts of electrolyte added, a partial cluster break-up is observed. Only at high salt concentrations, the chains withstand the absence of the magnetic field. The results show that average filament size can be predicted and controlled by tuning the relative strength of the magnetic and electric interactions.     

Enantioselective synthesis of the AB-ring system of the antitumor antibiotic tetrazomine

The synthesis of the 1,2,3,4-tetrahydroisoquinoline moiety of tetrazomine was accomplished in 18 steps and in 3% overall yield from commercially available o-anisaldehyde. The reaction sequence utilizes a Sharpless asymmetric dihydroxylation to install the stereocenter and an intramolecular Friedel--Crafts hydroxyalkylation with an N-protected 2-oxo-acetamide to close the heterocyclic ring.     

Study of the Intramolecular Reaction of an Activated Phosphate Ester in the Micelle System Containing Macrocyclic Complex

The intramolecular nucleophilic substitution of an activated phosphate diester, bis(p-nitrophenyl) phosphate (BNPP) as the nucleic acids substitute, was investigated. A macro-cyclic ligand and the corresponding Cu (II) and Ni (II) complexes were synthesized and characterized. The metallomicelles made up of macrocyclic divalent metal complex and micelle, as mimic hydrolytic metalloenzyme, was used in BNPP catalytic hydrolysis. The metallomicelles displayed higher catalytic activity although they do not attain the catalytic efficiency of enzymes. The analysis of specific absorption spectra showed that the course of the BNPP catalytic reaction was different from that of the BNPP spontaneous hydrolysis, and was an intramolecular nucleophilic substitution reaction. Based on the analytic result of the specific absorption spectrum, an intramolecular nucleophilic substitution mechanism of BNPP catalytic hydrolysis was proposed and a correlative kinetic mathematical model was established, and the corresponding thermodynamic and kinetic constant was calculated. The result of this study proved validity of the mechanism and mathematical model proposed in the article.     

Mechanism of the reaction of arylamines with acridines in the presence of sulfur

The mechanism of the aminoarylation of acridines in the presence of sulfur was investigated. It was established that the process takes place in two steps: formation of an intermediate arylamine-acridine complex and oxidative dehydrogenation of the complex by sulfur. The second step probably is accomplished via an ionic mechanism.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1674–1677, December, 1970.     

Monoclonal antibody-based enzyme-linked immunosorbent assays for the detection of the organophosphorus insecticide diazinon

Four haptens of the organophosphorus (OP) insecticide diazinon were synthesized to develop enzyme-linked immunosorbent assays (ELISAs) for this pesticide. One of them was conjugated to KLH to be used as the immunogen for production of monoclonal antibodies. By using the antibodies and a coating antigen, an indirect competitive ELISA was developed, which showed an IC₅₀ of 4.0 ng/mL with a detection limit of 0.7 ng/mL. A direct competitive ELISA using an enzyme tracer was also developed, which showed an IC₅₀ of 6.0 ng/mL with a detection limit of 0.9 ng/mL. The antibodies in both assays showed negligible cross-reactivity with metabolites of diazinon and other OP pesticides. Recovery of diazinon from fortified lettuce and rice samples was satisfactory except at the fortified concentration of 100 ppb.     

An Electrochemical Study of the Ziegler - Natta Catalyst

Abstract

An anodic voltanmetric study was made of the Ziegler-Natta catalyst in tetrahydrofuran using a rotating platinum electrode. It was shown that these measurements could be used as an indication of the activity of the catalyst. It was also observed that the catalyst and the cocatalyst (diethyl aluminum chloride) formed an electrochemically inactive species. The study was complicated by the presence of an impurity (probably water) In the solvent that reacted with the catalyst and by the formation on the electrode of an inert film.     

Influence of water/alkoxide ratio in the synthesis of nanosized sol-gel titania on the release of phenytoin

The sol-gel method was used to synthesize inorganic reservoirs with encapsulated antiepileptic drug phenytoin. The drug release profile was shown to depend on the morphology and surface properties of the matrix. A parameter of the synthesis such as water/alkoxide ratio r(w) was varied in order to investigate its influence on the matrix properties and as a result on the drug release profile. It was found that the specific surface area and crystallization degree decrease with an increase of r(w), whereas the hydroxyl group coverage increases with an increase of r(w). Drug release kinetics studies revealed that the initial release rate increases with an increase of water content in the reaction, whereas the long time release rate first slightly increases with an increase of water content from 4 to 8 and then decreases for r(w) = 16. The interplay of different parameters of the matrix is shown to be responsible for such a dependence and is discussed in the Article.     

Contributions to the determination of histamine rate by measuring out the histamine-orthophthalaldehyde complex in the absorption and fluorescence

Histamine is an important compound from a physiological point of view, but it is toxic since the absorption of low amounts of histamine can cause abdominal pains accompanied with vomiting. Why we have developed a new method for histamine analysis in order to improve Lerke and Bell method. From the absorption spectra, we showed that the stoichiometry of the complex histamine-orthophthalaldehyde (OPA) is 1:1. From the emission spectra, it was observed that the complex fluorescence is inhibited in acidic medium. In alkaline medium, an exaltation of fluorescence was observed, but the complex histamine-OPA was unstable. Nevertheless, kinetic study showed that good linear correlations between the fluorescence maxima of the formed complex and the histamine concentration could be obtained in this alkaline medium.