Manipulation of protein fingerprints during on-column fluorescent labeling: protein fingerprinting of six Staphylococcus species by capillary electrophoresis

Bacterial proteomes were analyzed by use of electrophoretically mediated microanalysis (EMMA) and field-enhanced stacking. A water-soluble protein fraction was injected onto a capillary. Next, a fluorogenic reagent was injected and allowed to react with the protein mixture, producing fluorescent products that were separated by submicellar capillary electrophoresis and detected by laser-induced fluorescence. By use of a low-ionic strength sample buffer and a brief electrophoretic step, slow moving anionic proteins were stacked at the reagent-sample interface and were preferentially labeled. By reversing the order of sample injection and labeling reagent, fast moving cationic proteins were preferentially labeled. By adjustment of the sample buffer pH, proteins with different isoelectric points were selectively labeled. Electrophoresis fingerprints were generated for the water-soluble protein fraction from six Staphylococcus species. The protein patterns produced were species-specific and were used to construct a phylogenetic tree.     

膜催化研究II. 多孔无要膜的制备与表征及其反应器对甲醇脱氢反应的促进作用

采用溶胶-凝胶法制备了多孔氧化铝膜, 并通过DSC、TGA、SEM、N~2吸附和气体透过率测定等手段, 对膜的性能进行了表征。结果表明, 用这种方法制备的多孔氧化铝膜是一种均匀无裂痕和具有较窄孔径分布(约4nm)的膜材料。将此多孔氧化铝膜制成膜反应器后, 用于甲醇催化脱氢制甲醛的反应, 发现甲醇转化率比常规反应器有较大幅度的提高。同时首次尝试采用溶胶-凝胶法将催化活性组分直接负载到多孔氧化铝膜上, 从而得到了一种具有催化活性的多孔膜, 并考察了它的反应活性。文中对由这两种多孔膜及钯/陶瓷复合膜制成的反应器的特点进行了比较。     

Spectroscopic study on the crystal growth in gas evaporation: emission and absorption spectra from Cu smoke

Optical emission and absorption spectra from a growth zone in Cu smoke were measured by using a quartz prism spectrograph and a single-grating spectrophotometer. Atomic lines of Cu, band systems of Cu₂ were observed. Two new band systems with 0–0 band heads at 252.88 and 238.79 nm were found. The continuous spectra due to Rayleigh scattering by fine particles were also observed. Variations of density of various species as a function of vertical position were revealed.     

Increased sensitivity of autoantibody determination by coupled-particle light-scattering assay by poly(ethylene glycols)-modified beads

New kinds of coatings by using polyethylene glycols were studied and were applied to a qualitative homogeneous immunoassay that exploits the agglutination reaction for the detection of autoimmune antibodies in a complex matrix. We used a piece of new technology, the Copalis^™, which uses a special optical-sizing flow particle analysis and a semiconductor laser as a light source.

Polystyrene microbeads coated with the antigen were used as markers and were put in contact with the serum sample. Different polyethylene glycols were synthesised and tested, optimising the experimental parameters. Human serum specimens were evaluated and we obtained a higher sensitivity with good discrimination between negative and positive samples. All the experimental steps are easy, rapid and enable us to process many samples in a short period of time.     

Synthesis and photochemistry of side-chain liquid crystal polymers based on cinnamate esters

The syntheses of three methacrylate monomers with cinnamate ester side-chains and of a further monomer with a corresponding cinnamide side-chain are described. Two of the monomers, with isomeric structures, were thermotropic liquid crystals. Although the clearing points were very similar the crystal melting points differed by 8°C. One compound also exhibited a monotropic smectic phase, behavior not shown by its isomer. The other two monomers were not liquid crystalline. The monomers were polymerized by free radical polymerization, both as homopolymers and as copolymers with methyl methacrylate. In the case of one of the mesogenic ester monomers, copolymers with a cyanophenyl benzoate monomer were also prepared. Three of the four monomers formed thermotropic liquid crystalline homopolymers and the copolymers with the benzoate monomer were also liquid crystalline. The monomers were considered as photoactive components of polymeric liquid crystals. As a preliminary investigation of their photochemistry, copolymers with methyl methacrylate were prepared and irradiated in solution with a broad-band source. Under these conditions two of the materials show a facile photo-Fries rearrangement of the aryl cinnamate ester group. © 1992 John Wiley & Sons, Inc.     

Ring-modified carbon fiber microelectrodes and multi-microelectrode devices

Two new types of modified microelectrodes were used alone and in multi-microelectrode devices. Carbon fibers with diameters of 7.2 μm were modified either by electropolymerization, or by thermal polymerization of a mixture of monomers to give a thick coating of modifier around the cylindrical fiber. The modified fibers were then coated with an insulating layer. The tips of the electrodes were polished perpendicular to the axis of the fiber to give ring-modified disk electrodes. Copolymers of poly(vinylferrocene) and poly(vinylpyridine) with crosslinked polystyrene were used, and demonstrated behavior similar to that for surface modified electrodes, except that the electrodes could be polished to renew the surface. Multi-microelectrode devices were prepared. For example, a ring-modified working electrode, a silver/silver chloride coated practical reference electrode, and a platinum auxiliary electrode were used in a molded epoxy probe in electrolyte solution to give cyclic voltammograms that were similar to those expected for a ring-modified working electrode using traditional reference and auxiliary electrodes.     

Analysis of endosulfan isomers and endosulfan sulfate in air and tomato leaves by gas chromatography with electron-capture detection and confirmation by gas chromatography-mass spectrometry

Rapid analytical methods for the determination of endosulfan isomers and endosulfan-sulfate in air and plant samples were developed. The insecticides were trapped from air using a column containing Florisil and extracted with a low volume of ethyl acetate, assisted by sonication. Pesticide residues were determined by gas chromatography with electron-capture detection using a nonpolar capillary column. Residue identities were confirmed by gas chromatography coupled with mass spectrometry. Recoveries of these compounds from air samples were always higher than 78% with an RSD lower than 11% and the detection limits obtained were at least 0.3 ng/l air. Leaf samples were homogenised with ethyl acetate and extracts cleaned-up on an aluminium oxide column. Pesticides were eluted with a hexane-ethyl acetate (80:20, v/v) mixture. Recoveries obtained from plant samples were higher than 78% with an RSD lower than 14% and detection limits in leaves were 0.02 microg/g for each pesticide. These methods were applied to study the volatilisation of endosulfan from tomato leaves under laboratory conditions. A volatilisation rate near 1% of the initial amount of endosulfan per hour was obtained during the first 24 h at room temperature.     

Heterocyclic-fused benzopyrans as cannabinoid analogues

A series of A-ring heterocyclic analogues of tetrahydrocannabinol were investigated. Chromanones 1a and 1b were functionalized by formylation with base and ethyl formate to give 6a and 6b. These formylketones were reacted with hydrazine, and Phenylhydrazine to give pyrazoles 7a,b,e , and f , respectively. When 6a and 6b were reacted wtih methylhydrazine, mixtures of methyl isomers 7c and 8a and 7d and 8b formed in a ratio of 1:2.5. Isoxazoles 10a and 10b formed similarly when hydroxylamine was used as the condensing agent. Attempts to prepare the pyrimidine derivatives 11 were thwarted by the rearrangements of 6a and 6b to chromenones 12a and 12b.     

新型含1,2,4-三唑基的1,5-苯并硫氮杂的合成和表征

以α-溴代苯乙酮为原料,在三乙胺作用下制备α-(1,2,4-三唑-1-基)-芳基乙酮(1a～1c),再与芳香醛发生羟醛缩合反应制备相应的含三唑基的查尔酮2a～2l,将中间体2a～2l同邻氨基硫酚合成新型的2,4-二芳基-3-(1,2,4-三唑-1-基)-2,3-二氢-1,5-苯并硫氮杂(3a～3l).所得化合物的结构经元素分析,IR,MS和1HNMR确认,同时用X射线衍射法测定了化合物2a和3a的晶体结构.     

Large-scale purification of antisense oligonucleotides by high-performance membrane adsorber chromatography

Very high flux ion-exchange membranes were utilized for a novel purification of antisense oligonucleotides (20-mer). Strong anion-exchange membranes were produced by attaching polymeric ligands onto a microporous cellulosic matrix. The oligonucleotides purified were therapeutic single-stranded phosphorothioates deoxyribonucleotides. Although small-scale membrane devices (15 cm2) had similar resolution to traditional chromatographic columns; their throughputs were superior. Greater than a 1300-fold scale-up produced very similar purity and yields of the phosphorothionate product. Scale-up experiments were conducted with a 2 m2 surface area membrane module. These modules were easily capable of very high throughputs of 0.5 to 2 l/min. High purity and yields were achieved by both step and linear gradient elution.     

Analysis of sewage sludge and cover soil by neutron activation analysis

The Korean government reported that in 2005, 4395 tons/day of sewage sludge were generated from sewage disposal facilities in Korea and only 11.03% of it was reused. In addition, as a direct landfill of sewage sludge was forbidden from June 2003, research for a relevant disposal technique has been increasing. In this study, the aims were to analyze the collected sewage sludge samples and to evaluate the possibility for their reuse by a comparison of the elemental contents from a sewage sludge and a cover soil. Sludge samples were collected from a sewage disposal plant in Daejeon city and the cover soil was produced by a dilution of a sewage sludge with quicklime. Instrumental neutron activation analysis was employed to determine the elemental contents in the samples. Twenty seven elements were analyzed and their concentrations were compared.     

Influence of the intercalated cations on the surface energy of montmorillonites: consequences for the morphology and gas barrier properties of polyethylene/montmorillonites nanocomposites

Organically modified montmorillonites obtained by cation exchange from the same natural layered silicate were studied. The surface properties of the pristine and a series of organically modified clays were determined by inverse gas chromatography and the water adsorption mechanisms were studied by a gravimetric technique coupled with a microcalorimeter. A significant increase of the specific surface area, a decrease of the water adsorption, and a decrease of the dispersive component of the surface energy were observed when the sodium cations of the natural montmorillonite were exchanged for a quaternary ammonium. Slighter differences in surface properties were observed, on the other hand, between the different types of organically modified montmorillonites. Indeed, similar dispersive components of the surface energy were determined on the organoclays. Nevertheless, the specific surface area increased in the range 48-80 m(2)/g with increasing d-spacing values and the presence of specific groups attached to the quaternary ammonium, such as phenyl rings or hydroxyl groups, led to some specific behaviors, i.e., a more pronounced base character and a higher water adsorption at high activity, respectively. Differences in interlayer cation chain organization, denoted as crystallinity, were also observed as a function of the nature of the chains borne by the quaternary ammonium. In a later step, polyethylene-based nanocomposites were prepared with those organically modified montmorillonites. The clay dispersion and the barrier properties of the nanocomposites were discussed as a function of the montmorillonite characteristics and of the matrix/montmorillonite interactions expected from surface energy characterization.     

Two pairs of chlorine-containing phenylpropanoid enantiomers from Acorus tatarinowii

Two pairs of chlorine-containing phenylpropanoid enantiomers (1a/1b and 2a/2b) were isolated from the rhizomes of Acorus tatarinowii. Interestingly, these optical isomers (1a/1b and 2a/2b) were co-existed in the same plant, which were characterized as the first halogen-containing natural products from the genus Acorus. Their structures and absolute configurations were elucidated by a combination of spectroscopic analysis and a single-crystal X-ray diffraction, assisted by a modified Mosher's method. The phenylpropanoid isomers (1a/1b and 2a/2b) were evaluated for their antioxidant activities using DPPH assay and cytotoxic activities against five human cancer cell lines.     

Investigation of airborne particles by inductively coupled plasma emission spectrometry calibrated with monodisperse aerosols

An emission spectrometric method for the investigation of airborne particles has been developed. Sample air was directly introduced into an ICP to vaporize and atomize the particles and to excite the atoms or ions. The emission signal from the ICP was observed as a flash for each particle when the particle concentration was sufficiently low. The flashes were converted into electric pulses, which were counted by a pulse height analyzer. Thus, for particles of homogeneous composition the particle concentration and size distribution were determined simultaneously for a given element. To calibrate the measuring system, monodisperse aerosols were prepared by using a vibrating orifice monodisperse aerosol generator. Sodium chloride, calcium nitrate and copper nitrate aerosols were generated using solutions of known concentrations. The concentration and size distribution of copper particles were determined in aerosols generated by a small arc at the switch of a lamp socket when a 200-W lamp was turned off. Most of the particles were less than 1μm in diameter with a peak distribution at 0.7 μm. The smallest particles measurable for calcium oxide and copper were 0.1 and 0.3 μm in diameter, respectively.     

Formation and plasmonic response of self-assembled layers of colloidal gold nanorods and branched gold nanoparticles

The plasmonic properties of self-assembled layers of rod- and branched-shaped gold nanoparticles were investigated using optical techniques. Nanoparticles were synthesized by a surfactant-guided, seed-mediated growth method. The layers were obtained by gradual assembly of nanoparticles at the interface between a polar and a nonpolar solvent and were transferred to a glass slide. Polarization and angle-dependent extinction measurements showed that the layers made of gold nanorods were governed by an effective medium response. The response of the layers made by branched gold particles was characterized by random light scattering. Microscopic mapping of the spatial mode structure demonstrates a uniform optical response of the nanoparticle layers down to a submicrometer length scale.     

Syntheses and antifungal activities of dl-griseofulvin and its congeners. I

dl-Griseofulvin (1a) was prepared by two synthetic pathways. New 6'-congeners (3 and 4) of griseofulvin were also prepared. Their antifungal activities were evaluated and compounds 3 and 4 were found to be less active than 1a. Molecular calculations on 1a, dl-epigriseofulvin (1b), 3 and 4 were undertaken.     

High-performance liquid chromatography of fat-soluble vitamins: separation and identification of vitamins D2 and D3 and their isomers in food samples in the presence of vitamin A, vitamin E and carotene

Vitamins D2 and D3 and their corresponding previtamins and provitamins were resolved by reversed-phase high-performance liquid chromatography using a ternary solvent system (acetonitrile-methanol-water) pumped according to a gradient elution programme. The D vitamins were also resolved in the presence of other lipid-soluble vitamins (A, E and K1) and carotene. The peaks were monitored with a UV-visible variable-wavelength detector and were detected at their maximum absorbance, resulting in maximum sensitivity. Lipid-soluble vitamins and carotene were resolved in extracts obtained from oils and butter, thus permitting their identification in a single chromatographic run.     

Comparison of surface modification techniques used for the preparation of wall coated open tubular glass capillary columns

Summary Comparison of different techniques for modifying internal glass surfaces to accept a substrate loading on wall coated open tubular columns (WCOT) were examined. Inner surfaces pretreated with a non-extractable Carbowax 20M layer, barium carbonate and silica whiskers were prepared and coated with a Carbowax 20M liquid phase. The columns were evaluated for efficiency, acidic-basic and adsorption properties, thermal stability and coating efficiency. Column performances were also assessed for deactivated surfaces. Each column was applied to a standard mixture of Aroclor 1016.     

Syntheses of Hitherto Unknown Thiazole,Ylidene and Pyridinethione Derivatives Having a Piperidin‐1‐yl Moiety and Their Use as Antimicrobial Agents

The novel hydrazone derivatives 2a‐c were prepared by treatment of aldehydes 1a,b with some hydrazines. Thiocarbamoyl functional group in compound 2a was subjected to cyclization reactions with some α‐halocarbonyl reagents and furnished the novel thiazoles 4‐6 , 8 and 9 . Enaminonitrile 10 and pyridinone 13 derivatives were synthesized by interaction of active methylene compound 2b with N,N‐dimethylformamide‐dimethylacetal and ketene dithioacetal 11 , respectively. Aliphatic, aromatic and heteroaromatic active methylene compounds were condensed with aldehydes 1a,b to afford the new ylidenes 15a‐d , 19a,b , 20 and 21 . Substituted pyridinethiones 22 and 23 were prepared in high yields by cyclocondensation of 15c with malononitrile and ethyl cyanoacetate, respectively. Indeno[1,2‐b]pyridines 26a,b were obtained by the reaction of ylidenes 19a,b with cyanothioacetamide in ethanol and in the presence of sodium ethoxide under reflux. The structures of the synthesized compounds were established from their analytical and spectral data. The prepared compounds were also screened for their antimicrobial activity.     

Changes in the mechanical properties of tooth-colored direct restorative materials in relation to time

The objective of this study was to determine the flexural strength, flexural modulus, Vickers hardness of a packable composite (Surefil), and an ormocer (Definite) in comparison with a microhybrid composite (Z-100), a microfil composite (Silux Plus) and a polyacid-modified composite resin (Dyract). Flexural strength and flexural modulus were determined using a three-point bending device. Microhardness was measured with a Vickers indentor. The specimens of each material were prepared according to manufacturer's instructions. The specimens were stored in artificial saliva at pH 6, all at 37°C. The groups were tested at the beginning of the test, at 3 months and at 6 months. Flexural strength values of Surefil and Definite showed a progressive increase. The highest MPa values were determined for Surefil (134.4 MPa) and the lowest MPa values were obtained for Dyract (59.6 MPa). The highest flexural modulus values were revealed for Surefil (10.000 GPa). Z-100, Silux Plus and Definite showed a tendency to decline in relation to time for their flexural modulus. GPa values of Silux Plus were stable at 3 and 6 months. Vickers hardness numbers showed that Surefil was the hardest and Dyract was the weakest material. Copyright © 2003 John Wiley & Sons, Ltd.