A New Bacteriophage-Modified Piezoelectric Sensor for Rapid and Specific detection of Mycobacterium

Detection of tuberculosis and related diseases caused by mycobacteria is costly, time-consuming, and labor-intensive. Here a new phage-modified piezoelectric system for rapid and specific detection of mycobacteria was developed. In this system, interdigital gold electrode immobilized with lytic phage was used as a probe in place of a steel electrode in the multi-channel series piezoelectric quartz crystal (MSPQC) system. The probe was directly connected to the piezoelectric detection system. Mycobacterium was specifically captured to the phage-modified electrode and then lysed by immobilized phage, which caused the electrode electrical properties change. This change can be sensitively monitored by the piezoelectric detection system. The detection time of Mycobacterium smegmatis was less than 2 hours and a detection limit of 10³cfu mL^?1 was obtained. Additionally, it was successfully used to detect Mycobacterium tuberculosis. The developed system using phage-modified interdigital electrode showed high specificity and reproducibility for mycobacterium detection. Compared with the MSPQC system, the proposed system was faster and more specific.     

Design of an on-line monitoring system for radioactive wastewater

An on-line monitoring system for radioactive wastewater was designed to discriminate the type and concentration of the radionuclides discharged from nuclear facilities. An HPGe semiconductor was used as the detector in the system for continuous monitoring by pumping wastewater. The minimum detectable activity for ¹³⁷Cs was 0.4 Bq L⁻¹ after 10 min of measuring wastewater with the system. The system can detect excessive radioactivity in the wastewater and quickly and effectively alert personnel. Based on the experimental measurements and the Monte Carlo simulation, the detection efficiency of the system was calibrated, and an efficiency curve was determined for the energy range from 50 to 2754 keV.

     

Development of a switchable multidimensional/comprehensive two-dimensional gas chromatographic analytical system

In this study, a new system for analysis using a dual comprehensive two-dimensional gas chromatography/targeted multidimensional gas chromatography (switchable GC × GC/targeted MDGC) analysis was developed. The configuration of this system not only permits the independent operation of GC, GC × GC and targeted MDGC analyses in separate analyses, but also allows the mode to be switched from GC × GC to targeted MDGC any number of times through a single analysis. By incorporating a Deans switch microfluidics transfer module prior to a cryotrapping device, the flow stream from the first dimension column can be directed to either one of two second dimension columns in a classical heart-cutting operation. Both second columns pass through the cryotrap to allow solute bands to be focused and then rapidly remobilized to the respective second columns. A short second column enables GC × GC operation, whilst a longer column is used for targeted MDGC. Validation of the system was performed using a standard mixture of compounds relevant to essential oil analysis, and then using compounds present at different abundances in lavender essential oil. Reproducibility of retention times and peak area responses demonstrated that there was negligible variation in the system over the course of multiple heart-cuts, and proved the reliable operation of the system. An application of the system to lavender oil, as a more complex sample, was carried out to affirm system feasibility, and demonstrate the ability of the system to target multiple components in the oil. The system was proposed to be useful for study of aroma-impact compounds where GC × GC can be incorporated with MDGC to permit precise identification of aroma-active compounds, where heart-cut multidimensional GC-olfactometry detection (MDGC-O) is a more appropriate technology for odour assessment.     

A study of the catalytic behavior of phosphotungstic acid-modified Janus particles in a heterogeneous oil/water pickering emulsion system

An emulsion interface materialization method was used to obtain amphiphilic silica Janus nanoparticles. Reducing the photosynthesis of aquatic organisms after water pollution. PW₁₂O₄₀³⁻ was introduced onto Janus particles by ion exchange, and an amphiphilic particle emulsion catalyst (PWO-J) was prepared. Hydrogen peroxide was used as the oxygen source, and the amphiphilicty of the catalyst was used to assemble the catalyst at the Pickering emulsion interface. The PWO-J catalyst was found to exhibit very high catalytic activity toward the oxidation of oleic acid in water-in-oil systems. The results showed that PWO-J catalysis of oxidation had similar results as CTAB and phosphotungstic acid (control system) under the same conditions. The azelaic acid recovery rate was 86.7%, and PWO-J could be reused 4 times. A reaction mechanism was proposed, and the constructed model was used to calculate a reaction rate constant of 15.32 × 10⁻⁵L•mol⁻¹•s⁻¹ for the PWO-J system. The PWO-J system had a lower activation energy than the control system, showing that the catalytic oxidation of oleic acid into azelaic acid was more likely to occur in the PWO-J system.     

Performance evaluation of ion‐exchange chromatography in capillary format

The performance of a recently introduced capillary ion‐exchange chromatography system was explored. Experiments were conducted in isocratic mode with a commercial capillary anion‐exchange column (id = 0.4 mm, L = 15 cm) using a five‐anion standard mixture. The achieved results were compared to the performance of a standard bore ion‐exchange system (id = 4 mm, L = 15 cm), which was considered as a reference. The first‐generation capillary columns exhibited a minimal reduced plate‐height value below two witnessing a good packing quality and system performance. However, compared to the standard bore system the capillary system displayed an increased apparent C‐term which could be due to a difference in packing morphology and/or possible external band‐broadening contributions. For fast separations, the standard bore system outperformed the capillary system, while for complex separations both systems performed nearly equally well. In addition, the retention characteristics of the capillary system were investigated. To illustrate the suitability of the capillary system, the analysis of real‐world water samples originating from two local Belgian rivers was demonstrated.     

Sensor System Based on Acetylcholinesterase in Homogenous Phase for Analysis of Paraoxon

Abstract

An amperometric sensor system based on acetylcholinesterase (AChE) was used for a paraoxon assay. Paraoxon-inhibited AChE resulted in the decrease of acetylthiocholine hydrolysis and the further oxidation of thiocholine on a platinum electrode. Thus described, the system allows for the detection of 1.2 ppb of paraoxon responding to absolute 12 pg. The sensor system functionality was verified on spiked beverages. The practical impact of system was summarized and future implementation is expected.     

Tree of phases of the Li,Na,Ba‖F,Br quaternary reciprocal system and study of the LiF-NaBr-BaFBr stable triangle

The Li,Ba‖F,Br ternary reciprocal system was investigated by differential thermal analysis. The T-x diagrams of the polythermal sections studied and the liquidus of the system were constructed. It was deter-mined that the system is of the adiagonal section type with a subordinate diagonal (according to Bergman’s classification). The characteristics and enthalpies of melting of the alloys corresponding to invariant equilibrium points were found. The Li,Na,Ba‖F,Br quaternary reciprocal system was partitioned, and the tree of phases was constructed. The LiF-NaBr-D₁(BaFBr) stable triangle was experimentally studied, the liquidus was constructed, and the characteristics of the alloy corresponding to a ternary eutectic were determined.     

Continuous monitoring for cyanide in waste water with a galvanic hydrogen cyanide sensor using a purge system

A continuous monitoring system for cyanide with a galvanic hydrogen cyanide sensor and an aeration pump for purging was developed. Hydrogen cyanide evolved from cyanide solution using a purging pump was measured with the hydrogen cyanide sensor. The system showed good performance in terms of stability and selectivity. A linear calibration curve was obtained in the concentrating range from 0 to 15 mg dm³ of cyanide ion with a slope of −0.24 μA mg⁻¹ dm⁻³. The lower detection limit was 0.1 mg dm⁻³. The 90% response time of the sensor system was within 3.5 min for a 0.5 mg dm⁻³ cyanide solution, when the flow rate of the purging air was 1 dm³ min⁻¹. The system maintained the initial performance for 6 months in the field test. The developed galvanic sensor system was not subject to interference from sulfide and residual chlorine, compared with a potentiometric sensor system developed previously. The analytical results obtained by the present system were in good agreement with those obtained by the pyridine pyrazolone method. The correlation factor and regression line between both methods were 0.979 and Y=2.30×10⁻⁴+1.12X, respectively. This system was successfully applied for a continuous monitoring of cyanide ion in waste water.     

Real-time imaging of radioisotope labeled compounds in a living plant

We developed a quantitative, real-time imaging system of labeled compounds in a living plant. The system was composed of CsI scintillator to convert β-rays to visible light and an image intensifier unit (composed of GaAsP semiconductor and MCP; micro channel plate) to detect extremely weak light. When the sensitivity and resolution of the image of our system was compared with that of an imaging plate (IP), the sensitivity of our system (with 20 minutes) was higher than that of an IP, with similar quality to that of an IP. Using this system, the translocation of ³²P in a soybean plant tissue was shown in successive images. Shared first authors.     

表柔比星-镁体系与DNA相互作用初步研究

表柔比星是临床上用于治疗快速增殖肿瘤的药物。本文应用紫外、荧光、圆二色、黏度、凝胶电泳等方法研究了表柔比星-Mg2+体系与DNA的作用。结果发现:在pH=7.4时,表柔比星可与Mg2+形成稳定体系。加入DNA后表柔比星-Mg2+体系的紫外吸收明显降低;Scatchard图表明表柔比星-Mg2+体系对溴化乙锭(EB)与DNA的结合为竞争性抑制;同时此体系可使DNA-EB体系荧光偏振度增大;使DNA的热变性温度(Tm)上升;黏度增大;凝胶电泳表明表柔比星-Mg2+体系对pBR322DNA有非常好的切割活性;圆二色谱法表明随着表柔比星-Mg2+体系的加入,DNA碱基间作用能迅速减弱,二级结构发生了显著的变化。综上所述:表柔比星-Mg2+体系与DNA之间为嵌插作用;且表柔比星-Mg2+体系具有更好的切割活性。这些结果,可为合理改善药效和设计新药提供依据。     

Studies of cyclohexane/TX 100 + ethylpropionate/water system: effect of ethylpropionate as cosurfactant

 Pseudoternary phase diagram of cyclohexane/TX 100-ethylpropionate/water system was determined at 30 ^°C. One phase microemulsion was obtained over a small area. The surfactant/cosurfactant ratio was both kept at 1:1 and 1:2 w/w. Viscosity, conductance, adiabatic compressibility values at various temperatures show the expected trend. The addition of NaCl changes one phase microemulsion to Winsor II system and no Winsor III system was obtained. Contact angle data, conductance, etc., show oil continuous system at a constant surfactant weight fraction. The microstructure of Winsor IV microemulsion seems to be W/O. Received: 14 May 1996 Accepted: 23 October 1996     

Enhancement of peroxyoxalate chemiluminescence intensity by surfactants and its application to detect detergent

Enhancement of peroxyoxalate chemiluminescence (PO-CL) intensity by a surfactant in the H₂O₂/bis(2,4,6-trichlorophenyl)oxalate (TCPO)/rhodamine B system was described. The effects of 15 surfactants were evaluated by comparing the ratio of a relative CL intensity (RCI) with surfactant to that of the blank in each system. In preliminary study, H₂O₂/imidazole-HNO₃ buffer/TCPO/rhodamine B system was used to study the effects of surfactants on PO-CL intensity. Fourteen surfactants reduced the CL intensity at the 2% concentration, where their relative CL intensities ranged from 0.6 to 93.5%. Some of these phenomena may be caused by a notable change of pH that was occurred by adding the surfactant.Additionally, enhancement of PO-CL intensity was studied by using system (1) H₂O₂/TCPO/rhodamine B and (2) H₂O₂/imidazole-HNO₃ buffer/TCPO/systems. In the system 1, the favorable enhancement of CL intensity (ranged from 124 to 472%) was observed with 9 surfactants at the 0.5% concentration. This result suggested that several surfactants might play a role as a catalyst in the PO-CL reaction. There was no tendency to enhance CL intensity among the surfactant types. In the system 2, the enhancement of CL intensity was also observed by adding with 11 surfactants, which might be mainly caused by the fluorescent impurities of surfactants used.Furthermore, detection of detergent commercially available was applied by using the system 1.     

The impact of different antifreeze agents on the thermal properties of ethylene vinyl acetate emulsion

The application of pour point depressants in the form of emulsions provides an alternative to overcoming the problem of handling during applications in cold climate environments. The incorporation of antifreeze agents to these emulsions helps to improve their cold flow properties, without sacrificing much of the other properties. This study considered the effect of the incorporation of different antifreeze agents into ethylene vinyl acetate emulsions that are used as pour point depressants. The results obtained revealed that the ethylene glycol (EG) emulsion system gave the lowest freezing temperature of −45°C, while the propylene glycol emulsion system provided the lowest vitrification temperature of −64°C. The size of the particles in the emulsion was significantly reduced from 359.1 nm to 207.4 to 216.4 nm when an antifreeze agent was used in the emulsion compared to the control sample (pure water). As for the selection of the most suitable antifreeze for the emulsion system, the vitrification performance was a factor that was taken into consideration in the decision to select the EG system due to the fact that this system offered an adequate performance in terms of vitrification efficiency at around −59°C, although it was not as excellent as the vitrification efficiency portrayed in the propylene glycol system. However, the EG emulsion system was the most suitable system for the ethylene vinyl acetate emulsion, as it delivered the best protection against freezing and, at the same time, produced a decent particle size distribution.     

Improved microfluidic chip-based sequential-injection trapped-droplet array liquid-liquid extraction system for determination of aluminium

An improved microfluidic chip-based sequential-injection trapped-droplet array liquid-liquid extraction system with chemiluminescence (CL) detection was developed in this work. Two recess arrays were fabricated on both sides of the extraction channel to produce droplet arrays of organic extractant. A chip integrated monolithic probe was fabricated at the inlet of the extraction channel on the glass chip instead of the capillary probe connected to the microchannel, in order to improve the system stability and reliability. A slotted-vial array system coupled with the monolithic probe was used to sequentially introduce sample and different solvents and reagents into the extraction channel for extraction and CL detection. The performance of the system was demonstrated in the determination of Al³⁺ using Al³⁺-dihydroxyazobenzene (DHAB) and tributyl phosphate (TBP) extraction system. The operation conditions, including extraction time, concentration and flow rate of the CL reagents, were optimized. Within one analysis cycle of 12 min, an enrichment factor of 85 was obtained in the extraction stage with a sample consumption of 1.8 μL. The consumption of CL reagent, bis(2-carbopentyloxy-3,5,6-trichlorophenyl)oxalate (CPPO), was 120 nL/cycle. The detection limit of the system for Al³⁺ was 1.6 × 10⁻⁶ mol/L with a precision of 4.5% (R.S.D., n = 6).     

Treatment of coke plant wastewater by A/O fixed biofilm system

The long-term environmental impacts of wastewa-ter from coke plant can be very high, especially due to the discharge of large amounts of wastewater. The composition of coke plant wastewater is complicated and varies from one factory to another, depending …     

An enhancement on electrical properties of carboxymethyl cellulose-NH4Br based biopolymer electrolytes through impedance characterization

In this work, the formulation of biopolymer electrolytes (BEs) system has been accomplished by incorporating various plasticizers with carboxymethyl cellulose–NH₄Br through solution casting technique. The ionic conductivity at room temperature of BEs system was achieved at ～10^?4 S cm^?1 with addition of 25?wt% NH₄Br and enhanced to ～10^?3 S cm^?1 when plasticizers were added. The temperature-dependence of the BEs system exhibits Arrhenius behavior. Jonschers power law was used to study the electrical properties and shows that the highest conducting BEs system can be represented by overlapping overlapping a large polaron tunneling model for poly(ethylene glycol) system a, small polaron hopping model for glycerol system, and a quantum mechanical tunneling model for ethylene carbonate system.     

Bias reduction in the quantitative analysis of a target analyte present in a limited quantity in human plasma using dual-mode heart-cutting two-dimensional liquid chromatography coupled with isotope dilution mass spectrometry

Dual-mode heart-cutting two-dimensional liquid chromatography (DMHC 2D-LC) was applied to isotope dilution mass spectrometry (IDMS) to reduce the bias in the quantitative analysis of a target analyte present in a limited quantity in human plasma. Based on a Waters I-Class LC system, the DMHC 2D-LC system was operated in one- and two-dimensional modes to facilitate the determination of heart-cutting time and the efficient trapping of the target LC eluate. Experiments to determine the feasibility of coupling with IDMS were performed with triple quadrupole mass spectrometry using folic acid standards and/or ¹³C₅-folic acid. To validate the performance of the DMHC 2D-LC/IDMS system on a complex sample, human plasma was analyzed for folic acid and the result was compared with that obtained using conventional single-column LC. The total run time of the DMHC 2D-LC system was 20 min, the same as that of the single-column LC system. The peak profile of the spiked ¹³C₅-folic acid obtained with single-column LC/MS was affected by matrix effects, but resolved with DMHC 2D-LC/MS, thus improving the accuracy of the analysis. The DMHC 2D-LC/IDMS system showed reliable performance in analyzing the target analyte in human plasma, eliminating matrix effects and saving analysis time.     

Simple Hexagonal-Pulsed-Field Gel Electrophoresis System

Abstract

A diode array was used to isolate point electrodes in a hexagonal-pulsed-field gel electrophoresis system. The electric circuit around the electrophoresis chamber was simplified by modification. The reasonably straightmigration and good resolution of large DNA molecules were observed by the system.

Several types of pulsed-field gel electrophoresis system have been developed to get straight DNA migration^1-5. We have adopted diodes to isolate     

Comparison of liquid chromatography-microchip/mass spectrometry to conventional liquid chromatography–mass spectrometry for the analysis of steroids

The feasibility of a microfluidic-based liquid chromatography-electrospray ionization/mass spectrometric system (HPLC-Chip/ESI/MS) was studied and compared to a conventional narrow-bore liquid chromatography-electrospray ionization/mass spectrometric (LC-ESI/MS) system for the analysis of steroids. The limits of detection (LODs) for oxime derivatized steroids, expressed as concentrations, were slightly higher with the HPLC-Chip/MS system (50–300 pM) using an injection volume of 0.5 μL than with the conventional LC-ESI/MS (10–150 pM) using an injection volume of 40 μL. However, when the LODs are expressed as injected amounts, the sensitivity of the HPLC-Chip/MS system was about 50 times higher than with the conventional LC-ESI/MS system. The results indicate that the use of HPLC-Chip/MS system is clearly advantageous only in the analysis of low-volume samples. Both methods showed good linearity and good quantitative and chromatographic repeatability. In addition to the instrument comparisons with oxime derivatized steroids, the feasibility of the HPLC-Chip/MS system in the analysis of non-derivatized and oxime derivatized steroids was compared. The HPLC-Chip/MS method developed for non-derivatized steroids was also applied to the quantitative analysis of 15 mouse plasma samples.     

Thioether-mediated copper transport through liquid membranes with the aid of redox reaction

A thioether-mediated copper transport with the aid of redox reaction was studied in a polymer-supported liquid membrane and in a liquid surfactant membrane. A photochemical generation of the redox potential led to a photo-assisted copper separation and concentration system. Tetradentate thioethers 1 and 2 (L) selectively extracted copper ion into organic solution in the presence of a reducing agent, and served as a copper-selective carrier in a liquid membrane system. In the polymer-supported organic liquid membrane system, the thioether was dissolved in the membrane phase which separated the two aqueous solutions of different redox potentials. The copper ion was extracted into the membrane phase by formation of the [Cu^IL]⁺ ? X^? type complex on the reducing solution interface and permeated through the membrane toward the oxidizing solution interface, where the complex was decomposed to release the copper(II) species into the oxidizing aqueous solution. The nature of the system was studied in detail under various operational conditions (redox agents, pairing anion X^?, coexisting metals, etc.) and compared with that of the previously reported Bathocuproine-mediated system. The transport system was extended to the water-in-oil-in-water emulsion system (liquid surfactant membrane), and the selective concentration of copper ion from dilute external aqueous solutions into inner stripping solutions was achieved. Photo-induced redox reactions, triethanolamine—acriflavine—methyl viologen—hv and glucose—titanium oxide—hv, were successfully coupled to the systems, leading to a photo-assisted copper transport in the polymer-supported liquid membrane as well as in the liquid surfactant membrane. Tentative explanations were given on the nature of the membrane transport reactions.