毛细管超薄池光度吸附测量新技术

在毛细管超薄池光度检测中首次采用吸收光强测量新技术,显著提高了测量的灵敏度和改善了信噪比。在内径50μm的石英毛细管超薄池以及由石英光导纤维构成的十字交叉超薄光学吸收池上,分别测量了系列高锰酸钾溶液吸收光强。吸收光强与高锰酸钾溶液浓度之间呈现良好的线性关系。对于10μg/mL的高锰酸钾稀溶液,毛细管超薄池吸收光强测量的信噪比相对于吸光度测量的有较大的改善。十字交叉池的光程约为40μm,容积约为0.02μL,具有较大的光能量,可望发展成为一种新型的电泳光度检测池。     

毛细管超薄池光度吸附测量新技术

在毛细管超薄池光度检测中首次采用吸收光强测量新技术,显著提高了测量的灵敏度和改善了信噪比。在内径50μm的石英毛细管超薄池以及由石英光导纤维构成的十字交叉超薄光学吸收池上,分别测量了系列高锰酸钾溶液吸收光强。吸收光强与高锰酸钾溶液浓度之间呈现良好的线性关系。对于10μg/mL的高锰酸钾稀溶液,毛细管超薄池吸收光强测量的信噪比相对于吸光度测量的有较大的改善。十字交叉池的光程约为40μm,容积约为0.02μL,具有较大的光能量,可望发展成为一种新型的电泳光度检测池。     

A new hybrid electrospray Fourier transform mass spectrometer: design and performance characteristics

A new hybrid electrospray quadrupole Fourier transform mass spectrometry (FTMS) instrument design is shown and characterized. This instrument involves coupling an electrospray source and mass-resolving quadrupole, ion accumulation, and collision cell linear ion trap system developed by MDS Sciex with a home-built ion guide and ion cyclotron resonance (ICR) cell. The iterative progression of this design is shown. The final design involves a set of hexapole ion guides to transfer the ions from the accumulation/collision trap through the magnetic field gradient and into the cell. These hexapole ion guides are separated by a thin gate valve and two conduction limits to maintain the required <10(-9) mbar vacuum for FTICR. Low-attomole detection limits for a pure peptide are shown, 220 000 resolving power in broadband mode and 820 000 resolving power in narrow-band mode are demonstrated, and mass accuracy in the <2 ppm range is routinely available provided the signal is abundant, cleanly resolved, and internally calibrated. This instrument design provides high experimental flexibility, allowing Q2 CAD, SORI-CAD, IRMPD, and ECD experiments with selected ion accumulation as well as experiments such as nozzle skimmer dissociation. Initial top-down mass spectrometry experiments on a protein is shown using ECD.     

Assessment and validation of a screened Coulomb hybrid density functional

This paper presents a revised and improved version of the Heyd-Scuseria-Ernzerhof screened Coulomb hybrid functional. The performance of this functional is assessed on a variety of molecules for the prediction of enthalpies of formation, geometries, and vibrational frequencies, yielding results as good as or better than the successful PBE0 hybrid functional. Results for ionization potentials and electron affinities are of slightly lower quality but are still acceptable. The comprehensive test results presented here validate our assumption that the screened, short-range Hartree-Fock (HF) exchange exhibits all physically relevant properties of the full HF exchange. Thus, hybrids can be constructed which neglect the computationally demanding long-range part of HF exchange while still retaining the superior accuracy of hybrid functionals, compared to pure density functionals.     

Linear-dichroic infrared spectroscopy - validation and experimental design of the new orientation technique of solid samples as suspension in nematic liquid crystal

A validation of the developed new orientation method of solid samples as suspension in nematic liquid crystal (NLC), applied in linear-dichroic infrared (IR-LD) spectroscopy has been carried out using a model system DL-isoleucine (DL-isoleu). Accuracy, precision and the influence of the liquid crystal medium on peak positions and integral absorbances of guest molecules have been presented. Optimization of experimental conditions has been performed as well. An experimental design for quantitative evaluation of the impact of four input factors: the number of scans, the rubbing-out of KBr-pellets, the amount of studied compounds included in the liquid crystal medium and the ratios of Lorentzian to Gaussian peak functions in the curve fitting procedure on the spectroscopic signal at five different frequencies, indicating important specifities of the system has been studied.     

Detection and measurement of rheumatoid factor using a new immuonenzymatic technique with peroxidase/anti-peroxidase complex

A new, solid-phase enzymatic technique is proposed for the detection and measurement of rheumatoid factors (RF). A complex (PAP) consisting of peroxidase and rabbit IgG anti-peroxidase antibodies was used as antigen.The sensitivity of the technique is such that even ⪡ physiological ⪢ levels of RF may be detected in the majority of serum samples. The intra-assay and inter-assay repeatability (6–8% and 12%) is better than that for either of the traditional agglutination techniques (latex fixation test and Waaler-Rose reaction, or LWR) and this means that the serological evolution of the illness may be followed more accurately for each patient.The detection of non-agglutinating RF was also possible. The antigen used (i. e. rabbit IgG) was fixed immunologically to the enzyme, hence it was not denaturated by chemically labelling. This antigen resembles that of the Waaler-Rose reaction.A variation of this method enabled the detection of RF immunoglobulin class, when only the IgM fraction of the sera tested could be fixed to the solid phase by means of anti-μ F(ab′)₂ antibody before introduction of the antigen. The affinity constant could be measured without antibody purification.In 211 cases of adult rheumatoid arthritis, abnormally high levels of RF were revealed in 78 % of the subjects using the PAP technique and in only 53 % with the agglutination (LWR) techniques. On the other hand, the RF levels were within normal limits in the 51 cases of other inflammatory rheumatisms lacking RF according to the LWR techniques, in 62 cases of non-inflammatory diseases (hip osteoarthrosis, low back pain) and also in the 42 cases of other inflammatory diseases.     

Simple, new technique for measurement of fluorescence quantum yields: Application to benzene vapor

A new technique is presented for measuring fluorescence quantum yields without recourse to comparison with “standards”. The first experiments involved a study of benzene in the vapor phase. The measured fluorescence quantum yield at 2537 Å, Φ_F = 0.19 ± 0.02.     

Pervaporation-based hybrid process: a review of process design,applications and economics

Pervaporation is one of the developing membrane technologies that can be used for various industrial applications but for a predefined task, the optimal process design is unlikely to consist solely of pervaporation. Often the optimised solution becomes a hybrid process combining pervaporation with one or more other separation technologies. A distinction will be made between hybrid and integrated processes. Hybrid processes are important and consequently need to be considered in process design. This paper focuses on pervaporation–based hybrid processes that have been realised on an industrial scale. Both present and future prospects of applying these process combinations will be reviewed. The emphasis of this paper is, therefore, on pervaporation combined with distillation and with chemical reactors. The economic potential of these hybrid processes is evaluated, for various applications, by cost comparisons between the pervaporation-based hybrid processes and alternative separation processes. Pervaporation-based processes for waste water treatment and biotechnology applications involve other types of pervaporation based hybrid processes and have been excluded from this review.     

Thiol-derivatized porphyrins: synthesis and design of hybrid nanostructures

The review is devoted to the synthesis of thiol-derivatized porphyrins and hybrid nanostructures manufactured from them. Literature data on the main synthetic strategies towards these compounds are summarized, examples of application of thiol-derivatized porphyrins in nanotechnology are given.     

Experimental design approach in optimizing the sorption properties of a new generation of reinforced porous hybrid beads

A new sorbent called reinforced porous hybrid beads (RPHB) based on an Algerian aluminium pillared montmorillonite (Al-PIMt)/polyvinyl alcohol (PVA) and calcium carbonate (CC) was prepared using the extrusion method. These new composite bead sorbents were characterized by Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The mechanical properties for a series of wet RPHB are measured using uniaxial compression tests. These RPHB beads were used in the batch mode sorption of malachite green (MG) in aqueous solution.The effects of independent variables such as the initial concentration of MG, the sorbent dose and the pH of the suspension as well as their interactions during sorption processes are investigated. A Box–Behnken design based on the response surface methodology (RSM) is applied to evaluate the main effects of the variables. The response in term of the MG removal efficiency is maximized. The study of the interactions between the three variables shows that the initial concentration of MG and the pH of the aqueous media appear to be the most significant variables which significantly affect the elimination of MG. The optimal values favorable for the best sorption of MG on these new porous beads are an initial concentration of MG (92.36 mg L⁻¹), a pH of the aqueous medium (pH = 5.01) as well as the dose of the RPHB sorbent (1.03 g L⁻¹).Statistical analysis results show a good correlation between the experimental results and those predicted with a very satisfactory coefficient of determination value (R² = 0.99).     

FLUFF-BALL, a template-based grid-independent superposition and QSAR technique: validation using a benchmark steroid data set

The Flexible Ligand Unified Force Field (FLUFF) is a molecular mechanistic superposition algorithm utilizing a template structure, on top of which the ligand(s) are superimposed. FLUFF enables a flexible semiautomatic superimposition in which the ligand and the template are allowed to seek the best common conformation, which can then be used to predict the biological activity by Boundless Adaptive Localized Ligand (BALL). In BALL, the similarity of the electrostatic and van der Waals volumes of the template and ligand is evaluated using the template-based coordinate system which makes the FLUFF-BALL invariant as to the rotations and translations of the global coordinate system. When tested using the CBG (corticosteroid binding globulin) affinities of 31 benchmark steroids, the FLUFF-BALL technique produced results comparable to standard 3D-QSAR methods. Supplementary test calculations were performed with five additional data sets. Due to its high level of automation and high throughput, the FLUFF-BALL is highly suitable for use in drug design and in scanning of large molecular libraries.     

Molecular hexagonal perovskite: a new type of organic-inorganic hybrid conductor

An organic charge-transfer (CT) salt (BEDT-TTF)₃(MnCl₃)₂(C₂H₅OH)₂ has been synthesized by a standard electrochemical method. The crystal data are monoclinic, C2/c (#15), a=38.863(4)Å, b=6.716(1) Å, c=23.608(3) Å, β=115.007(3)°, V=5584(1) Å³, and Z=4. The structure consists of one-dimensional (1D) infinite {[MnCl₃]⁻}_∞ magnetic chains and two-dimensional (2D) organic conduction pathways. The former consists of face-sharing octahedra of manganese chloride complex ions, and dominates the magnetic properties of this compound. Such a feature of the crystal structure closely relates to transition metal hexagonal perovskite compounds, all of which are known for frustrated triangular lattices comprised of weakly interacting 1D magnetic chains. The new compound exhibits a high conductivity down to 4 K.     

The "resin-capture-release" hybrid technique: a merger between solid- and solution-phase synthesis

A polymer-assisted organic synthesis that combines the concept of solid-phase synthesis with the idea of polymer-supported scavenging reagents has recently appeared on the chemistry scene. This technique has frequently been termed the "resin-capture-release" methodology and is initiated by the immobilization of a small molecule on a polymeric support. This intermediate is subjected to a second transformation by adding a new reaction partner in solution. This reactant plays two roles: a) the chemical alteration of the polymer-bound intermediate and b) the simultaneous release of this reaction product from the resin back into solution. This new concept is presented and future prospects are discussed.     

A new technique for the measurement of the dynamic evolution of surface tension

We develop a novel technique which deduces the surface tension in air of a fluid as a function of surface age, beginning at age zero. The technique utilizes pointwise measurements of perpendicular free surface profiles of a steady oscillating jet corresponding to a discretization interval on the order of 0.1 ms. We implement the technique on constant-surface-tension test fluids (100% ethanol and 15% ethanol/85% water by volume) to demonstrate the extent to which the technique can qualitatively capture that the surface tensions of these fluids are constant in time, and quantitatively produce values of these constants consistent with static measurements. We then implement the technique on jets of two agricultural surfactant mixtures, Triton X-405 and Triton X-100, and quantitatively deduce the decay of surface tension as a function of surfactant concentration.     

Comment: Comment on “a new,versatile, three-pulse technique for the measurement of picosecond duration luminescent decay”

The method proposed by Mahr et al. is considered with respect to the influence of orientational relaxation on the measured signal.     

A new technique for the measurement of multicomponent gas transport through polymeric films

An apparatus to measure mixed gas permeation through polymer films is described. The system, based on a combination of manometric and gas chromatography techniques, allows straightforward determination of film permeabilities and selectivities over a wide range of feed pressures and compositions. This approach eliminates the need to use a downstream sweep gas and can be implemented by simple modification of pure gas permeation cells. Pure and mixed gas permeation data in polycarhonate films are reported for carbon dioxide and methane to illustrate the use of the equipment. The deviations between the pure and mixed gas results tend to be small and can he explained in terms of current theories of gas transport in glassy polymers.