Depletion of human lymphocytes from peripheral blood and bone marrow by affinity ligands conjugated to agarose—polyacrolein microsphere beads

Protein-A or goat anti-mouse-Ig (GAMIg) covalently bound to agarose-polyacrolein microsphere beads (APAMB) were employed for the removal of T cells from human peripheral blood leukocytes (PBL) and bone marrow (BM). The cell suspensions were treated with a monoclonal anti-T cell antibody (Leu-1) or monoclonal antilymphocyte antibody (CAMPATH-1) and passed through the conjugated APAMB columns. Cell separation efficacy was determined by assaying the number and function of T cells in the final cell preparation in comparison with a sample of unseparated cells. The number of cells that form rosettes (E-RFC) with sheep red blood cells (SRBC) in a sample of PBL treated with anti-Leu-1 antibodies and subsequently passed once through GAMIg-conjugated APAMB dropped from a range of 41.5–86.0% to a range of 1.6–13.3%. The in vitro response to concanavalin-A (Con-A) dropped to a range of 0.7–27.2% (GAMIg) and a range of 1.2–21.8% (protein-A column) of the response of untreated PBL. Treatment with CAMPATH-1 antibody and passage through a protein-A-conjugated APAMB reduced E-RFC from a range of 55.6–57.4% to a range of 3.2–3.9% and abolished the Con-A induced proliferative responsiveness to background levels. Treatment of BM cells with CAMPATH-1 and passage of the cells through either GAMIg or protein-A conjugated APAMB columns resulted in reduction of E-RFC from a range of 12.4–17.7% to a range of 0–1% and from a range of 17.7–19% to a range of 1.6–3.2%, respectively. Viability of BM precursors, determined by the CFU-GM assay in semisolid medium, was not affected by these cell separation procedures. The data suggest that protein-A or GAMIg-conjugated APAMB columns may be a useful tool for separation of BM cell suspensions into specific cell subsets that can be defined by monoclonal antibodies.     

Extending the dynamic range of the determination of copper by adsorption differential pulse stripping method using a principal component artificial neural network

A principal component artificial neural network (PC-ANN) has been applied for the analysis of the voltammogram data of Cu(II) and Cu(II)–PAN complex for extending the dynamic range of the determination of Cu(II) (5–550 μg/l). A three layer back-propagation network (6:5:1) was used with learning rate (r=0.09) and momentum (m=0.9), with sigmoidal transfer function in the hidden layer and one bias node in the input layer. Overall, the application of PC-ANN enables the extension of the dynamic range of the determination of Cu(II) from its narrow linear range (5–50 μg/l) to the high dynamic range (5–550 μg/l).     

Extending the dynamic range of copper determination in differential pulse adsorption cathodic stripping voltammetry using wavelet neural network

A wavelet neural network (WNN) model is proposed for extending the dynamic range of Cu(II) determination by differential pulse adsorption cathodic stripping voltammetry (DP-AdSV) using xylenol orange (XO) as a suitable ligand. All of voltammograms data consisting of Cu(II) and Cu(II)–XO peak currents were used in WNN model. The WNN model consisted of three layers (2-8-1) with the Morlet mother wavelet transfer function in the hidden layer. The model was able to extend the dynamic range of Cu(II) from its narrow linear range (1–50 ng ml⁻¹) to the higher dynamic range (1–1500 ng ml⁻¹). The results of the WNN model was also compared with artificial neural network (ANN) model and it was demonstrated the superiority of the WNN model relative to ANN model.     

A semiempirical long-range corrected exchange correlation functional including a short-range Gaussian attenuation (LCgau-B97)

We applied an improved long‐range correction scheme including a short‐range Gaussian attenuation (LCgau) to the Becke97 (B97) exchange correlation functional. In the optimization of LCgau‐B97 functional, the linear parameters are determined by least squares fitting. Optimizing μ parameter (0.2) that controls long‐range portion of Hartree‐Fock (HF) exchange to excitation energies of large molecules (Chai and Head‐Gordon, J Chem Phys 2008, 128, 084106) and additional short‐range Gaussian parameters (a = 0.15 and k = 0.9) that controls HF exchange inclusion ranging from short‐range to mid‐range (0.5–3 Å) to ground state properties achieved high performances of LCgau‐B97 simultaneously on both ground state and excited state properties, which is better than other tested semiempirical density functional theory (DFT) functionals, such as ωB97, ωB97X, BMK, and M0x‐family. We also found that while a small μ value (～0.2) in LC‐DFT is appropriate to the local excitation and intramolecular charge‐transfer excitation energies, a larger μ value (0.42) is desirable in the Rydberg excitation‐energy calculations. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011     

Preparation of new poly(ester triazole) and poly(amide triazole) by “click chemistry”

New dialkynyl monomers containing furan and ester or amide units were prepared via three step reactions from ethyl furan-2-carboxylate. Their click polymerization with either poly(ethylene glycol) diazide or poly(tetrahydrofuran) diazide catalyzed by Cu(I) led to corresponding amorphous poly(ester triazole) and poly(amide triazole) with molecular weights in the range of (7–11) × 10³ and with glass transition temperatures in the range of ?35 and ?19°C. The temperature at 5% wt loss (T ₁₀), determined from TGA of polyazomethines were in the range 345–365°C indicating their good thermal stability.     

Poly (Vinyl Chloride) Matrix Membrane Electrodes Responsive to Thiocyanate,Perchlorate and Periodate

Abstract

Three types of PVC matrix membrane ion-selective electrodes (ISEs) are described. These are based on membranes containing nitron thiocyanate with 2-nitro-phenyl phenyl ether, 2-nitrophenyl phenyl ether alone and tetraphenylarsonium thiocyanate with 2-nitrophenyl octyl ether. Each type is conditioned and stored in 0.1M sodium thiocyanate. The first two electrodes have been evaluated for thiocyanate and perchlorate response and the best linear long range (linear range down to 2.5×10^?5M) response was obtained for perchlorate. The third electrode is suitable as a periodate ISE with linear calibration range down to 2×10^?4M. The plasticized (2-nitrophenyl phenyl ether) PVC electrode for thiocyanate and perchlorate had a much longer pH interference free range (1.5–12.5) than either of the other electrodes.     

Graphene oxide reinforced polyamide nanocomposite coated on paper as a novel layered sorbent for microextraction by packed sorbent

ABSTRACT

In this work, a novel layered sorbent for microextraction by packed sorbent (MEPS) was introduced, which has been prepared by coating graphene oxide/polyamide (GO/PA) nanocomposite (NC) onto cellulose paper through solvent exchange method. Scanning electron microscopy (SEM) was applied to investigate the surface characteristic and morphology of PA and GO/PA NC coated on cellulose paper. The prepared MEPS device was used for extraction of organophosphorous pesticides (OPPs) including chlorpyrifos, fenthion, fenithrothion, ethion, edifenphos and phosalone in environmental aqueous samples followed by detection using gas chromatography-flame ionisation detector (GC-FID). Important parameters affecting the MEPS method including pH of sample solution, extraction draw-discard cycles, sorbent layers, desorption solvent volume and desorption draw-eject number were studied and optimised using central composite design (CCD). Based on the method validation, limits of detection (LODs) were in the range of 0.2–1 µg L^?1. The calibration graphs for chlorpyrifos, fenthion and edifenphos are linear in the concentration range of 1 to 500 µg L^?1; for ethion and phosalone are linear in the range of 1–1000 µg L^?1 and for fenithrothion is linear in the range of 3–1000 µg L^?1. The method precision (RSD %) with six replicates determinations was in the range of 3 to 9.4 % and 3.9 to 11.9% for distilled water and spiked river water sample, respectively, at the concentration level of 300 µg L^?1 . The developed method was applied successfully to determine OPP compounds in river, dam and tap water samples; accordingly, the relative recoveries (RR%) were obtained in the range of 77.8 to 113.3%.     

On the structure of glassy polymers. III. Small-angle x-ray scattering from amorphous polyethylene terephthalate

The small-angle x-ray scattering (SAXS) from glassy polyethylene terephthalate has been measured using a Bonse–Hart system. The data cover the angular range (2θ) between 20 sec and 2 deg. After correcting for absorption, background, and beam divergence, the data have been placed on an absolute basis by comparison with the scattering from a standard silica suspension. The corrected absolute intensity decreases strongly with increasing angle over the range between 20 sec and 15 min, decreases more gradually in the range between 15 min and 45 min, and reaches a nearly constant asymptotic value over the range between 45 min and 2 deg. The magnitude of the scattering in the constant range, about 0.4 (electrons)² Å^?3, is very close to the value predicted by the thermodynamic fluctuation theory for fluids applied at the glass-transition temperature [0.34 (electrons)² Å^?3]. The increase in intensity at angles smaller than about 45 min cannot be described by structures on the scale and volume fraction of the nodules reported in amorphous PET (50–100 Å), but can be well represented by small concentrations of heterogeneities, ranging in size from 100 to 2000 Angstroms, superimposed on the thermal density fluctuations frozen-in at the glass transition. The bulk structure of this material seems well described as a random amorphous solid, containing simple thermal fluctuations and a small concentration (<1 vol-%) of heterogeneities covering a range of sizes. The heterogeneities in the small end of the range may well be crystallites which formed on cooling.     

A rapid and precise method for the determination of oxygen in certain gases: Modified brady method

The modified brady method is a rapid one, requiring only about one hour for the analysis, but requires large samples of gas, 5 to 20 liters. The precision of the method described here-in is ± 0.004 to ± 0.4 in the low range of oxygen-concentration (0.01 to 0. 10 part per million oxygen),± 0.01 to ± 0.07 in the medium range of oxygen-concentration (0.1 to l .0 part per million oxygen)and ± 0.0 to ± 0.2 in the upper range of oxygen-concentration (1 to 15 parts per million oxygen). The liest precision (winkler method) previously reported was ± 0.3 part per million oxygen. The range of the method is 0.01 to 15 parts per million oxygen. The minimum amount of oxygen detectible is 0.005 part per million.     

Binuclear Complexes. II. Electron Paramagnetic Resonance Study of Binuclear Copper Complexes with α-Diimine Ligand

A series of biouclear copper (II) complexes containing a-diimine ligand has been synthesized and characterized by electron paramagnetic resonance spectroscopy. The copper complexes of the form [Cu(dien)D](ClO₄)₂ or [Cu2(dien)₂L](CIO₄)₄, where dien is diethylenetriamine, L' is monodentate ligand and L is bridging ligand, were studied. The EPR spectra were recorded in solution and frozen glassy solution. In the frozen solution spectra, the values of G‖ are in the range of 2.10 to 2.20, and the g⊥ are in the range of 2.03 to 2.06. Furthesmore, the values of A‖ are in the range of 170 to 188 gauss, and the A ⊥ are in the range of 17 to 32 gauss. The data indicate that the structure of Cu(II) complexes is axial symmetry in square pyramidal form.     

Evaluation of Viscosity-Molecular Weight Constant (K), Short Range Parameter (A) and Long Range Parameter (B) of Dextran in Polar Solvents

Abstract

The viscosity-molecular weight constant (K), the short range parameter (A) and long range parameter (B) have been evaluated in binary mixture of Dextran of three different molecular weights in three different solvents i.e., distilled water, 1(N) NaOH and 1(N) KOH, at temperatures ranging from 25°C to 50°C. The study reveals that the viscosity-molecular weight constant (K) decreases with increase in temperature for polar solvents. The short range parameter (A) shows the same trend as shown by K and the long range parameter (B) exhibits no definite trend with the variation of temperature.     

Spectrophotometric determination of manganese(VII) using benzyltriphenylphosphoniumchloride as a new reagent and application of artificial neural network to extending the dynamic range of determination

A simple and selective spectrophotometric method is proposed for the determination of trace amounts of manganese. The method is based on the extraction of manganese as a MnO₂-benzyltriphenylphosphoniumchloride ion pair with chloroform. An artificial neural network (ANN) has been applied to the handling of the spectrophotometric data of this complex in the organic phase to extend the dynamic range of manganese determination (0.020–6.0 μg/mL). A three-layer back-propagation network (50:75:1) was used with root-mean-square error (rmse) 0.001 and momentum (m) 0.8 overall. The application of BP-ANN makes it possible to extend the dynamic range of the determination of manganese from its narrow linear range of 0.020–2.5 μg/mL to the dynamic range 0.020–6.0 μg/mL. The text was submitted by the author in English.     

A test of comparative equilibration for determining non‐exchangeable stable hydrogen isotope values in complex organic materials

Comparative equilibration has been proposed as a methodological approach for determining the hydrogen isotopic composition (δD) of non‐exchangeable hydrogen in complex organic materials, from feathers to blood and soils. This method depends on using homogenized standards that have been previously calibrated for their δD values of non‐exchangeable H, that are compositionally similar to unknown samples, and that span an appropriate isotopic range. Currently no certified organic reference materials with exchangeable H exist, and so isotope laboratories have been required to develop provisional internal calibration standards, such as the keratin standards currently used in animal migration studies. Unfortunately, the isotope ratios of some samples fall outside the range of keratin standards currently used for comparative equilibration. Here we tested a set of five homogenized keratin powders as well as feathers from Painted Buntings and Dark‐eyed Juncos to determine the effects of extrapolating comparative equilibration normalization equations outside the isotopic range of keratin standards. We found that (1) comparative equilibration gave precise results within the range of the calibration standards; (2) linear extrapolation of normalization equations produced accurate δD results to ～40‰ outside the range of the keratins standards used (?187 to ?108); and (3) for both homogenized keratin powders and heterogeneous unknown samples there was no difference in variance between samples within and outside the range of keratin standards. This suggested that comparative equilibration is a robust and practical method for determining the δD of complex organic matrices, although caution is required for samples that fall far outside the calibration range. Copyright © 2009 John Wiley & Sons, Ltd.     

Synthesis of (Z)-N-alkenyl-β-arylselanyl imidazoles via additive-free nucleophilic addition of imidazole to arylselanylalkynes

We present herein our results on the nucleophilic addition of imidazole to a range of arylselanylalkynes by simple heating in DMF without any additives to give (Z)-1-(1-organyl-(2-arylselanyl)vinyl)-1H-imidazoles. The reactions were performed under mild conditions with a range of arylselanylalkynes in good yields and with high regio- and stereoselectivity to give the respective (Z)-arylselanyl alkene as the only isomer.     

Ambient temperature thermotropic liquid crystalline viologen bis(triflimide) salts

Two dicationic salts with bis(triflimide) as counterions exhibited crystal-to-smectic liquid crystalline phase transitions (T _m=41 and 37°C) and smectic-to-isotropic liquid phase transitions (T _i=112, 136°C). They had a broad liquid crystalline phase range (71–99°C) and an excellent range of thermal stability (360–364°C). Their mixtures of various compositions also displayed liquid crystalline properties from r.t. to an extended range of temperatures. They exhibited fluorescence in 1, 2-dimethoxyethane and methanol.     

Ambient temperature thermotropic liquid crystalline viologen bis(triflimide) salts

Two dicationic salts with bis(triflimide) as counterions exhibited crystal-to-smectic liquid crystalline phase transitions (T_m=41 and 37°C) and smectic-to-isotropic liquid phase transitions (T_i=112, 136°C). They had a broad liquid crystalline phase range (71-99°C) and an excellent range of thermal stability (360-364°C). Their mixtures of various compositions also displayed liquid crystalline properties from r.t. to an extended range of temperatures. They exhibited fluorescence in 1, 2-dimethoxyethane and methanol.     

等压法测定298.15K下LiCl-CaCl2-H2O体系的活度系数

电解质水溶液热力学性质的研究一直是一个很活跃的研究领域.对含锂水盐体系热力学性质的研究不仅对电解质水溶液理论,而且对盐湖锂资源的开放利用都有非常重要的意义.姚燕等对ＬｉＣｌＫＣｌＨ2Ｏ[1],ＬｉＣｌＭｇＣｌ2Ｈ2Ｏ[2],ＬｉＣｌＭｇＳＯ4Ｈ2Ｏ[3,4],ＬｉＣｌＬｉ2ＳＯ4Ｈ2Ｏ[5]体系多温下热力学性质进行了研究,应用Ｐｉｔｚｅｒ电解质水溶液理论模型进行处理,计算出ＬｉＣｌ在不同体系中,很大的浓度范围内的活度系数.但在盐湖卤水中,ＣａＣｌ2的存在很普遍.对ＬｉＣｌＣａＣｌ2混合物在水溶液中的热力学性质研究对理解ＬｉＣｌ在盐…     

Lower critical solution temperature and hydrophobic hydration in aqueous polymer solutions

Phase diagrams of aqueous solutions of poly(N-vinyl caprolactam) (PVCL), N-vinyl caprolactam copolymer with vinylamine (3.8 mol%) (CP(VCL-VA)), and poly(N-vinyl propylacetamide) (PVPA) were shown to be binodal curves with lower critical solution temperatures (LCST) in the range 304–313.5 K and critical concentrations in the range of 0.02–0.08 polymer weight fraction. Aqueous solutions of N-vinyl caprolactam copolymer with N-vinyl pyrrolidone (80 mol%) (CP(VCL-VP)) remained homogeneous in the entire region of the liquid state of water. The enthalpy of mixing with water of PVPA and CP(VCL-VP) was negative and the curve was concave over the entire range of composition at 298 and 308 K. The excessive heat capacity and partial heat capacity at infinite dilution of PVPA were positive, proving the hydrophobic character of hydration of this polymer. In contrast, these parameters were negative for CP(VCL-VP), revealing hydrophilic hydration. Hydrophilic hydration was predominant in solutions which were homogeneous over a wide temperature range, whereas hydrophobic hydration predominated in solution of polymers with LCST.     

Simplifying LR‐HSQC spectra using a triple‐quantum filter: The LR‐HTQC experiment

Long‐range heteronuclear single quantum correlation (LR‐HSQC) experiments may be applied for detecting long‐range correlations but suffer from two disadvantages, common to all heteronuclear long‐range correlation experiments: (i) The information density in LR‐HSQC spectra may be too high to be used directly without “filtering out” shorter range correlations, and (ii) often, substantial differences in intensity among cross peaks exist, potentially hampering the visualization of weak, often crucial cross peaks. In this contribution, we propose a modified LR‐HSQC experiment, the LR‐HTQC experiment (Long‐Range Heteronuclear Triple Quantum Correlation) that partially solves the problems aforementioned. We show theoretically and experimentally that the LR‐HTQC experiment removes the intense cross peaks of CH spin pairs, substantially reduces the medium intensity of cross peaks originating from CHH' spin systems, whereas the typically weak intensity of cross peaks of CHH'H″ and C(H)_n, _{n > 3} spin systems is less affected. Consequently, the LR‐HTQC experiment affords simplified long‐range heteronuclear shift correlation spectra and scales down large intensity differences among different types of cross peaks, although a certain general reduction of signal intensities has to be accepted.     

Two decades of high temperature gas chromatography (1983–2003): what's next?

The evolution of the concept of High Temperature High Resolution Gas Chromatography (HT-HRGC) is presented together with examples highlighting its potentialities. The range of molecular weight and number of functional groups present in the molecules eluting at higher temperature, far exceeds (Kovats Indices of 120) the usual HRGC range for analytes (Kovats Indices of 40–45). With usual column lengths and film thickness, this will already extend the range of analytes by 400 Da. Short, thin film columns would acme another 500 Da to the molecular weight window traditionally dealt with by HRGC.This range (700–1500 Da) can be surpassed by molecules presenting peculiar structures, the ceiling being 5000 Da. It is currently tackled only for peptides, oligosaccharides and a few polymers, by conventional analytical techniques. However, higher molecular weight analogues of all other organic species and yet unknown carbon skeletons have been neglected because this range was only poorly accessible to usual analytical techniques dealing with complex mistures.