Combined protein A imprinting and cryogelation for production of spherical affinity material

Cryogels have been demonstrated to be efficient when applied for protein isolation. Owing to their macroporous structure, cryogels can also be used for treating particle‐containing material, e.g. cell homogenates. Another challenging development in protein purification technology is the use of molecularly imprinted polymers (MIPs). These MIPs are robust and can be used repeatedly. The paper presents a new technology that combine the formation of cryogel beads concomitantly with making imprints of a protein. Protein A was chosen as the print molecule which was also be the target in the purification step. The present paper describes a new method to produce protein‐imprinted cryogel beads. The protein‐imprinted material was characterized and the separation properties were evaluated with regard to both the target protein and whole cells with target protein exposed on the cell surface. The maximum protein A adsorption was 18.1 mg/g of wet cryogel beads. The selectivity coefficient of protein A‐imprinted cryogel beads for protein A was 5.44 and 12.56 times greater than for the Fc fragment of IgG and protein G, respectively.     

Viscoelastic Timoshenko Beams with Occasionally Constant Relaxation Functions

For a prescribed desirable arbitrary decay suitable viscoelastic materials are determined through their relaxation functions. It is shown that if we wish to have a decay of order ??(t) then the kernels should be of the same order. That is their product with this function should be summable.     

Diffusion changes in patients with systemic lupus erythematosus

BACKGROUND AND PURPOSE: Systemic lupus erythematosus (SLE) is an autoimmune disease in which almost all the organs are involved. Neuropsychiatric SLE is of one of the major concerns in the clinical evaluation of this disease. Routine magnetic resonance imaging (MRI) findings are often nonspecific or negative. In this study, we explored the use of diffusion tensor imaging in assisting with the diagnosis of SLE. METHODS: Data from 34 SLE patients (age range, 18-73 years) and 29 age-matched volunteers (age range, 29-64 years) were analyzed. MRI was performed on a 1.5-T clinical MR scanner with a quadrature head coil. The average diffusion constant (D(av)) and diffusion anisotropy maps [fractional anisotropy (FA)] were determined on a pixel-by-pixel basis. Regional diffusion measurements were made by region of interest in the genu and splenium of the corpus callosum (CC), anterior and posterior limb of the internal capsule (IC) and frontal lobe and thalamus. The diffusion distribution was fitted to a triple-Gaussian model. The mean of the brain tissue distribution was determined as a mean diffusion constant for the whole brain (BD(av)). Student's t test was used to determine the diffusion difference between SLE patients and control subjects. The SLE patients were separated into two groups according to their MRI results. A P value lower than .05 was considered to be statistically significant. RESULTS: Twenty of the 34 SLE patients with abnormal MRI results showed findings dominated by nonspecific white matter disease. The BD(av) and D(av) values of the frontal lobe, splenium CC and anterior IC were significantly higher in all SLE patients as compared with the control subjects. The SLE patients with normal MRI results also showed higher BD(av) and D(av) values in the frontal lobe, splenium and anterior and posterior limbs of the IC as compared with the control subjects. There was no significant difference in the D(av) values of the thalamus between the SLE patients and the control subjects. The BD(av) value in the SLE patient group was robustly correlated with the D(av) values of the frontal lobe, splenium and thalamus. These correlations were found to be similarly significant for the SLE patients with normal MRI findings. The diffusion anisotropy measurements showed that splenium CC had the highest FA value in both the control subjects and SLE patients. Overall, SLE patients had lower FA values in the genu and splenium CC as compared with the control subjects. In the group of patients with normal MRI findings, the FA values of the genu and splenium CC as well as the anterior IC were also lower than those in the control subjects. Pearson's correlation statistics revealed robust correlations between the measurements of D(av) and FA values in the SLE patient group. CONCLUSION: Quantitative diffusion imaging and diffusion anisotropy showed early changes in the brains of the SLE patients. Increased BD(av) and D(av) values of the frontal lobe as well as decreased anisotropy in the genu CC and anterior IC may represent preclinical signs of central nervous system involvement of SLE even when the routine MRI findings are negative or nonspecific. Quantitative diffusion analysis may prove to be useful in detecting the initial brain involvement of SLE and may enable monitoring of early disease progression and treatment efficacy.     

Two new zinc(II) and mercury(II) complexes based on N,N′‐(cyclohexane‐1,2‐diylidene)bis(4‐fluorobenzohydrazide): synthesis,crystal structures and antibacterial activities

Reaction of N,N′‐(cyclohexane‐1,2‐diylidene)bis(4‐fluorobenzohydrazide), C₂₀H₁₈F₂N₄O₂, ( L^F ), with zinc chloride and mercury(II) chloride produced different types and shapes of neutral coordination complexes, namely, dichlorido[N,N′‐(cyclohexane‐1,2‐diylidene)bis(4‐fluorobenzohydrazide)‐κ²N,O]zinc(II), [ZnCl₂(C₂₀H₁₈F₂N₄O₂)], ( 1 ), and dichlorido[N,N′‐(cyclohexane‐1,2‐diylidene)bis(4‐fluorobenzohydrazide)‐κ⁴O,N,N′,O′]mercury(II), [HgCl₂(C₂₀H₁₈F₂N₄O₂)], ( 2 ). The organic ligand and its metal complexes are characterized using various techniques: IR, UV–Vis and nuclear magnetic resonance (NMR) spectroscopies, in addition to powder X‐ray diffraction (PXRD), single‐crystal X‐ray crystallography and microelemental analysis. Depending upon the data from these analyses and measurements, a typical tetrahedral geometry was confirmed for zinc complex ( 1 ), in which the Zn^II atom is located outside the bis(benzhydrazone) core. The Hg^II atom in ( 2 ) is found within the core and has a common octahedral structure. The in vitro antibacterial activities of the prepared compounds were evaluated against two different bacterial strains, i.e. gram positive Bacillus subtilis and gram negative Pseudomonas aeruginosa bacteria. The prepared compounds exhibited differentiated growth‐inhibitory activities against these two bacterial strains based on the difference in their lipophilic nature and structural features.     

The decay rate for a fractional differential equation

We consider the fractional differential equation

     

Poly(p‐phenylene methylene)‐based block copolymers by mechanistic transformation

The synthesis of poly(p‐phenylene methylene) (PPM)‐based block copolymers such as poly(p‐phenylene methylene)‐b‐poly(ε‐caprolactone) and poly(p‐phenylene methylene)‐b‐polytetrahydrofuran by mechanistic transformation was described. First, precursor PPM was synthesized by acid‐catalyzed polymerization of tribenzylborate at 16 °C. Then, this polymer was used as macroinitiators in either ring‐opening polymerization of ε‐caprolactone or cationic ring‐opening polymerization of tetrahydrofuran to yield respective block copolymers. The structures of the prepolymer and block copolymers were characterized by GPC and ¹H NMR investigations. The composition of block copolymers as determined by ¹H NMR and TGA analysis was found to be in very good agreement. The thermal behavior and surface morphology of the copolymers were also investigated, respectively, by differential scanning calorimetry and atomic force microscopy measurements, and the contribution of the major soft segment has been observed. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

A kinetic investigation of removal of chromium from aqueous solutions with a strong cation exchange resin

A kinetic investigation was performed with an ion exchange resin for chromium. A strong cation exchange resin (Amberlite IR 120) was used for removal of chromium. The effects of concentration, resin amount, and stirring speed on kinetics were investigated. The metal concentration range studied was between 5 to 160 mg/dm³ (the amount of solution was 4 dm³), the resin amount range was between 5 to 20 mg, and the stirring speed range was between 1000 to 3500 rpm. Equilibrium experiments were performed for calculation of separation factor. Kinetic studies were done using a Kressman-Kitchener stirrer reactor system and the results were compared with existing kinetic models. Two models, Nernst-Plank film diffusion control model (fdc) and solid phase diffusion control model (pdc), respectively were identified, and the dependence of the rate on parameters such as solution concentration, resin amount, stirring speed, etc. was examined for each of them. The interpretation of these data shows that the system is probably controlled by both film and particle diffusion. Correspondence: Sevgi Kocaoba, Department of Chemistry, Faculty of Art and Science, Yildiz Technical University, Davutpasa Cad. No: 127, 34210 Davutpasa-Istanbul, Turkey.     

Highly sensitive spectrophotometric methods for the determination, validation and thermogravimetric analysis of antiulcer drugs, nizatidine and ranitidine in pure and pharmaceutical preparations

Two sensitive, simple and rapid UV and second order derivative spectrophotometric methods were developed for the determination of nizatidine and ranitidine hydrochloride in pure form and pharmaceutical preparations. For the first method, UV spectrophotometic method, nizatidine was determined at 325 nm and ranitidine at 325.5 nm with detection limits of 0.07 and 0.04 μg/mL, respectively. For the second method, the distances between two extremum values (peak-to-peak amplitudes), 328/356.5 nm for nizatidine and 326/357 nm for ranitidine were measured in the second order derivative-spectra. The detection limits were found to be 0.02 μg/mL for nizatidine and 0.016 μg/mL for ranitidine, respectively. The thermal analysis of the two drugs was studied by Thermogravimetric Analysis-Differential Scanning Calorimetry (TGA-DSC) techniques. Enthalpy changes were obtained 121.9 and 124.15 J/g for nizatidine and ranitidine, respectively. The proposed method was successfully applied to the analysis of pharmaceutical preparations. The results were in good agreement with those obtained using the reference method; no significant difference were found in the accuracy and precision as revealed by the accepted values of t- and F-tests.     

Spectrofluorimetric Determination and Validation of Biotin in Pure and Dosage Form via Derivatization with 4-Fluoro-7-nitrobenzofurazan

A simple and highly sensitive spectrofluorimetric method was developed for the determination of biotin in pure and dosage form. The method is based on the derivatization of biotin with 4‐fluoro‐7‐nitrobenzofurazan in borate buffer of pH 9.0 to yield a yellow, fluorescent product. The various chemical conditions that affected the reaction were studied. The method was validated for specificity, linearity, precision, accuracy, recovery and robustness. At optimized experimental conditions, a linear relationship between the fluorescence intensity of the concentration of biotin is observed in the range 45–450 ng/mL. Limit of detection and quantification were 0.038 and 0.114 ng/mL, respectively. The percentage mean recovery was 99.96. The proposed procedure was successfully applied to the determination of biotin in its dosage form with mean recovery of 101.23±1.22 for biotin tablets. The results obtained were in good agreement with those obtained by the reference method.     

Møller Energy-Momentum Distribution of Higher Dimensional Vaidya Space-Time

In this paper, we intend to clarify the energy-momentum problem of higher dimensional Vaidya space-time in the general theory of relativity. In this connection, Møller energy and momentum for the higher dimensional Vaidya space-time are evaluated in the frame of general relativity. We have obtained that the Møller energy distribution of higher dimensional Vaidya space-time is equal to zero, while the Møller momentum distribution of higher dimensional Vaidya space-time is not equal to zero.