H-1 NMR analysis for metabolites in serum and urine from rats administrated chronically with La(NO3)(3)

H-1 NMR spectroscopy has been used to assess long-term toxicological effects of a rare earth. Male Wistar rats were administrated orally with La(NO3)(3) at doses of 0.1, 0.2, 2.0, 10, and 20 mg/kg body wt, resp., for 3-6 months. Urine was collected at 1, 2, and 3 months and serum samples were taken after 6 months. Numerous low-M-r metabolites in rats serum and rats urine, including creatinine, citrate, glucose, ketone bodies, trimethylamine N-oxide (TMAO), and various amino acids, were identified on 400- and 500-MHz H-1 NMR spectra. La3+-induced renal and liver damage is characterized by an increase in the amounts of the excreted ketone bodies, amino acids, lactate, ethanol, succinate, TMAO, dimethylamine, and taurine and a decrease in citrate, glucose, urea, and allantoin. Information on the molecular basis of the long-term toxicity of La(NO3)(3) was derived from the abnormal patterns of metabolite excretions. An assay of some biochemical indexes and analysis of some enzymes in plasma supported NMR results.

Polymerized unsymmetrical iron post-metallocene catalyst for ethylene polymerization

The unsymmetrical allyl containing post-metallocene complex [ArN = C( Me)] [(ArN)-N-' = C(Me)]C5H3NFeCl2 [Ar = 2,6(i- Pr)(2)C6H3, Ar' = 4-allyl-2,6-(i-Pr)(2)C6H3] (3) has been prepared and characterized. Complex (3) can be co-polymerized with styrene in the presence of radical initiator to produce polymerized post-metallocene catalyst which exhibits high activity for ethylene polymerization (2.5 x 10(6) g PE/mol Fe.h).

Real-time immunoassay of antibody activity in serum by surface plasmon resonance biosensor

A surface plasmon resonance biosensor has been used to determine antibody activity in serum. As a model system, the interaction of mouse IgG and sheep anti-mouse IgG polyclonal antibody was investigated in real time. The factors, including pH value, ionic strength, protein concentration, influencing electrostatic adsorption of mouse IgG protein onto carboxylated dextran-coated sensor chip surface, were studied. The procedures of mouse IgG protein immobilization and immune reaction were monitored in real time. The regeneration effect using the different elution reagents was also investigated. The same mouse IgG immobilized surface can be used for 100 cycles of binding and elution with only 0.38% loss per regeneration in reactivity. The results show that the surface plasmon resonance biosensor is a rapid, simple, sensitive, accurate and reliable detection technique for real-time immunoassay of antibody activity. The assay allows antibodies to be detected and studied in their native form without any purification. (C) 2000 Elsevier Science B.V. All rights reserved.

Detection of anti-human serum albumin antibody using surface plasmon resonance biosensor

The biosensor based on surface plasmon resonance(SPR) technology is a very useful tool to study the interaction between biomolecles. The main advantages of this technique is to "visualize" macromolecular interactions directly in real time, and in a label-free mode rather than indirect methods like enzyme-linked immunosorbent assays (ELISAs). We immobilize human serum albumin (HSA) to the carboxymethyldextran-modified sensor chip surface covalently to detect the activity of anti-HSA in serum, and regenerate the surface with .1 mol/L phosphoric acid. The results show that SPR biosensor can detect the activity of anti-HSA in real-time quickly and the sensor chip can be used over 100 cycles.

Studies of Gd-diethylenetriamine pentaacetic acid in boving serum albumin solution by nuclear magnetic resonance spectroscopy

In this paper, the water relaxation enhancement behavior of Gd-diethylenetriamine pentaacetic acid(DTPA) in water and in aqueous solution of bovine serum albumine(BSA) has been studied. The T-1 relaxivity of Gd-DTPA in BSA solution is higher than that in aqueous solution. The results indicate that Gd-DTPA can integrate non-covalently with BSA mainly in forms of (Gd-DTPA) . BSA, (Gd-DTPA)(2) . BSA, for which the apparent equilibrium constant is 0.026 mmol(-1).L,0.0018 mmol(-2).L-2 respectively. This method would be used to study the interactivities between protein and contrast agent.

Electric field-induced conformational transition of bovine serum albumin from alpha-helix to beta-sheet

The irreversible conformational transition of bovine serum albumin (BSA) from alpha-helix to beta-sheet, induced by electric field near the electrode surface, was monitored by circular dichroism (CD) with a long optical path thin layer cell (LOPTLC).

Allyl containing iron post-metallocene catalyst for ethylene polymerization

Tridentate ligand[(2,6-ArN=C(Me))(2)C5H3N](Ar=4-allyl-2,6-(i-Pr)(2)C6H3)(4)which contains allyl groups on each aryl ring was ready prepared and reacted with FeCl2. 4H(2)O to give the precatalyst [(2,6-ArN=C(CH3))(2)C5H3N]. FeCl2 (5). Compounds 2-5 were characterized by H-1 NMR, EI-MS,and IR. The complex 5 which was actived by methylaluminoxane(MAO) exhibits high activity for ethylene polymerization [1.9 x 10(6) g pE.(mol Fe . h)(-1) at 0 degreesC]. It was showed that the activity was decreased with increasing temperature and the polymer product was highly linear PE with (M) over bar (eta) varying from 50000 to 260000.

Gold-coated iron (Fe@Au) nanoparticles: Synthesis, characterization, and magnetic field-induced self-assembly

A unique reverse micelle method has been developed to prepare gold-coated iron (Fe@Au) nanoparticles. XRD, UV/vis, TEM, and magnetic measurements are utilized to characterize the nanocomposites. XRD only gives FCC patterns of gold for the obtained nanoparticles. The absorption band of the Fe@Au colloid shifts to a longer wavelength and broadens relative to that of the pure gold colloid. TEM results show that the average size of Fe@Au nanoparticles is about 10 nm, These nanoparticles are self-assembled into chains on micron scale under a 0.5 T magnetic field. Magnetic measurements show that the particles are superparamagnetic with a blocking temperature (T-B) of 42 K, At 300 K (above T-B), no coercivity (Hc) and remanence (M-r) is observed in the magnetization curve, while at 2K (below T-B) He and M, are observed to be 728 Oe and 4.12 emu/g, respectively, (C) 2001 Academic Press.

The electrochemically induced conformational transition of disulfides in bovine serum albumin studied by thin layer circular dichroism spectroelectrochemistry

The conformational transition of disulfides in bovine serum albumin (BSA) induced by electrochemical redox reaction of disulfides were monitored by in-situ circular dichroism (CD) spectroelectrochemistry, with a long optical path thin layer cell and analyzed by a singular value decomposition least square (SVDLS) method. Electrochemical reduction of disulfides drives the left-handed conformation of disulfides changed into the right-handed. At open circuit, eight of the 17 disulfides were of left-handed conformation. Four of the 17 disulfides took part in the electrochemical reduction with an EC mechanism. Only one-fourth of the reduced disulfides returned to left-handed conformation in the re-oxidation process. Some parameters of the electrochemical reduction process, i.e. the number of electrons transferred and electron transfer coefficient, n=8, alphan=0.15, apparent formal potential, E-1(0') = -0.65(+/-0.01) V, standard heterogeneous electron transfer rate constant, k(1)(0) = (2.84 +/- 0.14)x 10(-5) cm s(-1) and chemical reaction equilibrium constant, K-c=(5.13 +/- 0.12) x 10(-2), were also obtained by double logarithmic analysis based on the near-UV absorption spectra with applied potentials. (C) 2001 Elsevier Science B.V. All rights reserved.

Simultaneous spectrophotometric determination of trace iron (III) and aluminum (III) with hybrid linear analysis

Hybrid linear analysis (HLA) was applied to resolution of overlapping spectra of Fe3+-salicylfluorone and Al3+-salicylfluorone complexes and simultaneous spectrophotometric determination of Fe3+ and Al3+. The absorbance matrix of 7 standard mixtures at 41 measuring points ranged from the wavelength of 550 nm to 630 nm was used for calibration. To avoid the effect of interaction between the two components on the determination, the column vector of K matrix obtained from the standard mixtures with least squares was used as the pure spectrum of component. The recoveries of the two elements for the analysis of the synthetic samples were 93.3% similar to 107.5% in the range of the concentration ratio of Fe3+:Al3+ = 10:1 to 1:8. Comparing with the partial least squares (PIS) model, the HLA method was simple, accuracy and precise.

An unusual electrochemically induced demetalation of iron-substituted Keggin-type undecatungstozincate ZnW11FeIII(H2O)O-39(7-)

Firstly reported for Fe-containing transition metal substituted polyoxometalates was an unusual Fe-centered demetalation process induced by the reduction of ZnW11FeIII to ZnW11FeII which resulted in a new couple of Fe-relating redox waves at positive potentials. (C) 1999 Elsevier Science S.A. All rights reserved.

NMR relaxation studies of GdDTPA in human serum albumin solution

The water relaxation enhancement behavior of GdDTPA in human serum albumin (HSA) solution has been studied. The results indicate that GdDTPA can integrate noncovalently with HSA, mainly in forms of (GdDTPA)HSA and (GdDTPA),HSA, for which the apparent equilibrium constants are 0.05 mM(-1) and 0.02 mM(-2), respectively. (C) 1999 Elsevier Science Ltd. All rights reserved.

Study of (TPP)H-2 vapor deposited film on iron

The film by tetraphenylporphyrin((TPP)H-2) vapor deposition on iron was investigated by means of XPS, SEM and visible spectroscopy. N(1s) binding energy characteristic of(TPP)H-2 was gained directly from the deposited samples. N(1s) binding energy of the surface was greatly changed after the deposited sample was washed with solvent. It is indicated that the deposited film is composed of an outer-layer of physically adsorbed (TPP)H-2, and an inner-layer of chemically modified (TPP)H-2.

NMR studies of Gd(DTPA-BIN) in human serum albumin solution

Stable gadolinium complexes, such as Gd(DTPA) and Gd(DOTA), are usually used as the contrast agents for magnetic resonance imaging(MRI). Reported here are the enhanced relaxation properties of a novel gadolinium complex, diethylene-triaminopentaacetate Lis (isoniazid) [Gd(DTPA-BIN)], in aqueous and in human serum albumin(HSA) solution, which indicates that (1) two Gd(DTPA-BIN) can integrate non-covalently with one HSA with an equilibrium constant of 0. 02 mmol(-2) . L-2 ; (2) the relaxivities are 3. 28 and 4. 92 mmol(-1) . L . s(-1) for the free Gd(DTPA-BIN) and the [Gd(DTPA-BIN)](2), HSA conjugator, respectively; (3) the rotational correlation time of protein conjugator is notably higher than that of the free complex, The above results may imply that Gd(DTPA-BIN) has a higher tissue selectivity than that of its parent Gd(DTPA).

Rapid automated in-situ monitoring of total dissolved iron and total dissolved manganese in underground water by reverse-flow injection with chemiluminescence detection during the process of water treatment

Measurement of iron and manganese is very important in evaluating the quality of natural waters. We have constructed an automated Fe(II), total dissolved iron(TDI), Mn(II), and total dissolved manganese(TDM) analysis system for the quality control of underground drinking water by reverse flow injection analysis and chemiluminescence detection(rFIA-CL), The method is based on the measurement of the metal-catalyzed light emission from luminol oxidation by potassium periodate. The typical signal is a narrow peak, in which the height is proportional to light emitted and hence to the concentration of metal ions. The detection limits were 3 x 10(-6) mu g ml(-1) for Fe(II) and the linear range extents up to 1.0 x 10(-4) and 5 x 10(-6) mu g ml(-1) for Mn(II) cover a linear range to 1.0 x 10(-4) mu g ml(-1). This method was used for automated in-situ monitoring of total dissolved iron and total dissolved in underground water during water treatment. (C) 1997 Elsevier Science B.V.