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The kinetics of oxidation of l-asparagine by bis(hydrogenperiodato)argentate(III) complex anion ([Ag(HIO6)2]5−) has been studied in the temperature range of 10.0–25.0 °C in aqueous alkaline media. An overall second-order character is observed, the reaction being first order with respect to both Ag(III) and Asn. The observed second-order rate constants $$ k^{{\prime }} $$ are increased when [OH−] is increased, but are decreased with increasing total concentration of periodate, [IO 4 − ]tot. The oxidation results in both decarboxylation and deamination of Asn. A reaction mechanism is proposed which involves two pre-equilibria leading to an intermediate complex [Ag(HIO6)(Asn)(OH)]3−. This is followed by the collapse of the intermediate in two parallel reaction paths as the rate-determining steps; one path is independent of OH−, while the other involves OH−. The rate equation has been derived from the reaction mechanism, and the equilibrium constants and rate parameters have been evaluated. The mode of electron transfer is discussed. The reaction mechanism and electron transfer mode in the present system have no similarities to those derived for the oxidations of Asn by other oxidants reported previously, underlining the diverse nature of Asn oxidations.

A new method is proposed to obtain the dynamic responses of the vehicle–track coupling system under the conditions of rail thermal stress changes in high-speed railways. Exact models are established with different rail longitudinal forces, in which multibody dynamic models are used for vehicles and the direct stiffness method for structures. In order to provide a general, simple and flexible formulation to express longitudinal stress distribution, the accurate model of long slab track consists of many small units with parameters which can be initialised separately. The exact analytical equation of track frequency and modal function was obtained by the transition matrix method, which can be used in calculating the dynamic response of wheel–rail coupling model. The proposed model is verified through comparisons with other classical solutions. Under the influence of train velocities and track irregularities, the specific vibration performances that frequency shifted and amplitude peak enhanced with thermal f...

The presence of sulfonamide (SA) residues in foods is largely due to the raising of animals with sulfonamide antibiotics added or polluted feedstuff. In this paper, a sensitive method was developed for the determination of the residues of three sulfonamides in animal-derived food; the SAs include sulfadimidine (SDD), sulfadiazine (SDZ), and sulfathiazole (STZ). The method is based on capillary zone electrophoresis (CE) with online chemiluminescence (CL) detection, using an Ag(III) complex as an oxidant. These SAs have an inhibiting effect on the Ag(III)-luminol CL reaction. The electrophoretic buffer is 12.0 mM sodium borate. Under a set of optimized conditions, the linear ranges for the detections were found to be 10.0-200 µg·mL-1 for SDD and SDZ, and 2.0-50.0 µg·mL-1 for STZ. The detection limits were 2.75, 3.14, and 0.65 µg·mL-1 for SDD, SDZ, and STZ, respectively. Relative standard deviations (RSD) for the peak heights were between 2.1% and 2.8% (n = 7). The proposed method was used in the analysis of the SAs in samples from pork meat, chicken meat, and milk, showing satisfactory detection results. A reaction mechanism was also proposed for the Ag(III)-luminol-SA CL reactions. The method has potential applications for the monitoring of residue levels of the three SAs in food, providing food safety data.

Amblyopia results from inadequate visual experience during the critical period of visual development. Abnormal binocular interactions are believed to play a critical role in amblyopia. These binocular deficits can often be resolved, owing to the residual visual plasticity in amblyopes. In this study, we quantitatively measured the sensory eye dominance in treated anisometropic amblyopes to determine whether they had fully recovered. Fourteen treated anisometropic amblyopes with normal or corrected to normal visual acuity participated, and their sensory eye dominance was assessed by using a binocular phase combination paradigm. We found that the two eyes were unequal in binocular combination in most (11 out of 14) of our treated anisometropic amblyopes, but none of the controls. We concluded that the treated anisometropic amblyopes, even those with a normal range of visual acuity, exhibited abnormal binocular processing. Our results thus suggest that there is potential for improvement in treated anisometropic amblyopes that may further enhance their binocular visual functioning.

This paper proposes a rail defect location method based on a single mode extraction algorithm (SMEA) of ultrasonic guided waves. Simulation analysis and verification were conducted. The dispersion curves of a CHN60 rail were obtained using the semi-analytical finite element method, and the modal data of the guided waves were determined. According to the inverse transformation of the excitation response algorithm, modal identification under low-frequency and high-frequency excitation was realized, and the vibration displacements at other positions of a rail were successfully predicted. Furthermore, an SMEA for guided waves is proposed, through which the single extraction results of four modes were successfully obtained when the rail was excited along different excitation directions at a frequency of 200 Hz. In addition, the SMEA was applied to defect location detection, and the single reflection mode waveform of the defect was extracted. Based on the group velocity of the mode and its propagation time, the distance between the defect and the excitation point was measured, and the defect location was predicted as a result. Moreover, the SMEA was applied to locate the railhead defect. The detection mode, the frequency, and the excitation method Were selected through the dispersion curves and modal identification results, and a series of signals of the sampling nodes were obtained using the three-dimensional finite element software ANSYS. The distance between the defect and the excitation point was calculated using the SMEA result. When compared with the structure of the simulated model, the errors obtained were all less than 0.5 m, proving the efficacy of this method in precisely locating rail defects, thus providing an innovated solution for rail defect location.

Biomedical research often requires primary cultures of specific cell types, which are challenging to obtain at high purity in a reproducible manner. Here we engineered the murine Rosa26 locus by introducing the diphtheria toxin receptor flanked by loxP sites. The resultant strain was nicknamed the Terminator mouse. This approach results in diphtheria toxin–receptor expression in all non-Cre expressing cell types, making these cells susceptible to diphtheria toxin exposure. In primary cultures of kidney cells derived from the Terminator mouse, over 99.99% of cells were dead within 72h of diphtheria toxin treatment. After crossing the Terminator with the podocin-Cre (podocyte specific) mouse or the Ggt-Cre (proximal tubule specific) mouse, diphtheria toxin treatment killed non-Cre expressing cells but spared podocytes and proximal tubule cells, respectively, enriching the primary cultures to over 99% purity, based on both western blotting and immunostaining of marker proteins. Thus, the Terminator mouse can be a useful tool to selectively and reproducibly obtain even low-abundant cell types at high quantity and purity.

Developing and adult ureters express the epigenetic regulator Brg1, but the role of Brg1 in ureter development is not well understood. We conditionally ablated Brg1 in the developing ureter using Hoxb7-Cre and found that Brg1 expression is upstream of p63, Pparγ, and sonic hedgehog (Shh) expression in the ureteral epithelium. In addition, epithelial stratification in the basal cells required Brg1-dependent p63 expression, whereas terminal differentiation of the umbrella cells required Brg1-dependent Pparγ expression. Furthermore, the loss of ureteric Brg1 resulted in failure of Shh expression, which correlated with reduced smooth muscle cell development and hydroureter. Taken together, we conclude that Brg1 expression unifies three aspects of ureter development: maintenance of the basal cell population, guidance for terminal differentiation of urothelial cells, and proper investment of ureteral smooth muscle cells.

To study differentially expressed proteins on water-holding capacity (WHC) during postmortem aging of longissimus lumborum muscle, samples were classified according to drip loss into high and low drip loss groups. Fifty-five proteins were differentially abundant at days 0, 1 and 7 during postmortem aging and identified by MALDI TOF/TOF. The identified proteins can be divided into four main categories: metabolic enzymes, cell structural proteins, stress related proteins and transport proteins. Myosin light chain, heat shock protein 27 and triosephosphate isomerase showed a major difference between the two groups and may have the potential to be biological markers for WHC prediction. Furthermore, bioinformatics analysis revealed that the identified proteins were related to carbon metabolism, glycolysis and biosynthesis of amino acids and pyruvate metabolism. The functions of the identified proteins contribute to a more detailed molecular view of the processes behind WHC and are a valuable resource for future investigations.

The kinetics of oxidation of pyrrolidine by bis(hydrogenperiodato)argentate(III) complex anion ([Ag(HIO6)2]5−) was studied in alkaline medium, with reaction temperatures in the range of 15.0–30.0 °C. The experiments indicated that the oxidation follows an overall second-order reaction, being first-order in both Ag(III) and pyrrolidine. The observed second-order rate constants, k′, decreased with increasing [IO4 −] but increased slightly with increasing [OH−]. The influence of ionic strength on the reaction rate was also investigated. The oxidation resulted in oxidative deamination of pyrrolidine, giving 4-hydroxybutyrate as the product. A reaction mechanism is proposed which includes an equilibrium between [Ag(HIO6)2]5− and [Ag(HIO6)2(OH)(H2O)]2−; these two Ag(III) species are reduced by pyrrolidine in parallel rate-determining steps. The rate equation derived from the proposed mechanism can explain the experimental observations. The rate constants of the rate-determining steps, together with the associated activation parameters, were calculated accordingly.

A sensitive simple method is presented for the determination of three major catecholamines in human urine by capillary electrophoresis (CE) with on-line chemiluminescence (CL) detection. This was also the first time that the luminol-Ag(III) complex CL system was used for CE detection. This method was based on the enhancing effect of epinephrine (EP), norepinephrine (NE), and dopamine (DA) on the CL reaction between luminol and the Ag(III) complex in alkaline solution. The separations and determinations were performed with an electrophoretic buffer consisting of 20.0mM sodium borate and 1.0mM luminol. Under optimized conditions, the three catecholamines were baseline separated and detected in less than 8 min. Detection limits of 7.9 × 10(-8)M, 1.0 × 10(-7)M, and 6.9 × 10(-8)M were observed for EP, NE, and DA, respectively. Relative standard deviation (RSD) values for the peak height were 4.7% to 5.4% (n = 5). Our proposed method was applied to the determinations of the catecholamines in urine samples from 12 healthy individuals and 26 pheochromocytoma patients. Our results suggest that this method might be useful to monitor the catecholamine levels in routine screening and to diagnose pheochromocytoma.

Renal tubular atrophy accompanies many proteinuric renal diseases, suggesting that glomerular proteinuria injures the tubules. However, local or systemic inflammation and filtration of abnormal proteins known to directly injure tubules are also present in many of these diseases and animal models; therefore, whether glomerular proteinuria directly causes tubular injury is unknown. Here, we examined the renal response to proteinuria induced by selective podocyte loss. We generated mice that express the diphtheria toxin receptor exclusively in podocytes, allowing reproducible dose-dependent, specific ablation of podocytes by administering diphtheria toxin. Ablation of 40% of podocytes led to progressive glomerulosclerosis, profound tubular injury, and renal failure. These data suggest that glomerular proteinuria in the absence of severe structural glomerular injury activates tubular proliferation, potentially as an adaptive response to minimize the loss of filtered proteins.

A novel sensitive chemiluminescence (CL) system ([Ag(HIO6)2]5--luminol reaction system), coupled with a flow injection, is introduced for determination of d-penicillamine. The system is based on the enhancement effect of chemiluminescence reaction by penicillamine in alkaline medium. Under the optimum conditions, the CL intensity is proportional to the concentrations of d-penicillamine with a good linearity. The linear range covers 1.5-150 ng mL-1 and the limit of detection of the method is 0.8 ng mL-1. The relative standard deviation is 0.23% for 11 repeated measurements of 0.06 µg mL-1 d-penicillamine. The method has been successfully applied to the determinations of d-penicillamine in pharmaceutical preparations and urine samples, giving rise to satisfactory results. Based on the chemiluminescent spectra and free radical trapping experiment performed in this work, a possible reaction mechanism for this reaction system is suggested. Um novo sistema de quimioluminescência (CL), sensível, (reação [Ag(HIO6)2]5--luminol), acoplado com injeção em fluxo, é introduzido para determinação de d-penicilamina. O sistema é baseado no efeito do aumento da reação de quimioluminescência por penicilamina em meio alcalino. Sob condições ótimas, a intensidade de CL é proporcional às concentrações de d-penicilamina com uma boa linearidade. O intervalo linear é de 1,5-150 ng mL-1 e o limite de detecção do método, 0,8 ng mL-1. O desvio padrão relativo é 0,23% para 11 repetições de 0,06 µg mL-1 de d-penicilamina. O método tem sido aplicado com sucesso às determinações de d-penicilamina em preparações farmacêuticas e amostras de urina, proporcionando resultados satisfatórios. Com base nos espectros de quimioluminescência e no experimento de aprisionamento de radicais livres realizado neste trabalho, um possível mecanismo de reação para esse sistema reacional é sugerido.

The oxidation of N,N-dimethylethanolamine (DMEA) by bis(hydrogenperiodato) argentate(III) ([Ag(HIO6)2]5−) was studied in aqueous alkaline medium. Formaldehyde and dimethylamine were identified as the major oxidation products after the oxidation of DMEA. The oxidation kinetics was followed spectrophotometrically in the temperature range of 25.0 °C–40.0 °C. It was found that the reaction was first order in [Ag(III)]; the oberved first-order rate constants kobsd as functions of [DMEA], [OH−] and total concentration of periodate (\([\mathrm{IO}_{4}^{-}]_{\mathrm{tot}}\)) were analyzed and were revealed to follow a rate expression: \(k_{\mathrm{obsd}} = (k_{1} +k_{2}[\mathrm{OH}^{-}])K_{1}K_{2}[\mathrm{DMEA}]/\{f([\mathrm{OH}^{-}])[\mathrm{IO}_{4}^{-}]_{\mathrm{tot}}+ K_{1} + K_{1}K_{2}[\mathrm{DMEA}]\}\). Rate constants k1 and k2 and equilibrium constant K2 were derived; activation parameters corresponding to k1 and k2 were computed. In the proposed reaction mechanism, a peridato-Ag(III)-DMEA ternary complex is formed indirectly through a reactive intermediate species [Ag(HIO6)(OH)(H2O)]2−. In subsequent rate-determining steps as described by k1 and k2, the ternary complex decays to Ag(I) through two reaction pathways: one of which is spontaneous and the other is prompted by an OH−.

A novel flow injection analysis-direct chemiluminescence (FI-CL) method has been developed for determination of trace amounts of dopamine (DA) based on the enhancing effect of DA on the CL reaction of luminol with an Ag(III) complex in alkaline solution. Under optimum conditions, CL intensities are proportional to the concentration of DA in the range of 1.0 × 10−10 to 4.0 × 10−8 mol L−1. The detection limit is 3.0 × 10−11 mol L−1 for DA (3s), with a relative standard deviation (n = 13) of 2.3% for 1.0 × 10−8 mol L−1 DA. This method has also been applied for the determination of DA in commercial pharmaceutical injection samples. On the basis of the CL spectra and the results of the free-radical trapping experiment of this work, a reaction mechanism for this CL reaction is proposed and discussed. Copyright © 2010 John Wiley & Sons, Ltd.

Oxidation of N-methylethylamine by bis(hydrogenperiodato)argentate(III) ([Ag(HIO6)2]5−) in alkaline medium results in demethylation, giving rise to formaldehyde and ethylamine as the oxidation products. The oxidation kinetics has been followed spectrophotometrically in the temperature range of 20.0–35.0 °C, and shows an overall second-order character: being first-order with respect to both Ag(III) and N-methylethylamine. The observed second-order rate constants k′ increase with increasing [OH−] of the reaction medium, but decrease with increasing the total concentration of periodate. An empirical rate expression for k′ has been derived as: k′ = (k a + k b[OH−])K 1/{f([OH−])[IO4 −]tot + K 1}, where k a and k b are rate parameters, and K 1 is an equilibrium constant. These parameters have been evaluated at all the temperatures studied, enabling calculation of activation parameters. A reaction mechanism is suggested to involve two pre-equilibria, leading to formation of an intermediate Ag(III) complex, namely [Ag(HIO6)(OH)(MeNHEt)]2−. In the subsequent rate-determining steps, this intermediate undergoes inner-sphere electron transfer from the coordinated amine to the metal center via two distinct routes, one of which is spontaneous while the other is mediated by a hydroxide ion.

Kinetics of oxidation of dl-pipecolinate by bis(hydrogenperiodato)argentate(III) complex anion, [Ag(HIO6)2]5−, has been studied in aqueous alkaline medium in the temperature range of 25–40 °C. The oxidation kinetics is first order in the silver(III) and pipecolinate concentrations. The observed second-order rate constant, decreasing with increasing [periodate] is virtually independent of [OH−]. α-Aminoadipate as the major oxidation product of pipecolinate has been identified by chromatographic analysis. A reaction mechanism is proposed that involves a pre-equilibrium between [Ag(HIO6)2]5− and [Ag(HIO6)(H2O)(OH)]2−, a mono-periodate coordinated silver(III) complex. Both Ag(III) complexes are reduced in parallel by pipecolinate in rate-determining steps (described by k 1 for the former Ag(III) species and k 2 for the latter). The determined rate constants and their associated activation parameters are k 1 (25 °C) = 0.40 ± 0.02 M−1 s−1, ∆H 1 ≠ = 53 ± 2 kJ mol−1, ∆S 1 ≠ = −74 ± 5 J K−1 mol−1 and k 2 (25 °C) = 0.64 ± 0.02 M−1 s−1, ∆H 2 ≠ = 41 ± 2 kJ mol−1, ∆S 2 ≠ = −110 ± 5 J K−1 mol−1. The time-resolved spectra, a positive dependence of the rate constants on ionic strength of the reaction medium, and the consistency of pre-equilibrium constants derived from different reaction systems support the proposed reaction mechanism.

A new Ag(III) complex-luminol chemiluminescent system which was applied to the determination of epinephrine is firstly reported. Based on the enhancing effect of epinephrine on the chemiluminescence reaction of luminol with [Ag(HIO6)2]5− in alkaline solution, a highly sensitive chemiluminescence (CL) detection by flow injection analysis (FIA) was developed for epinephrine. Under the optimum conditions, CL intensity was proportional to concentration of epinephrine in the 1.0×10−9–1.0×10−7 mol·L−1 range. The limit of detection was 8.0×10−10 mol·L−1 for epinephrine (3δ), with a relative standard deviation (n=11) of 2.9% for 1.5×10−8 mol·L−1 epinephrine. The method validation was done with epinephrine determinations in commercial pharmaceutical products. The mechanism of the reactions was also discussed.

Oxidation of α-diols, namely ethylene glycol, 1,2-propanediol, and 1,2-butanediol, by [Ag(HIO6)2]5− is kinetically first-order with respect to the Ag(III) complex. The dependence of observed first-order rate constants k obs on [α-diol] can generally be expressed by: k obs = k x[α-diol] + k y[α-diol]2. Our experimental results demonstrate that the different rate laws derived in the oxidation reactions of ethylene glycol (J. H. Shan et al. Chin. J. Chem. 24:478, 2006) and 1,2-butanediol (J. H. Shan et al. Transition Met. Chem. 30:651, 2005) by the Ag(III) complex are probably not correct. In turn, the reaction mechanisms based on these rate laws should probably be treated with caution.

Oxidation of 3-(4-methoxyphenoxy)-1,2-propanediol (MPPD) by bis(hydrogenperiodato) argentate(III) complex anion, [Ag(HIO6)2]5− has been studied in aqueous alkaline medium by use of conventional spectrophotometry. The major oxidation product of MPPD has been identified as 3-(4-methoxyphenoxy)-2-ketone-1-propanol by mass spectrometry. The reaction shows overall second-order kinetics, being first-order in both [Ag(III)] and [MPPD]. The effects of [OH−] and periodate concentration on the observed second-order rate constants k′ have been analyzed, and accordingly an empirical expression has been deduced: $$ {{k^{\prime} = \left( {k_{\text{a}} + k_{\text{b}} \left[ {{\text{OH}}^{ - } } \right]} \right)K_{ 1} } \mathord{\left/ {\vphantom {{k^{\prime} = \left( {k_{\text{a}} + k_{\text{b}} \left[ {{\text{OH}}^{ - } } \right]} \right)K_{ 1} } {\left\{ {{\text{f}}\left( {\left[ {{\text{OH}}^{ - } } \right]} \right)\left[ {{\text{IO}}_{ 4}^{ - } } \right]_{\text{tot}} + K_{ 1} } \right\}}}} \right. \kern-\nulldelimiterspace} {\left\{ {{\text{f}}\left( {\left[ {{\text{OH}}^{ - } } \right]} \right)\left[ {{\text{IO}}_{ 4}^{ - } } \right]_{\text{tot}}\, +\, K_{ 1} } \right\}}}, $$ where [IO4 −]tot denotes the total concentration of periodate and k a = (0.19 ± 0.04) M−1 s−1, k b = (10.5 ± 0.3) M−2 s−1, and K 1 = (5.0 ± 0.8) × 10−4 M at 25.0 °C and ionic strength of 0.30 M. Activation parameters associated with k a and k b have been calculated. A mechanism is proposed, involving two pre-equilibria, leading to formation of a periodato–Ag(III)–MPPD complex. In the subsequent rate-determining steps, this complex undergoes inner-sphere electron-transfer from the coordinated MPPD molecule to the metal center by two paths: one path is independent of OH−, while the other is facilitated by a hydroxide ion.

Oxidation of L-proline by bis(hydrogen periodato)argentate(III) complex anion, [Ag(HIO6)2]5−, has been studied in aqueous alkaline medium in the temperature range of 25–40 °C by use of conventional spectrophotometry. Under the conditions for kinetic measurements, the oxidation results in decarboxylation of proline, giving rise to γ-aminobutyrate as identified by mass spectrometry. The oxidation kinetics is first order with respect to the silver(III) and proline concentrations; the second-order rate constants, decreasing with increasing [periodate], are essentially independent of [OH−]. The kinetic results were interpreted in terms of a reaction mechanism which involves a pre-equilibrium between [Ag(HIO6)2]5− and [Ag(HIO6)(H2O)(OH)]2−, a mono-periodate coordinated silver(III) complex. Both Ag(III) complexes are reduced parallelly by the fully deprotonated form of proline in rate-determining steps (described by k1 for the former Ag(III) and k2 for the latter one). The determined rate constants and their associated activation parameters are k1(25 °C) = (1.87±0.04) L·mol−1·s−1, ΔH1≠= (45±4) kJ· mol−1, ΔS1≠= (−90±13) J·K−1·mol−1 and k2(25 °C) = (3.2±0.5) L·mol−1·s−1, ΔH2≠= (34±2) kJ·mol−1, ΔS2≠= (−122±10) J·K−1·mol−1. This is also the first time to find that [Ag(HIO6)2]5− is also reactive toward a particular reductant and shows a lower reactivity than [Ag(HIO6)(OH)(H2O)]2−.

This study was designed to determine whether the supplement of energy compound could attenuate strain-induced damage to skeletal muscle in rats. Energy compound is a saline mixture of the following ingredients: ATP (10 mg), Coenzyme-A (50 units), Coenzyme-Q10 (50 mg), Cytochrome C (30 mg) and Vitamin B6 (50 mg). Experimental animals were injured in right gastrocnemius muscles by a strain injury model. Energy compound groups were given energy compound 10 ml/kg body weight per day since injured, while saline groups were given saline at the same dose. And a sham operation was performed on the right hindlimb of control group. Plasma was centrifuged to measure lactate dehydrogenase (LDH), lactic acid (La) and creatine kinase (CK) on 3, 7 and 14 d post injury. Muscles were removed and fixed for histology obser- vation and immunohistochemistry assay of desmin and vimentin. The results showed a similar tendency of plasma CK, La and LDH in saline and energy compound groups, while the lower level was found in the energy-compound group. The histological examination of muscle sections revealed a lower degree of damage in the energy compound group in which the expression levels of desmin and vimentin were higher than in the saline group. It is suggested that energy com- pound supplement may attenuate strain-induced muscle damage and facilitate its regeneration.

The kinetics of oxidation of phenyldiethanolamine (PEA) by a silver(III) complex anion, [Ag(HIO6)2]5−, has been studied in an aqueous alkaline medium by conventional spectrophotometry. The main oxidation product of PEA has been identified as formaldehyde. In the temperature range 20.0–40.0 °C , through analyzing influences of [OH−] and [IO4−]tot on the reaction, it is pseudo-first-order in Ag(III) disappearance with a rate expression: kobsd = (k1 + k2[OH−]) K1K2[PEA]/{f([OH−])[IO4−]tot + K1 + K1K2 [PEA]}, where k1 = (0.61 ± 0.02) × 10−2 s−1, k2 = (0.049 ± 0.002) M−1 s−1 at 25.0 °C and ionic strength of 0.30 M. Activation parameters associated with k1 and k2 have also been derived. A reaction mechanism is proposed involving two pre-equilibria, leading to formation of an Ag(III)-periodato-PEA ternary complex. The ternary complex undergoes a two-electron transfer from the coordination PEA to the metal center via two parallel pathways: one pathway is spontaneous and the other is assisted by a hydroxide ion.

Oxidation of l-serine and l-threonine by a silver(III) complex anion, [Ag(HIO(6))(2)](5-), has been studied in aqueous alkaline medium. The oxidation products of the amino acids have been identified as ammonia, glyoxylic acid and aldehyde (formaldehyde for serine and acetaldehyde for threonine). Kinetics of the oxidation reactions has been followed by the conventional spectrophotometry in the temperature range of 20.0-35.0 degrees C and the reactions display an overall second-order behavior: first-order with respect to both Ag(III) and the amino acids. Analysis of influences of [OH(-)] and [periodate] on the second-order rate constants k' reveals an empirical rate expression: k(')=(k(a)+k(b)[OH(-)])K(1)/([H(2)IO(6)(3-)](e)+K(1)), where [H(2)IO(6)(3-)](e) is equilibrium concentration of periodate, and where k(a)=6.1+/-0.5M(-1)s(-1), k(b)=264+/-6M(-2)s(-1), and K(1)=(6.5+/-1.3)x10(-4)M for serine and k(a)=12.6+/-1.7M(-1)s(-1), k(b)=(5.5+/-0.2)x10(2)M(-2)s(-1), and K(1)=(6.2+/-1.5)x10(-4)M for threonine at 25.0 degrees C and ionic strength of 0.30M. Activation parameters associated with k(a) and k(b) have also been derived. A reaction mechanism is proposed to involve two pre-equilibria, leading to formation of an Ag(III)-periodato-amino acid ternary complex. The ternary complex undergoes a two-electron transfer from the coordinated amino acid to the metal center via two parallel pathways: one pathway is spontaneous and the other is assisted by a hydroxide ion. Potential applications of the Ag(III) complex as a reagent for modifications of peptides and proteins are implicated.

Mephenesin is being used as a central-acting skeletal muscle relaxant. Oxidation of mephenesin by bis(hydrogenperiodato)argentate(III) complex anion, [Ag(HIO6)2]5−, has been studied in aqueous alkaline medium. The major oxidation product of mephenesin has been identified as 3-(2-methylphenoxy)-2-ketone-1-propanol by mass spectrometry. An overall second-order kinetics has been observed with first order in [Ag(III)] and [mephenesin]. The effects of [OH−] and periodate concentration on the observed second-order rate constants k′ have been analyzed, and accordingly an empirical expression has been deduced: k′ = (ka + kb[OH−])K1/{f([OH−])[IO−4]tot + K1}, where [IO−4]tot denotes the total concentration of periodate, ka = (1.35 ± 0.14) × 10−2M−1s−1 and kb = 1.06 ± 0.01 M−2s−1 at 25.0°C, and ionic strength 0.30 M. Activation parameters associated with ka and kb have been calculated. A mechanism has been proposed to involve two pre-equilibria, leading to formation of a periodato-Ag(III)-mephenesin complex. In the subsequent rate-determining steps, this complex undergoes inner-sphere electron transfer from the coordinated drug to the metal center by two paths: one path is independent of OH− whereas the other is facilitated by a hydroxide ion. In the appendix, detailed discussion on the structure of the Ag(III) complex, reactive species, as well as pre-equilibrium regarding the oxidant is provided. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 39: 440–446, 2007

By HG-AFS, a new method was proposed for simultaneous determination of total arsenic and total selenium existed in the Chinese medicinal herbs in tartaric acid medium. The effects of analytical conditions and coexisting ions on the fluorescence signal intensity of analytes were investigated. The proposed method was provided with linear response ranges above 22 μg l−1 for As and 44 μg l−1 for Se, and the detection limits of 0.13 and 0.12 μg l−1 were obtained for As and Se respectively. The recoveries of 93.8–96.1% for As and 95.3–99.1% for Se, and the precision of 1.2–3.8% and 2.4–5.3% (R.S.D., n = 8) respectively, were obtained via simultaneous determined four samples of Chinese medicinal herbs and three certified botanic reference materials successfully. The proposed method has the advantages of simple operation, high sensitivity and high efficiency.

A new method is proposed for simultaneous determination of traces of arsenic (As) and selenium (Se) in biological samples by hydride-generation double-channel non-dispersive atomic-fluorescence spectrometry (HG-AFS) from tartaric acid media. The effects of analytical conditions on fluorescence signal intensity were investigated and optimized. Interferences from coexisting ions were evaluated. Under optimum conditions linear response ranges above 20 microg L(-1) for As and 32 microg L(-1) for Se were obtained with detection limits of 0.13 and 0.12 microg L(-1), respectively. The precision for eleven-fold determination of As at the 4 microg L(-1) level and of Se at the 8 microg L(-1) level were 2.7 and 1.9% (RSD), respectively. Recoveries of 92.5-95.5% for As and 101.2-108.4% for Se were obtained for four biological samples and two certified biological reference materials. The proposed method has the advantages of simple operation, high sensitivity, and high efficiency; it was successfully used for simultaneous determination of As and Se in biological samples.

On account of the difficulty in measuring the true rail thermal stress, a new method is proposed to rapidly evaluate rail thermal stress based on the dynamic responses of vehicle-track coupling system. A vertical slab-track model with the rail longitudinal thermal stress is established. The natural vibration characteristic of the track under the influences of the rail longitudinal stress distribution has been calculated individually. The changed vibration modal function and frequency of track are used in calculating the dynamic response of vehicle-track coupling model. It can be seen from the dynamic responses that vibration frequency is shifted and amplitude peak is enhanced by thermal stress. In this paper, the digital features are extracted from the responses of wheelset and rail in time and frequent domain, which are used as training samples in support vector machine (SVM). Then, the rail longitudinal stress can be estimated with the prediction model. The numerical simulation results indicate that, by utilizing the train as the excitation source of the dynamic system, the rail longitudinal stress can be estimated with measurable response of wheel and rail at an acceptable accuracy.

A simple and sensitive method based on flow-injection chemiluminescence analysis coupled with luminol-Ag(III) complex was developed for the determination of uric acid (UA) in human urine. The method was based on the chemiluminescence (CL) reaction of luminol with Ag(III) in alkaline solution. UA in the urine can dramatically enhance CL intensities. In optimum conditions, the relative CL intensity had a linear relationship with UA concentration in the range of 1.0 × 10-8 to 5.0 × 10-6 mol L-1 with a detection limit of 2.0 × 10-9 mol L-1 (3σ). The relative standard deviation (n = 11) was 0.71% for 1.0 × 10-7 mol L-1 UA. Possible reaction mechanisms for the CL system were suggested based on the UV absorption spectra, CL spectra, and the free radical trapping experiment performed in this work. Um método simples e sensível baseado na análise de quimiluminescência por injeção em fluxo acoplado ao complexo luminol-Ag(III) foi desenvolvido para se determinar ácido úrico (UA) em urina humana. O método se baseia na reação de quimiluminescência (CL) do luminol com Ag(III) em solução alcalina, sendo que o UA da urina aumenta dramaticamente as intensidades CL. Em condições ótimas, a intensidade CL relativa aumentava linearmente com a concentração de UA, na faixa de 1.0 × 10-8 a 5.0 × 10-6 mol L-1 com um limite de detecção de 2.0 × 10-9 mol L-1 (3σ). O desvio padrão relativo (n = 11) era de 0.71% para 1.0 × 10-7 mol L-1 UA. Os mecanismos de reação possíveis do sistema CL foram sugeridos com base nos espectros de absorção UV, espectros CL e no experimento de trapping de radicais livres feitos neste trabalho.

The accelerated growth of the past 30 years has advanced the entrepreneurial sector in China. The surge in private wealth management services (PWM) has resulted in enhancing this segment‟s profile globally. The ensuing tension between demand and lagging development may force change to markets and regulations. It is therefore to be expected that the financial service providers (FSPs) will be prompted to follow suit. This essay seeks to analyze how FSPs and PWM firms will meet the demands of the private and public sectors alike. Furthermore,this essay seeks to provide insights that may benefit interested par

This paper proposes a method which describes the information precision with a soft fusion model, instead of the traditional rigid fusion method. The method is divided into two steps, the pretreatment model and fusion center model. Each forms a relative independent model, and the two models have a progressive relationship. The former is used for consistency evaluation, data cleaning and invalid data eliminating, while the latter provides fusion results and variable precision fusion expression by the adaptive threshold clustering algorithm. Experimental results show that the fusion method can not only give every SST data a different precision, but also carry more information to describe precision multiple distribution, which make users get high-quality data and enjoy more rights.

Now there are many researches on the assessment of sea surface temperature(SST) by remote-sensing at home and abroad, most of which focus on cross-validation of SST data and on-site measured data. For the non-measured waters, it's not easy to carry out assessment of SST, and now most of the assessment are an area average or macroscopic assessment based on the week, month, or specified period, these methods can't provide the assessment products with precision from point to point. This paper proposes a mutual assessment model based on SST data and other fusion data of remote sensing data. For multi-source remote sensing SST, this model could provide us with higher-quality data, including the measurement efficiency, data distribution and credibility and so on.

Jointless track is an essential part of high speed railway. But the damage such as the buckled rail and the broken rail occasionally happened. In this paper a system is designed for monitoring the status of jointless track based on analyzing the principle of FBG (Fiber Bragg Grating) sensors and the structure of double columns end thorns. The layout of the FBG sensors, including displacement sensors, strain sensors and temperature sensors, which are installed on the end thorns at K761 position on the up line from Suzhou East Station to Bengbu South Station and Huaihe River Bridge on the China high speed line Beijing-Shanghai, is described in detail. Also the remote monitoring system software is introduced in this paper. The results of field tests show that the correlation among temperature, strain and displacement is well and sensors are stable and reliable during a long term remote monitoring.

Track irregularity is the main excitation source of wheel-track interaction. Due to the difference of speed, axle load and suspension parameters between track inspection train and the operating trains, the data acquired from the inspection car cannot completely reflect the real status of track irregularity when the operating trains go through the rail. In this paper, an estimation method of track irregularity is proposed using genetic algorithm and Unscented Kalman Filtering. Firstly, a vehicle-track vertical coupling model is established, in which the high-speed vehicle is assumed as a rigid body with two layers of spring and damping system and the track is viewed as an elastic system with three layers. Then, the static track irregularity is estimated by genetic algorithm using the vibration data of vehicle and dynamic track irregularity which are acquired from the inspection car. And the dynamic responses of vehicle and track can be solved if the static track irregularity is known. So combining with vehicle track coupling model of different operating train, the potential dynamic track irregularity is solved by simulation, which the operating train could goes through. To get a better estimation result, Unscented Kalman Filtering (UKF) algorithm is employed to optimize the dynamic responses of rail using measurement data of vehicle vibration. The simulation results show that the estimated static track irregularity and the vibration responses of vehicle track system can go well with the true value. It can be realized to estimate the real rail status when different trains go through the rail by this method.Copyright © 2012 by ASME

Regular measurement of tunnel complete profile is important to the train operation safety. An onboard tunnel clearance measurement device is designed by integrating photogrammetry with linear laser scanning in this paper. The main principle of design is based on the triangulation method using lasers and cameras. Multiple high speed industrial cameras are used to shoot the laser strip profile with a resolution of 1024×1280 pixels per frame. In order to improve the processing performance of the system, Field Programmable Gate Array (FPGA) has been employed as hardware design platform which has a strong ability on dealing with a large amount of image data. The algorithm proposed in this paper is embedded in FPGA hardware completely to process image sequences of 300 frames per second. The overall scheme, FPGA hardware implementation and the results of validation are presented. The results of experiments illustrate a good performance of the proposed system and adaptable ability to the various common tunnel conditions.

The railway line clearance detection is an important guarantee for the security of rail traffic. This paper studies a line clearance detection device based on noncontact measurement. On base of the system solution introduction, this paper emphasized on description of the software features and the design of the management information system. Also, the exceeding point real time judgment algorithm is presented, and the related experiment is completed. As shown in the experiment, the collection of the complete profile data, the judgment of the exceeding point and the management function of the data can precisely and timely complete.

On the basis of analyzing the mathematic model of the permanent magnet synchronous motor (PMSM), a novel approach to PMSM servo system using fuzzy active disturbance rejection controller (ADRC) is presented in this paper, which can meet the needs of rejecting the disturbance and time-vibration of parameters for the AC servo system. Modeling and simulation of the servo system are done based on MATLAB/Simulink, and the parameters of the PID controller are automatically adjusted on line to correct the system by using fuzzy adaptive controller. Then a fully digital AC servo system is designed according to the result of simulation using TMS320F2812, which is a type of Digital signal Processor (DSP). According to the results of simulation and tests, the designed servo system controller based on the theory of fuzzy active disturbance rejection has strong robustness, and especially has better effect on restraining the overshoot.

A new chemiluminescence (CL) system based on the reaction of Ag(III) complex with luminol is, for the first time, reported in this work. Incorporated with a flow injection analyses (FIA), the new CL system has been applied for the determination of free cortisol in human sera. The system is based on the CL reaction of luminol with Ag(III) in alkaline solutions, while cortisol can dramatically enhance CL intensities. Under optimum conditions, CL intensities are proportional to concentration of cortisol in the range of 0.05–7.5 nM. The limit of detection is 2.0 × 10 −11 M (3σ), with a relative standard deviation ( n = 11) of 1.9% for 3.5 × 10 −9 M cortisol. Eight human blood serum samples were all handled by solid-phase extraction (SPE) clean-up and enrichment before detection. This detection system is highly sensitive and convenient and may find wide applications. Based on the chemiluminescent spectra, a possible reaction mechanism is also suggested.