[Determination of serum proteins by resonance light scattering method with lidocaine as a probe].

A new method for the determination of bovine serum albumin (BSA) and human serum albumin (HSA) was developed by using resonance light scattering (RLS) technique via an interaction of serum albumin with lidocaine and sodium dodecylbenzene sulphonate (SDBS). The RLS intensity of serum albumin was enhanced in the presence of lidocaine and SDBS. The influences of some experimental factors, including incubation time, addition sequence of reagents, pH values, foreign substances and the concentrations of lidocaine and SDBS, on the enhancement of the RLS intensity were investigated. Under the optimal conditions, the enhanced RLS intensities were proportional to the concentrations of serum albumin in the range of 1.0-45.0 mg x L(-1) for BSA and 0.5-30.0 mg x L(-1) for HSA. The method was successfully applied to the determination of real human serum samples, with the relative standard deviations of 4.9%-5.7% (n = 5) and standard addition recoveries of 90%-103%. The method only involves the use of conventional fluorescence spectrometer and chemical reagents. It is simple, easy to operate and sensitive with the limit of detection of 0.14 mg x L(-1). The fresh human serum samples can be directly analyzed without the need of any prior pretreatment. The method can be a good alternative of choice for the determination of BSA and HSA.

[Study on the interaction of tetrandrine and bovine serum albumin].

The interaction of tetrandrine with bovine serum albumin was studied by fluorescence spectra and ultra-violet spectra. The results showed that tetrandrine could quench the intrinsic fluorescence of BSA. Both static quenching and non-radiation energy transfer were the main reasons for the fluorescence quenching. The quenching constants K(sv) at different temperatures were determined using Stern-Volmer equation. The K(sv) were 1.26 x 10(4) L x mol(-1) (300 K), 1.17 x 10(4) L x mol(-1) (310 K) and 1.12 x 10(4) L x mol(-1) (320 K). According to the Forster theory of non-radiation energy transfer, the binding distances (r) were 3.24 nm (300 K), 3.31 nm (310 K) and 3.50 nm (320 K). The binding constants (KA) between tetrandrine and BSA (300 K: 1.52 x 10(5) L x mol(-1); 310 K: 2.03 x 10(5) L x mol(-1); 320 K: 2.89 x 10(5) L x mol(-1)) and thermodynamic parameters were also obtained. The thermodynamic parameters indicated that the interaction of tetrandrine and BSA was driven mainly by hydrophobic force. Results of synchronous fluorescence spectrum showed that the binding could cause conformational changes of BSA.

[Spectroscopic study on the interaction between resveratrol and human serum albumin].

The interaction between resveratrol and human serum albumin (HSA) was studied by using fluorescence quenching spectra, synchronous fluorescence spectra and ultra-violet spectra. The Stern-Volmer curve of the fluorescence quenching of HSA by resveratrol indicated that the quenching mechanism between resveratrol and HSA was mainly static quenching, with nonradiation energy transfer occurring within single molecule. The binding constants (KA) were 2.39 x 10(5) (25 degrees C), 1.25 x 10(5) (35 degrees C) and 1.10 x 10(5) (45 degrees C), respectively. According to the Forster theory of nonradiation energy transfer, the binding distances (r) were 3.02 nm (25 degrees C), 3.46 nm (35 degrees C) and 3.79 nm (45 degrees C), respectively. The thermodynamic parameters showed that the interaction between resveratrol and HSA was mainly driven by hydrophobic force. Synchronous spectrum was used to investigate the conformational change of HSA.

[Study on the interaction between daidzein and human serum albumin].

The binding reaction between daidzein and human serum albumin (HAS) was studied by fluorescence quenching spectra, synchronous fluorescence spectra and ultraviolet spectra. The results indicated that daidzein led to the quenching of the intrinsic fluorescence of HSA. The fluorescence quenching mechanism between daidzein and HSA was mainly static quenching, with non-radiation energy transfer occurring within single molecule. The binding constants (KA) between daidzein and HSA were 0.34 x 10(4) (23 degrees C), 1.10 X 10(4) (30 degrees C) and 4.36 x 10(4) (40 degrees C), respectively. According to the Forster theory of non- radiation energy transfer, the binding distances (r) were 1.50 nm (23 degrees C), 1.46 nm (30 degrees C) and 1.42 nm (40 degrees C), respectively. The thermodynamic parameters were calculated, which indicated that the hydrophobic force played major roles between daidzein and human serum albumin. The effect of daidzein on the conformation of HAS was investigated using synchronous spectrum.

[Study on the interaction of genistein and human serum albumin by spectroscopic method].

The interaction of genistein and human serum albumin (HSA) was investigated by fluorescence quenching spectra, synchronous fluorescence spectra and ultra-violet absorption spectra. The results showed that the quenching mechanism of the intrinsic fluorescence of HSA by genistein is due to the formation of genistein-HSA complex, resulting in a static quenching procedure. The binding constants (KA) were 1.00 x 10(6) (27 degrees C), 1.66 x 10(6) (37 degrees C) and 5.25 x 10(6) (47 degrees C), respectively. According to the Förster theory of non-radiation energy transfer, the binding distances (r) were 2.59 nm (27 degrees C), 2.65 nm (37 degrees C) and 2.90 nm (47 degrees C), respectively. The thermodynamic parameters showed that the binding power between genistein and HSA is mainly the electrostatic interaction Synchronous spectrum was used to investigate the conformational change of HSA.

[Study on the interaction of luteolin with human serum albumin by fluorescence quenching method].

The interaction between luteolin and human serum albumin (HSA) was studied by using fluorescence quenching spectra, synchronous fluorescence spectra and ultra-violet spectra. The results showed that luteolin had a strong ability to quench the fluorescence of HAS The Stern-Volmer curve of the fluorescence quenching of HSA by luteolin indicated that the mechanism behind the quenching between luteolin and HSA was a static quenching. According to the Forster theory of non-radiation energy transfer, the binding distances (r) and the binding constants (KA) were calculated. The thermodynamic parameters showed that the interaction between luteolin and HSA was driven mainly by hydrophobic force. Synchronous spectra were used to investigate the conformational changes of HSA.

Interaction of tetrandrine with human serum albumin: a fluorescence quenching study.

The interaction of tetrandrine with human serum albumin (HSA) was studied by measuring fluorescence quenching spectra, synchronous fluorescence spectra and ultra-violet spectra. The fluorescence quenching spectra of HSA in the presence of tetrandrine showed that tetrandrine quenched the fluorescence of HSA. The quenching constants of tetrandrine on HSA were determined using the Stern-Volmer equation. Static quenching and non-radiation energy transfer were the two main reasons leading to the fluorescence quenching of HSA by tetrandrine. According to the Förster theory of non-radiation energy transfer, the binding distances (r) and the binding constants (K(A)) were obtained. The thermodynamic parameters obtained in this study revealed that the interaction between tetrandrine and HSA was mainly driven by a hydrophobic force. The conformational changes of HSA were investigated by synchronous spectrum studies.

[Study on the interaction of Nimodipine and bovine serum albumin by fluorescence quenching method].

The interaction of Nimodipine and bovine serum albumin (BSA) was studied using fluorescence spectroscopy (FS) and ultraviolet spectroscopy (UV). The apparent binding constants (KA) between Nimodipine and BSA were 5.01 x 10(4) (26 degrees C) and 4.46 x 10(4) (36 degrees C), and the binding sites (n) were 1.08 +/- 0.01. According to the Förster theory of non-radiation energy transfer, the binding distances (r) were also obtained. The experimental results showed that Nimodipine could quench the inner fluorescence of BSA by forming the Nimodipine-BSA complex. It was found that both static quenching and non-radiation energy transfer led to the fluorescence quenching. The process of binding was a spontaneous molecular interaction in which entropy increased while Gibbs free energy decreased. The thermodynamic parameters indicated that the interaction of Nimodipoine and BSA was driven mainly by static electrical force.

[Study on the interaction between brucine and bovine serum albumin].

The interaction between brucine and bovine serum albumin (BSA) was investigated using fluorescence spectroscopy (FS) and ultraviolet spectroscopy (UV). The experimental results showed that the brucine quenches the inner fluorescence by forming a brucine-BSA complex. It was found that both static quenching and non-radiation energy transfer were the main reasons for the fluorescence quenching. The apparent binding constants (K(A)) between brucine and BSA were 6. 3 x 10(3) (27 degrees C) and 7.7 x 10(3) (37 degrees C), and the binding sites (n) were 0.94 (27 degrees C) and 0.97 (37 degrees C). According to the Förster theory of non-radiation energy transfer, the binding distances (r) were also obtained. The process of binding was a spontaneous molecular interaction in which entropy increased and Gibbs free energy decreased, indicating that the interaction between brucine and BSA was driven mainly by hydrophobic force.

[Study on the interaction between fangchinoline and bovine serum albumin].

The binding reaction of fangchinoline with bovine serum albumin was studied at different temperatures by fluorescence quenching spectra, synchronous fluorescence spectra and ultra-violet spectra. It was shown that fangchinoline has a strong ability of quenching the fluorescence of BSA. The Stern-Volmer curve of the fluorescence quenching of BSA by fangchinoline indicated that the quenching mechanism of fangchinoline to BSA was a static quenching. According to the Förster theory of non-radiation energy transfer, the binding distances (r) at different temperature were 2.51 nm (27 degrees C), 2.72 nm (37 degrees C) and 2.89 nm (47 degrees C), respectively, while the binding constants (KA) were 1.05 x 10(5) L x mol(-1) (27 degrees C), 3.31x 10(5) L x mol(-1) (37 degrees C), and 7.24 x 10(5) L x mol(-1) (47 degrees C), respectively. The thermodynamic parameters showed that the interaction of fangchinoline and BSA was mainly driven by hydrophobic force. Synchronous spectrum was used to investigate the conformational changes of BSA.

Study of the interaction of carbamazepine with bovine serum albumin by fluorescence quenching method.

The interaction between carbamazepine (CBZ) and bovine serum albumin (BSA) was studied using fluorescence spectroscopy (FS) and ultraviolet spectroscopy (UV). The experimental results showed that the CBZ could insert into the BSA and quench the inner fluorescence of BSA by forming the CBZ-BSA complex. It was found that both static quenching and non-radiation energy transfer were the main reasons leading to the fluorescence quenching. The apparent binding constants (K) between CBZ and BSA were found to be 1.8 x 10(4) (27 degrees C) and 2.8 x 10(4) (37 degrees C) and the binding site values (n) were 0.97 (27 degrees C) and 1.01 (37 degrees C), respectively. According to the Forster theory of non-radiation energy transfer, the binding distances (r) between CBZ and BSA were 3.6 nm and 3.4 nm at 27 degrees C and 37 degrees C, respectively. The process of the binding was a spontaneous molecular interaction in which entropy increased and Gibbs free energy decreased, indicating that the interaction between CBZ and BSA was mainly driven by the hydrophobic force.

Determination of polyamines by flow injection analysis with a chemiluminescence detector based on their complexation with copper(II).

Through the flow injection analysis experiments, we discovered that an unsaturated complex of Cu(II) and polyamines (spermine, spermidine, putrescine) had a strongly catalytic effect on luminol-H(2)O(2) chemiluminescence (CL) reaction, and that the CL intensity is proportional to the concentrations of polyamines. Based on the automatic formation of an unsaturated complex of polyamines and Cu(II) when the solution containing polyamines passed through a column packed with solid Cu(OH)(2), a new flow injection chemiluminescence analysis method was proposed for the determination of polyamines. The effects of pH, buffer concentration, the concentration of chemiluminescence reagent, and the influence of mixing coil length were examined. Under optimal conditions, the linear range was from 1.0 x 10(-7) mol L(-1) to 1.0 x 10(-5) mol L(-1), and the detection limits were 0.17, 0.38, 0.44 pmol for spermine, spermidine, and putrescine, respectively. Compared with other methods, the advantages of this method include convenience, time-saving and low cost.

[Interaction between strychnine and bovine serum albumin].

AIM: To study the interaction between strychnine and bovine serum albumin. METHODS: Fluorescence spectroscopy and ultraviolet spectroscopy were used. RESULTS: The static quenching and the non-radiation energy transfer are the two main reasons to leading the fluorescence quenching of BSA. The apparent combining constants (K(A)) between strychnine and BSA are 3.72 x 10(3) at 27 degrees C, 4.27 x 10(3) at 37 degrees C, 4.47 x 10(3) at 47 degrees C and the combining sites are 1.01 +/- 0.03. The combining distance (r = 3.795 nm) and energy transfer efficiency (E = 0.0338) are obtained by Förster's non-radiation energy transfer mechanism. CONCLUSION: The interaction between strychnine and BSA was driven mainly by hydrophobic force.

[Interaction of quercetin and bovine serum albumin].

The interaction of quercetin and bovine serum albumin (BSA) was investigated using fluorescence spectroscopy (FS) and ultraviolet spectroscopy (UV). The apparent binding constants (KA) between quercetin and BSA were 2.8 x 10(8) (26 degrees C) and 3.1 x 10(8) (36 degrees C), and the binding sites (n) were 1.7+/-0.02. According to the Förster theory of non-radiation energy transfer, the binding distances (r) were also obtained. The experimental results showed that the quercetin could be inserted into the BSA, quenching the inner fluorescence by forming the quercetin-BSA complex. It was found that both static quenching and non-radiation energy transfer were the main reasons for the fluorescence quenching. The process of binding was a spontaneous molecular interactioln in which entropy increased while Gibbs free energy decreased, indicating that the interaction of quercetin and BSA was driven mainly by hydrophobic force.

Suicidal behavior among inpatients with schizophrenia and mood disorders in Chengdu, China.

This study evaluated the characteristics of suicidal behavior (suicide attempt or suicidal ideation) among 230 consecutively admitted inpatients with schizophrenia and mood disorders in a university hospital in China. The rate of lifetime suicidal behavior was found to be significantly higher in patients with mood disorders (62.4%) than in patients with schizophrenia (38.6%). The rate of suicidal behavior was significantly higher in patients with major depressive disorder (86.8%) than those with bipolar disorders (42.6%). Patients with schizophrenia attempted suicide for the first time earlier in life than the patients with mood disorders. Mood disorder patients, especially those with major depressive disorder, had more and more serious suicide attempts than the patients with schizophrenia.

Microwave-assisted preparation, characterization and photocatalytic properties of a dumbbell-shaped ZnO photocatalyst.

A novel dumbbell-shaped ZnO photocatalyst was successfully synthesized by microwave heating in the present study. The prepared ZnO photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-Vis absorption spectrum (UV-Vis). The results indicated that the prepared ZnO photocatalyst shows a united dumbbell shape with 2 microm diameter and 5 microm length. The photocatalytic activity of the prepared dumbbell-shaped ZnO photocatalyst was evaluated by the degradation of Methylene Blue (MB) in aqueous solution. The effects of pH, catalyst dosage ([ZnO]) and initial concentration of MB ([MB]) on the photocatalytic degradation efficiency of MB were investigated. An optimum condition was determined as pH 7-8, [ZnO]=1.0 g-ZnO L(-1) and [MB]=15 mg-MB L(-1). Under the optimum condition, the decolorization and TOC removal efficiencies of MB at 75 min reaction time were achieved 99.6% and 74.3%, respectively, which were higher than that by the commercial ZnO powder. In addition, the photocatalytic degradation kinetics of MB was also investigated. The results showed that the photocatalytic degradation kinetics of MB fitted the pseudo-first-order kinetics and the Langmuir-Hinshelwood model.

Suicide attempts among patients with psychosis in a Chinese rural community.

OBJECTIVE: To explore the characteristics of psychotic patients with suicide attempts in a Chinese rural community. METHOD: An epidemiological investigation of psychotic patients with suicide attempts among 123,572 population (over 15 years of age) was conducted in Xinjin County, Chengdu. RESULTS: The rate of suicide attempts was found to be 8.17% among all the psychotic patients (906 cases). Patients with affective psychosis showed a significantly higher rate of suicidal attempts (15.3%) than those with schizophrenia (7.5%) (P < 0.005). Suicide attempts were significantly associated with depression and hopelessness in both schizophrenia and affective psychosis (P < 0.001). Patients with suicide attempts were younger and had an earlier age of onset than those without suicide attempts (P < 0.05). Patients with schizophrenia and affective disorders were the major patients with suicide attempts. CONCLUSION: The rate of suicide attempts in psychotic patients may be largely influenced by the illness itself. Community-based services should be necessary for these patients.