Determination of haloperidol and reduced haloperidol in human serum by liquid chromatography after fluorescence labeling based on the Suzuki coupling reaction

A simultaneous method for the determination of haloperidol (HP) and its metabolite, reduced haloperidol (RHP), in human serum was developed by means of high-performance liquid chromatography (HPLC) with fluorescence detection. Suzuki coupling reaction with a fluorescent arylboronic acid, 4-(4,5-diphenyl-1H-imidazol-2-yl)phenylboronic acid (DPA), was employed to convert HP and RHP into highly fluorescent compounds. HP and RHP were extracted from human serum by liquid-liquid extraction with a mixture of n-hexane and isoamyl alcohol (99:1, v/v) and subsequently labeled by reaction with DPA. Separation of DPA derivatives of HP and RHP was performed on a silica column with a mixture of acetonitrile and H(2)O (90:10, v/v) containing triethylamine and acetic acid as a mobile phase. The proposed method allowed sensitive detection of HP and RHP in human serum with a detection limit (at a signal to noise ratio of 3) of 0.22 and 0.20 ng/mL, respectively. The applicability of the method for therapeutic drug monitoring (TDM) was demonstrated by analyzing human serum samples from schizophrenic patients receiving HP.     

真空薄膜浓缩装置的研制及应用研究

介绍了真空薄膜浓缩装置的构造、特征、工作原理及使用方法,并将真空薄膜浓缩法与旋转薄膜浓缩法的工作效率及对热敏性成分含量的影响进行了比较研究。结果表明,两法相比,前者具有仪器容量大、浓缩速度快、浓缩液受热时间短、操作简单及工作效率高等优点。     

Relación entre el parámetro flecha-luz y la carga crítica de pandeo lateral para arcos parabólicos biempotrados bajo diferentes hipótesis de cálculo

Curved graphs that relate the f/L ratio and the λ = qL³/EI_y parameter for clamped arches with the different calculation hypothesis are going to be proposed in this article.It has been necessary to determine the real critical lateral strength of a series of clamped arches considering different calculation hypothesis respect to geometrical linearity and a steel material characteristic.The elastic-plastic material hypothesis with non geometrical linearity considers the existence of residual stresses and initial lateral deflection.     

Tea Classification by Near Infrared Spectroscopy with Projection Discriminant Analysis and Gene Expression Programming

Traditional gene expression programming for classification is designed for binary decisions. Herein, projection discriminant analysis for direct multiclass categorization using gene expression programming is described. Gene expression programming was first employed to examine new synthetic variables that were built as nonlinear combinations of the original features. The data were projected on planes spanned by these new synthetic variables and the nearest centroid was employed to classify new samples. A new objective function was formulated to determine optimum synthetic variables. Direct multiclass categorization using a gene expression programming algorithm was used to classify six tea varieties analyzed by near infrared spectroscopy. Compared with traditional gene expression programming, principal component analysis, and linear discriminant analysis, direct multiclass categorization with gene expression programming algorithm was more efficient. Visual inspection of high dimensional data by this approach also facilitated classification and comprehension of data.     

Facile Synthesis of Cyclodextrin Functionalized Reduced Graphite Oxide with the Aid of Ionic Liquid for Simultaneous Determination of Guanine and Adenine

Here, a facile reduction approach for synthesis of β‐cyclodextrin functionalized reduced graphite oxide with the aid of ionic liquid (βCD/IRGO) was reported. This strategy relies on the simple mixing of pre‐pared aqueous βCD/GO with ionic liquid (IL) at high temperatures, which can bring about a well dispersed βCD/RGO in the utilized IL (βCD/IRGO) with a synchronous evaporation of water. The as‐prepared βCD/IRGO product can be stably re‐dispersed in water (up to 1.0 mg/mL) after washed and dried. And the presented βCD/IRGO composites possess high supramolecular recognition capability and good conductivity for realizing enhanced electrochemical response towards simultaneous detection of guanine and adenine compared with other βCD/carbon (RGO or carbon nanotube) based composites. In the presence of one of analysts, the linear response ranges is 0.03–10.0 μM for guanine and 0.02–7.0 μM for adenine, respectively, with detection limit of 0.01 μM for both guanine and adenine (S/N=3). This ease of making the βCD/IRGO composite will open up possibilities of its diversifier applications.     

6‐Deoxyhexoses from l‐Rhamnose in the Search for Inducers of the Rhamnose Operon: Synergy of Chemistry and Biotechnology

In the search for alternative non‐metabolizable inducers in the l ‐rhamnose promoter system, the synthesis of fifteen 6‐deoxyhexoses from l ‐rhamnose demonstrates the value of synergy between biotechnology and chemistry. The readily available 2,3‐acetonide of rhamnonolactone allows inversion of configuration at C4 and/or C5 of rhamnose to give 6‐deoxy‐d ‐allose, 6‐deoxy‐d ‐gulose and 6‐deoxy‐l ‐talose. Highly crystalline 3,5‐benzylidene rhamnonolactone gives easy access to l ‐quinovose (6‐deoxy‐l ‐glucose), l ‐olivose and rhamnose analogue with C2 azido, amino and acetamido substituents. Electrophilic fluorination of rhamnal gives a mixture of 2‐deoxy‐2‐fluoro‐l ‐rhamnose and 2‐deoxy‐2‐fluoro‐l ‐quinovose. Biotechnology provides access to 6‐deoxy‐l ‐altrose and 1‐deoxy‐l ‐fructose.     

A Prediction for the Critical Temperature of Organic Compounds from the Reduced Melting Temperature

The critical temperature T c of organic chains has been predicted from the observed behaviour for the reduced melting temperature T rm . For a number of carbon atoms sufficiently large, when the odd-even effect vanishes, T rm reaches an approximately constant value, which changes very smoothly with the chain under consideration. Then the melting temperature T m gives immediately a numerical value for T c . If T m is not known, T c can be evaluated alternatively extrapolating the available values for the members of the chain.     

Phylogenetic distribution and structural analyses of cyanobacterial glutaredoxins (Grxs)

Glutaredoxins (Grxs), the oxidoreductase proteins, are involved in several cellular processes, including maintenance of cellular redox potential and iron-sulfur homeostasis. The analysis of 503 amino acid sequences from 167 cyanobacterial species led to the identification of four classes of cyanobacterial Grxs, i.e., class I, II, V, and VI Grxs. Class III and IV Grxs were absent in cyanobacteria. Class I and II Grxs are single module oxidoreductase while class V and VI Grxs are multimodular proteins having additional modules at their C-terminal and N-terminal end, respectively. Furthermore, class VI Grxs were exclusively present in marine cyanobacteria. We also report the identification of class VI Grxs with two novel active site motif compositions. Detailed phylogenetic analysis of all four classes of Grxs revealed the presence of several subgroups within each class of Grx having variable dithiol and/or monothiol catalytic active site motif and putative glutathione binding sites. However, class II Grxs possess CGFS-type highly conserved monothiol catalytic active site motif. Sequence analysis confirmed the highly diverse nature of Grx proteins in terms of their amino acid composition; though, sequence diversity does not affect the overall 3D structure of cyanobacterial Grxs. The active site residues and putative GSH binding residues are uncharged amino acids which are present on the surface of the protein. Additionally, the presence of hydrophilic residues at the surface of Grxs confirms their solubility. Protein-ligand interaction analysis identified novel glutathione binding sites on Grxs. Regulation of Grxs encoding genes expression by light quality and quantity as well as salinity suggests their role in determining the fitness of organisms under abiotic factors.     

The mechanism of photocurrent enhancement of ZnO ultraviolet photodetector by reduced graphene oxide

An ultraviolet (UV) photodetector based on ZnO-reduced graphene oxide (ZnO-rGO) composites have been successfully fabricated. A pure ZnO photodetector was also fabricated by similar method. In comparison with the pure ZnO UV photodetector, the ZnO-rGO photodetector exhibits a much larger photocurrent and a better light-to-dark-current-ratio. The mechanism of photocurrent enhancement was investigated using I-V characteristics, photoluminescence (PL) spectra, transmittance spectra and time-dependent photocurrent analysis. Results show that the photocurrent enhancement of the ultraviolet photodetector is due to the improvement of the carrier lifetime, because the carrier recombination of ZnO were reduced by rGO. It provides a potential way to fabricate high-response UV photodetectors.