New and efficient synthesis of azabicyclo[4.4.0]alkane amino acids by Rh-catalyzed cyclohydrocarbonylation

[reaction: see text] Highly efficient syntheses of azabicyclo[4.4.0]alkane amino acids were achieved by Rh-catalyzed cyclohydrocarbonylation of dipeptides bearing a terminal olefin moiety and a heteroatom nucleophile.     

Determination of remoxipride in human plasma and urine by reversed-phase ion-pair high-performance liquid chromatography.

A sensitive method is described for the measurement of remoxipride in human plasma and urine. Remoxipride and its internal standard are extracted from plasma or urine at pH 12 with a mixture of hexane and methyl tert.-butyl ether. After washing the organic phase with base, the compounds are extracted into acid and analyzed on a C18 column with ultraviolet detection at 214 nm. The mobile phase is composed of acetonitrile and aqueous buffer (sodium perchlorate and phosphoric acid, pH 1.7). The limits of reliable quantitation for remoxipride are 12.5 and 50 ng/ml for plasma and urine, respectively. The run times are 6 min for plasma and 3 min for urine. The method has been successfully used to assay remoxipride clinical study samples. This mobile phase has also been successfully applied to the analysis of other basic drugs such as cimetidine, codeine, diltiazem and quinidine with minor modifications.     

A joint measurement of efficiency and effectiveness for non-storable commodities: Integrated data envelopment analysis approaches

Efficiency and effectiveness for non-storable commodities represent two distinct dimensions and a joint measurement of both is necessary to fully capture the overall performance. This paper proposes two novel integrated data envelopment analysis (IDEA) approaches, the integrated Charnes, Cooper and Rhodes (ICCR) and integrated Banker, Charnes and Cooper (IBCC) models, to jointly analyze the overall performance of non-storable commodities under constant and variable returns to scale technologies. The core logic of the proposed models is simultaneously determining the virtual multipliers associated with inputs, outputs, and consumption by additive specifications for technical efficiency and service effectiveness terms with equal weights. We show that both ICCR and IBCC models possess the essential properties of rationality, uniqueness, and benchmarking power. A case analysis also demonstrates that the proposed novel IDEA approaches have higher benchmarking power than the conventional separate DEA approaches. More generalized specifications of IDEA models with unequal weights are also elaborated.     

Exact stability regions for quartic polynomials

Given an arbitrary real quartic polynomial, we find the exact region containing the coefficients of the polynomial such that all roots have absolute values less than 1.     

Determining the optimal production policy for a system with imperfect production and shortage

The classic EPQ model assumes that items are produced of perfect quality and no shortage is permitted. In the real world situation, however, due to process deterioration or other factors, the occurrence of imperfect quality items is inevitable. This paper develops an extended economic production quantity (EPQ) model with imperfect production, shortage, and imperfect rework. We assume that the quality scan is conducted during the production. The scanned imperfect items are classified as the repairable and scrap. We consider that not all of the repairable items can be restored to meet the specified quality standard. Only some portion of defective items can be restored as normal items, the other results in defective, due to repair failure, can be sold at a discounted price to a secondary market. The renewal reward theorem is utilized to deal with the variable cycle length. The production quantity and the shortage level are determined in an optimal manner so as to minimize the average system cost. A numerical example is used to demonstrate its practical usage. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Direct contact versus solvent-shared ion pairs in NiCl2 electrolytes monitored by multiplet effects at Ni(II) L edge X-ray absorption

We investigate the local electronic structure in aqueous NiCl2 electrolytes by Ni L edge X-ray absorption spectroscopy. The experimental findings are interpreted in conjunction with multiplet calculations of the electronic structure and the resulting spectral shape. In contrast to the situation in the solid, the electronic structure in the electrolyte reflects the absence of direct contact Ni-Cl ion pairs. We observe a systematic change of the intensity ratio of singlet- and triplet-related spectral features as a function of electrolyte concentration. These changes can be described theoretically by a change in the weight of transition matrix contributions with different symmetries. We interpret these findings as being due to progressive distortions of the local symmetry induced by solvent-shared ion pairs.     

Genotyping of two single nucleotide polymorphisms in 5,10-methylenetetrahydrofolate reductase by multiplex polymerase chain reaction and capillary electrophoresis

Two single nucleotide polymorphisms (SNPs) of 5,10-methylenetetrahydrofolate reductase (MTHFR) gene, A1298C and C677T, were widely considered to be related with various neoplasia disorders. We established a simple and effective capillary electrophoresis (CE) method for detection of two SNPs in MTHFR gene simultaneously. DNA samples were amplified by multiplex PCR with universal fluorescence-labeled primer and analyzed by single-strand conformation polymorphism (SSCP)-CE method. The CE method was performed using 1.5% hydroxyethyl cellulose in 1× TBE buffer containing 1 M urea. The PCR products after SSCP procedure were electrokinetically injected at −10 kV, 30 s. Separation voltage was −6 kV and the temperature was set at 20 °C. The optimal SSCP-CE method was applied to detect two polymorphisms in MTHFR gene of acute lymphoblastic leukemia (ALL) and attention-deficit/hyperactivity disorder (ADHD) patients. Genotyping results were evaluated in terms of relationships between outcomes for ADHD patients after ALL chemotherapy and ALL disease. The SSCP-CE method and multiplex PCR with universal fluorescence primer were used as the fast technique for screening two SNPs in MTHFR gene, A1298C and C677T. The genotyping data were coincident with DNA sequencing. This SSCP-CE method was found feasible for detecting mutation of MTHFR gene in populations.     

Synthesis and Characterization of Iron Nanowires

The iron nanowires can be fabricated via the process in which sodium borohydride reduces iron salts in external magnetic field. The iron nanowires are found to be covered by passivated layers of iron oxide which prevent the oxidation of iron nanowires. In this process, the boron will include in iron nanowires. The average length and diameter of iron nanowires is around 1.2 micrometers and 60 nanometers, respectively. According to ICP results, the contents of B and Fe are about 1.98 wt% and 87.04 wt%, respectively, in iron nanowires. A wide variety of equipment is used to investigate the morphological, microchemical, and structural characteristics of the newly synthesized iron nanowires ––– e.g., XRD, FE‐SEM, HR‐TEM, VSM and XANES. XANES analysis indicates the boron in iron nanowires exists in the form of B₂O₃. The saturation magnetization and the coercive force of iron nanowires are 157.93 emu/g and 9.74 Oe, respectively. In‐situ images of synthesized iron nanowires during reduction process in magnetic field are observed by NSRRC transmission X‐ray microscope. Thus, this study develop a novel process to produce iron nanowires with large quantitates and can control its length and diameter by various the concentration of precursors for various applications.     

Production of l-DOPA by tyrosinase immobilized on modified polystyrene

Mushroom tyrosinase was immobilized on modified polystyrene—polyaminostyrene (PSNH) and polymethylchloridestyrene (PSCL)—to produce l-DOPA from l-tyrosine. Glutaraldehyde was used as an activating agent for the PSNH to immobilize the tyrosinase and 10% (w/v) glutaraldehyde was optimal in conferring the highest specific activity (11.96 U/g) to the PSNH. Methylchloride on the PSCL was directly linked with the tyrosinase, and 1.5 mmol of Cl/g was optimal in attaining the specific activity of 17.0 U/g. The temperature and optimal acidity were, respectively, 60°C and pH 5.5 for the PSNH, and 70°C and pH 3.0 for the PSCL. In a 50-mL batch reactor working over 36 h, the l-DOPA production rate at 30°C was 1.44 mg/(L·h) for the PSNH and 2.33 mg/(L·h) for the PSCL. The production rate over 36 h was 3.86 mg/(L·h) for the PSNH at 60°C and 5.54 mg/(L·h) for the PSCL at 70°C. Both of the immobilized enzymes showed a remarkable stability with almost no change in activity after being stored wet. The operational stability study indicated a 22.4% reduction in l-DOPA production for the PSNH and an 8.63% reduction for the PSCL over seven runs (each run was for 144h at 30°C) when the immobilized enzymes were used under turnover conditions. The immobilized tyrosinase was more stable on the PSCL than on the PSNH.     

Rhodamine‐Ethylenediol,A Novel Vital Fluorescent Probe for Labelling Alkaline Phosphatase‐Rich Organelles

Zebrafish have received considerable attention as an organism‐based model in the development of pharmacological agents.^1,2 Many small molecules applied to zebrafish show important behaviours and may constitute new kinds of markers for clinical purposes.³ Analysis of these molecules can facilitate the development of useful tools for monitoring environmental changes.⁴ Many chemicals that are toxic to the environment are known to influence the sensory systems of humans⁵ and fish.⁶ One important sensory system in all fish is the lateral line organ,⁷ which is readily accessible for the assessment of environmental changes.⁸ Neuromasts, which are located on the surface of the fish body, are one of the major components of the lateral lines of the zebrafish.⁹ Copper‐enriched water is known to affect the olfactory system in fish. Therefore, small molecules that induce specific patterns in the neuromasts of zebrafish should provide an important animal model with which to explore the effects of environmental changes on the sensory system.^10,11 Recently, chemical sensors based on the rhodamine skeleton¹² have been designed to specifically detect metal ions, such as Cu(II)¹³ and Fe(III)/Hg(II),¹⁴ in zebrafish. However, there has been no report of these rhodamine derivatives used in the specific recognition of the sensory system of zebrafish. Commonly, the sensory system is studied with antibody staining assays of scarified fish. Here, we report that a new rhodamine derivative can be used as a fluorescent chemical probe to visualize the neuromasts and intestinal villi of living zebrafish. Based on the specific recognition of this area in zebrafish, we narrowed the possible enzymes targeted by this rhodamine probe to alkaline phosphatase and confirmed this with a binding assay. It is a well‐recognized challenge to develop a fluorescent chemical probe that specifically recognizes a particular enzyme. Furthermore, the transfer of phosphate groups to certain enzymes can activate their catalytic reactivity, triggering a cascade reaction in a signal transduction pathway. The alkaline‐phosphatase‐specific recognition by this rhodamine derivative may be applicable to clinical purposes.