Dimerization of recombinant horseradish peroxidase in a reversed micellar system

Recombinant horseradish peroxidase reactivated from E. coli inclusion bodies was studied in a reversed micellar system of AOT in octane. The ability of the recombinant enzyme, in contrast to native horseradish peroxidase, to form a dimeric structure was found. The existence of the dimer was proved by results of sedimentation analysis. Dimer/monomer ratio in the enzyme-containing micelles and dimer catalytic activity were found to depend on the substrate used (pyrogallol, guaiacol, o-dianisidine, o-phenylenediamine). Computer modelling was used to describe possible structures of the dimeric recombinant horseradish peroxidase.     

Identification and characterization of recombinant murine interleukin-6 with a C-terminal pentapeptide extension using capillary reversed phase HPLC-MS and edman degradation

The authors, in previous studies, showed that morphological alterations on gold coated brass pins, extracted after some years of staying in dental roots, are the consequence of a localized corrosion attack, produced by anaerobic bacteria, whose presence is confirmed by the high concentration of sulphur on the most attacked spots. Since, by using a suitable technique of pin inserting, the corrosion should not occur, it was supposed that root resorption could lead to favourable conditions to create corrosion. In order to bear out this assumption, 10 meaningful clinical cases of teeth previously restored by gold coated radicular pins are critically evaluated.     

The five-factor model of personality and managerial performance: Validity gains through the use of 360 degree performance ratings.

This study investigated the usefulness of the five-factor model (FFM) of personality in predicting two aspects of managerial performance (task vs. contextual) assessed by utilizing the 360 degree performance rating system. The authors speculated that one reason for the low validity of the FFM might be the failure of single-source (e.g., supervisor) ratings to comprehensively capture the construct of managerial performance. The operational validity of personality was found to increase substantially (50%–74%) across all of the FFM personality traits when both peer and subordinate ratings were added to supervisor ratings according to the multitrait–multimethod approach. Furthermore, the authors responded to the recent calls to validate tests via a multivariate (e.g., multitrait–multimethod) approach by decomposing overall managerial performance into task and contextual performance criteria and by using multiple rating perspectives (sources). Overall, this study contributes to the evidence that personality may be even more useful in predicting managerial performance if the performance criteria are less deficient. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A rapid reversed phase high performance liquid chromatographic method for the determination of docetaxel (Taxotere) in human plasma using a column switching technique

A rapid, simple and sensitive isocratic high performance liquid chromatography (HPLC) method was developed to measure the concentration of docetaxel in plasma samples with UV detection at 227 nm. The method uses a column switching technique with an Ultrasphere C18 column (75 x 4.6 mm ID, 3 mu, Altex, USA) as clean-up column and a CSC-nucleosil C8 column (150 x 4.6 mm ID, 5 mu, CSC, Montreal, Canada) as the analytical column. The mobile phase consisted of Phosphate buffer (30 mM, pH = 3)-acetonitrile (47:53, v/v) with the flow rates of 1.1 and 1.3 ml min-1 for clean-up and analytical columns, respectively. Paclitaxel was used as an internal standard. The plasma samples were extracted using a solid phase extraction method with Ammonium acetate (30 mM, pH = 5)-acetonitrile (50:50, v/v) as final eluent. The extraction method showed a recovery of 92% for docetaxel. In this system, the retention times of docetaxel and Paclitaxel were 7.2 and 8.5 min, respectively. The detection limit of docetaxel in plasma is 2.5 ng ml-1. This analytical method has a very good reproducibility (7.2% between-day variability at a concentration of 10 ng ml-1). It is applicable in clinical and pharmacokinetic studies.     

The development,verification, and application of a steady-state thermal model for the pusher-type reheat furnace

This article outlines the development of a steady-state thermal model for the pusher-type steel reheating furnace. Problems commonly encountered with this furnace type are skidmark generation, scale formation, and high energy consumption. The objective of the work is to provide a means by which furnace users might assess the effectiveness of changes to current operating practice, proposed furnace modifications, or new furnace designs in controlling these difficulties. Since a requirement imposed on the model is to operate on current PC hardware, the assumptions and modeling procedures necessary to achieve this goal are discussed. The operation of the model, which develops the thermal history of an individual slab or billet as it passes through the furnace, is presented, and each of the three modules that comprise the model is described. Initial verification of the model has been carried out using data obtained in a separate campaign of plant trials on several 32-m furnace reheating slabs, and model predictions for steel temperatures at six locations within the steel are shown to be in good agreement with the experimental results. The model is used to examine the influence of two skid designs and several placement strategies on skidmark severity and energy losses to the skid system. Although skidmark severity at the intermediate stages of heating is shown to be dependent on both the skid type and the location of any offsets, it is demonstrated that the skidmark present in the discharged steel is determined primarily by the skid type employed over the final section of the furnace. The inclusion of a hearth in the furnace soak zone was found to impose the least severe skidmark on the product, reducing the temperature variation over the bottom face from the level of 130 °C incurred by the best of the soak zone skid configurations examined, to the level of ~85 °C. The results suggest that, in the absence of a hearth section, the use of a well-insulated, cold-rider skid system over the majority of the furnace length, followed by a single offset of all skids occurring at the transition to a short section of hot-rider skids near the furnace discharge, is sufficient to suppress the final skidmark to a level very close to the minimum achievable with that particular skid design. When assessed on the basis of minimizing both the final skidmark and the energy loss to the skid system, this configuration was found to be the best of the skid layouts examined.     

Neurodegeneration induced by reversed microdialysis of NMDA; a quantitative model for excitotoxicity in vivo

Analogs of a partial sequence peptide of laminin, i.e., Tyr-Ile-Gly-Ser-Arg (YIGSR) analogs and Cys-Asp-Pro-Gly-Tyr-Ile-Gly-Ser-Arg (CDPGYIGSR) analogs, were prepared by the solid-phase method and their inhibitory effects on experimental metastasis of B16-BL6 melanoma cells were examined. YIGSR analogs in which Ile was replaced by other hydrophobic amino acids (Met, Leu, Phe) were inhibitory. Cys-containing analogs of YIGSR were also prepared, but were less active than the parent peptide, YIGSR. Among them, CYIGSR was easily oxidized to form a disulfide bond. A Cys-containing YIGSR analog cyclized through a disulfide bond, cyclo(CYIGSRC)G, was prepared. The disulfide bond formation was performed on the resin by the silyl chloride-sulfoxide method and by the iodine oxidation method. The yield of the silyl chloride-sulfoxide method was much better than that of the iodine oxidation method.     

Mapping the prion protein using recombinant antibodies

The fundamental event in prion disease is thought to be the posttranslational conversion of the cellular prion protein (PrPC) into a pathogenic isoform (PrPSc). The occurrence of PrPC on the cell surface and PrPSc in amyloid plaques in situ or in aggregates following purification complicates the study of the molecular events that underlie the disease process. Monoclonal antibodies are highly sensitive probes of protein conformation which can be used under these conditions. Here, we report the rescue of a diverse panel of 19 PrP-specific recombinant monoclonal antibodies from phage display libraries prepared from PrP deficient (Prnp0/0) mice immunized with infectious prions either in the form of rods or PrP 27-30 dispersed into liposomes. The antibodies recognize a number of distinct linear and discontinuous epitopes that are presented to a varying degree on different PrP preparations. The epitope reactivity of the recombinant PrP(90-231) molecule was almost indistinguishable from that of PrPC on the cell surface, validating the importance of detailed structural studies on the recombinant molecule. Only one epitope region at the C terminus of PrP was well presented on both PrPC and PrPSc, while epitopes associated with most of the antibodies in the panel were present on PrPC but absent from PrPSc.     

A kriging interpolation strategy for the optimization of Acidithiobacillus ferrooxidans biomass production using fed-batch bioreactors

In this work, a procedure for the optimization of Acidithiobacillus ferrooxidans biomass production in fed-batch reactors using a model based on optimal spatial interpolation of experimental data is proposed. The approach is useful in those cases where specific growth and substrate consumption rates are unknown. Based on interpolation, the optimal values of biomass and substrate concentrations set points are obtained at the minimum of 2-dimensional cost function. In the fed-batch reactor biomass and substrate concentrations are controlled at their set points by changing the input flow and its concentration. We propose a minimum variance control strategy which improves the classical proportional plus integral control. Since the interpolation is optimal, the proposed linear control strategy allows obtaining a tight minimized upper bound of the variance error in the controlled variables.     

创新人才培养模式创建一流本科大学

不断更新教育思想，转变教育观念，创新人才培养模式；改善教学环境，实施弹性灵活的教学运行机制：建立创新实践基地开放性的管理与运行机制；构建以“合格＋拓展”为特色的多样化培养制度，满足学生多样化的教育需求，创建一流本科大学。     

Megazol combined with suramin: a chemotherapy regimen which reversed the CNS pathology in a model of human African trypanosomiasis in mice

Chemotherapy for human African trypanosomiasis (HAT), or sleeping sickness, is unreliable because of resistance, refraction and toxic and adverse side-effects. Using a long-term experimental model of HAT with involvement of the central nervous system (CNS), we tested the ability of a megazol and suramin combination treatment to eliminate CNS trypanosomes. This consisted of 20 mg suramin per kg body weight administered intraperitoneally (i.p.), followed 24 h later by 4 daily doses (80 mg/kg) of megazol given either i.p. or per os. One week post-treatment, neurological disorders had disappeared. One of 15 mice relapsed in each application group at 81 and 98 days after treatment, respectively. At six months, no signs of relapse were seen in remaining mice, indicating that this chemotherapy regimen was curative. Immunohistochemical (astrocytosis) and histological (inflammatory lesions) examinations of brain tissues showed that animals returned to normal from 2 months post-treatment. These results suggest that the megazol-suramin combination reversed the CNS pathology in this model.     

Cultivating a moral sense of nursing through model emulation

This paper reports part of a longitudinal research project, which sought to capture students' conceptualization of caring practice as they progressed to different levels of study in a nursing diploma programme in Hong Kong. Model emulation was found to be an effective means of focusing students' learning processes on the moral aspects of nursing practice. The theory of model emulation from a Chinese perspective and how it is applied to create a learning context to allow students to acquire a moral sense of nursing are discussed. The participating students are invited to be sincere enquirers in the pursuit of the good embedded in practice through introspective self-examination and dialogue. They are asked to describe and share their experience of positive and negative examples of nursing in written accounts. Van Kaam's phenomenological method was adopted to explicate the good and bad constituents of nursing from these examples, with the students assuming an active role in the explication process. The explication reveals that the students were able to articulate the good and bad practices in a variety of patient care situations.     

Care of the older hypothermic patient using a self-care model

Diphyllobothriases are spread in the population of the Pur River basin unevenly. The population on the lower Pur is affected little, but that on the upper Pur and its tributaries is affected much more. This is largely accounted for by what fishes are prevalent in the diet of the local population and how they consume fish. In the past 30 years, the infection of fish with Diphyllobothrium latum larvae and the prevalence of the population's infection have reduced in some areas of the Pur River basin. Among other things, this is associated with man-made impacts on the local water reservoirs (development of areas, gas extraction, etc.), which influences the first and second intermediate D.latum hosts.     

Normal-phase liquid chromatography of plant hormones using reversed cholic acid micelles as the mobile phase

When several plant hormones with similar structures are present in a sample, conventional analytical methods are not sufficiently selective to effectively differentiate them. However, the excellent selectivity of micellar liquid chromatography allows similarly structured compounds to be easily differentiated. We used reversed cholic acid micelles dissolved in tetrahydrofuran as the mobile phase in normal-phase chromatography of seven plant hormones. Our results conformed closely to those predicted by the pseudophase micellar liquid chromatography theory. The chromatographic efficiencies were calculated from the peak width and the retention times, and we compared these values with those obtained by reversed-phase chromatography using sodium dodecyl sulfate mobile phase in water. To test the efficiency of this selective method for the analysis of plant tissues that may also contain contaminants, we applied it to homogeneous suspensions of spiked maize roots. Recoveries ranged from 91 to 110%, the relative standard deviations were between 0.46 and 10.03%, and the detection limits were between 0.08 and 0.80 micrograms g-1.     

The effect of recombinant growth hormone on the strength of ileal anastomoses in a rat model

OBJECTIVE: In gynecologic surgery, the ileum is the primary site of bowel injury. Recombinant growth hormone (rGH) has been shown to improve the strength of colonic anastomoses in experimental models. The purpose of this study is to evaluate the effect of rGH on small bowel anastomoses, specifically in the ileum. METHODS: Twenty large female rats underwent segmental ileal resections and end-to-end ileoileostomies. The rats were randomized to be treated for 7 postoperative days with either rGH (2.0 mg/kg/day) or placebo starting on the day of surgery. On the seventh postoperative day, a segment of ileum surrounding the anastomosis was resected. The anastomoses were tested for breaking strength on a tensiometer and for tissue concentrations of hydroxyproline. RESULTS: The ileal anastomotic breaking strength in the rGH group was 163.5 +/- 6.0 g (mean +/- standard error). In the placebo group, the breaking strength of ileal anastomoses was 125.0 +/- 3.0 g (P < .001). No significant difference was demonstrated with respect to the hydroxyproline concentration between the rGH group (15.2 +/- 2.0 micrograms/mg) and the placebo group (14.6 +/- 1.0 micrograms/mg). CONCLUSION: In an animal model, a 31% increase in ileal anastomotic breaking strength was induced by rGH administration. With further research this may translate into decreases in the surgical complications that occur in ileal anastomoses. Furthermore, these serve as preliminary data to a study that evaluates the effect of rGH on ileal anastomoses in radiation-injured bowel.     

A confirmatory test of a model of performance determinants.

The total variance in any observed measure of performance can be attributed to 3 sources: (1) the correlation of the measure with the latent variable of interest (i.e., true score variance), (2) reliable but irrelevant variance due to contamination, and (3) error. A model is proposed that specifies 3, and only 3, determinants of the relevant variance: declarative knowledge, procedural knowledge and skill, and volitional choice (motivation). The 3 determinants are defined, and their implications for performance measurement are discussed. Using data from the US Army Selection and Classification Project (Project A), it was found that the model fits a simplex pattern to the criterion data matrix. The predictor–determinant correlations are also estimated. Analyses of the data with LISREL provided strong confirmation of the model. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Test of a model linking employee positive moods and task performance.

Past empirical evidence has demonstrated that employees' positive mood states predict task performance. This study extends previous research by proposing and testing a model that examines mediating processes underlying the relationship between employee positive moods and task performance. Two longitudinal studies used data collected from 306 (Study 1) and 263 (Study 2) insurance sales agents in Taiwan. The results showed that employee positive moods predicted task performance indirectly through both interpersonal (helping other coworkers and coworker helping and support) and motivational (self-efficacy and task persistence) processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Testing a conceptual model of working through self-defeating patterns.

The present study developed and examined a conceptual model of working through self-defeating patterns. Participants were 390 college students at a large midwestern university. Results indicated that self-defeating patterns mediated the relations between attachment and distress. Also, self-esteem mediated the link between self-defeating patterns and depression, whereas social self-efficacy mediated the association between self-defeating patterns and interpersonal distress. A total of 33% of the variance in self-defeating patterns was explained by attachment anxiety and avoidance; 39% of the variance in self-esteem and 13% of the variance in social self-efficacy were explained by self-defeating patterns and/or attachment anxiety; 50% of the variance in depression was explained by attachment anxiety, self-defeating patterns, and self-esteem; 45% of the variance in interpersonal distress was explained by attachment anxiety and avoidance, self-defeating patterns, and social self-efficacy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparison of the retention characteristics of aromatic and aliphatic reversed phases for HPLC using linear solvation energy relationships

The similarities and differences in retention characteristics of aromatic and aliphatic phases have been elucidated by the use of linear solvation energy relationships (LSERs). Three aromatic phases and three aliphatic phases were investigated in a series of mobile phases. The results of LSERs on a polymer-based aromatic phase, poly(styrene-divinylbenzene) resin (PRP-1) are very different from those on either silica- or zirconia-based aromatic and aliphatic phases. Retention on all aromatic and aliphatic phases except PRP-1 is dominated by two factors: the solute size and hydrogen bond acceptor basicity. On the other hand, in addition to these two major contributions, retention on PRP-1 is markedly influenced by the solute hydrogen bond donor acidity. We believe that PRP-1 exhibits a more adsorption-like retention mechanism than do the other phases. With the inorganic oxide-based phases, the aromatic phases are less retentive than the aliphatic phases but show a larger dependence on molecular polarizability. The enhanced polarizability of aromatic phases is the likely cause of some differences in their chromatographic selectivity relative to the aliphatic phases.