Comparison of the baroreceptor-heart rate reflex effects of moxonidine, rilmenidine and clonidine in conscious rabbits

Immobilization of a protease, Flavourzyme, by covalent binding on various carriers was investigated. Lewatit R258-K, activated with glutaraldehyde, was selected among the tested carriers, because of the highest immobilized enzyme activity. The optimization of activation and immobilization conditions was performed to obtain high recovery yield. The activity recovery decreased with increasing carrier loading over an optimal value, indicating the inactivation of enzymes by their reaction with uncoupled aldehyde groups of carriers. The buffer concentrations for carrier activation and enzyme immobilization were optimally selected as 500 and 50 mM, respectively. With increasing enzyme loading, the immobilized enzyme activity increased, but activity recovery decreased. Immobilization with a highly concentrated enzyme solution was advantageous for both the immobilized enzyme activity and activity recovery. Consequently, the optimum enzyme and carrier loadings for the immobilization of Flavourzyme were determined as 1.8 mg enzyme/mL and 0.6 g resin/mL, respectively.     

Transitional pre-B-cell acute lymphoblastic leukemia of childhood is associated with favorable prognostic clinical features and an excellent outcome: a Pediatric Oncology Group study

The presenting characteristics and survival of children with the newly recognized transitional cell pre-B immunophenotype of acute lymphoblastic leukemia (ALL) are compared with those of children with pre-B ALL to determine the clinical significance of the new phenotype. Patients with transitional pre-B ALL (n = 17), defined by lymphoblasts expressing cytoplasmic and surface mu heavy chains without kappa or lambda light chains, have lower initial leukocyte counts (p = 0.02) and a higher frequency of DNA indexes > 1.16 (p < 0.001) than patients with pre-B ALL (n = 501), whether or not cases with the unfavorable prognostic (1;19) translocation are included in the analysis. Patients with transitional pre-B ALL lack FAB L3 morphology, bulky extramedullary disease, surface kappa or lambda chains, and the (8;14), (8;22), and (2;8) translocations, features that characterize the syndrome of B-cell ALL. The 4-year relapse-free survival result for children with transitional pre-B ALL appears better than that for children with pre-B ALL (93.3 +/- 17% versus 72.9% +/- 4.6%), but this difference is not statistically significant. We conclude that patients with transitional pre-B ALL have a very favorable prognosis in the context of the therapy used in this study.     

Understanding student attitudes of mobile phone features: Rethinking adoption through conjoint,cluster and SEM analyses

Young adults have been labelled as one of the most important segments for mobile phones, however there is little empirical evidence to indicate how these young adults value the feature richness of their devices. This research presents a richer view of mobile phone user preferences and perceptions by applying methodologies from the marketing and information systems domains. Conjoint analysis provides insights into how students value various mobile phone applications and tools. Cluster analysis extracts salient and homogenous consumer segments from the conjoint analysis output. Structural equation modelling then explores how antecedents to attitude may differ by the elicited consumer segments.     

Understanding the role of competition in video gameplay satisfaction

One of the key elements in many video games is competition. Based on Self-Determination and Flow theories, this paper explores the process through which competition makes a video game satisfying. A structural model that examines the impacts of Situational Competitiveness (manipulated via modes of competition) and Dispositional Competitiveness (as a personality trait) on gameplay experience is proposed and validated. The results show that the perception of video game competitiveness has a strong effect on Flow experience and Satisfaction. While an individual’s personality impacts the perception of a game’s competitiveness, this perception can also be influenced by the mode of competition.     

The Comparison of MTDATA with the Melting/Freezing Point Curves of ITS-90 Metal Fixed Points

The International Temperature Scale (ITS-90) is defined in part by a series of metal freezing points between 156 °C and 1,084 °C. These freezing-point cells provide reference temperatures with an uncertainty of realization claimed to be in the range of several tenths of a millikelvin. The impurities in the nominally 99.9999 % pure metals make a major contribution to the uncertainty of realization of the fixed-point temperature. Recently, a new method to correct for the influence of the impurities by summing the individual contributions of each impurity has been suggested. This method is referred to as the “sum of individual estimates” (SIE). NPL is a partner in a Euromet project to improve the realization of ITS-90 metal fixed points. As part of this project, NPL is particularly interested in the fixed-point cells of tin (231.928 °C) and aluminum (660.323 °C). This article describes the use of a thermodynamic model, embodied in NPL’s MTDATA software, to estimate the initial drop in the freezing temperature and the temperature decrease during freezing using both equilibrium and “Scheil” approaches. Calculations of this type establish the effect of single elements, and with the chemical analysis of the metal, enable an estimation of the whole freezing curve. This has been done for a sample of tin from this laboratory, and thereafter, the theoretical curves are compared with previously published experimental data on impurity-doped aluminum, with good agreement, e.g., better than 1 mK over most of the curve for 76 μg · g⁻¹ Ag in Al.     

Patent information: an historical perspective

An historical survey of one specific technical field, as illustrated in patent disclosures, is presented. The field is umbrellas, parasols and walking sticks, from the first British patent of 1780 up to the present day, using classified abridgements in bound volumes of hard copy until the mid 1970s and online databases thereafter. More detailed analyses of the last 20 years are provided. Unlike many recent rapidly developing fields, this field has changed relatively little over two centuries; annual inputs are comparable since the middle 1800s, while many similar solutions to recurrent problems resurface periodically. Nevertheless, discernible commercially and technically significant improvements occur throughout this period, as well as many short-lived tangential developments. Some reasons for this pattern are suggested.     

CHP development in Denmark Role and results

Energy conservation and restructuring towards more energy-efficient technology have been keywords in Danish energy policy in the 1970s and 1980s. This has been reflected especially in domestic heating, where gross energy consumption per square metre has dropped approximately 45% from the early 1970s onwards. This drop is directly related to the massive expansion of combined generation of heat and power (CHP) effected in the same period. Consequently, some 30% of Danish heat requirements are now met by CHP. The intention is to increase this share by a further 7% over the next decade, resulting in a 37% share of Denmark's total heat requirements by CHP in the year 2000.     

埋地管道事故原因分析

阐述了埋地管道事故的危害;分析了埋地管道事故的原因;提出了降低事故发生几率的几点建议。     

Evidence of a systematic deviation of the isotopic composition of neon from commercial sources compared with its isotopic composition in air

Results are reported of a study concerning the variation in isotopic composition of a limited number of neon samples of commercial origin and the resulting influence on the temperature of the triple point of this element. All seven neon samples investigated were found to contain more 22Ne than neon in air, and the amount fraction of 22Ne varied by as much as 0.2% from sample to sample. This variation corresponds to a range of triple-point temperatures (Ttp) of more than 200 microK, much larger than the state-of-the-art uncertainty in the realization of this phase transition for metrological purposes. Deviations in the amount fractions of 21Ne were irrelevant, as far as their effect on T(tp) is concerned, though they may have relevance to other isotope studies. Ratios of amounts of neon isotopes at IRMM-Geel were obtained using the same measurement procedures, and instrumentation developed in the framework of the redetermination of the Avogadro constant and all significant sources of uncertainty were taken into account. The repeatability of the ion current ratio measurements on individual samples was 5 x 10(-5) relative. All uncertainty statements are made following the ISO/BIPM Guide to the Expression of Uncertainty in Measurements. Whereas these results proved unexpected, a more comprehensive study will follow incorporating a much wider range of samples of commercial origin.