bluuebunny/crossref_metadata_2025_split huggingface dataset:
Noncompetitive, Ca2 ‐independent inhibition of pyruvate dehydrogenase phosphatase by fluphenazine
Authors: Bak Choong‐Il , Huh Jae‐Wook , Hong Sungyoul , Song Byoung‐Joon 
Published: July 2007

AbstractThe effects of two different classes of calmodulin antagonists on the catalytic activities of purified pyruvate dehydrogenase (PDH) phosphatase and PDH complex (PDC) were studied. In general, PDH phosphatase was more strongly inhibited than PDC by the calmodulin antagonists with the following potency order: fluphenazine>chlorpromazine>thioridazine>trifiupromazine. Promazine and two sulfonamides (W‐5 and W‐7) did not suppress PDH phosphatase activity at 1 mM concentrations, while about 20% of PDC activity was inhibited by these antagonists. Fluphenazine‐mediated inhibition of PDH phosphatase was observed with the purified PDC as well as intact mitochondria. Although Ca2+ stimulates PDH phosphatase activity, the addition of exogenous Ca2+ did not overcome the inhibition by calmodulin antagonists. These results suggest that the suppression of PDH phosphatase activity is dependent upon the structure of the individual calmodulin antagonist and appears to be Ca2+‐independent. Kinetic analysis showed a noncompetitive inhibition of PDH phosphatase by fluphenazine, indicating that it binds to different site(s) from the catalytic site of the enzyme.
Purification and characterization of tripeptidyl peptidase I from Dictyostelium discoideum
Authors: Krimper Robert P. , Jones Theodore H. D. 
Published: July 2007

AbstractA tripeptidyl peptidase I from Dictyostelium discoideum was purified 744‐fold to near homogeneity. The enzyme is 214 kDa in size and is composed of two monomers with a Mr of 107 kDa. It has two pH optima at pH 4.5 and 5.9 and is a serine peptidase with no aminopeptidase or dipeptidyl peptidase activity. The enzyme was relatively specific showing activity on ala‐ala‐phe‐p‐nitroaniline but also acted on substrates with proline in the Pi position in contrast to mammalian TPP I. The Km values of the enzyme at pH 4.5 for ala‐ala‐phe‐, ala‐phe‐pro‐ and ala‐ala‐pro‐p‐nitroanilines were 271μM, 437μM and 888μM, respectively. The enzyme is most abundant during the amoeba stage of the life cycle but is present in the early stages of development and may therefore have a dual role in the organism in mobilizing amino acids or in processing specific peptides or proteins.
Superoxide and Iron: Partners in Crime
Authors: Liochev Stefan I. , Fridovich Irwin 
Published: July 2007

AbstractSuperoxide (O2 ) poses multiple threats, which are diminished by a family of metalloenzymes, the superoxide dismutases. Among the damaging effects of O are direct oxidation of low‐molecular2 weight reductants; inactivation of a select group of enzymes; and reaction with NO to yield the strong oxidant, peroxynitrite. Of even greater import is the ability of O to univalently oxidize the [4 Fe2 4 S] clusters of dehydratases, which causes release of iron. The “free” iron, which is kept reduced by cellular reductants, then reduces hydroperoxides to hydroxyl or alkoxyl radicals. Because the “free” iron will preferentially bind to anionic polymers, such as nucleic acids, or to anionic surfaces, such as cell membranes, these radicals will be generated adjacent to these vital targets and will preferentially attack them. O and iron can thus be viewed as part2 ners in crime, and reciprocal regulatory effects between iron and O2 may be anticipated. These are discussed.
Microsomal Carbonyl Reductase Responsible for Reduction of 4‐Phenyl‐3‐buten‐2‐one in Rats
Authors: Okamoto Yuji , Kitamura Shigeyuki , Takeshita Mitsuhiro , Ohta Shigeru 
Published: July 2007

Abstracttrans‐4‐Phenyl‐3‐buten‐2‐one (PBO), a flavoring additive, was transformed to the carbonyl‐reduced product, trans‐4‐phenyl‐3‐buten‐2‐ol (PBOL) by rat liver microsomes, but not by liver cytosol, in the presence of NADH or NADPH. PBOL formed was identified by comparison with an authentic sample. The reductase activity was not inhibited by quercitrin, an inhibitor of cytosolic carbonyl reductase. The carbonyl reduction product of PBO by liver microsomes was identified as the R‐enantiomer of PBOL by HPLC analysis. Rat blood also exhibited the carbonyl reductase activity in the presence of NADH or NADPH, but to a lesser extent.
On the Mode of Inhibition of Eukaryotic Protein Synthesis by ADP‐Ribosylation of Elongation Factor 2
Authors: Nurten Rustem , Albeniz Lsil , Bermek Engin 
Published: July 2007

AbstractThe exchange of free guanine nucleotides with guanine nucleotides bound to elongation factor 2 (EF‐2) and to the EF‐2‐ribosome complex, and the effect of ADP‐ribosylation of the EF‐2 thereon, were investigated by nitrocellulose filter assay. Under the experimental conditions, stoichiometric amounts of guanine nucleotides were bound, in particular, to ternary complexes of EF‐2 with biphasic kinetics. The exchange kinetics were similarly biphasic in all cases. Ribosomes appeared to have variable effects on the exchange kinetics, depending on the type of nucleotide bound. Thus, in their presence, the rate and magnitude of the fast exchange of nucleotides revealed increasing values in the order GTP (GXP) > GTP gamma S > GDP. ADP‐ribosylation had no inhibitory effect on the binding of guanine nucleotides to EF‐2 or to the EF‐2‐ribosome complex but reduced significantly the fast exchange of GTP (GXP) and GTP gamma S bound to the EF‐2‐ribosome complex. The effect of ADP ribosylation on the fast exchange of GDP in binary and ternary complexes was less pronounced. The mechanism of inhibition of protein synthesis by ADP‐ribosylation of EF‐2 is discussed in view of these data.
Stability of Alkyl‐Dihydroxyacetonephosphate Synthase in Human Control and Peroxisomal Disorder Fibroblasts
Authors: Biermann Jan , Gootjes Jeannette , Wanders Ronald J. A. , Bosch Henk Van Den 
Published: July 2007

AbstractAlkyl‐dihydroxyacetonephosphate synthase (alkyl‐DHAP synthase) is a peroxisomal enzyme that plays a key role in ether phospholipid biosynthesis. To determine the turnover of alkyl‐DHAP synthase in several peroxisomal disorders, pulse‐chase experiments were performed. In control fibroblasts, mature alkyl‐DHAP synthase displayed a half‐life of 23 +/‐ 12 h. In Zellweger syndrome and rhizomelic chondrodysplasia punctata fibroblast cell lines, in which alkyl‐DHAP synthase cannot be imported into peroxisomes, the enzyme was mainly detected in its precursor form. This precursor form showed a much shorter half‐life, 5 +/‐ 2 h. In contrast, when the precursor protein accumulated inside the peroxisome of a particular neonatal adrenoleukodystrophy cell line in which processing does not take place, a half‐life of 18 +/‐ 8 h, resembling that of the mature protein in controls, was observed. In a cell line from a patient with a single deficiency in the activity of alkyl‐DHAP synthase, the mature form was detected and its radioactivity decreased with a half‐life of 16 +/‐ 7 h. Collectively, these results provide an explanation for the instability of alkyl‐DHAP synthase outside its target organelle. Additionally, they indicate that both the precursor and mature form of alkyl‐DHAP synthase exhibit considerable intraperoxisomal turnover.
Solving the strategy paradox: how to reach for the fruit without going out on a limb
Authors: Raynor Michael E. 
Published: July 2007

PurposeThe author points out that the same strategic behaviors that are associated with great success are also associated with failure. That is, the greatest rewards pose the greatest risks. He explains how corporations should manage risk differently at different levels of responsibility using the concepts of Requisite Uncertainty and strategic flexibility.Design/methodology/approachThe author reexamines two classic examples of marketing innovation, Betamax and Microsoft, and suggests that the cases actually offer an unconventional lesson about risk/reward. To illustrate best practice he examines the case of the Johnson & Johnson Development Corporation.FindingsCompanies that have achieved greatness have typically done so only at the cost of increased risk – something that has been ignored in much of established strategic thinking. The new frontier of value creation is therefore the management of risk through a portfolio of business models.Practical implicationsThis article describes a new method for managing strategic risk. It explains how to place critical strategic unknowns at the center of the strategic conversation.Originality/valueThe author introduces the concepts of Requisite Uncertainty and strategic flexibility as new ways of managing risk and suggests they be added to the management toolkit. Together, they represent a departure from how management has traditionally tackled the future's irreducible uncertainty.
Benchmarking efficiencies and strategies for resale operations of a charity organization
Authors: Joo Seong‐Jong , Stoeberl Philipp A. , Kwon Ik‐Whan G. 
Published: July 2007

PurposeThis paper aims to analyze and benchmark the operating efficiency of resale shops run by a charity organization and to suggest strategies for improved operations.Design/methodology/approachData envelopment analysis (DEA) was used to compare the operations of nine resale shops of a charity organization. Data include annual reports of the shops for two years.FindingsThe relatively efficient shops are located in the affluent communities, the eastern parts of the city. Accordingly, location is a major contributor to operating efficiency. For resource utilization, charges related to buildings are mostly underutilized among expenses, especially ownership costs and rents. DEA was found to be a useful approach for benchmarking resale operations.Research limitations/implicationsThis study is subject to the limitations of DEA, which measures relative technical efficiencies of decision‐making units. Results will vary according to data and decision‐making units included in the model.Originality/valueThe contributions of this study are found in the first attempt for benchmarking resale operations of a charity organization and in its strong practical application.
A randomized trial of bupropion and/or nicotine gum as maintenance treatment for preventing smoking relapse
Authors: Covey Lirio S. , Glassman Alexander H. , Jiang Huiping , Fried Jane , Masmela Jenny , LoDuca Catherine , Petkova Eva , Rodriguez Kristina 
Published: July 2007

ABSTRACTAim To investigate the efficacy of maintenance treatment with bupropion and/or nicotine gum for reducing smoking relapse.Design, setting and participants A 48‐week study was conducted at a university‐based smoking cessation clinic between February 2001 and October 2005. A total of 588 smokers received bupropion and nicotine patch in 8 weeks of open‐label treatment (OLT); 289 abstainers during the last 4 weeks of OLT were randomized in double‐blind placebo‐controlled fashion to one of four arms for 16 weeks of maintenance treatment (MT) followed by 24 weeks of non‐treatment follow‐up (NTFU).Intervention Bupropion (300 mg/day) and 2 mg nicotine gum, used alone or combined, and comparable placebo pill and placebo gum. Behavioral counseling at all visits.Outcome Time to relapse (TTR) from randomization. Relapse is defined as the first 7 consecutive days of smoking. Abstinence verified by carbon monoxide ≤ 8 parts per million.Findings TTR was longer with extended active treatments compared to placebo (median days to relapse: bupropion + placebo = 136, nicotine + placebo = 98, bupropion + nicotine = 90, double placebo = 71). Hazard ratios (HR) for relapse were statistically significant for bupropion + placebo versus double placebo during MT (HR = 0.59, 95% CI = 0.37–0.92) and to the end of NTFU (HR = 0.66, 95% CI = 0.42–0.96). However, bupropion's advantage dissipated upon stopping the drug. Gum use was low, preventing a valid assessment; but analysis restricted to gum users suggested a weak effect of extended nicotine gum.Conclusion Maintenance treatment with bupropion exerted a modest benefit for preventing smoking relapse; the optimum duration of bupropion treatment was unclear. Further research is needed to ascertain the merits of extended use of nicotine gum, other nicotine replacement agents and other treatments known to aid smokers for preventing relapse once abstinence is achieved.
Interactions of the Antizyme AtoC with Regulatory Elements of the
Escherichia coli atoDAEB
Operon
Authors: Matta Meropi K. , Lioliou Efthimia E. , Panagiotidis Cynthia H. , Kyriakidis Dimitrios A. , Panagiotidis Christos A. 
Published: July 2007

ABSTRACT

AtoC has a dual function as both an antizyme, the posttranslational inhibitor of polyamine biosynthetic enzymes, and the transcriptional regulator of genes involved in short-chain fatty acid catabolism (the
atoDAEB
operon). We have previously shown that AtoC is the response regulator of the AtoS-AtoC two-component signal transduction system that activates
atoDAEB
when
Escherichia coli
is exposed to acetoacetate. Here, we show that the same
cis
elements control both promoter inducibility and AtoC binding. Chromatin immunoprecipitation experiments confirmed the acetoacetate-inducible binding of AtoC to the predicted DNA region in vivo. DNase I protection footprinting analysis revealed that AtoC binds two 20-bp stretches, constituting an inverted palindrome, that are located at −146 to −107 relative to the transcription initiation site. Analyses of promoter mutants obtained by in vitro chemical mutagenesis of the
atoDAEB
promoter verified both the importance of AtoC binding for the inducibility of the promoter by acetoacetate and the σ
54
dependence of
atoDAEB
expression. The integration host factor was also identified as a critical component of the AtoC-mediated induction of
atoDAEB
.
Spherical shells in inelastic collision with a rigid wall—tentative analysis and recent quasi-static testing
Authors: Kinkead A N , Jennings A , Newell J , Leinster J C 
Published: July 2007

This paper considers the crushing which occurs in a spherical shell made of ductile material on striking a rigid wall. A static analysis is developed which allows for strain hardening, while for relatively low impact velocities, such as to permit the effect of inertia to be neglected, strain rate sensitivity is allowed for in an empirical manner. The analysis presented is applicable to spherical shells with a mean radius to thickness ratio exceeding seven, constructed in ductile material obeying a simple power law work hardening relationship. The deformation is assumed to occur in two phases. In the first phase a local flattening of the shell in contact with the rigid wall occurs, while in the second, an axisymmetric dimpling of the previously flattened portion takes place. Other workers have discovered that at radius to thickness ratios exceeding one hundred, a third mode of behaviour takes place when a number of non-axisymmetric nodes can be formed. The analysis in this paper, however, is only applicable to lower ratios when the crushing deformation, although reaching a value of half the radius, remains axisymmetric, as is borne out in all the experimental results examined for correlation. A number of assumptions and simplifications are made, all of which are clearly stated below. Reference is made to earlier papers on this subject and a comparison is made of correlations by such earlier work and by the present analysis in respect of a group of quasi-static tests carried out by the Civil Engineering Department of the Queen's University of Belfast under a Leverhulme Trust fellowship funding: this is described in detail in Appendix 1. The result of a moderate velocity impact test on a spherical shell of 625 mm diameter is utilized to examine the correlation given by the present analysis taking strain rate effect into account. Note: the first author was mainly concerned with the analysis, while the co-authors carried out the experimental work detailed in Appendix 1.
An experimental investigation of dynamic crack propagation
Authors: Hyde T H , Yaghi A 
Published: July 2007

Burst tests have been performed on closed-ended thin wall tubes with axially aligned, external, semicircular, crack-like flaws. The tubes were made of Araldite CT200 with HT907 hardener. Dynamic crack propagation rates between 0.14c1 and 0.30c1 were measured, c1 being the velocity of longitudinal waves in the walls of the tubes. The fracture surfaces exhibited a smooth mirror-like appearance near the crack initiation site. This was followed by a mist region and then a hackle region. The roughness in the hackle region becomes progressively greater with distance from the initiation site and crack branching can eventually occur. The KID/KIC (where KID is the applied dynamic stress intensity factor and KIC is the plane strain fracture toughness) value at which the hackle region begins is about 3.34 and the KID/KIC value at which branching begins is about 8.75. Previously reported work only contains results for KID/KIC up to about 5. The present work contains results for KID/KIC up to about 14, which correlate with previous work for KID/KIC values less than about 4. However, previous work has indicated that a unique relationship may exist between v/c1 and KID/KIC. The present work indicates that although this is a good approximation, a systematic variation with load (pressure in this case) has been detected.
Some comments on the initialization of exponential smoothing
Authors: Ledolter Johannes , Abraham Bovas 
Published: July 2007

AbstractIt is shown that the traditional choice for the initial smoothed statistics in general exponential smoothing leads to the same forecasts as the equivalent ARIMA model, provided that one uses zero starting values for the initial shocks. In addition, an initialization which uses ‘backforecasts’ as initial smoothed statistics is considered, and its relationship to unconditional least squares is explored.
Administrative change and the Arab manager
Authors: Jreisat Jamil E. 
Published: July 2007

AbstractThe success of developing countries in fostering administrative change has not been commensurate with their intensive efforts and investments. Causes and effect of the slow progress of change elude and even bewilder scholars and practitioners alike. Based on experiences from the Arab world, this study proposes modifications in organizational processes and behaviour to balance the traditional, one‐directional policies of administrative change. When change originates outside the organization or at its very top, and is communicated downwards by decree or edict, three important elements are inevitably absent: employee involvement, effective incentive systems, and appropriate methods of evaluation. Public managers in various Arab countries express preference for jobs that allow them, as managers, to utilize their knowledge and skills, and which do not reduce them to mere executioners of higher commands. Comparing this group with a similar group of American managers reveals managerial characteristics of particular pertinence to administrative change.
The nature of managerial work in the public sector: An African perspective
Authors: Vengroff Richard , Belhaj Mohamed , Ndiaye Momar 
Published: July 2007

AbstractIt has been asserted too often that the development of non‐western countries—those of Africa, in particular—is highly dependent upon their assimilation of western management techniques. Yet, the applicability of western management techniques to a non‐western cultural milieu remains the subject of debate in the public administration and management literature. Much of the management development literature since the mid 70s has dealt with the replicability of Mintzberg's partition of the nature and contents of the manager's activities in diverse western work settings, in the US primarily. Few attempts have been undertaken to test Mintzberg's findings in non‐western settings. In this article, the authors attempt to partially fill this gap in the literature. More specifically, the authors investigate the degrees to which the management roles identified in the US can be applied generically to the public sector in the African context. The findings indicate that perceptions of management roles at the macro level are highly consistent across cultural boundaries. Significant differences, derived primarily from the historic experience of colonial administration and the contingent micro level impact are also noted. The implications of these findings for the design and implementation of management training programmes in Africa are explored.
Urban government and market reforms in China
Authors: White Gordon 
Published: July 2007

AbstractChinese reformers wish through their economic programme to create a new form of developmental state in China and a new relationship between state and economy. This paper examines these issues through a study of the impact of Chinese economic reforms on the structure and behaviour of local government, focusing on urban government at the district level. It looks at three aspects of the issue—the trend towards financial decentralization, institutional changes in district administration and changes in the relationship between local government and the urban economy. It concludes (contrary to arguments which regard bureaucratic response to the reforms as one of pure inertia and obstruction) that urban local government has changed in several major ways, the most obvious being a trend towards institutional expansion and proliferation. From the point of view of the reform process, some institutional changes have been positive, others negative, resulting in a ‘dualistic’ state which contains elements of both old and new forms of developmental state. There is a need for systematic analysis of the specific future needs and evolution of China's urban government which would guide a process of politico‐administrative reform comparable to the current economic reform.
The impact of decentralization on health workforce development in Papua New Guinea
Authors: Riitta‐Liisa  , Kolehmainen‐Aitken  
Published: July 2007

AbstractPapua New Guinea decentralized a wide range of health functions to provincial governments between 1977 and 1983. The national Department of Health (DOH) was given no role in provincial budget and staffing decisions, and the national health budget was fragmented into the health components of provincial budgets. The impact of decentralization on health workforce development was particularly severe and largely unforeseen. Many difficulties were inherent in the manner in which decentralization regulations structured power relationships. Others arose as a result of the administrative confusion and inflamed relationships that accompanied the forceful transfer of power from a very reluctant national DOH to the provinces. Even though policy formulation and planning were retained as national functions, decentralization hampered their effective execution. Human resource data bases deteriorated, responsibility for planning became confused, and the ability of the DOH to implement its planning decisions was compromised. In reality, health workforce planning was carried out by the Departments of Finance and Planning, and Personnel Management through the annual budgetary process of provincial financial limits and staff ceilings, without any attempt to assess health service needs, either in the country as a whole or between the provinces. Decentralization brought a need for new management skills, and it complicated administrative relationships between training institutions and the provinces. The Papua New Guinea experience has shown that in a decentralized health service, there is a great potential for conflict between national goals and the aspirations of individual provinces. To achieve an equitable, appropriate and effective staffing of services, standards must be formulated as the basis for planning and conflict resolution. Effective linkages between central government departments and between the national and provincial health authorities must be developed, and management and technical skills of health managers improved.