bluuebunny/crossref_metadata_2025 huggingface dataset:
Electron paramagnetic resonance studies of membrane fluidity in ozone‐treated erythrocytes and liposomes
Authors: Wróbel Anna , Gomułkiewicz Jan
Published: July 2007

Doxyl stearate spin probes which differed in the attachment of the nitroxide free radical to the fatty acid have been used to study membrane fluidity in ozone‐treated bovine erythrocytes and liposomes. Analysis of EPR spectra of spin labels incorporated into lipid bilayer of the erythrocyte membranes indicates an increase in the mobility and decrease in the order of membrane lipids. In isolated erythrocyte membranes (ghosts) the most significant changes were observed for 16‐doxylstearic acid. In intact erythrocytes statistically significant were differences for 5‐doxylstearic acid. The effect of ozone on liposomes prepared from a lipid extract of erythrocyte lipids was marked in the membrane microenvironment sampled by all spin probes. Ozone apparently leads to alterations of membrane dynamics and structure but does not cause increased rigidity of the membrane.
Steroid sulfatase activity in leukocytes: a comparative study in 45,X; 46,Xi(Xq) and carriers of steroid sulfatase deficiency
Authors: Miranda‐Duarte Antonio , Valdés‐Flores Margarita , Miranda‐Zamora Rodrigo , Díaz‐Zagoya Juan C. , Kofman‐Alfaro Susana H. , Cuevas‐Covarrubias Sergio A.
Published: July 2007

The enzyme steroid sulfatase (STS) hydrolyses 3‐beta‐hydroxysteroid sulfates. The female‐male STS activity ratio is 1.04‐1.7:1 in several cell lines in adults and reaches 2…n1 in prepubertal subjects. In fibroblasts, STS values in X‐chromosome abnormalities show a partial positive correlation according to the number of X‐chromosomes. X‐linked ichthyosis (XLI) carriers, with only one copy of the STS gene, present lower STS levels than normal controls. This study analyzes the STS activity in leukocytes of 46,Xi(Xq); 45,X; XLI carriers and normal controls using 7‐[3H]‐dehydroepiandrosterone sulfate as substrate. X‐monosomy (1.07±0.18 pmol/mg protein/h), Xq isochromosome (1.02±0.12 pmol/mg protein/h) and normal females (1.03±0.11 pmol/mg protein/h) had similar STS values (p>0.05). XLI‐carriers and males showed the lowest STS levels (0.34±0.04 pmol/mg protein/h, p<0.001 and 0.82±0.14 pmol/mg protein/h, p<0.05, respectively). Female‐male STS activity ratio in leukocytes was 1.3…n1. These data indicate that a complex mechanism regulates the STS expression depending on each type of cell line.
Characterization of the carboxyl terminal‐truncated endothelin B receptor coexpressed with G protein‐coupled receptor kinase 2
Authors: Shibasaki Tadao , Moroi Kayoko , Nishiyama Mariko , Zhou Jing , Sakamoto Aiji , Masaki Tomoh , Ito Kazumitsu , Haga Tatsuya , Kimura Sadao
Published: July 2007

The role of phosphorylation of the C‐terminal tail of endothelin B receptor (ETbR) in agonist‐induced desensitization was investigated, using a mutant lacking C‐terminal 40 amino acids (Δ40 ETbR). In cells expressing the wild type or Δ40 ETbR, ET‐1 caused rapid desensitization of calcium responses. The wild type ETbR was phosphorylated by biotinylated ET‐1, and the phosphorylation was markedly enhanced by coexpression with G protein‐coupled receptor kinase 2 (GRK2). However, Δ40 ETbR was not phosphorylated regardless of coexpression with GRK2. On the other hand, ET‐1‐induced IP3 formation in these cells was decreased by coexpression with GRK2 or catalytically inactive Lys220Arg GRK2 to the similar extent. The present study demonstrates the presence of phosphorylation‐independent desensitization mechanism in Δ40 ETbR and suggests that GRK2 might play a role other than that as a kinase.
Characterization of the human CR1 gene promoter
Authors: Kim Jae Hyun , Lee Sooyeon , Choe Soo Young
Published: July 2007

The human CR1 is a single chain membrane glycoprotein that is a member of the group of regulators of the complement activation system. In order to clarify the regulatory mechanisms of human CR1 gene expression, the 5′‐flanking region of the human CR1 gene was isolated and its promoter was characterized. The CR1 expression was found to be transcriptionally up‐regulated in HL60 cells by stimulation with DMSO. The cloned CR1 gene promoter was sequenced and computer analyzed. The potential promoter region lacks a distinct TATA box sequence. The transcription initiation site was determined by primer extension and several possible regulatory elements for transcription were found in the promoter region.
Kinetic properties of ATP‐dependent phosphofructokinase from grapefruit juice sacs: effect of tca cycle intermediates
Authors: Van Praag Esther , Zehavi Uri , Goren Raphael
Published: July 2007

Grapefruit juice sac ATP‐PFK was studied kinetically for its substrates ATP and Fru‐6‐P at pH = 7.5. The Km for ATP is equal to 39.8 ± 4.6 μM. ATP becomes inhibitory at concentrations above 80 μM. The Km for ATP is not affected by the addition of citrate (10 mM). For Fru‐6‐P, the saturation curve is sigmoidal, with an S0.5 equal to 0.17 ± 0.03 mM, in the presence of Mg++ (2.5 mM) and ATP (1 mM). ATP‐PFK shows a negative cooperativity at lower concentrations of Fru‐6‐P (h = 0.5), while higher concentrations of the substrate induce a positive cooperation (h = 1.5). The presence of citrate affects the S0.5 affinity value, but not the Vmax. The presence of citrate (10 mM) removes the cooperative effect at higher concentrations of the substrate, as h = 1.0. A theoretical Ki for citrate was calculated and equals 1.30 mM.
Synthetic insulin fragment with insulin‐like biological activity
Authors: Prozorovskiy V. N. , Maksimova E. M. , Alekseeva A. E. , Grebenschikova O. G. , Abakumova O.Yu. , Kutsenko N. G. , Ivanov A. S. , Kniazhev V. N. , Archakov A. I.
Published: July 2007

An insulin fragment, representing the C‐terminal functionally important site of its molecule and responsible for receptor binding, was synthesized. The fragment consists of two peptides: a dipeptide (A 20‐21) and an octapeptide (B 19‐26), linked with a disulfide bond (A20‐B19). The biological activity of the newly synthesized fragment relative to insulin was assayed for the influence on glycogenesis and for the ability to stimulate glucose uptake. Comparative tests for the biological activity of the synthesized fragment and of the intact hormone allowed us to conclude that the fragment has insulin‐like properties.
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

The 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

A 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

Superoxide (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

trans‐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

The 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

Alkyl‐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

Purpose

The 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/approach

The 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.

Findings

Companies 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 implications

This 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/value

The 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

Purpose

This 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/approach

Data 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.

Findings

The 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/implications

This 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/value

The 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

Aim 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.
Attaining a Homogeneous Microstructure of a ZnO‐Based Multilayer Varistor by Constrained Sintering
Authors: Lee Wen‐His , Chen Wei‐Ting , Su Chi‐Yi
Published: July 2007

The performance of a ZnO‐based multilayer varistor (MLV) is affected strongly by the homogeneity of its microstructure. In this study, a homogeneous microstructure of ZnO‐based MLV was attained by using constrained sintering when nonreactive borosilicate glass +90 wt% alumina (Al2O3) was used as a constraining layer laminated on both sides of the multilayer ZnO‐based MLV. The mean grain size and the distribution of grain size of ZnO‐based MLVs are both reduced because by constrained sintering, an in‐plane tensile stress results from constrained sintering in the x–y plane of a multilayer device, which could modify the densification rate of the dielectric materials.
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

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
.
Activation of apoptotic processes during transition from hypertrophy to heart failure in guinea pigs
Authors: Sharma A. K. , Dhingra S. , Khaper N. , Singal P. K.
Published: July 2007

Changes in oxidative stress and apoptotic process were studied during the progression of a compensated hypertrophy to a decompensated heart failure in guinea pigs. Banding of the ascending aorta resulted in heart hypertrophy. At 10 wk, ventricle-to-body weight ratio and thickness of the interventricular septum as well as the left ventricular wall were increased significantly. Although fractional shortening and ejection fraction were decreased, there were no signs of heart failure. Furthermore, there was no increase in wet-to-dry weight ratios for the lungs and liver at this stage. However, at 20 wk, heart failure was characterized by a significant depression in heart function as indicated by a decrease in fractional shortening, and ejection fraction and a lesser increase in wall thickness from diastole to systole. Animals also showed clinical signs of heart failure, and the wet-to-dry weight ratios of the lungs and liver were significantly higher. Cardiomyocyte oxidative stress was significantly higher in the 20-wk aortic-banded group. The ratio of Bax to Bcl-xl showed an increase at 10 wk, and there was a further increase at 20 wk. Mitochondrial membrane potential in the aortic-banded animals was significantly decreased at 10 and 20 wk. Cytochrome c levels were higher in the cytosol compared with the mitochondria, leading to a considerable increase in the expression of p17 subunit of caspase-3. At 20 wk, both early and late stages of apoptosis were observed in isolated cardiomyocytes. It is suggested that an increase in oxidative stress initiates mitochondrial death pathway during the hypertrophic stage, leading to apoptosis and heart failure at a later stage.
Evaluation of yield function including effects of third stress invariant and initial anisotropy
Authors: Takeda T , Nasu Y
Published: July 2007

By means of combining Drucker's yield function with Hill's quadratic yield function, the anisotropic yield function of the sixth degree is proposed. It is able to include the effects of the third deviatoric stress invariant and initial anisotropy. The experimental evaluation is made on thin-walled cylindrical specimens of mild steel (in the fully annealed condition and the stress-relief annealed condition after a tensile pre-strain) and 2024 aluminum alloy (in the -0 and -T6 tempered conditions). By applying proportional combined loadings of axial load, internal pressure, and torsion to the specimens, a change of yield stress with a rotation of the principal stress axes and a difference between the directions of the principal stress and principal strain increment are examined Under tension–internal pressure and tension–torsion, the yield surfaces and strain behaviour are determined. The fully annealed steel is almost isotropic for yielding although it reveals the effect of the third deviatoric stress invariant. The stress-relief annealed steel and the 2024–0 and -T6 aluminum alloys exhibit axi-symmetric anisotropy. All of the yield surfaces can be expressed precisely by the proposed yield function. In addition, the normality rule is obeyed in strain behaviour.
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

It 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

The 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

It 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

Chinese 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

Papua 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.
Participatory environmental management: Contradiction of process, project and bureaucracy in the Himalayan foothills
Authors: Shepherd Andrew
Published: July 2007

Using comparative Asian experience of organizational change, this article analyses the experience of an Indian organization responsible for environmental management in the Himalayan foothills of Uttar Pradesh (UP) in moving from a standard Indian public sector approach to rural development and environmental management, to a new participatory approach. Successive World Bank funded watershed management projects in the Himalayan foothills were widely held not to have achieved and sustained their full potential in the past, largely due to an absence of effective local management of assets after the projects' end. On the other hand communities and groups have shown on a small scale a capacity to manage resources in a sustainable way. The Government of Uttar Pradesh's (UP) European Union (EU) funded Doon Valley Project has been through a first phase in which a participatory method of village level planning has been initiated. The article addresses the required changes and constraints involved in this first step of transformation. These include issues to do with organizational structure and procedures, training, gender and other social issues, and the dynamics of organizational change. The implications of a participatory approach are far reaching. The ‘off the shelf’ schemes that Government has offered to individuals, groups and communities in all watershed management as well as other rural development programmes are challenged both by the specificities of the Himalayan environment, and by the adoption of a genuinely participatory approach. Allowing people to decide how they will manage their hillsides requires an ability to facilitate that process. Facilitators need to have the flexibility and creativity to offer a variety of technical and managerial possibilities such that individuals, groups and communities can choose what suits them best. Constraints derive partly from the Government's set procedures and schemes in rural development, and from its advocacy of particular well worn technology packages. Constraints also derive from the way in which the whole project has been handled by Government and the Commission of the European Union from the beginning, and from the way in which technical assistance has been organized. It is important that governments and donors learn from such experiences so that future participatory environmental management work can have a greater chance of success.
Quantum Mechanics of H‐Atom from Path Integrals
Authors: Duru I. H. , Kleinert H.
Published: July 2007

The quantum mechanical Coulomb problem in two and three dimensions is solved completely in terms of path integrals. We derive the integral representations for the Green's functions in configuration space and recover the wave functions from factorized residues.
Short‐run statistical process control: Q‐chart enhancements and alternative methods
Authors: Castillo Enrique Del , Montgomery Douglas C.
Published: July 2007

In processes where the length of the production run is short, data to estimate the process parameters and control limits may not be available prior to the start of production, and because of the short run time, traditional methods for establishing control charts cannot be easily applied. Recently, Q charts have been proposed to address this problem. We study the average run length (ARL) of Q charts for a normally distributed variable assuming that a sustained shift occurs in the quality characteristic. It is shown that in some cases Q charts do not exhibit adequate ARL performance. Modifications that enhance the ARL properties of Q charts are presented. Some alternatives to Q charts are also discussed. For the case of a known process target two alternative methods are presented: an exponentially weighted moving average (EWMA) method and an adaptive Kalman filtering method. It is shown that both methods have better ARL performance than Q charts for that case. For the case of both process parameters unknown, an adaptive Kalman filtering method used with a tracking signal provides an ARL performance that improves as better estimates of the process mean and variance are given. A practical example illustrates the tracking signal method for the case when the process parameters are unknown.
Local reconstruction in computed tomography of diffraction enhanced imaging
Authors: Huang Zhi-Feng , Zhang Li , Kang Ke-Jun , Chen Zhi-Qiang , Zhu Pei-Ping , Yuan Qing-Xi , Huang Wan-Xia
Published: July 2007

Computed tomography of diffraction enhanced imaging (DEI-CT) based on synchrotron radiation source has extremely high sensitivity of weakly absorbing low-Z samples in medical and biological fields. The authors propose a modified backprojection filtration(BPF)-type algorithm based on PI-line segments to reconstruct region of interest from truncated refraction-angle projection data in DEI-CT. The distribution of refractive index decrement in the sample can be directly estimated from its reconstruction images, which has been proved by experiments at the Beijing Synchrotron Radiation Facility. The algorithm paves the way for local reconstruction of large-size samples by the use of DEI-CT with small field of view based on synchrotron radiation source.
Europeanization and Euroscepticism: Experiences from Poland and the Czech Republic
Authors: Riishøj Søren
Published: July 2007

National identity was already the object of scholarly studies by the 1950s and 1960s, e.g. by analysts such as Karl Deutsch and Ernest Hass, to a great extent inspired by the start of European integration and German and French reconciliation. One of the crucial questions has been (and still is) to what extent national identity constitutes a barrier to Europeanization and integration, and to what extent overlapping multiple identities can co-exist.
Can Jealousy be Reduced to a Science? Politics and Economics in Hume's Essays
Authors: Mankin Robert
Published: July 2007

Today we tend to read David Hume's Essays, Moral, Political and Literary in the 1777 edition, a two-part collection dating essentially from the early 1740s and then again from the early 1750s, as revised continually by the author until his death in the year of the American Declaration of Independence. Although this is better than reading the essays in anthologies, even the best text that we have ever had (the Liberty Fund's) is a compendious final version rather than a critical edition, one that would lead us not only into what the essays are but also what they were about. Hume's revisions and afterthoughts are, for the most part, duly noted, but never put into perspective; and his intentions at the outset are underplayed or simply ignored (Hume 1777). Yet it would be a great help to have more clarity on this desire for changes, for it is remarkable in Hume's career. When, very shortly after publication in 1738, he came to feel reservations about the Treatise of Human Nature, he simply scrapped it and wrote new versions of his philosophy. With the Essays, in contrast, he was more tempted than with any other work published in his lifetime, and more chronically tempted, to revise and adapt his thoughts and then resubmit them to the public. With these labors he was not saving or preparing them for posterity so much as constantly adjusting them to the present as he understood it. This is the kind of evidence that might be cited for a recent claim that the Essays are “contemporary history” (Pocock 1999, vol. ii., p.177ff.).
Preferential Binding of Leukocytes to the Endothelial Junction Region in Venules In Situ
Authors: WOJCIECHOWSKI JOEL C. , SARELIUS INGRID H.
Published: July 2007

Objective: To determine whether leukocytes show a preference to firmly adhere to the endothelium near the endothelial cell (EC) junction in their native environment, i.e., blood‐perfused venules in situ.

Methods: Intravital confocal microscopy was used to determine the positions of firmly adherent leukocytes with respect to EC junctions in cremaster muscle venules in anesthetized mice. EC area and EC junction locations were identified using immunofluorescent labeling of platelet–endothelial cell adhesion molecule‐1 (PECAM‐1), an endothelial junction protein. Leukocytes were identified using transillumination through the same optical path.

Results: Seventy‐five percent of firmly adherent leukocytes overlapped an EC junction (the average distance to the nearest EC junction was 2.4 ± 0.1 μ m, n = 263). This distance was less in smaller diameter venules, hence the percentage of adherent leukocytes that overlapped an endothelial junction was larger. EC shape and size varied with venular diameter: in smaller venules (30–49 μ m diameter), ECs had significantly less area (316 ± 19 μ m2) and were narrower (12.5 ± 0.4 μ m) than in larger (70–89 μ m diameter) venules, which had 614 ± 28 μ m2 area and 17.8 ± 0.5 μ m width, respectively (p < .001). Furthermore, the majority (73.0%) of firmly adherent leukocytes crawled an average distance of 29.4 ± 2.8 μ m at a mean intralumenal migration velocity of 7.6 ± 0.4 μ m/min before undergoing transmigration or detaching and reentering the free fluid stream.

Conclusions: Most adherent leukocytes in blood‐perfused venules are located at or near EC junctions. This is primarily due to the size and shape of venular ECs. Further, most leukocytes that appear to be adherent are in fact motile, and migrate a significant distance along the lumenal wall. The authors speculate that this reflects movement to those EC junctional regions that support transendothelial migration.
Quenching of singlet molecular oxygen by carnosine and related antioxidants. Monitoring 1270‐nm phosphorescence in aqueous media
Authors: Egorov Sergei Yu. , Kurella Ekaterina G. , Boldyrev Alexander A. , Krasnovsky Alexander A.
Published: July 2007

In order to elucidate the biochemical roles of imidazol‐containing dipeptides, we have studied quenching of singlet molecular oxygen (1O2) by carnosine (β‐alanyl‐L‐histidine), its structural components (L‐histidine, imidazole, and β‐alanine), and related natural free‐radical scavengers ‐ L‐anserine (β‐alanyl‐l‐methyl‐histidine), ergothioneine (2‐thiol‐ L‐histidine‐betaine), and taurine (2‐aminoethanesulfonic acid) in aqueous (D2O, pD 7) solutions by using monitoring of 1O2‐phosphorescence (1270‐nm). The rate constants of 1O2 quenching (Kq) by carnosine, anserine, and ergothioneine were shown to be similar [(3±1)×107 M‐1s‐1]. Their values resembled those of free L‐histidine [Kq=(4±1)×107 M‐1s‐1] and imidazole [Kq=(2±1)×107 M‐1s‐1]. Non‐aromatic amino acids ‐ taurine and β‐alanine ‐ showed very low quenching activities (Kq<3×103 M‐1c‐1). The Kq values did not correlate with the literature data on abilities of the tested compounds to stimulate muscle working capacities and inhibit myeloperoxidase‐catalyzed oxygenation. Thus, the dipeptides can be used as potent water‐soluble protectors against 102 attack whereas their natural biochemical functions are most probably determined by the processes of different nature.
Gastric mucosal apoptosis induced by ethanol: effect of antiulcer agents
Authors: Piotrowski J. , Piotrowski E. , Skrodzka D. , Slomiany A. , Slomiany B. L.
Published: July 2007

In this study, we investigated gastric epithelial cells' apoptosis and tumor necrosis factor‐α (TNF‐α) expression with ethanol‐induced mucosal injury, and the effect of antiulcer agents on this process. Rats received intragastric pretreatment with the agent or vehicle followed 1h later by ethanol, and after 30 min the gastric mucosa was assessed for TNF‐α and apoptosis. In the absence of antiulcer agents, ethanol caused extensive mucosal lesions accompanied by a 9.5‐fold enhancement in apoptosis and a 2.5‐fold increase in TNF‐α. Pretreatment with omeprazole evoked a 54% reduction in TNF‐α, but had no effect on ethanol‐induced mucosal damage or apoptosis, the sucralfate reduced the extent of mucosal damage by 95%, apoptosis by 39% and TNF‐α by 52%, while ebrotidine not only prevented mucosal injury and rise in TNF‐α, but also caused a 70% reduction in epithelial cells' apoptosis. The results demonstrate that ethanol‐induced gastric epithelial cells apoptosis triggered by the enhancement in mucosal TNF‐α is efficiently counteracted by ebrotidine.
A six‐domain structural model for Escherichia coli translation initiation factor IF2. Characterisation of twelve surface epitopes
Authors: Mortensen Kim Kusk , Kildsgaard Jens , Moreno Juan Manuel Palacios , de Søren A. , Steffensen A. , Egebjerg Janni , Sperling‐Petersen Hans Uffe
Published: July 2007

The Escherichia coli translation initiation factor IF2 is a 97 kDa protein which interacts with the initiator fMet‐tRNAf/Met, GTP and the ribosomal subunits during initiation of protein biosynthesis. For structural and functional investigations of the factor, we have raised and characterised monoclonal antibodies against E. coli IF2. Twelve epitopes have been localised at the surface of the protein molecule by three different methods: Interactions of the monoclonal antibodies with nested deletion mutants of IF2, comparison of the relative location of the epitopes in a competition immunoassay and cross‐reactivity analyses of the monoclonal antibodies towards IF2 from Salmonella typhimurium, Klebsiella oxytoca, Enterobacter cloacae, Proteus vulgaris, and Bacillus stearothermophilus. These data are combined with predicted secondary structure and discussed in relation to a six‐domain structural model for IF2. The model describes IF2 as a slightly elongated molecule with a structurally compact C‐terminal domain, a well‐conserved central GTP‐binding domain, and a highly charged, solvent exposed N‐terminal with protruding α‐helical structures.