bluuebunny/crossref_metadata_2025 huggingface dataset:
The impact of driver distraction on road safety: results from a representative survey in two Australian states
Authors: McEvoy S P , Stevenson M R , Woodward M
Published: August 2006

Objective:To quantify the prevalence and effects of distracting activities while driving.

Design:Cross sectional driver survey.

Setting:New South Wales and Western Australia, Australia.

Participants:1347 licensed drivers aged between 18 and 65 years. Data were weighted to reflect the corresponding driving population.

Main outcome measures:Prevalence of distracting activities while driving; perceived risks and adverse outcomes due to distractions.

Results:The most common distracting activities during the most recent driving trip were lack of concentration (weighted percentage (standard error, SE) 71.8% (1.4%) of drivers); adjusting in-vehicle equipment (68.7% (1.5%)); outside people, objects or events (57.8% (1.6%)); and talking to passengers (39.8% (1.6%)). On average, a driver engaged in a distracting activity once every six minutes. One in five crashes (21%) during the last three years, involving one in 20 drivers (5.0% (0.7%)), was attributed to driver distraction based on self-report. In the population under study, this equated to 242,188 (SE 34,417) drivers. Younger drivers (18–30 years) were significantly more likely to report distracting activities, to perceive distracting activities as less dangerous, and to have crashed as a result.

Conclusions:Distracting activities while driving are common and can result in driving errors. Driver distraction is an important cause of crashes. Further research is needed to estimate the risk conferred by different distracting activities and the circumstances during which activities pose greatest risk. These results suggest that a strategy to minimize distracting activities while driving, with a focus on young drivers, is indicated.
Increased reach and effectiveness of a statewide tobacco quitline after the addition of access to free nicotine replacement therapy
Authors: An Lawrence C , Schillo Barbara A , Kavanaugh Annette M , Lachter Randi B , Luxenberg Michael G , Wendling Ann H , Joseph Anne M
Published: August 2006

Background:Tobacco users receiving behavioural and pharmacological assistance are more likely to quit. Although telephone quitlines provide population access to counselling, few offer pharmacotherapy.

Objective:To assess change in cessation rates and programme impact after the addition of free nicotine replacement therapy (NRT) to statewide quitline services.

Design, setting, participants:An observational study of cohorts of callers to the Minnesota QUITPLANSMHelpline before (n  =  380) and after (n  =  373) the addition of access to free NRT.

Intervention:Mailing of NRT (patch or gum) to callers enrolling in multi-session counselling.

Main outcome measure:Thirty-day abstinence six months after programme registration.

Results:The number of callers increased from 155 (SD 75) to 679 (180) per month pre-NRT to post-NRT (difference 524, 95% confidence interval (CI) 323 to 725). Post-NRT, the proportion of callers enrolling in multi-session counselling (23.4%v90.1%, difference 66.6%, 95% CI 60.8% to 71.6%) and using pharmacotherapy (46.8%v86.8%, difference 40.0%, 95% CI 31.3% to 47.9%) increased. Thirty-day abstinence at six months increased from 10.0% pre-NRT to 18.2% post-NRT (difference 8.2%, 95% CI 3.1% to 13.4%). Post-NRT the average number of new ex-smokers per month among registrants increased from 15.5 to 123.6 (difference 108.1, 95% CI 61.1 to 155.0). The cost per quit pre-NRT was $1362 (SD $207). The cost per quit post-NRT was $1934 ($215) suggesting a possible increase in cost per quit (difference $572, 95% CI −$12 to $1157).

Conclusion:The addition of free NRT to a state quitline is followed by increases in participation and abstinence rates resulting in an eightfold increase in programme impact. These findings support the addition of access to pharmacological therapy as part of state quitline services.
Smoke-free laws and secondhand smoke exposure in US non-smoking adults, 1999–2002
Authors: Pickett Melanie S , Schober Susan E , Brody Debra J , Curtin Lester R , Giovino Gary A
Published: August 2006

Objectives:To investigate the relationship between smoke-free law coverage and secondhand smoke (SHS) exposure in the United States non-smoking adult population.

Design:We used data from the 1999–2002 National Health and Nutrition Examination Survey, a cross-sectional survey designed to monitor the health and nutritional status of the US population. Serum cotinine levels were available for 5866 non-smoking adults from 57 survey locations. Each location was categorised into one of three groups indicating extensive, limited, and no coverage by a smoke-free law.

Main outcome measures:The proportion of adults with SHS exposure, defined as having serum cotinine levels ⩾ 0.05 ng/ml.

Results:Among non-smoking adults living in counties with extensive smoke-free law coverage, 12.5% were exposed to SHS, compared with 35.1% with limited coverage, and 45.9% with no law. Adjusting for confounders, men and women residing in counties with extensive coverage had 0.10 (95% confidence interval (CI) 0.06 to 0.16) and 0.19 (95% CI 0.11 to 0.34) times the odds of SHS exposure compared to those residing in counties without a smoke-free law.

Conclusions:These results support the scientific evidence suggesting that smoke-free laws are an effective strategy for reducing SHS exposure.
What contributed to the major decline in per capita cigarette consumption during California’s comprehensive tobacco control programme?
Authors: Gilpin Elizabeth A , Messer Karen , White Martha M , Pierce John P
Published: August 2006

Objectives:California experienced a notable decline in per capita cigarette consumption during its comprehensive tobacco control programme. This study examines what proportion of the decline occurred from: (1) fewer ever smokers in the population, (2) more ever smokers quitting, and (3) current smokers smoking less.

Design, subjects:Per capita cigarette consumption computed from cigarette sales and from adult respondents to the large, cross-sectional, population-based California Tobacco Surveys of 1990 (n  =  24 296), 1996 (n  =  18 616) and 2002 (n  =  20 525) were examined for similar trends.

Main outcome measure:Changes (period 1: 1990–1996; period 2: 1996–2002) in per capita cigarette consumption from self-reported survey data were partitioned for the entire population and for demographic subgroups into the three components mentioned above.

Results:In periods 1 and 2, most of the decline in per capita cigarette consumption for the population as a whole was from current smokers smoking less followed by a reduction in ever smokers. The decline from smokers smoking less was particularly evident among young adults (18–29 years) in period 1. While the portion of the decline due to quitting in the entire population in period 1 was negligible, in period 2 it accounted for 22% of the total per capita decline. The decline from quitting in period 2 was mostly observed among women.

Conclusions:Rather than near-term benefits from smokers quitting, population health benefits from reduced per capita cigarette consumption will likely occur over the longer term from fewer people becoming ever smokers, and more less-addicted smokers eventually quitting successfully.
An ethnographic study of tobacco control in hospital settings
Authors: Schultz Annette S H , Bottorff Joan L , Johnson Joy L
Published: August 2006

Background:Tobacco control in hospital settings is characterised by a focus on protection strategies and an increasing expectation that health practitioners provide cessation support to patients. While practitioners claim to have positive attitudes toward supporting patient cessation efforts, missed opportunities are the practice norm.

Objective:To study hospital workplace culture relevant to tobacco use and control as part of a mixed-methods research project that investigated hospital-based registered nurses’ integration of cessation interventions.

Design:The study was conducted at two hospitals situated in British Columbia, Canada. Data collection included 135 hours of field work including observations of ward activities and designated smoking areas, 85 unstructured conversations with nurses, and the collection of patient-care documents on 16 adult in-patient wards.

Results:The findings demonstrate that protection strategies (for example, smoking restrictions) were relatively well integrated into organisational culture and practice activities but the same was not true for cessation strategies. An analysis of resources and documentation relevant to tobacco revealed an absence of support for addressing tobacco use and cessation. Nurses framed patients’ tobacco use as a relational issue, a risk to patient safety, and a burden. Furthermore, conversations revealed that nurses tended to possess only a vague awareness of nicotine dependence.

Conclusion:Overcoming challenges to extending tobacco control within hospitals could be enhanced by emphasising the value of addressing patients’ tobacco use, raising awareness of nicotine dependence, and improving the availability of resources to address addiction issues.
Nicotine replacement therapy for long-term smoking cessation: a meta-analysis
Authors: Etter Jean-François , Stapleton John A
Published: August 2006

Objective:To assess if the effect of a single treatment episode with nicotine replacement therapy (NRT) enhances smoking cessation over many years.

Data sources:Meta-analysis of all randomised controlled trials of NRT with final follow-up more than one year after the start of treatment. Twelve eligible trials were identified, all placebo-controlled, having final follow-ups ranging from 2–8 years. All had earlier follow-ups at 12 months. They comprised 2408 active and 2384 placebo treatment participants.

Data synthesis:The odds ratio (OR) in favour of NRT at final follow-up was 1.99 (95% confidence interval (CI) 1.50 to 2.64). There was no evidence that the effect varied according to length of final follow-up (β  =  0.92, p  =  0.28) or duration of initial NRT treatment (β  =  0.99, p > 0.5). The overall relapse rate between the 12 months and final follow-up was 30.0% (95% CI 23.5% to 37.5%). This rate did not differ between NRT and control groups (OR 1.11, 95% CI 0.78 to 1.59), or length of initial NRT treatment. There was also no evidence that it varied according to length of final follow up. Due to relapse, the overall efficacy of NRT treatment in terms of additional ex-smokers declined from 10.7% over and above placebo (6.6% to 14.8%) after one year to 7.2% (3.8% to 11.3%) at an average of 4.3 years follow up.

Conclusions:The relative efficacy of a single course of NRT remains constant over many years. The majority of relapse after 12 months occurs within the first or second year and is not detectable thereafter, suggesting that NRT has a permanent effect on smoking cessation. However, initial relapse after one year has the effect of diminishing the number of ex-smokers that can be ultimately attributed to NRT. Results after only 6–12 months of follow-up, as used in existing reviews and treatment guidelines, will overestimate the lifetime benefit and cost-efficacy of NRT by about 30%. Because the long-term benefit of NRT is modest, tobacco dependence treatment might be better viewed as a chronic disorder, requiring repeated episodes of treatment.
The future of tobacco regulation: a response to a proposal for fundamental institutional change
Authors: Liberman Jonathan
Published: August 2006

There is much debate about the future of tobacco regulation. Some have argued that to achieve maximum possible reduction in the harm tobacco causes, new regulatory models that involve fundamental institutional change must be adopted. The tobacco industry will continue to undermine tobacco control, and, so it is argued, we must change the way in which it operates if we are to be able to make the necessary progress. Such proposals may have an immediate appeal, especially for those frustrated that progress in tobacco control is not as rapid as they would hope—with all the avoidable loss of life and livelihoods that that entails—but they need to be carefully analysed and assessed, and much thought must be applied before spending time and resources advocating for them. One such proposal, advanced by Borland, involves the establishment of a monopsonistic statutory purchasing agency and wholesale distributor of tobacco products. Borland argues the relative benefits of such a model as compared to a more “conventional” model. On close examination, the benefits of the Borland proposal, as compared to the conventional model, appear overstated, and the Borland proposal introduces significant regulatory problems. There is still much that can be achieved in tobacco regulation through more conventional approaches, and within the “existing system”. We should be wary of allowing the understandable allure of new or radical approaches to distract us from this reality.
Current concepts in nuclear pore electrophysiologyThis paper is one of a selection of papers published in this Special Issue, entitled The Nucleus: A Cell Within A Cell.
Authors: Bustamante José Omar
Published: August 2006

Over 4 decades ago, microelectrode studies of in situ nuclei showed that, under certain conditions, the nuclear envelope (NE) behaves as a barrier opposing the nucleocytoplasmic flow of physiological ions. As the nuclear pore complexes (NPCs) of the NE are the only pathways for direct nucleocytoplasmic flow, those experiments implied that the NPCs are capable of restricting ion flow. These early studies validated electrophysiology as a useful approach to quantify some of the mechanisms by which NPCs mediate gene activity and expression. Since electron microscopy (EM) and other non-electrophysiological investigations, showed that the NPC lumen is a nanochannel, the opinion prevailed that the NPC could not oppose the flow of ions and, therefore, that electrophysiological observations resulted from technical artifacts. Consequently, the initial enthusiasm with nuclear electrophysiology faded out in less than a decade. In 1990, nuclear electrophysiology was revisited with patch-clamp, the most powerful electrophysiological technique to date. Patch-clamp has consistently demonstrated that the NE has intrinsic ion channel activity. Direct demonstrations of the NPC on–off ion channel gating behavior were published for artificial conditions in 1995 and for intact living nuclei in 2002. This on–off switching/gating behavior can be interpreted in terms of a metastable energy barrier. In the hope of advancing nuclear electrophysiology, and to complement the other papers contained in this special issue of the journal, here I review some of the main technical, experimental, and theoretical issues of the field, with special focus on NPCs.
Endonuclear lipids in liver cellsThis paper is one of a selection of papers published in this Special Issue, entitled The Nucleus: A Cell Within A Cell.
Authors: Maté Sabina M. , Brenner Rodolfo R. , Ves-Losada Ana
Published: August 2006

Lipids are not only components of cell nucleus membranes, but are also found in the membrane-depleted nuclei where they fulfill special functions. We have investigated the lipid composition of membrane-depleted rat liver nuclei obtained by incubation with low Triton X-100 concentrations of 0.04% and 0.08%, which rendered them unaltered or hardly altered. Under these conditions, 26% of proteins and 22% of phospholipids were recovered. The main phospholipids were phosphatidylcholine > phosphatidylethanolamine > phosphatidylinositol ≥ phosphatidylserine and sphingomyelin (in decreasing concentrations). The fatty acid components of total lipids and phosphatidylcholine were mainly unsaturated. Over 40% belonged to the n–6 series (arachidonic ≥25% and linoleic 15%); approximately 40% corresponded to saturated acids and <10% were monoenoic. Endonuclear phosphatidylcholine was built up by 16 molecular species, the most abundant being 18:0–20:4 (32%), 16:0–20:4 (19%), 16:0–18:2 (13%), and 18:0–18:2 (11%). The fatty acid composition and phosphatidylcholine molecular species distribution in the membrane-depleted nucleus of rat liver showed patterns similar to the whole nucleus, mitochondria, microsomes, and homogenate of the parent liver cells, suggesting that endonuclear lipid pool composition is mainly determined by a liver organ profile.
The nuclear pore complex, nuclear transport, and apoptosisThis paper is one of a selection of papers published in this Special Issue, entitled The Nucleus: A Cell Within A Cell.
Authors: Fahrenkrog Birthe
Published: August 2006

The nuclear pore complex (NPC) is the sole gateway between the nucleus and the cytoplasm of interphase eukaryotic cells, and it mediates all trafficking between these 2 cellular compartments. As such, the NPC and nuclear transport play central roles in translocating death signals from the cell membrane to the nucleus where they initiate biochemical and morphological changes occurring during apoptosis. Recent findings suggest that the correlation between the NPC, nuclear transport, and apoptosis goes beyond the simple fact that NPCs mediate nuclear transport of key players involved in the cell death program. In this context, the accessibility of key regulators of apoptosis appears to be highly modulated by nuclear transport (e.g., impaired nuclear import might be an apoptotic trigger). In this review, recent findings concerning the unexpected tight link between NPCs, nuclear transport, and apoptosis will be presented and critically discussed.
Calcium signaling in the nucleusThis paper is one of a selection of papers published in this Special Issue, entitled The Nucleus: A Cell Within A Cell.
Authors: Gomes Dawidson A. , Leite M. Fatima , Bennett Anton M. , Nathanson Michael H.
Published: August 2006

Cytosolic Ca2+is a versatile secondary messenger that regulates a wide range of cellular activities. In the past decade, evidence has accumulated that free Ca2+within the nucleus also plays an important messenger function. Here we review the mechanisms and effects of Ca2+signals within the nucleus. In particular, evidence is reviewed that the nucleus contains the machinery necessary for production of inositol 1,4,5-trisphosphate and for inositol 1,4,5-trisphosphate receptor-mediated Ca2+release. The role of Ca2+signals within the nucleus is discussed including regulation of such critical cell functions as gene expression, activation of kinases, and permeability of nuclear pores.
G-protein-coupled receptors signalling at the cell nucleus: an emerging paradigmThis paper is one of a selection of papers published in this Special Issue, entitled The Nucleus: A Cell Within A Cell.
Authors: Gobeil Fernand , Fortier Audrey , Zhu Tang , Bossolasco Michela , Leduc Martin , Grandbois Michel , Heveker Nikolaus , Bkaily Ghassan , Chemtob Sylvain , Barbaz David
Published: August 2006

G-protein-coupled receptors (GPCRs) comprise a wide family of monomeric heptahelical glycoproteins that recognize a broad array of extracellular mediators including cationic amines, lipids, peptides, proteins, and sensory agents. Thus far, much attention has been given towards the comprehension of intracellular signaling mechanisms activated by cell membrane GPCRs, which convert extracellular hormonal stimuli into acute, non-genomic (e.g., hormone secretion, muscle contraction, and cell metabolism) and delayed, genomic biological responses (e.g., cell division, proliferation, and apoptosis). However, with respect to the latter response, there is compelling evidence for a novel intracrine mode of genomic regulation by GPCRs that implies either the endocytosis and nuclear translocation of peripheral-liganded GPCR and (or) the activation of nuclearly located GPCR by endogenously produced, nonsecreted ligands. A noteworthy example of the last scenario is given by heptahelical receptors that are activated by bioactive lipoids (e.g., PGE2and PAF), many of which may be formed from bilayer membranes including those of the nucleus. The experimental evidence for the nuclear localization and signalling of GPCRs will be reviewed. We will also discuss possible molecular mechanisms responsible for the atypical compartmentalization of GPCRs at the cell nucleus, along with their role in gene expression.
Stretch induced accumulation of total Ca and Na in cytosol and nucleus: a comparison between cardiac trabeculae and isolated myocytesThis paper is one of a selection of papers published in this Special Issue, entitled The Nucleus: A Cell Within A Cell.
Authors: Wilhelm J. , Kondratev D. , Christ A. , Gallitelli M.F.
Published: August 2006

By means of electron probe microanalysis (EPMA), we quantified changes in total sodium [Na] and calcium [Ca] concentration owing to the following: (i) local axial stretch (LAS) of isolated rat myocytes and (ii) end-to-end stretch (ETES) of rat ventricular trabeculae. For LAS, the distance between patch pipette and a cell-attached stylus was increased by maximally 20%; this activated a nonselective cationic current ISACof approximately –0.5 nA, which was blocked by streptomycin. Trabeculae were stretched end-to-end from 85% Lmaxto Lmax. Stretch increased cytosolic [Na]totalby 34% in isolated myocytes (p < 0.001) and by 43% in trabeculae (p < 0.001). The increment in nuclear [Na]totalwas 21% in myocytes (p < 0.01) and 20% in trabeculae (p < 0.001). Stretch increased [Ca]totalin isolated myocytes, in both cytosol (from 0.63 ± 0.09 to 1.09 ± 0.20 mmol/L, p < 0.05) and nucleus (from 0.33 ± 0.05 to 0.64 ± 0.13 mmol/L, p < 0.05). In trabeculae, the stretch-induced increment of 51% in cytosolic [Ca]totalremained nonsignificant (p < 0.15). In the nucleus, [Ca]totaldid not change. We interpret the difference of stretch on nuclear calcium in myocytes vs. trabeculae with the assumption that LAS, but not ETES, produces shear-stress components that translate the mechanical stimulus deeply into the cell where it may modulate [Ca]totalby signals independent of ISAC.
Intracrine signaling through lipid mediators and their cognate nuclear G-protein-coupled receptors: a paradigm based on PGE2, PAF, and LPA1receptorsThis paper is one of a selection of papers published in this Special Issue, entitled The Nucleus: A Cell Within A Cell.
Authors: Zhu Tang , Gobeil Fernand , Vazquez-Tello Alejandro , Leduc Martin , Rihakova Lenka , Bossolasco Michela , Bkaily Ghassan , Peri Krishna , Varma Daya R. , Orvoine Robert , Chemtob Sylvain
Published: August 2006

Prostaglandins (PGs), platelet-activating factor (PAF), and lysophosphatidic acid (LPA) are ubiquitous lipid mediators that play important roles in inflammation, cardiovascular homeostasis, and immunity and are also known to modulate gene expression of specific pro-inflammatory genes. The mechanism of action of these lipids is thought to be primarily dependent on their specific plasma membrane receptors belonging to the superfamily of G-protein-coupled receptors (GPCR). Increasing evidence suggests the existence of a functional intracellular GPCR population. It has been proposed that immediate effects are mediated via cell surface receptors whereas long-term responses are dependent upon intracellular receptor effects. Indeed, receptors for PAF, LPA, and PGE2(specifically EP1, EP3, and EP4) localize at the cell nucleus of cerebral microvascular endothelial cells of newborn pigs, rat hepatocytes, and cells overexpressing each receptor. Stimulation of isolated nuclei with these lipids reveals biological functions including transcriptional regulation of major genes, namely c-fos, cylooxygenase-2, and endothelial as well as inducible nitric oxide synthase. In the present review, we shall focus on the nuclear localization and signaling of GPCRs recognizing PGE2, PAF, and LPA phospholipids as ligands. Mechanisms on how nuclear PGE2, PAF, and LPA receptors activate gene transcription and nuclear localization pathways are presented. Intracrine signaling for lipid mediators uncover novel pathways to elicit their effects; accordingly, intracellular GPCRs constitute a distinctive mode of action for gene regulation.
NPY, ET-1, and Ang II nuclear receptors in human endocardial endothelial cellsThis paper is one of a selection of papers published in this Special Issue, entitled The Nucleus: A Cell Within A Cell.
Authors: Jacques Danielle , Sader Sawsan , Perreault Claudine , Abdel-Samad Dima , Jules Farah , Provost Chantale
Published: August 2006

Neuropeptide Y (NPY), endothelin-1 (ET-1), and angiotensin II (Ang II) are peptides that are known to play many important roles in cardiovascular homeostasis. The physiological actions of these peptides are thought to be primarily mediated by plasma membrane receptors that belong to the G-protein-coupled receptor superfamily. However, there is increasing evidence that suggests the existence of functional G-protein-coupled receptors at the level of the nucleus and that the nucleus could be a cell within a cell. Here, we review our work showing the presence in the nucleus of the NPY Y1receptor, the ETAand ETBreceptors, as well as the AT1and AT2receptors and their respective ligands. This work was carried out in 20-week-old fetal human endocardial endothelial cells. Our results demonstrate that nuclear Y1, AT1, and ETAreceptors modulate nuclear calcium in these cells.
CP CONSERVED NONLEPTONIC K → πππ DECAYS IN THE CHIRAL QUARK MODEL
Authors: LASHIN E. I.
Published: August 2006

The CP conserved nonleptonic K → πππ decays are discussed within the chiral quark model, including chiral perturbation theory corrections. For the chiral loop correction, they are presented in a way to be more manageable and easier for use. Furthermore a new identity for the imaginary part of the chiral loop corrections is derived. All amplitudes are parametrized in terms of quark and gluon condensate and the constituent quark mass. The same values for these parameters that can be obtained by a fit of the ΔI = 1/2 rule in K → 2π give a reasonably good fit in the K → 3π case. We compare with the work of other groups.
COMPARISONS AND COMBINATIONS OF REACTOR AND LONG-BASELINE NEUTRINO OSCILLATION MEASUREMENTS
Authors: MAHN K. B. M. , SHAEVITZ M. H.
Published: August 2006

We investigate how the data from various future neutrino oscillation experiments will constrain the physics parameters for a three active neutrino mixing model. The investigations properly account for the degeneracies and ambiguities associated with the phenomenology as well as estimates of experimental measurement errors. Combinations of various reactor measurements with the expected J-PARC (T2K) and NuMI offaxis (Nova) data, both with and without the increased flux associated with proton driver upgrades, are considered. The studies show how combinations of reactor and offaxis data can resolve degeneracies (e.g. the θ23 degeneracy) and give more precise information on the oscillation parameters. A primary purpose of this investigation is to establish the parameter space regions where CP violation can be discovered and where the mass hierarchy can be determined. We find that, even with augmented flux from proton drivers, such measurements demand that sin 2 2θ13 be fairly large and in the range where it is measurable by reactor experiments.
2 + 1 ABELIAN "GAUGE THEORY" INSPIRED BY IDEAL HYDRODYNAMICS
Authors: KRISHNASWAMI GOVIND S.
Published: August 2006

We study a possibly integrable model of Abelian gauge fields on a two-dimensional surface M, with volume form μ. It has the same phase-space as ideal hydrodynamics, a coadjoint orbit of the volume-preserving diffeomorphism group of M. Gauge field Poisson brackets differ from the Heisenberg algebra, but are reminiscent of Yang–Mills theory on a null surface. Enstrophy invariants are Casimirs of the Poisson algebra of gauge invariant observables. Some symplectic leaves of the Poisson manifold are identified. The Hamiltonian is a magnetic energy, similar to that of electrodynamics, and depends on a metric whose volume element is not a multiple of μ. The magnetic field evolves by a quadratically nonlinear "Euler" equation, which may also be regarded as describing geodesic flow on SDiff (M, μ). Static solutions are obtained. For uniform μ, an infinite sequence of local conserved charges beginning with the Hamiltonian are found. The charges are shown to be in involution, suggesting integrability. Besides being a theory of a novel kind of ideal flow, this is a toy-model for Yang–Mills theory and matrix field theories, whose gauge-invariant phase-space is conjectured to be a coadjoint orbit of the diffeomorphism group of a noncommutative space.
LOCAL COSMIC STRING AND C-FIELD
Authors: RAHAMAN F. , MONDAL R. , KALAM M.
Published: August 2006

We investigate a local cosmic string with a phenomenological energy–momentum tensor as prescribed by Vilenkin, in the presence of C-field. The solutions of full nonlinear Einstein's equations for exterior and interior regions of such a string are presented.
QUANTUM FLUCTUATIONS OF ROTATING STRINGS IN AdS5 × S5
Authors: FUJI HIROYUKI , SATOH YUJI
Published: August 2006

We discuss quantum fluctuations of a class of rotating strings in AdS 5 × S 5. In particular, we develop a systematic method to compute the one-loop sigma-model effective actions in closed forms as expansions for large spins. As examples, we explicitly evaluate the leading terms for the constant radii strings in the SO (6) sector with two equal spins, the SU (2) sector, and the SL (2) sector. We also obtain the leading quantum corrections to the space–time energy for these sectors.
NEGATIVE PRESSURES IN QED VACUUM IN AN EXTERNAL MAGNETIC FIELD
Authors: PÉREZ ROJAS H. , RODRÍGUEZ QUERTS E.
Published: August 2006

Our aim is to study the electron–positron vacuum pressures in the presence of a strong magnetic field B. To that end, we obtain a general energy–momentum tensor, depending on external parameters, which in the zero temperature and zero density limit leads to vacuum expressions which are approximation-independent. Anisotropic pressures arise, and in the tree approximation of the magnetic field case, the pressure along B is positive, whereas perpendicular to B it is negative. Due to the common axial symmetry, the formal analogy with the Casimir effect is discussed, which in addition to the usual negative pressure perpendicular to the plates, there is a positive pressure along the plates. The formal correspondence between the Casimir and blackbody energy–momentum tensors is also discussed. The fermion hot vacuum behavior in a magnetic field is also briefly discussed.
VENTURE ARCHETYPES AND THE ENTREPRENEURIAL EVENT: CROSS-CULTURAL EMPIRICAL EVIDENCE
Authors: KOLLMANN TOBIAS , KUCKERTZ ANDREAS
Published: August 2006

This study sheds light on the so-called 'entrepreneurial event' which is of utmost importance within the entrepreneurial process. We develop a framework describing the occurrence of such an event in terms of characteristics of the business opportunity as well as in terms of characteristics of the implementation process. Furthermore, possible entrepreneurial events and influencing factors are theoretically identified. To test our assumptions, a cross-cultural survey among 110 entrepreneurs from seven distinct cultural regions was conducted. Empirical results suggest there are primarily two classes of entrepreneurial events: One part of the entrepreneurial population perceives the moment of first entrepreneurial action as their entrepreneurial event, while the other part needs market acceptance to believe in the viability of the entrepreneurial project. Furthermore, we provide evidence for the existence of four venture archetypes which are related to the circumstances of the entrepreneurial event.
DON'T BLAME THE ENTREPRENEUR, BLAME GOVERNMENT: THE CENTRALITY OF THE GOVERNMENT IN ENTERPRISE DEVELOPMENT; LESSONS FROM ENTERPRISE FAILURE IN ZIMBABWE
Authors: CARTER STEVEN , WILTON WILTON
Published: August 2006

Success and failure of enterprise development is dependent on both the entrepreneur and the environment in which entrepreneurial activities take place. The entrepreneur is motivated to start an enterprise if the environment is supportive and is discouraged if the environment is not supportive. Only governments are better suited to influence the financial, education and training, legal and regulatory, political and economic environments, whose effects affect enterprise development. Failure by governments to address the environmental factors leads to failure in enterprise development. The paper argues the governments to ensure conducive environments for positive enterprise development.
AN APPLICATION OF DIFFERENTIAL TRANSFORMATION TO STABILITY ANALYSIS OF HEAVY COLUMNS
Authors: CHAI Y. H. , WANG C. M.
Published: August 2006

This paper uses a recently developed technique, known as the differential transformation, to determine the critical buckling load of axially compressed heavy columns of various support conditions. In solving the problem, it is shown that the differential transformation technique converts the governing differential equation into an algebraic recursive equation, which must be solved together with the differential transformation of the boundary conditions. Although a fairly large number of terms are required for convergence of the solution, the differential transformation method is nonetheless efficient and fairly easy to implement. The method is also shown to be very accurate when compared with a known analytical solution. The stability of heavy columns is further examined using approximate formulae currently available in the literature. In this case, the differential transformation method offers a reference for assessing the accuracy of the approximate buckling formulae.
PARTIAL CONSTRAINED VISCOELASTIC DAMPING TREATMENT OF STRUCTURES: A MODAL STRAIN ENERGY APPROACH
Authors: MOREIRA R. A. S. , RODRIGUES J. DIAS
Published: August 2006

The constrained viscoelastic layer damping treatment is an effective means for the passive vibration control of plate and beam-kind structures. In order to reduce the treatment cost, while minimizing structural modifications, particularly the increase in mass, constrained viscoelastic treatments can be successfully applied in a partial and localized manner. The effectiveness of these treatments depends on their extension and relative location with respect to the target mode shape, which is not usually expeditiously established. In order to minimize the cost of the numerical optimization of the partial treatments, an efficient numerical methodology based on the ratio between the modal strain energy of the treated area and that of the structure is hereby proposed. This method is used in the analysis of the location and extension effects of partial constrained viscoelastic treatments on the modal damping of thin plates. The numerical results are verified through an experimental study on specimens with partial constrained viscoelastic layer damping treatments.
A Human Monoclonal Antibody Cocktail as a Novel Component of Rabies Postexposure Prophylaxis
Authors: de Kruif John , Bakker Alexander B.H. , Marissen Wilfred E. , Kramer R. Arjen , Throsby Mark , Rupprecht Charles E. , Goudsmit Jaap
Published: August 2006

The currently recommended treatment for individuals exposed to rabies virus is the combined administration of rabies vaccine and rabies immune globulin (RIG). This review sets out the criteria used to guide development of a cocktail of human monoclonal antibodies as a replacement for RIG. Using this process as a model, the general requirements for development of safe and efficacious monoclonal antibody alternatives to currently used polyclonal serum products are discussed.
Effects of estradiol on phenylephrine contractility associated with intracellular calcium release in rat aorta
Authors: Castillo Carlos , Ceballos Guillermo , Rodríguez Daniel , Villanueva Cleva , Medina Roberto , López Jorge , Méndez Enrique , Castillo Enrique F.
Published: August 2006

The ability of estradiol to affect phenylephrine-induced contraction and the subsequent increase in resting tone, associated with capacitative Ca2+entry across the plasma membrane, was evaluated in rat aortic rings incubated in Ca2+-free solution. The incubation with estradiol (1–100 nM, 5 min) inhibited both the phenylephrine-induced contraction and the IRT. Neither cycloheximide (1 μM; inhibitor of protein synthesis) nor tamoxifen (1 μM; blocker of estrogenic receptors) modified the effects of estradiol. Estradiol (100 μM) also blocked the contractile response to serotonin (10 μM) but not to caffeine (10 mM). In addition, estradiol (100 μM) inhibited the contractile responses to cyclopiazonic acid (1 μM; selective Ca2+-ATPase inhibitor) associated with capacitative Ca2+influx through non-L-type Ca2+channels. Finally, estradiol inhibited the Ca2+-induced increases in intracellular free Ca2+(after pretreatment with phenylephrine) in cultured rat aorta smooth muscle cells incubated in Ca2+-free solution. In conclusion, estradiol interfered in a concentration-dependent manner with Ca2+-dependent contractile effects mediated by the stimuli of α1-adrenergic and serotonergic receptors and inhibited the capacitative Ca2+influx through both L-type and non-L-type Ca2+channels. Such effects are in essence nongenomic and not mediated by the intracellular estrogenic receptor.
Renal expression of organic anion transporter OAT2 in rats and mice is regulated by sex hormones
Authors: Ljubojević Marija , Balen Daniela , Breljak Davorka , Kušan Marija , Anzai Naohiko , Bahn Andrew , Burckhardt Gerhard , Sabolić Ivan
Published: August 2006

The renal reabsorption and/or excretion of various organic anions is mediated by specific organic anion transporters (OATs). OAT2 (Slc22a7) has been identified in rat kidney, where its mRNA expression exhibits gender differences [females (F) > males (M)]. The exact localization of OAT2 protein in the mammalian kidney has not been reported. Here we studied the expression of OAT2 mRNA by RT-PCR and its protein by Western blotting (WB) and immunocytochemistry (IC) in kidneys of adult intact and gonadectomized M and F, sex hormone-treated castrated M, and prepubertal M and F rats, and the protein in adult M and F mice. In adult rats, the expression of OAT2 mRNA was predominant in the outer stripe (OS) tissue, exhibiting 1) gender dependency (F > M), 2) upregulation by castration and downregulation by ovariectomy, and 3) strong downregulation by testosterone and weak upregulation by estradiol and progesterone treatment. A polyclonal antibody against rat OAT2 on WB of isolated renal membranes labeled a ∼66-kDa protein band that was stronger in F. By IC, the antibody exclusively stained brush border (BB) of the proximal tubule S3 segment (S3) in the OS and medullary rays (F > M). In variously treated rats, the pattern of 66-kDa band density in the OS membranes and the staining intensity of BB in S3 matched the mRNA expression. The expression of OAT2 protein in prepubertal rats was low and gender independent. In mice, the expression pattern largely resembled that in rats. Therefore, OAT2 in rat (and mouse) kidney is localized to the BB of S3, exhibiting gender differences (F > M) that appear in puberty and are caused by strong androgen inhibition and weak estrogen and progesterone stimulation.
Toll-like receptor (TLR4) shedding and depletion: acute proximal tubular cell responses to hypoxic and toxic injury
Authors: Zager Richard A. , Johnson Ali C. M. , Lund Steven , Randolph-Habecker Julie
Published: August 2006

Acute renal failure (ARF) induces tubular hyperresponsiveness to TLR4 ligands, culminating in exaggerated renal cytokine/chemokine production. However, the fate of TLR4 protein during acute tubular injury remains unknown. The study sought new insights into this issue. Male CD-1 mice were subjected to 1) unilateral ischemia-reperfusion (I/R), 2) cisplatin (CP) nephrotoxicity, or 3) glycerol-induced myohemoglobinuric ARF. Renal cortical TLR4 protein (Western blotting, immunohistochemistry) and TLR4 mRNA levels (RT-PCR) were determined thereafter (90 min-4 days). Urinary TLR4 excretion post-I/R or CP injection was also assessed. To gain proximal tubule-specific results, TLR4 protein and mRNA were quantified in posthypoxic or oxidant (Fe)-challenged isolated mouse tubules. Finally, TLR4 mRNA was determined in antimycin A-injured cultured proximal tubular (HK-2) cells. Acute in vivo renal injury reduced proximal tubule TLR4 content. These changes corresponded with the appearance of TLR4 fragment(s) in urine and a persistent increase in renal cortical TLR4 mRNA. Isolated proximal tubules responded to injury with rapid TLR4 reductions, dramatic extracellular TLR4 release, and increases in TLR4 mRNA. Glycine blocked these processes, implying membrane pore formation was involved. HK-2 cell injury increased TLR4 mRNA, but not protein levels, suggesting intact transcriptional, but not translational, pathways. Diverse forms of acute tubular injury rapidly reduce proximal tubular TLR4 content. Plasma membrane TLR4 release through glycine-suppressible pores, possibly coupled with a translation block, appears to be involved. Rapid postinjury urinary TLR4 excretion suggests its potential utility as a “biomarker” of impending ARF.
Expression and actions of HIF prolyl-4-hydroxylase in the rat kidneys
Authors: Li Ningjun , Yi Fan , Sundy Christina M. , Chen Li , Hilliker Molly L. , Donley Dustin K. , Muldoon Daniel B. , Li Pin-Lan
Published: August 2006

Hypoxia inducible factor (HIF) prolyl-4-hydroxylase domain-containing proteins (PHDs) promote the degradation of HIF-1α. Because HIF-1α is highly expressed in the renal medulla and HIF-1α-targeted genes such as nitric oxide synthase, cyclooxygenase, and heme oxygenase are important in the regulation of renal medullary function, we hypothesized that PHD regulates HIF-1α levels in the renal medulla and, thereby, participates in the control of renal Na+excretion. Using real-time RT-PCR, Western blot, and immunohistochemical analyses, we have demonstrated that all three isoforms of PHD, PHD1, PHD2, and PHD3, are expressed in the kidneys and that PHD2 is the most abundant isoform. Regionally, all PHDs exhibited much higher levels in renal medulla than cortex. A furosemide-induced increase in renal medullary tissue Po2significantly decreased PHD levels in renal medulla, whereas hypoxia significantly increased mRNA levels of PHDs in cultured renal medullary interstitial cells, indicating that O2regulates PHDs. Functionally, the PHD inhibitor l-mimosine (l-Mim, 50 mg·kg−1·day−1ip for 2 wk) substantially upregulated HIF-1α expression in the kidneys, especially in the renal medulla, and remarkably enhanced (by >80%) the natriuretic response to renal perfusion pressure in Sprague-Dawley rats. Inhibition of HIF transcriptional activity by renal medullary transfection of HIF-1α decoy oligodeoxynucleotides attenuated l-Mim-induced enhancement of pressure natriuresis, which confirmed that HIF-1α mediated the effect of l-Mim. These results indicate that highly expressed PHDs in the renal medulla make an important contribution to the control of renal Na+excretion through regulation of HIF-1α and its targeted genes.
Dopamine D2 Receptor Modulation of K+ Channel Activity Regulates Excitability of Nucleus Accumbens Neurons at Different Membrane Potentials
Authors: Perez Mariela F. , White Francis J. , Hu Xiu-Ti
Published: August 2006

The nucleus accumbens (NAc) is a forebrain area in the mesocorticolimbic dopamine (DA) system that regulates many aspects of drug addiction. Neuronal activity in the NAc is modulated by different subtypes of DA receptors. Although DA signaling has received considerable attention, the mechanisms underlying D2-class receptor (D2R) modulation of firing in medium spiny neurons (MSNs) localized within the NAc remain ambiguous. In the present study, we performed whole cell current-clamp recordings in rat brain slices to determine whether and how D2R modulation of K+ channel activity regulates the intrinsic excitability of NAc neurons in the core region. D2R stimulation by quinpirole or DA significantly and dose-dependently decreased evoked Na+ spikes. This D2R effect on inhibiting evoked firing was abolished by antagonism of D2Rs, reversed by blockade of voltage-sensitive, slowly inactivating A-type K+ currents ( IAs), or eliminated by holding membrane potentials at levels in which IAs was inactivated. It was also mimicked by inhibition of cAMP-dependent protein kinase (PKA) activity, but not phosphatidylinositol-specific phospholipase C (PI-PLC) activity. Moreover, D2R stimulation also reduced the inward rectification and depolarized the resting membrane potentials (RMPs) by decreasing “leak” K+ currents. However, the D2R effects on inward rectification and RMP were blocked by inhibition of PI-PLC, but not PKA activity. These findings indicate that, with facilitated intracellular Ca2+ release and activation of the D2R/Gq/PLC/PIP2 pathway, the D2R-modulated changes in the NAc excitability are dynamically regulated and integrated by multiple K+ currents, including but are not limited to IAs, inwardly rectifying K+ currents ( IKir), and “leak” currents ( IK-2P).
Endogenous Activation of Adenosine A1Receptors Accelerates Ischemic Suppression of Spontaneous Electrocortical Activity
Authors: Ilie Andrei , Ciocan Dragos , Zagrean Ana-Maria , Nita Dragos Alexandru , Zagrean Leon , Moldovan Mihai
Published: August 2006

Cerebral ischemia induces a rapid suppression of spontaneous brain rhythms prior to major alterations in ionic homeostasis. It was found in vitro during ischemia that the rapidly formed adenosine, resulting from the intracellular breakdown of ATP, may inhibit synaptic transmission via the A1receptor subtype. The link between endogenous A1receptor activation during ischemia and the suppression of spontaneous electrocortical activity has not yet been established in the intact brain. The aim of this study was to investigate in vivo the effects of A1receptor antagonism by 8-cyclopentyl-1,3-dipropylxanthine (DPCPX) on the time to electrocortical suppression during global cerebral ischemia. Adult male Wistar rats under chloral hydrate anesthesia were subjected to 1-min transient “four-vessel occlusion” ischemic episodes, separated by 20-min reperfusion. The rats were injected intraperitoneally with either 1.25 mg/kg DPCPX dissolved in 2 ml/kg dimethyl sulfoxide (DMSO) or the same volume of DMSO alone, 15 min before the third ischemic episode. Time to electrocortical suppression was estimated based on the decay of the root mean square of two-channel electrocorticographic recordings. During the first two ischemic episodes, electrocortical suppression appeared after ∼12 s in both groups. After DMSO administration, ischemic suppression remained unchanged. After DPCPX administration, the time to electrocortical suppression was increased by ∼10 s, and bursts of activity were recorded during the entire ischemia. These effects disappeared within 15 h after DPCPX administration. Our data provide evidence that during cerebral ischemia endogenous activation of A1receptors accelerates the electrical “shut-down” of the whole brain.