bluuebunny/crossref_metadata_2025 huggingface dataset:
Evolution of nonlinear Rayleigh waves in a coated substrate
Authors: Ohm Won-Suk , Hamilton Mark F.
Published: June 2004

Nonlinear Rayleigh waves propagating in a substrate coated with a thin elastic film are studied numerically. The evolution model consists of the nonlinear spectral equations of Zabolotskaya [J. Acoust. Soc. Am. 91, 2569–2575 (1992)] augmented ad hoc to include film dispersion. The dispersion relation is obtained from linear theory but is otherwise exact. Both loading and stiffening films are considered. Computations are performed for nonlinear evolution of an initially sinusoidal Rayleigh wave under three distinct dispersion regimes corresponding to different film thicknesses. The validity of the evolution model is also examined.
Defining optimal axial and lateral resolution for estimating scatterer properties from volumes using ultrasound backscatter
Authors: Oelze Michael L. , O’Brien William D.
Published: June 2004

The rf signals used to construct conventional ultrasound B-mode images contain frequency-dependent information that can be examined through the backscattered power spectrum. Typically, the backscattered power spectrum is calculated from a region of interest (ROI) within some larger volume. The dimensions of the ROI are defined axially by the spatial length corresponding to the time gate and laterally by the number of scan lines included in the ROI. Averaging the backscattered power spectra from several independent scan lines can reduce the presence of noise caused by electronics and by the random scatterer spacings, but also decreases the lateral resolution of the interrogation region. Furthermore, larger axial gate lengths can be used to reduce the effects of noise and improve the precision and accuracy of scatterer property estimates but also decreases the axial resolution. A trade-off exists between the size of the ROI (the number of scan lines used, the separation distance between each scan line, the axial gate length) and the accuracy and precision of scatterer property estimates. A series of simulations and measurements from physical phantoms were employed to examine these trade-offs. The simulations and phantom measurements indicated the optimal lateral and axial sizes of the ROI, where estimate accuracy and precision were better than 10% and 5%, respectively, occurred at 4 to 5 beamwidths laterally and 15 to 20 spatial pulse lengths axially.
On the natural frequencies of short cylinders and the universal point. Direct determination of the shear modulus
Authors: Nieves Francisco J. , Gascón Fraǹcisco , Bayón Ana
Published: June 2004

This work presents a study of the relation between the lowest nondimensional natural frequencies of a short, free cylinder vibrating in axisymmetric modes, its slenderness ratio, and its Poisson’s ratio. Ritz’s method applied to the study of the symmetric vibration of cylinders confirms that all curves, which show the dependence of frequency versus slenderness, pass through a point, called universal, independently of Poisson’s ratio. The lowest universal frequency is 2.6036 and corresponds to a cylinder whose quotient of its length and its diameter is 0.853 22. The rules leading to the identification of the first symmetric mode are inferred from the numerical results. A cylinder with universal slenderness ratio is set into free vibration by applying an axial impact. The lowest axisymmetric natural frequencies are obtained from measurement of the axial displacement by speckle interferometry. A simple arithmetical operation permits calculation of the shear modulus from the value of the first symmetric frequency, the diameter of the cylinder, and its density. The quotient of frequencies of two similar cylinders is studied as a function of their elastic properties and diameters.
Roles of the Two
Drosophila
CRYPTOCHROME Structural Domains in Circadian Photoreception
Authors: Busza Ania , Emery-Le Myai , Rosbash Michael , Emery Patrick
Published: June 2004

CRYPTOCHROME (CRY) is the primary circadian photoreceptor in
Drosophila
. We show that CRY binding to TIMELESS (TIM) is light-dependent in flies and irreversibly commits TIM to proteasomal degradation. In contrast, CRY degradation is dependent on continuous light exposure, indicating that the CRY-TIM interaction is transient. A novel
cry
mutation (

cry
m

) reveals that CRY's photolyase homology domain is sufficient for light detection and phototransduction, whereas the carboxyl-terminal domain regulates CRY stability, CRY-TIM interaction, and circadian photosensitivity. This contrasts with the function of
Arabidopsis
CRY domains and demonstrates that insect and plant cryptochromes use different mechanisms.
Control and Measurement of Three-Qubit Entangled States
Authors: Roos Christian F. , Riebe Mark , Häffner Hartmut , Hänsel Wolfgang , Benhelm Jan , Lancaster Gavin P. T. , Becher Christoph , Schmidt-Kaler Ferdinand , Blatt Rainer
Published: June 2004

We report the deterministic creation of maximally entangled three-qubit states—specifically the Greenberger-Horne-Zeilinger (GHZ) state and the W state—with a trapped-ion quantum computer. We read out one of the qubits selectively and show how GHZ and W states are affected by this local measurement. Additionally, we demonstrate conditional operations controlled by the results from reading out one qubit. Tripartite entanglement is deterministically transformed into bipartite entanglement by local operations only. These operations are the measurement of one qubit of a GHZ state in a rotated basis and, conditioned on this measurement result, the application of single-qubit rotations.
Programs of the Mind
Authors: Marcus Gary
Published: June 2004

What Is Thought?
. by Eric B. Baum. MIT Press, Cambridge, MA, 2004. 492 pp. $40, £25.95. ISBN 0-262-02548-5.

Approaching the problem of the mind from a computer science perspective, Baum argues for a computational explanation of though--one that sees the mind as "a complex but compact program."
Newspaper framing of fatal motor vehicle crashes in four Midwestern cities in the United States, 1999–2000
Authors: Connor S M , Wesolowski K
Published: June 2004

Objective:To examine the public health messages conveyed by newspaper coverage of fatal motor vehicle crashes and determine the extent to which press coverage accurately reflects real risks and crash trends.

Methods:Crash details were extracted from two years of newspaper coverage of fatal crashes in four Midwestern cities in the United States. Details and causal factors identified by reporters were compared to data from the National Highway Traffic Safety Administration’s Fatality Analysis Reporting System (FARS) using odds ratios and two tailed z tests.

Results:Papers covered 278 fatal crashes over the two year period, in contrast to 846 fatal crashes documented in FARS. Papers assigned blame in 90% of crashes covered, under-reported restraint use and driver’s risk of death, failed to reflect the protective value of restraints, and misrepresented the roles played by alcohol and teen drivers.

Conclusion:Newspaper coverage did not accurately reflect real risk. Papers presented fatal crashes as dramas with a victim/villain storyline; in keeping with this narrative strategy, papers were most likely to cover stories where a driver survived to take the blame. By highlighting crashes that diverge from the norm, focusing on the assignment of blame to a single party, and failing to convey the message that preventive practices like seatbelt use increase odds for survival, newspapers removed crashes from a public health context and positioned them as individual issues. Public health practitioners can work with media outlets in their areas to draw attention to misrepresentations and change the way these stories are framed.
Injuries from paintball game related activities in the United States, 1997–2001
Authors: Conn J M , Annest J L , Gilchrist J , Ryan G W
Published: June 2004

Objective:To quantify and characterize injuries resulting from paintball game related activities among persons ⩾7 years in the United States.

Setting:Hospitals included in the National Electronic Injury Surveillance System (NEISS); these are composed of a stratified probability sample of all hospitals in the United States with emergency departments.

Methods:Using NEISS, non-fatal injury data for paintball game related injury cases from 1997–2001 were obtained from emergency department records. Participation estimates used to calculate injury rates were obtained from a yearly survey funded by the National Sporting Goods Association.

Results:An estimated 11 998 persons ⩾7 years with paintball game related injuries were treated in emergency departments from 1997–2001, with an annual average rate of 4.5 per 10 000 participants (95% confidence interval 3.3 to 5.7). The paintball game related injury rate was highest for 18–24 year olds (4.9 per 10 000 participants) and most injuries (94.0%) occurred among males. Almost 60% of all injured persons ⩾7 years were treated for paintball pellet wounds of which most were to the eye. While 76.9% of injured persons ages 7–17 years were treated for paintball pellet wounds, almost 40% of those ⩾18 years were treated for injuries resulting from overexertion or a fall. Lower extremity injuries were also common (23.0%), mostly from overexertion. Most injured persons (95.5%) were treated and released.

Conclusions:As paintball games become more popular, efforts are needed to increase training, enforce rules, and educate participants about how to stay safe, such as wearing protective eye gear, when engaged in paintball games at home, in a public area, or in a sports field.
Practical introduction to record linkage for injury research
Authors: Clark D E
Published: June 2004

The frequency of early fatality and the transient nature of emergency medical care mean that a single database will rarely suffice for population based injury research. Linking records from multiple data sources is therefore a promising method for injury surveillance or trauma system evaluation. The purpose of this article is to review the historical development of record linkage, provide a basic mathematical foundation, discuss some practical issues, and consider some ethical concerns.

Clerical or computer assisted deterministic record linkage methods may suffice for some applications, but probabilistic methods are particularly useful for larger studies. The probabilistic method attempts to simulate human reasoning by comparing each of several elements from the two records. The basic mathematical specifications are derived algebraically from fundamental concepts of probability, although the theory can be extended to include more advanced mathematics.

Probabilistic, deterministic, and clerical techniques may be combined in different ways depending upon the goal of the record linkage project. If a population parameter is being estimated for a purely statistical study, a completely probabilistic approach may be most efficient; for other applications, where the purpose is to make inferences about specific individuals based upon their data contained in two or more files, the need for a high positive predictive value would favor a deterministic method or a probabilistic method with careful clerical review. Whatever techniques are used, researchers must realize that the combination of data sources entails additional ethical obligations beyond the use of each source alone.
Recreational injuries among older Americans, 2001
Authors: Gerson L W , Stevens J A
Published: June 2004

Objective:To describe the epidemiology of non-fatal recreational injuries among older adults treated in United States emergency departments including national estimates of the number of injuries, types of recreational activities, and diagnoses.

Methods:Injury data were provided by the National Electronic Injury Surveillance System-All Injury Program (NEISS-AIP), a nationally representative subsample of 66 out of 100 NEISS hospitals. Potential cases were identified using the NEISS-AIP definition of a sport and recreation injury. The authors then reviewed the two line narrative to identify injuries related to participation in a sport or recreational activity among men and women more than 64 years old.

Results:In 2001, an estimated 62 164 (95% confidence interval 35 570 to 88 758) persons ≥65 years old were treated in emergency departments for injuries sustained while participating in sport or recreational activities. The overall injury rate was 177.3/100 000 population with higher rates for men (242.5/100 000) than for women (151.3/100 000). Exercising caused 30% of injuries among women and bicycling caused 17% of injuries among men. Twenty seven percent of all treated injuries were fractures and women (34%) were more likely than men (21%) to suffer fractures.

Conclusions:Recreational activities were a frequent cause of injuries among older adults. Fractures were common. Many of these injuries are potentially preventable. As more persons engage in recreational activities, applying known injury prevention strategies will help to reduce the incidence of these injuries.
Reducing social inequalities in smoking: can evidence inform policy? A pilot study: Table 1
Authors: Ogilvie D , Petticrew M
Published: June 2004

Objective:To assess the potential contribution of evidence from existing systematic reviews of effectiveness to answering the question: what works in reducing social inequalities in smoking?

Data source:The Cochrane Library (2002/4).

Study selection:Systematic reviews of the effectiveness of community based tobacco control interventions, and all the primary studies included in one of these reviews.

Data extraction:Reviews and primary studies were assessed for intent to assess the social distribution of intervention effects, information about the social inclusiveness or targeting of interventions, baseline sociodemographic data collected on participants, and estimates of effect size stratified by sociodemographic variables.

Data synthesis:Only one review aimed to examine outcomes stratified by sex, age or socioeconomic status, and these aims were only achieved with respect to sex. Sociodemographic data about participants were frequently collected in primary studies, but not used to compare intervention effects between social groups.

Conclusions:There may be scope for using existing research more effectively to contribute to evidence based policy to reduce social inequalities in smoking—by explicitly seeking stratified outcome data in new systematic reviews, by re-analysing original datasets, and/or by meta-analysis of individual participant data.
Exposure to environmental tobacco smoke (ETS) and determinants of support for complete smoking bans in psychiatric settings
Authors: Willemsen M C , Görts C A , Van Soelen P , Jonkers R , Hilberink S R
Published: June 2004

Objective:To measure environmental tobacco smoke (ETS) exposure in psychiatric settings and to assess determinants of support for complete smoking bans.

Design:Cross sectional study

Setting:Dutch psychiatric hospitals, outpatient care institutions, and sheltered home facilities.

Subjects:A random sample of 540 treatment staff, 306 attendants/nurses, and 93 patients.

Main outcome measures:Self reported ETS exposure, current smoking policy, compliance with smoking policy, beliefs about smoking bans.

Results:87% of respondents were exposed to tobacco smoke in psychiatric institutions; 29% said that on an average day they were exposed to “a lot of smoke”. Although ETS originates mainly from smoking patients, both non-compliance from patients and employees with existing bans resulted in non-smokers being exposed to ETS. Due to non-compliance, ETS exposure was quite high when there is a general smoking ban (designated areas option). Only with a complete ban was compliance good and employees sufficiently protected from ETS exposure. Psychiatrists, psychologists, physicians, attendants, and nurses were most concerned about resistance from patients, partly because of the fear of infringing on patients’ freedom to smoke.

Conclusions:Complete smoking bans are the only way to fully protect those working in psychiatry from ETS exposure, mainly because general smoking bans are not sufficiently complied with. Communication strategies to improve compliance with complete bans are crucial to protect those working in psychiatry from ETS. Compliance could be improved by addressing the belief that the ban will effectively result in less ETS exposure and the issue of patients’ freedom to smoke versus employees’ right to work in a smoke-free environment.
Tobacco harm reduction: what do the experts think?: Table 1
Authors: Martin E G , Warner K E , Lantz P M
Published: June 2004

Objective:To assess experts’ opinions about the future of, and potential to improve individual and public health through “tobacco harm reduction” (THR), the use of novel nicotine containing products purporting to reduce the health risks from cigarette smoking.

Design:Semi-structured telephone interviews on nine topic areas, with qualitative content analysis of coded transcripts.

Participants:29 professionals with expertise related to tobacco and interest in THR, including prominent tobacco control advocates (7), pharmaceutical (3) and tobacco industry scientists/officials (5), non-industry scientists (12), and Congressional staff (2).

Results:Respondents agreed that harm reduction is at minimum theoretically plausible, that characteristics of “good” and “bad” THR products can be identified, that government regulation is essential but not likely in the foreseeable future, and that additional scientific data are very much needed. However, there was no consensus on specifics, such as preferred regulatory strategies or examples of ideal THR products. Disagreement was seen not only across but also within respondent categories. Mistrust of key stakeholders—for example, tobacco control advocates distrust of tobacco industry scientists and vice versa—was pervasive, and cited frequently as a barrier to regulation and collaboration.

Conclusions:Continued dialogue and debate are essential as we enter a new and uncertain era of products purporting to reduce tobacco produced harm. Experts have concluded that effective government regulation is crucial to minimising the risks associated with THR and maximising potential benefits.
Nicotine delivery capabilities of smokeless tobacco products and implications for control of tobacco dependence in South Africa: Table 1
Authors: Ayo-Yusuf O A , Swart T J P , Pickworth W B
Published: June 2004

Objectives:Smokeless tobacco (SLT) use is popular among black South African women and children. The study sought to determine the nicotine delivery capability of popular industrialised and traditional SLT brands in South Africa, and to provide information for policy action by regulatory authorities.

Design:Laboratory chemical analysis of four industrialised and one traditional SLT products commercially available, using previously published analytical methods. Potential for dependence was inferred from nicotine delivery capabilities determined by the percentage free base nicotine.

Measurements:Moisture, pH, total nicotine, and percentage free base nicotine.

Results:Total nicotine content was between 6–16 mg/g. The pH varied between 7–10 and this correlated with percentage free base nicotine, which ranged between 10–99%. The nicotine delivery capability of the traditional product was lower than that of the industrialised products except for the recently introduced portion bag snus, which had comparable total nicotine but the lowest pH and percentage free base nicotine. The most popular SLT brands showed the highest percentage free base nicotine ever reported for any industrialised SLT or cigarette brands. Small cans contained higher nicotine than the large cans of the same brand tested. Findings from the study support a potential for limited “product graduation” by users.

Conclusions:South African SLT users are mostly exposed to potentially very highly addictive levels of nicotine that may favour tobacco dependence and its consequent health risks. The increasing use of SLT by women of childbearing age support the need for intensified policy action to control its use.
ECONOMICS, ECONOMISTS, AND BEHAVIOURAL ECONOMICS: SOME ISSUES OF CHOICE
Authors: KNETSCH JACK L.
Published: May 2004

Economic behaviour observed in experiments and in people's everyday dealings is often at variance with predictions and explanations based on standard theory. The findings of systematic patterns of such economic behaviour provide significant opportunities to extend the usefulness of economics. However, like the hesitation of participants in economic experiments to give up their coffee mugs, economists appear reluctant to take advantage of these opportunities.
CREDIT RATING AND BANK BEHAVIOUR IN INDIA: POSSIBLE IMPLICATIONS OF THE NEW BASEL ACCORD
Authors: NACHANE D. M. , GHOSH SAIBAL
Published: May 2004

The paper examines the impact of credit rating on capital adequacy ratios of Indian state-owned banks using quarterly data for the period 1997:1 to 2002:4. To this end, a multinomial logit model with multi credit rating indicators as dependent variable is estimated. The variables that can impinge upon capital adequacy ratio have been used as explanatory variables. Two separate models — one for long-term credit rating and another for short-term credit rating — have been estimated. The paper concludes that, both for short-term as well as for long-term ratings, capital adequacy ratios are an important factor impinging on credit rating of Indian state-owned banks.
SOME EMPIRICAL EVIDENCE OF EXCHANGE MARKET PRESSURE IN SINGAPORE
Authors: AKIBA HIROYA , IIDA YUKIHIRO
Published: May 2004

This paper examines an intervention index in the foreign exchange market, applying the quarterly data of the Singapore economy during the 1990's. The intervention index measures intervention activity as the proportion of exchange market pressure relieved by exchange market intervention. Singapore is selected because (1) it is a small open economy and consistent with this empirical study, and (2) it has been affected by speculative attacks. The specific interest is the effectiveness of intervention conducted by the Singapore authority to mitigate exchange market pressure. It is concluded that the overall intervention activity is surprisingly successful over the sample period.
ON SINGAPORE DOLLAR–U.S. DOLLAR AND PURCHASING POWER PARITY
Authors: LIEW VENUS KHIM-SEN , BAHARUMSHAH AHMAD ZUBAIDI , LIM KIAN-PING
Published: May 2004

This study re-examines the validity of the relationship between the Singapore dollar–U.S. dollar exchange rate and relative prices using the latest econometric methodologies that account for non-linearity. Among others, this study finds Exponential Smooth Transition Autoregressive (ESTAR)-type non-linear mean-reverting adjustment process of the nominal Singapore dollar–U.S. dollar rate towards the consumer price index ratio. Unlike previous findings of a linear cointegration relationship between the nominal Singapore dollar–U.S. dollar exchange rate and consumer price index ratio, this study shows that the relationship is in fact non-linear in nature. The major economic implications of our findings are: (1) policy makers need to take non-linearity into consideration in their policy decisions; (2) the Monetary Authority of Singapore (MAS) is able to maintain the macroeconomic equilibrium despite the authority's strong dollar policy; and (3) one should keep track of Singapore's monetary policy and other innovations in aggregate demand in order to closely monitor the movement of the Singapore exchange rate.
STOCHASTIC FRONTIER ANALYSIS OF SINGAPORE MANUFACTURING INDUSTRIES
Authors: KOH SOO-WEI , RAHMAN SHAHIDUR , TAN G. K. RANDOLPH
Published: May 2004

Previous papers on Singapore manufacturing productivity have focused almost exclusively on total factor productivity (TFP) growth rates and ignored the problem of measuring the extent of learning-by-doing. In this paper, we examine an alternative measure: the rate of technical efficiency change. Using data from 1974–1998, a translog production frontier is estimated. Following a conceptual framework popularised by Bauer (1990), productivity growth is decomposed into components arising from technical progress, technical efficiency change, a scale economies effect and an allocative inefficiency effect.
HOMOGENIZATION OF TWO HEAT CONDUCTORS WITH AN INTERFACIAL CONTACT RESISTANCE
Authors: DONATO PATRIZIA , MONSURRÒ SARA
Published: May 2004

In this paper we describe the asymptotic behavior of a problem depending on a small parameter ε>0 and modelling the stationary heat diffusion in a two-component conductor. The flow of heat is proportional to the jump of the temperature field, due to a contact resistance on the interface.

More precisely, we give an homogenization result for the stationary heat equation with oscillating coefficients in a domain [Formula: see text] of ℝn, where [Formula: see text] is connected and [Formula: see text] is union of ε-periodic disconnected inclusions of size ε. These two sub-domains of Ω are separated by a contact surface Γε, on which we prescribe the continuity of the conormal derivatives and a jump of the solution proportional to the conormal derivative, by means of a function of order εγ.

We describe the limit problem for γ>-1. The two cases -1<γ≤1 (Theorem 2.1) and γ>1 (Theorem 2.2) need to be treated separately, because of different a priori estimates.
ON ISOMETRIC IMMERSIONS OF A RIEMANNIAN SPACE WITH LITTLE REGULARITY
Authors: MARDARE SORIN
Published: May 2004

We consider a Riemannian metric in an open subset of the d-dimensional Euclidean space and assume that its Riemann curvature tensor vanishes. If the metric is of class C2, a classical theorem in differential geometry asserts that the Riemannian space is locally isometrically immersed in the d-dimensional Euclidean space. We establish that if the metric belongs to the Sobolev space W1,∞ and its Riemann curvature tensor vanishes in the space of distributions, then the Riemannian space is still locally isometrically immersed in the d-dimensional Euclidean space.
INFINITE VALUED SOLUTIONS OF NON-UNIFORMLY ELLIPTIC PROBLEMS
Authors: BLANCHARD DOMINIQUE , GUIBÉ OLIVIER
Published: May 2004

We consider a quasilinear equation (see (1.1)) with L1 data and with a diffusion matrix A(x,u), which is not uniformly coercive with respect to u (see Assumptions (H3)–(H4)). Under such assumptions it is not realistic, in general, to search for a solution which is finite almost everywhere. We introduce two equivalent notions of solutions which take into account the possible values +∞ and -∞ (see Definitions 2.1 and 2.3). Then we prove that there exists at least one such solution. At last we establish an uniqueness result in the class of simultaneous infinite valued solutions.
AN ANALOGUE OF COWLING–PRICE'S THEOREM AND HARDY'S THEOREM FOR THE GENERALIZED FOURIER TRANSFORM ASSOCIATED WITH THE SPHERICAL MEAN OPERATOR
Authors: CHETTAOUI C. , OTHMANI Y. , TRIMÈCHE K.
Published: May 2004

Using the harmonic analysis associated with the spherical mean operator R and its dualtR we establish an analogue of Cowling–Price's theorem and Hardy's theorem for the spherical mean operator R.
Molecular Characterization of the Essential Response Regulator Protein YycF in Bacillus subtilis
Authors: Watanabe Takafumi , Hashimoto Yoshiki , Umemoto Yoshihito , Tatebe Daisuke , Furuta Eiji , Fukamizo Tamo , Yamamoto Kaneyoshi , Utsumi Ryutaro
Published: May 2004

The response regulator YycF is essential for cell growth in gram-positive bacteria including Bacillus subtilis, Staphylococcus aureus and Streptococcus pneumoniae. To study the function of YycF in the essential process, we characterized a YycF (H215P) mutation that caused temperature-sensitive growth in B. subtilis. The response regulators YycF and YycF (H215P) were analyzed using circular dichroism spectroscopy, whose Tm values were 56.0 and 45.9°C, respectively, suggesting that YycF (H215P) significantly affects the protein structure with an increase in temperature. Furthermore, using the gel mobility shift assay and DNase I footprinting, we investigated the effect of YycF (H215P) on binding to the YycF box of ftsAZ operon of B. subtilis. The replacement of the histidine 215 with proline resulted in a decrease of the DNA-binding ability of YycF in vitro. In vivo, using Escherichia coli two-hybrid and homodimerization assays, we clarified that His 215 of YycF plays a crucial role in the homodimerization of the protein. Thus the essential genes involved in growth of B. subtilis appear to be regulated by the homodimer of YycF. These results suggest that the YycF dimerization is an excellent target for the discovery of novel antibiotics.
Heat Shock (σ32 and HrcA/CIRCE) Regulons in β-, γ- and ε-Proteobacteria
Authors: Permina E.A. , Gelfand M.S.
Published: May 2004

During heat shock, the main strategy of an organism is defense from denatured proteins. This is performed by chaperones that refold and proteases that cut abnormal proteins. In studying the σ32 and HrcA regulons in β- and γ-proteobacteria, we have found some new potential participants in the heat shock response and proposed the protein disulfide isomerase function for one of them. We describe the connection between the two regulons through cross-regulation of the HrcA repressor and σ32 in some β-proteobacteria. Finally, we predict the binding signal for HrcA in Ε-proteobacteria.
Lipopolysaccharide O-Antigen Antibody-Based Detection of the Fish Pathogen Flavobacterium psychrophilum
Authors: Crump Elizabeth M. , Perry Malcolm B. , Gale Stephen , Crawford Evan , Kay William W.
Published: May 2004

Several yellow-pigmented species within the family Flavobacteriaceae are commonly associated with diseases in fish and are difficult to speciate due to their fastidious, slow-growing nature and cross-reactive antigens. Here we report the development of specific, antibody-diagnostic tests for Flavobacterium psychrophilum, the aetiological agent of rainbow trout fry syndrome and bacterial cold water disease. A unique antigen from F. psychrophilum, the lipopolysaccharide (LPS) O-polysaccharide (O-PS), formed the basis for the antibody test. LPS O-PS was purified and conjugated to keyhole limpet haemocyanin and bovine serum albumin for the generation of rabbit immune sera and the development of antibody-based diagnostic tests. Rabbit polyclonal anti-O-PS serum was highly specific for F. psychrophilum, without the need for prior cross-absorption with related bacteria and was the basis of an effective ELISA diagnostic test. Antibodies were purified from rabbit anti-O-PS serum and adsorbed onto coloured latex beads for the development of a specific, bead agglutination assay for F. psychrophilum.
Divergent Promoter Organization May Be a Preferred Structure for Gene Control in Escherichia coli
Authors: Yamada Mamoru , Kabir Md. Shahinur , Tsunedomi Ryouichi
Published: May 2004

The prokaryote possesses intriguing promoter arrangements called divergent promoters, which transcribe adjacent genes in opposite directions. The genome analysis in Escherichia coli revealed the occurrence of a large number of divergent promoters, whose total number was estimated to be about 1.6-fold larger than that of single promoters. Surprisingly, more than 65% divergent promoters transcribe functionally unrelated genes. Transcription from one promoter has been proposed and demonstrated to influence that from the other promoter via change in superhelicity in the divergent promoter region. Therefore, the organism may have acquired divergent promoters as a common structure for ingenious gene controls including transcription coupling.
Eukaryotic Promoters Can Direct Protein Synthesis in Gram-Negative Bacteria
Authors: Goussard Sylvie , Grillot-Courvalin Catherine , Courvalin Patrice
Published: May 2004

Intracellular bacteria can act as DNA delivery vectors into mammalian cells. Transfer of genetic information can be monitored by screening for cellular expression of a reporter gene under the control of an eukaryotic promoter. However, intracellular bacteria can also efficiently deliver heterologous proteins in the cell cytosol. We have studied the activity of the eukaryotic PCMV promoter in Escherichia coli and Salmonellatyphimurium using the lacZ and gfp genes as reporters and determined its strength relative to those of PRSV and PSV40 in E. coli. We found substantial heterologous activity of fragments carrying the PCMV and PRSV promoters, the strength of PRSV being greater than that of PCMV, but did not detect any PSV40 activity in E. coli. The green fluorescent protein (GFP) synthesized in E. coli was transferred to COS-1 cells where it was detectable and stable. Insertion of a transcription terminator or deletion of the bacterial ribosome binding site downstream from PCMV led to the silencing of the promoter in bacteria but not in mammalian cells. These observations should incite to exert caution when interpreting data on the DNA transfer from bacteria to mammallian cells when the genes of interest are under the control of the PCMV or PRSV promoter.
Effect of Dexamethasone on Tracheobronchial Aspirate Fluid Cytology and Pulmonary Mechanics in Preterm Infants
Authors: Vento G. , Matassa P.G. , Zecca E. , Tortorolo L. , Martelli M. , De Carolis M.P. , Maggio L. , Zini G. , d’Onofrio G. , Valentini S. , Romagnoli C.
Published: May 2004

The changes induced on respiratory mechanics and on tracheobronchial aspirate fluid (TAF) cytology by dexamethasone courses started at two different postnatal ages in preterm infants at risk of chronic lung disease (CLD) were reported in this clinical trial designed in two phases. The first phase of the study included 20 neonates with birth weight ≤1,250 g and gestational age ≤32 weeks, who were oxygen and ventilator dependent on the 10th day of life. They were randomly assigned to the moderately early dexamethasone (MED) group or to the control group. The second phase of the study included 20 neonates with the same characteristics, oxygen and ventilator dependent on the 4th day of life, randomly assigned to the early dexamethasone (ED) group or to the control group. Both treated groups received dexamethasone intravenously for 7 days (0.5 mg/kg/day for the first 3 days, 0.25 mg/kg/day for the next 3 days, and 0.125 mg/kg/day for the last day of treatment). The control groups received no steroid treatment. A significantly lower absolute cell count and percentage of neutrophils (PMN) in the TAF and significantly higher dynamic lung compliance (Cdyn) values were observed in both the MED treated compared to the untreated infants and the ED treated infants compared to the control group. Moreover these changes were more precocious in the ED Group compared to the MED Group. Our study suggests that dexamethasone could be more efficacious in reducing effects of ventilator-induced lung injury in preterm infants at high risk of CLD when started earlier.
Effects of Melatonin on Impaired Neurogenic and Endothelial Relaxations by Bacterial Lipopolysaccharide in the Mouse Corpus cavernosum
Authors: Kumcu Eda Karabal , Büyüknacar H. Sinem Göktürk , Kiroğlu Olcay Ergürhan , Göçmen Cemil , Döndaş Naciye , Dikmen Atilla
Published: May 2004

We investigated whether bacterial lipopolysaccharide treatment causes any neuronal and vascular hyporeactivity in mouse cavernous tissue and also whether melatonin has any restorative effect on this possible neuronal and vascular hyporesponsiveness. Lipopolysaccharide treatment attenuated contractions in response to phenylephrine. Treatment with the inducible nitric oxide synthase inhibitor aminoguanidine or melatonin restored the hypocontractility of the cavernous smooth muscle to phenylephrine. Relaxant responses of corpus cavernosum precontracted by phenylephrine to acetylcholine or electrical field stimulation were significantly impaired in mice treated with bacterial lipopolysaccharide. Treatment with aminoguanidine or melatonin could prevent the impairment of the neuronal and endothelial relaxations. There was no significant difference between control and lipopolysaccharide-treated groups in the contractile response to high-dose KCl and in the relaxant response to papaverine. In conclusion, bacterial lipopolysaccharide treatment caused a neuronal and endothelial dysfunction in the mouse corpus cavernosum. A possible increased oxidative activity in the cavernous tissue may be a major reason for the impairment of relaxant responses and hypocontracility of tissue. The restorative effects of melatonin on this hyporeactivity may depend on its antioxidant properties and partly on its inhibitory action on the inducible nitric oxide synthase production.
Effect of COX-1/COX-2 Inhibition versus Selective COX-2 Inhibition on Coronary Vasodilator Responses to Arachidonic Acid and Acetylcholine
Authors: Gross Garrett J. , Moore Jeannine
Published: May 2004

The effect of a nonselective COX-1/COX-2 inhibitor, naproxen, was compared with a COX-2-selective inhibitor (SC-58236) on coronary vasodilatory responses in the anesthetized dog. Coronary vasodilation was induced by direct intracoronary injection of acetylcholine (ACH) and arachidonic acid (AA) in control animals and in those treated with either naproxen (1, 3, or 10 mg/kg p.o. 24 h prior to the experiment) or SC-58236 (1, 5, or 15 mg/kg p.o. 24 h prior to the experiment). Naproxen, at 10 mg/kg, significantly attenuated the AA-induced vasodilation (prostacyclin dependent) with no effect on ACH-induced vasodilation (nitric oxide dependent). SC-58236 failed to attenuate either AA- or ACH-induced vasodilation. Ex vivo assays were utilized to establish inhibition of COX-2 (lipopolysaccharide-stimulated prostaglandin E2 formation) and COX-1 (serum thromboxane B2) in blood taken from dogs administered 1, 3, or 10 mg/kg naproxen or 15 mg/kg SC-58236. Naproxen (3 and10 mg/kg) and SC-58236 (15 mg/kg) markedly reduced the lipopolysaccharide-induced prostaglandin E2 formation, whereas SC- 58236 (15 mg/kg) had no effect on serum thromboxane B2. Naproxen significantly reduced thromboxane B2 at all three doses studied. Furthermore, naproxen (10 mg/kg p.o.) significantly inhibited the AA-induced platelet aggregation (thromboxane B2 dependent), whereas SC-58236 had no effect. Collectively, these results demonstrate that SC-58236 is selective for COX-2, while naproxen is a nonselective inhibitor. These data also suggest that vasodilatory responses to AA in the dog are primarily COX-1 dependent. Selective COX-2 inhibition does not affect either prostacyclin or nitric oxide mediated vasodilation in the canine coronary circulation.
Transdermal Eperisone Elicits more Potent and Longer-Lasting Muscle Relaxation than Oral Eperisone
Authors: Yang Sang-In , Park Ha-Young , Lee Sang-Ho , Lee Seung-Jin , Han Ok-Yeun , Lim Sung-Cil , Jang Choon-Gon , Lee Wan-Suk , Shin Young-Hee , Kim Jung-Ju , Lee Seok-Yong
Published: May 2004

Eperisone hydrochloride is widely used for the treatment of plasticity to relieve muscle stiffness and back pain. However, oral eperisone has a very low bioavailability and short muscle relaxant activity, because of the profound intestinal first-pass metabolism. To improve the efficacy and compliance of eperisone, we designed a new dosage form, a transdermal patch, and evaluated the efficacy of the eperisone patch with the muscle relaxant activity of rats. The muscle relaxant activity was assessed by the measurement of forelimb grip strength and hanging test in rats. The transdermal patch of eperisone showed significantly enhanced muscle relaxant activity at 0.5 1.5 and 3 cm2/200 g rat (1.39, 4.17 and 8.33 mg of eperisone hydrochloride/kg, respectively) in a dose-dependent manner and the effects lasted over 24 h. Even though oral eperisone hydrochloride showed significant muscle relaxant activity at 12.5, 25 and 50 mg/kg in a dose-dependent manner, the activity lasted only 1 or 2 h after administration. These results suggest that eperisone as transdermal patch form showed efficient absorption with more potent and longer-lasting muscle relaxant activity than oral solution. The transdermal patch form of eperisone will increase the efficacy and compliance in the clinical use of eperisone.
Cabergoline Stimulates Synthesis and Secretion of Nerve Growth Factor, Brain-Derived Neurotrophic Factor and Glial Cell Line-Derived Neurotrophic Factor by Mouse Astrocytes in Primary Culture
Authors: Ohta Kiyoe , Fujinami Aya , Kuno Sadako , Sakakimoto Asuka , Matsui Hidehito , Kawahara Yuji , Ohta Mitsuhiro
Published: May 2004

Neuroprotection is the primary concern in patients with newly diagnosed Parkinson’s disease. The D2/weak D1 dopamine agonist cabergoline elicits neuroprotection by antioxidation and scavenging free radicals, and may protect neurons by up-regulating endogenous neurotrophic factors synthesis in the brain. In primary cultured mouse astrocytes, cabergoline 37 µmol/l immediately elevated concentrations of nerve growth factor, brain-derived neurotrophic factor, and glial cell line-derived neurotrophic factor (GDNF) in culture medium, reaching 9.9-, 2.6- and 30-fold, respectively, of control levels at 16 h. Relative mRNA levels were 3.0-, 1.5- and 1.9-fold, respectively, of controls at 3 h. These effects may be mediated partly by the dopamine D2 receptor. Cabergoline may be a good candidate for an inducer of GDNF, which may have neuroprotective and neurorestorative properties in dopaminergic nigral neurons.
Pathways of DNA double-strand break repair and their impact on the prevention and formation of chromosomal aberrations
Authors: Pfeiffer P. , Goedecke W. , Kuhfittig-Kulle S. , Obe G.
Published: May 2004

DNA double-strand breaks (DSB) are considered the critical primary lesion in the formation of chromosomal aberrations (CA). DSB occur spontaneously during the cell cycle and are induced by a variety of exogenous agents such as ionising radiation. To combat this potentially lethal damage, two related repair pathways, namely homologous recombination (HR) and non-homologous DNA end joining (NHEJ), have evolved, both of which are well conserved from bacteria to humans. Depending on the pathway used, the underlying mechanisms are capable of eliminating DSB without alterations to the original genomic sequence (error-free) but also may induce small scale mutations (base pair substitutions, deletions and/or insertions) and gross CA (error-prone). In this paper, we review the major pathways of DSB-repair, the proteins involved therein and their impact on the prevention of CA formation and carcinogenesis.
Recombination repair pathway in the maintenance of chromosomal integrity against DNA interstrand crosslinks
Authors: Sasaki M.S. , Takata M. , Sonoda E. , Tachibana A. , Takeda S.
Published: May 2004

DNA interstrand crosslinks (ICL) present a major threat to cell viability and genome integrity. In eukaryotic cells, the ICLs have been suggested to be repaired by a complex process involving Xpf/Ercc1-mediated endonucleolytic incision and homologous recombination (HR). However, the entire feature of the ICL tolerating mechanism is still poorly understood. Here we studied chromosome aberrations (CA) and sister chromatid exchanges (SCE) by the use of the crosslinking agent mitomycin C (MMC), in chicken DT40 cells with the HR genes disrupted by targeted replacement. The disruption of the Rad54, Rad51B, Rad51C, Rad51D, Xrcc2 and Xrcc3 genes resulted in a dramatic reduction of spontaneous and MMC-induced SCEs. Interestingly, while HR-deficient cells were hypersensitive to cell killing by MMC, MMC-induced CAs were also suppressed in the HR-deficient cells except for Rad51D-, Xrcc2- and Xrcc3-deficient cells. These observations indicate that DNA double strand breaks (DSB) at stalled replication forks and those arising as repair intermediates present strong signals to cell death but can be tolerated by the HR repair pathway, where Rad54, Rad51B and Rad51C have an initiative role and repair can be completed by their paralogs Rad51D, Xrcc2 and Xrcc3. The impairment of the HR pathway, which otherwise leads to cell death, may be somewhat substituted by an alternative mechanism such as the Mre11/Rad50/Nbs1 pathway, resulting in reduced frequencies of SCEs and CAs.
On the nature of visible chromosomal gaps and breaks
Authors: Savage J.R.K.
Published: May 2004

From the earliest days of chromosomal aberration studies, the distinction, nature and origin of light-microscope observed “gaps” and “breaks” have been topics for debate and controversy. In this paper we survey, briefly, the various ideas that have appeared in the very extensive literature, and attempt to evaluate them in the light of our current understanding of chromosome structure and aberration formation. Attention is drawn to the problems of interpretation caused by G2/S cell imprecision.
Molecular targets and mechanisms in formation of chromosomal aberrations: contributions of Soviet scientists
Authors: Belyaev I.
Published: May 2004

Studies of mechanisms for formation of chromosomal aberrations (CAs) with special emphasis on data from Soviet/Russian investigations are reviewed that argue in favor of a minor fraction of genomic DNA that forms specific molecular targets/contacts for the formation of chromosomal exchanges. This DNA is presumably associated with matrix attachment sites of DNA loops, enriched with AT base pairs and repetitive DNA sequences. It is assumed that there are two main mechanisms in formation of chromosome aberrations: 1) mutually reciprocal recombination, resulting in formation of all kinds of chromosome exchanges; 2) the process of telomere formation, resulting in the generation of true deletions. A significant part of chromosomal breaks and apparently unrejoined ends in incomplete exchanges as seen with cytogenetic techniques reflect decondensation in the discrete units of chromatin organization such as the megabase-size DNA domains. The possible ways for further analysis of alternative theories with emerging technologies are also discussed.
Human-hamster hybrid cells used as models to investigate species-specific factors modulating the efficiency of repair of UV-induced DNA damage
Authors: Marcon F. , Boei J.J .W.A. , Natarajan A.T.
Published: May 2004

The human-Chinese hamster hybrid cell line XR-C1#8, containing human chromosome 8, was used as a model system to investigate the relative importance of cellular enzymatic environment and chromosomal structure for modulating the efficiency of repair of UV-induced DNA damage. The hybrid cells were irradiated with UVC light and the extent of cytogenetic damage, detected as frequencies of sister chromatid exchanges (SCEs), was compared between the human and the hamster chromosomes. The combination of immunofluorescent staining for SCEs and chromosome painting with fluorescence in situ hybridization allowed the simultaneous analysis of SCEs in the human and hamster chromosomes. The aim of the present study was to determine if the differences in biological response to comparable UV treatments observed between human and hamster cells were maintained in the hybrid cells in which human and hamster chromosomes are exposed in the same cellular environment. The analysis of replication time of human chromosome 8 indicated the active status of this chromosome in XR-C1#8 hybrid cells. The frequencies of SCEs for human chromosome 8 and a hamster chromosome of comparable size were 0.35 ± 0.52, 0.80 ± 0.73, 1.24 ± 2.24 and 0.36 ± 0.12, 0.71 ± 0.2, 0.97 ± 0.27, respectively, after irradiation with 0, 5, and 10 J/m2. The persistence of UV-induced SCEs after three cell cycles was also analyzed, both for the human and hamster chromosomes. The observed frequencies of SCEs were 0.40 ± 0.57, 0.62 ± 1.05, 0.58 ± 0.83 and 0.26 ± 0.08, 0.67 ± 0.18, 0.69 ± 0.24, in human and hamster chromosomes respectively, after treatment with 0, 10, and 20 J/m2 of UVC light. No significant differences could be observed between the human and hamster chromosomes. These results suggest that the enzymatic environment of human and hamster cells has the main role, in comparison to the structural organization of human and hamster chromosomes, for determining the different level of repair of UV-induced DNA damage observed in these two species.