bluuebunny/crossref_metadata_2025 huggingface dataset:
New CsCl-Type Intermediate Phases in Binary Alloys Involving Rare-Earth Elements
Authors: Chao C. C. , Duwez P.
Published: April 2005

To further work on intermediate phases having the CsCl-type structure in binary alloys involving one rare earth, fifteen additional phases in alloys of rare earths with Zn, Cd, Hg, In, and Tl are described in this paper.
Probe Measurements in a Pulsed Plasma: Experimental Verification of the BBM Analysis for Ion Saturation Current
Authors: Hosea J. C.
Published: April 2005

A technique of probe measurement is given which allows an easy determination of Langmuir probe curves in a reproducible pulsed plasma. The technique is then used to study a pulsed P.I.G. reflex discharge. Experimental probe curves are analyzed with a theory based on the BBM formula for ion saturation current. Comparison of probe measurements of electron density with the measurements of an 8.5-mm interferometer shows that the probe behavior is properly described by the Langmuir-BBM (Bohm, Burhop, Massey) theory. Also as predicted theoretically, the experimental ratio of floating potential to electron temperature is shown to be reasonably constant over wide variations in plasma parameters.
Combined Anode-Cathode Feed of a Hollow-Cathode Arc
Authors: Gerry E. T. , Rose D. J.
Published: April 2005

A simple recipe is given for separating the anode and cathode regions of a hollow-cathode-arc plasma by a baffle and introducing a small gas feed through the hollow anode. By this stratagem, the anode-region plasma can be tailored within wide limits for ion species and density, and degree of ionization. For example, a 95% pure hydrogen plasma with ion density 1013–1014 cm−3, 90% ionized, can be produced at low voltage, with the cathode running under ideal conditions in argon.
Electrostatic Atomization and Spray Painting
Authors: Hines R. L.
Published: April 2005

The phenomenon of electrostatic atomization and the process of electrostatic spray painting are analyzed to show the role of the various physical parameters. The charging and atomization of an individual fluid jet in an electrostatic field are investigated in detail. Experimental data are presented for various quantities such as drop size and charge per unit mass of drops under typical conditions of electrostatic painting and also for single jets. Approximate formulas are given which relate these quantities to the fluid properties and the electrical fields in the system.
Optical Experiments with a Magnetically Rotatable Diffraction Grating
Authors: Cohler Edmund U. , Rubinstein Harvey , Jones Carolyn
Published: April 2005

A striped-domain thin magnetic film, when covered by a Bitter colloid, forms a diffraction grating. Because of its possible application in display devices this phenomenon is attracting current interest. The theory of the grating formation is developed, and it is shown that external fields can and do greatly improve the grating configuration and efficiency. Improvements in diffracted light flux efficiency of as much as four to one have been observed.
Diffraction by a Half-Plane Perpendicular to the Distinguished Axis of a Uniaxially Anisotropic Medium
Authors: Przeździecki S.
Published: April 2005

The solution to the three-dimensional problem of diffraction of a plane electromagnetic wave by a perfectly conducting half-plane embedded in a uniaxially anisotropic medium perpendicularly to the distinguished axis of the medium is presented.

A fundamental feature of the considered problem is its essentially vectorial character, i.e., its solution cannot be reduced to solving one scalar boundary-value problem for one function satisfying its second-order equation.

The solution has been constructed via a synthesis of the solutions to appropriate auxiliary scalar half-plane diffraction problems for two distinct wave equations. In connection with these auxiliary problems an examination of diffraction of inhomogeneous plane waves by a half-plane proved necessary.

A general approach to analysis of electromagnetic fields in uniaxially anisotropic media by splitting them into two component fields of TE and TM type with respect to the distinguished axis of the medium has been summarized in the form of a theorem.
Enhanced Tunneling through Dielectric Films due to Ionic Defects
Authors: Schmidlin Fred W.
Published: April 2005

The theoretical shape of the potential barrier for a dielectric film interposed between two metals is discussed, with particular emphasis on the effects arising from ionic defects, interfacial dipoles, and field penetration of the electrodes. It is shown that both ions and the extension of their electric fields penetrating the electrodes have a significant effect on barrier shape. By applying Stratton's theory of tunneling, an analytic expression is obtained for the increase of tunnel current due to ion penetration of the barrier. For ion concentrations of the order of one per unit area equal to the film thickness square, the tunnel current increases by an order of magnitude. Numerical results are also presented for an Al–Al2O3–Al barrier, where the analytic solution is only marginally valid.
Temperature Dependence of Sputtering Yields of Ge (100) and (110) Surfaces
Authors: Anderson G. S.
Published: April 2005

The temperature dependence of sputtering yields of Ge (100) and (110) under low-energy Ne+ and Ar+ ion bombardment has been investigated. For target temperatures above the annealing temperature Ta where atom ejection patterns are observed, yield differences up to 50% are noted. For target temperatures below Ta the sputtering yield is independent of the crystallographic surface. Furthermore, this yield is less than the high-temperature yield for the (100) surface and higher than the high-temperature yield for the (110) surface.
Strain Energy of a Kink
Authors: Brailsford A. D.
Published: April 2005

The strain energy of a kink in a dislocation is calculated using a newly developed approach to problems involving stationary dislocations. The method is based upon linear elasticity theory supplemented by the use of a Debye cutoff in momentum space, the latter being introduced to account for the finite number of degrees of freedom of real solids. Numerical results are given for Al, the noble metals, and for Nb. These are compared with the experimentally determined activation energies associated with the Bordoni internal friction peaks. The calculated values for kinks in screw dislocations, in the metals considered, are found to exceed the experimental values by not more than 66%.
Nucleation in Polymer Crystallization and its Relevance to the Morphology of Polyethylene Single Crystals
Authors: Burns Joanne R.
Published: April 2005

An atomistic model has been proposed for the two- and three-dimensional nucleation of polymer crystallization. This model emphasizes the restrictions placed on the shape of the nuclei by the long chain nature of the polymer. The experimental observations by Cormia, Price, and Turnbull of the homogeneous nucleation of polyethylene droplets are analyzed using the model, and it is found that the end surface energy σe=96.4 erg/cm2. It is also shown that the model for two-dimensional surface nucleation explains the temperature dependence of the morphology of polyethylene single crystals grown from dilute solutions in xylene and octane.
High-Voltage Electron Microscopy
Authors: Bahr G. F. , Zeitler E. H. , Kobayashi K.
Published: April 2005

An increase of the acceleration voltage in conventional transmission microscopy yields reduced damage to the specimen and a potentially higher resolving power, and permits an increase in specimen thickness. These gains as a function of voltage are discussed and partly confirmed by experiments. The differential gains above 500 kV are very small, yet costly. A range up to 1000 kV for conventional high-voltage electron microscopy can be recommended.
A specific subdomain in φ29 DNA polymerase confers both processivity and strand-displacement capacity
Authors: Rodríguez Irene , Lázaro José M. , Blanco Luis , Kamtekar Satwik , Berman Andrea J. , Wang Jimin , Steitz Thomas A. , Salas Margarita , de Vega Miguel
Published: April 2005

Recent crystallographic studies of φ29 DNA polymerase have provided structural insights into its strand displacement and processivity. A specific insertion named terminal protein region 2 (TPR2), present only in protein-primed DNA polymerases, together with the exonuclease, thumb, and palm subdomains, forms two tori capable of interacting with DNA. To analyze the functional role of this insertion, we constructed a φ29 DNA polymerase deletion mutant lacking TPR2 amino acid residues Asp-398 to Glu-420. Biochemical analysis of the mutant DNA polymerase indicates that its DNA-binding capacity is diminished, drastically decreasing its processivity. In addition, removal of the TPR2 insertion abolishes the intrinsic capacity of φ29 DNA polymerase to perform strand displacement coupled to DNA synthesis. Therefore, the biochemical results described here directly demonstrate that TPR2 plays a critical role in strand displacement and processivity.
Groups of units of integral group rings of Kleinian type
Authors: Pita Antonio , del Río Ángel , Ruiz Manuel
Published: April 2005

We explore a method to obtain presentations of the group of units of an integral group ring of some finite groups by using methods on Kleinian groups. We classify the nilpotent finite groups with central commutator for which the method works and apply the method for two concrete groups of order 16.
Spike-layered solutions for an elliptic system with Neumann boundary conditions
Authors: Ramos Miguel , Yang Jianfu
Published: April 2005

We prove the existence of nonconstant positive solutions for a system of the form−ε2Δu+u=g(v)-\varepsilon ^2\Delta u + u = g(v),−ε2Δv+v=f(u)-\varepsilon ^2\Delta v + v = f(u)inΩ\Omega, with Neumann boundary conditions on∂Ω\partial \Omega, whereΩ\Omegais a smooth bounded domain andff,ggare power-type nonlinearities having superlinear and subcritical growth at infinity. For small values ofε\varepsilon, the corresponding solutionsuεu_{\varepsilon }andvεv_{\varepsilon }admit a unique maximum point which is located at the boundary ofΩ\Omega.
Seshadri constants at very general points
Authors: Nakamaye Michael
Published: April 2005

We study the local positivity of an ample line bundle at a very general point of a smooth projective variety. We obtain a slight improvement of the result of Ein, Küchle, and Lazarsfeld.
Entire solutions of certain partial differential equations and factorization of partial derivatives
Authors: Li Bao
Published: April 2005

We show that the problem of characterizing entire solutions of certain partial differential equations and the problem of characterizing common right factors of partial derivatives of meromorphic functions in

C

2

\mathbf {C}^{2}

are closely related, and characterizations will be given using their relations.
Mixing times of the biased card shuffling and the asymmetric exclusion process
Authors: Benjamini Itai , Berger Noam , Hoffman Christopher , Mossel Elchanan
Published: April 2005

Consider the following method of card shuffling. Start with a deck of

N
N

cards numbered 1 through

N
N

. Fix a parameter

p
p

between 0 and 1. In this model a “shuffle” consists of uniformly selecting a pair of adjacent cards and then flipping a coin that is heads with probability

p
p

. If the coin comes up heads, then we arrange the two cards so that the lower-numbered card comes before the higher-numbered card. If the coin comes up tails, then we arrange the cards with the higher-numbered card first. In this paper we prove that for all

p
≠
1

/

2

p\ne 1/2

, the mixing time of this card shuffling is

O
(

N
2

)

O(N^2)

, as conjectured by Diaconis and Ram (2000). Our result is a rare case of an exact estimate for the convergence rate of the Metropolis algorithm. A novel feature of our proof is that the analysis of an infinite (asymmetric exclusion) process plays an essential role in bounding the mixing time of a finite process.
On compact symplectic manifolds with Lie group symmetries
Authors: Guan Daniel
Published: April 2005

In this note we give a structure theorem for a finite-dimensional subgroup of the automorphism group of a compact symplectic manifold. An application of this result is a simpler and more transparent proof of the classification of compact homogeneous spaces with invariant symplectic structures. We also give another proof of the classification from the general theory of compact homogeneous spaces which leads us to a splitting conjecture on compact homogeneous spaces with symplectic structures (which are not necessary invariant under the group action) that makes the classification of this kind of manifold possible.
IT Alignment in Supply Chain Relationships: A Study of Supplier Benefits
Authors: Sanders Nada R.
Published: April 2005

Deployment of interorganizational information technology (IT) throughout supply chain networks has usually been championed by supply chain network leaders — large firms that typically dominate a supply chain network. In order to participate in a particular network, supplier firms must acquire the requisite IT enabling them to be technologically aligned with the network leader. This is an important decision for supplier firms that are typically smaller in size and must allocate larger portions of their budgets to acquire the necessary IT. This study evaluates the benefits gained by suppliers when investing in interorganizational IT that is aligned with their primary buyer or network leader. The findings show that IT alignment between supplier and buyer has a direct positive impact on both strategic and operational performance measures of the supplier. In addition, IT alignment impacts these performance measures indirectly as it encourages integration between firms.
Temporal patterns in a fish assemblage of a semiarid mangrove zone in Madagascar
Authors: Laroche J. , Baran E. , Rasoanandrasana N. B.
Published: April 2005

Gillnet sampling was conducted for a year in a tropical mangrove creek (SW Madagascar), characterized by a limited freshwater influence, a high turbidity and a tidal range up to 3 m. Sixty species of juvenile fishes were caught, 44 species being of commercial interest. Catches were dominated by Gerreidae (27% of total abundance), Teraponidae (16%), Carangidae (13%) and Sparidae (12%). The temporary resident fishes in the mangrove zone represented 50% of the species and 97% of the total abundance, the other species being rare (less than five individuals). The species richness, abundance and biomass per netting were low in the middle of the cool season (July‐August). Monthly changes in the fish assemblage were particularly complex, with three species groups displaying a clear seasonal pattern, some species succeeding one another in a rather unstructured way, and three species abundant throughout the year. There was no clear structuring effect of temperature, salinity and turbidity on the fish assemblage. However, tidal, lunar and diel effects on the composition of the fish assemblage were evident. The species overlap between the Sarodrano mangrove fauna and the adjacent coral reef fauna is particularly weak with six species in common and shows that the mangrove plays only a very limited nursery role for coral reef species.
Genetic relationships among populations of wild resident, and wild and hatchery anadromous brook charr
Authors: Jones M. W. , Danzmann R. G. , Clay D.
Published: April 2005

To determine the genetic relationship of anadromous and resident life‐history types within and among drainages, and compare several hatchery strains to their progenitor populations, brook charr Salvelinus fontinalis were examined for allozyme and mitochondrial DNA variation. Greater genetic similarity of sympatric anadromous and resident charr was found compared to similar life‐history forms allopatrically, suggesting the two life‐history types are not reproductively isolated. Low divergence among the mtDNA haplotypes suggests that the two life‐history types are members of the same evolutionary lineage. Population differentiation from mtDNA data exceeded that from estimates based on allozymes. Genetic deviations from expectations suggest that the hatchery strains were derived from few individuals.
Habitat use by the fish assemblages of two chalk streams
Authors: Prenda J. , Armitage P. D. , Grayston A.
Published: April 2005

Patterns of habitat use by fish assemblages in two chalk streams in southern England were examined to identify species preferences with respect to major habitat gradients. Both study sites, although differing in some physical habitat characteristics, mainly channel width, water temperature and instream cover, could be arranged similarly along a continuum extending from erosional to depositional habitats. Twelve fish species were collected from stream surveys conducted during July 1993. The habitat was partitioned into six fish species associations that could be assigned to three habitat guilds: depositional (Barbatula barbatula, Gasterosteus aculeatus and Anguilla anguilla), riffle (Leuciscus leuciscus, Thymallus thymallus and Salmo salar) and generalist (Salmo trutta, Phoxinus phoxinus, Gobio gobio, Cottus gobio, Lampetra planeri and Pleuronectes flesus). At low to moderate densities the different species associations were collected in the same habitat patch, but at higher densities there was a clear tendency to mutual avoidance. In particular, large trout appeared as strong interactors that tended to exclude other species from their territories. It is hypothesized that the fish assemblage of the Mill Stream and Bere Stream have partitioned the habitat in such a way as to minimize potential Competition.
Use of seasonally flooded marshes by fish in a Mediterranean wetland: timing and demographic consequences
Authors: Poizat G. , Corivelli A. J.
Published: April 2005

In the Camargue (southern France), movements of fish between a canal and two seasonally flooded marshes were monitored continuously by fish traps for 3 years for one marsh and for 2 years for the other. The timing of the entry and exit of the main species was determined together with species annual demographic balance, defined as the difference between the number of fish leaving and the number of fish entering. Only some of the species inhabiting the canal colonized the marshes. Except those species that reproduced in salt or brackish waters, all the species colonizing the marshes reproduced in it. The most abundant of these species were small sized (mosquitofish, sand smelt and three‐spined stickleback). The unpredictability of water levels in summer was particularly unfavourable for recruitment and survival of species that breed late in the year, e.g. pumpkinseed sunfish, or which prolonged their stay in the marsh and only attempted to leave just before the connection was broken, e.g. carp. Only the three‐spined stickleback always had a positive demographic balance as a result of colonizing the marshes. Adults of this species entered in winter and young‐of‐the‐year left in April. By limiting its stay in the seasonally flooded marshes, the stickleback minimized the risks related to environmental unpredictability. These results suggest that hydrology (temporal variations of water depth) may influence the fish community structure through interspecific differences in survival and recruitment, as a result of temporal variations in the use of seasonally flooded marshes.
Interannual variation in condition of the mackerel icefish
Authors: Everson I. , Kock K.‐H. , Parkes G.
Published: April 2005

Mackerel icefish Champsocephalus gunnari are widespread on the South Georgia (54° S, 36° W) shelf. Analysis of condition indicated a strong interannual variation. High condition indices, indicative of good feeding conditions, were present when krill were abundant in the region. Years when krill were scarce and condition index was consequently low, were consistent with years when indices from land‐based krill predators also indicated that krill were scarce.
First events in lipid absorption during post‐embryonic development of the anterior intestine in gilt‐head sea bream
Authors: Diaz J. P. , Guyot E. , Vigierand S. , Connes R.
Published: April 2005

Structural development and lipid absorption in anterior intestine of gilt‐head sea bream Sparus aurata, were studied by light and electron microscopy during three stages of post‐embryonic development: (1) the endotrophic period from hatching day (day 0) to mouth opening day (day 3); (2) the endo‐exotrophic period from days 3 to 15; (3) the exotrophic period after day 15. During the 2 days following hatching, there was no trace of lipids in intestinal epithelia. Before mouth opening day, the first lipoproteic particles of endogenous origin appeared in enterocyte endoplasmic reticulum and Golgi apparatus. During the endo‐exotrophic period, lipoproteinogenesis increased weakly until day 9, and more greatly between days 9 and 15. It intensified at the beginning of the exotrophic period to remain at a high level afterwards. Until day 15, few transfers of lipoproteins to interenterocyte spaces occurred, whereas no lipoproteins were detectable in the blood flow from days 7 to 9. Their concentration increased slightly between days 9 and 15 to become intense afterwards. Lipid droplets appeared from day 7, and subsisted until the end of endo‐exotrophic period. Possible relationships between very low density lipoproteins and chylomicron type lipoproteins and lipid droplets related to lipid excess in food are discussed.
Identification of Anguilla japonica and A. mavmovata elvers by allozyme electrophoresis
Authors: Lee S. C. , Tsoi S. C. M. , Cheng H. L. , Chang J. T.
Published: April 2005

In Taiwanese waters, the morphologically similar elvers ofAnguilla japonica and A. marmorata can be distinguished easily at the following loci examined: CK‐D*, LDH‐B*,sMDH‐A* and sMDH‐B*. Among these, CK‐D* and LDH‐B* have fixed allelic differences which can be used as a synoptic key for easy discrimination of the elvers of these two species.
Egg survival and timing of hatch in two Scottish Atlantic salmon stocks
Authors: Donaghy M. J. , Verspoor E.
Published: April 2005

Atlantic salmon eggs from the Rivers Oykel and Shin were monitored in three rivers and in culture. Significant mortality, attributable to low pH, was found for both stocks in the River Oykel though it was eightfold higher for the non‐native Shin eggs. Shin eggs hatched earlier at all three wild sites but hatched later in culture. The observations are consistent with genotype‐environment interactions for pH sensitivity and developmental rate.
Opsin sequences of the rod visual pigments in two species of Poeciliid fish
Authors: Archer S. N. , Hirano J.
Published: April 2005

The rod opsin sequences from Gambusia affinis holbrooki and Poecilia reticulata were cloned and sequenced. The opsin sequences were found to be 96.8% identical, reflecting the similarity of the rod visual pigment absorbances in these two Poeciliid fish.
Nicotine analogues: a review of tobacco industry research interests
Authors: Vagg Rosemary , Chapman Simon
Published: April 2005

Aims  To explore the tobacco industry's interest and intentions driving its nicotine analogue research.

Methods  Review of internal tobacco industry documents regarding nicotine analogues released as part of the Master Settlement Agreement between the tobacco industry and US state governments in 1998.

Findings  The tobacco industry investigated nicotine analogues extensively. Four principal areas of interest are evident. First, research on tobacco products was directed towards greater understanding of nicotine pharmacology, how to screen for potential analogues and how to separate the central and peripheral effects of nicotine. Secondly, interest lay in the potential for analogues to replace nicotine in order to create more ‘desirable’ products and to circumvent anticipated nicotine regulation. Thirdly, interest lay in potential pharmaceutical applications for analogues such as treatments for neurological disorders. Finally, there was interest in the public relations potential of the therapeutic potential of analogues to reduce the demonization of nicotine, by allowing the industry to point to its beneficial uses.

Conclusions  With tobacco product and nicotine regulation being increasingly advocated in tobacco control it is important to understand the industry's interests in the potential role of nicotine analogues. Initial interest included using analogues as a means to circumvent regulation, but evidence suggests these plans were discarded due to fear that this may have instigated regulation of tobacco products. Nicotine analogue research has led to potential therapeutic uses for Alzheimer's and Parkinson's diseases and alarmingly for the industry, to a potential vaccine to prevent nicotine addiction.

Recommendations  Tobacco manufacturers should be obliged to declare all additives being used in tobacco products. Regulatory bodies should be aware that that there is a distinct possibility that the industry has discovered ways to circumvent future regulation of nicotine through the utilization of nicotine analogues. Any regulatory drafting should broaden the definition of nicotine in order to incorporate analogues into the scope of pharmacologically active substances being regulated.
HCV viremia is associated with drug use in young HIV‐1 and HCV coinfected pregnant and non‐pregnant women*
Authors: Nikolopoulou Georgia B. , Nowicki Marek J. , Du Wenbo , Homans James , Stek Alice , Kramer Francoise , Kovacs Andrea
Published: April 2005

Aims  Vertical transmission of HCV is increased among HIV‐1/HCV coinfected women and is related to HCV viral load. In this study we assessed clinical and demographic factors associated with HCV viremia in a cohort of young pregnant and non‐pregnant mothers coinfected with HIV‐1.

Design  A cross‐sectional clinic‐based study nested within a prospective cohort study.

Methods  From 1988 to 2000, HIV‐1 + pregnant and non‐pregnant women with children followed in a large maternal, child and adolescent HIV‐1 clinic were evaluated for HCV infection using EIA 3.0. HCV RNA levels were determined for HCV antibody + women using polymerase chain reaction. Demographic and clinical characteristics between HCV‐RNA(+) and HCV‐RNA(–) women and between pregnant and non‐pregnant HIV‐1/HCV coinfected women were compared using univariate and multivariate analyses.

Findings  Among 359 HIV‐1(+) women, 84 (23%) were HCV‐ab + and 49/84 (58%) had detectable HCV‐RNA in plasma. Median age was 31. CD4 counts, HIV‐1 RNA levels and demographic characteristics were similar for viremic and non‐viremic women and pregnant and non‐pregnant women. However, viremic women were more likely to report a history of (88% versus 43%; P < 0.001) or active injection drug use (AIDU) (83% versus 29%; P < 0.001). Logistic regression analysis showed that HCV viremia was associated significantly with AIDU (adjusted OR: 15.17; 95% CI: 3.56, 64.56) after adjusting for age, race, number of sexual partners, pregnancy status, CD4 counts and HIV‐1 viral load.

Conclusion  In this cohort of young HIV‐1 and HCV coinfected women, HCV viremia was associated strongly with active injection drug use, perhaps due to reinfection or reactivation of HCV. Thus, careful evaluation for HCV infection and counseling related to drug use may be necessary.
Is there really a ‘J‐shaped’ curve in the association between alcohol consumption and symptoms of depression and anxiety? Findings from the Mater‐University Study of Pregnancy and its outcomes*
Authors: Alati Rosa , Lawlor Debbie A. , Najman Jake M. , Williams Gail M. , Bor William , O'Callaghan Michael
Published: April 2005

Aims  To determine the nature of the association between alcohol consumption and symptoms of anxiety and depression in women.

Design  Prospective cohort study of women (n = 4527) who received antenatal care at a major public hospital (Mater Misericordiae Hospital) in South Brisbane between 1981 and 1984 and who have follow‐up data on alcohol use, depressive and anxiety symptoms over a 14‐year period.

Findings  At the 5‐year follow‐up there was a ‘J‐shaped’ association between alcohol consumption and both symptoms of depression and of anxiety. However, at the baseline assessment and the 14‐year follow‐up alcohol consumption was linearly and positively associated with depressive symptoms with increasing prevalence of symptoms with greater consumption. At the 5‐year follow‐up the prevalence of depressive and anxiety symptoms among those who were abstainers at both baseline and 5‐year follow‐up was similar to that among those who had been previous drinkers and then become abstainers (P = 0.67). Similarly, the prevalence of these symptoms was the same at the 14‐year follow‐up comparing those who had been abstainers at baseline, 5‐year and 14‐year follow‐up to those who had previously consumed alcohol but were then abstainers.

Conclusions  The nature of the association between alcohol consumption and symptoms of depression and anxiety may vary across their life course in women. Previous drinkers who become abstainers do not appear to be at any higher risk of symptoms of depression or anxiety compared to those who always abstained, suggesting that increased symptoms in abstainers at age 30 is not due to ‘sick quitters’. The association of high alcohol consumption with symptoms of depression and anxiety may be confounded by low income and smoking.
Marijuana use and car crash injury
Authors: Blows Stephanie , Ivers Rebecca Q. , Connor Jennie , Ameratunga Shanthi , Woodward Mark , Norton Robyn
Published: April 2005

Aims  To investigate the relationship between marijuana use prior to driving, habitual marijuana use and car crash injury

Design and setting  Population based case–control study in Auckland, New Zealand.

Participants  Case vehicles were all cars involved in crashes in which at least one occupant was hospitalized or killed anywhere in the Auckland region, and control vehicles were a random sample of cars driving on Auckland roads. The drivers of 571 case and 588 control vehicles completed a structured interview.

Measurements  Self reported marijuana use in the 3 hours prior to the crash/survey and habitual marijuana use over the previous 12 months were recorded, along with a range of other variables potentially related to crash risk. The main outcome measure was hospitalization or death of a vehicle occupant due to car crash injury.

Findings  Acute marijuana use was significantly associated with car crash injury, after controlling for the confounders age, gender, ethnicity, education level, passenger carriage, driving exposure and time of day (OR 3.9, 95% CI 1.2–12.9). However, after adjustment for these confounders plus other risky driving at the time of the crash (blood alcohol concentration, seat‐belt use, travelling speed and sleepiness score), the effect of acute marijuana intake was no longer significant (OR 0.8, 95% CI 0.2–3.3). There was a strong significant association between habitual use and car crash injury after adjustment for all the above confounders plus acute use prior to driving (OR 9.5, 95% CI 2.8–32.3).

Conclusions  This population‐based case–control study indicates that habitual use of marijuana is strongly associated with car crash injury. The nature of the relationship between marijuana use and risk‐taking is unclear and needs further research. The prevalence of marijuana use in this driving population was low, and acute use was associated with habitual marijuana use, suggesting that intervention strategies may be more effective if they are targeted towards high use groups.
Characteristic sequence changes of hepatitis C virus genotype 2b associated with sustained biochemical response to IFN therapy
Authors: Tanabe Y. , Nagayama K. , Enomoto N. , Izumi N. , Tazawa J. , Kurosaki M. , Sakamoto N. , Sato C. , Watanabe M.
Published: April 2005

Summary.  In hepatitis C virus (HCV) genotype 2b infection, viral eradication (sustained viral response; sVR) is obtained in about 40% by interferon monotherapy, whereas a considerable proportion of non‐sVR patients exhibit sustained biochemical response (sBR) showing normal biochemical values despite persistent viraemia. However, the mechanism of sBR has not yet been established. In this study, we analysed serial changes in full‐length sequences of HCV genotype 2b before and after interferon (IFN) therapy in five patients with sBR and five with no response (NR; persistent viraemia and abnormal biochemical values after IFN therapy). The overall substitution rate of amino acids in the full‐length HCV genome was higher in the sBR group than in the NR group [2.22 ± 0.48 (10−3 changes/site/year) vs 1.04 ± 0.30: P = 0.002]. When the genetic changes were analysed for individual HCV proteins, the sBR group had significantly higher substitution rates of amino acid in NS4A [8.82 ± 2.80 (10−3 changes/site/year) vs 0: P = 0.001]. These amino acid changes in sBR were mainly located in the binding motifs of HLA class I molecules including those frequently found in the Japanese population. These results demonstrated that the greater amino acid changes of HCV arising during interferon therapy are associated with the establishment of sBR. Although functional significance of these changes awaits further investigation, the finding that amino acid changes in NS4A in sBR patients are mainly located in the HLA class I binding motifs illustrated the potential roles of the escape mutations of HCV genome from CTLs in the decreasing activities of hepatitis in sBR.
Immunomodulatory effects of selective leucocytapheresis as a new adjunct to interferon‐α2b plus ribavirin combination therapy: a prospective study in patients with high plasma HCV viraemia
Authors: Sawada K. , Masaki N. , Hayashi S. , Zeniya M. , Ishikawa T. , Takahashi H. , Ohnishi K. , Fukunaga K. , Hara N. , Yamamoto T. , Hada T. , Toda G.
Published: April 2005

Summary.  Efficacy of interferon‐α2b (IFN) + ribavirin (IFN/RBV) combination in patients with high plasma hepatitis C virus (HCV) is very poor. Dysregulated CD4+ /CD8+ T cells is involved in both impaired cell‐mediated immunity and resistance to IFN. Adsorptive granulocytes and monocytes apheresis (GMA) can remove infected leucocytes which are extrahepatic HCV reservoirs and also has been associated with intriguing immunomodulation and increases in CD4+ T cells. Our aim was to see if GMA enhances the efficacy of IFN/RBV. Twenty‐four patients, 13 IFN resistant and 11 IFN naive were enrolled. Seventeen were genotype 1b and 7 were 2a or 2b. Mean plasma HCV‐RNA was 612.9 (100–850) kIU/mL and alanine aminotransferase, 108 (41–373) U/L. GMA was performed with Adacolumn at one session/day for five consecutive days and IFN/RBV was started within 24 h after the last GMA session. Daily 6 million units of IFN, six times/week for 2 weeks and then three times/week for 22 weeks were given with RBV (600–800 mg/day/patient). Patients were followed for 6 months. GMA was associated with a significant increase in lymphocyte counts, complement activation fragment C3a and falls in tissue necrosis factor‐alpha, and IL‐8 produced by peripheral blood leucocytes. At week 24, 20 of 24 patients (83%) were HCV negative and by end of follow‐up (week 49), the remission was sustained in 14 of 24 patients (58%) including 100% of patients with 2a or 2b. In conclusion, enhanced efficacy of IFN/RBV following GMA might be attributed to a more efficient immune function and a renewed IFN signaling towards HCV.
Prevalence and sexual risk of hepatitis C virus infection when human immunodeficiency virus was acquired through sexual intercourse among patients of the Lyon University Hospitals, France, 1992–2002
Authors: D'Oliveira A. , Voirin N. , Allard R. , Peyramond D. , Chidiac C. , Touraine J.‐L. , Fabry J. , Trepo C. , Vanhems P.
Published: April 2005

Summary.  To report the prevalence and the risk factors for hepatitis C virus (HCV) infection in a hospital cohort of 2691 sexually human immunodeficiency virus (HIV)‐infected patients. The patients were enrolled in the Lyon section of the French Hospital Database on HIV between 1992 and 2002. Baseline characteristics were analysed. The detection of HCV‐antibodies (Ab) was used for diagnosis. The HCV‐Ab prevalence rate was 5.7 and 12.89% for individuals infected by HIV after homosexual intercourse or heterosexual intercourse, respectively. HCV‐Ab was three times more frequently found among patients infected with HIV after heterosexual intercourse compared with patients infected with HIV after homosexual intercourse (adjusted OR: 3.2, 95% CI: 2.28–4.62, multiple logistic regression). The risk of HCV infection among HIV‐infected individuals differed according to sexual behaviour. The determinants associated with HCV transmission through the sexual route needs to be explored further.
Mutations in the E2–PePHD region of hepatitis C virus type 1b in patients with hepatocellular carcinoma
Authors: Bagaglio S. , De Mitri M. S. , Lodrini S. , Paties C. , Cassini R. , Bianchi G. , Bernardi M. , Lazzarin A. , Morsica G.
Published: April 2005

Summary.  An interaction between the protein kinase (PKR)–eIF2‐alpha phosphorylation homology domain (PePHD) within the E2 protein of hepatitis C virus (HCV) and cell protein kinase (PKR) may affect the control of protein synthesis and cell growth. In an attempt to investigate the genetic variability of the E2–PePHD domain in hepatocellular carcinoma (HCC), we studied sera and liver tissues from HCC patients. The partial E2–PePHD region was analysed by direct sequencing of the sera of 47 HCCs in cirrhotic livers and 31 cases of chronic active hepatitis (CAH), and tumoral and non‐tumoral liver tissues from 13 HCC patients. A similar number of mutations was detected within the E2 domain in the HCC and CAH cases, but nine of the 47 HCCs (19%) showed an amino acid (aa) mutation at position 660, eight of which involved a change in the same aa (alanine instead of serine; A/S). No such mutation was detected in any of the PePHD sequences from the CAH patients: this difference was statistically significant (P = 0.008). The aa change at position 660 was also found in two sequences from tumoral but not non‐tumoral tissue from the same liver. The analysis of 461 sequences obtained from GenBank supports the conclusion that the observed aa change is an infrequent event in HCV‐infected patients, thus suggesting that it could be associated with HCC.
Detection of multiple hepatitis C virus genotypes in a cohort of injecting drug users
Authors: Bowden S. , McCaw R. , White P. A. , Crofts N. , Aitken C. K.
Published: April 2005

Summary.  Multiple genotypes of the hepatitis C virus (HCV) were detected in five of 138 HCV RNA positive injecting drug users (IDUs) recruited in Melbourne, Australia. Two were detected by combined LiPA and core and NS5a region sequencing, and three more (selected for testing due to their high‐risk behaviour) by heteroduplex mobility analysis. We conclude that the true prevalence of mixed infection in IDUs is undoubtedly higher than the 3.6% (five of 138) we observed, and is underestimated by LiPA, the most common method of genotyping. As responsiveness to HCV treatment varies significantly with genotype, a high prevalence of mixed HCV infections in IDUs must diminish overall treatment efficacy and lessen our ability to reduce the burden of HCV‐related disease.
Treatment of hepatitis C
Authors: Heathcote J. , Main J.
Published: April 2005

Summary. The combination of pegylated interferon alpha and ribavirin has improved treatment success rates in patients with hepatitis C with sustained response rates of just over 50% overall and more than 70% for those with genotypes 2 and 3. This article reviews the use of combination therapy, contraindications, factors influencing response and describes approaches to specific patient groups.
Activation of both acfA and acfD transcription by Vibrio cholerae ToxT requires binding to two centrally located DNA sites in an inverted repeat conformation
Authors: Withey Jeffrey H. , DiRita Victor J.
Published: April 2005

The Gram‐negative bacterium Vibrio cholerae is the infectious agent responsible for the disease Asiatic cholera. The genes required for V. cholerae virulence, such as those encoding the cholera toxin (CT) and toxin‐coregulated pilus (TCP), are controlled by a cascade of transcriptional activators. Ultimately, the direct transcriptional activator of the majority of V. cholerae virulence genes is the AraC/XylS family member ToxT protein, the expression of which is activated by the ToxR and TcpP proteins. Previous studies have identified the DNA sites to which ToxT binds upstream of the ctx operon, encoding CT, and the tcpA operon, encoding, among other products, the major subunit of the TCP. These known ToxT binding sites are seemingly dissimilar in sequence other than being A/T rich. Further results suggested that ctx and tcpA each has a pair of ToxT binding sites arranged in a direct repeat orientation upstream of the core promoter elements. In this work, using both transcriptional lacZ fusions and in vitro copper‐phenanthroline footprinting experiments, we have identified the ToxT binding sites between the divergently transcribed acfA and acfD genes, which encode components  of the accessory colonization factor required for efficient intestinal colonization by V. cholerae. Our results indicate that ToxT binds to a pair of DNA sites between acfA and acfD in an inverted repeat orientation. Moreover, a mutational analysis of the ToxT binding sites indicates that both binding sites are required by ToxT for transcriptional activation of both acfA and acfD. Using copper‐phenanthroline footprinting to assess the occupancy of ToxT on DNA having mutations in one of these binding sites, we found that protection by ToxT of the unaltered binding site was not affected, whereas protection by ToxT of the mutant binding site was significantly reduced in the region of the mutations. The results of further footprinting experiments using DNA templates having +5 bp and +10 bp insertions between the two ToxT binding sites indicate that both binding sites are occupied by ToxT regardless of their positions relative to each other. Based on these results, we propose that ToxT binds independently to two DNA sites between acfA and acfD to activate transcription of both genes.
The PilC adhesin of the Neisseria type IV pilus – binding specificities and new insights into the nature of the host cell receptor
Authors: Kirchner Marieluise , Meyer Thomas F.
Published: April 2005

Type IV pili of Neisseria gonorrhoeae and Neisseria meningitidis mediate the first contact to human mucosal epithelial cells, an interaction which is also critical for the interaction with vascular endothelial cells. The PilC proteins have been characterized as the principal pilus‐associated adhesin. Here we show that PilC2 exhibits a defined cell and tissue tropism, as it binds to human epithelial and endothelial cell lines, but not to human T cells or fibroblasts. Piliated gonococci and PilC2 exhibit similar patterns of binding to human epithelial and endothelial cells, supporting the function of PilC as the key pilus adhesin. Although CD46 has previously been suggested to be a pilus receptor, several observations indicate that neisserial type IV pili and the pilus adhesin PilC2 interact with epithelial cells in a CD46 independent manner. Biochemical approaches were used to characterize the nature of host cell factors mediating binding of piliated gonococci and PilC2 protein. Our data indicate that the putative host cell receptor for gonococcal pili and the PilC2 pilus adhesin is a surface protein. Glycostructures were found to not be involved in binding. Moreover, we observed the uptake of purified PilC2 protein together with its receptor via receptor‐mediated endocytosis and subsequent receptor re‐exposure on the cell surface. Our data support the existence of a specific pilus receptor and provide intriguing information on the nature of the receptor.
Iron limitation induces SpoT‐dependent accumulation of ppGpp in Escherichia coli
Authors: Vinella Daniel , Albrecht Christian , Cashel Michael , D’Ari Richard
Published: April 2005

In Escherichia coli the β‐lactam mecillinam specifically inhibits penicillin‐binding protein 2 (PBP2), a peptidoglycan transpeptidase essential for maintaining rod shape. We have previously shown that PBP2 inactivation  results  in  a  cell  division  block  and  that an increased concentration of the nucleotide ppGpp, effector of the RelA‐dependent stringent response, confers mecillinam resistance and allows cells to divide as spheres in the absence of PBP2 activity. In this study we have characterized an insertion mutation which confers mecillinam resistance in wild‐type and ΔrelA strains but not in ΔrelAΔspoT strains, devoid of ppGpp. The mutant has an insertion in the fes gene, coding for enterochelin esterase. This cytoplasmic enzyme hydrolyses enterochelin–Fe3+ complexes, making the scavenged iron available to the cells. We show that inactivation of the fes gene causes iron limitation on rich medium plates and a parallel SpoT‐dependent increase of the ppGpp pool, as judged by the induction of the iron‐regulated fiu::lacZ fusion and the repression of the stringently controlled P1rrnB::lacZ fusion respectively. We further show, by direct ppGpp assays, that iron starvation in liquid medium produces a SpoT‐dependent increase of the ppGpp pool, strongly suggesting a role for iron in the balance of the two activities of SpoT, synthesis and hydrolysis of (p)ppGpp. Finally, we present evidence that ppGpp exerts direct or indirect positive control on iron uptake, suggesting a simple homeostatic regulatory circuit: iron limitation leads to an increased ppGpp pool, which increases the expression of iron uptake genes, thereby alleviating the limitation.
A role for the Plasmodium falciparum RESA protein in resistance against heat shock demonstrated using gene disruption
Authors: Silva Monica Diez , Cooke Brian M. , Guillotte Micheline , Buckingham Donna W. , Sauzet Jean‐Pierre , Scanf Cecile Le , Contamin Hugues , David Peter , Mercereau‐Puijalon Odile , Bonnefoy Serge
Published: April 2005

During erythrocyte invasion, the Plasmodium falciparum Ring‐infected erythrocyte surface antigen (RESA) establishes specific interactions with spectrin. Based on analysis of strains with a large chromosome 1 deletion, RESA has been assigned several functions, none of which is firmly established. Analysis of parasites with a disrupted resa1 gene and isogenic parental or resa3‐disrupted controls confirmed the critical role of RESA in the surface reactivity of immune adult sera on glutaraldehyde‐fixed ring stages. Absence of RESA did not influence merozoite invasion or erythrocyte membrane rigidity, was associated with a modest increase of cytoadhesion to CD36 under conditions of flow, but resulted in marked susceptibility to heat shock. resa1‐KO‐infected erythrocytes were prone to heat‐induced vesiculation like uninfected erythrocytes, whereas parental or resa3‐KO infected erythrocytes remained undamaged. Furthermore, a 6 h exposure of ring stages at 41°C resulted in 33% culture inhibition of resa1‐KO parasites while marginally impacting parental and resa3‐KO parasite growth. This points to a role for RESA in protecting the infected erythrocyte cytoskeleton during febrile episodes. Infection patterns of resa1‐KO and parental parasites in Saimiri sciureus indicated that RESA does not, at least on its own, modulate virulence in the squirrel monkey, as had been previously suggested.