bluuebunny/crossref_metadata_2025_split huggingface dataset:
Initial Permeability Processes in Nickel-Cobalt Ferrites of Various Densities
Authors: Pippin J. E. , Thiess G. H. 
Published: March 2008

Initial permeability has been measured at a frequency of 10 Mc/sec on ferrites of composition Ni1−αCoαMn0.02Fe1.9O4± with varying densities. Here α = 0, 0.005, 0.01, 0.015, 0.02, 0.025, 0.03, 0.04, and  0.06, and density is varied for each composition between 3.8 g/cm3 and 5.1 g/cm3.
The data are presented in a family of curves of permeability, μ′, versus density with α as a parameter, and in a family of curves of μ′ versus α with density as a parameter. For α = 0, the extremely rapid increase of μ′ at high density is indicative of an increase in wall motion, the increase being much too sharp to explain by a rotational model. For α≥0.04, this rapid increase is not seen, suggesting that the walls are almost completely pinned at these cobalt contents.
For high densities, the curve of μ′ versus α shows a sharp decrease with the first cobalt addition, then rises to a maximum near α = 0.03, and decreases for further cobalt additions. But ferromagnetic resonance line width measurements show that the crystalline anisotropy is decreased by the first cobalt addition, reaches a minimum near α = 0.03, and subsequently increases again. Thus it is concluded that rotational contributions to μ′ must have been increased by the first cobalt addition; therefore some other mechanism of magnetization, presumably domain wall motion, existed in the beginning, and its contribution to μ′ was decreased by more than the rotational contribution was increased.
Internal Structure of Cross-Tie Walls in Thin Permalloy Films through High-Resolution Bitter Techniques
Authors: Moon Ralph M. 
Published: March 2008

The use of a water immersion objective with the optical microscope for Bitter pattern studies has resulted in a significant improvement in resolution. A discussion of technique in using such an objective is presented.
Applied to the study of cross-tie domain walls in thin Permalloy films, this technique has revealed details of internal wall structure. In the proposed model for such walls the magnetization within the wall is thought to be predominantly in the plane of the film, with periodic transition regions in which the magnetization is normal to the film. This configuration reduces the large magnetostatic energy which would be associated with a conventional 180° wall. Areas of low particle density are observed at the intersection of the main wall and cross-ties and in the main wall midway between cross-ties. From conventional ideas of colloid-pattern formation, these areas might be expected to have a high particle density because they are the transition regions in which the magnetization is normal to the film. The apparent conflict is resolved by assuming that these regions are large compared to the colloid particle size so that the fringing field at the edge of the region governs the particle distribution. In support of the model, convincing evidence is presented of the reported shift of colloid particles when an external field is applied normal to the film.
Crystal methamphetamine smoking among regular ecstasy users in Australia: increases in use and associations with harm
Authors: KINNER STUART A. , DEGENHARDT LOUISA 
Published: March 2008

AbstractIntroduction. This study examined (a) changes in crystal methamphetamine use among regular ecstasy users (REU) in Australia and (b) associations of crystal use and smoking with demographics, drug use and harm. Design and Methods. Cross‐sectional surveys (2000–06) of REU in three Australian capital cities, and in 2006, 750 REU in all Australian capital cities. The interview included: demographics, drug use, risk behaviour, recent criminal activity and methamphetamine dependence using Severity of Dependence Scale. Results. There was little change in overall methamphetamine use, but a marked increase in crystal methamphetamine smoking. Among recent methamphetamine users in 2006 (n = 606), crystal methamphetamine users (n = 364) reported more frequent methamphetamine use and higher levels of dependence. Compared with those who had used only other forms of methamphetamine, recent crystal methamphetamine users were more likely to ‘binge’ on drugs for 48 hours, engage in crime and experience financial and legal problems related to drug use. Non‐smoking crystal methamphetamine users (n = 78) more often reported recent injecting and heroin use. Recent smokers were more likely to have: greater polydrug use, recently overdosed on a ‘party drug’, and accessed medical services for their drug use. Many of these associations were accounted for by their injecting and heavier methamphetamine use, rather than smoking per se. Conclusions. Crystal methamphetamine smoking among REU has increased markedly and is associated with significant harm. This appears related to smokers' heavier levels of methamphetamine use. Effective harm reduction strategies should be tailored to these specific risks.
A systematic review of cognitive and behavioural therapies for methamphetamine dependence
Authors: LEE NICOLE K. , RAWSON RICHARD A. 
Published: March 2008

AbstractIntroduction and Aims. The use of methamphetamine is widespread and poses significant challenges for treatment providers. Much of the treatment knowledge about this group has been extrapolated from studies of treatment for cocaine dependence. Medications have been shown to be of limited effectiveness for methamphetamine users, making psychological interventions the treatment of choice. Approach. This paper describes a systematic review of cognitive–behavioural and behavioural interventions for methamphetamine users. A systematic search of published literature was undertaken focusing only on randomised trials. Key Findings. There were a relatively small number of intervention studies that compared cognitive–behavioural or behavioural interventions using randomised trial methodology. Most commonly, studies examined cognitive–behaviour therapy (CBT) and/or contingency management (CM). Treatment with CBT appears to be associated with reductions in methamphetamine use and other positive changes, even over very short periods of treatment (two and four sessions). CM studies found a significant reduction of methamphetamine during application of the procedure, but it is not clear if these gains are sustained at post‐treatment follow‐up. Implications. The review highlights that there are effective treatments for methamphetamine dependence. Alcohol and other drug (AOD) clinicians are familiar with these types of interventions and should use them and convey to clients that they are effective. Services and policy makers should ensure that best practice interventions are implemented within AOD services. Conclusion. Psychological intervention is effective in addressing methamphetamine use and dependence. CBT and contingency management are two accessible interventions that are implemented easily within current AOD services. There is still more work to conduct in improving methamphetamine treatment, however, and further research into cognitive–behavioural and behavioural treatments for methamphetamine users is required, with a focus on improving longevity of the effect of intervention and improving effectiveness among more complex presentations.
The principles of agonist pharmacotherapy for psychostimulant dependence
Authors: SHEARER JAMES 
Published: March 2008

AbstractIssues. Psychostimulant dependence is a chronic, relapsing condition which is highly treatment refractory. No medications to date have been any more successful than placebo in reducing psychostimulant use in dependent patients. Agonist strategies have attracted limited attention. Approach. Successful examples of agonist pharmacotherapy in the treatment of heroin and nicotine dependence are first considered. Agonist pharmacological approaches to the treatment of psychostimulant dependence are then examined, based on the dopamine receptor agonist and indirect dopamine agonist strategies. Finally, the potential extension of the concept of agonist pharmacotherapy to include the novel non‐amphetamine‐type stimulant, modafinil, is discussed. Conclusions. Agonist approaches appear to be viable with risks outweighed by benefits in carefully selected, monitored and motivated patients. On the other hand, the effectiveness of indirect agonists such as dexamphetamine and methylphenidate are not established. Further research is required to determine optimal treatment models (whether maintenance or withdrawal), effective safe dosages and duration (short or long term).
Quite a lot of smoke but very limited fire—the use of methamphetamine in Europe
Authors: GRIFFITHS PAUL , MRAVCIK VIKTOR , LOPEZ DOMINIQUE , KLEMPOVA DANICA 
Published: March 2008

AbstractIntroduction and Aims. This paper provides an overview of the historical development, current situation and potential future diffusion of methamphetamine (MA) use in Europe. Design and Methods. The analysis is based on a review of published and grey literature, as well as data collected as part of the ongoing monitoring of the drug situation in Europe. Some qualitative surveys among high‐risk populations do exist, but overall the general low prevalence of methamphetamine use in most of Europe means that the data available to explore patterns of use are limited. Results. In many parts of Europe, amphetamine use is well established and the injecting of amphetamines has historically constituted an important component of the drug problem in many Nordic countries. Methamphetamine problems are long documented in the Czech and Slovak republics, but there is no current evidence of widespread use of MA elsewhere in Europe. Concern that MA use is spreading in Europe is prompted by some reports of use among high‐risk groups. However, the evidence available suggests that even in high‐risk populations, the use of MA currently remains uncommon. Europe accounted for less than 1% of worldwide MA seizures in 2005, and over the period 2004–05 European ephedrine seizures amounted for 6% of the global figure. Discussion. The spread of MA use is limited and no strong evidence exists that significant diffusion is occurring. It appears likely that methamphetamine diffusion in Europe is impeded by a strong market for other stimulant drugs [cocaine, amphetamine and methylenedioxymethamphetamine (MDMA)]. The future potential for the diffusion of MA may be influenced by factors such as: the relative availability and popularity of other drugs; possible ‘leakage’ from areas of historical high prevalence; travel by young Europeans to areas of high prevalence; and how users perceive MA as a desirable, suitable and cost‐effective alternative to other stimulants available on the European illicit drug market.
A qualitative study of sexual behaviours among methamphetamine users in Chiang Mai, Thailand: a typology of risk
Authors: SHERMAN SUSAN G. , GANN DONALD , GERMAN DANIELLE , SIRIROJN BANGORN , THOMPSON NICHOLAS , ARAMRATTANA APINUN , CELENTANO DAVID 
Published: March 2008

AbstractIntroduction and Aims. Methamphetamine (MA) has become the leading drug of abuse in northern Thailand over the past several years, particularly among youth. The current qualitative study explores the relationship between sexual behaviours and MA. Design and Methods. Between March 2002 and January 2003, 48 in‐depth interviews with young MA users aged 15–2 years in Chiang Mai. Interviews were transcribed verbatim in Thai and translated into English. Data were analysed inductively using the constant comparative method common to grounded theory methods. Atlas‐ti was used for data management. The current analysis was stratified by gender. Results. Participants were 44% male and the median age was 20 years. At the time of the interviews, 70% were not using MA. A typology of experiences with and feelings about MA's relationship to sexual activity emerged: (1) enhanced libido—individuals who found that MA enhances their sexual experiences (n = 13); (2) decreased libido or no effect—individuals who found that MA detracted from sexual desire (n = 22); and (3) virgins (n = 13). Discussion and Conclusions. Participants reported several distinct patterns of relationship between MA and sex. Tailored interventions are needed that address specific patterns of sexual behaviors among youth in order to promote sustainable safer sex behaviours in this population.
Exclusion of a Proton ATPase from the Apical Membrane Is Associated with Cell Polarity and Tip Growth inNicotiana tabacumPollen Tubes
Authors: Certal Ana C. , Almeida Ricardo B. , Carvalho Lara M. , Wong Eric , Moreno Nuno , Michard Erwan , Carneiro Jorge , Rodriguéz-Léon Joaquín , Wu Hen-Ming , Cheung Alice Y. , Feijó José A. 
Published: March 2008

AbstractPolarized growth in pollen tubes results from exocytosis at the tip and is associated with conspicuous polarization of Ca2+, H+, K+, and Cl− -fluxes. Here, we show that cell polarity in Nicotiana tabacum pollen is associated with the exclusion of a novel pollen-specific H+-ATPase, Nt AHA, from the growing apex. Nt AHA colocalizes with extracellular H+ effluxes, which revert to influxes where Nt AHA is absent. Fluorescence recovery after photobleaching analysis showed that Nt AHA moves toward the apex of growing pollen tubes, suggesting that the major mechanism of insertion is not through apical exocytosis. Nt AHA mRNA is also excluded from the tip, suggesting a mechanism of polarization acting at the level of translation. Localized applications of the cation ionophore gramicidin A had no effect where Nt AHA was present but acidified the cytosol and induced reorientation of the pollen tube where Nt AHA was absent. Transgenic pollen overexpressing Nt AHA-GFP developed abnormal callose plugs accompanied by abnormal H+ flux profiles. Furthermore, there is no net flux of H+ in defined patches of membrane where callose plugs are to be formed. Taken together, our results suggest that proton dynamics may underlie basic mechanisms of polarity and spatial regulation in growing pollen tubes.
Heme, a Plastid-Derived Regulator of Nuclear Gene Expression inChlamydomonas
Authors: von Gromoff Erika D. , Alawady Ali , Meinecke Linda , Grimm Bernhard , Beck Christoph F. 
Published: March 2008

AbstractTo gain insight into the chloroplast-to-nucleus signaling role of tetrapyrroles, Chlamydomonas reinhardtii mutants in the Mg-chelatase that catalyzes the insertion of magnesium into protoporphyrin IX were isolated and characterized. The four mutants lack chlorophyll and show reduced levels of Mg-tetrapyrroles but increased levels of soluble heme. In the mutants, light induction of HSP70A was preserved, although Mg-protoporphyrin IX has been implicated in this induction. In wild-type cells, a shift from dark to light resulted in a transient reduction in heme levels, while the levels of Mg-protoporphyrin IX, its methyl ester, and protoporphyrin IX increased. Hemin feeding to cultures in the dark activated HSP70A. This induction was mediated by the same plastid response element (PRE) in the HSP70A promoter that has been shown to mediate induction by Mg-protoporphyrin IX and light. Other nuclear genes that harbor a PRE in their promoters also were inducible by hemin feeding. Extended incubation with hemin abrogated the competence to induce HSP70A by light or Mg-protoporphyrin IX, indicating that these signals converge on the same pathway. We propose that Mg-protoporphyrin IX and heme may serve as plastid signals that regulate the expression of nuclear genes.
Haplo-Insufficiency ofMPK3inMPK6Mutant Background Uncovers a Novel Function of These Two MAPKs inArabidopsisOvule Development
Authors: Wang Huachun , Liu Yidong , Bruffett Kristin , Lee Justin , Hause Gerd , Walker John C. , Zhang Shuqun 
Published: March 2008

AbstractThe plant life cycle includes diploid sporophytic and haploid gametophytic generations. Female gametophytes (embryo sacs) in higher plants are embedded in specialized sporophytic structures (ovules). Here, we report that two closely related mitogen-activated protein kinases in Arabidopsis thaliana, MPK3 and MPK6, share a novel function in ovule development: in the MPK6 mutant background, MPK3 is haplo-insufficient, giving female sterility when heterozygous. By contrast, in the MPK3 mutant background, MPK6 does not show haplo-insufficiency. Using wounding treatment, we discovered gene dosage–dependent activation of MPK3 and MPK6. In addition, MPK6 activation is enhanced when MPK3 is null, which may help explain why mpk3−/− mpk6+/− plants are fertile. Genetic analysis revealed that the female sterility of mpk3+/− mpk6−/− plants is a sporophytic effect. In mpk3+/− mpk6−/− mutant plants, megasporogenesis and megagametogenesis are normal and the female gametophyte identity is correctly established. Further analysis demonstrates that the mpk3+/− mpk6−/− ovules have abnormal integument development with arrested cell divisions at later stages. The mutant integuments fail to accommodate the developing embryo sac, resulting in the embryo sacs being physically restricted and female reproductive failure. Our results highlight an essential function of MPK3 and MPK6 in promoting cell division in the integument specifically during ovule development.
A Generalized Caprine‐like Hypoplasia Syndrome is localized within a 6‐cM interval on bovine chromosome 13 in the Montbéliarde breed
Authors: Duchesne A. , Manciaux L. , Gautier M. , Floriot S. , Grohs C. , Fritz S. , Druet T. , Schelcher F. , Ducos A. , Eggen A. 
Published: March 2008

SummaryCaprine‐like Generalized Hypoplasia Syndrome (or SHGC) is a new hereditary disorder described in the Montbéliarde breed. We report here the characterization of this new disease, based on the visual examination of animals affected by SHGC, and on physiological and biochemical studies undertaken on samples of both SHGC and normal animals. Biological samples for more than 150 affected calves and their parents have been collected over the past 4 years within the framework of the Bovine Genetic Disease Observatory. First, pedigree analyses showed that the mode of inheritance is most probably autosomal recessive. Then, a genome scan with 113 animals and 140 microsatellite markers revealed a single locus within a 35‐cM region on bovine chromosome 13. Genotypes of 261 animals for 18 new microsatellite markers from the region confirmed the localization of the disorder to a 6‐cM interval. Finally, based on the analysis of haplotypes in 463 Montbéliarde sires, we estimated the frequency of the SHGC mutated allele in the population and could propose a strategy for the systematic eradication of this disorder in the near future.
Microsatellite‐based parentage analysis reveals non‐ideal free distribution in a parasitoid population
Authors: TENTELIER CÉDRIC , GUILLEMAUD THOMAS , FERRY SARAH , FAUVERGUE XAVIER 
Published: March 2008

AbstractHabitat selection by dispersers is the focus of much theoretical models, most of which are based on the assumption of negative density dependence. The archetype of these models is the ideal free distribution, characterized by an evolutionary stable state where more competitors aggregate in better habitats, so that the fitness benefit of resource abundance is equally offset by the cost of competition in all habitats. In this study, we used parentage analysis on microsatellite genotypes to test the ideal free distribution in a natural population of aphid parasitoids. Parentage analysis was conducted on parasitoids emerging from aphid colonies. We inferred the number of foundress females which had reproduced in each colony, as well as the number of offspring for each foundress. As predicted by the ideal free distribution, the number of offspring per foundress per colony did not depend on the number of hosts per colony. However, contrary to ideal free distribution predictions, it was affected by the number of foundresses per colony. In surprising contrast with the basic assumption of negative density dependence, individual fitness increased with the number of foundresses. Moreover, parentage analysis revealed a very low number of offspring per foundress per colony (mean = 1.8). This observed distribution questions the validity of classical models of habitat choice based on competition. Indeed, our results provide a new illustration reinforcing a growing body of theory and data on positive density dependence. Our results also suggest that the avoidance of hyperparasitism and predation, although generally neglected, may shape the distribution of parasitoids in the field.
Drifting grating stimulation reveals particular activation properties of visual neurons in the caudate nucleus
Authors: Nagy Attila , Paróczy Zsuzsanna , Márkus Zita , Berényi Antal , Wypych Marek , Waleszczyk Wioletta J. , Benedek György 
Published: March 2008

AbstractThe role of the caudate nucleus (CN) in motor control has been widely studied. Less attention has been paid to the dynamics of visual feedback in motor actions, which is a relevant function of the basal ganglia during the control of eye and body movements. We therefore set out to analyse the visual information processing of neurons in the feline CN. Extracellular single‐unit recordings were performed in the CN, where the neuronal responses to drifting gratings of various spatial and temporal frequencies were recorded. The responses of the CN neurons were modulated by the temporal frequency of the grating. The CN units responded optimally to gratings of low spatial frequencies and exhibited low spatial resolution and fine spatial frequency tuning. By contrast, the CN neurons preferred high temporal frequencies, and exhibited high temporal resolution and fine temporal frequency tuning. The spatial and temporal visual properties of the CN neurons enable them to act as spatiotemporal filters. These properties are similar to those observed in certain feline extrageniculate visual structures, i.e. in the superior colliculus, the suprageniculate nucleus and the anterior ectosylvian cortex, but differ strongly from those of the primary visual cortex and the lateral geniculate nucleus. Accordingly, our results suggest a functional relationship of the CN to the extrageniculate tecto‐thalamo‐cortical system. This system of the mammalian brain may be involved in motion detection, especially in velocity analysis of moving objects, facilitating the detection of changes during the animal's movement.
Frontal cognitive dysfunction in juvenile myoclonic epilepsy
Authors: Piazzini Ada , Turner Katherine , Vignoli Aglaia , Canger Raffaele , Canevini Maria Paola 
Published: March 2008

Summary
Purpose: The aim of the present study was to investigate the possible frontal cognitive dysfunction in patients with juvenile myoclonic epilepsy (JME) and to compare the results with those of patients with frontal lobe epilepsy (FLE) and temporal lobe epilepsy (TLE), as well as with controls.
Methods: A total of 50 patients with JME, 40 patients with FLE, 40 patients with TLE, and 40 normal controls, all matched for age, education, and IQ, were administered tests to assess frontal functions (the Word Fluency Test and the Wisconsin Card Sorting Test [WCST]). All participants had a normal intelligence level based on the Wechsler Adult Intelligence Scale, and did not take medications other than antiepileptics (AEDs) or have a psychiatric history.
Results: Patients with JME had severe impairment in all administered tasks, similar to that of patients with FLE; TLE patients and controls followed in order. Multiple regression analysis did not disclose any significant effect of clinical variables on the cognitive deficits.
Discussion: These results clearly suggest that JME patients can show some frontal dysfunction, which may affect both epileptogenic features and cognitive processes. Further studies are needed to confirm these findings.