bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of post fit and post length on fracture resistance
Authors: Büttel L. , Krastl G. , Lorch H. , Naumann M. , Zitzmann N. U. , Weiger R.
Published: December 2008

Aim  To investigate (i) the impact of post fit (form‐congruence) and (ii) the influence of post length on the fracture resistance of severely damaged root filled extracted teeth.

Methodology  Ninety‐six single‐rooted human teeth were root filled and divided into four groups (n = 24 per group). Post spaces were prepared with a depth of 6 mm (group 1, 3) and 3 mm (group 2, 4). Form‐congruence with a maximal fit of the post within the root canal space was obtained in groups 1 and 2, whereas there was no form‐congruence in groups 3 and 4. In all groups, glass fibre reinforced composite (FRC) posts were adhesively cemented and direct composite crown build‐ups were fabricated without a ferrule. After thermo‐mechanical loading (1200000×, 5–50 °C), static load was applied until failure. Loads‐to‐failure [in N] were compared amongst the groups.

Results  Post fit did not have a significant influence on fracture resistance, irrespective of the post length. Both groups with post insertion depths of 6 mm resulted in significantly higher mean failure loads (group 1, 394 N; group 3, 408 N) than the groups with post space preparation of 3 mm (group 2, 275 N; group 4, 237 N).

Conclusions  Within the limitations of this study, the fracture resistance of teeth restored with FRC posts and direct resin composite crowns without ferrules was not influenced by post fit within the root canal. These results imply that excessive post space preparation aimed at producing an optimal circumferential post fit is not required to improve fracture resistance of roots.
Restorative justice: two examples from New Zealand schools
Authors: Wearmouth Janice , McKinney Rawiri , Glynn Ted
Published: December 2008

In this article, Janice Wearmouth, formerly professor of education at the University of Wellington, New Zealand and now at Liverpool Hope University, Rawiri McKinney, an advocate for Rangatahi who has recently completed his Master of Education degree, and Ted Glynn, foundation professor of teacher education at the University of Waikato, discuss two examples of restorative justice in practice to illustrate how community norms and values can help to encourage more socially appropriate behaviour. Both examples come from a New Zealand Maori context and interventions undertaken with young men whose behaviour was of concern in school and in the local neighbourhood. The interventions operated through traditional Maori protocols to shift the focus away from individuals on to the whole community in order to focus on‘putting things right’between all those involved in the wrong‐doing. These examples show how the use of traditional community conflict resolution processes was able to resolve tensions, make justice visible and re‐establish harmonious relations between the individuals, the school and between members of the community. The use of restorative practices in schools is not straightforward, however. The authors of this article argue that it requires that schools do not own or completely control the process but are responsive to the local context and recognise the important sources of support that may be found in some of the families and local voluntary community groups within it for addressing problematic student behaviour.
Enabling pupil participation in a study of perceptions of disengagement: methodological matters
Authors: Ravet Jackie
Published: December 2008

Guidance and legislation in the UK suggest that it is becoming increasingly important to listen to the voices of pupils, to acknowledge their rights and to consult and collaborate with them in the development of personalised approaches to their education. In this article, Jackie Ravet, lecturer in inclusive practice at the University of Aberdeen, explores the methodological issues raised by a study of pupil perceptions of their disengagement in the primary classroom. She examines how an interpretative methodology was adapted to enable a group of eight‐ and nine‐year‐old primary school pupils to reflect upon their responses to learning and to express their interpretations, explanations and evaluations of their disengagement. Jackie Ravet's article details the array of interpretative methods used throughout her study with a particular focus upon a sequence of practical, activity‐based interview formats designed to enable pupil communication and participation. This exposition is followed by a critique of the methodology and a discussion of its implications for research involving young children. The article closes with a call for pupils to be more effectively involved in reflecting upon the processes of participative research and in meaningful partnerships for school improvement. This article will be of interest to anyone seeking to enhance consultation and collaboration with pupils.
Effects of MAOA‐Genotype, Alcohol Consumption, and Aging on Violent Behavior
Authors: Tikkanen Roope , Sjöberg Rickard L. , Ducci Francesca , Goldman David , Holi Matti , Tiihonen Jari , Virkkunen Matti
Published: December 2008

Background:  Environmental factors appear to interact with a functional polymorphism (MAOA‐LPR) in the promoter region of the monoamine oxidase A gene (MAOA) in determining some forms of antisocial behavior. However, how MAOA‐LPR modulates the effects of other factors such as alcohol consumption related to antisocial behavior is not completely understood.

Methods:  This study examines the conjunct effect of MAOA‐LPR, alcohol consumption, and aging on the risk for violent behavior. Recidivism in severe impulsive violent behavior was assessed after 7 to 15 years in a sample of 174 Finnish alcoholic offenders, the majority of whom exhibited antisocial or borderline personality disorder or both, and featured impulsive temperament traits.

Results:  The risk for committing new acts of violence increased by 2.3% for each kilogram of increase in yearly mean alcohol consumption (p = 0.004) and decreased by 7.3% for every year among offenders carrying the high activity MAOA genotype. In contrast, alcohol consumption and aging failed to affect violent behavior in the low activity MAOA genotyped offenders. MAOA‐LPR showed no main effect on the risk for recidivistic violence.

Conclusions:  Violent offenders carrying the high activity MAOA genotype differ in several ways from carriers with the low activity MAOA risk allele previously associated with antisocial behavior. Finnish high activity MAOA genotyped risk alcoholics exhibiting antisocial behavior, high alcohol consumption, and abnormal alcohol‐related impulsive and uncontrolled violence might represent an etiologically distinct alcohol dependence subtype.
Combined Scopolamine and Ethanol Treatment Results in a Locomotor Stimulant Response Suggestive of Synergism That is Not Blocked by Dopamine Receptor Antagonists
Authors: Scibelli Angela C. , Phillips Tamara J.
Published: December 2008

Background: Muscarinic acetylcholine receptors (mAChRs) are well positioned to mediate ethanol’s stimulant effects. To investigate this possibility, we examined the effects of scopolamine, a receptor subtype nonselective mAChR antagonist, on ethanol‐induced stimulation in genotypes highly sensitive to this effect of ethanol. We also investigated whether the dopamine D1‐like receptor antagonist, SCH‐23390 or the dopamine D2‐like receptor antagonist, haloperidol, could block the extreme stimulant response found following co‐administration of scopolamine and ethanol.

Methods: Scopolamine (0, 0.0625, 0.125, 0.25, or 0.5 mg/kg) was given 10 minutes prior to saline or ethanol (0.75 to 2 g/kg) to female FAST (Experiment I) or DBA/2J (Experiment II) mice that were then tested for locomotion for 30 minutes. In Experiments III and IV, respectively, SCH‐23390 (0, 0.015, or 0.03 mg/kg) was given 10 minutes prior, and haloperidol (0, 0.08, or 0.16 mg/kg) was given 2 minutes prior, to scopolamine (0 or 0.5 mg/kg), followed 10 minutes later by saline or ethanol (1.5 g/kg) and female DBA/2J mice were tested for locomotion for 30 minutes.

Results: FAST and DBA/2J mice displayed a robust enhancement of the locomotor effects of ethanol following pretreatment with scopolamine that was suggestive of synergism. SCH‐23390 had no effect on the response to the scopolamine + ethanol drug combination, nor did it attenuate ethanol‐ or scopolamine‐induced locomotor activity. Haloperidol, while attenuating the effects of ethanol, was not able to block the effects of scopolamine or the robust response to the scopolamine‐ethanol drug combination.

Conclusions: These results suggest that while muscarinic receptor antagonism robustly enhances acute locomotor stimulation to ethanol, dopamine receptors are not involved in the super‐additive interaction of scopolamine and ethanol treatment. They also suggest that in addition to cautions regarding the use of alcohol when scopolamine is clinically prescribed due to enhanced sedative effects, enhanced stimulation may also be a concern.
Sensitization, Duration, and Pharmacological Blockade of Anxiety‐Like Behavior Following Repeated Ethanol Withdrawal in Adolescent and Adult Rats
Authors: Wills Tiffany A. , Knapp Darin J. , Overstreet David H. , Breese George R.
Published: December 2008

Background: Repeated ethanol withdrawal sensitizes anxiety‐like behavior in adult rats and causes anxiety‐like behavior and decreased seizure thresholds in adolescent rats. Current experiments determined if adolescent rats exhibit sensitized anxiety‐like behavior, the duration of this effect, if drug pretreatments blocked these effects, and if these effects differed from those seen in adults.

Methods: Male adolescent rats received three 5‐day cycles of 2.5% ethanol diet (ED) separated by two 2‐day withdrawal periods, continuous 15 days of 2.5%ED, or a single 5‐day cycle of 2.5%ED. Male adult rats received three 5‐day cycles of either 2.5% or 3.5%ED. These groups were tested 5 hours into the final withdrawal for social interaction (SI) deficits (an index of anxiety‐like behavior). Ethanol intake was monitored throughout and blood concentrations were obtained from separate groups of rats. Additionally, adolescent rats were tested for SI 1, 2, 7, 14, and 18 days and adults 1 and 2 days after the final withdrawal. Some adolescent rats were also pretreated with the CRF1antagonist CP‐154,526, the 5‐HT1Aagonist buspirone, or the benzodiazepine receptor antagonist flumazenil during the first 2 withdrawals.

Results: SI was reduced in adolescent rats following repeated withdrawals of 2.5%ED while neither a continuous or single cycle ED exposure caused this effect. Adult rats also had reduced SI following repeated withdrawals from both 2.5% and 3.5%ED. This effect was present up to 1 week following the final withdrawal in adolescents but returned to baseline by 1 day in adults. CP‐154,526, buspirone, or flumazenil prevented this reduction in SI in adolescent rats.

Conclusions: Adolescent rats exhibit sensitized anxiety‐like behavior following repeated withdrawals at ED concentrations similar to those used in adults. However, this effect is longer lasting in adolescent rats. Drugs modulating CRF, 5‐HT, or GABA systems during initial withdrawals prevent the development of anxiety‐like behavior otherwise manifest during a final withdrawal in adolescent rats.
Changes in the Episodic Memory and Executive Functions of Abstinent and Relapsed Alcoholics Over a 6‐Month Period
Authors: Pitel Anne Lise , Rivier Julia , Beaunieux Hélène , Vabret François , Desgranges Béatrice , Eustache Francis
Published: December 2008

Background:  It is still unclear whether episodic memory and executive functions capacities can return to normal in abstinent patients over a 6‐month period. Furthermore, the role of interim drinking in cognitive recovery is still not well known. Finally, further research is required to specify the predictive value of cognitive abilities at initial testing in the treatment outcome (abstinence or relapse). The aims of the present study were therefore to measure changes in episodic memory and executive functions over a 6‐month period in abstinent and relapsed alcoholics and to ascertain whether neuropsychological results at treatment entry can predict treatment outcome at follow‐up.

Methods:  Fifty‐four alcoholic patients and 54 matched control subjects performed baseline neuropsychological tasks assessing episodic memory, executive functions, the slave systems of working memory and attentional abilities. At the follow‐up session (i.e., 6 months later), episodic memory and 3 executive functions (inhibition, flexibility, and updating) were re‐examined in the alcoholic patients.

Results:  Results showed that over the 6‐month interval, the abstainers’ episodic memory and executive performances had returned to normal, whereas the relapsers performed lower than before in the flexibility task. Episodic memory and executive functions recovery was correlated, in abstainers, with drinking history and age respectively. Finally, there was no significant difference regarding neuropsychological scores at baseline between abstainers and relapsers.

Discussion:  Over the 6‐month interval, abstainers normalized episodic memory and executive performances whereas relapsers obtained executive results which were more severely impaired, emphasizing the influence of interim drinking on cognitive changes. Episodic memory, executive functions, the slave systems of working memory and attentional abilities did not appear to be reliable predictors of treatment outcome over a 6‐month interval.
A Sarcocystid Misidentified as Hepatozoon didelphydis: Molecular Data from a Parasitic Infection in the Blood of the Southern Mouse Opossum (Thylamys elegans) from Chile
Authors: MERINO SANTIAGO , VÁSQUEZ RODRIGO A. , MARTÍNEZ JAVIER , CELIS‐DIEZ JUAN L. , MARTÍNEZ‐DE LA PUENTE JOSUÉ , MARÍN‐VIAL PAULA , SÁNCHEZ‐MONSALVEZ INOCENCIA , PEIRCE MICHAEL A.
Published: December 2008

ABSTRACT. The blood of 21 adult South American mouse opossums (Thylamys elegans) captured from April through August of 2005 in central Chile was examined for parasites. Light microscopic analysis of blood smears initially suggested that a highly pleomorphic Hepatozoon species typical of American opossums was infecting erythrocytes. Unexpectedly, amplification by PCR and sequencing of a DNA fragment of the small subunit rDNA combined with phylogenetic analyses indicated that the parasite is not a member of the suborder Adeleorina, which includes the Haemogregarina and Hepatozoon species, but that it is a clearly distinct member of the suborder Eimeriorina, which includes the cyst‐forming family Sarcocystidae. Therefore, a reclassification of this unusual intraerythrocytic apicomplexan will require additional life cycle, microscopic, and molecular analyses.
Phylogeny of Six Genera of the Subclass Haptoria (Ciliophora, Litostomatea) Inferred from Sequences of the Gene Coding for Small Subunit Ribosomal RNA
Authors: GAO SHAN , SONG WEIBO , MA HONGWEI , CLAMP JOHN C. , YI ZHENZHEN , AL‐RASHEID KHALED A. S. , CHEN ZIGUI , LIN XIAOFENG
Published: December 2008

ABSTRACT. The small subunit ribosomal RNA genes of nine species belonging to six genera of litostome ciliates, namely Amphileptus aeschtae, Chaenea teres, Chaenea vorax, Lacrymaria marina, Litonotus paracygnus, Loxophyllum sp.‐GD‐070419, Loxophyllum jini, Loxophyllum rostratum, and Phialina salinarum, were sequenced for the first time. Phylogenetic trees were constructed using different methods to assess the inter‐ and intra‐generic relationships of haptorians, of which Chaenea, Lacrymaria, Litonotus, and Phialina were analyzed for the first time based on molecular data. Monophyly of the order Pleurostomatida was strongly confirmed, and the two existing families of pleurostomatids, created on the basis of morphology, were confirmed by molecular evidence. Within the Pleurostomatida, Siroloxophyllum utriculariae occupied a well‐supported position basal to the Loxophyllum clade, supporting the separation of these genera from one another. Both the subclass Haptoria and the order Haptorida were partially unresolved, possibly paraphyletic assemblages of taxa in all analyses, creating doubts about the traditional placement of some haptorid taxa. The existing sequence of L. rostratum in GenBank (DQ411864) was conspicuously different from that of the isolate from Qingdao, China sequenced in the present work, indicating that they are different species. The isolate from Qingdao was verified as L. rostratum by morphological analysis, and the published morphology of existing GenBank record of L. rostratum is different from it. Based on both morphological and molecular evidence, the latter may be congeneric with an undescribed species of Loxophyllum from Guangdong Province, China.
Small‐molecule peptides inhibit Z α1‐antitrypsin polymerization
Authors: Chang Yi‐Pin , Mahadeva Ravi , Chang Wun‐Shaing W. , Lin Sheng‐Chieh , Chu Yen‐Ho
Published: December 2008

The Z variant of α1‐antitrypsin (AT) polymerizes within the liver and gives rise to liver cirrhosis and the associated plasma deficiency leads to emphysema. In this work, a combinatorial approach based on the inhibitory mechanism of α1‐AT was developed to arrest its pathogenic polymerization. One peptide, Ac‐TTAI‐NH2, emerged as the most tight‐binding ligand for Z α1‐AT. Characterization of this tetrapeptide by gel electrophoresis and biosensor analysis revealed its markedly improved binding specificity and affinity compared with all previously reported peptide inhibitors. In addition, the peptide is not cytotoxic to lung cell lines. A model of the peptide‐protein complex suggests that the peptide interacts with nearby residues by hydrogen bonds, hydrophobic interactions, and cavity‐filling stabilization. The combinatorially selected peptide not only effectively blocks the polymerization but also promotes dissociation of the oligomerized α1‐AT. These results are a significant step towards the potential treatment of Z α1‐AT related diseases.
A model for small‐scale seed bank and standing vegetation connection along time
Authors: Caballero Idoia , Olano José M. , Loidi Javier , Escudero Adrián
Published: December 2008

Since inter‐annual climatic variability influences composition and structure of seed bank and extant vegetation, it is expected that it also affects the relationship between both compartments at small scales along time. We hypothesize that seed bank and aboveground vegetation are closely and sequentially linked at small spatial and time scales. We conducted a field spatially explicit investigation to explore the spatial and temporal relationship between both compartments. Abundance, composition and spatial structure at different small‐scales of seed bank and aboveground vegetation were analysed through 100 permanent plots during two consecutive (dry and wet) periods of growth. Following a conceptual transition path model, we analysed changes in correlation values in composition and spatial aggregation between both compartments along time including seasonal variations of seed bank. Shape of spatial structures were evaluated using partial Mantel correlograms. Annuals and perennials guilds were studied separately. During the wet year, annuals increased their aerial spatial aggregation and cover, whereas the opposite happened for perennials. Density and spatial aggregation of the seed bank increased for both guilds in the two seasons following the rain period, especially in annuals. The clumped structure of the transient seed bank is a consequence of the addition of spatial structure of extant vegetation and the persistent seed bank. Expression of the persistent seed bank is much lower during the dry period for the annual guild. In spite of the strong yearly variability, the community maintained a highly structured spatiotemporal pattern. The mechanisms promoting this stability differed for annual and perennial guilds. Temporal persistence in perennials relied mainly in established plants longevity, whereas annual guild persistence depended solely on seed bank. This tight structure was coherent with the existence of successional dynamics in the community, although persistent seed bank could moderate the pace. Longer term studies of seed bank–standing vegetation dynamics are required to fully understand this process.
Repeated measures of macular pigment optical density to test reproducibility of heterochromatic flicker photometry
Authors: Hagen Stefan , Krebs Ilse , Glittenberg Carl , Binder Susanne
Published: December 2008

Purpose:  To report the reproducibility of macular pigment optical density (MPOD) values assessed with heterochromatic flicker photometry (HFP) in healthy individuals.

Methods:  Twenty‐four volunteers from our department underwent MPOD testing of both eyes by flicker photometry on three separate occasions. To test reproducibility of MPOD, the coefficient of variance was calculated separately for right and left eyes. In addition, we investigated MPOD averages of right and left eyes and interocular correlations (Pearson’s r) at every visit.

Results:  The mean MPODs at the first visit were 0.61 ± 0.24 and 0.72 ± 0.27 in right and left eyes, respectively. Mean values of 0.58 ± 0.29 and 0.60 ± 0.21 (second visit) and 0.62 ± 0.27 and 0.63 ± 0.24 (third visit) were assessed for right and left eyes, respectively. Differences of the mean values between eyes were not significant. Correlations were weak at visits one and two (r = 0.49, p < 0.014 and r = 0.43, p < 0.038, respectively) and moderate at visit three (r = 0.58, p < 0.003). The coefficients of variance were 36.1% and 23% for right and left eyes, respectively.

Conclusion:  Our mean MPODs are higher and the interocular correlations weaker compared to the literature. The coefficient of variance in both eyes is high and does not imply good reproducibility of obtained MPOD values.
Freezing-Induced Fluid-Matrix Interaction in Poroelastic Material
Authors: Han Bumsoo , Miller Jeffrey D. , Jung Jun K.
Published: December 2008

Freezing of biological tissue is emerging in various biomedical applications. The success of these applications requires precise control of the tissue functionality, which is closely associated with the microstructure of the extracellular matrix (ECM). In the present study, the spatiotemporal effects of freezing on the ECM were experimentally and theoretically investigated by approximating biological tissue as a poroelastic material saturated with interstitial fluid. The experiments with type I collagen gel showed that its matrix underwent two distinct levels of structural changes due to freezing: enlarged pore structure of the matrix and increased collagen fibril diameters. The extent of these changes was augmented as the freezing temperature was lowered. The theoretical model suggested that the interstitial fluid might be transported toward the unfrozen region from the phase change interface due to the volumetric expansion associated with the water-ice phase change, and the transported fluid could interact with the matrix and enlarge its pore structure. The model also illustrated the effects of matrix structural properties on this interaction including initial porosity, hydraulic conductivity, and elastic modulus. These results imply that an identical macroscopic freezing protocol may result in different microstructural alterations of poroelastic materials depending on the structural properties of the matrix. This may be relevant to understanding the tissue-type dependent outcomes of cryomedicine applications and be useful in designing cryomedicine applications for a wide variety of tissues.
Statistical Analysis of Interfacial Gap in a Cementless Stem FE Model
Authors: Park Youngbae , Choi DonOk , Hwang Deuk Soo , Yoon Yong-San
Published: December 2008

In cementless total hip arthroplasty, a fair amount of interfacial gap exists between the femoral stem and the bone. However, the effect of these gaps on the mechanical stability of the stem is poorly understood. In this paper, a finite element model with various interfacial gap definitions is used to quantify the effect of interfacial gaps on the primary stability of a Versys Fiber Metal Taper stem under stair climbing loads. In the first part, 500 random interfacial gap definitions were simulated. The resulting micromotion was approximately inversely proportional to the contact ratio, and the variance of the micromotion was greater with a lower contact ratio. Moreover, when the magnitude of the micromotion was compared between the gap definitions that had contact at a specific site and those that had no contact at that site, it was found that gaps located in the proximal-medial region of the stem surface had the most important effect on the micromotion. In a second trial, 17 gap definitions mimicking a gap pattern that has been observed experimentally were simulated. For a given contact ratio, the micromotion observed in the second trial was lower than the average result of those in the first, where the gaps were placed randomly. In either trial, when the contact ratio was higher than 40%, the micromotion showed no significant difference (first trial) or a gentle slope (−0.24μm∕% in the second trial) in relation to the contact ratio. Considering the reported contact ratios for properly implanted stems, variations in the amount of interfacial gap would not likely cause a drastic difference in micromotion, and this effect could be easily overshadowed by other clinical factors. In conclusion, differences in interfacial gaps are not expected to have a noticeable effect on the clinical micromotion of this cementless stem.
The Effect of Screw Pullout Rate on Screw Purchase in Synthetic Cancellous Bone
Authors: Zdero Rad , Schemitsch Emil H.
Published: December 2008

Clinically, orthopaedic fracture fixation constructs are mounted using screws inserted into cancellous bone, while biomechanical studies are increasingly using commercially available synthetic bones. The goal of this study was to examine the effect of screw pullout rate on cancellous bone screw purchase strength in synthetic cancellous bone. Sixty synthetic cancellous bone cubes (40×40×40mm3) each had one orthopaedic cancellous bone screw (major diameter=6.5mm) inserted to a depth of 30mm. Screws were extracted to obtain outcome measures of failure force, failure shear stress, failure energy, failure displacement, resistance force, and removal energy. The ten test groups (n=6 cubes per group) had screws extracted at pullout rates of 1mm∕min, 2.5mm∕min, 5mm∕min, 7.5mm∕min, 10mm∕min, 20mm∕min, 30mm∕min, 40mm∕min, 50mm∕min, and 60mm∕min. The aggregate average results for failure force, failure stress, failure energy, failure displacement, resistance force, and postfailure removal energy for combined pullout rates were, respectively, 984.8±63.9N, 3.5±0.2MPa, 298.3±41.7J, 0.53±0.08mm, 453.8±19.6N, and 5420.1±489.7J. Most statistical differences (40 of 47) involved either the 5mm∕min or the 60mm∕min rates being compared to other rates. Failure force, failure stress, and resistance force increased and were highly linearly correlated with pullout rate (R2=0.78, 0.76, and 0.74, respectively). Failure energy, failure displacement, and removal energy were relatively unchanged over the pullout range tested, yielding low correlation coefficients (R2<0.05). Failure force, failure stress, and resistance force were affected by bone screw pullout rate in synthetic cancellous bone, while failure energy, failure displacement, and removal energy remained unchanged. This is the first study to perform an extensive investigation of cancellous bone screw pullout rate in synthetic cancellous bone.
Comment on "Declining Wild Salmon Populations in Relation to Parasites from Farm Salmon"
Authors: Riddell Brian E. , Beamish Richard J. , Richards Laura J. , Candy John R.
Published: December 2008

Krkošek
et al
. (Reports, 14 December 2007, p. 1772) claimed that sea lice spread from salmon farms placed wild pink salmon populations “on a trajectory toward rapid local extinction.” Their prediction is inconsistent with observed pink salmon returns and overstates the risks from sea lice and salmon farming.
Response to Comment on "Declining Wild Salmon Populations in Relation to Parasites from Farm Salmon"
Authors: Krkošek Martin , Ford Jennifer S. , Morton Alexandra , Lele Subhash , Lewis Mark A.
Published: December 2008

We evaluated the effect of sea lice (
Lepeophtheirus salmonis
) infestations on wild pink salmon (
Oncorhynchus gorbuscha
) populations in the Broughton Archipelago, British Columbia. Riddell
et al
. suggest that we ignored factors and selectively used data. Here, we clarify misunderstandings and provide analysis to test the strength of our conclusions.
Matching Glass-Forming Ability with the Density of the Amorphous Phase
Authors: Li Y. , Guo Q. , Kalb J. A. , Thompson C. V.
Published: December 2008

The density of the amorphous phase of metals is generally thought to be related to glass formation, but this correlation has not been demonstrated experimentally to date. In this work, systematic deflection measurements using microcantilevers and a combinatorial deposition method show a correlation between glass-forming ability and the density change upon crystallization over a broad compositional range in the copper-zirconium binary system. Distinct peaks in the density of the amorphous phase were found to correlate with specific maxima in the critical thickness for glass formation. Our findings provide quantitative data for the development of structural models of liquids that are readily quenched to the amorphous state. The experimental method developed in this work can facilitate the search for new glass-forming alloys.
Orbital Identification of Carbonate-Bearing Rocks on Mars
Authors: Ehlmann Bethany L. , Mustard John F. , Murchie Scott L. , Poulet Francois , Bishop Janice L. , Brown Adrian J. , Calvin Wendy M. , Clark Roger N. , Marais David J. Des , Milliken Ralph E. , Roach Leah H. , Roush Ted L. , Swayze Gregg A. , Wray James J.
Published: December 2008

Geochemical models for Mars predict carbonate formation during aqueous alteration. Carbonate-bearing rocks had not previously been detected on Mars' surface, but Mars Reconnaissance Orbiter mapping reveals a regional rock layer with near-infrared spectral characteristics that are consistent with the presence of magnesium carbonate in the Nili Fossae region. The carbonate is closely associated with both phyllosilicate-bearing and olivine-rich rock units and probably formed during the Noachian or early Hesperian era from the alteration of olivine by either hydrothermal fluids or near-surface water. The presence of carbonate as well as accompanying clays suggests that waters were neutral to alkaline at the time of its formation and that acidic weathering, proposed to be characteristic of Hesperian Mars, did not destroy these carbonates and thus did not dominate all aqueous environments.
Shock-Wave Exploration of the High-Pressure Phases of Carbon
Authors: Knudson M. D. , Desjarlais M. P. , Dolan D. H.
Published: December 2008

The high–energy density behavior of carbon, particularly in the vicinity of the melt boundary, is of broad scientific interest and of particular interest to those studying planetary astrophysics and inertial confinement fusion. Previous experimental data in the several hundred gigapascal pressure range, particularly near the melt boundary, have only been able to provide data with accuracy capable of qualitative comparison with theory. Here we present shock-wave experiments on carbon (using a magnetically driven flyer-plate technique with an order of magnitude improvement in accuracy) that enable quantitative comparison with theory. This work provides evidence for the existence of a diamond-bc8-liquid triple point on the melt boundary.
Representation of Geometric Borders in the Entorhinal Cortex
Authors: Solstad Trygve , Boccara Charlotte N. , Kropff Emilio , Moser May-Britt , Moser Edvard I.
Published: December 2008

We report the existence of an entorhinal cell type that fires when an animal is close to the borders of the proximal environment. The orientation-specific edge-apposing activity of these “border cells” is maintained when the environment is stretched and during testing in enclosures of different size and shape in different rooms. Border cells are relatively sparse, making up less than 10% of the local cell population, but can be found in all layers of the medial entorhinal cortex as well as the adjacent parasubiculum, often intermingled with head-direction cells and grid cells. Border cells may be instrumental in planning trajectories and anchoring grid fields and place fields to a geometric reference frame.
To Make Aire Dance
Authors: Ash Caroline
Published: December 2008

The Tragedy of Thomas Hobbes
.
By Adriano Shaplin
. Royal Shakespeare Theatre, Wilton's Music Hall, London.

This history play on the emergence of science in the 17th century and the growth of public scientific demonstrations and debate pits the philosopher Hobbes against a group led by Robert Hooke and Robert Boyle.
Heightened Cytotoxic Responses and Impaired Biogenesis Contribute to Early Pathogenesis in the Oral Mucosa of Simian Immunodeficiency Virus-Infected Rhesus Macaques
Authors: George Michael D. , Verhoeven David , Sankaran Sumathi , Glavan Tiffany , Reay Elizabeth , Dandekar Satya
Published: December 2008

Simian immunodeficiency virus (SIV) infection disseminated into the oropharyngeal tissues of rhesus macaques 6 weeks following intravenous inoculation. Severe local CD4+T-cell depletion coincided with increases in NK cell and proinflammatory biomarkers and the disruption of growth-associated gene transcription, demonstrating the rapid establishment of pathogenesis in the oral mucosa.
Predicting the Impact of Blocking Human Immunodeficiency Virus Type 1 Nef In Vivo
Authors: Wick W. David , Gilbert Peter B. , Yang Otto O.
Published: December 2008

Human immunodeficiency virus type 1 (HIV-1) Nef is a multifunctional protein that confers an ability to evade killing by cytotoxic T lymphocytes (CTLs) as well as other advantages to the virus in vivo. Here we exploited mathematical modeling and related statistical methods to estimate the impact of Nef activity on viral replication in vivo in relation to CTLs. Our results indicate that downregulation of major histocompatibility complex class I (MHC-I) A and B by wild-type Nef confers an advantage to the virus of about 82% in decreased CTL killing efficiency on average, meaning that abolishing the MHC-I downregulation function of Nef would increase killing by more than fivefold. We incorporated this estimate, as well as prior estimates of replicative enhancement by Nef, into a previously published model of HIV-1 and CTLs in vivo (W. D. Wick, O. O. Yang, L. Corey, and S. G. Self, J. Virol. 79:13579-13586, 2005), generalized to permit CTL recognition of multiple epitopes. A sequence database analysis revealed that 92.9% of HIV-1 epitopes are A or B restricted, and a previous study found an average of about 19 epitopes recognized (M. M. Addo et al., J. Virol. 77:2081-2092, 2003). We combined these estimates in the model in order to predict the impact of inhibiting Nef function in the general (chronically infected) population by a drug. The predicted impact on viral load ranged from negligible to 2.4 orders of magnitude, depending on the effects of the drug and the CTL dynamical scenario assumed. We conclude that inhibiting Nef could make a substantial reduction in disease burden, lengthening the time before the necessity of undertaking combination therapy with other antiretroviral drugs.
Transmission and Long-Term Stability of Compensated CD8 Escape Mutations
Authors: Schneidewind Arne , Brumme Zabrina L. , Brumme Chanson J. , Power Karen A. , Reyor Laura L. , O'Sullivan Kristin , Gladden Adrianne , Hempel Ursula , Kuntzen Thomas , Wang Yaoyu E. , Oniangue-Ndza Cesar , Jessen Heiko , Markowitz Martin , Rosenberg Eric S. , Sékaly Rafick-Pierre , Kelleher Anthony D. , Walker Bruce D. , Allen Todd M.
Published: December 2008

Human immunodeficiency virus effectively evades CD8
+
T-cell responses through the development of CD8 escape mutations. Recent reports documenting reversion of transmitted mutations and the impact of specific escape mutations upon viral replication suggest that complex forces limit the accumulation of CD8 escape mutations at the population level. However, the presence of compensatory mutations capable of alleviating the impact of CD8 escape mutations on replication capacity may enable their persistence in an HLA-mismatched host. Herein, we illustrate the long-term stability of stereotypic escape mutations in the immunodominant HLA-B27-restricted epitope KK10 in p24/Gag following transmission when accompanied by a specific compensatory mutation.
ORF30 and ORF34 Are Essential for Expression of Late Genes in Murine Gammaherpesvirus 68
Authors: Wu Ting-Ting , Park Tina , Kim Hana , Tran Thuy , Tong Leming , Martinez-Guzman DeeAnn , Reyes Nichole , Deng Hongyu , Sun Ren
Published: December 2008

A hallmark of productive infection by DNA viruses is the coupling of viral late gene expression to genome replication. Here we report the identification of open reading frame 30 (ORF30) and ORF34 as viral
trans
factors crucial for activating late gene transcription following viral DNA replication during lytic infection of murine gammaherpesvirus 68 (MHV-68). The mutant virus lacking either ORF30 or ORF34 underwent normal DNA replication but failed to express viral late gene transcripts, leading to nonproductive infection. In a reporter assay system, ORF30 and ORF34 were required for MHV-68 to activate the viral late gene promoters. Furthermore, studies using chromatin immunoprecipitation assays showed that the recruitment of RNA polymerase II to the viral late promoters during lytic infection was significantly reduced in the absence of ORF30 or ORF34. Together, the results suggest that ORF30 and ORF34 may play an important role in the assembly of the transcription initiation complex at the late gene promoters. Our discovery of the viral mutants that uncouple late gene transcription from DNA replication lays an important foundation to dissect the mechanism of this critical step of gene expression regulation.
Prevalence and risk factors for diabetic retinopathy: a population-based assessment from Theni District, south India
Authors: Namperumalsamy P , Kim R , Vignesh T P , Nithya N , Royes J , Gijo T , Thulasiraj R D , Vijayakumar V
Published: December 2008

Aims

To estimate the prevalence of diabetic retinopathy (DR) and the possible risk factors associated with DR, in a population of south India.

Methods

A cross-sectional sample of subjects aged 30 years and older was selected using a cluster sampling technique from Theni district of Tamilnadu state. Eligible subjects were identified through a door-to-door survey and fasting blood glucose estimation. History of diabetes was elicited, and height, weight and blood pressure were measured for all subjects. Ocular examinations including visual acuity and anterior and posterior segment examinations were performed at preselected sites within clusters.

Results

Among the 25 969 persons screened for diabetes mellitus (DM), 2802 (10.8%) (95% CI 9.3 to 12.2%) were found to have DM. DR was detected in 298 (1.2%) of 25 969 subjects. The age–gender-adjusted prevalence of DR is 0.05% (95% CI 0.04 to 0.06%) for rural and 1.03% (95% CI 0.89 to 1.12%) for urban areas. The overall age–gender-cluster adjusted prevalence of DR was 0.74% (95% CI 0.66 to 0.83%). Diabetic retinopathy was present in 12.2% (95% CI 10.4 to 14.1%) of the DM population.

Conclusion

Adequate training of ophthalmologists in treating DR and improvement in eye-care infrastructure are needed to tackle this major public health problem in India.
Interpersonal conflicts at work as a predictor of self-reported health outcomes and occupational mobility
Authors: De Raeve L , Jansen N W H , van den Brandt P A , Vasse R , Kant IJ
Published: December 2008

Objectives:

The aim of this prospective study was to examine the relationship between interpersonal conflicts at work and subsequent self-reported health outcomes (self-reported general health, need for recovery, and prolonged fatigue) and occupational mobility (internal mobility ie, changing job function, and external mobility ie, changing employers).

Methods:

Data from the Maastricht Cohort Study on fatigue at work (n = 5582 for co-worker conflict; n = 5530 for supervisor conflict) were used. Interpersonal conflict with either co-workers or supervisors was assessed between baseline and 1-year follow-up. Outcomes were studied every 4 months between 1-year and 2-year follow-up. Logistic regression analyses using generalised estimating equations were conducted for each of the dichotomous outcomes, while controlling for demographic factors, the presence of a long-term illness, other workplace stressors, coping, and outcome at baseline. Analyses were conducted for men only.

Results:

At baseline, conflicts with co-workers occurred in 7.2% of the study population, while conflicts with supervisors occurred in 9.5% of the study population. In general, this study showed that co-worker conflict was a statistically significant risk factor for the onset of an elevated need for recovery, prolonged fatigue, poor general health and external occupational mobility. Supervisor conflict was a significant risk factor for the onset of an elevated need for recovery, prolonged fatigue, external occupational mobility, and internal occupational mobility.

Conclusions:

The results of this study indicate a possible causal relationship between interpersonal conflicts at work and self-reported health and occupational mobility. Given the considerable impact of interpersonal conflicts at work on the individual worker and on the organisation, and the fact that interpersonal conflicts at work are highly prevalent, these findings underline the need for interventions aimed at preventing the occurrence of interpersonal conflicts at work, or at least reducing the harmful effects on both the employee and the organisation.
Weathering regime and geochemical conditions in a polar desert environment, Haughton impact structure region, Devon Island, Canada
Authors: Lacelle Denis , Juneau Véronique , Pellerin André , Lauriol Bernard , Clark Ian D.
Published: December 2008

This study examines the physical and geochemical properties of near-surface sediments, as well as the geochemical and stable O–H–C isotope composition of (ground)surface waters in and around the Haughton impact structure region (Devon Island, Nunavut) to determine the types of weathering (mechanical, (bio)chemical) and their relative contribution in this polar desert environment. The surface sediments collected from the Allen Bay and Thumb Mountain formations surrounding the impact crater are dominated by sand-sized particles; whereas the impact melt breccias inside the crater have a greater abundance of silt-sized particles. The subsurface sediments in the Allen Bay formation show a near equal amount of sand- and silt-sized particles. However, the micromorphologies of the sand-sized particles collected at the surface revealed that these grains, irrespective of the local geology, were heavily fractured. By contrast, fractures and rounded pits are observed on the surface of the sand grains located within the active layer; whereas those located just above the permafrost table have only rounded cavities on their surface. The (ground)waters also show variations in their solute concentration with depth; the highest concentrations being found in the groundwaters near the top of permafrost. Taken together, these observations suggest that there is a progressive evolution from a mechanically dominated weathering regime near the surface, to increasing chemical weathering with depth. The transition from mechanical weathering near the surface to increasing chemical weathering with depth can be attributed to the decreasing frequency and intensity of mechanical weathering processes (i.e., frost action, wetting–drying, thermal dilation) with depth, and to the presence of permafrost, which allows a greater availability of water for chemical aqueous reactions at the base of the active layer.
Heat-shock-induced oxidative stress and antioxidant response in Aspergillus niger 26
Authors: Abrashev Radoslav I. , Pashova Svetlana B. , Stefanova Lilyana N. , Vassilev Spassen V. , Dolashka-Angelova Pavlina A. , Angelova Maria B.
Published: December 2008

To extend the knowledge about the relationship between heat shock and oxidative stress in lower eukaryotes, the filamentous fungus Aspergillus niger 26 was chosen as a model system. Here, the response of A. niger cells to heat shock is reported. The temperature treatment significantly increased the levels of reactive oxygen species, superoxide anions (O2•–), and hydrogen peroxide and the rate of cyanide-resistant respiration as a marker of oxidative stress. Enhanced reactive oxygen species generation coincided with an increase in the content of oxidative damaged protein and in the accumulation of the storage carbohydrates trehalose and glycogen. Thermal survival of the A. niger cells corresponded to a significant increase in the levels of the antioxidant enzymes superoxide dismutase and catalase for all variants. These observations suggest that heat and oxidative stress have a common cellular effect.
Molecular bacterial diversity and distribution in waste from a steel plant
Authors: Freitas Dulcecleide B. , Reis Mariana P. , Freitas Leandro M. , Assis Paulo S. , Chartone-Souza Edmar , Nascimento Andréa M. A.
Published: December 2008

We characterized the bacterial diversity of newly produced steelmaking wastes (NPSW) and steelmaking wastes deposited (SWD) in a restricted land area, generated by the siderurgic industry, using the 16S rDNA clone library approach. A total of 212 partial-length sequences were analyzed, revealing 123 distinct operational taxonomic units (OTUs) determined by the DOTUR program to 97% sequence similarity. Phylogenetic analysis of bacterial 16S rDNA sequences from the NPSW and SWD libraries demonstrated that Gammaproteobacteria, Betaproteobacteria, Alphaproteobacteria, Actinobacteria, Planctomycetes, Firmicutes, and Bacteroidetes were represented in both libraries. Deltaproteobacteria, Acidobacteria, Chloroflexi, Deinococcus-thermus, Gemmatimonadetes, and candidate divisions OP10 and OD1 were only present in the SWD library, and Nitrospira was only present in the NPSW library. The abundance of sequences affiliated with Gammaproteobacteria was high in both libraries. Six previously unclassified OTUs may represent novel taxa. Based on diversity indices (Simpson, Shannon–Weaver, Chao1, and ACE), the SWD library had a higher diversity. LIBSHUFF comparisons of the composition of the 2 libraries showed that they were significantly different. These results indicate that the bacterial communities in steelmaking wastes present high phylogenetic diversity and complexity. A possible association between the functional diversity and the bacterial communities’ complexity requires further phenotypic investigation.