bluuebunny/crossref_metadata_2025 huggingface dataset:
Adaptive radiation in Lesser Antillean lizards: molecular phylogenetics and species recognition in the Lesser Antillean dwarf gecko complex, Sphaerodactylus fantasticus
Authors: THORPE R. S. , JONES A. G. , MALHOTRA A. , SURGET‐GROBA Y.
Published: February 2008

The time associated with speciation varies dramatically among lower vertebrates. The nature and timing of divergence is investigated in the fantastic dwarf gecko Sphaerodactylus fantasticus complex, a nominal species that occurs on the central Lesser Antillean island of Guadeloupe and adjacent islands and islets. This is compared to the divergence in the sympatric anole clade from the Anolis bimaculatus group. A molecular phylogenetic analysis of numerous gecko populations from across these islands, based on three mitochondrial DNA genes, reveals several monophyletic groups occupying distinct geographical areas, these being Les Saintes, western Basse Terre plus Dominica, eastern Basse Terre, Grand Terre, and the northern and eastern islands (Montserrat, Marie Galante, Petite Terre, Desirade). Although part of the same nominal species, the molecular divergence within this species complex is extraordinarily high (27% patristic distance between the most divergent lineages) and is compatible with this group occupying the region long before the origin of the younger island arc. Tests show that several quantitative morphological traits are correlated with the phylogeny, but in general the lineages are not uniquely defined by these traits. The dwarf geckos show notably less nominal species‐level adaptive radiation than that found in the sympatric southern clade of Anolis bimculatus, although both appear to have occupied the region for a broadly similar period of time. Nevertheless, the dwarf gecko populations on Les Saintes islets are the most morphologically distinct and are recognized as a full species (Sphaerodactylus phyzacinus), as are anoles on Les Saintes (Anolis terraealtae).
Stellar contents and star formation in the young open cluster Stock 8
Authors: Jose Jessy , Pandey A. K. , Ojha D. K. , Ogura K. , Chen W. P. , Bhatt B. C. , Ghosh S. K. , Mito H. , Maheswar G. , Sharma Saurabh
Published: February 2008

We present UBVIc CCD photometry of the young open cluster Stock 8 with the aim of studying its basic properties such as the amount of interstellar extinction, distance, age, stellar contents and initial mass function (IMF). We also studied the star formation scenario in this region. From optical data, the radius of the cluster is found to be ∼6 arcmin (∼3.6 pc) and the reddening within the cluster region varies from E(B−V) = 0.40 to 0.60 mag. The cluster is located at a distance of 2.05 ± 0.10 kpc. Using Hα slitless spectroscopy and Two Micron All Sky Survey (2MASS) near-infrared (NIR) data we identified Hα emission and NIR-excess young stellar objects (YSOs), respectively. From their locations in the colour–magnitude diagrams, majority of them seem to have ages between 1 and 5 Myr. The spread in their ages indicate a possible non-coeval star formation in the cluster. Massive stars in the cluster region reveal an average age of ≤2 Myr. In the cluster region (r≤ 6 arcmin) the slope of the mass function (MF), Γ, in the mass range ∼1.0 ≤M/M⊙ < 13.4 can be represented by a power law having a slope of −1.38 ± 0.12, which agrees well with Salpeter value (−1.35). In the mass range 0.3 ≤M/M⊙ < 1.0, the MF is also found to follow a power law with a shallower slope of Γ=−0.58 ± 0.23 indicating a break in the slope of the IMF at ∼1 M⊙. The slope of the K-band luminosity function for the cluster (r≤ 6 arcmin) is found to be 0.31 ± 0.02, which is smaller than the average value (∼0.4) obtained for embedded star clusters.

A significant number of YSOs are distributed along a Nebulous Stream towards the east side of the cluster. A small cluster is embedded in the Nebulous Stream. The YSOs lying in the Nebulous Stream and in the embedded cluster are found to be younger than the stars in the cluster Stock 8. The radio continuum, MSX, IRAS mid- and far-infrared maps and the ratio of [S ii]/Hα intensities indicate that the eastern region of Stock 8 is ionization bounded whereas the western region is density bounded. The morphology seems to indicate that the ionization/shock front caused by the ionizing sources located in the Stock 8 region and westwards of Stock 8 has not reached the Nebulous Stream. It appears that star formation activity in the Nebulous Stream and embedded cluster may be independent from that of Stock 8.
Distinguishing four fundamental approaches to the evolution of helping
Authors: BSHARY R. , BERGMÜLLER R.
Published: February 2008

The evolution and stability of helping behaviour has attracted great research efforts across disciplines. However, the field is also characterized by a great confusion over terminology and a number of disagreements, often between disciplines but also along taxonomic boundaries. In an attempt to clarify several issues, we identify four distinct research fields concerning the evolution of helping: (1) basic social evolution theory that studies helping within the framework of Hamilton’s inclusive fitness concept, i.e. direct and indirect benefits, (2) an ecological approach that identifies settings that promote life histories or interaction patterns that favour unconditional cooperative and altruistic behaviour, e.g. conditions that lead to interdependency or interactions among kin, (3) the game theoretic approach that identifies strategies that provide feedback and control mechanisms (protecting from cheaters) favouring cooperative behaviour (e.g. pseudo‐reciprocity, reciprocity), and (4) the social scientists’ approach that particularly emphasizes the special cognitive requirements necessary for human cooperative strategies. The four fields differ with respect to the ‘mechanisms’ and the ‘conditions’ favouring helping they investigate. Other major differences concern a focus on either the life‐time fitness consequences or the immediate payoff consequences of behaviour, and whether the behaviour of an individual or a whole interaction is considered. We suggest that distinguishing between these four separate fields and their complementary approaches will reduce misunderstandings, facilitating further integration of concepts within and across disciplines.
Go east: phylogeographies of Mauremys caspica and M. rivulata– discordance of morphology, mitochondrial and nuclear genomic markers and rare hybridization
Authors: FRITZ U. , AYAZ D. , BUSCHBOM J. , KAMI H. G. , MAZANAEVA L. F. , ALOUFI A. A. , AUER M. , RIFAI L. , ŠILIĆ T. , HUNDSDÖRFER A. K.
Published: February 2008

In recent years many cases of hybridization and introgression became known for chelonians, requiring a better understanding of their speciation mechanisms. Phylogeographic investigations offer basic data for this challenge. We use the sister species Mauremys caspica and M. rivulata, the most abundant terrapins in the Near and Middle East and South‐east Europe, as model. Their phylogeographies provide evidence that speciation of chelonians fits the allopatric speciation model, with both species being in the parapatric phase of speciation, and that intrinsic isolation mechanisms are developed during speciation. Hybridization between M. caspica and M. rivulata is very rare, suggesting that the increasing numbers of hybrids in other species are caused by human impact on environment (breakdown of ecological isolation). Genetic differentiation within M. caspica and M. rivulata resembles the paradigm of southern genetic richness and northern purity of European biota. However, in west Asia this pattern is likely to reflect dispersal and vicariance events older than the Holocene. For M. caspica three distinct Pleistocene refuges are postulated (Central Anatolia, south coast of Caspian Sea, Gulf of Persia). Morphologically defined subspecies within M. caspica are not supported by genetic data. This is one of the few studies available about the phylogeography of west and central Asian species.
THE EFFECT OF REGULAR AND IRREGULAR SHEAR LIPS ON FATIGUE CRACK GROWTH IN Al 2024
Authors: Zuidema J. , Krabbe J. P.
Published: February 2008

Abstract— Multiple underloads and overloads with constant ΔK were carried out on centre‐cracked tension specimens. It was found that when shear lips develop, underloads or overloads affect the crack growth rate da/dN and the subsequent retardation. The appearance of the shear lip fracture surfaces depends on the frequency. At higher frequencies a greater number of rough shear lip fracture surfaces will develop, while at lower frequencies there is a tendency towards smooth shear lips. The amount of crack closure differs in each case. It was found that the type of shear lip, rough or smooth, can be related to the effect on da/dN during and after underloads. The effect of rough and smooth shear lip growth was investigated in constant ΔK tests, performing these tests with and without crack closure.
A FRACTURE MECHANICS APPROACH FOR THE DEVELOPMENT OF REFRACTORY MATERIALS WITH REDUCED BRITTLENESS
Authors: Harmuth H. , Tschegg E. K.
Published: February 2008

Abstract— Ordinary ceramic refractories are used as lining material for industrial pyro‐processes. A high resistance to mechanical failure from an imposed strain or thermal shock is usually termed “flexibility”. A scientific approach to enhance this property is hindered by the fact that there is a lack of understanding, definition and measurement of this parameter in relation to its physical basis.

Wedge splitting tests were performed on a variety of typically shaped refractories together with standard procedures. This type of test enables stable crack propagation even for relatively large specimen dimensions that are necessary due to the size effect. High “flexibility” proved to be achievable in low brittleness materials and can be characterised by a brittleness number, the characteristic length or the thermal shock fracture resistance parameter according to Hasselman. A sufficient decrease of brittleness can be successfully achieved by the formation of precracks during the burning process which enhance the development of a fracture process zone. For a magnesia refractory (with additions of magnesia‐alumina spinel) a friction bridging mechanism plays an important role in reducing brittleness.
‘Intentional repetition’ and learning style: Increasing efficient and cohesive interaction in asynchronous online discussions
Authors: Topçu Abdullah
Published: February 2008

This study verified the efficacy of the intentional repetition technique in improving interaction in asynchronous online discussions by taking into account the learning styles of the participants. A conceptual framework served for the development of the technique, which conceptualises efficient and cohesive interaction on a continuum of process that move from social presence to production of an artefact. Sixty‐one university students participated in the study. A quasi‐experimental research design was used. The subjects, who were assigned randomly into two groups, were tested using Kolb's learning style inventory. The results showed that the experimental group exposed to the intentional repetition technique produced significantly better interaction than the control group, regardless of their learning styles, which had no significant effect on the interaction. Moreover, there was no interaction effect between the learning styles and the treatment. The implications arising from these results identify various suggestions for increasing the coherence and depth of the interaction amongst students in asynchronous online discussions.
The Evolution of Enterprise Unionism in Japan: A Socio‐Political Perspective
Authors: Jeong Dae Yong , Aguilera Ruth V.
Published: February 2008

This article proposes an alternative framework for understanding enterprise unionism by emphasizing political dynamics and the role of the state in labour relations. Our framework delineates the strategic behaviour patterns of each of the tripartite IR actors under collective bargaining. It maintains that the initial period of the collective bargaining era constituted a critical juncture for state labour policy that occurred in distinctive ways in different countries and that these differences played a central role in shaping the different union structures in the following decades. Our historical analysis shows that unlike its Western counterparts, the Japanese state was able to eradicate the horizontal union movement at the onset of the collective bargaining era because of its advantages as a late developer and Cold War politics, which resulted in enterprise unionism in Japan.
Errors Are Aversive
Authors: Hajcak Greg , Foti Dan
Published: February 2008

The error-related negativity (ERN) is a negative deflection in the event-related potential that is maximal approximately 50 ms after the commission of an error. The ERN is generated in the anterior cingulate cortex, a region of the medial prefrontal cortex implicated in both cognitive and emotional processing. Affective and motivational variables influence the magnitude of the ERN, which suggests that the ERN may relate to emotional or motivational aspects of error detection. In the present study, we evaluated the possibility that errors prime defensive motivational responses, and that the ERN may predict the magnitude of defensive reactivity after errors. We found that (a) the defensive startle response was larger following errors than following correct responses, and (b) the magnitude of the ERN predicted the degree of startle potentiation following errors. Thus, response errors prime defensive motivation—and the ERN predicts individual differences in the aversive response to errors.
Effects of Fluency on Psychological Distance and Mental Construal (or Why New York Is a Large City, but New York Is a Civilized Jungle)
Authors: Alter Adam L. , Oppenheimer Daniel M.
Published: February 2008

People construe the world along a continuum from concretely (focusing on specific, local details) to abstractly (focusing on global essences). We show that people are more likely to interpret the world abstractly when they experience cognitive disfluency, or difficulty processing stimuli in the environment, than when they experience cognitive fluency. We observed this effect using three instantiations of fluency: visual perceptual fluency (Study 1b), conceptual priming fluency (Study 2b), and linguistic fluency (Study 3). Adopting the framework of construal theory, we suggest that one mechanism for this effect is perceivers' tendency to interpret disfluently processed stimuli as farther from their current position than fluently processed stimuli (Studies 1a and 2a).
The Negative Consequences of Threat
Authors: Krendl Anne C. , Richeson Jennifer A. , Kelley William M. , Heatherton Todd F.
Published: February 2008

This study used functional magnetic resonance imaging to identify the neural structures associated with women's underperformance on math tasks. Although women in a control condition recruited neural networks that are associated with mathematical learning (i.e., angular gyrus, left parietal and prefrontal cortex), women who were reminded of gender stereotypes about math ability did not recruit these regions, and instead revealed heightened activation in a neural region associated with social and emotional processing (ventral anterior cingulate cortex).
HISTORICITY AND TRANSCENDENTALITY: FOUCAULT, CAVAILLÈS, AND THE PHENOMENOLOGY OF THE CONCEPT
Authors: THOMPSON KEVIN
Published: February 2008

AbSTRACT

This paper is concerned with Foucault's historical methodology. It argues that the coherence of his project lies in its development of a set of tools for unearthing the historical principles that govern thought and practice in the epochs that have shaped the present age. Foucault claimed that these principles are, at once, transcendental and historical. Accordingly, the philosophical soundness of Foucault's project depends on his having developed a satisfactory way of passage between the absolutist purism of the transcendental and the mundane contingency of the historical. The paper shows that the key to seeing how Foucault achieved this desideratum lies in a surprising and largely unexplored methodological tradition that he himself explicitly acknowledged: Husserlian phenomenology as it was taken up, modifed, and practiced in the thought of the philosopher of logic and mathematics, Jean Cavaillès—what I call the phenomenology of the concept.

The essay has four parts. The first sketches the two most prominent lines of interpretation of Foucault's methodology and argues that both are inadequate, not least because they both dismiss Foucault's phenomenological heritage. The second part lays out the rudiments of the neglected strand of the phenomenological tradition inaugurated by Cavaillès's important critique and appropriation of Husserlian method. This serves, in turn, to set the stage for the third part that examines, first, Canguilhem's and then Foucault's distinct projects for grasping the transcendental within the historical, and the historical within the transcendental—their respective continuations of Cavaillès's phenomenology of the concept. The essay concludes with a brief consideration of the pathways that this way of reading Foucault opens up for understanding the nexus of power, knowledge, and subjectivation that came to define his work.
Bacterial mycophagy: definition and diagnosis of a unique bacterial–fungal interaction
Authors: Leveau Johan H. J. , Preston Gail M.
Published: February 2008

This review analyses the phenomenon of bacterial mycophagy, which we define as a set of phenotypic behaviours that enable bacteria to obtain nutrients from living fungi and thus allow the conversion of fungal into bacterial biomass. We recognize three types of bacterial strategies to derive nutrition from fungi: necrotrophy, extracellular biotrophy and endocellular biotrophy. Each is characterized by a set of uniquely sequential and differently overlapping interactions with the fungal target. We offer a detailed analysis of the nature of these interactions, as well as a comprehensive overview of methodologies for assessing and quantifying their individual contributions to the mycophagy phenotype. Furthermore, we discuss future prospects for the study and exploitation of bacterial mycophagy, including the need for appropriate tools to detect bacterial mycophagy in situ in order to be able to understand, predict and possibly manipulate the way in which mycophagous bacteria affect fungal activity, turnover, and community structure in soils and other ecosystems.

Contents

Summary
1

I.
What is (bacterial) mycophagy?
2

II.
Strategies for bacterial mycophagy
2

III.
Practical definitions of bacterial mycophagy
9

IV.
Future directions for the study of bacterial mycophagy
11

Acknowledgements
13

References
13
Can isotopic fractionation during respiration explain the 13C‐enriched sporocarps of ectomycorrhizal and saprotrophic fungi?
Authors: Boström B. , Comstedt D. , Ekblad A.
Published: February 2008

DOI: 10.1111/j.1469-8137.2007.02373.x
Effects of levetiracetam on EEG abnormalities in juvenile myoclonic epilepsy
Authors: Specchio Nicola , Boero Giovanni , Michelucci Roberto , Gambardella Antonio , Giallonardo Anna Teresa , Fattouch Jinane , Di Bonaventura Carlo , De Palo Alessia , Ladogana Marianna , Lamberti Paolo , Vigevano Federico , La Neve Angela , Specchio Luigi Maria
Published: February 2008

Summary

Purpose: A multicenter, prospective, long‐term, open‐label study to evaluate the effects of levetiracetam on electroencephalogram (EEG) abnormalities and photoparoxysmal response (PPR) of patients affected by juvenile myoclonic epilepsy (JME).

Methods: Forty‐eight patients with newly diagnosed JME (10) or resistant/intolerant (38) to previous antiepileptic drugs (AEDs) were enrolled. After an 8‐week baseline period, levetiracetam was titrated in 2 weeks to 500 mg b.i.d. and then increased to up to 3,000 mg/day. Efficacy parameters were based on the comparison and analysis of EEG interictal abnormalities classified as spikes‐and‐waves, polyspikes‐and‐waves, and presence of PPR. Secondary end point was evaluation of EEG and PPR changes as predictive factors of 12‐month seizure freedom.

Results: Overall, mean dose of levetiracetam was 2,208 mg/day. Mean study period was 19.3 ± 11.5 months (range 0.3–38). During the baseline period, interictal EEG abnormalities were detected in 44/48 patients (91.6%) and PPR was determined in 17/48 (35.4%) of patients. After levetiracetam treatment, 27/48 (56.2%) of patients compared to 4/48 (8.3%) in the baseline period (p < 0.0001) had a normal EEG. Thirteen of 17 (76.4%) (p < 0.0003) patients showed suppression of PPR. Cumulative probability of days with myoclonia (DWM) 12‐month remission was significantly higher (p < 0.05) in patients with a normal (normalized) EEG after levetiracetam treatment compared to those with an unchanged EEG.

Conclusions: Levetiracetam appeared to be effective in decreasing epileptiform EEG abnormalities, and suppressing the PPR in JME patients. This effect, along with a good efficacy and tolerability profile in this population further supports a first‐line role for levetiracetam in the treatment of JME
CORRELATED EVOLUTION OF GENOME SIZE AND CELL VOLUME IN DIATOMS (BACILLARIOPHYCEAE)1
Authors: Connolly Jessica A. , Oliver Matthew J. , Beaulieu Jeremy M. , Knight Charles A. , Tomanek Lars , Moline Mark A.
Published: February 2008

A correlation between genome size and cell volume has been observed across diverse assemblages of eukaryotes. We examined this relationship in diatoms (Bacillariophyceae), a phylum in which cell volume is of critical ecological and biogeochemical importance. In addition to testing whether there is a predictive relationship across extant species, we tested whether evolutionary divergences in genome size were correlated with evolutionary divergences in cell size (using independent contrasts). We estimated total DNA content for 16 diatom species using a flow cytometer and estimated cell volumes using critical dimensions with scaling equations. Our independent contrast analyses indicated a significant correlated evolution between genome size and cell volume. We then explored the evolutionary and ecological implications of this evolutionary relationship. Diatom cell volume is an important component of the global carbon cycle; therefore, understanding the mechanisms that drive diatom genome evolution has both evolutionary and ecological importance.
CILIATE‐SYMBIONT SPECIFICITY OF FRESHWATER ENDOSYMBIOTICCHLORELLA(TREBOUXIOPHYCEAE, CHLOROPHYTA)1
Authors: Summerer Monika , Sonntag Bettina , Sommaruga Ruben
Published: February 2008

The nature ofChlorellasymbioses in invertebrates and protists has attracted much interest, but the uncertain taxonomy of the algal partner has constrained a deeper ecological understanding of this symbiosis. We sequenced parts of the nuclear 18S rDNA, the internal transcribed spacer (ITS)‐1 region, and the chloroplast 16S rDNA of severalChlorellaisolated from pelagic ciliate species of different lakes,Paramecium bursariasymbionts, and free‐livingChlorellato elucidate phylogenetic relationships ofChlorella‐like algae and to assess their host specificity. Sequence analyses resulted in well‐resolved phylogenetic trees providing strong statistical support for a homogenous ‘zoochlorellae’ group of different ciliate species from one lake, but clearly differentChlorellain one of those ciliate species occurring in another lake. The twoChlorellastrains isolated from the same ciliate species, but from lakes having a 10‐fold difference in underwater UV transparency, also presented a distinct physiological trait, such as the ability to synthesize UV‐absorbing substances known as mycosporine‐like amino acids (MAAs). Algal symbionts of allP. bursariastrains of different origin resolved in one clade apart from the other ciliate symbionts but split into two distinct lineages, suggesting the existence of a biogeographic pattern. Overall, our results suggest a high degree of species specificity but also hint at the importance of physiological adaptation in symbioticChlorella.
Shear Bond Strength between Feldspathic CAD/CAM Ceramic and Human Dentine for Two Adhesive Cements
Authors: Graiff Lorenzo , Piovan Caterina , Vigolo Paolo , Mason Pier Nicola
Published: February 2008

Purpose: The purpose of this study was to evaluate the shear bond strength values between dentin substrate and a feldspathic ceramic material, based on computer‐assisted design and manufacture (CAD/CAM) technology, bonded together with two adhesive systems coupled with two dual‐polymerized luting agents. In addition, the effect of a silane coupling agent on bond strength was evaluated.

Material and Methods: Forty cylinders (6 mm in diameter, 5 mm thick) obtained from feldspathic ceramic blocks were cemented to the dentin of 40 recently extracted human teeth stored in saline solution at room temperature until testing. The specimens were randomly divided into four groups of ten teeth each. All specimens were airborne‐particle abraded and etched with hydrofluoric acid. In the first two groups (A1, A2) 20 ceramic cylinders were cemented using Excite DSC and Variolink II; in the A2 group the bonding surfaces were also treated with a silane coupling agent. In Groups B1 and B2, 20 ceramic cylinders were cemented using Scotchbond MPP and RelyX ARC; in the B2 group the bonding surfaces were also treated with a silane coupling agent as in Group A2. All cemented specimens were submitted to a shear bond strength test to check the strength of adhesion between the two substrates, dentin and ceramic. The data were analyzed with two‐way analysis of variance (p < 0.05).

Results: The mean values of the shear bond strength were (in MPa): 22 ± 7 for Excite DSC/Variolink II without silanization (Group A1); 29 ± 3 for Excite DSC/VariolinkII with silanization (Group A2); 22 ± 4 for Scotchbond MPP/RelyX ARC without silanization (Group B1); and 26 ± 5 for Scotchbond MPP/RelyX ARC with silanization (Group B2). Two‐way ANOVA revealed a significant effect of silanization (p < 0.01) and did not reveal any significant effect for either the bonding agents (p > 0.1) or the interaction between silanization and bonding agent (p > 0.05). Multinomial logit model did not show any statistical effects on the failure mode by the shear bond strength (p > 0.1). The hypotheses of independence between failure mode (cohesive vs. adhesive) and both the adhesive system (p < 0.05) and silanization (p < 0.05) were rejected by Pearson's chi‐square test.

Conclusion: Within the assumptions and limitations of this study (including the small number of specimens) both bonding systems used achieved good shear bond strength values. The application of a silane coupling agent on the ceramic surface after etching with hydrofluoric acid increased the adhesion strength with both adhesive materials used.
Inserting tunnelled hemodialysis catheters using elective guidewire exchange from nontunnelled catheters: Is there a greater risk of infection when compared with new‐site replacement?
Authors: CASEY Jonathan , DAVIES Jonathan , BALSHAW‐GREER Amanda , TAYLOR Nichola , CROWE Alexander V. , McCLELLAND Peter
Published: February 2008

The objective is to evaluate bacteremia outcomes and survival rates when using guidewire exchange to place tunnelled hemodialysis catheter (THDC) compared with a new‐site replacement. Retrospectively, all patients were identified who received a THDC between January 1, 2000 and January 1, 2007. Any THDC having received antibiotic line locks or tunnel‐to‐tunnel exchange were excluded. This left 408 THDC placed in 329 patients: 46 guidewire exchange, 362 new‐site replacement. Bacteremia rate from the new‐site insertion group was 3.0 per 1000 catheter days, the guidewire exchange group demonstrated a rate of 2.8 per 1000 catheter days. Local infection rates did not differ between the groups at 1.2 per 1000 catheters days. The actuarial catheter survival rates using Kaplan‐Meier survival analysis demonstrated no difference between the 2 groups. The placing of tunnelled cuffed hemodialysis catheters to replace temporary catheters using a guidewire exchange did not contribute to further episodes of sepsis and has the advantage of preserving venous access and minimizing invasive procedures for the patient.
Oral intake during hemodialysis: Is there an association with intradialytic hypotension?
Authors: BENAROIA Mark , ILIESCU Eduard A.
Published: February 2008

Oral intake (OI) of food and fluid has been associated with hypotension during hemodialysis (HD). Trials evaluating this relationship are small. The objective of this study was to quantify OI and to examine its association with hypotension during HD. This is a cross‐sectional retrospective chart review study of 3 consecutive HD runs (dialysate iCa=1.25 mmol/L) in 126 stable HD patients (n=378). For each run, the calculation for OI=total ultrafiltration−(net weight loss+IV fluids given). Hypotension was defined as a systolic blood pressure of <100 mmHg at any point during the run. The mean age of the patients was 60.9 years, 38.2% were female, 30.2% had diabetes mellitus, and the majority were Caucasian. The mean (SD) OI was 0.27 (0.352) L/run, range −1.061 to 1.901 L/run, with a normal distribution. In bivariate analysis, there was no correlation of OI with systolic blood pressure, diastolic blood pressure, or mean blood pressure (BP), and the mean OI did not differ among runs with hypotension (n=78) compared with uncomplicated runs (p=0.93). Oral intake was not predictive of hypotension in a multiple logistic regression model controlling for vintage, age, sex, BP medications, coronary disease, dialysis day and shift, diabetes mellitus, s‐Ca, Na and ultrafiltration profiles, and dialysis temperature, even when the analysis was restricted to runs where the patients reached the prescribed dry weight within 0.1 kg. The results of this study suggest that the mean OI during dialysis is just over 0.25 kg, with some patients consuming several kilograms. The clinical significance of OI is uncertain. We did not find an association between OI and hypotension. It is likely that this association was confounded by failure to achieve the prescribed dry weight in a proportion of patients with a high OI, as well as interventions implemented in response to hypotension in previous runs. For example, patients with previous episodes of low BP are advised to limit OI, are prescribed profiles, and so on. There may be other deleterious effects of high OI including hypertension and cardiac disease. The generalizability of the results of this largely Caucasian study population is a recognized limitation. Further prospective and blinded studies are needed to examine the association between OI and hypotension, the long‐term clinical consequences of OI, and to define thresholds for recommended OI during dialysis.
Transcriptional regulation of mouse mu opioid receptor gene in neuronal cells by Poly(ADP‐ribose) polymerase‐1
Authors: Choi Hack Sun , Hwang Cheol Kyu , Kim Chun Sung , Song Kyu Young , Law Ping‐Yee , Loh Horace H. , Wei Li‐Na
Published: February 2008

The pharmacological actions of morphine and morphine‐like drugs such as heroin mediate primarily through the mu opioid receptor (MOR). It represents the target of the most valuable painkiller in contemporary medicine. Here we report that poly(ADP‐ribose) polymerase 1 (PARP‐1) binds to the double‐stranded poly(C) element essential for the MOR promoter and represses promoter activity at the transcriptional level. We identified PARP‐1 by affinity column chromatography using the double‐stranded poly(C) element, followed by two‐dimensional gel electrophoresis and MALDI‐TOF mass spectrometry. PARP‐1 binding to the poly(C) sequence of the MOR gene was sequence‐specific as confirmed by the supershift assay. In cotransfection studies, PARP‐1 repressed the MOR promoter only when the poly(C) sequence was intact. When PARP‐1 was disrupted in NS20Y cells using siRNA, transcription of the endogenous target MOR gene increased significantly. Chromatin immunoprecipitation assays showed specific binding of PARP‐1 to the double‐stranded poly(C) element essential for the MOR promoter. Inhibition of PARP‐1's catalytic domain with 3‐aminobenzamide increased endogenous MOR mRNA levels in cultured NS20Y cells, suggesting that automodification of PARP‐1 regulates MOR transcription. Our data suggest that PARP‐1 can function as a repressor of MOR transcription dependent on the MOR poly(C) sequence. We demonstrate for the first time a role of PARP‐1 as a transcriptional repressor in MOR gene regulation.
Dominant‐negative mutation of monocyte chemoattractant protein‐1 prevents vulnerable plaques from rupture in rabbits independent of serum lipid levels
Authors: Zhong Lin , Chen Wen Qiang , Ji Xiao Ping , Zhang Mei , Zhao Yu Xia , Yao Gui Hua , Zhang Peng Fei , Zhang Cheng , Zhang Yun
Published: February 2008

Active inflammation is an important feature of vulnerable plaques, and monocyte chemoattractant protein‐1 (MCP‐1) is a key chemokine that promotes monocyte–endothelium binding and initiates inflammation. We aimed to determine whether dominant‐negative mutation of MCP‐1 could reverse atherosclerotic lesion progression and prevent vulnerable plaques from rupture regardless of serum lipid levels. The mutant MCP‐1 was produced by deletion of the N‐terminal amino acids 2 to 8 (7ND), and a eukaryotic expression vector plRES‐EGFP‐7ND was constructed. The transwell chamber was used to assay chemotaxis of monocytes in vitro. Thirty New Zealand white rabbits underwent balloon‐induced abdominal aortic endothelial injury and were randomly divided into control group without gene intervention (group A, n = 10), plRES‐EGFP‐7ND treatment group (group B, n = 10) and empty vector treatment group (group C, n = 10). All rabbits were fed a diet of 1% cholesterol for 8 weeks, and then group A rabbits were killed, whereas groups B and C rabbits received an intramuscular injection of plRES‐EGFP‐7ND and an empty lipofectamine, respectively, and remained on a high cholesterol diet for 4 weeks. At the end of week 12, groups B and C rabbits underwent pharmacological triggering by injection with Chinese Russellis viper venom and histamine. Serum lipids and inflammatory markers were measured, and high‐frequency ultra‐sonography and intravascular ultrasound imaging were performed. Immunohistochemistry and RT‐PCR were used to examine expression of inflammatory markers in the plaques. In vitro transfection of plRES‐EGFP‐7ND resulted in a significant inhibition of monocyte chemotaxis (P < 0.05) and in vivo transfection of plRES‐EGFP‐7ND significantly increased the thickness of the fibrous caps and decreased plaque vulnerability index. The incidence of plaque rupture in group B was 0% as compared with 56% in the empty vector treatment group (P< 0.05). The serum levels and expression of inflammatory markers were significantly reduced in group B. In conclusion, PIRES‐EGFP‐7ND transfection effectively inhibits plaque inflammation, reverses plaque progression and prevents vulnerable plaques from rupture. These therapeutic effects are independent of serum lipid levels and demonstrate that inhibition of plaque inflammation alone without lipid lowering can stabilize vulnerable plaques.
Validity and reliability of the Spanish versions of the Bech‐Rafaelsen’s mania and melancholia scales for bipolar disorders
Authors: Vieta E. , Bobes J. , Ballesteros J. , González‐Pinto A. , Luque A. , Ibarra N. ,   the Spanish Group for Psychometric Studies (GEEP)
Published: February 2008

Objective:  To assess classical psychometric properties of the Spanish versions of the Bech‐Rafaelsen’s mania (MAS) and melancholia (MES) scales.

Method:  Observational, prospective, and multicentric study in bipolar out‐patients. Convergent validity was assessed against the Young Mania Rating Scale and the Montgomery‐Åsberg Depression Rating Scale. Discriminant validity, reliability, and sensitivity to change, were also assessed.

Results:  One hundred and thirteen bipolar patients with a manic episode and 102 bipolar patients with a depressive episode were included. Both the MAS and the MES showed appropriate convergent validity (r > 0.90), discriminant validity (P < 0.0001), internal consistency (Cronbach’s alpha >0.80), test–retest reliability [intraclass correlation coefficient (ICC) = 0.69 for the MAS and 0.94 for the MES], inter‐rater reliability (ICC > 0.80), and sensitivity to change at 4 weeks since inception (P < 0.0001; within‐group effect size ≥1.8).

Conclusion:  The Spanish versions of both scales present appropriate psychometric estimates in bipolar patients treated in ambulatory care.
Long‐term suicide risk of depression in the Lundby cohort 1947–1997 – severity and gender
Authors: Brådvik L. , Mattisson C. , Bogren M. , Nettelbladt P.
Published: February 2008

Objective:  The long‐term suicide risk of depression was evaluated in a community sample by severity and gender.

Method:  The Lundby study is a prospective, longitudinal cohort study on a population consisting of 3563 subjects. In 1947–1997 medium or severe depression according to the Lundby diagnostic system were registered in 503 subjects. The same subjects were also diagnosed according to DSM‐IV showing major depressive disorder (MDD) in 293 and depressive disorder not otherwise specified (DDNOS) in 131 subjects.

Results:  The overall long‐term suicide risk varied from 5.6% to 6.8%. The long‐term suicide risk was 3.1% for medium and 11.4% for severe ‘Lundby depression’, 3.7% for medium and 13.8% for severe MDD + DDNOS, 3.1% for medium and 13.7% for severe MDD. Severity and male sex were risk factors for suicide.

Conclusion:  Males with a severe depression showed a high long‐term risk for suicide, around 20%.
Peri‐implant tissue response to TiO2 surface modified implants
Authors: Rossi Sami , Tirri Teemu , Paldan Hannu , Kuntsi‐Vaattovaara Helena , Tulamo Riitta , Närhi Timo
Published: February 2008

Objectives: The objective of this study was to evaluate peri‐implant soft tissue attachment and alveolar bone height on nanoporous TiO2 thin film on commercial titanium dental implants compared with unmodified standard implants.

Material and methods: In six adult beagle dogs, the mandibular premolars P2–P4 were extracted bilaterally. Sol–gel‐derived nanoporous TiO2 thin film was produced on smooth coronal part of standard ITI® Straumann implants (4.1 mm × 8.0 mm) by dip coating method. After 3 months healing period of the extraction sockets modified (n=24) and unmodified (n=11) control implants were placed bilaterally. The animals were killed after 8 weeks and the samples were retrieved and processed for histologic/histomorfometric and TEM/SEM evaluations.

Results: Histological examination showed mild or absent inflammatory reaction in peri‐implant connective tissues around the surface modified implants. Further, junctional epithelium (JE)/connective tissue (CT) appeared to be in immediate contact with the experimental implants. Of the experimental implants, 22% were judged to be detached from the implant surface while 45% of the untreated control implants were detached.

Dense plaques of hemidesmosomes were found in TEM evaluation of the JE cell membrane facing the surface‐treated implants. In the histomorfometric analysis, the distance between the implant margin and alveolar bone crest was significantly shorter in surface‐treated implants than in the control implants (P<0.02).

Conclusion: Nanoporous sol–gel‐derived TiO2 thin film on ITI® Straumann dental implants improved soft tissue attachment in vivo.
In vivo Trafficking and Localization of p24 Proteins in Plant Cells
Authors: Langhans Markus , Marcote María Jesús , Pimpl Peter , Virgili‐López Goretti , Robinson David G , Aniento Fernando
Published: February 2008

p24 proteins constitute a family of putative cargo receptors that traffic in the early secretory pathway. p24 proteins can be divided into four subfamilies (p23, p24, p25 and p26) by sequence homology. In contrast to mammals and yeast, most plant p24 proteins contain in their cytosolic C‐terminus both a dilysine motif in the −3, −4 position and a diaromatic motif in the −7, −8 position. We have previously shown that the cytosolic tail of Arabidopsis p24 proteins has the ability to interact with ARF1 and coatomer (through the dilysine motif) and with COPII subunits (through the diaromatic motif). Here, we establish the localization and trafficking properties of an Arabidopsis thaliana p24 protein (Atp24) and have investigated the contribution of the sorting motifs in its cytosolic tail to its in vivo localization. Atp24‐red fluorescent protein localizes exclusively to the endoplasmic reticulum (ER), in contrast with the localization of p24 proteins in other eukaryotes, and the dilysine motif is necessary and sufficient for ER localization. In contrast, Atp24 mutants lacking the dilysine motif are transported along the secretory pathway to the prevacuolar compartment and the vacuole, although a significant fraction is also found at the plasma membrane. Finally, we have found that ER export of Atp24 is COPII dependent, while its ER localization requires COPI function, presumably for efficient Golgi to ER recycling.
THE DIVERSITY–VALIDITY DILEMMA: OVERVIEW AND LEGAL CONTEXT
Authors: PYBURN KEITH M. , PLOYHART ROBERT E. , KRAVITZ DAVID A.
Published: February 2008

Due to racioethnic and sex subgroup differences on predictor scores in many selection procedures, it is difficult for organizations to simultaneously maximize the validity of their selection procedures and hire a diverse workforce. One response to this diversity–validity dilemma is to revise the selection procedures, an approach developed by Ployhart and Holtz (this issue, 2008). A second possible response is to use affirmative action to increase workforce diversity, an approach developed by Kravitz (this issue, 2008). This paper briefly presents the legal context that motivates and constrains these approaches. We begin by defining key terms, describing adverse impact, and outlining the burden of proof in adverse impact cases. We then turn to the use of racioethnic minority and female preferences, summarizing some key court decisions and the conditions under which private and public employers may use preferences.
Antiviral and Anticancer Optimization Studies of the DNA‐binding Marine Natural Product Aaptamine
Authors: Bowling John J. , Pennaka Hari K. , Ivey Kelly , Wahyuono Subagus , Kelly Michelle , Schinazi Raymond F. , Valeriote Frederick A. , Graves David E. , Hamann Mark T.
Published: February 2008

Aaptamine has potent cytotoxicity that may be explained by its ability to intercalate DNA. Aaptamine was evaluated for its ability to bind to DNA to validate DNA binding as the primary mechanism of cytotoxicity. Based on UV–vis absorbance titration data, the Kobs for aaptamine was 4.0 (±0.2) × 103 which was essentially equivalent to the known DNA intercalator N‐[2‐(diethylamino)ethyl]‐9‐aminoacridine‐4‐carboxamide. Semi‐synthetic core modifications were performed to improve the general structural diversity of known aaptamine analogs and vary its absorption characteristics. Overall, 26 aaptamine derivatives were synthesized which consisted of a simple homologous range of mono and di‐N‐alkylations as well as some 9‐O‐sulfonylation and bis‐O‐isoaaptamine dimer products. Each product was evaluated for activity in a variety of whole cell and viral assays including a unique solid tumor disk diffusion assay. Details of aaptamine’s DNA‐binding activity and its derivatives’ whole cell and viral assay results are discussed.
Role of Na+,K+‐pumps and transmembrane Na+,K+‐distribution in muscle function
Authors: Clausen T.
Published: February 2008

Na+,K+‐ATPase situated in the plasma membrane mediates active extrusion of Na+ and intracellular accumulation of K+. This transport system – the Na+,K+‐pump – is the major regulator of the transmembrane distribution of Na+ and K+, and is itself subject to regulation by a wide variety of factors in skeletal muscles.

The excitation of skeletal muscles is elicited by a rapid influx of Na+, followed by an equivalent efflux of K+ across sarcolemmal and t‐tubular membranes. Due to their size and sudden onset, these events constitute the major transport challenge for the Na+,K+‐pumps. Skeletal muscles contain the largest single pool of K+ in the organism. During intense exercise, the Na+,K+‐pumps cannot readily reaccumulate K+ into the muscle cells. Therefore, the working muscles undergo a net loss of K+, causing up to a doubling of the K+ concentration in the arterial blood plasma in less than 1 min and even larger increases in interstitial K+. This may induce depolarization, loss of excitability and force, in particular in muscles, where the excitation‐induced passive Na+,K+‐fluxes are large. During continuous stimulation of isolated rat muscles, there is a highly significant correlation between the rise in extracellular K+ and the rate of force decline. Fortunately, excitation increases the Na+,K+‐pumping rate within seconds. Thus, maximum activation of up to 20‐fold above the resting transport rate may be reached in 10 s, with utilization of all available Na+,K+‐pumps. In muscles, where excitability is reduced by pre‐exposure to high [K+]o, acute activation of the Na+,K+‐pumps by hormones or intermittent electrical stimulation restores excitability and contractility. In working muscles, the Na+,K+‐pumps, due to rapid activation of their large transport capacity, play a dynamic regulatory role in the from second to second ongoing restoration and maintenance of excitability and force. Excitation is a self‐limiting process that depends on the leak/pump ratio for Na+ and K+. Acute inhibition of the Na+,K+‐pumps with ouabain or downregulation of the Na+,K+‐pump capacity clearly reduces contractile endurance in isolated muscles. The Na+,K+‐pumps are a limiting factor for contractile force and endurance. This is in particular noted if their capacity is reduced because of inactivity or disease. For these reasons, tight regulation of the Na+,K+‐pumps is crucial for the maintenance of plasma K+, membrane potential and excitability in skeletal muscle. This is achieved by:

acute activation of the Na+,K+‐pumps elicited by excitation, catecholamines, insulin, insulin‐like growth factor I, calcitonins and amylin; and

long‐term regulation of the content of Na+,K+‐pumps exerted by thyroid hormones, adrenal steroids, insulin, training, inactivity, fasting, K+‐deficiency or K+‐overload.

In conclusion, the Na+,K+‐pump is a central target for regulation of Na+,K+‐distribution, important for the contractile performance of skeletal muscles, the pathophysiology of several diseases and for therapeutic intervention.
Plasticizer Types and Coating Methods Affect Quality and Shelf Life of Eggs Coated with Chitosan
Authors: Kim S.H. , No H.K. , Prinyawiwatkul W.
Published: February 2008

ABSTRACT:  Effects of different plasticizer types (glycerol, propylene glycol, and sorbitol) and coating methods (brushing, dipping, and spraying) on the internal quality and shelf life of chitosan‐coated eggs were evaluated during 5 wk of storage at 25 °C. The Haugh unit and yolk index values suggested that chitosan coating, irrespective of the plasticizer types, extended the shelf life of eggs by almost 3 wk at 25 °C compared with noncoated eggs. After 5 wk of storage, plasticizer types did not significantly affect the quality (weight loss, Haugh unit, and yolk index) of chitosan‐coated eggs. However, there was an observable trend indicating that use of sorbitol rather than propylene glycol and glycerol as a plasticizer was better in reducing weight loss (whole egg) of chitosan‐coated eggs during a 5‐wk storage. After a 5‐wk storage, there were no significant differences in weight loss and weight of albumen and yolk among chitosan‐coated eggs, regardless of the coating methods. However, both brushing and dipping methods yielded chitosan‐coated eggs with better yolk (higher yolk index values) and albumen (lower pH) qualities than did the spraying method. During 3 to 5 wk of storage, the Haugh unit values of chitosan‐coated eggs by the brushing method were higher than or comparable to those by dipping or spraying. Therefore, coating of eggs with chitosan using sorbitol as a plasticizer and by the brushing method may offer a protective barrier in preserving the internal quality and thus extending shelf life of eggs.