bluuebunny/crossref_metadata_2025 huggingface dataset:
Creativity and Narrative Task Performance: An Exploratory Study
Authors: Albert Ágnes , Kormos Judit
Published: May 2011

Methods of communicative and task‐based language teaching often employ tasks that require students to use their imagination and to generate new ideas. These tasks might provide creative learners with more chance to practice and to produce more comprehensible output, which could lead to greater success in second language acquisition (SLA) (Swain, 1985). Therefore, creativity, which involves imagination, unconventionality, risk‐taking, flexibility, and creating new classifications and systematizations of knowledge (Sternberg, 1985a), might be a potential factor that affects language learning outcomes. Despite its potential relevance, creativity has been a neglected individual difference variable in the field of SLA. Our study is the first attempt to examine the role of creativity in second‐language oral task performance. Participants in the study were Hungarian secondary school learners of English whose creativity was measured with a standardized creativity test and who performed two versions of a narrative task. We examined the relationships among three aspects of creativity—originality, flexibility, and creative fluency—and different measures of task performance, which included the number of words and narrative clauses, subordination ratio, lexical variety, and accuracy. The findings suggest that creativity is best hypothesized as a multifaceted trait, as students scoring high on various components of creativity seemed to complete the same task in different ways. Students who invented a high number of solutions on a creativity test were found to engage in more talk; thus, in a foreign language setting, they might create more opportunities for themselves to use the language. The learners characterized by a higher level of originality tended to speak less and created more complex stories in terms of the narrative structure, but at the same time, they might deprive themselves of the beneficial effects of more output. No significant relationship among creativity and accuracy, complexity, and lexical variety was found. The magnitude of the correlations, however, indicates that creativity affects participants’ output in narrative tasks only moderately. The results of the study reveal that in addition to investigating the effects of individual variables on global measures of foreign language performance, it is also possible to study their influence on specific tasks. Based on our study, we conclude that different aspects of creativity might have an effect on the amount of output students produce but not on the quality of narrative performance. Nevertheless, further research involving more participants and using different types of tasks would be necessary to be able to generalize these findings to other contexts.
North‐South Migration in Ghana: What Role for the Environment?
Authors: van der Geest Kees
Published: May 2011

The purpose of this paper is to determine the importance of the environment as a driver of North‐South migration in Ghana. Almost one in every five people born in northern Ghana is living in southern Ghana. Interviews with 203 migrant farmers suggest that migration from the North to the South is, to a large extent, environmentally induced. Many Northerners decided to migrate because of poor agro‐ecological conditions at home combined with easy access to fertile lands in the more humid destination area. The interviews with migrant farmers yielded several insights that are relevant for the environmental refugee debate. Firstly, environmental pull appears to be at least as important as environmental push. Secondly, scarcity of fertile land was mentioned much more often as a reason to migrate than climate change or erratic rainfall. Thirdly, none of the respondents ascribed the migration decision to sudden‐onset environmental stress. If the environment is indeed an important driver of migration, one would expect migration rates to be higher in places with and times of more severe scarcity. A cross‐sectional analysis of migration propensities and natural resources scarcity confirms that out‐migration rates are significantly higher in poorly endowed districts. A longitudinal analysis of migration and rainfall shows that the period of worst environmental stress ‐‐ during the Sahelian droughts of the late 1970s and early 1980s ‐‐ was a time of reduced out‐migration from northern Ghana. In this period of northern Ghana’s migration history, economic and political factors weighed heavier than environmental factors. The picture that emerges for northern Ghana is not one of distress migration in the face of environmental disaster but rather of migration as a way of dealing with structural environmental scarcity.
Environmental Degradation and Migration on Hispaniola Island
Authors: Alscher Stefan
Published: May 2011

Sharing the same island, the Dominican Republic and Haiti are confronting similar environmental challenges. Located on the path of tropical storms, Hispaniola Island is frequently exposed to natural disasters like heavy rainfall, flooding and landslides, aggravated by human‐induced environmental degradation. At the same time, the differences between the two nations are extreme. Haiti is the poorest country in the Western Hemisphere and a well‐known case in environmental studies as nearly all of its forests have disappeared. In the Dominican Republic, a middle‐income country known for its beaches and tourist resorts, deforestation and soil erosion is also a problem, but to a much lower extent compared to its neighbour state. Above all, the rural economy in both countries is suffering from both sudden disasters and slow‐onset environmental degradation. Together with the lack or withdrawal of state support, the incentives for migration as an adaptation strategy are increasing in this panorama of environmental degradation and economic losses. On the basis of field research in selected regions of both countries, this paper analyses the impacts of environmental change on internal and international migration flows on Hispaniola Island.
Flooding and Relocation: The Zambezi River Valley in Mozambique
Authors: Stal Marc
Published: May 2011

Since the 1980’s there has been an increasing debate throughout the world, that argues whether environmental degradation is a major cause of migration. Scientists claimed there were millions of “environmental refugees” in the late 1980s. The discussion of the links between environmental change and migration have since then been widely debated, especially because of the lack of empirical data on the linkages of the environment and migration. Within the last years the Nobel price winning International Panel on Climate Change (IPCC, 2007) raised awareness about future impacts of climate change and stated that extreme weather events will occur more frequently and the number of people affected will be highest in the low‐lying deltas of Asia and Africa.

Heavy rain in south eastern Africa in early 2008 flooded the low‐lying river areas along the Zambezi River in Central Mozambique and displaced up to 80,000 people ‐‐ the second such occurrence within two years. This number adds to tens of thousands of people already displaced from floods and cyclones during 2000, 2001 and 2007. Flooding in Mozambique provides a picture of the vulnerability many developing countries experience vis‐à‐vis extreme climate events. Resettlement has become a policy of last resort for a government trying to ensure safety in a populated area. Mozambique has in recent years become a prominent example of environmentally induced displacement/migration caused by flooding, and the efforts of a government to balance the safety of threatened people with the need to earn livelihoods on floodplains. Hence, this paper aims to understand the impacts of current extreme weather events, especially for a region of the world where the population is surviving via subsistence economy. This paper intends to decrease the lack of data on the linkages between the environment, displacement and migration and identify the major issues in dealing with these impacts.
Protective effect of the octadecaneuropeptide on hydrogen peroxide‐induced oxidative stress and cell death in cultured rat astrocytes
Authors: Hamdi Yosra , Masmoudi‐Kouki Olfa , Kaddour Hadhemi , Belhadj Feten , Gandolfo Pierrick , Vaudry David , Mokni Meherzia , Leprince Jérôme , Hachem Raya , Vaudry Hubert , Tonon Marie‐Christine , Amri Mohamed
Published: May 2011

J. Neurochem. (2011) 118, 416–428.

Oxidative stress, resulting from accumulation of reactive oxygen species (ROS), plays a critical role on astrocyte death associated with neurodegenerative diseases. Astroglial cells produce endozepines, a family of biologically active peptides that have been implicated in cell protection. Thus, the purpose of the present study was to investigate the potential protective effect of one of the endozepines, the octadecaneuropeptide ODN, on hydrogen peroxide (H2O2)‐induced oxidative stress and cell death in rat astrocytes. Incubation of cultured astrocytes with graded concentrations of H2O2 for 1 h provoked a dose‐dependent reduction of the number of living cells as evaluated by lactate dehydrogenase assay. The cytotoxic effect of H2O2 was associated with morphological modifications that were characteristic of apoptotic cell death. H2O2‐treated cells exhibited high level of ROS associated with a reduction of both superoxide dismutases (SOD) and catalase activities. Pre‐treatment of astrocytes with low concentrations of ODN dose‐dependently prevented cell death induced by H2O2. This effect was accompanied by a marked attenuation of ROS accumulation, reduction of mitochondrial membrane potential and activation of caspase 3 activity. ODN stimulated SOD and catalase activities in a concentration‐dependent manner, and blocked H2O2‐evoked inhibition of SOD and catalase activities. Blockers of SOD and catalase suppressed the effect of ODN on cell survival. Taken together, these data demonstrate for the first time that ODN is a potent protective agent that prevents oxidative stress‐induced apoptotic cell death.
Value, gleaning and the archive at Maxwell Street, Chicago
Authors: Cresswell Tim
Published: May 2011

This paper explores the process of creating archives through an exploration of a range of archival sites in Chicago, Illinois. These sites contain objects believed to be of value that were once located in or referred to the area of the Maxwell Street Market, once the largest open air market in North America. The paper contributes to discussions of the geography of archives and archiving on the one hand, and the processes of evaluation that give objects value on the other. It does so by examining how different objects are given contrasting and competing values by different people in different places. These places include the formal archives, the place itself, a collection of objects stored for a possible museum in the future and a private residence in the city. Following an introduction to the area and a discussion of the nature of archives, three sets of gleaners are examined: journalists and photographers whose accounts and images can be found in the Chicago History Museum, the members of the Maxwell Street Historic Preservation Coalition and the Maxwell Street enthusiast and activist, Steve Balkin. The conclusion considers the different ways in which objects are valued in these different archives and demonstrates how archives are leaky places produced through a contested set of valuations concerning which objects count as worthy and significant.
In Vivo Evaluation of the “TinyPump” as a Pediatric Left Ventricular Assist Device
Authors: Kitao Takashi , Ando Yusuke , Yoshikawa Masaharu , Kobayashi Mariko , Kimura Taro , Ohsawa Hideyuki , Machida Shinya , Yokoyama Naoyuki , Sakota Daisuke , Konno Tomohiro , Ishihara Kazuhiko , Takatani Setsuo
Published: May 2011

Pediatric patients with end‐stage heart failure require mechanical circulatory support (MCS) just as adults do. In order to meet the special requirements for neonates' and infants' MCS, pediatric circulatory support devices must be compact with low priming volume, easily controllable with low flow, less traumatic for blood cells and tissues, and biocompatible with minimum anticoagulation. We have designed and developed a miniature rotary centrifugal blood pump, “TinyPump,” with a priming volume of 5 mL, which has already demonstrated its controllable performance for low flow and durability in vitro. To evaluate the feasibility of the TinyPump as a left ventricular assist device (LVAD) suitable for neonates and infants, we have examined the biocompatibility and hemodynamic performance of the TinyPump in a pediatric animal model using Shiba goats. The TinyPump is a miniaturized centrifugal pump weighing 150 g comprising a disposable pump head with a 30‐mm diameter impeller having six straight‐vanes and a reusable motor driver. The impeller in the pump head is supported by a hydrodynamic bearing at its center and is driven by radial magnetic force coupled to the motor driver. TinyPump implantations were performed in 22 Shiba goats (17 female and 5 male), with body weights ranging from 8.4 to 27.2 kg. Under gas anesthesia, via left lateral thoracotomy, a 22 Fr inflow cannula was inserted through the left ventricular apex, while a 6‐mm outflow graft was anastomosed to the descending aorta, which were then connected to a TinyPump mounted on the animal's back. Postoperative hemodynamic monitoring included heart rate, arterial and central venous pressure, pump flow, and rotation speed. Target pump flow in all animals was maintained at 0.9 ± 0.1 L/min, which is approximately half the normal pulmonary artery flow measured in control animals. Blood samples were collected to evaluate peripheral organ functions, hemolysis, and thrombosis. Goats were divided into three groups—acute phase (6 h; n = 4), subchronic phase (6 h 2 postoperative days [POD]; n = 11), and chronic phase (3 POD–16 POD; n = 8)—based on their survival duration. In the early experiments, hemolysis and thrombi formation at the impeller bearing resulted in termination of the study. Subsequent modifications of the bearing design, pump housing design, and magnetic coupling force helped to minimize the hemolysis and thrombi formation, prolonging the survival duration of the Shiba goats to 2 weeks with minimum adverse effects on the blood components and organ functions. With further experiments and improvements in pump durability and hemocompatibility, the TinyPump can serve as a suitable circulatory support device for neonates and infants bridging to heart transplantation as well as to heart recovery.
Delivery of the Bioactive Gas Hydrogen Sulfide During Cold Preservation of Rat Liver: Effects on Hepatic Function in an Ex vivo Model
Authors: Balaban Cecilia L. , Rodriguez Joaquín V. , Guibert Edgardo E.
Published: May 2011

The insults sustained by transplanted livers (hepatectomy, hypothermic preservation, and normothermic reperfusion) could compromise hepatic function. Hydrogen sulfide (H2S) is a physiologic gaseous signaling molecule, like nitric oxide (NO) and carbon monoxide (CO). We examined the effect of diallyl disulfide as a H2S donor during hypothermic preservation and reperfusion on intrahepatic resistance (IVR), lactate dehydrogenase (LDH) release, bile production, oxygen consumption, bromosulfophthalein (BSP) depuration and histology in an isolated perfused rat liver model (IPRL), after 48 h of hypothermic storage (4°C) in University of Wisconsin solution (UW, Viaspan). Livers were retrieved from male Wistar rats. Three experimental groups were analyzed: Control group (CON): IPRL was performed after surgery; UW: IPRL was performed in livers preserved (48 h—4°C) in UW; and UWS: IPRL was performed in livers preserved (48 h—4°C) in UW in the presence of 3.4 mM diallyl disulfide. Hypothermic preservation injuries were manifested at reperfusion by a slight increment in IHR and LDH release compared with the control group. Also, bile production for the control group (1.32 µL/min/g of liver) seemed to be diminished after preservation by 73% in UW and 69% in UW H2S group at the end of normothermic reperfusion. Liver samples analyzed by hematoxylin/eosin clearly showed the deleterious effect of cold storage process, partially reversed (dilated sinusoids and vacuolization attenuation) by the addition of a H2S delivery compound to the preservation solution. Hepatic clearance (HC) of BSP was affected by cold storage of livers, but there were no noticeable differences between livers preserved with or without diallyl disulfide. Meanwhile, livers preserved in the presence of H2S donor showed an enhanced capacity for BSP uptake (kACON = 0.29 min−1; kAUW = 0.29 min−1; kAUWS = 0.36 min−1). In summary, our animal model suggests that hepatic hypothermic preservation for transplantation affects liver function and hepatic depuration of BSP, and implies that the inclusion of an H2S donor during hypothermic preservation could improve standard methods of preparing livers for transplant.
Dendronized Polyaniline Nanotubes for Cardiac Tissue Engineering
Authors: Moura Renata Mendes , de Queiroz Alvaro Antonio Alencar
Published: May 2011

Today, nanobiomaterials represent a very important class of biomaterials because they differ dramatically in their bulk precursors. The properties of these materials are determined by the size and morphology, thus creating a fascinating line in their physicochemical properties. Polyaniline nanotubes (PANINTs) are one of the most promising nanobiomaterials for cardiac tissue engineering applications due to their electroactive properties. The biocompatibility and low hydrophilic properties of PANINTs can be improved by their functionalization with the highly hydrophilic polyglycerol dendrimers (PGLDs). Hydrophilicity plays a fundamental role in tissue regeneration and fundamental forces that govern the process of cell adhesion and proliferation. In this work, the biocompatible properties and cardiomyocyte proliferation onto PANINTs modified by PGLD are described. PGLDs were immobilized onto PANINTs via surface‐initiated anionic ring‐opening polymerization of glycidol. The microstructure and morphology of PGLD‐PANINTs was determined by X‐ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), respectively. The cardiac cell growth on the PGLD‐PANINTs was investigated. The PGLD‐coated PANINTs showed noncytotoxic effects to Chinese hamster ovary cells. It was observed that the application of microcurrent stimulates the differentiation of cardiac cells cultured on PGLD‐PANINTs scaffolds. The electroactive and biocompatible results of PGLD‐PANINTs observed in this work demonstrate the potential of this nanobiomaterial for the culture of cardiac cells and open the possibility of using this material as a biocompatible electroactive three‐dimensional matrix in cardiac tissue engineering.
Implantable Centrifugal Blood Pump With Dual Impeller and Double Pivot Bearing System: Electromechanical Actuator, Prototyping, and Anatomical Studies
Authors: Bock Eduardo , Antunes Pedro , Leao Tarcisio , Uebelhart Beatriz , Fonseca Jeison , Leme Juliana , Utiyama Bruno , da Silva Cibele , Cavalheiro Andre , Filho Diolino Santos , Dinkhuysen Jarbas , Biscegli Jose , Andrade Aron , Arruda Celso
Published: May 2011

An implantable centrifugal blood pump has been developed with original features for a left ventricular assist device. This pump is part of a multicenter and international study with the objective to offer simple, affordable, and reliable devices to developing countries. Previous computational fluid dynamics investigations and wear evaluation in bearing system were performed followed by prototyping and in vitro tests. In addition, previous blood tests for assessment of normalized index of hemolysis show results of 0.0054 ± 2.46 × 10−3 mg/100 L. An electromechanical actuator was tested in order to define the best motor topology and controller configuration. Three different topologies of brushless direct current motor (BLDCM) were analyzed. An electronic driver was tested in different situations, and the BLDCM had its mechanical properties tested in a dynamometer. Prior to evaluation of performance during in vivo animal studies, anatomical studies were necessary to achieve the best configuration and cannulation for left ventricular assistance. The results were considered satisfactory, and the next step is to test the performance of the device in vivo.
Preparation and Characterization of an Acellular Bovine Pericardium Intended for Manufacture of Valve Bioprostheses
Authors: Goissis Gilberto , de Fátima Giglioti Aparecida , Braile Domingo Marcolino
Published: May 2011

Major problems with biological heart valves post‐implantation are associated with progressive structural deterioration and calcification attributed to glutaraldehyde processing, dead cells, and cell fragments present in the native tissue. In spite of these problems, glutaraldehyde still is the reagent of choice. The results with acellular matrix xenograft usually prepared by detergent treatment in association with enzymes are rather conflicting because while preserving mechanical properties, tissue morphology and collagen structure are process dependent. This work describes a chemical approach for the preparation of an acellular bovine pericardium matrix intended for the manufacture of heart valve bioprostheses. Cell removal was performed by an alkaline extraction in the presence of calcium salts for periods ranging from 6 to 48 h. The results showed that cell removal was achieved after 12 h, with swelling and negative charge increasing with processing time. Nevertheless, collagen fibril structure, ability to form fibrils, and stability to collagenase were progressive after 24‐h processing. There was no denaturation of the collagen matrix. A process is described for the preparation of acellular bovine pericardium matrices with preserved fibril structure and morphology for the manufacture of cardiac valve bioprostheses and may be used in other applications for tissue reconstruction.
Cardiovascular Simulator Improvement: Pressure Versus Volume Loop Assessment
Authors: Fonseca Jeison , Andrade Aron , Nicolosi Denys E.C. , Biscegli José F. , Leme Juliana , Legendre Daniel , Bock Eduardo , Lucchi Julio Cesar
Published: May 2011

This article presents improvement on a physical cardiovascular simulator (PCS) system. Intraventricular pressure versus intraventricular volume (PxV) loop was obtained to evaluate performance of a pulsatile chamber mimicking the human left ventricle. PxV loop shows heart contractility and is normally used to evaluate heart performance. In many heart diseases, the stroke volume decreases because of low heart contractility. This pathological situation must be simulated by the PCS in order to evaluate the assistance provided by a ventricular assist device (VAD). The PCS system is automatically controlled by a computer and is an auxiliary tool for VAD control strategies development. This PCS system is according to a Windkessel model where lumped parameters are used for cardiovascular system analysis. Peripheral resistance, arteries compliance, and fluid inertance are simulated. The simulator has an actuator with a roller screw and brushless direct current motor, and the stroke volume is regulated by the actuator displacement. Internal pressure and volume measurements are monitored to obtain the PxV loop. Left chamber internal pressure is directly obtained by pressure transducer; however, internal volume has been obtained indirectly by using a linear variable differential transformer, which senses the diaphragm displacement. Correlations between the internal volume and diaphragm position are made. LabVIEW integrates these signals and shows the pressure versus internal volume loop. The results that have been obtained from the PCS system show PxV loops at different ventricle elastances, making possible the simulation of pathological situations. A preliminary test with a pulsatile VAD attached to PCS system was made.
In vivo neutralization of anti‐A and successful transfusion of A antigen–incompatible red blood cells in an animal model
Authors: Oliver Caroline , Blake Deborah , Henry Stephen
Published: May 2011

BACKGROUND: Our aim was to determine if the historical principle of Lewis glycolipid neutralization of antibody and subsequent Lewis‐incompatible transfusion could be extended and applied to the ABO blood group system using synthetic glycolipid‐like constructs.

STUDY DESIGN AND METHODS: In vitro experiments with human blood and blood group A function‐spacer‐lipid constructs (FSL‐A) were used to determine rates and concentrations that caused antigen transformation and anti‐A neutralization. FSL‐A constructs were intravenously infused into naive and anti‐A–immunized mice to determine in vivo antigen transformation, anti‐A inhibition, and tolerance to A antigen–incompatible transfusions (A+biotin kodecytes).

RESULTS: FSL‐A was able to cause in vivo transformation of circulating mouse cells into A antigen–positive cells (in vivo A kodecytes) without consequence in animals either with or without circulating anti‐A. FSL‐A was able to neutralize circulating anti‐A and allow for successful transfusion of incompatible A kodecytes. In the absence of FSL‐A neutralization incompatible cells were rapidly destroyed.

CONCLUSIONS: FSL constructs have the potential to neutralize circulating antibodies and allow for, or mitigate, the consequences of ABO‐incompatible red blood cell transfusion.
The Participation Paradox of Indigenous Autonomy in Mexico
Authors: Hiskey Jonathan T. , Goodman Gary L.
Published: May 2011

As indigenous movements around the world seek to strengthen their collective voice in their respective political systems, efforts continue to design political institutions that offer both sufficient local autonomy and incentives to participate in the broader political system. The state of Oaxaca, Mexico, offers a test case of one such effort at indigenous-based institutional design. This article argues that such reforms often fail to confront the tension between local autonomy and citizen engagement in politics outside the borders of the community. Testing this theory through a comparative analysis of voter turnout rates in municipalities across the state of Oaxaca and the neighboring state of Guerrero, this study finds that the adoption of indigenous institutions at the local level is associated with significantly lower voter turnout rates for national elections.
A geographic comparison of pseudogamous populations of the fall cankerworm (Alsophila pometaria)
Authors: Mitter C. , Neal J. W. , Gott K. M. , Silverfine E.
Published: May 2011

Phenological and genetic observations were made during two outbreak seasons on a population of the fall cankerworm, Alsophila pometaria Harris (Lepidoptera, Geometridae), at Beltsville, Maryland, U.S.A. As in intensively‐studied populations 300 km to the northeast on Long Island, New York, this population consisted mostly of asexual females requiring conspecific mating to reproduce. The estimated fraction of outcrossing (15–20%), however, was several times that typical for Long Island. Numerous intersexes were found, concentrated in a few families, suggesting that pseudogamy is controlled by more than one heritable factor. The genetic diversity and ecological heterogeneity among asexual females in the Maryland population appear similar to that on Long Island, but there is little overlap in common asexual genotypes. Electromorph frequencies at three loci in males, by contrast, show little geographic variation. The adult activity period is later and longer in Maryland than in colder parts of the range.

Comparaison de population géographiques d'Alsophila pometaria

Au cours d'une pullulation d'Alsophila pometaria, à Beltsville, Maryland, U.S.A., nous avons contrǒlé les émergences des papillons pendant deux saisons, échantillonné les sexes et les génotypes par électrophorèse pour quatre loci, puis nous avons examiné l'héritabilité de ces marqueurs électropho‐rétiques dans la descendance élevée au laboratoire. Comme pour les populations étudiées avec précision à 300 km au N.E à Long Island, New York, cette population comprenait essentiellement des femelles asexuées exigeant des accouplements conspécifiques pour se reproduire. Environ 15% de la descendance examinée présentait une ségrégation, contre 5% ou moins à Long Island. De nombreux intersexués élevés à partir des populations de Maryland et de New York, se trouvaient uniquement dans quelques lignées, ceci suggère que le rejet des spermatozoïdes et la diploïde des oeufs qui caractérise la pseudogamie, ont des déterminismes génétiques séparés. La diversité des femelles asexuées de la population de Beltsville, dominée par quatre génotypes asexués, paraǐt semblable à celle de Long Island, mais les clones similaires se chevauchent très peu. Par contre, les fréquences allèliques de tois loci sont presque identiques chez les mǎles de deux localités. Les fréquences génétiques des chenilles diffèrent pour des échantillons prélevés à quelques kilomètres de distance sur des hǒtes différents dans la měme population; il en est de měme pour des femelles prélevées a différentes époques. Tout ceci suggère une hétérogénéité écologique parmi les clones, comme cela a été suggéré pour Long Island. La période d'activité des adultes est plus tardive, plus marquée et plus longue au Maryland que dans les parties les plus froides de l'aire; elle s'étend de décembre à mars, avec les captures les plus fortes en janvier et février.
Metabolic costs of mixed‐function oxidase induction in Heliothis zea
Authors: Neal J. J.
Published: May 2011

The maximum metabolic cost of microsomal mixed‐function oxidase (MFO) induction was measured in terms of food utilization parameters. MFOs in larvae of Heliothis zea (Boddie) (Lepidoptera: Noctuidae) were induced by feeding on diet containing indole 3‐carbinol (I3C). Growth, food utilization parameters, cytochrome P‐450 content and O‐demethylase activity of these larvae were compared to larvae reared on the same diet without I3C. Three‐fold to nine‐fold greater O‐demethylase activity and seven‐fold more cytochrome P‐450 were measured in larvae fed I3C, but no differences were detected in the food utilization and growth parameters. These results do not support the view that costs of MFO induction may be responsible for differences in food utilization parameters.

Coǔts métaboliques de l'induction de la fonction oxydase mixte chez Heliothis zea

Le coǔt métabolique maximum de l'induction de la fonction oxydase mixte microsomale (MFO) a été évalué au moyen de paramètres caractérisant l'utilisation de l'aliment. Les MFO des chenilles d'H. zea ont été induites en les élevant avec un régime contenant 0,2 % d'indole 3‐carbinol (I3C) en poids/poids humide. L'induction a été mise en évidence en mesurant l'O‐deméthylation du p‐nitroanisole par les microsomes de l'intestin des larves des 4ème et 5ème stades, et la teneur en cytochrome P‐450 (mesurée par les différences des spectres de l'oxyde de carbone) des microsomes de l'intestin des larves du 5ème stade élevées avec I3C et témoins. La digestibilité approchée, l'efficacité de la conversion de l'aliment digéré et l'efficacité de la conversion de l'aliment ingéré (évaluée d'après la durée de développement larvaire de la néonate à la prénymphe), le temps pour atteindre le stade prénymphe, le poids final, on été comparés chez les témoins et chez les chenilles élevées sur I3C. Les chenilles élevées sur I3C ont présenté une activité O‐deméthylase 3 à 2 fois supérieure et 7 fois plus de cytochrome P‐450, mais aucune différence n'a pu ětre décelée pour les paramètres d'utilisation alimentaire et de croissance. Ces résultats ne confirment pas l'hypothèse suivant laquelle le coǔt de l'induction de MFO pourraǐt ětre responsable de différences dans les paramètres de l'utilisation de l'aliment.
Self and conspecific superparasitism by the egg parasitoid Trichogramma evanescens
Authors: van Dijken Marianne J. , Waage Jeffrey K.
Published: May 2011

Superparasitism is a widespread phenomenon in insect parasitoids and may be advantageous in certain circumstances. In this paper, we distinguish two kinds of superparasitism with different adaptive consequences for an ovipositing parasitoid: self superparasitism, where a parasitoid oviposits in a host in which she has previously oviposited, and conspecific superparasitism, where she oviposits in a host containing egg(s) from a previous oviposition by a conspecific. Our studies on Trichogramma evanescens Westwood show that females lay smaller clutches on parasitized than on healthy hosts but make the same overall allocation of males and females, although the sequence of sexes during oviposition differs. No difference was found between allocation in self and conspecific superparasitism. These results are discussed in the light of theories for progeny and sex allocation.

Selbst‐ und Konspezifisch‐Superparasitismus durch die Schlupfwespe Trichogramma evanescens

Superparasitismus ist ein weitverbreitetes Phänomen in Parasitoiden von Insekten und es kann unter bestimmten Umständen vorteilhaft sein. Diese Arbeit macht Unterschied zwischen zwei Formen von Superparasitismus, jeder mit seiner eigenen adaptiven Konsequenz für die parasitierende Schlupfwespe: Selbst‐Superparasitismus, wenn eine Schlupfwespe einen Wirt parasitiert die sie vorher selbst parasitiert hat, und Konspezifisch‐Superparasitismus, wenn sie einen Wirt parasitiert die vorher von einem Artgenossen parasitiert worden ist. Unsere Untersuchungen an Trichogramma evanescens zeigen dass die Weibchen auf den belegten Wirten kleinere Gelege haben als auf den gesunden Wirten, aber das Gesamtverhältnis von männlichen und weiblichen Brut ist dasselbe, obschon die Reihenfolge in den die Eier der beiden Geschlechte abgelegt werden sich underscheiden. Keinen Unterschied wurde gefunden zwischen die Ablegung während Selbst‐Superparasitismus und Konspezifisch‐Superparasitismus. Diese Ergebnisse werden diskutiert im Rahmen der Theorien für die Belegung des Wirtes in bezug auf die Anzahl und das Geschlecht der Eier.
Egg‐laying strategy under natural conditions of Leptopilina boulardi, a hymenopteran parasitoid of Drosophila spp
Authors: Carton Y. , Chibani F. , Haouas S. , Marrakchi M.
Published: May 2011

The hypothesis of optimal host species selection predicts that when a parasitoid has the choice between two host species, it will choose the species that gives the best survival chances for its progeny. We confirmed this hypothesis by laboratory experiments with Leptopilina boulardi Barb. et al., a cynipid parasitoid which prefers Drosophila melanogaster Meigen (the host species most suitable for parasitoid survival) above D. simulans Sturt. As far as fitness parameters are concerned, the fertility of L. boulardi is higher with D. melanogaster, the egg laying can be spread out over a long period when this host is relatively scarce. This does not occur with D. simulans in which parasitic oviposition stops soon when this host is not abundant.

Investigations of this foraging strategy were done under more complex natural conditions. We found that L. boulardi has a type III functional response with D. melanogaster only; furthermore, it seems that a switching effect may exist with this host. Parasitoid females appear to distribute their eggs more regularly on D. melanogaster, thus avoiding superparasitism. This seems to be independent of the relative frequency of this host. However, superparasitism of D. simulans did occur more frequently when this host was scarce.

Stratégie de ponte de Leptopilina boulardi (Hyménoptère parasite de drosophiles) dans les conditions naturelles

Le concept de réponse optimale d'un parasite vis‐à‐vis de l'hǒte le plus favorable pour son développement demeure surtout théorique et n'a pu ětre vérifié que dans les conditions de laboratoire. Nous avons montré que Drosophila melanogaster s'avère ětre, par rapport à D. simulans, l'hǒte le plus favorable pour le développement du cynipide parasite Leptopilina boulardi. Une étude sur le terrain a démontré que ce parasite présente une réponse fonctionnelle densité dépendante vis‐à‐vis de D. melanogaster et non vis‐à‐vis de D. simulans, avec un effet de bascule. D'autre part, il s'avère que ce parasite exploite beaucoup mieux son hǒte, en évitant le superparasitisme, ceci étant démontré au laboratoire et dans la nature. Enfin, il apparaǐt qu'il est capable d'allonger sa période de ponte lorsque cet hǒte est rare, ce qui ne se produit pas avec D. simulans.
Midkine expression in oral squamous cell carcinoma and leukoplakia
Authors: Jham Bruno Correia , Costa Nadia Lago , Silva Janine Mayra , de Miranda Alessandra Castro , Oliveira Jose Carlos , Silva Tarcília Aparecida , Batista Aline Carvalho
Published: May 2011

J Oral Pathol Med (2012) 41: 21–26

Background:  Midkine (MK), a 13‐kDa heparin‐binding growth factor, is overexpressed in various human cancers. However, its role in the development and progression of oral cavity squamous cell carcinoma (OCSCC) is still unclear. Thus, the aim of this study was to evaluate the expression of MK in samples of OCSCC, leukoplakia, and healthy oral mucosa (control).

Methods:  Surgically excised specimens from patients with primary OCSCC (n = 28) were immunostained for MK, Ki‐67, PCNA, p53, bcl‐2, Bax, and CD31. Besides this, MK expression was also investigated in leukoplakia and normal oral mucosa. The relationship of MK+ cells with clinical parameters (tumor location, tumor size, lymph node metastasis, and survival) and microscopic parameters (WHO histological grading, intensity of inflammation, proliferation index, apoptosis, and angiogenesis) was also evaluated.

Results:  The results showed that MK expression was increased in OCSCC in relation to leukoplakia and normal mucosa. Furthermore, MK expression was increased in late‐stage tumors (T3/T4) compared with early‐stage lesions (T1/T2). MK‐positive lesions also showed increased expression of the anti‐apoptotic protein bcl‐2.

Conclusion:  OCSCC, particularly late‐stage tumors, exhibits increased MK expression, which may be involved in tumor progression via upregulation of anti‐apoptotic genes, as shown by the augmented bcl‐2 positivity in MK‐positive tumors.
Effect of Smoking Habits on Accuracy of Implant Placement Using Mucosally Supported Stereolithographic Surgical Guides
Authors: D'haese Jan , De Bruyn Hugo
Published: May 2011

Background: Smoking is considered as a factor for implant survival and peri‐implant bone loss of dental implants. Several studies revealed the negative effect of smoking on osseointegration and its dose‐related effect.

Purpose: To evaluate the effect of smoking habits on accuracy of implant placement using mucosally supported stereolithographic surgical guides.

Material and Methods: Six OsseoSpeed™ implants (Astra Tech AB, Mölndal, Sweden) were inserted into the maxilla in 13 patients. Patients were excluded if they suffered from any systemic disease or if they were actually taking any kind of medication. Software (Mimics® 9.0) was used to fuse images of the virtually planned and actually placed implants, and locations and axes were compared between the nonsmoking and smoking subgroups. As the mucosal biotype could probably influence accuracy data, 12 reference points were defined within each patient to define a mean mucosal thickness value.

Results: In the smoking subgroup, 36 implants were placed compared with 42 in the nonsmoking subgroup. Mean coronal deviation was 1.04 mm (range: 0.29–2.45 mm) among the smokers compared with 0.80 mm among the nonsmokers (range: 0.29–1.67 mm). At apical point, mean deviation was 1.26 mm (range: 0.39–3.01 mm) among the smokers compared with 1.02 mm among the nonsmokers (range: 0.32–2.59 mm). Mean angular deviation was 2.64° (range: 0.41–6.81°) among the smokers compared with 2.57° among the nonsmokers (range: 0.16°–8.86°). Significant differences were found when comparing global coronal and apical deviation between the smokers and the nonsmokers (p < .05). Evaluating mucosal thickness, mean value was 3.19 mm (range: 2.39–4.01 mm) among the smokers compared with 2.43 mm among the nonsmokers (range: 1.44–3.03 mm).

Conclusions: Statistically significant differences were found when comparing the accuracy of dental implant placement of the smokers with the nonsmokers. Smokers have significant thicker supporting mucosal tissues compared with nonsmokers, which may explain inaccuracy due to less stability of the surgical guide or the scanning prosthesis.
RADIOGRAPHIC DIAMETER OF THE COLON IN NORMAL AND CONSTIPATED CATS AND IN CATS WITH MEGACOLON
Authors: TREVAIL TIM , GUNN‐MOORE DANIELLE , CARRERA INÉS , COURCIER EMILY , SULLIVAN MARTIN
Published: May 2011

Radiographs of 50 cats with no history of gastrointestinal disease were evaluated to establish a normal reference range for radiographic diameter of the feline colon. Thirteen cats with constipation and 26 with megacolon were also evaluated and compared with the normal cats to characterize the accuracy of the reference range and to identify a cutoff to distinguish constipation from megacolon. A ratio of maximal diameter of the colon to L5 length was the most repeatable and accurate measurement. A ratio <1.28 is a strong indicator of a normal colon (sensitivity 96%, specificity 87%). A value >1.48 is a good indicator of megacolon (sensitivity 77%, specificity 85%).
Understanding the complex mechanisms of β2‐microglobulin amyloid assembly
Authors: Eichner Timo , Radford Sheena E.
Published: May 2011

Several protein misfolding diseases are associated with the conversion of native proteins into ordered protein aggregates known as amyloid. Studies of amyloid assemblies have indicated that non‐native proteins are responsible for initiating aggregation in vitro and in vivo. Despite the importance of these species for understanding amyloid disease, the structural and dynamic features of amyloidogenic intermediates and the molecular details of how they aggregate remain elusive. This review focuses on recent advances in developing a molecular description of the folding and aggregation mechanisms of the human amyloidogenic protein β2‐microglobulin under physiologically relevant conditions. In particular, the structural and dynamic properties of the non‐native folding intermediate IT and its role in the initiation of fibrillation and the development of dialysis‐related amyloidosis are discussed.
A Quantitative Meta-Analysis on Cue-Induced Male Sexual Arousal
Authors: Kühn Simone , Gallinat Jürgen
Published: May 2011

Introduction

Visually induced sexual arousal is a common occurrence in human behavior. The cerebral underpinnings of this response have been explored in recent neuroimaging studies.

Aim

We set out to test the strength of evidence for the presence of a core network of brain regions involved in male sexual arousal elicited by erotic stimuli.

Methods

Eleven functional magnetic resonance imaging studies that presented erotic visual stimuli and compared the associated brain activity with the brain activity elicited by neutral visual stimuli were identified.

Main Outcomes Measures

Activation likelihood estimation was employed to perform quantitative meta-analyses on coordinates of brain activation in order to assess significant concordance across studies.

Results

The meta-analysis included studies on heterosexual males and revealed consistent activation in the hypothalamus, thalamus, amygdala, anterior cingulate gyrus (ACC), insula, fusiform gyrus, precentral gyrus, parietal cortex, and occipital cortex across studies. Moreover, we explored brain responses associated with a physiological marker of sexual arousal (penile tumescence) and found concurrence in hypothalamus, thalamus, bilateral insula, ACC, postcentral gyrus, and occipital gyrus.

Conclusions

This is the first quantitative meta-analysis on sexual cue reactivity and identifies a neural network consisting of cognitive (parietal cortex, ACC, thalamus, insula), emotional (amygdala, insula), motivational (precentral gyrus, parietal cortex), and physiological (hypothalamus/thalamus, insula) components constituting a core circuit of male sexual arousal in humans.
Involvement of Matrix Metalloproteinase‐2 in the Development of Medial Layer Vascular Calcification in Uremic Rats
Authors: Kumata Chiaki , Mizobuchi Masahide , Ogata Hiroaki , Koiwa Fumihiko , Kondo Fumiko , Kinugasa Eriko , Akizawa Tadao
Published: May 2011

Vascular calcification is the most important cause of cardiovascular disease in patients with chronic kidney disease (CKD). Medial layer vascular calcification, which is recognized to be an active process (i.e. the transformation of vascular smooth muscle cells into osteoblast‐like cells), is common in CKD patients. We have recently reported the possibility of an interaction between elastin degradation and medial layer vascular calcification. Matrix metalloproteinase‐2 (MMP‐2), which induces the degradation of elastin, has been implicated in the elastic calcification in arteries of dialysis patients; however, the precise mechanisms by which elastin degradation interacts with the development of vascular calcification remain to be studied. To clarify the mechanisms by which elastin degradation is involved in the development of medial layer vascular calcification in the uremic milieu, we induced aortic medial layer calcification in 5/6 nephrectomized uremic rats (male Sprague–Dawley rats) fed a diet containing high phosphate (1.2%) and lactate (20%). After 10 weeks, the rats were euthanized for the measurement of serum chemistry profiles and histological analyses. The uremic rats showed significant increases in blood pressure, serum creatinine, phosphate, and parathyroid hormone levels compared with normal rats. Von Kossa staining showed medial layer aortic calcification in the uremic rats. In calcified lesions, thin elastic lamellae were observed by elastin staining, indicating that elastin degradation could occur in the area. Furthermore, MMP‐2 expression determined by immunohistochemistry was also observed in the same area. Elastin degradation accompanied by MMP‐2 expression might be involved in the development of medial layer vascular calcification in uremic rats.
Bone Histology in Chronic Kidney Disease‐related Mineral and Bone Disorder
Authors: Kazama Junichiro James
Published: May 2011

A quantitative histological analysis of biopsied bone samples is currently regarded as the gold standard for a diagnosing procedure for bone diseases associated with chronic kidney disease‐related mineral and bone disorder. Conventionally, “bone cell activities” and “bone mineralization” are applied as two independent assessment axes, and the histology results are classified into five categories according to these axes. Recently, a new bone histology classification system called the Turnover‐Mineralization‐Volume system, which applied “cancellous bone volume” as another major assessing axis, was advocated; however, both classification systems have many unsolved problems. Clinicians must realize the limitations in evaluating bone metabolism by bone histology. We will need to establish a new classification method for renal bone diseases independent of histological findings.