bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Increase of Dietary Micronutrient Intake on Oxidative Stress Indicators in HIV/AIDS Patients
Authors: Gil Lizette , Lewis Lidianys , Martínez Gregorio , Tarinas Alicia , González Ivon , Alvarez Alejandro , Tápanes Rolando , Giuliani Attilia , León Olga Sonia , Pérez Jorge
Published: January 2006

Several recent studies in human immunodeficiency virus (HIV) patients have identified micronutrient deficiencies as affecting progression to acquired immunodeficiency syndrome (AIDS) and death. Although the mechanisms are not known, micronutrient deficiencies may exacerbate the oxidative stress induced by HIV. In addition, infection and its evolution likely lead to an increased requirement for nutritional micronutrients, especially antioxidants. To evaluate this, 40 relatively healthy, institutionalized HIV-infected individuals were recruited for assessment before or three months after fresh fruit and vegetable supply were increased due to seasonal supply. Seven-day dietary records were recorded at the beginning (December) and end of the three-month study period (March). Oxidative stress indices and CD4+, CD38+/CD8+, and CD95+ T-lymphocyte subsets were also measured at these times. No significant differences were found in calorie or protein intake across the study period, but vitamin A, C, and E intakes all increased. A number of redox indicators were modified (increase: total antioxidant status, glutathione peroxidase, and glutathione; and decrease: superoxide dismutase) during the study period. However, no change in malondialdehyde, hydroperoxides, or DNA damage was noted but a significant reduction in CD38+/CD8+ relative count was seen. Within the context and limitations of this study, the increase of dietary fruits and vegetables intake for three months had some beneficial effects on nutrition, systemic redox balance, and immune parameters in HIV-infected persons.
Dietary Intakes and Blood Concentrations of Antioxidant Vitamins in German Vegans
Authors: Waldmann Annika , Koschizke Jochen W. , Leitzmann Claus , Hahn Andreas
Published: January 2006

We report on an evaluation of intake and blood concentrations of antioxidant vitamins in a cross-sectional study of 104 German vegans, and examine the association between blood concentration of antioxidant vitamins and their intake as well as fruit and vegetable intake. Comparisons are made with dietary reference intakes and established threshold values (ETV) for blood concentrations. Mean intakes of vitamin C, E, and β-carotene were higher than actual recommendations, but comparable to reported intakes in other vegan cohorts. Mean blood concentrations were 0.76 μmol/L for β-carotene and 117 μmol/L for vitamin C, so that nearly all participants showed concentrations that were above the ETV for the prevention of chronic diseases. Although mean vitamin E intake was 24.8 mg/day, only 32% of female and 18% of male participants showed plasma concentrations above the ETV. However, the mean vitamin E/cholesterol ratio was high (5.97), indicating a good protection of low-density lipoprotein (LDL) against peroxidation. Of the reported antioxidant vitamins, only plasma vitamin C concentration was a good biomarker of fruit and vegetable intake. The high concentration of antioxidative compounds in plasma may be one of the reasons for the lower incidence of chronic diseases in people consuming a plant-only diet.
Spontane Dissektion der A. subclavia und ihrer Äste
Authors: Arning
Published: January 2006

Eine 51 Jahre alte Frau stellte sich mit seit Tagen anhaltendem Schwindel in unserer Gefäßambulanz vor. Das MRT wies einen Kleinhirninfarkt rechts nach. Sonographisch fanden wir eine Dissektion der A. subclavia rechts mit einem Wandhämatom, das sich in das erste Segment der A. vertebralis und in den Truncus thyreocervicalis ausbreitete sowie eine Dissektion der A. vertebralis links im kraniozervikalen Übergang. Die Veränderungen bildeten sich im Verlauf zurück: nach 2 Monaten waren alle Stenosen rekanalisiert, nach 7 Monaten war das Wandhämatom nicht mehr nachweisbar. Es gab keinen Anhalt für eine traumatische oder iatrogene Ursache der Dissektion. Eine Aortendissektion wurde mit MRT ausgeschlossen. Es handelt sich offenbar um den sehr seltenen Befund einer spontanen A. subclavia-Dissektion.
Coil embolization of an infected superior gluteal artery pseudoaneurysm caused by methicillin-resistant Staphylococcus aureus
Authors: Schindera  , Anderson  , Triller
Published: January 2006

We describe the successful selective coil embolization of an infected superior gluteal pseudoaneurysm secondary to methicillin-resistant Staphylococcus aureus (MRSA) in a 36-year old women. The patient presented with a long history of drug abuse and perisacral abscesses due to chronic sacroilitis. The chosen strategy provides a safe and successful management of infected false gluteal artery aneurysm.
Aufklärungs- und Informationsgespräche im Krankenhaus
Authors: Luderer Christiane , Behrens Johann
Published: January 2006

Das Ziel dieser deskriptiven Studie war die Darstellung von Kommunikationsstrukturen im Kontext von Aufklärungsgesprächen des medizinischen Personals und von Informationsgesprächen des pflegerischen Personals mit Patienten in der stationären Versorgung. Die Rücklaufquote der postalischen Befragung betrug 42 Prozent. Es beteiligten sich 144 Pflegende und 46 Ärzte verschiedener Fachbereiche eines Klinikums der Maximalversorgung in den neuen Bundesländern. Die Untersuchung zeigte, vor welchem situativen Hintergrund sich Gespräche mit Patienten zu Diagnose und Krankheitsverlauf gestalten. Es wurden formelle (z.B. Visiten, Übergabegespräche, Teambesprechungen und Dokumentationssysteme) und informelle (z.B. Kollegengespräche, Arbeitsatmosphäre) Kommunikationsstrukturen aufgezeigt, deren inhomogene Ausgestaltung eine Informationsweitergabe zum Aufklärungsstand der Patienten unter Pflegenden und Medizinern einer Station erschwert. Der situative Kontext der Gespräche mit den Patienten wird vor allem dadurch bestimmt, dass die Gesprächseröffnung spontan durch die Patienten im Rahmen pflegerischer oder medizinischer Interventionen erfolgt. Der unbekannte Aufklärungsstand der Patienten kann das Personal verunsichern und zu Vermeidungstaktiken in der Gesprächsführung führen. Weiterhin wird die defizitäre Vermittlung kommunikativer Kompetenzen im Rahmen der pflegerischen und medizinischen Ausbildung offenbart, und es wird deutlich, dass den Pflegenden die rechtlichen Vorgaben zum Führen von Informationsgesprächen wenig bekannt sind. Eine Dokumentation des Informiertheitsgrades der Patienten kann kommunikative Defizite zwar nicht ausgleichen, aber überbrücken. Sie ermöglicht einen kongruenten, authentischen Umgang des Personals mit den Patienten.
Sturzfolgen bei geriatrischen Krankenhauspatienten
Authors: Krause Tom
Published: January 2006

In der Geriatrie ist eine höhere Sturz-Inzidenz als in anderen medizinischen Fachbereichen feststellbar. Über die Sturzfolgen bei geriatrischen Patienten ist wenig bekannt. Ziel war die Beschreibung von Verletzungsfolgen nach Sturzereignissen, die Lokalisation von Verletzungen und die Auswirkungen auf die stationäre Verweildauer. Methoden: Es wurden die Daten eines standardisierten Sturzprotokolls für alle Sturzereignisse des Jahres 2003 einer geriatrischen Klinik ausgewertet. Zusätzlich lagen Angaben aus dem Krankenhaus-Informationssystem vor. Ergebnisse: Im Berichtsjahr 2003 konnten 345 Sturz-Patienten (506 Stürze) und 1763 Nicht-Stürzer verzeichnet werden. Verletzungen oder Schmerzen waren bei 37,2% der Stürze die Folge. Nur 5 Patienten (1,4%) erlitten eine Fraktur. Unterschiede zwischen Stürzern und Nicht-Stürzern waren bei den Variablen «Verweildauer» (28,8 Tage vs 19,5 Tage), «weibliches Geschlecht» (61,4% vs 69,4%) und «Barthel-Index» (40,2 Punkte vs 48,5 Punkte im Mittel) feststellbar. Schlussfolgerungen: Stürze sind ein Indikator für komplizierte Behandlungsverläufe im Sinne einer längeren Verweildauer. Der Vermeidung schwerer Verletzungen sollte ein ebenso großer Stellenwert wie der Sturzvermeidung beigemessen werden.
Morbidity in Superficial Thrombophlebitis and its Potential Surgical Prevention
Authors: Rohrbach  , Mouton  , Naef  , Otten  , Zehnder  , Wagner
Published: January 2006

Thrombophlebitis is a common condition which can lead to deep venous thrombosis (DVT) and subsequent pulmonary embolism (PE). Thrombophlebitis can reach the deep venous system via the long or short saphenous vein or via perforating veins. Between the 1 st of January 1999 and the 31 st of December 2000 a total of 17 cases of superficial (or ascending) thrombophlebitis closer than 5 cm to the deep venous system were surgically treated in our clinic. 14 times the long saphenous vein was affected and 3 times the short saphenous vein. The age of the nine females and seven males ranged from 31 to 77 (mean of 54.6) years. Duplex ultrasound was performed in all patients. In the case of a deep venous thrombosis (four cases) a computer tomography scan (CT) of the pelvis and abdomen was performed to define the extension of DVT. In all 17 (100%) cases a high ligation (crossectomy) and in four (23.5%) cases a venous thrombectomy was performed. In all of these four cases the DVT was limited to the common femoral vein. In all seventeen procedures including venous thrombectomy there was no mortality and no relevant morbidity. Mean hospitalization time was 3.1 days for crossectomy with thrombectomy, and 1.8 days for crossectomy alone. Follow-up has been so far uneventful (mean follow-up time being 12 months in the case of a DVT). In the literature there is no clear concept of how to treat, conservatively or operatively, ascending thrombophlebitis. The surgical procedure can be performed under local anesthesia, and it is safe and efficient.
Long-term-Outpatient Therapy with a Left Ventricular Assist Device
Authors: Grapow  , Todorov  , Bernet  , Zerkowski
Published: January 2006

Wir berichten über die erste erfolgreiche ambulante Langzeit-Betreuung eines Patienten mit kombinierter dilatativer und ischämischer Kardiomyopathie nach Implantation eines implantierbaren, pulsatilen Linksherzunterstützungssystem (LVAD; Novacor), in der Schweiz. Der Patient (112 kg, 191 cm, Blutgruppe A) entwickelte ein mit medizinischen Therapiemassnahmen nicht mehr behandelbares terminales Herzversagen (New York Heart Association Class (NYHA) IV), während er auf eine orthothope Herztransplantation wartete. Als selbstständiger Graphikdesigner befürchtete der Patient Langzeit-Hospitalisation gefolgt vom Konkurs seines Unternehmens. Aus diesen Gründen entschieden wir uns für eine Implantation eines Novacor LVAD und führten diesen Eingriff bei erneuter, nicht reversibler Dekompensation als Überbrückung bis zur Herztransplantation mit optional (bei günstigem Verlauf) ambulanter Betreuung durch. Der Patient wurde mehr als fünf Monate durch das System unterstützt. Er verbesserte sich funktionell gemäss NYHA-Klassifikation in Klasse I und wurde fünf Wochen nach Implantation aus der stationären Behandlung entlassen. Er kehrte zurück in sein "normales" Leben und begann wieder zu 100 % zu arbeiten. Das LVAD ermöglichte es ihm, nahezu alle Aktivitäten durchzuführen. Fünf Monate (151 Tage) nach Implantation erhielten wir ein passendes Organangebot und führten die orthotope Herztransplantation durch. Die Verwendung eines implantierbaren, pulsatilen Linksherzunterstützungssystem und erfolgreiche ambulante Betreuung unseres Patienten erwies sich als sicher, zuverlässig, lebensrettend, Lebensqualität verbessernd und könnte eine wichtige Alternative in puncto ökonomischer Belastung in der Herzinsuffizienztherapie sein.
A Case of Intestinal Obstruction due to Phytobezoar - An Alternative Surgical Approach
Authors: Aslan  , Ünal  , Karagüzel  , Melikoglu
Published: January 2006

We report a 5-year-old patient with phytobezoar mimicking acute appendicitis preoperatively. During laparotomy, it was detected that terminal ileum was obstructed by several fragments of rubbery material. Bezoar was milked into the large bowel, and phytobezoar including tangerine residues was evacuated via appendix stump because of severe distended cecum, and high risk of the anastomotic leakage and intraperitoneal contamination following enterotomy of the inflamated and ischemic ileum. Postoperative course was uneventful. To date, such a procedure has not been described. We suggest that milking of vegetable fibers into the cecum and then emptying via appendix stump may be an alternative treatment of phytobezoar localizing in terminal ileum.
Die Rolle von Absichten bei der automatischen Verarbeitung visuell-räumlicher Reizinformation
Authors: Ansorge Ulrich
Published: January 2006

Zusammenfassung. Wird visuell-räumliche Reizinformation automatisch verarbeitet? Psychologische Experimente scheinen das zu belegen. Reize, die plötzlich am Rand des Blickfelds erscheinen, ziehen die Aufmerksamkeit unwillkürlich auf den Ort ihres Erscheinens, selbst dann, wenn wir einen anderen Ort beachten wollen. Und Reizpositionen aktivieren Reaktionen, obwohl die Positionen “irrelevant“ sind. In einer Reihe von Arbeiten konnte allerdings nachgewiesen werden, dass diese Effekte in erheblichem Maß auf Absichten beruhen: Plötzlich erscheinende Reize ziehen die Aufmerksamkeit vor allem bei hoher Passung zwischen Suchabsichten und irrelevanten Reizen (oder Reizmerkmalen) an, und Reizpositionen aktivieren Reaktionen, wenn die Probanden die entsprechende räumliche Information benutzen, um zwischen Reaktionsalternativen zu unterscheiden. Was als automatische Verarbeitung erscheint, könnte daher auf einem allgemeineren Verarbeitungsprinzip beruhen: einer Passung der Merkmale vermeintlich irrelevanter Reize zu den willentlich ausgewählten Kriterien für die Verarbeitung relevanter Merkmale.
Perzeptive Expertise von Badmintonspielern
Authors: Hagemann Norbert , Strauß Bernd
Published: January 2006

Zusammenfassung. Personen können allgemein sehr gut menschliche Bewegungen wahrnehmen und darüber hinaus auch sehr ähnliche Bewegungen diskriminieren. Perzeptive Expertise im Sport zeigt sich u.a. in einer sehr differenzierten Wahrnehmung gegnerischer Bewegungsmuster. Durch die Kombination einer zeitlichen und räumlichen Entzugstechnik bei der Präsentation von Bewegungssequenzen wird der zeitlich-räumliche Verlauf der visuellen Informationsaufnahme bestimmt. Spieler der 1. und 2. Badmintonbundesliga (n = 20), Bezirksliga (n = 23) und Novizen (n = 20) hatten die Aufgabe, an einem Computer die Schlagrichtungen von 168 Badmintonschlägen vorherzusagen. Experten können schon aus der Ausholbewegung (von 160 ms bis 80 ms vor Ballkontakt) Informationen über den potenziellen Auftreffpunkt entnehmen. Außerdem zeigte sich, dass zum Auftakt der Schlagbewegung (bis 160 ms vor Ballkontakt) die Bewegung proximaler Körperregionen (Rumpf) und zum Ende (bis Ballkontakt) distaler Körperregionen (Arm und Schläger) zur Vorhersage der Schlagrichtung genutzt werden.
Suizidselbsthilfe-Foren im Internet: Eine Befragungsstudie
Authors: Eichenberg Christiane , Otte Thomas A. , Fischer Gottfried
Published: January 2006

Zusammenfassung. Theoretischer Hintergrund: Im klinischen Diskurs ist die Beurteilung der Gefahren bzw. des Nutzens von Internetdiskussionsgruppen, in denen sich Menschen mit suizidalen Gedanken austauschen, sehr heterogen. Es überwiegen aber Stimmen, die von einer immensen Schädlichkeit dieser Foren ausgehen und die im extremsten Fall staatliche Maßnahmen zur Schließung der Foren fordern. Methode: Um spekulativen Annahmen über die Funktionen dieser “Suizidforen“ empirische Evidenz gegenüberzustellen, wurde in einem deutschsprachigem Forum für Suizidgefährdete eine Online-Befragungsstudie (N = 164; je 50% männlich bzw. weiblich; 88% ≤ 30 Jahre) durchgeführt. Ergebnisse: Es ließen sich drei Nutzertypen bestimmen (der “konstruktiv Hilfesuchende“, der “ambivalent Hilfesuchende“, der “unspezifisch Motivierte“), die sich mit hohen Effektstärken hinsichtlich ihrer Motive ein solches Forum aufzusuchen als auch in den klinisch relevanten Auswirkungen der Teilnahme an einer solchen Community unterschieden. Schlussfolgerungen: In ihrer Gesamtheit widersprechen die vorliegenden Ergebnisse deutlich der Annahme, “Suizid-Foren“ im Internet stellten pauschal ein Gefährdungspotenzial dar.
Impact of land use on Costa Rican tropical montane cloud forests: Sensitivity of orographic cloud formation to deforestation in the plains
Authors: Ray Deepak K. , Nair Udaysankar S. , Lawton Robert O. , Welch Ronald M. , Pielke Roger A.
Published: January 2006

The current study provides new insights into the coupling of land use in lowland and premontane regions (i.e., regions below 1000 m) and orographic cloud formation over the Monteverde cloud forests. Rawinsondes launched during the Land Use Cloud Interaction Experiment (LUCIE) together with those from the National Centers for Environmental Prediction (NCEP) provided profiles that were used to drive the Colorado State University Regional Atmospheric Modeling System (CSU RAMS) model, which simulated three realistic land use scenarios (pristine forests, current conditions and future deforestation). For current conditions, the model‐simulated clouds were compared against those observed at hourly intervals by the Geostationary Environmental Observational Satellite–East (GOES E) satellite. The model performed best on 6 different days. The model‐simulated profiles of dew point and air temperatures were compared with the observed profiles from rawinsondes for these days. There was generally very good agreement below 700 mb, the region of the atmosphere most crucial to the cloud forests. The average model simulations for the 6 days show that when the lowland and premontane regions were completely forested, the orographic cloud bank intersected the mountains at the lowest elevations, covered the largest land surface area and remained longest on the surface in the montane regions. Deforestation has decreased the cloud forest area covered with fog in the montane regions by around 5–13% and raised the orographic cloud bases by about 25–75 m in the afternoon. The model results show that further deforestation in the lowland and premontane regions would lead to around 15% decrease in the cloud forest area covered with fog and also raise the orographic cloud base heights by up to 125 m in the afternoon. The simulations show that deforestation in the lowland and premontane regions raises surface sensible heat fluxes and decreases latent heat fluxes. This warms the air temperature and results in a lower dew point temperature of air masses that blow over the lowland and premontane regions. These air masses when lifted form the orographic cloud bank at higher elevations.
Transpressive shear related to arc magmatism: The Paleoproterozoic Storsjön‐Edsbyn Deformation Zone, central Sweden
Authors: Bergman Stefan , Sjöström Håkan , Högdahl Karin
Published: January 2006

The polyphase, 15–30 km wide and >200 km long Storsjön‐Edsbyn Deformation Zone (SEDZ) apparently separates two major Paleoproterozoic provinces in central Sweden. Four main phases of deformation have been recognized along the zone; associated high‐strain rocks are characterized by their mineralogy, microstructures, kinematic patterns, magnetic signatures, and relative ages. The mineral and stretching lineations are consistently steeply to moderately plunging. Analysis of mesoscopic shear zone populations of different generations suggests that most displacements are compatible with north‐south to northeast‐southwest bulk regional shortening. The structural analysis suggests that the main ductile deformation along the SEDZ was due to dextral transpression with a steep coaxial component. Field evidence combined with published age data constrain the main deformation to the time interval circa 1.7–1.3 Ga. Synkinematic titanite from a ductile protomylonite in the SEDZ yields an U‐Pb age of 1674 ± 6 Ma. The combined results imply transpressive deformation broadly synchronous with, and spatially related to, volcanism and plutonism in a continental margin magmatic arc setting.
The plasma source of the Large Plasma Device at University of California, Los Angeles
Authors: Leneman D. , Gekelman W. , Maggs J.
Published: January 2006

The Large Plasma Device at the University of California, Los Angeles has recently been upgraded. The plasma is now 18m long (the device is 22m long) and is designed to produce a 0.36T axial magnetic field. Its plasma source has also been upgraded, incorporating a 1m square heater, a 72cm diameter cathode and anode, and associated heat shields and reflectors. The barium oxide coated cathode is heated to 750°C and can produce plasmas of diameters up to 0.9m diameter (depending on the magnetic field configuration), and densities up to 7×1012cm−3 with a spatial uniformity of ±10%.
Tomographic imaging of resistive mode dynamics in the Madison Symmetric Torus reversed-field pinch
Authors: Franz P. , Marrelli L. , Piovesan P. , Predebon I. , Bonomo F. , Frassinetti L. , Martin P. , Spizzo G. , Chapman B. E. , Craig D. , Sarff J. S.
Published: January 2006

A detailed study of the dynamics and magnetic topological effects of resistive-tearing modes is presented for different operational regimes in the Madison Symmetric Torus reversed-field pinch [R. N. Dexter et al., Fusion Technol. 19, 131 (1991)]. Soft-x-ray tomography and magnetic measurements, along with numerical reconstruction of magnetic-field lines with the ORBIT code [R. B. White and M. S. Chance, Phys. Fluids 27, 2455 (1984)], have been employed. Magnetic-mode dynamics has been investigated in standard plasmas during the transition to the quasi-single helicity state, in which a single mode dominates the mode spectrum. Single helical soft-x-ray structures are studied with tomography in these cases. These structures are associated with magnetic islands, indicating that helical flux surfaces appear in the plasma. Mode dynamics has also been examined during auxiliary inductive current drive, the goal of which is to reduce the tearing-mode amplitudes. In this case the phenomenology of the soft-x-ray structures appearing in the plasma is more complex. In fact, when a quasi-single helicity spectrum occurs, a single island bigger than in the standard case is usually found. On the other hand, when all modes decrease, two helical soft-x-ray structures are observed, with the same helicity as the two innermost resonant modes. This constitutes the first direct evidence of magnetic-chaos reduction during auxiliary inductive current drive, which is responsible for the achievement of the best confinement in the reversed-field pinch configuration up to now.
An extended hindered-rotor model with incorporation of Coriolis and vibrational-rotational coupling for calculating partition functions and derived quantities
Authors: Vansteenkiste P. , Van Neck D. , Van Speybroeck V. , Waroquier M.
Published: January 2006

Large-amplitude motions, particularly internal rotations, are known to affect substantially thermodynamic functions and rate constants of reactions in which flexible molecules are involved. Up to now all methods for computing the partition functions of these motions rely on the Pitzer approximation of more than 50 years ago, in which the large-amplitude motion is treated in complete independence of the other (vibrational) degrees of freedom. In this paper an extended hindered-rotor model (EHR) is developed in which the vibrational modes, treated harmonically, are correctly separated from the large-amplitude motion and in which relaxation effects (the changes in the kinetic-energy matrix and potential curvature) are taken into account as one moves along the large-amplitude path. The model also relies on a specific coordinate system in which the Coriolis terms vanish at all times in the Hamiltonian. In this way an increased level of consistency between the various internal modes is achieved, as compared with the more usual hindered-rotor (HR) description. The method is illustrated by calculating the entropies and heat capacities on 1,3-butadiene and 1-butene (with, respectively, one and two internal rotors) and the rate constant for the addition reaction of a vinyl radical to ethene. We also discuss various variants of the one-dimensional hindered-rotor scheme existing in the literature and its relation with the EHR model. It is argued why in most cases the HR approach is already quite successful.
Hall current layer formation in arc discharge across magnetic field and transfer of fast ions out of discharge
Authors: Bender E. D. , Dimov G. I. , Krivenko A. S. , Razorenov V. V.
Published: January 2006

In the work presented here the geometry of the Hall current layer in a plasma of the vacuum arc discharge in the transverse magnetic field are analyzed. The extraction of an intense pure flux of fast ions generated in the cathode spots with the help of the Hall layer is discussed. Experiments on the arc source of carbon fast ions are described. The anode geometry adequate to the mechanism of the arc current passage through the transverse magnetic field is found out experimentally. Up to 70% of fast ions are extracted out of the arc discharge in the arched magnetic field. In experiments, the Hall current layer formation in the vacuum arc discharge across magnetic field is confidently confirmed.
Control of translating velocity using pulse field on field-reversed configuration plasmas
Authors: Fujino T. , Gota H. , Hasegawa Y. , Kanamaru Y. , Fujimoto K. , Asai T. , Takahashi T. , Nogi Y.
Published: January 2006

The translating velocity of a field-reversed configuration plasma is controlled using a pulse mirror field. Numerical calculations are carried out, using a flux-conserving moving mirror coil, to simulate the motion of the plasma subject to the pulse field. The calculations suggest that it is possible to stop the plasma smoothly without reflection under the pulse mirror coil when the strength of the mirror is changed depending on the velocity of the plasma. In the experiment, the pulse field is produced by a current flowing in a one-turn coil installed inside a theta-pinch coil. It is demonstrated that the translating plasma passing under the one-turn coil is reflected and stops depending on the strength of the pulse field. The optimum strength of the field to stop the plasma without reflection is in good agreement with the estimation of the calculations.
Low-dislocation-density strain relaxation of SiGe on a SiGe∕SiGeC buffer layer
Authors: Wong L. H. , Liu J. P. , Ferraris C. , Wong C. C. , Jonatan M. C. , White T. J. , Chan L.
Published: January 2006

We report an observation of strain relaxation in lattice-mismatched heteroepitaxial Si1−xGex layers, accompanied by a reduction in threading dislocation density (TDD). This occurs on a Si0.77Ge0.23 layer grown on top of alternating layers of Si0.77Ge0.23∕Si0.76Ge0.23C0.01. The present scheme allows us to grow a high-quality 85% relaxed Si0.77Ge0.23 layer with a TDD of ∼104∕cm2. The high-resolution transmission electron microscope results showed the presence of Si1−x−yGexCy domains (with x⩽0.23 and y⩽0.01) after annealing at 1000°C. We infer that the formation of these domains assist the low TDD relaxation by releasing the epitaxial misfit strain as localized discrete strain and by blocking the propagation of misfit dislocations.
Glue-free tuning fork shear-force microscope
Authors: Mühlschlegel P. , Toquant J. , Pohl D. W. , Hecht B.
Published: January 2006

A scanning near-field optical microscope without any glued parts is described. Key elements are the optical fiber probe/tuning fork junction and the piezotube scanner assembly. In both cases, fixation is achieved by means of controlled pressure and elastic deformation. The avoidance of glued connections was found to improve the Q factor of the shear-force sensor as well as to facilitate the replacement of the fiber probe and other parts of the scanner head. We present approach curves and shear-force images that demonstrate the performance and stability of the system.
Growth of silicon bump induced by swift heavy ion at the silicon oxide-silicon interface
Authors: Carlotti J. -F. , Touboul A. D. , Ramonda M. , Caussanel M. , Guasch C. , Bonnet J. , Gasiot J.
Published: January 2006

Thin silicon oxide layers on silicon substrates are investigated by scanning probe microscopy before and after irradiation with 210 MeV Au+ ions. After irradiation and complete chemical etching of the silicon oxide layer, silicon bumps grown on the silicon surface are observed. It is shown that each impinging ion induces one silicon bump at the interface. This observation is consistent with the thermal spike theory. Ion energy loss is transferred to the oxide and induces local melting. Silicon-bump formation is favored when the oxide and oxide-silicon interface are silicon rich.
Low-temperature growth of crystalline GaN films using energetic neutral atomic-beam lithography/epitaxy
Authors: Mueller Alexander H. , Akhadov Elshan A. , Hoffbauer Mark A.
Published: January 2006

Crystalline and polycrystalline gallium nitride films have been grown on bare c-axis-oriented sapphire at low temperatures (100 °C to 500 °C) using energetic neutral atom-beam lithography/epitaxy. Surface chemistry is activated by exposing substrates to nitrogen atoms with kinetic energies between 0.5 and 5.0 eV and a simultaneous flux of Ga metal, allowing low-temperature growth of GaN thin films. The as-grown GaN films show semiconducting properties, a high degree of crystallinity, and excellent epitaxial alignment. This method of low-temperature nitride film growth opens opportunities for integrating novel substrate materials with group III nitride technologies.
Measurement of the valence-band offset at the epitaxial MgO-GaAs(001) heterojunction by x-ray photoelectron spectroscopy
Authors: Lu Y. , Le Breton J. C. , Turban P. , Lépine B. , Schieffer P. , Jézéquel G.
Published: January 2006

The electronic band structure at the interface of the MgO-GaAs(001) tunnel contact has been experimentally studied. X-ray photoelectron spectroscopy has been used to measure the valence-band offset at the MgO-GaAs(001) heterojunction interface. The valence-band offset ΔEV is determined to be 4.2±0.1eV. As a consequence, a nested “type-I” band alignment with a conduction-band offset of ΔEC=2.2±0.1eV is found. The accurate determination of the valence and conduction band offsets is important for the fundamental understanding of the tunnel spin injection in GaAs.
Intercellular coupling amplifies fate segregation during
Caenorhabditis elegans
vulval development
Authors: Giurumescu Claudiu A. , Sternberg Paul W. , Asthagiri Anand R.
Published: January 2006

During vulval development in
Caenorhabditis elegans
, six precursor cells acquire a spatial pattern of distinct cell fates. This process is guided by a gradient in the soluble factor, LIN-3, and by direct interactions between neighboring cells mediated by the Notch-like receptor, LIN-12. Genetic evidence has revealed that these two extracellular signals are coupled: lateral cell-cell interactions inhibit LIN-3-mediated signaling, whereas LIN-3 regulates the extent of lateral signaling. To elucidate the quantitative implications of this coupled network topology for cell patterning during vulval development, we developed a mathematical model of LIN-3/LIN-12-mediated signaling in the vulval precursor cell array. Our analysis reveals that coupling LIN-3 and LIN-12 amplifies cellular perception of the LIN-3 gradient and polarizes lateral signaling, both of which enhance fate segregation beyond that achievable by an uncoupled system.
Long-distance lateral diffusion of human Rad51 on double-stranded DNA
Authors: Granéli Annette , Yeykal Caitlyn C. , Robertson Ragan B. , Greene Eric C.
Published: January 2006

Rad51 is the primary eukaryotic recombinase responsible for initiating DNA strand exchange during homologous recombination. Although the subject of intense study for over a decade, many molecular details of the reactions promoted by Rad51 and related recombinases remain unknown. Using total internal reflection fluorescence microscopy, we directly visualized the behavior of individual Rad51 complexes on double-stranded DNA (dsDNA) molecules suspended in an extended configuration above a lipid bilayer. Here we show that complexes of Rad51 can bind to and slide freely along the helical axis of dsDNA. Sliding is bidirectional, does not require ATP hydrolysis, and displays properties consistent with a 1D random walk driven solely by thermal diffusion. The proteins move freely on the DNA for long periods of time; however, sliding terminates and the proteins become immobile upon encountering the free end of a linear dsDNA molecule. This study provides previously uncharacterized insights into the behaviors of human Rad51, which may apply to other members of the RecA-like family of recombinases.
Cleavage of the papillomavirus minor capsid protein, L2, at a furin consensus site is necessary for infection
Authors: Richards Rebecca M. , Lowy Douglas R. , Schiller John T. , Day Patricia M.
Published: January 2006

Papillomaviruses (PV) comprise a large family of nonenveloped DNA viruses that include the oncogenic PV types that are the causative agents of human cervical cancer. As is true of many animal DNA viruses, PV are taken into the cell by endocytosis and must escape from the endosomal compartment to the cytoplasm to initiate infection. Here we show that this step depends on the site-specific enzymatic cleavage of the PV minor virion protein L2 at a consensus furin recognition site. Cleavage by furin, a cell-encoded proprotein convertase, is known to be required for endosome escape by many bacterial toxins. However, to our knowledge, furin has not been previously implicated in the viral entry process. This step is potentially a target for PV inhibition.
Identification of a conserved bacterial protein secretion system in
Vibrio cholerae
using the
Dictyostelium
host model system
Authors: Pukatzki Stefan , Ma Amy T. , Sturtevant Derek , Krastins Bryan , Sarracino David , Nelson William C. , Heidelberg John F. , Mekalanos John J.
Published: January 2006

The bacterium
Vibrio cholerae
, like other human pathogens that reside in environmental reservoirs, survives predation by unicellular eukaryotes. Strains of the O1 and O139 serogroups cause cholera, whereas non-O1/non-O139 strains cause human infections through poorly defined mechanisms. Using
Dictyostelium discoideum
as a model host, we have identified a virulence mechanism in a non-O1/non-O139
V. cholerae
strain that involves extracellular translocation of proteins that lack N-terminal hydrophobic leader sequences. Accordingly, we have named these genes “VAS” genes for virulence-associated secretion, and we propose that these genes encode a prototypic “type VI” secretion system. We show that
vas
genes are required for cytotoxicity of
V. cholerae
cells toward
Dictyostelium
amoebae and mammalian J774 macrophages by a contact-dependent mechanism. A large number of Gram-negative bacterial pathogens carry genes homologous to
vas
genes and potential effector proteins secreted by this pathway (i.e., hemolysin-coregulated protein and VgrG). Mutations in
vas
homologs in other bacterial species have been reported to attenuate virulence in animals and cultured macrophages. Thus, the genes encoding the VAS-related, type VI secretion system likely play an important conserved function in microbial pathogenesis and represent an additional class of targets for vaccine and antimicrobial drug-based therapies.
A plausible model of phyllotaxis
Authors: Smith Richard S. , Guyomarc'h Soazig , Mandel Therese , Reinhardt Didier , Kuhlemeier Cris , Prusinkiewicz Przemyslaw
Published: January 2006

A striking phenomenon unique to the kingdom of plants is the regular arrangement of lateral organs around a central axis, known as phyllotaxis. Recent molecular-genetic experiments indicate that active transport of the plant hormone auxin is the key process regulating phyllotaxis. A conceptual model based on these experiments, introduced by Reinhardt
et al.
[Reinhardt, D., Pesce, E. R., Stieger, P., Mandel, T., Baltensperger, K.,
et al.
(2003)
Nature
426, 255–260], provides an intuitively plausible interpretation of the data, but raises questions of whether the proposed mechanism is, in fact, capable of producing the observed temporal and spatial patterns, is robust, can start
de novo
, and can account for phyllotactic transitions, such as the frequently observed transition from decussate to spiral phyllotaxis. To answer these questions, we created a computer simulation model based on data described previously or in this paper and reasonable hypotheses. The model reproduces, within the standard error, the divergence angles measured in
Arabidopsis
seedlings and the effects of selected experimental manipulations. It also reproduces distichous, decussate, and tricussate patterns. The model thus offers a plausible link between molecular mechanisms of morphogenesis and the geometry of phyllotaxis.
Nuclear localization of the
Saccharomyces cerevisiae
ribonucleotide reductase small subunit requires a karyopherin and a WD40 repeat protein
Authors: Zhang Zhen , An Xiuxiang , Yang Kui , Perlstein Deborah L. , Hicks Leslie , Kelleher Neil , Stubbe JoAnne , Huang Mingxia
Published: January 2006

Ribonucleotide reductase (RNR) catalyzes the reduction of ribonucleotides to the corresponding deoxyribonucleotides and is an essential enzyme for DNA replication and repair. Cells have evolved intricate mechanisms to regulate RNR activity to ensure high fidelity of DNA replication during normal cell-cycle progression and of DNA repair upon genotoxic stress. The RNR holoenzyme is composed of a large subunit R1 (α, oligomeric state unknown) and a small subunit R2 (β
2
). R1 binds substrates and allosteric effectors; R2 contains a diferric-tyrosyl radical [(Fe)
2
-Y·] cofactor that is required for catalysis. In
Saccharomyces cerevisiae
, R1 is predominantly localized in the cytoplasm, whereas R2, which is a heterodimer (ββ′), is predominantly in the nucleus. When cells encounter DNA damage or stress during replication, ββ′ is redistributed from the nucleus to the cytoplasm in a checkpoint-dependent manner, resulting in the colocalization of R1 and R2. We have identified two proteins that have an important role in ββ′ nuclear localization: the importin β homolog Kap122 and the WD40 repeat protein Wtm1. Deletion of either
WTM1
or
KAP122
leads to loss of ββ′ nuclear localization. Wtm1 and its paralog Wtm2 are both nuclear proteins that are in the same protein complex with ββ′. Wtm1 also interacts with Kap122
in vivo
and requires Kap122 for its nuclear localization. Our results suggest that Wtm1 acts either as an adaptor to facilitate nuclear import of ββ′ by Kap122 or as an anchor to retain ββ′ in the nucleus.
Secondary sex ratios and male lifespan: Damaged or culled cohorts
Authors: Catalano Ralph , Bruckner Tim
Published: January 2006

Population stressors reportedly reduce the human secondary sex ratio (i.e., the odds of a newborn's being male) by, among other mechanisms, inducing the spontaneous abortion of males who would have been born live had mothers not been stressed. Controversy remains as to whether these abortions result from reduced maternal tolerance of males at the low end of a relatively constant distribution of survivability (i.e., the “culled cohort” explanation) or from shifts in the whole distribution of survivability such that more males fall below a relatively constant criterion of maternal tolerance for low survivability (i.e., the “damaged cohort” explanation). These alternatives make opposing predictions regarding the relationship between the secondary sex ratio and lifespan of male birth cohorts. We test the hypothesis that the secondary sex ratio among Swedish cohorts born in the years 1751 through 1912 predicts male cohort life expectancy at birth (i.e., realized lifespan). Our results support the culled cohort argument. We argue that these findings have implications for the basic literature concerned with temporal variation in the secondary sex ratio, for more applied work concerned with the fetal origins of adult health, and for public health surveillance.
In vivo
identification of ribonucleoprotein-RNA interactions
Authors: Zielinski Jennifer , Kilk Kalle , Peritz Tiina , Kannanayakal Theresa , Miyashiro Kevin Y. , Eiríksdóttir Emelía , Jochems Jeanine , Langel Ûlo , Eberwine James
Published: January 2006

To understand the role of RNA-binding proteins (RBPs) in the regulation of gene expression, methods are needed for the
in vivo
identification of RNA-protein interactions. We have developed the peptide nucleic acid (PNA)-assisted identification of RBP technology to enable the identification of proteins that complex with a target RNA
in vivo
. Specific regions of the 3′ and 5′ UTRs of
ankylosis
mRNA were targeted by antisense PNAs transported into cortical neurons by the cell-penetrating peptide transportan 10. An array of proteins was isolated in complex with or near the targeted regions of the
ankylosis
mRNA through UV-induced crosslinking of the annealed PNA-RNA-RBP complex. The first evidence for pharmacological modulation of these specific protein-RNA associations was observed. These data show that the PNA-assisted identification of the RBP technique is a reliable method to rapidly identify proteins interacting
in vivo
with the target RNA.
Oviposition responses to patch quality in the larch ladybird Aphidecta obliterata (Coleoptera: Coccinellidae): effects of aphid density, and con- and heterospecific tracks
Authors: Oliver T.H. , Timms J.E.L. , Taylor A. , Leather S.R.
Published: January 2006

The effects and persistence of oviposition-deterring semiochemical cues from conspecific and heterospecific larval tracks on the oviposition rate of Aphidecta obliterata (Linnaeus) females were investigated. In addition, the effects of varying aphid prey density were considered and also whether any resulting response originated from differential nutritional status of females and/or due to aphid odour stimuli. The existence of oviposition responses to conspecific egg chemicals was also considered. Gravid A. obliterata females were deterred from oviposition by conspecific larval tracks and the effect was density dependent. Females actively avoided searching in these contaminated areas. Tracks induced a significant effect on oviposition for up to three days. Heterospecific tracks of the coccinellid Adalia bipunctata (Fabricius) or the chrysopid Chrysoperla carnea (Stephens) did not induce any oviposition response in A. obliterata females. Increasing aphid density induced increased oviposition rate in A. obliterata females. Nutritional status of females was an important factor in the relationship between aphid density and oviposition rate, but aphid associated cues (odours) were not. There was an inhibitory effect of extracts of conspecific egg-surface chemicals on oviposition by A. obliterata females. In the field, cannibalism, competition and limited food availability represent the major threats to egg and larval survival. Patch quality assessment mechanisms enable females to lay eggs at sites where offspring survival is maximized. Oviposition-deterring semiochemicals tend to promote more even distribution of predators over prey patches.
Response of the polyphagous whitefly Bemisia tabaci B-biotype (Hemiptera: Aleyrodidae) to crop diversification – influence of multiple sensory stimuli on activity and fecundity
Authors: Bird T.L. , Krüger K.
Published: January 2006

A fundamental question concerning crop diversification is which mechanisms determine pest population size in polycultures compared to monocultures. It has been proposed that polyphagous insects experience a difficulty in decision-making when selecting food and oviposition sites in the presence of different host plants. This hypothesis was tested in the extremely polyphagous whitefly Bemisia tabaci (Gennadius) B-biotype, where behaviour (movement) and fecundity of females were compared in choice and no-choice experiments in the laboratory. Two parallel tests, one on different crops, including cucumber, bean and tomato, and one on different tomato cultivars, were conducted using both a mixture of crops and of tomato cultivars, as opposed to the same crop or cultivar respectively. Bemisia tabaci showed a distinct behavioural preference for cucumber when exposed to different crops simultaneously suggesting that B. tabaci has no difficulty in choosing a host plant, i.e. in making a decision, when one of the plants offered in the choice test is a high-ranking host plant. Conversely, when only low-ranking hosts of similar, but not identical, signatures were present, female whiteflies appeared to have difficulty in making a decision, resulting in increased movement and reduced fecundity. This is consistent with both the hypothesis that polyphagous insects have a problem selecting a host plant when given multiple choices and with the hierarchy threshold model, under which egg loads are lessened between periods of searching for better host plants. The study illustrates how insect behaviour can be affected by intercropping not only with different crops, but also with different cultivars of the same crop, thus potentially providing a simple and efficient way of reducing whitefly population build-up.
Critical review of health effects of soyabean phyto-oestrogens in post-menopausal women
Authors: Cassidy Aedin , Albertazzi Paola , Nielsen Inge Lise , Hall Wendy , Williamson Gary , Tetens Inge , Atkins Steve , Cross Heide , Manios Yannis , Wolk Alicja , Steiner Claudia , Branca Francesco
Published: January 2006

A consensus view of soyabean phyto-oestrogens in clinical interventions in post-menopausal women is presented that is based on data from the EU-funded project Phytohealth. The phyto-oestrogens, primarily genistein and daidzein, were given as soyabean-protein isolates, whole-soyabean foods or extracts, supplements or pure compounds. A comprehensive literature search was conducted with well-defined inclusion or exclusion criteria. For areas for which substantial research exists only placebo-controlled double-blind randomised controlled trials (RCT) conducted on healthy post-menopausal women were included. For emerging areas all available human studies in post-menopausal women were reviewed. In order to make cross comparisons between studies the doses of isoflavones were calculated as aglycone equivalents. There is a suggestion, but no conclusive evidence, that isoflavones from the sources studied so far have a beneficial effect on bone health. The consumption of whole-soyabean foods and soyabean-protein isolates has some beneficial effects on lipid markers of cardiovascular risk. The consumption of isolated isoflavones does not affect blood lipid levels or blood pressure, although it may improve endothelial function. For menopausal symptoms there is currently limited evidence that soyabean-protein isolates, soyabean foods or red-clover (Trifolium pratenseL.) extract are effective but soyabean isoflavone extracts may be effective in reducing hot flushes. There are too few RCT studies to reach conclusions on the effects of isoflavones on breast cancer, colon cancer, diabetes or cognitive function. The health benefits of soyabean phyto-oestrogens in healthy post-menopausal women are subtle and even some well-designed studies do not show protective effects. Future studies should focus on high-risk post-menopausal women, especially in the areas of diabetes, CVD, breast cancer and bone health.