bluuebunny/crossref_metadata_2025 huggingface dataset:
Association of folate intake with the occurrence of depressive episodes in middle-aged French men and women
Authors: Astorg Pierre , Couthouis Aline , de Courcy Geneviève Potier , Bertrais Sandrine , Arnault Nathalie , Meneton Pierre , Galan Pilar , Hercberg Serge
Published: December 2007

A low folate intake or a low folate status have been found to be associated with a higher frequency of depression in populations, but the existence and the direction of a causal link between folate intake or status and depression is still uncertain. The aim of this study was to seek the relation between the habitual folate intake in middle-aged men and women and the occurrence of depressive episodes. In a subsample of 1864 subjects (809 men and 1055 women) from the French SU.VI.MAX cohort, dietary habits have been measured at the beginning of the follow-up (six 24 h records) and declarations of antidepressant prescription, taken as markers of depressive episodes, have been recorded during the 8-year follow-up. No significant association was observed between folate intake and the risk of any depressive episode or of a single depressive episode during the follow-up, in both men and women. In contrast, the risk of experiencing recurrent depressive episodes (two or more) during the follow-up was strongly reduced in men with high folate intake (OR 0·25 (95 % CI 0·06, 0·98) for the highest tertilev.the lowest,Pfor trend 0·046). This association was not observed in women. These results suggest that a low folate intake may increase the risk of recurrent depression in men.
Lipid peroxidative stress and antioxidant defence status during ontogeny of rainbow trout (Oncorhynchus mykiss)
Authors: Fontagné Stéphanie , Lataillade Emilie , Brèque Janine , Kaushik Sadasivam
Published: December 2007

The objective of the present study was to characterise some important antioxidant enzymes and their relationships with retinoids and lipid peroxidation during rainbow trout (Oncorhynchus mykiss) early development. Eggs were incubated at 7°C until the swim-up stage whereupon fry were fed two semi-purified diets with 0 % (CO) and 8 % (OX) oxidised lipid respectively for 2 months at 17°C. The activities and gene expression of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) were determined as well as the levels of retinoids, F2-isoprostanes and lipid-soluble fluorescent products (LSFP) at various developmental stages. Only SOD had a detectable activity in embryos which increased during development and was linked with an increase of mitochondrial (SOD2) and cytosolic (SOD1) gene expression. SOD1 and SOD2 mRNA were more abundant in fry fed OX than in fry fed CO. CAT activity and gene expression also increased during development and were higher in fry fed OX compared with fry fed CO. Activity of Se-dependent GPX (Se-GPX) increased during development. The gene expression of cytosolic Se-GPX (GPX1) increased from hatching to 2-month-fed fry. Both phospholipid-hydroperoxide GPX and GPX1 genes were more expressed in fry fed OX than in fry fed CO. Retinoids decreased during development and, by 2 months, were lowered in fry fed OX compared with those fed CO. The levels of LSFP were higher in fry fed OX compared with fry fed CO. The present study demonstrates that antioxidant defence systems are active all through the development of rainbow trout and modulated by feeding oxidised lipid.
Response of cell cycle/stress-related protein expression and DNA damage upon treatment of CaCo2 cells with anthocyanins
Authors: Renis Marcella , Calandra Laura , Scifo Christian , Tomasello Barbara , Cardile Venera , Vanella Luca , Bei Roberto , Fauci Luca La , Galvano Fabio
Published: December 2007

Anthocyanins are a class of flavonoids, widely spread throughout the plant kingdom, exhibiting important antioxidant and anti-inflammatory actions as well as chemotherapeutic effects; nonetheless, little is known about the molecular mechanisms by which these activities are exerted. The present study is aimed at investigating molecular mechanisms involved in the chemotherapeutic effects induced by both cyanidin-3-O-β glucopyranoside (CY3G) and its aglycon form, cyanidin chloride (CY), in human colon cancer cells (CaCo2). The effect on cell growth, reactive oxygen species (ROS) formation and cell cycle/stress proteins modification, including ataxia teleangectasia mutated protein (ATM), p53, p21, 8-oxoguanine DNA glycosylase (OGG1), 70 kDa heat shock protein (HSP70) and topoisomerase IIβ, as well as on DNA fragmentation, was determined. CY and CY3G treatment affect cell growth and cell proliferation, this latter in a moderately dose-dependent way. Interestingly, ROS level is decreased by any concentration of CY and, only at the lowest concentration, by CY3G. Moreover, the two molecules exert their activities increasing ATM, topoisomerase II, HSP70 and p53 expression. The analysis of DNA fragmentation by Comet assay evidences: (1) a dose-dependent increase in DNA damage only after treatment with CY3G; (2) a more evident trend in the DNA fragmentation when the treatment is performed on agarose embedded cells (cellular atypical Comet); (3) a highly dose-dependent DNA fragmentation induced by CY when the treatment is carried out on agarose embedded naked DNA (acellular atypical Comet). The present findings substantiate a possible chemotherapeutic role of anthocyanins and suggest that CY and CY3G act on CaCo2 by different mechanisms, respectively, ROS-dependent and ROS-independent.
Effect of long-term selenium yeast intervention on activity and gene expression of antioxidant and xenobiotic metabolising enzymes in healthy elderly volunteers from the Danish Prevention of Cancer by Intervention by Selenium (PRECISE) Pilot Study
Authors: Ravn-Haren Gitte , Krath Britta N. , Overvad Kim , Cold Søren , Moesgaard Sven , Larsen Erik H. , Dragsted Lars O.
Published: December 2007

Numerous mechanisms have been proposed to explain the anti-carcinogenic effects of Se, among them altered carcinogen metabolism. We investigated the effect of Se supplementation on activities of glutathione peroxidase (GPX), glutathione reductase (GR) and glutathioneS-transferase (GST) in different blood compartments, and expression of selected phase 1 and phase 2 genes in leucocytes (GPX1,γ-glutamylcysteine ligasecatalytic subunit (GCLC), AP-1 transcription factorFos-related antigen 1(Fra1),NAD(P)H:quinone oxidoreductase(NQO1), andaryl hydrocarbon receptor repressor(AhRR)). Healthy elderly Danes (n105; age 71·3 (sd4·26) years; 36 % reporting use of multivitamin/mineral supplements) participated and were supplemented daily for 5 years with placebo, 100 μg, 200 μg or 300 μg Se as Se-enriched yeast (SelenoPrecise®). Blood samples were collected after 5 years of intervention. When all four groups were compared we found no effect of Se supplementation on plasma GPX or GR, on erythrocyte GPX, GR or GST, or on thrombocyte GR or GST. We found increased thrombocyte GPX activity at the two highest dosage levels in women only, but not in men. No effects onGPX1,NQO1orAhRRgene expression were found. When all Se-supplemented groups were pooled we found significant down regulation of the expression of some phase 2 genes (GCLC,Fra1). A significant increase inAhRRgene expression with smoking was found but was independent of Se supplementation. Down regulation of phase 2 genes could increase the risk of cancer. However, further studies are needed to establish whether the observed effect in leucocytes reflects a similar expression pattern in target tissues.
Effect of selenium and Ascaridia galli infection on antioxidant biomarkers in broiler chickens: a mathematical model for parasite reduction and host growth
Authors: Gabrashanska M. , Galvez-Morros M. , Teodorova S.E. , Ermidou-Pollet S. , Pollet S.
Published: December 2007

The activity of selenium-dependent glutathione peroxidase (GPX), liver concentration of vitamin E, and plasma and liver selenium levels were used for estimation of the antioxidant status of broiler chickens infected with Ascaridia galli. These biomarkers were recorded in an experiment covering 70 days p.i. At the same time the establishment rate of A. galli in chicken intestines, gain in the host body weight and chicken survival were studied. Broiler chickens (Cobb hybrids) were infected with 1450 embryonated A. galli eggs and treated with Sel-plex. A mathematical model was applied to determine the rate of nematode reduction and the relative rate of gain of host body weight, which are essential kinetic parameters of parasite–host interaction. The activity of GPX increased with both elevated selenium and reduced infection levels. The concentrations of selenium and vitamin E, and the GPX activity in the infected chickens demonstrated a similar pattern of change with time after day 30 p.i. The supplementation of the broilers with dietary selenium in the form of Sel-plex improved their antioxidant status. Increases by 29% in vitamin E concentration, 15% in GPX activity, and 22% in liver selenium concentration, respectively, were recorded in the infected and treated, compared to infected and untreated broilers.
Modification of gDNA extraction from soil for PCR designed for the routine examination of soil samples contaminated with Toxocara spp. eggs
Authors: Borecka A. , Gawor J.
Published: December 2007

A modification of gDNA extraction was developed for the polymerase chain reaction (PCR) technique, intended for the detection and differentiation of Toxocara spp. eggs in soil or sediments. Sand samples from sandpits confirmed as being contaminated with Toxocara spp. eggs by the flotation technique were analysed by PCR. The use of proteinase K made it possible to obtain genomic DNA from the sample without needing to isolate eggs using flotation or to inactivate PCR inhibitors present in the sand. Specific primers in the PCR reaction allowed discrimination between T. canis and T. cati eggs. The modification simplified the procedure, thanks to eliminating the step of gDNA isolation from eggs, which is both laborious and difficult.
Influence of the transmission function on a simulated pathogen spread within a population
Authors: HOCH T. , FOURICHON C. , VIET A.-F. , SEEGERS H.
Published: December 2007

The mathematical function for the horizontal transmission of a pathogen is a driving force of epidemiological models. This paper aims at studying the influence of different transmission functions on a simulated pathogen spread. These functions were chosen in the literature and their biological relevance is discussed. A theoretical SIR (Susceptible–Infectious–Recovered) model was used to study the effect of the function used on simulated results. With a constant total population size, different equilibrium values for the number of infectious (NI) were reached, depending on the transmission function used. With an increasing population size, the transmission functions could be assimilated to either density-dependent (DD), where an equilibrium was obtained, or frequency-dependent (FD), with an exponential increase in NI. An analytical study corroborated the simulated results. As a conclusion, the choice between the different transmission functions, particularly between DD and FD, must be carefully considered for a varying population size.
Jack Sepoy and the Dervishes: Islam and the Indian Soldier in Princely India
Authors: GREEN NILE
Published: December 2007

Like other Britons in colonial India, Sir William Sleeman had a poor opinion of the traditional holy men who still formed an important part of Indian society in the nineteenth century. Reflecting his writings on the suppression of the Thugs that would make him famous, Sleeman declared that, “There is hardly any species of crime that is not throughout India perpetrated by men in the disguise of these religious mendicants; and almost all such mendicants are really men in disguise”.1 None of these holy men were considered more dubious – more superstitious and reactionary – than the dervishes and faqīrs. In popular Indian usage the terms darwīsh and faqīr referred to a class of Muslim holy men who were considered to possess a range of miraculous powers, powers which served to demonstrate their proximity to God; and so in turn to underwrite their considerable authority.2 For many British officials, it was this authority that stood at the heart of what they saw as the faqīr problem. As the rumours that surrounded the various ‘mutinies’ of the nineteenth century demonstrate, faqīr s were seen as the perpetual ringleaders of rebellion and sedition. Nowhere were these concerns more insistent than in the circles of India's colonial armies, which more than any other aspect of colonial society relied on loyalty to a formalised and rational chain of command. Yet in spite (and in some ways because) of these fears, the commanders of the various armies under British command in India were anxious to demonstrate their respect for the autonomy of the religious rights of the Indian soldier. Through the course of the nineteenth and early twentieth century, the Islam of ‘Jack Sepoy’ or the Indian soldier fell in between this tension of covert suspicion and official respect, and in different ways the careers of a series of Muslim holy men attached to the Muslim soldiers were shaped by this tension. Over the following pages, this essay examines the careers of three faqīr s connected to the Hyderabad Contingent, the army under British command in the nominally independent princely state of Hyderabad in South India, better known as the Nizam's State. Looking out from this princely corner of Britain's ‘informal empire’, the essay uses a number of forgotten small-town texts in Urdu to begin to reconstruct the religious history of the Indian soldier from the inside, as it were, and so to create an ethnohistory of Islam in the colonial armies of the British Empire.3
Simplicity and belief
Authors: Treib Marc
Published: December 2007

There seems to be little question that we live in an age of complexity, perhaps undue complexity. The interrelation of almost all the people all the time – at least those with internet access – the pressures of urbanisation, natural resource depletion, increasing traffic and pollution, and our ability to be anywhere at any time electronically have led to a rather complex living mode. Architects, heeding the call, have produced an architecture of corresponding complexity. Falling to architectural fashion trends, market pressures, and the surge of corporate capitalism, architects now give their clients just what they want, or what they themselves want to give them. There was a time when architectural form expressed some relation to reason, but that dated notion seems to be in little evidence today.
Haut und Kollagenosen
Authors: Trüeb
Published: December 2007

Dermatologie und Rheumatologie haben gemeinsam, dass viele rheumatische Krankheiten sich augenfällig an der Haut abspielen. Da die Haut der direkten klinischen Untersuchung und Biopsie zugänglich ist, wissen die Rheumatologen den Rat des klinisch und pathologisch-morphologisch erfahrenen Dermatologen einzuholen. Obwohl die Medizin zunehmend zum organbezogenen Partikularismus des Spezialistentums tendiert, bemüht sich die ihrem Wesen nach interdisziplinär angelegte Dermatologie um eine fächerübergreifende Kommunikation. Durch die Zusammenfassung und Klassifikation autoimmun bedingter, chronisch-entzündlicher Krankheiten unter den Kollagenosen gelang schon früh der synoptischen Betrachtungsweise autoimmunologisch bedingter, chronisch-entzündlicher Systemkrankheiten ein entscheidender Fortschritt. Diese Krankheiten haben einen entzündlichen Gewebeschaden, Neigung zu Chronizität mit akuten Exazerbationen und Ansprechen auf hochdosierte Kortikosteroide und/oder Immunsuppressiva gemeinsam. Sie umfassen: Lupus erythematodes, Dermatomyositis, Systemsklerose, ihre Kombination (Mischkollagenose) und die Systemvaskulitiden. Ihre Heterogenität schlägt sich als Vielfalt der klinischen Erscheinungsbilder nieder, auch an der Haut. Der Haut kommt dabei eine wichtige Markerfunktion sowohl für die Diagnose als auch für die Prognose zu. Speziell bei den limitierten Formen entzündlich-rheumatischer Krankheiten stellt sich die grundsätzliche Frage nach der Prognose und der damit verbundenen Aggressivität einer einzuschlagenden Therapie. Als Orientierungshilfe hat sich das Konzept der Subklassifizierung entsprechender Krankheitsbilder und Entitäten durchgesetzt, bei der eine Korrelation zwischen klinischer Manifestationsform, insbesondere an der Haut, immunserologischem Profil, Verlauf und Prognose gelingt.
Chemical characteristics of fulvic acids from Arctic surface waters: Microbial contributions and photochemical transformations
Authors: Cory Rose M. , McKnight Diane M. , Chin Yu‐Ping , Miller Penney , Jaros Chris L.
Published: December 2007

Dissolved organic matter (DOM) originating from the extensive Arctic tundra is an important source of organic material to the Arctic Ocean. Chemical characteristics of whole water dissolved organic matter (DOM) and the fulvic acid fraction of DOM were studied from nine surface waters in the Arctic region of Alaska to gain insight into the extent of microbial and photochemical transformation of this DOM. All the fulvic acids had a strong terrestrial/higher plant signature, with uniformly depleted δ13C values of −28‰, and low fluorescence indices around 1.3. Several of the measured chemical characteristics of the Arctic fulvic acids were related to water residence time, a measure of environmental exposure to sunlight and microbial activity. For example, fulvic acids from Arctic streams had higher aromatic contents, higher specific absorbance values, lower nitrogen content, lower amino acid–like fluorescence and were more depleted in δ15N relative to fulvic acids isolated from lake and coastal surface waters. The differences in the nitrogen signature between the lake and coastal fulvic acids compared to the stream fulvic acids indicated that microbial contributions to the fulvic acid pool increased with increasing water residence time. The photo‐lability of the fulvic acids was positively correlated with water residence time, suggesting that the fulvic acids isolated from source waters with larger water residence times (i.e., lakes and coastal waters) have experienced greater photochemical degradation than the stream fulvic acids. In addition, many of the initial differences in fulvic acid chemical characteristics across the gradient of water residence times were consistent with changes observed in fulvic acid photolysis experiments. Taken together, results from this study suggest that photochemical processes predominantly control the chemical character of fulvic acids in Arctic surface waters. Our findings show that hydrologic transport in addition to biogeochemical alteration of the organic matter must be considered in order to predict the ultimate fate of Arctic DOM.
Comparison of pressure‐saturation characteristics derived from computed tomography and lattice Boltzmann simulations
Authors: Schaap Marcel G. , Porter Mark L. , Christensen Britt S. B. , Wildenschild Dorthe
Published: December 2007

A Shan‐Chen–type multiphase lattice Boltzmann (LB) model was applied to observed computed microtomography data from water‐air and water‐Soltrol displacement experiments in a glass bead porous medium. Analysis of the Bond, Reynolds, and Capillary numbers for these systems showed that capillary forces were dominant removing the need to model viscous, gravitational, and density effects. A numerical parameterization of the LB model yielded lattice surface tension and contact angle, and appropriate pressure boundary conditions. Two scaling relations provided a link between lattice pressure and physical pressure and lattice time and physical time. Results showed that there was a good match between measured and simulated pressure‐saturation data for the water‐air system, but that there were large differences between the simulations and observations for the water‐Soltrol system. The discrepancies for the water‐Soltrol system were probably due to inconsistencies between experimental conditions and simulated conditions such as nonzero contact angle in the experiments. Analysis of saturation profiles indicated increasing saturation near the wetting boundary and decreasing saturations near the nonwetting boundary. We attribute these saturation transitions to pore‐neck and percolation effects. While computationally intensive, results of this study were very encouraging for the application of LB simulations to microscale interfacial phenomena. Future studies will carry out a further validation in terms of interfacial areas, contact lines, and fluid distributions.
On colloid retention in saturated porous media in the presence of energy barriers: The failure of α, and opportunities to predict η
Authors: Johnson William P. , Tong Meiping , Li Xiqing
Published: December 2007

This contribution reviews recent findings that illuminate the processes governing colloid retention in porous media under environmentally relevant conditions. In the environment, colloids act as conveyors of contaminants, or even as contaminants themselves; however, despite decades of research, we are unable to accurately predict the retention of colloids in granular aquifer media under environmental conditions, where repulsion exists between colloids and surfaces. This failure cannot be blamed solely on the complexities of the subsurface, since colloid filtration theory (CFT) works well in the absence of colloid‐collector repulsion despite its idealization of porous media as consisting of spherical grains completely surrounded by fluid envelopes. Rather, the failure of CFT stems from failure to incorporate the correct mechanisms of retention when repulsion exists. Recent observations implicate wedging in grain‐to‐grain contacts and retention in secondary energy minima as dominant mechanisms of colloid retention in the presence of an energy barrier. Mechanistic simulations in unit cells containing grain‐to‐grain contacts corroborate these mechanisms of colloid retention. The resulting concept for colloid retention in the presence of an energy barrier involves translation of colloids across the collector surfaces until they become wedged within grain‐to‐grain contacts, or are retained via secondary energy minima (without attachment) in zones where the balance of fluid drag, diffusion, gravitational, and colloid‐collector interaction forces allow retention. The above findings highlight the pore domain geometry as a dominant governor of colloid retention in so far as the geometry gives rise to grain‐to‐grain contacts and zones of relatively low fluid drag.
Rheology of ɛ‐iron up to 19 GPa and 600 K in the D‐DIA
Authors: Nishiyama Norimasa , Wang Yanbin , Rivers Mark L. , Sutton Steve R. , Cookson David
Published: December 2007

Stress‐strain curves, i.e., relations between the differential stress and macroscopic sample strain, of polycrystalline ɛ‐iron have been obtained at pressures of 17(±1) GPa, three different temperatures (600, 400, and 300 K), and various strain rates between 3.8 × 10−6 and 2.3 × 10−5 s−1 using the deformation‐DIA coupled with monochromatic X‐rays. Five independent stress‐strain curves were obtained on axial shortening and the sample exhibited ductile behavior in all. Above 4% axial strain, sample stresses reach saturation and the sample exhibited steady‐state deformation. Stress exponents at temperatures of 400 and 600 K were determined to be ∼31 and ∼7, respectively. These results indicate that ɛ‐iron deforms in plasticity regime below 400 K and that the dominant deformation mechanism at 600 K may be low temperature power‐law creep. The overall deformation behavior for ɛ‐iron is consistent with that of zinc, suggesting that the deformation mechanism map of ɛ‐iron resembles those of other hexagonal metals.
Tropical cyclone energy dispersion under vertical shears
Authors: Ge Xuyang , Li Tim , Zhou Xiaqiong
Published: December 2007

Tropical cyclone Rossby wave energy dispersion under easterly and westerly vertical shears is investigated in a baroclinic model. In a resting environment, the model simulates a Rossby wave train that has a baroclinic structure with alternating cyclonic‐anticyclonic‐cyclonic (anticyclonic‐cyclonic‐anticyclonic) circulations in the lower (upper) troposphere. A significant asymmetry appears in the wave train development under easterly and westerly vertical shears, that is, an easterly (westerly) shear confines the maximum amplitude of the wave train primarily to the lower (upper) level. It is proposed that the vertical wind shear may impact the Rossby wave train development through both the barotropic‐baroclinic mode coupling and the modulation of the group velocity by the mean flow through a “Doppler shift effect”. Additional experiments with uniform westerly and easterly mean flows confirm the hypothesis. The enhancement of the Rossby wave train in the lower level by the easterly shear may have an important implication for understanding the tropical cyclogenesis and the origin of the synoptic wave trains in the western North Pacific.
Changes in coral-associated microbial communities during a bleaching event
Authors: Bourne David , Iida Yuki , Uthicke Sven , Smith-Keune Carolyn
Published: December 2007

Environmental stressors such as increased sea surface temperatures are well-known for contributing to coral bleaching; however, the effect of increased temperatures and subsequent bleaching on coral-associated microbial communities is poorly understood. Colonies of the hard coral Acropora millepora were tagged on a reef flat off Magnetic Island (Great Barrier Reef) and surveyed over 2.5 years, which included a severe bleaching event in January/February 2002. Daily average water temperatures exceeded the previous 10-year average by more than 1 °C for extended periods with field-based visual surveys recording all tagged colonies displaying signs of bleaching. During the bleaching period, direct counts of coral zooxanthellae densities decreased by ∼64%, before recovery to pre-bleaching levels after the thermal stress event. A subset of three tagged coral colonies were sampled through the bleaching event and changes in the microbial community elucidated. Denaturing gradient gel electrophoresis (DGGE) analysis demonstrated conserved bacterial banding profiles between the three coral colonies, confirming previous studies highlighting specific microbial associations. As coral colonies bleached, the microbial community shifted and redundancy analysis (RDA) of DGGE banding patterns revealed a correlation of increasing temperature with the appearance of Vibrio-affiliated sequences. Interestingly, this shift to a Vibrio-dominated community commenced prior to visual signs of bleaching. Clone libraries hybridized with Vibrio-specific oligonucleotide probes confirmed an increase in the fraction of Vibrio-affiliated clones during the bleaching period. Post bleaching, the coral microbial associations again shifted, returning to a profile similar to the fingerprints prior to bleaching. This provided further evidence for corals selecting and shaping their microbial partners. For non-bleached samples, a close association with Spongiobacter-related sequences were revealed by both clone libraries and DGGE profiling. Despite Vibrio species being previously implicated in bleaching of specific coral species, it is unsure if the relative increase in retrieved Vibrio sequences is due to bacterial infection or an opportunistic response to compromised health and changing environmental parameters of the coral host. This study provides the first molecular-based study demonstrating changes in coral-associated bacterial assemblages during a bleaching event on a natural reef system.
Bacteria are not the primary cause of bleaching in the Mediterranean coral Oculina patagonica
Authors: Ainsworth T D , Fine M , Roff G , Hoegh-Guldberg O
Published: December 2007

Coral bleaching occurs when the endosymbiosis between corals and their symbionts disintegrates during stress. Mass coral bleaching events have increased over the past 20 years and are directly correlated with periods of warm sea temperatures. However, some hypotheses have suggested that reef-building corals bleach due to infection by bacterial pathogens. The ‘Bacterial Bleaching’ hypothesis is based on laboratory studies of the Mediterranean invading coral, Oculina patagonica, and has further generated conclusions such as the coral probiotic hypothesis and coral hologenome theory of evolution. We aimed to investigate the natural microbial ecology of O. patagonica during the annual bleaching using fluorescence in situ hybridization to map bacterial populations within the coral tissue layers, and found that the coral bleaches on the temperate rocky reefs of the Israeli coastline without the presence of Vibrio shiloi or bacterial penetration of its tissue layers. Bacterial communities were found associated with the endolithic layer of bleached coral regions, and a community dominance shift from an apparent cyanobacterial-dominated endolithic layer to an algal-dominated layer was found in bleached coral samples. While bacterial communities certainly play important roles in coral stasis and health, we suggest environmental stressors, such as those documented with reef-building corals, are the primary triggers leading to bleaching of O. patagonica and suggest that bacterial involvement in patterns of bleaching is that of opportunistic colonization.
Observations of dust acoustic waves driven at high frequencies: Finite dust temperature effects and wave interference
Authors: Thomas Edward , Fisher Ross , Merlino Robert L.
Published: December 2007

An experiment has been performed to study the behavior of dust acoustic waves driven at high frequencies (f>100Hz), extending the range of previous work. In this study, two previously unreported phenomena are observed—interference effects between naturally excited dust acoustic waves and driven dust acoustic waves, and the observation of finite dust temperature effects on the dispersion relation.
Electrical conduction in undoped ultrananocrystalline diamond thin films and its dependence on chemical composition and crystalline structure
Authors: Correa Eric J. , Wu Yan , Wen Jian-Guo , Chandrasekharan Ramesh , Shannon Mark A.
Published: December 2007

The electrical conduction behavior of undoped ultrananocrystalline diamond (UNCD) and its dependence on deposition temperature and chemical structure are presented. UNCD films were grown using a microwave plasma-enhanced chemical vapor deposition technique at deposition temperatures of 400 °C and 800 °C. The chemical structure of the UNCD films is characterized with several tools including: Elastic recoil detection analysis, Fourier transform infrared spectroscopy, electron energy loss spectroscopy, Raman spectroscopy, and environmental scanning electron microscope. The results show a higher content of sp2-bonded carbon for the 800 °C deposition samples (∼65%) in comparison with the 400 °C samples (∼38%). In both kinds of films, the hydrocarbon bonds have the saturated sp3 structures, while there is lower hydrogen content in the 800 °C samples (∼8%) than in the 400 °C samples (∼10%). For conduction properties, experiments are conducted using a probe station and conductive-atomic force microscopy. Experimental data show that the samples deposited at 800 °C are several orders of magnitude more conductive than the 400 °C samples. The conduction occurs primarily along the grain boundary for both types of samples. The conductivity of both types of films also shows field dependent nonlinear behavior. Both the Poole–Frenkel models and single and overlapping Coulombic potential models show that the conduction is directly correlated with the sp2 bond carbon density, and the role of the hydrocarbon bonds in the conduction path is formed by the network of the sp2 bonded carbon.
Ab initio design of coherent thermal sources
Authors: Drevillon Jérémie , Ben-Abdallah Philippe
Published: December 2007

Emission of thermal light from a hot body has been considered for a long time as broadband and quasi-isotropic. Today, we know that this paradigm is wrong and it has been shown that many micro- and nanostructured materials are able to radiate in narrow spectral bands and around specific directions of space. However, so far, only heuristic strategies based on trial and error have been followed for engineering such sources. Here, we present a general method for the ab initio design of coherent thermal sources by using only the first principles of optics. Our results pave the way toward the inverse design of new composite emitting structures for high performance applications in optics.
Theory of spin-dependent tunneling current in ferromagnetic metal–oxide–silicon structures
Authors: Serdouk S. , Hayn R. , Autran J.-L.
Published: December 2007

A theory is presented to calculate the spin-dependent tunneling current of ferromagnetic metal–oxide–silicon junctions. It is based on the theory of the tunneling process which was developed by Bardeen, and takes into account the specific properties of the barrier, as well as the material specifics on both sides of the barrier. It is applied to calculate the current–voltage characteristics of the spin-up and spin-down currents of the elemental ferromagnetic metals (Fe, Co, and Ni) connected to Si by a tunneling barrier.
Phase-locked scanning interferometer for frequency stabilization of multiple lasers
Authors: Tonyushkin Alexei A. , Light Adam D. , Di Rosa Michael D.
Published: December 2007

We report a simple scheme for stabilizing and tuning the length of a conventional piezo-driven optical cavity against the resonant transmission of a master laser. In contrast with other schemes, we drive the piezo at its mechanical resonance of 5kHz over an amplitude equivalent to one free spectral range and use a feedback circuit that incorporates phase-sensitive detection of the master-laser transmission. The bandwidth of our cavity-lock circuit is limited only by the resonance frequency of the cavity piezo and is 1.4kHz. The stabilized mean cavity length reaches in 30 s a minimum Allan deviation of ∼10kHz (a length stability of 20 parts per trillion) equaling that of the polarization-stabilized He–Ne we use as our master laser. Here, we investigate the mechanical characteristics of the cavity, describe the lock circuit and its measured performance, and provide simple analytical relations between the phase-sensitive signal and cavity displacement. Our setup economizes the cost and amount of equipment necessary for stabilizing multiple continuous-wave lasers operating at different wavelengths.
Design and implementation of an efficient acoustically levitated drop reactor for in stillo measurements
Authors: Field Christopher R. , Scheeline Alexander
Published: December 2007

We present the details necessary for building an efficient acoustic drop levitator with reduced electrical power consumption and greater drop stability compared to previous designs. The system is optimized so that the levitated drop may be used as a chemical reactor. By introducing a temperature, pressure, and relative humidity sensor for feedback control of a linear actuator for adjusting resonator length, we have built a completely automated system capable of continuous levitation for extended periods of time. The result is a system capable of portable operation and interfacing with a variety of detection instrumentation for in stillo (in drop) measurements.
Meyer-Neldel rule in ZnO
Authors: Schmidt Heidemarie , Wiebe Maria , Dittes Beatrice , Grundmann Marius
Published: December 2007

Seventy years ago Meyer and Neldel investigated four polycrystalline n-type conducting ZnO rods [W. Meyer and H. Neldel, Z. Tech. Phys. (Leipzig) 12, 588 (1937)]. The specific conductivity increased exponentially with temperature. A linear relationship between the thermal activation energy for the specific conductivity and the logarithm of the prefactor was observed. Since then thermally activated processes revealing this behavior are said to follow the Meyer-Neldel (MN) rule. We show that the emission of charge carriers from deep electron traps in ZnO follows the MN rule with the isokinetic temperature amounting to 226±4K.
Structural templating as a route to improved photovoltaic performance in copper phthalocyanine/fullerene (C60) heterojunctions
Authors: Sullivan P. , Jones T. S. , Ferguson A. J. , Heutz S.
Published: December 2007

We have developed a method to improve the short circuit current density in copper phthalocyanine (CuPc)/fullerene (C60) organic solar cells by ∼60% by modifying the CuPc crystal orientation through use of a molecular interlayer to maximize charge transport in the direction between the two electrodes. Powder x-ray diffraction and electronic absorption spectroscopy show that a thin 3,4,9,10-perylenetetracarboxylic dianhydride interlayer before CuPc growth templates the CuPc film structure, forcing the molecules to lie flat with respect to the substrate surface, although the intrastack orientation is unaffected. This modified stacking configuration facilitates charge transport and improves charge collection.
Scanning x-ray microdiffraction of optically manipulated liposomes
Authors: Cojoc D. , Ferrari E. , Garbin V. , Di Fabrizio E. , Amenitsch H. , Rappolt M. , Sartori B. , Laggner P. , Burghammer M. , Riekel C.
Published: December 2007

We show optical tweezers manipulation of individual micron-sized samples investigating at the same time their inner nanostructure by synchrotron diffraction experiments. The validity of this technique is demonstrated for clusters of multilamellar liposomes trapped in single and multiple positions in the optical path of a microfocused x-ray beam and analyzed in a microscanning mode. The signal to background ratio of the first order peak shows that single liposome measurements are feasible. Multiple trapping by means of diffractive optical elements is demonstrated as an effective manipulation tool for future x-ray diffraction studies of the interaction between different sample entities.
Decay of zone-center phonons in AlN with A1, E1, and E2 symmetries
Authors: Pandit P. , Song D. Y. , Holtz M.
Published: December 2007

Raman studies are reported for the A1(TO), E1(TO), E22, and A1(LO) symmetry phonons of AlN from 20to375K. By applying anharmonic decay theory to the observed temperature dependences of the phonon energies and linewidths, we determine the phonon decay mechanisms of these zone-center vibrations. Thermal expansion is taken into account using published temperature-dependent coefficients. The A1(TO), E1(TO), and E22 vibrations are described by symmetric two-phonon decay. The A1(LO) band is interpreted by an asymmetric two-phonon decay. Phonon lifetimes are obtained based on the observed linewidths and the dependence allows us to estimate the impurity-related phonon lifetime for each vibration. The latter ranges from 2.9to9.1ps.
Highly efficient p-i-n white organic light emitting devices with tandem structure
Authors: Ho Meng-Huan , Chen Teng-Ming , Yeh Pu-Cheng , Hwang Shiao-Wen , Chen Chin H.
Published: December 2007

Highly efficient tandem p-i-n white organic light emitting devices have been fabricated. Utilizing an optical transparent bilayer with doped organic p-n junction that consists of 4,7-diphenyl-1,10-phenanthroline: 2% cesium carbonate (Cs2CO3)∕N,N′-bis(1-naphthyl)-N,N′-diphenyl-1,1′-biphenyl-4,4′-diamine: 50% v/v tungsten oxide (WO3) as the connecting layer, the tandem p-i-n white device achieved an electroluminescence efficiency of 23.9cd∕A and a power efficiency of 7.8lm∕W at 20mA∕cm2 with a Commission Internationale de l’Eclairage coordinates of (0.30, 0.43). The electroluminescent color of this tandem p-i-n white organic light-emitting diode device will not change significantly with respect to drive current variation and forward viewing angle.
Broadband and time-resolved absorption spectroscopy with light emitting diodes: Application to etching plasma monitoring
Authors: Cunge G. , Vempaire D. , Touzeau M. , Sadeghi N.
Published: December 2007

Broad band absorption spectroscopy is widely used to measure the concentration of radicals, which is important to understand the physical chemistry of many plasmas. It is possible to increase the sensitivity of this technique and to perform time-resolved measurement by using light emitting diodes (LEDs) as a light source. The method is applied to detect CF2 radicals and Cl2 molecules in high density plasmas. The detection limit over 10ms integration time is as low as 3mTorr of Cl2. We conclude that the absorption spectroscopy with LEDs opens possibilities for precise process control and fundamental analysis of reactive media.
Study of anode work function modified by self-assembled monolayers on pentacene/fullerene organic solar cells
Authors: Tseng Chung-Ting , Cheng Yu-Hung , Lee Ming-Chang M. , Han Chien-Chung , Cheng Chien-Hong , Tao Yu-Tai
Published: December 2007

The authors investigated the anode work function modified by series of self-assembled monolayers comprising alkanethiols and perfluorinated alkanethiols with different alkyl lengths on pentacene/fullerene thin-film organic solar cells. Via selecting different types of self-assembled molecules, the anode work function can be tailored for modifying the interfacial barrier. The measured open-circuit voltages indicated reduced anode work function that tends to form Schottky contact. The maximal open-circuit voltage and short-circuit current were measured to be 0.4V and 17.7mA∕cm2, respectively, in the case of anode work function modified by perfluorinated alkanethiols. The power conversion efficiency is 2.24%.
Re-visiting the CLAW hypothesis
Authors: Vallina S. M. , Simó R.
Published: December 2007

Environmental context. Over the last twenty years, large and continued research efforts have been invested in deciphering whether oceanic plankton contribute to the regulation of climate by the production and release of cloud-seeding atmospheric sulfur. Our recent research using globally spread observations and satellite-derived data suggest that biogenic sulfur from the oceans represents a major source of cloud-forming aerosols over much of the pristine southern hemisphere oceans. These climate-cooling sulfur emissions respond positively to incoming solar radiation over seasonal cycles, but show a weak response to anthropogenic global warming foreseen for the current century.
The iron CLAW
Authors: Harvey Mike
Published: December 2007

Environmental context. A ‘climate stabilising’ feedback system known as the CLAW hypothesis, which involves the phytoplankton driven influence on cloud reflectivity through the cycling of sulfur was proposed ~20 years ago, and because of its complexity, it remains unproven today. Since the CLAW proposal, experiments that have added iron to the ocean have proven that iron can significantly limit phytoplankton productivity and can also affect the marine sulfur cycle in a complex manner. Because of a range of possible feedbacks between iron, sulfur and climate, it is likely that future advances in understanding the CLAW hypothesis will require a comprehensive process-based description that can be tested in fully coupled earth-system models.
Sea-salt particles and the CLAW hypothesis
Authors: Smith Michael H.
Published: December 2007

Environmental context. When proposing that dimethyl sulfide (DMS) releases from phytoplankton had a role in regulating the global climate, the potential parallel influences of sea spray aerosols on climate were largely disregarded. Over the intervening 20 years, scientific studies have clearly demonstrated a substantial role for sea spray particles in modifying cloud properties and influencing global sulfur cycling, diminishing the significance of the DMS-based CLAW mechanism.
Where to now? A synthesis of current views of the CLAW hypothesis
Authors: Cainey Jill M. , Sievering Herman , Ayers Greg P.
Published: December 2007

Abstract. The CLAW hypothesis was published 20 years ago, building on suggestions that the sulfur cycle provided a natural feedback mechanism whereby plankton in the ocean had a role in modifying climate by providing the precursors for cloud condensation nuclei, which leads to the formation of high albedo clouds.
In this issue, the 10 preceding articles represent the opinions of several leading scientists working on various aspects of the CLAW hypothesis and here we synthesise these varied opinions to answer the questions: Does the CLAW hypothesis operate as described in the original 1987 publication? and What steps and advances are needed to better understand CLAW and resolve any outstanding areas of difficulty?
Depression, social support and adherence to highly active antiretroviral therapy in people living with HIV/AIDS
Authors: Gibbie Tania , Hay Margaret , Hutchison Chris W. , Mijch Anne
Published: December 2007

Background: The present study investigated the prevalence of depression in HIV-positive individuals and its association with adherence to highly active antiretroviral therapy (HAART). Methods: HIV-positive (n = 80) and HIV-negative (n = 20) participants were assessed for depression and adherence via clinical interview and self-reporting. Results: Fourteen percent of the HIV-seropositive group met the criteria for current mood disorder compared with 5% of controls. Similarly, 39% of the HIV-seropositive participants met the criteria for a past major depressive episode compared with 15% of controls. Non-adherence to HAART was reported by 30.5% of those prescribed HAART and was significantly associated with living alone and relationship status. Conclusions: The present study found compromised psychological health in people living with HIV infection. It is recommended that health professionals continue to screen for depression, relationship status and living situation to ensure adherence to HAART.
Aboriginal women's stories of sexually transmissible infection transmission and condom use in remote central Australia
Authors: Stark Astrid M. , Hope Alex
Published: December 2007

Background: Sexually transmissible infection (STI) rates are persistently high in central Australia, creating conditions for a potential HIV pandemic in the area. There is a shortage of qualitative research examining the underlying factors affecting STI transmission in this region. The present study investigates Aboriginal women’s current levels of knowledge regarding STI and their transmission, perception of risk for STI, patterns of condom use, access to condoms and experiences of condom negotiation with their partners. It also explores the sociocultural context of their sexual health. Methods: The present study used qualitative methods with a semistructured questionnaire. Twenty-four women aged 18–35 years from one remote central-Australian Aboriginal community were recruited. Results: The results revealed poor understandings of STI transmission, limited access to condoms and low levels of condom use despite a high perception of risk to STI. They also identified specific issues facing these women regarding the sociocultural context of their condom use, their access to condoms and the transmission of STI. The perceived effects of alcohol abuse, infidelity, sexual assault and shame on the acquisition of STI were significant issues for the women. Conclusion: This research has identified an urgent need for further qualitative research into the sociocultural factors that facilitate the spread of STI among Aboriginal people of remote central Australia. Implications include the need to increase their knowledge regarding STI and STI transmission, to increase women’s access to condoms and to incorporate the teaching of skills to deal with sexual assault and violence into sexual-health education.