bluuebunny/crossref_metadata_2025 huggingface dataset:
Fish response to modified flow regimes in regulated rivers: research methods, effects and opportunities
Authors: Murchie K. J. , Hair K. P. E. , Pullen C. E. , Redpath T. D. , Stephens H. R. , Cooke S. J.
Published: February 2008

Globally, rivers are increasingly being subjected to various levels of physical alteration and river regulation to provide humans with services such as hydropower, freshwater, flood control, irrigation and recreation. Although river regulation plays an important role in modern society, there are potential consequences which may negatively affect fish and fish habitat. While much effort has been expended examining the response of fish to fluctuating flow regimes in different systems, there has been little in the way of a comprehensive synthesis. In an effort to better understand the effects of river regulation on fish and fish habitat, we conducted a systematic review of available literature with three goals: (1) summarize the various research methodologies used by regulated river researchers, (2) summarize the effects found on fish and fish habitat and (3) identify opportunities for future research. The results of the synthesis indicate that a wide variety of methodologies are being employed to study regulated river science, yet there is a gap in incorporating methodologies that examine effects on fish at a cellular level or those techniques that are interdisciplinary (e.g. behaviour and physiology). There is a clear consensus that modified flow regimes in regulated rivers are affecting fish and fish habitat, but the severity and direction of the response varies widely. Future study designs should include methods that target all biological levels of fish response, and in which detailed statistical analyses can be performed. There is also a need for more rigorous study designs including the use of appropriate controls and replicates. Data on physical variables that co‐vary with flow should be collected and examined to add explanatory power to the results. Increased multi‐stakeholder collaborations provide the greatest promise of balancing ecological concerns with economic needs. Copyright © 2008 John Wiley & Sons, Ltd.
Interfacial studies of Al2O3 deposited on 4H‐SiC(0001)
Authors: Diplas Spyros , Avice Marc , Thøgersen Annett , Christensen Jens S. , Grossner Ulrike , Svensson Bengt G. , Nilsen Ola , Fjellvåg Helmer , Hinder Steve , Watts John F.
Published: February 2008

Al2O3 films deposited on 4H‐SiC(0001) by atomic layer deposition (ALD) were characterized by XPS, and high‐resolution transmission electron microscopy (HRTEM). The effect of medium and high temperature (873, 1273 K) annealing on samples with oxide thicknesses of 5–8 and 100–120 nm was studied. XPS indicated the presence of a thin (∼1 nm) SiOx layer on the as‐grown samples which increased to ∼3 nm after annealing above crystallization temperature (1273 K) in Ar atmosphere. Upon annealing the stoichiometry of the interfacial oxide approaches that of SiO2. HRTEM showed that the thickness of the interfacial oxide formed after annealing at 1273 K was not uniform. No significant increase in the thickness of the interfacial oxide, was observed after annealing at 873 K in a N2 (90%)/H2 (10%) atmosphere. Copyright © 2008 John Wiley & Sons, Ltd.
Applications of poly(3,4‐ethylenedioxythiophene) doped with poly(styrene sulfonic acid) transistors in chemical and biological sensors
Authors: Nikolou Maria , Malliaras George G.
Published: February 2008

The application of transistors based on poly(3,4‐ethylenedioxythiophene) doped with poly(styrene sulfonic acid) (PEDOT:PSS) in chemical and biological sensing is reviewed. These devices offer enormous potential for facile processing of small, portable, and inexpensive sensors ideally suited for point‐of‐care analysis. They can be used to detect a wide range of analytes for a variety of possible applications in fields such as health care (medical diagnostics), environmental monitoring (airborne chemicals, water contamination, etc.), and food industry (smart packaging). Organic transistors are excellent candidates to act as transducers because they have the ability to translate chemical and biological signals into electronic signals with high sensitivity. Furthermore, fuctionalization of PEDOT:PSS films with a chemical or biological receptor can lead to high specificity. The advantages of using PEDOT:PSS transistors are described, and applications are presented for sensing analytes in both gaseous and aqueous environments. © 2008 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 8: 13–22; 2008: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20133
Biochemical and genetic bases of dehalorespiration
Authors: Futagami Taiki , Goto Masatoshi , Furukawa Kensuke
Published: February 2008

Some anaerobic bacteria can efficiently eliminate one or more halide atoms from halogenated compounds such as chlorophenols and chloroethenes through reductive dehalogenation. During this process, the bacteria utilize halogenated compounds as the terminal electron acceptors in their anaerobic respiration, called dehalorespiration, to yield energy for growth. Currently the genera of Desulfitobacterium and Dehalococcoides occupy the major part of the dehalorespiring isolates. The former can acquire energy not only by dehalorespiration but also by other respirations utilizing organic compounds and metals. In sharp contrast, the latter is specialized in dehalorespiration and plays a crucial role in the detoxification of chlorinated compounds in nature. From these bacteria, various reductive dehalogenases, which catalyze the dehalogenation reaction, were purified and their corresponding genes were identified. Most reductive dehalogenases exhibit similar features such as the presences of a Tat (twin arginine translocation) signal sequence, two Fe‐S clusters, and a corrinoid cofactor. Some of dehalogenase‐encoding genes are found to be flanked by insertion sequences. Thus, dehalogenase genes act as a catabolic transposon, and genetic rearrangements mediated by transposable elements occur well in dehalorespirers. Moreover, the genome sequences of some dehalorespiring bacteria provide many insights into the mechanism of dehalorespiration and the evolution of a dehalogenase gene. © 2008 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 8: 1–12; 2008: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20134
Lactonization‐mediated glycosylations and their application to oligosaccharide synthesis
Authors: Kim Kwan Soo , Jeon Heung Bae
Published: February 2008

The concept of lactonization‐mediated and related glycosylations led us to develop new methods of glycosylation such as the 2′‐carboxybenzyl (CB) glycoside method, the glycosyl pentenoate/phenylselenyl trifluoromethanesulfonate (PhSeOTf) method, and the glycosyl aryl phthalate method. Highly stereoselective β‐mannopyranosylations were achieved by employing the CB glycoside and the glycosyl pentenoate/PhSeOTf methods. The CB glycoside method was also utilized for stereoselective 2‐deoxyglycosylation, β‐arabinofuranosylation, and α‐galactofuranosylation. In addition, these lactonization‐mediated methods of glycosylation were employed for the synthesis of complex oligosaccharides. In particular, the CB glycoside method was successfully applied to the synthesis of repeating oligosaccharide subunits of the O‐polysaccharide of the lipopolysaccharide from Danish Helicobacter pylori strains and Escherichia coli 077, the synthesis of oligoarabinofuranosides in mycobacterial cell walls, and the total synthesis of antineoplastic agelagalastatin. © 2008 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 8: 46–65; 2008: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20138
Characterization of a temperature‐sensitive mutation that impairs the function of yeast tRNA nucleotidyltransferase
Authors: Shan Xunying , Russell Tara A. , Paul Scott M. , Kushner David B. , Joyce Paul B. M.
Published: February 2008

ATP(CTP) : tRNA nucleotidyltransferase catalyses the posttranscriptional addition of cytidine, cytidine and adenosine to the 3′ ends of tRNAs. Previously, a temperature‐sensitive phenotype in Saccharomyces cerevisiae resulting from a mutation in the CCA1 gene coding for this enzyme was identified. Here, we show that a single guanine‐to‐adenine transition in cca1‐1 generates the temperature‐sensitive phenotype. Alignment of the amino acid sequence of S. cerevisiae tRNA nucleotidyltransferase with other tRNA nucleotidyltransferases for which crystal structures have been solved suggests that the resulting Glu‐to‐Lys substitution is in a ß‐turn connecting the structurally and functionally important head and neck domains of the protein. Proteins containing Gln, His or Phe at this position were constructed to further characterize the importance of this residue in enzyme structure and function. As with the Lys variant, the Phe and His variants generate a temperature‐sensitive phenotype in isogenic yeast strains, further supporting the role of this position in maintaining the structure and function of this enzyme. Comparative biophysical and biochemical characterization of both the wild‐type and variant proteins indicates that amino acid substitutions at this position can result in a structural change in the protein that reduces enzyme activity (both at the permissive and non‐permissive temperatures), decreases the melting temperature of the protein and alters its stability at the non‐permissive temperature (37 °C). Copyright © 2008 John Wiley & Sons, Ltd.
Vaccination of eels (Anguilla japonicaandAnguilla anguilla) againstAnguillicola crassuswith irradiated L3
Authors: KNOPF K. , LUCIUS R.
Published: February 2008

The original host of the swimbladder nematodeAnguillicola crassus, the Japanese eel (Anguilla japonica) and the recently colonized European eel (Anguilla anguilla) were immunized with 40 irradiated (500 Gy) 3rd-stage larvae (L3) of this parasite and challenged with an infection of 40 normal L3. The immunization induced a significant reduction of the number of adult worms developing from the challenge infection inA. japonica, but not inA. anguilla. The induced resistance (calculated using the relation of the number of adult worms in immunized eels and in non-immunized control eels) inA. japonicawas 87·3%±30·4%. Following a single infection, the percentage of adult worms found inA. japonicawas lower as compared toA. anguilla, and the few adult worms were much smaller, revealing a lower susceptibility ofA. japonicatoA. crassusin comparison toA. anguilla. Both eel species developed an antibody response againstA. crassus, but the level of antibody responses was not positively correlated with the protection against infection, suggesting that the antibody response is not a key element in resistance of eels againstA. crassus. This study suggests that the original host ofA. crassusis able to mount efficient protective immune responses against its parasite, whereas the newly acquired host seems to lack this ability.
Estimation of the transmission dynamics of Theileria equi and Babesia caballi in horses
Authors: RÜEGG S. R. , HEINZMANN D. , BARBOUR A. D. , TORGERSON P. R.
Published: February 2008

For the evaluation of the epidemiology of Theileria equi and Babesia caballi in a herd of 510 horses in SW Mongolia, several mathematical models of the transmission dynamics were constructed. Because the field data contain information on the presence of the parasite (determined by PCR) and the presence of antibodies (determined by IFAT), the models cater for maternal protection with antibodies, susceptible animals, infected animals and animals which have eliminated the parasite and also allow for age-dependent infection in susceptible animals. Maximum likelihood estimation procedures were used to estimate the model parameters and a Monte Carlo approach was applied to select the best fitting model. Overall, the results are in line with previous experimental work, and add evidence that the epidemiology of T. equi differs from that of Babesia spp. The presented modelling approach provides a useful tool for the investigation of some vector-borne diseases and the applied model selection procedure avoids asymptotical assumptions that may not be adequate for the analysis of epidemiological field data.
An approach of laser induced nuclear fusion
Authors: Imasaki K. , Li D.
Published: February 2008

An approach to an alternative laser fusion in a magnetic field with an intense laser of exa watt level will be discussed. Such a strong field in an exa watt laser will induce enhanced nuclear tunneling through the propagation in plasma. This causes an enhanced nuclear reaction for fusion. We discuss the possibilities to apply this to nuclear fusion energy and to obtain break even in a 100 kJ laser.
Circumpolar occurrence of eugregarinid protozoanCephaloidophora pacificaassociated with Antarctic krill,Euphausia superba
Authors: Takahashi Kunio T. , Kobayashi Masaki , Kawaguchi So , Saigusa Junko , Tanimura Atsushi , Fukuchi Mitsuo , Naganobu Mikio , Toda Tatsuki
Published: February 2008

The geographical distribution of protozoan parasiteCephaloidophora pacificaAvdeev (Order Eugregarininda) associated with Antarctic krill,Euphausia superba, was examined in samples collected from the vicinity of the Antarctic Peninsula, near Syowa Station, and Pacific and Indian sectors of the Southern Ocean.Cephaloidophora pacificawas found at all stations around the Antarctic, with 96.4% of the euphausiids infected (n = 195). The numbers ofC. pacificaper krill ranged from 0 to 8089 krill-1, and the average was 350.0 ± 787.8 (mean ± SD). The frequency distributions ofC. pacificashowed an overdispersed parasite population (i.e. the variance was greater than the mean) at all locations. Statistical analysis showed that whilst the geographical location did not have a significant effect on intensity ofC. pacificathe maturity stage of krill did, with an increasing intensity of infection as krill matures. The infestation ofE. superbaby eugregarinid protozoan is considered to be a circum-Antarctic phenomenon, and it occurs equally throughout the Southern Ocean.
Privileges and novelties: the political discourse of the Flemish cities and rural districts in their negotiations with the dukes of Burgundy (1384–1506)
Authors: DUMOLYN JAN
Published: February 2008

During the negotiations with their Flemish subjects, the Burgundian dukes generally asked for taxes or military aid, while their subjects demanded the confirmation of privileges and the political and economic stability necessary for trade and industry to flourish. In this analysis of the institutionalized bargaining sessions between cities, rural districts and the dukes in Flanders, it will be shown that a specific political discourse developed among the Flemish delegates, that can be considered ‘corporatist’ or ‘communalist’.
The synthesis of town and trade: visualizing provincial urban identity, 1800–1858
Authors: LAYTON-JONES KATY
Published: February 2008

The early nineteenth-century manufacturing town was a diverse and transient environment that inspired a varied canon of printed imagery. Alongside folio engravings and souvenir prints, one of the most prevalent genres of urban imagery was the commercial advertisement. This article demonstrates the value of early pictorial advertisements in accessing contemporary attitudes to urban manufacturing and to provincial urbanization in general. It argues that in a climate of urban rivalry, artists and publishers inherited and invented new visual formulae with which to promote manufactories and commercial premises to tradesmen, consumers and tourists. It concludes that the resulting imagery throws into question the prevalent historical caricature of the early nineteenth-century manufacturing town as a place of deprivation, disorder and decay.
City and empire – local identity and regional imperialism in 1930s Japan
Authors: PHILLIPPS JEREMY
Published: February 2008

The formation of Manchuria in 1932 gave local cities along the Japan Sea coast new hope for development. However, their interpretation of imperialism was in terms of the city rather than the nation. The ways in which these discourses of nation and region played out in ideas of urban development are particularly clear in Kanazawa, the major city on the Japan Sea coast, in the rhetoric surrounding the presentation of empire and region in its exposition that spring.
Konservative und chirurgische Behandlung der oberen Atemwege
Authors: Simmen Daniel B.
Published: February 2008

Die Nase steht im Zentrum der Atemwege und muss deshalb konsequent abgeklärt und therapiert werden, damit ein möglicher Einfluss auf die unteren Atemwege frühzeitig verhindert werden kann. Für eine wirksame Behandlung ist eine genaue, effiziente und verständliche Definition der Erkrankung der oberen Atemwege wichtig. Dem Zusammenspiel der Schleimhautpathologie und der komplexen Mikroanatomie kommt heute im Rahmen der diagnostischen und therapeutischen Richtlinien zur Behandlung von Nasennebenhöhlenerkrankungen eine wesentliche Bedeutung zu. Für die akute Rhinosinusitis kann festgehalten werden, dass eine Antibiotikabehandlung den klinischen Verlauf initial nicht verbessert. Die initale Behandlung kann auf eine symptomatische Therapie beschränkt werden. Eine antibiotische Therapie wird erst nach 7–10-tägiger Symptomatik empfohlen. Der frühzeitige Einsatz von topischen Steroiden ist sinnvoll und zweckmäßig. Die chronische Rhinosinusitis ohne Nasenpolypen wird in erster Linie mit topischen Steroiden behandelt über einen Zeitraum von drei Monaten. Ein Therapieversagen dieser Behandlung soll von einer Langzeit- Makrolidtherapie gefolgt werden über drei weitere Monate. Ein fehlender Erfolg dieser Therapiemaßnahmen zieht die Indikation einer computertomographischen Standortbestimmung nach sich um den Residualbefund der Erkrankung definieren zu können und damit auch die Indikation für ein operatives Vorgehen. Entscheidend ist dabei, dass die Operation den Residualzustand unter medikamentöser Behandlung versorgt und postoperativ die Erkrankung konsequent weiter beobachtet und entsprechend medikamentös weiterbehandelt wird.
Validität des Diagnostischen Interviews bei psychischen Störungen (DIPS für DSM-IV-TR)
Authors: In-Albon Tina , Suppiger Andrea , Schlup Barbara , Wendler Sascha , Margraf Jürgen , Schneider Silvia
Published: February 2008

Zusammenfassung. Theoretischer Hintergrund: Das “Diagnostische Interview bei psychischen Störungen“ (DIPS für DSM-IV-TR; Schneider & Margraf, 2006 ) ist ein strukturiertes Interview, welches erweitert und an die DSM-IV-TR Kriterien angepasst wurde. Fragestellung: Ziel dieser Studie ist die Validierung des DIPS für DSM-IV-TR. Methode: Die Validität der DIPS-Diagnosen wurde mit einer Fragebogenbatterie an einer Stichprobe von 194 Patienten aus unterschiedlichen klinischen Einrichtungen überprüft. Ergebnisse: Die Ergebnisse sprechen für eine gute Validität der Oberklassen Angststörungen, Affektive Störungen, Somatoforme Störungen, Essstörungen, Substanz- und Alkoholmissbrauch/-abhängigkeit sowie einzelner, überprüfbarer Störungskategorien und für den Ausschluss psychischer Störungen. Eine ungenügende Validität ergab sich für die Oberklasse Schlafstörungen und der Generalisierten Angststörung. Schlussfolgerungen: Das DIPS für DSM-IV-TR zeigt außer bei der Generalisierten Angststörung und den Schlafstörungen eine gute Validität bei Patienten ambulanter sowie stationärer psychiatrischer Einrichtungen.
Moderne Gesundheitssorgen und ihre Beziehung zu umweltbezogenen Beschwerden
Authors: Bailer Josef , Bähr Vera , Stübinger Cornelia , Witthöft Michael
Published: February 2008

Zusammenfassung. Theoretischer Hintergrund: Nach Petrie und Wessely (2002) bedeuten neue Technologien (z.B. Mobiltelefone und gentechnologisch veränderte Nahrungsmittel) neue Gesundheitssorgen und -beschwerden. Diese modernen Gesundheitssorgen können mittels Fragebogen standardisiert erfasst werden. Fragestellung: Es wurden die Faktorenstruktur, Reliabilität und Validität einer deutschen Übersetzung der Modern Health Worries (MHW) Scale sowie deren Beziehung zu einem funktionellen umweltbezogenen Syndrom, der Idiopathischen Umweltintoleranz (IUI), untersucht. Methode: 757 Studenten einer deutschen Universität füllten Fragebögen zur Erfassung von MHW, IUI, Krankheitsangst, Depressivität und multiplen körperlichen Beschwerden aus. Ergebnisse: Die vier Subskalen der MHW-Skala - Umweltgifte, Umweltverschmutzung, belastete Nahrungsmittel und elektrische Strahlung - konnten faktorenanalytisch bestätigt werden. Die interne Konsistenz (Cronbach’s α) der Subkalen erreichte Werte zwischen .77 und .89. MHW, negativer Affekt und Somatisierungsneigung trugen als unabhängige Prädiktoren jeweils signifikant zur Vorhersage des IUI-Beschwerdeniveaus bei. Schlussfolgerungen: Die deutsche Version der MHW-Skala kann als Messinstrument zur Verwendung für wissenschaftliche Zwecke empfohlen werden. Die Implikationen der Befunde für ein psychogenes Modell der IUI werden diskutiert.
Epidemiology of Completed Suicides in Singapore for 2001 and 2002
Authors: Loh Marie , Tan Chay Hoon , Sim Kang , Lau Gilbert , Mondry Adrian , Leong Jern-Yi , Tan Ene-Choo
Published: February 2008

Abstract. This study provides an analysis of 640 completed suicide cases in Singapore for the years 2001 and 2002, compared to previous years and in relation to demographic and socioeconomic factors, as well as to the characteristics of a subgroup of suicide victims with prior psychiatric illness. There was little change in the suicide pattern over the 2 years studied compared to previous years. The sex ratio was constant at 1.5. Population-adjusted ratios were 1 for Chinese, 0.5 for Malays, and > 1 for both Indians and other ethnic groups. Falling from heights ranked first in terms of method adopted for both years. A disproportionately higher number of suicides were recorded for the 25-34 and the ≥ 75-year-old age groups. A total of 47 (17.2%) in 2001 and 74 (20.2%) in 2002 of the cases had a history of prior psychiatric illness, with psychotic disorders being the most common diagnostic category. There was also a statistically significant correlation between unemployment and incidence rates. Although the overall rate of elderly suicides had gone down since the 1990s, prevention strategy should focus on the elderly as this rate is still about 3-4 times the national average.
The spiral grid: A new approach to discretize the sphere and its application to mantle convection
Authors: Hüttig Christian , Stemmer Kai
Published: February 2008

This paper presents a new method to generate a three‐dimensional spherical grid using natural neighbor Voronoi cells distributed by spiral functions. A unique property of this grid is the complete removal of symmetries with arbitrary selectable lateral and radial resolution, which are not restricted to discrete radial levels or geometrical constraints as compared to the commonly used grids based on projected triangulated platonic solids such as a cube, a rhomboid, or an icosahedron. The spiral grid can be refined in certain areas of interest and makes it possible to have a very small inner radius to outer radius ratio. Cell volumes can be made almost constant throughout the computational domain. Analysis, statistics, and computation methods are described in detail, as well as a possible domain decomposition suitable for parallel computing. Conductive temperature profiles were numerically calculated in the spherical shell and directly compared with the analytic solution as verification. The grid is applied to numerical simulations of mantle convection using a finite volume scheme. The model is validated by a comparison of steady state cubic and tetrahedral convection patterns with other published models.
Solar wind electron distribution functions inside magnetic clouds
Authors: Nieves‐Chinchilla Teresa , Viñas Adolfo F.
Published: February 2008

This paper presents a study of the kinetic properties of the electron velocity distribution functions within interplanetary magnetic clouds, since they are the dominant thermal component and can contribute as much as 50% of the total electron pressure within the clouds. The study is based on high time resolution data from the Goddard Space Flight Center Wind Solar Wind Experiment vector electron and ion spectrometer. Studies on interplanetary magnetic clouds have shown observational evidence of anticorrelation between the total electron density and temperature, which suggests a polytrope law Pe = αneγ for electrons with the constant γ ≈ 0.5 < 1. This anticorrelation and small γ values are interpreted in the context of the presence of highly non‐Maxwellian electron distributions (i.e., nonthermal tails) within magnetic clouds. We have revisited some of the magnetic cloud events previously studied to quantify the nature of the nonthermal electrons by modeling the electron velocity distribution function using Maxwellian and kappa‐like distribution functions to characterize the kinetic nonthermal effects. The results show that the electron density‐temperature anticorrelation is not a unique feature of magnetic clouds. Within magnetic clouds, κ values are generally small, in the range of 1.6–5.4; however, such small values are also typical of regions outside the clouds. We have shown that the density‐temperature anticorrelation of the electron moments is persistently consistent with similar density‐temperature anticorrelation in the electron halo component of the velocity distribution function and essentially little or no correlation was obtained for the core component. This result clearly shows that the temperature and density of the suprathermal components play a significant role in the temperature‐density anticorrelation because of a relative enhancement of the halo component abundance to the total density.
New paleomagnetic data from Oligocene–upper Miocene sediments in the Rif chain (northern Morocco): Insights on the Neogene tectonic evolution of the Gibraltar arc
Authors: Cifelli Francesca , Mattei Massimo , Porreca Massimiliano
Published: February 2008

In this paper, we present new paleomagnetic data from Tertiary sedimentary sequences of the Rif chain. Paleomagnetic results show that the Rif chain underwent different patterns of vertical axis rotations depending on the tectonic location of the sampled sites. Whereas no paleomagnetic rotations have been measured either in the upper Miocene postnappe basins located along the Mediterranean coast or in the upper Miocene Fes‐Taza foreland basins, upper Miocene thrust top sequences from the external Rif show a significant amount (20° ± 13° in average) of counterclockwise rotations. The spatial distribution of paleomagnetic rotations shows that tectonic rotations, as observed in other arcs of the Mediterranean region, are confined to the orogenic wedge and do not extend to the foreland domain. Paleomagnetic results from this study contribute to better constrain the age of paleomagnetic rotations in the Rif chain, showing that counterclockwise rotations, previously measured only in Mesozoic units, extended into upper Miocene deposits. These results, together with recent published data from the Betics, suggest that the bending of the Gibraltar Arc was not completely achieved by the late Tortonian‐Messinian, enhancing the role of vertical axis rotations in the late Miocene to Recent tectonic evolution of the Gibraltar Arc.
Bio‐optical and structural properties inferred from irradiance measurements within the bottommost layers in an Arctic landfast sea ice cover
Authors: Ehn Jens K. , Mundy C. J. , Barber David G.
Published: February 2008

Irradiance spectra were measured at vertical increments within the bottommost layers of landfast sea ice with the aid of divers in Franklin Bay, Canada, in an effort to obtain input parameters for bio‐optical modeling of sea ice. The study took place between 22 April and 9 May 2004 during the overwintering stage of CASES (Canadian Arctic Shelf Exchange Study). The ice was about 1.8 m thick with a snow cover of variable thickness (∼0.04 to 0.4 m). Ice surface temperatures increased from about −12° to −6.4°C during the sampling period, while ice temperatures within the bottommost portion under study ranged from −3.0° to −1.2°C. Ice algae were visible within the bottommost centimeters of the sea ice. This algae layer had a marked effect on the spectral distribution of transmitted irradiance beneath the ice. Particulate absorption spectra, ap(λ), measured from melted ice samples showed evidence of chloroplastic pigment degradation and could not fully explain the shape of the in situ diffuse attenuation coefficient, Kd(λ), for the algal layer. Interior ice layers, however, did show absorption curves similar to ap(λ) from samples, suggesting the presence of degraded algal pigments within these layers. The discrete ordinates radiative transfer (DISORT) code was iterated in an inverse approach to estimate ap(λ) and the scattering coefficient, btot, from the irradiance profiles. For the bottom 0.1 m of the sea ice, btot was around 400 m−1, while at the 0.1‐ to 0.2‐m layer from the ice bottom it decreased to 165 m−1. Using ap(λ) combined with wavelength independent btot as inputs to DISORT seem to adequately explain the radiative transfer near the bottom of first‐year sea ice provided that adjustments were made to the brine volume fraction.
Two aerodynamic roughness maps derived from Mars Orbiter Laser Altimeter (MOLA) data and their effects on boundary layer properties in a Mars general circulation model (GCM)
Authors: Heavens N. G. , Richardson M. I. , Toigo A. D.
Published: February 2008

Mechanical (forced convective) and free convective turbulent heat and momentum transfer in the lower atmosphere of a terrestrial planet has some dependence on the roughness characteristics of the surface, often quantified in terms of a single roughness parameter which is then used to calculate the coefficients that govern heat and momentum transport between the surface and the boundary layer. We take two different approaches for deriving this aerodynamic roughness parameter for Martian surfaces using data from the Mars Orbiter Laser Altimeter. We then use these two different roughness maps to force the boundary layer in a Mars general circulation model, primarily investigating differences in temperatures and the pressure cycle between the two simulations. While the pressure cycle does not vary significantly, spring and summer high‐latitude temperatures are somewhat sensitive to the input roughness conditions. Daytime temperatures may vary up to 10 K seasonally, though zonally and annually averaged daytime temperatures vary only by ∼1 K. Our results can be explained by the dominance of mechanical over convective turbulent heat transfer processes on Mars. These simulations, however, use a prescribed atmospheric dust distribution and thus only provide a minimum estimate of the uncertainty in boundary layer temperatures because of this plausible range of aerodynamic roughness parameters. Since surface roughness determines the threshold wind velocity for dust lifting we anticipate a much larger effect of the aerodynamic roughness parameter on temperatures when the dust distribution is allowed to vary according to predicted lifting and transport.
On the evolution of salt lakes: Episodic convection beneath an evaporating salt lake
Authors: Nield D. A. , Simmons C. T. , Kuznetsov A. V. , Ward J. D.
Published: February 2008

The transient evolution of salt lake brines and the accompanying underlying groundwater salinity distribution with depth is discussed. A convective‐diffusive equation with a novel surface source term modeling the evaporative process is introduced, and an approximate analytical solution of this equation is obtained using a perturbation approach. A linear stability analysis of the resulting solution is carried out. For typical field‐scale parameters, the model predicts that instability may initially occur within timescales on the order of weeks or decades and that a near‐surface layer of salty fluid whose thickness is on the order of decimeters is responsible for the initial onset of convection. Furthermore, the analysis indicates that when convection starts, the decimeter layer mixes, and this results in the loss of the destabilizing force. In this period, the salty fluid diffuses downward. This results in a return to a hydrologic system, where the salt profile is then well mixed throughout, but now with a background concentration with a higher average salinity. The process can then repeat for an extensive but finite period as the surface layer and subsurface groundwater concentration eventually become hypersaline and where salt precipitation occurs. We have called this phenomenon episodic convection. Variable‐density groundwater flow and solute transport modeling experiments of a field‐based salt lake system confirm the existence of episodic convection and semiquantitatively validate the findings of the analytical approach.
Oxidative Stress through Activation of NAD(P)H Oxidase in Hypertensive Mice with Spontaneous Intracranial Hemorrhage
Authors: Wakisaka Yoshinobu , Miller Jordan D , Chu Yi , Baumbach Gary L , Wilson Saul , Faraci Frank M , Sigmund Curt D , Heistad Donald D
Published: February 2008

We have developed an experimental model of spontaneous intracranial hemorrhage (ICH) in transgenic mice expressing human renin and human angiotensinogen (R+/A+) treated with high-salt diet and Nω-nitro-l-arginine methyl ester (l-NAME). We investigated whether oxidative stress is associated with spontaneous ICH in R+/A+ mice. R+/A+ mice on high-salt diet and l-NAME presented neurologic signs 57±13 (mean±s.e.m.) days after the start of treatment. Intracranial hemorrhage was shown with histologic examination. Levels of superoxide in brain homogenate were significantly increased in R+/A+ mice with ICH (118±10 RLU per sec per mg; RLU, relative light unit) compared with age-matched control mice (19±1) and R+/A+ mice without ICH (53±3). NAD(P)H oxidase activity was significantly higher in R+/A+ mice with ICH (34,933±2,420 RLU per sec per mg) than in control mice (4,984±248) and R+/A+ mice without ICH (15,069±917). These results suggest that increased levels of superoxide are due, at least in part, to increased NAD(P)H oxidase activity. Increased NAD(P)H oxidase activity preceded signs of ICH, and increased further when R+/A+ mice developed ICH. These findings suggest that oxidative stress may contribute to spontaneous ICH in chronic hypertension.
Unsaturated lipid peroxidation-derived aldehydes activate autophagy in vascular smooth-muscle cells
Authors: Hill Bradford G. , Haberzettl Petra , Ahmed Yonis , Srivastava Sanjay , Bhatnagar Aruni
Published: February 2008

Proteins modified by aldehydes generated from oxidized lipids accumulate in cells during oxidative stress and are commonly detected in diseased or aged tissue. The mechanisms by which cells remove aldehyde-adducted proteins, however, remain unclear. Here, we report that products of lipid peroxidation such as 4-HNE (4-hydroxynonenal) and acrolein activate autophagy in rat aortic smooth-muscle cells in culture. Exposure to 4-HNE led to the modification of several proteins, as detected by anti-protein–4-HNE antibodies or protein-bound radioactivity in [3H]4-HNE-treated cells. The 4-HNE-modified proteins were gradually removed from cells. The removal of 4-HNE-modified proteins was not affected by the oxidized protein hydrolase inhibitor, acetyl leucine chloromethyl ketone, or lactacystin, although it was significantly decreased by PSI (proteasome inhibitor I), the lysosome/proteasome inhibitor MG-132 (carbobenzoxy-L-leucyl-L-leucyl-leucinal), insulin or the autophagy inhibitor 3-MA (3-methyladenine). Pre-incubation of cells with rapamycin accelerated the removal of 4-HNE-modified proteins. Treatment with 4-HNE, nonenal and acrolein, but not nonanal or POVPC (1-palmitoyl-2-oxovaleroyl phosphatidyl choline), caused a robust increase in LC3-II (microtubule-associated protein 1 light chain 3-II) formation, which was increased also by rapamycin, but prevented by insulin. Electron micrographs of 4-HNE-treated cells showed extensive vacuolization, pinocytic body formation, crescent-shaped phagophores, and multilamellar vesicles. Treatment with 3-MA and MG-132, but not proteasome-specific inhibitors, induced cell death in 4-HNE-treated cells. Collectively, these results show that lipid peroxidation-derived aldehydes stimulate autophagy, which removes aldehyde-modified proteins, and that inhibition of autophagy precipitates cell death in aldehyde-treated cells. Autophagy may be an important mechanism for the survival of arterial smooth-muscle cells under conditions associated with excessive lipid peroxidation.
Contribution of leptin receptor N-linked glycans to leptin binding
Authors: Kamikubo Yuichi , Dellas Claudia , Loskutoff David J. , Quigley James P. , Ruggeri Zaverio M.
Published: February 2008

The extracellular domain of the human leptin receptor (Ob-R) contains 20 potential N-glycosylation sites whose role in leptin binding remains to be elucidated. We found that a mammalian cell-expressed sOb-R (soluble Ob-R) fragment (residues 22–839 of the extracellular domain) bound leptin with a dissociation constant of 1.8 nM. This binding was inhibited by Con A (concanavalin A) or wheatgerm agglutinin. Treatment of sOb-R with peptide N-glycosidase F reduced leptin binding by ∼80% concurrently with N-linked glycan removal. The human megakaryoblastic cell line, MEG-01, expresses two forms of the Ob-R, of approx. 170 and 130 kDa molecular mass. Endo H (endoglycosidase H) treatment and cell culture with α-glucosidase inhibitors demonstrated that N-linked glycans are of the complex mature type in the 170 kDa form and of the high-mannose type in the 130 kDa form. Both isoforms bound leptin, but not after peptide N-glycosidase F treatment. An insect-cell-expressed sOb-R fragment, consisting of the Ig (immunoglobulin), CRH2 (second cytokine receptor homology) and FNIII (fibronectin type III) domains, bound leptin with affinity similar to that of the entire extracellular domain, but this function was abolished after N-linked glycan removal. The same treatment had no effect on the leptin-binding activity of the isolated CRH2 domain. Our findings show that N-linked glycans within Ig and/or FNIII domains regulate Ob-R function, but are not involved in essential interactions with the ligand.
Matrix metalloproteinase-3 induction in rat brain astrocytes: focus on the role of two AP-1 elements
Authors: Kim Kwang Soo , Kim Hee Young , Joe Eun-hye , Jou Ilo
Published: February 2008

Many brain cells secrete MMPs (matrix metalloproteinases), and increased or misregulated MMP levels are found in neurodegenerative disorders. Here we report that MMP-3 transcription and protein secretion were increased in rat brain astrocytes stimulated with lipopolysaccharide, gangliosides or interferon-γ. Sequential deletion of the MMP-3 promoter revealed that sequences between −0.5 kb and the start codon were crucial for the transcriptional induction of MMP-3. In addition, experiments using pharmacological inhibitors of individual mitogen-activated protein kinases revealed that MMP-3 induction and promoter activity involved Jun N-terminal kinase, a representative upstream signal of AP-1 (activator protein-1). Sequence analyses of the region of the MMP-3 promoter 500 bp from the start codon indicated the presence of three AP-1 binding sequences. Among them, electrophoretic-mobility-shift assays as well as site-directed mutagenesis of individual AP-1 sequences revealed that distal and middle, but not proximal, sequences largely mediated its induction. Together, these results indicate that AP-1 could control MMP-3 induction in brain astrocytes and that its regulation through specific AP-1 elements could be exploited in the treatment of brain pathologies in which increased expression of MMP-3 plays crucial roles.
Deprivation of protein or amino acid induces C/EBPβ synthesis and binding to amino acid response elements, but its action is not an absolute requirement for enhanced transcription
Authors: Thiaville Michelle M. , Dudenhausen Elizabeth E. , Zhong Can , Pan Yuan-Xiang , Kilberg Michael S.
Published: February 2008

A nutrient stress signalling pathway is triggered in response to protein or amino acid deprivation, namely the AAR (amino acid response), and previous studies have shown that C/EBPβ (CCAAT/enhancer-binding protein β) expression is up-regulated following activation of the AAR. DNA-binding studies, both in vitro and in vivo, have revealed increased C/EBPβ association with AARE (AAR element) sequences in AAR target genes, but its role is still unresolved. The present results show that in HepG2 human hepatoma cells, the total amount of C/EBPβ protein, both the activating [LAP* and LAP (liver-enriched activating protein)] and inhibitory [LIP (liver-enriched inhibitory)] isoforms, was increased in histidine-deprived cells. Immunoblotting of subcellular fractions and immunostaining revealed that most of the C/EBPβ was located in the nucleus. Consistent with these observations, amino acid limitation caused an increase in C/EBPβ DNA-binding activity in nuclear extracts and chromatin immunoprecipitation revealed an increase in C/EBPβ binding to the AARE region in vivo, but at a time when transcription from the target gene was declining. A constant fraction of the basal and increased C/EBPβ protein was phosphorylated on Thr235 and the phospho-C/EBPβ did bind to an AARE. Induction of AARE-enhanced transcription was slightly greater in C/EBPβ-deficient MEFs (mouse embryonic fibroblasts) or C/EBPβ siRNA (small interfering RNA)-treated HepG2 cells compared with the corresponding control cells. Transient expression of LAP*, LAP or LIP in C/EBPβ-deficient fibroblasts caused suppression of increased transcription from an AARE-driven reporter gene. Collectively, the results demonstrate that C/EBPβ is not required for transcriptional activation by the AAR pathway but, when present, acts in concert with ATF3 (activating transcription factor 3) to suppress transcription during the latter stages of the response.
Enhanced cell-surface stability of rescued ΔF508 cystic fibrosis transmembrane conductance regulator (CFTR) by pharmacological chaperones
Authors: Varga Karoly , Goldstein Rebecca F. , Jurkuvenaite Asta , Chen Lan , Matalon Sadis , Sorscher Eric J. , Bebok Zsuzsa , Collawn James F.
Published: February 2008

Misfolded proteins destined for the cell surface are recognized and degraded by the ERAD [ER (endoplasmic reticulum) associated degradation] pathway. TS (temperature-sensitive) mutants at the permissive temperature escape ERAD and reach the cell surface. In this present paper, we examined a TS mutant of the CFTR [CF (cystic fibrosis) transmembrane conductance regulator], CFTR ΔF508, and analysed its cell-surface trafficking after rescue [rΔF508 (rescued ΔF508) CFTR]. We show that rΔF508 CFTR endocytosis is 6-fold more rapid (∼30% per 2.5 min) than WT (wild-type, ∼5% per 2.5 min) CFTR at 37 °C in polarized airway epithelial cells (CFBE41o−). We also investigated rΔF508 CFTR endocytosis under two further conditions: in culture at the permissive temperature (27 °C) and following treatment with pharmacological chaperones. At low temperature, rΔF508 CFTR endocytosis slowed to WT rates (20% per 10 min), indicating that the cell-surface trafficking defect of rΔF508 CFTR is TS. Furthermore, rΔF508 CFTR is stabilized at the lower temperature; its half-life increases from <2 h at 37 °C to >8 h at 27 °C. Pharmacological chaperone treatment at 37 °C corrected the rΔF508 CFTR internalization defect, slowing endocytosis from ∼30% per 2.5 min to ∼5% per 2.5 min, and doubled ΔF508 surface half-life from 2 to 4 h. These effects are ΔF508 CFTR-specific, as pharmacological chaperones did not affect WT CFTR or transferrin receptor internalization rates. The results indicate that small molecular correctors may reproduce the effect of incubation at the permissive temperature, not only by rescuing ΔF508 CFTR from ERAD, but also by enhancing its cell-surface stability.
Calcium-dependent Pyk2 activation: a role for calmodulin?
Authors: Schaller Michael D.
Published: February 2008

Pyk2 (proline-rich tyrosine kinase 2) and FAK (focal adhesion kinase) are highly related tyrosine kinases. One distinguishing feature is the differential regulation of the two enzymes in response to elevation of cytoplasmic calcium. In the latest issue of the Biochemical Journal, Sasaki and co-workers have provided insight into the calcium-dependent regulation of Pyk2. The findings suggest that calmodulin may bind the FERM (4.1/ezrin/radixin/moesin) domain to promote Pyk2 activation in response to calcium signals triggered by vasopressin. While the molecular details of the protein–protein interaction and mechanism of activation remain to be firmly established, this study is the first to provide mechanistic insight into the regulation of Pyk2 by calcium.
Terahertz scanning imaging with a subwavelength plastic fiber
Authors: Lu Ja-Yu , Chiu Chui-Min , Kuo Chung-Chiu , Lai Chih-Hsien , Chang Hung-Chung , Hwang Yuh-Jing , Pan Ci-Ling , Sun Chi-Kuang
Published: February 2008

The feasibility to perform fiber-scanning terahertz imaging utilizing a terahertz subwavelength plastic fiber is investigated. Our study shows that, with a low (<1%) fractional power inside the fiber core, the bending loss of the terahertz subwavelength fiber is acceptable to enable large area scanning without seriously sacrificing the signal-to-noise ratio of the acquired image. With a transmission geometry, this feasibility is demonstrated by direct two-dimensional scanning of the terahertz subwavelength fiber output end to image different biological samples and concealed substances.
Application of compact electron cyclotron resonance ion source
Authors: Muramatsu M. , Kitagawa A. , Iwata Y. , Ogawa H. , Hojo S. , Kubo T. , Kato Y. , Biri S. , Fekete E. , Yoshida Y. , Drentje A. G.
Published: February 2008

The compact electron cyclotron resonance (ECR) ion source with a permanent magnet configuration (Kei2 source) has been developed at National Institute of Radiological Sciences for a new carbon therapy facility. The Kei2 source was designed for production of C4+ ions; its performance such as beam intensity and stability has already reached the medical requirements. Therefore, the prototype development of the source for medical use is essentially finished. Recently, we have started a few studies on other applications of the source. One is the production of fullerenes in the ECR plasma and modified fullerenes with various atoms for new materials. A second application is the production of multiply charged ions (not only carbon) for ion implantation. In this paper, some basic experiments for these applications are reported.
Novel mechanism of photoinduced magnetism in organic-based magnetic semiconductor V(TCNE)x, x∼2
Authors: Yoo Jung-Woo , Edelstein R. Shima , Raju N. P. , Lincoln D. M. , Epstein A. J.
Published: February 2008

The organic-based magnet V(TCNE)x, x∼2 (Tc∼400K), is a room temperature magnetic semiconductor with spin polarized valence and conduction bands. It was reported that this material exhibits persistent photoinduced change in both magnetization and conductivity. The simultaneous change in IR spectra by illumination shows photoinduced activation to the metastable state with a small structural change. Here, we employed photoinduced ferrimagnetic resonance (FMR) study to investigate photoinduced magnetization in V(TCNE)x film. The FMR spectra display substantial changes in their linewidth and line shift by the illumination indicating substantial increase in random magnetic anisotropy. The results demonstrate optical control of magnetism by changing magnetic anisotropy of the system.