bluuebunny/crossref_metadata_2025 huggingface dataset:
Re-suspension of bed sediment in a small stream – results from two flushing experiments
Authors: Eder A. , Exner-Kittridge M. , Strauss P. , Blöschl G.
Published: March 2014

Abstract. Streams draining small watersheds often exhibit multiple peaking sedigraphs associated with single peaking hydrographs. The process reasons of the multiple sediment peaks are not fully understood but they may be related to the activation of different sediment sources such as the stream bed itself, where deposited sediments from previous events may be available for resuspension. To understand resuspension of stream bed sediments at the reach scale we artificially flooded the small stream of the HOAL Petzenkirchen catchment in Austria by pumping sediment-free water into the stream. Two short floods were produced and flow, sediment and bromide concentrations were measured at three sites with high temporal resolution. Hydrologically, the two flood events were almost identical. The peak flows decreased from 57 to 7.9 L s−1 and the flow volumes decreased from 17 to 11.3 m2 along the 590 m reach of the stream. However, a considerably smaller sediment load was resuspended and transported during the second flood due to depletion of stream bed sediments. The exception was the middle section of the stream, where more sediment was transported during the second flood event which can be explained by differences between flow velocity and wave celerity and the resulting displacement of sediments within the stream. The results indicate that the first peak of the sedigraphs of natural events in this stream is indeed caused by the resuspension of stream bed sediments, accounting for up to six percent of the total sediment load depending on total flow volume.
Simulated tritium concentrations in river waters of the western Lake Taupo catchment, New Zealand with MODPATH particle tracking
Authors: Gusyev M. A. , Abrams D. , Toews M. W. , Morgenstern U. , Stewart M. K.
Published: March 2014

Abstract. We simulated in a previous study tritium concentrations in the river waters of the western Lake Taupo catchment (WLTC) using MODFLOW/MT3DMS model (Gusyev et al., 2013). The model was calibrated to match simulated tritium to measured tritium in river waters at baseflows of the Waihaha, Whanganui, Whareroa, Kuratau and Omori river catchments of the WLTC. Following from this work we now utilized the same MODFLOW model for the WLTC to calculate the pathways of groundwater particles (and their corresponding tritium concentrations) using steady-state particle tracking with MODPATH. In order to simulate baseflow tritium concentrations with MODPATH, transit time distributions (TTDs) such as cumulative frequency distribution (CFD) and probability density function (PDF) are generated with particle tracking for the river networks of the five WLTC catchment outflows. Then, PDFs are used in the convolution integral with tritium concentration time series obtained in the precipitation. The resulting MODPATH tritium concentrations yield a very good match to measured tritium concentrations and are similar to the MT3DMS simulated tritium concentrations, with the greatest variation occurring around the bomb peak. MODPATH and MT3DMS also yield similar Mean Transit Times (MTT) of groundwater contribution to river baseflows, but the actual shape of the TTDs is strikingly different. While both distributions provide valuable information, the methodologies used to derive the TTDs are fundamentally different and hence must be interpreted differently. With the current models setting, only the methodology used with MODPATH provides the true TTD for use with the convolution integral.
Evaluating a mesoscale atmosphere model and a satellite-based algorithm in estimating extreme rainfall events in northwestern Turkey
Authors: Yucel I. , Onen A.
Published: March 2014

Abstract. Quantitative precipitation estimates are obtained with more uncertainty under the influence of changing climate variability and complex topography from numerical weather prediction (NWP) models. On the other hand, hydrologic model simulations depend heavily on the availability of reliable precipitation estimates. Difficulties in estimating precipitation impose an important limitation on the possibility and reliability of hydrologic forecasting and early warning systems. This study examines the performance of the Weather Research and Forecasting (WRF) model and the Multi Precipitation Estimates (MPE) algorithm in producing the temporal and spatial characteristics of the number of extreme precipitation events observed in the western Black Sea region of Turkey. Precipitation derived from WRF model with and without the three-dimensional variational (3DVAR) data assimilation scheme and MPE algorithm at high spatial resolution (5 km) are compared with gauge precipitation. WRF-derived precipitation showed capabilities in capturing the timing of precipitation extremes and to some extent the spatial distribution and magnitude of the heavy rainfall events, whereas MPE showed relatively weak skills in these aspects. WRF skills in estimating such precipitation characteristics are enhanced with the application of the 3DVAR scheme. Direct impact of data assimilation on WRF precipitation reached up to 12% and at some points there is a quantitative match for heavy rainfall events, which are critical for hydrological forecasts.
Implementation and evaluation of prognostic representations of the optical diameter of snow in the SURFEX/ISBA-Crocus detailed snowpack model
Authors: Carmagnola C. M. , Morin S. , Lafaysse M. , Domine F. , Lesaffre B. , Lejeune Y. , Picard G. , Arnaud L.
Published: March 2014

Abstract. In the SURFEX/ISBA-Crocus multi-layer snowpack model, the snow microstructure has up to now been characterised by the grain size and by semi-empirical shape variables which cannot be measured easily in the field or linked to other relevant snow properties. In this work we introduce a new formulation of snow metamorphism directly based on equations describing the rate of change of the optical diameter (dopt). This variable is considered here to be equal to the equivalent sphere optical diameter, which is inversely proportional to the specific surface area (SSA). dopt thus represents quantitatively some of the geometric characteristics of a porous medium. Different prognostic rate equations of dopt, including a re-formulation of the original Crocus scheme and the parameterisations from Taillandier et al. (2007) and Flanner and Zender (2006), were evaluated by comparing their predictions to field measurements carried out at Summit Camp (Greenland) in May and June 2011 and at Col de Porte (French Alps) during the 2009/10 and 2011/12 winter seasons. We focused especially on results in terms of SSA. In addition, we tested the impact of the different formulations on the simulated density profile, the total snow height, the snow water equivalent (SWE) and the surface albedo. Results indicate that all formulations perform well, with median values of the RMSD between measured and simulated SSA lower than 10 m2 kg−1. Incorporating the optical diameter as a fully fledged prognostic variable is an important step forward in the quantitative description of the snow microstructure within snowpack models, because it opens the way to data assimilation of various electromagnetic observations.
Quantification of Hemodialysis Dose: What Kt/V to Choose?
Authors: Aatif Taoufiq , Hassani Kawtar , Alayoud Ahmed , Zajjari Yassir , Maoujoud Omar , Benyahia Mohamed , Oualim Zouhair
Published: March 2014

Background

Quantification of hemodialysis became more accurate and easier after the advent of ionic dialysance and the use of methods for estimating urea distribution volume (V). The aim of this study was to compare different methods of hemodialysis dose assessment: Kt/VDau (Daugirdas 2nd generation), Kt/VOCM (Kt by OCM (Online Clearance Monitor) and V by Watson), and Kt/VBCM (Kt by OCM and V by bio-impedance); and to assess the dialysis adequacy, defined by a Kt/V≥1.4.

Design

Prospective, observational study.

Methods

35 hemodialysis sessions were evaluated in 35 chronic hemodialysis patients. During each session, we measured simultaneously, Kt/VOCM, Kt/VBCM and calculated Kt/VDau by performing blood samples before and after each session.

Results

35 patients, gender (M/F: 19/16), mean age of 50.49 years, were evaluated. We noted a difference between the three methods of evaluating Kt/V index: Kt/VDau, Kt/VOCM and Kt/VBCM (1.82 ± 0.29; 1.45 ± 0.23; 1.8 ± 0.33, p<0.001). Comparison of Kt/VOCM with Kt/VDau and Kt/VBCM leads to a significant systematic underestimate of Kt/V by 22% and 20.5% respectively. Better agreement between Kt/VDau and Kt/VBCM was observed. The adequate hemodialysis was achieved, according to three methods: Kt/VDau, Kt/VOCM and Kt/VBCM respectively in 100%, 57,1% and 88.6% of the cases.

Conclusions

The Kt/V index is different depending on the method used for its evaluation. The three methods can be used for quantification of hemodialysis with a better agreement between Kt/VDau and Kt/VBCM. In this study, Kt/VOCM results underestimate hemodialysis efficiency. This difference has to be considered when applying quantification of hemodialysis to clinical practice.
Response of Angiopoietin-like Proteins 3 and 4 to Hemodialysis
Authors: Mahmood Dana , Makoveichuk Elena , Nilsson Solveig , Olivecrona Gunilla , Stegmayr Bernd
Published: March 2014

Background/Aim

Patients on chronic hemodialysis (cHD) have decreased activity of lipoprotein lipase (LPL). Angiopoietin-like proteins (ANGPTL) 3 and 4 have been shown to inactivate LPL. The aim of this study was to investigate the levels of the ANGPTLs in plasma of cHD-patients and to evaluate if cHD may alter these levels.

Material and methods

Baseline data were collected from cHD patients (n = 23), and controls (n = 23) and samples were analyzed from 17 patients during low-flux or high-flux HD, and from ultrafiltrate (n = 5). The levels of ANGPTL3 and 4, LPL and triglycerides were studied in a cross-over design on cHD with local citrate compared to tinzaparin as anticoagulant.

Results

The level of ANGPTL3 was higher than ANGPTL4 in patients and controls (p<0.01); the ANGPTL3 was 2.0 and ANGPTL4 was 3.3-fold higher in cHD versus controls. The levels of ANGPTL4 increased during cHD. After 180 min of HD the values had decreased again. When the dialysis was performed with high-flux filter, the mean level of ANGPTL4 at 180 min was below the value observed before cHD (p = 0.003). There was immunoreaction for ANGPTL4 in UFs when using high-flux, but not with low-flux, filter. ANGPTL3 was not detectable in UF. On cHD with citrate, no LPL activity was released into the blood

Conclusions

ANGPTL3 and ANGPTL4 were increased in HD patients. Anticoagulation with tinzaparin during cHD causes release of ANGPTL4 from tissues into blood. cHD using high-flux filters, to some extent, removed ANGPTL4. With citrate the levels of ANGPTL4 decreased.
On the Afrotropical genus Holmelgonia (Araneae, Linyphiidae), with the description of three new species from the Albertine Rift
Authors: Nzigidahera Benoît , Jocqué Rudy
Published: March 2014

Three new species of Holmelgonia were found in the mountain forest of Kibira National Park in Burundi: H. afromontana sp. nov. (♂♀), H. bosnasutus sp. nov. (♂♀) and H. disconveniens sp. nov. (♂). A key to the males in the genus, now containing 17 species, is provided.
Les revues et la littérature in flagrante : de Valery Larbaud à la littérature québécoise contemporaine
Authors: Lacroix Michel
Published: March 2014

« J’avais souvent pensé que pour les futurs historiens de la littérature moderne, les revues seraient d’un grand profit et principalement les revues de jeunes écrivains, parce qu’on pouvait y suivre, de mois en mois, le cours de la “littérature qui se faisait” », écrivait Valery Larbaud au début du xxe siècle. Malgré le développement remarquable des travaux sur les revues, cette histoire n’a pas encore été écrite. Cependant l’idée m’est chère et c’est sous son aiguillon que je souhaite réfléchir à l’étude historique de la littérature contemporaine, en quittant les revues littéraires françaises des années 1900 à 1920 pour les revues littéraires québécoises des dix dernières années. Le saut d’une époque et d’un domaine littéraire à l’autre, loin d’être balayé sous le tapis, servira de point de départ à mon interrogation. Peut-on toujours souligner, comme Larbaud le faisait, « l’importance capitale des revues » dans la littérature qui se fait maintenant ? Les revues servent-elles toujours de rampe de lancement pour les oeuvres nouvelles, de catalyseur esthétique pour les regroupements d’écrivains, de lieu de confrontation entre les écritures d’une même époque, voire de vecteur de « contemporanéité » ? Ces questions sur l’historicité des revues suscitent, du même souffle, une interrogation sur les méthodes de l’histoire littéraire.
La famille martiniquaise à l’épreuve des migrations de retour : nouvelles pratiques de mobilité transatlantique et dynamiques transnationales
Authors: Lanthier Aude
Published: March 2014

On assiste de nos jours à de nouvelles pratiques de mobilité entre l’Île-de-France et son département ultramarin, la Martinique, dont les migrations de retour font partie intégrante. Si circuler entre la métropole et l’archipel est aujourd’hui de l’ordre du quotidien, on constate pourtant une certaine irritation à l’égard des migrants de retour. En effet, une étude ethnographique a permis de révéler que ceux-ci témoignent de plusieurs obstacles à l’heure de réintégrer leur terre d’origine. Le présent article s’attardera plus spécifiquement aux bouleversements des rapports familiaux engendrés par les phénomènes de retour au pays natal et aux nouvelles dynamiques d’hypermobilité circulatoire entre la France et son ex-colonie, dynamiques qui confèrent à ces familles réparties de part et d’autre de l’Atlantique des allures de familles dites « transnationales ».
La procédure en matière d’intégrité de la personne, entre spécificité et transposition. Un enjeu de droits fondamentaux
Authors: Bernheim Emmanuelle
Published: March 2014

À partir d’une recherche sur le terrain sur la garde en établissement et l’autorisation de soins, l’auteure se questionne sur le rôle spécifique de la procédure en matière d’intégrité de la personne. Alors qu’une lecture littérale des textes permet de conclure que ces dispositions ont un rôle de protection des droits, la pratique en la matière dénote une transposition des paradigmes conceptuels et interprétatifs propres à la procédure civile « classique », les réduisant à une fonction d’organisation judiciaire. Or, ici, l’application de la procédure est garante d’une décision cohérente et prévisible au regard du droit substantiel, et permet de corriger, du moins partiellement, le déséquilibre évident des parties au litige. C’est en ce sens que la procédure en matière d’intégrité de la personne peut contribuer à la réalisation du rôle de l’institution judiciaire au regard des inégalités sociales et juridiques.
Réponses suggérées aux questions soulevées par le renvoi à la Cour suprême du Canada concernant la réforme du Sénat
Authors: Pelletier Benoît
Published: March 2014

Le 1er février 2013, le gouverneur général en conseil a soumis, sur recommandation du ministre de la Justice, un certain nombre de questions relatives à la réforme du Sénat pour avis de la Cour suprême du Canada. Dans ce texte, l’auteur nous fait part des réponses que, selon lui, la Cour devrait apporter aux questions qui lui sont posées dans ce nouveau renvoi. L’auteur en vient à la conclusion qu’aucun changement significatif à la durée du mandat des sénateurs, comme les modifications proposées par le gouvernement fédéral dans son renvoi, ne peut être accompli unilatéralement par le Parlement en vertu de l’article 44 de la Loi constitutionnelle de 1982. Du reste, il en vient à la même conclusion en ce qui touche à la tenue des « consultations populaires » concernant le choix des sénateurs, et ce, peu importe que ces dernières se déroulent sur la base d’élections fédérales, provinciales ou territoriales. Selon l’auteur, ces « consultations » ne peuvent pas davantage être tenues en vertu des pouvoirs législatifs réguliers du Parlement, ni être encadrées par une simple loi fédérale. L’auteur estime que le Parlement peut abroger unilatéralement le paragraphe 23(4) de la Loi constitutionnelle de 1867 en ce qui touche à la valeur des propriétés mobilières et immobilières des sénateurs, mais il invite la Cour suprême à ne pas se prononcer sur l’abrogation du paragraphe 23(3) de cette loi, faute de précisions sur les intentions fédérales. Puis, l’auteur estime que c’est bel et bien la procédure dite du 7/50, et non la règle de l’unanimité, qui permet l’abolition pure et simple du Sénat. Enfin, l’auteur examine la possible application de certains principes constitutionnels sous-jacents à la réforme du Sénat.
Cree Peoplehood, International Trade, and Diplomacy
Authors: Jobin Shalene
Published: March 2014

Self-determination for Indigenous peoples in settler-colonial countries like Canada is an ongoing process where Indigenous peoples simultaneously focus externally to create expanded jurisdictional space while also re-establishing their own governing processes. Canadian economic progress has come at a cost to Indigenous peoples, undermining their collective rights to economic security and self-determination. In this article, I explore Cree peoplehood as a way to conceive Cree nationhood as distinct from conceptions of the nation-State. I rely significantly on archival sources to explore how the Cree were, and were also seen as, a self-determining people. After exploring the internal aspects of Cree peoplehood, I then examine the external relations of the Cree: focusing on inter-nation trade, trade networks, transportation, and a trade language as nations engage in trade and diplomacy, as one method to exercise their authority and jurisdiction. The final section investigates the diplomatic relations of the Plains Cree. This article is adding to the peoplehood literature by not only applying this concept to domestic relations but also examining foreign relations. It also adds to the writing on Cree self-determination by exploring how historic relationships and practices can inform current self-determination aspirations. This type of research can substantiate and provide historical analyses of Indigenous nationhood to further understand the context behind current economic and political self-determination movements.
Could you have said no? A mixed‐methods investigation of consent to HIV tests in four African countries
Authors: Obermeyer Carla Makhlouf , Verhulst Cairn , Asmar Khalil ,   for the MATCH study group
Published: March 2014

Introduction

Although most studies report high frequencies of consent to HIV tests, critics argue that clients are subject to pressure, that acceptors later indicate they could not have refused, and that provider‐initiated HIV testing raises serious ethical issues. We examine the meaning of consent and why clients think they could not have refused.

Methods

Clients in Burkina Faso, Kenya, Malawi and Uganda were asked about consenting to HIV tests, whether they thought they could have refused and why. Textual responses were analyzed using qualitative and statistical methods.

Results

Among 926 respondents, 77% reported they could not have said no, but in fact, 60% actively consented to test, 24% had no objection and only 7% tested without consent. There were few significant associations between categories of consent and their covariates.

Conclusions

Retrospectively asking clients if they could have refused to test for HIV overestimates coercion. Triangulating qualitative and quantitative data suggests a considerable degree of agency.
Synthesis of metal nanoparticles by dual plasma electrolysis using atmospheric dc glow discharge in contact with liquid
Authors: Shirai Naoki , Uchida Satoshi , Tochikubo Fumiyoshi
Published: March 2014

For the synthesis of metal nanoparticles in aqueous solution, we propose dual plasma electrolysis, which consists of a Hoffman electrolysis apparatus with two atmospheric glow discharge plasmas as electrodes instead of conventional metal electrodes immersed in a liquid. The plasma anode irradiates positive ions to the solution surface while the plasma cathode irradiates electrons to the solution surface. The dual plasma electrolysis system enables us to simultaneously investigate the influence of electron and positive ion irradiation to a solution surface on metal nanoparticle generation at the same current. In this work, we used aqueous solutions of AgNO3, HAuCl4, and their mixture. In dual plasma electrolysis with AgNO3, Ag nanoparticles were only synthesized on the plasma cathode side. This means that Ag nanoparticles are generated via the reduction of Ag+ by electrons. With HAuCl4 solution, Au nanoparticles were synthesized on both the plasma anode and plasma cathode sides. Ion irradiation with the plasma anode is more effective than electron irradiation for Au nanoparticle synthesis. This finding suggests that positive ions from the plasma trigger the dissociative reaction of AuCl4
− at the plasma–liquid interface. When a AgNO3–HAuCl4 mixture was used, the synthesized nanoparticles have a structure consisting of a Au core covered with a Ag shell.
Effect of ambient air on n-type carbon nanotube thin-film transistors chemically doped with poly(ethylene imine)
Authors: Yasunishi Tomohiro , Kishimoto Shigeru , Ohno Yutaka
Published: March 2014

Chemical doping with poly(ethylene imine) (PEI) is often used to produce n-type carbon nanotube thin-film transistors (CNT TFTs) with stability in air. However, the effect of air on the device characteristics has not yet been fully investigated. In this study, we performed a detailed investigation on how the oxygen and water present in air affect stability issues, including hysteresis, current collapse, and ambipolar properties of PEI-doped n-type CNT TFTs fabricated on a transparent plastic film. We found that current collapse and hysteresis are predominantly caused by the combination of water and oxygen, suggesting that a water/oxygen redox reaction is responsible for the instability of PEI-doped devices. Water vapor has a rather more severe impact in the case of PEI-doped devices than in the case of undoped CNT TFTs because of the hygroscopicity of PEI. Surface passivation with Al2O3, deposited by a low-temperature atomic layer deposition technique, notably improved the stability of the device properties in ambient air.
Transparent conducting zinc nitride films
Authors: Yamada Naoomi , Watarai Kouki , Yamaguchi Takahiro , Sato Atsushi , Ninomiya Yoshihiko
Published: March 2014

Highly conducting Zn3N2 thin films were reactively sputtered on unheated glass. Well-crystallized polycrystalline films were obtained even though the films were deposited at a low temperature. Nitrogen-deficient Zn3N2 films exhibited n-type conductivity and resistivities of the order of 10−3 Ω cm. All the obtained Zn3N2 films had sufficiently high electron mobilities in the range of 30 to 66 cm2 V−1 s−1. Such high mobilities probably originate from the small electron effective mass of 0.27m
0 (where m
0 denotes free electron mass), which was confirmed by infrared reflectance measurements. Furthermore, we found that intentional oxygen doping reduced the resistivities of Zn3N2 thin films to 8.9 × 10−4 Ω cm. Optical measurements revealed that the direct optical band gap of the Zn3N2 films was in the range of 2.9–3.1 eV. These results suggest that impurity-doped Zn3N2 is a candidate for a new nitride-based transparent conductor.
Pockmark formation and evolution in deep water Nigeria: Rapid hydrate growth versus slow hydrate dissolution
Authors: Sultan N. , Bohrmann G. , Ruffine L. , Pape T. , Riboulot V. , Colliat J.‐L. , De Prunelé A. , Dennielou B. , Garziglia S. , Himmler T. , Marsset T. , Peters C.A. , Rabiu A. , Wei J.
Published: March 2014

In previous works, it has been suggested that dissolution of gas hydrate can be responsible for pockmark formation and evolution in deep water Nigeria. It was shown that those pockmarks which are at different stages of maturation are characterized by a common internal architecture associated to gas hydrate dynamics. New results obtained by drilling into gas hydrate‐bearing sediments with the MeBo seafloor drill rig in concert with geotechnical in situ measurements and pore water analyses indicate that pockmark formation and evolution in the study area are mainly controlled by rapid hydrate growth opposed to slow hydrate dissolution. On one hand, positive temperature anomalies, free gas trapped in shallow microfractures near the seafloor and coexistence of free gas and gas hydrate indicate rapid hydrate growth. On the other hand, slow hydrate dissolution is evident by low methane concentrations and almost constant sulfate values 2 m above the Gas Hydrate Occurrence Zone.
Structure of the ionized lunar sodium and potassium exosphere: Dawn‐dusk asymmetry
Authors: Yokota Shoichiro , Tanaka Takaaki , Saito Yoshifumi , Asamura Kazushi , Nishino Masaki N. , Fujimoto Masaki , Tsunakawa Hideo , Shibuya Hidetoshi , Matsushima Masaki , Shimizu Hisayoshi , Takahashi Futoshi
Published: March 2014

We present latitude and longitude distributions of Na+ and K+ fluxes from the Moon derived from Kaguya low‐energy ion data. Although the latitude distribution agrees with previous ground‐based telescope observations, dawn‐dusk asymmetry has been determined in the longitude distribution. Our model of the lunar surface abundance and yield of Na and K demonstrates that the abundance decreases to approximately 50% at dusk compared with that at dawn due to the emission of the exospheric particles assuming the ion fluxes observed by Kaguya are proportional to the yield. It is also implied that the surface abundance of Na and K need to be supplied during the night to explain the observed lunar exosphere with dawn‐dusk asymmetry. We argue that the interplanetary dust as well as grain diffusion and migration/recycling of the exospheric particles may be major suppliers.
Digging Into the World Beneath Our Feet: Bridging Across Scales in the Age of Global Change
Authors: Hinckley Eve‐Lyn S. , Wieder William , Fierer Noah , Paul Eldor
Published: March 2014

Climate change, land use practices, and other consequences of a growing human population affect soil sustainability. Unfortunately, scientists studying belowground processes have traditionally been limited to data and models that capture intermediate spatial and temporal scales, failing to accurately characterize soil phenomena at societally relevant scales, including the larger spatial scales at which many policy decisions are made.
Canada's subarctic lakes could face widespread desiccation
Authors: Schultz Colin
Published: March 2014

In Canada's subarctic—the boreal ecosystem that spans most of mainland Canada—the temperature is climbing, and the snowpack is thinning. Previous research has shown that snow is disappearing even faster than sea ice.
Migrating quake swarm may indicate magma conduit clog
Authors: Schultz Colin
Published: March 2014

On 13 January 2006, Augustine Volcano, a towering volcano offshore from the Alaska Peninsula, erupted explosively. In the days leading up to the eruption, a series of explosions and earthquake swarms had warned of the impending activity. On 12 January, 36 hours before the first magmatic explosions, a swarm of 54 earthquakes was detected across the 13‐station seismic network on Augustine Island. Analyzing the seismic waves produced by the earthquakes, Buurman and West found that the earthquakes were being triggered from point sources within the magma conduit itself.
Associations Between Pressure–Pain Threshold, Symptoms, and Radiographic Knee and Hip Osteoarthritis
Authors: Goode Adam P. , Shi Xiaoyan A. , Gracely Richard H. , Renner Jordan B. , Jordan Joanne M.
Published: March 2014

Objective

To determine the association between generalized evoked pressure pain sensitivity with distal pressure–pain threshold (PPT) and the presence, severity, or number of involved knee/hip joints with radiographic osteoarthritis (rOA) or related symptoms.

Methods

Data for these cross‐sectional analyses come from the second followup (2008–11) of the Johnston County Osteoarthritis Project (n = 1,602). PPT measurements were averaged over 2 trials from both the left and right trapezius. Outcomes of radiographic knee and hip OA were both defined by a Kellgren/Lawrence score of 2–4 and site‐specific symptoms were ascertained at clinical interview. Associations were determined with multiple logistic regression models and two‐way interactions were tested at P < 0.05.

Results

The sample was 67.2% women and 31.0% African American. Participants' mean ± SD age was 67.9 ± 9.0 years, mean ± SD body mass index was 31.5 ± 7.1 kg/m2, mean ± SD Center for Epidemiologic Studies Depression Scale score was 6.5 ± 7.4, and mean ± SD total PPT was 3.6 ± 0.7 kg. Significant associations were found between PPT and self‐reported knee/hip symptoms. No significant associations were found between PPT and presence, severity, or number of joints with knee and hip rOA without accompanying symptoms. No significant interactions were found with demographic or clinical characteristics.

Conclusion

PPT was significantly associated with self‐reported single and multijoint symptoms. In contrast, after adjustment, PPT measured at the trapezius was not associated with asymptomatic knee or hip rOA. As such, PPT may prove to be a useful indicator of rOA pain processing and of why individuals respond favorably and others do not to treatments targeting rOA.
Incidence and Risk Factors for Thoracic Spine Pain in the Working Population: The French Pays de la Loire Study
Authors: Roquelaure Yves , Bodin Julie , Ha Catherine , Le Marec Fabien , Fouquet Natacha , Ramond‐Roquin Aline , Goldberg Marcel , Descatha Alexis , Petit Audrey , Imbernon Ellen
Published: March 2014

Objective

To examine the incidence and risk factors for incident thoracic spine pain (TSP) in workers representative of a French region's working population.

Methods

In this prospective study, 3,710 workers were assessed in 2002–2005, and 2,332 (62.9%) of them were reassessed in 2007–2010. TSP was assessed by a self‐administered Nordic questionnaire at baseline and at followup. At baseline, all participants completed a self‐administered questionnaire on personal factors and work exposure. A total of 1,886 subjects (1,124 men and 762 women) without TSP at baseline were eligible for analysis. Associations between incident TSP and risk factors at baseline were analyzed by multivariate logistic regression.

Results

The incidence rate of TSP was 5.2 (95% confidence interval [95% CI] 3.9–6.6) per 100 men and 10.0 (95% CI 7.8–12.1) per 100 women. TSP was often associated with low back pain and neck pain. TSP in men was associated with age (odds ratios [ORs] ranging from 2.6 [95% CI 0.95–7.1] at 30–39 years to 6.0 [95% CI 2.1–17.3] at ≥50 years), being tall (OR 2.2 [95% CI 1.2–3.9]), frequent/sustained trunk bending (OR 3.0 [95% CI 1.5–6.1]), lack of recovery period or change in the task (OR 2.0 [95% CI 1.2–3.6]), and driving vehicles (OR 2.8 [95% CI 1.4–5.5]). Being overweight or obese was associated with lower risk (OR 0.5 [95% CI 0.3–0.96]). TSP in women was associated with high perceived physical workload (OR 1.9 [95% CI 1.1–3.3]), after adjustment for confounding variables.

Conclusion

The risk model of TSP combined personal and work‐related organizational and physical factors. Trunk bending appeared to be a strong independent predictor of TSP in this working population.
Dielectric Relaxation Processes, Electronic Structure, and Band Gap Engineering of MFU‐4‐type Metal‐Organic Frameworks: Towards a Rational Design of Semiconducting Microporous Materials
Authors: Sippel Pit , Denysenko Dmytro , Loidl Alois , Lunkenheimer Peter , Sastre German , Volkmer Dirk
Published: March 2014

The electronic structures and band gaps of MFU‐4‐type metal‐organic frameworks can be systematically engineered leading to a family of isostructural microporous solids. Electrical properties of the microcrystalline samples are investigated by temperature‐dependent broad‐band dielectric and optical spectroscopy, which are corroborated by full band structure calculations performed for framework and cluster model compounds at multiple levels of density functional theory. The combined results glean a detailed picture of relative shifts and dispersion of molecular orbitals when going from zero‐dimensional clusters to three‐dimensional periodic solids, thus allowing to develop guidelines for tailoring the electronic properties of this class of semiconducting microporous solids via a versatile building block approach. Thus, engineering of the band gap in MFU‐4 type compounds can be achieved by adjusting the degree of conjugation of the organic ligand or by choosing an appropriate metal whose partially occupied d‐orbitals generate bands below the LUMO energy of the ligand which, for example, is accomplished by octahedral Co(II) ions in Co‐MFU‐4.
Scaling Behavior of Resistive Switching in Epitaxial Bismuth Ferrite Heterostructures
Authors: Rana Abhimanyu , Lu Haidong , Bogle Kashinath , Zhang Qi , Vasudevan Rama , Thakare Vishal , Gruverman Alexei , Ogale Satishchandra , Valanoor Nagarajan
Published: March 2014

Resistive switching (RS) of (001) epitaxial multiferroic BiFeO3/La0.67Sr0.33MnO3/SrTiO3 heterostructures is investigated for varying lengths scales in both the thickness and lateral directions. Macroscale current–voltage analyses in conjunction with local conduction atomic force microscopy (CAFM) reveal that whilst both the local and global resistive states are strongly driven by polarization direction, the type of conduction mechanism is different for each distinct thickness regime. Electrode‐area dependent studies confirm the RS is dominated by an interface mechanism and not by filamentary formation. Furthermore, CAFM maps allow deconvolution of the roles played by domains and domain walls during the RS process. It is shown that the net polarization direction, and not domain walls, controls the conduction process. An interface mechanism based on barrier height and width alteration due to polarization reversal is proposed, and the role of electronic reconstruction at the interface is further investigated.
Materials and Structures for Stretchable Energy Storage and Conversion Devices
Authors: Xie Keyu , Wei Bingqing
Published: March 2014

Stretchable energy storage and conversion devices (ESCDs) are attracting intensive attention due to their promising and potential applications in realistic consumer products, ranging from portable electronics, bio‐integrated devices, space satellites, and electric vehicles to buildings with arbitrarily shaped surfaces. Material synthesis and structural design are core in the development of highly stretchable supercapacitors, batteries, and solar cells for practical applications. This review provides a brief summary of research development on the stretchable ESCDs in the past decade, from structural design strategies to novel materials synthesis. The focuses are on the fundamental insights of mechanical characteristics of materials and structures on the performance of the stretchable ESCDs, as well as challenges for their practical applications. Finally, some of the important directions in the areas of material synthesis and structural design facing the stretchable ESCDs are discussed.
Magnetically Retrievable Nano Crystalline Nickel Ferrite‐ Catalyzed Aerobic, Ligand‐Free CN, CO and CC Cross‐ Coupling Reactions for the Synthesis of a Diversified Library of Heterocyclic Molecules
Authors: Paul Sanjay , Pradhan Koyel , Ghosh Sirshendu , De S. K. , Das Asish R.
Published: March 2014

A new nickel ferrite nano‐crystal‐catalyzed, ligand‐free strategy for the construction of CN, CO, and CC bonds is presented, in which easily available nitrogen and oxygen nucleophiles, aryl/heteroaryl halides and arylboronic acids are used for the cross‐coupling reactions. The reactions can be performed at low catalyst loadings with excellent functional group tolerance and chemoselectivity. A variety of functional groups are compatible with the reaction conditions, including nitro, methoxy, as well as acid‐ and base‐sensitive heteroaromatic groups. This unprecedented chemistry nicely complements classical methods for the N‐arylation of amines/heteroamines, the O‐arylation of phenols/hydroxycoumarins and biaryl/heteroaryl synthesis. The low cost, easy to handle nature and the simplicity of this catalytic system render the method competitive with comparable copper‐ and palladium‐based protocols which require the presence of sophisticated ligands. Nickel ferrite magnetic nanoparticles were prepared by a simple hydrothermal method and characterized by using XRD, TEM image, energy dispersive X‐ray analysis, XPS and FT‐IR. The easy recovery of the catalyst and high yield of the products make the protocol attractive, sustainable and economic. The catalyst was reused for five cycles with almost unaltered catalytic activity.

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Synthesis of Furanose Spirooxindoles via 1,8‐Diazabicyclo[5.4.0]undec‐7‐ene (DBU)‐Catalyzed Aldol Reactions of a Pyruvic Aldehyde Derivative
Authors: Zhang Dongxin , Johnson Sherida , Cui Hai‐Lei , Tanaka Fujie
Published: March 2014

Spirooxindoles are important compounds as they are often found in bioactive molecules. Thus, the development of new spirooxindoles and of synthetic routes to spirooxindoles is a great interest to discover new biofunctional molecules and therapeutic leads. We developed a concise method for the synthesis of spirooxindoles bearing a furanose unit. 1,8‐Diazabicyclo[5.4.0]undec‐7‐ene (DBU) was used for an aldol reaction of a pyruvic aldehyde derivative with isatin; reduction of the ketone group was followed by treatment with acid to generate the spirofuranose unit. A set of furanose spirooxindoles were obtained in good to high yields.
Development of a Peptide‐Based Primary Aminocatalyst with a Helical Structure
Authors: Akagawa Kengo , Suzuki Rieko , Kudo Kazuaki
Published: March 2014

A resin‐supported peptide with an N‐terminal primary amino group was developed as a primary aminocatalyst and used in the asymmetric Michael addition of nitromethane to α,β‐unsaturated ketones. These peptides with helical motifs, that is, polyleucine and a repeated Leu‐Leu‐Aib (Aib=2‐aminoisobutyric acid) sequence, efficiently catalyzed the reaction. The introduction of two tryptophan residues at the N‐terminus of the helical peptides improved the enantioselectivity of the reaction, and using the catalysts in aqueous media enhanced the reaction rate. The versatility of the optimum catalyst with the (Trp)2‐(Leu‐Leu‐Aib)3 sequence was demonstrated by applying it to other organocatalytic reactions such as the Michael addition of malonates to α,β‐unsaturated ketones and a three‐component, sequential reaction with methacrolein.
Ruthenium(V) Oxides from Low‐Temperature Hydrothermal Synthesis
Authors: Hiley Craig I. , Lees Martin R. , Fisher Janet M. , Thompsett David , Agrestini Stefano , Smith Ronald I. , Walton Richard I.
Published: March 2014

Low‐temperature (200 °C) hydrothermal synthesis of the ruthenium oxides Ca1.5Ru2O7, SrRu2O6, and Ba2Ru3O9(OH) is reported. Ca1.5Ru2O7 is a defective pyrochlore containing RuV/VI; SrRu2O6 is a layered RuV oxide with a PbSb2O6 structure, whilst Ba2Ru3O9(OH) has a previously unreported structure type with orthorhombic symmetry solved from synchrotron X‐ray and neutron powder diffraction. SrRu2O6 exhibits unusually high‐temperature magnetic order, with antiferromagnetism persisting to at least 500 K, and refinement using room temperature neutron powder diffraction data provides the magnetic structure. All three ruthenates are metastable and readily collapse to mixtures of other oxides upon heating in air at temperatures around 300–500 °C, suggesting they would be difficult, if not impossible, to isolate under conventional high‐temperature solid‐state synthesis conditions.
Stereoselektive Metall‐freie Synthese von β‐Aminothioestern mit tertiären und quartären Stereozentren
Authors: Bahlinger Annette , Fritz Sven P. , Wennemers Helma
Published: March 2014

β‐Aminothioester sind wichtige Bausteine für die Synthese bioaktiver Moleküle. Hier wurden organokatalytische Mannich‐Reaktionen entwickelt, die direkten und stereoselektiven Zugang zu β2‐ und β2,3,3‐Aminothioestern ausgehend von simplen Bausteinen bieten. Mechanistische Untersuchungen zeigen, dass der stereochemische Verlauf der Reaktion durch die Wahl des Substrates kontrolliert wird. Die linearen Produkte, die benachbarte tertiäre und quartäre Stereozentren enthalten, konnten durch stereoselektive Decarboxylierung und Entschützung weiter zu β2,3‐Bausteinen funktionalisiert werden. Außerdem demonstrieren wir den großen präparativen Wert der β‐Aminothioester durch die Anwendung in einer Kupplungsreagens‐freien Peptidsynthese.
On‐Chip Spyhole Mass Spectrometry for Droplet‐Based Microfluidics
Authors: Gasilova Natalia , Yu Qiuliyang , Qiao Liang , Girault Hubert H.
Published: March 2014

For efficient coupling of droplet‐based microfluidics with mass spectrometry (MS), a spyhole drilled on the top of a microchip is used to sample the passing droplets by electrostatic‐spray ionization (ESTASI) MS. The technique involves placing an electrode below the chip under the spyhole and applying high‐voltage pulses. Electrospray occurs directly from the spyhole, and the droplet content is analyzed by MS without a dilution or oil removal step. To demonstrate the versatility of this technique, we have successfully monitored a droplet‐based tryptic digestion, as well as a biphasic reaction between β‐lactoglobulin in water and α‐tocopheryl acetate in 1,2‐dichloroethane, where the protein extracts the antioxidant from the oil phase and becomes reduced.
Ein flüchtiges Lacton aus Hymenoscyphus pseudoalbidus, dem Pathogen der Europäischen Esche, inhibiert die Keimung seines Wirtes
Authors: Citron Christian A. , Junker Corina , Schulz Barbara , Dickschat Jeroen S.
Published: March 2014

Der weitgehend unbekannte Sekundärmetabolismus des phytopathogenen Pilzes Hymenoscyphus pseudoalbidus wurde mittels der CLSA‐Methode untersucht. Eine Serie flüchtiger Lactone wurde per GC/MS identifiziert. Die Lactone wurden synthetisiert und in einem Bioaktivitätstest eingesetzt, in dem eine der Verbindungen als starker Keimungsinhibitor gegenüber Eschensamen auffiel. Diese Verbindung verursachte überdies Nekrosen im pflanzlichen Gewebe.
Axially Chiral Imidodiphosphoric Acid Catalyst for Asymmetric Sulfoxidation Reaction: Insights on Asymmetric Induction
Authors: Jindal Garima , Sunoj Raghavan B.
Published: March 2014

Insights into chiral induction for an asymmetric sulfoxidation reaction involving a single oxygen atom transfer are gained through analyzing the stereocontrolling transition states. The fitting of the substrate into the chiral cavity of a new class of imidodiphosphoric Brønsted acids, as well as weak CH⋅⋅⋅π and CH⋅⋅⋅O noncovalent interactions, are identified as responsible for the observed chiral induction.
cis‐Specific Hydrofluorination of Alkenylarenes under Palladium Catalysis through an Ionic Pathway
Authors: Emer Enrico , Pfeifer Lukas , Brown John M. , Gouverneur Véronique
Published: March 2014

This paper describes the hydrofluorination of alkenes through sequential H− and F+ addition under palladium catalysis. The reaction is cis specific, thus providing access to benzylic fluorides. The mechanism of this reaction involves an ionic pathway and is distinct from known hydrofluorinations involving radical intermediates. The first catalytic enantioselective hydrofluorination is also disclosed.
Lamellar‐Twisting‐Induced Circular Dichroism of Chromophore Moieties in Banded Spherulites with Evolution of Homochirality
Authors: Li Ming‐Chia , Wang Hsiao‐Fang , Chiang Chen‐Hung , Lee Yu‐Der , Ho Rong‐Ming
Published: March 2014

Banded spherulites are formed by crystallization of a chiral polymer that is end‐capped with chromophore. Induced circular dichroism (ICD) of the chromophore can be found in the crystallized chiral polymers, giving exclusive optical response of the ICD. The ICD signals are presumed to be driven by the lamellar twisting in the crystalline spherulites, and the exclusive optical activity is attributed to the chirality transfer from molecular level to macroscopic level. To verify the suggested mechanism, the sense of the lamellar twisting in the crystalline spherulite is determined using PLM for the comparison with the ICD signals of the chromophore in the electron circular dichroism spectrum. The conformational chirality of the chiral polymer is determined by the vibrational circular dichroism spectrum. On the basis of the chiroptical results, evolution of homochirality from helical polymer chains (conformational chirality) to lamellar twisting in the banded spherulite (hierachical chirality) is suggested.
Stereoselective Metal‐Free Synthesis of β‐Amino Thioesters with Tertiary and Quaternary Stereogenic Centers
Authors: Bahlinger Annette , Fritz Sven P. , Wennemers Helma
Published: March 2014

β‐Amino thioesters are important natural building blocks for the synthesis of numerous bioactive molecules. An organocatalyzed Mannich reaction was developed which provides direct and highly stereoselective access to acyclic β2‐ and β2,3,3‐amino thioesters with adjacent tertiary and quaternary stereocenters. Mechanistic studies showed that the stereochemical course of the reaction can be controlled by the choice of the substrates. The β‐amino thioesters were further functionalized by, for example, stereoselective decarboxylation to access β2,3‐frameworks. In addition, the value of the β‐amino thioesters was shown in coupling‐reagent‐free peptide synthesis.
Total Chemical Synthesis and Biological Activities of Glycosylated and Non‐Glycosylated Forms of the Chemokines CCL1 and Ser‐CCL1
Authors: Okamoto Ryo , Mandal Kalyaneswar , Ling Morris , Luster Andrew D. , Kajihara Yasuhiro , Kent Stephen B. H.
Published: March 2014

CCL1 is a naturally glycosylated chemokine protein that is secreted by activated T‐cells and acts as a chemoattractant for monocytes.1 Originally, CCL1 was identified as a 73 amino acid protein having one N‐glycosylation site,1 and a variant 74 residue non‐glycosylated form, Ser‐CCL1, has also been described.2 There are no systematic studies of the effect of glycosylation on the biological activities of either CCL1 or Ser‐CCL1. Here we report the total chemical syntheses of both N‐glycosylated and non‐glycosylated forms of (Ser‐)CCL1, by convergent native chemical ligation. We used an N‐glycan isolated from hen egg yolk together with the Nbz linker for Fmoc chemistry solid phase synthesis of the glycopeptide‐αthioester building block.3 Chemotaxis assays of these glycoproteins and the corresponding non‐glycosylated proteins were carried out. The results were correlated with the chemical structures of the (glyco)protein molecules. To the best of our knowledge, these are the first investigations of the effect of glycosylation on the chemotactic activity of the chemokine (Ser‐)CCL1 using homogeneous N‐glycosylated protein molecules of defined covalent structure.
The Bioinorganic Chemistry of Apoptosis: Potential Inhibitory Zinc Binding Sites in Caspase‐3
Authors: Daniel A. Gerard , Peterson Erica J. , Farrell Nicholas P.
Published: March 2014

Zn2+ inhibits the action of several of the caspases and thus may act as a regulator of apoptosis. Reversal of this inhibition is one possible approach for the development of apoptosis‐based therapies. Few studies describe the molecular details of the Zn2+–caspase interaction, the understanding of which is essential for the success of any therapeutic strategies. Enzyme kinetics and biophysical studies have shown that the inhibition is of mixed type with prominent (ca. 60 % of inhibition) uncompetitive characteristics and an IC50 of 0.8 μM under the conditions used. Fluorescence‐based techniques confirmed that, during inhibition in the sub‐micromolar range, substrate binding remains unaffected. A new zinc binding site composed of the catalytic histidine and a nearby methionine residue, rather than the catalytic histidine and cysteine dyad, is proposed based on the experimental observations. DFT models were used to demonstrate that the proposed site could be the preferred inhibitory zinc binding site.