bluuebunny/crossref_metadata_2025 huggingface dataset:
Isotopic composition of nitrate in wet and dry atmospheric deposition on Crete in the eastern Mediterranean Sea
Authors: Mara Paraskevi , Mihalopoulos Nikolaos , Gogou Alexandra , Daehnke Kirstin , Schlarbaum Tim , Emeis Kay‐Christian , Krom Michael
Published: September 2009

The eastern Mediterranean Sea (EMS) is a nutrient‐poor ocean with unusually high nitrate‐phosphate ratios (up to 28:1) and relatively depleted 15N/14N ratios (expressed as δ15N) in deepwater nitrate (δ15NO3− of 2.5‰) and sediments (<3.5‰) that have been attributed to extensive N2 fixation. To quantify the role of atmospheric NO3− deposition in the N cycle in the EMS, we analyzed NO3− and its δ15N in samples of dry and wet deposition on biweekly and per event basis from April 2006 to September 2007 on the island of Crete. Both dry and wet deposition samples have consistently negative δ15N compared to air N2, implying a strongly depleted atmospheric source calculated to be (weighted annual estimate) −3.1‰. The low δ15N of wet deposition is in agreement with data from other environments, but the consistently depleted nature of dry deposition is unusual and supports the view of an origin from association of atmospheric NO3− mainly with dust and sea salt. This situation is due to high levels of sulphate compared to ammonium, sea salt, and lithogenic material. Mass balance and isotope‐mixing calculations show that the present‐day inputs of nitrate from external sources into the surface water layer of the eastern Mediterranean Sea have a weighted mean δ15N‐NO3− of 0.5‰ to 1.5‰ and that particle flux to and mineralization in the deepwater pool over the last 40–50 years can account for the unusually low δ15N ratios found in deepwater NO3− without the need of any significant N2 fixation.
On the deformation cycle of a strongly coupled plate interface: The triple earthquakes of 16 March 1963, 15 November 2006, and 13 January 2007 along the Kurile subduction zone
Authors: Raeesi M. , Atakan K.
Published: September 2009

The great plate interface Kurile earthquake of 15 November 2006 (Mw = 8.3) was immediately followed by normal aftershocks in the outer rise of the central Kurile subduction zone. Two months later at a distance <50 km from this event the 13 January 2007 (Mw = 8.1) earthquake with a pure normal mechanism occurred in the outer rise of the central Kurile. The 15 November 2006 earthquake ruptured an area of 280 × 150 km2 with maximum slip of almost 7 m, while the 13 January 2007 earthquake ruptured an area of 240 × 40 km2 with a maximum slip of almost 14 m. These two significant events were preceded by a major reverse earthquake on 16 March 1963 (Mw = 7.7) that took place close to the location of the 13 January 2007 earthquake. These very different earthquakes demonstrate the different stages of the deformation cycle along strongly coupled plates at the central Kurile arc and present a rare case of stress regime reversal over a short time span. In order to understand the details of these three earthquakes, we inverted for the source rupture processes of the earthquakes and delineated the location and dimension of asperities. The role of gravity and topography anomalies and their correlation to the asperity distribution as well as the long‐term seismicity is studied in detail. Using trench‐parallel Bouguer anomaly, we have identified the differences in the asperities and the location of larger normal outer rise aftershocks as well as the location of 13 January 2007 earthquake. We also show that the long‐term seismicity of the central Kurile arc is confined to the intraslab and not the plate interface. The static stress transfer for these earthquakes showed that the stress on optimally oriented thrust faults is increased in the northeastern part of the rupture area of the 15 November 2006 earthquake. Absence of major and great earthquakes to the northeastern immediate vicinity of the rupture area of the 15 November 2006 earthquake supports the hypothesis that this area is mature for the next strong earthquake along the Kurile arc.
Leafless roughness of complex tree morphology using terrestrial lidar
Authors: Antonarakis A. S. , Richards K. S. , Brasington J. , Bithell M.
Published: September 2009

Strategies for extracting roughness parameters from riparian forests need to address the issue that the trees are more than just stems and that in large rivers flow can rise into the canopy. Remote sensing information with 3‐D capabilities such as lidar can be used to extract information on trees. However, first and last pulse airborne lidar data are insufficient to characterize the complex vertical structure of vegetation because by definition, there are few data at intermediate levels. Terrestrial laser scanning (TLS) is used in this study to define complex structures at a millimetric scanning resolution for the purpose of extracting canopy parameters relevant for the parameterization of the flow resistance equations. We will mainly be concerned with the projected area of leafless trees, estimating the total tree dimensions using several different methods. These include manipulating mass point cloud data obtained from TLS to create stage‐dependent projected areas through complex meshing techniques and voxelization. Stage‐dependent projected areas were defined for natural and planted poplar forests in the riparian zone of the Garonne and Allier rivers in southern and central France, respectively. Roughness values for planted poplar forests dominant in many western European river floodplains range from Manning's n = 0.037–0.094 and n = 0.140–0.330 for below‐canopy flow (2 m) and extreme in‐canopy flow (8 m), respectively. Roughness values for natural poplar forests ranged from n = 0.066–0.210 and n = 0.202–0.720 for below‐canopy flow (2 m) and extreme in‐canopy flow (8 m), respectively.
Improving Stream Studies With a Small‐Footprint Green Lidar
Authors: McKean Jim , Isaak Dan , Wright Wayne
Published: September 2009

Technology is changing how scientists and natural resource managers describe and study streams and rivers. A new generation of airborne aquatic‐terrestrial lidars is being developed that can penetrate water and map the submerged topography inside a stream as well as the adjacent subaerial terrain and vegetation in one integrated mission. A leading example of these new cross‐environment instruments is the Experimental Advanced Airborne Research Lidar (EAARL), a NASA‐built sensor now operated by the U.S. Geological Survey (USGS) [Wright and Brock, 2002].

Standard airborne terrestrial lidars, which currently produce the highest‐resolution maps of extensive land areas, use reflected near‐infrared laser pulses to make millions of point measurements of ground and vegetation elevations. However, near‐infrared energy is absorbed by water, which limits the use of these systems to mapping features outside of water bodies. EAARL uses a narrow‐beam green, rather than near‐infrared, laser with a footprint of only 15 centimeters from the nominal flying height (for system technical specifications, see Table S1 in the electronic supplement to this Eos issue (http://www.agu.org/eos_elec/).
Young Paleoclimate Scientists Meet to Broaden Knowledge and Build Ties: PAGES 1st Young Scientists Meeting: Retrospective Views on Our Planet's Future; Corvallis, Oregon, 6–7 July 2009
Authors: Reyes Alberto , Gagen Mary
Published: September 2009

Paleoenvironmental science provides important context for assessing ongoing and projected changes in Earth's climate and has informed research on central issues such as greenhouse gas variability, abrupt climate change, and ice sheet dynamics. Studies of the past have provided insight into natural climate variability at interannual to glacial/interglacial timescales and have fostered appreciation for a systems approach to global environmental change.

As a contribution to the future of paleoscience, the Past Global Changes (PAGES) project, an international effort sponsored by the National Oceanic and Atmospheric Administration (NOAA) and the Swiss and U.S. National Science Foundations to coordinate and promote past global climate change research, convened its 1st Young Scientists Meeting (YSM) in July 2009, as an adjunct to the subsequent 3rd Open Science Meeting. Early career researchers were given the opportunity to broaden their knowledge base, build international and cross‐disciplinary networks, tackle emerging issues of concern to the paleoscience community, and learn about international science infrastructures.
South American rainfall impacts associated with inter‐El Niño variations
Authors: Hill K. J. , Taschetto A. S. , England M. H.
Published: September 2009

The impacts of inter‐El Niño events on South American circulation during austral summer are investigated using observations and an atmospheric general circulation model (AGCM). The AGCM was forced with sea surface temperature (SST) anomalies in the tropical Pacific for the two El Niño events of 1997/1998 (EN97) and 2002/2003 (EN02). The strong eastern Pacific SST anomaly of EN97 resulted in a typical displacement of the Walker circulation, causing a decrease in precipitation across the north of South America. A strengthened low‐level jet (LLJ) east of the Andes during EN97 enhanced the moisture transport from low latitudes to the subtropics, leading to intensified precipitation over southeastern South America. The simulated circulation in EN02 reveals a weakened LLJ and anomalous convergence of moisture over eastern South America, which can be attributed to a displacement of the Pacific‐South American (PSA) mode in response to the different location of the heat sources along the tropical Pacific Ocean.
Analyzing input and structural uncertainty of nonlinear dynamic models with stochastic, time‐dependent parameters
Authors: Reichert Peter , Mieleitner Johanna
Published: September 2009

A recently developed technique for identifying continuous‐time, time‐dependent, stochastic model parameters is embedded in a general framework for identifying causes of bias and reducing bias in dynamic models. In contrast to the usual approach of considering bias in model output with an autoregressive error model or a stochastic process, we make the attempt to correct for bias within the model or even in model input. This increases the potential of learning about the causes of bias and of subsequently correcting deficits of the deterministic model structure. The time‐dependent parameters as formulated in our approach can also consistently be used for adding stochasticity to the model without losing precise fulfilment of conservation laws used for deriving the model equations. An additional advantage of the suggested procedure is that it makes it possible to derive more realistic uncertainty bounds of internal model variables than is the case when bias is only considered for measured model output. This is important for mechanistic models in which internal variables have a direct physical meaning. The concept is illustrated by an application to a simple eight‐parameter conceptual hydrological model. This application demonstrates the feasibility of the proposed approach and gives an impression of its potential for application to a large class of nonlinear, dynamic models.
Evaluation of the PBR/TSPO Radioligand [18F]DPA-714 in a Rat Model of Focal Cerebral Ischemia
Authors: Martín Abraham , Boisgard Raphaël , Thézé Benoit , Van Camp Nadja , Kuhnast Bertrand , Damont Annelaure , Kassiou Michael , Dollé Frédéric , Tavitian Bertrand
Published: September 2009

Focal cerebral ischemia leads to an inflammatory reaction involving an overexpression of the peripheral benzodiazepine receptor (PBR)/18-kDa translocator protein (TSPO) in the cerebral monocytic lineage (microglia and monocyte) and in astrocytes. Imaging of PBR/TSPO by positron emission tomography (PET) using radiolabeled ligands can document inflammatory processes induced by cerebral ischemia. We performed in vivo PET imaging with [18F]DPA-714 to determine the time course of PBR/TSPO expression over several days after induction of cerebral ischemia in rats. In vivo PET imaging showed significant increase in DPA ( N,N-diethyl-2-(2-(4-(2-fluoroethoxy)phenyl)-5,7-dimethylpyrazolo[1,5-a]pyrimidin-3-yl)acetamide) uptake on the injured side compared with that in the contralateral area on days 7, 11, 15, and 21 after ischemia; the maximal binding value was reached 11 days after ischemia. In vitro autoradiography confirmed these in vivo results. In vivo and in vitro [18F]DPA-714 binding was displaced from the lesion by PK11195 and DPA-714. Immunohistochemistry showed increased PBR/TSPO expression, peaking at day 11 in cells expressing microglia/macrophage antigens in the ischemic area. At later times, a centripetal migration of astrocytes toward the lesion was observed, promoting the formation of an astrocytic scar. These results show that [18F]DPA-714 provides accurate quantitative information of the time course of PBR/TSPO expression in experimental stroke.
Trafficking of Glucose, Lactate, and Amyloid-β from the Inferior Colliculus through Perivascular Routes
Authors: Ball Kelly K , Cruz Nancy F , Mrak Robert E , Dienel Gerald A
Published: September 2009

Metabolic brain imaging is widely used to evaluate brain function and disease, and quantitative assays require local retention of compounds used to register changes in cellular activity. As labeled metabolites of [1- and 6-14C]glucose are rapidly released in large quantities during brain activation, this study evaluated release of metabolites and proteins through perivascular fluid flow, a pathway that carries solutes from brain to peripheral lymphatic drainage sites. Assays with [3,4-14C]glucose ruled out local oxidation of glucose-derived lactate as a major contributor of label loss. Brief infusion of [1-14C]glucose and D-[14C]lactate into the inferior colliculus of conscious rats during acoustic stimulation labeled the meninges, consistent with perivascular clearance of [14C]metabolites from interstitial fluid. Microinfusion of Evans blue albumin and amyloid-β1−40 (Aβ) caused perivascular labeling in the inferior colliculus, labeled the surrounding meninges, and Aβ-labeled-specific blood vessels in the caudate and olfactory bulb and was deposited in cervical lymph nodes. Efflux of extracellular glucose, lactate, and Aβ into perivascular fluid pathways is a normal route for clearance of material from the inferior colliculus that contributes to underestimates of brain energetics. Convergence of ‘watershed’ drainage to common pathways may facilitate perivascular amyloid plaque formation and pathway obstruction in Alzheimer's disease.
Intact Lipid Rafts Regulate HIV-1 Tat Protein-Induced Activation of the Rho Signaling and Upregulation of P-Glycoprotein in Brain Endothelial Cells
Authors: Zhong Yu , Hennig Bernhard , Toborek Michal
Published: September 2009

The Rho signaling has an essential function in human immunodeficiency virus (HIV)-1-mediated disruption of the integrity of the blood–brain barrier (BBB). However, it is unknown how membrane domains, such as lipid rafts, can influence HIV-1-mediated activation of the Rho pathway and how these processes can affect the expression of the efflux transporters at the BBB level. This study is focused on the function of HIV-1 protein Tat in activation of the Rho signaling and upregulation of P-glycoprotein (P-gp) in human brain endothelial cells. Treatment with Tat markedly elevated GTP-RhoA levels and the potential downstream effectors, such as myosin phosphatase target subunit 1 and myosin light chain. In addition, Tat upregulated expression and promoter activity of P-gp as well as its efflux function. Inhibition of the Rho signaling cascade effectively blocked P-gp overexpression at the level of promoter activity. Disruption of lipid rafts by depletion of membrane cholesterol by methyl-beta-cyclodextrin, but not caveolin-1 silencing, also abolished Tat-mediated RhoA activation and P-gp upregulation. The present data indicate the critical function of intact lipid rafts and the Rho signaling in HIV-1-mediated upregulation of P-gp and potential development of drug resistance in brain endothelial cells.
Optical hydrogen detection with periodic subwavelength palladium hole arrays
Authors: Maeda Etsuo , Mikuriya Sho , Endo Koichi , Yamada Ichiro , Suda Atsushi , Delaunay Jean-Jacques
Published: September 2009

The extraordinary transmission of infrared light through subwavelength rectangular hole arrays of palladium is used to detect hydrogen. The main resonance peak of rectangular hole arrays is found to shift upon exposure to hydrogen. Experimental evidence of the change in the Pd phase, producing a shift toward longer wavelengths of the main resonance peak, is presented and supported by simulations that agree with experimental observation. The all-optical and selective detection scheme of hydrogen produces large peak shifts that enable the detection of hydrogen concentration near the lower flammability threshold in air.
Shear effects in lateral piezoresponse force microscopy at 180° ferroelectric domain walls
Authors: Guyonnet J. , Béa H. , Guy F. , Gariglio S. , Fusil S. , Bouzehouane K. , Triscone J.-M. , Paruch P.
Published: September 2009

In studies using piezoresponse force microscopy, we observe a nonzero lateral piezoresponse at 180° domain walls in out-of-plane polarized, c-axis-oriented tetragonal ferroelectric Pb(Zr0.2Ti0.8)O3 epitaxial thin films. We attribute these observations to a shear strain effect linked to the sign change of the d33 piezoelectric coefficient through the domain wall, in agreement with theoretical predictions. We show that in monoclinically distorted tetragonal BiFeO3 films, this effect is superimposed on the lateral piezoresponse due to actual in-plane polarization and has to be taken into account in order to correctly interpret the ferroelectric domain configuration.
Band alignment and electron traps in Y2O3 layers on (100)Si
Authors: Wang W. C. , Badylevich M. , Afanas’ev V. V. , Stesmans A. , Adelmann C. , Van Elshocht S. , Kittl J. A. , Lukosius M. , Walczyk Ch. , Wenger Ch.
Published: September 2009

Y 2 O 3 films deposited by atomic vapor deposition on (100)Si with a 2 or 5 nm thick pregrown thermal SiO2 are investigated as possible charge trapping layers. Analysis of these structures using spectroscopic ellipsometry, photoconductivity, and internal photoemission reveals that Y2O3 has a 5.6 eV wide optical bandgap and a 2.0 eV conduction band offset with silicon. Photo(dis)charging experiments show that the optical energy depth of most of the traps exceeds 1.5 eV with respect to the Y2O3 conduction band, explaining the observed charge retention time of ∼108 s at room temperature, even in the absence of a blocking insulator.
Enhancement in current efficiency in organic light-emitting diodes with incorporation of subphthalocyanine
Authors: Chen Yu-Hung , Chang Jung-Hung , Lee Guan-Ru , Wu I-Wen , Fang Jheng-Hao , Wu Chih-I , Pi Tun-Wen
Published: September 2009

A highly efficient hole injection material, boron subphthalocyanine chloride (SubPc), was incorporated in organic light-emitting diodes. Device performance is greatly enhanced by inserting an ultrathin layer of SubPc between anodes and N,N′-di(naphthalene-1-yl)-N,N′-diphenyl-benzidene (NPB). Electronic structures and chemical reaction at the interface between NPB and SubPc are also investigated by photoemission spectroscopy with synchrotron radiation sources. Extra states are observed at the forbidden gap of SubPc with deposition of NPB, resulting from the broken bonds between boron and chlorine on SubPc with presence of NPB. These gap states are attributed to the improvement of device performance.
Solution-processed cavity and slow-light quantum electrodynamics in near-infrared silicon photonic crystals
Authors: Bose R. , McMillan J. F. , Gao J. , Wong C. W.
Published: September 2009

We demonstrate enhanced emission of solution-processed sparse lead sulfide quantum dots (QDs) coupled to confined as well as propagating modes in silicon photonic crystals at near-infrared communications wavelengths. In the cavity case, by using cold-cavity characterization using on-board waveguides or cross-polarization techniques, we show that the coupled QD lineshape is identical to the cold-cavity spectra. For the photonic crystal waveguides (PhCWGs), we use transmission spectra for the PhCWG as well as three-dimensional finite difference time domain techniques to validate enhancements due to the propagating mode. The observation of room-temperature quantum electrodynamics using postfabrication QD integration techniques is promising for further studies.
Highly efficient nondoped green organic light-emitting devices based on a substituted triphenylpyridine derivative
Authors: Li Na , Lai Shiu-Lun , Wang Pengfei , Teng Feng , Liu Zengtao , Lee Chun-Sing , Lee Shuit-Tong
Published: September 2009

Highly efficient nondoped green organic light-emitting devices based on a triphenylpyridine derivative, 4-[4-(dimethylamino)phenyl]-2,6-diphenylnicotinonitrile (NPDPN), were fabricated and characterized. The double-organic-layer device with a structure of ITO/α-napthylphenylbiphenyl diamine /NPDPN/LiF/Al, in which NPDPN was used as both the emitter and the electron transporter, exhibits a green emission with Commission Internationale de L'Eclairage (CIE) coordinates of (0.23,0.52) and a power efficiency of 5.5 lm/W. The result is much better than that of similarly structured device based on tris(8-hydroxyquinoline)aluminum. Furthermore, a high current efficiency of 8.4 cd/A was achieved with an optimized device configuration.
First-principle study on the magnetic properties of six potential half-metallic ferromagnets: C-doped alkaline-earth chalcogenides
Authors: Liu J. , Chen L. , Dong H. -N. , Zheng R. -L.
Published: September 2009

Six half-metallic ferromagnets with NaCl structure, X4CY3 (X=Mg, Ca, and Sr and Y=O and S) are predicted by the first principle calculations based on the density functional theory. The supercell magnetic moments of these ferromagnets are all integer 2.0μB, which are one of important characters of half-metallic ferromagnets. Our calculations indicate that X4CY3 have wide spin gap and potentially have high Curie temperature. C-doping results in the spin-polarization and half-metallicity of these alkaline-earth chalcogenides. The main reason is that there are sp hybridized orbitals in X4CY3, and two outer-shell s-electrons of alkaline-earth ions enter into sp hybridized orbitals in parallel.
High energy terahertz emission from two-color laser-induced filamentation in air with pump pulse duration control
Authors: Wang Tie-Jun , Chen Yanping , Marceau Claude , Théberge Francis , Châteauneuf Marc , Dubois Jacques , Chin See Leang
Published: September 2009

Two-color laser-induced femtosecond filamentation was employed to generate high energy terahertz emission in air with high energy pump. By controlling the pump pulse duration, more than four times enhancement in terahertz pulse energy has been obtained when compared with a Fourier transform-limited pump. Multiple filaments’ dynamics might be responsible for the terahertz enhancement. Superbroadband terahertz pulse with energy up to 2 μJ was generated using loose focusing condition, while the maximum terahertz pulse energy in the frequency range below 5.5 THz was around 60 nJ.
Digital soil class mapping using legacy soil profile data: a comparison of a genetic algorithm and classification tree approach
Authors: Nelson M. A. , Odeh I. O. A.
Published: September 2009

Digital soil class mapping (DSCM) provides a means of meeting the growing global demand for soil information. The search for optimal models for digital soil class mapping to take advantage of increasing availability of ancillary information, such as gamma radiometric data, is ongoing. One of the novel approaches to DSCM is based on genetic algorithms, which provide predictive function for DSCM. This paper aims: to develop a scheme for implementing genetic algorithms for rule-set production (GARP) in digital soil class mapping; to compare the performance of GARP and classification tree model (CT); and to evaluate the usefulness of gamma radiometrics as a predictor for DSCM of legacy soil data. We first collated the legacy soil class data from databases of soil profiles and the associated ancillary data from disparate sources. We then created a 200-m resolution DSCM based on the Australian Soil Classification, for the Namoi catchment in north-western New South Wales, using GARP based on the general scorpan-sspfe model and compared the GARP performance with the widely used CT model. Elevation, terrain attributes, magnetic survey, land use, NDVI, and, where available, radiometric data were used as the ancillary variables. In this implementation, inclusion of radiometric data in either of the prediction models significantly improved the classification accuracy and the resulting DSCM. Based on various classification and prediction performance measures, GARP was shown to be outperformed by the CT. We conclude that GARP needs further improvement for its full potential to be realised for digitally mapping soil classes.
An expert system to predict intricate saline - sodic subsoil patterns in upland South Australia
Authors: Thomas M. , Fitzpatrick R. W. , Heinson G. S.
Published: September 2009

Digital soil mapping (DSM) offers apparent benefits over more labour-intensive and costly traditional soil survey. Large cartographic scale (e.g. 1 : 10 000 scale) soil maps are rare in Australia, especially in agricultural areas where they are needed to support detailed land evaluation and targeted land management decisions. We describe a DSM expert system using environmental correlation that applies a priori knowledge from a key area (128 ha) soil–landscape with a regionally repeating toposequence to predict the distribution of saline–sodic subsoil patterns in the surrounding upland farming region (2275 ha) in South Australia.
Our predictive framework comprises interrelated and iterative steps, including: (i) consolidating a priori knowledge of the key area soil–landscape; (ii) refining existing mentally held and graphic soil–landscape models; (iii) selecting suitable environmental covariates compatible with geographic information systems (GIS) by interrogation via 3D visualisation using a GIS; (iv) transforming the existing soil–landscape models to a computer model; (v) applying the computer model to the environmental variables using the expert system; (vi) performing the predictive mapping; and (vii) validation. The environmental covariates selected include: digital terrain attributes of slope gradient, topographic wetness index and plan curvature, and airborne gamma-radiometric K%. We apply selected soil profile physiochemical data from a prior soil survey to validate mapping. Results showed that we correctly predicted the saline–sodic subsoils in 10 of 11 reference profiles in the region.
Structural organization of Weibel-Palade bodies revealed by cryo-EM of vitrified endothelial cells
Authors: Berriman John A. , Li Sam , Hewlett Lindsay J. , Wasilewski Sebastian , Kiskin Fedir N. , Carter Tom , Hannah Matthew J. , Rosenthal Peter B.
Published: September 2009

In endothelial cells, the multifunctional blood glycoprotein von Willebrand Factor (VWF) is stored for rapid exocytic release in specialized secretory granules called Weibel-Palade bodies (WPBs). Electron cryomicroscopy at the thin periphery of whole, vitrified human umbilical vein endothelial cells (HUVECs) is used to directly image WPBs and their interaction with a 3D network of closely apposed membranous organelles, membrane tubules, and filaments. Fourier analysis of images and tomographic reconstruction show that VWF is packaged as a helix in WPBs. The helical signature of VWF tubules is used to identify VWF-containing organelles and characterize their paracrystalline order in low dose images. We build a 3D model of a WPB in which individual VWF helices can bend, but in which the paracrystalline packing of VWF tubules, closely wrapped by the WPB membrane, is associated with the rod-like morphology of the granules.
SH3TC2/KIAA1985 protein is required for proper myelination and the integrity of the node of Ranvier in the peripheral nervous system
Authors: Arnaud Estelle , Zenker Jennifer , de Preux Charles Anne-Sophie , Stendel Claudia , Roos Andreas , Médard Jean-Jacques , Tricaud Nicolas , Kleine Henning , Luscher Bernhard , Weis Joachim , Suter Ueli , Senderek Jan , Chrast Roman
Published: September 2009

Charcot–Marie–Tooth disease type 4C (CMT4C) is an early-onset, autosomal recessive form of demyelinating neuropathy. The clinical manifestations include progressive scoliosis, delayed age of walking, muscular atrophy, distal weakness, and reduced nerve conduction velocity. The gene mutated in CMT4C disease,
SH3TC2
/
KIAA1985
, was recently identified; however, the function of the protein it encodes remains unknown. We have generated knockout mice where the first exon of the
Sh3tc2
gene is replaced with an enhanced GFP cassette. The
Sh3tc2

Δ
Ex1
/Δ
Ex1

knockout animals develop progressive peripheral neuropathy manifested by decreased motor and sensory nerve conduction velocity and hypomyelination. We show that
Sh3tc2
is specifically expressed in Schwann cells and localizes to the plasma membrane and to the perinuclear endocytic recycling compartment, concordant with its possible function in myelination and/or in regions of axoglial interactions. Concomitantly, transcriptional profiling performed on the endoneurial compartment of peripheral nerves isolated from control and
Sh3tc2

Δ
Ex1
/Δ
Ex1

animals uncovered changes in transcripts encoding genes involved in myelination and cell adhesion. Finally, detailed analyses of the structures composed of compact and noncompact myelin in the peripheral nerve of
Sh3tc2

Δ
Ex1
/Δ
Ex1

animals revealed abnormal organization of the node of Ranvier, a phenotype that we confirmed in CMT4C patient nerve biopsies. The generated
Sh3tc2
knockout mice thus present a reliable model of CMT4C neuropathy that was instrumental in establishing a role for Sh3tc2 in myelination and in the integrity of the node of Ranvier, a morphological phenotype that can be used as an additional CMT4C diagnostic marker.
The interwinding nature of protein–protein interfaces and its implication for protein complex formation
Authors: Yura Kei , Hayward Steven
Published: September 2009

Motivation: Structural features at protein–protein interfaces can be studied to understand protein–protein interactions. It was noticed that in a dataset of 45 multimeric proteins the interface could either be described as flat against flat or protruding/interwound. In the latter, residues within one chain were surrounded by those in other chains, whereas in the former they were not.

Results: A simple method was developed that could distinguish between these two types with results that matched those made by a human annotator. Applying this automatic method to a large dataset of 888 structures, chains at interfaces were categorized as non-surrounded or surrounded. It was found that the surrounded set had a significantly lower folding tendency using a sequence based measure, than the non-surrounded set. This suggests that before complexation, surrounded chains are relatively unstable and may be involved in ‘fly-casting’. This is supported by the finding that terminal regions are overrepresented in the surrounded set.

Availability:  http://cib.cf.ocha.ac.jp/DACSIS/

Contact:  yura.kei@ocha.ac.jp; sjh@cmp.uea.ac.uk

Supplementary information:  Supplementary data are available at Bioinformatics online.
A Clinical Study of the Pulse Wave Characteristics at the Three Pulse Diagnosis Positions of Chon, Gwan and Cheok
Authors: Jeon Young J. , Kim Jaeuk U. , Lee Hae J. , Lee Jeon , Ryu Hyun H. , Lee Yu J. , Kim Jong Y.
Published: September 2009

In this work, we analyze the baseline, signal strength, aortic augmentation index (AIx), radial AIx, time to reflection and P_T2 at Chon, Gwan, and Cheok, which are the three pulse diagnosis positions in Oriental medicine. For the pulse measurement, we used the SphygmoCor apparatus, which has been widely used for the evaluation of the arterial stiffness at the aorta. By two‐way repeated measures analysis of variance, we tested two independent measurements for repeatability and investigated their mean differences among Chon, Gwan and Cheok. To characterize further the parameters that were shown to be different between each palpation position, we carried out Duncan′s test for the multiple comparisons. The baseline and signal strength were statistically different (P< .05) among Chon, Gwan and Cheok, respectively, which supports the major hypothesis of Oriental medicine that all of the three palpation positions contain different clinical information. On the other hand, aortic AIx and time to reflection were found to be statistically different between Chon and the others, and radial AIx and P_T2 did not show any difference between pulse positions. In the clinical sense, however, the aortic AIx at each palpation position was found to fall within the 90% confidence interval of normal arterial compliance. The results of the multiple comparisons indicate that the parameters of arterial stiffness were independent of the palpation positions. This work is the first attempt to characterize quantitatively the pulse signals at Chon, Gwan and Cheok with some relevant parameters extracted from the SphygmoCor apparatus.
Significance of anaemia in patients with advanced heart failure receiving long‐term mechanical circulatory support
Authors: Vrtovec Bojan , Radovancevic Rajko , Delgado Reynolds M. , Radovancevic Branislav , Bracey Arthur W. , Gregoric Igor D. , Frazier O.H.
Published: September 2009

Aims

The aim of this study was to analyse the prognostic impact of anaemia in patients receiving long‐term left ventricular assist device (LVAD) support.

Methods and results

We reviewed the data of 65 consecutive patients who underwent LVAD support for at least 6 months. Anaemia was defined as haemoglobin levels <12.0 g/dL. Follow‐up was performed 15 months after implantation. Anaemia was present in 30/65 patients (46%) after 6 months of LVAD support. Anaemic patients had higher levels of pre‐implant creatinine (1.8 ± 0.8 vs. 1.4 ± 0.5 mg/dL; P = 0.04). The presence of anaemia after 6 months correlated with higher levels of creatinine and blood urea nitrogen and lower levels of albumin. Multivariate Cox proportional hazards regression analysis revealed that levels of haemoglobin <12 g/dL [risk ratio (RR), 8.94; 95% confidence interval (CI), 1.09–73.01; P = 0.04], creatinine >1.4 mg/dL (RR, 5.39; 95% CI, 1.78–16.30; P = 0.003), and albumin <1.5 g/L (RR, 3.23; 95% CI, 1.10–9.51; P = 0.03) were associated with all‐cause mortality at 15 months. Long‐term survival evaluated by Kaplan–Meier analysis was two times higher in non‐anaemic patients after 6 months of LVAD support than in anaemic patients (P = 0.01).

Conclusion

Anaemia is related to adverse outcomes in patients receiving prolonged LVAD support.
Brain natriuretic peptide for the prediction of sudden cardiac death and ventricular arrhythmias: a meta‐analysis
Authors: Scott Paul A. , Barry James , Roberts Paul R. , Morgan John M.
Published: September 2009

Aims

The risk stratification of patients for sudden cardiac death (SCD) remains a challenge. Brain natriuretic peptide (BNP) predicts overall mortality in heart disease but it is unclear how well it predicts SCD. We therefore performed a meta‐analysis of studies evaluating the accuracy of BNP to predict SCD and ventricular arrhythmias (VA).

Methods and results

Electronic databases and published bibliographies were systematically searched (1984–2008). We found 14 studies that met our inclusion criteria. Six studies (3543 patients) evaluated BNP to predict SCD in patients without implantable cardioverter defibrillators (ICDs) across a wide range of populations. A raised BNP predicted SCD with a relative risk of 3.68 [95% confidence interval (CI) 1.90, 7.14]. Eight studies (1047 patients) evaluated BNP to predict the occurrence of VA in patients with ICDs. A raised BNP predicted the occurrence of VA with a relative risk of 2.54 (95% CI 1.87, 3.44).

Conclusion

The measurement of BNP has significant value in predicting SCD and VA. However, the benefit of BNP testing in addition to other risk stratification tests is unclear and BNP needs to be evaluated prospectively in combination with other complementary risk stratification tools.
Plasma B‐type natriuretic peptide and anti‐inflammatory cytokine interleukin‐10 levels predict adverse clinical outcome in chronic heart failure patients with depressive symptoms: a 1‐year follow‐up study
Authors: Parissis John T. , Farmakis Dimitrios , Nikolaou Maria , Birmpa Dionysia , Bistola Vassiliki , Paraskevaidis Ioannis , Ikonomidis Ignatios , Gaitani Stavroula , Venetsanou Koula , Filippatos Gerasimos , Kremastinos Dimitrios Th.
Published: September 2009

Aims

To assess the prognostic value of a wide spectrum of neurohormonal and inflammatory markers along with functional status and exercise capacity, in hospitalized chronic heart failure (CHF) patients with depressive symptoms.

Methods and results

A total of 300 consecutive hospitalized CHF patients were screened for depressive symptomatology using the Zung self‐rated depression scale (SDS). Patients with depressive symptoms (Zung SDS ≥40) underwent a 6 min walking test, and evaluation of left ventricular ejection fraction, B‐type natriuretic peptide (BNP), and plasma inflammatory/anti‐inflammatory factors [interleukin (IL)‐6, IL‐10, tumour necrosis factor‐α, soluble intercellular adhesion molecule‐1, and vascular cell adhesion molecule‐1]. Patients were subsequently followed for up to 1 year for major adverse cardiovascular events (MACE, death or hospitalization due to cardiovascular causes). One hundred and fourteen patients (38%) had a Zung SDS ≥40. One‐year event‐free survival of these patients was 19% (mean ± SE, 150 ± 12 days). In multivariate analysis, only BNP (HR = 1.001, P = 0.002) and IL‐10 (HR = 0.864, P = 0.049) were independent predictors of MACE. Using receiver operator characteristics analysis‐derived cut‐offs, a BNP value of 290 pg/mL predicted MACE with 86% sensitivity and 69% specificity, whereas an IL‐10 value of 5 pg/mL predicted MACE with 61% sensitivity and 78% specificity. Event‐free survival differed significantly between patients with BNP < 290 pg/mL and IL‐10 > 5 pg/mL (261 ± 44 days) and those with BNP > 290 pg/mL and IL‐10 < 5 pg/mL (79 ± 11 days, P = 0.0001).

Conclusion

Neurohormonal activation and defective anti‐inflammatory properties are independent predictors of long‐term outcome in hospitalized CHF patients with depressive symptoms.
Mass Critical Care: Pediatric Considerations in Extending and Rationing Care in Public Health Emergencies
Authors: Kanter Robert K. , Cooper Arthur
Published: September 2009

This article applies developing concepts of mass critical care (MCC) to children. In public health emergencies (PHEs), MCC would improve population outcomes by providing lifesaving interventions while delaying less urgent care. If needs exceed resources despite MCC, then rationing would allocate interventions to those most likely to survive with care. Gaps between estimated needs and actual hospital resources are worse for children than adults. Clear identification of pediatric hospitals would facilitate distribution of children according to PHE needs, but all hospitals must prepare to treat some children. Keeping children with a family member and identifying unaccompanied children complicate PHE regional triage. Pediatric critical care experts would teach and supervise supplemental providers. Adapting nearly equivalent equipment compensates for shortages, but there is no substitute for age-appropriate resuscitation masks, IV/suction catheters, endotracheal/gastric/chest tubes. Limitations will be encountered using adult ventilators for infants. Temporary manual bag valve ventilation and development of shared ventilators may prolong survival until the arrival of ventilator stockpiles. To ration MCC to children most likely to survive, the Pediatric Index of Mortality 2 score meets the criteria for validated pediatric mortality predictions. Policymakers must define population outcome goals in regard to lives saved versus life-years saved. (Disaster Med Public Health Preparedness. 2009;3(Suppl 2):S166–S171)
Preventing the Soldiers of Health Care From Becoming Victims on the Pandemic Battlefield: Respirators or Surgical Masks as the Armor of Choice
Authors: Radonovich Lewis J. , Perl Trish M. , Davey Victoria , Cohen Howard
Published: September 2009

The respiratory protective equipment necessary to protect health care workers from the novel swine-origin influenza A (H1N1) virus is not known. The knowledge gap created by this unanswered question has caused substantial debate and controversy on a global scale, leading public health organizations to feel pressured into issuing decisive recommendations despite a lack of supportive data. Changes in clinical practice caused by public health guidance during such high-profile events can be expected to establish a new standard of care. Also possible is an unforeseen gradual transition to widespread N95 respirator use, driven by public health pressures instead of science, for all outbreaks of influenza or influenza-like illness. Therefore, public health organizations and other influential institutions should take care to avoid making changes to established practice standards, if possible, unless these changes are bolstered by sound scientific evidence. Until definitive comparative effectiveness clinical trials are conducted, the answer to this question will continue to remain elusive. In the meantime, relying on ethical principles that have been substantiated over time may help guide public health and clinical decisions. (Disaster Med Public Health Preparedness. 2009;3(Suppl 2):S203–S210)
Frank Reginald Nunes Nabarro MBE. 7 March 1916 — 20 July 2006
Authors: Brown L. M.
Published: September 2009

Frank Nabarro is remembered as one of the great pioneers who developed the theory of dislocations in solids and thereby strikingly advanced understanding of the mechanical behaviour of metals. In two crucial areas he addressed the problem of the stress required to initiate plastic flow: first in metals alloyed to produce precipitates (precipitation hardening), and second in pure crystals of all types in which dislocation movement is impeded only by the intrinsic lattice resistance (Peierls–Nabarro stress). He predicted the slow creep of crystals at high temperature by the movement of single vacancies (Nabarro–Herring creep), a universal phenomenon of great engineering importance. Working from the University of Witwatersrand he edited
Dislocations in solids
, a series of review articles that continue to be essential keys to the huge unruly literature on dislocations. In South Africa he had an important role not only in developing solid state physics but also in promoting educational opportunities for students of all races, particularly in planning university expansion to accommodate the much larger student numbers expected after the end of apartheid, a policy that he vehemently opposed.
Studies of a Novel Cysteine Sulfoxide Lyase fromPetiveria alliacea: The First Heteromeric Alliinase
Authors: Musah Rabi A. , He Quan , Kubec Roman , Jadhav Abhijit
Published: September 2009

A novel alliinase (EC 4.4.1.4) was detected and purified from the roots of the Amazonian medicinal plant Petiveria alliacea. The isolated enzyme is a heteropentameric glycoprotein composed of two α-subunits (68.1 kD each), one β-subunit (56.0 kD), one γ-subunit (24.8 kD), and one δ-subunit (13.9 kD). The two α-subunits are connected by a disulfide bridge, and both α- and β-subunits are glycosylated. The enzyme has an isoelectric point of 4.78 and pH and temperature optima of 8.0 and approximately 52°C, respectively. Its activation energy with its natural substrate S-benzyl-l-cysteine sulfoxide is 64.6 kJ mol−1. Kinetic studies showed that both Km and Vmax vary as a function of substrate structure, with the most preferred substrates being the naturally occurring P. alliacea compounds S-benzyl-l-cysteine sulfoxide and S-2-hydroxyethyl-l-cysteine sulfoxide. The alliinase reacts with these substrates to produce S-benzyl phenylmethanethiosulfinate and S-(2-hydroxyethyl) 2-hydroxyethanethiosulfinate, respectively.
Extensive Structural Renovation of Retrogenes in the Evolution of the Populus Genome
Authors: Zhu Zhenglin , Zhang Yong , Long Manyuan
Published: September 2009

Retroposition, as an important copy mechanism for generating new genes, was believed to play a negligible role in plants. As a representative dicot, the genomic sequences of Populus (poplar; Populus trichocarpa) provide an opportunity to investigate this issue. We identified 106 retrogenes and found the majority (89%) of them are associated with functional signatures in sequence evolution, transcription, and (or) translation. Remarkably, examination of gene structures revealed extensive structural renovation of these retrogenes: we identified 18 (17%) of them undergoing either chimerization to form new chimerical genes and (or) intronization (transformation into intron sequences of previously exonic sequences) to generate new intron-containing genes. Such a change might occur at a high speed, considering eight out of 18 such cases occurred recently after divergence between Arabidopsis (Arabidopsis thaliana) and Populus. This pattern also exists in Arabidopsis, with 15 intronized retrogenes occurring after the divergence between Arabidopsis and papaya (Carica papaya). Thus, the frequency of intronization in dicots revealed its importance as a mechanism in the evolution of exon-intron structure. In addition, we also examined the potential impact of the Populus nascent sex determination system on the chromosomal distribution of retrogenes and did not observe any significant effects of the extremely young sex chromosomes.
Knockdown ofCELL DIVISION CYCLE16Reveals an Inverse Relationship between Lateral Root and Nodule Numbers and a Link to Auxin inMedicago truncatula
Authors: Kuppusamy Kavitha T. , Ivashuta Sergey , Bucciarelli Bruna , Vance Carroll P. , Gantt J. Stephen , VandenBosch Kathryn A.
Published: September 2009

The postembryonic development of lateral roots and nodules is a highly regulated process. Recent studies suggest the existence of cross talk and interdependency in the growth of these two organs. Although plant hormones, including auxin and cytokinin, appear to be key players in coordinating this cross talk, very few genes that cross-regulate root and nodule development have been uncovered so far. This study reports that a homolog of CELL DIVISION CYCLE16 (CDC16), a core component of the Anaphase Promoting Complex, is one of the key mediators in controlling the overall number of lateral roots and nodules. A partial suppression of this gene in Medicago truncatula leads to a decrease in number of lateral roots and a 4-fold increase in number of nodules. The roots showing lowered expression of MtCDC16 also show reduced sensitivity to phytohormone auxin, thus providing a potential function of CDC16 in auxin signaling.