bluuebunny/crossref_metadata_2025 huggingface dataset:
Systems to support health technology assessment (HTA) in Member States of the European Union with limited institutionalization of HTA
Authors: Moharra Montse , Espallargues Mireia , Kubesch Nadine , Estrada Maria-Dolors , Parada Antoni , Vondeling Hindrik , Lo Scalzo Alessandra , Cristofides Stelios , Turk Eva , Raab Martin
Published: December 2009

Objectives: The aim of this study was to support health technology assessment (HTA) capacity building in Member States of the European Union with limited experience or without institutionalized HTA. The main output is a Handbook on HTA Capacity Building.

Methods: The methods used were worldwide surveys of (i) HTA organizations, (ii) information management units, and (iii) HTA educational programs. The results of two surveys (i & ii) were combined with expert opinion to produce the Handbook on HTA Capacity Building.

Results:Survey of HTA organizations (n = 41, response rate 35 percent). Most of the organizations were established by the government (61 percent), and all were not-for-profit. Working on HTA (80.5 percent) and doing research (63.4 percent) were the main lines of activity. Survey on information management units (n = 23, response rate 23 percent). Most (74.2 percent) of the responding HTA agencies reported having personnel dedicated to HTA information services. Survey on HTA educational programs (n = 48, response rate 60 percent). In total, nine Master of Science (MSc) programs were identified (three MSc in HTA and six MSc in HTA-related areas). Handbook on HTA Capacity Building. A group of twenty experts from thirteen countries developed the handbook. It consists of nine chapters focusing on HTA institutional development (structural setup, work processes, and visibility).

Conclusions: Setting up organizational structures and establishing effective HTA programs that guide key policy decisions is a challenging task. There are no standard models or pathways. “One size fits all” is not a useful principle because of the wide systemic and cultural differences between countries. The Handbook on HTA Capacity Building includes approaches for overall institutional development, especially in formulating objectives, setting up structures, and defining work processes.
European network for Health Technology Assessment, EUnetHTA: Planning, development, and implementation of a sustainable European network for Health Technology Assessment
Authors: Kristensen Finn Børlum , Mäkelä Marjukka , Neikter Susanna Allgurin , Rehnqvist Nina , Håheim Lise Lund , Mørland Berit , Milne Ruairidh , Nielsen Camilla Palmhøj , Busse Reinhard , Lee-Robin Sun Hae , Wild Claudia , Espallargues Mireia , Chamova Julia
Published: December 2009

Objectives: The European network on Health Technology Assessment (EUnetHTA) aimed to produce tangible and practical results to be used in the various phases of health technology assessment and to establish a framework and processes to support this. This article presents the background, objectives, and organization of EUnetHTA, which involved a total of sixty-four partner organizations.

Methods: Establishing an effective and sustainable structure for a transnational network involved many managerial, policy, and methodological tools, according to the objective of each task or Work Package. Transparency in organization, financial transactions, and decision making was a key principle in the management of the Project as was the commitment to appropriately involve stakeholders.

Results: EUnetHTA activities resulted in a clear management and governance structure, efficient partnership, and transnational cooperation. The Project developed a model for sustainable continuation of the EUnetHTA Collaboration.

Conclusions: The EUnetHTA Project achieved its goals by producing a suite of practical tools, a strong network, and plans for continuing the work in a sustainable EUnetHTA Collaboration that facilitates and promotes the use of HTA at national and regional levels. Responsiveness to political developments in Europe should be balanced with maintaining a high level of ambition to promote independent, evidence-based information and well-tested tools for best practice based on a strong network of HTA institutions.
The East–West Health Divide in Europe: Growing and Shifting Eastwards
Authors: Vågerö Denny
Published: December 2009

Over a four-decade long period, a health gap has opened up between European countries, in particular along the East/West dimension. One could speak of a European health divide. The divide is growing larger and, at the same time, shifting eastwards, leaving countries such as Russia, Ukraine, Belarus and Moldova at an increasing health disadvantage. Health inequalities, or differences between social classes, within European countries also seem to have been growing for the last couple of decades. Those countries that were previously led by communist regimes today show larger health inequalities than do countries in Western Europe. The countries that were once part of the Soviet Union demonstrate the most alarming health trends, with large segments of the population actually experiencing falling life expectancies. Reducing global and European health inequalities so that the health chances of a newborn child are not dependent on which country and social class he or she is born in, is a truly formidable task, which implies an entirely new way of seeing human development.
Glider observations of kinematics in a Gulf of Alaska eddy
Authors: Martin J. P. , Lee C. M. , Eriksen C. C. , Ladd C. , Kachel N. B.
Published: December 2009

The depth‐radial structure of a Gulf of Alaska (GoA) eddy is investigated using observations from an autonomous winged buoyancy‐driven glider, drifters, and satellite altimeters. The eddy formed when Sitka and Yakutat eddies merged in June 2005. Sitka and Yakutat eddies form in the northeastern GoA and travel westward carrying anomalous energy, temperature, and chemical properties. The glider crossed the eddy seven times from mid‐August to late October 2005. A temperature maximum, at 130 m depth near the eddy's center, is indicative of coastal water. The strongest azimuthal current is 0.35 m s−1, occurring at 270 m depth and 17.5 km radius. The eddy's Rossby (Burger) number is 0.16 (0.47). Using a model with nonzero constant potential vorticity anomaly only within each depth's radius of strongest current, a function is fit to azimuthal current. The fit explains a large percentage of the current's radial variance, with a squared correlation coefficient of ≥0.9 at the depths of strongest current (270 m) and weakest stratification (360 m). Temporal trends in azimuthal volume transport rate and depth mean potential vorticity are not observed during the glider survey.
U‐Pb ages of detrital zircons in Pacheco Pass metagraywackes: Sierran‐Klamath source of mid‐Cretaceous and Late Cretaceous Franciscan deposition and underplating
Authors: Ernst W. G. , Martens Uwe , Valencia Victor
Published: December 2009

Using laser ablation ICP‐MS techniques, U‐Pb ages are reported for 338 detrital zircons separated from four Franciscan metagraywacke samples from imbricate thrust sheets cropping out in the Pacheco Pass area, east central California Coast Ranges. Structurally higher slabs are clastic quartz ± albite‐bearing rocks typified by neoblastic lawsonite + jadeitic pyroxene; the lowest exposed slab lacks jadeitic pyroxene but contains traces of newly grown pumpellyite and lawsonite in addition to abundant quartz + albite. Studied specimens contain moderate amounts of phengite + titanite ± chlorite, stilpnomelane, carbonate, iron oxides, rock fragments, and carbonaceous matter. These Diablo Range clastic sediments were deposited in mid‐Cretaceous and Late Cretaceous time. The highest allochthon, unit I, was deposited after ∼102 Ma, unit IV was deposited after ∼90–102 Ma, and unit V was deposited after ∼86 Ma. Metagraywacke depositional‐accretionary ages within slab IV young upward, but ages of the slabs decrease progressively downward. In the four‐sample aggregate, most zircons have igneous ages falling in the 135–170 Ma range, with a smaller population at 85–120 Ma. The rocks contain rare zircons of Middle Proterozoic–Late Archean ages. A minor source in northern California and NW Nevada seems likely for the Pacheco Pass metagraywackes, but the Sierran‐Klamath calcalkaline arc provided most of the clastic debris. Judging by the volcanic nature of lithic clasts in these Eastern Belt metagraywackes, and because massive Sierran plutonism occurred at ∼85–120 Ma, the abundant 135–170 Ma zircons probably were derived chiefly from the eroding comagmatic volcanic arc rather than from the less voluminous Jurassic arc plutons.
Correlating geochemistry, tectonics, and volcanic volume along the Central American volcanic front
Authors: Bolge Louise L. , Carr Michael J. , Milidakis Katherine I. , Lindsay Fara N. , Feigenson Mark D.
Published: December 2009

The Central American volcanic front consists of several distinct volcanic lineaments or segments, separated by right steps and/or changes in strike. Each volcanic line is rotated slightly counterclockwise from the strike of the inclined seismic zone. Right stepping volcanic lines, oblique to the strike of the slab, create a sawtooth pattern in the depth to the slab. Zr/Nb is the first geochemical signature with consistent large offsets at the right steps in the volcanic front. Moreover, Zr/Nb mirrors the sawtooth variation in depth to the slab; within a segment it increases from SE to NW, and at the right steps, separating segments, it abruptly decreases. Unfortunately, there is no simple negative correlation between Zr/Nb and depth to the slab because Zr/Nb also has a regional variation, similar to previously documented regional variations in slab tracers in Central America (e.g., Ba/La, U/Th, and 87Sr/86Sr). Within a segment, Zr/Nb decreases with increasing depth to slab. This can be explained in two ways: a Nb retaining mineral, e.g., amphibole, in the subducting slab is breaking down gradually with increasing depth causing more Nb to be released and consequently a smaller Nb depletion in deeper melts; alternatively, all melts have the same initial Nb depletion which is then diluted by acquiring Nb from the surrounding mantle wedge as melts rise and react. Deeper melts have longer paths and therefore more reaction with the mantle wedge diluting the initial Nb depletion. Within each volcanic segment there is variation in eruptive volume. The largest volcanoes generally occur in the middle of the segments, and the smaller volcanoes tend to be located at the ends. Connecting the largest volcanoes in each segment suggests an axis of maximum productivity. This is likely the surface projection of the center of the melt aggregation zone. The largest volcanoes tap the entire melt zone. Those with shallow depths to the slab tap just the front part of the melt zone and have very large Nb depletions. Those at greater depths tap the back part of the melt zone and have much smaller Nb depletions.
The science of online dating
Authors: Frazzetto Giovanni
Published: December 2009

Would Romeo and Juliet have had a happier ending if they had been assessed for genetic compatibility? Giovanni Frazzetto explores some of the reasons why science may yet play an important role in the pursuit of love.
Total synthesis of (±)-aspercyclide A and its C19 methyl ether
Authors: Carr James L. , Offermann Daniel A. , Holdom Mary D. , Dusart Philip , White Andrew J. P. , Beavil Andrew J. , Leatherbarrow Robin J. , Lindell Stephen D. , Sutton Brian J. , Spivey Alan C.
Published: December 2009

The total syntheses of (±)-aspercyclide A (1) and its C19 methyl ether derivative (15a) are described. ELISA studies show that both compounds display comparable antagonist activity against the IgE–FcεRI protein–protein interaction.
Euglena gracilisascorbate peroxidase forms an intramolecular dimeric structure: its unique molecular characterization
Authors: Ishikawa Takahiro , Tajima Naoko , Nishikawa Hitoshi , Gao Yongshun , Rapolu Madhusudhan , Shibata Hitoshi , Sawa Yoshihiro , Shigeoka Shigeru
Published: December 2009

Euglena gracilis lacks a catalase and contains a single APX (ascorbate peroxidase) and enzymes related to the redox cycle of ascorbate in the cytosol. In the present study, a full-length cDNA clone encoding the Euglena APX was isolated and found to contain an open reading frame encoding a protein of 649 amino acids with a calculated molecular mass of 70.5 kDa. Interestingly, the enzyme consisted of two entirely homologous catalytic domains, designated APX-N and APX-C, and an 102 amino acid extension in the N-terminal region, which had a typical class II signal proposed for plastid targeting in Euglena. A computer-assisted analysis indicated a novel protein structure with an intramolecular dimeric structure. The analysis of cell fractionation showed that the APX protein is distributed in the cytosol, but not the plastids, suggesting that Euglena APX becomes mature in the cytosol after processing of the precursor. The kinetics of the recombinant mature FL (full-length)-APX and the APX-N and APX-C domains with ascorbate and H2O2 were almost the same as that of the native enzyme. However, the substrate specificity of the mature FL-APX and the native enzyme was different from that of APX-N and APX-C. The mature FL-APX, but not the truncated forms, could reduce alkyl hydroperoxides, suggesting that the dimeric structure is correlated with substrate recognition. In Euglena cells transfected with double-stranded RNA, the silencing of APX expression resulted in a significant increase in the cellular level of H2O2, indicating the physiological importance of APX to the metabolism of H2O2.
Pericellular activation of hepatocyte growth factor by the transmembrane serine proteases matriptase and hepsin, but not by the membrane-associated protease uPA
Authors: Owen Kate A. , Qiu Deyi , Alves Juliano , Schumacher Andrew M. , Kilpatrick Lynette M. , Li Jun , Harris Jennifer L. , Ellis Vincent
Published: December 2009

HGF (hepatocyte growth factor) is a pleiotropic cytokine homologous to the serine protease zymogen plasminogen that requires canonical proteolytic cleavage to gain functional activity. The activating proteases are key components of its regulation, but controversy surrounds their identity. Using quantitative analysis we found no evidence for activation by uPA (urokinase plasminogen activator), despite reports that this is a principal activator of pro-HGF. This was unaffected by a wide range of experimental conditions, including the use of various molecular forms of both HGF and uPA, and the presence of uPAR (uPA receptor) or heparin. In contrast the catalytic domains of the TTSPs (type-II transmembrane serine proteases) matriptase and hepsin were highly efficient activators (50% activation at 0.1 and 3.4 nM respectively), at least four orders of magnitude more efficient than uPA. PS-SCL (positional-scanning synthetic combinatorial peptide libraries) were used to identify consensus sequences for the TTSPs, which in the case of hepsin corresponded to the pro-HGF activation sequence, demonstrating a high specificity for this reaction. Both TTSPs were also found to be efficient activators at the cell surface. Activation of pro-HGF by PC3 prostate carcinoma cells was abolished by both protease inhibition and matriptase-targeting siRNA (small interfering RNA), and scattering of MDCK (Madin–Darby canine kidney) cells in the presence of pro-HGF was abolished by inhibition of matriptase. Hepsin-transfected HEK (human embryonic kidney)-293 cells also activated pro-HGF. These observations demonstrate that, in contrast with the uPA/uPAR system, the TTSPs matriptase and hepsin are direct pericellular activators of pro-HGF, and that together these proteins may form a pathway contributing to their involvement in pathological situations, including cancer.
Band 3 Edmonton I, a novel mutant of the anion exchanger 1 causing spherocytosis and distal renal tubular acidosis
Authors: Chu Carmen , Woods Naomi , Sawasdee Nunghathai , Guizouarn Helene , Pellissier Bernard , Borgese Franck , Yenchitsomanus Pa-thai , Gowrishankar Manjula , Cordat Emmanuelle
Published: December 2009

dRTA (distal renal tubular acidosis) and HS (hereditary spherocytosis) are two diseases that can be caused by mutations in the gene encoding the AE1 (anion exchanger 1; Band 3). dRTA is characterized by defective urinary acidification, leading to metabolic acidosis, renal stones and failure to thrive. HS results in anaemia, which may require regular blood transfusions and splenectomy. Mutations in the gene encoding AE1 rarely cause both HS and dRTA. In the present paper, we describe a novel AE1 mutation, Band 3 Edmonton I, which causes dominant HS and recessive dRTA. The patient is a compound heterozygote with the new mutation C479W and the previously described mutation G701D. Red blood cells from the patient presented a reduced amount of AE1. Expression in a kidney cell line showed that kAE1 (kidney AE1) C479W is retained intracellularly. As kAE1 is a dimer, we performed co-expression studies and found that, in kidney cells, kAE1 C479W and G701D proteins traffic independently from each other despite their ability to form heterodimers. Therefore the patient carries one kAE1 mutant that is retained in the Golgi (G701D) and another kAE1 mutant (C479W) located in the endoplasmic reticulum of kidney cells, and is thus probably unable to reabsorb bicarbonate into the blood. We conclude that the C479W mutant is a novel trafficking mutant of AE1, which causes HS due to a decreased cell-surface AE1 protein and results in dRTA due to its intracellular retention in kidney.
Ref2, a regulatory subunit of the yeast protein phosphatase 1, is a novel component of cation homoeostasis
Authors: Ferrer-Dalmau Jofre , González Asier , Platara Maria , Navarrete Clara , Martínez José L. , Barreto Lina , Ramos José , Ariño Joaquín , Casamayor Antonio
Published: December 2009

Maintenance of cation homoeostasis is a key process for any living organism. Specific mutations in Glc7, the essential catalytic subunit of yeast protein phosphatase 1, result in salt and alkaline pH sensitivity, suggesting a role for this protein in cation homoeostasis. We screened a collection of Glc7 regulatory subunit mutants for altered tolerance to diverse cations (sodium, lithium and calcium) and alkaline pH. Among 18 candidates, only deletion of REF2 (RNA end formation 2) yielded increased sensitivity to these conditions, as well as to diverse organic toxic cations. The Ref2F374A mutation, which renders it unable to bind Glc7, did not rescue the salt-related phenotypes of the ref2 strain, suggesting that Ref2 function in cation homoeostasis is mediated by Glc7. The ref2 deletion mutant displays a marked decrease in lithium efflux, which can be explained by the inability of these cells to fully induce the Na+-ATPase ENA1 gene. The effect of lack of Ref2 is additive to that of blockage of the calcineurin pathway and might disrupt multiple mechanisms controlling ENA1 expression. ref2 cells display a striking defect in vacuolar morphogenesis, which probably accounts for the increased calcium levels observed under standard growth conditions and the strong calcium sensitivity of this mutant. Remarkably, the evidence collected indicates that the role of Ref2 in cation homoeostasis may be unrelated to its previously identified function in the formation of mRNA via the APT (for associated with Pta1) complex.
Intonation Contrast in Cantonese Speakers With Hypokinetic Dysarthria Associated With Parkinson’s Disease
Authors: Ma Joan K.-Y. , Whitehill Tara L. , So Susanne Y.-S.
Published: December 2009

Purpose

Speech produced by individuals with hypokinetic dysarthria associated with Parkinson’s disease (PD) is characterized by a number of features including impaired speech prosody. The purpose of this study was to investigate intonation contrasts produced by this group of speakers.

Method

Speech materials with a question–statement contrast were collected from 14 Cantonese speakers with PD. Twenty listeners then classified the productions as either questions or statements. Acoustic analyses of F0, duration, and intensity were conducted to determine which acoustic cues distinguished the production of questions from statements, and which cues appeared to be exploited by listeners in identifying intonational contrasts.

Results

The results show that listeners identified statements with a high degree of accuracy, but the accuracy of question identification ranged from 0.56% to 96% across the 14 speakers. The speakers with PD used similar acoustic cues as nondysarthric Cantonese speakers to mark the question–statement contrast, although the contrasts were not observed in all speakers. Listeners mainly used F0 cues at the final syllable for intonation identification.

Conclusion

These data contribute to the researchers' understanding of intonation marking in speakers with PD, with specific application to the production and perception of intonation in a lexical tone language.
Perception of Wet Vocal Quality in Identifying Penetration/Aspiration During Swallowing
Authors: Groves-Wright Kathy Jean , Boyce Suzanne , Kelchner Lisa
Published: December 2009

Purpose

In the present study, the authors investigated the association between wet vocal quality (WVQ) and prandial material in the larynx during phonation. The presence of such material is indicative of oropharyngeal dysphagia and results from entry of material into the laryngeal vestibule during swallowing. The primary aim of the study was to determine whether clinicians reliably perceive WVQ during phonation when prandial material is in the larynx.

Method

Seventy-eight subjects underwent videofluoroscopic swallow study, and simultaneous recording of time-linked videofluoroscopic and acoustic data was conducted during postswallow phonation. Experienced dysphagia clinicians then rated randomized audio samples for presence or absence of WVQ.

Results

WVQ is not reliably perceived by clinicians when material is present in the larynx in the region of the glottis during phonation, and there is a high degree of interrater variability for perceptual judgments of wetness.

Conclusions

Material in the larynx during phonation may result in multiple voice quality percepts, and even experienced clinicians may not be adept at identifying the perceptual consequences of this. Observation of laryngeal physiology during voicing when material is in the larynx using vocal tract imaging can improve reliability in the identification of wet vocal quality.
Randomized Controlled Trial of Video Self-Modeling Following Speech Restructuring Treatment for Stuttering
Authors: Cream Angela , O’Brian Sue , Jones Mark , Block Susan , Harrison Elisabeth , Lincoln Michelle , Hewat Sally , Packman Ann , Menzies Ross , Onslow Mark
Published: December 2009

Purpose

In this study, the authors investigated the efficacy of video self-modeling (VSM) following speech restructuring treatment to improve the maintenance of treatment effects.

Method

The design was an open-plan, parallel-group, randomized controlled trial. Participants were 89 adults and adolescents who undertook intensive speech restructuring treatment. Post treatment, participants were randomly assigned to 2 trial arms: standard maintenance and standard maintenance plus VSM. Participants in the latter arm viewed stutter-free videos of themselves each day for 1 month.

Results

The addition of VSM did not improve speech outcomes, as measured by percent syllables stuttered, at either 1 or 6 months postrandomization. However, at the latter assessment, self-rating of worst stuttering severity by the VSM group was 10% better than that of the control group, and satisfaction with speech fluency was 20% better. Quality of life was also better for the VSM group, which was mildly to moderately impaired compared with moderate impairment in the control group.

Conclusions

VSM intervention after treatment was associated with improvements in self-reported outcomes. The clinical implications of this finding are discussed.
Kinetics of crack growth in zirconium alloys (I): Temperature dependence of the crack growth rate
Authors: Kim Young S.
Published: December 2009

Delayed hydride cracking (DHC) tests were conducted on a cold-worked Zr–2.5Nb tube with hydrogen at different test temperatures ranging from 100 to 350 °C. Striation spacing corresponding to a critical hydride length increased with temperature, demonstrating that hydride cracking resistance is enhanced with temperature. Nonetheless, the crack growth rate (CGR) had a positive temperature dependence below 300 °C, showing that at temperatures below 300 °C, the CGR is governed by diffusion-controlled hydride growth. At higher temperatures above 300 °C, however, the CGR decreased rapidly, suggesting that the CGR is dictated not by the hydride growth rate but by the hydride cracking rate. This suggestion is evidenced by experiments where the threshold stress intensity factor for DHC or KIH increased sharply above 300 °C.
Dielectric hysteresis, relaxation dynamics, and nonvolatile memory effect in carbon nanotube dispersed liquid crystal
Authors: Basu Rajratan , Iannacchione Germano S.
Published: December 2009

Self-organizing nematic liquid crystals (LCs) impart their orientational order onto dispersed carbon nanotubes (CNTs) and obtain CNT-self-assembly on a macroscopic dimension. The nanotube-long axis, being coupled to the nematic director, enables orientational manipulation via the LC nematic reorientation. Electric-field-induced director rotation of a nematic LC+CNT system is of potential interest due to its possible application as a nanoelectromechanical system. Electric field and temperature dependence of dielectric properties of a LC+CNT composite system have been investigated to understand the principles governing CNT assembly mediated by the LC. In the LC+CNT nematic phase, the dielectric relaxation on removing the applied field follows a single-exponential decay, exhibiting a faster decay response than the pure LC above a threshold field. The observed dielectric behaviors on field cycling in the nematic phase for the composite indicates an electromechanical hysteresis effect of the director field due to the LC-CNT anchoring mechanism. Observations in the isotropic phase coherently combine to confirm the presence of anisotropic pseudonematic domains stabilized by the LC-CNT anchoring energy. These polarized domains maintain local directors and respond to external fields, but do not relax back to the original state on switching the field off, showing nonvolatile memory effect.
Midinfrared filters based on extraordinary optical transmission through subwavelength structured gold films
Authors: Ortuño R. , García-Meca C. , Rodríguez-Fortuño F. J. , Håkansson A. , Griol A. , Hurtado J. , Ayucar J. A. , Bellieres L. , Rodríguez P. J. , López-Royo F. , Martí J. , Martínez A.
Published: December 2009

An experimental study is made of the enhanced optical transmission of nanostructured gold films in the midinfrared region. Results indicate that the excitation of surface plasmon polaritons due to periodicity plays a fundamental role in producing extraordinary optical transmission. The influence of the surrounding claddings, hole shape, and periodicity on the resonance wavelength and the quality factor is investigated. The aim is to use the subwavelength structures as ultracompact optical filters whose spectral features can be easily tuned and scaled. For filter design purposes, the results show that the main parameters affecting the resonance wavelength are the lattice constant and dielectric cladding. The hole shape and size are found to cause transmission enhancement and there is only a small resonance redshift when the hole area is increased. However, a lower quality factor is achieved when the hole area is increased.
Modulating microstructure and magnetic properties of BaFe12O19 thin films by using Pt and yttria stabilized zirconia underlayers
Authors: Li Q. F. , Su X. D. , Li H. , Zhang L. , Liu Z. H. , Zhong H. J.
Published: December 2009

The c-axis oriented barium ferrite thin films were prepared by radio frequency magnetron sputtering on silicon substrates with a metal underlayer Pt (111) as well as an oxide underlayer yttria stabilized zirconia (YSZ). Microstructural studies (scanning electron microscopy, atomic force microscopy, and magnetic force microscopy) showed that the magnetic grains in BaM film have a strong relationship with the grains in the underlayer. The Pt underlayer is more effective in forming micrometer-sized and multidomain magnetic grains, which have high saturation magnetization but small coercivity and remanence of the BaM film. On the contrary, the YSZ underlayer is favorable to obtain nanometer-sized and monodomain magnetic grains, which lead to a slight decrease in saturation magnetization but dramatically increase coercivity and remanence of the BaM film. Hence, with careful selection of underlayer, it is feasible to obtain suitable magnetic grain size and domain structure of BaM films to satisfy special requirements.
Crossbar heterojunction field effect transistors of CdSe:In nanowires and Si nanoribbons
Authors: He Z. B. , Zhang W. J. , Tang Y. B. , Wang H. B. , Cao Y. L. , Song H. S. , Bello I. , Lee C. S. , Lee S. T.
Published: December 2009

Crossbar heterojunction arrays of n-CdSe:In nanowires (NWs) and p-Si nanoribbons (NRs) were built by ac electrical field-directed assembly. The junctions showed significant rectifying characteristics. With the p-Si NRs as gates, the junctions function as junction field effect transistors (JFETs) with high stability and reproducibility in performance. A small variation in gate voltage from −2 to −1 V was demonstrated to manipulate the current in n-CdSe:In NW channels by a factor near 103. The JFETs also showed a subthreshold swing value (67 mV/dec) approaching the theoretical limit (60 mV/dec), suggesting the great application potentials of the junctions in integrated nanoelectronics.
Gate-to-drain capacitance verifying the continuous-wave green laser crystallization n-TFT trapped charges distribution under dc voltage stress
Authors: Hsieh Zhen-Ying , Wang Mu-Chun , Chen Shuang-Yuan , Chen Chih , Huang Heng-Sheng
Published: December 2009

In this work, a metrology was proposed to realize the distribution of fixed oxide trapped charges and grain boundary trapped states. The (continuous-wave green laser crystallization) n-channel thin-film transistors (TFTs) were forced by dc voltage stress, VG=VD. The gate-to-drain capacitance, CGD−VG, with varying frequency of applied small signal was developed. To probe the distribution of these defects, the difference (initial capacitance values minus stressed capacitance values) of CGD−VG with different frequencies was precisely studied.
A theoretical study of the initial oxidation of the GaAs(001)-β2(2×4) surface
Authors: Scarrozza M. , Pourtois G. , Houssa M. , Caymax M. , Stesmans A. , Meuris M. , Heyns M. M.
Published: December 2009

The early stages of the oxidation of the GaAs(001)-β2(2×4) surface are investigated theoretically by ab initio molecular dynamics simulations. An atomistic mechanism of formation of structural defects at the interface is described. The electronic properties of the GaAs/oxide interface are computed and it is found that energy levels within the bandgap are associated with the generated interfacial structural defects. These results provide an atomistic description of the nature of the defects at the origin of the Fermi level pinning in III–V’s as well as the mechanism underlying their generation.
Copolymer solution-based “smart window”
Authors: Gong Xiuqing , Li Jiaxing , Chen Shuyu , Wen Weijia
Published: December 2009

The authors report the design of a prototype smart window based on the phenomenon of the thermally induced aggregation of triblock copolymer poly (ethylene oxide)–poly (propylene oxide)–poly (ethylene oxide) (EPE). Fluorescein isothiocyanate was used to label EPE and study aggregation phenomenon at different temperatures. The cloud point could be tuned by mixing EPE with sodium dodecyl sulfate (SDS) and varying the concentration of the latter. The light transmittance at different temperatures was studied as a function of SDS concentration.
Terahertz metamaterials fabricated by inkjet printing
Authors: Walther Markus , Ortner Alex , Meier Henning , Löffelmann Ute , Smith Patrick J. , Korvink Jan G.
Published: December 2009

Metamaterial layers designed for gigahertz to terahertz (THz)-frequencies have been fabricated by inkjet printing. The spectral response of the structures consisting of periodically arranged metallic split-ring resonators is characterized by THz-time-domain spectroscopy and compared with identical structures produced by conventional photolithography and etching techniques. The broader linewidth of their resonances is shown to originate mainly from structural inhomogeneities. Our study shows that inkjet printing is a viable route for producing metamaterial structures, allowing for rapid processing and flexibility in the choice of substrates.
Tactile objects based on an amplitude disturbed diffraction pattern method
Authors: Liu Yuan , Nikolovski Jean-Pierre , Mechbal Nazih , Hafez Moustapha , Vergé Michel
Published: December 2009

Tactile sensing is becoming widely used in human-computer interfaces. Recent advances in acoustic approaches demonstrated the possibilities to transform ordinary solid objects into interactive interfaces. This letter proposes a static finger contact localization process using an amplitude disturbed diffraction pattern method. The localization method is based on the following physical phenomenon: a finger contact modifies the energy distribution of acoustic wave in a solid; these variations depend on the wave frequency and the contact position. The presented method first consists of exciting the object with an acoustic signal with plural frequency components. In a second step, a measured acoustic signal is compared with prerecorded values to deduce the contact position. This position is then used for human-machine interaction (e.g., finger tracking on computer screen). The selection of excitation signals is discussed and a frequency choice criterion based on contrast value is proposed. Tests on a sandwich plate (liquid crystal display screen) prove the simplicity and easiness to apply the process in various solids.
High-resolution transparent carbon electrodes for organic field-effect transistors patterned by laser sintering
Authors: Wada Hiroshi , Mori Takehiko
Published: December 2009

Organic transistors are fabricated by selective laser sintering of carbon films formed from carbon solution. This method achieves low-cost and high-resolution carbon electrodes with the channel length down to 2 μm without using vacuum process and lithography. The resulting bottom-contact pentacene transistor realizes high performance owing to the low carbon/organic interfacial potential. Since the carbon film is as thin as 60 nm, the film is practically transparent.
Strain hardening in bidisperse polymer glasses: Separating the roles of chain orientation and interchain entanglement
Authors: Hoy Robert S. , Robbins Mark O.
Published: December 2009

The effects of entanglement and chain orientation on strain hardening in glassy polymers are separated by examining mixtures of chains with different lengths. Simulations show that the orientation of a molecule of a given chain length is the same in monodisperse systems and bidisperse mixtures, even when entangled and unentangled chains are mixed. In addition, the stress in mixtures is equal to the weighted average of the stresses in monodisperse systems. These results indicate that chains contribute independently to strain hardening, that chain orientation is determined by local interactions with the surrounding glass, and that entanglements play at most an indirect role in strain hardening in the range of strains typically studied. We discuss these results in the context of recent theories.
Antiferromagnetic spin ordering in the dissociative adsorption of H2 on Si(001): Density-functional calculations
Authors: Choi Jin-Ho , Kim Kwang S. , Cho Jun-Hyung
Published: December 2009

The dissociative adsorption of an H2 molecule on the Si(001) surface, which has been experimentally identified in terms of dissociation on one side of two adjacent Si dimers, is investigated by spin polarized density-functional calculations within the generalized-gradient approximation. In contrast to the prevailing nonmagnetic configuration of charge ordering, we propose a new ground state where the two single dangling bonds (DBs) created by H2 dissociation are antiferromagnetically coupled with each other. Such a spin ordering is found to be energetically favored over the previously proposed charge ordering. In the latter configuration, the buckling of the two DBs amounts to a height difference (Δh) of 0.63 Å, caused by a Jahn–Teller-like distortion, while in the former configuration, their buckling is almost suppressed to be Δh=0.03 Å as a consequence of spin polarization.
Electrically reconfigurable optical metamaterial based on colloidal dispersion of metal nanorods in dielectric fluid
Authors: Golovin Andrii B. , Lavrentovich Oleg D.
Published: December 2009

Optical metamaterials capture the imagination with breathtaking promises of nanoscale resolution in imaging and invisibility cloaking. We demonstrate an approach to construct a metamaterial in which metallic nanorods, of dimension much smaller than the wavelength of light, are suspended in a fluid and placed in a nonuniform electric field. The field controls the spatial distribution and orientation of nanorods because of the dielectrophoretic effect. The field-controlled placement of nanorods causes optical effects such as varying refractive index, optical anisotropy (birefringence), and reduced visibility of an object enclosed by the metamaterial.
Defining the role of syndecan-4 in mechanotransduction using surface-modification approaches
Authors: Bellin Robert M. , Kubicek James D. , Frigault Matthew J. , Kamien Andrew J. , Steward Robert L. , Barnes Hillary M. , DiGiacomo Michael B. , Duncan Luke J. , Edgerly Christina K. , Morse Elizabeth M. , Park Chan Young , Fredberg Jeffrey J. , Cheng Chao-Min , LeDuc Philip R.
Published: December 2009

The ability of cells to respond to external mechanical stimulation is a complex and robust process involving a diversity of molecular interactions. Although mechanotransduction has been heavily studied, many questions remain regarding the link between physical stimulation and biochemical response. Of significant interest has been the contribution of the transmembrane proteins involved, and integrins in particular, because of their connectivity to both the extracellular matrix and the cytoskeleton. Here, we demonstrate the existence of a mechanically based initiation molecule, syndecan-4. We first demonstrate the ability of syndecan-4 molecules to support cell attachment and spreading without the direct extracellular binding of integrins. We also examine the distribution of focal adhesion-associated proteins through controlling surface interactions of beads with molecular specificity in binding to living cells. Furthermore, after adhering cells to elastomeric membranes via syndecan-4-specific attachments we mechanically strained the cells via our mechanical stimulation and polymer surface chemical modification approach. We found ERK phosphorylation similar to that shown for mechanotransductive response for integrin-based cell attachments through our elastomeric membrane-based approach and optical magnetic twisting cytometry for syndecan-4. Finally, through the use of cytoskeletal disruption agents, this mechanical signaling was shown to be actin cytoskeleton dependent. We believe that these results will be of interest to a wide range of fields, including mechanotransduction, syndecan biology, and cell–material interactions.
Influence of environmental statistics on inhibition of saccadic return
Authors: Farrell Simon , Ludwig Casimir J. H. , Ellis Lucy A. , Gilchrist Iain D.
Published: December 2009

Initiating an eye movement is slowed if the saccade is directed to a location that has been fixated in the recent past. We show that this inhibitory effect is modulated by the temporal statistics of the environment: If a return location is likely to become behaviorally relevant, inhibition of return is absent. By fitting an accumulator model of saccadic decision-making, we show that the inhibitory effect and the sensitivity to local statistics can be dissociated in their effects on the rate of accumulation of evidence, and the threshold controlling the amount of evidence needed to generate a saccade.
Ablation of SLP-76 signaling after T cell priming generates memory CD4 T cells impaired in steady-state and cytokine-driven homeostasis
Authors: Bushar Nicholas D. , Corbo Evann , Schmidt Michelle , Maltzman Jonathan S. , Farber Donna L.
Published: December 2009

The intracellular signaling mechanisms regulating the generation and long-term persistence of memory T cells in vivo remain unclear. In this study, we used mouse models with conditional deletion of the key T cell receptor (TCR)-coupled adaptor molecule SH2-domain-containing phosphoprotein of 76 kDa (SLP-76), to analyze signaling mechanisms for memory CD4 T cell generation, maintenance, and homeostasis. We found that ablation of SLP-76 expression after T cell priming did not inhibit generation of phenotypic effector or memory CD4 T cells; however, the resultant SLP-76–deficient memory CD4 T cells could not produce recall cytokines in response to TCR-mediated stimulation and showed decreased persistence in vivo. In addition, SLP-76–deficient memory CD4 T cells exhibited reduced steady-state homeostasis and were impaired in their ability to homeostatically expand in vivo in response to the γ
c
cytokine IL-7, despite intact proximal signaling through the IL-7R–coupled JAK3/STAT5 pathway. Direct in vivo deletion of SLP-76 in polyclonal memory CD4 T cells likewise led to impaired steady-state homeostasis as well as impaired homeostatic responses to IL-7. Our findings demonstrate a dominant role for SLP-76–dependent TCR signals in regulating turnover and perpetuation of memory CD4 T cells and their responses to homeostatic cytokines, with implications for the selective survival of memory CD4 T cells following pathogen exposure, vaccination, and aging.
Saccharomyces cerevisiae
Msh2-Msh6 DNA binding kinetics reveal a mechanism of targeting sites for DNA mismatch repair
Authors: Zhai Jie , Hingorani Manju M.
Published: December 2009

The DNA mismatch repair system (MMR) identifies replication errors and damaged bases in DNA and functions to preserve genomic integrity. MutS performs the task of locating mismatched base pairs, loops and lesions and initiating MMR, and the fundamental question of how this protein targets specific sites in DNA is unresolved. To address this question, we examined the interactions between
Saccharomyces cerevisiae
Msh2-Msh6, a eukaryotic MutS homolog, and DNA in real time. The reaction kinetics reveal that Msh2-Msh6 binds a variety of sites at similarly fast rates (
k
ON
 ∼ 10
7
 M
-1
 s
-1
), and its selectivity manifests in differential dissociation rates; e.g., the protein releases a 2-Aminopurine:T base pair approximately 90-fold faster than a G:T mismatch. On releasing the 2-Ap:T site, Msh2-Msh6 is able to move laterally on DNA to locate a nearby G:T site. The long-lived Msh2-Msh6·G:T complex triggers the next step in MMR—formation of an ATP-bound clamp—more effectively than the short-lived Msh2-Msh6·2-Ap:T complex. Mutation of Glu in the conserved Phe-X-Glu DNA binding motif stabilizes Msh2-Msh6
E339A
·2-Ap:T complex, and the mutant can signal 2-Ap:T repair as effectively as wild-type Msh2-Msh6 signals G:T repair. These findings suggest a targeting mechanism whereby Msh2-Msh6 scans DNA, interrogating base pairs by transient contacts and pausing at potential target sites, and the longer the pause the greater the likelihood of MMR.
Actin polymerization driven mitochondrial transport in mating
S. cerevisiae
Authors: Senning Eric N. , Marcus Andrew H.
Published: December 2009

The dynamic microenvironment of cells depends on macromolecular architecture, equilibrium fluctuations, and nonequilibrium forces generated by cytoskeletal proteins. We studied the influence of these factors on the motions of mitochondria in mating
S. cerevisiae
using Fourier imaging correlation spectroscopy (FICS). Our measurements provide detailed length-scale dependent information about the dynamic behavior of mitochondria. We investigate the influence of the actin cytoskeleton on mitochondrial motion and make comparisons between conditions in which actin network assembly and disassembly is varied either by using disruptive pharmacological agents or mutations that alter the rates of actin polymerization. Under physiological conditions, nonequilibrium dynamics of the actin cytoskeleton leads to 1.5-fold enhancement of the long-time mitochondrial diffusion coefficient and a transient subdiffusive temporal scaling of the mean-square displacement (MSD ∝ 
τ

α

, with
α
 = 2/3). We find that nonequilibrium forces associated with actin polymerization are a predominant factor in driving mitochondrial transport. Moreover, our results lend support to an existing model in which these forces are directly coupled to mitochondrial membrane surfaces.
R loops stimulate genetic instability of CTG·CAG repeats
Authors: Lin Yunfu , Dent Sharon Y. R. , Wilson John H. , Wells Robert D. , Napierala Marek
Published: December 2009

Transcription stimulates the genetic instability of trinucleotide repeat sequences. However, the mechanisms leading to transcription-dependent repeat length variation are unclear. We demonstrate, using biochemical and genetic approaches, that the formation of stable RNA·DNA hybrids enhances the instability of CTG·CAG repeat tracts. In vitro transcribed CG-rich repeating sequences, unlike AT-rich repeats and nonrepeating sequences, form stable, ribonuclease A-resistant structures. These RNA·DNA hybrids are eliminated by ribonuclease H treatment. Mutation in thernhA1gene that decreases the activity of ribonuclease HI stimulates the instability of CTG·CAG repeats inE. coli. Importantly, the effect of ribonuclease HI depletion on repeat instability requires active transcription. We also showed that transcription-dependent CTG·CAG repeat instability in human cells is stimulated by siRNA knockdown of RNase H1 and H2. In addition, we used bisulfite modification, which detects single-stranded DNA, to demonstrate that the nontemplate DNA strand at transcribed CTG·CAG repeats remains partially single-stranded in human genomic DNA, thus indicating that it is displaced by an RNA·DNA hybrid. These studies demonstrate that persistent hybrids between the nascent RNA transcript and the template DNA strand at CTG·CAG tracts promote instability of DNA trinucleotide repeats.
Distinct nonuniform cable properties optimize rapid and efficient activation of fast-spiking GABAergic interneurons
Authors: Nörenberg Anja , Hu Hua , Vida Imre , Bartos Marlene , Jonas Peter
Published: December 2009

Fast-spiking, parvalbumin-expressing basket cells (BCs) play a key role in feedforward and feedback inhibition in the hippocampus. However, the dendritic mechanisms underlying rapid interneuron recruitment have remained unclear. To quantitatively address this question, we developed detailed passive cable models of BCs in the dentate gyrus based on dual somatic or somatodendritic recordings and complete morphologic reconstructions. Both specific membrane capacitance and axial resistivity were comparable to those of pyramidal neurons, but the average somatodendritic specific membrane resistance (R
m
) was substantially lower in BCs. Furthermore, R
m
was markedly nonuniform, being lowest in soma and proximal dendrites, intermediate in distal dendrites, and highest in the axon. Thus, the somatodendritic gradient of R
m
was the reverse of that in pyramidal neurons. Further computational analysis revealed that these unique cable properties accelerate the time course of synaptic potentials at the soma in response to fast inputs, while boosting the efficacy of slow distal inputs. These properties will facilitate both rapid phasic and efficient tonic activation of BCs in hippocampal microcircuits.