bluuebunny/crossref_metadata_2025 huggingface dataset:
Delayed synapse elimination in mouse levator palpebrae superioris muscle
Authors: Fox Michael A. , Tapia Juan Carlos , Kasthuri Narayanan , Lichtman Jeff W.
Published: August 2011

At birth, synaptic sites in developing rodent muscles are innervated by numerous motor axons. During subsequent weeks, this multiple innervation disappears as one terminal strengthens, and all the others are eliminated. Experimental perturbations that alter neuromuscular activity affect the rate of synaptic refinement, with more activity accelerating the time to single innervation and neuromuscular blockade retarding it. However, it remains unclear whether patterns of muscle use (driven by endogenous neuronal activity) contribute to the rate of synapse elimination. For this reason we examined the timing of supernumerary nerve terminal elimination at synapses in extraocular muscles (EOMs), a specialized set of muscles controlling eye movements. On the basis of their exceptionally high patterns of activity, we hypothesized that synaptic refinement would be greatly accelerated at these synapses. We found, however, that rates of synaptic refinement were only modestly accelerated in rectus and oblique EOMs compared with synapses in somite‐derived skeletal muscle. In contrast to these results, we observed a dramatic delay in the elimination of supernumerary nerve terminals from synapses in the levator palpebrae superioris (LPS) muscle, a specialized EOM that initiates and maintains eyelid elevation. In mice, natural eye opening occurs at the end of the second postnatal week of development. Thus, although synapse elimination is occurring in most EOMs and somite‐derived skeletal muscles, it appears to be dramatically delayed in a set of specialized eyelid muscles that remain immobile during early postnatal development. J. Comp. Neurol. 519:2907‐2921, 2011. � 2011 Wiley‐Liss, Inc.
Ethanol Dehydration to Ethylene in a Stratified Autothermal Millisecond Reactor
Authors: Skinner Michael J. , Michor Edward L. , Fan Wei , Tsapatsis Michael , Bhan Aditya , Schmidt Lanny D.
Published: August 2011

The concurrent decomposition and deoxygenation of ethanol was accomplished in a stratified reactor with 50–80 ms contact times. The stratified reactor comprised an upstream oxidation zone that contained Pt‐coated Al2O3 beads and a downstream dehydration zone consisting of H‐ZSM‐5 zeolite films deposited on Al2O3 monoliths. Ethanol conversion, product selectivity, and reactor temperature profiles were measured for a range of fuel:oxygen ratios for two autothermal reactor configurations using two different sacrificial fuel mixtures: a parallel hydrogen–ethanol feed system and a series methane–ethanol feed system. Increasing the amount of oxygen relative to the fuel resulted in a monotonic increase in ethanol conversion in both reaction zones. The majority of the converted carbon was in the form of ethylene, where the ethanol carboncarbon bonds stayed intact while the oxygen was removed. Over 90 % yield of ethylene was achieved by using methane as a sacrificial fuel. These results demonstrate that noble metals can be successfully paired with zeolites to create a stratified autothermal reactor capable of removing oxygen from biomass model compounds in a compact, continuous flow system that can be configured to have multiple feed inputs, depending on process restrictions.
Glia unglued: How signals from the extracellular matrix regulate the development of myelinating glia
Authors: Colognato Holly , Tzvetanova Iva D.
Published: August 2011

The health and function of the nervous system relies on glial cells that ensheath neuronal axons with a specialized plasma membrane termed myelin. The molecular mechanisms by which glial cells target and enwrap axons with myelin are only beginning to be elucidated, yet several studies have implicated extracellular matrix proteins and their receptors as being important extrinsic regulators. This review provides an overview of the extracellular matrix proteins and their receptors that regulate multiple steps in the cellular development of Schwann cells and oligodendrocytes, the myelinating glia of the PNS and CNS, respectively, as well as in the construction and maintenance of the myelin sheath itself. The first part describes the relevant cellular events that are influenced by particular extracellular matrix proteins and receptors, including laminins, collagens, integrins, and dystroglycan. The second part describes the signaling pathways and effector molecules that have been demonstrated to be downstream of Schwann cell and oligodendroglial extracellular matrix receptors, including FAK, small Rho GTPases, ILK, and the PI3K/Akt pathway, and the roles that have been ascribed to these signaling mediators. Throughout, we emphasize the concept of extracellular matrix proteins as environmental sensors that act to integrate, or match, cellular responses, in particular to those downstream of growth factors, to appropriate matrix attachment. © 2011 Wiley Periodicals, Inc. Develop Neurobiol 71: 924‐955, 2011
Induced Syk deletion leads to suppressed allergic responses but has no effect on neutrophil or monocyte migration in vivo
Authors: Wex Eva , Bouyssou Thierry , Duechs Matthias J. , Erb Klaus J. , Gantner Florian , Sanderson Michael P. , Schnapp Andreas , Stierstorfer Birgit E. , Wollin Lutz
Published: August 2011

The spleen tyrosine kinase (Syk) is a key mediator of immunoreceptor signaling in immune cells. Thus, interfering with the function of Syk by genetic deletion or pharmacological inhibition might influence a variety of allergic and autoimmune processes. Since conventional Syk knockout mice are not viable, studies addressing the effect of Syk deletion in adult animals have been limited. To further explore functions of Syk in animal models of allergy and to shed light on the role of Syk in the in vivo migration of neutrophils and monocytes, we generated inducible Syk knockout mice. These mice harbor a floxed Syk gene and a tamoxifen‐inducible Cre recombinase under the control of the ubiquitously active Rosa26‐promoter. Thus, treatment of mice with tamoxifen leads to the deletion of Syk in all organs. Syk‐deleted mice were analyzed in mast cell‐dependent models and in models focusing on neutrophil and monocyte migration. We show that Syk deletion in adult mice reduces inflammatory responses in mast cell‐driven animal models of allergy and asthma but has no effect on the migration of neutrophils and monocytes. Therefore, the inducible Syk knockout mice presented here provide a valuable tool to further explore the role of Syk in disease‐related animal models.
Nickel(II) Coordination Polymers – 4,4′‐Bipyridine‐Connected Six‐ and Four‐Fold Metal–Succinate Helices and Their Corresponding Chiral and Achiral Networks
Authors: Das Sunirban , Maloth Swamy , Pal Samudranil
Published: August 2011

The reaction of equimolar amounts of Ni(NO3)2·6H2O, Na2(suc)·6H2O (suc = succinate) and 4,4′‐bipyridine (bipy) under different conditions yield the coordination polymers [Ni(suc)(bipy)(H2O)2]n·2nH2O (1) and [Ni(suc)(bipy)(H2O)2]n·nH2O (2). The complexes were characterized by elemental analysis, spectroscopic, thermogravimetric, and magnetic susceptibility measurements. Crystal structures reveal that the metal centers in both complexes are in a distorted octahedral N2O4 coordination sphere assembled by mutually trans pairs of 4,4′‐bipyridine, succinate, and water molecules. The helical metal–succinate chains have a right‐handed sixfold configuration in 1, with guest water molecules inside the helix, and both right‐ and left‐handed fourfold configurations in 2, with guest water molecules outside the helix. The parallel helical substructures are connected by 4,4′‐bipyridine and provide 3D chiral 75.9 and achiral 65.8 networks in 1 and 2, respectively.
Simultaneous thin section and phytolith observations of finely stratified deposits from Neolithic Çatalhöyük, Turkey: implications for paleoeconomy and Early Holocene paleoenvironment
Authors: Shillito Lisa‐Marie
Published: August 2011

Simultaneous thin section and phytolith observations of finely stratified anthropogenic deposits from the Neolithic settlement of Çatalhöyük, Turkey, dated between 7400 and 6000 BC provide evidence for both the depositional context and phytolith assemblage of these deposits. Although extracted phytoliths provide a general picture of vegetation that supports existing evidence of a local wet marshland environment, comparisons with observations of phytoliths in situ indicate a diverse range of microcontexts, as well as depositional and post‐depositional processes that influence phytolith size. This has implications for studies that use conjoined phytolith size as a proxy for water availability and early agricultural practices. Observations indicate a significant background noise of phytoliths and micro‐charcoal in the deposits, linked to the frequent use of fire, which has implications for interpreting assemblages where phytolith counts are low, such as from floors of buildings. This study confirms the usefulness of phytoliths in providing information on human plant use and environment where the taphonomy of the deposits is clear, and provides new evidence for wet farming of at least some of the wheat found at the site. It also suggests there needs to be greater consideration of phytolith taphonomy, which can be provided to an extent by combining phytolith analysis with thin section micromorphology. Copyright © 2011 John Wiley & Sons, Ltd.
Late glacial and holocene 10Be production rates for western Norway
Authors: Goehring Brent M. , Lohne Øystein Strand , Mangerud Jan , Svendsen John Inge , Gyllencreutz Richard , Schaefer Joerg , Finkel Robert
Published: August 2011

We present a new regional calibration of the 10Be production rate from two well‐dated surfaces in southern Norway: a rock avalanche with 14C‐dated wood and a precisely dated Younger Dryas moraine. Calculated 10Be production rates are 4.26 ± 0.13 and 4.65 ± 0.14 at g−1 a−1 for the Lal/Stone and Lifton scaling models, respectively. Our regional production rate for southern Norway is 5% lower than the canonical global 10Be production rate with lower uncertainties. Our 10Be production rate agrees with regional 10Be production rates from north‐eastern North America and New Zealand. The 10Be production rate estimate presented here can be used to improve the precision and accuracy of exposure‐dated ice‐marginal features, as well as other surfaces, in northern Europe. Copyright © 2011 John Wiley & Sons, Ltd.
Role of risk factors proximate to time of trauma in the course of PTSD and MDD symptoms following traumatic injury
Authors: Norman Sonya B. , Trim Ryan S. , Goldsmith Abigail A. , Dimsdale Joel E. , Hoyt David B. , Norman Gregory J. , Stein Murray B.
Published: August 2011

Questions exist regarding whether posttraumatic stress disorder (PTSD) and major depressive disorder (MDD) are unique sequelae of trauma or a manifestation of a single form of psychopathology. Using latent growth modeling, we examined the role of risk factors occurring within 48 hours of the time of trauma on the course of PTSD and MDD symptoms over an 8‐month period in 163 participants recruited from a level 1 surgical trauma center. Both PTSD and MDD symptoms showed peak prevalence by 1 month and significantly decreased over 7 months. Greater postinjury pain and PTSD symptoms (measured within 48 hours of trauma) predicted higher rates of both PTSD and MDD symptoms at 1 month. Other predictors were unique to each disorder. Results suggest that PTSD and MDD are related consequences of trauma.
Differential risk of Clostridium difficile infection with proton pump inhibitor use by level of antibiotic exposure
Authors: Stevens Vanessa , Dumyati Ghinwa , Brown Jack , van Wijngaarden Edwin
Published: August 2011

Purpose

Clostridium difficile infection (CDI) is a major cause of hospital‐acquired diarrhea worldwide. We examined the risk of CDI associated with the use of acid‐suppressive agents (proton pump inhibitors [PPI] and histamine‐2 receptor blockers) and determined whether this risk varied by number or type of antibiotic (high or low CDI risk) received during hospitalization.

Methods

We conducted a retrospective cohort study of hospitalizations among adult patients at an academic teaching hospital in Rochester, New York, during which two or more days of antibiotics were prescribed. Multivariable marginal Cox proportional hazards models with time‐varying exposures were used to examine time to the development of CDI.

Results

A total of 10 154 hospitalizations and 241 cases of CDI, defined as detection of C. difficile toxin in a diarrheal stool sample within 60 days of discharge, were identified. PPI use was independently associated with an increased risk of CDI (adjusted hazard ratio = 4.5; 95% confidence interval [CI] = 2.3–9.0). Among hospitalizations during which one, two, three or four, and five or more antibiotics were prescribed, the adjusted hazard ratios for PPI use were 15.7 (CI = 6.4–38.8), 4.9 (CI = 2.2–11.2), 4.3 (CI = 1.9–9.9), and 2.7 (CI = 1.2–5.9), respectively (p for interaction = .002).

Conclusions

The use of PPI is common among patients receiving antibiotics during hospitalization. The greater risk of CDI in relation to PPI among hospitalizations during which fewer or low‐risk antibiotics were prescribed suggests a potentially clinically relevant interaction between antibiotics and PPI. Further study is needed to elucidate possible mechanisms for the observed effect. Copyright © 2011 John Wiley & Sons, Ltd.
Validation of a needs‐based biopsychosocial distress instrument for cancer patients
Authors: Lowery Amy E. , Greenberg Melanie A. , Foster Sharon L. , Clark Karen , Casden Danielle R. , Loscalzo Matthew , Bardwell Wayne A.
Published: August 2011

Objective

People with cancer may experience distress related to diagnoses, disease‐related symptoms, and treatment side effects. Assessment of cancer‐related needs can facilitate timely triage and intervention and contribute to individualized comprehensive cancer care. This study assessed the internal consistency, test–retest reliability and construct validity of the Cancer Needs Distress Inventory (CaNDI), a self‐report, needs‐based measure of cancer‐related distress.

Methods

A sample of 100 patients (27% male) with various cancer diagnoses completed the CaNDI, Hospital Anxiety and Depression Scale, Brief Symptom Inventory, Functional Assessment of Cancer Therapy‐General, and the Paulhus Deception Scales.

Results

The CaNDI total and depressive and anxiety subscale scores all demonstrated excellent test–retest reliability and moderate to high correlations with other measures of these constructs. The instrument was minimally confounded by social desirability and provided high sensitivity and specificity in detecting depression and anxiety.

Conclusions

Initial results suggest that the CaNDI has strong psychometric properties and may be a useful addition to cancer patient needs assessment, research and care. Copyright © 2011 John Wiley & Sons, Ltd.
Morphology control of a rapidly grown vertically aligned carbon‐nanotube forest for fiber spinning
Authors: Iijima T. , Oshima H. , Hayashi Y. , Suryavanshi U. B. , Hayashi A. , Tanemura M.
Published: August 2011

Carbon nanotube (CNT) fibers have interesting applications because of their good electrical and mechanical properties. CNT fiber is fabricated in a simple way, that it is spun from a vertically aligned CNT forest (VACNF). Spinning occurs by joining of CNT when the CNT at the edge of a VACNF is drawn horizontally. However, the mechanism of spinning is still not clear. To investigate it, we fabricated a spinnable VACNF by thermal chemical vapor deposition (CVD) and compared it with unspinnable VACNF by scanning electron microscope (SEM) observation and polarized Raman spectroscopy. It was found that there were a few big differences between spinnable and unspinnable VACNFs. In the case of spinnable VACNF, most of the CNTs are straight and well aligned. Spinnable VACNF also contains CNT bundles consisting of 8–10 CNTs that are not vertically aligned. This CNT bundle was shared by a few adjacent thicker CNT bundles. These points are very important for continuous fiber spinning.
Interface electrical properties of Fe3O4/MgO/GaAs(100) epitaxial spin contacts
Authors: Wong Ping Kwan Johnny , Zhang Wen , Xu Yongbing
Published: August 2011

We have successfully accomplished the growth and fabrication of two types of molecular‐beam epitaxy‐grown Fe3O4‐based spin contacts on GaAs(100): (i) Fe3O4/GaAs direct contact, and (ii) Fe3O4/MgO/GaAs tunnel junction, both of which can be potentially used for electrical spin injection and detection at room temperature. Using current–voltage (I–V) measurements, we show, for the first time, the very different interface electrical properties of those epitaxial spin contacts on GaAs(100) surfaces. A more symmetric I–V relationship has been revealed in Fe3O4/MgO/GaAs(100) tunnel junctions, meaning that thermionic emission, which is important in epitaxial Fe3O4/GaAs(100) no longer plays a dominant role and that electron tunneling across the MgO tunnel barrier takes over the electronic transport characteristics. Moreover, by manipulating the MgO layer thickness (0.5 to 3.0 nm), the contact resistance of the tunnel junctions, a prerequisite parameter determining the efficiency of spin injection and detection into GaAs, can be tuned over three orders of magnitude.
Nanomanipulation of 2 inch wafer fabrication of vertically aligned carbon nanotube arrays by nanoimprint lithography
Authors: Bu Ian Y. Y. , Eichhorn Volkmar , Carlson Kenneth , Boggild Peter , Fatikow Sergej
Published: August 2011

Carbon nanotube (CNT) arrays are typically defined by electron beam lithography (EBL), and hence limited to small areas due to the low throughput. To obtain wafer‐scale fabrication we propose large area thermal nanoimprint lithography (NIL). A 2‐inch stamp master is defined using EBL for subsequent pattern transfer to a hard metal mask before deep reactive ion etching (RIE) to form the stamp protrusions. This stamp master is then pressed against a wafer covered with nanoimprint resist, at a temperature above the glass transition temperature, transferring the pattern to polymer. Using this process, efficient production of wafer‐scale/larger arrays of CNTs has been achieved. The CNTs have been deposited by wafer‐scale plasma enhanced chemical vapour deposition (PECVD) of C2H2/NH3. Substrates containing such nanotubes have been used to automate nanorobotic manipulation sequences of individual CNTs and their assembly into prototypic CNT‐based devices.
Monte Carlo simulation on magnetic properties in triangular Heisenberg system with single‐ion anisotropy
Authors: Yao Xiaoyan
Published: August 2011

The magnetic properties dependent on temperature and external magnetic field in the spin frustrated triangular system are investigated by using Monte Carlo (MC) simulation on a Heisenberg spin model. The single‐ion anisotropy with different magnitudes is introduced to scrutinize the variation of magnetic behavior. It is revealed that the strong anisotropy is an essential key to induce the step‐like magnetization as a function of magnetic field, as observed in the triangular spin‐chain compound Ca3Co2O6 at low temperature. Furthermore, the critical temperature, at which the stepwise magnetic behavior emerges is raised by increasing the anisotropy. This is attributed to the collinear spin structure strengthened by the anisotropy.
Magnetic properties of Cr‐doped ZnO nanorods fabricated by hydrothermal method in a high pulsed magnetic field
Authors: Zhu Mingyuan , Hu Yemin , Li Ying , Li Yibing , Jin Hongming
Published: August 2011

Cr‐doped ZnO diluted magnetic semiconductor (DMS) nanorods with nominal composition of 1 at.% were synthesized by a hydrothermal method with the assistance of a high pulsed magnetic field (HHPMF). All the Cr‐doped ZnO samples obtained with or without the applied high magnetic field exhibited room‐temperature ferromagnetic behavior. It is observed that the high magnetic field plays an important role in saturation magnetization of the samples. The effects of high magnetic field on the morphology, structure, and magnetic properties of the samples were discussed.
Spontaneous formation and characterization of silicon carbide nanowires produced via thermolysis
Authors: Soszyński Michał , Dąbrowska Agnieszka , Huczko Andrzej
Published: August 2011

We report on experiments to optimize the process of preparation of silicon carbide nanowires (SiCNWs) by a combustion synthesis (thermolysis). The morphology of starting reactants and combustion atmosphere were varied and we observed the effect of those variables on product yield and characteristics. The produced SiCNWs were characterized using SEM, TEM, XRD, and wet chemistry analysis.

magnified image

High‐pressure reactor used for combustion synthesis, combustion reaction, and TEM of produced SiCNW
Monitoring the Weibull Shape Parameter by Control Charts for the Sample Range of Type II Censored Data
Authors: Pascual Francis , Li Shuo
Published: August 2011

In this paper, we propose control charts to monitor the Weibull shape parameter β under type II (failure) censoring. This chart scheme is based on the sample ranges of smallest extreme value distributions derived from Weibull processes. We suggest one‐sided (high‐side or low‐side) and two‐sided charts, which are unbiased with respect to the average run length (ARL). The control limits for all types of charts depend on the sample size, the number of failures c under type II censoring, the desired stable‐process ARL, and the stable‐process value of β. This article also considers sample size requirements for phase I in retrospective charts. We investigate the effect of c on the out‐of‐control ARL. We discuss a simple approach to choosing c by cost minimization. The proposed schemes are then applied to data on the breaking strengths of carbon fibers. Copyright © 2011 John Wiley & Sons, Ltd.
Robust real‐time robot–world calibration for robotized transcranial magnetic stimulation
Authors: Richter Lars , Ernst Floris , Schlaefer Alexander , Schweikard Achim
Published: August 2011

Background

For robotized transcranial magnetic stimulation (TMS), the magnetic coil is placed on the patient's head by a robot. As the robotized TMS system requires tracking of head movements, robot and tracking camera need to be calibrated. However, for robotized TMS in a clinical setting, such calibration is required frequently. Mounting/unmounting a marker to the end effector and moving the robot into different poses is impractical. Moreover, if either system is moved during treatment, recalibration is required.

Methods

To overcome this limitation, we propose to directly track a marker at link three of the articulated arm. Using forward kinematics and a constant marker transform to link three, the calibration can be performed instantly.

Results

Our experimental results indicate an accuracy similar to standard hand‐eye calibration approaches. It also outperforms classical hand‐held navigated TMS systems.

Conclusion

This robust online calibration greatly enhances the system's user‐friendliness and safety. Copyright © 2011 John Wiley & Sons, Ltd.
Adsorption of Metanil Yellow Azoic Dye from Aqueous Solution onto Mg‐Fe‐NO3 Layered Double Hydroxide
Authors: Nejati Kamellia , Rezvani Zolfaghar , Mansurfar Mahsa , Mirzaee Abolfazl , Mahkam Mehrdad
Published: August 2011

We report the preparation and characterization of a layered double hydroxide (LDH) adsorbent for azoic dye, metanil yellow (yellow GX; YGX) removal. The nanoparticles of Mg‐Fe‐LDH‐NO3 adsorbent were prepared with Mg/Fe molar ratio of 3:1 by a hydrothermal process and coprecipitation method at pH 9.5 and were characterized by X‐ray powder diffraction (XRPD), thermal gravimetric analysis (TGA), elemental analysis, and Fourier transform infrared spectroscopy (FT‐IR). The size and morphology of nanoparticles were examined by scanning electron microscopy (SEM). The XRD patterns indicate that the intercalation of YGX between the LDH layers has not occurred and surface adsorption has happened. In the adsorption experiments, the Gibbs free energy ΔG0 values, the enthalpy ΔH0, and entropy ΔS0 was determined. The isotherms showed that the adsorption of YGX by Mg‐Fe‐LDH‐NO3 was both consistent with Langmuir and Freundlich equations.
Sources of Uncertainty About Daughters’ Breast Cancer Risk that Emerge During Genetic Counseling Consultations
Authors: Bylund Carma L. , Fisher Carla L. , Brashers Dale , Edgerson Shawna , Glogowski Emily A. , Boyar Sherry R. , Kemel Yelena , Spencer Sara , Kissane David
Published: August 2011

Uncertainty is central to the experience of genetic decision making and counseling about cancer risk. Women seeking genetic counseling about their breast cancer risk may experience a great deal of uncertainty about issues related to their daughters. We used a theory of Communication and Uncertainty Management to guide analysis of sources of uncertainty about daughters that emerged during 16 video‐recorded and transcribed conversations between mothers at risk for a BRCA 1/2 mutation and their genetic healthcare practitioners. An interpretive design and constant comparative method revealed three dominant patterns or themes representing sources of uncertainty mothers have relating to their daughters: disease risk, future cancer screening, and communication of related information to daughters. Both practitioners and mothers discussed these aspects of uncertainty. The findings identify the significant role uncertainty and familial concerns play in mothers’ genetic testing decision making process. To assist genetic practitioners, we highlight daughter‐related concerns that mothers are uncertain about and which are vital to their genetic counseling needs.
Nonequilibrium capillarity effects in two‐phase flow through porous media at different scales
Authors: Bottero S. , Hassanizadeh S. M. , Kleingeld P. J. , Heimovaara T. J.
Published: August 2011

A series of primary drainage experiments was carried out in order to investigate nonequilibrium capillarity effects in two‐phase flow through porous media. Experiments were performed with tetrachloroethylene (PCE) and water as immiscible fluids in a sand column 21 cm long. Four drainage experiments were performed by applying large pressures on the nonwetting phase at the inlet boundary: 20, 30, 35, 38 kPa. Our results showed that the nonequilibrium local fluids pressure difference‐saturation curves are above the capillary pressure saturation curve. Moreover, the nonequilibrium pressure difference showed a nonmonotonic behavior with an overshoot that was more pronounced at higher injection pressures. The dynamic capillarity coefficient was calculated from measured local pressures and saturations (the scale of sensor devices, 0.7 cm). Its value was found to vary between 1.3 × 105 to 2 × 105 Pa s. Within the saturation range of 0.50 > Sw > 0.85, no clear dependency of the dynamic coefficient on the wetting saturation was observed. Also, no dependency of the dynamic capillarity coefficient on the applied boundary pressure was found. Averaged values of at the length scales of 11 and 18 cm were also estimated from averaged pressures and saturations. The upscaled dynamic coefficient was found to vary between 0.5 × 106 and 1.2 × 106 Pa s at the average window size of 11 cm. This is one order of magnitude larger than the local‐scale coefficient. Larger values were found for the length scale of 18 cm: 1.5 × 106 and 2.5 × 106 Pa s. This suggests that the value of dynamic coefficient increases with the scale of observation.
Acetylsalicylic Acid, but Not Clopidogrel, Inhibits Therapeutically Induced Cerebral Arteriogenesis in the Hypoperfused Rat Brain
Authors: Duelsner André , Gatzke Nora , Glaser Johanna , Hillmeister Philipp , Li Meijing , Lee Eun-Ji , Lehmann Kerstin , Urban Daniel , Meyborg Heike , Stawowy Philipp , Busjahn Andreas , Nagorka Stephanie , Persson Anja Bondke , Buschmann Ivo R
Published: August 2011

This study investigated the effects of acetylsalicylic acid (ASA) and clopidogrel, standardly used in the secondary prevention of vascular occlusions, on cerebral arteriogenesis in vivo and in vitro. Cerebral hypoperfusion was induced by three-vessel occlusion (3-VO) in rats, which subsequently received vehicle, ASA (6.34 mg/kg), or clopidogrel (10 mg/kg). Granulocyte colony-stimulating factor (G-CSF), which enhanced monocyte migration in an additional cell culture model, augmented cerebrovascular arteriogenesis in subgroups (40 μg/kg). Cerebrovascular reactivity and vessel diameters were assessed at 7 and 21 days. Cerebrovascular reserve capacity was completely abolished after 3-VO and remained severely compromised after 7 (−14 ± 14%) and 21 (−5 ± 11%) days in the ASA groups in comparison with controls (4 ± 5% and 10 ± 10%) and clopidogrel (4 ± 13% and 10 ± 8%). It was still significantly decreased when ASA was combined with G-CSF (1 ± 4%) compared with G-CSF alone (20 ±8%). Posterior cerebral artery diameters confirmed these data. Monocyte migration into the vessel wall, improved by G-CSF, was significantly reduced by ASA. Acetylsalicylic acid, but not clopidogrel, inhibits therapeutically augmented cerebral arteriogenesis.
Decommissioning of Nuclear Sites
Authors: Banford Anthony W. , Jarvis Richard B.
Published: August 2011

This paper discusses the various phases of decommissioning and what they seek to achieve, and discusses some drivers for decommissioning both immediately after operations cease and after a period of time. The scale of the decommissioning challenge in the UK is then outlined and some criteria for the selection of the best decommissioning option for a facility are introduced. Finally, the potential environmental impacts of each of the different decommissioning stages are discussed.
Radiation Protection of the Environment: A Summary of Current Approaches for Assessment of Radionuclides in Terrestrial Ecosystems
Authors: Howard B. J. , Beresford N. A.
Published: August 2011

Over the past decade the international community has recognised the need to demonstrate that wildlife populations are protected from environmental releases of radioactivity as well as humans. Frameworks and models for such assessments have been developed and are continuously being tested and improved. In this chapter, the basic elements of an assessment for radiation exposure of wildlife are outlined, including the current methods used to estimate environmental radionuclide transfer and the resulting doses. The methods used to derive benchmarks based on radiation effects data, against which estimated doses can be compared, are described. Since it is impossible to quantify transfer and doses for all species, the approaches use representative groups such as “reference organisms” including the Reference Animals and Plants of the International Commission on Radiological Protection (ICRP). The current approaches used for wildlife have some commonalities with those used for humans, but with some notable differences. Organisms tend to be considered as homogenous, simplified geometric shapes with the whole organism absorbed dose rate being estimated; the majority of available effects data are expressed on the basis of whole organism dose rates. Transfer is often quantified by predicting the whole organism activity concentration from that in the environmental media such as soil, water or air. Protection is focused on populations rather than individuals, and therefore some approaches used for the assessment of chemicals pollutants are also being adopted for radionuclides.
Boron-deuterium complexes in diamond: How inhomogeneity leads to incorrect carrier type identification
Authors: Kumar A. , Pernot J. , Omnès F. , Muret P. , Traoré A. , Magaud L. , Deneuville A. , Habka N. , Barjon J. , Jomard F. , Pinault M. A. , Chevallier J. , Mer-Calfati C. , Arnault J. C. , Bergonzo P.
Published: August 2011

The electrical properties of boron doped diamond layers after deuterium diffusion have been investigated by Hall effect and capacitance voltage measurements. It is found that (i) the deuterated boron doped diamond layers are inhomogeneous after the deuterium diffusion, resulting in conducting and insulating areas; (ii) negative and positive Hall voltages are measured on the same boron doped sample after deuterium diffusion, depending on the contact geometry (negative with van der Pauw and positive with mesa etched Hall bar); and (iii) in the conducting area, the majority of the boron-deuterium complexes are not ionized after the deuterium diffusion. The detailed electrical measurements using mesa-insulating Hall bar structures revealed that the existence of inhomogeneous regions with conducting and insulating areas is the most probable source of wrong n-type conductivity in deuterated boron doped diamond layers of this work. In the light of this result, the possibility of an incorrect assignment of a shallow donor previously reported in deuterated boron doped diamond is discussed. Finally, confirmation is given that the boron deuterium complexes created after the deuterium diffusion are neutral in p-type diamond.
Observation of nonclassical scaling laws in the quality factors of cantilevered carbon nanotube resonators
Authors: Vallabhaneni Ajit K. , Rhoads Jeffrey F. , Murthy Jayathi Y. , Ruan Xiulin
Published: August 2011

This work examines the quality factors (Q factors) of resonance associated with the axial and transverse vibrations of single-wall carbon nanotube (SWCNT) resonators through the use of molecular dynamics (MD) simulation. Specifically, the work investigates the effect of device length, diameter, and chirality, as well as temperature, on the resonant frequency and quality factor of these devices and benchmarks the results of MD simulations against classical theories of energy dissipation. The quality factor (Q) associated with transverse vibration is found to increase with increasing device length (Q ∼ Lθ, where 0.8 < θ < 1.4) and decrease with increasing device diameter (Q ∼ D−μ, where 1.4 < μ < 1.6), while the Q associated with axial vibration is almost independent of length and diameter. We show that to accurately predict temperature dependence of Q, the external and internal energies need to be properly decomposed, and temperature quantum correction should be performed. For both vibrational modes, Q shows a temperature dependence Q ∼ T−α, where α > 1 when below Debye temperature due to quantum effects, and Q gradually recovers the classical T−1 dependence when above Debye temperature. Our temperature dependence is in contrast to prior studies that suggested Q ∼ T−β, where 0 < β < 1. The observed size and temperature dependencies by us have many deviations from existing classical theories of energy dissipation, possibly due to phonon confinement effects in these nanostructures and temperature quantum effects.
Optical probe of strong correlations in LaNiO3 thin films
Authors: Stewart M. K. , Liu Jian , Smith R. K. , Chapler B. C. , Yee C.-H. , Baumbach R. E. , Maple M. B. , Haule K. , Chakhalian J. , Basov D. N.
Published: August 2011

The optical properties of LaNiO3 thin films are investigated over a wide energy and temperature range. Thin films of varying thickness were grown by pulsed laser deposition on LaAlO3 and SrTiO3 substrates. The optical conductivity data of the films reveal a number of interband transitions above 1 eV, which are in good agreement with band structure calculations. No well defined Drude peak is observed; however, in stark contrast with local-density approximation theory predicting a finite density of states at the Fermi energy. This experimental finding of a vanishing Drude spectral weight, compared to a finite electron kinetic energy obtained from band structure calculations, highlights the importance of strong electronic correlations in LaNiO3.
Replica exchange molecular dynamics of the thermodynamics of fibril growth of Alzheimer's Aβ42 peptide
Authors: Han Ming , Hansmann Ulrich H. E.
Published: August 2011

The growth of amyloid fibrils is studied by replica exchange molecular dynamics in an implicit solvent. Our data indicate that extremely long simulation times (at least a few hundred ns) are necessary to study the thermodynamics of fibril elongation in detail. However some aspects of the aggregation process are already accessible on the time scales available in the present study. A peak in the specific heat indicates a docking temperature of Tdock ≈ 320 K. Irreversible locking requires lower temperatures with the locking temperature estimated as Tlock ≈ 280 K. In our simulation the fibril grows from both sides with the C-terminal of the incoming monomer attaching to the C-terminal of the peptides in the fibril forming a β-sheet on the fibril edge. Our simulation indicates that the C-terminal is crucial for aggregation.
Increasing the energy dynamic range of solid-state nuclear track detectors using multiple surfaces
Authors: Zylstra A. B. , Rinderknecht H. G. , Sinenian N. , Rosenberg M. J. , Manuel M. , Séguin F. H. , Casey D. T. , Frenje J. A. , Li C. K. , Petrasso R. D.
Published: August 2011

Solid-state nuclear track detectors, such as CR-39, are widely used in physics and in many inertial confinement fusion (ICF) experiments. In the ICF experiments, the particles of interest, such as D3He-protons, have ranges of order of the detector thickness. In this case, the dynamic range of the detector can be extended by recording data on both the front and back sides of the detector. Higher energy particles which are undetectable on the front surface can then be measured on the back of the detector. Studies of track formation under the conditions on the front and back of the detector reveal significant differences. Distinct front and back energy calibrations of CR-39 are therefore necessary and are presented for protons. Utilizing multiple surfaces with additional calibrations can extend the range of detectable energies on a single piece of CR-39 by up to 7-8 MeV. The track formation process is explored with a Monte Carlo code, which shows that the track formation difference between front and back is due to the non-uniform ion energy deposition in matter.
On the periodic orbits and the integrability of the regularized Hill lunar problem
Authors: Llibre Jaume , Roberto Luci Any
Published: August 2011

The classical Hill's problem is a simplified version of the restricted three-body problem where the distance of the two massive bodies (say, primary for the largest one and secondary for the smallest one) is made infinity through the use of Hill's variables. The Levi-Civita regularization takes the Hamiltonian of the Hill lunar problem into the form of two uncoupled harmonic oscillators perturbed by the Coriolis force and the Sun action, polynomials of degree 4 and 6, respectively. In this paper, we study periodic orbits of the planar Hill problem using the averaging theory. Moreover, we provide information about the C1 integrability or non-integrability of the regularized Hill lunar problem.
Dissociative double ionization of 1-bromo-2-chloroethane irradiated by an intense femtosecond laser field
Authors: Yang Yan , Fan Lulu , Sun Shengzhi , Zhang Jian , Chen Yuting , Zhang Shian , Jia Tianqing , Sun Zhenrong
Published: August 2011

The dissociative double ionization and multi-photon ionization of 1-bromo-2-chloroethane (BCE) irradiated by the 800 nm femtosecond laser field have been investigated by dc-slice imaging technology. The charged parent ion ratio [BCE2+]/[BCE+] was measured, and the corresponding ionization process including non-sequential double ionization and sequential double ionization was analyzed. The sliced images of different photo-dissociated ions were detected, and the corresponding kinetic energy release (KER) distributions were calculated and extracted. Furthermore, the dissociative double ionization channels, attributed to the cleavage of the C–C, C–Br, and C–Cl bonds by the Coulombic repulsive forces, were discussed, and the revised equilibrium distance ${R_e ^* }$Re*, the energy ratio Eexp/Ecoul, and the value $a = \sqrt {R_e ^* } /(E_{\exp } /E_{coul})$a=Re*/(Eexp/Ecoul) were calculated.
Nanoscale multiplane shear and twin deformation in nanowires and nanocrystalline solids
Authors: Ovid'ko I. A.
Published: August 2011

A special physical micromechanism/mode of twin deformation in nanowires and nanocrystalline (NC) solids is suggested and theoretically described. This mode represents a nanoscale multiplane shear (NMS) defined as an ideal shear occurring within a nanometer-sized volume. We calculated the energy and stress characteristics of nanoscale twin deformation through NMS in Cu nanowires and NC Cu. It is shown that this deformation mode can occur in NC solids and defect-free nanowires at high stresses.
Effect of Bi2O3 on structural, optical, and other physical properties of semiconducting zinc vanadate glasses
Authors: Punia R. , Kundu R. S. , Hooda J. , Dhankhar S. , Dahiya Sajjan , Kishore N.
Published: August 2011

Zinc bismuth vanadate glasses with compositions 50V2O5-xBi2O3-(50-x) ZnO have been prepared using a conventional melt-quenching method and the solubility limit of Bi2O3 in zinc vanadate glass system has been investigated using x-ray diffraction. Density has been measured using Archimedes’ principle; molar volume (Vm) and crystalline volumes (Vc) have also been estimated. With an increase in Bi2O3 content, there is an increase in density and molar volume of the glass samples. The glass transition temperature (Tg) and Hurby coefficient (Kgl) have been determined using differential scanning calorimetry (DSC) and are observed to increase with increase in Bi2O3 content (i.e., x), up to x = 15, thereby indicating the structural modifications and increased thermal stability of zinc vanadate glasses on addition of Bi2O3. FTIR spectra have been recorded and the analysis of FTIR shows that the structure depends upon the Bi2O3 content in the glass compositions. On addition of Bi2O3 into the zinc vanadate system, the structure of V2O5 changes from VO4 tetrahedral to VO5 trigonal bi-pyramid configuration. The optical parameters have been calculated by using spectroscopic ellipsometry for bulk oxide glasses (perhaps used first time for bulk glasses) and optical bandgap energy is found to increase with increase in Bi2O3 content.
Voltage dependent photocurrent of thin film hematite electrodes
Authors: Klahr Benjamin M. , Hamann Thomas W.
Published: August 2011

The current density (J) vs. applied voltage (V) curves of thin-film hematite electrodes under illumination exhibit non-ideal behavior; as a result, very poor fill factors and photocurrent densities are generally observed. A simple model is presented to describe the photocurrent density behavior of hematite photoelectrodes, which assumes only drift collection of holes in a uniform electric field. Excellent agreement is found between the model and experimental results. Use of this model provides important insight into the limitations of hematite electrodes as well as strategies to achieve improved efficiency.
The effect of the hydrostatic pressure on the electromechanical properties of ferroelectric rhombohedral single crystals Pb(Mg1/3Nb2/3)-Pb(In1/2Nb1/2)-PbTiO3
Authors: Gao Junjie , Xu Zhuo , Li Fei , Zhang Chonghui , Liu Yi , Liu Gaomin , He Hongliang
Published: August 2011

The electromechanical properties of rhombohedral single crystals Pb(Mg1/3Nb2/3)-Pb(In1/2Nb1/2)-PbTiO3 (PMN-PIN-PT) were investigated under hydrostatic pressure from 0.1 to 456 MPa. Due to pressure-induced morphotropic phase boundary moving, the piezoelectric coefficients and electromechanical coupling factors of PMN-PIN-PT crystals were found to decrease by ∼10% and ∼2%, respectively. The mechanical quality factor Q was found to dramatically decrease, because the domain wall motion and friction between vibrator and pressure-transmitting fluid were enhanced under hydrostatic pressure. On the other hand, the pressure induced depolarization and phase transition were not observed in the experimental pressure range.
Self-integrating inductive loop for measuring high frequency pulses
Authors: Rojas-Moreno Mónica V. , Robles Guillermo , Martínez-Tarifa Juan M. , Sanz-Feito Javier
Published: August 2011

High frequency pulses can be measured by means of inductive sensors. The main advantage of these sensors consists of non-contact measurements that isolate and protect measuring equipment. The objective of this paper is to present the implementation of an inductive sensor for measuring rapidly varying currents. It consists of a rectangular loop with a resistor at its terminals. The inductive loop gives the derivative of the current according to Faraday's law and the resistor connected to the loop modifies the sensor's frequency response to obtain an output proportional to the current pulse. The self-integrating inductive sensor was validated with two sensors, a non-inductive resistor and a commercial high frequency current transformer. The results were compared to determine the advantages and drawbacks of the probe as an adequate inductive transducer.
Differential responses of human liver cancer and normal cells to atmospheric pressure plasma
Authors: Gweon Bomi , Kim Mina , Bee Kim Dan , Kim Daeyeon , Kim Hyeonyu , Jung Heesoo , H. Shin Jennifer , Choe Wonho
Published: August 2011

When treated by atmospheric pressure plasma, human liver cancer cells (SK-HEP-1) and normal cells (THLE-2) exhibited distinctive cellular responses, especially in relation to their adhesion behavior. We discovered the critical threshold voltage of 950 V, biased at the electrode of the micro-plasma jet source, above which SK-HEP-1 started to detach from the substrate while THLE-2 remained intact. Our mechanical and biochemical analyses confirmed the presence of intrinsic differences in the adhesion properties between the cancer and the normal liver cells, which provide a clue to the differential detachment characteristics of cancer and normal cells to the atmospheric pressure plasma.
Admissible shock waves and shock-induced phase transitions in a van der Waals fluid
Authors: Zhao Nanrong , Mentrelli Andrea , Ruggeri Tommaso , Sugiyama Masaru
Published: August 2011

A complete classification of shock waves in a van der Waals fluid is undertaken. This is in order to gain a theoretical understanding of those shock-related phenomena as observed in real fluids which cannot be accounted for by the ideal gas model. These relate to admissibility of rarefaction shock waves, shock-splitting phenomena, and shock-induced phase transitions. The crucial role played by the nature of the gaseous state before the shock (the unperturbed state), and how it affects the features of the shock wave are elucidated. A full description is given of the characteristics of shock waves propagating in a van der Waals fluid. The strength of these shock waves may range from weak to strong. The study is carried out by means of the theory of hyperbolic systems supported by numerical calculations.
Structural and semiconductor-to-metal transitions of double-perovskite cobalt oxide Sr2−xLaxCoTiO6−δ with enhanced thermoelectric capability
Authors: Sugahara Tohru , Ohtaki Michitaka
Published: August 2011

The thermoelectric properties of double-perovskite oxide Sr2−xLaxCoTiO6−δ were revealed to vary anomalously with the La concentration, plausibly due to a structural transition found in this study. Although the temperature dependence of the resistivity and thermopower of the present oxide showed a semiconductor-to-metal transition similar to those observed for other perovskite-related Co oxides such as Sr1−xYxCoO3−δ, the transition temperature was more than 350 K higher, implying considerable stabilization of the low-spin state of Co ions in the double-perovskite oxide. Consequently, the operating temperature range of the oxide for potential thermoelectric applications was significantly expanded toward higher temperatures.