bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of shear rupture on aggregate scale formation in sea ice
Authors: Wilchinsky Alexander V. , Feltham Daniel L. , Hopkins Mark A.
Published: October 2010

A discrete element model is used to study shear rupture of sea ice under convergent wind stresses. The model includes compressive, tensile, and shear rupture of viscous elastic joints connecting floes that move under the action of the wind stresses. The adopted shear rupture is governed by Coulomb’s criterion. The ice pack is a 400 km long square domain consisting of 4 km size floes. In the standard case with tensile strength 10 times smaller than the compressive strength, under uniaxial compression the failure regime is mainly shear rupture with the most probable scenario corresponding to that with the minimum failure work. The orientation of cracks delineating formed aggregates is bimodal with the peaks around the angles given by the wing crack theory determining diamond‐shaped blocks. The ice block (floe aggregate) size decreases as the wind stress gradient increases since the elastic strain energy grows faster leading to a higher speed of crack propagation. As the tensile strength grows, shear rupture becomes harder to attain and compressive failure becomes equally important leading to elongation of blocks perpendicular to the compression direction and the blocks grow larger. In the standard case, as the wind stress confinement ratio increases the failure mode changes at a confinement ratio within 0.2–0.4, which corresponds to the analytical critical confinement ratio of 0.32. Below this value, the cracks are bimodal delineating diamond shape aggregates, while above this value failure becomes isotropic and is determined by small‐scale stress anomalies due to irregularities in floe shape.
Recovery of stratospheric ozone in calculations by the Center for Climate System Research/National Institute for Environmental Studies chemistry‐climate model under the CCMVal‐REF2 scenario and a no‐climate‐change run
Authors: Akiyoshi H. , Yamashita Y. , Sakamoto K. , Zhou L. B. , Imamura T.
Published: September 2010

Return times to 1980 values of ozone and the halogen concentrations in the future atmosphere were examined using the outputs of the Center for Climate System Research/National Institute for Environmental Studies chemistry‐climate model (CCM). The CCM calculation for the future atmosphere was performed for the period of 1975–2100 under a future scenario of time‐varying halogens, greenhouse gases, and sea surface temperatures for chemistry‐climate model validation (CCMVal‐REF2 scenario). A sensitivity test of a no‐climate‐change run for the future atmosphere was also performed, in which the concentrations of CO2, CH4, and N2O were fixed at those for 1975, and the sea surface temperature was fixed at that for the 1970–1979 mean, while the halogen concentrations were changed following the REF2 scenario. A comparison of the return time to 1980 values in these two runs was made. The return times of the halogen concentrations and column ozone in the extratropics for the REF2 run are earlier than those for the no‐climate‐change run, influenced by an enhancement of the meridional circulation and stratospheric cooling in the atmosphere. In the tropics, the column ozone of the REF2 run shows a second decrease after 2050, influenced by a stronger upward motion in the future atmosphere than in the present atmosphere. Trends in the zonal mean ozone concentration, zonal mean temperature, zonal mean zonal wind, Eliassen‐Palm (EP) flux, EP flux divergence, vertical component of the residual mean meridional circulation, and chemical forcing to the ozone concentration are examined in the periods of 2000–2050 and 2051–2100. These trends in the dynamical and chemical factors explain the earlier return times of halogens and ozone in the extratropics of the REF2 run than in the no‐climate‐change run. In the no‐climate‐change run, a better correlation between the return time of column ozone to the 1980 level and that of the lower stratospheric halogen concentration is calculated for the Southern Hemisphere corresponding to the facts that the ozone concentrations in the Southern Hemisphere lower stratosphere are more controlled by chlorine and bromine chemistries than those in the Northern Hemisphere.
Impact of the Madden‐Julian Oscillation on the intraseasonal forecast skill of the North Atlantic Oscillation
Authors: Lin Hai , Brunet Gilbert , Fontecilla Juan Sebastian
Published: October 2010

Using the output of the intraseasonal hindcast experiment conducted with the GEM global atmospheric model during 24 extended winters, the association between the forecast skill of the NAO and the amplitude and phase of the MJO in the initial condition is investigated. It is found that with a lead time up to about one month the NAO forecast skill is significantly influenced by the existence of the MJO signal in the initial condition. A strong MJO leads to a better NAO forecast skill than a weak MJO. An initial state with an MJO phase corresponding to a dipole tropical convection anomaly in the eastern Indian Ocean and western Pacific favors a more skillful NAO forecast than an MJO phase with a single tropical convection anomaly near 120°E. These results indicate that it is possible to increase the skill of the NAO and the extratropical surface air temperature intraseasonal forecast with an improved tropical initialization, a better prediction of the tropical MJO and a better representation of the tropical‐extratropical interaction in dynamical models.
Deep‐water bathymetric features imaged by spaceborne SAR in the Gulf Stream region
Authors: Li Xiaofeng , Yang Xiaofeng , Zheng Quanan , Pietrafesa Leonard J. , Pichel William G. , Li Ziwei , Li Xiaoming
Published: October 2010

Deep‐water (>500 m) oceanic bathymetric features are frequently observed in RADARSAT‐1 SAR images in the Gulf Stream (GS) region. They are imaged apparently because of the unique environmental conditions in the region, oceanographically characterized by a strong GS current (2 ms−1) and favorable ocean stratification. SAR image analysis shows the basic characteristics of these bathymetric features. A coincident sea surface temperature image shows that the bathymetric feature is only “visible” by SAR within the GS pathway. The dominant wavelength of the wave‐like feature is about 2.3 km and their crests are perpendicular to the GS axis. Shipboard sounding measurements confirm the SAR observation. A theoretical consideration of the ocean current and corrugated bathymetry interaction in a 3‐layer ocean is presented. Using representative ocean density profile data and the GS current data, we analyze the requirements for the generation and upward propagation of the disturbance induced by the current‐bathymetry interaction.
Oxygen in the Southern California Bight: Multidecadal trends and implications for demersal fisheries
Authors: McClatchie S. , Goericke R. , Cosgrove R. , Auad G. , Vetter R.
Published: October 2010

Reports of hypoxic conditions (oxygen <1.5 ml L−1) off the U.S. west coast over the last two decades led us to investigate hypoxia in the Southern California Bight (SCB) and its potential impacts on fisheries. The secular trend in hypoxia in the SCB over the last 57 years is not monotonic, and reversed trend in the mid‐1980s, bringing oxygen concentrations back to levels measured in the late 1950s to early 1960s. Thirty‐seven percent of the rockfish (Sebastes spp.) habitat in the Cowcod Conservation Area at 240–350 m depths suffers exposure to hypoxia in the summer of normal years. If current trends in shoaling of low oxygen water continue for another 20 years, rather than reversing as happened previously, we predict loss of 18% of the habitat with 55% of the total habitat exposed to hypoxia.
GCR access to the Moon as measured by the CRaTER instrument on LRO
Authors: Case A. W. , Spence H. E. , Golightly M. J. , Kasper J. C. , Blake J. B. , Mazur J. E. , Townsend L. W. , Zeitlin C. J.
Published: October 2010

Recent modeling efforts have yielded varying and conflicting results regarding the possibility that Earth's magnetosphere is able to shield energetic particles of >10 MeV at lunar distances. This population of particles consists of galactic cosmic rays as well as energetic particles that are accelerated by solar flares and coronal mass ejections. The Cosmic Ray Telescope for the Effects of Radiation (CRaTER) onboard the Lunar Reconnaissance Orbiter is in orbit about the Moon and is thus able to directly test these modeling results. Over the course of a month, CRaTER samples the upstream solar wind as well as various regions of Earth's magnetotail. CRaTER data from multiple lunations demonstrate that Earth's magnetosphere at lunar distances produces no measurable influence on energetic particle flux, even at the lowest energies (>14 MeV protons) where any effect should be maximized. For particles with energies of 14–30 MeV, we calculate an upper limit (determined by counting statistics) on the amount of shielding caused by the magnetosphere of 1.7%. The high energy channel (>500 MeV) provides an upper limit of 3.2%.
Cassini INMS observations of neutral molecules in Saturn's E‐ring
Authors: Perry Mark E. , Teolis Ben , Smith H. Todd , McNutt Ralph L. , Fletcher Greg , Kasprzak Wayne , Magee Brian , Mitchell Donald G. , Waite J. Hunter
Published: October 2010

In 2008, the Cassini ion neutral mass spectrometer (INMS) investigation made in situ measurements of neutral species near Saturn's equatorial plane within 0.5 Saturn radii (RS) of the orbit of Enceladus. After removing the large background and modeling to interpret instrumental effects, the data provide rough constraints on the neutral distribution and composition. These data show an azimuthal asymmetry in the neutral densities and provide measurements used to compare to simulations of neutral H2O emitted from Enceladus. Far from Enceladus, the neutral water densities, at a few times 103 molecules/cm3, are near the detection limit of INMS. Near Enceladus, but outside of the plumes and north of the equatorial plane, the INMS detects particles within 5000 km of Enceladus, with the density increasing to approximately 105 molecules/cm3 at the equatorial plane. The observations also show CO2 in the form of its dissociated product, CO. On the basis of the spatial distribution of CO2 counts, the scale height of the neutral cloud above and below the equatorial plane is less than 7000 km. Far from Enceladus, the concentration of CO2 with respect to H2O increases, a consequence of the predicted decline in H2O density. Relatively high counts at 2 amu are infrequently observed. These measurements indicate H2 released during ice‐grain impacts and provide a constraint on the frequency and distribution of small ice grains.
Thin magnetosheath as a consequence of the magnetopause deformation: THEMIS observations
Authors: Jelínek K. , Němeček Z. , Šafránková J. , Shue J.‐H. , Suvorova A. V. , Sibeck D. G.
Published: October 2010

This paper presents a simultaneous observation of the bow shock and magnetopause by THEMIS probes that allows determination of the actual magnetosheath thickness at the subsolar point. Moreover, Geotail located at the dusk dayside magnetosheath registered a brief excursion to the magnetosphere in this time. The spacecraft configuration reveals a significant deformation of the magnetopause surface that locally decreases its curvature radius. The highly curved magnetopause results in the decrease of the magnetosheath thickness to about half of its standard value in a particular observation point. The observed phenomenon is attributed to a rotation of the interplanetary magnetic field (IMF). Although it is generally expected that the bow shock and magnetopause move in accord, being driven mainly by the solar wind dynamic pressure, we suggest that the local and transient thinning of the magnetosheath can result from different responses of its boundaries to a sudden change of the pressure and/or IMF orientation.
Effects of the low‐latitude ionospheric boundary condition on the global magnetosphere
Authors: Merkin V. G. , Lyon J. G.
Published: October 2010

In common treatment of magnetosphere‐ionosphere coupling at high latitudes, the ionosphere is represented by a thin conducting spherical shell, which closes field‐aligned currents generated in the magnetosphere. In this approach, the current continuity yields a Poisson equation for the electrostatic potential associated with the ionospheric convection pattern. Solution of the Poisson equation then provides a means of self‐consistently describing magnetospheric and ionospheric plasma convection with a feedback of one on the other. While the high‐latitude ionospheric convection is driven by the solar wind and magnetosphere interaction, at lower latitudes atmospheric neutral winds start to dominate. The question that arises then is whether and how midlaltitude and low‐latitude ionospheric convection affects high‐latitude ionospheric and magnetospheric convection. In global magnetospheric models, ionospheric convection equatorward of the low‐latitude boundary is excluded from the simulation domain. However, the boundary condition applied at that boundary to the electrostatic potential may be used as a proxy of this convection. In this paper, we explore effects that different idealized low‐latitude boundary conditions have on the magnetospheric configuration simulated by the Lyon‐Fedder‐Mobarry global magnetohydrodynamic model. To this end, we perform a number of idealized simulations different only in the low‐latitude ionospheric boundary condition used. We find that the behavior of the system can be influenced rather significantly by the different boundary conditions, which is expressed by changes in the evolution of the polar cap potential, global magnetospheric convection, and plasma pressure distribution in the magnetotail and on the dayside. The differences in the cross‐polar cap potential can reach up to >10%, dependent on the boundary condition used. In the magnetosphere the low‐latitude ionospheric boundary condition affects the strength and location of the plasma outflow from the distant tail x‐line and the subsequent earthward convection. Changes in the plasma pressure distribution on the nightside are accompanied by noticeable differences in the shape of the magnetotail. We confirm that the changes in the magnetospheric and ionospheric configuration are not just temporal deviations of the system from the same average dynamical state by considering 1 h averages of the magnetospheric flow and pressure distribution. These results verify that the simulated system reaches similar but distinctly different dynamical states dependent on the low‐latitude boundary condition applied.
Comparison of TWINS images of low‐altitude emission of energetic neutral atoms with DMSP precipitating ion fluxes
Authors: Bazell D. , Roelof E. C. , Sotirelis T. , Brandt P. C. , Nair H. , Valek P. , Goldstein J. , McComas D.
Published: October 2010

The brightest energetic neutral atom (ENA) intensity viewed by spacecraft in high‐inclination Earth orbit is from low‐altitude emission (LAE). It is a prominent feature in the stereo ENA images obtained by cameras on the NASA TWINS 1/2 Mission of Opportunity. This emission is produced by energetic magnetospheric ions precipitating into the atomic oxygen exosphere at latitudes near the auroral zones at altitudes ∼300 km. The ions undergo multiple atomic collisions including charge exchange of ions and stripping of the resulting neutrals. Consequently, this is a “thick target” process. We introduce a “thick‐target” approximation that allows us to extract the shape of the spatially averaged spectra of the precipitating ions from the ENA spectra in the TWINS 1/2 pixels viewing the LAE from near their orbital apogees. These ENA‐extracted ion spectra are compared with in situ precipitating ion spectra measured concurrently by DMSP satellites (F15 and F16) at ∼825 km altitude, while they are passing directly over the LAE regions in the TWINS 1/2 images. We obtain good agreement between the shape of the ENA‐extracted and in situ ion spectra from three distinct precipitation regions over energies from 2 to 32 keV (assuming precipitating protons). The absolute normalization of the ENA‐extracted and in situ spectra depends upon the TWINS viewing geometry because the ENA LAE source is not resolved by the imager. None of the spectral shapes obtained is consistent with a simple thermal intensity spectrum with kT = 5 keV.
West African Monsoon water cycle: 2. Assessment of numerical weather prediction water budgets
Authors: Meynadier R. , Bock O. , Gervois S. , Guichard F. , Redelsperger J.‐L. , Agustí‐Panareda A. , Beljaars A.
Published: September 2010

Water budgets from European Centre for Medium‐Range Weather Forecasts (ECMWF) Re‐Analysis (ERA)‐Interim and National Centers for Environmental Prediction (NCEP) Reanalysis I and II are intercompared and compared to GPS precipitable water and to the 6 year hybrid budget data set described in part 1 of this study. Deficiencies are evidenced in the reanalyses which are most pronounced over the Sahel. Results from operational models (ECMWF Integrated Forecast System, NCEP Global Forecast System, and ARPEGE‐Tropiques) and the special ECMWF African Monsoon Multidisciplinary Analyses reanalysis confirm and help understanding these findings. A bias (∼1–2 mm d−1) in precipitation and evapotranspiration leads to an unrealistic view of West Africa as a moisture source during the summer. North of the rainband (13°N–16°N), moisture flux convergence (MFC) shows a minimum in the NCEP models and divergence in the ECMWF models not consistent with the hybrid data set. This feature, added to presence of a deep layer of northerly dry air advected at midlevels (800–400 hPa), is thought to block the development of deep convection in the models and the northward propagation of the monsoonal rainband. The northerly flow is part of a shallow meridional circulation that is driven by the Saharan heat low. This circulation appears too strong in some of the models, a possible consequence of the too‐approximate representation of physical processes and land surface properties over the Sahel. In most of the models, evapotranspiration shows poor connection with precipitation. This is linked with large analysis increments in precipitable water, soil moisture, and MFC. Despite the large biases affecting the water budget components in the models, temporal variations (seasonal and interannual) might nevertheless be recovered with reasonable accuracy.
Effects of Eicosapentaenoic Acid (EPA) Treatment on Insulin Sensitivity in an Animal Model of Diabetes: Improvement of the Inflammatory Status
Authors: Figueras Maite , Olivan Mireia , Busquets Sílvia , López‐Soriano Francisco J. , Argilés Josep M.
Published: September 2010

In addition to decreased insulin sensitivity, diabetes is a pathological condition associated with increased inflammation. The ω‐3 fatty acids have been proposed as anti‐inflammatory agents. Thus, the major goal of this study was to analyze the effects of fatty acid supplementation on both insulin sensitivity and inflammatory status in an animal model of type 2 diabetes. Diabetic rats (Goto‐Kakizaki model) were treated with eicosapentaenoic acid (EPA) or linoleic acid at 0.5 g/kg body weigh (bw) dose. In vivo incorporation of 14C‐triolein into adipose tissue was improved by the ω‐3 administration. In vitro incubations of adipose tissue slices from EPA‐treated rats showed an increase in 14C‐palmitate incorporation into the lipid fraction. These observations were linked with a decreased rate of fatty acid oxidation. EPA treatment resulted in a decreased fatty acid oxidation in incubated strips from extensor digitorum longus (EDL) muscles. The changes in lipid utilization were associated with a decrease in insulin plasma concentration, suggesting an improvement in insulin sensitivity. These changes in lipid metabolism were associated with an activation of AMP‐activated protein kinase (AMPK) in white adipose tissue. In addition, EPA treatment resulted in a decreased content of peroxisome proliferator‐activated receptor‐α (PPARα) and PPARδ and in increased GLUT4 expression in skeletal muscle. Moreover, EPA increased 2‐deoxy‐D‐[14C]glucose (2‐DOG) uptake in C2C12 myotubes, suggesting an improvement in glucose metabolism. Concerning the inflammatory status, EPA treatment resulted in a decreased gene expression for both tumor necrosis factor‐α (TNF‐α) and interleukin‐6 (IL‐6) both in skeletal muscle and adipose tissue. The data suggest that EPA treatment to diabetic rats clearly improves lipid metabolism although the evidences on insulin sensitization are less clear.
Corrected High–Frame Rate Anchored Ultrasound With Software Alignment
Authors: Miller Amanda L. , Finch Kenneth B.
Published: October 2010

Purpose

To improve lingual ultrasound imaging with the Corrected High Frame Rate Anchored Ultrasound with Software Alignment (CHAUSA; Miller, 2008) method.

Method

A production study of the IsiXhosa alveolar click is presented. Articulatory-to-acoustic alignment is demonstrated using a Tri-Modal 3-ms pulse generator. Images from 2 simultaneous data collection paths, using dominant ultrasound technology and the CHAUSA method, are compared. The probe stabilization and head movement correction paradigm is demonstrated.

Results

The CHAUSA method increases the frame rate from the standard National Television System Committee (NTSC) video rate (29.97) to the ultrasound internal machine rate—in this case, 124 frames per second (fps)—by using Digital Imaging and Communications in Medicine (DICOM; National Electrical Manufacturers Association, 2008) data transfer. DICOM avoids spatiotemporal inaccuracies introduced by dominant ultrasound export techniques. The data display alignment of the acoustic and articulatory signals to the correct high–frame rate (FR) frame (±4 ms at 124 fps).

Conclusions

CHAUSA produces high-FR, high-spatial-quality ultrasound images, which are head corrected to 1 mm. The method reveals tongue dorsum retraction during the posterior release of the alveolar click and tongue tip recoil following the anterior release of the alveolar click, both of which were previously undetectable. CHAUSA visualizes most of the tongue in studies of dynamic consonants with a major reduction in field problems, opening up important areas of speech research.
True knot of the umbilical cord: a difficult prenatal ultrasonographic diagnosis
Authors: Sepulveda W. , Shennan A. H. , Bower S. , Nicolaidis P. , Fisk N. M.
Published: October 2010

We examined retrospectively the use of ultrasonography in 18 cases in which a true knot of the umbilical cord was found at delivery. All women had a normal second trimester scan in which no cord abnormality was detected. Thirteen (72%) also had third‐trimester color Doppler ultrasonography, at which time the cord anomaly was again missed. In one of these cases the diagnosis could have been made with color flow imaging, but the abnormal pattern was mistaken instead for multiple loops of cord. On the other hand, the diagnosis of true knot was considered prenatally in two cases, but not confirmed at delivery, when only a prominent false knot was found in one and a normal cord in the other. We conclude that true knots of the umbilical cord do not have a characteristic appearance in utero and therefore are easily missed at routine prenatal ultrasonography. Copyright © 1995 International Society of Ultrasound in Obstetrics and Gynecology
IUPAC-NIST Solubility Data Series. 89. Alkali Metal Nitrates. Part 1. Lithium Nitrate
Authors: Orlova Violetta Timofeevna
Published: October 2010

This paper is the first part in the nitrate solubility volume. The solubility data for lithium nitrate are reviewed. Where appropriate, binary, ternary, and multicomponent systems are critically evaluated. Most of the solubility results were obtained in water or aqueous solutions. The solubility in ethanol and in alcohol+water solvent mixtures is also included. All data were critically examined for their reliability. The best values were selected on the basis of critical evaluations and presented in tabular form. Fitting equations and plots are also provided. The quantities, units, and symbols used are in accord with IUPAC recommendations. The original data have been reported and, if necessary, transferred into the units and symbols recommended by IUPAC. The literature on solubility data was researched through 2007.
Heat Capacity of Room-Temperature Ionic Liquids: A Critical Review
Authors: Paulechka Yauheni U.
Published: October 2010

Experimental data on heat capacity of room-temperature ionic liquids in the liquid state were compiled and critically evaluated. The compilation contains data for 102 aprotic ionic liquids from 63 literature references and covers the period of time from 1998 through the end of February 2010. Parameters of correlating equations for temperature dependence of the heat capacities were developed.
Oxygen plasma treatment for reducing hydrophobicity of a sealed polydimethylsiloxane microchannel
Authors: Tan Say Hwa , Nguyen Nam-Trung , Chua Yong Chin , Kang Tae Goo
Published: October 2010

Rapid prototyping of polydimethylsiloxane (PDMS) is often used to build microfluidic devices. However, the inherent hydrophobic nature of the material limits the use of PDMS in many applications. While different methods have been developed to transform the hydrophobic PDMS surface to a hydrophilic surface, the actual implementation proved to be time consuming due to differences in equipment and the need for characterization. This paper reports a simple and easy protocol combining a second extended oxygen plasma treatments and proper storage to produce usable hydrophilic PDMS devices. The results show that at a plasma power of 70 W, an extended treatment of over 5 min would allow the PDMS surface to remain hydrophilic for more than 6 h. Storing the treated PDMS devices in de-ionized water would allow them to maintain their hydrophilicity for weeks. Atomic force microscopy analysis shows that a longer oxygen plasma time produces a smoother surface.
Supersymmetry of the planar Dirac–Deser–Jackiw–Templeton system and of its nonrelativistic limit
Authors: Horváthy Peter A. , Plyushchay Mikhail S. , Valenzuela Mauricio
Published: October 2010

The planar Dirac and the topologically massive vector gauge fields are unified into a supermultiplet involving no auxiliary fields. The super-Poincaré symmetry emerges from the osp(1∣2) supersymmetry realized in terms of the deformed Heisenberg algebra underlying the construction. The nonrelativistic limit yields spin 1/2 as well as new, spin 1 “Lévy–Leblond-type” equations which, together, carry an N=2 super-Schrödinger symmetry. Part of the latter has its origin in the universal enveloping algebra of the super-Poincaré algebra.
DNA separation by cholesterol-bearing pullulan nanogels
Authors: Kondo Keisuke , Kaji Noritada , Toita Sayaka , Okamoto Yukihiro , Tokeshi Manabu , Akiyoshi Kazunari , Baba Yoshinobu
Published: October 2010

We present an application of a novel DNA separation matrix, cholesterol-bearing pullulan (CHP) nanogels, for microchip electrophoresis. The solution of the CHP showed a unique phase transition around 30 mg/ml and formed gel phase over this critical concentration. This gel phase consists of the weak hydrophobic interactions between the cholesterols could be easily deformed by external forces, and thus, loading process of the CHP nanogels into microchannels became easier. The high concentration of the CHP nanogels provided excellent resolutions especially for small DNA fragments from 100 to 1500 bp. The separation mechanism was discussed based on Ogston and Reptation models which had developed in gels or polymer solutions. The result of a single molecule imaging gave us an insight of the separation mechanism and the nanogel structures as well.
Herceptin functionalized microfluidic polydimethylsiloxane devices for the capture of human epidermal growth factor receptor 2 positive circulating breast cancer cells
Authors: Thierry Benjamin , Kurkuri Mahaveer , Shi Jun Yan , Lwin Lwin Ei Mon Phyo , Palms Dennis
Published: October 2010

Building on recent breakthroughs in the field of microfluidic-based capture of rare cancer cells circulating in the blood, the present article reports on the use of Herceptin functionalized PDMS devices designed to efficiently capture from blood cancer cells, overexpressing the tyrosine kinase human epidermal growth factor receptor (HER2). The identification of patients overexpressing HER2 is critical as it typically associates with an aggressive disease course in breast cancer and poor prognosis. Importantly, HER2 positive patients have been found to significantly benefit from Herceptin (Trastuzumab), a humanized monoclonal antibody (MAb) against HER2. Disposable PDMS devices prepared using standard soft lithography were functionalized by the plasma polymerization of an epoxy-containing monomer. The epoxy-rich thin film (AGEpp) thus created could be conjugated with Herceptin either directly or through a polyethylene glycol interlayer. The properties and reactivity toward the monoclonal antibody conjugation of these coatings were determined using x-ray photoelectron spectroscopy; direct conjugation provided a good compromise in reactivity and resistance to biologically nonspecific fouling and was selected. Using the breast cancer cell line SK-BR-3 as a model for cells overexpressing HER2, the immunocapture efficacy of the Herceptin functionalized PDMS was demonstrated in model studies. Validation studies confirmed the ability of the device to efficiently capture (∼80% capture yield) HER2 positive cells from full blood.
Atomic structure and formation mechanism of identically sized Au clusters grown on Si(111)-(7×7) surface
Authors: Wu Yaping , Zhou Yinghui , Zhou Changjie , Zhan Huahan , Kang Junyong
Published: October 2010

Identically sized Au clusters are grown on the Si(111)-(7×7) surface by room temperature deposition of Au atoms and subsequent annealing at low-temperature. The topographical images investigated by in situ scanning tunneling microscopy show a bias-dependent feature. The current-voltage properties measured by scanning tunneling spectroscopy indicate some semiconducting characteristics of the Au adsorbed surface, which is attributable to the saturation of Si dangling bonds. These experimental results, combined with the simulated scanning tunneling microscopy images and the first-principles adsorption energy calculations, show that the Au cluster is most likely to have a Au6Si3 structure. In the Au6Si3 cluster, three adsorbed Au atoms replace the three Si center adatoms, forming a hollow triangle, while the replaced Si atoms and other three Au atoms connect into a hexagon locating within the triangle. The formation mechanism of this atomic configuration is intimately associated with the complicated chemical valences of Au and the specific annealing conditions.
Carbon nanotube with square cross-section: An ab initio investigation
Authors: Autreto P. A. S. , Legoas S. B. , Flores M. Z. S. , Galvao D. S.
Published: October 2010

Recently, Lagos et al. [Nat. Nanotechnol. 4, 149 (2009)] reported the discovery of the smallest possible silver square cross-section nanotube. A natural question is whether similar carbon nanotubes can exist. In this work we report ab initio results for the structural, stability, and electronic properties for such hypothetical structures. Our results show that stable (or at least metastable) structures are possible with metallic properties. They also show that these structures can be obtained by a direct interconversion from SWNT(2,2). Large finite cubanelike oligomers, topologically related to these new tubes, were also investigated.
The single particle dynamics of iodine in the Sachs–Teller regime: An inelastic x-ray scattering study
Authors: Izzo M. G. , Bencivenga F. , Cunsolo A. , Di Fonzo S. , Verbeni R. , De Lorenzo R. Gimenez
Published: October 2010

The high frequency dynamics of liquid iodine has been investigated by deep inelastic x-ray scattering at exchanged wave-vectors (q) ranging from 2.5 to 15 Å−1. The experimental data have been analyzed in the frame of the Sachs–Teller theory of the molecular spectrum while accounting for final state corrections to the lineshape. The performed data analysis carries insights on physical quantities as relevant as the mean rototranslational kinetic energy and the mean square Laplacian of the intermolecular potential. In both cases the measured values are consistent with corresponding theoretical expectations.
A versatile automated sample changer for texture measurements on the high pressure-preferred orientation neutron diffractometer
Authors: Reiche H. M. , Vogel S. C.
Published: October 2010

An automated sample changer with an Eulerian cradle for neutron texture measurements is described. This device has been measuring over 2300 texture and almost 400 powder samples at ambient conditions since it became operational in 2002 for use in the high pressure-preferred orientation diffractometer at the LANSCE neutron scattering facility. Operation for almost a decade resulted in sustained enhancements of mechanics, electronics, and software which significantly improved reliability and resiliency. We also describe in this paper our platform independent computer program POD2K which we use to create publication quality pole figure plots for texture samples.
Ultrastatic space-times
Authors: Sonego Sebastiano
Published: October 2010

Several calculations in conformally static space-times rely on the introduction of an ultrastatic background. I describe the general properties of ultrastatic space-times, and then focus on the problem of whether a given space-time can be ultrastatic, or conformally ultrastatic, in more than one way. I show that the first possibility arises if and only if the space-time contains regions that are products with a Minkowskian factor, and that the second arises if and only it contains regions whose spatial sections are conformal to a product space.
Soft capacitor fibers for electronic textiles
Authors: Gu Jian Feng , Gorgutsa Stephan , Skorobogatiy Maksim
Published: October 2010

A highly flexible, conductive polymer-based fiber with high electric capacitance is reported. The fiber is fabricated using fiber drawing method, where a multimaterial macroscopic preform is drawn into a submillimeter capacitor microstructured fiber. A typical measured capacitance per unit length of our fibers is 60–100 nF/m which is about 3 orders magnitude higher than that of a coaxial cable of a comparable diameter. The fiber has a transverse resistivity of 5 kΩ m. Softness, lightweight, absence of liquid electrolyte, and ease of scalability to large production volumes make the fibers interesting for various smart textile applications.
Exact mapping between system-reservoir quantum models and semi-infinite discrete chains using orthogonal polynomials
Authors: Chin Alex W. , Rivas Ángel , Huelga Susana F. , Plenio Martin B.
Published: October 2010

By using the properties of orthogonal polynomials, we present an exact unitary transformation that maps the Hamiltonian of a quantum system coupled linearly to a continuum of bosonic or fermionic modes to a Hamiltonian that describes a one-dimensional chain with only nearest-neighbor interactions. This analytical transformation predicts a simple set of relations between the parameters of the chain and the recurrence coefficients of the orthogonal polynomials used in the transformation and allows the chain parameters to be computed using numerically stable algorithms that have been developed to compute recurrence coefficients. We then prove some general properties of this chain system for a wide range of spectral functions and give examples drawn from physical systems where exact analytic expressions for the chain properties can be obtained. Crucially, the short-range interactions of the effective chain system permit these open-quantum systems to be efficiently simulated by the density matrix renormalization group methods.
Self-similar blowup solutions to the 2-component Camassa–Holm equations
Authors: Yuen Manwai
Published: October 2010

In this article, we study the self-similar solutions of the 2-component Camassa–Holm equations ρt+uρx+ρux=0, mt+2uxm+umx+σρρx=0, with m=u−α2uxx. By the separation method, we can obtain a class of blowup or global solutions for σ=1 or −1. In particular, for the integrable system with σ=1, we have the global solutions, ρ(t,x)=f(η)/a(3t)1/3 for η2<α2/ξ, ρ(t,x)=0 for η2≥α2/ξ, u(t,x)=ȧ(3t)/a(3t)x, ä(s)−ξ/3a(s)1/3=0,a(0)=a0>0,ȧ(0)=a1, f(η)=ξ−1/ξη2+(α/ξ)2, where η=xa(s)1/3 with s=3t; ξ>0 and α≥0 are arbitrary constants. Our analytical solutions could provide concrete examples for testing the validation and stabilities of numerical methods for the systems.
Negative permittivity and left-handed behavior of doped manganites in millimeter waveband
Authors: Khodzitsky M. K. , Tarapov S. I. , Belozorov D. P. , Pogorily A. M. , Tovstolytkin A. I. , Belous A. G. , Solopan S. A.
Published: October 2010

The “effective plasma frequency” of strontium-doped lanthanum manganite was determined basing on its double negative properties. The zone of high transmission (double negative zone) for spatially partitioned layered manganite specimen, immersed into dielectric matrix, was studied experimentally in millimeter waveband. It turns out that frequency dependence of manganite permittivity is well described by Drude formula, which includes only one parameter—the “effective plasma frequency.” Additionally, the negativity of the refraction index has been directly proved in experiments studying electromagnetic waves refraction in manganite prism.
Origin of flat-band voltage sharp roll-off in metal gate/high-k/ultrathin- SiO2/Si p-channel metal-oxide-semiconductor stacks
Authors: Zheng X. H. , Huang A. P. , Xiao Z. S. , Yang Z. C. , Wang M. , Zhang X. W. , Wang W. W. , Chu Paul K.
Published: October 2010

The origin of the flat band voltage roll-off (VFB roll-off) in metal gate/high-k/ultrathin-SiO2/Si metal-oxide-semiconductor stacks is analyzed and a model describing the role of the dipoles at the SiO2/Si interface on the VFB sharp roll-off is proposed. The VFB sharp roll-off appears when the thickness of the SiO2 interlayer diminishes to below the oxygen diffusion depth. The results derived using our model agree well with experimental data and provide insights to the mechanism of the VFB sharp roll-off.
Carrier recombination mechanisms and efficiency droop in GaInN/GaN light-emitting diodes
Authors: Dai Qi , Shan Qifeng , Wang Jing , Chhajed Sameer , Cho Jaehee , Schubert E. Fred , Crawford Mary H. , Koleske Daniel D. , Kim Min-Ho , Park Yongjo
Published: October 2010

We model the carrier recombination mechanisms in GaInN/GaN light-emitting diodes as R=An+Bn2+Cn3+f(n), where f(n) represents carrier leakage out of the active region. The term f(n) is expanded into a power series and shown to have higher-than-third-order contributions to the recombination. The total third-order nonradiative coefficient (which may include an f(n) leakage contribution and an Auger contribution) is found to be 8×10−29 cm6 s−1. Comparison of the theoretical ABC+f(n) model with experimental data shows that a good fit requires the inclusion of the f(n) term.
Lateral, high-quality, metal-catalyzed semiconductor growth on amorphous and lattice-mismatched substrates for photovoltaics
Authors: Quitoriano Nathaniel J.
Published: October 2010

Solar-derived energy is universally available but is not yet cost-competitive. Next generation solar cells are expected to have high efficiencies, associated with single-crystalline semiconductors, at reduced costs, associated with amorphous substrates. Here we report the growth of high-quality semiconductors (Ge and Si) on amorphous and lattice-mismatched substrates using metal-catalyzed, lateral growth. Using this technique, we engineer the location of crystal nucleation, by controlling the catalyst location, and can thus prevent the formation of grain boundaries, typical when crystals grow together. The results presented here provide a foundation upon which next generation photovoltaics may be built.
Interfacial chemical states of resistance-switching metal/Pr0.7Ca0.3MnO3 interfaces
Authors: Yasuhara R. , Yamamoto T. , Ohkubo I. , Kumigashira H. , Oshima M.
Published: October 2010

The relationship between interfacial chemical states and resistance-switching (RS) behaviors at the metal/Pr0.7Ca0.3MnO3 (PCMO) interfaces has been studied by photoemission spectroscopy and x-ray absorption spectroscopy. For Al/PCMO interfaces that exhibit RS behavior, redox reactions between Al and Mn ions occur at the interface. In sharp contrast, no chemical reactions occur at Pt/PCMO interfaces that do not exhibit RS behavior. These results strongly suggest that the interfacial transition layer due to the redox reactions is responsible for the RS behavior at metal/PCMO interfaces.
Light propagation in a free-standing lithium niobate photonic crystal waveguide
Authors: Geiss R. , Diziain S. , Iliew R. , Etrich C. , Hartung H. , Janunts N. , Schrempel F. , Lederer F. , Pertsch T. , Kley E.-B.
Published: October 2010

We report on the light propagation in a one-line-defect photonic crystal waveguide (W1 PhC WG) patterned into a 450 nm thick free-standing lithium niobate membrane by ion-beam enhanced etching. The Bloch wave vectors and transmission spectrum of this PhC WG were retrieved from optical near-field images. The experimental data show good agreement with simulations performed with the three-dimensional (3D) finite-element method and the 3D finite-difference time-domain method. Those results are promising for the development of integrated optics devices operating at telecom wavelengths and based on free-standing lithium niobate PhC membranes.
Suborbital research hitches a ride on commercial space cruisers
Authors: Matthews Jermey N. A.
Published: October 2010

NASA hires industry to transport scientific payloads bound for microgravity environments.
The evolution of the science museum
Authors: Friedman Alan J.
Published: October 2010

Once resources for the scholar and serious student, science museums are now dedicated to public education. But just how institutions define and meet their educational goals is a continuing story.
Natural and Treated Hectorites/Poly(Sodium Acrylate) Hybrids: Synthesis, Characterization, and Properties
Authors: Mucientes Antonio E. , Santiago Francisca , Carrero Ana , Rivera Carlos
Published: October 2010

Novel hybrids of poly(sodium acrylate) and natural and treated hectorites have been synthesized and characterized by X-ray diffraction, transmission electron microscopy analysis, and FTIR analysis. The thermal stability of these materials was studied. The swelling kinetics obey a Voigt-based equation. The experimental equilibrium water absorbency varies with the clay content and shows a minimum. All the hybrids showed excellent reswelling capability. Water desorption studies demonstrated the existence of ‘free water’ and ‘bound water’ within the polymeric matrix.
Differential expression of microRNAs in porcine placentas on Days 30 and 90 of gestation
Authors: Su Lijie , Zhao Shuhong , Zhu Mengjin , Yu Mei
Published: October 2010

The porcine placenta is classified as a non-invasive epitheliochorial type. To meet the increasing demands for nutrients by the rapidly growing conceptus and/or fetus, the placental microscopic folds undergo significant morphological and biochemical changes during two periods critical for conceptus and/or fetus, namely Days 30–40 and after Day 90 of gestation. MicroRNAs (miRNAs) are a class of small non-coding RNAs that can modulate gene activity by inhibiting the translation or regulation of mRNA degradation. In the present study, we identified 17 differentially expressed miRNAs in porcine placenta on Days 30 and 90 of gestation using a locked nucleic acid (LNA) microRNA array. Stem–loop real-time reverse transcription–polymerase chain reaction confirmed the differential expression of eight selected miRNAs (miR-24, miR-125b, miR-92b, miR-106a, miR-17, let-7i, miR-27a and miR-20). Analysis of targets and the pathways in which these miRNAs are involved revealed that the differentially expressed miRNAs target many genes that are important in various processes, including cell growth, trophoblast differentiation, angiogenesis and formation and maintenance of adherens junctions. The results of the present study suggest potential roles for these differentially expressed miRNAs in porcine placental growth and function.
Efficient system for preservation and regeneration of genetic resources in chicken: concurrent storage of primordial germ cells and live animals from early embryos of a rare indigenous fowl (Gifujidori)
Authors: Nakamura Yoshiaki , Usui Fumitake , Miyahara Daichi , Mori Takafumi , Ono Tamao , Takeda Kumiko , Nirasawa Keijiro , Kagami Hiroshi , Tagami Takahiro
Published: October 2010

The unique accessibility of chicken primordial germ cells (PGCs) during early development provides the opportunity to combine the reproduction of live animals with genetic conservation. Male and female Gifujidori fowl (GJ) PGCs were collected from the blood of early embryos, and cryopreserved in liquid nitrogen for >6 months until transfer. Manipulated GJ embryos were cultured until hatching; fertility tests indicated that they had normal reproductive abilities. Embryos from two lines of White Leghorn (24HS, ST) were used as recipients for chimera production following blood removal. The concentration of PGCs in the early embryonic blood of 24HS was significantly higher than in ST (P < 0.05). Frozen–thawed GJ PGCs were microinjected into the bloodstream of same-sex recipients. Offspring originating from GJ PGCs in ST recipients were obtained with a higher efficiency than those originating from GJ PGCs in 24HS recipients (23.3% v. 3.1%). Additionally, GJ progeny were successfully regenerated by crossing germline chimeras of the ST group. In conclusion, the cryogenic preservation of PGCs from early chicken embryos was combined with the conservation of live animals.
Effects of recipient mouse strain, sex and gonadal status on the outcome of testis tissue xenografting
Authors: Abbasi Sepideh , Honaramooz Ali
Published: October 2010

The aim of the present study was to examine factors that may affect the outcome of testis tissue xenografting. Recipient factors were examined by grafting small fragments of testis tissue from newborn piglets under the back skin of immunodeficient mice of different strains (severe combined immunodeficiency (SCID) v. nude), sex (male v. female) and gonadal status (intact v. gonadectomised) using a factorial design (eight groups; n = 7 mice per group). Recipient mice were killed after 8 months to compare the gross and histological attributes of the recovered grafts. Overall, approximately 94% of grafts were recovered. Gonadectomy of male or female recipients did not affect any of the measured outcomes of testis tissue xenografting, therefore data were pooled. Overall, in terms of sex, male mice and, in terms of strain, SCID mice tended to show higher gross and histological development of grafts. The group of female nude mice had the lowest graft recovery rate (75%) compared with the other groups (95–100%; P < 0.05). The grafts from male SCID mice were, on average the largest and had the highest percentage of spermatozoa-containing seminiferous tubules among all the groups (P < 0.05). These results suggest that male SCID mice provide a suitable recipient model for testis tissue xenografting and that the mice do not need to be castrated for optimal results.