bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and characterization of PNIPAM‐b‐(PEA‐g‐PDEA) double hydrophilic graft copolymer
Authors: Feng Chun , Shen Zhong , Gu Lina , Zhang Sen , Li Litao , Lu Guolin , Huang Xiaoyu
Published: July 2008

A series of well‐defined double hydrophilic graft copolymers, consisting of poly(N‐isopropylacrylamide)‐b‐poly(ethyl acrylate) (PNIPAM‐b‐PEA) backbone and poly(2‐(diethylamino)ethyl methacrylate) (PDEA) side chains, were synthesized by successive atom transfer radical polymerization (ATRP). The backbone was firstly prepared by sequential ATRP of N‐isopropylacrylamide and 2‐hydroxyethyl acrylate at 25 °C using CuCl/tris(2‐(dimethylamino)ethyl)amine as catalytic system. The obtained diblock copolymer was transformed into macroinitiator by reacting with 2‐chloropropionyl chloride. Next, grafting‐from strategy was employed for the synthesis of poly(N‐isopropylacrylamide)‐b‐[poly(ethyl acrylate)‐g‐poly(2‐(diethylamino)ethyl methacrylate)] (PNIPAM‐b‐(PEA‐g‐PDEA)) double hydrophilic graft copolymer. ATRP of 2‐(diethylamino)ethyl methacrylate was initiated by the macroinitiator at 40 °C using CuCl/hexamethyldiethylenetriamine as catalytic system. The molecular weight distributions of double hydrophilic graft copolymers kept narrow. Thermo‐ and pH‐responsive micellization behaviors were investigated by fluorescence spectroscopy, 1H NMR, dynamic light scattering, and transmission electron microscopy. Unimolecular micelles with PNIPAM‐core formed in acidic environment (pH = 2) with elevated temperature (≥32 °C); whereas, the aggregates turned into vesicles in basic surroundings (pH ≥ 7.2) at room temperature. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5638–5651, 2008
Structural characterization of radiation‐grafted block copolymer films, using SANS technique
Authors: Mortensen Kell , Gasser Urs , Gürsel Selmiye Alkan , Scherer Günther G.
Published: July 2008

We report small‐angle neutron scattering studies of grafted copolymer films of perfluorinated poly(ethylene propylene), FEP, base polymer and polystyrene, PS, grafted blocks. The films show highly anisotropic scattering patterns, revealing nematic‐like ordering of the crystalline domain structure as a consequence of the processing conditions. Upon grafting, the styrene swells the amorphous domains in the copolymer formation. For styrene content beyond roughly 15%, the amorphous regimes increase on the cost of crystalline domains. To stabilize the rather well‐defined domain structure already given by the original FEP base material, the samples need to be cross‐linked. Without cross‐linking, the nanometer length scale domains vanish, and some large scale structure takes over, likely driven by the immiscibility between FEP and PS. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1660–1668, 2008
Pore‐filling electrolyte membranes based on microporous polyethylene matrices activated with plasma and sulfonated hydrogenated styrene butadiene block copolymer. Synthesis, microstructural and electrical characterization
Authors: Navarro Amparo , del Río Carmen , Acosta José Luis
Published: July 2008

In this research a series of pore‐filling electrolyte membranes were prepared, based on a sulfonated and hydrogenated styrene/butadiene block copolymer (SHSBS) and plasma‐treated microporous polyethylene (PE) membranes. The pore‐filling electrolyte membranes were characterized by means of scanning electronic microscopy (SEM), infrared spectroscopy (FTIR‐ATR), and dynamic mechanical analysis (DMA). In addition, the water uptake and methanol/water uptake capacities of these membranes were determined using several methanol in water solutions, as well as the permeability coefficients, for both water and methanol, using a 2 M methanol in water solution and pure methanol. Finally, electrical behavior was recorded by means of electrochemical impedance spectroscopy (EIS) and the four probe technique (FPT). The SEM images recorded show good coating of the pore‐filling electrolyte membranes on the plasma‐treated PE matrices, and DMA shows the proper relaxations of the two components: PE and SHSBS. Furthermore, the methanol/water absorption capacity was observed to diminish with plasma treatment of the matrix. Methanol permeability of the pore‐filling electrolyte membranes is notably lower than that of the Nafion® membrane, ion conductivity moving in the order of 10−2 S cm−1. Both of these characteristics qualify the experimental membranes as candidates to be applied as proton exchangers in fuel cells (FCs). © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1684–1695, 2008
3D diamond‐containing nanocomposites based on hybrid polyurethane–poly(2‐hydroxyethyl methacrylate) semi‐IPNs: Composition‐nanostructure‐segmental dynamics‐elastic properties relationships
Authors: Karabanova L. V. , Bershtein V. A. , Sukhanova T. E. , Yakushev P. N. , Egorova L. M. , Lutsyk E. D. , Svyatyna A. V. , Vylegzhanina M. E.
Published: July 2008

Nanostructure, glass transition dynamics and elastic properties were studied in the 3D nanodiamond‐containing composites based on polyurethane‐poly(2‐hydroxyethyl methacrylate) semi‐interpenetrating polymer networks (PU‐PHEMA semi‐IPNs), neat PU or PHEMA matrices. Nanodiamond (ND) content in the nanocomposites varied from 0.25 to 3 wt %. Combined differential scanning calorimetry/ laser‐interferometric creep rate spectroscopy/atomic force microscopy approach was utilized. A large impact of small 3D ND additives on PU‐PHEMA networks' dynamics and properties was revealed under conditions when an average inter‐particle distance L exceeds by far gyration radius Rg. The pronounced heterogeneity of glass transitions' dynamics and two opposite effects were observed. The main effect was a strong suppression of PHEMA glass transition dynamics at 90–180 °C, with the enhancement of creep resistance and threefold to sixfold increasing modulus of elasticity. The peculiarly crosslinked structure of nanocomposites, due to double covalent hybridization, resulted in low rheological percolation threshold, and a synergistic effect in dynamics was observed. Less pronounced effect of accelerating dynamics in the temperature region between β‐ and α‐transitions in PHEMA was associated with dynamics in domains with loosened molecular packing. The distinct physical limit for “anomalous” decreasing Tg is predicted in terms of the notion of the common segmental nature of α‐ and β‐relaxations. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1696–1712, 2008
Thermo‐ and pH‐induced phase transitions and network parameters of poly(N‐isopropylacrylamide‐ co‐2‐acrylamido‐2‐methyl‐propanosulfonic acid) hydrogels
Authors: Turan Eylem , Demirci Serkan , Caykara Tuncer
Published: July 2008

Dual temperature‐ and pH‐sensitive hydrogels composed of N‐isopropylacrylamide (NIPAM) and 2‐acrylamido‐2‐methyl‐propanosulfonic acid (AMPS) were prepared by free‐radical crosslinking copolymerization in aqueous solution at 22 °C. The mole percent of AMPS in the comonomer feed was varied between 0.0 and 7.5, while the crosslinker ratio was fixed at 5.0/100. The effect of AMPS content on thermo‐ and pH‐ induced phase transitions as well as equilibrium swelling/deswelling, interior morphology and network structure was investigated. The volume phase transition temperature (VPT‐T) was determined by both swelling/deswelling measurements and differential scanning calorimetry (DSC) technique. In addition, the volume phase transition pH (VPT‐pH) was detected from the derivative of the curves of the swelling ratio (dQv/dpH) versus pH. The polymer‐solvent interaction parameter (χ) and the average molecular mass between crosslinks ($\overline M_{\rm c}$) of hydrogels were calculated from swelling ratios in buffer solutions at various pHs. The enthalpy (ΔH) and entropy (ΔS) changes appearing in the χ parameter of hydrogels were also determined by using the modified Flory–Rehner equation. The negative values for ΔH and ΔS indicated that the hydrogels had a negative temperature‐sensitive property in water, that is, swelling at a lower temperature and shrinking at a higher temperature. It was observed that the experimental swelling data of hydrogels at different temperature agreed with the modified Flory‐Rehner approach based on the affine network model. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1713–1724, 2008
Crystallization behavior and morphological development of isotactic polypropylene with an aryl amide derivative as β‐form nucleating agent
Authors: Dong Mu , Guo Zhaoxia , Yu Jian , Su Zhiqiang
Published: July 2008

This article reports crystallization behaviors of isotactic polypropylene (iPP) with an aryl amide derivative (TMB‐5) as β‐form nucleating agent. The effects of nucleating agent concentration, thermal history and assemble morphology of nucleating agent on the crystallization behaviors of iPP were studied by differential scanning calorimetry, X‐ray diffraction, and polarized optical microscopy. The results indicated that the TMB‐5 concentration should surpass a threshold value to get products rich in β‐iPP. The diverse morphologies of TMB‐5 are determined by nucleating agent concentration and crystallization condition. At higher concentrations, the recrystallized TMB‐5 aggregates into needle‐like structure, which induces mixed polymorphic phases on the lateral surface and large amount of β modification around the tip. High β nucleation efficiency was obtained at the lowest studied crystallization temperature, which is desirable for real molding process. TMB‐5 prefers to recrystallize from the melt at higher concentration and lower crystallization temperature. The difference in solubility, pertinent to concentration and crystallization temperature, determined the distinct crystallization behaviors of iPP. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1725–1733, 2008
Influence of α‐ZrP fillers and process conditions on the morphology and the gas barrier properties of filled polyamide 6 films
Authors: Olivier L. , Sabard M. , Fulchiron R. , Espuche E. , David L. , Guiu A.
Published: July 2008

Composite films based on polyamide 6 and lamellar unmodified α‐ZrP nanofillers have been prepared for low filler amounts (less than 2 wt %) using cast process or blowing process. Whatever be the filler content and the film process conditions, the lamellar nanofillers were not intercalated by the polymer chains and microcomposites were obtained. On the other hand, the matrix crystalline structure highly depended on the presence of fillers and on the film process conditions. The nature of the crystalline phase and its orientation were shown to play a major role on the film barrier properties to helium. For instance, the presence of γ crystalline phase associated to a specific orientation of the crystalline lamellae parallel to the film surface could significantly contribute to enhance barrier properties. This specific morphology was favored by the presence of α‐ZrP in the formulation but depended also on the process conditions. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1734–1746, 2008
Fabrication and characteristics of SiOx ‐core nanowires: Comparison study between uncoated and ZnO‐coated SiOx nanowires
Authors: Kim Hyoun Woo , Shim Seung Hyun , Kong Myung Ho , Yang Hack‐Hui
Published: July 2008

We have demonstrated an approach to the synthesis of SiOx ‐core nanowires, on which ZnO shell layer would be subsequently deposited. We have discussed the possible growth mechanism of SiOx nanowires, in regard to the role of Au catalyst. For a comparison study between uncoated and coated nanowires, samples were characterized by X‐ray dif‐ fraction (XRD), transmission electron microscopy (TEM), and photoluminescence spectroscopy (PL). This method can be applied to a wide range of materials and results in various heterostructures, which may serve as potential building blocks in various nanodevices. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Amorphous Sn–Ga–Zn–O channel thin‐film transistors
Authors: Ogo Youichi , Nomura Kenji , Yanagi Hiroshi , Kamiya Toshio , Hirano Masahiro , Hosono Hideo
Published: July 2008

Transparent amorphous oxide semiconductors (TAOS) such as a‐InGaZnO4 are expected to be applied for channels of low‐temperature high‐mobility thin‐film transistors (TFTs). This paper presents the fabrication and characteristics of amorphous Sn–Ga–Zn–O (a‐SGZO) channel TFTs. Bottom‐gate TFTs were fabricated using as‐deposited and annealed a‐SGZO channels on a‐SiO2/n+‐Si wafers. Contrary to a‐InGaZnO4 channel TFTs, the device performances of the as‐deposited channel TFTs were very poor, e.g., on‐currents (Ion) were <10–7 A and on/off current ratios (Ron/off) were <101. The TFTs using channels annealed at 500 °C showed good performances such as Ion > 10–5 A, Ron/off > 106 and μsat ∼ 1.8 cm2 V–1 s–1. Optical measurements indicate that the improvement is accompanied by a reduction of the density of subgap states. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The role of source and drain material in the performance of GIZO based thin‐film transistors
Authors: Barquinha P. , Vilà A. , Gonçalves G. , Pereira L. , Martins R. , Morante J. , Fortunato E.
Published: July 2008

Indium tin oxide (ITO) has been used as the prefered electrode material for the emerging area of transparent electronics, namely for thin‐film transistors (TFTs) based on oxide semiconductors. This work pretends to investigate different materials to replace ITO in inverted‐staggered TFTs based on gallium–indium–zinc oxide (GIZO), one of the most promissing oxide semiconductors for TFTs. The analyzed electrode materials are indium–zinc oxide (IZO), Ti, Mo and Ti/Au. Devices are analyzed with special focus on the contact resistance fundamentals, including the extraction of source/ drain series resistances and TFTs intrinsic parameters, such as intrinsic mobility (µi) and intrinsic threshold voltage (VTi). The obtained contact resistance values are between 10 kΩ and 20 kΩ, and the best devices have field effect mobility (µFE) close to 25 cm2/V s and on/off ratio close to 108. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Robustness properties of Cuscore statistics for monitoring a nonstationary system
Authors: Valverde‐Ventura René , Nembhard Harriet Black
Published: July 2008

We investigate the performance of cumulative score (Cuscore) charts in monitoring a nonstationary process subject to minimum mean‐squared error (MMSE) feedback control. Specifically, we have previously designed Cuscore statistics to discover spike or step signals hidden in a nonstationary noise disturbance for feedback‐controlled processes. Here, we study the properties of the proposed policies in terms of their robustness to process model misspecification, to deviations from assumed values for their parameters, to model misspecification for the disturbance as well as to model misspecification for the signal. We found that, in general, the Cuscore charts are fairly robust to process and signal model misspecification. However, they are less robust to departures from its true parameter values. We present a numerical example to demonstrate the importance of understanding the Cuscore's robustness as well as its construction and application. Copyright © 2008 John Wiley & Sons, Ltd.
Rehabilitation nurses' experiences providing spiritual care
Authors: Gebhardt Mary Catherine
Published: July 2008

The purpose of this phenomenological study was to examine rehabilitation nurses' experiences providing spiritual care. Rehabilitation nurses provide care for patients and their families after life‐threatening events and are in a unique position to meet holistic health care needs. Little is written about rehabilitation nurses' perceptions of providing spiritual care. Fourteen rehabilitation nurses self‐identified as providing spiritual care and agreed to participate in individual interviews. The interviews focused on the nurses' definition of spiritual care, interventions the nurses perceived as spiritual and their comfort in providing spiritual care. More studies are needed to determine if providing spiritual care improves patient outcomes. Copyright © 2008 John Wiley & Sons, Ltd.
Psychological Profile and Work Status of a Predominantly Hispanic Worker's Compensation Population With Chronic Limb Pain
Authors: Monsivais Jose J. , Robinson Kris
Published: July 2008

The purposes of this study were to describe the psychosocial profile and to measure function (posttreatment work status) after surgical and non-surgical treatment in a predominantly Hispanic worker's compensation population with chronic limb pain. We conducted an archival review of records from 91 patients treated for neuropathic pain in a specialty clinic over a 10-year period who had extreme difficulty accepting or managing pain. Medical records from individuals with proven nerve dysfunction experiencing pain >3 months and whose record contained a full psychological evaluation were included. All patients received patient-centered care, a prescription to return to work, periodic pain assessment, and clinical evaluation of sensory and motor function plus pharmacologic pain management. Surgery was determined by the degree of sensory-motor abnormalities in the absence of untreated psychological distress regardless of pain level or worker's compensation status. The majority of patients returned to work after treatment of nerve injury. No differences were noted between surgical/non-surgical treatment groups on initial pain level ( p=0.2), litigation status ( p> 0.5), and posttreatment work status ( p>0.05). However, individuals expecting surgery also expected total relief of pain with surgical intervention. Psychosocial assessment, support, and adequate pain treatment seem to mediate the ability of an individual with chronic limb pain to return to work regardless of surgical/non-surgical treatment. Patients' expectations of surgery may be unrealistic and are best addressed prior to treatment.
Protein tyrosine phosphatase receptor‐type O (PTPRO) is co‐regulated by E2F1 and miR‐17‐92
Authors: Xu Xin , Hong Yan , Kong Chenfei , Xu Liang , Tan Jiang , Liang Qian , Huang Baiqu , Lu Jun
Published: July 2008

PTPRO is often silenced by DNA hypermethylation in primary human tumors and cancer cell lines and functions as a tumor suppressor. Here we show that PTPRO is a target of E2F1. In addition, the microRNA cluster miR‐17‐92, another target of E2F1, participates in PTPRO regulation. PTPRO mRNA was up‐regulated during S phase in synchronized HeLa cells and in vitro PTPRO promoter activity is high in early S phase while the PTPRO 3′UTR reporter activity is low in late S phase. This study provides evidence that the PTPRO gene is co‐regulated by both E2F1 and miR‐17‐92.
Adenocarcinoma of the disseminated prostate in a cat
Authors: Tursi Massimiliano , Costa Tiziana , Valenza Federico , Aresu Luca
Published: July 2008

An adenocarcinoma of the disseminated prostate gland with pulmonary, myocardial and renal metastases is described in a 12-year-old, neutered male European cat. Histologically, the tumour was localised in the spongy layer of the prostatic urethra and showed an epithelial alveolar pattern. Considering the anatomic, microscopic and immunohistochemical findings, the tumour was diagnosed as an adenocarcinoma of the disseminated prostate gland. To our knowledge this is the first report of adenocarcinoma of the disseminated prostate gland in a cat.
Prevalence of influenza A H5N1 virus in cats from areas with occurrence of highly pathogenic avian influenza in birds
Authors: Marschall Julia , Schulz Bianka , Priv-Doz Timm C. Harder , Priv-Doz Thomas W. Vahlenkamp , Huebner Janine , Huisinga Elke , Hartmann Katrin
Published: July 2008

Natural and experimental infections have shown that cats are susceptible to highly pathogenic avian influenza A virus subtype H5N1 (HPAIV H5N1). Cats can be severely affected and die from the disease, but subclinical infections have also been reported. To learn more about the role of cats in the spread of the virus and about the risk posed to cats, the prevalence of H5N1 virus was examined in 171 cats from areas in Germany and Austria in which birds infected with HPAIV H5N1 had been found. Pharyngeal swabs were examined for H5N1 virus using real-time polymerase chain reaction, and serum samples were tested for antibodies to influenza virus. None of the cats showed evidence of infection with H5N1 virus. Prevalence of H5N1 virus was determined to be <1.8% (95% confidence interval (CI): 0.000000–0.017366); prevalence of antibodies was <2.6% (95% CI: 0.000000–0.025068).
A method for estimation of urea using ammonia electrode and its applicability to milk samples
Authors: Sharma Rajan , Rajput Yudhishthir S , Kaur Sumandeep , Tomar Sudhir K
Published: July 2008

A method for the estimation of urea in milk using ammonia electrode is described. Urea is first degraded by urease enzyme into ammonium ion and carbon dioxide at neutral pH. The ammonium ion is then converted into ammonia at alkaline pH. A linear inverse relationship was observed between logarithmic concentration of ammonia or urea and electrode response. Repeatability, expressed as a coefficient of variation, was 1·77% at a level of 8·92 mm-urea in milk. The method was validated in milk samples spiked with between 2×10−3and 10×10−3 m-urea and recovery of added urea was quantitative. Whereas, preservative sodium azide at 0·5 g/l or 2 g/l level did not affect results, lower values of urea concentration in presence of Bronopol at 0·5 g/l were observed. Urea levels in milk samples estimated by this method were comparable to standard enzymatic method. The method is simple, fast and is not prone to interference from other milk constituents.
VISUAL INPUT ENHANCEMENT AND GRAMMAR LEARNING: A Meta-Analytic Review
Authors: Lee Sang-Ki , Huang Hung-Tzu
Published: July 2008

Effects of pedagogical interventions with visual input enhancement on grammar learning have been investigated by a number of researchers during the past decade and a half. The present review delineates this research domain via a systematic synthesis of 16 primary studies (comprising 20 unique study samples) retrieved through an exhaustive literature search. The overall magnitude of visual input enhancement was addressed by calculating and aggregating effect sizedvalues. The results indicate that second language readers provided with enhancement-embedded texts barely outperformed those who were exposed to unenhanced texts with the same target forms flooded in them (d= 0.22). A theoretical tension between form and meaning was indicated by a small but negative effect size value for learners' meaning processing (d= −0.26). The importance of improving methodological practices in this research domain, including the reporting of statistical and treatment-related information and the counteracting of a possible publication bias, was also revealed by the synthetic analyses and is further discussed.
TASK TYPE AND REACTIVITY OF VERBAL REPORTS IN SLA: A First Look at a L2 Task Other Than Reading
Authors: Bowles Melissa A.
Published: July 2008

Despite the frequency with which verbal reports are used in SLA to gather data on learners' cognitive processes (e.g., Bowles, 2003, 2004; Mackey, Gass, & McDonough, 2000; Rosa & Leow, 2004a, 2004b), only two studies (Bowles & Leow, 2005; Leow & Morgan-Short, 2004) have investigated verbal reports' reactivity (i.e., whether they alter cognitive processes) during second language (L2) reading. This is the first study to investigate the reactivity of verbal reports on a L2 problem-solving task. First-semester learners of Spanish were assigned to one of six experimental conditions, which differed in terms of the type of verbalization (i.e., metalinguistic, nonmetalinguistic, or silent) and the type of feedback (i.e., implicit vs. explicit). Results show that metalinguistic verbalization significantly increased time on task and also hindered participants' ability to produce exemplars of the target structure seen during the experimental task. However, neither type of verbalization significantly affected participants' ability to produce novel exemplars of the target structure, and there was no interaction between verbalization and feedback.
Weak solvability of a piezoelectric contact problem
Authors: MIGÓRSKI STANISŁAW , OCHAL ANNA , SOFONEA MIRCEA
Published: July 2008

We consider a mathematical model which describes the frictional contact between a piezoelectric body and a foundation. The material behaviour is modelled with a non-linear electro-elastic constitutive law, the contact is bilateral, the process is static and the foundation is assumed to be electrically conductive. Both the friction law and the electrical conductivity condition on the contact surface are described with subdifferential boundary conditions. We derive a variational formulation of the problem which is of the form of a system of two coupled hemi-variational inequalities for the displacement and the electric potential fields, respectively. Then we prove the existence of a weak solution to the model and, under additional assumptions, its uniqueness. The proof is based on an abstract result on operator inclusions in Banach spaces.
Flattened current sheet and its evolution in substorms
Authors: Shen C. , Liu Z. X. , Li X. , Dunlop M. , Lucek E. , Rong Z. J. , Chen Z. Q. , Escoubet C. P. , Malova H. V. , Lui A. T. Y. , Fazakerley A. , Walsh A. P. , Mouikis C.
Published: July 2008

In this research, the properties of a tail current sheet, which has a flattened geometry, and its evolution during substorm activity have been investigated. The geometrical configuration of the magnetic field and the spatial distribution of the current density in a flattened current sheet have been revealed with certainty for the first time. It is found that such a flattened current sheet has sufficiently strong By (GSM) within its neutral sheet that the magnetic field lines (MFLs) in the neutral sheet are lie almost in the GSM equatorial plane and that the normal directions are generally northward. Detailed analyses show that, the magnetic field lines are spiral‐like, not plane curves, which are left‐handed or right‐handed spirals for By > 0 or By < 0. This magnetic rotation occurs predominantly in the neutral sheet. The flattened current sheet may be very thin, and the thickness of the neutral sheet is much less than the minimum radius of the curvature of the MFLs in the current sheet. The analysis also suggests that the neutral sheet current is field‐aligned and lies mainly duskward. The curvature current makes little contribution to the total current in the flattened current sheet. The main current carriers in the neutral sheet of the flattened current sheet are electrons. A statistical survey shows that there is one positive correlation between By in the flattened current sheet and IMF By and penetration efficiency is 0.67. Flattened current sheets may occur in both quiet and disturbed periods and may appear at all phases of the substorms. During the growth phase of a substorm event, the neutral sheet of the flattened current sheet is shown to become progressively thinner, while the associated current density is increasing gradually. It is found that the northern turning of the IMF has triggered the explosive growth phase at the end of the growth phase, which lasts several minutes. At the explosive growth phase, the flattened current sheet becomes much thinner and the current density in the neutral sheet then increases considerably and reaches a value larger than 0.017 μAm−2. Just after the onset of the substorm, the current density in the neutral sheet drops abruptly and varies turbulently.
A study of the relationship between stratospheric gravity waves and polar mesospheric clouds at Davis Antarctica
Authors: Innis J. L. , Klekociuk A. R. , Morris R. J. , Cunningham A. P. , Graham A. D. , Murphy D. J.
Published: July 2008

We used a Rayleigh lidar located at Davis station, East Antarctica, to compare Polar Mesospheric Cloud (PMC) and stratospheric gravity wave (GW) strengths in the austral summer 2005–2006. Earlier similar studies from Greenland noted that intervals of large stratospheric GW activity appeared to coincide with reduced PMC strengths. We measure the stratospheric GW strength in the 30–45 km altitude range, for waves of vertical wavelength between ∼2 and ∼10 km, and of periods greater than 1 h. We find little consistency with the Greenland studies, as the occurrence of PMC over Davis appear to have little relationship to observed stratospheric gravity wave activity. Hemispheric differences, in both PMC strength and occurrence and in gravity wave strength, may have a role in explaining our results. Our data suggest that a significant controller of occurrence of PMC over Davis is related to diurnal tidal movement. We also investigate the potential influence of sampling biases in our data set.
Seasonal variation of short‐period (<2 h) gravity wave activity over Gadanki, India (13.5°N, 79.2°E)
Authors: Dutta Gopa , Tsuda Toshitaka , Kumar P. Vinay , Kumar M. C. Ajay , Alexander Simon P. , Kozu Toshiaki
Published: July 2008

We have analyzed the seasonal variation of short‐period (<2 h) gravity wave activity in the troposphere and lower stratosphere using the wind observations made with VHF radar at Gadanki (13.5°N, 79.2°E), India. Four years of high resolution (∼3 min) wind data (2003–2006) have been used to study variance and momentum flux of short‐period gravity waves. Both horizontal and vertical variances show annual variation. Variances in the upper troposphere (12–16 km) and lower stratosphere (18–21 km) are found to maximize in the wet months of June–July–August coinciding with the peaks of outgoing longwave radiation (OLR) and the rain rate (surface and Tropical Rainfall Measuring Mission [TRMM] 2 km rainfall). An additional strong peak of variance is observed in the height ranges of 4–12 km during spring which corresponds to TRMM storm height maximum. The measurements suggest deep convective activity to be the main source of short period gravity waves. Variances in the UTLS region are found to correlate well with square of wind shear indicating possible in situ generation of the gravity waves. Topographic generation of short period gravity waves does not seem to be important for this site. An interannual variability is observed in the measured wave activity. Zonal momentum flux shows annual variation with westward preference in the wet season whereas the meridional flux does not indicate any clear variation.
Year‐round record of size‐segregated aerosol composition in central Antarctica (Concordia station): Implications for the degree of fractionation of sea‐salt particles
Authors: Jourdain Bruno , Preunkert Susanne , Cerri Omar , Castebrunet Hélène , Udisti Roberto , Legrand Michel
Published: July 2008

The origin of sea‐salt aerosol that reaches the high Antarctic plateau and is trapped in snow and ice cores remains still unclear. In particular, the respective role of emissions from the open ocean versus those from the sea‐ice surface is not yet quantified. To progress on this question, the composition of bulk and size‐segregated aerosol was studied in 2006 at the Concordia station (75°S, 123°E) located on the high Antarctic plateau. A depletion of sulfate relative to sodium with respect to the seawater composition is observed on sea‐salt aerosol reaching Concordia from April to September. That suggests that in winter, when the sea‐salt atmospheric load reaches a maximum, emissions from the sea‐ice surface significantly contribute to the sea‐salt budget of inland Antarctica.
Crustal‐scale structural architecture, shortening, and exhumation of an active, eroding orogenic wedge (Chugach/St Elias Range, southern Alaska)
Authors: Meigs Andrew , Johnston Sarah , Garver John , Spotila James
Published: July 2008

Active mountain building associated with the accretion of the Yakutat microplate (YT) in southern Alaska is characterized through the combination of a new balanced cross section and new low‐temperature cooling ages. This analysis constrains the amount and timing of shortening, the spatial and temporal trends of exhumation, and the interplay between structural development and exhumation. A fold‐and‐thrust belt comprising three principal thrust sheets (the Hope Creek, Sullivan, and an offshore thrust sheet from north to south) characterizes the YT internal structure, which has absorbed a minimum of ∼82 km shortening. Assuming shortening and foreland basin development occurred contemporaneously, the shortening rate across the YT is ∼13–14 mm/a after 5.6 Ma. Detrital apatite fission track ages, from south to north, are unreset along the southern edge of the Sullivan thrust sheet at the coast, are reset and have ages younger than 6.3 Ma within the thrust belt, and have reset cooling ages of ∼13 Ma in the North American upper plate. Only the zircon samples from the northern, internal YT are potentially reset. Exhumation rates within the thrust belt vary from 0.3 ± 0.1 mm/a to 4 ± 1.8 mm/a. Combining the thermochronometric and structural data indicate that wedge exhumation since ∼6 Ma is 500 km2 and that particle trajectories have larger horizontal than vertical components. Whereas exhumation and shortening have been focused on the windward side of the Chugach/St. Elias Range since ∼6 Ma, the cooling ages do not uniquely distinguish between orographically versus tectonically controlled erosion.
Ionospheric localisation and expansion of long‐period Pi1 pulsations at substorm onset
Authors: Milling David K. , Rae I. Jonathan , Mann Ian R. , Murphy Kyle R. , Kale Andy , Russell Christopher T. , Angelopoulos Vassilis , Mende Stephen
Published: July 2008

We examine the initial ionospheric localisation and expansion of Pi1 pulsations associated with a substorm onset observed on 1st November 2006 with the combined CARISMA and THEMIS GMAG network of ground‐based magnetometers. We demonstrate how the first ionospheric pulsation disturbance lies in the long‐period Pi1 band. The long‐period Pi1 pulsations at substorm onset are initially localised in longitude, and expands away from an epicentre in the ionosphere, with ∼16 s timing between stations. We further establish a link between the location of the downward field‐aligned current (FAC) element which subsequently develops within the substorm current wedge (SCW), and the initial location of the onset of long‐period Pi1 pulsations. The arrival of the initial long‐period Pi1 wavepacket demonstrates the importance of global networks of ground‐based magnetometers for probing substorm onset. The Pi1 expansion proceeds westward at a rate of approximately 1 MLT hour per ∼20 seconds, representing a very rapid expansion of the Pi1 signal at the ground. The resolution of the Pi1 localisation and the rate of expansion suggest Pi1 waves can play an important role in studies of the causal sequence of energy release in substorms.
Temperature trends at high elevations: Patterns across the globe
Authors: Pepin N. C. , Lundquist J. D.
Published: July 2008

Most climate models suggest amplification of global warming in high mountains, but observations are less clear. Using comprehensive, homogeneity‐adjusted temperature records from over 1000 high elevation stations across the globe, we examine the causes of changing temperature trends with elevation, assessing the roles of free atmospheric change, topography (exposure and aspect), and cryospheric feedback. The data show that observed 20th century temperature trends are most rapid near the annual 0°C isotherm due to snow‐ice feedback. Mountain summit and freely draining slope sites are dominated by free‐air advection and thus have consistent trend magnitudes, with reduced inter‐site variance in comparison with incised valley sites where local factors are more important. Thus, while there has been no simplistic elevational increase in warming rates, some generalizations can be made. Water resources and ecosystems near the 0°C isotherm in the extratropics are at increased risk from accelerated warming. The data also suggest that exposed mountain summits, away from the effects of urbanization and topographic sheltering, may provide a relatively unbiased record of the planet's climate.
Spatial variability of carbon monoxide in Venus' mesosphere from Venus Express/Visible and Infrared Thermal Imaging Spectrometer measurements
Authors: Irwin P. G. J. , de Kok R. , Negrão A. , Tsang C. C. C. , Wilson C. F. , Drossart P. , Piccioni G. , Grassi D. , Taylor F. W.
Published: July 2008

Observations of Venus' mesosphere by the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS)‐M instrument of Venus Express have been used to investigate the spatial distribution of CO above Venus' nightside cloud tops by fitting the CO absorption in the (1–0) CO band around 4.7 μm. We find little spatial variation in the abundance of CO at midlatitudes, with a retrieved abundance of approximately 40 ± 10 ppm just above the cloud tops between 65 and 70 km altitude. Unfortunately, we find it very difficult to constrain the abundance of CO in the cold polar collar, centered at about 70°S, as the retrieved temperature structure in the CO line‐forming region masks the absorption lines. However, there is a possibility that CO increases toward the poles, as we detect a significant signature of high levels of CO over Venus' south polar dipole feature in all the observations analyzed so far. To constrain the abundance of CO more closely will require the analysis of higher‐resolution VIRTIS‐H observations. In addition, limb observations would greatly help to resolve any possible temperature/cloud ambiguities and allow us to assess vertical variations in the abundance of CO.
Genomic Profiles of Damage and Protection in Human Intracerebral Hemorrhage
Authors: Carmichael S Thomas , Vespa Paul M , Saver Jeffery L , Coppola Giovanni , Geschwind Daniel H , Starkman Sidney , Miller Chad M , Kidwell Chelsea S , Liebeskind David S , Martin Neil A
Published: July 2008

Intracerebral hemorrhage (ICH) produces a high rate of death and disability. The molecular mechanisms of damage in perihematomal tissue in humans have not been systematically characterized. This study determines the gene expression profile and molecular networks that are induced in human perihematomal tissue through molecular analysis of tissue obtained from endoscopic clot evacuation. Differentially expressed genes and their cellular origin were confirmed in a mouse model of ICH. A total of 624 genes showed altered regulation in human ICH. Bioinformatic analysis shows that these genes form interconnected networks of proinflammatory, anti-inflammatory, and neuronal signaling cascades. Intracerebral hemorrhage evokes coordinated upregulation of proinflammatory signaling through specific cytokines and chemokines and their downstream molecular pathways. Anti-inflammatory networks are also induced by ICH, including annexins A1 and A2 and transforming growth factor beta (TGF β) and their intracellular cascades. Intracerebral hemorrhage downregulates many neuronal signaling systems, including the N-methyl-D-aspartic acid (NMDA) receptor complex and membrane ion channels. Select portions of these molecular networks were confirmed in the mouse, and the proteins in a subset of these networks localized to subsets of neurons, oligodendrocytes, or leukocytes. These inflammatory and anti-inflammatory networks interact at several key points in neutrophil signaling, apoptotic cell death, and protease responses, and indicate that secondary damage in ICH activates opposing molecular systems.
A Comprehensive Analysis of Gait Impairment after Experimental Stroke and the Therapeutic Effect of Environmental Enrichment in Rats
Authors: Wang Yonggang , Bontempi Bruno , Hong Shwehuey M , Mehta Kala , Weinstein Philip R , Abrams Gary M , Liu Jialing
Published: July 2008

Although gait changes are considered as reliable indices of stroke severity and efficacy of rehabilitative therapies in humans, data from animal models of focal ischemia are lacking. To determine the effect of stroke on gait function in adult rats with distal middle cerebral artery occlusion (MCAO), we assessed the longitudinal changes in gait using an automated computer-assisted gait analysis system. Four days after MCAO, intensity, maximal area of contact, and paw angle were significantly decreased in the affected forepaw whereas the double support time using ipsilateral paws increased. Relative print positions between the fore and hindpaws and limb coupling were also altered, suggesting that stroke affected sensorimotor status and reduced limb coordination. Except for paw angle, these impairments persisted for at least 5 weeks. However, unlike human stroke patients, stride length and stance were not affected in rats with MCAO. Environmental enrichment for 4 weeks improved paw contact area and relative print position of the affected limb and reduced double support time in ischemic rats compared with controls. Our results indicate that gait analysis provides great insight into various aspects of motor function changes in ischemic quadrupeds, and that environmental enrichment is beneficial in reducing a variety of poststroke gait impairments possibly through enhanced structural plasticity mechanisms within injured cortical neuronal networks underlying locomotor function.
Physical Activity Patterns During Weight Maintenance Following a Low‐energy Density Dietary Intervention
Authors: Cox Tiffany L. , Malpede Christie Z. , Desmond Renee A. , Faulk Lori E. , Myer Rory A. , Henson C. Suzanne , Heimburger Douglas C. , Ard Jamy D.
Published: July 2008

Objective: The objective was to determine the role of physical activity (PA) and energy intake on weight maintenance among former University of Alabama at Birmingham EatRight Weight Management Program participants.

Research Methods and Procedures: Eighty‐nine former participants completed follow‐up visits ≥1 year after completing EatRight. BMI was calculated using measured height and weight. Diet intake was estimated from 4‐day food records. PA was assessed using a module from the Behavioral Risk Factor Surveillance System Survey. Cut‐off points were chosen based on the distribution of minutes of activity. For moderate and total activity, cut‐off points were 0, 1 to 30, 31 to 60, and >60 minutes. For vigorous activity, the categories were 0, 1 to 20, 21 to 30, and >30 minutes. General linear models determined the association of PA with change in weight at follow‐up controlling for gender and total energy intake (kcal/d).

Results: At follow‐up, 80% (n = 71) of participants maintained (regained <5% of program end weight) their body weight and 20% had gained weight. Mean weight change was 1.0 ± 6.5 kg. Maintainers consumed 384 fewer kcal/d on average. Maintainers had a lower energy density dietary pattern (1.58 vs. 2.01 kcal/g, p < 0.01). There was no significant difference in PA min/d reported by maintainers and gainers.

Discussion: Our results suggest that, despite being minimally active, weight‐reduced individuals can successfully maintain their newly achieved body weight with appropriate caloric intake. Adopting a lower calorie, low energy density dietary pattern may reduce the amount of PA that is truly necessary for weight maintenance.
Association of Cigarettes Smoked Daily with Obesity in a General Adult Population
Authors: Chiolero Arnaud , Jacot‐Sadowski Isabelle , Faeh David , Paccaud Fred , Cornuz Jacques
Published: July 2008

Objective: We analyzed the cross‐sectional association between obesity and smoking habits, taking into account diet, physical activity, and educational level.

Research Methods and Procedures: We used data from the 2002 Swiss Health Survey, a population‐based cross‐sectional telephone survey assessing health and self‐reported health behaviors. Reported smoking habits, height, and weight were available for 17,562 subjects (7844 men and 9718 women) ≥25 years of age. BMI was calculated as (self‐reported) weight divided by height2.

Results: Mean BMI was 25.1 kg/m2 for non‐smokers, 26.1 kg/m2 for ex‐smokers, 24.6 kg/m2 for light smokers (1 to 9 cigarettes/d), 24.8 kg/m2 for moderate smokers (10 to 19 cigarettes/d), and 25.3 kg/m2 for heavy smokers (≥20 cigarettes/d) in men and 24.0, 24.1, 22.9, 22.9, and 23.3 kg/m2, respectively, in women. Obesity (BMI ≥ 30 kg/m2) was increasingly frequent with older age, lower physical activity, lower fruits/vegetables intake, and lower educational level. Compared with non‐smokers, the odds ratio for obesity vs. normal weight (BMI = 18.5 to 25.0 kg/m2) adjusted for age, nationality, educational level, leisure time physical activity, and fruit/vegetable intake were 1.9 (95% confidence interval: 1.5 to 2.3) for ex‐smokers, 0.5 (0.3 to 0.8) for light smokers, 0.7 (0.4 to 1.0) for moderate smokers, and 1.3 (1.0 to 1.7) for heavy smokers in men and 1.3 (1.1 to 1.6), 0.7 (0.5 to 1.0), 0.8 (0.5 to 1.0), and 1.1 (0.8 to 1.4), respectively, in women.

Discussion: Among smokers, obesity was associated in a graded manner with the number of cigarettes daily smoked, particularly in men. More emphasis should be put on the risk of obesity among smokers.
Evaluation of Risk Profiles by Subcutaneous Adipose Tissue Topography in Obese Juveniles
Authors: Moeller Reinhard , Horejsi Renate , Pilz Stefan , Lang Nicole , Sargsyan Karine , Dimitrova Roumiana , Tafeit Erwin , Giuliani Albrecht , Almer Gunter , Mangge Harald
Published: July 2008

Objective: To compare subcutaneous adipose tissue topography (SAT‐top) in obese juveniles with age‐matched normal‐weight controls.

Research Methods and Procedures: The optical device LIPOMETER (European Patent EP 0516251) enables the non‐invasive, rapid, safe, and precise measurement of the thickness of subcutaneous adipose tissue. Fifteen defined body sites (1 = neck to 15 = calf) characterize the individual SAT‐top like an individual fingerprint. SAT‐top of 1351 juveniles (obese: 42 boys, 59 girls, normal weight: 680 boys, 570 girls) from 7 to 19 years of age were measured. For visual comparison, the 15‐dimensional SAT‐top information was condensed by factor analysis into a two‐dimensional factor plot.

Results: Both female and male obese juveniles had markedly increased adipose tissue layers at 7 = upper abdomen, 8 = lower abdomen, 5 = front chest, and 6 = lateral chest. The pubertal changes of body shape and fat distribution of the normal‐weight boys and girls (boys show thinner adipose tissue layers on their legs, whereas girls had thicker adipose tissue layers at the extremities) were not seen in the obese group. Independently of age and sex, all of the obese juveniles showed a similar, more android body fat distribution with increased trunk fat.

Discussion: SAT‐top of the obese juveniles is similar to that of patients with type 2 diabetes, polycystic ovary syndrome, and coronary heart disease. Patients with these metabolic disorders and obese juveniles are located in the factor plot in the same area. This body shape may indicate a risk profile for developing polycystic ovary syndrome (women), type 2 diabetes, and early atherosclerosis (both sexes).