bluuebunny/crossref_metadata_2025 huggingface dataset:
An automated, sheathless capillary electrophoresis‐mass spectrometry platform for discovery of biomarkers in human serum
Authors: Sassi Alexander P. , Andel Frank , Bitter Hans‐Marcus L. , Brown Michael P.S. , Chapman Robert G. , Espiritu Jeraldine , Greenquist Alfred C. , Guyon Isabelle , Horchi‐Alegre Mariana , Stults Kathy L. , Wainright Ann , Heller Jonathan C. , Stults John T.
Published: March 2005

A capillary electrophoresis‐mass spectrometry (CE‐MS) method has been developed to perform routine, automated analysis of low‐molecular‐weight peptides in human serum. The method incorporates transient isotachophoresis for in‐line preconcentration and a sheathless electrospray interface. To evaluate the performance of the method and demonstrate the utility of the approach, an experiment was designed in which peptides were added to sera from individuals at each of two different concentrations, artificially creating two groups of samples. The CE‐MS data from the serum samples were divided into separate training and test sets. A pattern‐recognition/feature‐selection algorithm based on support vector machines was used to select the mass‐to‐charge (m/z) values from the training set data that distinguished the two groups of samples from each other. The added peptides were identified correctly as the distinguishing features, and pattern recognition based on these peptides was used to assign each sample in the independent test set to its respective group. A twofold difference in peptide concentration could be detected with statistical significance (p‐value < 0.0001). The accuracy of the assignment was 95%, demonstrating the utility of this technique for the discovery of patterns of biomarkers in serum.
Simulated effect of a forest road on near‐surface hydrologic response and slope stability
Authors: Dutton Anona L. , Loague Keith , Wemple Beverley C.
Published: March 2005

Forest management practices often result in significant changes to hydrologic and geomorphic responses at or near the earth's surface. A well‐known, but not fully tested, hypothesis in hillslope hydrology[sol ]geomorphology is that a near‐surface permeability contrast, caused by the surface compaction associated with forest roads, can result in diverted subsurface flow paths that produce increased up‐slope pore pressures and slope failure. The forest road focused on in this study is located in a steep forested, zero‐order catchment within the H. J. Andrews Experimental Forest (Oregon). A three‐phase modelling effort was employed to test the aforementioned hypothesis: (i) two‐dimensional (vertical slice), steady‐state, heterogeneous, saturated subsurface flow simulations at the watershed scale for establishing the boundary conditions for the catchment‐scale boundary‐value problem in (ii); (ii) two‐dimensional (vertical slice), transient, heterogeneous, variably saturated subsurface flow simulations at the catchment scale for estimating near‐surface hydrologic response and pore pressure distributions; and (iii) slope stability analyses, using the infinite slope approach, driven by the pore pressure distributions simulated in (ii), for assessing the impact of the forest road. Both observed and hypothetical rainfall events are used to drive the catchment‐scale simulations. The results reported here support the hypothesis that a forest road can have an effect on slope stability. The permeability contrast associated with the forest road in this study led to a simulated altering of slope‐parallel subsurface flow with increased pore pressures up‐slope of the road and, for a large rainfall event, a slope failure prediction. Copyright © 2005 John Wiley & Sons, Ltd.
Chloride as a signature indicator of soil textural and hydrologic stratigraphies in variable charge deep profiles
Authors: Rasiah V. , Armour J. D. , Menzies N. W.
Published: March 2005

Soil properties that influence water movement through profiles are important for determining flow paths, reactions between soil and solute, and the ultimate destination of solutes. This is particularly important in high rainfall environments. For highly weathered deep profiles, we hypothesize that abrupt changes in the distribution of the quotient [QT = (silt + sand)/clay] reflect the boundaries between textural units or textural (TS) and hydrologic (HS) stratigraphies. As a result, QT can be used as a parameter to characterize TS and as a surrogate for HS. Secondly, we propose that if chloride distributions were correlated with QT, under non‐limiting anion exchange, then chloride distributions can be used as a signature indicator of TS and HS. Soil cores to a depth of 12·5 m were taken from 16 locations in the wet tropical Johnstone River catchment of northeast Queensland, Australia. The cores belong to nine variable charge soil types and were under sugarcane (Saccharum officinarum‐S) production, which included the use of potassium chloride, for several decades. The cores were segmented at 1 m depth increments and subsamples were analysed for chloride, pH, soil water content (θ), clay, silt and sand contents. Selected bores were capped to serve as piezometers to monitor groundwater dynamics. Depth incremented QT, θ and chloride correlated, each individually, significantly with the corresponding profile depth increments, indicating the presence of textural, hydrologic and chloride gradients in profiles. However, rapid increases in QT down the profile indicated abrupt changes in TS, suggesting that QT can be used as a parameter to characterize TS and as a surrogate for HS. Abrupt changes in chloride distributions were similar to QT, suggesting that chloride distributions can be used as a signature indicator of QT (TS) and HS. Groundwater data indicated that chloride distributions depended, at least partially, on groundwater dynamics, providing further support to our hypothesis that chloride distribution can be used as a signature indicator of HS. Copyright © 2005 John Wiley & Sons, Ltd.
TGF‐β induced hyaluronan synthesis in orbital fibroblasts involves protein kinase C βII activation in vitro
Authors: Wang Hwai‐Shi , Tung Wen‐Hsiu , Tang Kam‐Tsun , Wong Yi‐Kuei , Huang Ging‐Jye , Wu Jiahn‐Chun , Guo Yi‐Jhih , Chen Chin‐Chang
Published: March 2005

Graves' ophthalmopathy is accompanied by hyaluronan (HA) accumulation in the orbital space and infiltration of immunocompetent cells and cytokines, including IFN‐γ, IL‐1β, and TGF‐β. We examined the signal transduction pathways by which TGF‐β induces HA synthesis in normal orbital fibroblasts, orbital fibroblasts from patients with Graves' ophthalmopathy, and abdominal fibroblasts. Calphostin C inhibited the stimulation of HA synthesis by TGF‐β. Phorbol 12‐myristate 13‐acetate (PMA) activation of PKC stimulated HA production. The effects of TGF‐β and PMA were not synergistic. Stimulation by TGF‐β and PMA were dependent on protein synthesis and their effects were inhibited by cycloheximide. Since TGF‐β‐induced HA synthesis was inhibited by BAPTA or by PKC inhibitors, a calcium‐dependent PKC was most likely involved. The PKA inhibitor H‐89 enhanced TGF‐β‐ and PMA‐induced HA synthesis, thus showing that communication between the PKA and PKC pathways was evident. TGF‐β stimulated the translocation of PKCβII to the cell membrane. PKCβII, a key enzyme in the regulation of HA synthesis by TGF‐β, might be an appropriate target for therapeutic compounds to be used to treat Graves' ophthalmopathy accompanied by inflammation. © 2005 Wiley‐Liss, Inc.
Thermodynamic origin of the chiral recognition of tryptophan on teicoplanin and teicoplanin aglycone stationary phases
Authors: Haroun Mohamed , Ravelet Corinne , Ravel Anne , Grosset Catherine , Villet Annick , Peyrin Eric
Published: March 2005

The D‐, L‐tryptophan binding and the chiral recognition properties of the teicoplanin and teicoplanin aglycone (TAG) chiral stationary phase (CSPs) were compared at various column temperatures. The solute adsorption isotherms (bi‐Langmuir model) were determined for both the two CSPs using the perturbation method. It was demonstrated that the sugar units were involved in the reduction of the apparent enantioselectivity through two phenomena: (i) the inhibition of some enantioselective contacts with low‐affinity binding regions of the aglycone and (ii) a decrease in the stereoselective properties of the aglycone high‐affinity binding pocket. The phenomenon (ii) was governed by both a decrease in the ratio of the enantiomer adsorption constant and a strong reduction of the site accessibility for D‐ and L‐tryptophan. In addition, a temperature effect study was performed to investigate the chiral recognition mechanism at the aglycone high‐affinity pocket. An enthalpy‐entropy compensation analysis derived from the Grunwald model as well as the comparison with the literature data demonstrated that the enantioselective binding mode was dependent on an interface dehydration process. The change in the enantioselective process observed between the TAG and teicoplanin CSP was characterized by a difference of ca. 2–3 ordered water molecules released from the species interface.
Multifocal motor neuropathy: Current concepts and controversies
Authors: Nobile‐Orazio Eduardo , Cappellari Alberto , Priori Alberto
Published: March 2005

Multifocal motor neuropathy (MMN) is now a well‐defined purely motor multineuropathy characterized by the presence of multifocal partial motor conduction blocks (CB), frequent association with anti‐GM1 IgM antibodies, and usually a good response to high‐dose intravenous immunoglobulin (IVIg) therapy. However, several issues remain to be clarified in the diagnosis, pathogenesis, and therapy of this condition including its nosological position and its relation to other chronic dysimmune neuropathies; the degree of CB necessary for the diagnosis of MMN; the existence of an axonal form of MMN; the pathophysiological basis of CB; the pathogenetic role of antiganglioside antibodies; the mechanism of action of IVIg treatments in MMN and the most effective regimen; and the treatment to be used in unresponsive patients. These issues are addressed in this review of the main clinical, electrophysiological, immunological, and therapeutic features of this neuropathy. Muscle Nerve, 2005
Sural and radial sensory responses in healthy adults: Diagnostic implications for polyneuropathy
Authors: Esper Gregory J. , Nardin Rachel A. , Benatar Michael , Sax Tracy W. , Acosta Juan A. , Raynor Elizabeth M.
Published: March 2005

We prospectively performed sural and radial sensory nerve conduction studies in 92 healthy subjects, aged between 21 and 88 years, both to determine the lower limits of normal (LLN) and to assess the effects of age and body mass index (BMI) on the sural and radial sensory nerve action potential (SNAP) amplitudes and on the sural/radial amplitude ratio (SRAR). Using the nonparametric bootstrap method to calculate 95% confidence intervals, we found that the 5% LLN values for sural and radial SNAPs were 14 μV and 25.5 μV in subjects aged ≤39 years, 7 μV and 17.4 μV in subjects aged 40–59 years, and 3 μV and 12 μV in subjects aged ≥60 years. The 5% LLN for SRAR for all patients was 0.21. Sural and radial SNAP amplitudes but not SRAR were strongly and inversely correlated with age and BMI. These age‐adjusted normal values and revised SRAR will aid in the electrodiagnosis of polyneuropathy. Muscle Nerve, 2005
Long‐term renal and hearing toxicity of carboplatin in infants treated for localized and unresectable neuroblastoma: Results of the SFOP NBL90 study
Authors: Bergeron C. , Dubourg L. , Chastagner P. , Mechinaud F. , Plouvier E. , Desfachelles A.S. , Dusol F. , Pautard B. , Edan C. , Plantaz D. , Froehlich P. , Rubie H.
Published: March 2005

Background

A secondary end point of the NBL90 protocol (Rubie H et al. Pediatr Oncol 2001;36:247–250) was the concern in this infant population for possible carboplatin‐(CBDCA) induced late side effects including impaired renal and hearing functions.

Procedure

Glomerular filtration rate (GFR), tubular function (TF), pure tone audiometry (PTA), high‐frequency, and transient evoked‐otoacoustic emission were prospectively assessed in 30 children alive and disease‐free 6 years after the end of the treatment.

Results

Median age at diagnosis and at assessment was 4.7 months and 7 years, respectively. Blood pressure was ≤97.5 centile in all children. The mean estimated GFR was 114 ± 13 ml/min/1.73 m2 by Schwartz formula [range 87–145]. TF assessment failed to demonstrate any impairment. 29/30 children had grade 0 ototoxicity and all transient evoked otoacoustic emission were normal.

Conclusions

With a 6‐year follow‐up the combination of VP16 and carboplatin given at conventional doses is safe on renal and hearing functions in infants with unresectable neuroblastomas treated according to SFOP NB90. Pediatr Blood Cancer 2005; 45:32–36. © 2005 Wiley‐Liss, Inc.
Investigation of the microstructure of polypropylene prepared with ansa and fluxional metallocene catalysts with an extended Coleman–Fox model
Authors: Nele Márcio , Pinto José Carlos , Mohammed Muqtar , Collins Scott
Published: March 2005

Temperature (T) effects on the microstructure of polypropylene made with metallocene catalysts have been investigated with the theoretical framework originally developed by Coleman and Fox and extended to the stereospecific polymerization of propylene with two‐state ansa and fluxional metallocene catalysts. T effects on the polymer microstructure are mainly due to factors other than changes in the intrinsic stereoselectivity of the two states. The model has been applied to the stereosequence distributions of polypropylene prepared with the C1‐symmetric Me2Si(Ind)(Flu)ZrCl2 complex, activated with methyl aluminoxane, over a range of T and monomer concentration ([M]) values. The use of these two variables, in combination with the Coleman–Fox model (or a kinetic model), allows more reliable estimates of fundamental parameters, especially when the microstructure is a weak function of one of these variables at a constant value of T (e.g., [M]). © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1797–1810, 2005
Synthesis of ethylene/propylene elastomers containing a terminal reactive group: The combination of metallocene catalysis and control chain transfer reaction
Authors: Kandil U. , Chung T. C.
Published: March 2005

This article discusses a chemical route to prepare new ethylene/propylene copolymers (EP) containing a terminal reactive group, such as ϕ‐CH3 and OH. The chemistry involves metallocene‐mediated ethylene/propylene copolymerization in the presence of a consecutive chain transfer agent—a mixture of hydrogen and styrene derivatives carrying a CH3 (p‐MS) or a silane‐protected OH (St‐OSi). The major challenge is to find suitable reaction conditions that can simultaneously carry out effective ethylene/propylene copolymerization and incorporation of the styrenic molecule (St‐f) at the polymer chain end, in other words, altering the St‐f incorporation mode from copolymerization to chain transfer. A systematic study was conducted to examine several metallocene catalyst systems and reaction conditions. Both [(C5Me4)SiMe2N(t‐Bu)]TiCl2 and rac‐Et(Ind)2ZrCl2, under certain H2 pressures, were found to be suitable catalyst systems to perform the combined task. A broad range of St‐f terminated EP copolymers (EP‐t‐p‐MS and EP‐t‐St‐OH), with various compositions and molecular weights, have been prepared with polymer molecular weight inversely proportional to the molar ratio of [St‐f]/[monomer]. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1858–1872, 2005
Online wide‐angle X‐ray diffraction/small‐angle X‐ray scattering measurements for the CO2‐laser‐heated drawing of poly(ethylene terephthalate) fiber
Authors: Yamaguchi Takayoshi , Komoriyama Kohei , Ohkoshi Yutaka , Urakawa Hiroshi , Gotoh Yasuo , Terasawa Norihisa , Nagura Masanobu , Kajiwara Kanji
Published: March 2005

Fiber‐structure‐development in the poly(ethylene terephthalate) fiber drawing process was investigated with online measurements of wide‐angle and small‐angle X‐ray scattering with both a high‐luminance X‐ray source and a CO2‐laser‐heated drawing system. The intensity profile of the transmitted X‐ray confirmed the location of the neck‐drawing point. The diffraction images had a time resolution of several milliseconds, and this still left much room for improvement. Crystal diffraction appeared in the wide‐angle X‐ray images almost instantaneously about 20 ms after necking, whereas a four‐point small‐angle X‐ray scattering pattern appeared immediately after necking. With the elapse of time after necking, the four‐point scattering pattern changed into a meridional two‐point shape. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 1090–1099, 2005
Hydrogen‐bonding, crystallinity, and morphological properties of poly(silicic acid)/waterborne polyurethane nanocomposites
Authors: Ma Chen‐Chi M. , Su Hsun‐Yu , Kuan Hsu‐Chiang , Kuan Chen‐Feng , Chiang Chin‐Lung
Published: March 2005

Unique nanocomposites consisting of poly(silicic acid) nanoparticles (PNs) and waterborne polyurethane (WPU) were prepared. The aliphatic WPU prepared in this study was end‐capped with a silanol group, which could react with PNs via a sol–gel process. PNs were modified with phenyltrimethoxysilane (PTMS) and 3‐(trimethoxysilyl)propyl ester (TMPE) and then blended with WPU. The structure–property relationships were examined. Solid‐state 29Si NMR spectra of WPU showed that structures T1, T2, and T3 of WPU decreased and structures Q3 and Q4 of PN/WPU nanocomposites increased gradually. When the PN concentration increased to 10 wt %, PN/WPU nanocomposites exhibited the maximum fraction of hydrogen‐bonded carbonyl groups. In the PTMS–PN and TMPE–PN systems, the fraction of hydrogen‐bonded carbonyl groups fluctuated stably when the concentrations of PTMS–PN and TMPS–PN exceeded 5 wt %. The X‐ray diffraction results revealed that α‐form, γ‐form, or triclinic crystallization could be found in the WPU matrix. A differential scanning calorimetry spectrum showed that the crystalline structure of the hard segment of WPU was influenced by the nanoparticle concentration. The degrees of crystallinity were 88% for the PN/WPU nanocomposites, 41% for the PTMS–PN/WPU nanocomposites, and 54% for the TMPE–PN/WPU nanocomposites when the PN, PTMS–PN, and TMPE–PN concentrations were 5 wt %. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 1076–1089, 2005
Icing processes associated with high Arctic perennial springs, Axel Heiberg Island, Nunavut, Canada
Authors: Pollard Wayne H.
Published: March 2005

Saline perennial springs have been documented at six locations on Axel Heiberg Island in the Canadian high Arctic. Spring discharge rates, temperatures and chemistry, and associated icing and frost mound formation have been documented at two locations in the Expedition Fiord area since 1988 and at one location near Whitsunday Bay since 1996. Cold Ca‐ and Na‐rich waters discharge near the base of Gypsum Hill and Colour Peak at Expedition Fiord. A large oval‐shaped icing up to 2 m thick forms at the base of Gypsum Hill while at Colour Peak the springs have formed a series of gullies and travertine deposits which develop three small icing and frost mounds systems in winter. At Whitsunday Bay cold discharge is from a single outlet and is confined by a deep channel where it forms a salt tufa. Where the channel emerges onto the floodplain a large fan‐shaped icing is formed. This paper also documents spring discharge and icing activity from three other non‐glacial sources and one glacial source. The icings and frost mounds formed by these springs are very different from those formed by late summer and early winter subglacial discharge. The high solute concentrations lead to freezing‐point depression, complex patterns of freezing and the formation of brine icings, together with a variety of mineral precipitates. Freezing‐point depression experiments help explain icing hydrology and the spatial pattern of icing formation. Copyright © 2005 John Wiley & Sons, Ltd.
Automated use of mutagenesis data in structure prediction
Authors: Nanda Vikas , DeGrado William F.
Published: March 2005

In the absence of experimental structural determination, numerous methods are available to indirectly predict or probe the structure of a target molecule. Genetic modification of a protein sequence is a powerful tool for identifying key residues involved in binding reactions or protein stability. Mutagenesis data is usually incorporated into the modeling process either through manual inspection of model compatibility with empirical data, or through the generation of geometric constraints linking sensitive residues to a binding interface. We present an approach derived from statistical studies of lattice models for introducing mutation information directly into the fitness score. The approach takes into account the phenotype of mutation (neutral or disruptive) and calculates the energy for a given structure over an ensemble of sequences. The structure prediction procedure searches for the optimal conformation where neutral sequences either have no impact or improve stability and disruptive sequences reduce stability relative to wild type. We examine three types of sequence ensembles: information from saturation mutagenesis, scanning mutagenesis, and homologous proteins. Incorporating multiple sequences into a statistical ensemble serves to energetically separate the native state and misfolded structures. As a result, the prediction of structure with a poor force field is sufficiently enhanced by mutational information to improve accuracy. Furthermore, by separating misfolded conformations from the target score, the ensemble energy serves to speed up conformational search algorithms such as Monte Carlo‐based methods. Proteins 2005. © 2005 Wiley‐Liss, Inc.
Mammotome: Less Invasive than ABBI with Similar Accuracy for Early Breast Cancer Detection
Authors: Weber Walter P. , Zanetti Rosanna , Langer Igor , Dellas Sophie , Zuber Markus , Moch Holger , Remmel Eugenia , Oertli Daniel , Wight Edward , Marti Walter R.
Published: March 2005

We performed a prospective analysis of two consecutive biopsy cohorts investigated by the same team to compare the Mammotome system with the ABBI procedure. From April 1997 to August 2003 a series of 413 nonpalpable mammographic lesions in 387 women (median age 56 years, range 30–84 years) were stereotactically biopsied in the University Hospital of Basel, Switzerland. Until October 1999 the ABBI system was applied exclusively, it was subsequently superseded by the Mammotome device in our clinic. Main outcome measures were accuracy, technical demand, and morbidity. Sensitivity (97.3%/96.8%), negative predictive value (99.2%/98.7%), and diagnostic accuracy (99.4%/99.1%) regarding the detection of malignancy were excellent for both techniques (ABBI/Mammotome). The Mammotome procedure was faster and less invasive, thus causing significantly less morbidity. The larger specimen obtained by the ABBI procedure resulted in more detailed histology. In conclusion, recommend the Mammotome system as the method of choice for detecting nonpalpable early breast cancer.
The Perilous Road from Evidence to Policy: Five Journeys Compared
Authors: BOAZ ANNETTE , PAWSON RAY
Published: March 2005

Comprehensive reviews of the available research are generally considered to be the cornerstone of contemporary efforts to establish ‘evidence-based policy’. This article provides an examination of the potential of this stratagem, using the case study of ‘mentoring’ programmes. Mentoring initiatives (and allied schemes such as ‘coaching’, ‘counselling’, ‘peer education’ and so on) are to be found in every corner of public policy. Researchers have been no less energetic, producing a huge body of evidence on the process and outcomes of such interventions. Reviewers, accordingly, have plenty to get their teeth into and, by now, there are numerous reports offering review-based advice on the benefits of mentoring. The article asks whether the sum total of these efforts, as represented by five contemporary reviews, is a useful tool for guiding policy and practice. Our analysis is a cause for some pessimism. We note a propensity for delivering unequivocal policy verdicts on the basis of ambiguous evidence. Even more disconcertingly, the five reviews head off on different judgemental tangents, one set of recommendations appearing to gainsay the next. The article refrains from recommending the ejection of evidence baby and policy bathwater but suggests that much closer attention needs to be paid to the explanatory scope of systematic reviews.
Cash Versus Services: ‘Worlds of Welfare’ and the Decommodification of Cash Benefits and Health Care Services
Authors: BAMBRA CLARE
Published: March 2005

Welfare state models have focused almost exclusively on the study of cash benefits, and typologies established on this limited basis have been used to generalise about all forms of welfare state provision. This ignores the fact that welfare states are also about the actual delivery of services and/or that countries vary in terms of the relative emphasis that they place upon cash benefits and welfare state services. This article explores the cash and services mix in, and between, welfare states with reference to recent welfare state typologies, most notably Esping-Andersen's decommodification-centred ‘worlds of welfare’. It compares the decommodification levels of the main cash benefits with the main area of service provision: health care. The resulting analysis suggests that when services are added into the comparative analysis of welfare state regimes there are five welfare state clusters: Social Democratic, Liberal, Conservative, and sub-groups within both the Liberal and Conservative regimes. The article concludes that, in order to maintain integrity or generalisability, future welfare state typologies need to reflect more adequately the role of services in welfare state provision.
Pools and distributions of soil phosphorus in China
Authors: Zhang Chi , Tian Hanqin , Liu Jiyuan , Wang Shaoqiang , Liu Mingliang , Pan Shufen , Shi Xuezheng
Published: March 2005

We have investigated the pools and distributions of soil phosphorus (P) in the top 50 cm of soil in China by using a combination of total and available P information from more than 2400 soil profiles and a map of soil types at a resolution of 1:1,000,000. Our estimates indicate that the average total P density and available P density in China are about 8.3 × 102 g/m3 and 5.4 g/m3, respectively. The total national soil P pool in the surface half meter is 3.5 Pg (1015 g). The available P density ranges from 0.7 g/m3 in the Lithosols to 16.7 g/m3 in the Irrigated Silting Soils. The total P density ranges from 1.2 × 102 g/m3 in the Lithosols to 19 × 102 g/m3 in the Frigid Desert Soils. The ratio of available P to total P density ranges from 0.6 × 10−3 in Aeolian Soils to 21.6 × 10−3 in Coastal Solonchaks. The available P content and its vertical distribution show a complex pattern among soil orders of different development stages, possibly indicating the important role of biota's control over soil available P content. There are large variations of P content in different climatic regions. The tropical and subtropical region has the lowest available P density (4.8 g/m3) and the second lowest total P density (8.2 × 102 g/m3) among all climatic regions. The large variation in the soil P content suggests that further study is needed to investigate climatic and land‐use controls over the soil P content.
N isotopic composition of dissolved organic nitrogen and nitrate at the Bermuda Atlantic Time‐series Study site
Authors: Knapp Angela N. , Sigman Daniel M. , Lipschultz Fredric
Published: March 2005

To better constrain the dynamics of the dissolved organic nitrogen (DON) pool and the role of N2 fixation in the nitrogen cycle at the Bermuda Atlantic Time‐series Study (BATS) site, we measured the 15N/14N ratio of total nongaseous nitrogen (TN) in the upper 250 m and of nitrate in the upper 1000 m of monthly water column profiles from June 2000 through May 2001. The annually averaged TN δ15N in the upper 100 m is 3.9‰, which is greater than thermocline nitrate (2–3‰ at 250 m) and similar to literature values for shallow sinking nitrogen at BATS (3.7‰). We discern no seasonal variation in TN δ15N, which suggests that most of the DON pool is recalcitrant on this timescale. The TN data require a δ15N for the sinking flux that is similar to previous measurements, suggesting that N2 fixation is a minor component of new nitrogen at BATS. Small but measurable differences in the concentration and 15N/14N of total organic nitrogen (TON) between the surface and subsurface (∼250 m) suggest that subsurface remineralization of ∼0.25 μM of the surface TON acts to lower the 15N/14N of nitrate in the thermocline at BATS.
Solubility of fluorite in haplogranitic melt of variable alkalis and alumina content at 800°–1000°C and 100 MPa
Authors: Gabitov R. I. , Price J. D. , Watson E. B.
Published: March 2005

To study the behavior of fluorite in SiO2‐Al2O3‐Na2O‐K2O‐H2O melts, we conducted both crystallization and dissolution experiments. In the first case, fluorite crystallized from melts enriched in Ca relative to F. In the second case, ground fluorite (<10 μm) was partially dissolved into melts of initially F‐free or F‐doped glass. Experiments were conducted at 800°–1000°C and 100 MPa for 7 to 240 hours using a series of finely ground subaluminous and peralkaline haplogranitic glasses. Electron microprobe (EMP) analysis of the run products (glass + crystals) documented increasing fluorite solubility with melt alkalinity. These molar relationships can be described by CF/2 = −1.3 · ASI + 2.3 at 900°C and CF/2 = CCa = −2.1 · ASI + 3.8 at 1000°C, where ASI is the aluminum saturation index measured in experimental glasses as Al/(Na + K + 2Ca), CF/2 is one half the molar concentration (%) of F, and CCa is the mol% of Ca in the glass. Fluorite solubility may be defined as either CF/2, CCa, or both. Solubilities at 800°, 900°, and 1000°C for the melts with ASI between 0.58 and 0.59 approach log linear with 104/T(K) (slope = −0.45). The joint effect of F and temperature on fluorite solubility is significant: solubility rises from 0.28 mol% at 800°C (4.96 mol% doped F) to 0.99 mol% at 900°C (2.17 mol% doped F). Solubilities at 800°, 850°, and 900°C for the melts with the same initial F contents (4.96 mol%) approach log linear with 104/T(K) (slope = −0.33).
Meta‐analysis of tropical surface temperatures during the Last Glacial Maximum
Authors: Ballantyne A. P. , Lavine M. , Crowley T. J. , Liu J. , Baker P. B.
Published: March 2005

The magnitude of tropical cooling during the Last Glacial Maximum (LGM) has been the subject of uncertainty for over 25 years. We use principles of meta‐analysis as an objective approach to reconcile estimates from different proxies. This approach treats each observation as a random estimate of the true mean and weights estimates by their reported precision. We assigned global uncertainties to proxies and derived a new regional standard deviation for temperatures calculated from the Sr/Ca ratio in tropical corals (σ = 1.4°C). Using a Bayesian spatial interpolation scheme, we estimate a mean cooling of LGM tropical sea surface temperatures of −2.7 ±0.5°C (±σ) and surface air temperatures of −5.4 ±0.3°C (±σ).
Snowpack radiative heating: Influence on Tibetan Plateau climate
Authors: Flanner Mark G. , Zender Charles S.
Published: March 2005

Solar absorption decays exponentially with depth in snowpacks. However, most climate models constrain all snowpack absorption to occur uniformly in the top‐most snow layer. We show that 20–45% of solar absorption by deep snowpacks occurs more than 2 cm beneath the surface. Accounting for vertically‐resolved solar heating alters steady‐state snow mass without changing bulk snow albedo, and ice‐albedo feedback amplifies this effect. Vertically‐resolved snowpack heating reduces winter snow mass on the Tibetan Plateau by 80% in one GCM, and significantly increases 2 m air temperature. These changes significantly reduce model‐measurement discrepancies. Our results demonstrate that snowpack radiative heating plays a significant role in regulating surface climate and hydrology. More accurate snowpack radiation has the potential to improve predictions of related climate processes, such as spring runoff and the Asian Monsoon.
Observations of ionospheric plasma flows within theta auroras
Authors: Liou K. , Ruohoniemi J. M. , Newell P. T. , Greenwald R. , Meng C.‐I. , Hairston M. R.
Published: March 2005

This paper reports results from a detailed analysis of theta auroras that occurred during the passage of a magnetic cloud on 8 November 2000. The interplanetary magnetic field (IMF) was generally northward for more than 12 hours, while the y‐component of the IMF changed signs several times. Auroral images of the Northern Hemisphere acquired from the Ultraviolet Imager (UVI) on board the Polar satellite showed clear development of theta auroras during the prolonged northward IMF period. It is found that the theta aurora can be enhanced by compression of the magnetosphere associated solar wind pressure pulses. We also examine large‐scale ionospheric plasma convection flow data from the SuperDARN radar network to study the ionospheric plasma flow pattern associated with the theta aurora. The radar data, when available, showed that two different plasma flows can coexist within the day‐night part of the theta aurora. The nightside extension of the theta aurora is always on a region of antisunward convecting flows, whereas there is no consistent flow pattern found in the dayside portion of the theta aurora studied. In general, plasma flow outside the theta aurora cannot be determined because of lack of scattered radar signals, but from a few instances it suggested that the nightside theta aurora is flanked by antisunward flows. In contrast to the prevailing view that theta auroras reside in regions of closed magnetic flux that convect sunward, this study suggests one more aspect of the theta aurora and provides constraints for models and theories.
Mineralogy and elasticity of the oceanic upper mantle: Origin of the low‐velocity zone
Authors: Stixrude Lars , Lithgow‐Bertelloni Carolina
Published: March 2005

We use a new method to construct an upper mantle model based on self‐consistent computation of phase equilibria and physical properties. Computation of the isotropic elastic wave velocities of a pyrolytic bulk composition in thermodynamic equilibrium shows a distinct low‐velocity zone with a minimum velocity VS = 4.47 km s−1 along the 100 Ma geotherm. In the vicinity of the low‐velocity zone the velocity of this null hypothesis is approximated along oceanic geotherms by VS = 4.77 + 0.0380(P, z/29.80) − 0.000378(T − 300), with pressure P in GPa, depth z in km, temperature T in K, and velocity VS in km s−1. The null hypothesis predicts a minimum VS 0.1–0.2 km s−1 higher than that in seismological models of 100 Ma Pacific. We find that dispersion, estimated solely on the basis of seismological attenuation models, can account for this residual velocity deficit. Except in the immediate vicinity of the ridge (t < 5 Ma), a solid‐state low‐velocity zone provides a satisfactory quantitative explanation of seismic observations. We do not find a satisfactory explanation for the magnitude of the Gutenberg discontinuity or for the high shear wave velocity gradient zone.
The Politics of Emotion in Everyday Life: “Appropriate” Emotion and Claims on Identity
Authors: Shields Stephanie A.
Published: March 2005

Emotions have a political dimension in that judgments regarding when and how emotion should be felt and shown are interpreted in the interests of regulating the organization and functioning of social groups. This article argues that claims to authenticity and legitimacy of one's self-identity or group identity are at stake in the everyday politics of emotion. A brief discussion of the study of sex differences in the 19th century illustrates how emotion politics can saturate even scientific inquiry. Three ways in which there is a political dimension to socially appropriate emotion in contemporary life are then discussed: (a) Is the emotion the “wrong” emotion for the situation? (b) How are competing standards for emotional experience and expression managed? and (c) What constitutes the boundary between “too much” and “too little” emotion? The author concludes by considering the relevance of emotion politics to research on emotion.
Nonlinear charge injection in organic field-effect transistors
Authors: Hamadani B. H. , Natelson D.
Published: March 2005

Transport properties of a series of poly(3-hexylthiophene) organic field-effect transistors with Cr, Cu, and Au source∕drain electrodes were examined over a broad temperature range. The current–voltage characteristics of the injecting contacts are extracted from the dependence of conductance on channel length. With reasonable parameters, a model of hopping injection into a disordered density of localized states, with emphasis on the primary injection event, agrees well with the field and the temperature dependence of the data over a broad range of temperatures and gate voltages.
Elusive contribution of the experimental surface molecular electrostatic potential and promolecule approximation in the empirical estimate of the crystal density
Authors: Bouhmaida Nouzha , Ghermani Nour Eddine
Published: March 2005

The aim of this study is to probe the crystal density (Dc) description in terms of pertinent molecular characteristics and properties. In this purpose, the electrostatic potential was derived from available experimental electron density multipole parameters of molecular compounds with different Dc magnitudes. The surface electrostatic potential has been analyzed through the positive and negative statistical variances. The surface of the molecule is here corresponding to particular isodensity values according to Bader’s topological theory. Following the successful Politzer’s method based on quantum mechanics calculations to empirically describe macroscopic properties, the crystal density was regressed on the molecular density and the surface electrostatic potential variance. This latter appears to be a poor statistical descriptor of the crystal density when the experimentally derived electrostatic potential is used and it does not significantly improve the fit of Dc to molecular density alone. Compared to Politzer’s approach based on gas phase isolated molecules, the experimental electrostatic potential is biased by the interactions in the crystal lattice. As an alternative to other sophisticated methods, the promolecule isodensity surface offers a quite useful and straightforward way to define the molecular volumes. The reported description of the crystal density for a set of 50 molecules using the promolecule approach yields satisfactory results.
Variable-separation theory for the null Hamilton–Jacobi equation
Authors: Benenti S. , Chanu C. , Rastelli G.
Published: March 2005

The theory of the separation of variables for the null Hamilton–Jacobi equation H=0 is systematically revisited and based on Levi–Civita separability conditions with Lagrangian multipliers. The separation of the null equation is shown to be equivalent to the ordinary separation of the image of the original Hamiltonian under a generalized Jacobi–Maupertuis transformation. The general results are applied to the special but fundamental case of the orthogonal separation of a natural Hamiltonian with a fixed value of the energy. The separation is then related to conditions which extend those of Stäckel and Kalnins and Miller (for the null geodesic case) and it is characterized by the existence of conformal Killing two-tensors of special kind.
Role of hydrogen bonds in the fast dynamics of binary glasses of trehalose and glycerol: A molecular dynamics simulation study
Authors: Dirama Taner E. , Carri Gustavo A. , Sokolov Alexei P.
Published: March 2005

Trehalose-glycerol mixtures are known to be effective in the long time preservation of proteins. However, the microscopic mechanism of their effective preservation abilities remains unclear. In this article we present a molecular dynamics simulation study of the short time, less than 1ns, dynamics of four trehalose-glycerol mixtures at temperatures below the glass transition temperature. We found that a mixture of 5% glycerol and 95% trehalose has the most suppressed short time dynamics (fast dynamics). This result agrees with the experimental analysis of the mean-square displacement of the hydrogen atoms, as measured via neutron scattering, and correlates with the experimentally observed enhancement of the stability of some enzymes at this particular concentration. Our microscopic analysis suggests that the formation of a robust intermolecular hydrogen bonding network is most effective at this concentration and is the main mechanism for the suppression of the fast dynamics.
Characterizing seismic noise in the 2–20 Hz band at a gravitational wave observatory
Authors: Coward D. , Turner J. , Blair D. , Galybin K.
Published: March 2005

We present a study of seismic noise, using an array of seismic sensors, at the Australian International Gravitational Observatory. We show that despite excellent attenuation of 2–20 Hz seismic waves from the soil properties of the site, which is confirmed by a specific experiment, there are important technical issues associated with local sources of vibration originating from within the laboratory buildings. In particular, we identify vibrations from air-filtration equipment propagating throughout the site. We find significant building resonances in the 2–13 Hz band and identify seismic noise originating from regional mine blasts hundreds of kilometers distant. All these noise sources increase the performance requirements on vibration isolation in the 2–20 Hz frequency band.
Comparison of in-plane and out-of-plane optical amplification in AFM measurements
Authors: Peter F. , Rüdiger A. , Waser R. , Szot K. , Reichenberg B.
Published: March 2005

The in-plane image of piezoresponse force microscopy (PFM) generally exhibits a higher resolution and less noise than the out-of-plane image. Geometrical considerations indicate that the optical in-plane amplification is ≈40 times larger than the out-of-plane amplification. We experimentally confirm this explanation in a dedicated setup.
Field programmable gate array time counter with two-stage interpolation
Authors: Szymanowski Rafal , Kalisz Józef
Published: March 2005

This paper presents a precise time counter with two two-stage interpolators, integrated in a field-programmable gate array device. Interpolation is performed by a single tapped delay line with dual synchronizers in the first stage and a differential tapped delay line in the second stage. The delay-locked loop is used for indirect stabilization of the propagation time of delay elements. The counter has 200ps resolution over the measurement range of 0–167ms with the standard measurement uncertainty below 140ps. A detailed analysis of influence of the flip–flop metastability on the counter accuracy is also presented.
Multiwalled carbon nanotube/BaTiO3 nanocomposites: Electrical and rectification properties
Authors: Huang Qing , Gao Lian
Published: March 2005

Multiwalled carbon nanotube (MWNT)∕BaTiO3 functional nanocomposites were fabricated via the spark plasma sintering technique. The resistivity of MWNT∕BaTiO3 nanocomposites was found higher than that of MWNT-free BaTiO3 ceramics. In addition, the temperature dependence of resistivity showed abnormal metallic conductance behavior in the 1wt.% MWNT∕BaTiO3 nanocomposite. It was proposed to be due to the additional subgrain boundary between MWNT and BaTiO3 matrix, which led to transformation from an impurity-scattering mechanism to a dominant lattice-scattering mechanism in the MWNT∕BaTiO3 nanocomposites as the content of carbon nanotubes increased. Based on observed unique electrical properties, bilayer ceramics stacked by one layer of MWNT-free BaTiO3 and another layer of MWNT∕BaTiO3 nanocomposite were fabricated and showed excellent rectification property.
Effects of chemical modifications on the thermal conductivity of carbon nanotube composites
Authors: Liu C. H. , Fan S. S.
Published: March 2005

Interfaces and close proximity between carbon nanotubes (CNTs) and the matrix are very important for their thermal conductance of CNT composites. Chemical modifications to the CNTs are a possible approach to manage the interfacial interactions. In this study, the nanocomposites of the polydimethylsiloxanerubber with 2wt% chemical-treated CNTs loading were prepared to investigate the influence of chemical modifications and defects on the thermal conductivity of CNT composites. The CNTs treated in concentrated nitric acid showed remarkable changes which could be seen directly by their morphologies. The thermal conductivities κ of the composites were measured carefully in comparison with that by the raw CNT loading. The κ varied somewhat up and down with the treatment level. This study reveals that moderate chemical modifications are beneficial to improve the thermal conductivity of the CNT composites. However, their negative effects to the thermal conductance are more remarkable than the theoretical anticipation.
Receptor-induced depletion of phosphatidylinositol 4,5-bisphosphate inhibits inwardly rectifying K+channels in a receptor-specific manner
Authors: Cho Hana , Lee Doyun , Lee Suk Ho , Ho Won-Kyung
Published: March 2005

Phosphatidylionsitol 4,5-bisphosphate (PIP2), a substrate of phospholipase C, has recently been recognized to regulate membrane-associated proteins and act as a signal molecule in phospholipase C-linked Gq-coupled receptor (GqPCR) pathways. However, it is not known whether PIP2depletion induced by GqPCRs can act as receptor-specific signals in native cells. We investigated this issue in cardiomyocytes where PIP2-dependent ion channels, G protein-gated inwardly rectifying K+(GIRK) and inwardly rectifying background K+(IRK) channels, and various GqPCRs are present. The GIRK current was recorded by using the patch-clamp technique during the application of 10 μM acetylcholine. The extent of receptor-mediated inhibition was estimated as the current decrease over 4 min while taking the GIRK current (IGIRK) value during a previous stimulation as the control. Each GqPCR agonist inhibitedIGIRKwith different potencies and kinetics. The extents of inhibition induced by phenylephrine, angiotensin II, endothelin-1, prostaglandin F2α, and bradykinin at supramaximal concentrations were (mean ± SE) 32.1 ± 0.6%, 21.9 ± 1.4%, 86.4 ± 1.6%, 63.7 ± 4.9%, and 5.7 ± 1.9%, respectively. GqPCR-induced inhibitions ofIGIRKwere not affected by protein kinase C inhibitor (calphostin C) but potentiated and became irreversible when the replenishment of PIP2was blocked by wortmannin (phosphatidylinositol kinase inhibitor). Loading the cells with PIP2significantly reduced endothelin-1 and prostaglandin F2α-induced inhibition ofIGIRK. On the contrary, GqPCR-mediated inhibitions of inwardly rectifying background K+currents were observed only when GqPCR agonists were applied with wortmannin, and the effects were not parallel with those onIGIRK. These results indicate that GqPCR-induced inhibition of ion channels by means of PIP2depletion occurs in a receptor-specific manner.