bluuebunny/crossref_metadata_2025 huggingface dataset:
Membrane inclusions as coupled harmonic oscillators: Effects due to anisotropic membrane slope relaxation
Authors: Partenskii Michael B. , Miloshevsky Gennady V. , Jordan Peter C.
Published: March 2004

Membrane-mediated interaction between membrane-spanning peptides or protein segments plays an important role in their function and stability. Our rigorous “coupled harmonic oscillators” representation is extended to account for the complex boundary conditions permitting anisotropic relaxation of the membrane slope along the contours of the inclusions. Using this representation and applying a highly efficient finite-difference algorithm, we have analyzed the membrane-mediated interaction triggered by deformation of the hydrophobic tails of lipid molecules to match the lipophilic exterior of the inserted peptide. We establish that anisotropic relaxation crucially affects the interaction energy, leading to a short-range attraction between two inclusions, while conventional isotropic boundary conditions result in their strong repulsion. In a multi-inclusion cluster, this attraction is further enhanced and modified due to nonpairwise interactions. The results for dimyristoyl phosphatidylcholine and glyceryl monooleate membranes are compared, and the effects of the inclusion radius are considered. The possible role of slope relaxation in the reported stabilization of linked gramicidin channels and in proteins’ functional cooperativity is outlined.
Broadband femtosecond sum-frequency spectroscopy of CO on Ru{101̄0} in the frequency and time domains
Authors: Symonds Jonathan P. R. , Arnolds Heike , Zhang Vanessa L. , Fukutani Katsuyuki , King David A.
Published: March 2004

CO on Ru{101̄0} was investigated by broadband femtosecond sum-frequency spectroscopy at 200 K. Approximately half of the frequency shift of 71 cm−1 over the coverage range from 0.15 to 1.22 monolayers is shown to originate from dipole–dipole coupling, with the remainder due to a chemical shift. Despite low adlayer-surface registration at the highest coverages, the linewidth of the C–O stretch is comparatively low, and is described by homogeneous broadening according to sum-frequency free-induction decay measurements in the time domain. This can be explained by the dominance of the CO dipole coupling strength over the static disorder present in a coincidence structure. As the coverage decreases below 0.3 monolayer, the linewidth increases considerably, indicative of inhomogeneous broadening. Supported by a concomitant frequency change we suggest that at low coverages CO molecules form chains of irregular length in the [0001] direction, as has been shown for other surfaces with similar symmetry.
Kinetics of the CO oxidation reaction on Pt(111) studied byin situhigh-resolution x-ray photoelectron spectroscopy
Authors: Kinne M. , Fuhrmann T. , Zhu J. F. , Whelan C. M. , Denecke R. , Steinrück H.-P.
Published: March 2004

High-resolution x-ray photoelectron spectroscopy has been used to study the kinetics of the CO oxidation reaction on a Pt(111) surface in situ. The study focuses on the interaction of a preadsorbed p(2×2) layer of atomic oxygen with CO dosed using a supersonic molecular beam. Measurements of O 1s and C 1s spectra at 120 K show that CO adsorbs on the oxygen precovered substrate, but no reaction occurs. A maximum CO coverage of 0.23 ML (monolayer) is observed, with CO exclusively bound on on-top sites. In accordance with the literature, bridge sites are blocked by the presence of atomic oxygen. The reaction of CO with preadsorbed O to CO2 is studied isothermally in a temperature range between 275 and 305 K. The reaction rate initially increases with CO pressure, but saturates at 9×10−7 mbar. The data indicate that a certain amount of disordered oxygen within the p(2×2) layer acts as a starting point of the reaction and for a given temperature reacts with a higher rate than O in the well-ordered oxygen p(2×2) phase. For the reaction of CO with this ordered phase, the results confirm the assumption of a reaction mechanism, which is restricted to the edges of compact oxygen islands. The activation energy of the reaction is determined to (0.53±0.04) eV, with a prefactor of 4.7×106±0.7 s−1.
Infrared spectroscopy of the solid phases of ammonia
Authors: Holt Jennifer S. , Sadoskas David , Pursell Christopher J.
Published: March 2004

Thin films of solid ammonia (NH3 and ND3) have been characterized using low temperature (25–110 K) Fourier-transform infrared (FTIR) spectroscopy, and the three solid phase (amorphous, metastable, and crystalline) spectra are reported. This work has been motivated by confusion in the literature about the metastable and crystalline phases as a result of an early erroneous report by Staats and Morgan [(J. Chem. Phys. 31, 553 (1959)]. Although the crystalline phase has subsequently been reported correctly, the metastable phase has not been described in the literature in detail. The unique characteristics of the metastable phase, reported here for the first time, include multiple peaks in the ν2 and ν3 regions and peak intensities that are dependent on the deposition temperature. This behavior may be the result of (a) preferential molecular orientations in the solid, or (b) exciton splitting due to different crystal shapes in the solid. The amorphous and metastable phases of deuterated ammonia are also reported for the first time.
Threshold-photoelectron-spectroscopy-coincidence study of the double photoionization of HBr
Authors: Alagia Michele , Brunetti Brunetto G. , Candori Pietro , Falcinelli Stefano , Teixidor Marc Moix , Pirani Fernando , Richter Robert , Stranges Stefano , Vecchiocattivi Franco
Published: March 2004

A threshold-photoelectron-coincidence spectrum of HBr has been recorded in the 32.2–35.8 eV photon energy range, with a resolution of ∼0.01 eV, using a synchrotron radiation source. The X 3Σ− and a 1Δ2 states of the HBr2+ dication are clearly observed in the spectrum, while there is no clear evidence for the formation of the b 1Σ+ electronic state. For the first two states, the vibrational states v=0–3 have been resolved, while for the ground X 3Σ− state also spin–orbit splitting has been detected. The results appear in good agreement with previous experimental observations. A comparison with theoretical predictions indicates the role of “noncovalent” contributions to the interaction between the two atomic partners for the formation of metastable states.
Unified treatment of chemical and van der Waals forces via symmetry-adapted perturbation expansion
Authors: Patkowski Konrad , Jeziorski Bogumil , Szalewicz Krzysztof
Published: March 2004

We propose a symmetry-adapted perturbation theory (SAPT) expansion of the intermolecular interaction energy which in a finite order provides the correct values of the constants determining the asymptotics of the interaction energy (the van der Waals constants) and is convergent when the energy of the interacting system is submerged in the continuum of Pauli-forbidden states—the situation common when at least one of the monomers has more than two electrons. These desirable features are achieved by splitting the intermolecular electron–nucleus attraction terms of the Hamiltonian into regular (long-range) and singular (short-range) parts. In the perturbation theory development, the regular part is treated as in the conventional polarization theory, which guarantees the correct asymptotics of the interaction energy, while the singular part is weakened sufficiently by an application of permutational symmetry projectors so that a convergent perturbation series is obtained. The convergence is demonstrated numerically, for both the chemical and van der Waals minima, by performing high-order calculations of the interaction energy of the ground-state lithium and hydrogen atoms—the simplest system for which the physical ground state is submerged in the Pauli-forbidden continuum. The obtained expansion enables a systematic extension of SAPT calculations beyond second order with respect to the intermolecular interaction operator.
Gold particle interaction in regular arrays probed by surface enhanced Raman scattering
Authors: Félidj N. , Truong S. Lau , Aubard J. , Lévi G. , Krenn J. R. , Hohenau A. , Leitner A. , Aussenegg F. R.
Published: March 2004

Lithographically designed two-dimensional arrays consisting of gold nanoparticles deposited on a smooth gold film are used as substrate to examine the SERS effect of the trans-1,2-bis (4-pyridyl) ethylene molecule. These arrays display two plasmon bands instead of the single one observed for the same arrays of particles but deposited on indium tin oxide coated glass. Laser excitation within the short wavelength band does not bring about any SERS spectrum, while excitation within the long wavelength band yields SERS spectra with a gain per molecule rising up to 108. The simultaneous investigation of extinction and Raman spectra of arrays exhibiting various topography parameters enables us to suggest an interpretation for both the occurrence of the two plasmon resonances and for the high Raman enhancement. We suggest to assign the short wavelength band to a plasmon wave propagating at the gold glass interface and the long wavelength one to an air/gold surface plasmon mode modified by particle–particle interaction.
Microscopic theory of gelation and elasticity in polymer–particle suspensions
Authors: Chen Yeng-Long , Schweizer Kenneth S.
Published: March 2004

A simplified mode-coupling theory (MCT) of ergodic–nonergodic transitions, in conjunction with an accurate two-component polymer reference interaction site model (PRISM) theory for equilibrium structural correlations, has been systematically applied to investigate gelation, localization, and elasticity of flexible polymer-hard particle suspensions. The particle volume fraction at the fluid–gel transition is predicted to depend exponentially on reduced polymer concentration and size asymmetry ratio at relatively high colloid concentrations. In contrast, at lower particle volume fractions, a power-law dependence on polymer concentration is found with effective exponents and prefactors that depend systematically on the polymer/particle size ratio. Remarkable power-law and near universal scaling behavior is found for the localization length and elastic shear modulus. Multiple experiments for gel boundaries and shear moduli are in good agreement with the no adjustable parameter theory. The one exception is the absolute magnitude of the shear modulus which is strongly overpredicted, apparently due to nonequilibrium dense cluster formation. The simplified MCT-PRISM theory also captures the qualitative aspects of the weak depletion-driven “glass melting” phenomenon at high particle volume fractions. Calculations based on an effective one-component model of structure within a low particle volume fraction framework yield qualitatively different features than the two-component approach and are apparently all in disagreement with experiments. This suggests that volume fraction and size asymmetry dependent many-body screening of polymer-mediated depletion attractions at finite particle concentrations are important.
Electrofreezing of confined water
Authors: Zangi Ronen , Mark Alan E.
Published: March 2004

We report results from molecular dynamics simulations of the freezing transition of TIP5P water molecules confined between two parallel plates under the influence of a homogeneous external electric field, with magnitude of 5 V/nm, along the lateral direction. For water confined to a thickness of a trilayer we find two different phases of ice at a temperature of T=280 K. The transformation between the two, proton-ordered, ice phases is found to be a strong first-order transition. The low-density ice phase is built from hexagonal rings parallel to the confining walls and corresponds to the structure of cubic ice. The high-density ice phase has an in-plane rhombic symmetry of the oxygen atoms and larger distortion of hydrogen bond angles. The short-range order of the two ice phases is the same as the local structure of the two bilayer phases of liquid water found recently in the absence of an electric field [J. Chem. Phys. 119, 1694 (2003)]. These high- and low-density phases of water differ in local ordering at the level of the second shell of nearest neighbors. The results reported in this paper, show a close similarity between the local structure of the liquid phase and the short-range order of the corresponding solid phase. This similarity might be enhanced in water due to the deep attractive well characterizing hydrogen bond interactions. We also investigate the low-density ice phase confined to a thickness of 4, 5, and 8 molecular layers under the influence of an electric field at T=300 K. In general, we find that the degree of ordering decreases as the distance between the two confining walls increases.
The surprising nonlinear optical properties of conjugated polyyne oligomers
Authors: Slepkov Aaron D. , Hegmann Frank A. , Eisler Sara , Elliott Erin , Tykwinski Rik R.
Published: March 2004

Polyynes represent a unique class of conjugated organic compounds. The third-order nonlinear optical response of polyynes has been extensively modeled theoretically, and it is generally believed that the increase in molecular second hyperpolarizability (γ) as a function of length for polyynes should be lower than that for polyenes. Experimental evidence to test this prediction, however, has been absent. We have synthesized conjugated polyynes that contain up to 20 consecutive sp-hybridized carbons, and we have determined their nonresonant γ-values as a function of the number of acetylene repeat units (n). These γ-values demonstrate a power-law behavior versus n(γ∼n4.28±0.13), with an exponent that is both larger than theoretically predicted for polyynes and substantially higher than that observed for polyenes or polyenynes. Furthermore, no saturation of the linear or nonlinear optical properties is observed.
Effect of salinity on the growth of chicory (Cichorium intybus cv. Puna) — a potential dairy forage species for irrigation areas
Authors: Boyd D. C. , Rogers M. E.
Published: March 2004

Chicory (Cichorium intybus L.) cv. Puna, a potentially useful forage species for dairy cows is reported anecdotally to have moderate salt tolerance and its tolerance to saline conditions was evaluated in a greenhouse experiment at Tatura, Victoria. Plants were grown hydroponically at 5 salinity levels (0, 50, 100, 150 and 200�mmol/L NaCl) along with plants of 4 other broadleafed species, lucerne (Medicago sativa) cvv. Salado and L52, white clover (Trifolium repens) cv. Victorian Irrigation and strawberry clover (Trifolium fragiferum) cv. Palestine.Plant survival rates were high for all species at all salinity levels but all plants species showed symptoms of being salt-affected, and had slower and more stunted growth at the higher salinity levels. Chicory produced significantly (P<0.05) more plant dry matter over the range of salinity levels compared with the other 4 species. Both the lucerne cultivars produced more (P<0.05) dry matter than strawberry and white clover and cv. Salado produced significantly (P<0.05) more dry matter than the other lucerne cultivar, L52. No differences were apparent between the 2 clover species, and these species were clearly the lowest yielding in terms of dry matter production. In relative terms (yield in saline conditions as compared with that in non-saline conditions), there were no significant differences between any of the 4 plant species. Dry matter digestibility levels increased in all species with increasing external salinity levels and ranged from 70 to 88%.These results suggest that chicory has a degree of salt tolerance that is similar to lucerne and therefore could be an alternative dairy forage species in moderately saline areas and on farms that use pumped saline groundwater for irrigation. However, further assessments of its salt tolerance under field conditions are recommended.
Characterization of a hypercontraction-induced myopathy in Drosophila caused by mutations in Mhc
Authors: Montana Enrico S. , Littleton J. Troy
Published: March 2004

The Myosin heavy chain (Mhc) locus encodes the muscle-specific motor mediating contraction in Drosophila. In a screen for temperature-sensitive behavioral mutants, we have identified two dominant Mhc alleles that lead to a hypercontraction-induced myopathy. These mutants are caused by single point mutations in the ATP binding/hydrolysis domain of Mhc and lead to degeneration of the flight muscles. Electrophysiological analysis in the adult giant fiber flight circuit demonstrates temperature-dependent seizure activity that requires neuronal input, as genetic blockage of neuronal activity suppresses the electrophysiological seizure defects. Intracellular recordings at the third instar neuromuscular junction show spontaneous muscle movements in the absence of neuronal stimulation and extracellular Ca2+, suggesting a dysregulation of intracellular calcium homeostasis within the muscle or an alteration of the Ca2+ dependence of contraction. Characterization of these new Mhc alleles suggests that hypercontraction occurs via a mechanism, which is molecularly distinct from mutants identified previously in troponin I and troponin T.
PKCα mediates TGFβ-induced growth inhibition of human keratinocytes via phosphorylation of S100C/A11
Authors: Sakaguchi Masakiyo , Miyazaki Masahiro , Sonegawa Hiroyuki , Kashiwagi Mariko , Ohba Motoi , Kuroki Toshio , Namba Masayoshi , Huh Nam-ho
Published: March 2004

Growth regulation of epithelial cells is of major concern because most human cancers arise from them. We demonstrated previously a novel signal pathway involving S100C/A11 for high Ca2+-induced growth inhibition of normal human keratinocytes (Sakaguchi, M., M. Miyazaki, M. Takaishi, Y. Sakaguchi, E. Makino, N. Kataoka, H. Yamada, M. Namba, and N.H. Huh. 2003. J. Cell Biol. 163:825–835). This paper addresses a question whether transforming growth factor β (TGFβ) shares the pathway with high Ca2+. On exposure of the cells to TGFβ1, S100C/A11 was phosphorylated, bound to nucleolin, and transferred to the nucleus, resulting in induction of p21WAF1/CIP1 and p15INK4B through activation of Sp1. Protein kinase C α (PKCα) was shown to phosphorylate 10Thr of S100C/A11, which is a critical event for the signal transduction. The TGFβ1-induced growth inhibition was almost completely mitigated when PKCα activity was blocked or when S100C/A11 was functionally sequestered. These results indicate that, in addition to the well-characterized Smad-mediated pathway, the PKCα–S100C/A11-mediated pathway is involved in and essential for the growth inhibition of normal human keratinocytes cells by TGFβ1.
Golgi inheritance
Authors: Barr Francis A.
Published: March 2004

Our view of what happens to the Golgi and ER during mitosis in mammalian cells has been shaken once more. Rather than the Golgi contents being recycled through, or mixed with the ER, two recent studies taking complementary approaches, find that the contents of these organelles remain separate throughout mitosis.
Regulation of Kir Channels by Intracellular pH and Extracellular K+
Authors: Dahlmann Anke , Li Min , Gao ZhongHua , McGarrigle Deirdre , Sackin Henry , Palmer Lawrence G.
Published: March 2004

ROMK channels are regulated by internal pH (pHi) and extracellular K+ (K+o). The mechanisms underlying this regulation were studied in these channels after expression in Xenopus oocytes. Replacement of the COOH-terminal portion of ROMK2 (Kir1.1b) with the corresponding region of the pH-insensitive channel IRK1 (Kir 2.1) produced a chimeric channel (termed C13) with enhanced sensitivity to inhibition by intracellular H+, increasing the apparent pKa for inhibition by ∼0.9 pH units. Three amino acid substitutions at the COOH-terminal end of the second transmembrane helix (I159V, L160M, and I163M) accounted for these effects. These substitutions also made the channels more sensitive to reduction in K+o, consistent with coupling between the responses to pHi and K+o. The ion selectivity sequence of the activation of the channel by cations was K+ ≅ Rb+ > NH4+ >> Na+, similar to that for ion permeability, suggesting an interaction with the selectivity filter. We tested a model of coupling in which a pH-sensitive gate can close the pore from the inside, preventing access of K+ from the cytoplasm and increasing sensitivity of the selectivity filter to removal of K+o. We mimicked closure of this gate using positive membrane potentials to elicit block by intracellular cations. With K+o between 10 and 110 mM, this resulted in a slow, reversible decrease in conductance. However, additional channel constructs, in which inward rectification was maintained but the pH sensor was abolished, failed to respond to voltage under the same conditions. This indicates that blocking access of intracellular K+ to the selectivity filter cannot account for coupling. The C13 chimera was 10 times more sensitive to extracellular Ba2+ block than was ROMK2, indicating that changes in the COOH terminus affect ion binding to the outer part of the pore. This effect correlated with the sensitivity to inactivation by H+. We conclude that decreasing pHI increases the sensitivity of ROMK2 channels to K+o by altering the properties of the selectivity filter.
Comparative investigation of two rotary nickel–titanium instruments: ProTaper versus RaCe. Part 2. Cleaning effectiveness and shaping ability in severely curved root canals of extracted teeth
Authors: Schäfer E. , Vlassis M.
Published: March 2004

Aim  To determine the cleaning effectiveness and shaping ability of ProTaper and RaCe nickel–titanium rotary instruments during the preparation of curved root canals in extracted human teeth.

Methodology  A total of 48 root canals of mandibular and maxillary molars with curvatures ranging between 25° and 35° were divided into two groups of 24 canals each. Based on radiographs taken prior to instrumentation with the initial instrument inserted into the canal, the groups were balanced with respect to the angle and the radius of canal curvature. Canals were prepared using a crown‐down preparation technique. After each instrument, the root canals were flushed with a 2.5% NaOCl solution and at the end of instrumentation with NaCl. Using pre‐ and post‐instrumentation radiographs, straightening of the canal curvatures was determined with a computer image analysis program. After splitting the roots longitudinally, the amount of debris and smear layer was quantified on the basis of a numerical evaluation scale, using a scanning electron microscope (SEM). The data established for scoring the debris and the smear layer were separately recorded and analysed statistically using the Wilcoxon test.

Results  Two ProTaper and three RaCe instruments fractured; there was no significant difference between instrument types (P > 0.05). Completely clean root canals were never observed. For debris removal, RaCe files achieved significantly better results (P < 0.001) than ProTaper instruments. The results for remaining smear layer were similar and not significantly different (P > 0.05). RaCe instruments maintained the original canal curvature significantly better (P < 0.05) than ProTaper instruments. No significant differences were detected between the instruments (P > 0.05) for the time taken to prepare the canals.

Conclusions  Under the conditions of this study, RaCe instruments resulted in relatively good cleaning and maintained the original curvature significantly better than ProTaper did.
A comparison of instrument‐centering ability within the root canal for three contemporary instrumentation techniques
Authors: Song Y. L. , Bian Z. , Fan B. , Fan M. W. , Gutmann J. L. , Peng B.
Published: March 2004

Aim  To study and compare Great Taper (GT) hand files using a reversed balanced force technique, nickel–titanium (NiTi)flex files with a balanced force technique and stainless steel (SS) K‐type files using a step‐back technique.

Methodology  Forty‐eight extracted mandibular premolar teeth with single root canals having curvatures between 15 and 45° were prepared using a modified Bramante model and randomly divided into three groups. The teeth were cross‐sectioned at 2, 6 and 10 mm from the working length. Preoperative images of canals at three levels were captured at 20× magnification using a stereomicroscope. Canals in each group were, respectively, prepared to an apical size .10 GT file with 0.2 mm tip diameter, size 30 NiTiflex file and size 30 SS K‐file. The GT file was used in a reversed balanced force technique, the NiTiflex file was used in a balanced force technique, and the SS K‐file was used in a step‐back technique. Postoperative canals were imaged under the conditions same as those for the preoperative canals. The postoperative images were superimposed over the preoperative images using software photoshop 6.0. The ability to maintain the instrument in the central axis of the canal and the deviation from the central canal axis were determined and compared by statistical analysis, along with the assessment of the amount of dentine removed.

Results  At apical level, the centering ratio, the distance of transportation and the dentine removed in GT and NiTiflex groups were significantly less than those in SS group (P < 0.01), but no statistical differences were found between the two NiTi groups. At other levels, there were no substantial differences amongst the groups.

Conclusions  Compared with SS K‐files, GT hand files and NiTiflex files remain better centered and produce significantly less transportation in curved canals.
Toxicity of concentrated sodium hypochlorite used as an endodontic irrigant
Authors: Gernhardt C. R. , Eppendorf K. , Kozlowski A. , Brandt M.
Published: March 2004

Aim  To present a clinical case that illustrates the toxicity of concentrated sodium hypochlorite (NaOCl) on vital tissues.

Summary  The severe clinical consequences of extruding concentrated NaOCl into the periradicular tissues during root canal irrigation are described. After diagnosis of external resorption in tooth 34, endodontic treatment was initiated. Following irrigation with a concentrated NaOCl solution, a rapidly developing swelling and haematoma were visible. During the next few days, an extensive bruise and local necrosis of the oral mucosa developed. After healing of the involved tissues, the canal was prepared and obturated. At this time, no clinical symptoms remained.

Key learning points

The use of concentrated NaOCl as a root canal irrigant might cause severe clinical problems when extruded into vital tissues.

The present report confirms the known toxicity of NaOCl to soft tissues following inadvertent extrusion.

To avoid extrusion, it is always prudent to confirm the length and integrity of the root canal system before irrigating with concentrated solutions.
Role of Keratinocytes in Antigen Presentation and Polarization of Human T Lymphocytes
Authors: Banerjee G. , Damodaran A. , Devi N. , Dharmalingam K. , Raman G.
Published: March 2004

Allergic contact dermatitis is a T‐cell‐mediated inflammatory skin disease in which interaction between skin keratinocytes and migrating T lymphocytes may play a critical part. In this study, the role of keratinocytes as allergen‐/antigen‐presenting cells (APCs) leading to activation of T lymphocytes is investigated using a human epidermal cell line A431. It is known that cultured cells do not express human leucocyte antigen (HLA) and hence can be used as APCs independent of HLA profile of both APCs and T cells from human volunteers. This cell line responded to common allergens and irritants by inducing or upregulating the cell‐surface expression of HLA‐DR, and intercellular adhesion molecule‐1 and B7 mRNA transcripts in keratinocytes. In addition, allergen‐primed A431 cells also induced allergen‐specific proliferation of human T lymphocytes in cocultures. Anti‐HLA‐DR, interleukin‐1α (IL‐1α) antibodies and lysosomotropic agent chloroquine inhibited the proliferation. Allergens also upregulated cytokines IL‐1α, granulocyte–macrophage colony‐stimulating factor, Gro‐α and IL‐12 in keratinocytes. Further, keratinocytes activated by allergens induced polarization of activated T lymphocytes to the Th1 phenotype.
DAILY HEMODIALYSIS—SELECTED TOPICS: Quantifying Daily Hemodialysis
Authors: Depner Thomas A. , Bhat Adarsh
Published: March 2004

Nearly all published reports and clinical studies of hemodialysis solute kinetics are confined to thrice‐weekly dialysis schedules. Over the past 40 years, clinical experience with dialysis treatments given three times per week has expanded enormously, but it was not until the Hemodialysis (HEMO) study results were revealed that nephrologists became fully aware of the limits of usefulness of infrequent dialysis. In light of continued reports of improved quality of life and survival with daily dialysis, it appears that the limits of thrice‐weekly dialysis may be extended when treatments are given more often. Analysis of solute kinetics during and between dialyses supports the notion that a more frequent schedule delivers more efficient dialysis and that methods can be developed to allow a comparison of risks among patients treated 3–7 days per week. One such method, based on the concept of solute seclusion, suggests that at the currently established minimum standard dose, approximately 50% of the improvement in solute control afforded by seven treatments per week is achieved by increasing the frequency to four treatments per week. The same model shows that seven treatments per week afford an improvement in solute control that is approximately 80% as effective as continuous dialysis. These conclusions are similar to those derived from a completely different model based on peak concentration toxicity. Neither of these models has been clinically tested, so caution must be advised when treating individual patients.
DAILY HEMODIALYSIS—SELECTED TOPICS: Quality of Life and Daily Hemodialysis
Authors: Kutner Nancy G.
Published: March 2004

Preliminary findings indicate that daily hemodialysis positively impacts patients’ energy/fatigue and other uremic and intradialytic symptoms. In addition to improvements in perceived symptoms, improvements in patients’ perceived physical and psychosocial functioning have been reported. These findings have come from small series of patients, however, and may reflect an increased attention effect. Confirmation of preliminary findings and identification of changes in other quality of life outcomes await an adequately powered randomized clinical trial. Sleep quality, sexual functioning, and cognitive functioning are quality of life dimensions that may be impacted by daily hemodialysis but about which there is limited information in the preliminary data that exist. Understanding relationships among different levels of quality of life outcomes associated with daily hemodialysis requires consideration of emotional and psychological variables such as burden, depression, and satisfaction with care that may intervene between treatment and the quality of life outcomes that patients report. Deriving health utilities relevant to patient experience on different daily hemodialysis therapies, analyzing longitudinal quality of life outcomes reported by patients on daily hemodialysis, and investigating the effectiveness of daily hemodialysis for specific patient subgroups are research agendas that can provide information needed to facilitate treatment decision making in which quality of life has an important role.
DAILY HEMODIALYSIS—SELECTED TOPICS: Cardiovascular Effects of Frequent Intensive Hemodialysis
Authors: Chan Christopher T.
Published: March 2004

Cardiovascular disease remains the leading cause of morbidity and mortality for patients with end‐stage renal disease (ESRD). Frequent intensive hemodialysis (short daily hemodialysis [2 hours per session, six sessions per week] and nocturnal home hemodialysis [6 hours per session, five to six sessions per week]) has recently gained increasing popularity as an alternative to conventional hemodialysis (4 hours per session, three sessions per week). There is an emerging body of evidence that frequent intensive hemodialysis offers superior uremic toxin clearance, blood pressure control, and other cardiovascular outcomes. The goals of the present review are to systematically evaluate the available evidence in blood pressure control and cardiovascular outcomes in ESRD and the achievable changes after converting from conventional dialysis to frequent intensive hemodialysis, and to provide possible physiological explanations to account for these important changes of potent markers of adverse events in this patient population.
DAILY HEMODIALYSIS—SELECTED TOPICS: Predicting Treatment Dose for Novel Therapies Using Urea Standard Kt/V
Authors: Leypoldt John K. , Jaber Bertrand L. , Zimmerman Deborah L.
Published: March 2004

Calculation of urea standard Kt/V (stdKt/V) as a dose measure for guiding novel hemodialysis or hemofiltration therapy prescription is complex since this parameter depends on the magnitude of posttreatment urea rebound. We propose here a two‐step procedure for calculating urea stdKt/V from single‐pool urea Kt/V values (spKt/V) determined from serum urea concentrations in pretreatment and posttreatment blood samples. First, the dependence of urea stdKt/V on equilibrated Kt/V (eKt/V) was derived from a fixed‐volume single‐pool model. Second, an empirical equation for predicting urea eKt/V from urea spKt/V values was determined using multiple linear regression and available data during 4‐hour hemodialysis, 2‐hour hemodialysis, and 2‐hour hemofiltration treatments. This empirical (rate/dose) equation is likely more robust for novel therapies than other equations derived from only data during conventional (4‐hour) hemodialysis treatments. The combination of these formulas allowed construction of nomograms for calculating urea stdKt/V from spKt/V during novel therapies. These principles were further illustrated by calculating the predicted treatment dose for daily (six times per week) hemofiltration therapy required to achieve a given urea stdKt/V.
Stress‐ as Well as Suckling‐Induced Prolactin Release is Blocked by a Structural Analogue of the Putative Hypophysiotrophic Prolactin‐Releasing Factor, Salsolinol
Authors: Bodnár I. , Mravec B. , Kubovcakova L. , Tóth E. B. , Fülöp F. , Fekete M. I. K. , Kvetnansky R. , Nagy G. M.
Published: March 2004

Prolactin is secreted from the anterior lobe of the pituitary gland in response both to suckling and to stress. We recently observed that 1‐methyl‐6,7‐dihydroxy‐1,2,3,4‐tetrahydroisoquinoline (salsolinol), produced in the neurointermediate lobe of the pituitary gland, as well as in the medial basal hypothalamus, can selectively release prolactin from the anterior pituitary. Therefore, it has been proposed that salsolinol is a putative endogenous prolactin‐releasing factor (PRF). Here, we report that one structural analogue of salsolinol, 1‐methyl‐3,4‐dihydroisoquinoline (1MeDIQ), can block salsolinol‐induced release of prolactin, but does not affect prolactin release in response to thyrotropin releasing hormone (TRH), α‐methyl‐p‐tyrosine (αMpT) (an inhibitor of tyrosine hydroxylase), domperidone (a D2 dopamine receptor antagonist), or 5‐hydroxytryptophan (5‐HTP), a precursor of serotonin). 1MeDIQ profoundly inhibited suckling‐, immobilization‐, as well as formalin‐stress induced prolactin release without any influence on corticosterone secretion. The 1MeDIQ‐induced reduction in prolactin response to immobilization stress was dose‐dependent. These results suggest that salsolinol can play a pivotal role in the regulation of prolactin release induced by either physiological (suckling) or environmental (stress) stimuli.
Automatic Brains—Interpretive Minds
Authors: Roser Matthew , Gazzaniga Michael S.
Published: March 2004

The involvement of specific brain areas in carrying out specific tasks has been increasingly well documented over the past decade. Many of these processes are highly automatic and take place outside of conscious awareness. Conscious experience, however, seems unitary and must involve integration between distributed processes. This article presents the argument that this integration occurs in a constructive and interpretive manner and that increasingly complex representations emerge from the integration of modular processes. At the highest levels of consciousness, a personal narrative is constructed. This narrative makes sense of the brain's own behavior and may underlie the sense of a unitary self. The challenge for the future is to identify the relationships between patterns of brain activity and conscious awareness and to delineate the neural mechanisms whereby the underlying distributed processes interact.
Sources of Implicit Attitudes
Authors: Rudman Laurie A.
Published: March 2004

Response latency measures have yielded an explosion of interest in implicit attitudes. Less forthcoming have been theoretical explanations for why they often differ from explicit (self-reported) attitudes. Theorized differences in the sources of implicit and explicit attitudes are discussed, and evidence consistent with each theory is presented. The hypothesized causal influences on attitudes include early (even preverbal) experiences, affective experiences, cultural biases, and cognitive consistency principles. Each may influence implicit attitudes more than explicit attitudes, underscoring their conceptual distinction.
Moving Personality Beyond the Person-Situation Debate
Authors: Fleeson William
Published: March 2004

The person-situation debate is coming to an end because both sides of the debate have turned out to be right. With respect to momentary behaviors, the situation side is right: Traits do not predict, describe, or influence behavior very strongly; the typical individual's behavior is highly variable; and a process approach is needed to explain that variability. With respect to trends (e.g., a person's typical way of acting), however, the person side of the debate is right: Traits predict and describe behavior very well over long stretches of time, behavior is highly stable, and a trait approach is needed to explain differences between people. Thus, proponents of both sides are right and should continue to conduct fruitful research, and both viewpoints are necessary for a full understanding of personality. The next exciting steps in personality psychology will include integrating these two approaches in the same research paradigm.
Determination of factors influencing stomach content retention by striped bass captured using gillnets
Authors: Sutton T. M. , Cyterski M. J. , Ney J. J. , Duval M. C.
Published: March 2004

The influence of mode of capture, season of capture and total body length (LT) on the probability of regurgitation for striped bass Morone saxatilis captured using gillnets in Smith Mountain Lake, Virginia, was examined. Overall, the mean rate of regurgitation for striped bass which contained food contents in their stomach was 8·3%. Striped bass captured by wedging had a higher mean regurgitation rate (17%) than individuals that were either entangled (5%) or gilled (2%). Striped bass caught during the autumn had approximately the same frequency of regurgitation as individuals captured during the summer (10 v. 9%), but these regurgitation rates were higher than those observed for fish during the spring sampling periods (4%). Larger striped bass were more likely to regurgitate their stomach contents than smaller individuals, with the frequency of regurgitation increasing by 0·7% for every 50 mm increase in LT. The results of this study demonstrate the importance of identifying factors that influence regurgitation of stomach contents to minimize and account for biases associated with diet data collected from striped bass captured in gillnets. Using this information, sampling recommendations for food‐habit and feeding‐rate studies involving the collection of piscivorous fishes using gillnets are made.
Effects of abrupt cold shock on stress responses and recovery in brown trout exhausted by swimming
Authors: Hyvärinen P. , Heinimaa S. , Rita H.
Published: March 2004

To simulate swimming in a trawl, age 3 year brown trout Salmo trutta(L.) were made to swim against a flow of 0·5 m s−1 for 60 min. To simulate cold shock, similar to placing them in a chilling tank, the fish were kept for 10 min in a tank containing ice and water. To simulate the combined stressors, the fish were first made to swim followed by a cold shock. The fish were in a comatose state 10 min after cold shock and combined stressors but conscious after swimming only. All the fish survived until the end of the studied recovery period (maximum 24 h). Cold shock after swimming (combined stressors v. swimming only) did not produce higher blood cortisol, lactate or glucose concentrations 10 min after the treatment. The effect of cold shock, however, was evident in the delayed start of recovery in cortisol and glucose concentrations. All the stress indicators used decreased to the levels for undisturbed fish within 24 h, except in the case of glucose after the combined stressors.
Anaemia and salmonid swimming performance: the potential effects of sub‐lethal sea lice infection
Authors: Wagner G. N. , Mckinley R. S.
Published: March 2004

The effect of two known rates of repeated blood loss on rainbow trout Oncorhynchus mykiss swimming performance was measured and blood‐feeding rates of sea lice Lepeophtheirus salmonis were calculated to predict the point at which blood ingestion causes anaemia in infected fish. Known quantities of blood were sampled from rainbow trout over a 5 day period followed by critical swimming performance (Ucrit) testing. A predictive equation was developed using masses of blood‐feeding sea lice and host blood loss calculated for increasing levels of sea lice infection. Blood loss of 8% total blood volume caused a decrease in Ucrit for rainbow trout. Total blood volume losses of 3·2% reduced erythrocyte stores, but did not affect fish swimming performance. The predictive feeding rate model suggests that 15–25% of the tissue consumed by sea lice is blood. This consumption of blood at higher sub‐lethal infection levels (≥0·5 sea lice g−1) may cause anaemia and a further decrease in swimming performance. Anaemia would compound the osmotic balance problems due to infection and potentially precipitate the morbidity seen at lethal sea lice levels (0·75–1·0 lice g−1).
Somatostatin is a specific inhibitor of SDF-1α-induced T cell infiltration
Authors: TALME T , IVANOFF J , SUNDQVIST K G
Published: March 2004

The chemokine stromal cell-derived factor 1α (SDF-1α) is a potent stimulator of T cell infiltration into three-dimensional type I collagen matrices as demonstrated using T cells freshly isolated from blood and an activated T cell clone. The neuropeptide somatostatin selectively inhibits SDF-1α induced T cell infiltration by the same T cells including CD4 as well as CD8 positive cells, while somatostatin does not inhibit ‘spontaneous’ T cell infiltration. A number of other neuropeptides and opioids do not inhibit SDF-1α-induced T cell infiltration, indicating that the inhibitory effect is somatostatin-specific. The neuropeptide antagonist cyclosomatostatin abrogated the inhibitory effect of somatostatin on T cell infiltration, indicating that the effect of somatostatin is mediated via specific somatostatin receptors. Somatostatin does not inhibit SDF-1α-induced T cell attachment to the collagen substrate, which indicates that this neuropeptide specifically inhibits the process of chemokine-induced T cell penetration and migration through the collagen.
Australian long‐tailed gall thrips (Thysanoptera: Phlaeothripinae, Leeuweniini), with comments on related Old World taxa
Authors: Mound Laurence A
Published: March 2004

Abstract  The Tribe Leeuweniini is a group of Old World Phlaeothripinae species that feed and usually induce irregular galls on the leaves of rainforest trees. These thrips all have the last abdominal segment unusually elongate, but this is a variable and homoplastic character state, and the tribe remains ill‐defined. Worldwide, 27 species in three genera are now recognised, with five other generic names here included as synonyms of Leeuwenia Karny. From Australia, six species in two genera are recorded here occurring in the eastern rainforests. Four newly described Australian species and their host plants are: Leeuwenia diospyri sp. n. (Diospyros pentamera–Ebenaceae); L. polyosmae sp. n. (Polyosma cunninghamii–Grossulariaceae); L. scolopiae sp. n. (Scolopia braunii–Flacourtiaceae); and L. tetrastigmae sp. n. (Tetrastigma nitens–Vitaceae). The host association of L. convergens Hood is not known, but the sixth species, Neohoodiella jennibeardae Mound and Williams, breeds on two unrelated plants of which the leaves are similar in texture –Ficus coronata (Moraceae) and Rhipogonum elseyanum (Smilacaceae).
Social Change, Values and Political Agency: The Case of the Third Way
Authors: Leggett Will
Published: March 2004

The third way is based on both sociological claims about a changed world, and normative propositions about appropriate conduct within that world. Four types of claim concerning the relationship between social change and political values are identified within third way advocacy. In each case, the degree of political agency implied is assessed. This ranges from a position which minimises the room for political interventions in the face of social change, to one which gives primacy to the role of political values. A successful third way project, or alternative, needs not only to be grounded in contemporary social change, but also to show how to steer it.
A method for exact reliability of consecutive2‐out‐of‐(r, r)‐from‐(n, n):F systems
Authors: Higashiyama Y.
Published: March 2004

A new reliability model, consecutive 2‐out‐of‐(r, r)‐from‐(n, n):F model, is proposed. The consecutive 2‐out‐of‐(r, r)‐from‐(n, n):F system consists of a square grid of side n (containing n2 components) such that the system fails if and only if there is at least one square of side r which includes among them at least two failed components. For i.i.d. case an algorithm is given for computing the reliability of the system. The reliability function can be expressed by the number of 0–1 matrices having no two or more 0s at any square of side r.
Effect of Modified Ultrafiltration on Inflammatory Mediators, Coagulation Factors, and Other Proteins in Blood after an Extracorporeal Circuit
Authors: Fujita Masanori , Ishihara Masayuki , Kusama Yoshimasa , Shimizu Masafumi , Kimura Tamizo , Iizuka Yasuhiro , Ozaki Shigeyuki , Muraoka Masato , Morimoto Yuji , Takeshima Shigeto , Kikuchi Makoto , Maehara Tadaaki
Published: March 2004

Abstract:  Modified ultrafiltration (MUF) is a technique able to remove the excess body fluid and inflammatory mediators associated with the use of a cardiopulmonary bypass (CPB). It has been shown to reduce morbidity after cardiac operations in children. Application of MUF after adult cardiac operations has also been suggested being associated with a lower prevalence of early morbidity. However, the relationship between the concentration of mediators in the blood and postoperative morbidity remains yet to be proved. In this study, changes of various chemical mediators in the filtrate and blood before and after MUF have been evaluated in adult patients. Significant reductions of blood levels of inflammatory cytokines were not observed after MUF. On the other hand, MUF significantly elevated hematocrit, number of red cells, concentrations of albumine, coagulation Factor VII and X, platelet factor (PF)‐4, and antithrombin (AT‐) III.