bluuebunny/crossref_metadata_2025 huggingface dataset:
Polyelectrolyte adsorption and multilayering on charged colloidal particles
Authors: Messina René , Holm Christian , Kremer Kurt
Published: August 2004

In this article we review the complexation behavior of charged polymers adsorbed onto charged substrates. In the first part we summarize the results obtained on the adsorption properties of a single polyelectrolyte chain with one or several oppositely charged spherical colloids. The results of various simulational studies are compared with theoretical predictions. After that, we show that under strong electrostatic coupling conditions one can also obtain complexations, where chain and colloid carry the same charge (like‐charge complexation). This effect is due to counterion correlation effects. Finally, we investigate the case of polyelectrolyte multilayers structures, which are composed of alternating polycations and polyanions on various substrate geometries. This structure, normally obtained by a so‐called layer‐by‐lay deposition, is very stable experimentally, but only poorly understood in terms of theoretical approaches. Our simulation results suggest that short range attractive interactions (e.g., van der Waals) are important for obtaining a stable sequence of multilayers. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3557–3570, 2004
Polyelectrolyte‐mediated bridging interactions
Authors: Podgornik Rudi
Published: August 2004

Polyelectrolyte chains confined by macroions bearing electrostatic charges of opposite sign can mediate an effective attraction between the macroions. This polyelectrolyte‐mediated attraction is usually referred to as the bridging interaction. I review the theories of polyelectrolyte‐mediated interactions based on analytic mean‐field and variational approaches. I will describe the origin and the salient properties of this interaction in the context of planar and point macroions with special emphasis on the connection between the polymer chain conformations and the ensuing polymer mediated interactions. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3539–3556, 2004
Comment on the dynamic bead size and Kuhn segment length in polymers: Example of polystyrene
Authors: Ding Y. , Sokolov A. P.
Published: August 2004

Discrepancies between the length of a traditionally defined Kuhn segment length (lk) and a bead size estimated from experimental data have been reported in a number of articles. In this work we emphasize that the traditional definition of the Kuhn segment is an oversimplification and the characteristic ratio, C∞, is not the only parameter that defines a bead size. We show that the dynamic bead size in polystyrene (PS) might be as large as ∼50 monomers, whereas the traditionally defined Kuhn segment is ∼8–10 monomers. It is shown that with 50 monomers (M ∼ 5000) as a size of the dynamic bead, one can explain many inconsistencies in the interpretation of compliance and mechanical relaxation data known for low‐molecular weight PS. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3505–3511, 2004
Mössbauer effect studies of disordered Fe–Ru alloys
Authors: Pöttker W. E. , Paduani C. , Ardisson J. D. , Ioshida M. I.
Published: August 2004

The bcc and hcp phases of disordered Fe100–xRux alloys are investigated with several experimental techniques to study the composition dependence of the magnetic properties in these structures. With an appropriate annealing the prepared samples are single phase. The iron rich alloys are ferromagnetic at room temperature with the bcc structure. However, an antiferromagnetic coupling is introduced with the addition of ruthenium. Above 30 at% Ru a paramagnetic behavior is observed at 300 K and 77 K, where the alloys have the hcp structure. In the ferromagnetic phase the Curie temperature decreases steadly with the increase of the ruthenium concentration. In the paramagnetic hcp phase the mean volume per atom is al‐most triplicated as compared to the bcc phase, which brings out the breakdown of the magnetization and the collapse of the hyperfine field at the iron sites simultaneously with the crystallographic phase transition. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structural study of ferroelectric and paraelectric phases in PbK2LiNb5O15
Authors: Gagou Y. , Muller Ch. , Frémy M.‐A. , Mezzane D. , Elkaïm E. , Saint‐Grégoire P.
Published: August 2004

The structures of PbK2LiNb5O15 showing the ferroelectricity below about 640 K have been studied in the paraelectric and ferroelectric phases by means of synchrotron X‐ray powder diffraction. The data are analyzed with a Rietveld refinement method. It is found that the paraelectric structure and the ferroelectric one are of tetragonal and orthorhombic symmetry with P4/mbm and Pba2, respectively. The Pba2 structure gives a polar displacement along c‐axis, whose direction is consistent with that deduced from dielectric measurements. The refined chemical occupancies of the cations Pb, K and Nb give the site‐situation of these ions in the tunnels with square sections and pentagonal sections in each phase. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Orbital ordering and orbital fluctuations in transition metal oxides [phys. stat. sol. (b) 236, No. 2, 281–288 (2003)]
Authors: Oleś Andrzej M.
Published: August 2004

The labeling of Fig. 1(b) has to be corrected.

See original phys. stat. sol. (b) 236, No. 2, 281–288 (2003)
Structural study of ferroelectric and paraelectric phases in PbK2LiNb5O15
Authors: Gagou Y. , Muller Ch. , Frémy M.‐A. , Mezzane D. , Elkaïm E. , Saint‐Grégoire P.
Published: August 2004

The cover picture of the present issue of physica status solidi (b) is a Fourier map calculated from the Pba2 space group, which corresponds to the ferroelectric structure of PbK2LiNb5O15. It was revealed by synchrotron X‐ray powder diffraction investigations reported in the paper [1]. Positions of the various Pb, K, and O atoms in the unit cell are indicated by the labels.
Pathology raw data in nonclinical laboratory studies for the pharmaceutical industry: The pathologists' view
Authors: Geoly Frank J. , Kerlin Roy L.
Published: August 2004

Post‐mortem pathology data from nonclinical laboratory studies contain critical information for characterizing a new drug's safety and are pivotal for gaining an appreciation of potential hazards to humans. An understanding of the historical regulatory and scientific perspective on the nature of pathology data is valuable for assuring appropriate and useful audits of pathology material within nonclinical studies. This discussion reviews the specialty of pathology, the process of medical diagnosis, the definitions of ‘raw data’ as they pertain to histopathology data, and the rationale behind the consensus decisions made by industry and the Food and Drug Administration (FDA) in interpreting good laboratory practice (GLP) regulations for this type of data. Copyright © 2004 John Wiley & Sons, Ltd.
Ethical considerations in clinical trials
Authors: Whalen Matthew , Khin‐Maung‐Gyi Felix , Wambolt Ann L.
Published: August 2004

Ethics is no longer the privileged domain of a few academicians, nor of Institutional Review Boards/Ethics Review Committees (IRBs/ERCs) overseeing clinical trials. Ethical considerations impacting multiple aspects of the conduct of research are central to clinical research. As a result, there are ethical dimensions to every aspect of clinical research. This article results from a session at the 2003 Society of Quality Assurance (SQA) Annual Meeting in Washington, DC, USA. This summary of the ethical and public policy‐related underpinnings for our comments during the session should benefit those who were unable to attend the session as well as to provide further perspectives for those who participated in the discussion. Copyright © 2004 John Wiley & Sons, Ltd.
Science and Quality Assurance: From dose to overdose
Authors: Jones Anthony B.
Published: August 2004

For Quality Assurance to be a proactive partner in drug development we need to understand the scientific concepts that define and shape the pharmaceutical process. Drug development can be more easily understood by considering the basic scientific principles governing the numerous scientific disciplines that contribute to producing safe and effective drugs. This article describes how two of these principles influence drug development from choice of molecule through to clinical testing and how they interact with FDA regulations and Quality Assurance. Copyright © 2004 John Wiley & Sons, Ltd.
What's new?
Authors: Broughton Harold Steven , Hattemer‐Apostel Rita
Published: August 2004

The What's New? section in the Quality Assurance Journal aims to draw attention to items of importance to QA professionals. There is usually a three‐month interval between final submission of manuscripts and distribution of the journal. For this issue, the entries in the What's New? section arise from the period of 1 March 2004 to 31 May 2004. If you feel that there is any other new information that should be brought to the attention of readers, please let us know by e‐mailing rha@verdandi.ch. Copyright © 2004 John Wiley & Sons, Ltd.
Why has feedback systems thinking struggled to influence strategy and policy formulation? Suggestive evidence, explanations and solutions
Authors: Warren Kim
Published: August 2004

Proponents of system dynamics expound its benefits for understanding and managing complex social systems. However, usage of system dynamics remains low, which questions the true value that policy‐makers gain from the approach as currently delivered. Feedback systems thinking and causal loop diagrams currently dominate the representation of problem situations. Although substantial benefits are claimed for this approach, it embeds serious theoretical and pedagogical flaws, notably by separating the problem behaviour from the structure alleged to cause it, by ignoring scale and timing of behaviour, and by excluding the fundamental and unavoidable properties of asset stock accumulation. Policy‐makers are thus unlikely to be provided with actionable solutions, whether from feedback diagrams alone or from subsequent simulation models, a failure that may have irretrievably alienated a significant fraction of management who have been exposed to system dynamics. Copyright © 2004 John Wiley & Sons, Ltd.
The relationship between performance in dynamic systems and intelligence
Authors: Wittmann Werner W. , Hattrup Keith
Published: August 2004

System dynamics is a field that emphasizes the complex demands on human decision‐makers and the cognitive processes that are either wired into the brain by nature or by education or that are stimulated by nurture. The world can be regarded as a complex system and it is a fascinating question how the human brain has adapted to its complexity and survived. Of considerable interest are the human dispositions or characteristics that are responsible for survival and adaptation. Are individual differences in human ability, aptitude, personality, or knowledge the origin of failures and successes in complex environments? These constructs are at the center of much research in psychology and cognitive sciences. Much controversy has revolved around whether dispositions like intelligence or situational constraints and characteristics of the environment are the most important predictive and explanatory constructs. The present work describes recent psychological research on working memory, intelligence, and performance on complex tasks. This research shows that intelligence, combined with personality and interests, are indeed constructs of impressive power in predicting performance. Implications of this research for selecting, educating, and training managers and decision‐makers in charge of handling such complex systems are proposed and elaborated. Copyright © 2004 John Wiley & Sons, Ltd.
YIHn: A New Family of Metal‐rich Hydride Halides
Authors: Ryazanov Mikhail , Simon Arndt , Mattausch Hansjürgen
Published: August 2004

The graphite‐like yttrium hydride halides, YIHn (0.8 ⩽ n ⩽ 1.0), have been prepared in quantitative yields by heating either YI3, YH2 (1:2) or stoichiometric YI3, YH2, Y mixtures in sealed Ta ampoules at 900°C. A lower limit of the homogeneity range, n ≈ 2/3, has been determined from dehydrogenation experiments. All YIHn phases adopt the ZrBr‐type heavy‐atom structure. The hydrogen variation is accompanied by a change in the c lattice constant from 31.162(3) to 31.033(1) Å for n = 0.61(3) to 1.02(3). The YIHn phases reversibly react with hydrogen at 400‐600°C to form the light green transparent compound YIH2. However, increasing the reaction temperature above 700°C causes decomposition to an unidentified phase being in equilibrium with YH2 and YI3. The arrangement of the heavy atoms in YIH2 (P $\bar 3$m1; a = 3.8579(3) Å, c = 10.997(1) Å) corresponds to a four‐layer I‐Y‐Y‐I slab with the stacking sequence (AbaB) as was found by x‐ray powder diffraction data refinement with the Rietveld method. A miscibility gap exists between YIH and YIH2.

Samples YIHn (n ⩽ 1.0) show metallic conductivity at room temperature, which changes into semiconducting behavior with decreasing temperature as n approaches its lower value ≈ 2/3.
Synthesis and Structure of a Bipyridyldicarboxylate Connected Neodyminum Organic Framework
Authors: Schoknecht Birk , Kempe Rhett
Published: August 2004

The porous neodymium coordination polymer {[L3Nd2(H2O)4] (LH2 = 2,2′‐bipyridine‐5,5′‐dicarboxylic acid)} (1) was prepared via a hydrothermal synthesis approach starting from Nd(NO3)3·6H2O and 2,2′‐bipyridine‐5,5′‐dicarboxylic acid in a one to one mixture of ethanol and water at 160°C. The product was characterized by single crystal X‐ray diffraction, TGA and elemental analysis. Space group: P$\bar 1$, a: 6.0294(4), b: 10.9061(6), c: 13.8392(9) Å, α: 101.486(7), β: 93.799(8)°, γ: 100.933(7)°, R1 [> 2σ (I)] = 0.0147, wR2 (all data) = 0.0328. The structure determination revealed 1 to be a 3‐dimensional network with eight‐coordinated lanthanide centres acting as 5‐connectors and two types of bipyridyldicarboxylate cross‐linkers, as 3‐ and a 4‐connectors. After the loss of water – two per neodymium atom‐channels are formed with a channel diameter of 4.82 Å [atom to atom distances (Nd‐O)].
Nd2(SeO3)2(SeO4) · 2H2O – a Mixed‐Valence Compound containing Selenium in the Oxidation States +IV and +VI
Authors: Berdonosov P. S. , Schmidt P. , Dityat'yev O. A. , Dolgikh V. A. , Lightfoot P. , Ruck Michael
Published: August 2004

Pale pink crystals of Nd2(SeO3)2(SeO4) · 2H2O were synthesized under hydrothermal conditions from H2SeO3 and Nd2O3 at about 200 °C. X‐ray diffraction on powder and single‐crystals revealed that the compound crystallizes with the monoclinic space group C 2/c (a = 12.276(1) Å, b = 7.0783(5) Å, c = 13.329(1) Å, β = 104.276(7)°). The crystal structure of Nd2(SeO3)2(SeO4) · 2H2O is an ordered variant of the corresponding erbium compound. Eight oxygen atoms coordinate the NdIII atom in the shape of a bi‐capped trigonal prism. The oxygen atoms are part of pyramidal (SeIVO3)2− groups, (SeVIO4)2− tetrahedra and water molecules. The [NdO8] polyhedra share edges to form chains oriented along [010]. The selenate ions link these chains into layers parallel to (001). The layers are interconnected by the selenite ions into a three‐dimensional framework. The dehydration of Nd2(SeO3)2(SeO4) · 2H2O starts at 260 °C. The thermal decomposition into Nd2SeO5, SeO2 and O2 at 680 °C is followed by further loss of SeO2 leaving cubic Nd2O3.
A Novel One‐Dimensional Zinc Coordination Polymer, [Zinc{(4,5‐ditetrazoyl)‐imidazole}{(1,10)‐phenanthroline}(H2O)]n
Authors: Zhao Hong , Ye Qiong , Wu Qian , Song Yu‐Mei , Liu Yu‐Juan , Xiong Ren‐Gen
Published: August 2004

The reaction of 4,5‐dicyanoimidazole with ZnCl2 and NaN3 in the presence of (1,10)‐phenanthroline and water affords a novel one‐dimensional zinc coordination polymer, [zinc{(4,5‐ditetrazoyl)‐imidazole}{(1,10)‐phenanthroline}(H2O)]n (1), in which 1 contains a ditetrazole ligand and strongly supports the Demko‐Sharpless' tetrazole synthesis reaction. The structure was determined by single crystal X‐ray diffraction. Crystal data: P21/n; a = 11.908(18); b = 8.133(10); c = 21.01(3) Å; β = 112.46(7)°; V = 1880(1) Å3; Z = 4; R1 = 0.0882, wR2 = 0.2091.
Er2S[SiO4]: Ein Erbiumsulfid‐ortho‐Oxosilicat mit ungewöhnlicher Sulfidionen‐Koordination
Authors: Hartenbach Ingo , Lauxmann Petra , Schleid Thomas
Published: August 2004

Bei der Umsetzung von Cadmiumsulfid mit den Elementen Erbium und Schwefel in evakuierten Kieselglasampullen fallen als Nebenprodukt stäbchenförmige, rosafarbene Kristalle von Er2S[SiO4] an, welche durch Einkristallstrukturanalyse charakterisiert wurden. Die Titelverbindung kristallisiert orthorhombisch in der Raumgruppe Cmce (a = 1070,02(8), b = 1235,48(9), c = 683,64(6) pm) mit acht Formeleinheiten in der Elementarzelle. Die Kristallstruktur enthält neben isolierten ortho‐Oxosilicat‐Einheiten [SiO4]4− zwei kristallographisch unterschiedliche Er3+‐Kationen, die beide achtfach von sechs Sauerstoff‐ und zwei Schwefelatomen koordiniert sind. Die Sulfid‐Anionen werden ihrerseits von vier Er3+‐Kationen sehr verzerrt tetraedrisch umgeben. Diese exzentrischen [SEr4]10+‐Tetraeder bilden durch Ecken‐ und Kantenverknüpfung Schichten gemäß $^{2}_{\infty}{[{\rm SEr}_{4/2}]}^{4+}$ aus, die parallel (010) verlaufen und zwischen denen sich die isolierten ortho‐Oxosilicat‐Tetraeder anordnen.
Synthese und Kristallstrukturen von heteronuklearen AgI/FeII‐Koordinationspolymeren: (Me3PhN)2[Ag2Fe(SCN)6], (Me3PhN)6[Ag6Fe3(ECN)18] (E = S, Se) und (Me3PhN)4[Ag2Fe(SCN)8]
Authors: Gerber Stefan , Krautscheid Harald , Gelbrich Thomas , Vollmer Heike
Published: August 2004

Bei der Reaktion von AgSCN mit (Me3PhN)3[Fe(NCS)6] in DMF bilden sich die SCN−‐verbrückten, zweidimensional polymeren, heteronuklaren Komplexe (Me3PhN)2[Ag2Fe(SCN)6] (1) und (Me3PhN)6[Ag6Fe3(SCN)18]·CH2Cl2·DMF (2a), während bei Zugabe von (Me3PhN)(SCN) zur Reaktionslösung der kettenförmige Komplex (Me3PhN)4[Ag2Fe(SCN)8] (3) entsteht. Die zu 2a homologe Selenocyanatverbindung 2b konnte ebenfalls erhalten werden. Die Einkristall‐Röntgenstrukturanalysen zeigen, dass die Ag+‐Ionen in 1 und 2a tetraedrisch von vier S‐Atomen, in 3 von einem N‐ und drei S‐Atomen der verbrückenden SCN−‐Liganden koordiniert sind, an die Fe2+‐Ionen binden die SCN−‐ bzw. SeCN−‐Liganden stets über die N‐Atome in oktaedrischer Anordnung.
Health related quality of life and quantitative pain measurement in females with chronic non‐malignant pain
Authors: Laursen Birgitte S. , Bajaj Priti , Olesen Anders S. , Delmar Charlotte , Arendt‐Nielsen Lars
Published: August 2004

The aim of the present study was to assess, compare, and correlate the pain response to an experimental pain stimulus (hyperalgesia to pressure pain threshold (PPT) measured from different body sites), the pain intensity (VAS) of the habitual pain, and quality of life parameters (SF‐36) in groups of females with chronic non‐malignant pain syndromes. Forty female pain patients with fibromyalgia/whiplash (n = 10), endometriosis (n = 10), low back pain (n = 10), or rheumatoid arthritis (n = 10), as well as 41 age‐matched healthy female controls participated in the study.

The fibromyalgia/whiplash patients scored significantly higher (p < 0.04) VAS ratings (median rating = 7.0) than the endometriosis (6.0), low back pain (6.0), and rheumatoid arthritis (3.5) patients. All fours patient groups had significantly lower PPTs at all sites as compared with controls.

The fibromyalgia/whiplash patients experienced the highest influence of pain on their overall health status, particularly vitality, social function, emotional problems, and mental health. A significant negative correlation was found between VAS rating and quality of life (p < 0.04). Significant correlation (p < 0.05) was found between pressure hyperalgesia measured at lowest PPT sites and the impairment of SF‐36 physical function as well as mental health parameters.

This study demonstrates significant generalised pressure hyperalgesia in four groups of chronic pain patients, correlations between degree of pressure hyperalgesia and impairment of some quality of life parameters, and increased pain intensity of the ongoing pain is associated with decreased quality of life.
Neurological soft signs in homicidal men with antisocial personality disorder
Authors: Lindberg Nina , Tani Pekka , Stenberg Jan-Henry , Appelberg Björn , Porkka-Heiskanen Tarja , Virkkunen Matti
Published: August 2004

Neurological soft signs (NSS) are characterized by abnormalities in motor, sensory, and integrative functions. NSS have been regarded as a result of neurodevelopmental dysfunction, and as evidence of a central nervous system defect, resulting in considerable sociopsychological dysfunction. During the last decade there has been growing evidence of brain dysfunction in severe aggressive behavior. As a symptom, aggression overlaps a number of psychiatric disorders, but it is commonly associated with antisocial personality disorder. The aim of the present study was to examine NSS in an adult criminal population using the scale by Rossi et al. [29]. Subjects comprised 14 homicidal men with antisocial personality disorder recruited from a forensic psychiatric examination. Ten age- and gender-matched healthy volunteers as well as eight patients with schizophrenia, but no history of physical aggression, served as controls. The NSS scores of antisocial offenders were significantly increased compared with those of the healthy controls, whereas no significant differences were observed between the scores of offenders and those of patients with schizophrenia. It can be speculated that NSS indicate a nonspecific vulnerability factor in several psychiatric syndromes, which are further influenced by a variety of genetic and environmental components. One of these syndromes may be antisocial personality disorder with severe aggression.
PD‐1 inhibits T‐cell receptor induced phosphorylation of the ZAP70/CD3ζ signalosome and downstream signaling to PKCθ
Authors: Sheppard Kelly-Ann , Fitz Lori J. , Lee Julie M. , Benander Christina , George Judith A. , Wooters Joe , Qiu Yongchang , Jussif Jason M. , Carter Laura L. , Wood Clive R. , Chaudhary Divya
Published: August 2004

Engagement of the immunoinhibitory receptor, programmed death‐1 (PD‐1) attenuates T‐cell receptor (TCR)‐mediated activation of IL‐2 production and T‐cell proliferation. Here, we demonstrate that PD‐1 modulation of T‐cell function involves inhibition of TCR‐mediated phosphorylation of ZAP70 and association with CD3ζ. In addition, PD‐1 signaling attenuates PKCθ activation loop phosphorylation in a cognate TCR signal. PKCθ has been shown to be required for T‐cell IL‐2 production. A phosphorylated PD‐1 peptide, corresponding to the C‐terminal immunoreceptor tyrosine‐switch motif (ITSM), acts as a docking site in vitro for both SHP‐2 and SHP‐1, while the phosphorylated peptide containing the N‐terminal PD‐1 immunoreceptor tyrosine based inhibitory motif (ITIM) associates only with SHP‐2.
Functional identification of AtFao3, a membrane bound long chain alcohol oxidase in Arabidopsis thaliana
Authors: Cheng Qi , Liu Huan-Ting , Bombelli Paolo , Smith Alison , Slabas Antoni R.
Published: August 2004

The Arabidopsis thalina genome database was searched for homologues of the Candida cloacae fao1 gene which encodes a membrane bound, flavin‐containing, hydrogen peroxide generating, long chain alcohol oxidase. This gene has not been isolated from plants or animals. Four putative candidates were found in the database but their function has not been proven. The cDNAs for two of them were cloned by RT‐PCR from Arabidopis suspension culture and one of them [AtFAO3] was overexpressed in Escherichia coli and shown to functionally express long chain alcohol oxidase activity. The protein has been solubilised and retains biological activity thereby preparing the way for crystallographic studies. This is the first functional proof identifying a long chain alcohol oxidase in higher plants.
Inhibition of membrane‐bound lytic transglycosylase B by NAG‐thiazoline
Authors: Reid C.W. , Blackburn N.T. , Legaree B.A. , Auzanneau F.-I. , Clarke A.J.
Published: August 2004

The lytic transglycosylases cleave the bacterial cell wall heteropolymer peptidoglycan with the same specificity as the muramidases (lysozymes), between the N‐acetylmuramic acid and N‐acetylglucosamine residues, with the concomitant formation of a 1,6‐anhydromuramoyl residue. The putative catalytic residue in the family 3 lytic transglycosylase from Pseudomonas aeruginosa, Glu162 as identified by sequence alignment to the homologous enzyme from Escherichia coli, was replaced with both Ala and Asp by site‐directed mutagenesis. Neither mutant enzyme differed structurally from the wild‐type enzyme, as judged by CD spectroscopy, but both were enzymatically inactive confirming the essential role of Glu162 in the mechanism of action of this lytic transglycosylase. The β‐hexosaminidase inhibitor NAG‐thiazoline was shown to inhibit the activity of lytic transglycosylase activity, thus providing the first direct evidence that the formation of the 1,6‐anhydromuramoyl residue may proceed through an oxazolinium ion intermediate involving anchimeric assistance. Using surface plasmon resonance and difference absorbance spectroscopy, K
d values of 1.8 and 1.4 mM, respectively, were determined for NAG thiazoline, while its parent compound N‐acetylglucosamine neither inhibited nor appeared to bind the lytic transglycosylase with any significant affinity.
Gene delivery of the elastase inhibitor elafin protects macrophages from neutrophil elastase‐mediated impairment of apoptotic cell recognition
Authors: Henriksen Peter A. , Devitt Andrew , Kotelevtsev Yuri , Sallenave Jean-Michel
Published: August 2004

The resolution of inflammation is dependent on recognition and phagocytic removal of apoptotic cells by macrophages. Receptors for apoptotic cells are sensitive to degradation by human neutrophil elastase (HNE). We show in the present study that HNE cleaves macrophage cell surface CD14 and in so doing, reduces phagocytic recognition of apoptotic lymphocytic cells (Mutu 1). Using an improved method of adenovirus‐mediated transfection of macrophages with the HNE inhibitor elafin, we demonstrate that elafin overexpression prevents CD14 cleavage and restores apoptotic cell recognition by macrophages. This approach of genetic modification of macrophages could be used to restore apoptotic cell recognition in inflammatory conditions.
Thermohaline effects of the seasonal sea ice cover in the Sea of Okhotsk
Authors: Watanabe Tatsuro , Ikeda Motoyoshi , Wakatsuchi Masaaki
Published: August 2004

By using a coupled ice‐ocean model, the seasonal extent of the sea ice cover in the Sea of Okhotsk was examined. The model results show that the sea ice at the ice edge is advected southward along Sakhalin Island with a mean velocity of 0.31m/s into ocean water with temperatures above freezing. As a result, even in mid‐winter, a large amount of ice melting occurs around the edge. It results in temperature decrease in the surface mixed water. During the 1993–1994 winter, the total volume ratio of ice melting to ice production is estimated at 0.76. The negative latent heat flux from the ice melting is nearly comparable to the total atmospheric heat flux around the ice edge. Furthermore, the meltwater supply to the surface layer is estimated to be approximately 3.5 times the annual Amur River inflow. Thus it is concluded that the ice melting around the extending ice edge is a significant factor for the heat and salt balance between the sea ice and the surface mixed layer and plays an important role in the maintenance of the large seasonal sea ice extent in the Sea of Okhotsk.
Hydrothermal venting in magma deserts: The ultraslow‐spreading Gakkel and Southwest Indian Ridges
Authors: Baker Edward T. , Edmonds Henrietta N. , Michael Peter J. , Bach Wolfgang , Dick Henry J. B. , Snow Jonathan E. , Walker Sharon L. , Banerjee Neil R. , Langmuir Charles H.
Published: August 2004

Detailed hydrothermal surveys over ridges with spreading rates of 50–150 mm/yr have found a linear relation between spreading rate and the spatial frequency of hydrothermal venting, but the validity of this relation at slow and ultraslow ridges is unproved. Here we compare hydrothermal plume surveys along three sections of the Gakkel Ridge (Arctic Ocean) and the Southwest Indian Ridge (SWIR) to determine if hydrothermal activity is similarly distributed among these ultraslow ridge sections and if these distributions follow the hypothesized linear trend derived from surveys along fast ridges. Along the Gakkel Ridge, most apparent vent sites occur on volcanic highs, and the extraordinarily weak vertical density gradient of the deep Arctic permits plumes to rise above the axial bathymetry. Individual plumes can thus be extensively dispersed along axis, to distances >200 km, and ∼75% of the total axial length surveyed is overlain by plumes. Detailed mapping of these plumes points to only 9–10 active sites in 850 km, however, yielding a site frequency Fs, sites/100 km of ridge length, of 1.1–1.2. Plumes detected along the SWIR are considerably less extensive for two reasons: an apparent paucity of active vent fields on volcanic highs and a normal deep‐ocean density gradient that prevents extended plume rise. Along a western SWIR section (10°–23°E) we identify 3–8 sites, so Fs = 0.3–0.8; along a previously surveyed 440 km section of the eastern SWIR (58°–66°E), 6 sites yield Fs = 1.3. Plotting spreading rate (us) versus Fs, the ultraslow ridges and eight other ridge sections, spanning the global range of spreading rate, establish a robust linear trend (Fs = 0.98 + 0.015us), implying that the long‐term heat supply is the first‐order control on the global distribution of hydrothermal activity. Normalizing Fs to the delivery rate of basaltic magma suggests that ultraslow ridges are several times more efficient than faster‐spreading ridges in supporting active vent fields. This increased efficiency could derive from some combination of three‐dimensional magma focusing at volcanic centers, deep mining of heat from gabbroic intrusions and direct cooling of the upper mantle, and nonmagmatic heat supplied by exothermic serpentinization.
How islands stir and fertilize the upper ocean
Authors: Hasegawa D. , Yamazaki H. , Lueck R. G. , Seuront L.
Published: August 2004

Large differences between the upstream and lee side flow characteristics of an isolated island in the Kuroshio have been identified from a three‐dimensional velocity survey and from vertical profiles of fine‐ and micro‐structure. In the island wake, the relative vorticity is O(10f), the horizontal current divergence indicates upwelling of O(0.01 m s−1), and the rate of dissipation of kinetic energy is O(10−4 W kg−1). Isopycnal surfaces shoal by 60 m on the lee side and surface nitrate concentration increases seven‐fold. Flow blockage by the island and the Izu‐Ogasawara Ridge on its flanks, induces horizontal and vertical flow separation. The associated lateral and vertical shear drive the upwelling and the vertical mixing in the wake and produces a very pronounced “island mass effect.”
ICESat observations of Arctic sea ice: A first look
Authors: Kwok Ron , Zwally H. Jay , Yi Donghui
Published: August 2004

Analysis of near‐coincident ICESat and RADARSAT imagery shows that the retrieved elevations from the laser altimeter are sensitive to new openings (containing thin ice or open water) in the sea ice cover as well as to surface relief of old and first‐year ice. The precision of the elevation estimates, measured over relatively flat sea ice, is ∼2 cm. Using the thickness of thin‐ice in recent openings to estimate sea level references, we obtain the sea‐ice freeboard along the altimeter tracks. This step is necessitated by the large uncertainties in the sea surface topography compared to that required for accurate determination of freeboard. Unknown snow depth introduces the largest uncertainty in the conversion of freeboard to ice thickness. Surface roughness is also derived, for the first time, from the variability of successive elevation estimates along the altimeter track. Overall, these ICESat measurements provide an unprecedented view of the Arctic Ocean ice cover at length scales at and above the spatial dimension of the altimeter footprint of ∼70 m.
Executive Leadership and its Technical Details: Teaching Approach for Steelscreen.com and Beyond
Authors: Subirana Brian
Published: August 2004

In this paper, I contend that executive leaders can and should be prepared to spot timely opportunities and prevent major failures, even if it requires understanding IT technical details. An essential part of executive leadership is exception management - and exceptions occur everywhere, often surfacing first as details, nothing more. Here I present two cases that show technology is no exception. In this paper, I outline how Steelscreen.com 's and RoweCom's early years can illustrate why understanding IT technical details helps explain IT-related failures and successes. In particular, I outline the differences between the two stories and argue that the show stopper for Steelscreen was at its crux a technology detail - the other shortcomings could have been addressed elsewhere. I conclude with some recommendations for executive leaders and a brief outline of a teaching approach suggestion for an MBA or a Senior Executive IT class based on the ideas presented.
Polarization compensation for a birefringent Fabry–Perot interferometer
Authors: Kim Zaeil , Kim So Young , Lee Seung Goo , Kim Chang Wha , Park Q-Han , Cho D.
Published: August 2004

We built a Fabry–Perot interferometer for an atom-trapping experiment and devised a procedure to characterize and compensate the birefringence coming from the mirrors. Our design of the mirror mounts is compatible with the ultrahigh vacuum environment and it allows easy and durable alignment. The mounts provide mechanical stability but at the expense of measurable stress-induced mirror reflection birefringence. We developed an intuitive but mathematically general theory to describe the interferometer birefringence. The theory allows us to measure the birefringence in a systematic way. It also provides us with a prescription to compensate it and to create desired polarization state inside the interferometer by using a pair of common wave plates. We successfully applied the procedure to our Fabry–Perot interferometer to demonstrate its usefulness.
Compact high-voltage generator of primary power based on shock wave depolarization of lead zirconate titanate piezoelectric ceramics
Authors: Shkuratov Sergey I. , Talantsev Evgueni F. , Menon Latika , Temkin Henryk , Baird Jason , Altgilbers Larry L.
Published: August 2004

The design and performance of a compact explosive-driven high-voltage primary power generator is presented. The generator utilizes a fundamental physical effect—depolarization of ferroelectric materials under longitudinal shock wave impact, when the shock wave is initiated along the polarization vector P. These primary power sources, containing energy-carrying elements made of lead zirconate titanate poled piezoelectric ceramics, with the volume from 0.35 to 3.3 cm3, are capable of producing pulses of high voltage with amplitudes up to 21.4 kV. The amplitude and full width at half-maximum of the high-voltage pulses are directly proportional to the thickness of the energy-carrying element, with coefficients of proportionality of 3.42±0.12 kV/mm (amplitude) and 0.125±0.01 μs/mm (width). The specific energy density of these ferroelectric energy-carrying elements reaches 76 mJ/cm3.
Nanogranular FexNi23−xB6 phase formation during devitrificationof nickel-rich Ni64Fe16Zr7B12Au1 amorphous alloy
Authors: Idzikowski B. , Szajek A. , Greneche J.-M. , Kovač J.
Published: August 2004

Nickel-rich amorphous precursors with chemical composition of Ni64Fe16Zr7B12Au1 were produced by melt-spinning technique and then heat treated at temperatures ranging from 435to600°C for 1h to form a nanostructure. Properties of the amorphous and the nanocrystalline samples were investigated by the differential scanning calorimetry, the x-ray diffraction (XRD), the vibrating sample magnetometry, and Mössbauer techniques. The annealing favors the emergence of cubic FexNi23−xB6 crystalline grains (10–25nm in diameter). Magnetic measurements made at 4.2–1100K reveal rather high value of saturation magnetization (nearly 60 and 40Am2∕kg at 4.2K and room temperature, respectively) in amorphous as well as in nanocrystalline states. These facts are consistent with 300K Fe57 Mössbauer effect results which are well supported by the calculations of Ni and Fe magnetic moments in Ni23B6 and Fe23B6 phases, using the spin polarized tight binding linear muffin-tin orbital method. However, anomalous high magnetic moments of Fe atoms were found in some inequivalent positions in the crystal structure.
Cathodoluminescence study of deep ultraviolet quantum wells grown on maskless laterally epitaxial overgrown AlGaN
Authors: Katona T. M. , Craven M. D. , Speck J. S. , DenBaars S. P.
Published: August 2004

We have investigated the cathodoluminescence properties of deep UV quantum wells with an emission wavelength of 287nm grown on maskless lateral epitaxial overgrown Al0.96Ga0.04N. AlN was grown on sapphire via metalorganic chemical vapor deposition. Parallel, periodic trenches were etched in the AlN and Al0.96Ga0.04N was regrown laterally from the unetched mesas. Al0.42Ga0.58N∕Al0.36Ga0.64N quantum wells were then grown on the uncoalesced stripes. Cathodoluminescence was performed on both the laterally overgrown “wings” and unetched “seed” material. Emission from quantum wells located above the wing region was observed to be more intense than emission above the seed region. Depth dependent cathodoluminescence showed that deep level recombination at 3.58eV(346nm), 2.77eV(448nm), and 2.14eV(579nm) was present throughout the n-type Al0.45Ga0.55N and the laterally overgrown unintentionally doped Al0.96Ga0.04N.
Toroidal rotation in DIII-D in electron cyclotron heating and Ohmic H-mode discharges
Authors: deGrassie J. S. , Burrell K. H. , Baylor L. R. , Houlberg W. , Lohr J.
Published: August 2004

Spatially and temporally resolved toroidal rotation measurements have been made in DIII-D [J. L. Luxon, Nucl. Fusion 42, 614 (2002)] discharges with no externally applied torque. The velocity measurements are made using the charge exchange recombination (CER) technique viewing emission from the intrinsic carbon impurity in deuterium discharges. Three cases have been studied: L mode and H mode with Ohmic heating and H mode with electron cyclotron heating (ECH). The ECH H mode has carbon counter-rotation in the center of the plasma, and co-rotation outside, where co- and counter- are relative to the direction of the toroidal plasma current. The Ohmic H mode has carbon rotation everywhere in the co-direction. Neoclassical theory is applied to compute the deuterium toroidal velocity and it is found that the counter-rotation measured for carbon in the core of the ECH H mode is also thus predicted for the bulk deuterium species. Short blips of neutral beams (NB) must be used for the CER technique and these blips do apply a toroidal torque. Care is taken to verify that a nonperturbative measurement is made; data from the first 2 ms of NB injection in each discharge are used for this measurement.
Distribution of activation energies on undoped and SiC-doped superconducting MgB2 wires
Authors: Martínez E. , Navarro R.
Published: August 2004

The distribution of the activation energies, m(U0), of undoped and SiC-doped MgB2 wires has been estimated from magnetic relaxation measurements using the Hagen-Griessen inversion scheme. Ni-sheathed wires fabricated by the powder-in-tube (PIT) technique, using the ex situ reaction, have been analyzed. The enhancement of the superconducting properties under high magnetic fields (B>2T) on doped wires is evidenced by the increase of the upper critical, Bc2, and irreversibility, Birr, fields, and by the shift of the pinning energy distribution to higher energy values. The obtained m(U0) distributions might be also explained by a nonlinear current dependence of the pinning energies: U(J,B,T)=[U*(B,T)∕μ]*[(Jc∕J)μ−1] with μ=0.2–0.4.
Second- and third- harmonic generation in single-walled carbon nanotubes at nanosecond time scale
Authors: De Dominicis L. , Botti S. , Asilyan L. S. , Ciardi R. , Fantoni R. , Terranova M. L. , Fiori A. , Orlanducci S. , Appolloni R.
Published: August 2004

Second- and third-harmonic generation in single-walled carbon nanotube films is experimentally investigated with the fundamental 1064nm radiation from a Q-switched Nd:YAG laser. Measurements were performed both on commercially available carbon nanotubes and on samples of carbon nanotubes grown with a catalyst-free method. Third-harmonic generation was observed in both samples while only the sample grown with a catalyst-free method generated a second-harmonic signal. The quantum yield of second- and third-harmonic signal was proven to scale, respectively, with the second and third power of the pump pulse energy up to intensities of 109W∕cm2.
Carrier relaxation in InGaN∕GaN quantum wells with nanometer-scale cluster structures
Authors: Wang Hsiang-Chen , Lin Shih-Chun , Lu Yen-Chen , Cheng Yung-Chen , Yang C. C. , Ma Kung-Jen
Published: August 2004

Temperature-dependent femtosecond pump–probe experiments are performed to explore the ultrafast carrier-relaxation processes in an InGaN∕GaN quantum-well sample, in which nanometer-scale cluster structures have been identified. Combined with the time-resolved photoluminescence results, we can identify three stages of carrier relaxation. The fast-decay time, ranging from several hundred femtoseconds to 1 picosecond, corresponds to the process reaching a local quasi-equilibrium condition, in which carriers reach a thermal distribution within one or a few nearby indium-rich clusters. The slow-decay time, ranging from tens to a couple hundred picoseconds, corresponds to the process reaching a global quasi-equilibrium condition, in which carriers reach a thermal distribution among different clusters of various potential minima. In this stage, the mechanism of carrier transport over barriers between clusters dominates the relaxation process. Finally, carrier recombination dominates the relaxation process with the carrier lifetime in the range of a few nanoseconds.
On the origin of strain fluctuation in strained-Si grown on SiGe-on-insulator and SiGe virtual substrates
Authors: Kutsukake Kentaro , Usami Noritaka , Ujihara Toru , Fujiwara Kozo , Sazaki Gen , Nakajima Kazuo
Published: August 2004

We investigated the microscopic strain fluctuation in strained-Si grown on SiGe-on-insulator (SGOI) and SiGe virtual substrates, and clarified the origins of the strain fluctuation in the strained-Si film. A periodic strain fluctuation, which reflects a cross-hatch pattern of the substrate, was observed in the sample on the virtual substrate. On the other hand, a featureless strain fluctuation with suppressed amplitude was observed in the sample on SGOI substrate. By analyzing the correlation of the Raman peak positions of the Si–Si modes in strained-Si and SiGe, the dominant mechanism of the strain fluctuation in the strained Si film was found to be the compositional fluctuation in underlying SiGe for the sample on SGOI, and the strain fluctuation reflecting the cross-hatch pattern for the sample on the virtual substrate, respectively.
Effect of GaN cap layer grown at a low temperature on electrical characteristics of Al0.25Ga0.75N∕GaN heterojunction field-effect transistors
Authors: Kao C. J. , Sheu J. K. , Lai W. C. , Lee M. L. , Chen M. C. , Chi G. C.
Published: August 2004

This study examined the effect of GaN grown by metalorganic vapor phase epitaxy at low temperature (LT-GaN) on the surface of Al0.25Ga0.75N∕GaN heterostructures. Depositing a high-resistivity LT-GaN surface layer on the Al0.25Ga0.75N∕GaN heterostructures increased both the sheet carrier concentrations and the electron mobility. This enhancement changed when the LT-GaN high-resistivity layer was removed by high-density-plasma etching. These observations are attributable to the passivation effect, implying that the LT-GaN behaves like a dielectric film, such as silicon dioxide, to passivate the surface states, yielding a different, maybe lower, electronic density of states than that of the Al0.25Ga0.75N free surface. Hall-effect measurement and gate lag measurement were performed on the field-effect transistor devices to clarify the effect of LT-GaN cap layer on Al0.25Ga0.75N∕GaN heterostructures.
Reexamination of some spintronic field-effect device concepts
Authors: Bandyopadhyay S. , Cahay M.
Published: August 2004

Current interest in spintronics is largely motivated by a belief that spin-based devices (e.g., spin field-effect transistors) will be faster and consume less power than their electronic counterparts. Here we show that this is generally untrue. Unless materials with extremely strong spin-orbit interaction can be developed, the spintronic devices will not measure up to their electronic cousins. We also show that some recently proposed modifications of the original spin field-effect transistor concept of Datta and Das [Appl. Phys. Lett. 56, 665 (1990)] actually lead to worse performance than the original construct.
Two-dimensional metallo-dielectric photonic crystals embedded in anodic porous alumina for optical wavelengths
Authors: Takayama Osamu , Cada Michael
Published: August 2004

A theoretical study is presented for hexagonal lattice metallic pillar photonic crystals in anodic porous alumina with a lattice constant of 500nm. The objective of the investigation is to design a two-dimensional metallo-dielectric photonic crystal with an anodic porous alumina template. Optical responses are calculated for silver pillars of radii 100nm, and 200nm in porous alumina. The nature of their stop bands and attenuation in the near-infrared region is investigated. Calculations reveal that two-dimensional photonic band gaps for the TM polarization exist at visible wavelengths when the radius is 200nm.
Field emission from aCa nanotip grown on aMo⟨110⟩ microtip
Authors: Zhao Xin , Outlaw R. A. , Champion R. L. , Wang J. J. , Manos D. M. , Holloway B. C.
Published: August 2004

We have observed field emission with an energy distribution of 68meV full width at half maximum (FWHM) from a thermally cleaned Mo⟨110⟩ single tip. The emission spectra are taken with the emitting surface at 295K, using a double-pass cylindrical mirror analyzer in ultrahigh vacuum. This narrow energy distribution is attributed to a nanotip spontaneously formed on the ∼75nm radius Mo tip from in situ buildup by field-induced surface diffusion. Auger electron spectroscopy showed that residual surface Ca segregated from the bulk during thermal cleaning and is likely the source of mobile atoms that formed the nanotip. The emission spectra show a discernible doublet that is attributed to a variation in the localized density of states of the nanotip. Sub-Langmuir oxygen exposure of the Mo tip immediately increased the energy distribution to a FWHM of >1eV.
Proton-beam-induced defect levels in CuInSe2 thin-film absorbers: An investigation on nonradiative electron transitions
Authors: Akaki Yoji , Yoshino Kenji , Ikari Tetsuo , Kawakita Shirou , Imaizumi Mitsuru , Niki Shigeru , Sakurai Keiichiro , Ishizuka Shogo , Ohshima Takeshi
Published: August 2004

Electron nonradiative relaxation through the proton-irradiation-induced defects in CuInSe2 solar cell material were investigated by using a piezoelectric photothermal spectroscopy (PPTS). Among the observed three peaks at 1.01, 0.93, and 0.84eV, it was concluded that the peak at 0.84eV was due to the proton-irradiation-induced defect. This is because this peak appeared after irradiation with the proton energy of 0.38MeV and the fluence of 1×1014cm−2. The peaks at 1.01 and 0.93eV were attributed to free band-edge exciton and intrinsic defect level, respectively. The intensities for the latter two peaks were not affected by the irradiation. Since the irradiation defect was clearly observed at room temperature, we concluded that the PPTS technique was a very sensitive tool to study the defect level in the irradiated semiconductor thin-film solar cell structures.