bluuebunny/crossref_metadata_2025 huggingface dataset:
Neue Fehlerabschätzungen für verschiedene Iterationsverfahren
Authors: Schröder Johann
Published: May 2007

Ausgehend von einem an anderer Stelle1) bewiesenen Satz über das abstrakte Iterationsverfahren un+1 = Tun werden verschärfte Fehlerabschätzungen hergeleitet für Iterationsverfahren bei linearen und nichtlinearen Gleichungssystemen sowie Anfangs‐ und Randwertaufgaben für gewöhnliche Differentialgleichungen.
Berechnung von teilweise eingespannten rechteckigen Platten bei Vorgabe von Randmomenten
Authors: Wegner Udo
Published: May 2007

Es wird ein nicht‐vollständiges, koorthogonales, komplexes System von biharmonischen Funktionen untersucht, das bei vielen der in der Überschrift genannten Aufgaben die Koeffizienten in geschlossener Form darzustellen gestattet, ähnlich der Fourier‐Darstellung. Das Verfahren wird an einigen technisch wichtigen Problemen erläutert.
Die „Neumannsche Methode”︁ zur Approximation einer durch Beobachtungen gegebenen Funktion und ihr Zusammenhang mit der mechanischen Quadratur nach Gauß‐Jacobi
Authors: Mauersberger Peter
Published: May 2007

Die hier vorgetragene Verallgemeinerung der von F. Neumann für die Entwicklung nach Kugelfunktionen angegebene Methode löst die Aufgabe, eine durch naturwissenschaftliche Beobachtungen nur für diskrete Werte der unabhängigen Veränderlichen vorgegebene Funktion von n Variablen mittels orthogonaler Polynome im Sinne der Methode der kleinsten Quadrate zu approximieren, ohne daß eine Ausgleichungsrechnung durchgeführt werden muß. Es wird der Zusammenhang mit der mechanischen Quadratur nach Gauß‐Jacobi aufgezeigt und zur Vereinfachung der Beweisführung der „Neumann schen Methode”︁ und zu ihrer Ergänzung herangezogen.
Der Raumschlitten
Authors: Aumann Georg
Published: May 2007

Ein Raumschlitten ist ein starrer Körper, der sich so bewegt, daß in einem körperfesten Punkt die absolute Geschwindigkeit zu einer vorgegebenen körperfesten Richtung entweder stets senkrecht (I) oder stets parallel (II) ist. Es werden die Bewegungsgleichungen eines kräftefreien Raumschlittens aufgestellt, und es wird im kugelsymmetrischen Falle gezeigt, daß neben den trivialen periodischen Geschwindigkeitsabläufen im Fall (I) nur aperiodische, im Fall (II) aber auch periodische Geschwindigkeitsabläufe möglich sind.
Finite Bending of a Plate into a Spherical Shell
Authors: Seth B. R.
Published: May 2007

By using the theorie of finite deformation it is shown that a circular plate of radius d can be bent into a spherical shell by forces and couples applied to the edges only, the inner surface a and the outer surface b of the shell being free from tractions. The radius of the plate is assumed to be small compared with a and b so that (d/a2) can be neglected. The particular case in which the Possion's ratio σ is equal to 1/3 has been discussed in detail. The percentage of decrease in thickness and the change in the edge‐radii have been obtained.
Vibrations of a beam on elastic foundation II
Authors: Mathews P. M.
Published: May 2007

In an earlier paper, the equations describing the vibrations of a beam on elastic foundation under the action of an alternating force whose point of application moves along the beam was solved by the author, neglecting damping. The effect of damping is taken into account in the present work, and explicit solutions, valid for all frequencies and velocities of the applied force, are obtained. In qualitative features the most obvious difference from the undamped case is that, for non‐zero velocity, the displacements of the beam are no longer symmetric about the instantaneous position of the applied force, but are greater behind than ahead of this position.
Resistance on a sphere due to a circular vortex filament in an uniform flow of a perfect liquid
Authors: Mitra M. K.
Published: May 2007

This paper gives a formula for resistance (in series of Legendre functions) on a sphere due to a circular vortex filament in an uniform flow of a perfect liquid. The stream function of the motion has been found by Butler's sphere Theorem and then the resistance on the sphere is calculated by means of Bernoulli's pressure equation.
Theorie und Experiment zum Reibungswiderstand der glatten rotierenden Scheibe bei turbulenter Strömung
Authors: Broecker E.
Published: May 2007

Der Reibungswiderstand rotierender Scheiben in Gehäusen ist theoretisch und experimentell sowohl für die Laminarströmung als auch für die laminare und turbulente Grenzschicht zwischen der Kernströmung und der rotierenden Scheibe bzw. der gegenüberliegenden Wand untersucht worden; entsprechende Ergebnisse sind für die frei rotierende Scheibe bei laminarer und turbulenter Grenzschicht bekannt.

Theorie und Experiment sind für die verschiedenen Fälle in guter Übereinstimmung mit Ausnahme des Falles der Scheibe im Gehäuse bei turbulenter Grenzschichtströmung, was bisher mit den Annahmen zur Lösung der Grenzschicht‐Impulsgleichungen begründet wurde. Die folgende Untersuchung zeigt, daß das theoretische Ergebnis experimentell nicht nachweisbar ist und behandelt zwei Fälle unterschiedlicher Wandbegrenzung, die eine allmähliche bzw. schnelle Änderung des Drehmomentenbeiwertes vom unteren Grenzwert der Scheibe im engen Gehäuse zum oberen Grenzwert der freien Scheibe ergeben.
Newborn screening for cystic fibrosis: Techniques and strategies
Authors: Wilcken Bridget
Published: May 2007

Newborn screening for cystic fibrosis has been carried out for over 25 years, and clinical and cost benefits have been documented. There is still much variation in the methods and strategies adopted. All current screening programmes use a measurement of immunoreactive trypsin as a primary screening test, and in most, a second tier test involves analysing DNA mutations. The choice of DNA mutations depends on the genetic background in the region, and considerations of cost. Using DNA analysis as part of a screening procedure has introduced unwanted carrier detection, and protocols have now been devised in an attempt to avoid this. There are at least seven distinct protocols in use, all of which have different advantages and disadvantages, and no method or strategy will suit every region. Further careful study of performance and costs of various strategies is needed.
Dexamethasone treatment differentially affects the oxidative energy metabolism of rat brain mitochondria in developing and adult animals
Authors: Pandya Jignesh D. , Agarwal Neeraj A. , Katyare Surendra S.
Published: May 2007

We studied the effect of repeated exposure to dexamethasone (Dex) treatment on rat brain mitochondrial oxidative energy metabolism in developing rats at different postnatal ages, i.e. 2–5 week and in adults. The animals were injected with a dose of 2 mg of Dex/kg body weight at around 7:00 a.m. for three alternative days prior to the day of sacrifice; the control group animals received saline vehicle. We measured rates of respiration with different substrates, viz. glutamate, pyruvate + malate, succinate and ascorbate + TMPD; the contents of individual cytochromes and the dehydrogenases and ATPase activities. Dex treatment, in general, stimulated the state 3 rates of respiration rates in young animals in age‐dependent and substrate‐specific manner except for the 3 week group, whereas in the adults there was substantial inhibition of the respiration. The pattern of dehydrogenases activities matched with respiration rates. Dex treatment also resulted in uncoupling of the second and third site of phosphorylation in 3‐week‐old animals and in the adults. The contents of cytochromeaa3,band ATPase activities decreased significantly after Dex treatment in all the age groups. The results thus emphasize that exposure to repeated Dex treatment can significantly influence the oxidative energy metabolism of brain mitochondria in young growing animals as well as in adults.
Transient changes in the localization and activity of ecto‐nucleotidases in rat hippocampus following lipopolysaccharide treatment
Authors: Kittel Ágnes , Sperlágh Beata , Pelletier Julie , Sévigny Jean , Kirley Terence L.
Published: May 2007

The concentrations of extracellularly released nucleotides are controlled by metabolism via ecto‐nucleotidases, but the precise physiological roles of the ecto‐nucleoside triphosphate diphosphohydrolases in the modulation of purinergic receptor signalling are still unclear. Bacterial endotoxin lipopolysaccharide (LPS) treatment (administered intraperitoneally, 2 mg/kg body weight) of rats resulted in no significant changes in the overall ecto‐nucleotidase activities of the hippocampus, however, LPS treatment did cause transient changes in the morphology of endothelial cells and pericytes and in the localization pattern of ecto‐ATPase activity in rat hippocampus. The transient decrease in NTPDase1 (ecto‐nucleoside triphosphate diphosphohydrolase1) activity, located on the luminal side of the endothelial cells, was balanced by increases in ecto‐nucleotidase activities in pericytes and at other sites, consistent with an unchanged overall ecto‐ATPase activity of the hippocampus.

Since the transient loss of NTPDase1 activity was not accompanied by a loss of NTPDase1 protein, we hypothesize that LPS caused transient alterations in the lipid membranes, since NTPDase1 activity is known to be sensitive to changes in membrane structure via its transmembrane domains. After 2–3 days, the LPS‐induced changes in cell morphology and ecto‐nucleotidase localization disappeared. We conclude that a low dose of LPS causes transient changes in the localization pattern of ecto‐nucleotidases in endothelial cells and pericytes, which, coupled with the observed cellular morphological changes, may indicate modified cellular signalling in the hippocampus.
Christiaan Barnard, One Life
Authors: Savage Jacqueline
Published: May 2007

Barnard Christiaan, Curtis Bill Pepper, Christiaan Barnard, One Life, 1970, The Macmillan Co., 402, $7.95.
Professional Nursing: (Foundations, Perspectives, and Relationships), ed. 8
Authors: Crawford Mabel
Published: May 2007

Eugenia Kennedy Spalding RN MA DHL, Lucille E. Notter RN MA Ed D, Professional Nursing: (Foundations, Perspectives, and Relationships), ed. 8, 1970, J. B. Lippincott Company, 677
Transplantation Reviews 7
Authors: Wolk Helen
Published: May 2007

Transplanfation Reviews 7, 1971, Williams & Wilkins, Baltimore, 178, $16.50
Decision Media
Authors: Wessel Linda
Published: May 2007

Decision Media, film: Philadelphia: J B Lippincott Company.
Clinical Guide to Undersirable Drug Interactions & Interferences
Authors: Mehaffy Nancy L.
Published: May 2007

S Garb MD, FACP, Clinical Guide to Undersirable Drug Interactions & Interferences, 1970, Springer Publishing Co, Inc, New York, 491, $12.50 clothbound.
Air Instrument Surgery, Volume 2: Orthopedics
Authors: Kraii Connie
Published: May 2007

RM Hall, Air Instrument Surgery, Volume 2: Orthopedics, 1972, Springer‐Verlag Publishing Co, Berlin, 509 pp, no price listed
The Story of Medicine in America
Authors: Ruhlow Nancy
Published: May 2007

Geoffrey Marks, William K Beatty, The Story of Medicine in America, 1973, Charles Scribner's Sons, New York, 416, $10.
Invasive Radiologic Diagnostic Procedures
Authors: MacClelland Doris C
Published: May 2007

Invasive Radiologic Diagnostic Procedures. Abbott, Mary Kilduff. F A Davis Co, 1915 Arch St, Philadelphia, Pa 19103, 1978, 57 pp, $3.95 paperback.
Nurse‐Client Interaction: Implementing the Nursing Process
Authors: Owen Charlotte
Published: May 2007

Nurse‐Client Interaction: Implementing the Nursing Process, fourth ed. By Sandra J. Sundeen, Gail Wiscarz Stuart, Elizabeth Anne DeSalvo Rankin, Sylvia Ann Cohen 1989, 383 pp $18.95 paperback
Surgery for the Morbidly Obese Patient
Authors: Snyder Rhonda P.
Published: May 2007

Surgery for the Morbidly Obese Patient Edited by Mervyn Deitel 1989, 400 pp $70 clothbound
Book Reviews: Nursing'94 Drug Handbook
Authors: Garrett Caroline K.
Published: May 2007

1994, 1,240 pp $24.95 plastic cover
Cardiac Surgery
Authors: Shartel Judith R.
Published: May 2007

By Patricia C. Seifert 1994, 496 pp $49.95 hardcover
Surgical Nursing
Authors: MacClelland Doris
Published: May 2007

Elizabeth J. Fish, Fluid and Electrolyte Balance: A Programmed Text, 9th ed, 1974, Williams and Wilkins Co, 428 Preston St, Baltimore, Md 21202, 375, paperback $6.25
Leadership in Nursing
Authors: Sullins Mary Lou
Published: May 2007

Marjorie Beyers, Leadership in Nursing, 1979, Nursing Resources, Inc, 12 Lakeside Park, 607 N Ave, Wakefield, Mass, 178, $8.50 paperback.
Heart Disease: New Dimensions of Nursing Care
Authors: Minckley Barbara
Published: May 2007

McIntyre, H Mildred, Garden Grove, Heart Disease: New Dimensions of Nursing Care, 1974, Trainex Press, Calif, 331 pp, $10.95.
Anaesthetics Resuscitation and Intensive Care
Authors: MacClelland Doris
Published: May 2007

Anaesthetics Resuscitation and Intensive Care, 4th ed. Norris, Walter, et al. New York: Longman Inc, 1974, 282 pp, $7 paperback.
Governing Hospitals: Trustees and the New Accountabilities
Authors: Kane Sister
Published: May 2007

Robert M. Cunningham Jr, Governing Hospitals: Trustees and the New Accountabilities, 1976, American Hospital Association, 840 N Lakeshore Dr, Chicago, III 60611, 176, $7.50.
Nursing Leadership: Theory and Process
Authors: Persson June C
Published: May 2007

Helen Yura, Dorothy Ozimek, Mary B Walsh, Nursing Leadership: Theory and Process, 1976, Appleton‐Century‐Crofts, 440 Park Ave S, New York, NY 10016, 237, $8.50 paperback.
Just Like Always—Cartoons for Operating Room Nurses
Authors: O'Dea Sue
Published: May 2007

Just Like Always—Cartoons for Operating Room Nurses. Janet W Peters. Stanford University Hospital, Stanford, Calif 94305, 1981, 95 pp, $6 paperback.
Influence of energetic wind and waves on gas transfer in a large wind–wave tunnel facility
Authors: Rhee T. S. , Nightingale P. D. , Woolf D. K. , Caulliez G. , Bowyer P. , Andreae M. O.
Published: May 2007

Air–water gas exchange experiments were carried out in a large wind wave tunnel in Marseille, France, to investigate gas transfer processes under energetic wind and wave fields, where macroscale breaking waves create bubble plumes (white caps) and turbulence on the water surface. We measured the gas transfer velocities of N2O, DMS, He, SF6, CH3Br, and total air. Their diffusivity and solubility span a large range, allowing us to investigate gas transfer mechanisms under a variety of physical conditions. We observed that the gas transfer velocities varied with friction velocity in a linear manner. Gas transfer in the presence of pure wind waves is generally consistent with the surface renewal model, as the gas transfer velocity has a strong dependence on diffusivity with an exponent of 0.53(±0.02). Contrary to expectations, the bubble plumes generated by breaking waves contributed relatively little in our pure wind wave experiments. Superposition of mechanically generated waves onto the wind waves in the high wind regime attenuated DMS gas transfer (as a function of friction velocity) across the air–water interface by ∼20% compared with gas transfer under pure wind waves, implying suppression of gas transfer directly across the sheared water surface. Greater transfer of less soluble gases may result from bubble‐mediated gas transfer.
Calcium isotope fractionation during coccolith formation in Emiliania huxleyi: Independence of growth and calcification rate
Authors: Langer Gerald , Gussone Nikolaus , Nehrke Gernot , Riebesell Ulf , Eisenhauer Anton , Thoms Silke
Published: May 2007

Recently, calcium isotope fractionation in the coccolithophore Emiliania huxleyi was shown to exhibit a significant temperature dependency. An important subsequent question in this context is whether the observed fractionation patterns are caused by temperature itself or related growth rate changes. In order to separate growth and calcification rate effects from direct temperature effects, batch culture experiments with the coccolithophore E. huxleyi were conducted under varying light intensities. Despite large changes in cellular growth and calcification rates, calcium isotope fractionation remained constant. Independence of calcium isotope fractionation on growth and calcification was also obtained in two additional sets of experiments in which growth rates changed in response to varying calcium concentration and seawater salinity. These experiments also showed no direct effects of calcium concentration and salinity on calcium isotope fractionation. Values for calcium isotope fractionation of E. huxleyi coccoliths fell within a range of −1.0 to −1.6 (1000 lnα), confirming earlier results. This range is similar to that observed in several foraminiferal species and coccolith oozes, suggesting a rather homogeneous calcium isotopic composition in marine biogenic calcite. Our data further show that the calcium isotope fractionation does not change with changing isotopic composition of seawater. This is a basic requirement for reconstructing the calcium isotopic composition of the ocean over time.
A statistical study of the relation of Pi 2 and plasma flows in the tail
Authors: Hsu Tung‐Shin , McPherron R. L.
Published: May 2007

In this paper, we examine some of the statistical properties of Pi 2 pulsations and their relation to plasma flow bursts in the tail. These statistics are based on a set of 462 expansion onsets identified by the AL index and Pi 2 pulsations. The most probable number of Pi 2 bursts per substorm is 2, but some substorms have as many as 6. The first Pi 2 burst corresponds to the expansion onset about 58% of the time, but 28% of the time, there is a pseudo‐breakup prior to the main onset. When there are multiple Pi 2 bursts per substorm, the time between bursts ranges from 5 to 50 min with 20 min as the mean separation. Multiple Pi 2 bursts are more probable in the expansion and recovery phase than in the growth phase. We have selected a subset of 48 events for which International Sun Earth Explorer 2 (ISEE‐2) was in the region of expected x‐line formation at the time of onset. Plasma flows were observed in 32 of these events. In this subset, 26 events appear to be bursty bulk flows (BBFs), while the remaining 7 events were probably ion streaming in the plasma sheet boundary layer. Thus about one half (26/48) of all Pi 2 events observed when ISEE‐2 was in the region of x‐line formation could be associated with BBFs inside the plasma sheet. An examination of the time separation between BBFs reveals a repetitive distribution which is similar to that between Pi 2 bursts. The slight discrepancy between these two distributions may be due to the localization of the plasma flows which causes some BBFs to be missed, and to the definition of BBFs which does not allow an event shorter than 10 min. The frequent association of BBF and Pi 2 and their similar distributions of time separation suggest that they are causally related. If so, the observed properties of Pi 2 pulsations suggest that most substorms are made up of a sequence of transient reconnection events.
Atmospheric deposition and surface stratification as controls of contrasting chlorophyll abundance in the North Indian Ocean
Authors: Patra Prabir K. , Kumar M. Dileep , Mahowald Natalie , Sarma V. V. S. S.
Published: May 2007

Intense upwelling during summer and convection in winter are believed to drive higher biological productivity in the Arabian Sea than in the Bay of Bengal. Although the Arabian Sea receives substantial atmospheric deposition of dust aerosols, its role in biological activity is unknown. We have analyzed chlorophyll‐a (SeaWiFS), absorbing aerosol index (TOMS), surface winds (NCEP), and modeled dust deposition and SST (OI) data during two distinct seasons June–August (JJA, summer months) and October–December (OND, winter months) for the period 1997–2004. Climatologies of physicochemical properties have been developed from World Ocean Atlas 2001 (WOA01). Our results suggest that despite the strong vertical supply of nutrients in the western and central Arabian Sea regions, maximal chlorophyll‐a was limited to the former region in both JJA and OND periods, suggesting the importance of atmospherically transported substances in determining chlorophyll abundance in the North Indian Ocean. Time‐averages (1997–2004) revealed chlorophyll abundances in northwestern regions are larger than in other regions of the respective basins. The NW regions of the Arabian Sea and the Bay of Bengal have exhibited contrasting chlorophyll distribution patterns during El Niño years (1997–1998 and 2002–2003; positive SST anomalies); decreased and increased chlorophyll contents in respective regions. Following the passage of tropical cyclones, SeaWiFS records depicted large areas in the Arabian Sea to experience intensified chlorophyll production with strong wind speeds of 55–65 knots whereas its enhanced production occurred only in small patches even under the influence of Orissa Super Cyclone of October 1999 (wind speed up to 140 knots) due to strong stratification.
Relative contributions of fossil and contemporary carbon sources to PM 2.5 aerosols at nine Interagency Monitoring for Protection of Visual Environments (IMPROVE) network sites
Authors: Bench Graham , Fallon Stewart , Schichtel Bret , Malm William , McDade Charles
Published: May 2007

Particulate matter aerosols contribute to haze diminishing vistas and scenery at national parks and wilderness areas within the United States. To increase understanding of the sources of carbonaceous aerosols at these settings, the total carbon loading and 14C/C ratio of PM 2.5 aerosols at nine Interagency Monitoring for Protection of Visual Environments (IMPROVE) network sites were measured. Aerosols were collected weekly in the summer and winter at one rural site, two urban sites, five sites located in national parks and one site located in a wildlife preserve. The carbon measurements together with the absence of 14C in fossil carbon materials and known 14C/C levels in contemporary carbon materials were used to derive contemporary and fossil carbon contents of the particulate matter. Contemporary and fossil carbon aerosol loadings varied across the sites and suggest different percentages of carbon source inputs. The urban sites had the highest fossil carbon loadings that comprised around 50% of the total carbon aerosol loading. The wildlife preserve and national park sites together with the rural site had much lower fossil carbon loading components. At these sites, variations in the total carbon aerosol loading were dominated by nonfossil carbon sources. This suggests that reduction of anthropogenic sources of fossil carbon aerosols may result only in little decrease in carbonaceous aerosol loading at many national parks and rural areas. Examination of the major sources of uncertainty that might cause contemporary carbon contents to be artificially high indicates that potential errors and biases in the methodology do not change the fundamental conclusions of this study.
Transport of forest fire emissions from Alaska and the Yukon Territory to Nova Scotia during summer 2004
Authors: Duck Thomas J. , Firanski Bernard J. , Millet Dylan B. , Goldstein Allen H. , Allan James , Holzinger Rupert , Worsnop Douglas R. , White Allen B. , Stohl Andreas , Dickinson Cameron S. , van Donkelaar Aaron
Published: May 2007

Emissions from forest fires in Alaska and the Yukon Territory were observed at Chebogue Point, Nova Scotia (43.7°N, 66.1°W), between 11 and 13 July 2004. Smoke aerosols were first detected in the free troposphere by a Raman lidar and extended up to 8 km altitude. The plume was not evident at the surface until the second day, when increases in CO, acetonitrile (CH3CN), benzene, and aerosol mass concentrations were observed by in situ instrumentation. Enhancement ratios for each species relative to CO agreed with the range of values from other measurements of the same plume. The surface aerosols had an elevated black carbon fraction relative to both CO and organic matter, and the ratio of black to organic carbon was higher than what is typically observed in fresh smoke. The emissions were tracked back to Alaska and the Yukon Territory using aerosol optical depth measurements from the Aqua MODIS satellite instrument, and the transport was reconstructed using the GEOS‐Chem and FLEXPART atmospheric models. The analysis suggests that aerosols were injected into the atmosphere in proportion to CO and that aerosol removal processes were weak during the 7 to 9 day transit time in the free troposphere. Transport of the tracers to the ground was strongly connected to synoptic‐scale features in the surface meteorology.
Down‐regulation of human RNA/DNA helicase SUV3 induces apoptosis by a caspase‐ and AIF‐dependent pathway
Authors: Szczesny Roman J. , Obriot Helene , Paczkowska Aleksandra , Jedrzejczak Robert , Dmochowska Aleksandra , Bartnik Ewa , Formstecher Pierre , Polakowska Renata , Stepien Piotr P.
Published: May 2007

Background information. The nuclear gene hSUV3 (human SUV3) encodes an ATP‐dependent DNA/RNA helicase. In the yeast Saccharomyces cerevisiae the orthologous Suv3 protein is localized in mitochondria, and is a subunit of the degradosome complex which regulates RNA surveillance and turnover. In contrast, the functions of human SUV3 are not known to date.

Results. In the present study, we show that a fraction of human SUV3 helicase is localized in the nucleus. Using small interfering RNA gene silencing in HeLa cells, we demonstrate that down‐regulation of hSUV3 results in cell cycle perturbations and in apoptosis, which is both AIF‐ and caspase‐dependent, and proceeds with the induction of p53.

Conclusions. In addition to its mitochondrial localization, human SUV3 plays an important role in the nucleus and is probably involved in chromatin maintenance.
Trafficking and synaptic anchoring of ionotropic inhibitory neurotransmitter receptors
Authors: Kneussel Matthias , Loebrich Sven
Published: May 2007

Neurotransmitter receptors are subject to microtubule‐based transport between intracellular organelles and the neuronal plasma membrane. Receptors that arrive at plasma membrane compartments diffuse laterally within the plane of the cellular surface. To achieve immobilization at their sites of action, cytoplasmic receptor residues bind to submembrane proteins, which are coupled to the underlying cytoskeleton by multiprotein scaffolds. GABAARs (γ‐aminobutyric type A receptors) and GlyRs (glycine receptors) are the major inhibitory receptors in the central nervous system. At inhibitory postsynaptic sites, all GlyRs and the majority of GABAARs directly or indirectly couple to gephyrin, a multimeric PSD (postsynaptic density) component. In addition to cluster formations at axo‐dendritic contacts, individual GABAAR subtypes also anchor and concentrate at extrasynaptic positions, either through association with gephyrin or direct interaction with the ERM (ezrin/radixin/moesin) family protein radixin. In addition to their role in diffusion trapping of surface receptors, scaffold components also undergo rapid exchange to/from and between postsynaptic specializations, leading to a dynamic equilibrium of receptor—scaffold complexes. Moreover, scaffold components serve as adaptor proteins that mediate specificity in intracellular transport complexes. In the present review, we discuss the dynamic delivery, stabilization and removal of inhibitory receptors at synaptic sites.
Growth factor regulation of hyaluronan synthesis and degradation in human dermal fibroblasts: importance of hyaluronan for the mitogenic response of PDGF-BB
Authors: Li Lingli , Asteriou Trias , Bernert Berit , Heldin Carl-Henrik , Heldin Paraskevi
Published: May 2007

The glycosaminoglycan hyaluronan is important in many tissuerepair processes. We have investigated the synthesis of hyaluronan in a panel of cell lines of fibroblastic and epithelial origin in response to PDGF (platelet-derived growth factor)-BB and other growth factors. Human dermal fibroblasts exhibited the highest hyaluronan-synthesizing activity in response to PDGF-BB. Analysis of HAS (hyaluronan synthase) and HYAL (hyaluronidase) mRNA expression showed that PDGF-BB treatment induced a 3-fold increase in the already high level of HAS2 mRNA, and increases in HAS1 and HYAL1 mRNA, whereas the levels of HAS3 and HYAL2 mRNA were not affected. Furthermore, PDGF-BB also increased the amount and activity of HAS2 protein, but not of HYAL1 and HYAL2 proteins. Using inhibitors for MEK1/2 [MAPK (mitogen-activated protein kinase)/ERK (extracellular-signal-regulated kinase) kinase 1/2] (U0126) and for PI3K (phosphoinositide 3-kinase) (LY294002), as well as the SN50 inhibitor, which prevents translocation of the active NF-κB (nuclear factor κB) to the nucleus, we observed a complete inhibition of both HAS2 transcriptional activity and hyaluronan synthesis, whereas inhibitors of other signalling pathways were without any significant effect. TGF-β1 (transforming growth factor-β1) did not increase the activity of hyaluronan synthesis in dermal fibroblasts, but increased the activity of HYALs. Importantly, inhibition of hyaluronan binding to its receptor CD44 by the monoclonal antibody Hermes-1, inhibited PDGF-BB-stimulated [3H]thymidine incorporation of dermal fibroblasts. We conclude that the ERK MAPK and PI3K signalling pathways are necessary for the regulation of hyaluronan synthesis by PDGF-BB, and that prevention of its binding to CD44 inhibits PDGF-BB-induced cell growth.
Constant-phase-element (CPE) modeling of ferroelectric random-access memory lead zirconate-titanate (PZT) capacitors
Authors: Morrison Finlay D. , Jung Dong Jin , Scott James F.
Published: May 2007

Several commercial high density ferroelectric random access memory (FeRAM) devices utilize stacks of submicron lead zirconate-titanate (PZT) capacitors. The low-field electrical characteristics of these capacitors display a specific frequency dependence which is best represented by a constant phase element (CPE) in the equivalent circuit diagram. The microscopic origin of such CPEs in the general literature is still of some debate, often being attributed to fractal dimensionality of the capacitor, near-electrode gradients in the dielectric, fringing fields near the electrode perimeter or, more generally, a distribution of relaxation times. We discuss these possibilities.
Physics of strain effects in semiconductors and metal-oxide-semiconductor field-effect transistors
Authors: Sun Y. , Thompson S. E. , Nishida T.
Published: May 2007

A detailed theoretical picture is given for the physics of strain effects in bulk semiconductors and surface Si, Ge, and III–V channel metal-oxide-semiconductor field-effect transistors. For the technologically important in-plane biaxial and longitudinal uniaxial stress, changes in energy band splitting and warping, effective mass, and scattering are investigated by symmetry, tight-binding, and k⋅p methods. The results show both types of stress split the Si conduction band while only longitudinal uniaxial stress along ⟨110⟩ splits the Ge conduction band. The longitudinal uniaxial stress warps the conduction band in all semiconductors. The physics of the strain altered valence bands for Si, Ge, and III–V semiconductors are shown to be similar although the strain enhancement of hole mobility is largest for longitudinal uniaxial compression in ⟨110⟩ channel devices and channel materials with substantial differences between heavy and light hole masses such as Ge and GaAs. Furthermore, for all these materials, uniaxial is shown to offer advantages over biaxial stress: additive strain and confinement splitting, larger two dimensional in-plane density of states, smaller conductivity mass, and less band gap narrowing.
Computation of three-dimensional tokamak and spherical torus equilibria
Authors: Park Jong-kyu , Boozer Allen H. , Glasser Alan H.
Published: May 2007

A nominally axisymmetric plasma configuration, such as a tokamak or a spherical torus, is highly sensitive to nonaxisymmetric magnetic perturbations due to currents outside of the plasma. The high sensitivity means that the primary interest is in the response of the plasma to very small perturbations, i.e., ∣b⃗∕B⃗∣≈10−2 to 10−4, which can be calculated using the theory of perturbed equilibria. The ideal perturbed equilibrium code (IPEC) is described and applied to the study of the plasma response in a spherical torus to such external perturbations.
Enhancing the low temperature hydrogen sensitivity of nanocrystalline SnO2 as a function of trivalent dopants
Authors: Drake C. , Amalu A. , Bernard J. , Seal S.
Published: May 2007

The effect of different indium doping concentrations on the room temperature hydrogen sensitivity of nano-SnO2 is investigated. The role of calcination temperature on the surface morphology, phase transformation, and subsequent impact on the gas sensing behavior of nanocrystalline doped SnO2 is presented. Differences in grain growth with varying doping amount give an explanation for enhanced sensing that is not always so obvious. Variation in the charge carrier density for indium doped nanocrystalline SnO2 is calculated as a function of indium concentration in the tin oxide lattice structure. The charge carrier density is correlated to the involved surface species of doped nanocrystalline SnO2 upon hydrogen gas exposure using Fourier transform infrared spectroscopy.
Characterization of excitonic features in self-assembled InAs/GaAs quantum dot superlattice structures via surface photovoltage spectroscopy
Authors: Chan C. H. , Lee C. H. , Huang Y. S. , Wang J. S. , Lin H. H.
Published: May 2007

This work systematically investigates the influence of InAs growth conditions and superlattice parameters on the optical properties of InAs/GaAs quantum dot (QD) superlattice structures grown by molecular beam epitaxy. Using surface photovoltage spectroscopy, one directly obtains the absorption spectra up to the highest confined QD levels at room temperature. Based on photoluminescence measurements at different excitation wavelengths, a feature below the fundamental transition is attributed to the transition from uncoupled dots in the bottom layers. The QD transition energy shift was found to be correlated with material intermixing, driven by enhanced strain strength with the increase of layer number and the decrease of spacer thickness, and the growth rate of InAs. A blueshift observed in low growth rate samples is indicative of greatly enhanced intermixing. For QD superlattices grown at a relatively high deposition rate of InAs, the material intermixing effect is gradually enhanced with increasing layer numbers, which will compensate the electronically coupled effect and will prevent further energy shift toward the lower energy side. The absorption wavelengths in 10- and 30-period InAs/GaAs QD superlattices with higher growth rates are near 1.32 μm. The results suggest that these QD superlattice structures can be used as promising active media for long-wavelength QD lasers operating at room temperature.
Absorption and scattering of light by Pt, Pd, Ag, and Au nanodisks: Absolute cross sections and branching ratios
Authors: Langhammer Christoph , Kasemo Bengt , Zorić Igor
Published: May 2007

Localized surface plasmons (LSPs) of metallic nanoparticles decay either radiatively or via an electron-hole pair cascade. In this work, the authors have experimentally and theoretically explored the branching ratio of the radiative and nonradiative LSP decay channels for nanodisks of Ag, Au, Pt, and Pd, with diameters D ranging from 38to530nm and height h=20nm, supported on a fused silica substrate. The branching ratio for the two plasmon decay channels was obtained by measuring the absorption and scattering cross sections as a function of photon energy. The former was obtained from measured extinction and scattering coefficients, using an integrating sphere detector combined with particle density measurements obtained from scanning electron microscopy images of the nanoparticles. Partly angle-resolved measurements of the scattered light allowed the authors to clearly identify contributions from dipolar and higher plasmonic modes to the extinction, scattering, and absorption cross sections. Based on these experiments they find that absorption dominates the total scattering cross section in all the examined cases for small metallic nanodisks (D<100nm). For D>100nm absorption still dominates for Pt and Pd nanodisks, while scattering dominates for Au and Ag. A theoretical approach, where the metal disks are approximated as oblate spheroids, is used to account for the trends in the measured cross sections. The field problem is solved in the electrostatic limit. The spheroid is treated as an induced dipole for which the dipolar polarizability is calculated based on spheroid geometry and the (bulk) dielectric response function of the metal the spheroid consists of and the dielectric medium surrounding it. One might expect this model to be inappropriate for disks with D>100nm since effects due to the retardation of the incoming field across the metallic nanodisk and contributions from higher plasmonic modes are neglected. However, this model describes quite well the energy dependence of the dipolar resonance, the full width at half maximum, and the total extinction cross section for all four metallic systems, even when 100<D<500nm, indicating that the combined contribution of the effects not included in the model is small for the systems studied. For this reason the authors have extended the use of the same model to study scattering/absorption branching ratios. The main conclusions include the following. (i) Both the magnitude and peak position in extinction cross section are well accounted for by the model. (ii) The branching ratio for radiative and nonradiative decay is reasonably well accounted for. (iii) The model fails to account for the correct magnitudes of the measured absorption and scattering cross sections for larger particles in the case of Ag and Au. Possible reasons for this discrepancy are discussed.
Shock formation processes in colliding two collisionless plasmas in a magnetic field
Authors: Yamauchi Koji , Ohsawa Yukiharu
Published: May 2007

Interactions of exploding and surrounding plasmas are analyzed with theory and particle simulations for the case in which the initial velocity v0 of the exploding plasma is perpendicular to the weak external magnetic field B0; because of the fast v0 and weak B0, the gyroradius v0∕Ωi is much longer than shock widths. After the penetration of the exploding ions, the electric field induced by the cross-field plasma motion quickly accelerates the surrounding ions in the direction perpendicular to v0 and B0. Owing to the magnetic force, however, the surrounding ions that were once overtaken by the exploding ions can pass them later. Because the electron guiding centers move with the E×B drift, the two kinds of electrons are not mixed. Further, because of the deceleration of the exploding ions in the front layer, the plasma density and magnetic-field strength go up there. This field reflects the surrounding ions forward and exploding ions backward. This generates two large pulses, which then develop into forward and reverse shock waves. Up to the generation of the two pulses, the time and length scales are basically determined by v0 and B0.
Comparison of proton conduction in KTaO3 and SrZrO3
Authors: Gomez Maria A. , Jindal Saryu , Fletcher Katharyn M. , Foster Leigh S. , Addo Nanna Dufie A. , Valentin Debbie , Ghenoiu Cristina , Hamilton Abigail
Published: May 2007

In the present paper, the authors focus on proton conduction pathways in a cubic perovskite KTaO3 and an orthorhombic perovskite SrZrO3. Density functional theory with a generalized gradient approximation is used to find proton binding sites. The nudged elastic band method is used to find transition states between minima. With this potential energy map of binding and transition states, adjacency matrices and their analogs identify four types of conduction paths in KTaO3. Distortions from these paths are seen in SrZrO3. In both cases, the lowest energy path has an intraoctahedral transfer rate-limiting barrier. A Fourier analysis of the OH stretch in ab initio molecular dynamics simulations revealed a strongly redshifted OH stretch in SrZrO3 relative to KTaO3. Hence, an orthorhombic system with a lowest energy conduction path limited by an intraoctahedral barrier can exhibit a redshifted OH stretch.
Ion transport and selectivity in nanopores with spatially inhomogeneous fixed charge distributions
Authors: Ramírez Patricio , Gómez Vicente , Cervera Javier , Schiedt Birgitta , Mafé Salvador
Published: May 2007

Polymeric nanopores with fixed charges show ionic selectivity when immersed in aqueous electrolyte solutions. The understanding of the electrical interaction between these charges and the mobile ions confined in the inside nanopore solution is the key issue in the design of potential applications. The authors have theoretically described the effects that spatially inhomogeneous fixed charge distributions exert on the ionic transport and selectivity properties of the nanopore. A comprehensive set of one-dimensional distributions including the skin, core, cluster, and asymmetric cases are analyzed on the basis of the Nernst-Planck equations. Current-voltage curves, nanopore potentials, and transport numbers are calculated for the above distributions and compared with those obtained for a homogeneously charged nanopore with the same average fixed charge concentration. The authors have discussed if an appropriate design of the spatial fixed charge inhomogeneity can lead to an enhancement of the transport and selectivity with respect to the homogeneous nanopore case. Finally, they have compared the theoretical predictions with relevant experimental data.
Study on the structural relationship between the liquid and amorphous Fe78Si9B13 alloys by ab initio molecular dynamics simulation
Authors: Qin Jingyu , Gu Tingkun , Yang Lei , Bian Xiufang
Published: May 2007

The structure of the liquid and amorphous Fe78Si9B13 alloys is investigated by ab initio molecular dynamics simulation. The amorphous structure bears a strong resemblance to the liquid structure on both the atomic and electronic levels. Chemical short-range order is evidenced by higher Fe coordinating proportion than the nominal one around both Si and B atoms in both the liquid and amorphous states. The atomic distances and the local densities of states show that Fe–Si bonding is stronger than Fe–B bonding and Si and B tend to repulse each other.
Direct observation of the vortex core magnetization and its dynamics
Authors: Chou K. W. , Puzic A. , Stoll H. , Dolgos D. , Schütz G. , Van Waeyenberge B. , Vansteenkiste A. , Tyliszczak T. , Woltersdorf G. , Back C. H.
Published: May 2007

Square-shaped thin film structures with a single magnetic vortex were investigated using a scanning transmission x-ray microscope. The authors report on the direct observation of the vortex core in 500×500nm2, 40nm thick soft magnetic Ni–Fe samples. The static configuration of the vortex core was imaged as well as the gyrotropic motion of the core under excitation with an in-plane alternating magnetic field. This enabled them to directly visualize the direction of the out-of-plane magnetization in the vortex core (up or down). The reversal of the core was effected by short bursts of an alternating magnetic field. An asymmetry appears in the core’s trajectory for its orientation pointing up and down, respectively.
Vibration-induced Cassie-Wenzel wetting transition on rough surfaces
Authors: Bormashenko Edward , Pogreb Roman , Whyman Gene , Bormashenko Yelena , Erlich Mordechai
Published: May 2007

The wetting transition is revealed for a water drop placed on a honeycomb polymer pattern under the action of vibration. Water penetration into the pattern cavities is accompanied by a change in the apparent contact angle. The Cassie-Wenzel wetting transition is confirmed by the model calculation. The threshold pressure in the drop for this transition is determined.
36-segmented high magnetic field hexapole magnets for electron cyclotron resonance ion source
Authors: Sun L. T. , Zhao H. W. , Zhang Z. M. , Wang H. , Ma B. H. , Zhang X. Z. , Li X. X. , Feng Y. C. , Li J. Y. , Guo X. H. , Shang Y. , Zhao H. Y.
Published: May 2007

Two high magnetic field hexapoles for electron cyclotron resonance ion source (ECRIS) have successfully fabricated to provide sufficient radial magnetic confinement to the ECR plasma. The highest magnetic field at the inner pole tip of one of the magnets exceeds 1.5T, with the inner diameter (i.d.)=74mm. The other hexapole magnet provides more than 1.35T magnetic field at the inner pole tip, and the i.d. is 84mm. In this article, we discuss the necessity to have a good radial magnetic field confinement and the importance of a Halbach hexapole to a high performance ECRIS. The way to design a high magnetic field Halbach structure hexapole and one possible solution to the self-demagnetization problem are both discussed. Based on the above discussions, two high magnetic field hexapoles have been fabricated to be utilized on two high performance ECRISs in Lanzhou. The preliminary results obtained from the two ECR ion sources are given.
Tactual, Visual, and Cross-Modal Transfer of Texture in 5- and 8-Year-Old Children
Authors: Picard Delphine
Published: May 2007

Children's tactual, visual, and cross-modal transfer abilities for texture were investigated in a delayed matching-to-sample paradigm. Transfer performance from vision to touch was found to increase between 5 and 8 years of age, whereas transfer performance from touch to vision did not vary with age and matched touch-to-touch performance. Asymmetrical cross-modal abilities were observed at the age of 8 years, vision-to-touch transfer performance being higher than touch-to-vision transfer performance (experiment 2). This developmental pattern could not be attributed to limitations in the tactual or visual discriminability of the textures or to differences in tactual or visual memory between the two age groups (experiment 1). It is suggested that the increase with age in vision-to-touch performance may be related to the intervention of more efficient top – down perceptual processes in the older children.
Structural insights into the bactericidal mechanism of human peptidoglycan recognition proteins
Authors: Cho Sangwoo , Wang Qian , Swaminathan Chittoor P. , Hesek Dusan , Lee Mijoon , Boons Geert-Jan , Mobashery Shahriar , Mariuzza Roy A.
Published: May 2007

Peptidoglycan recognition proteins (PGRPs) are highly conserved pattern-recognition molecules of the innate immune system that bind bacterial peptidoglycans (PGNs), which are polymers of alternating
N
-acetylglucosamine (NAG) and
N
-acetylmuramic acid (NAM) cross-linked by short peptide stems. Human PRGPs are bactericidal against pathogenic and nonpathogenic Gram-positive bacteria, but not normal flora bacteria. Like certain glycopeptide antibiotics (e.g., vancomycin), PGRPs kill bacteria by directly interacting with their cell wall PGN, thereby interfering with PGN maturation. To better understand the bactericidal mechanism of PGRPs, we determined the crystal structure of the C-terminal PGN-binding domain of human PGRP-Iβ in complex with NAG-NAM-
l
-Ala-γ-
d
-Glu-
l
-Lys-
d
-Ala-
d
-Ala, a synthetic glycopeptide comprising a complete PGN repeat. This structure, in conjunction with the previously reported NMR structure of a dimeric PGN fragment, permitted identification of major conformational differences between free and PGRP-bound PGN with respect to the relative orientation of saccharide and peptide moieties. These differences provided structural insights into the bactericidal mechanism of human PGRPs. On the basis of molecular modeling, we propose that these proteins disrupt cell wall maturation not only by sterically encumbering access of biosynthetic enzymes to the nascent PGN chains, but also by locking PGN into a conformation that prevents formation of cross-links between peptide stems in the growing cell wall.