bluuebunny/crossref_metadata_2025 huggingface dataset:
Raman spectroscopy study of ferroelectric modes in [001]-oriented 0.67Pb(Mg1∕3Nb2∕3)O3–0.33PbTiO3 single crystals
Authors: Shen Mingrong , Siu G. G. , Xu Z. K. , Cao Wenwu
Published: July 2005

This work investigates the evolution of micro-Raman spectra of a [001]-oriented 0.67Pb(Mg1∕3Nb2∕3)O3–0.33PbTiO3 single crystal in the temperature range from −120 to 200 °C. For a poled sample, the T1u mode splits into an E mode (remaining at 51cm−1) and a new A1 mode (shifting to 95cm−1 at −120°C) at the tetragonal to rhombohedral phase transition (Tc∼70°C), while other modes remain the same. This A1 mode belongs to the rhombohedral phase. If the sample is depoled, this A1 mode persists for temperatures much above Tc on heating, implying that local regions with rhombohedral symmetry still exist in the tetragonal phase. The underdevelopment of long-range order in the depoled crystal causes the sample to have typical characteristics of a relaxor while poling will enhance the long-range order to make it into a regular ferroelectric.
Valence band structure of ultrathin silicon and germanium channels in metal-oxide-semiconductor field-effect transistors
Authors: Low Tony , Li M. F. , Yeo Y. C. , Fan W. J. , Ng S. T. , Kwong D. L.
Published: July 2005

The ultrathin body (UTB) silicon-on-insulator metal-oxide-semiconductor field-effect transistor (MOSFET) is promising for sub-50-nm complementary metal-oxide semiconductor technologies. To explore a high-mobility channel for this technology, this paper presents an examination of Si and Ge hole sub-band structure in UTB MOSFETs under different surface orientations. The dependence of the hole subband structure on the film thickness (TBody) was also studied in this work. We found that the valence-band mixing in the vicinity of the zone center Γ is strongly dependent on TBody for both Si and Ge, particularly for the ⟨110⟩ surface orientation. This gives rise to the following two phenomena that crucially affect the electrical characteristics of p-MOSFETs: (1) an anomalous increase of quantization mass for ⟨110⟩ Si and Ge surfaces as TBody is scaled below 5nm. (2) The dependence of energy dispersion and anisotropy on TBody especially for the ⟨110⟩ surface, which advantageously increases hole velocity along the [011] channel as TBody is decreased. The density of states for different surface orientations are also calculated, and show that—for any given surface orientation—Ge has a smaller density of states than Si. The Ge ⟨110⟩ surface has the lowest density of states among the surface orientations considered.
The role of counterions on the elasticity of highly charged lamellar phases: A small-angle x-ray and neutron-scattering determination
Authors: Brotons Guillaume , Dubois Monique , Belloni Luc , Grillo Isabelle , Narayanan Theyencheri , Zemb Thomas
Published: July 2005

The structure and fluctuations of the swollen Lα lamellar phase of highly charged surfactant didodecyldimethylammonium halide fluid bilayers (DDA+X−) are studied using high-resolution small-angle x-ray scattering and medium-resolution, high-contrast small-angle neutron-scattering. The Caillé parameter η, as a function of the swelling (Lα periodicity d), was determined from the full q-range fits of the measured scattering profiles for three different counterions (X−=Cl−, Br−, and NO3−). This parameter quantifies the amplitude of the membrane fluctuations within the Landau–de Gennes smectic-A linear elasticity theory. The different anions used gave strong specific effects at the maximum swelling of the Lα phase, while at lower swellings a two-phase coexistence of swollen and collapsed lamellae (d∼30 and ∼80Å) was observed for bromide and nitrate ions. Over the intermediate dilution range for all three counterions, a single Lα phase can be continuously swollen with pure water which is governed by an equation of state (i.e., osmotic pressure versus period) and thermally excited fluctuation amplitudes that can be well described by the same Poisson–Boltzmann calculation. The membranes were found to be slightly stiffer than predicted by purely electrostatic repulsions, and this is tentatively attributed to an extra bending rigidity contribution from the surfactant chains.
Universality of thermally assisted magnetic domain-wall motion under spin torque
Authors: Tatara Gen , Vernier Nicolas , Ferré Jacques
Published: July 2005

Thermally assisted motion of magnetic domain wall under spin torque is studied theoretically. It is shown that the wall velocity v depends exponentially on the spin current, Is, below the threshold value, in the same way as in a thermally activated motion driven by a force. A significant property of the spin torque driven case at low temperature is that the linear term in spin current is universal, i.e., Inv∼πℏ∕2e(Is∕kBT). This behavior, which is independent of pinning and material constants, could be used to confirm experimentally the spin torque as the driving mechanism.
Anisotropic dipole polarizability of transition metal atoms: Sc(D2), Ti(F3,P3), V(F4,P4,D6), Ni(F3) and ions: Sc2+(D2), Ti2+(F3,P3)
Authors: Kłos J.
Published: July 2005

Dipole polarizability tensor components and quadrupole moments of transition-metal atoms Sc, Ti, V, Ni, and Cu and ions Sc2+ and Ti2+ are computed using finite field complete active space self-consistent field and multireference configuration interaction ab initio methods. Perpendicular components of the dipole polarizability tensor are calculated from equations involving only parallel components of the polarizability tensor and its average value. Mean polarizability and polarizability anisotropy decrease in the Sc–Ni series. Relativistic effects are accounted for with the Douglas-Kroll Hamiltonian. The consequences of the anisotropic properties of these atoms to their interactions with spherically symmetric rare gases are also discussed.
Effect of polymer chain in coexisting liquid phases by refractive index measurements
Authors: Venkatesu Pannur
Published: July 2005

The behavior of polyethylene oxide (PEO, molecular weight, Mw=9×105, as an impurity) was studied in the critical binary mixture of nitroethane (NE)+3-methylpentane (MP) by refractive index measurements. The measurements were performed at three different PEO concentrations (C=0.373, 0.759, and 1.509mg∕cc) in the near critical composition of NE∕MP. We observed that the coexisting phase region shifts down with increasing PEO concentration and the critical temperature (Tc) decreases linearly with C. At temperatures T close enough to Tc, the critical exponent β [defined by the relation (n1−n2)∝(Tc−T)β, with n1 and n2 being the refractive indices of the coexisting phases] was found to decrease from 0.456 to 0.372 when the PEO concentration changes from 0.373to1.509mg∕cc. These values are higher than that of 0.345±0.015 of pure NE∕MP, which is compatible with the three-dimensional Ising value β=0.325. It appears that the shape of the PEO in NE∕MP coexistence curves is similar from that of pure NE+MP.
Influence of gate-leakage current on drain current collapse of unpassivated GaN∕AlGaN∕GaN high electron mobility transistors
Authors: Kordoš P. , Bernát J. , Marso M. , Lüth H. , Rampazzo F. , Tamiazzo G. , Pierobon R. , Meneghesso G.
Published: July 2005

We report on a correlation between the gate leakage currents and the drain current collapse of GaN∕AlGaN∕GaN high electron mobility transistors. Unpassivated devices on intentionally undoped and doped (Si, 5×1018cm−3) heterostructures were investigated. We observed in the devices that the larger the gate leakage current, the smaller the drain current collapse measured at 50ns gate-voltage pulse turn on, and this correlation is independent of the doping of the structure. The correlation holds for two orders of magnitude in the gate-leakage current and up to 15% in drain current collapse. We believe that the leakage current can modulate trapped surface charge so that the time constant of the current collapse becomes much faster and dependent on the amount of leakage current itself.
Time dependence of delayed neutron emission for fissionable isotope identification
Authors: Kinlaw M. T. , Hunt A. W.
Published: July 2005

The time dependence of delayed neutron emission was examined as a method of fissionable isotope identification. A pulsed bremsstrahlung photon beam was used to induce photofission reactions in U238, Th232, and Pu239 targets. The resulting delayed neutron emission was recorded between irradiating pulses and is a well-known technique for fissionable material detection. Monitoring the decay of delayed neutron emission between irradiating pulses demonstrates the ability to not only detect the presence of fissionable materials, but also to identify which fissionable isotope is present.
Role of titanium in hydrogen desorption in crystalline sodium alanate
Authors: Araújo C. Moysés , Ahuja Rajeev , Osorio Guillén J. M. , Jena Puru
Published: July 2005

The role of Ti in improving the thermodynamics of hydrogen desorption in crystalline sodium alanate (NaAlH4) has been investigated by using the density functional theory. The total energy calculations reveal that Ti prefers to occupy the Na site over that of the Al site when the atomic energies are used as the reference. However, the use of the cohesive energies of Al, Na, and Ti leads to the Al site being the least unfavorable one. Irrespective of whether Ti occupies the Na or the Al site, the energy necessary to remove a hydrogen atom from Ti substituted sodium alanate is significantly lowered from that of the pure alanate. The understanding gained here may help in designing hydrogen storage materials suitable for industrial applications.
Internal electric-field and segregation effects on luminescence properties of quantum wells
Authors: Gonzalez de la Cruz G. , Calderon Arenas A. , Herrera H.
Published: July 2005

Surface segregation of In atoms during molecular-beam epitaxy and its influence on the energy levels in strained piezoelectric InGaAs∕GaAs and InGaN∕GaN quantum wells (QWs) are investigated theoretically. It is shown that these effects modify the electronic states in the QW and the emission energy in the photoluminescence (PL) spectra. In this work, we solve analytically the Schrödinger equation in the absence of electric field, taking into account the shape changes in the QWs due to the segregation of In atoms during the growth process of the semiconductor heterostructures. Furthermore, the influence of the built-in electric field due to the piezoelectric effect on the PL emission is calculated by considering a variational electron wave function to calculate the ground-energy transitions inside the active region in the heterostructure. In particular, we apply this model to the case of indium segregation in InGaAs∕GaAs for moderate internal electric fields. The transition energy calculations between the confined electron and hole states as a function of the well width for different temperatures and In composition are in agreement with the measured PL energy peaks.
A method to enhance the data transfer rate of eutectic Sb-Te phase-change recording media
Authors: Yeh Tung-Ti , Hsieh T.-E. , Shieh Han-Ping D.
Published: July 2005

This work describes the effect of nitrogen doping to eutectic Sb-Te phase-change materials in order to enhance the speed of the amorphous-to-crystalline phase transformation. When nitrogen at a sputtering gas flow ratio of N2/Ar=3% was doped in the eutectic Ge-In-Sb-Te recording layer, the data transfer rate was increased up to 1.6 times. When thin GeNx nucleation promotion layers were further added in below and above the recording layer, an overall enhancement up to 3.3 times in data transfer rate was achieved. The nitrogen contents corresponding to the N2/Ar flow ratios (N2∕Ar=0%–10%) were calibrated by electron spectroscopy for chemical analysis. Transmission electron microscopy revealed that nitrogen doping was able to promote the phase transformation by generating numerous nucleation sites uniformly distributed in the recording layer and hence increased the recrystallization speed.
Self-assembly of periodic ZnO/C multilayers on Zn nanowires
Authors: Kwong K. W. , Li Quan
Published: July 2005

In a previous study, we observed periodic polycrystalline-ZnO∕amorphous-C multilayers self-organized on the surface of Zn nanowires, which were dispersed on the amorphous carbon film at ambient conditions after 1500 h. Such self-assembled multilayers with individual layer thickness of ≃2nm have been reproduced through a simple chemical reaction between the Zn nanowires and the CO2 gas. Transmission electron microscopy is employed to investigate the evolution of the Zn nanowire during its reaction with the CO2. A systematic study is carried out and a four-step mechanism—gas phase diffusion, interfacial chemical reaction, phase separation, and self-alignment—is proposed to explain the formation of such nanostructures. The parameters that affected the self-assembly process including the crystallinity of the original native zinc oxide sheath wrapping the Zn nanowires, the reaction temperature, and the reacting gases are discussed in detail based on the experimental observations.
Unexpectedly high sputtering yield of carbon at grazing angle of incidence ion bombardment
Authors: Barna A. , Menyhard M. , Kotis L. , Kovacs Gy. J. , Radnoczi G. , Zalar A. , Panjan P.
Published: July 2005

The relative sputtering yield of amorphous carbon with respect to polycrystalline nickel at Ar-ion bombardment was determined by means of Auger electron spectroscopy depth profiling as a function of the angle of incidence and projectile energy in the ranges of 49°–88° and 0.3–1keV, respectively. It was found that the relative sputtering yield YC∕YNi strongly increases with angle of incidence from 49° to 82°. At around 80° the sputtering yield of C is higher than that of Ni. Above 82° no dependence on the angle of incidence was found. The relative sputtering yield weakly depends on the energy of the projectile. The experimental results will be explained by the help of transport of ion in solid (TRIM) simulations.
Temperature and electric-field dependences of hole mobility in light-emitting diodes based on poly [2-methoxy-5-(2-ethylhexoxy)-1,4-phenylene vinylene]
Authors: Kumar Amit , Bhatnagar P. K. , Mathur P. C. , Husain M. , Sengupta Sandip , Kumar Jayant
Published: July 2005

The current-voltage characteristics of poly [2-methoxy-5-(2-ethylhexoxy)-1,4-phenylene vinylene] (MEH-PPV)-based hole-only light-emitting diodes are measured as a function of temperature. The hole current is found to be space-charge limited, providing a direct measure of the mobility as a function of temperature and electric field. A thermal activation energy of 0.2eV is obtained for the zero-field mobility, with a room-temperature low-field mobility value for holes of 3.3×10−7cm2∕Vs. The hole mobility exhibits field dependence in accordance with the Poole-Frenkel effect. The combination of space-charge effects and field-dependent mobility thus provides a consistent description of hole transport as a function of temperature and bias voltage in MEH-PPV films.
Morphology-dependent electric transport in textured ultrathin Al films grown on Si
Authors: Aswal D. K. , Joshi Niraj , Debnath A. K. , Muthe K. P. , Gupta S. K. , Yakhmi J. V. , Vuillaume Dominique
Published: July 2005

The thickness and temperature dependence of the electrical resistivity of the (111) textured ultrathin aluminum metal films grown on (111) Si substrates using molecular-beam epitaxy have been investigated. For films with thickness <50nm, the room-temperature value of resistivity—contrary to the predictions of existing theoretical models—is found to increase monotonically with thickness. In addition, the temperature dependence of these films exhibited a metal-to-insulator transition at ∼110K. The studies of films using atomic force microscopy, x-ray photoelectron spectroscopy, and x-ray diffraction revealed that the observed anomalous thickness and temperature dependence of resistivity arise due to the formation of two-dimensional network of Al islands, and the low-temperature electric transport of such films could be explained using variable range hopping conduction.
Physics of patterned magnetic medium recording: Design considerations
Authors: E Chunsheng , Smith Darren , Wolfe Jack , Weller Dieter , Khizroev Sakhrat , Litvinov Dmitri
Published: July 2005

Selected aspects of the recording physics of magnetic data storage systems based on patterned medium are discussed. Considerations for the choice of a recording layer material are outlined. A micromagnetic study of magnetization reversal in patterned magnetic recording medium is presented. The effects of bit geometry, medium thickness, head/medium magnetic spacing, air-bearing surface geometry, write pole material, and write misregistration on magnetization reversal are explored. The influence of a recording layer design on playback resolution is evaluated. The results offer the guidelines for the design and optimization of patterned magnetic recording medium.
Thermally activated carrier transfer processes in InGaN∕GaN multi-quantum-well light-emitting devices
Authors: Yang C. L. , Ding L. , Wang J. N. , Fung K. K. , Ge W. K. , Liang H. , Yu L. S. , Qi Y. D. , Wang D. L. , Lu Z. D. , Lau K. M.
Published: July 2005

We have studied the temperature-dependent carrier transfer processes in InGaN∕GaN multi-quantum-well light-emitting devices using various optical techniques such as photoluminescence, electroluminescence, and photoluminescence excitation spectra. The role of the defects in the GaN barrier neighboring to the InGaN region was demonstrated clearly in capturing carriers only at low temperatures. The physical origin of the defects was most possibly attributed to the stacking faults at the interface according to the high-resolution transmission electron spectroscopy pictures.
Observation of the c̃A11 state of methylene by optical-optical double resonance
Authors: Kim Yangsoo , Komissarov Anatoly V. , Hall Gregory E. , Sears Trevor J.
Published: July 2005

We report the observation of the rotationally resolved spectrum of the c̃A11 state of CH2 via sequential single-photon absorptions at visible and near-infrared wavelengths. Direct absorption from the lowest singlet state ãA11 to c̃A11 occurs in the near UV, but it is weak because it corresponds to a two electron transition between the dominant single configuration approximations to the electronic wave functions. Some absorption lines in the c̃-ã system were originally reported in 1966 [G. Herzberg and J. W. C. Johns, Proc. R. Soc. London, Ser. A 295, 107 (1966)], but the weak spectra could not be assigned at the time. Interest in the c̃A11 state was rekindled by recent ab initio results [S. N. Yurchenko, P. Jensen, Y. Li, R. J. Buenker, and P. R. Bunker, J. Mol. Spectrosc. 208, 136 (2001)] which prompted the present work. The new spectra provide accurate energies for rotational levels in the v2linear=11,l=1 level of the state, and permit assignment of most of the line positions measured by Herzberg and Johns. The double-resonance technique used may be easily extended to the measurement of lower rovibrational levels in the electronic state and possibly also to access the d̃A21 state which is theoretically expected to lie at similar energies but, for symmetry reasons, is not accessible from the lowest singlet state in a single electric-dipole transition.
Mechanism of the temperature sensitivity of mid-infrared GaSb-based semiconductor lasers
Authors: Suchalkin S. , Shterengas L. , Kisin M. , Luryi S. , Belenky G. , Kaspi R. , Ongstad A. , Kim J. G. , Martinelli R. U.
Published: July 2005

The sources of temperature sensitivity of the threshold current in type-I and type-II mid-infrared semiconductor lasers are investigated. Measurements of the interband optical absorption allow direct comparison of the optical matrix elements in laser structures with type-I and type-II band alignments and prove that the difference in the optical matrix elements is insignificant for these two groups of structures. We show that thermally-induced hole escape from the active quantum wells strongly deteriorates the optical emission in both type heterostructures. Experiments show that the temperature decay of PL is generally stronger for type-II samples.
Achieving 280fs resolution with a streak camera by reducing the deflection dispersion
Authors: Shakya Mahendra Man , Chang Zenghu
Published: July 2005

The factors that limit the temporal resolution in a streak camera operating in an accumulative mode were studied. By controlling the timing jitter, the transit-time dispersion and the technical resolution of the camera on the order of 100fs, the role of the deflection dispersion was investigated experimentally. It was done by changing the electron beam size in the deflection plates with a variable slit in front of the plates. The temporal resolution of the camera reached 280fs when the slit width was a 5μm slit.
Meiotic telomere clustering requires actin for its formation and cohesin for its resolution
Authors: Trelles-Sticken Edgar , Adelfalk Caroline , Loidl Josef , Scherthan Harry
Published: July 2005

In diploid organisms, meiosis reduces the chromosome number by half during the formation of haploid gametes. During meiotic prophase, telomeres transiently cluster at a limited sector of the nuclear envelope (bouquet stage) near the spindle pole body (SPB). Cohesin is a multisubunit complex that contributes to chromosome segregation in meiosis I and II divisions. In yeast meiosis, deficiency for Rec8 cohesin subunit induces telomere clustering to persist, whereas telomere cluster–SPB colocalization is defective. These defects are rescued by expressing the mitotic cohesin Scc1 in rec8Δ meiosis, whereas bouquet-stage exit is independent of Cdc5 pololike kinase. An analysis of living Saccharomyces cerevisiae meiocytes revealed highly mobile telomeres from leptotene up to pachytene, with telomeres experiencing an actin- but not microtubule-dependent constraint of mobility during the bouquet stage. Our results suggest that cohesin is required for exit from actin polymerization–dependent telomere clustering and for linking the SPB to the telomere cluster in synaptic meiosis.
SNAREs can promote complete fusion and hemifusion as alternative outcomes
Authors: Giraudo Claudio G. , Hu Chuan , You Daoqi , Slovic Avram M. , Mosharov Eugene V. , Sulzer David , Melia Thomas J. , Rothman James E.
Published: July 2005

Using a cell fusion assay, we show here that in addition to complete fusion SNAREs also promote hemifusion as an alternative outcome. Approximately 65% of events resulted in full fusion, and the remaining 35% in hemifusion; of those, approximately two thirds were permanent and approximately one third were reversible. We predict that this relatively close balance among outcomes could be tipped by binding of regulatory proteins to the SNAREs, allowing for dynamic physiological regulation between full fusion and reversible kiss-and-run–like events.
Actin- and myosin-driven movement of viruses along filopodia precedes their entry into cells
Authors: Lehmann Maik J. , Sherer Nathan M. , Marks Carolyn B. , Pypaert Marc , Mothes Walther
Published: July 2005

Viruses have often been observed in association with the dense microvilli of polarized epithelia as well as the filopodia of nonpolarized cells, yet whether interactions with these structures contribute to infection has remained unknown. Here we show that virus binding to filopodia induces a rapid and highly ordered lateral movement, “surfing” toward the cell body before cell entry. Virus cell surfing along filopodia is mediated by the underlying actin cytoskeleton and depends on functional myosin II. Any disruption of virus cell surfing significantly reduces viral infection. Our results reveal another example of viruses hijacking host machineries for efficient infection by using the inherent ability of filopodia to transport ligands to the cell body.
Decoding Ca2+ signals
Authors: Muallem Shmuel
Published: July 2005

Receptor-stimulated Ca2+ signals come in several flavors. The Ca2+ signals can be decoded linearly or by integration of the response. How the duration of the signal conveyed by cytosolic Ca2+ concentration ([Ca2+]i) changes is regulated is not well understood. Liu et al. (Liu, Q., S.A. Walker, D. Gao, J.A. Taylor, Y.-F. Dai, R.S. Arkell, M.D. Bootman, H.L. Roderick, P.J. Cullen, and P.J. Lockyer. 2005. J. Cell Biol. 170:183–190) now report an example of decoding based on the differential regulation of Ras function by two Ca2+-sensitive Ras inhibitors: Ca2+-promoted Ras activator (CAPRI), which extends the duration of the effect of Ca2+ on Ras activity, and Ras GTPase activating-like protein (RASAL), which functions as a linear decoder of the Ca2+ signal.
Toll-like receptor 9 controls anti-DNA autoantibody production in murine lupus
Authors: Christensen Sean R. , Kashgarian Michael , Alexopoulou Lena , Flavell Richard A. , Akira Shizuo , Shlomchik Mark J.
Published: July 2005

Systemic autoimmune disease in humans and mice is characterized by loss of immunologic tolerance to a restricted set of self-nuclear antigens. Autoantigens, such as double-stranded (ds) DNA and the RNA-containing Smith antigen (Sm), may be selectively targeted in systemic lupus erythematosus because of their ability to activate a putative common receptor. Toll-like receptor 9 (TLR9), a receptor for CpG DNA, has been implicated in the activation of autoreactive B cells in vitro, but its role in promoting autoantibody production and disease in vivo has not been determined. We show that in TLR9-deficient lupus-prone mice, the generation of anti-dsDNA and antichromatin autoantibodies is specifically inhibited. Other autoantibodies, such as anti-Sm, are maintained and even increased in TLR9-deficient mice. In contrast, ablation of TLR3, a receptor for dsRNA, did not inhibit the formation of autoantibodies to either RNA- or DNA-containing antigens. Surprisingly, we found that despite the lack of anti-dsDNA autoantibodies in TLR9-deficient mice, there was no effect on the development of clinical autoimmune disease or nephritis. These results demonstrate a specific requirement for TLR9 in autoantibody formation in vivo and indicate a critical role for innate immune activation in autoimmunity.
Reciprocal regulation of airway rejection by the inducible gas-forming enzymes heme oxygenase and nitric oxide synthase
Authors: Minamoto Kanji , Harada Hiroaki , Lama Vibha N. , Fedarau Maksim A. , Pinsky David J.
Published: July 2005

Obliterative bronchiolitis (OB) develops insidiously in nearly half of all lung transplant recipients. Although typically preceded by a CD8+ T cell–rich lymphocytic bronchitis, it remains unresponsive to conventional immunosuppression. Using an airflow permissive model to study the role of gases flowing over the transplanted airway, it is shown that prolonged inhalation of sublethal doses of carbon monoxide (CO), but not nitric oxide (NO), obliterate the appearance of the obstructive airway lesion. Induction of the enzyme responsible for the synthesis of CO, heme oxygenase (Hmox) 1, increased carboxyhemoglobin levels and suppressed lymphocytic bronchitis and airway luminal occlusion after transplantation. In contrast, zinc protoporphyrin IX, a competitive inhibitor of Hmox, increased airway luminal occlusion. Compared with wild-type allografts, expression of inducible NO synthase (iNOS), which promotes the influx of cytoeffector leukocytes and airway graft rejection, was strikingly reduced by either enhanced expression of Hmox-1 or exogenous CO. Hmox-1/CO decreased nuclear factor (NF)-κB binding activity to the iNOS promoter region and iNOS expression. Inhibition of soluble guanylate cyclase did not interfere with the ability of CO to suppress OB, implicating a cyclic guanosine 3′,5′-monophosphate–independent mechanism through which CO suppresses NF-κB, iNOS transcription, and OB. Prolonged CO inhalation represents a new immunosuppresive strategy to prevent OB.
A malarial cysteine protease is necessary for Plasmodium sporozoite egress from oocysts
Authors: Aly Ahmed S.I. , Matuschewski Kai
Published: July 2005

The Plasmodium life cycle is a sequence of alternating invasive and replicative stages within the vertebrate and invertebrate hosts. How malarial parasites exit their host cells after completion of reproduction remains largely unsolved. Inhibitor studies indicated a role of Plasmodium cysteine proteases in merozoite release from host erythrocytes. To validate a vital function of malarial cysteine proteases in active parasite egress, we searched for target genes that can be analyzed functionally by reverse genetics. Herein, we describe a complete arrest of Plasmodium sporozoite egress from Anopheles midgut oocysts by targeted disruption of a stage-specific cysteine protease. Our findings show that sporozoites exit oocysts by parasite-dependent proteolysis rather than by passive oocyst rupture resulting from parasite growth. We provide genetic proof that malarial cysteine proteases are necessary for egress of invasive stages from their intracellular compartment and propose that similar cysteine protease–dependent mechanisms occur during egress from liver-stage and blood-stage schizonts.
Dendritic cell maturation by innate lymphocytes
Authors: Münz Christian , Steinman Ralph M. , Fujii Shin-ichiro
Published: July 2005

Pathogen recognition by Toll-like receptors (TLRs) on dendritic cells (DCs) leads to DC maturation and the initiation of adaptive immunity. Recent studies have shown that innate lymphocytes—natural killer (NK), natural killer T (NKT), and γδ T cells—also trigger DC maturation. This interaction in turn expands and activates innate lymphocytes and initiates adaptive T cell immunity. Here, we comment on the evidence that these pathways are TLR independent and have the potential to respond to infection, malignancy, and immunotherapy.
Dose‐response effects of inulin on the faecal short‐chain fatty acids content and mineral absorption of formula‐fed infants
Authors: Yap K.W. , Mohamed S. , Yazid A.M. , Maznah I. , Meyer D.M.
Published: July 2005

Purpose

The objective of this study is to examine the dose‐response effect of inulin on mineral absorption and faecal short‐chain fatty acids concentration in formula‐fed infants.

Design/methodology/approach

The effects of inulin on faecal short‐chain fatty acids and minerals absorption in 36 healthy, formula‐fed infants given three different doses of inulin (0.75g/d, 1.00g/d, and 1.25g/d) were studied using complete randomized design. Acetic, butyric, propionic and lactic acids were analysed using gas chromatography.

Findings

No significant (p<0.05) difference was observed in the infant faecal short‐chain fatty acids contents during the basal period, the intake period and the washout period. A significant (p<0.05) increase in per cent apparent absorption, per cent apparent retention and net retention of iron were seen in infants supplemented with 1g/day inulin. A significant (p<0.05) increase in per cent apparent retention and net retention of Magnesium was also seen in infants supplemented with 0.75, 1 and 1.25g/day inulin. A significant (p<0.05) increase in per cent apparent absorption and net retention of Zinc was seen in infants supplemented with only 0.75g/day inulin. No significant improvement in calcium, or copper absorption or retention was observed in all the doses of inulin studied.

Originality/value

Most previous studies were conducted on adults and adolescents.
Can Japanese mentoring enhance understanding of Western mentoring?
Authors: Iain Bright Mark
Published: July 2005

Purpose

Aims to illustrate how Japan possesses cultural characteristics to support mentoring as a relationship, as opposed to the West, whose favoured approach is to view mentoring as a strategy.

Design/methodology/approach

A comparative analysis of the mentoring literature from two world views; the Japanese mentoring context (primarily the senpai‐kohai relationship) is compared and contrasted with the Western mentoring context.

Findings

The US and European context for mentoring increasingly consists of formalised schemes, targeted at specific groups (such as the talented or socially disadvantaged), and forms a co‐ordinated activity of human resource departments. As Western organisations have changed, mentoring has become defined in strategic terms, and aligned with a variety of popular management theories. In contrast, Japanese views of mentoring are characterised by informality, organic growth of relationships at all organisational levels, and are based on emotional bonds between seniors and juniors.

Practical implications

A very useful source to explain why Western organisations find it difficult to establish mentoring relationships based on emotional bonds. The Japanese show that there is an alternative; one requiring many Western organisations to adapt their organisational cultures and re‐conceptualise their views of mentoring.

Originality/value

This paper brings together the few contributions by authors of the Japanese senpai‐kohai relationship (a form of mentoring exclusive to Japan). It compares a rarely examined context in the mentoring debate (i.e. Eastern views of mentoring) with the larger body of work examining mentoring in the West. Originality resides in the results of the comparative analysis, revealing one context which views mentoring as a relationship, and another which views mentoring as a strategy.
Gender differences in policing: signs of progress?
Authors: Burke Ronald J. , Mikkelsen Aslaug
Published: July 2005

Purpose

This exploratory study aims to compare job demands, work outcomes, social and coping resources and indicators of psychological and physical health of male and female police officers in Norway.

Design/methodology/approach

Data were collected using anonymously completed questionnaires.

Findings

Many demographic differences were present in that male officers were older, worked more hours and overtime hours, were more likely to work continuous shiftwork, worked in smaller forces and were less educated. Few differences were found on job demands but male officers experienced more violence and threat, and female officers more harassment and discrimination. The two groups were generally similar on work satisfactions, social and coping resources and psychological and physical health.

Research limitations/implications

All data were collected using questionnaires raising the possibility of common method variance. It is also not clear extent to what these findings generalize to police officers in other countries.

Practical implications

While few differences were found between male and female police officers, the fact that females reported more harassment and discrimination suggests that police forces need to continue to address these gender issues.

Originality/value

While other studies of police officers have suggested widespread gender differences, few appeared here.
Interaction in a building owner centred network – case study
Authors: Tuomela Antti , Heimbürger Markku , Nummi Juha , Toivonen Jouko
Published: July 2005

Purpose

A case study at Senate Properties, a Finnish building owner organisation, for theory building was conducted to provide significant insights into strategic planning in partnership networks with a view to developing interaction in a triadic alliance. The purpose of this paper is to describe how a Finnish building owner organisation, Senate Properties, the focal firm of the studied network, manages multi‐level interaction in the alliance network of the case study.

Design/methodology/approach

In this paper, the building owner's role is studied by using two network analysis studies. The emergent phase of a “triadic alliance” of service providers, building owners as contract managers, and the end‐users of services is analysed by using two separate qualitative network analysis studies.

Findings

The case study indicates that the networks of building users, owners, facilities management parties and service providers can improve their interaction and cooperation by multilevel interaction building, mutual orientation building in groups and formation of boundary‐spanning roles. We therefore present a model or a framework for interaction building in triadic networks that is derived from a knowledge base that can better explain the requirements of core businesses, key real estate and facilities services attributes and options evaluation to meet dynamic changes.

Research limitations/implications

The paper suggests that organisations involved in facilities management that enter into an alliance have to communicate and proactively exchange information to strengthen the interaction and cooperation between network members. For success, each network member should share information and each must learn from the others.

Originality/value

The interaction approach of network analysis takes place in a new building owner centred environment. The paper argues on a general level that to understand the complicated roles within the workplace environment, it is necessary to study the interaction needs of different functions.
Recruitment and retention of estates and facilities staff in the NHS
Authors: May Daryl , Askham Phil
Published: July 2005

Purpose

Agenda for Change is set to be the biggest reform of pay since the National Health Service (NHS) began in 1948. As well as introducing a standardised pay structure; it also aims to improve recruitment, retention and staff morale. Staff groups identified as having recruitment and retention problems include estates/works officers, qualified maintenance crafts persons and qualified maintenance technicians. The object of this research was to investigate recruitment and retention problems for estates and facilities staff currently experienced by Trusts.

Design/methodology/approach

Focus groups were used as the primary method of data collection in an attempt to tap into the existing expertise of staff working at strategic and operational supervisory positions in a wide range of Trusts.

Findings

Although our findings suggest that the main recruitment and retention issues fall into four main themes: social, financial, environmental and political; recruitment and retention of estates and facilities management staff is a complex problem involving a wide range of issues and these can vary from location to location. Furthermore this should also be seen as a series of issues that varies across employment groups including: domestic/housekeeping, trades, managers/officers and facilities directors, which need to be distinguished.

Practical implications

There is a continuing need to raise the profile of estates and facilities management staff in the NHS to those levels enjoyed by Human Resource (HR) and Financial Management. Furthermore perceptions surrounding both recruitment and retention issues and the nature of work within estates and facilities management staff in the NHS can lead to a negative and self‐perpetuating “cycle of failure” where there is an assumption of loss of control. However, there are some initiatives being undertaken that suggest it is possible to concentrate on internal matters such as more appropriate and flexible recruitment processes, improved support services for staff and greater flexibility within the job and that these can generate “cycles of success”.

Originality/value

The paper looks in‐depth at the current recruitment and retention problems for NHS estates and facilities staff. The paper would be of use to NHS estates and facilities managers who are currently investigating workforce issues, particularly surrounding recruitment and retention of staff.
Economic production quantity and process quality: a multivariate approach
Authors: Chan Weng M. , Ibrahim Raafat N. , Lochert Paul B.
Published: July 2005

Purpose

The purpose of this paper is to study the interaction of economics of production with process quality, when multiple key quality characteristics are present. Specifically, the paper aims to analyse the possibility of investing in a production process to reduce its variances and the impact on a multivariate quality loss function.

Design/methodology/approach

A bivariate inventory‐planning model is developed, in which the optimal investment for reducing process variances and the optimal lot size are jointly determined. A case study with industrial data is presented to illustrate the possible solution procedures and the potential advantages of the proposed model.

Findings

It is found that by using the previous approaches to analyse the interaction between the economics of production and process quality, a company will underestimate the cost of quality, especially the expected external failure cost (quality loss), and ultimately invest less into the prevention activities to improve the process.

Originality/value

The proposed model can help managers to compare different production processes and also guide the managers towards better choices for process improvement. To the best of our knowledge, this paper is the first to integrate the economic production quantity (EPQ) problem with the process quality consideration for products with multiple quality characteristics.
Magnetic force computation with hysteresis
Authors: Szabó Zs. , Füzi J. , Iványi A.
Published: July 2005

Purpose

The purpose of this paper is to present a procedure, which determines the magnetic force acting between a soft magnetic cylinder and a coil taking the hysteresis phenomena into account.

Design/methodology/approach

The magnetic force is computed replacing the ferromagnetic body with an equivalent magnetic moment distribution. Isotropic vector Preisach model with analytical expressed Everett function describes the magnetic properties of the ferromagnetic material. The magnetization distribution is calculated applying the integral equation method. The Preisach hysteresis model is included in the iteration process based on Picard‐Banach scheme.

Findings

In the case of integral equation method the unknown quantities are the magnetization and the magnetic field intensity. In this way the Preisach hysteresis model can be included in a convenient way in the iteration procedure. Knowing the magnetization distribution the magnetic force can be determined. The developed algorithms can be applied in tubular linear motor design.

Originality/value

The paper presents a new formulation of the Preisach hysteresis model. With the aim of the analytically expressed Everett function a stable and faster algorithm can be realized to determine the magnetic force in arrangements with ferromagnetic parts.
Regularization of inverse magnetostatic problems: possibilities and pitfalls
Authors: Formisano A.
Published: July 2005

Purpose

Inverse problems are usually ill‐conditioned, requiring the adoption of regularization techniques to obtain reliable results. The choice of the regularization method and of the related parameters represents a critical issue that must be based on the knowledge of reliable additional information on the problem. In the paper some possibilities and pitfalls for the choice of regularization strategy are presented and compared.

Design/methodology/approach

Electromagnetic inverse problems (EIP) are usually formulated starting from a direct problem, based on a direct operator, providing the effects (e.g. fields, fluxes) generated by known sources acting through known systems. The direct operators involved in many real world electromagnetic phenomena, due to their compactness, lead to ill posed inverse problems. Inversion procedures pursue the solution regularity through the adoption of various regularization techniques. Improper use of regularizations may unduly constrain the approximated solution and, consequently, cause significant lack of accuracy. Mathematical tools for an effective choice of the regularization technique are not available for every application, and a number of issues are still open. The paper presents a common mathematical model for most of the regularization techniques, discussing their benefits and limitations.

Findings

The paper discusses limits, applicability conditions, and impact on the performance of reconstruction procedures, of some relevant characteristics of the inversion algorithms, with particular reference to robustness against noise and inaccuracies in the system parameters.

Originality/value

Some criteria for an effective application of regularization are also discussed, showing in particular how proper choices, founded on a careful analysis of the direct problem, may reveal quite effective in improving the solution quality.
CoreLab: a component‐based integrated sizing environment
Authors: Fischer Vincent , Gerbaud Laurent
Published: July 2005

Purpose

This paper presents CoreLab, a sizing environment for electrical devices, based on a new software component standard, ICAR, which offers the possibility of multifaceted components. CoreLab supports the different steps of the sizing procedure of an electrical device by using an optimisation algorithm. It is open, which means that modules can be added to perform new functionalities.

Design/methodology/approach

The design of an electrical device has to comply with more and more constraints. In order to integrate and to manage all of these constraints during a design step, the paper proposes a sizing methodology based on an constrained optimisation by using analytical models of the device, and by encapsulating them into software components. Added to these services for the calculation of the sizing model, other services can be useful for the designer during the optimization phase, e.g. the geometry display of the device for each optimisation iteration. In this way, the approach proposes a new software component standard, Interfaces for Component Architecture (ICAR). It offers the possibility of multi‐facetted components. The paper also proposes an integrated environment to manage these software components, and their interactions: Core‐Lab. These components are then plugged to an optimisation component (algorithm), which manages the different constraints specified by the designer and finds the optimal sizing of the device.

Findings

The paper presents the ICAR standard and an environment to manage ICAR components: Core‐Lab: the creation of the components (from an analytical model or an existing computation); the projection from one component standard to another; and the composition of components to create a more complex one.

Originality/value

The use of software component approach is useful for the sizing of devices. The paper proposes a new standard to support the different aspects of the use of software components during the design of a device: ICAR. Complementary, an open integrated environment is proposed to use these components: CoreLab, but any environment being modified to accept ICAR standard can use ICAR component. So, components can be used in several environments, for example for calculation or optimisation. Components of different types can be gathered together to built a complete application for sizing, e.g. by connection of calculation components (for the sizing model), optimisation component and post‐processing components.