bluuebunny/crossref_metadata_2025 huggingface dataset:
Pore size distributions in nanoporous methyl silsesquioxane films as determined by small angle x-ray scattering
Authors: Huang E. , Toney M. F. , Volksen W. , Mecerreyes D. , Brock P. , Kim H.-C. , Hawker C. J. , Hedrick J. L. , Lee V. Y. , Magbitang T. , Miller R. D. , Lurio L. B.
Published: September 2002

Small angle x-ray scattering (SAXS) measurements were performed on nanoporous methyl silsesquioxane films that were generated by the incorporation of a sacrificial polymeric component into the matrix and subsequently removed by thermolysis. The average pore radii ranged from 1 to 5 nm over a porosity range of ∼5–50%. The distribution in pore size was relatively broad and increases in breadth with porosity. The values and observations obtained by SAXS are in good agreement with field emission scanning electron microscopy.
Onset of vortex shedding in an inline and staggered array of rectangular cylinders
Authors: Balachandar S. , Parker S. J.
Published: September 2002

The onset of vortex shedding in a periodic array of rectangular cylinders in both inline and staggered arrangement is considered and results are compared with the corresponding transition in an isolated cylinder. Numerical simulations over varying geometric arrangement of the array of cylinders over a range of Reynolds numbers is considered to establish the stability characteristics and the influence of parameters such as streamwise and transverse pitch of the periodic array. The critical Reynolds number, based on mean flow velocity and cylinder height, for the periodic array decreases significantly below its value for an isolated cylinder in cross flow. An important characteristic of flow over an inline array of cylinders is that for moderate transverse spacing the streamwise velocity profile in the wake becomes nearly sinusoidal, in which case as the transverse spacing increases the critical Reynolds number for the onset of vortex shedding decreases progressively. With further increase in transverse spacing, departure from the near-sinusoidal wake profile will increase and correspondingly the critical Reynolds number can be expected to increase after reaching a minimum to that of an isolated cylinder. A one-dimensional (1D) linear stability analysis of a sinusoidal profile is performed to explain the observed behavior. Neutral curves for the onset of convective and absolute instabilities in the wake are obtained. Based on the 1D stability analysis a unified description for the onset of vortex shedding for the varying periodic array of cylinders is obtained.
Multiple-wavelength operation of electroabsorption intensity modulator array fabricated using the one-step quantum well intermixing process
Authors: Ng S. L. , Lim H. S. , Lam Y. L. , Chan Y. C. , Ooi B. S. , Aimez V. , Beauvais J. , Beerens J.
Published: September 2002

Multiple-wavelength selective channel electroabsorption intensity modulators have been fabricated on a single InGaAs/InGaAsP chip using a one-step quantum well intermixing process. This technique was demonstrated for tailoring the intensity modulator operating wavelength by incorporating low-energy (360 keV) phosphorus ions implantation induced disordering process with gray-mask lithography technology. A modulation depth of −15 dB has been measured from these devices with a voltage swing of −4.5 V.
Charge transfer control by gate voltage in crossed nanotube junction
Authors: Yoneya Nobuhide , Tsukagoshi Kazuhito , Aoyagi Yoshinobu
Published: September 2002

We report the control of charge transfer between two crossed multiwalled carbon nanotubes (MWNTs) in a flash-memory-device configuration. An upper MWNT was used as the current channel and a second MWNT was used as the floating node underneath the channel MWNT. In this device, the source-drain current showed a clear hysteresis loop in a cyclic scan of gate voltage below 40 K. This hysteresis loop was caused by charging and discharging in the floating MWNT, and the resistance of the channel MWNT was switched between high and low. This hysteresis loop indicates that the controllable charges transferred between the two crossed MWNTs are detectable during a resistance change due to the Coulomb potential.
Dependence of physical properties and giant magnetoresistance ratio on substrate position during rf sputtering of NiO and α-Fe2O3 for bottom spin valves
Authors: Bae Seongtae , Judy Jack H. , Chen P. J. , Egelhoff W. F.
Published: September 2002

The dependence of composition, crystalline orientation texture, surface roughness, and giant magnetoresistance (GMR) ratio on substrate position during rf reactive sputtering of antiferromagnetic NiO and α-Fe2O3 films for dc magnetron sputtered Co/Cu/Co bottom spin valves have been investigated. For substrate positions from the center to edge of the target, the GMR ratio increased from 13.5% to 19.8% for NiO and from 9.8% to 13% for α-Fe2O3. These significant enhancements of GMR ratio was found to correlate with a decrease of surface roughness, increase in crystalline texture, and a nearly bulk stoichiometry of the NiO and α-Fe2O3 thin films.
Tunable laser spectroscopy of spin injection in ZnMnSe/ZnCdSe quantum structures
Authors: Buyanova I. A. , Ivanov I. G. , Monemar B. , Chen W. M. , Toropov A. A. , Terent’ev Ya. V. , Sorokin S. V. , Lebedev A. V. , Ivanov S. V. , Kop’ev P. S.
Published: September 2002

Magneto-optical spectroscopy in combination with tunable laser excitation is employed to study exciton spin alignment and injection in ZnMnSe/ZnCdSe quantum structures. This approach enables us to selectively create preferred spin orientation and to separately monitor subsequent spin injection from individual spin states, thus shedding light on a possible source of spin loss. It is shown that the limited spin polarization in a nonmagnetic quantum well due to spin injection from a ZnMnSe-based diluted magnetic semiconductor (DMS) is not caused by a limited degree of spin alignment in the DMS, which is in fact complete, but rather occurs during subsequent processes.
Detection of coherent and incoherent spin dynamics during the magnetic switching process using vector-resolved nonlinear magneto-optics
Authors: Silva T. J. , Kabos P. , Pufall M. R.
Published: September 2002

It is usually assumed that magnetic switching proceeds via coherent rotation under conditions of high symmetry. There is no a priori reason to expect an inhomogeneous response when a uniform magnetic torque is applied to a homogeneous ferromagnet. We test this assumption using vector- and time-resolved nonlinear magneto-optic measurements on a continuous Ni–Fe film. While coherent dynamics are observed when the magnetization M is initially oriented along the easy axis (the preferred axis of M in the absence of external fields), we find evidence for inhomogeneous spin dynamics when M is initially oriented perpendicular to the easy axis, which suggests the generation of incoherent spin waves during the magnetic reorientation process. The inhomogeneity is sufficient to reduce the spatially averaged magnetic moment within the measured area by almost 50%.
Direct observation of magnetization switching in focused-ion-beam-fabricated magnetic nanotubes
Authors: Khizroev Sakhrat , Kryder Mark H. , Litvinov Dmitri , Thompson David A.
Published: September 2002

In this letter, a direct measurement of “easy” magnetization switching indicating zero-magnetization remanence in a magnetic probe with a cross section as narrow as 60×60 nm2, and as tall as 750 nm, is presented. Magnetic force microscopy was utilized to test focused-ion-beam-fabricated nanomagnetic probes. The data directly indicate that unlike a regular solid probe, a probe with a tubelike ending (nanotube) provides substantially “easier” switching.
Gain-maximized GaAs/AlGaAs quantum-cascade laser with digitally graded active region
Authors: Indjin D. , Tomić S. , Ikonić Z. , Harrison P. , Kelsall R. W. , Milanović V. , Kočinac S.
Published: September 2002

An advanced strategy for the optimal design and realization of a GaAs/AlGaAs quantum-cascade laser is presented. It relies on recently established inverse scattering techniques to design an optimal smooth active region profile, followed by a conversion to an almost equivalent digitally graded structure, comprising just two different alloy compositions. In order to compare the output characteristics of optimized and previously realized structures, the intersubband electron scattering transport in quantum cascade lasers is analyzed. A full self-consistent rate equation model which includes all relevant electron-longitudinal optical phonon and electron–electron scattering mechanisms between injector/collector, active region, and continuumlike states is employed. Whilst the gain coefficients and threshold currents calculated at 77 and 300 K for the structure with a standard triple quantum well active region show excellent agreement with recent experiments, a significant improvement of these parameters is predicted for the optimized digitally graded quantum-cascade laser.
Monte Carlo simulation on the indirect exchange interactions of Co-doped ZnO film
Authors: Jalbout Abraham F. , Chen Hanning , Whittenburg Scott L.
Published: September 2002

Monte Carlo simulations using a three-dimensional lattice model studied the Ruderman–Kittel–Kasuya–Yosida (RKKY) indirect exchange interaction of doped magnetic Co ions in ZnO films. The results of the calculations show that the RKKY interaction in Co-doped ZnO is long ranged and its magnitude is proportional to R−1 (inverse of the distance R from a central Co2+ ion). The sign oscillates with a frequency that depends on the concentration of the carrier. The long-distance sum of the RKKY indirect exchange energies is positive indicating that these materials are ferromagnetic, in direct correlation with previously reported results.
X-ray diffraction and nanoindentation studies of nanocrystalline graphite at high pressures
Authors: Patterson J. Reed , Kudryavtsev Anatoliy , Vohra Yogesh K.
Published: September 2002

We report energy dispersive x-ray diffraction studies on nanocrystalline hexagonal graphite samples (average grain size=12 nm) in a diamond-anvil cell to 65 GPa at room temperature. A structural phase transition to a hexagonal diamond phase beginning at 15 GPa is completed at 55 GPa, and is reversible on decompression. The x-ray diffraction studies were followed by nanoindentation hardness measurements on the pressure treated samples. The obtained hardness values are in the range of 1–2 GPa. Unlike fullerenes, the room-temperature compression of nanocrystalline graphite to 65 GPa did not produce a superhard carbon material.
Determination of recombination parameters of phosphors from cathodoluminescent characteristics
Authors: Bukesov Sergey A. , Jeon Duk Y.
Published: September 2002

A simple method to determine recombination parameters of polycrystalline phosphor materials is proposed based on a comparison of a theoretical prediction of cathodoluminescent intensity with experimental characteristics. The obtained parameters are very sensitive to additional treatments of phosphor surface, especially to chemical modification by even small amounts of inorganic oxides. The proposed method offers a simple and rapid way of controlling recombination parameters of luminescent materials.
Intrinsic nonlinearity of the light–current characteristic of semiconductor lasers with a quantum-confined active region
Authors: Asryan Levon V. , Luryi Serge , Suris Robert A.
Published: September 2002

We describe a mechanism of nonlinearity of the light–current characteristic common to heterostructure lasers with a reduced-dimensionality active region. It arises from (i) noninstantaneous carrier capture into the active region and (ii) nonlinear (in the carrier density) recombination rate outside the active region. Because of (i), the carrier density outside the active region rises with injection current above threshold, and because of (ii), the useful fraction of current (that ends up as output light) decreases. We derive a universal closed-form expression for the internal differential quantum efficiency that holds true for quantum well, quantum wire, and quantum dot lasers.
Negative group velocity pulse tunneling through a coaxial photonic crystal
Authors: Munday J. N. , Robertson W. M.
Published: September 2002

An easily configurable experimental system is described in which negative group velocity tunneling of electrical pulses can be studied. Negative group velocity corresponds to the case in which the peak of a tunneled pulse exits before the peak of the incident pulse has entered the sample. In the experiments outlined herein, the tunneling occurs through the forbidden transmission region of a quarter-wavelength interference filter created from alternating segments of two different impedance coaxial cables. The equipment used for these experiments consists of two function generators and an oscilloscope, items typically found in most science departments.
Reduced temperature and bias-voltage dependence of the magnetoresistance in magnetic tunnel junctions with Hf-inserted Al2O3 barrier
Authors: Park Byong Guk , Lee Taek Dong
Published: September 2002

A modified tunnel barrier structure for the magnetic tunnel junction (MTJ) was fabricated by inserting a Hf layer in the middle of the Al2O3 tunnel barrier. MTJs with the Hf-inserted barrier show a higher tunnel mangnetoresistance (TMR) ratio and weaker temperature and bias-voltage dependence of TMR compared to the MTJs with a conventional Al2O3 barrier. The enhancement of the TMR ratio and the reduction of the temperature and bias-voltage dependence were attributed to the reduction of defects in the barrier.
Comparison of ultraviolet light-emitting diodes with peak emission at 340 nm grown on GaN substrate and sapphire
Authors: Yasan A. , McClintock R. , Mayes K. , Darvish S. R. , Zhang H. , Kung P. , Razeghi M. , Lee S. K. , Han J. Y.
Published: September 2002

Based on AlInGaN/AlInGaN multiquantum wells, we compare properties of ultraviolet light-emitting diodes (LED) with peak emission at 340 nm grown on free-standing hydride vapor phase epitaxially grown GaN substrate and on sapphire. For the LED grown on GaN substrate, a differential resistance as low as 13 Ω and an output power of more than one order of magnitude higher than that of the same structure grown on sapphire are achieved. Due to higher thermal conductivity of GaN, output power of the LEDs saturates at higher injection currents compared to the devices grown on sapphire.
Electron transport through quantum-dot states of n-type carbon nanotubes
Authors: Kim Yong-Hyun , Chang K. J.
Published: September 2002

We calculate electron transmission in carbon nanotube field-effect-transistors, based on a tight-binding model. For positive gate voltages, a quantum dot is formed in the nanotube between two regions doped p type by metal contacts, and the resulting quantum dot states give rise to n-type conduction. While p-type currents for negative gate voltages exhibit robustness, n currents sensitively depend on the depletion layer between regions doped p type by the contacts and n type by the gate. This feature explains the polarity of electron transport observed in carbon nanotube transistors.
Morphological instabilities of the InAs/GaAs(001) interface and their effect on the self-assembling of InAs quantum-dot arrays
Authors: Patella F. , Arciprete F. , Placidi E. , Nufris S. , Fanfoni M. , Sgarlata A. , Schiumarini D. , Balzarotti A.
Published: September 2002

The morphology of the InAs/GaAs(001) system has been imaged by atomic force microscopy (AFM) at different stages of the epitaxial growth from the initial formation of a pseudomorphic two-dimensional (2D) interace up to the self-aggregation of InAs quantum dots (QDs). The substrate texture and the dependence of the cation diffusion on the elastic strain field fully control the lateral ordering of the nanoparticles in the self assembling process and determine the final morphology of multistacked InAs QD arrays.
Multiwatt average power continua generation in holey fibers pumped by kilowatt peak power seeded ytterbium fiber amplifier
Authors: Champert P. A. , Popov S. V. , Solodyankin M. A. , Taylor J. R.
Published: September 2002

We demonstrate up to 3.8 W average power broad continuum generation in holey fibers pumped by a kilowatt peak, 10 W average power, single-mode, seeded ytterbium fiber amplifier at 1064 nm. Components of generated continua and spectral slicing indicate major contributions of Raman and Kerr nonlinearities. The proposed configuration opens the way to fully fiber integrated multiwatt white light sources.
Free-space detection of terahertz radiation using crystalline and polycrystalline ZnSe electro-optic sensors
Authors: Holzman J. F. , Vermeulen F. E. , Irvine S. E. , Elezzabi A. Y.
Published: September 2002

We present an experimental investigation demonstrating the use of single-crystal and polycrystalline ZnSe for the detection of freely propagating terahertz (THz) radiation. It is found that polycrystalline ZnSe electro-optic sensors exhibit preferred crystallographic orientations and can provide high bandwidth detection capabilities. The polycrystalline grain size and orientation are shown to be important in detecting distortion-free THz wave forms. By proper choice of the polycrystalline sensor thickness, a THz detection bandwidth comparable to that obtained with a single-crystal sensor is demonstrated. The application of polycrystalline material for free-space electro-optic sampling (FS–EOS) permits the possibility of utilizing nonlattice-matched thin-film integrated THz FS–EOS sensors and generators.
High structural order in thin films of the organic semiconductor diindenoperylene
Authors: Dürr A. C. , Schreiber F. , Münch M. , Karl N. , Krause B. , Kruppa V. , Dosch H.
Published: September 2002

We report extraordinary structural order along the surface normal in thin films of the organic semiconductor diindenoperylene (DIP) deposited on silicon–dioxide surfaces. Cross-sectional transmission electron microscopy (TEM), noncontact atomic force microscopy (NC–AFM), as well as specular and diffuse x-ray scattering measurements were performed to characterize thin films of DIP. Individual monolayers of essentially upright-standing DIP molecules could be observed in the TEM images indicative of high structural order. NC–AFM images showed large terraces with monomolecular steps of ≈16.5 Å height. Specular DIP Bragg reflections up to high order with Laue oscillations confirmed the high structural order. A semi-kinematic fit to the data allowed a precise determination of the oscillatory DIP electron density ρel.,DIP(z). The mosaicity of the DIP thin films was obtained to be smaller than 0.01°.
Kinetics of boron reactivation in doped silicon from Hall effect and spreading resistance techniques
Authors: Lilak Aaron D. , Law Mark E. , Radic Ljubo , Jones Kevin S. , Clark Mark
Published: September 2002

In this work, a series of 13 boron implants were performed into Czochralski silicon substrates with doses of 2×1014–1.6×1015 cm−2 at energies of 10–80 keV. The boron was deliberately clustered with a 750 °C anneal of 10 or 30 min and the electrical activation of the boron implants was determined following a second anneal at 750 or 850 °C with a Hall effect system with certain samples also being analyzed with a spreading resistance technique. Analysis of the reactivation rates allows for the determination of the net energy to boron reactivation to be approximately 3.0 eV assuming the reactivation process is mediated by release of a boron interstitial with a migrational energy of 0.3 eV. This results in a critical binding energy of approximately 2.7 eV from the process limiting the dissolution of the most stable boron-interstitial cluster.
Electrostatic stabilization of fluid microstructures
Authors: Mugele Frieder , Herminghaus Stephan
Published: September 2002

A liquid surface of arbitrary shape is, in general, dynamically unstable due to gradients in Laplace pressure. This greatly limits the class of morphologies eligible for artificial fluid microstructures. In this work, we demonstrate that a wide class of these otherwise unstable surface morphologies can be stabilized using electrostatic fields. Complex stable fluid microstructures were generated in a conventional electrowetting setup operated at high voltage. We present an electrostatic model that explains the stability and the scale of the stable structures as a function of external control parameters. The stability as well as the universality of these structures naturally leads to novel concepts in microfluidic technology.
Demonstration of reverse symmetry waveguide sensing in aqueous solutions
Authors: Horváth Róbert , Pedersen Henrik C. , Larsen Niels B.
Published: September 2002

A reverse symmetry waveguide is presented for evanescent wave sensing in aqueous solutions. The waveguide consists of a thin polystyrene film, supported by a thicker substrate layer of nanoporous silica on glass. The nanoporous substrate layer has a refractive index of nS=1.193, hence, with an aqueous cover refractive index of nC=1.331, a reverse symmetry (nS<nC) is obtained. A surface relief grating formed in the polystyrene film is used as a coupling element. Sensitivities considerably higher than for a conventional waveguide sensor are demonstrated.
Molecular rectification at 8 K in an Au/C16H33Q-3CNQ LB film/ Au structure
Authors: Okazaki Nobuharu , Sambles J. Roy , Jory Michael J. , Ashwell Geoffrey J.
Published: September 2002

The nonlinear I/V characteristics of a molecular rectifier structure of the form Au/20 layers of C16H33Q-3CNQ/Au have been explored from 8 to 300 K. At 8 K the voltage-controlled nonlinear conduction is explored in the absence of thermal effects. At the highest voltages (±15 V) at 8 K the rectification ratio was about 4 with current densities as high as 1000 A m−2 and log I varying as |V|0.5, indicating voltage-controlled hopping. The likely explanation for the complete I/V characteristics rests with the insulating aliphatic tails, which provide substantial electrical barriers within the structure.
Light-induced assembly of tailored droplet arrays in nematic emulsions
Authors: Yamamoto Takahiro , Yamamoto Jun , Lev Bohdan I. , Yokoyama Hiroshi
Published: September 2002

Dynamic manipulation of droplets could be achieved by light in a nematic liquid crystal (LC) doped with photochromic azobenzene derivatives. On irradiation of ultraviolet light, the trans→cis photoisomerization drives a directional motion of the droplets towards the cis-rich region and assembled close-packed two-dimensional hexagonal colloidal crystals. This behavior is mainly attributable to the reduction of the droplet-LC interfacial tension, associated with the enhanced surface activity of cis isomers. We also performed photochemical assembly of tailored droplet arrays by projection of computer-generated images on the samples. The photoinduced manipulation of droplets will provide a versatile approach to microstructuring of LC devices.
On the evolution of maximum turbulent kinetic energy production in a channel flow
Authors: Laadhari F.
Published: September 2002

The Reynolds number effects on turbulent kinetic energy production and mean transport terms in near-wall turbulent channel flow are investigated analytically and with the help of direct numerical simulations (DNS). Using the momentum equation for turbulent channel flow, an analytical expression for the envelope of turbulent kinetic energy production curves is derived. It is shown that this envelope coincides with the wall-normal position at which the turbulent and viscous shear stress are equal. The DNS results carried out corroborate this finding and assess other quantitative details, namely the evolution of the peak of kinetic energy production and of its wall-normal position in terms of the Reynolds number. Empirical relations for the envelopes of the mean momentum transport terms and for their extrema position are also derived.
The skeletal muscle Ca
2+
release channel has an oxidoreductase-like domain
Authors: Baker Matthew L. , Serysheva Irina I. , Sencer Serap , Wu Yili , Ludtke Steven J. , Jiang Wen , Hamilton Susan L. , Chiu Wah
Published: September 2002

We used a combination of bioinformatics, electron cryomicroscopy, and biochemical techniques to identify an oxidoreductase-like domain in the skeletal muscle Ca
2+
release channel protein (RyR1). The initial prediction was derived from sequence-based fold recognition for the N-terminal region (41–420) of RyR1. The putative domain was computationally localized to the clamp domain in the cytoplasmic region of a 22Å structure of RyR1. This localization was subsequently confirmed by difference imaging with a sequence specific antibody. Consistent with the prediction of an oxidoreductase domain, RyR1 binds [
3
H]NAD
+
, supporting a model in which RyR1 has a oxidoreductase-like domain that could function as a type of redox sensor.
Ubiquitination of inducible nitric oxide synthase is required for its degradation
Authors: Kolodziejski Pawel J. , Musial Aleksandra , Koo Ja-Seok , Eissa N. Tony
Published: September 2002

Inducible nitric oxide synthase (iNOS) is responsible for nitric oxide (NO) synthesis from
l
-arginine in response to inflammatory mediators. We have previously shown that iNOS is degraded through the 26S proteasome. Targeting of proteins for proteasomal degradation may or may not require their covalent linkage to multiubiquitin chains (ubiquitination). In addition, ubiquitination of a protein can serve functions other than signaling proteolysis. In this context, it is not known whether iNOS is subject to ubiquitination or whether ubiquitination is required for its degradation. In this study, we show that iNOS, expressed in HEK293 cells or induced in primary bronchial epithelial cells, A549 cells, or murine macrophages, is subject to ubiquitination. To investigate whether iNOS ubiquitination is required for its degradation, HEK293T cells were cotransfected with plasmids containing cDNAs of human iNOS and of the dominant negative ubiquitin mutant K48R. Disruption of ubiquitination by K48R ubiquitin resulted in inhibition of iNOS degradation. ts20 is a mutant cell line that contains a thermolabile ubiquitin-activating enzyme (E1) that is inactivated at elevated temperature, preventing ubiquitination. Incubation of ts20 cells, stably expressing human iNOS, at the nonpermissive temperature (40°C) resulted in inhibition of iNOS degradation and marked accumulation of iNOS. These studies indicate that iNOS is subject to ubiquitination and that ubiquitination is required for its degradation.
Elites and popular nationalism*
Authors: Whitmeyer Joseph M.
Published: September 2002

Much current theory concerning nationalism holds that elites commonly create or cause popular nationalism. In part, that thesis may be due to an overwhelming emphasis in research on nationalism on positive cases: cases where nationalism has appeared, ignoring cases where it has not. In this article, I challenge the thesis by showing numerous historical cases in which elites have promoted nationalisms that ordinary people have not adopted, or in which ordinary people have adopted a nationalism before it was taken up by elites. Even if elites do not create popular nationalism, however, they can and do shape itsexpressionin a variety of ways, such as organizing it, providing relevant information, or providing opportunity or incentive for it. I show this through historical examples.
Interpersonal trust and voluntary associations: examining three approaches
Authors: Anheier Helmut , Kendall Jeremy
Published: September 2002

The relationship between interpersonal trust and membership in voluntary associations is a persistent research finding in sociology. What is more, the notion of trust has become a central issue in current social science theorizing covering such diverse approaches as transaction costs economics or cognitive sociology. In different ways and for different purposes, these approaches address the role of voluntary organizations, although, as this paper argues, much of this thinking remains sketchy and underdeveloped. Against an empirical portrait of this relationship, the purpose of this paper is to assess such theorizing. We first set out to explicate major approaches to trust in economics, sociology and political science, using the non‐profit or voluntary organization as a focal point. We then examine the various approaches in terms of their strengths and weaknesses, and, finally, identify key areas for theoretical development. In particular, we point to the social movement literature, the social psychology of trust, and recent thinking about civil society.
Graduate density, gender, and employment
Authors: Brynin Malcolm
Published: September 2002

The expansion of higher education is often viewed as reflecting increased demand for skills, whether related to technological change or the growing complexity of the economy. It is also linked to widening pay differentials between the poorly and highly educated. There are reasons, however, to question these associations. Even if demand for graduates is growing the supply of graduates might as a result of the status derived from having a degree still exceed this. The demand for graduates itself need not be wholly tied in with upgrading of the labour force. Graduates could be part of a more flexible workforce who increasingly undertake non‐graduate work, thus downgrading their labour‐market position. LFS (Labour Force Survey) and BHPS (British Household Panel Study) data are used to show that there has been no major shift in the distribution of graduates in the British labour market, that career starts are increasingly at a lower status point, and that there is a negative effect of graduate density on wages. There are also redistributional effects. There has been a large increase in the social demand for higher education by women, and they have gained from this expansion while men have lost out. In addition, graduate density is positive for non‐graduates, who gain from the reduced rewards accruing to graduates. The results call into question the simple idea of a trend towards a demand for increasing levels of skills and qualifications. More attention should be paid to the distribution of skills and to complex interactions within this.
Weberian perspectives on science, technology and the economy
Authors: Schroeder Ralph , Swedberg Richard
Published: September 2002

Several disciplines have contributed to the understanding of the relationship between science, technology, and economic change. Weber's perspective on this relationship, however, has not been properly explored. In the first part of this paper, we give an account of Weber's perspective. In the second part, we critically assess Weber's ideas, indicating those that are useful and those that deserve to be abandoned. We also confront a revised Weberian perspective with those of the main contemporary competitors, the key ideas of economists and economic historians on one side and social constructivists on the other. We conclude that a Weberian comparative‐historical approach compares favourably with these competitors, and suggest where his approach still requires further work.
Regulating ‘unruly’ bodies: work tasks, conflict and violence in Britain's night‐time economy1
Authors: Monaghan Lee F.
Published: September 2002

Security work in urban licensed premises is a risky occupation in Britain's fast expanding liminal night‐time economy. Sociologically, little is known about this masculinist work, including those embodied strategies used by doorstaff or ‘bouncers’ to regulate ‘unruly’ bodies in and around commercial space. Using participant observational data generated in south‐west Britain, this paper describes how the door supervisors’ routine work tasks (largely comprising requests and demands) provide the conditions of possibility for hierarchical conflict and (near) violence between themselves and (potential) customers inside and at the entrances to licensed premises. Besides providing a thick description of this work and the phenomenology of physical violence, the paper supports recent theoretical arguments for an explicitly embodied sociology. Centrally, the paper maintains that bodies matter and that an empirical, inter‐pretative sociology cannot ignore the corporeal dimensions of social life if it is to arrive at an adequate understanding of everynight tensions and conflict.
The theorization of social co‐ordinations in differentiated societies: the theory of generalized symbolic media in Parsons, Luhmann and Habermas*
Authors: Chernilo Daniel
Published: September 2002

The problem of the differentiation of societies is at the core of the sociological imagination about the rise of modernity. In postwar sociology, T. Parsons developed the theory of generalized symbolic media in the mid‐1960s to tackle, theoretically and historically, the issue of differentiation. According to him, the interchange media are defined as resources oriented to exchange processes between the subsystems of the social system. Starting with money, Parsons argues that the remaining media (power, influence, and value‐commitments) have a set of characteristics defined as common properties for all media. After this first formulation, contemporary theorists such as Niklas Luhmann and Jürgen Habermas have developed and modified the Parsonian theory: Luhmann rejects the idea of interchange and proposes the use of communication; Habermas distinguishes between steering and communication media. In all three cases, the focus of the theory is on the characterization of the strongest dynamics of social co‐ordination present in differentiated societies. A major result of these developments is the inclusion of new dimensions on which to conceive the properties of media, not only those of money but also language. Beyond differences, then, it is proposed that there is only one theory of generalized symbolic media which can be understood as a progressive research programme, in Lakatos’ terms. Finally, the hand‐in‐hand evolution between the theory of media and Habermas’ and Luhmann's re‐conceptualizations on societal differentiation in contemporary societies will also be revealed.
Researching youth culture and popular music: a methodological critique
Authors: Bennett Andy
Published: September 2002

In this article I argue the need for critical evaluation of qualitative research methodology in sociological studies of the relationship between youth culture and popular music. As the article illustrates, there is currently an absence of critical debate concerning methodological issues in this field of sociological research. In the first part of the article I begin to account for this absence by illustrating how early research on youth and music rejected the need for empirical research, relying instead on theories and concepts drawn from cultural Marxism. The second part of the article illustrates how the legacy of this early body of work in youth and music research manifests itself in current research which, although empirically grounded, is characterized by an almost total lack of engagement with methodological issues such as negotiating access to the field, manangment of field relations and ethical codes. Similarly problematic is the uncritical acceptance on the part of some researchers of their insider knowledge of particular youth musics and scenes as a means of gathering empirical data. In the final part of the article I focus on the issue of insider knowledge and the need for critical evaluation of its use as a methodological tool in field‐based youth and music research.
Hope and despair: making sense of politics in the twenty‐first century
Authors: Stewart Angus
Published: September 2002

Books reviewed in this article:

Books Reviewed:

J. Dunn 2000 The Cunning of Unreason: Making Sense of Politics

R. D. Putnam 2000 Bowling Alone: The Collapse and Revival of American Community

B. Parekh 2000 Rethinking Multiculturalism: Cultural Diversity and Political Theory

J. Drysek 2000 Deliberative Democracy and Beyond
Power and agency
Authors: Lukes Steven
Published: September 2002

Book Reviewed:

Clarissa Hayward 2000 De‐Facing Power
Xenobiotic Transporters: Another Protective Mechanism for Chemicals
Authors: Klaassen Curtis D.
Published: September 2002

Xenobiotic transporters are responsible for the uptake of some chemicals into cells, and extremely important for the export of chemicals out of cells. A number of families of xenobiotic transporters have been cloned the last few years. Some microsomal enzyme inducers will enhance the plasma disappearance and biliary excretion of some xenobiotics that are not biotransformed in the intact animal, as well as in isolated hepatocytes. This is due to an up-regulation of xenobiotic transporters. As a result, some microsomal enzyme inducers will enhance the elimination and decrease the toxicity of some chemicals by enhanced transport.
A 13-Week Feeding Study in the Rat with Shea Oleine and Hardened Shea Oleine
Authors: Earl Lesley K. , Baldrick Paul , Hepburn Paul A.
Published: September 2002

Shea oleine is an oil fraction derived from the nut of the tree, Butyrospermum parkii, which grows in central and western Africa. There are several uses of shea oleine, including its use as a cooking oil and, after hardening, in margarine and toffee fat. As part of a series of studies, a 13-week rat feeding study was conducted in which groups of Colworth-Wistar rats (15 male and 15 female) were fed 27.5% total fat semipurified diets containing 20% (w/w) shea oleine (SU) or hardened shea oleine (SH). Equivalent groups of rats were fed either 20% ( w/w) palm oil (PU), soyabean oil (BU), or the hardened (hydrogenated) equivalents (PH and BH, respectively). Assessments of body weight, food and water intake, clinical pathology, organ weights, and macroscopic histopathology were carried out. Results showed that shea oleine diets produced similar biological effects to palm oil and and soyabean oil diets. A slightly reduced body weight gain was noted in rats fed either of the shea oleine diets in comparison with palm oil and soyabean oil. The process of hardening had no significant impact on the normal growth in rats fed shea oleine, although minor differences compared with un-hardened diets comprised some small changes in clinical chemistry parameters, raised fiver weight, and less liver lipid. In addition, raised alkaline phosphatase and an increase in food intake were noted in rats fed SH. All diets were well tolerated in the growing rat and none of the findings in the study were considered to be adverse.
Inhalation Toxicology of Octamethylcyclotetrasiloxane (D4) Following a 3-Month Nose-Only Exposure in Fischer 344 Rats
Authors: Burns-Naas Leigh Ann , Meeks Robert G. , Kolesar Gary B. , Mast Richard W. , Elwell Michael R. , Hardisty Jerry F. , Thevenaz Philippe
Published: September 2002

Octamethylcyclotetrasiloxane (D4) is a low-molecular-weight cyclic siloxane used primarily in the synthesis of silicone polymers. The objective of the present study was to evaluate the subchronic toxicity of D4 following a 3-month nose-only inhalation exposure. Male and female Fischer 344 rats (20/sex/group) were exposed 6 h/day, 5 days/week for 3 months to vapor concentrations of 0, 35, 122, 488, and 898 ppm D4. Also, an additional 10 per sex in the control and high-exposure groups were allowed a 4-week recovery period to observe reversibility, persistence, or delayed occurrence of any potential adverse effects. Body weights and food consumption were monitored at least twice weekly over the course of exposures. Approximately 18 hours preceding euthanasia, animals were transferred into metabolism cages for urine collection, and were fasted. At necropsy, rats were anesthetized with pentobarbital and euthanized by exsanguination. Blood was collected for hematological and clinical biochemical analyses. Selected organ weights were measured and a complete set of tissues was taken for histopathological examination. A concentration-dependent increase in absolute and relative liver weight (488 to 898 ppm) and a significant decrease in ovarian weight (898 ppm) were observed in female rats. Exposure to D4 via nose-only inhalation (35 to 898 ppm) produced minor alterations in hematological and serum chemistry parameters that were considered either incidental and of little toxicological significance (hematology) or suggestive of metabolic adaptation/alteration (serum chemistry) in response to exposure-related hepatomegaly. There were no histopathological findings noted in the liver. Histopathological evidence indicated the primary target organs following D4 inhalation exposure to be components of the female reproductive tract. Reversible histopathological changes were observed in the ovary (hypoactivity) and vagina (mucification) of female rats in the high-dose group only (898 ppm). Although an increase in the incidence and severity of both macrophage accumulation, interstitial inflammation, and eosinophil infiltration was observed in the lungs of male and female rats exposed to D4, the toxicological significance is uncertain as other inhalation studies at similar concentrations failed to show these effects. In summary, nose-only inhalation of a high concentration of D4 resulted in reversible histopathological changes in the female rat reproductive tract. Lower concentrations did not elicit these same effects.
Use of Genetically Engineered Mice in Drug Discovery and Development: Wielding Occam's Razor to Prune the Product Portfolio
Authors: Bolon Brad , Galbreath Elizabeth
Published: September 2002

Genetically engineered mice (GEMs) that either overexpress (transgenic) or lack (gene-targeted, or “knock-out”) genes are used increasingly in industry to investigate molecular mechanisms of disease, to evaluate innovative therapeutic targets, and to screen agents for efficacy and/or toxicity. High throughput GEM construction in drug discovery and development (DDD) serves two main purposes: to test whether a given gene participates in a disease condition, or to determine the function(s) of a protein that is encoded by an expressed sequence tag (EST, an mRNA fragment for a previously uncharacterized protein). In some instances, pheno-types induced by such novel GEMs also may yield clues regarding potential target organs and toxic effects of potential therapeutic molecules. The battery of tests used in phenotypic analysis of GEMs varies between companies, but the goal is to define one or more easily measured endpoints that can be used to monitor the disease course—especially during in vivo treatment with novel drug candidates. In many DDD projects, overt phenotypes are subtle or absent even in GEMs in which high-level expression or total ablation of an engineered gene can be confirmed. This outcome presents a major quandary for biotechnology and pharmaceutical firms: given the significant expense and labor required to generate GEMs, what should be done with “negative” constructs? The 14th century philosophic al principle known as Occam's razor—that the simplest explanation for a phenomenon is likely the truth—provides a reasonable basis for pruning potential therapeutic molecules and targets. In the context of DDD, Occam's razor may be construed to mean that correctly engineered GEMs lacking obvious functional or structural phenotypes have none because the affected gene is not uniquely essential to normal homeostasis or disease progression. Thus, a “negative” GEM construct suggests that the gene under investigation encodes a ligand or target molecule without significant therapeutic potential. This interpretation indicates that, at least in a market-driven industrial setting, such “negative” projects should be pruned aggressively so that resources may be redirected to more promising DDD ventures.
Evaluation of the Tg.AC Transgenic Mouse Assay for Testing the Human Carcinogenic Potential of Pharmaceuticals—Practical Pointers, Mechanistic Clues, and New Questions
Authors: Sistare Frank D. , Thompson Karol L. , Honchel Ronald , DeGeorge Joseph
Published: September 2002

Transgenic mouse strains with genetic alterations known to play a role in the multistage process of carcinogenesis are being used increasingly as models for evaluating the human carcinogenic potential of chemicals and Pharmaceuticals. The Tg.AC transgenic mouse is one of the strains currently being used in such alternative short-term carcinogenicity testing protocols. This review is focused on recent data from studies designed to evaluate this model's ability to discriminate carcinogens from noncarcinogens. Details relating to protocol design that can significantly impact study outcome are described. Data relating to mechanisms of chemical tumor induction in the Tg.AC model are reviewed, and questions have been formulated to encourage research to further guide appropriate future applications of this model.
Health promotive action and preventive action model (HPA model) for the classification of health care services in public health nursing
Authors: Elo Sirkka L. , Calltorp Johan B.
Published: September 2002

Background: There is a need for an expanded approach to develop knowledge of public health nursing as a sphere of public health. The aim of this paper was to construct a theoretical model for healthcare services in the area of public health nursing based on the analysis and classification of healthcare services used in public health nursing practice. Methods: Patient records were examined using a qualitative research approach. The categorization and classification of the actions followed certain criteria. Three methods were used for verifying and modifying the concept. Results: Of the identified categories 34 dealt with healthcare services, three with administrative services, and five with coordination. The six recognized domains of the healthcare services are health promotive services, health protective services, diagnostic services, therapeutic services, rehabilitation services, and terminal healthcare services. Using the public health approach, the Health promotive action and preventive action model (HPA model) was constructed in order to visualize where in the course of the process of health-ill health and developmental stages the public health nurses provide healthcare services. Health promotion and the levels of prevention are described on the operational and conceptual levels in this paper. Conclusions: The result is expected to have an important effect on how public health nurses conceptualize their field of knowledge. The classification reflects current public health policy by focusing on health promotion and illness prevention. The developed HPA model will support health service research.
Environmental illness - effectiveness of a salutogenic group-intervention programme
Authors: Hillert Lena , Savlin Pirjo , Levy Berg Adrienne , Heidenberg Anna , Kolmodin-Hedman Birgitta
Published: September 2002

Aims: Hypersensitivity to electricity (HE) is a common form of reported environmental illness in Sweden. Functional somatic symptoms has been attributed to exposure to activated electrical equipment, but no causal relationship to electromagnetic fields has been proved. In many cases, traumatic life events and psychosocial stress can be identified, but patients often reject psychological explanations. This study evaluates the effectiveness of a new short-term group-intervention programme. Methods: A multidisciplinary team developed a short-term group-intervention programme, with a salutogenic approach that focuses on somatic and psychological reactions. Twenty-two patients (14 women and 8 men) who reported HE participated in eight weekly sessions of group meetings and physiotherapy. The effect of the programme was evaluated with regard to changes in work capacity, subjective well-being, coping ability, body awareness and physical fitness. Results: Contrary to our hypothesis physical fitness was not remarkably low. Muscular tension was reduced and body awareness increased but no significant change in symptoms was observed. Individual differences in progress were observed. Fourteen patients chose to continue with psychotherapy or physiotherapy. Conclusions: Participants accepted the programme very well. One important result was identification of underlying contributing factors and motivation for further therapy. A multidisciplinary group-intervention programme with a salutogenic approach might be a useful approach to patients with medically unexplained symptoms in primary healthcare.