bluuebunny/crossref_metadata_2025 huggingface dataset:
Novel structural determinants of single-channel conductance in nicotinic acetylcholine and 5-hydroxytryptamine type-3 receptors
Authors: Peters J.A. , Carland J.E. , Cooper M.A. , Livesey M.R. , Deeb T.Z. , Hales T.G. , Lambert J.J.
Published: October 2006

Nicotinic ACh (acetylcholine) and 5-HT3 (5-hydroxytryptamine type-3) receptors are cation-selective ion channels of the Cys-loop transmitter-gated ion channel superfamily. Numerous lines of evidence indicate that the channel lining domain of such receptors is formed by the α-helical M2 domain (second transmembrane domain) contributed by each of five subunits present within the receptor complex. Specific amino acid residues within the M2 domain have accordingly been demonstrated to influence both single-channel conductance (γ) and ion selectivity. However, it is now clear from work performed on the homomeric 5-HT3A receptor, heteromeric 5-HT3A/5-HT3B receptor and 5-HT3A/5-HT3B receptor subunit chimaeric constructs that an additional major determinant of γ resides within a cytoplasmic domain of the receptor termed the MA-stretch (membrane-associated stretch). The MA-stretch, within the M3–M4 loop, is not traditionally thought to be implicated in ion permeation and selection. Here, we describe how such observations extend to a representative neuronal nicotinic ACh receptor composed of α4 and β2 subunits and, by inference, probably other members of the Cys-loop family. In addition, we will attempt to interpret our results within the context of a recently developed atomic scale model of the nicotinic ACh receptor of Torpedo marmorata (marbled electric ray).
Role of voltage-gated L-type Ca2+ channel isoforms for brain function
Authors: Striessnig J. , Koschak A. , Sinnegger-Brauns M.J. , Hetzenauer A. , Nguyen N.K. , Busquet P. , Pelster G. , Singewald N.
Published: October 2006

Voltage-gated LTCCs (L-type Ca2+ channels) are established drug targets for the treatment of cardiovascular diseases. LTCCs are also expressed outside the cardiovascular system. In the brain, LTCCs control synaptic plasticity in neurons, and DHP (dihydropyridine) LTCC blockers such as nifedipine modulate brain function (such as fear memory extinction and depression-like behaviour). Voltage-sensitive Ca2+ channels Cav1.2 and Cav1.3 are the predominant brain LTCCs. As DHPs and other classes of organic LTCC blockers inhibit both isoforms, their pharmacological distinction is impossible and their individual contributions to defined brain functions remain largely unknown. Here, we summarize our recent experiments with two genetically modified mouse strains, which we generated to explore the individual biophysical features of Cav1.2 and Cav1.3 LTCCs and to determine their relative contributions to various physiological peripheral and neuronal functions. The results described here also allow predictions about the pharmacotherapeutic potential of isoform-selective LTCC modulators.
Role of ryanodine receptor mutations in cardiac pathology: more questions than answers?
Authors: Thomas N.L. , George C.H. , Lai F.A.
Published: October 2006

The RyR (ryanodine receptor) mediates rapid Ca2+ efflux from the ER (endoplasmic reticulum) and is responsible for triggering numerous Ca2+-activated physiological processes. The most studied RyR-mediated process is excitation–contraction coupling in striated muscle, where plasma membrane excitation is transmitted to the cell interior and results in Ca2+ efflux that triggers myocyte contraction. Recently, single-residue mutations in the cardiac RyR (RyR2) have been identified in families that exhibit CPVT (catecholaminergic polymorphic ventricular tachycardia), a condition in which physical or emotional stress can trigger severe tachyarrhythmias that can lead to sudden cardiac death. The RyR2 mutations in CPVT are clustered in the N- and C-terminal domains, as well as in a central domain. Further, a critical signalling role for dysfunctional RyR2 has also been implicated in the generation of arrhythmias in the common condition of HF (heart failure). We have prepared cardiac RyR2 plasmids with various CPVT mutations to enable expression and analysis of Ca2+ release mediated by the wild-type and mutated RyR2. These studies suggest that the mutational locus may be important in the mechanism of Ca2+ channel dysfunction. Understanding the causes of aberrant Ca2+ release via RyR2 may assist in the development of effective treatments for the ventricular arrhythmias that often leads to sudden death in HF and in CPVT.
Redox signalling involving NADPH oxidase-derived reactive oxygen species
Authors: Dworakowski R. , Anilkumar N. , Zhang M. , Shah A.M.
Published: October 2006

Increased oxidative stress plays an important role in the pathophysiology of many diseases such as atherosclerosis, diabetes mellitus, myocardial infarction and heart failure. In addition to the well-known damaging effects of oxygen-free radicals, ROS (reactive oxygen species) also have signalling roles, acting as second messengers that modulate the activity of diverse intracellular signalling pathways and transcription factors, thereby inducing changes in cell phenotype. NADPH oxidases appear to be especially important sources of ROS involved in redox signalling. Seven NADPH oxidase isoforms, known as Noxs (NAPDH oxidases), are expressed in a cell- and tissue-specific fashion. These oxidases are thought to subserve distinct functions as a result of their tightly regulated activation (e.g. by neurohormonal and growth factors and mechanical stimuli) and their specific coupling with distinct downstream signalling pathways. In the present paper, we review the structure and mechanisms of activation of NADPH oxidases and consider their involvement in redox signalling, focusing mainly on the cardiovascular system.
Confined alpha particle diagnostic system using an energetic He beam for ITER
Authors: Sasao M. , Shinto K. , Isobe M. , Nishiura M. , Kaneko O. , Wada M. , Walker C. I. , Kitajima S. , Okamoto A. , Sugawara H. , Takeuchi S. , Tanaka N. , Aoyama H. , Kisaki M.
Published: October 2006

The beam neutralization system for measurement of the spatial and velocity distributions of alpha particles of ITER plasmas was studied. As forward angle detection against the beam injection direction is required for effective neutralization, arrangement of the measurement system using possible ports in ITER configuration is proposed. The count rate of neutralized alpha particles produced by the double charge exchange interaction with energetic He0 beam particles injected is estimated. The ratios of signal to neutron-induced noise are evaluated. When a He0 beam produced by autodetachment from a 1–1.5MeV He− beam of 10mA is injected, the signal to noise ratio becomes greater than 1 at ρ<0.4, even without beam modulation. Usage of a lock-in technique at the frequency of radio-frequency quadrapole accelerator will make measurement at the outer region possible.
Dual, orthogonal, backlit pinhole radiography in OMEGA experiments
Authors: Kuranz C. C. , Blue B. E. , Drake R. P. , Robey H. F. , Hansen J. F. , Knauer J. P. , Grosskopf M. J. , Krauland C. , Marion D. C.
Published: October 2006

Backlit pinhole radiography used with ungated film as a detector creates x-ray radiographs with increased resolution and contrast. Current hydrodynamics experiments on the OMEGA Laser use a three-dimensional sinusoidal pattern as a seed perturbation for the study of instabilities. The structure of this perturbation makes it highly desirable to obtain two simultaneous orthogonal backlighting views. We accomplished this using two backlit pinholes each mounted 12mm from the target. The pinholes, of varying size and shape, were centered on 5mm square foils of 50μm thick Ta. The backlighting is by K-alpha emission from a 500μm square Ti or Sc foil mounted 500μm from the Ta on a plastic substrate. Four laser beams overfill the metal foil, so that the expanding plastic provides radial tamping of the expanding metal plasma. The resulting x-rays pass through the target onto (ungated) direct exposure film (DEF). Interference between the two views is reduced by using a nose cone in front of the DEF, typically with a 9mm Ta aperture and with magnets to deflect electrons. Comparison of varying types of pinholes and film exposures will be presented from recent experiments as well as an analysis of the background noise created using this experimental technique.
Resonance counting function in black box scattering
Authors: Donnelly Harold
Published: October 2006

Sjostrand and Zworski [J. Am. Math. Soc. 4, 729–769 (1991)] proved a universal upper bound for the resonance counting function in black box scattering. Examples are presented which show that there is no corresponding general lower bound.
Two-frequency undulator and harmonic generation by an ultrarelativistic electron
Authors: Dattoli G. , Mikhailin V. V. , Ottaviani P. L. , Zhukovsky K. V.
Published: October 2006

The spectrum of electromagnetic radiation of a relativistic electron moving in the magnetic field oscillating in two mutually transversal spatial directions with two different frequencies is analytically investigated. The spectral properties of radiation in the planar biharmonic undulator are also discussed. The technique based on the associated Bessel functions was effectively applied in our calculations. The effect of the magnetic field and the undulator parameters on the radiation of the fundamental as well as low and high harmonics was elucidated. It is demonstrated that the biharmonic undulator can be exploited to regulate the emission of certain selected harmonics and hence contribute to the development of the efficient devices with high extraction and narrow spectrum.
Yellow-to-violet, blue, and green frequency upconversions in Nd3+-doped PbWO4 single crystal
Authors: Huang Yanlin , Jang Kyoung Hyuk , Seo Hyo Jin , Jang Kiwan
Published: October 2006

Upconversion emission properties of Nd3+ ions doped in PbWO4 crystal are investigated by pulsed laser excitation into the G5∕24+G2(1)7∕2 levels at temperatures from 10to295K. The main upconversion emission consists of strong blue emission bands in the wavelength region of 435–447nm corresponding to the P1∕22→I9∕24 transitions. Some UV bands located in the wavelength region of 356–397nm corresponding to the D3∕24→I9∕24, I11∕24, and I13∕24 transitions and weak green emission at 525.2nm corresponding to the G7∕24→I9∕24 transition are observed. Several upconversion blue emissions from the P1∕22 level and the absoprtion lines due to the I9∕24→P1∕22 transition indicate multisite structure of the Nd3+ ions in the PbWO4 lattices. We investigate the excitation spectra of the upconversion emissions and their pump power dependence and lifetimes from which the probable upconversion mechanisms are proposed and analyzed. The dominant mechanisms for the upconversion emission originating from the D3∕24 level (UV emission) and the P1∕22 level (blue emission) are proven to be the sequential two-photon excited-state absorption, while the energy transfer upconversion process is responsible for the green upconversion emission from the G7∕24 level of Nd3+.
Active bimorph-based tapping-mode distance control for scanning near-field optical microscopy of biological samples in liquid
Authors: Lei F. H. , Huang L. , Piot O. , Trussardi A. , Manfait M. , Shang G. , Troyon M.
Published: October 2006

Commonly used shear force scanning near-field optical microscopy (SNOM) of soft biological samples is more critical to implement in aqueous environment than in air. A tapping-mode distance control based on a rectangular piezoelectric bimorph cantilever attached vertically by a straight fiber tip as force sensor for SNOM is introduced. The bimorph lever serving as both the probe dither and the force responder operates in flexural mode with a spring constant k=3.7×103N∕m. The sensitivity of the sensor is enhanced through the increase in lever’s quality factor (Q) and the usage of a higher eigenmode. Experimental results reveal that the describe sensor can operate in liquid with an effective Q up to 103 at its second eigenfrequecy f2=18.8kHz. High sensitivity of the sensor is demonstrated by imaging soft biological samples. Near-field optical resolution of better than 100nm on red blood cells in water is obtained. Compared to the existing tapping mode SNOM setups, our approach is compact, sensitive, lacking in parasitic optical background, and easy to practice in liquid.
Dynamical conductance of model DNA sequences
Authors: Ren Wei , Wang Jian , Ma Zhongshui , Guo Hong
Published: October 2006

Using a tight binding model, we have investigated charge transport in model DNA sequences under external ac bias. The numerical results of emittance for several model DNA sequences are found to be well described by an analytical formula, especially when the dynamic response is inductivelike. This formula can be understood from general considerations of scattering matrix theory. The temperature dependence of emittance is also studied numerically within the tight binding model, and dynamic response of the model DNA sequences can change from inductivelike to capacitivelike as temperature is varied.
Multiple stacking of self-assembled InAs quantum dots embedded by GaNAs strain compensating layers
Authors: Oshima Ryuji , Hashimoto Takayuki , Shigekawa Hidemi , Okada Yoshitaka
Published: October 2006

We have investigated a growth technique to realize high-quality multiple stacking of self-assembled InAs quantum dots (QDs) on GaAs (001) substrates, in which GaNxAs1−x dilute nitride material was used as a strain compensation layer (SCL). The growth was achieved by atomic hydrogen-assisted rf molecular beam epitaxy, and the effect of strain compensation was systematically investigated by using high-resolution x-ray diffraction measurements. By controlling the net average lattice strain to a minimum by covering each QD layer with a 40-nm-thick GaN0.005As0.995 SCL, we obtained a superior QD structure with no degradation in size homogeneity. Further, no dislocations were generated even after 30 layers of stacking, and the area density of QDs amounted to as high as 3×1012cm−2. The photoluminescence peak linewidth was improved by about 22% for QDs embedded in GaNAs SCLs as the accumulation of lattice strain with increasing growth of QD layers was avoided, which would otherwise commonly lead to degradation of size homogeneity and generation of dislocations.
Time dependent quantum dynamics study of the O++H2(v=,j=)→OH++H ion-molecule reaction and isotopic variants (D2,HD)
Authors: Martínez Rodrigo , Sierra José Daniel , Gray Stephen K. , González Miguel
Published: October 2006

The time dependent real wave packet method using the helicity decoupling approximation was used to calculate the cross section evolution with collision energy (excitation function) of the O++H2(v=0,j=0)→OH++H reaction and its isotopic variants with D2 and HD, using the best available ab initio analytical potential energy surface. The comparison of the calculated excitation functions with exact quantum results and experimental data showed that the present quantum dynamics approach is a very useful tool for the study of the selected and related systems, in a quite wide collision energy interval (approximately 0.0–1.1eV), involving a much lower computational cost than the quantum exact methods and without a significant loss of accuracy in the cross sections.
Density functional study on a light-harvesting carotenoid-porphyrin-C60 molecular triad
Authors: Baruah Tunna , Pederson Mark R.
Published: October 2006

We present a study on the electronic structure of a biology-inspired molecular triad which shows promises in replicating photosynthesis process in the laboratory. The triad contains three different units—C60, porphyrin, and β-carotenoid. We present its geometrical and electronic structure, dipole moments, optical absorption spectrum, and polarizability calculated with an all-electron density functional approach. Such a study will be useful for further understanding of its photoconversion properties.
Methods of determining the contact between a probe and a surface under scanning electron microscopy
Authors: Nien C.-H. , Tsai C. H. , Shin K. Y. , Jian W. B.
Published: October 2006

Based on the charging effect common to various kinds of electron microscopy, we have developed novel methods of determining “when” and “where” a probe starts to contact an electrically isolated surface. The touchdown of an electrically grounded probe leads to an acute change in the imaging contrast of the contacted surface, which also causes a rapid jump (ranging from a few to tens of picoamperes) of the grounding current. Thus, the detection of contact can be carried out in both qualitative and quantitative manners, providing a basis for establishing relevant standard procedures. In addition, we have achieved the spatial mapping of the contact point(s) using a specially designed lithographical pattern with two mutually vertical sets of parallel conductive lines. The precision of this mapping technique is simply determined by the pitch of parallel lines, which can be as small as the capability achievable in e-beam lithography. A possible “one-probe” version of the electrical characterization is also discussed with the same underlying principle, which may turn out to be indispensable for various studies and applications of nanostructures. Further development along this track is promising to realize an instrumentally simple version of “scanning electron spectroscopy” with various modes.
Quantum dynamics study of the dissociative photodetachment of HOCO−
Authors: Zhang Shesheng , Medvedev Dmitry M. , Goldfield Evelyn M. , Gray Stephen K.
Published: October 2006

Six-dimensional wave packet calculations are carried out to study the behavior of HOCO subsequent to the photodetachment of an electron from the negative anion, HOCO−. It is possible to form stable and/or long-lived HOCO complexes, as well as the dissociative products OH+CO and H+CO2. A variety of observables are determined: the electron kinetic energy (eKE) distributions associated with the OH+CO and H+CO2 channels, the correlated eKE and product translational energy distribution for the OH+CO channel, and product branching ratios. Most of our results are in good accord with the experimental results of Clements, Continetti, and Francisco [J. Chem. Phys. 117, 6478 (2002)], except that the calculated eKE distribution for the H+CO2 channel is noticeably colder than experiment. Reasons for this discrepancy are suggested.
A new molecular thermodynamic model for multicomponent Ising lattice
Authors: Yang Jianyong , Xin Qin , Sun Lei , Liu Honglai , Hu Ying , Jiang Jianwen
Published: October 2006

A new molecular thermodynamic model is developed for multicomponent Ising lattice based on a generalized nonrandom factor from binary system. Predictions of the nonrandom factor and the internal energy of mixing for ternary and quaternary systems match accurately with simulation results. Predictions of liquid-liquid phase equilibrium for ternary systems are in nearly perfect agreement with simulation results, and substantially improved from Flory-Huggins theory and the lattice-cluster theory. The model also satisfactorily correlates the experimental data of real ternary systems. The concise expression and the accuracy of the new model make it well suited for practical engineering applications.
HF in clusters of molecular hydrogen: II. Quantum solvation by H2 isotopomers, cluster rigidity, and comparison with CO-doped parahydrogen clusters
Authors: Sebastianelli Francesco , Elmatad Yael S. , Jiang Hao , Bačić Zlatko
Published: October 2006

We present a comprehensive theoretical study of the quantum solvation of the HF molecule by small clusters of the H2 isotopomers, p-H2, HD, and o-D2, with up to 13 hydrogen solvent molecules. This complements our earlier work on the HF-doped parahydrogen clusters [H. Jiang and Z. Bačić, J. Chem. Phys. 122, 244306 (2005)]. The ground-state properties of the clusters are calculated exactly using the diffusion Monte Carlo method. Detailed information is obtained regarding the size and isotopomer dependences of the energetics, vibrationally averaged structures, and their rigidity. The rigidity of these clusters is investigated further by analyzing the distributions of their principal moments of inertia from the diffusion Monte Carlo simulations. The clusters are found to be rather rigid, especially when compared with the pure parahydrogen clusters of the same size. Extensive comparison is made with the quantum Monte Carlo results for the CO-doped parahydrogen clusters and significant differences are observed in the size evolution of certain properties, notably the chemical potential.
A computational study of the coalescence between a drop and an interface in Newtonian and viscoelastic fluids
Authors: Yue Pengtao , Zhou Chunfeng , Feng James J.
Published: October 2006

A drop falling onto a fluid-fluid interface may not merge with it at once but may undergo a so-called partial coalescence cascade. Experimental observations of this phenomenon have revealed fascinating features of the process for Newtonian as well as polymeric fluids. In this paper, we describe numerical simulations of partial coalescence based on a phase-field method. Results show that partial coalescence occurs for an intermediate range of drop sizes, and proceeds in two stages: capillary waves propagating along the drop and transforming it into a fluid column, and neck formation on the column and pinch-off of the secondary drop. In the first stage, interfacial energy turns into kinetic energy following film rupture, while in the second, the kinetic energy overcomes an energy barrier due to the initial increase in interfacial area during neck formation. A parametric study establishes a criterion for partial coalescence in terms of a maximum Ohnesorge number that applies to a wide range of fluid densities and viscosities as long as the Bond number is small. Viscoelasticity in either the drop or the matrix tends to delay the pinch-off of the secondary drop, and may even suppress partial coalescence altogether. The underlying mechanism is large tensile polymer stresses resisting the stretching and thinning of the fluid neck. The numerical results are in qualitative, and in some cases quantitative, agreement with prior experiments.
Combined effect of a single grain boundary and artificial pinning centers on the critical current density in a YBa2Cu3O7−δ thin film
Authors: Horide T. , Matsumoto K. , Yoshida Y. , Mukaida M. , Ichinose A. , Horii S.
Published: October 2006

The combined effect of a single grain boundary and artificial pinning centers (APCs) on the critical current density (Jc) in YBa2Cu3O7−δ thin films was investigated. The authors decorated the surface of a 5°-tilt bicrystal SrTiO3 substrate with Y2O3 nanoislands to introduce APCs into the film. Jc of the bicrystal YBa2Cu3O7−δ film with APCs was measured in various magnetic fields. The APCs improved Jc in high magnetic fields, but not in low magnetic fields due to the existence of the grain boundary. The limiting mechanism of Jc in the bicrystal film containing APCs is discussed based on the experimental results.
Surface breaking crack evaluation with photorefractive quantum wells and laser-generated Rayleigh waves
Authors: Matsuda Youichi , Nakano Hidetoshi , Nagai Satoshi , Hiratsuka Hajime
Published: October 2006

An adaptive laser ultrasound system using optical two-wave mixing technique with photorefractive quantum wells is developed for crack characterization in noisy environments. AlGaAs∕GaAs photorefractive multiple quantum wells featuring a quick response time of 9.1μs cancel disturbances below 100kHz. A laser-generated Rayleigh wave in a thermoelastic regime is used for crack characterization. The positions and depths of artificial cracks, 3 and 5mm in depth and 0.2mm in width, were evaluated. The crack orientations were also determined using a shear wave that was generated through mode conversion of a Rayleigh wave at the crack tip.
Strong exciton-photon coupling in a microcavity containing layered perovskite semiconductors
Authors: Brehier A. , Parashkov R. , Lauret J. S. , Deleporte E.
Published: October 2006

The authors have realized a Pérot-Fabry microcavity containing a two-dimensional layered perovskite-type semiconductor, (C6H5C2H4–NH3)2PbI4, between a dielectric mirror and a metallic mirror. A strong coupling regime between the perovskite exciton and the confined photon mode has been evidenced at room temperature from angular-resolved reflectivity experiments. An anticrossing of 140meV is observed between the excitonic and cavity modes. (C6H5C2H4–NH3)2PbI4 having a self-organized multiple quantum well structure, they have determined the oscillator strength per quantum well of this structure: 4×1013cm−2, which is one order of magnitude higher than in conventional inorganic quantum wells.
Terminal organelle development in the cell wall-less bacterium
Mycoplasma pneumoniae
Authors: Hasselbring Benjamin M. , Jordan Jarrat L. , Krause Robert W. , Krause Duncan C.
Published: October 2006

Mycoplasmas are cell wall-less bacteria considered among the smallest and simplest prokaryotes known, and yet several species including
Mycoplasma pneumoniae
have a remarkably complex cellular organization highlighted by the presence of a differentiated terminal organelle, a membrane-bound cell extension distinguished by an electron-dense core. Adhesin proteins localize specifically to the terminal organelle, which is also the leading end in gliding motility. Duplication of the terminal organelle is thought to precede cell division, but neither the mechanism of its duplication nor its role in this process is understood. Here we used fluorescent protein fusions and time-lapse digital imaging to study terminal organelle formation in detail in growing cultures of
M. pneumoniae
. Individual cells ceased gliding as a new terminal organelle formed adjacent to an existing structure, which then migrated away from the transiently stationary nascent structure. Multiple terminal organelles often formed before cytokinesis was observed. The separation of terminal organelles was impaired in a nonmotile mutant, indicating a requirement for gliding in normal cell division. Examination of cells expressing two different fluorescent protein fusions concurrently established their relative order of appearance, and changes in the fluorescence pattern over time suggested that nascent terminal organelles originated
de novo
rather than from an existing structure. In summary, spatial and temporal analysis of terminal organelle formation has yielded insights into the nature of
M. pneumoniae
cell division and the role of gliding motility in that process.
Intra-Urban Variations in Unemployment Duration: A Case Study
Authors: McGregor Alan
Published: October 2006

The paper examines variations in unemployment duration between job-seekers from a deprived urban area and a control group drawn from adjoining areas. The basic hypothesis is that the concentration of 'problem families' in the deprived estate leads to the stigmatisation of the area. Some employers then tend to screen out workers with an address in the deprived estate. Our statistical analysis shows that even after correcting for variations in personal characteristics between the two samples the job-seekers from the deprived area still experience significantly longer durations of unemployment than their counterparts in adjoining areas.
Industrial Decline and Unemployment in the Inner City Areas of Great Britain: a Review of the Evidence
Authors: Elias Peter , Keogh Geoffrey
Published: October 2006

This article examines empirical studies which have investigated problems of decentralisation, employment decline and the high levels of unemployment which prevail in the inner city areas of Britain. An attempt is made to synthesise these studies and to expose gaps in the current body of knowledge. The article concludes by interpreting the findings in relation to present policies towards inner city employment.
The Effects of a New Subway Line on Housing Prices in Metropolitan Toronto
Authors: Bajic Vladimir
Published: October 2006

An analysis by means of using the estimation results of a modal choice model and the hedonic price regressions model is conducted in order to identify the effects of a subway line in Toronto on the values of housing units. The modal choice model is used for the estimation of the direct benefits from the improvement in transportation, and the hedonic price equations for the identification of subway effects on housing prices. Empirical results indicate that the direct savings in commuting costs have been capitalized into housing values.
If Planning is Anything, Maybe it Can be Identified
Authors: Reade E.
Published: October 2006

Summary. A number of writers have pointed out that the word 'planning' is used so loosely that it can describe almost any approach to policy-making or decision-making. This paper asks whether it is in fact possible to identify planning as an analytically distinct method of informing and making public policies and decisions. (Clearly, it will not be empirically distinct, since in practice, policies and decisions will also reflect the influence of other 'methods', such as relying upon the market, or upon the ballot box). To permit the examination of this question, four such analytically distinct methods of decision-making, of which planning is one, are each set out in ideal-type form. Planning, since it is less readily comprehended, is set out in more detail than are the other three. This is done by breaking it down into its most characteristic 'constituent ideas'. Examination of these 'constituent ideas' of planning thought suggests that they fall into two groups. Firstly, we can distinguish a collection of ideas, each of which has intellectual credibility, but none of which seems logically or empirically to be the prerogative of planning; any policy-making, planned or unplanned, would seem able to make use of them. Secondly we can distinguish among the 'constituent ideas' of planning thought a group which are not intellectually credible, since their meaning is unclear. It is therefore concluded that planning cannot be an analytically distinct method of informing and making public policies and decisions.
Toward Estimating the Incidence of Journey-to-Work Costs
Authors: Kasper Hirschel
Published: October 2006

The purpose of this paper is to estimate the extent to which the daily travel to work costs are passed forward to employers in the form of higher wages. The incidence is estimated from a sample of Glasgow, Scotland workers who relocated their residences within the city. It was found that the elasticity of wages with respect to travel costs is greater than zero for both men and women and, perhaps, as much as one for men. Since the relocation within the city led to substantial job change, it would seem that wages should be expected to adjust to changes in policy areas such as transport and land zoning which make it cheaper or more expensive for workers to get to employment opportunities.
Urban and Regional Change, Migration and Commuting — The Dynamics of Workplace, Residence and Transport Choice
Authors: Vickerman R.W.
Published: October 2006

A key factor in the spatial structure of metropolitan areas is the relationship between workplace and residential location. This is particularly critical in any attempt to model the changes in structure which result from intra-metropolitan moves of employment and households. This paper attempts to provide a more satisfactory framework for understanding the dynamics of these changes. Empirical evidence is presented for the London region based on both aggregate data from unpublished Census material and the Greater London Transportation Study and disaggregate survey material from a specially commissioned household interview survey.
The Housing Market of the Budapest Urban Region 1949-1983
Authors: Sillince J.A.A.
Published: October 2006

By the late fifties reserves of infrastructure and labour in Budapest were becoming exhausted and it was decided to divert potential Budapest-bound migrants to other centres, developed with government help, outside commuting range of the capital. The urban hinterland was rapidly urbanised, without a plan and lacking basic infrastructure. Some evidence suggests that this urbanisation would have occurred even if the 1958 restrictions on residence in Budapest had not been imposed. In 1971 various housing reforms were instituted to reduce tensions in the housing market. These included rent rises and special treatment for needy cases. Although it has been suggested that these housing market tensions and the effects of housing reforms since 1971 have caused increased social class segregation in the Budapest urban region, Census data shows continuously declining social class segregation. This may be because continuously low housing costs, (never more than 6% of personal income for all social groups), and the fact that environmental and district social class is not reflected in house prices has led to a dilution of pre-existing social class segregation.
Redundancy in an Expanding Labour Market: A Case-study of Displaced Workers from Two Manufacturing Plants in Southampton
Authors: Pinch Steven , Mason Colin
Published: October 2006

Previous studies of redundancy have been derived from a restricted geographical base; they have been predominantly concerned with workers made redundant by manufacturing firms in older industrial regions and have largely ignored redundancies in more buoyant labour market areas. This paper examines the post-redundancy experience of workers made redundant by two large manufacturing firms in Southampton in the mid-1980s. Comparison with previous studies of redundancy in less prosperous labour markets in northern regions of the UK highlights contrasts in the proportions of workers finding alternative employment and in rates of pay, working conditions and levels of job satisfaction. The study also highlights the importance of gender in post-redundancy experience, another factor that has been neglected in previous studies.
Rural Industrialisation in Denmark and the Role of Public Policy
Authors: Jensen-Butler Chris
Published: October 2006

During the 1970s and 1980s major relocation of Danish industry took place to both rural and peripheral areas in Denmark, and the causes of this are examined. The paper looks at the role of public policy in this process, both explicitly regional policy and also economic and social policy having differing regional effects. A marked change in the nature of policy in the mid-1980s is identified, moving from a cost-support policy to a more offensive innovatory policy. However, the conclusion remains that public policy is not a major cause of the new locational trends.
The Municipal Wage and Employment Effects of Public Infrastructure
Authors: Duffy-Deno Kevin T. , Dalenberg Douglas R.
Published: October 2006

We empirically examine the relationship between public capital and municipal employment levels and changes using a sample of 48 large US cities during the 1970-80 period. We find greater stocks of public capital are associated with a higher demand for and supply of municipal workers. Holding all other factors constant, the effect of a 10 per cent greater level of per capita public capital stock is a 0.6 and 12.9 per cent higher demand for and supply of municipal workers in the short run. Reduced form estimates indicate a net positive effect on municipal employment but no net effect on municipal wages. These findings are supported by a fixed-effect model estimation.
Determining the Impact of Economic Factors on Local Government Growth Policy: Using Time-series Analysis and Transfer Function Models
Authors: McGinnis Harry
Published: October 2006

Being able to predict building activity is important to public administrators and planners. It has been widely established that there is a significant relationship between economic/ financial factors and local government growth policy as measured by building activity. This paper describes and analyses this relationship through the use of time-series methodology. Monthly data for input variables (unemployment rate and prime interest rate) are related to output variables (the monthly issuance of single-family building permits, commercial and industrial permits, total permits, and the estimated construction cost per single-family permit) using time-series intervention and transfer function analysis. Through the use of transfer functions, residential permit decisions, commercial and industrial permit activity and total permits issued for all uses are causally related to levels of unemployment and the prime rate with varying periods of delay before impact is felt in growth policy decisions.
Land Prices and Housing in Manila
Authors: Strassmann W. Paul , Blunt Alistair , Tomas Raul
Published: October 2006

For decades, exceptionally high land prices in Metropolitan Manila have co-existed with much vacant urban land. A 1991 survey of 3003 households suggests, however, that, by the standards of other countries, neither dwelling prices nor rents are high in Manila compared with family incomes. Relatively high land prices have instead led households to spend much less on structures and to accept low housing welfare although the availability of skilled construction labour, materials and finance has been fairly good and improving. Households must also endure much settlement insecurity and residential immobility worse than international norms. High land prices are related to negligible property taxation and to impediments to land markets and infrastructure development.
Commuting in Restructuring Urban Regions
Authors: Clark William A. V. , Kuijpers-Linde Marianne
Published: October 2006

A critical aspect of understanding changing urban structures in the late 20th century revolves around changes in urban transport generally and commuting specifically. How will the continuing deconcentration of large urban areas affect the links between work and residence and how will the changing spatial arrangements of large urban areas affect congestion and in turn the form of the 'new' urban region? The debates about future spatial forms are examined within the context of a case-study of the Randstad and the Southern Californian urban region. The tentative conclusions of the empirical analysis point to a strengthening of policentric structures. At the same time, increasing affluence, greater dependence on the automobile (even in the Netherlands) will in the short term at least, increase congestion. Thus the commuting paradox, shorter commutes but increasing congestion, is a function of urban spatial restructuring and the preference for the private car.
Normal Structure, Function, and Histology of Mucosa-Associated Lymphoid Tissue
Authors: Cesta Mark F.
Published: October 2006

The mucosa-associated lymphoid tissue (MALT) initiates immune responses to specific antigens encountered along all mucosal surfaces. MALT inductive sites are secondary immune tissues where antigen sampling occurs and immune responses are initiated. Effector sites, present as diffuse lymphoid tissue along all mucosal surfaces are the sites of IgA transport across the mucosal epithelium. Though there are many differences between inductive sites in various organs, they all contain the same basic compartments—follicles, interfollicular regions, subepithelial dome regions, and follicle-associated epithelium. The morphologic differences between MALT and other secondary lymphoid tissues, between the MALT sites of differing anatomic locations, and species differences among laboratory animals are described. The morphologic changes in MALT associated with aging, route of nutrition, and genetic mutation (i.e., the nude and SCID mutations) are also discussed. MALT tissues comprise the mucosal immune system which can function independently of the systemic immune system and are, therefore, an important and often overlooked aspect of immunopathology.
Normal Structure, Function and Histology of the Thymus
Authors: Pearse Gail
Published: October 2006

The thymus, a primary lymphoid organ and the initial site for development of T cell immunological function, is morphologically similar across species. It is actually an epithelial organ in which its epithelial cells provide a framework containing T cells as well as smaller numbers of other lymphoid cells. A symbiotic interaction exists between the thymic microinvironment and developing T cells, and the specificity of T cell release into the systemic circulation is under thymic control. The thymic cortex in a young animal is heavily populated by developing T cells along with a smaller proportion of associated epithelial cells. Larger, more mature T cells are found in the medulla where epithelial and other cell types are more abundant. Understanding normal morphological features of the thymus and their perturbations provides a cornerstone to assessing immune system function.
Enhanced Histopathology of Mucosa-Associated Lymphoid Tissue
Authors: Elmore Susan A.
Published: October 2006

The secretory epithelial surfaces of the body are a major route of entry for potentially pathogenic substances. The organized mucosal lymphoid tissues that are found within the gastrointestinal and respiratory tracts are therefore particularly important as a first line of defense against harmful compounds. The major function of these mucosa-associated lymphoid tissues (MALT) is to initiate local IgA immune responses, which are then passed on to draining lymph nodes. For enhanced histopathology, the separate compartments of each lymphoid tissue should be evaluated separately for changes in size and lymphocyte cellularity and descriptive rather than interpretive terminology should be used to characterize any changes. The organization of MALT is similar to that of lymph nodes with B-cell-rich follicles and T-cell-rich interfollicular areas. Therefore, these two compartments should be evaluated separately for changes in size and lymphocyte cellularity and the germinal center development within lymphoid follicles should be evaluated as well.
Histopathology of the Thymus
Authors: Pearse Gail
Published: October 2006

The thymus is a primary lymphoid organ that manifests dynamic physiological changes as animals age in addition to being exquisitely sensitive to stress and toxic insult. It is typically the first lymphoid tissue to respond to immunotoxic xenobiotics, with the first change being loss of cortical lymphocytes by apoptosis. This is followed by removal of the apoptotic cellular debris and, in the absence of recovery, may lead to loss of the corticomedullary demarcation and organ atrophy. Nonneoplastic proliferative changes include focal lymphoid hyperplasia and proliferation of medullary epithelial cells, often with formation of ribbons, cords, or tubules. Thymomas are relatively rare tumors that exhibit a wide spectrum of morphologic types but do not metastasize. Thymic lymphomas are common in some mouse strains and can become leukemic with hematogenous spread throughout the body.
Screening for Multidrug-Resistant Bacteria as a Predictive Test for Subsequent Onset of Nosocomial Infection
Authors: Galoisy-Guibal L. , Soubirou J. L. , Desjeux G. , Dusseau J. Y. , Eve O. , Escarment J. , Ecochard R.
Published: October 2006

Objective.

To investigate whether carriage of multidrug-resistant bacteria is a risk factor for nosocomial infection and whether detection of carriage is predictive of subsequent onset of nosocomial infection.

Methods.

In this observational cohort (study period, June 1998 through October 2002), nasal and rectal swab specimens from 412 consecutive patients admitted to the intensive care unit were tested for carriage of multidrug-resistant bacteria. Concomitantly, the bacteria responsible for any subsequent nosocomial infection, the date of infection, and some of the known clinical risk factors for nosocomial infection were noted. These factors were adjusted for potential confounders, using a Cox model stratified on the propensity score of multidrug-resistant bacteria carriage. The diagnostic characteristics of a carriage test, including the positive and negative diagnostic likelihood ratios, were calculated for all strata of the propensity score.

Results.

Forty-two patients were carrying multidrug-resistant bacteria. Nosocomial infection occurred in 95 patients, of whom 16 (38%) were carriers, and 79 (83%) were noncarriers (P = .01). After adjustment for potential confounders, statistical analysis revealed that carriage remained a risk factor for nosocomial infection (relative risk, 2.08 [95% confidence interval {CI}, 1.13-3.81]). Receipt of antibiotic treatment at the time of intensive care unit admission was found to be protective against nosocomial infection. A positive result of test for detection of carriage seemed to be an efficient predictor of subsequent nosocomial infection (positive diagnostic likelihood ratio, 2.05 [95% CI, 1.15-3.66]), although a negative test result was not a predictor of subsequent nosocomial infection (negative likelihood ratio, 0.91 [95% CI, 0.73-1.11]).

Conclusion.

Carriage proved to be a risk factor for subsequent nosocomial infection. However, the carriage test was useful as a predictive tool only for patients with a positive test result.
Methicillin-Resistant Staphylococcus aureus Survival on Hospital Fomites
Authors: Huang Robert , Mehta Sanjay , Weed Diane , Price Connie Savor
Published: October 2006

We examined the duration of survival of 2 strains of methicillin-resistant Staphylococcus aureus (MRSA) on 3 types of hospital fomites. MRSA survived for 11 days on a plastic patient chart, more than 12 days on a laminated tabletop, and 9 days on a cloth curtain. Irregular surfaces may help harbor organisms in the environment. In addition to contact precautions, MRSA containment during an outbreak should include concurrent environmental decontamination.
Transmission of Group A Streptococcus Limited to Healthcare Workers with Exposure in the Operating Room
Authors: Chandler Rebecca E. , Lee Lore E. , Townes John M. , Taplitz Randy A.
Published: October 2006

Background.

Nosocomial transmission of group A Streptococcus (GAS) has been well described. A recent report of an outbreak investigation suggested that transmission can be extensive and that standard infection control measures may not be adequate to prevent transmission from patients with severe, invasive disease to healthcare workers (HCWs).

Objective.

A case of pharyngitis in an HCW caring for a patient with GAS pharyngitis and necrotizing fasciitis prompted an investigation of the extent and risk factors for nosocomial transmission of GAS.

Setting.

A 509-bed, tertiary care center in Portland, Oregon with 631,100 patient visits (hospital and clinic) and 11,500 employees in the year 2003.

Methods.

HCWs with exposure to the index patient (“contacts”) were identified for streptococcal screening and culture and completion of a questionnaire regarding the location and duration of exposure, use of personal protective equipment, and symptoms of GAS infection.

Results.

We identified 103 contacts of the index patient; 89 (86%) submitted oropharyngeal swabs for screening and culture. Only 3 (3.4%) of contacts had a culture that yielded GAS; emm typing results and pulsed-field gel electrophoresis patterns of GAS isolates from 2 HCWs were identical to those for the isolate from the index patient. Both HCWs were symptomatic, with febrile pharyngitis and reported prolonged contact with the open wound of the patient in the operating room.

Conclusions.

In this investigation, nosocomial transmission was not extensive, and standard precautions provided adequate protection for the majority of HCWs. Transmission was restricted to individuals with prolonged intraoperative exposure to open wounds. As a result, infection control policy for individuals was modified only for HCWs with exposure to GAS in the operating room.