bluuebunny/crossref_metadata_2025 huggingface dataset:
Cardiac PPARα expression in patients with dilated cardiomyopathy
Authors: Schupp Michael , Kintscher Ulrich , Fielitz Jens , Thomas Jennifer , Pregla Reinhard , Hetzer Roland , Unger Thomas , Regitz‐Zagrosek Vera
Published: November 2005

Background:

The peroxisome proliferator‐activated receptor alpha (PPARα) is a central regulator of myocardial fatty acid (FA) metabolism implicated in the pathogenesis of heart failure.

Aims:

To characterize PPARα regulation in human dilated cardiomyopathy (DCM), we studied the expression of cardiac PPARα, cardiac carnitine palmitoyl‐transferase I (CPT‐1), a major PPARα target gene, and of the cardiac glucose transporter GLUT‐4 in patients with DCM.

Methods:

Left ventricular biopsies were taken from patients with DCM (n=16) and control subjects (n=15), and mRNA expression was quantitated using real‐time PCR (SYBR®Green) and protein expression was measured by Western immunoblotting.

Results:

Left ventricular PPARα mRNA levels were significantly increased in the DCM group compared to the control group (136±25.4% vs. control, p<0.01). Consistently, DCM patients had a significantly higher cardiac CPT‐1 mRNA expression (147±51% vs. control, p<0.05) compared to the control group. Cardiac GLUT‐4 expression was similar in both groups.

Conclusion:

Elevated cardiac PPARα levels followed by an induction of cardiac CPT‐1 expression may result in increased fatty acid metabolism for cardiac energy production in DCM, suggesting a specific cardiac metabolic program in human DCM compared to other types of cardiomyopathy.
KNOWLEDGE, ATTITUDE AND PRACTICE TOWARDS HIV/AIDS IN A RURAL KENYAN COMMUNITY
Authors: KARAMA MOHAMED , YAMAMOTO TARO , SHIMADA MASAAKI , ORAGO S. S. A. , MOJI KAZUHIKO
Published: November 2005

The aim of this research was to explore people’s knowledge, attitude, behaviour and practice towards HIV/AIDS and sexual activity in rural Kenya, where HIV is widespread. The study community was located in south-eastern Kenya, 50 km north of Mombassa, and had an estimated population of 1500. Subjects aged between 16 and 49 were recruited using a stratified cluster-sampling method and they completed self-administered questionnaires.Almost all respondents knew the word ‘HIV’. Around 50% knew of a person living with HIV. About 80% gave ‘death’ or ‘fear’ as words representing their image of AIDS. With regard to sexual activity, the distribution of answers to the question ‘how many partners have you ever had in your life’ was bimodal in males but had only one peak in females, indicating that some men have a large number of sexual partners in their lifetime. First sexual intercourse was at around 12–13 years for both sexes, but female teenagers were more sexually experienced than their male counterparts.
What, if anything, are colours
relative to?
Authors: Hyman John
Published: November 2005

The questions considered are whether colours are relative to systems of colour concepts, to the conditions in which they are observed, or to observers or communities of observers; and whether the relativity of colours, such as it is, implies that they are less real than shapes or intervals in time. The argument is based on the thought that Special Relativity provides the best available intellectual framework for thinking about the supposed relativity of qualities of physical things.
Ethno-psychometric evaluation of the General Health Questionnaire in rural China
Authors: LEE DOMINIC T. S. , YIP WINNIE C. M. , CHEN YENFONG , MENG QINGYUE , KLEINMAN ARTHUR
Published: November 2005

Background. Most mental health research tools are developed in Western, urban contexts. Few studies have evaluated the applicability of these research tools in rural populations of non-Western countries. We examined the cultural acceptance and psychometric performance of the 12-item General Health Questionnaire (GHQ) in China's rural villages.

Method. Ethnographic investigations were conducted to assess the cultural applicability of self-report rating scales among villagers. This was followed by a survey of 1401 rural residents, randomly selected from 48 villages of Shandong province using stratified multistage cluster sampling. The respondents were administered the GHQ and the Composite International Diagnostic Interview (CIDI).

Results. The GHQ, when administered by trained interviewers, was culturally acceptable to rural residents. The scale had good psychometric properties in the study population. The area under the curve was 0·86. At a cut-off of 1/2, the sensitivity and specificity were 80·6% and 79·3% respectively.

Conclusions. The ethno-psychometric evaluation showed that the GHQ was both culturally valid and psychometrically sound in the Chinese rural context.
No evidence of time trends in the urban–rural differences in schizophrenia risk among five million people born in Denmark from 1910 to 1986
Authors: PEDERSEN CARSTEN BØCKER
Published: November 2005

Background. There have been conflicting reports on time trends in urban–rural differences in the incidence of schizophrenia. This study explored the potential time trends in these differences with regard to birth cohort and age at onset.

Method. Linking data from the Danish Civil Registration system with data from the Danish Psychiatric Central Register, a cohort born in Denmark from 1910 to 1986 was established (5·05 million people). Overall, 23051 people were classified with schizophrenia in 1970–2001.

Results. Urban–rural differences in schizophrenia risk may have existed for people born in Denmark since 1910, and have existed at a constant level for people born from 1945 to 1986. Males aged <20 years had a risk of 3·90 [95% confidence interval (CI) 3·28–4·65] associated with urban birth while males [ges ]20 years had a risk of 2·12 (1·98–2·27). Females <20 years had a risk of 2·49 (95% CI 2·01–3·09) associated with urban birth while females [ges ]20 years had a risk of 1·90 (95% CI 1·74–2·08). At age 46, 1·84% (95% CI 1·76–1·93) of males and 1·05% (95% CI 0·99–1·12) of females born in the capital area had developed schizophrenia, while 0·81% (95% CI 0·75–0·86) of males and 0·56% (95% CI 0·51–0·60) of females born in the rural area had developed schizophrenia.

Conclusions. There was no evidence of time trends in the urban–rural differences in the incidence of schizophrenia in Denmark, suggesting that the cause(s) responsible for these differences were not related to exposures that became more prevalent in urban areas over time. This finding is in contrast to findings from Finland and The Netherlands.
Joint angle variations analyses of the two link planar manipulator in welding by using inverse kinematics
Authors: Bulut S. , Terzioǧlu M. B.
Published: November 2005

In this paper, the joint angles of a two link planar manipulator are calculated by using inverse kinematics equations together with some geometric equalities. For a given position of the end-effector the joint angle and angular velocity of the links are derived. The analyses contains many equations which have to be solved. However, the solutions are rather cumbersome and complicated, therefore a program is written in Fortran 90 in order to do, the whole calculation and data collection. The results are given at the end of this paper.
WHAT DO ECONOMISTS ANALYZE AND WHY: VALUES OR FACTS?
Authors: DASGUPTA PARTHA
Published: November 2005

Social thinkers frequently remind us that people differ in their views on what constitutes personal well-being, but that even when they don't differ, they disagree over the extent to which one person's well-being can be permitted to be traded off against another's. In this paper I show, by offering an account of the development of development economics, that in professional debates on social policy, economists speak or write as though they agree on values but differ on their reading of facts. A number of ethicists have concluded from this near-exclusive interest in facts that modern economics must be an ethical desert. It is shown here that the reason research economists analyze facts rather than values is that modern economics is built on broad ethical foundations, capable of being reduced as special cases to the various ethical theories that are currently on offer. Ethics has taken a back seat in modern economics not because contemporary economists are wedded to a “value-free” enterprise, but because the ethical foundations of the subject were constructed over five decades ago and are now regarded to be a settled matter.
PROPERTY RIGHTS AND THE RIGHT TO THE FRUITS OF ONE'S LABOR: A NOTE ON ADAM SMITH'S JURISPRUDENCE
Authors: WITZTUM AMOS
Published: November 2005

This paper provides further evidence to the argument that Smith' theory of justice did not follow the natural justice school and that subsequently the ethical position on acquiring private property is not independent of the effects which such acquisition may have on the property-less individuals. I will show that the justification for private ownership is based on “reasonable expectations” which owners of assets have with regard to the fruits of the asset. The expectation to subsist through the use of one's natural assets is equally reasonable. This is not to say that Smith believed that society should equally distribute income. But it does mean that the acquisition of private property must not interfere with the rights of individuals to subsist. Consequently, distribution is clearly an important part of Smith's conception of justice.
STABILITY AND CYCLES IN A COBWEB MODEL WITH HETEROGENEOUS EXPECTATIONS
Authors: LASSELLE LAURENCE , SVIZZERO SERGE , TISDELL CLEM
Published: November 2005

We investigate the dynamics of a cobweb model with heterogeneous beliefs, generalizing the example of Brock and Hommes (1997). We examine situations where the agents form expectations by using either rational expectations, or a type of adaptive expectations with limited memory defined from the last two prices. We specify conditions that generate cycles. These conditions depend on a set of factors that includes the intensity of switching between beliefs and the adaption parameter. We show that both Flip bifurcation and Neimark–Sacker bifurcation can occur as primary bifurcation when the steady state is unstable.
Charakterisierung kognitiver Einbußen von Patienten mit “Mild Cognitive Impairment” (MCI) in der CERAD- Screeningbatterie
Authors: Schreiber Yvonne A. , Ackl Nibal , Sonntag Annette , Zihl Josef
Published: November 2005

Zusammenfassung: Die frühzeitige Diagnose kognitiver Abbauprozesse ist vor dem Hintergrund der “alternden Gesellschaft” von enormer Bedeutung. In der vorliegenden Arbeit wurde das Potenzial der CERAD-kognitiven Screeningbatterie als Untersuchungsprotokoll zur Diagnostik leichter kognitiver Beeinträchtigungen (MCI, Petersen et al., 1995 ) sowie als Verlaufsinstrument überprüft. Die Leistungen von 51 MCI-Patienten wurden mit 81 gesunden Kontrollpersonen verglichen. Die Leistungen der MCI-Gruppe unterschied sich in nahezu allen Subtests der CERAD-Batterie signifikant von denen der Kontrollgruppe. In der Verlaufsuntersuchung an einer Teilstichprobe (n = 18) fanden sich hingegen in der CERAD-Batterie keine signifikanten Veränderungen. Zusammenfassend lässt sich feststellen, dass die CERAD-Batterie bei leichten kognitiven Beeinträchtigungen ein ausreichend valides Screeninginstrument darstellt; für Verlaufsuntersuchungen scheint sie hingegen weniger gut geeignet zu sein.
Gamma-Aktivität
Authors: Herrmann Christoph S.
Published: November 2005

Zusammenfassung: Aufgrund ihrer niedrigen Amplitude wird die Bedeutung hochfrequenter EEG-Oszillationen für die Psychopathologie gegenüber niederfrequenten aber höheramplitudigen Oszillationen oft unterschätzt. Psychophysiologische Experimente an Mensch und Tier haben eindrucksvoll den Zusammenhang zwischen so genannten Gamma-Oszillationen (ca. 30-80 Hz) und kognitiven Funktionen nachgewiesen. Das synchrone Feuern von Neuronen im Gamma-Band ermöglicht das Zusammenbinden von getrennt repräsentierten Merkmalen wahrgenommener Objekte aus der Umwelt. Die Gamma-Aktivität zeigt aber bereits bei Gesunden eine deutliche interindividuelle Variation, die mit der Ausprägung kognitiver Merkmale korreliert. Bei schizophrenen Patienten konnte ein Mangel an synchroner Gamma-Aktivität beobachtet werden, der für negative Symptome verantwortlich gemacht wird. Umgekehrt wurde bei Epileptikern erhöhte Gamma-Aktivität im EEG registriert, was die erhöhte Erregbarkeit des Kortex widerzuspiegeln scheint. Auch bei ADHS tritt eine geringfügige Erhöhung von Gamma-Oszillationen auf.
Analysis of ICESat data using Kalman filter and kriging to study height changes in East Antarctica
Authors: Nguyen A. T. , Herring T. A.
Published: November 2005

We analyze ICESat derived heights collected between Feb.03–Nov.04 using a kriging/Kalman filtering approach to investigate height changes in East Antarctica. The model's parameters are height change to an a priori static digital height model, seasonal signal expressed as an amplitude B and phase θ, and height‐change rate dh/dt for each (100 km)2 block. From the Kalman filter results, dh/dt has a mean of −0.06 m/yr in the flat interior of East Antarctica. Spatially correlated pointing errors in the current data releases give uncertainties in the range 0.06 m/yr, making height change detection unreliable at this time. Our test shows that when using all available data with pointing knowledge equivalent to that of Laser 2a, height change detection with an accuracy level 0.02 m/yr can be achieved over flat terrains in East Antarctica.
Automated grain size measurements from airborne remote sensing for long profile measurements of fluvial grain sizes
Authors: Carbonneau Patrice E. , Bergeron Normand , Lane Stuart N.
Published: November 2005

Recent research has demonstrated that image processing can be applied to derive surficial median grain size data automatically from high‐resolution airborne digital imagery in fluvial environments. However, at the present time, automated grain size measurement is limited to the dry exposed bed areas of the channel. This paper shows that the application area of automated grain size mapping can be extended in order to include the shallow wetted areas of the channel. The paper then proceeds to illustrate how automated grain size measurement in both dry and shallow wetted areas can be used to measure grain sizes automatically for long river lengths. For the present study, this results in a median grain size profile covering an 80 km long river which is constructed from over three million automated grain size measurements.
Effect of Long-Term Mild Hypothermia or Short-Term Mild Hypothermia on Outcome of Patients with Severe Traumatic Brain Injury
Authors: Jiang Ji-Yao , Xu Wei , Li Wei-Ping , Gao Guo-Yi , Bao Ying-Hui , Liang Yu-Min , Luo Qi-Zhong
Published: November 2005

To compare the effect of long-term mild hypothermia versus short-term mild hypothermia on the outcome of 215 severe traumatic brain injured patients with cerebral contusion and intracranial hypertension. At three medical centers, 215 patients aged 18 to 45 years old with an admission Glasgow Coma Scale ⩽ 8 within 4 h after injury were randomly divided into two groups: long-term mild hypothermia group ( n = 108) for 5 ± 1.3 days mild hypothermia therapy and short-term mild hypothermia group ( n = 107) for 2 ± 0.6 days mild hypothermia therapy. All patients had intracranial hypertension and frontotemporoparietal contusion with midline shift > 1 cm confirmed on computed tomographic scan. Glasgow Outcome Scale at 6-month follow-up, 47 cases had favorable outcome (43.5%), and other 61 cases had unfavorable outcome (56.5%) in the long-term mild hypothermia group. However, only 31 cases had favorable outcome (29.0%), and other 76 cases had unfavorable outcome (71.0%) in the short-term mild hypothermia group (P<0.05). The intracranial pressure significantly rebounded after rewarming in the short-term mild hypothermia group, but not in the long-term mild hypothermia (P<0.05). Furthermore, the incidence of stress ulcer, epilepsy, pulmonary infection, intracranial infection did not significantly differ between the two groups (P>0.05). Compared with short-term mild hypothermia, long-term mild hypothermia significantly improves the outcome of severe traumatic brain injured patients with cerebral contusion and intracranial hypertension without significant complications. Our data suggest that 5 days of long-term cooling is more efficacious than 2 days of short-term cooling when mild hypothermia is used to control refractory intracranial hypertension in patients with severe traumatic brain injury.
IUPAC-NIST Solubility Data Series. 81. Hydrocarbons with Water and Seawater—Revised and Updated. Part 8. C9 Hydrocarbons with Water
Authors: Goral Marian , Wisniewska-Goclowska Barbara , Skrzecz Adam , Owczarek Iwona , Blazej Krystyna , Haulait-Pirson Marie-Claire , Hefter Glenn T. , Kapuku F. , Maczynska Zofia , Szafranski Andrzej
Published: November 2005

The mutual solubility and related liquid-liquid equilibria of C9 hydrocarbons with water are exhaustively and critically reviewed. Reports of the experimental determination of solubility in 18 chemically distinct binary systems that appeared in the primary literature prior to the end of 2002 are compiled. For 8 systems, sufficient data are available to allow critical evaluation. All data are expressed as mass percent and mole fraction, as well as the originally reported units. In addition to the standard evaluation criteria used throughout the Solubility Date Series, a new method based on the evaluation of the all experimental data for a given homologous series of aliphatic and aromatic hydrocarbons was used.
Coalescence in semiconcentrated emulsions in simple shear flow
Authors: Korobko A. V. , van den Ende D. , Agterof W. G. M. , Mellema J.
Published: November 2005

The coalescence frequency in emulsions containing droplets with a low viscosity (viscosity ratio ∼0.005) in simple shear flow has been investigated experimentally at several volume fractions of the dispersed phase (2%–14%) and several values of the shear rate (0.1–10s−1). The evolution of the size distribution was monitored to determine the average coalescence probability from the decay of the total number of droplets. Theoretically models for two-droplet coalescence are considered, where the probability is given by Pc=exp(−τdr∕τint). Since the drainage time τdr depends on the size of the two colliding droplets, and the collision time τint depends on the initial orientation of the colliding droplets, the calculated coalescence probability was averaged over the initial orientation distribution and the experimental size distribution. This averaged probability was compared to the experimentally obtained coalescence frequency. The experimental results indicate that (1) to predict the average coalescence probability one has to take into account the full size distribution of the droplets; (2) the coalescence process is best described by the “partially mobile deformable interface” model or the “fully immobile deformable interface” model of Chesters [A. K. Chesters, Chem. Eng. Res. Des. 69, 259 (1991)]; and (3) independent of the models used it was concluded that the ratio τdr∕τint scales with the coalescence radius to a power (2±1) and with the rate of shear to a power (1.5±1). The critical coalescence radius Ro, above which hardly any coalescence occurs is about 10μm.
Enhancement of hydrogen physisorption on graphene and carbon nanotubes by Li doping
Authors: Cabria I. , López M. J. , Alonso J. A.
Published: November 2005

Density-functional calculations of the adsorption of molecular hydrogen on a planar graphene layer and on the external surface of a (4,4) carbon nanotube, undoped and doped with lithium, have been carried out. Hydrogen molecules are physisorbed on pure graphene and on the nanotube with binding energies about 80–90meV∕molecule. However, the binding energies increase to 160–180meV∕molecule for many adsorption configurations of the molecule near a Li atom in the doped systems. A charge-density analysis shows that the origin of the increase in binding energy is the electronic charge transfer from the Li atom to graphene and the nanotube. The results support and explain qualitatively the enhancement of the hydrogen storage capacity observed in some experiments of hydrogen adsorption on carbon nanotubes doped with alkali atoms.
Adsorption at the liquid-vapor surface of a binary liquid mixture
Authors: Whitmer J. K. , Kiselev S. B. , Law B. M.
Published: November 2005

In a binary liquid mixture, the component possessing the lowest surface tension preferentially adsorbs at the liquid-vapor surface. In the past this adsorption behavior has been extensively investigated for critical binary liquid mixtures near the mixture’s critical temperature Tc. In this fluctuation-dominated regime the adsorption is described by a universal function of the dimensionless depth z∕ξ where ξ is the bulk correlation length. Fewer studies have quantitatively examined adsorption for off-critical mixtures because, in this case, one must carefully account for both the bulk and surface crossover from the fluctuation-dominated regime (close to Tc) to the mean-field dominated regime (far from Tc). In this paper we compare extensive liquid-vapor ellipsometric adsorption measurements for the mixture aniline+cyclohexane at a variety of critical and noncritical compositions with the crossover theory of Kiselev and co-workers [J. Chem. Phys. 112, 3370 (2000)].
Plasma pressure effect on Alfvén cascade eigenmodes
Authors: Breizman B. N. , Pekker M. S. , Sharapov S. E. ,   JET EFDA contributors
Published: November 2005

Tokamak plasmas with reversed magnetic shear are prone to the excitation of Alfvén cascade (AC) eigenmodes by energetic particles. These modes exhibit a quasiperiodic pattern of predominantly upward frequency sweeping. Observations also reveal that the AC spectral lines sometimes bend at low frequencies, which is a significant deviation from the shear Alfvén wave dispersion relation. This paper shows that the underlying reasons for such bending are the finite pressure of the plasma and the geodesic curvature that precludes shear Alfvén perturbations from being strictly incompressible. In addition to the geodesic effect, there are two other pressure effects on shear Alfvén waves, which are the convection in the presence of an equilibrium pressure gradient and the toroidicity-induced coupling between shear Alfvén waves and acoustic modes. An analytical treatment of the problem enables a parametric comparison of all three mechanisms. The key distinction between the geodesic compressibility and the acoustic coupling is that geodesic compression occurs without plasma displacement along the magnetic-field lines. As a result, the mode phase velocity is greater than the ion thermal velocity even in an isothermal plasma, which allows the mode to avoid a strong ion Landau damping. Plasma temperature diagnostics via magnetohydrodynamic spectroscopy employing the low-frequency part of the ACs is suggested.
Subgrid modeling of anisotropic rotating homogeneous turbulence
Authors: Shao L. , Zhang Z. S. , Cui G. X. , Xu C. X.
Published: November 2005

We investigate subgrid modeling of anisotropic rotating turbulence with a dynamic equation of structure functions of the filtered velocity field. The local volume-averaged structure function equation of rotating turbulence is introduced and an eddy viscosity subgrid model is obtained. The resulting subgrid model is similar to that of the study of Cui et al. [Phys. Fluids 16, 2835 (2004)]. It is directly related to the transfer term: the third-order structure function. This term can be computed dynamically during large eddy simulations (LES). Tests are successfully carried out in LES of decaying, rotating, homogeneous turbulence at high Reynolds numbers. Results are in excellent agreement when compared with those of Cambon et al. [J. Fluid Mech. 337, 303 (1997)].
The ∇B drift velocity of trapped particles in stellarators
Authors: Nemov V. V. , Kasilov S. V. , Kernbichler W. , Leitold G. O.
Published: November 2005

In recent times, procedures for optimizing stellarator configurations have been strongly improved. New ideas and the development of pertinent codes allow an inclusion of various target functions into this optimization procedure. Here, new target functions which are related to collisionless α-particle confinement are introduced. They are based on specific averages of the bounce-averaged ∇B drift velocity of trapped particles across magnetic surfaces. This approach accompanies the frequently used computation of the effective ripple and it can be realized in a similar way using a field line tracing code. In addition, the poloidal motion of trapped particles is described in detail and results are discussed in the frame of an optimization study which aimed for a closure of contours of the second adiabatic invariant.
Synchronization of multiple spark-gap switches by a transmission line transformer
Authors: Liu Z. , Yan K. , Pemen A. J. M. , Winands G. J. J. , Van Heesch E. J. M.
Published: November 2005

A transmission line transformer (TLT)-based multiple-switch circuit topology was recently proposed for pulsed-power generation. By means of a TLT, multiple spark-gap switches can be synchronized in a short time (ns). It is attractive to be used to design a long-lifetime repetitive large pulsed-power source (100kW, 1kHz) for various kinds of applications, such as corona plasma-induced gas cleaning. To gain insight into the synchronization principle and switching behavior of the individual switch, an equivalent circuit model was developed and an experimental setup with two spark-gap switches and a two-stage TLT has been constructed. We observed that in terms of switching currents, the two switches can be synchronized within 2–3ns. The equivalent circuit model approximately fits the experimental results.
Coupling between upper-hybrid waves and electron holes in Earth’s magnetotail
Authors: Jovanović D. , Shukla P. K. , Morfill G.
Published: November 2005

An analytic theory of the nonlinear interaction between electrostatic high-frequency upper-hybrid waves and the low-frequency electron holes in a magnetized plasma is presented. It provides an explanation for the simultaneous occurrence of upper-hybrid bursts and electron holes, observed recently by the WIND and CLUSTER spacecrafts in the vicinity of the X point during the collisionless reconnection in Earth’s deep magnetotail. Using a fluid description for the high-frequency mode and a drift-kinetic description for the low-frequency mode, a Zakharov-type system of equations is obtained that describes the interaction between the upper-hybrid and lower-hybrid waves in the presence of an oblique Buneman instability and resonant electrons. The saturation of the linear and explosive parametric instabilities is shown to result from the electron trapping in the combined low-frequency and ponderomotive potentials, yielding an oblique lower-hybrid hole. The presence of an electron hole produces the localization of the upper-hybrid waves, yielding either a bright nonlinear Schrödinger soliton trapped inside the hole or a dark soliton driven by the defocusing nonlinear Schrödinger nonlinearity, which is trapped outside of the hole.
A general solution for space-charge limiting in one dimension
Authors: Preston Eric F. , Stringer Thomas A.
Published: November 2005

Computation of space-charge current-limiting effects across a vacuum cavity between parallel electrodes has previously been carried out only for thermionic emission spectra. In some applications, where the current arises from an injected electron beam or photo-Compton emission from electrode walls, the electron energy spectra may deviate significantly from Maxwellian. Considering the space charge as a collisionless plasma, we derive an implicit equation for the peak cavity potential assuming steady-state currents. For the examples of graphite, nickel, and gold electrodes exposed to x rays, we find that cavity photoemission currents are typically more severely space-charge limited than they would be with the assumption of a purely Maxwellian energy distribution.
Real-time profile of microcantilevers for sensing applications
Authors: Mertens J. , Álvarez M. , Tamayo J.
Published: November 2005

An optical readout technique has been developed for real-time monitoring of the profile of microcantilever arrays for sensing applications. The technique is based on the automated two-dimensional scanning of a laser beam by using voice-coil actuators. Cantilever profiles are obtained with subnanometer resolution and a processing speed of about ten cantilevers per second. The technique is applied for real-time monitoring of the adsorption of the alkylthiol mercaptohexanol in an aqueous environment by using an array of five microcantilevers. Molecular adsorption produces a cantilever strain that significantly differs from the Stoney’s model. Main strain changes are strongly located near the cantilever clamping.
Spectroscopic ellipsometry study of Cd1−xMnxTe∕CdTe superlattices
Authors: Bellani Vittorio , Stella Angiolino , Chen Chenjia , Wang Xuezhong
Published: November 2005

We studied, by means of spectroscopic ellipsometry, dilute magnetic Cd1−xMnxTe∕CdTe semiconductor superlattices and Cd1−xMnxTe thin films grown by molecular beam epitaxy. In superlattices, the pseudodielectric function measured by ellipsometry shows specific features related to the excitonic transition between quantized minibands. In thin films, ellipsometry allows the clear identification of the energy gap. Additionally, critical point transitions are observable both in the spectra of the superlattices and films. Photoluminescence experiments have also been measured in order to evidence the fundamental interminiband excitonic transitions in superlattices and the energy gap in thin films, respectively. The electronic structure of the superlattices has been calculated in the framework of the envelope function approximation and compared with the experimental spectra. Ellipsometry appears to be a suitable technique to monitor the molecular beam epitaxy growth, ultimately also in situ, of dilute magnetic low-dimensional semiconductor systems.
Measurements of thermally induced nanometer-scale diffusion depth of Pt∕Ti∕Pt∕Au gate metallization on InAlAs∕InGaAs high-electron-mobility transistors
Authors: Kim Seiyon , Adesida Ilesanmi , Hwang Heedon
Published: November 2005

Platinum diffusion in InAlAs was investigated utilizing a Pt∕Ti∕Pt∕Au gate contact on an In0.52Al0.48As∕In0.53Ga0.47As∕InP high-electron-mobility transistor (HEMT) structure. Capacitance-voltage measurements on large gate field-effect transistors and high-resolution cross-sectional transmission electron microscopy enabled the measurement of Pt diffusion depth with nanometer-scale accuracy. A continuous increase in Pt diffusion depth was observed at an annealing temperature of 250 °C with increasing time. After a 40 min anneal, a diffusion depth of 8 nm was measured. Such a deep Pt diffusion in a HEMT structure not only changes device parameters but also constitutes a serious reliability problem during device operation.
Recovery of time evolving fluorescence spectra via sum-frequency cross-correlation frequency resolved optical gating
Authors: Langdon Benjamin T. , Levinger Nancy E.
Published: November 2005

Sum-frequency conversion of sample emission with short light pulses has been used for time-resolved fluorescence of chromophores in solution. In contrast to traditional fluorescence upconversion techniques where the time resolved fluorescence signal is approximated from 10 to 15 different sum-frequency gated decays distributed across the fluorescence spectrum, sum-frequency cross-correlation frequency resolved optical gating offers the opportunity to determine the electric field of the sample fluorescence as a function of time. Dynamic quantities associated with changes in the sample emission, such as solvent relaxation, can then be obtained directly from the electric field without assumption of a particular spectral line shape.
Nanoconjunction of DNA-retained gold nanoparticles using silver
Authors: Lee Dong Hun , Kim Seol Ji , Heo Soo Yeon , Jang Du-Jeon
Published: November 2005

Oligonucleotide duplexes are utilized to retain gold nanoparticles adjacently and to associate Ag+ ions for the nanoconjunction of gold nanoparticles with silver. Junctions between adjoining gold nanoparticles connected by duplexes are well bridged with silver to have the crystalline structure of silver. Because Ag+ ions clustered around oligonucleotide duplexes are reduced on metallic surfaces, silver is produced preferably on gold surfaces near duplexes to solder gold nanoparticles with nanocontact.
Segregation-induced grain boundary premelting in nickel-doped tungsten
Authors: Luo J. , Gupta V. K. , Yoon D. H. , Meyer H. M.
Published: November 2005

High-resolution transmission electron microscopy and Auger spectroscopy have revealed the formation of nanometer-thick, Ni-enriched, disordered, grain boundary layers in Ni-doped W specimens at 95 °C below the bulk eutectic temperature. The stabilization of subeutectic liquid-like grain boundary cores in this model two-component metallic alloy is phenomenologically analogous to the long-sought phenomenon of grain boundary premelting. The existence of such disordered nanostructures at metallic grain boundaries provides insights to resolve several long-standing controversies in interpreting the unique grain boundary diffusion∕migration kinetics and mechanical properties for this system, and can have technological importance for a broader range of materials.
Nonvolatile multilevel conductance and memory effects in organic thin films
Authors: Lauters M. , McCarthy B. , Sarid D. , Jabbour G. E.
Published: November 2005

Organic thin-film structures, including organic light-emitting diodes, are demonstrated to contain multiple nonvolatile conductance states at low-read voltages. Retention time of states is more than several weeks, and more than 20 000 write-read-rewrite-read cycles have been performed with minimal degradation. The electrical characteristics of these devices are consistent with metal diffusion or filament phenomena found in metal-insulator-metal structures, suggesting a possible mechanism by which the states are stored.
Determinants of Fusion of Dichoptically Presented Orthogonal Gratings
Authors: Burke Darren , Alais David , Wenderoth Peter
Published: November 2005

Liu, Tyler, and Schor (1992 Vision Research32 1471–1479) reported the surprising finding that dichoptically presented orthogonal sine-wave gratings do not always produce binocular rivalry. Gratings of high spatial frequency, and especially of low contrast, fuse to produce a stable percept of a dichoptic plaid. Using a somewhat different perceptual task, we replicated those findings and extended them. The probability of a plaid percept is higher for square-wave gratings than for sine-wave gratings, and higher still for rectangular-wave gratings with high duty cycles (with very thin light or dark bars). Experiments were conducted to test whether this duty-cycle effect was due to changes in overall luminance, or in the size of the regions of luminance congruity (which may reduce the probability of rivalry), but no such effects could account for the results. The presence of locally conflicting contour information in the two eyes was shown to be an important determinant of rivalry onset, but, since removing such regions did not eliminate rivalry, other factors also have a role to play. The spatial frequency composition of the gratings is one such factor which is consistent with all of the findings we report.
Dynamic Representations of Human Body Movement
Authors: Kourtzi Zoe , Shiffrar Maggie
Published: November 2005

Psychophysical and neurophysiological studies suggest that human body motions can be readily recognized. Human bodies are highly articulated and can move in a nonrigid manner. As a result, we perceive highly dissimilar views of the human form in motion. How does the visual system integrate multiple views of a human body in motion so that we can perceive human movement as a continuous event? The results of a set of priming experiments suggest that motion can readily facilitate the linkage of different views of a moving human. Positive priming was found for novel views of a human body that fell within the path of human movement. However, no priming was observed for novel views outside the path of motion. Furthermore, priming was restricted to those views that satisfied the biomechanical constraints of human movement. These results suggest that visual representation of human movement may be based upon the movement limitations of the human body and may reflect a dynamic interaction of motion and object-recognition processes.
A mechanism underlying AMPA receptor trafficking during cerebellar long-term potentiation
Authors: Kakegawa Wataru , Yuzaki Michisuke
Published: November 2005

Long-term potentiation (LTP) is mediated by the activity-driven delivery of GluR1 glutamate receptors via Ca
2+
/calmodulin-dependent protein kinase II activity in various brain regions. Recently, postsynaptic LTP was shown to be induced at parallel fiber-Purkinje cell synapses by stimulating the parallel fibers at 1 Hz or applying a NO donor. Here, we demonstrate that NO-evoked postsynaptic LTP in mice cerebellum was blocked by botulinum toxin and enhanced by prior treatment with phorbol ester, which is known to induce GluR2 endocytosis. Interestingly, such LTP was not affected by a Ca
2+
/calmodulin-dependent protein kinase II inhibitor or a peptide binding to a protein interacting with C kinase 1, but was blocked by a peptide binding to
N
-ethylmaleimide-sensitive factor, which specifically binds to GluR2. Therefore, although the synaptic incorporation of GluR2 has been reported to be a constitutive pathway, NO-induced postsynaptic LTP in Purkinje cells is likely mediated by a pathway involving
N
-ethylmaleimide-sensitive factor-dependent GluR2 trafficking.
DNA assembly with gaps (Dawg): simulating sequence evolution
Authors: Cartwright Reed A.
Published: November 2005

Motivation: Relationships amongst taxa are inferred from biological data using phylogenetic methods and procedures. Very few known phylogenies exist against which to test the accuracy of our inferences. Therefore, in the absence of biological data, simulated data must be used to test the accuracy of methods which produce these inferences. Researchers have limited or non-existent options for simulations useful for studying the impact of insertions, deletions, and alignments on phylogenetic accuracy.

Results: To satisfy this gap I have developed a new algorithm of indel formation and incorporated it into a new, flexible, and portable application for sequence simulation. The application, called Dawg, simulates phylogenetic evolution of DNA sequences in continuous time using the robust general time reversible model with gamma and invariant rate heterogeneity and a novel length-dependent model of indel formation. On completion, Dawg produces the true alignment of the simulated sequences. Unlike other applications, Dawg allows indel lengths to be explicitly distributed via a biologically realistic power law. Many options are available to allow users to customize their simulations and results. Because simulating with indels would be problematic if biologically realistic parameters could not be estimated, a script is provided with Dawg that can estimate the parameters of indel formation from sequence data. Dawg was applied to the sequences of four chloroplast trnK introns. It was used to parametrically bootstrap an estimation of the rate of indel formation for the phylogeny. Because Dawg can assist in parametric bootstrapping of sequence data it is useful beyond phylogenetics, such as studying alignment algorithms or parameters of molecular evolution.

Availability: Dawg 1.0.0 can be obtained at the following websites: or . The package includes source code, example files, a brief manual and helper scripts. Binary distributions are available for Windows and Macintosh OS X. A development page for Dawg exists at , with links to a Subversion repository, mailing lists and updated versions.

Contact:  rac@uga.edu
A structure and evolution-guided Monte Carlo sequence selection strategy for multiple alignment-based analysis of proteins
Authors: Mihalek I. , Reš I. , Lichtarge O.
Published: November 2005

Motivation: Various multiple sequence alignment-based methods have been proposed to detect functional surfaces in proteins, such as active sites or protein interfaces. The effect that the choice of sequences has on the conclusions of such analysis has seldom been discussed. In particular, no method has been discussed in terms of its ability to optimize the sequence selection for the reliable detection of functional surfaces.

Results: Here we propose, for the case of proteins with known structure, a heuristic Metropolis Monte Carlo strategy to select sequences from a large set of homologues, in order to improve detection of functional surfaces. The quantity guiding the optimization is the clustering of residues which are under increased evolutionary pressure, according to the sample of sequences under consideration. We show that we can either improve the overlap of our prediction with known functional surfaces in comparison with the sequence similarity criteria of selection or match the quality of prediction obtained through more elaborate non-structure based-methods of sequence selection. For the purpose of demonstration we use a set of 50 homodimerizing enzymes which were co-crystallized with their substrates and cofactors.

Contact:  imihalek@bcm.tmc.edu

Supplementary information: Supplementary data are available at Bioinformatics online.
Pressure-induced polymorphism in cyclopropylamine
Authors: Lozano-Casal Patricia , Allan David R. , Parsons Simon
Published: November 2005

The crystal structure of cyclopropylamine at 1.2 GPa has been determined by X-ray diffraction methods. The structure of this phase is orthorhombic, space group Pbca and the unit-cell dimensions are a =  5.0741 (10), b  =  9.7594 (10) and c  =  13.305 (2) Å. Only one of the two H atoms of the amino group actively participates in the formation of the hydrogen-bonded chains, C(2) in graph-set notation, which lie parallel to the crystallographic a axis. Additionally, the topology of the crystal packing is studied using both Voronoi–Dirichlet polyhedra and Hirshfeld surface analyses for the low-temperature and the high-pressure structures of cyclopropylamine and the results are compared.
Incommensurately modulated ordering of tetrahedral chains in Ca2Fe2O5 at elevated temperatures
Authors: Krüger Hannes , Kahlenberg Volker
Published: November 2005

The basic building units of brownmillerite-type A
2
B
2O5 structures are perovskite-like layers of corner-sharing BO6 octahedra and zweier single chains of BO4 tetrahedra. A three-dimensional framework is formed by alternate stacking of octahedral layers and sheets of tetrahedral chains. The compound Ca2Fe2O5 is known to have Pnma symmetry at ambient conditions. The space group Imma was reported to be evident above 963 K. New high-temperature single-crystal X-ray diffraction experiments at 1100 K revealed that Ca2Fe2O5 forms an incommensurately modulated structure adopting the superspace group Imma(00γ)s00, with γ = 0.588 (2). The modulation affects the sequence of the enantiomorphic (right- and left-handed) oriented tetrahedral chains within the layer, breaking the lattice periodicity along c. This ordering can be modelled with crenel occupation modulation functions for the tetrahedrally coordinated Fe, as well as for the O atom interconnecting the tetrahedra.
Three modulation patterns in four related [M(H2O)2(15-crown-5)](NO3)2 structures
Authors: Hao Xiang , Parkin Sean , Brock Carolyn Pratt
Published: November 2005

The structures of [M(H2O)2(15-crown-5)](NO3)2, M = Cu, Zn, Mg and Co, and 15-crown-5 = 1,4,7,10,13-pentaoxacyclopentadecane, have been redetermined at 294 and 90 K. The four structures, and a second form of the Cu structure, have been reported in the literature, but are all incorrect in some significant way. The structures, which all have at least two independent formula units (i.e. Z′ ≥ 2), are related; each water ligand is hydrogen-bonded to two nitrate anions, while each nitrate anion is hydrogen bonded to the water ligands of two cations. In the tetragonal Co structure the hydrogen-bond pattern is three-dimensional; in the monoclinic Cu, Zn and Mg structures the hydrogen-bond patterns are two-dimensional. In the isostructural Zn and Mg structures Z′ = 3, while in the Cu structure Z′ = 5. The Cu, Zn and Mg structures are modulated variants of a basic structure, which was reported for Cu but which probably does not exist. The conformations of the 11 independent cations are remarkably similar; they all have approximate twofold symmetry and so exist as conformational enantiomers. The most important modulation is imperfect enantiomeric alternation of the cations along the longest cell axis; the independent cations are related by very good pseudotranslation and pseudoinversion operations. The diffraction patterns for all four structures have classes of weak, even very weak, reflections.
Isostructural phase transition in m-carboxyphenylammonium monohydrogenphosphite
Authors: Bendeif El-Eulmi , Dahaoui Slimane , François Michel , Benali-Cherif Nourredine , Lecomte Claude
Published: November 2005

Crystals of m-carboxyphenylammonium monohydrogenphosphite, C7H8NO_{2}^+·H2PO_3^{-} (m-CPAMP), space group P2_{1}/c, grown from aqueous solution undergo a reversible first-order single-crystal phase transition at Tc
= 246 (2) K with a hysteresis of 3.6 K. The thermal behaviour of the sample was characterized by differential scanning calorimetry (DSC) experiments. Variations of the unit-cell parameters versus temperature between 100 and 320 K are reported. The transition from the higher-temperature phase (HTP) to the lower-temperature phase (LTP) is characterized by a unit-cell volume contraction of 1.77%. The average structure and unit-cell packing of m-CPAMP at lower temperature (100 K) are reported from accurate X-ray data sets and compared with those of the higher-temperature phase (293 K) in order to investigate the mechanism of the phase transition. The reciprocal lattice reconstruction showed a few very weak satellite reflections which will be discussed in a forthcoming paper.
Second-degree twinning and dynamic disorder in the crystal structure of deca-dodecasil 3R
Authors: Langer Vratislav , Smrčok Ľubomír , Tunega Daniel , Wirnsberger Gernot
Published: November 2005

The structure of deca-dodecasil 3R (DD-3R), Si120O240, a very well suited material for the synthesis of inorganic/organic composites structured on a nanometer level, has been investigated in detail. So far, a highly complicated twinning has hampered its structure description at a desirable level of accuracy. This twinning has now been resolved and a new structure determination is presented. Structure refinement in the R\bar 3 space group revealed a large, unusually shaped atomic displacement ellipsoid for oxygen-bridging units (tetrahedra), bridging Si—O bonds shorter than expected and the linear Si—O—Si′ bond angle dictated by special positions at a threefold axis. A structure model based on a statistically disordered bridging O atom improved the accuracy of the Si—O bonds of interest, but provided unacceptable O—O contacts. To solve this dilemma, ab initio NVT molecular dynamics calculations were performed to study the possible configurations. Wavelet analysis of the time variations of selected Si—O distances pointed to a synchronous shift of the whole building units (tetrahedra). Low-frequency features of the calculated phonon density of states agree well with the published INS (inelastic neutron scattering) spectra of several silica polymorphs, indicating that the nature of the disorder in DD-3R is dynamic rather than static.