bluuebunny/crossref_metadata_2025 huggingface dataset:
Long‐term control of food intake and body weight by hydrodynamics‐based delivery of plasmid DNA encoding leptin or CNTF
Authors: Jiang Jingjing , Yamato Eiji , Miyazaki Jun‐ichi
Published: October 2003

Background

Obesity contributes to many common diseases, including cardiovascular and metabolic disorders such as diabetes, hypertension, and stroke. Leptin and ciliary neurotrophic factor (CNTF), two members of the cytokine family, play important roles in controlling food intake and body weight in rodents. Here, we used the hydrodynamics‐based gene delivery technique to introduce leptin and CNTF expression plasmids, pCAGGS‐leptin and pCAGGS‐CNTF, into mice and to assess whether they could induce high expression of leptin or CNTF and reduce food intake and body weight in the mice.

Methods

Plasmid DNA (50 µg) in lactated Ringer's solution (0.1 ml/g body weight) was rapidly injected into the tail vein of 4‐week‐old male MCH‐ICR mice.

Results

After a single injection, serum leptin peaked (at 32.0 ± 3.1 ng/ml) 2 days after the injection, and serum CNTF peaked (at 22.0 ± 0.8 µg/ml) 1 day after the injection. The high expression of either leptin or CNTF was sustained and dramatically reduced food intake (CNTF and leptin group vs. control group; 2.3 ± 0.5 and 3.1 ± 0.5 g/day vs. 4.8 ± 0.6 g/day; p < 0.001) and body weight (3 weeks after the injection; CNTF and leptin group vs. control group; −19.5% and +3.3% vs. +33.3–47.5%; p < 0.001) in the mice, suggesting potent in vivo activities for these exogenously expressed proteins.

Conclusions

These results suggest that hydrodynamics‐based gene delivery could have broad applications in the study of appetite regulation and metabolism. Copyright © 2003 John Wiley & Sons, Ltd.
Antisense oligodeoxynucleotide against HST‐1/FGF‐4 suppresses tumorigenicity of an orthotopic model for human germ cell tumor in nude mice
Authors: Hirai Kotaro , Sasaki Hideo , Sakamoto Hiromi , Takeshita Fumitaka , Asano Koji , Kubota Yoshinobu , Ochiya Takahiro , Terada Masaaki
Published: October 2003

Background

Overexpression of the fibroblast growth factor HST‐1/FGF‐4 gene is thought to mediate growth properties and malignancy in human testicular germ cell tumors. We have studied the effect that an antisense oligodeoxynucleotide against HST‐1/FGF‐4 suppresses tumorigenicity of a human germ cell tumor.

Methods and results

To test whether HST‐1/FGF‐4 could be the target of gene therapy for testicular carcinoma, 20‐mer phosphorothioate oligodeoxynucleotides (ODNs) directed against human HST‐1/FGF‐4 were analyzed for their antitumor activity. The antisense HST‐1/FGF‐4 ODNs suppressed HST‐1/FGF‐4 production by NEC8 human nonseminomatous germ cells and inhibited their cell growth in vitro. Furthermore, after orthotopic implantation of NEC8 cells, combined treatment with antisense HST‐1/FGF‐4 ODNs and Atelocollagen significantly inhibited the growth of testicular tumors as well as the incidence of lymph node metastasis. In contrast, administration of antisense ODNs alone was less effective.

Conclusions

Collectively, these results indicate that the antisense method against HST‐1/FGF‐4 gene expression will be a novel therapeutic approach for male germ cell tumors. The use of Atelocollagen‐mediated administration of the antisense HST‐1/FGF‐4 ODNs may be useful in enhancing the effects of antisense therapy. Copyright © 2003 John Wiley & Sons, Ltd.
Psychoanalysis and the Catholic Church in Italy: The role of Father Agostino Gemelli, 1925–1953
Authors: Colombo Daria
Published: October 2003

Agostino Gemelli, a Catholic priest, psychiatrist, administrator, and educator, was an important figure in
the early history of psychoanalysis in Italy. He was one of the few establishment figures to grapple with
Freud's ideas in Italy during the first half of the twentieth century, a period during which Italy,
compared to the rest of Europe and to the United States, was relatively impermeable to psychoanalysis. One of
the factors that contributed to this was the opposition of the powerful Catholic Church, which identified in
psychoanalysis a challenge to its authority. The author argues that Father Gemelli's shifting positions
about psychoanalysis between 1925 and 1953 reflected the exigencies of his historical circumstances. Gemelli was
able to identify in psychoanalysis an integrated view of the human condition in stark opposition to the brutal
reductionism of psychiatry in Italy at that time, but also encountered in it elements intolerable to the Church.
Examining specifically what it is that Gemelli could accept of psychoanalysis, and what needed to be rejected,
between 1925 and 1953, illustrates the particular challenge posed by psychoanalysis to Catholicism in Italy.
© 2003 Wiley Periodicals, Inc.
Metal dusting resistance of high chromium alloys
Authors: Grabke H. J. , Müller‐Lorenz E. M. , Martinz H. P.
Published: October 2003

Samples of 5 high Cr‐alloys were discontinuously exposed for 10,000 hours under severe metal dusting conditions, i. e. in flowing 49%CO‐49%H2‐2%H2O at 650°C. After each of the 11 exposure periods the mass change was determined and any coke removed and weighed. Metallographic cross sections were prepared after about 4,000 h and 10,000 h.

The high Cr‐alloys: 1. PM 2000 (Fe‐19%Cr‐5.5%Al‐0.5%Ti‐0.5%Y2O3), 2. Cr‐44%Fe‐5%Al‐0.4%Ti‐0.5%Y2O3, 3. Cr‐50%Ni, 4. Cr‐5%Fe‐1%Y2O3 and 5. porous chromium showed no or only minute metal dusting attack. Compared to the attack on reference samples of Alloy 601 (Ni‐23%Cr‐14%Fe‐1.4%Al), the metal dusting symptoms were negligible on the 5 high Cr‐alloys, minor coking and pitting and no internal carburization was observed. Because of the high Cr‐content, carbon solution and ingress should be minute, and in addition are inhibited by the formation of a chromia scale, as confirmed for four of the Cr‐rich alloys, and formation of an alumina scale on PM 2000. These alloys could be used for parts exposed to severe metal dusting conditions, and in fact, 50Cr‐50Ni has been applied successfully under such conditions.
Protective behaviour of newly developed coatings against metal dusting
Authors: Rosado C. , Schütze M.
Published: October 2003

Metal dusting is a corrosion phenomenon whose mechanisms and effects depend on different parameters such as temperature, pressure, time, material, etc. and which still leads to unexpected failure cases in several high temperature industries. The present work deals with the development and testing of coating systems against metal dusting attack and the evaluation of their protective behaviour at different temperatures. The recently developed coatings are based on high amounts of strong oxide formers, like Si, Ti, Cr and Al, which are able to form protective oxide layers even under the highly reducing metal dusting atmospheres. The coatings were applied on ferritic and austenitic steel substrates by HVOF and by (co) diffusion of one or up to three elements via a pack cementation process. The process parameters of the diffusion coatings were optimized with respect to the different substrate materials and diffusing species.

Isothermal tests at temperatures of 400°C, 620°C and 700°C under metal dusting atmospheres were carried out for up to 2022 h for coated and uncoated specimens. Discontinuous mass change measurements were performed in order to determine the kinetics of attack. After the corrosion tests metallographic cross sections of the specimens were investigated by optical and electron microscopy (SEM, EPMA). Especially the interdiffusion of substrate and coating and the formation of potentially protective oxide layers on top of the coatings were studied using elemental mapping and concentration profiles. The results obtained so far indicate that coatings have a high potential for significantly increasing the life‐time of components under metal dusting conditions. The different systems investigated are classified, evaluated, and discussed with respect to their protection potential and the responsible protection mechanisms.
Positive‐temperature‐coefficient/negative‐temperature‐coefficient effect of low‐density polyethylene filled with a mixture of carbon black and carbon fiber
Authors: Di Weihua , Zhang Guo , Xu Jianqing , Peng Yi , Wang Xiaojun , Xie Zhiyuan
Published: October 2003

Low‐density polyethylene (LDPE) filled with carbon black (CB) and carbon fiber (CF) composites were prepared by a conventional melt‐mixing method. The effects of a mixture of CB and CF on the positive‐temperature‐coefficient (PTC) effect and the negative‐temperature‐coefficient (NTC) effect, as well as the percolation threshold, were examined in detail. A synergy effect between CB and CF occurred, in that continuous conductive pathways formed within the CB/CF‐filled composite. The percolation threshold was moved to a reduced filler content with the addition of CF to an LDPE/CB composite. A model was proposed to explain the difference in the PTC behavior of composites containing CB and CF and composites containing only CB or CF. In addition, the NTC effect was weakened with a mixture of CB and CF, and a relatively small radiation dose was required to eliminate the NTC phenomenon in LDPE/CB/CF composites. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 3094–3101, 2003
Membrane osmometer for use at moderate applied pressures
Authors: Moses Corey L. , Rebelo Luis Paulo N. , Van Hook W. Alexander
Published: October 2003

A membrane osmometer designed for use at pressures greater than 0.1 MPa and less than 6 MPa was employed to determine the pressure coefficient of the equilibrium osmotic pressure (∂π/∂P) of a dilute polystyrene/toluene solution. The pressure coefficient of the second virial coefficient (∂A2/∂P), calculated from ∂π/∂P, was 6 (±4) × 10−5 cm3 mol g−2 MPa−1, which was in reasonable agreement with the value obtained from pressure‐dependent light scattering. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 3064–3069, 2003
Modelling discrete time survival data with random slopes: evaluating haemodialysis centres
Authors: Carvalho Marilia Sá , Knorr‐Held Leonhard
Published: October 2003

We propose a hierarchical discrete time survival model to analyse registry data on haemodialysis patients in Rio de Janeiro, Brazil, collected at different dialysis centres. Our aim is to estimate differences in hazard ratios attributable to variation in dialysis centre performance, after adjusting for further observed covariates both at the individual and centre level. The proposed model allowed for the estimation of a residual calendar time trend varying across dialysis centres through the adoption of a random slope model. These calendar time trends turned out to have significant variation, after adjustment for important observed covariates. The technique can be easily adapted to other diseases as long as survival time is the measurement of interest. Copyright © 2003 John Wiley & Sons, Ltd.
Proportion of treatment effect (PTE) explained by a surrogate marker
Authors: Chen Cong , Wang Hongwei , Snapinn Steven M.
Published: October 2003

In time‐varying covariate analysis of clinical survival data, it is often of interest to estimate the proportion of treatment effect (PTE), along with its confidence intervals, explained by a surrogate marker. The conventional procedure for such an analysis fits data into two working models separately to estimate the treatment effects before and after adjustment of the covariate. The construction of confidence intervals for the PTE under the conventional procedure lacks support by standard statistical software such as SAS, and could be very computationally demanding even after the support is available in the future. To overcome this problem, we propose a new procedure to simplify the computation. Under the new procedure, the treatment effects before and after adjustment of the covariate are simultaneously estimated from a single model. More important than saving computational effort, the new procedure can also be effectively applied to multiple‐covariate models for the decomposition of overall treatment effect and for the comparison of PTE among several surrogate markers. The new procedure is applied to the motivating data example from the LIFE study, and demonstrates flexibility that the conventional procedure currently lacks. Copyright © 2003 John Wiley & Sons, Ltd.
Editorial
Authors: COX GORDON , PITTS STEPHANIE
Published: October 2003

A common thread running through the articles in this issue is that enjoyment is a vital but somewhat elusive criterion in shaping effective and engaging experiences of music education. It becomes clear by reading these articles in conjunction that enjoyment is not always externally recognised as a necessary component of musical learning, but that it is highly valued by pupils and students of all ages, whether it is found in the teaching they receive or the music they make and listen to out of school.
Relationship between lidar‐based observations of aerosol content and monsoon precipitation over a tropical station, Pune, India
Authors: Devara P C S , Raj P E , Pandithurai G , Dani K K , Maheskumar R S
Published: October 2003

This paper reports the results of the aerosol lidar experiments that have been performed at the Indian Institute of Tropical Meteorology (IITM), Pune (18.54°N, 73.85°E, 559 m amsl), a tropical station in India. The lidar‐observed cloud macro‐physical parameters (cloud‐base and cloud‐ceiling heights, vertical thickness, etc.) and polarisation characteristics and their association with surface‐generated aerosols at the experimental site are presented and discussed. The correspondence among the lidar‐derived aerosol distributions, meteorological parameters and south‐west (SW) monsoon (June–September) activity over Pune during 12 successive SW monsoon seasons (1987–98) including two pairs of contrasting seasons of 1987–8 and 1993–4 is also examined. The results indicate an association between variations in aerosol loading in the boundary layer during the pre‐monsoon season (March–May) and precipitation intensity during the ensuing monsoon season. Moreover, the decrease in aerosol content from pre‐monsoon to monsoon season is found to follow the SW monsoon season total precipitation. Thus the results suggest that (i) the IITM lidar can also be a useful remote sensor for aerosol characterisation studies from polarisation measurements, and some important physical properties of clouds in the lower atmosphere over the station, and (ii) there exists a correspondence between boundary‐layer aerosol content and SW monsoon precipitation over Pune, which is explained in terms of the type of aerosols and the environmental and meteorological processes, particularly during pre‐monsoon and monsoon months prevailing over the experimental station. Copyright © 2003 Royal Meteorological Society
Building indicator groups based on species characteristics can improve conservation planning
Authors: Manne Lisa L. , Williams Paul H.
Published: October 2003

How well can indicator groups, as sets of species with well‐known distributions, represent the distribution of overall biodiversity to select networks of areas for conservation? In the literature, reliable indicator groups of complementarity have proven difficult to find, with some taxon‐based indicator groups resulting in no more species represented than when areas are chosen at random. We rigorously test which quantifiable characteristics of species make them better components of indicator groups of complementarity in area networks. We find that even indicator groups comprised of randomly chosen, taxonomically unrelated species perform better than randomly chosen areas, and we demonstrate the improved efficiency of protected‐area networks possible when using indicator groups chosen on the basis of species' characteristics.
Factors influencing the distribution, abundance and nest‐site selection of an endangered Egyptian vulture (Neophron percnopterus) population in Sicily
Authors: Sarà Maurizio , Di Vittorio Massimiliano
Published: October 2003

The Egyptian vulture (Neophron percnopterus) breeds in Sicily and, in 22 years of monitoring, has shown a decline followed by a slight recovery. We used Generalised Linear Models to predict: (1) the distribution range, (2) the habitat selection within the range, (3) the quality (i.e., occupation rate, breeding success) of breeding sites. Some 60% of Sicily proved to be unsuitable, being either too densely forested and without cliffs for nesting, or too densely populated, along with intensive agriculture. The models converged, indicating that the pairs select a precise upland habitat where low cliffs, distant from urban areas, are surrounded by arboreal crops and Mediterranean vegetation. The variables predicting the quality of a site are also related to human disturbance, including the distance from a road or the presence of heavy traffic. Natural restocking, in the last 3 years, is occurring in quiet sites and in proximity to extensive grazing land rich in sheep and goat herds. These results focused on short‐term programmes for local management of the species aimed at protracting the natural restocking: namely, the activation of (1) a stable system of artificial feeding stations, (2) nest site protection with joint activities for increasing public awareness, (3) a reintroduction project, by hacking, of juveniles born in captivity in Italian and European breeding centres.
Detection and accuracy rates of dogs trained to find scats of San Joaquin kit foxes (Vulpes macrotis mutica)
Authors: Smith Deborah A. , Ralls Katherine , Hurt Aimee , Adams Brice , Parker Megan , Davenport Barbara , Smith M. C. , Maldonado Jesus E.
Published: October 2003

Specially trained detection dogs have been used to locate faeces (scats) for faecal analyses but their effectiveness has not been quantified. We evaluated detection and accuracy rates of dogs trained to find scats of endangered San Joaquin kit foxes (Vulpes macrotis mutica). Four dogs found from 0.43 to 5.37 presumptive kit fox scats per km of transect searched in two field sites where kit foxes and coyotes (Canis latrans) but not non‐native red foxes (V. vulpes) were present. The unusually low detection rate (0.43 scats per km) by one dog (probably due to excessive panting in hot weather) was still similar to the average scat detection rate of two experienced humans. DNA tests of 1298 scats showed that all dogs were 100% accurate at distinguishing kit fox scats under our field conditions. Because red foxes are sympatric with kit foxes in some areas, we also conducted controlled discrimination experiments to see if trained dogs could distinguish between scats from kit and red foxes. Four dogs were 100% accurate at choosing a kit fox scat when red fox scats were present (n= 64 trials), but were less accurate at ignoring red fox scats in trials where a kit fox scat was absent.
Reactive nitrogen in Asian continental outflow over the western Pacific: Results from the NASA Transport and Chemical Evolution over the Pacific (TRACE‐P) airborne mission
Authors: Talbot R. , Dibb J. , Scheuer E. , Seid G. , Russo R. , Sandholm S. , Tan D. , Singh H. , Blake D. , Blake N. , Atlas E. , Sachse G. , Jordan C. , Avery M.
Published: October 2003

We present here results for reactive nitrogen species measured aboard the NASA DC‐8 aircraft during the Transport and Chemical Evolution over the Pacific (TRACE‐P) mission. The large‐scale distributions total reactive nitrogen (NOy,sum = NO + NO2 + HNO3 + PAN + C1–C5 alkyl nitrates) and O3 and CO were better defined in the boundary layer with significant degradation of the relationships as altitude increased. Typically, NOy,sum was enhanced over background levels of ∼260 pptv by 20‐to‐30‐fold. The ratio C2H2/CO had values of 1–4 at altitudes up to 10 km and as far eastward as 150°E, implying significant vertical mixing of air parcels followed by rapid advection across the Pacific. Analysis air parcels originating from five principal Asian source regions showed that HNO3 and PAN dominated NOy,sum. Correlations of NOy,sum with C2Cl4 (urban tracer) were not well defined in any of the source regions, and they were only slightly better with CH3Cl (biomass tracer). Air parcels over the western Pacific contained a complex mixture of emission sources that are not easily resolvable as shown by analysis of the Shanghai mega‐city plume. It contained an intricate mixture of pollution emissions and exhibited the highest mixing ratios of NOy,sum species observed during TRACE‐P. Comparison of tropospheric chemistry between the earlier PEM‐West B mission and the recent TRACE‐P data showed that in the boundary layer significant increases in the mixing ratios of NOy,sum species have occurred, but the middle and upper troposphere seems to have been affected minimally by increasing emissions on the Asian continent over the last 7 years.
A fast‐GC/MS system to measure C2 to C4 carbonyls and methanol aboard aircraft
Authors: Apel E. C. , Hills A. J. , Lueb R. , Zindel S. , Eisele S. , Riemer D. D.
Published: October 2003

A fast response gas chromatograph/mass spectrometer (FGCMS) instrument to measure ≤C2 through C4 carbonyl compounds and methanol was developed for the NASA Global Tropospheric Experiment (GTE) Transport and Chemical Evolution over the Pacific (TRACE‐P) mission. The system consists of four major components: sample inlet, preconcentration system, gas chromatograph (GC), and detector. The preconcentration system is a custom‐built cryogen‐conservative system. The GC is a compact, custom‐built unit that can be temperature programmed and rapidly cooled. Detection is accomplished with an Agilent Technologies 5973 mass spectrometer. The FGCMS instrument provides positive identification because the compounds are chromatographically separated and mass selected. During TRACE‐P, a sample was analyzed every 5 min. The FGCMS limit of detection was between 5 and 75 pptv, depending on the compound. The entire instrument package is contained in a standard NASA instrument rack (106 cm × 61 cm × 135 cm), consumes less than 1200 watts and is fully automated with LabVIEW™ 6i. Methods were developed for producing highly accurate gas phase standards for the target compounds and for testing the system in the presence of potential interferents. This paper presents data on these tests and on the general overall performance of the system in the laboratory and aboard the DC‐8 aircraft during the mission. Vertical profiles for acetaldehyde, methanol, acetone, propanal, methyl ethyl ketone, and butanal from FGCMS data collected over the entire mission are also presented.
Electronic absorption spectra of B3 and B3− in neon matrices and ab initio analysis of the vibronic structure
Authors: Wyss Muriel , Riaplov Evgueni , Batalov Anton , Maier John P. , Weber Thomas , Meyer Wilfried , Rosmus Pavel
Published: October 2003

Mass selected B3− ions have been isolated in 6 K neon matrices and their absorption spectra measured. A band system with origin at 467 nm is assigned as the E′1←X 1A1′ electronic transition of the cyclic anion. After photobleaching, the 1 2E′←X 2A1′ and 2 2E′←X 2A1′ band systems of neutral cyclic B3 are observed which start around 736 and 458 nm, respectively. Large scale ab initio calculations have provided potential energy surfaces for a variational treatment of the vibrational motion. Calculated band origins leave no doubt about the electronic symmetry assignments. The complex vibrational structure in the 1 2E′ state, which is due to relatively strong Jahn–Teller distortions, appears to be closely reproduced by the calculated vibrational energies and intensities, if the first observed stronger line is identified with the first vibrationally excited state, placing the “true” band origin of the 1 2E′ state at 775 nm where no signal with significant strength is apparent. The 2 2E′ state undergoes only a relatively weak Jahn–Teller distortion and shows a short progression with an observed frequency of 981(10) cm−1 that compares favorably with the theoretical frequency of 973 cm−1. The E′1 system of B3− shows a Jahn–Teller activity comparable to that of the 1 2E′ state of B3.
Theory of solutions in the energy representation. III. Treatment of the molecular flexibility
Authors: Matubayasi Nobuyuki , Nakahara Masaru
Published: October 2003

The method of energy representation for evaluating the solvation free energy is extended to a solute molecule with structural flexibility. When the intramolecular structure of the solute molecule exhibits a strong response to the solute–solvent interaction, the approximate functional for the solvation free energy needs to be modified from the original form presented previously [J. Chem. Phys. 117, 3605 (2002); 118, 2446 (2003)]. In the modification of the functional, the solvation-induced change in the distribution function of the solute structure is taken into account with respect to the intramolecular energy of the solute. It is then demonstrated over a wide range of thermodynamic conditions that the modified form of functional provides an accurate and efficient route to the solvation free energy of a flexible solute molecule even when the structural distribution function of the solute in solution overlaps barely with that of the solute at isolation.
Extended ab initio quantum mechanical/molecular mechanical molecular dynamics simulations of hydrated Cu2+
Authors: Schwenk Christian F. , Rode Bernd M.
Published: October 2003

Copper(II) was used as a model system to investigate the relevance of including the full second hydration shell in ab initio treatment while describing hydrated ions in hybrid quantum mechanical/molecular mechanical molecular dynamics (QM/MM MD) simulations. Three different simulation techniques were applied (Hartree–Fock, B3LYP, and resolution of the identity density functional theory) to find a good compromise between accuracy and simulation speed. To discuss details of the hydration structure radial distribution functions, coordination number distributions and various angular distributions have been used. Dynamical properties such as vibrational motions of water molecules and ion–oxygen stretching motions were investigated using approximative normal coordinate analyses. QM/MM MD simulations offer a detailed time picture of the dynamic Jahn–Teller effect of Cu2+ showing short-term as well as long-term distortions to occur within <200 fs and 2–3 ps. The results prove that for transition metal ions such as Cu2+ the inclusion of the second shell into the ab initio treated region can be of decisive importance for obtaining accurate results and that such simulations can offer new insights into chemical dynamics on the picosecond scale.
Mobile sample holder applying multiple heating systems with a variable heating and cooling rate
Authors: Leist U. , Winkler A. , Büssow J. , Al-Shamery K.
Published: October 2003

A mobile sample holder applying multiple heating systems with variable heating and cooling opportunities will be presented. Design details and initial results will be given. The whole sample holder system consists of two units: the docking station (one) on which the mobile sample holder together with its mobile sample plate (two) is mounted. Some of the significant advantages of this system in comparison with others are as follows. The docking station can be attached to the cold face of continuous flow cryostats or reservoir cryostats thus enabling cooling via, e.g., liquid nitrogen. The modular design of the sample holder allows it to be individually customized to fulfill specifically required heating methods (e.g., resistance heating, electron bombardment heating, direct heating, conductivity heating) for different sample materials (insulators, semiconductors, conductors). Furthermore, the variable setup allows for optimization with respect to cooling or heating properties as well as the incorporation of samples with different sizes and shapes. Even commercially available sample carrier systems can be combined with this sample holder design and still retain all heating and cooling features.
Stress- and strain-controlled measurements of interfacial shear viscosity and viscoelasticity at liquid/liquid and gas/liquid interfaces
Authors: Erni Philipp , Fischer Peter , Windhab Erich J. , Kusnezov Victor , Stettin Heiko , Läuger Jörg
Published: October 2003

An interfacial rheometer for both stress- and strain-controlled measurements of shear rheological properties at liquid/liquid and gas/liquid interfaces is presented. The device is based on a rotating or oscillating biconical bob design in combination with a low friction electronically commutated motor system. The interfacial shear stress, viscosity, and dynamic moduli are obtained by solving the Stokes equations (low Reynolds number) along with the Boussinesq–Scriven interfacial stress tensor, which is used for the boundary conditions at the interface. An improved and simple numerical method for the calculation of the velocity distribution in the measuring cell is presented. The scope and limitations of the rheometer are discussed. Results from steady shear and oscillatory experiments as well as creep recovery and stress relaxation tests at both oil/water and air/water interfaces with adsorbed films of a globular protein (ovalbumin) and spread films of a surfactant (sorbitan tristearate) are presented.
Recent progress in bidirectional interrogation techniques for enhancing multiplexing capability of fiber optic white light interferometric sensors
Authors: Yuan Libo , Zhou Limin , Jin Wei
Published: October 2003

In smart structure applications where fiber sensors are embedded within structural materials, multiple lead in/out fibers are preferred for redundancy and improving reliability. The use of only one lead/out fiber is not optimal because the breakage of a fiber at one location due to, for example, local structural damage, would cause the failure of the whole sensing system. The multiplexing and networking techniques suitable for such applications have attracted considerable research recently. In this article, based on the bidirectional interrogation technique for white light interferometric sensors arrays, a multiplexed fiber optic deformation sensor loop network suitable for smart structure applications has been designed and demonstrated. Loop-network sensor systems are based on the white light interferometric technique. Michelson and Mach–Zehnder optical path interrogators have been developed and demonstrated, respectively. For the usually used one direction interrogate sensing system, it is clear that multiplexed sensor arrays suffer from relatively large fiber segment-induced optical reflective and excess insertion loss that generally limit the total number of sensors that can be accommodated in this configuration. This loop-network bidirection interrogating technique greatly extended the multiplexing capacity of fiber optic white light interferometric sensors system. A practical implementation of this technique is presented which makes use of a popular light emitting diode, superluminescent diode, or amplified spontaneous emission optical light source and standard single mode fiber, which are commonly used in the communication industry. The sensor loop topology is completely passive and absolute length measurements can be obtained for each sensing fiber segment so that it can be used to measure quasidistribution strain or temperature. For large-scale smart structures, this technique not only extends the multiplexing potential, but also provides a redundancy for the sensing system. It means that the sensor loop permits one point breakdown, because the sensing system will still work whenever the embedded sensor loop breaks somewhere.
Spectroscopic characterization of the first singlet (Ã B11) excited state of Li167O7Li
Authors: Bellert D. , Winn D. K. , Breckenridge W. H.
Published: October 2003

Using laser induced fluorescence (LIF) and resonance enhanced two-photon ionization (R2PI) spectroscopy, several (ν1′,ν2′,ν3′) vibrational bands of the Ã 1B1(K′=1)←X̃ 1Σg+(0,0,0) perpendicular transition of the Li167O7Li molecule have been rotationally resolved and analyzed to yield effective A′,B′,C′ values. The estimated geometry of the Ã 1B1 state does not vary with ν1′ (symmetric stretch mode), but θ′ increases and R′ decreases slightly as ν2′ (bending mode) increases. Extrapolation leads to an estimate for the (0,0,0) state of θ0′=105±5°, R0′=1.86±0.04 Å, and for the potential minimum θe′=102±5°, Re′=1.87±0.04 Å. The strongly bent nature of the Ã 1B1 state is due to promotion of an O−2 p-electron (b1) from the strongly ionic, linear Li+O−2Li+ ground state to an a1 molecular orbital which has Li/Li bonding character. The Ã 1B1 state thus has an approximately Li+1/2O−1Li+1/2 charge distribution, so that the ionic bonding is less strong than in the linear ground state, where (from this study and an earlier stimulation-emission pumping study) R0″=1.611±0.003 Å. In fact, the Li–Li distance in the Ã 1B1 state, ∼3.0 Å, is quite similar to that of the Li2+1 ion, so the bonding may be described as that of Li2+1 bound ionically to the O−1 ion.
A source of error in the velocity measurement of large spherical bubbles using laser Doppler anemometry
Authors: Rivière Nicolas , Cartellier Alain , Lemaı̂tre-Auger Pierre
Published: October 2003

This article reports a source of error in the velocity measurements of large spherical bubbles by laser Doppler anemometry. Experimental evidences gathered in Poiseuille bubbly flows, as well as on controlled bubble streets, show that, for a detector at a 90° viewing angle, the velocity of millimeter size spherical bubbles can be underestimated by 15%. Such a bias is shown to arise from the interaction on the receiver of two optical contributions, one from external reflection and one from internal reflection, produced from the same bubble. Their combination leads to alterations of the Doppler frequency inside a burst, and hence, to improper velocity measurements. An analysis based on geometrical optics indicates that such a combination is possible only for a ratio of the probe volume to the bubble diameter larger than unity. Such a conclusion is supported by careful experiments. Finally, simple ways of avoiding this bias are proposed and validated.
An acoustic position sensor
Authors: Dong Shuxiang , Bai Feiming , Li Jie-Fang , Viehland Dwight
Published: October 2003

This article presents an acoustic method—the resonance acoustic field sensor or piezoelectric-sound-resonance cavity (PSRC)—for object position detection. This method utilizes the change of acoustic radiation impedance as a sensing mechanism. The PSRC both generates and detects a resonance acoustic field, along both the axial and transverse directions. We have discovered that an inserted object or an object motion in the sound radiation field results in changes in both the voltage and phase of the PSRC. Results have shown that a minimum object displacement of <10 μm can be detected in the axial direction (and <100 μm in the transverse) by this method.
A high-current pulsed cathodic vacuum arc plasma source
Authors: Oates T. W. H. , Pigott J. , Mckenzie D. R. , Bilek M. M. M.
Published: October 2003

Cathodic vacuum arcs (CVAs) are well established as a method for producing metal plasmas for thin film deposition and as a source of metal ions. Fundamental differences exist between direct current (dc) and pulsed CVAs. We present here results of our investigations into the design and construction of a high-current center-triggered pulsed CVA. Power supply design based on electrolytic capacitors is discussed and optimized based on obtaining the most effective utilization of the cathode material. Anode configuration is also discussed with respect to the optimization of the electron collection capability. Type I and II cathode spots are observed and discussed with respect to cathode surface contamination. An unfiltered deposition rate of 1.7 nm per pulse, at a distance of 100 mm from the source, has been demonstrated. Instantaneous plasma densities in excess of 1×1019 m−3 are observed after magnetic filtering. Time averaged densities an order of magnitude greater than common dc arc densities have been demonstrated, limited by pulse repetition rate and filter efficiency.
The “La Vue-des-Alpes” underground laboratory
Authors: Gonin Yvan , Busto José , Vuilleumier Jean-Luc
Published: October 2003

The measurement of the intrinsic radioactivity in a wide range of solid, liquid, and gaseous materials is very important for several activity domains, such as in particle physics experiments, medical research, environmental activity, and natural resources. Very precise measurements can be undertaken in the “La Vue-des-Alpes” Underground Laboratory. This article describes this laboratory and the measurements we have performed there.
Heterodyne interferometric technique for displacement control at the nanometric scale
Authors: Topcu Suat , Chassagne Luc , Haddad Darine , Alayli Yasser , Juncar Patrick
Published: October 2003

We propose a method of displacement control that addresses the measurement requirements of the nanotechnology community and provide a traceability to the definition of the mèter at the nanometric scale. The method is based on the use of both a heterodyne Michelson’s interferometer and a homemade high frequency electronic circuit. The system so established allows us to control the displacement of a translation stage with a known step of 4.945 nm. Intrinsic relative uncertainty on the step value is 1.6×10−9. Controls of the period of repetition of these steps with a high-stability quartz oscillator permits to impose an uniform speed to the translation stage with the same accuracy. This property will be used for the watt balance project of the Bureau National de Métrologie of France.
Simplified system based on photoelastic modulation technique for low-level birefringence measurement
Authors: Peng H. J. , Wong S. P. , Lai Y. W. , Liu X. H. , Ho H. P. , Zhao Shounan
Published: October 2003

In this article, the authors present a new low-level birefringence detection (LLBD) system based on the use of a photoelastic modulator. This system uses a single modulator so that only one detector is required to capture all the frequency components in the optical beam. The design removes gain errors associated with the conventional dual-beam approach. In addition, we also incorporate a complete analytical signal-processing algorithm to enhance measurement accuracy by eliminating the requirement of small phase angle approximation. To demonstrate the operation of our LLBD system, we performed birefringence measurement on a silicon wafer to characterize the distribution of its internal stress. Results obtained from our experiments indicate that the instrument has high sensitivity and good repeatability. The birefringence measurement sensitivity of our system was found to be about 0.03° (or 0.096 nm at 1152 nm). Several samples with different levels of birefringence were studied using our LLBD system.
Fiber-loop ring-down spectroscopy: A sensitive absorption technique for small liquid samples
Authors: Tong Zhaoguo , Jakubinek Michael , Wright Alexander , Gillies Alison , Loock Hans-Peter
Published: October 2003

Cavity ring-down spectroscopy has proven to be a very sensitive gas-phase spectroscopic technique, suitable to record either very weak transitions of abundant gases or stronger transitions of trace gases. Here, an adaptation of the ring-down measurement principle to optical waveguides is presented. Fiber-loop ring-down spectroscopy (FLRDS) allows for the measurement of absorption spectra of minute quantities of liquid solutions. An optical fiber is wound into a loop using a fiber splice connector. A nanosecond laser light pulse (λ∼810 nm) is coupled into the loop and the light pulses are detected using a photomultiplier detector. It is found that once the light is coupled into the fiber it experiences very little loss and the light pulses do a large number of round trips before their intensity is below the detection threshold. The characteristic ring-down time is obtained by exponential fitting of the envelope of the wave form. This method is well suited to characterize low-loss processes in fiber optic transmission independent from power fluctuations of the light source. The strengths of the technique are demonstrated by characterization of a variety of loss processes—in particular by the measurement of the absolute loss of the optical fiber and of the fiber connector, losses due to macrobending of a section of the fiber loop, as well as losses due to lateral and longitudinal displacement in the fiber–fiber connection. Furthermore, it is shown that FLRDS is useful as an absorption spectroscopic technique for very small sample volumes and may be applied as an absorption detection method in analytical chemistry devices. A crude 47 μm channel in polydimethylsiloxane polymer was fabricated between the fiber end facets and the dye 1,1′-diethyl-4,4′-dicarbocyanine iodide (DDCI) was introduced into the channel. From the concentration dependence of ring-down time the sample volume was determined as 700 pL and the detection limit as about 10−10 mol, or 7×10−8 g of DDCI.
Time-resolving and energy-dispersive photoelectron detector for combined laser and synchrotron radiation experiments
Authors: Gießel T. , Bröcker D. , Schmidt P. , Widdra W.
Published: October 2003

A time-resolving and energy-dispersive photoelectron detector for time-resolved experiments has been set up for pump–multiple-probe experiments with combined laser and synchrotron radiation. The time resolution of the detector of about 1 ns allows an assignment of the photoelectron signal to a specific synchrotron radiation pulse for any filling pattern of third-generation synchrotron storage rings. This leads to an overall temporal resolution given by the synchrotron radiation pulse width, which is 30 ps at the synchrotron radiation facility BESSY, Berlin. Application of the pump–multiple-probe technique is demonstrated for time-resolved photoemission experiments with combined laser and synchrotron radiation.
A viscosity and density meter with a magnetically suspended rotor
Authors: Bánó Mikuláš , Strhársky Igor , Hrmo Igor
Published: October 2003

A device for measuring the viscosity and density of liquids is presented. It is a Couette-type viscometer that uses a submerged rotor to measure the viscosity without errors originating in the contact of the rotor with the sample/air boundary. The inner cylinder is a glass rotor suspended in the liquid, and the outer cylinder is also made of glass. The rotor is stabilized on the axis of the outer cylinder by an electromagnetic force controlled by feedback from the rotor’s vertical position. In the lower part of the rotor is an aluminum cylinder located in a magnetic field generated by rotating permanent magnets. The interaction of this rotating magnetic field with eddy currents generated in the aluminum cylinder causes rotation of the rotor. This rotation is optically detected, and viscosity is calculated from the measured angular velocity of rotor. The density of the liquid is calculated from the applied vertical equilibrating force. A computer controls the whole measurement. The device works at constant temperature or while scanning temperature. The sample volume is 1.6 ml, and the accuracy of measurement of both viscosity and density is ∼0.1%. The range of measured densities is (0.7–1.4) g/ml, and viscosity can be measured in the range (3×10−4–0.3) Pa s. The shear rate of the viscosity measurement varies in the range (20–300) s−1. The accuracy of the temperature measurement is 0.02 K.
Boundary element methods for dielectric cavity construction and integration
Authors: Chen Feiwu , Chipman Daniel M.
Published: October 2003

Improvements in boundary element methods are described for solution of reaction field equations that incorporate important dielectric effects of solvation, including influences of volume polarization, into electronic structure calculations on solute properties. Most current implementations assume constant boundary elements on the cavity surface separating solvent from solute, often employing an empirical parameter to enhance slow convergence associated with the treatment of singularities. In this work we describe a scheme for the linear interpolation of boundary elements and the analytic treatment of singularities that improves convergence without the need for any empirical parameter. Another advance is described for isodensity surface triangulation that succeeds even with molecular surfaces having prominent pockets, which cause the failure of previous simpler methods. Numerical examples are presented to demonstrate the efficacy of these new procedures in practice.
A density functional view of transition state theory: Simulating the rates at which Si adatoms hop on a silicon surface
Authors: Somasi Sweta , Khomami Bamin , Lovett Ronald
Published: October 2003

Density functional theory is used to give an operational definition for the “free energy surface” on which Si adatoms move over a (100) silicon surface. Molecular dynamics simulations using the empirical Stillinger–Weber potential are used to numerically evaluate free energy surfaces near binding sites and along the important hopping paths. Transition state theory is used to deduce hopping rates at T≈500  and 1000 K from these free energy surfaces for the basic steps responsible for “surface diffusion.” The difference in the activation free energies at these temperatures and the T=0 barrier heights is emphasized.
Statistical evaporation of rotating clusters. II. Angular momentum distribution
Authors: Parneix P. , Calvo F.
Published: October 2003

The change in the angular momentum of an atomic cluster following evaporation is investigated using rigorous phase space theory (PST) and molecular dynamics simulations, with an aim at the possible rotational cooling and heating effects. Influences of the shape of the interaction potential, anharmonicity of the vibrational density of states (DOS), and the initial distribution of excitation energies are systematically studied in the example of the Lennard-Jones cluster LJ14. For this system, the predictions of PST are in quantitative agreement with the results of the simulations, provided the correct forms for the vibrational density of states and the interaction potential are used. The harmonic approximation to the DOS is used to obtain explicit forms for the angular momentum distribution in larger clusters. These are seen to undergo preferential cooling when thermally excited and preferential heating when subject to a strong vibrational excitation.
Velocity map imaging of the photodissociation of CF3I+ in the Ã←X̃ band
Authors: Aguirre F. , Pratt S. T.
Published: October 2003

The photodissociation dynamics of CF3I+ has been investigated within the Ã←X̃ band by means of velocity map ion imaging. The CF3I+ cation is prepared by resonance-enhanced multiphoton ionization of CF3I via the [X̃ 2E3/2]6p, [2]501 band, and the (X̃ 2E3/2) ground-state population in the CF3I+ ion is unambiguously characterized by using photoelectron spectroscopy. Photodissociation of the state-selected CF3I+ ion results in fragmentation to both CF3++I and CF3+I+. The translational energy distribution derived from the two-dimensional images of the CF3+ fragments shows vibrational progressions that provide detailed information on the channeling of the parent internal energy into the dissociation process. The translational energy distribution of the CF3+ fragment shows a one-to-one dependence on the excitation energy, which is typical of a single-photon dissociation process. The observation of a repeated pattern of rings in the CF3+ images with an interval of ∼800 cm−1 indicates that the ν2 umbrella mode of the CF3+ fragment is excited upon dissociation. The low-kinetic-energy release observed in this channel indicates that substantial energy is deposited into the internal degrees of freedom of the CF3+ fragment and suggests that the dissociation is controlled by the Franck–Condon factors between the parent ion and fragments. The translational energy distribution of the I+ fragment is independent of the excitation wavelength and includes a feature peaking at near-zero kinetic energy. Plausible mechanisms for the CF3+ and I+ dissociation channels are discussed in terms of the observed kinetic energy and anisotropy distributions derived from the two-dimensional ion images.