bluuebunny/crossref_metadata_2025 huggingface dataset:
Degradation of human aquaporin 0 by m‐calpain
Authors: Ma H. , Azuma M. , Shearer T.R.
Published: November 2005

Opacities (cataracts) in the lens of the eye are a leading cause of preventable blindness. Aquaporins function as water channels, and the C‐terminus is postulated as a regulatory domain. The C‐terminal domain of aquaporin 0 (AQP0) develops numerous truncation sites during lens aging. The purpose of the present experiment was to determine if the calcium‐activated protease m‐calpain (EC 3.4.22.17) was responsible for truncation of human AQP0. AQP0 was isolated from young human donors, incubated with recombinant m‐calpain, and the cleavage sites on the released peptides were determined by on‐line electrospray ionization mass spectrometry. We found that four cleavage sites on human AQP0 could be tentatively assigned to m‐calpain. This is the first evidence for possible calpain activity in human lens. Because the cause(s) of 17 other cleavage sites was unknown, the data also suggested that other, as yet unknown, proteases or non‐enzymatic mechanisms are more active than calpain in human lens.
Conventional and color Doppler sonography in preoperative assessment of ovarian tumors
Authors: Tempe A. , Singh S. , Wadhwa L. , Garg A.
Published: November 2005

Objective: To study the vascular patterns of ovarian tumors by color Doppler imaging (CDI) and compare the findings of conventional sonographic studies and CDI with histopathologic findings for the same tumors. Methods: Fifty nonpregnant women scheduled for elective surgery for ovarian tumors were examined by sonographic scanning and CDI by the same physician. Sonographic morphology scores [SMSs] were used, and the pulsatility index (PI) and resistance index (RI) were calculated after locating vessels in and around the tumors by CDI. Results: It was possible to obtain CDI results in 26 of the 50 women. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were 100%, 71.43%, 73.33%, and 100%, respectively, for SMS. With CDI, the sensitivity, specificity, PPV, and NPV were 100%, 85.72%, 95%, and 100% for PI and 100%, 71.43%, 90.48%, and 100% for RI. RI sensitivity and specificity were identical to those of SMS, i.e., 100% and 71.43%, respectively, but PI specificity was better (85.72%). Conclusion: In this study, CDI was definitely better than SMS when color flow could be obtained through the tumors. The overall efficiency in diagnosing the nature of tumors is very high if SMS and CDI are both used in patients having ovarian tumors.
Self-Help: Towards the Next Generation
Authors: Richardson Rachel , Richards David A.
Published: November 2005

In the UK, recent guidelines on the treatment of depression and anxiety recommend CBT-based self-help materials as one important component of services. However, despite being based on specific CBT techniques or “empirically grounded interventions”, early optimism has been dented by data from recent studies that have cast doubt on the effectiveness of the current generation of these materials. As a consequence, it may be necessary to consider that other factors may contribute to the overall magnitude of CBT effects. Indeed, it is logically inconsistent to argue that specific factors are pre-eminent in CBT whilst maintaining that delivery via therapists is more likely to be effective than self-help. The contribution of “common factors” that operate in personal therapeutic encounters, for example, therapist responsiveness and the patient-therapist alliance, may be one possible overlooked reason for the reduced ef-fectiveness of self-help materials. The development of the next generation of self-help materials, therefore, may benefit from the testing of materials that combine common and specific factors, including specific measurement of the strength of common factors and their relationship to clinical outcomes. We discuss a model of such common factors and suggest how they could be incorporated into the next generation of CBT based self-help materials.
Cognitive Behavioural Therapy and Homelessness: A Case Series Pilot Study
Authors: Maguire Nick
Published: November 2005

This paper describes a project set up to treat four homeless men using cognitive behavioural therapy (CBT). The referral criteria were that individuals had alcohol and/or substance misuse problems, were roofless (i.e. sleeping rough) immediately before the intervention began and found it difficult or impossible to access hostel places in Southampton. Excessive alcohol use, violence (against self, others and property) and prison sentences were all features of their presentation. The project involved three levels of CBT intervention provided by the clinical psychologist: 1) training for the staff to enable them to work within this model; 2) continued supervision within model to ensure consistency and sustainability; 3) individual formulation (description of the problem within the CBT framework) and psychotherapy. The house itself was also run on a collaborative basis. A number of measures including mental health and social functioning constructs were used to evaluate the project, in addition to some qualitative data. All residents reduced incidents of theft, violence and alcohol consumption. Risk to self and others was also reduced for all residents. Perceived self-efficacy increased slightly for all residents, and staff perceived that they could be more effective, less hopeless, and therefore possibly less stressed as a result of training. More data will be gathered over time.
Patient Treatment Adherence in Cognitive Behaviour Therapy for Acute Psychosis: The Role of Recovery Style and Working Alliance
Authors: Startup Mike , Wilding Noeline , Startup Sue
Published: November 2005

Treatment non-adherence is a common problem in mental health services but little is known about non-adherence to psychological therapy for psychosis. The main aim of the present study was to investigate the role of patients' recovery style and the therapeutic alliance in provoking or forestalling patient drop-out from cognitive behaviour therapy (CBT) for psychosis. Ratings were made by two independent observers on 29 recordings of sessions from a controlled trial of CBT for psychosis. Sessions of 10 patients who dropped out of treatment prematurely were matched with sessions of 10 patients who stayed in. Another nine sessions were selected at random from the middle and late stages of treatment so that the sample was representative of all sessions in the trial. Patients who dropped out of treatment, compared with those who stayed in, were less engaged in treatment, showed less agreement with their therapists, and had a sealing-over recovery style before they dropped out but did not differ in their therapeutic bonds. The results suggest that the premature termination of the drop-outs was not provoked by the therapists but was due to the patients' lack of curiosity about their psychotic episodes and minimization of the impact of their illness.
Implications of the activational cleavage of PAR1 by MMP-1 in human breast cancer
Authors: Mercuri Francesca A. , Thompson Erik W.
Published: November 2005

Citation of original article:

A. Boire, L. Covic, A. Agarwal, S. Jacques, S. Sherifi, A. Kuliopulos. PAR1 is a matrix metalloprotease-1 receptor that promotes invasion and tumorigenesis of breast cancer cells.Cell2005;120(3): 303–13.

Abstract of the original article

Protease-activated receptors (PARs) are a unique class of G protein-coupled receptors that play critical roles in thrombosis, inflammation, and vascular biology. PAR1 is proposed to be involved in the invasive and metastatic processes of various cancers. However, the protease responsible for activating the proinvasive functions of PAR1 remains to be identified. Here, we show that expression of PAR1 is both required and sufficient to promote growth and invasion of breast carcinoma cells in a xenograft model. Further, we show that the matrix metalloprotease, MMP-1, functions as a protease agonist of PAR1 cleaving the receptor at the proper site to generate PAR1-dependent Ca2+signals and migration. MMP-1 activity is derived from fibroblasts and is absent from the breast cancer cells. These results demonstrate that MMP-1 in the stromal-tumor microenvironment can alter the behavior of cancer cells through PAR1 to promote cell migration and invasion.
Review of: Are breast density and bone mineral density independent risk factors for breast cancer?
Authors: Hopper J. L.
Published: November 2005

Citation of original article:

K. Kerlikowske, J. Shepherd, J. Creasman, J. A. Tice, E. Ziv, S. R. Cummings. Are breast density and bone mineral density independent risk factors for breast cancer. Journal of the National Cancer Institute 2005; 97(7): 368–74.

Abstract of the original article

Background: Mammographic breast density and bone mineral density (BMD) are markers of cumulative exposure to estrogen. Previous studies have suggested that women with high mammographic breast density or high BMD are at increased risk of breast cancer. We determined whether mammographic breast density and BMD of the hip and spine are correlated and independently associated with breast cancer risk. Methods: We conducted a cross-sectional study (N = 15 254) and a nested case-control study (of 208 women with breast cancer and 436 control subjects) among women aged 28 years or older who had a screening mammography examination and hip BMD measurement within 2 years. Breast density for 3105 of the women was classified using the American College of Radiology Breast Imaging Reporting and Data System (BI-RADS) categories, and percentage mammographic breast density among the case patients and control subjects was quantified with a computer-based threshold method. Spearman rank partial correlation coefficient and Pearson's correlation coefficient were used to examine correlations between BI-RADS breast density and BMD and between percentage mammographic breast density and BMD, respectively, in women without breast cancer. Logistic regression was used to examine the association of breast cancer with percentage mammographic breast density and BMD. All statistical tests were two-sided. Results: Neither BI-RADS breast density nor percentage breast density was correlated with hip or spine BMD (correlation coefficient = −.02 and −.01 for BI-RADS, respectively, and −2.06 and .01 for percentage breast density, respectively). Neither hip BMD nor spine BMD had a statistically significant relationship with breast cancer risk. Women with breast density in the highest sextile had an approximately threefold increased risk of breast cancer compared with women in the lowest sextile (odds ratio: 2.7; 95% confidence interval: 1.4–5.4); adjusting for hip or spine BMD did not change the association between breast density and breast cancer risk. Conclusion: Breast density is strongly associated with increased risk of breast cancer, even after taking into account reproductive and hormonal risk factors, whereas BMD, although a possible marker of lifetime exposure to estrogen, is not. Thus, a component of breast density that is independent of estrogen-mediated effects may contribute to breast cancer risk.
Crustal structure and rift flank uplift of the Adare Trough, Antarctica
Authors: Müller R. Dietmar , Cande Steven C. , Stock Joann M. , Keller William R.
Published: November 2005

The Adare Trough, located 100 km northeast of Cape Adare, Antarctica, represents the extinct third arm of a Tertiary spreading ridge between East and West Antarctica. It is characterized by pronounced asymmetric rift flanks elevated up to over 2 km above the trough's basement, accompanied by a large positive mantle Bouguer anomaly. On the basis of recently acquired seismic reflection and ship gravity data, we invert mantle Bouguer anomalies from the Adare Trough and obtain an unexpectedly large oceanic crustal thickness maximum of 9–10.5 km underneath the extinct ridge. A regional positive residual basement depth anomaly between 1 and 2.5 km in amplitude characterizes ocean crust from offshore Victoria Land to the Balleny Islands and north of Iselin Bank. The observations and models indicate that the mid/late Tertiary episode of slow spreading between East and West Antarctica was associated with a mantle thermal anomaly. The increasing crustal thickness toward the extinct ridge indicates that this thermal mantle anomaly may have increased in amplitude through time during the Adare spreading episode. This scenario is supported by a mantle convection model, which indicates the formation and strengthening of a major regional negative upper mantle density anomaly in the southwest Pacific in the last 50 million years. The total amount of post‐26 Ma extension associated with Adare Trough normal faulting was about 7.5 km, in anomalously thick oceanic crust with a lithospheric effective elastic thickness (EET) between 3.5 and 5 km. This corresponds to an age between 3 and 5 million years based on a thermal boundary layer model and supports a scenario in which the Adare Trough formed soon after spreading between East and West Antarctica ceased, confined to relatively weak lithosphere with anomalously thick oceanic crust. There is little evidence for major subsequent structural activity in the Adare trough area from the available seismic data, indicating that this part of the West Antarctic Rift system became largely inactive in the early Miocene, with the exception of minor structural reactivation which is visible in the seismic data as offsets up to end of the early Pliocene.
Non‐saturation of the defect moment of goethite and fine‐grained hematite up to 57 Teslas
Authors: Rochette Pierre , Mathé Pierre‐Etienne , Esteban Lionel , Rakoto Harison , Bouchez Jean‐Luc , Liu Qingsong , Torrent José
Published: November 2005

Defect moment of antiferromagnets yields the highest remanent coercivity observed among minerals, and previous studies have been unable to reach saturation of isothermal remanent magnetization (IRM) in some goethite and hematite, even up to 20 Teslas, using resistive Bitter magnets. To go further, acquisition of IRM at room temperature has been monitored on various natural and synthetic goethite and hematite samples in pulsed magnetic fields up to 57 Teslas. “Coarse” hematite is saturated around 5 T, and low unblocking temperature (TB, i.e. with low crystallinity or Al substitution) goethites saturate around 20 T. Higher TB goethites and a Mn‐bearing fine‐grained hematite are still not saturated even at 57 T, with only 2 to 10 percent of the maximum IRM acquired in 3 T. Half acquisition fields are mostly above 10 T. This indicates that usual rock magnetic techniques strongly underestimate the contribution of such minerals to remanence. IRM acquisition is strongly irreversible: in some samples a 57 T backfield is unable to erase a previous 38 T IRM. A field induced defect diffusion model is put forward to account for remanence acquisition in these materials.
A computationally efficient nonstationary convective gravity‐wave drag parameterization for global atmospheric prediction systems
Authors: Kim Young‐Joon , Chun Hye‐Yeong
Published: November 2005

We extend the Chun‐Baik parameterization of convectively forced stationary gravity‐wave drag by adding a set of discrete nonzero phase speeds to incorporate the effects of nonstationary gravity waves. The extended scheme is computationally very efficient in comparison with full spectral parameterizations and eliminates the need to specify the wave source information at the interface level. We validate the extended parameterization against an explicit simulation of convection over a tropical ocean. The distribution of the cloud‐top momentum flux for a typical range of phase speeds is roughly similar to those from more refined studies. It is shown that nonstationary waves should be included to reproduce the vertical variation of explicitly simulated momentum flux.
Changes in the flow of Atlantic water into the Arctic Ocean since the last deglaciation: Evidence from the northern Svalbard continental margin, 80°N
Authors: Ślubowska Marta A. , Koç Nalân , Rasmussen Tine L. , Klitgaard‐Kristensen Dorthe
Published: November 2005

The Svalbard archipelago is located in the high Arctic (76°–80°N) within the northernmost reach of the West Spitsbergen Current, which is the continuation of the North Atlantic Current. In this specific setting close to the Polar Front, even small variations in the current system are expected to give large and distinct signals in paleoceanographic parameters. Thus the Svalbard area is ideal for monitoring the past history of the inflow of Atlantic water to the Arctic Ocean. We have studied sediment core NP94‐51 taken outside the mouth of the Hinlopen Strait on the northern Svalbard shelf. The paleoceanographic development of the last deglaciation and the Holocene has been reconstructed using benthic and planktonic foraminifera, oxygen isotopes, and ice‐rafted detritus. The results show that the first strong subsurface inflow of Atlantic water to the Arctic Ocean after the Last Glacial Maximum commenced at 12.6 14C kyr B.P. (circa 15,000 calendar (cal) years B.P.) during the Bølling‐Allerød interstadial. During the Younger Dryas, polar conditions prevailed at the surface with extensive sea ice cover, and the inflow of Atlantic‐derived water was generally diminished. The inflow of more saline, but still cold Atlantic water was relatively strong during the early Holocene and caused intensified seasonal biological productivity. The Atlantic water inflow declined gradually during the mid‐Holocene. Between 4500 and 1100 cal years B.P. the inflow was very weak, and the bottom waters over the northern Svalbard margin were cold and of lower salinity. During the last ∼1000 years, climatic conditions improved such that the subsurface inflow of Atlantic‐derived water increased. However, the surface waters were still cold.
SPORE SUPPLY AND HABITAT AVAILABILITY AS SOURCES OF RECRUITMENT LIMITATION IN THE GIANT KELP MACROCYSTIS PYRIFERA (PHAEOPHYCEAE)1
Authors: Reed Daniel C. , Schroeter Stephen C. , Raimondi Peter T.
Published: November 2005

The causes of spatial variation in the recruitment of benthic marine algae are frequently misunderstood because of difficulties in distinguishing among the many factors that influence the supply and establishment of microscopic propagules. We used the recently constructed San Clemente Artificial Reef (SCAR) experiment to examine the roles of dispersal distance, size of spore source, and habitat availability as sources of variation in the recruitment of the giant kelp Macrocystis pyrifera (L.) C. Ag., a species whose recruitment has often been considered to be dispersal limited. Sparse colonization on SCAR by adult Macrocystis occurred within 6 months after reef construction via drifters (i.e. individuals from neighboring kelp beds that became dislodged and set adrift). The abundance of drifters on SCAR declined exponentially with distance from the nearest source population (San Mateo), suggesting that San Mateo was the likely source of drifters. Dense recruitment of small Macrocystis sporophytes was observed within 8 months of reef construction. The density of recruits on SCAR showed an initial increase with distance from San Mateo before declining exponentially. Nonetheless, substantial recruitment was observed at the most distant locations on SCAR located 3.5 km from San Mateo. In contrast to drifters, the density of recruits was positively correlated to the bottom cover of artificial reef substrate. Importantly, no correlation was found between the local density or fecundity of drifters and the local density of kelp recruits suggesting that recruitment on SCAR resulted from widespread spore dispersal rather than from the local dispersal of spores from drifters.
On fitting a gold embedded atom method potential using the force matching method
Authors: Grochola Gregory , Russo Salvy P. , Snook Ian K.
Published: November 2005

We fit a new gold embedded atom method (EAM) potential using an improved force matching methodology which included fitting to high-temperature solid lattice constants and liquid densities. The new potential shows a good overall improvement in agreement to the experimental lattice constants, elastic constants, stacking fault energy, radial distribution function, and fcc/hcp/bcc lattice energy differences over previous potentials by Foiles, Baskes, and Daw (FBD) [Phys. Rev. B 33, 7983 (1986)] Johnson [Phys. Rev. B 37, 3924 (1988)], and the glue model potential by Ercolessi et al. [Philos. Mag. A 50, 213 (1988)]. Surface energy was improved slightly as compared to potentials by FBD and Johnson but as a result vacancy formation energy is slightly inferior as compared to the same potentials. The results obtained here for gold suggest for other metal species that further overall improvements in potentials may still be possible within the EAM framework with an improved fitting methodology. On the other hand, we also explore the limitations of the EAM framework by attempting a brute force fit to all properties exactly which was found to be unsuccessful. The main conflict in such a brute force fit was between the surface energy and the liquid lattice constant where both could not be fitted identically. By intentionally using a very large number of spline sections for the pair potential, electron-density function, and embedding energy function, we eliminated a lack of functional freedom as a possible cause of this conflict and hence can conclude that it must result from a fundamental limitation in the EAM framework.
Vibrational mode and collision energy effects on reaction of H2CO+ with C2H2: Charge state competition and the role of Franck-Condon factors in endoergic charge transfer
Authors: Liu Jianbo , Van Devener Brian , Anderson Scott L.
Published: November 2005

The effects of collision energy (Ecol) and six different H2CO+ vibrational states on the title reaction have been studied over the center-of-mass Ecol range from 0.1 to 2.6 eV, including measurements of product ion recoil velocity distributions. Ab initio and Rice-Ramsperger-Kassel-Marcus calculations were used to examine the properties of complexes and transition states that might be important in mediating the reaction. Reaction is largely direct, despite the presence of multiple deep wells on the potential surface. Five product channels are observed, with a total reaction cross section at the collision limit. The competition among the major H2+ transfer, hydrogen transfer, and proton transfer channels is strongly affected by Ecol and H2CO+ vibrational excitation, providing insight into the factors that control competition and charge state “unmixing” during product separation. One of the more interesting results is that endoergic charge transfer appears to be controlled by Franck-Condon factors, implying that it occurs at large inter-reactant separations, contrary to the expectation that endoergic reactions should require intimate collisions to drive the necessary energy conversion.
Photocathode microwire monitor for nondestructive and highly sensitive spatial profile measurements of ultraviolet, x-ray, and charged particle beams
Authors: Hori Masaki
Published: November 2005

A nondestructive and sensitive monitor consisting of photocathode wire grids arranged in an XY configuration for measuring the spatial profile, divergence, and intensity of pulsed UV, x-ray, and charged particle beams is described. The monitor has been used to measure laser beams at wavelengths λ=213−532nm, and antiproton, proton, H− ions, and electron beams of energies E=50eV to 5 MeV.
Line and two-dimensional fractal analysis of micrographs obtained by atomic force microscopy of surface-immobilized oligonucleotide nano-aggregates
Authors: Sawant Prashant D. , Nicolau Dan V.
Published: November 2005

This study reports on the evaluation of the nanotopographies of DNA functionalized polymer surfaces, i.e., cyclo-olefine copolymer (COC) and polycarbonate (PC) using line, “Zmax” and two dimensional fractal dimension methods, i.e., power spectrum density algorithm (PSDA) and perimeter-area relationship (PAR), applied to atomic force microscopy (AFM) scans. A decrease in the fractal dimension after the immobilization of oligonucleotides suggests the prevalence of a vertical assembly of oligonucleotides, more significantly on COC than on PC.
Up-to-date radon-thoron discriminative detector for a large scale survey
Authors: Tokonami Shinji , Takahashi Hiroyuki , Kobayashi Yosuke , Zhuo Weihai , Hulber Erik
Published: November 2005

An up-to-date radon-thoron discriminative detector has been developed for conducting a large scale survey. Comparing with our previous detector, some functional problems have been solved. The lowest and highest detection limits of the detector were estimated to be around 5 and 1000Bqm−3 for radon, and 15 and 1000Bqm−3 for thoron, respectively, with a 6month exposure and several theoretical assumptions. Small indoor survey were carried out in Japan and in Hungary using the present detector. The presence of thoron was demonstrated in any indoor surveys by the two results. Since any measurements without discrimination of radon isotopes will result in different risk estimates from actual situations, a special attention should be paid to thoron and its concentration should be accordingly measured as well as the radon concentration.
Monolithically integrated tunable external-cavity laser diode using InP-based planar waveguide collimating lens and optical deflector
Authors: Kim Hyun-Soo , Sim Eun-Deok , Kim Kang Ho , Kwon Oh Kee , Kim Jong-Hoi , Oh Kwang-Ryong
Published: November 2005

A lensless tunable external-cavity laser diode monolithically integrated with InP-based planar waveguide parabolic-shaped collimating lens, optical deflector, and echelle grating is proposed and demonstrated in this work. The tunable laser exhibits a total wavelength tuning range of 9.3 nm with a side mode suppression ratio of about 35 dB by adjusting the applied current of optical deflectors and phase control section.
Magneto-optical measurement of Barkhausen noise spectra
Authors: Pinotti Ermanno , Zani Maurizio , Puppin Ezio
Published: November 2005

Magneto-optical techniques are increasingly employed for measurements of Barkhausen noise in ferromagnetic materials, especially for very thin films and microstructured samples, where the usual pickup coil or surface probe methods can be difficult to apply. Among the information that can be extracted from the Barkhausen signal, the noise power spectrum is of relevance because it gives important clues about the dynamics of the avalanches during the magnetization process. In this paper we propose a method for obtaining the Barkhausen noise spectra by means of magneto-optical Kerr effect measurements. We describe the experimental setup and the numerical elaboration of the signal, and we illustrate the advantages and the perspectives of this method.
A simple far-infrared laser interferometer for measuring electron densities in reactive low-temperature plasmas
Authors: Pargmann C. , Singh S. V. , Soltwisch H.
Published: November 2005

A sensitive far-infrared (fir) interferometer for electron density measurements in reactive low-temperature plasmas is described. The instrument is based on an optically pumped fir laser (wavelength range 50–600μm depending on the working gas) and makes use of the nonlinear relation between output power and cavity loss. The fir beam, which leaves the resonator through a coupling hole in the end mirror, is reflected back into the cavity, such that the coupling hole behaves like a variable “leak” with a loss rate depending on the phase of the reentering wave relative to the standing wave within the resonator. As a result of the feedback, the output intensity undergoes strong nonlinear variations if the optical distance of the external mirror is changed by small amounts, Δz. The power variation is monitored through a small opening in the external mirror. Test experiments using a wavelength of 432.6μm and a Schottky-diode detector have yielded a minimum detectable pathlength variation of Δz=0.4μm, corresponding to a change of the line-integrated electron density n¯e×L of about 5×1015m−2. A first application to argon plasmas in inductively coupled rf discharges has been made, and the results have been compared to concomitant Langmuir probe measurements.
Compact implementation of a scanning transfer cavity lock
Authors: Burke John H. T. , Garcia Ofir , Hughes K. Jeramy , Livedalen Brian , Sackett Charles A.
Published: November 2005

We describe an implementation of a scanning transfer cavity laser lock that is based on a commercial optical spectrum analyzer and an inexpensive computer microcontroller. The lock performs as well as a standard saturated absorption lock for frequency differences of several GHz. It offers the advantages of locking at arbitrary frequencies, having a large capture range, and allowing complex control mechanisms to be implemented via software.
Laser Thomson scattering system applicable to low-temperature plasma in the divertor simulator MAP-II
Authors: Okamoto A. , Kado S. , Kajita S. , Tanaka S.
Published: November 2005

A laser Thomson scattering system was developed for the measurement of electron temperature in low-temperature recombining plasmas. The system is equipped with a double monochromator instead of an interference filter array to obtain narrow Doppler broadening. The system was applied to electron temperature measurement in the divertor simulator MAP-II. When the electron temperature is lowered to 2 eV by puffing hydrogen gas, a signature of hydrogen molecular-assisted recombination (H2-MAR) is observed.
Determination of room-temperature creep of soft lead zirconate titanate piezoceramics under static electric fields
Authors: Zhou Dayu , Kamlah Marc
Published: November 2005

This study focuses on the experimental investigation of the time-dependent effects of a commercial soft lead zirconate titanate material at room temperature. Samples in initially unpoled states were subjected to a cyclic stepwise electric field which was kept constant at different levels for 300 s. Due to ferroelectric domain switching, significant nonlinearity and hysteresis were observed in the overall polarization and strain response. In particular, the material exhibited creep behavior as the applied electric field was held constant over extended periods of time. This creep was caused by microscopic domain switching processes induced gradually during the holding time. The creep was of primary or transient type in nature and depended strongly on the magnitude of the load applied. Most pronounced creep was observed when holding the field close to the coercive field. Logarithmic representation of the polarization or strain versus time curves indicated that the creep behavior could be quantified approximately by the Andrade power law. The creep exponents were determined for different field conditions. The results may help the understanding of the creep mechanism, which in turn provides contributions to improve the performance and reliability of ultrahigh-precision positioning piezoactuators.
Patterson-like analysis of diffuse x-ray scattering from epitaxial mosaic PbTe layers on Si(111)
Authors: Daniš S. , Holý V. , Zimin D. , Zogg H.
Published: November 2005

A simple approach for the analysis of mosaic epitaxial layers is proposed, based on a Patterson-like analysis of the reciprocal-space distribution of the scattered intensity. Within this approach, the mosaic-block-shape function P and the deformation correlation function are determined. The method is used for the analysis of relaxed PbTe epitaxial layers on Si(111). The sizes of the mosaic blocks determined by this method are compared with the results of conventional Williamson-Hall-type analyses of the width of the diffraction maxima. The block sizes compare well with the mean distances of threading dislocations penetrating the PbTe layers.
Band edge and defect modes lasing due to confinement of helixed liquid crystals in cylindrical microcavities
Authors: Barna V. , Ferjani S. , De Luca A. , Caputo R. , Scaramuzza N. , Versace C. , Strangi G.
Published: November 2005

Peculiar light emission properties have been observed in cylindrical microcavity hosting dye-doped helixed liquid crystals, which behaves as a fiber-like multidirectional distributed feedback laser. Experimental studies performed for this level of confinement show that laser action is exhibited both axially and radially, indicating a self-organized three-dimensional blue phase-like configuration. Thermal wavelength tunability was observed for both orientations emphasizing two different linear behaviors. The distributed feedback mechanism and the Q factor of the mirrorless resonant cavity result enhanced for axial stimulated emission because of the significant increase in the number of helical periods. In addition, long-lived spectrally narrow defect modes appear within the photonic band gap owing to optical phase jumps which take place in local structural defects.
Visualization of the diffusion path in the fast oxide-ion conductor Bi1.4Yb0.6O3
Authors: Yashima Masatomo , Ishimura Daiju
Published: November 2005

Accurate nuclear-density distribution of bismuth oxide solution Bi1.4Yb0.6O3 compound has been studied at 384 °C and at 738 °C by the maximum-entropy method (MEM) and MEM-based pattern fitting combined with the Rietveld method using neutron powder diffraction data. The results reveal that the oxide ions have a complicated disorder spreading over a wide area, shift to the ⟨111⟩ directions from the ideal fluorite position and diffuse along the ⟨100⟩ directions.
Double optical tweezers for ultrasensitive force spectroscopy in microsphere Mie scattering
Authors: Fontes A. , Neves A. A. R. , Moreira W. L. , de Thomaz A. A. , Barbosa L. C. , Cesar C. L. , de Paula A. M.
Published: November 2005

We used a double tweezers setup to perform ultrasensitive force spectroscopy and observe the forces due to light scattering in a single isolated particle. We demonstrate how to selectively couple the light to the transverse electric (TE), transverse magnetic (TM), or both TE and TM microsphere modes by means of the beam polarization and positioning, and to observe correspondent morphology-dependent resonances (MDR). The results show how the usually assumed azimuthal symmetry in the horizontal plane no longer holds because of the symmetry break caused by the beam polarization. Also, the MDR resonances can change the force values by more than 30–50%.
Flexible organic static induction transistors using pentacene thin films
Authors: Watanabe Yasuyuki , Kudo Kazuhiro
Published: November 2005

Flexible organic static induction transistors (OSITs) based on pentacene thin films are fabricated on plastic substrates and their static characteristics are measured. The basic transistor characteristics of the flexible pentacene OSITs were comparable to those of nonflexible pentacene OSITs fabricated on glass substrates. In addition, variation in the static characteristics was negligible up to a bending radius of 20 mm. These characteristics suggest the potential for the OSITs as drivers in flexible sheet displays, such as organic light-emitting transistors in which the OSITs are combined with organic light-emitting transistors.
Bidomain state in exchange biased FeF2∕Ni
Authors: Petracic O. , Li Zhi-Pan , Roshchin Igor V. , Viret M. , Morales R. , Batlle X. , Schuller Ivan K.
Published: November 2005

Independently exchange biased subsystems can coexist in ferromagnet/antiferromagnet bilayers after various field-cooling protocols. We find well separated double hysteresis loops in FeF2∕Ni bilayers for intermediate cooling fields, while for small or large cooling fields a negatively or positively shifted single loop, respectively, are encountered. The antiferromagnet breaks into a bidomain state with opposite signs but equal magnitude of bias acting on the ferromagnet. This idea is supported by micromagnetic simulations. Experiments are presented, where thermally activated motion of these antiferromagnetic domain boundaries can be achieved.
Photopumped laser oscillation and charge-injected luminescence from organic semiconductor single crystals of a thiophene/phenylene co-oligomer
Authors: Ichikawa Musubu , Nakamura Kiyoshi , Inoue Masamitsu , Mishima Hiromi , Haritani Takeshi , Hibino Ryota , Koyama Toshiki , Taniguchi Yoshio
Published: November 2005

We have demonstrated that single crystals of a thiophene/phenylene co-oligomer [α,ω-bis-biphenyl-4-yl-terthiophene (BP3T)] show interesting photonic aspects: (1) the self-waveguided amplified spontaneous light emissions with a comparable low threshold of 8μJ∕cm2 to other optimized organic solid-state laser systems, and (2) the laser oscillation based on the optical self-confinement effect in the crystals. We have also presented electroluminescence from the crystals based on bipolar injection and the crystals’ tolerance for intense current driving. These achievements strongly imply that BP3T crystals are a promising candidate for organic laser diodes.
Experimental evidence of the “dead layer” at Pt∕BaTiO3 interface
Authors: Li X. L. , Chen B. , Jing H. Y. , Lu H. B. , Zhao B. R. , Mai Z. H. , Jia Q. J.
Published: November 2005

The Pt∕BaTiO3 (BTO) interface was investigated by angle-resolved x-ray photoelectron spectroscopy and x-ray reflectivity technique. It was shown that there exists a transition layer of about 9Å at the Pt/BTO interface with electron density lower than that of the BTO film. The transition layer shows a higher binding energy of Ba 3d than that of the bulk BTO. Moreover, neither the interdiffusion of BTO and Pt nor the oxidation of Pt near the interface had been observed. We consider that this layer is caused by “interface-induced relaxation.” This relaxation layer is believed to be the origin of the “dead layer” effect.
Diel changes of inorganic chemistry in a macrophyte-dominated, softwater stream
Authors: Wilcock Robert J. , Chapra Steven C.
Published: November 2005

Diel fluctuations of conductivity and alkalinity were measured in a macrophyte-dominated stretch of the Piako River, a rural, lowland, softwater stream in New Zealand. Both quantities exhibited elevated levels at dawn and depressed levels in the early evening suggesting that the variations might be connected with the diel cycles of macrophyte photosynthesis and respiration. A chemical analysis was used to determine which ions induced the diel variations. For low-flow periods with minimal allochthonous inputs, the changes in conductivity were correlated with calcium, magnesium and the ionised components of total inorganic carbon (bicarbonate, HCO3–, and carbonate, CO32–). The changes in alkalinity were correlated with fluctuations of calcium and magnesium. The latter result was not anticipated based on solubility product calculations. Diel cycles of groundwater inputs explained 60% of average conductivity variations and 30% of average alkalinity variations between dusk and dawn. Other mechanisms also contribute to the observed changes and we speculate that localised calcite production and dissolution may be occurring.
Death model for tussock perennial grasses: a rainfall threshold for survival and evidence for landscape control of death in drought
Authors: Hodgkinson K. C. , Müller W. J.
Published: November 2005

We investigated relationships between rainfall (and landscape, zonation and nearby grazing disturbance) and the death rates of four perennial grass species in a highly functional semi-arid wooded grassland in eastern Australia. Two grasses were palatable C3 species (Monachather paradoxa Steud. and Thyridolepis mitchelliana (Nees) S. T. Blake) and two were unpalatable C4 species (Aristida jerichoensis (Domin) Henr. var. subspinulifera Henr. and Eragrostis eriopoda Benth.). During the 10-year study the grasses were protected from large herbivore grazing within paddocks continuously grazed by sheep. Death occurred only during droughts and rates of death were species-dependent. When plotted against several water availability indices, rainfall and rainfall/evaporation during the preceding 3 months provided best predictions of death. Longer preceding periods gave inferior predictions. A 3-month rainfall total of 75 mm and a 3-month rainfall/evaporation ratio of 0.15 were survival critical thresholds below which deaths began. The 3-month rainfall totals, rainfall/evaporation and estimated water status of plants were equally reasonable predictors of deaths, but were inconsistent in their effectiveness. Rainfall was adopted for the grass death model; death begins when 3-month rainfall total declines below a threshold of 75 mm and the death rate rises with lower rainfall. Position of plants in the gently undulating landscapes influenced water status and, hence, death rates. Water status of grasses on the two water-shedding zones and the ‘flat’ zone were similar at each assessment, but higher on ‘ridge run-on’ and ‘toe-of-slope’ zones. Foliage height and diameter also influenced death rate but were species dependent. Basal diameter did not influence death rate. Survivorship of several perennial grass species at widely spaced sites in south-eastern Australia provided equivocal support for generality of the grass death model.
Integrated shrub management in semi-arid woodlands of eastern Australia: ground and aerial application of defoliant to shrubs regenerating after disturbance
Authors: Noble J. C. , Müller W. J. , MacLeod N. D. , Bodulovic Z. , Jones P. , Wood J. T.
Published: November 2005

This paper describes experiments undertaken at several sites in semi-arid woodlands of eastern Australia to determine if chemicals applied either on the ground or from the air reduce the density of shrubs regenerating after disturbance. Ground-spraying of Roundup® in the autumn was more effective than spring application in defoliating shrubs, especially 2-year-old coppice growth. Spraying of Roundup with a hand-held boom at 0.5 up to 2.5 kg glyphosate/ha identified rates to be used for boom spraying. Aerial spraying experiments were then undertaken across several sites and involved several target species. The location of sufficiently large areas where shrub regeneration was of an optimum age (i.e. about 2–3 years) proved to be extremely difficult due to prevailing drought conditions precluding the use of prescribed fire as a preliminary treatment. Nonetheless in one experiment, young (1-year-old) regrowth of firebush (Senna pleurocarpa) exhibited increased sensitivity to Roundup with significant shoot mortality recorded after it had been applied at 0.5 kg glyphosate/ha. Aerial spraying based on an ultra-low volume application of 10 L/ha further enhanced cost-effectiveness on this occasion. Economic analyses structured around 20-year partial budgeting and determination of net present value (NPV) suggested a profitable return could be expected where treatment was based on Roundup applied at this threshold rate 2 years after a prescribed fire, especially when the rehabilitation costs were spread over an entire paddock that had been only partially sprayed. Finally, operational aspects involving aerial spraying in these semi-arid woodlands are also discussed.
Pasture production in cleared and uncleared grazing systems of central Queensland, Australia
Authors: Kaur K. , Jalota R. K. , Midmore D. J. , Rolfe J.
Published: November 2005

Clearing land of trees and introducing exotic pastures to enhance pasture and cattle production and hence enterprise financial performance are widely practised in Queensland. The results from many previous studies on tree clearing have emphasised the gains in pasture production, but over periods of less than 10–15 years after clearing. The present study questioned the sustainability of pasture production in cleared systems over a longer time-frame (>10 years of clearing). For this, three different age groups of clearing i.e. 5 year, 11–13 year and 33 year were selected in each of 3 major types of tree communities i.e. Eucalyptus populnea, E. melanophloia and Acacia harpophylla in central Queensland. Paired comparisons of cleared and uncleared (intact) pasture systems were selected for each age group of clearing. The results suggest that the initial gains in pasture production upon clearing were compatible with published studies. However, for longer periods of time since clearing, the gains in pasture production were not sustained and were accompanied by risks of land degradation and loss of pasture plant diversity. For E. populnea and A. harpophylla, the maximum benefits from clearing were achieved at 13–15 years whereas for E. melanophloia, any benefits existed only over a short period of 5–6 years. The study emphasises that each tree community exhibits a specific response with regard to the duration of increased pasture production following clearing. To estimate the total benefits from tree clearing in pasture development, it is important to consider both monetary benefits and non-monetary losses from clearing for different types of tree communities.
Charting biologically relevant chemical space: A structural classification of natural products (SCONP)
Authors: Koch Marcus A. , Schuffenhauer Ansgar , Scheck Michael , Wetzel Stefan , Casaulta Marco , Odermatt Alex , Ertl Peter , Waldmann Herbert
Published: November 2005

The identification of small molecules that fall within the biologically relevant subfraction of vast chemical space is of utmost importance to chemical biology and medicinal chemistry research. The prerequirement of biological relevance to be met by such molecules is fulfilled by natural product-derived compound collections. We report a structural classification of natural products (SCONP) as organizing principle for charting the known chemical space explored by nature. SCONP arranges the scaffolds of the natural products in a tree-like fashion and provides a viable analysis- and hypothesis-generating tool for the design of natural product-derived compound collections. The validity of the approach is demonstrated in the development of a previously undescribed class of selective and potent inhibitors of 11β-hydroxysteroid dehydrogenase type 1 with activity in cells guided by SCONP and protein structure similarity clustering. 11β-hydroxysteroid dehydrogenase type 1 is a target in the development of new therapies for the treatment of diabetes, the metabolic syndrome, and obesity.
Frequency effects in compound production
Authors: Bien Heidrun , Levelt Willem J. M. , Baayen R. Harald
Published: November 2005

Four experiments investigated the role of frequency information in compound production by independently varying the frequencies of the first and second constituent as well as the frequency of the compound itself. Pairs of Dutch noun-noun compounds were selected such that there was a maximal contrast for one frequency while matching the other two frequencies. In a position-response association task, participants first learned to associate a compound with a visually marked position on a computer screen. In the test phase, participants had to produce the associated compound in response to the appearance of the position mark, and we measured speech onset latencies. The compound production latencies varied significantly according to factorial contrasts in the frequencies of both constituting morphemes but not according to a factorial contrast in compound frequency, providing further evidence for decompositional models of speech production. In a stepwise regression analysis of the joint data of Experiments 1-4, however, compound frequency was a significant nonlinear predictor, with facilitation in the low-frequency range and a trend toward inhibition in the high-frequency range. Furthermore, a combination of structural measures of constituent frequencies and entropies explained significantly more variance than a strict decompositional model, including cumulative root frequency as the only measure of constituent frequency, suggesting a role for paradigmatic relations in the mental lexicon.