bluuebunny/crossref_metadata_2025 huggingface dataset:
Scanning probe lithography tips with spring-on-tip designs: Analysis, fabrication, and testing
Authors: Wang Xuefeng , Vincent Loren , Bullen David , Zou Jun , Liu Chang
Published: July 2005

This letter reports a special tip design for probes used in scanning probe lithography applications. The sidewalls of the pyramidal tip located at the distal end of a cantilever probe are modified to contain folded spring structures to reduce the overall force constant of the scanning probe. The spring structure is generated using focused ion beam milling method. We have conducted finite element simulation of the force constants of such folded springs under various geometries. We also demonstrated sub-100nm scanning probe lithography using a modified spring tip in the dip pen nanolithography writing mode.
Influence of surface stress on the resonance behavior of microcantilevers
Authors: McFarland Andrew W. , Poggi Mark A. , Doyle Margaret J. , Bottomley Lawrence A. , Colton Jonathan S.
Published: July 2005

This work presents a model to predict the effect of surface stresses on the ith-mode bending resonant frequency of microcantilevers and its experimental validation. With this model, one can calculate the surface stress acting upon the microcantilever solely by measuring resonant frequencies whereas previously one needed to measure the deflection. Resonant frequency measurement has distinct advantages in terms of ease and accuracy of measurement.
Electrical control of polariton coupling in intersubband microcavities
Authors: Anappara Aji A. , Tredicucci Alessandro , Biasiol Giorgio , Sorba Lucia
Published: July 2005

We demonstrate the external control of the coupling between the intersubband transition and the photonic mode of a GaAs∕AlGaAs microcavity with multiple quantum wells embedded. By electrical gating, the charge density in the wells can be lowered, thereby quenching the intersubband polaritons and reverting the system to uncoupled excitations. The angle-dependent reflectance measurements are in good agreement with theoretical calculations performed in the transfer matrix formalism. The experiment shows the prospects offered by intersubband microcavities through manipulation of the system ground state.
Modulation of the work function of silicon gate electrode using thin TaN interlayers
Authors: Alshareef H. N. , Wen H. C. , Harris H. R. , Choi K. , Luan H. F. , Lysaght P. , Majhi P. , Lee B. H. , El-Bouanani M. , Ukride V.
Published: July 2005

The impact of thin TaN layers (0.5–10nm) on the effective work function of polycrystalline silicon (poly-Si)∕TaN stacks has been investigated. It is found that when the TaN layer is as thin as 0.5nm, it can have a significant effect on the effective work function of poly-Si, and that n-type and p-type poly-Si behave differently. The observed results are explained by reactions between poly-Si and the TaN layer leading to the formation of TaxSiyNz at the poly-Si-gate dielectric interface. Electrical tests show minimal poly-Si depletion with the TaN layers, and gate leakage current and fixed charges that are comparable to conventional poly-Si electrodes. The results show that these stacked electrodes can be useful for nearly n-type effective work functions (4.2–4.3eV).
Nuclear magnetic resonance in the nanoTesla range
Authors: Burghoff Martin , Hartwig Stefan , Trahms Lutz , Bernarding Johannes
Published: July 2005

At ultralow fields of 40nTto4μT magnetic flux density, nuclear magnetic resonance spectra of a resolution well below 1Hz were obtained, which is beyond what usually is achieved in the conventional high-field regime. The spectral resolution of our setup allows for the direct observation of the natural linewidth of distilled water. For heteronuclear systems, this enables pure J-spectroscopy in the absence of a chemical shift, with a resolution that is limited only by the natural width of the resonance lines.
Effects of applied electric field during postannealing on the tunable properties of (Ba,Sr)TiO3 thin films
Authors: Xia Yidong , Cheng Jinbo , Pan Bai , Wu Di , Meng Xiangkang , Liu Zhiguo
Published: July 2005

The impact of postannealing in electric field on the structure, tunability, and dielectric behavior of rf magnetron sputtering derived (Ba,Sr)TiO3 films has been studied. It has been demonstrated that postannealing in the proper electric field can increase the dielectric constant and the tunability remarkably and destroy the symmetry of capacitance-voltage characteristics of the films. The increased out-of-plane lattice constant and the appearance of the hysteresis loops in the electric-annealed films indicated the formation of small polar regions with tetragonal structure, which are responsible for the increased dielectric constant and tunability. It was proposed that the segregation of Ti3+ ions caused by electric annealing could induce the formation of BaTiO3-like regions, which are ferroelectric at room temperature.
Electromechanical imaging of biological systems with sub-10nm resolution
Authors: Kalinin Sergei V. , Rodriguez B. J. , Jesse S. , Thundat T. , Gruverman A.
Published: July 2005

Electromechanical imaging of tooth dentin and enamel has been performed with sub-10nm resolution using piezoresponse force microscopy. Characteristic piezoelectric domain size and local protein fiber ordering in dentin have been determined. The shape of a single protein fibril in enamel is visualized in real space and local hysteresis loops are measured. Because of the ubiquitous presence of piezoelectricity in biological systems, this approach is expected to find broad application in high-resolution studies of a wide range of biomaterials.
Metalorganic chemical vapor deposition of atomically flat SrRuO3 films on stepped SrTiO3 substrates
Authors: Sumi Akihiro , Takahashi Kenji , Yokoyama Shintaro , Morioka Hitoshi , Funakubo Hiroshi , Yoshimoto Mamoru
Published: July 2005

Epitaxial SrRuO3 films with thicknesses of 50–80nm were systematically grown at 750°C on (100)SrTiO3 substrates by metalorganic chemical vapor deposition with different supply rates of the Sr and Ru source gases. Stoichiometric films with a low resistivity of 240–260μΩcm can be grown on polished (100)SrTiO3 substrates over a wide range of source gas supply rates. However, the surface flatness of the deposited film was very sensitive to changes the input source gas supply rate. SrRuO3 films having step and trace structured surfaces were grown on polished and atomically flat SrTiO3 substrates under an optimized input gas supply rate. A height of 7–8nm with a terrace width of 500–1000nm were obtained on polished SrTiO3 substrates, but a single unit cell height of about 0.4nm was obtained with a 200–300nm terrace width on atomically flat SrTiO3 substrates. This opens the possibility of the mass production of atomically flat conductive perovskite layers.
Mechanical stability of a flexible ferroelectric liquid crystal display with a periodic array of columnar spacers
Authors: Kim Dong-Woo , Yu Chang-Jae , Lim Yong-Woon , Na Jun-Hee , Lee Sin-Doo
Published: July 2005

We report on a high-speed flexible display based on a deformed helix ferroelectric liquid crystal (DHFLC) in a vertically aligned configuration. The mechanical stability of the flexible DHFLC display was achieved using a periodic array of columnar spacers formed directly on the top side of in-plane electrodes by the photolithography technique. Several unique features of display performances such as flexibility, uniform alignment, fast response, and gray scale capability were obtained. The switching time was found to be a few hundred microseconds.
Reversal of doping-induced energy level shift: Au on Cs-doped tris(8-hydroxyquinoline) aluminum
Authors: Ding Huanjun , Gao Yongli
Published: July 2005

We investigated the electronic structure of the interface formed by depositing Au on Cs-doped tris(8-hydroxyquinoline) aluminum (Alq) film using ultraviolet and x-ray photoemission spectroscopy. The initial Au deposition quenches the Alq gap state caused by Cs doping. Further Au depositions gradually shift the energy levels opposite to that induced by Cs doping, especially the highest occupied molecular orbital that shows approximately full recovery to the pristine Alq position. However, the recovery is only partial for the other levels, most noticeably the C 1s core level.
Electrical characterization of band gap states in C-doped TiO2 films
Authors: Nakano Yoshitaka , Morikawa Takeshi , Ohwaki Takeshi , Taga Yasunori
Published: July 2005

We report on band gap states in C-doped TiO2 films that were prepared by oxidative annealing of sputtered TiC films at 550°C in flowing O2 gas. Deep-level optical spectroscopy measurements revealed three deep levels located at ∼0.86, ∼1.30, and ∼2.34eV below the conduction band. The first level is probably attributable to the intrinsic nature of TiO2, whereas the latter two levels are newly introduced by the C-doping. In particular, the pronounced 2.34eV band contributes to band gap narrowing by mixing with the O 2p valence band. Additionally, the 0.86 and 1.30eV levels can be active as an efficient generation-recombination center.
The Ponzo Illusion with Auditory Substitution of Vision in Sighted and Early-Blind Subjects
Authors: Renier L , Laloyaux C , Collignon O , Tranduy D , Vanlierde A , Bruyer R , De Volder A G
Published: July 2005

We tested the effects of using a prosthesis for substitution of vision with audition (PSVA) on sensitivity to the Ponzo illusion. The effects of visual experience on the susceptibility to this illusion were also assessed. In one experiment, both early-blind and blindfolded sighted volunteers used the PSVA to explore several variants of the Ponzo illusion as well as control stimuli. No effects of the illusion were observed. The results indicate that subjects focused their attention on the two central horizontal bars of the stimuli, without processing the contextual cues that convey perspective in the Ponzo figure. In a second experiment, we required subjects to use the PSVA to consider the two converging oblique lines of the stimuli before comparing the length of the two horizontal bars. Here we were able to observe susceptibility to the Ponzo illusion in the sighted group, but to a lesser extent than in a sighted non-PSVA control group. No clear effect of the ilusion was obtained in early-blind subjects. These results suggest that, at least in sighted subjects, perception obtained with the PSVA shares perceptual processes with vision. Visual experience appears mandatory for a Ponzo illusion to occur with the PSVA.
Perceptual Alternation Induced by Visual Transients
Authors: Kanai Ryota , Moradi Farshad , Shimojo Shinsuke , Verstraten Frans A J
Published: July 2005

When our visual system is confronted with ambiguous stimuli, the perceptual interpretation spontaneously alternates between the competing incompatible interpretations. The timing of such perceptual alternations is highly stochastic and the underlying neural mechanisms are poorly understood. We show that perceptual alternations can be triggered by a transient stimulus presented nearby. The induction was tested for four types of bistable stimuli: structure-from-motion, binocular rivalry, Necker cube, and ambiguous apparent motion. While underlying mechanisms may vary among them, a transient flash induced time-locked perceptual alternations in all cases. The effect showed a dependence on the adaptation to the dominant percept prior to the presentation of a flash. These perceptual alternations show many similarities to perceptual disappearances induced by transient stimuli (Kanai and Kamitani, 2003 Journal of Cognitive Neuroscience15 664–672; Moradi and Shimojo, 2004 Vision Research44 449–460). Mechanisms linking these two transient-induced phenomena are discussed.
Interactions between Orientation and Contrast Modulations Suggest Limited Cross-Cue Linkage
Authors: Schofield Andrew J , Yates Timothy A
Published: July 2005

Recent studies of texture segmentation and second-order vision have proposed very similar models for the detection of orientation modulation and contrast modulation (OM and CM). From the similarity of the models it is tempting to assume that the two cues might be processed by a single generalised texture mechanism; however, recent results (Kingdom et al, 2003 Visual Neuroscience2 65–76) have suggested that these cues are detected independently, or at least in a mechanism that is able to maintain an apparent independence between the cues. We tested new combinations of OM and CM and found that CM at 0.4 cycle deg−1 facilitates the detection of OM at 0.2 cycle deg−1 when the peaks of contrast align with the extremes of orientation. There is also some evidence of weak facilitation of CM by OM under the same conditions. Further, this facilitation can be predicted by filter-rectify-filter channels optimised for the detection of each cue, adding weight to the argument that texture cues are processed in a single generalised mechanism that nonetheless achieves cue independence or near-independence in many circumstances. We also found that the amount of suprathreshold masking produced by an orientation cue depends on the overall percept formed by that cue.
Haptic Detection of Sine-Wave Gratings
Authors: Louw Stefan , Kappers Astrid M L , Koenderink Jan J
Published: July 2005

We studied human haptic perception of sine-wave gratings. In the first experiment we measured the dependence of amplitude detection thresholds on the number of cycles and on the wavelength of the gratings. In haptic perception of sine-wave gratings, the results are in agreement with neural summation. The rate at which detection thresholds decrease with increasing number of cycles is much higher than can be accounted for by probability summation alone. Further, neural summation mechanisms describe the detection thresholds accurately over the whole spatial range probed in the experiment, that is wavelengths from 14 mm up to 225 mm. Earlier, we found a power-law dependence of thresholds on the spatial width of Gaussian profiles (Louw et al, 2000 Experimental Brain Research132 369–374). The current results extend these findings; the power-law dependence holds not only for Gaussian profiles, but also for a broad range of sine-wave gratings with the number of cycles varying between 1 and 8. Haptic perception involves tactual scanning combined with an active, dynamic exploration of the environment. We measured characteristics of the velocity and force with which stimuli were scanned while performing a psychophysical task. One particularly surprising finding was that, without being instructed, participants maintained an almost constant scanning velocity during each 45-min session. A constant velocity in successive trials of the experiment might facilitate or even be necessary for discrimination. Further, a large systematic dependence of velocity on scanning length was found. An eightfold increase in scanning length resulted in about a fourfold increase in scanning velocity. A second experiment was conducted to study the influence of scanning velocity on psychophysical detection thresholds. This was done by systematically imposing specific scanning velocities to the participants while the thresholds were measured. The main result of the second experiment was that psychophysical detection thresholds are constant over a relatively broad range of scanning velocities.
Dark leaf spot (Alternaria brassicicola) on Chinese cabbage: spatial patterns
Authors: Chen L. Y. , Price T. V. , Silvapulle M. J.
Published: July 2005

The spatial spread of dark leaf spot caused by Alternaria brassicicola on Chinese cabbage was characterised over 2 years. The study was conducted in 2 field trials using ordinary runs, mapping, spatial autocorrelation, and 2-dimensional distance class analyses. Diseased plants were generally clustered and cluster orientation coincided with the line of inoculation. Disease spread was greater within than across rows. The maximum number of spatial lags with significantly positive autocorrelations occurred when disease incidence levels reached 20–80% in summer 1993–94. Core cluster size generally increased with disease incidence. Two-dimensional distance class analysis was the best analytical method among those used in describing spatial spread of the disease as it did not only provide maximum information but also considered missing data.
Environmental responsiveness of fibre diameter in grazing fine wool Merino sheep
Authors: Brown D. J. , Crook B. J.
Published: July 2005

Fibre diameter, fibre length, and the ratio of fibre length growth to mean fibre diameter (L/D), fibre diameter profile characteristics, and staple strength were examined in 16 fine wool Merino wethers in a 12-month field experiment. Variations in fibre diameter, fibre length, and L/D were shown to be associated with fibre diameter profile characteristics and staple strength. At constant fibre diameter, L/D was significantly positively related to variation in fibre diameter along the staple. A positive correlation between seasonal variation in L/D and variation in diameter between fibres was also observed. Staple length was significantly positively correlated with along-staple variation in fibre diameter and negatively correlated with variation in fibre diameter among fibres. Among-fibre variation in fibre diameter was not significantly correlated with along-staple variation in fibre diameter. Seasonal variation in fibre length growth, fibre diameter, and the ratio of length to diameter throughout the year was associated with increased variation in fibre diameter along the fibre diameter profile and reduced staple strength in grazing sheep. Seasonal variation in fibre diameter was mostly related to mean fibre diameter, L/D, and seasonal variation in fibre length growth rate. Changes in fibre diameter throughout the year were also related to seasonal changes in body weight, fat depth, and skin thickness.
Evaluation of phalaris (Phalaris aquatica L.) germplasm for persistence under grazing on the North-West Slopes, New South Wales
Authors: Culvenor R. A. , Boschma S. P.
Published: July 2005

The survival of available cultivars of introduced temperate perennial grasses has been less than adequate under grazing on the North-West Slopes of New South Wales. A wide range of germplasm of the Mediterranean perennial grass, phalaris (Phalaris aquatica L.), was assessed for persistence, seedling vigour, winter yield potential, time of reproductive development, and summer dormancy in grazed swards at 3 sites (Manilla, Tamworth, Purlewaugh) from 1998 to 2001. The aim was to understand population characteristics that influence persistence in this environment and to identify persistent populations.
Good establishment was achieved after above-average winter–spring rainfall in 1998. Persistence was high during the first year of grazing (1999) but declined under lower rainfall during 2000 at the Manilla and Tamworth sites. By 2001, a wide range in persistence had developed at these 2 sites. A group of wild populations, mainly from North Africa, was identified as being more persistent at both sites than any available cultivar. Two early cultivars, Sirocco and CPI 19305, were also relatively persistent. None of the germplasm survived a subsequent severe drought in 2002 at Manilla and Tamworth. Persistence remained high despite higher grazing pressure at the Purlewaugh site until the 2002 drought year, when changes in survival correlated with those at the other sites occurred.
Biplot analysis indicated that early reproductive development and high summer dormancy were associated with persistence in both wild and bred populations. High seedling and winter growth potential was less strongly associated with persistence. Wild and bred germplasm from North Africa displayed these characteristics to a marked extent, whereas germplasm from southern Europe and Sardinia did not and was less persistent. A group of wild populations mainly from Morocco was identified as the basis for cultivar development.
Trehalose 6-phosphate regulates starch synthesis via posttranslational redox activation of ADP-glucose pyrophosphorylase
Authors: Kolbe Anna , Tiessen Axel , Schluepmann Henriette , Paul Matthew , Ulrich Silke , Geigenberger Peter
Published: July 2005

Trehalose is the most widespread disaccharide in nature, occurring in bacteria, fungi, insects, and plants. Its precursor, trehalose 6-phosphate (T6P), is also indispensable for the regulation of sugar utilization and growth, but the sites of action are largely unresolved. Here we use genetic and biochemical approaches to investigate whether T6P acts to regulate starch synthesis in plastids of higher plants. Feeding of trehalose to
Arabidopsis
leaves led to stimulation of starch synthesis within 30 min, accompanied by activation of ADP-glucose pyrophosphorylase (AGPase) via posttranslational redox modification. The response resembled sucrose but not glucose feeding and depended on the expression of SNF1-related kinase. We also analyzed transgenic
Arabidopsis
plants with T6P levels increased by expression of T6P synthase or decreased by expression of T6P phosphatase (TPP) in the cytosol. Compared with wild type, leaves of T6P synthase-expressing plants had increased redox activation of AGPase and increased starch, whereas TPP-expressing plants showed the opposite. Moreover, TPP expression prevented the increase in AGPase activation in response to sucrose or trehalose feeding. Incubation of intact isolated chloroplasts with 100 μM T6P significantly and specifically increased reductive activation of AGPase within 15 min. Results provide evidence that T6P is synthesized in the cytosol and acts on plastidial metabolism by promoting thioredoxin-mediated redox transfer to AGPase in response to cytosolic sugar levels, thereby allowing starch synthesis to be regulated independently of light. The discovery informs about the evolution of plant metabolism and how chloroplasts of prokaryotic origin use an intermediate of the ancient trehalose pathway to report the metabolic status of the cytosol.
Functional conformational motions in the turnover cycle of cholesterol oxidase
Authors: Lerch Hans-Philipp , Rigler Rudolf , Mikhailov Alexander S.
Published: July 2005

Reexamining experimental data of single-molecule fluorescence correlation spectroscopy for cholesterol oxidase, we find that the existing Michaelis–Menten models with dynamical disorder cannot explain strong correlations between subsequent turnover cycles revealed in the diagonal feature in the joint statistical distribution of adjacent “on” times of this enzyme. We suggest that functional conformational motions representing ordered sequences of transitions between a set of conformational substates are involved, along with equilibrium conformational fluctuations in the turnover cycle of cholesterol oxidase. A two-channel model of single-enzyme dynamics, including a slow functional conformational motion in one of the channels, is proposed that allows us to reproduce such strong correlations.
Why the Gene Will Not Return*
Authors: Lloyd Elisabeth A.
Published: July 2005

I argue that four of the fundamental claims of those calling themselves ‘genic pluralists’—Philip Kitcher, Kim Sterelny, and Ken Waters—are defective. First, they claim that once genic selectionism is recognized, the units of selection problems will be dissolved. Second, Sterelny and Kitcher claim that there are no targets of selection (interactors). Third, Sterelny, Kitcher, and Waters claim that they have a concept of genic causation that allows them to give independent genic causal accounts of all selection processes. I argue that each one of these claims is either false or misleading. Moreover, the challenge that arises from the availability of genic causal accounts, namely, the inability to choose on rational grounds among genic and higher-level accounts, is unsupported.
Why Genic and Multilevel Selection Theories Are Here to Stay*
Authors: Waters C. Kenneth
Published: July 2005

I clarify the difference between pluralist and monist interpretations of levels of selection disputes. Lloyd has challenged my claim that a plurality of models correctly accounts for situations such as maintenance of the sickle-cell trait, and I revisit this example to show that competing theories don't disagree about the existence of ‘high-level’ or ‘low-level’ causes; rather, they parse these causes differently. Applying Woodward's theory of causation, I analyze Sober's distinction between ‘selection of’ versus ‘selection for’. My analysis shows that this distinction separates true causes from pseudocauses, but it also reveals that the distinction is irrelevant to the levels debate; it makes no sense to say true causes are at higher levels and not lower levels. The levels debate is not about separating real causes from pseudocauses; it's about finding useful ways to parse and disentangle causes.
Radical Probabilism and Bayesian Conditioning*
Authors: Bradley Richard
Published: July 2005

Richard Jeffrey espoused an antifoundationalist variant of Bayesian thinking that he termed ‘Radical Probabilism’. Radical Probabilism denies both the existence of an ideal, unbiased starting point for our attempts to learn about the world and the dogma of classical Bayesianism that the only justified change of belief is one based on the learning of certainties. Probabilistic judgment is basic and irreducible. Bayesian conditioning is appropriate when interaction with the environment yields new certainty of belief in some proposition but leaves one's conditional beliefs untouched (the ‘Rigidity’ condition). Although Richard Jeffrey denied the general applicability of this condition, one of his main contributions to probabilistic thinking is a form of belief updating—now typically called ‘Jeffrey conditioning’ or ‘probability kinematics’—that is appropriate in circumstances in which Rigidity is satisfied, but where the interaction causes one to reevaluate one's probability judgments over some partition of the possibility space without conferring certainty on any particular element. The most familiar occasion for Jeffrey conditioning is receipt of uncertain evidence: things partially perceived or remembered. But it also serves to illuminate belief updating occasioned by a change in one's degrees of conditional belief, a kind of belief change largely ignored by classical Bayesianism. I argue that such changes in conditional belief can also be basic (in the sense of not being analyzable as a consequence of conditioning on factual information) and offer a kinematical model for a particular kind change in conditional belief. Both are applied to changes in preference. Finally, I argue that Rigidity can fail when changes of belief give inferential grounds for changes in conditional belief (and vice versa). These failures show that conditioning methods are properly regarded, not as valid rules of inference, but as tools in the ‘art of judgment’.
The Structure of Scientific Theory Change: Models versus Privileged Formulations*
Authors: Mattingly James
Published: July 2005

Two views of scientific theories dominated the philosophy of science during the twentieth century, the syntactic view of the logical empiricists and the semantic view of their successors. I show that neither view is adequate to provide a proper understanding of the connections that exist between theories at different times. I outline a new approach, a hybrid of the two, that provides the right structural connection between earlier and later theories, and that takes due account of the importance of the mathematical models of a theory (the semantic component) and of the various distinct formulations that pick out these models (the syntactic component).
Extraction of regulatory gene/protein networks from Medline
Authors: Šarić Jasmin , Jensen Lars Juhl , Ouzounova Rossitza , Rojas Isabel , Bork Peer
Published: July 2005

Motivation: We have previously developed a rule-based approach for extracting information on the regulation of gene expression in yeast. The biomedical literature, however, contains information on several other equally important regulatory mechanisms, in particular phosphorylation, which we now expanded for our rule-based system also to extract.

Results: This paper presents new results for extraction of relational information from biomedical text. We have improved our system, STRING-IE, to capture both new types of linguistic constructs as well as new types of biological information [i.e. (de-)phosphorylation]. The precision remains stable with a slight increase in recall. From almost one million PubMed abstracts related to four model organisms, we manage to extract regulatory networks and binary phosphorylations comprising 3319 relation chunks. The accuracy is 83–90% and 86–95% for gene expression and (de-)phosphorylation relations, respectively. To achieve this, we made use of an organism-specific resource of gene/protein names considerably larger than those used in most other biology related information extraction approaches. These names were included in the lexicon when retraining the part-of-speech (POS) tagger on the GENIA corpus. For the domain in question, an accuracy of 96.4% was attained on POS tags. It should be noted that the rules were developed for yeast and successfully applied to both abstracts and full-text articles related to other organisms with comparable accuracy.

Availability: The revised GENIA corpus, the POS tagger, the extraction rules and the full sets of extracted relations are available from

Contact:  saric@eml-r.org
The osteoprotective effect of Herba epimedii (HEP) extract in vivo and in vitro
Authors: Xie Fang , Wu Chun-Fu , Lai Wan-Ping , Yang Xu-juan , Cheung Pik-Yuan , Yao Xin-Sheng , Leung Ping-Chung , Wong Man-Sau
Published: July 2005

Herba epimedii (HEP) is one of the most frequently used herbs prescribed for treatment of osteoporosis in China. In the present study, the in vivo effects of HEP extract on bone metabolism were evaluated using 4‐month‐old ovariectomized (OVX) or sham‐operated (Sham) female Sprague‐Dawley rats orally administered with HEP extract (110 mg kg−1d−1), 17ß‐estrogen (2 mg kg−1d−1) or its vehicle for 3 months. HEP extract significantly decreased urinary calcium excretion, suppressed serum alkaline phosphatase (ALP) activity and urinary deoxypyridinoline levels in OVX rats (P < 0.05 versus vehicle‐treated OVX rats). Histomorphometric analysis indicated that HEP extract could prevent OVX‐induced bone loss by increasing tibial trabecular bone area and decreasing trabecular separation in OVX rats (P < 0.05 versus vehicle‐treated OVX group). The in vitro effects of HEP extract were also studied using rat osteoblast‐like UMR 106 cells. HEP extract significantly stimulated cell proliferation in a dose‐dependent manner (P < 0.01 versus vehicle‐treated) and increased ALP activity at 200 μgml−1 (P < 0.01 versus vehicle‐treated) in UMR 106 cells. It modulated osteoclastogenesis by increasing osteoprotegrin (OPG) mRNA and decreasing receptor activator of NF‐κB ligand (RANKL) mRNA expression, resulting in a dose‐dependent increase in OPG/RANKL mRNA ratio (P < 0.01 versus vehicle‐treated). Taken together, HEP treatment can effectively suppress the OVX‐induced increase in bone turnover possibly by both an increase in osteoblastic activities and a decrease in osteoclastogenesis. The present study provides the evidence that HEP can be considered as a complementary and alternative medicine for treatment of post‐menopausal osteoporosis.
Cisplatin Nephrotoxicity and Protection by Milk Thistle Extract in Rats
Authors: Karimi Gholamreza , Ramezani Mohammad , Tahoonian Zahra
Published: July 2005

The protective effect of methanolic extract of milk thistle seeds and silymarin against cisplatin‐induced renal toxicity in male rats after a single intraperitoneal injection of 3 mg kg−1 cisplatin were studied. Over 5 days, cisplatin‐treated rats showed tubular necrosis and elevation in blood urea nitrogen (BUN) and serum creatinine (Scr). Pretreatment of animals with silymarin (50 mg kg−1) or extract (0.6 g kg−1) 2 h before cisplatin prevented the tubular damage. Rats treated with silymarin or extract 2 h after cisplatin had BUN and Scr significantly lower than those receiving cisplatin, but mild to moderate necrosis was observed. These results suggested that milk thistle may protect against cisplatin‐induced renal toxicity and might serve as a novel combination agent with cisplatin to limit renal injury.
Blood‐nourishing and Hard‐softening Capsule Costs Less in the Management of Osteoarthritic Knee Pain: A Randomized Controlled Trial
Authors: Cao Yuelong , Shi Yinyu , Zheng Yuxing , Shi Meiyu , Lo Sing Kai
Published: July 2005

The blood‐nourishing and hard‐softening (BNHS) capsule is a traditional Chinese formula used in the symptomatic treatment of inflammation and pain. We conducted this randomized controlled trial to compare the efficacy of BNHS with other commonly prescribed drugs. We recruited 120 patients from two teaching hospitals; 30 patients in each hospital were randomly assigned to receive BNH In one hospital, the 30 controls were given another traditional Chinese drug; whereas a Western medicine (chondroprotection drug/Viartril‐s) was used as the control in the other hospital. Intervention was carried out over a period of 4 weeks. Primary outcome measures included self‐reported pain level, and changes in stiffness and functional ability as measured by the Western Ontario McMaster Universities Osteoarthritis (WOMAC) index. Mixed models were used for statistical analysis. Substantial improvements in disease‐specific symptoms were observed, after 4 weeks of treatment, in patients taking BNHS capsules. As assessed by the WOMAC index, pain level of the BNHS group decreased by 57% [95% confidence interval (CI) = 50, 63], stiffness by 63% (95% CI = 55, 71) and functional ability increased by 56% (95% CI = 50, 63). No significant differences were found in any of the outcome measures between the BNHS group and either of the comparison groups. No severe adverse effects were reported. However, this study lacked a placebo group; therefore, we conclude that BNHS appears to be as effective as commonly prescribed medicines for the relief of pain and dysfunction in knee osteoarthritis patients, but costs a lot less than other Western and herbal drugs in the study.
Multilevel Analyses of Comparative Data: A Comment
Authors: Beck Nathaniel
Published: July 2005

The articles in this special issue all use multilevel methods to study comparative political behavior. This is obviously a good thing, for both methodology and comparative politics. Clearly comparative politics means comparing things and not just studying nations other than the United States. This is equally true of micropolitical studies. These articles all do a very nice job of showing how one can do comparative micropolitics (and tie together micro and macro variables).
Nontechnical Skills in Anesthesia Crisis Management with Repeated Exposure to Simulation-based Education
Authors: Yee Bevan , Naik Viren N. , Joo Hwan S. , Savoldelli Georges L. , Chung David Y. , Houston Patricia L. , Karatzoglou Bruce J. , Hamstra Stanley J.
Published: July 2005

Background

Critical incident reporting and observational studies have identified nontechnical skills that are vital to successful anesthesia crisis management. Examples of such skills include task management, team working, situation awareness, and decision making. These skills are not necessarily acquired through clinical experience and may need to be specifically taught. This study uses a high-fidelity patient simulator to assess the effect of repeated exposure to simulated anesthesia crises on the nontechnical skills of anesthesia residents.

Methods

After institutional research board approval and informed consent, 20 anesthesia residents were recruited. Each resident was randomized to participate as the primary anesthesiologist in the management of three different simulated anesthesia crises using a high-fidelity patient simulator. After each session, videotaped footage was used to facilitate debriefing of their nontechnical skills. The videotapes were later reviewed by two expert blinded independent assessors who rated each resident's nontechnical skills by using a previously validated and reliable marking system.

Results

: A significant improvement in the nontechnical skills of residents was demonstrated from their first to second session and from their first to third session (both P < 0.005). However from their second to third session, no significant improvement was observed. Interrater reliability between assessors was modest (single rater intraclass correlation = 0.53).

Conclusion

A single exposure to anesthesia crises using a high-fidelity patient simulator can improve the nontechnical skills of anesthesia residents. However, an additional simulation session may confer little or no additional benefit.
Fentanyl Attenuates α1B-Adrenoceptor–Mediated Pulmonary Artery Contraction
Authors: Sohn Ju-Tae , Ding Xueqin , McCune Daniel F. , Perez Dianne M. , Murray Paul A.
Published: July 2005

Background

The authors tested the hypothesis that the intravenous anesthetic fentanyl would attenuate the pulmonary vasoconstrictor response to alpha1-adrenoceptor activation. They also investigated the alpha1-adrenoceptor subtypes that could potentially mediate this effect of fentanyl.

Methods

Endothelium-denuded canine pulmonary arterial rings were suspended for isometric tension recording. Dose-response curves for the alpha1-adrenoceptor agonist phenylephrine were generated in the absence and presence of fentanyl. The effects of inhibiting alpha2 (rauwolscine), alpha1 (prazosin), alpha1A (5-methylurapidil), alpha1B (chloroethylclonidine), and alpha1D (BMY 7378) adrenoceptors on phenylephrine contraction were also investigated. Receptor "protection" studies were performed to investigate the specific role of alpha1B adrenoceptors in mediating fentanyl-induced changes in phenylephrine contraction. Finally, competition binding studies were performed in rat-1 fibroblasts stably transfected with human alpha1-adrenoceptor complementary DNAs corresponding to the alpha1A-, alpha1B-, or alpha1D-adrenoceptor subtypes to directly assess whether fentanyl can compete for the alpha1-adrenoceptor activation pocket.

Results

Fentanyl attenuated phenylephrine contraction in a dose-dependent fashion. Rauwolscine had no effect on phenylephrine contraction. Phenylephrine contraction was inhibited by prazosin and abolished by chloroethylclonidine but was relatively resistant to inhibition by 5-methylurapidil and BMY 7378. Pretreatment with fentanyl before exposure to chloroethylclonidine increased the maximal contractile response to phenylephrine compared to chloroethylclonidine pretreatment alone. Competition binding studies revealed that fentanyl binds to all three alpha1-adrenoceptor subtypes, with a fivefold greater affinity for the alpha1B-adrenoceptor compared with the alpha1D-adrenoceptor subtype.

Conclusion

Phenylephrine-induced contraction is primarily mediated by alpha1B-adrenoceptor activation in canine pulmonary artery. Fentanyl attenuates phenylephrine contraction by binding to alpha1B adrenoceptors.
A Physiologically Based, Recirculatory Model of the Kinetics and Dynamics of Propofol in Man
Authors: Upton Richard N. , Ludbrook Guy
Published: July 2005

Background

The disposition of propofol in man is commonly described using a three-compartment mamillary model. However, these models do not incorporate blood flows as parameters. This complicates the representation of the changes in blood flows that may occur in surgical patients. In contrast, complex physiologically based models are derived from data sets (e.g., tissue:blood partition coefficients) that may not be readily collected in man.

Methods

Alternatively, the authors report a recirculatory model of propofol disposition in a "standard" man that incorporates detailed descriptions of the lungs and brain, but with a lumped description of the remainder of the body. The model was parameterized from data in the literature using a "meta-modeling" approach. The first-pass passage of propofol through the venous vasculature and the lungs was a function of the injected drug mixing with cardiac output and passing through a three-"tank in series" model for the lungs. The brain was represented as a two-compartment model defined by cerebral blood flow and a permeability term. The Bispectral Index was a linear function of the mean brain concentration. The remainder of the body was represented by compartment systems for the liver, fast distribution and slow distribution.

Results

The model was a good fit of the data and was able to predict other data not used in the development of the model.

Conclusions

The model may ultimately find a role in improving the fidelity of patient simulators currently used to train anesthetists and for clinical practice simulation to optimize dosing and management strategies.
Ketamine Inhibits Inspiratory-evoked γ-Aminobutyric Acid and Glycine Neurotransmission to Cardiac Vagal Neurons in the Nucleus Ambiguus
Authors: Wang Xin , Huang Zheng-Gui , Dergacheva Olga , Bouairi Evguenia , Gorini Christopher , Stephens Christopher , Andresen Michael C. , Mendelowitz David
Published: July 2005

Background

Ketamine can be used for perioperative pain management as well as a dissociative anesthetic agent in emergency situations. However, ketamine can induce both cardiovascular and respiratory depression, especially in pediatric patients. Although ketamine has usually been regarded as sympathoexcitatory, recent work has demonstrated that ketamine has important actions on parasympathetic cardiac vagal efferent activity. The current study tests the hypothesis that ketamine, at clinical relevant concentrations, alters central cardiorespiratory interactions in the brainstem and, in particular, the inspiration-evoked increase in gamma-aminobutyric acid-mediated and glycinergic neurotransmission to parasympathetic cardiac efferent neurons.

Methods

Cardiac vagal neurons were identified by the presence of a retrograde fluorescent tracer. Respiratory evoked gamma-aminobutyric acid-mediated and glycinergic synaptic currents were recorded in cardiac vagal neurons using whole cell patch clamp techniques while spontaneous rhythmic respiratory activity was recorded simultaneously.

Results

: Ketamine, at concentrations from 0.1 to 10 microM, evoked a concentration-dependent inhibition of inspiratory burst frequency. Inspiration-evoked gamma-aminobutyric acid-mediated neurotransmission to cardiac vagal neurons was inhibited at ketamine concentrations of 0.5 and 1 microM. The increase in glycinergic activity to cardiac vagal neurons during inspiration was also inhibited at ketamine concentrations of 0.5 and 1 microM.

Conclusions

At clinically relevant concentrations (0.5 and 1 microM), ketamine alters central respiratory activity and diminishes both inspiration-evoked gamma-aminobutyric acid-mediated and glycinergic neurotransmission to parasympathetic cardiac efferent neurons. This reduction in inhibitory neurotransmission to cardiac vagal neurons is likely responsible for the compromised respiratory sinus arrhythmia that occurs with ketamine anesthesia.
Evidence against Trigger Point Injection Technique for the Treatment of Cervicothoracic Myofascial Pain with Botulinum Toxin Type A
Authors: Ferrante F Michael , Bearn Lisa , Rothrock Robert , King Laurence
Published: July 2005

Background

Traditional strategies for myofascial pain relief provide transient, incomplete, variable, or unpredictable outcomes. Botulinum toxin is itself an analgesic but can also cause sustained muscular relaxation, thereby possibly affording even greater relief than traditional therapies.

Methods

The study goal was to determine whether direct injection of botulinum toxin type A (BoNT-A) into trigger points was efficacious for cervicothoracic myofascial pain, and if so, to determine the presence or absence of a dose-response relation. One hundred thirty-two patients with cervical or shoulder myofascial pain or both and active trigger points were enrolled in a 12-week, randomized, double-blind, placebo-controlled trial. After a 2-week washout period for all medications, patients were injected with either saline or 10, 25, or 50 U BoNT-A into up to five active trigger points. The maximum doses in each experimental group were 0, 50, 125, and 250 U per patient, respectively. Patients subsequently received myofascial release physical therapy and amitriptyline, ibuprofen, and propoxyphene-acetaminophen napsylate. Follow-up visits occurred at 1, 2, 4, 6, 8, and 12 weeks. Outcome measures included visual analog pain scores, pain threshold as measured by pressure algometry, and rescue dose use of propoxyphene-acetaminophen napsylate.

Results

No significant differences occurred between placebo and BoNT-A groups with respect to visual analog pain scores, pressure algometry, and rescue medication.

Conclusions

Injection of BoNT-A directly into trigger points did not improve cervicothoracic myofascial pain. The role of direct injection of trigger points with BoNT-A is discussed in comparison to other injection methodologies in the potential genesis of pain relief.
Use of Anesthesia Induction Rooms Can Increase the Number of Urgent Orthopedic Cases Completed within 7 Hours
Authors: Torkki Paulus M. , Marjamaa Riitta A. , Torkki Markus I. , Kallio Pentti E. , Kirvelä Olli A.
Published: July 2005

Background

Mean turnover times and the time spent in the operating room (OR) can be reduced by concurrent induction of anesthesia. Previous studies of anesthesia induction outside the OR have concentrated either on anesthesia-controlled time or turnover time. The goal of this study was to investigate the impact of an induction room model on the whole surgical process, its phases and delays between the phases, and the number of cases performed during the 7-h working day.

Methods

A prospective analysis of OR times was conducted for 5 weeks with the traditional induction-in-the-OR model followed by 4 weeks with a new model: A team of two nurses and one anesthesiologist was added to one OR to perform parallel anesthesia induction in a separate induction room. The durations of phases of surgical process, number of completed cases between 7:45 am and 3:00 pm, and daily raw utilization of the OR were assessed. Results were compared to those measured before the intervention.

Results

The mean nonoperative time was reduced by 45.6%, whereas surgery time remained unchanged. The time savings contributed to the concurrent anesthesia induction and the cut down in delays between the phases. The new model allowed one additional case to be performed during the 7-h working day.

Conclusions

Anesthesia induction outside the OR can increase the number of surgical cases performed during a regular workday.
Breath Hydrogen Test After a Bean Meal Demonstrates Delayed Oro‐Cecal Transit Time in Children with Chronic Constipation
Authors: Soares Ana Cristina Fontenele , Lederman Henrique Manoel , Fagundes‐Neto Ulysses , de Morais Mauro Batista
Published: July 2005

Objective:

To evaluate oro‐cecal transit time in children with chronic constipation.

Methods:

34 patients with chronic functional constipation age 3 to 13 years and 15 controls without constipation. Oro‐cecal transit time was evaluated using the hydrogen breath test after ingestion of lactulose and after a standard meal of cooked beans. Total and segmental colonic transit times were measured with radiopaque markers.

Results:

Of 34 patients with chronic constipation 61.8% had increased total colonic transit time (>62 hours). Oro‐cecal transit time measured with lactulose as substrate was similar (p = 0.727) in constipated patients with increased colonic transit time (63.8 ± 16.3 minutes), in constipated patients with normal colonic transit time (66.9 ± 22.9 minutes), and in controls (65.3 ± 15.5 minutes). Using a test meal of beans, the hydrogen breath test showed that oro‐cecal transit time of constipated patients with increased total colon transit time was higher (252.4 ± 23.2 minutes) than oro‐cecal transit time of constipated patients with normal colonic transit time (227.7 ± 39.6 minutes) or controls (205.3 ± 23.3 minutes) (p < .05).

Conclusion:

Hydrogen excretion in breath after a bean test meal showed delayed oro‐cecal transit time in children with chronic constipation with abnormal total colonic transit time.