bluuebunny/crossref_metadata_2025 huggingface dataset:
Lost to follow‐up in high level evidence‐based studies related to the surgical management of lower urinary tract symptoms secondary to benign prostatic enlargement: Does it matter?
Authors: Ou Rubiao , Zimmern P.
Published: August 2011

Aims

A contemporary review of the literature on benign prostatic hyperplasia (BPH) for lost to follow‐up (LTF) rate was performed to evaluate the significance of LTF in the surgical management of lower urinary tract symptoms (LUTS) secondary to benign prostatic enlargement (BPE).

Methods

Randomized clinical trials (RCT level I) on the surgical treatment of LUTS secondary to BPE, with at least 12‐month follow‐up, from 1/1995 to 10/2010 were searched on PUBMED. Data reviewed included types of study, number of participating centers or hospitals, sample size calculation, surgical techniques, power calculation, estimated dropout rate, duration of follow‐up, rate and reasons for LTF.

Results

Forty‐eight RCT articles were identified. Eleven articles gave details on sample size calculation, and 13 explained their LTF rate after reaching LTF patients by mail or telephone. Percentages of LTF patients were 12% (492/4202) at 12 months in 39 articles, 21% (398/1891) at 24 months in 16 articles, 33% (485/1479) at 36 months in 11 articles, 41% (283/694) at 48 months in 6 articles, and 56% (409/729) at ≥60 months in 6 articles. Fifteen articles reported no missing data, mostly because of small sample size or short follow‐up. Only 7 articles defined LTF patients as treatment failure and reported outcomes accordingly.

Conclusions

The increase in LTF rate over time compromises the strength of the conclusions from the leftover patient population. Only 15% of RCTs adhered to the CONSORT statement by considering their LTF patients as treatment failures. Neurourol. Urodynam. 30: 1416–1421, 2011. © 2011 Wiley Periodicals, Inc.
Systemic administration of fluorogold for anatomical pre‐labeling of autonomic and motor neurons in the rat spinal cord compromises urodynamic recordings in acute but not long‐term studies
Authors: Chang Huiyi H. , Havton Leif A.
Published: August 2011

Aims

The use of anatomical tracer injections into peripheral tissues for retrograde labeling of spinal cord neurons may compromise physiological experiments in combined functional and morphological studies.

Methods

We investigated whether a systemic injection of a retrogradely transported tracer, fluorogold (FG), may provide an alternative to direct injections into end organs for combined anatomical and physiological studies of the lower urinary tract. Urodynamic studies including cystometrogram recordings and external urethral sphincter electromyography were used as functional outcome measures.

Results

Pre‐labeling of spinal cord neurons by intraperitoneal (i.p.) administration of FG resulted in a transient decrease in voiding efficiency, increase in resting pressure as well as increase in bladder size and weight at 5–7 days after the tracer administration. In contrast, there were no urodynamic or end‐organ effects detected at 6–8 weeks after the i.p. injection of FG.

Conclusions

We suggest that pre‐labeling of spinal autonomic and motor neurons using i.p. administration of FG may be a useful tool when combining anatomical and functional outcome measures in long‐term but not acute studies. Neurourol. Urodynam. 31:162–167, 2012. © 2011 Wiley Periodicals, Inc.
Patient reported incontinence after radical prostatectomy is more common than expected and not associated with the nerve sparing technique: Results from the center for prostate disease research (CPDR) database
Authors: Peterson Andrew C. , Chen Yongmei
Published: August 2011

Aims

The reported incidence of urinary incontinence (UI) after radical prostatectomy (RP) ranges from 2.5 to 87%. We reviewed data from the Center for Prostate Disease Research (CPDR) to determine the incidence of patient reported UI after RP (postRPUI) and establish risk factors for postRPUI.

Methods

We obtained IRB approval to query the CPDR database on all patients undergoing RP between 1990 and 2007. We assessed patient age, nerve sparing status, blood loss, margin status, stage, and patient self‐reported incontinence status as entered into the database. Patients were counted as having UI only if the database showed patient reported UI in every follow‐up encounter. Patients were counted as permanently dry if at any time in the follow‐up they answered that they had no UI.

Results

Four thousand three hundred seventy four patients underwent RP without radiation therapy or hormonal ablation between 1990 and 2007. Complete data were available for 1,616 (37%) and 1,459 (90.3%) reported UI more than 1 year after RP with a median follow‐up of 50.7 months. Older age is an independent risk factor for UI (OR = 1.021, P ≤ 0.0003). Nerve sparing, blood loss, stage of cancer, and margin status were not predictive for UI.

Conclusions

Our data indicate that patient reported post‐RPUI is higher than expected but is not related to the nerve sparing technique, stage of cancer nor blood loss at the time of surgery. Neurourol. Urodynam. 31:60–63, 2012. © 2011 Wiley Periodicals, Inc.
Overactive bladder in Taiwanese women: Re‐analysis of epidemiological database of community from 1999 to 2001
Authors: Chen Y.C. , Ng S.C. , Chen S.L. , Huang Y.H. , Hu S.W. , Chen G.D.
Published: August 2011

Aims

To update our previous computerized epidemiological data according to the new taxonomy, we re‐evaluated and re‐analyzed the data using the current definitions of lower urinary tract symptoms (LUTS) which were approved and published by the ICS in 2002 and 2010 according to patient perception. Further, we divided overactive bladder (OAB) symptoms into OAB dry and OAB wet to assess their prevalence percentages by using the current definitions.

Methods

OAB syndrome in our computerized database was re‐defined as having the following storage symptoms present, that is, frequency, urgency, nocturia, urgency incontinence, or stress urinary incontinence (SUI). The prevalence of OAB syndrome was determined with a different taxonomy for those five storage symptoms either singly or in combination. OAB symptoms which were probably associated with mixed incontinence were either ignored or excluded.

Results

The prevalence of OAB syndrome varied from 34.76% to 28.33% to 20.95% using different classifications of the above five storage symptoms. The prevalence of OAB wet symptoms increased with advancing age and this finding was consistent with three different definitions.

Conclusions

The prevalence of OAB using the current definition is slightly higher than the result found in our previous published data using a defective classification system of OAB symptoms. The effects of mixed symptoms and probable misclassification cannot be overlooked because many women with OAB (with or without urgency incontinence) might also have SUI. Neurourol. Urodynam. 31:56–59, 2012. © 2011 Wiley Periodicals, Inc.
A topological optimization approach for structural design of a high‐speed low‐load mechanism using the equivalent static loads method
Authors: Yang Zhi‐Jun , Chen Xin , Kelly Robert
Published: August 2011

In high‐speed low‐load mechanisms, the principal loads are the inertial forces caused by the high accelerations and velocities. Hence, mechanical design should consider lightweight structures to minimize such loads. In this paper, a topological optimization method is presented on the basis of the equivalent static loads method. Finite element (FE) models of the mechanism in different positions are constructed, and the equivalent loads are obtained using flexible multibody dynamics simulation. Kinetic DOFs are used to simulate the motion joints, and a quasi‐static analysis is performed to obtain the structural responses. The element sensitivity is calculated according to the static‐load‐equivalent equilibrium, in such a way that the influence on the inertial force is considered. A dimensionless component sensitivity factor (strain energy caused by unit load divided by kinetic energy from unit velocity) is used, which quantifies the significance of each element. Finally, the topological optimization approach is presented on the basis of the evolutionary structural optimization method, where the objective is to find the maximum ratio of strain energy to kinetic energy. In order to show the efficiency of the presented method, we presented two numerical cases. The results of these analyses show that the presented method is more efficient and can be easily implemented in commercial FE analysis software. Copyright © 2011 John Wiley & Sons, Ltd.
A numerical scheme for the one‐dimensional pressureless gases system
Authors: Boudin Laurent , Mathiaud Julien
Published: August 2011

In this work, we investigate the numerical approximation of the one‐dimensional pressureless gases system. After briefly recalling the mathematical framework of the duality solutions introduced by Bouchut and James (Comm. Partial Differential Equations 24 (1999), 2173–2189), we point out that the upwind scheme for density and momentum does not satisfy the one‐sided Lipschitz (OSL) condition on the expansion rate required for the duality solutions. Then we build a diffusive scheme which allows the OSL condition to be recovered by following the strategy described by Boudin (SIAM J Math Anal 32 (2000), 172–193) for the continuous model. © 2011 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2011
Evidence of Trephinations among the Garamantes, a Late Holocene Saharan Population
Authors: Nikita E. , Lahr M. M. , Mattingly D.
Published: August 2011

The current communication examines three male individuals who belonged to the Garamantian civilisation, Fezzan, Libya. The individuals have been dated to ad 1–700 and exhibit signs of perforations on their crania, which appear to represent trephinations. The sophistication of the practice and its successful execution, as evidenced by traces of healing, indicate that the Garamantes possessed the knowledge of complex surgical procedures. Copyright © 2011 John Wiley & Sons, Ltd.
Rate dependencies and energy absorption characteristics of nanoreinforced, biofiber, and microcellular polymer composites
Authors: Argento Alan , Kim Wonsuk , Lee Ellen C. , Harris Angela M. , Mielewski Deborah F.
Published: August 2011

The effects of loading rate on bio‐, nano‐, and microcellular composite systems have been studied. Fiber–resin systems have been manufactured and dynamically tested at various speeds to assess their strain‐rate dependencies (rate hardening) and energy‐dissipation characteristics compared to conventional materials. The following composite systems have been fabricated and studied: polypropylene/sisal fiber biocomposite, hemp/vinyl ester biocomposite, thermoplastic olefin/nanoclay composite, microcellular polypropylene/sisal fiber biocomposite, and microcellular thermoplastic olefin/nanoclay composite. It has been determined that the biocomposite systems studied possess unique energy dissipation characteristics and muted rate dependence, while the nanocomposite system did not. In addition, microcellular foaming of these materials further enhanced the effects. Though the exact mechanisms at play are not fully understood at this point, it has been found that in addition to the microcellular voids, the anatomical vasculature of the natural fibers may play a role in energy dissipation processes in these hybrid materials. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers
Electron reflector to enhance photovoltaic efficiency: application to thin‐film CdTe solar cells
Authors: Hsiao Kuo‐Jui , Sites James R.
Published: August 2011

The incorporation of an electron reflector is a proposed strategy to improve the open‐circuit voltage of CdTe solar cells. An electron reflector is a conduction‐band barrier that can effectively reduce electron recombination at the back surface. In this work, the electron‐reflector strategy is numerically applied to a thin‐film CdTe record‐cell baseline model (efficiency = 16.5%). Simulation shows that to have the optimal effect from an electron reflector, the CdTe thickness should be on the order of 1 µm, or slightly lower if the optical reflection at the back surface can be enhanced. Efficiency above 19% should be achievable with a 0.2‐eV electron reflector and currently achievable parameters (1014‐cm−3 hole density and 1‐ns lifetime). Moreover, efficiency above 20% should be possible at a 1‐µm absorber layer if large optical back reflection can also be achieved. Copyright © 2011 John Wiley & Sons, Ltd.
Care pathway clustering: issues for older adult mental health services
Authors: Whelan Paul , Zoha Mo , Ramcharitar Kristal , Andrews Tresa
Published: August 2011

The imminent payment‐by‐results system for mental health in England means that Trusts need to reorganise delivery of care taking into account the new care pathway clusters. In this article, Dr Whelan and colleagues discuss the potential dilemmas and problems faced by the introduction of this system based on their own experience, with a particular focus on old age services. Copyright © 2011 Wiley Interface Ltd
Synthesis of polymeric ionic liquid microsphere/Pt nanoparticle hybrids for electrocatalytic oxidation of methanol and catalytic oxidation of benzyl alcohol
Authors: Yang Jianhu , Qiu Lihua , Liu Baoqiang , Peng Yingjing , Yan Feng , Shang Songmin
Published: August 2011

Herein, we present a facile approach for the synthesis of polymeric ionic liquids (PILs) microspheres for metal scavenging and catalysis. Crosslinked poly(1‐butyl‐3‐vinylimidazolium bromide) microspheres with the diameter of about 200 nm were synthesized via miniemulsion polymerization, in which 1,4‐di(vinylimidazolium) butane bisbromide was added as the crosslinker. Anion exchange of PIL microspheres with Pt precursor and followed by the reduction of Pt ions produced PIL microsphere supported Pt nanoparticle hybrids. The synthesized Pt nanoparticles with a diameter of about 2 nm are uniformly dispersed and strongly bound to the surface of PIL microspheres. The catalytic performances of PIL/Pt nanoparticle hybrids were evaluated for both the electrocatalytic oxidation of methanol and oxidation of benzyl alcohol. The PIL/Pt nanoparticle hybrids show better electrocatalytic activity towards the electrooxidation of methanol than pure Pt nanoparticles. Furthermore, they are effective and easily reusable catalysts for the selective oxidation of benzyl alcohol in aqueous reaction media, demonstrating that the synthesized PIL microspheres are suitable scaffolds for heterogeneous catalysts Pt. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Structure evolution of α′‐phase poly(lactic acid)
Authors: Chen Xiaolang , Kalish Jeffrey , Hsu Shaw Ling
Published: August 2011

Poly(lactic acid) films consisting of α′‐forms were prepared and uniaxially drawn. The effects of the draw rate at temperatures above the glass transition temperature on chain conformation, degree of crystallinity, and crystalline phase transformation were investigated by a combination of vibrational spectroscopy (infrared and Raman), differential scanning calorimetry, and wide‐angle X‐ray diffraction (WAXD). It was established that the α′‐crystal's phase of poly(lactic acid) films does not transform into either an α or β crystals on uniaxial drawing at a fixed draw ratio of 4. However, the degree of crystallinity was significantly increased on deformation. The structural change as a function of deformation also promotes an increase in the strain‐induced enthalpic relaxation endothermic peak appearing near the glass transition region. While the overall changes in physical properties can be attributed to the changes in the degree of crystallinity as a function of strain rate, polarized Raman spectra, and WAXD clearly illustrated changes and the differences in the amorphous and crystalline orientation as a function of processing conditions. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 49: 1446–1454, 2011
Predicting the proton conductivity of perfluorosulfonic acid membrane via combining statistical thermodynamics and molecular dynamics simulation
Authors: Kim Young Gyun , Bae Young Chan
Published: August 2011

The electrochemical properties of a perfluorosulfonic acid (PFSA) membrane are estimated using a combination of molecular dynamics simulation and statistical thermodynamic model. We obtain all parameters in an ionic conductivity model from an atomistic simulation and remove all adjusted model parameters. From a microscopic point of view, the hydrated PFSA membrane shows micro‐phase segregation which separated into hydrophilic and hydrophobic phases. Our present work originates with this phenomenon and we treat this phase segregation as if it is a continuous phase for each of which the proton (H+) is transported inside the PFSA membrane/solvent (water and alcohols) mixture. The chemical potential for a given system is estimated using a molecular simulation technique to predict the van der Waals interaction energy between the polymer and solvent. In addition, the self diffusion coefficients are calculated from the molecular dynamics simulation. We study various polymer/solvent compositions to understand the concentration dependence of self diffusion coefficient. Our self diffusion coefficients and also the predicted final ionic conductivity agree well with previously reported experimental data. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 49: 1455–1463, 2011
High‐thermally stable and high‐bandwidth graded index plastic optical fiber for vehicle networks
Authors: Asai Makoto , Yamaki Yasushi , Takahashi Satoshi , Koike Yasuhiro
Published: August 2011

Radial refractive index profiles within the graded index plastic optical fiber (GI‐POF) is formed by adding a dopant to a polymer. This addition of the dopant significantly decreased the Tg of the polymer due to the plasticization. This disadvantage made the installation of the GI‐POF difficult, especially in vehicle networks in which high thermal stability is required. We have suggested 9‐bromophenanthrene (BPT) as a novel dopant induced less plasticization for poly(methyl methacrylate) (PMMA) than the conventional dopants. However, although the fabricated GI‐POF using BPT had high enough thermal stability for vehicle networks, the attenuation was 800 dB/km and it could not be used. This high attenuation was caused by contaminant in the fabrication process of fibers. In this study, we succeeded to fabricate a GI‐POF with low‐attenuation and high‐thermal stability using highly pure BPT. Its attenuation was improved to 240 dB/km at 650 nm, which was enough transparency for vehicle networks. The Tg of the GIPOF was improved to 107 °C from 90 °C. The thermal stability of the GI‐POF below 85 °C/dry and 75 °C/85%RH was demonstrated to be as high as that of the commercially available step index POF. The bandwidth of the GI‐POF could be estimated over 4.0 GHz for the 50‐m fiber. These results demonstrated that our GI‐POF should qualify to be used in vehicle network. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 49: 1464–1469, 2011
Co‐existing paradoxical vocal cord motion and asthma in a young child
Authors: Saadoon Ammar A. , Ehlayel Mohammad
Published: August 2011

We are reporting a 7½‐year‐old child who had coexisting paradoxical vocal cord motion (PVCM) and asthma. There are only a few reported cases of PVCM in children younger than 10 years of age. Thus diagnosis mainly relies on high index of suspicion for these children. Missing PVCM diagnosis can lead to unnecessary diagnostic and therapeutic interventions to control asthma. We hope that this case report would increase the awareness of such coexistence in such a young age group. Pediatr Pulmonol. Pediatr Pulmonol. 2012; 47:96–98. © 2010 Wiley Periodicals, Inc.
Clinical investigation of respiratory system admittance in preschool children
Authors: Simpson Shannon J. , Straszek Sune P. , Sly Peter D. , Stick Stephen M. , Hall Graham L.
Published: August 2011

Introduction

The upper airway shunt attenuates measurements of respiratory system impedance (Zrs), with greater impact in young children. Changes in respiratory system admittance, Ars (or Zrs−1), are theoretically independent of the shunt. This study compared the ability of Ars, to standard oscillatory outcomes, to determine respiratory disease and differentiate responses to inhaled bronchial challenges in the clinical setting.

Methods

The forced oscillation technique (FOT) was used to establish reference equations for Ars in healthy preschool children, compare the change in Ars to standard oscillatory outcomes during bronchial challenge with inhaled adenosine‐5′‐monosphate (AMP) and to inhaled bronchodilator in healthy children and those with respiratory disease.

Results

Children with respiratory disease had lower baseline Ars than healthy children (P < 0.05). However, there was no improved ability for Ars to differentiate between bronchodilator responses in healthy and disease populations. In contrast, the response to inhaled AMP occurred at a lower concentration, [25 (3.12–400) mg ml−1; median (10th–90th centile)], as measured by Ars when compared to respiratory system resistance [225 (6.25–400) mg ml−1; P = 0.016].

Conclusion

This study supports the use of Ars during inhaled challenges, but not in response to bronchodilation. Pediatr Pulmonol. Pediatr Pulmonol. 2012; 47:53–58. © 2010 Wiley Periodicals, Inc.
Bronchoscopic techniques for removal of foreign bodies in children's airways
Authors: Rodrigues Ascedio Jose , Scussiatto Evandro Alencar , Jacomelli Márcia , Scordamaglio Paulo Rogério , Gregório Marcelo Gervilla , Palomino Addy Lidvina Mejía , Oliveira Eduardo Quintino , Figueiredo Viviane Rossi
Published: August 2011

Introduction

The management of airway foreign bodies (AFB) can be a dramatic situation in the emergency treatment of children and different techniques have been used to improve the therapeutic success and minimize risks.

Objective

to describe the bronchoscopic techniques used in the treatment of AFB in children referred to the Service of Respiratory Endoscopy of HC‐FMUSP.

Patients and methods

Retrospective analysis of 78 children who underwent bronchoscopy for foreign body removal, at our Service from February 2003 to April 2008.

Results

78 patients with an AFB, aged 08 months to 14 years, with 39 being organic and 39 inorganic foreign bodies. Nine foreign bodies were located in the central airway (four in the larynx and five in the trachea), 34 in the right bronchial tree and 33 in the left bronchial tree. There was bilateral aspiration in two cases. All patients were initially submitted to diagnostic flexible bronchoscopy. A rigid bronchoscope was used in 39 cases; a flexible bronchoscope in 23 and an association of techniques in 15 cases (rigid bronchoscopy, flexible bronchoscopy, suspension laryngoscopy, and fluoroscopy).

Discussion

Although the rigid bronchoscopy is considered the main tool for the removal of foreign bodies from airways, other useful techniques deserve attention as part of the medical training.

Conclusion

The knowledge and association of different methods in pediatric bronchoscopy add the benefits of one method to another, minimizing the chances of therapeutic failure. Pediatr Pulmonol. 2012; 47:59–62. © 2010 Wiley Periodicals, Inc.
Comparison of pressure‐, flow‐, and NAVA‐Triggering in pediatric and neonatal ventilatory care
Authors: Ålander Merja , Peltoniemi Outi , Pokka Tytti , Kontiokari Tero
Published: August 2011

Objective

To compare conventional trigger modes (pressure and flow trigger) to neurally adjusted ventilatory assist (NAVA), a novel sensing technique, and to observe the patient‐ventilator interactions during these modes.

Methods

In this prospective, crossover comparison study in tertiary care pediatric and neonatal intensive care unit, 18 patients (age from 30 weeks of postconceptional age to 16 years) needing mechanical ventilation were randomized. Three patients were excluded from the analysis because of problems in data collection. Patients were ventilated with three different trigger modes (pressure, flow, NAVA), for 10 min each. Patients were randomly allocated to six groups according to the order of trigger modes used.

Results

The primary end point was the time in asynchrony between the patient and the ventilator. Secondary end points were peak and mean airway pressures (MAP), breathing frequency, tidal volume (TV), and vital parameters during each trigger mode. The proportion of time in asynchrony was significantly shorter in the NAVA group (8.8%) than in the pressure (33.4%) and flow (30.8%) groups (P < 0.001 for both). In the NAVA group, the peak inspiratory pressure was 2 to 1.9 cmH2O lower than in the pressure and flow groups, respectively (P < 0.05 for both) and the breathing frequency was 10 breaths/min higher than in the pressure group (P = 0.001). There was a tendency toward a lower MAP (P = 0.047) but the mean TV was about the same (6.4–6.8 ml/kg) in all three groups (P = 0.55). There were no differences in oxygen saturation or vital parameters between the groups.

Conclusion

NAVA offers a novel way of sensing patients' spontaneous breathing and significantly improves short‐term patient‐ventilator synchrony in a pediatric population. Pediatr Pulmonol. 2012; 47:76–83. © 2010 Wiley Periodicals, Inc.
Pre‐existing soft modes of motion uniquely defined by native contact topology facilitate ligand binding to proteins
Authors: Meireles Lidio , Gur Mert , Bakan Ahmet , Bahar Ivet
Published: August 2011

Modeling protein flexibility constitutes a major challenge in accurate prediction of protein–ligand and protein–protein interactions in docking simulations. The lack of a reliable method for predicting the conformational changes relevant to substrate binding prevents the productive application of computational docking to proteins that undergo large structural rearrangements. Here, we examine how coarse‐grained normal mode analysis has been advantageously applied to modeling protein flexibility associated with ligand binding. First, we highlight recent studies that have shown that there is a close agreement between the large‐scale collective motions of proteins predicted by elastic network models and the structural changes experimentally observed upon ligand binding. Then, we discuss studies that have exploited the predicted soft modes in docking simulations. Two general strategies are noted: pregeneration of conformational ensembles that are then utilized as input for standard fixed‐backbone docking and protein structure deformation along normal modes concurrent to docking. These studies show that the structural changes apparently “induced” upon ligand binding occur selectively along the soft modes accessible to the protein prior to ligand binding. They further suggest that proteins offer suitable means of accommodating/facilitating the recognition and binding of their ligand, presumably acquired by evolutionary selection of the suitable three‐dimensional structure.
Structural and binding properties of metal ion chelators relevant to Alzheimer's disease. A theoretical investigation
Authors: Marino Tiziana , Pavelka Matej , Toscano Marirosa , Russo Nino
Published: August 2011

The Copper (II) and Zinc (II) affinities for clioquinol and N,N'‐bis[(5β‐D‐glucopyranosyloxy‐2‐hydroxy)benzyl]‐N,N'‐dimethyl‐ethane‐1,2‐diamine ligands, recently proposed as good chelators in the therapy of Alzheimer's disease, have been studied theoretically by employing density functional theory. Results show that both ligands have a higher affinity for the copper dication and indicate that the copper complex assumes a near planar coordination geometry while the zinc prefers tetrahedral topologies. Furthermore, from the computed OH bond dissociation energies of the isolated ligands, it is clear that both ligands can act as good free radical scavengers being their bond dissociation energies and ionization potentials close to that of tocopherol, which is chosen as reference compound. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012
Optimal impedance control based on body inertia for a hydraulically driven hexapod robot walking on uneven and extremely soft terrain
Authors: Irawan Addie , Nonami Kenzo
Published: August 2011

This paper presents the implementation of impedance control for a hydraulically driven hexapod robot named COMET‐IV, which can walk on uneven and extremely soft terrain. To achieve the dynamic behavior of the hexapod robot, changes in center of mass and body attitude must be taken into consideration during the walking periods. Indirect force control via impedance control is used to address these issues. Two different impedance control schemes are developed and implemented: single‐leg impedance control and center of mass‐‐based impedance control. In the case of single‐leg impedance control, we derive the necessary impedance and adjust parameters (mass, damping, and stiffness) according to the robot legs' configuration. For center of mass–based impedance control, we use the sum of the forces of the support legs as a control input (represented by the body's current center of mass) for the derived impedance control and adjust parameters based on the robot body's configuration. The virtual forces from the robot body's moment of inertia are adapted to achieve optimal control via a linear quadratic regulator method for the proposed indirect attitude control. In addition, a compliant switching mechanism is designed to ensure that the implementation of the controller is applicable to the tripod sequences of force‐based walking modules. Evaluation and verification tests were conducted in the laboratory and the actual field with uneven terrain and extremely soft surfaces. © 2011 Wiley Periodicals, Inc.
Correlation‐based visual odometry for ground vehicles
Authors: Nourani‐Vatani Navid , Borges Paulo Vinicius Koerich
Published: August 2011

Reliable motion estimation is a key component for autonomous vehicles. We present a visual odometry method for ground vehicles using template matching. The method uses a downward‐facing camera perpendicular to the ground and estimates the motion of the vehicle by analyzing the image shift from frame to frame. Specifically, an image region (template) is selected, and using correlation we find the corresponding image region in the next frame. We introduce the use of multitemplate correlation matching and suggest template quality measures for estimating the suitability of a template for the purpose of correlation. Several aspects of the template choice are also presented. Through an extensive analysis, we derive the expected theoretical error rate of our system and show its dependence on the template window size and image noise. We also show how a linear forward prediction filter can be used to limit the search area to significantly increase the computation performance. Using a single camera and assuming an Ackerman‐steering model, the method has been implemented successfully on a large industrial forklift and a 4×4 vehicle. Over 6 km of field trials from our industrial test site, an off‐road area and an urban environment are presented illustrating the applicability of the method as an independent sensor for large vehicle motion estimation at practical velocities. © 2011 Wiley Periodicals, Inc.
Dual‐tracked mobile robot for motion in challenging terrains
Authors: Shoval Shraga , Shapiro Amir
Published: August 2011

In this paper we present a novel design for a dual‐tracked mobile robot. The robot is designed for safe, stable, and reliable motion in challenging terrains, tunnels, and confined spaces. It consists of two tracked platforms connected with a semipassive mechanism. Sensors attached to the connecting mechanism provide redundant localization data that improve the vehicle's autonomous dead reckoning. Each tracked platform mechanically backs up the other platform, resulting in a more robust and reliable operation. The load share between the platforms enables a high payload‐to‐weight ratio even on soft and slippery terrains. The robot's configurations make it suitable for motion in confined spaces such as underground tunnels, collapsed structures, pipes, and caves. The paper presents the mechanical design of the robot, its kinematic model, stability analysis, and a motion planner. Experimental results conducted on prototype models in various types of environments verify the robot capabilities to operate successfully on challenging terrains. The dual‐tracked robot is capable of climbing slopes 50% steeper than a single robot can. Moreover, the improved odometry system shows high accuracy with 2% error of the total travel distance. © 2011 Wiley Periodicals, Inc.
Specimen support for the in situ observation of bending fatigue
Authors: Klaffke D. , Maennig W. W. , Westphal K.
Published: August 2011

An SEM stage (Fig. 1 and 2) is described which allows bending fatigue of metallic specimens in the vacuum of the specimen chamber. With the aid of inductive displacement pick‐ups the angle of bending can be measured (Fig. 3) as well as the momentum of bending (Fig. 4). Thus the mechanical hysteresis can be registrated and the fatigue of the specimen can be controlled. Fig. 5 shows the geometry of the fatigue specimen, which has an electrolytically polished surface area of about 6 × 3 mm2 on which the development of deformation topography can be studied during the fatigue experiment.

The main advantages of the new fatigue apparatus are:

No interruption of cyclic straining is necessary for the investigation of the specimen surface.

The specimen is in vacuum during the complete experiment so that environmental influences are reduced.

The development of surface topography can be monitored continuously.

Differences of the topography (e. g. fatigue cracks) in the phase of tension and compression can be detected.

In the case of fatigue of polycrystalline metals, fatigue cracks often start at the surface of the specimen in slipbands produced by the cyclic straining. Fig. 6 shows typical fatigue slipbands with extrusions and intrusions for pure Al. A slipband crack in a later stage of fatigue is shown in Fig. 7. For the investigation of the distribution of fatigue cracks at the surface the possibility of watching the surface in different phases of bending is a great help. The cyclic crack opening – which depends on the crack depth – can be seen by eye on the TV‐screen and can be recorded on video tape when the frequency of bending is about 1 cycle/s or can be photographed from the record display at very low frequencies of bending. Fig. 8 gives an example of the difference in crack opening in the phase of tension and compression of the specimen surface respectively.
Cathodoluminescence from ZnS and CdSe
Authors: Roberts S. H. , Steeds J. W.
Published: August 2011

A scanning electron microscope adapted for optical imaging of the specimen surface was used to study cathodoluminescence (CL) in the visible spectrum. The materials examined were single crystals and evaporated films of both ZnS and CdSe.

Single crystals of ZnS were observed to consist of parallel striations giving off CL with a wide variety of colours. Crystals of CdSe gave off a red luminescence which was not uniform but the non‐uniformities could not be correlated with any obvious surface features. The evaporated films of both materials exhibited uniform CL: yellow from ZnS and red from CdSe. When the films were examined on their glass substrates, it was found that the level of CL was sensitive to beam intensity. The effects on CL persisted after reduction of the beam intensity.
The identification of pollen grains using cathodoluminescence in the scanning electron microscope
Authors: Soni S.
Published: August 2011

A scanning electron microscope fitted with a sensitive cathodoluminescence detector system has been used for the identification of pollen grains stained with acridine orange or unstained. This approach provides a means of identifying and studying the morphological details of pollens. Cathodoluminescence detection can, in principle, extend the limits of resolution beyond those obtainable with the fluorescence microscope.
Transmission scanning electron microscopical investigation of a gas microjet
Authors: Wurster R.
Published: August 2011

Expansion flows from different kinds of nozzles (pipe, orifice) into the specimen chamber of a scanning electron microscope (JSM 50A, JEOL, Tokyo) were imaged by means of a transmitted electron detection device using its dark field mode of operation.

The experimental videosignal distribution has been numerically transformed in order to get particle number density distributions. Absolute quantification using a thin known foil target yields reasonable particle number densities.

The experimental investigation of a nonstationary gaseous microjet ejected from a circular orifice (20 μm in diameter) in the wall of a closed vessel (6 cm3 volume) provides for another estimation of the particle number density at an arbitrarily selected point on the microjet axis.
A microcomputer‐based system for rapid on‐line stereological analysis in the SEM
Authors: Howell P. G. T. , Reid S. A.
Published: August 2011

A microcomputer‐based image analysis system for the SEM is described. Through two digital‐to‐analog convertors it controls the position of the electron beam on the specimen inside the microscope. A raster of 128 × 128 pixels is created. At each pixel the signal from the BSE detector is sampled an operator‐defined number of times and the median values of the resulting data streams are stored temporarily in the memory of the computer. Stored images may be redisplayed on the visual and record CRTs of the SEM or saved onto a diskette for subsequent recall and analysis. The 256 grey level image is reduced to one having only 64 grey levels and the distribution of the number of counts falling into any of these bins is displayed on the computer monitor, or output to a plotter or printer. The number of counts in each bin represents stereologically the area (and hence volume) fraction of the sample with that grey level. Three levels of threshold may be applied to give four slices in the image. Area (and hence volume) fractions are then calculated, as is the intercept value between slices. This data is output to a printer.

An abbreviated program has also been written to permit greater automation of the analysis of samples of bone. Included is a further reduction in the number of grey levels to 16, and the provision of control for an automatic stage.

Although presently being applied to the study of samples of mineralised biological tissues this system could be used for any investigation requiring rapid and simple stereological analysis of specimens in the SEM.
Cathodoluminescence and gaseous scintillation in the environmental SEM
Authors: Danilatos G. D.
Published: August 2011

A novel detection means for the environmental SEM (ESEM) is described. Certain gases, apart from being the environmental conditioning medium, can also act as a scintillator detector. All signals, such as secondary and backscattered electrons which can cause a particular gas to luminesce, can be detected. It is further concluded that the gas can act as a generalized detector device for all signal‐gas reactions provided some suitable parameter can be monitored. New possibilities in the detection of specimen cathodoluminesce created by the ESEM are demonstrated.
Design and Application of a Quadrupole Detector for Low‐Voltage Scanning Electron Microscopy
Authors: Schmid R. , Brunner M.
Published: August 2011

Scanning electron microscopes operated at low voltages are applied in the inspection and metrology of microstructures as well as in the testing of integrated circuits. The efficiency of a conventional Everhart‐Thornley‐detector is poor in this application, especially if large samples, e.g. wafers, are inspected or tested at small working distances. In addition, the primary beam is deflected and aberrations are added by the extraction field of this detector. A new type of detector for secondary electron recording in low‐voltage scanning electron microscopy was, therefore, designed, built and tested. It utilizes crossed electric and magnetic quadrupoles to compensate for each other in their effect on the primary beam. On the other hand, both fields support the extraction and collection of the secondary electrons. During the test application, the detector showed high efficiency resulting in low‐noise images without any negative effect on the resolution.
Quantitative energy dispersive x‐ray micro‐analysis of thin metal specimens using the STEM
Authors: Schwaab P.
Published: August 2011

This paper gives an outline of the present state of the quantitative energy dispersive x‐ray micro‐analysis according to the Cliff‐Lorimer method in combination with the STEM. Spectrometer efficiency, line intensity fraction, fluorescence yield, ionization cross section and the critical specimen thickness are discussed in particular detail. The main emphasis in this context is placed on the transferability of data given in the literature to other equipment, and on the accuracy of equations for the calculation of the above mentioned parameters.
Low‐temperature scanning electron microscopy of frozen hydrated mouse lung
Authors: Bastacky J. , Hook G. R. , Finch G. L. , Goerke J. , Hayes T. L.
Published: August 2011

A method is presented by which water is preserved as ice during examination of the lung in the scanning electron microscope (SEM). The lung need only be inflated, frozen, transferred to the microscope and examined with the electron beam. Chemical fixation, solvent dehydration, and drying are not necessary.

The low‐temperature SEM of Pawley and Norton [11] maintains lung at −180° C, nearly liquid nitrogen temperature, for extended periods with a Joule‐Thomson refrigerator built into the stage. It has an integral high‐vacuum preparation chamber attached to the microscope column which allows serial fracture, low‐magnification stereo light microscopy, radiant etching, and evaporative coating with gold or carbon. The stage can be tilted from 0° to 45° and rotated a full 360°.

It is demonstrated that the air‐liquid interface in the lung can be examined and that low‐temperature SEM can be used to investigate the shape of alveoli, the patency of the pores of Kohn in the hydrated state, and the shrinkage and distortion of lung with drying.
Biological applications of backscattered electron imaging of scanning electron microscopy
Authors: Soligo D. , Lambertenghi‐Deliliers G.
Published: August 2011

Backscattered electron imaging (BEI) of biological samples was already reported by Watanabe in 1972 (Watanabe 1984). Since then an increasing number of investigators has recognized the usefulness of this way of imaging and employed it not only as a complementary technique to cell surface viewing with secondary electrons but also for its unique analytical potential.
A method for determining the mass thickness of thin films using electron probe microanalysis
Authors: August H.‐J. , Wernisch J.
Published: August 2011

A method is proposed for easy determination of the mass thickness of thin films using electron‐probe microanalysis. The model is based on the function of the depth distribution Ø(qz) of the characteristic x‐ray production and emphasizes the treatment of the physical phenomena in the transition area between the film and the substrate. The method is applicable to a wide range of elements and element combinations (Z>5) and electron acceleration energies. It has been tested by comparing results obtained using this method with data taken from the literature. Errors are small, generally, not exceeding 5%.
SEM voltage contrast mechanism of passivated devices
Authors: Sugiyama N. , Ikeda S. , Uchikawa Y.
Published: August 2011

The mechanism of voltage contrast of passivated devices is investigated. Previous works on the voltage contrast over the passivation are reviewed, and experimental results on glass cover slips with a carbon‐coated surface are described. The voltage contrast is observed over the carbon‐coated equipotential surface. This result cannot be explained by the surface potential model of voltage contrast. An interpretation of the result using a contrast model previously introduced by the authors is provided.
Microvascular corrosion casting with analysis in the scanning electron microscope
Authors: Christoffersonm R. H. , Nilsson B. O.
Published: August 2011

The rat uterus was used as a microcirculatory model for an evaluation of different microvascular corrosion casting techniques. The two major variables determining the quality of casts were the degree of filling of the system cast and the replication of endothelial cells. A simple preparation of a low‐viscosity methyl methacrylate (η = 2–5 cS) was found superior to more viscous resins regarding both variables when infused at a physiological infusion pressure. Differential corrosion in 20% KOH and 5 M HCl at 40°C on a rotating rocker plate with intervening periods in distilled water and ultrasonic treatment was found the most effective corroding procedure. Acceptable conductivity for scanning electron microscopy could be achieved by osmium impregnation from used postfixation buffers, but sputter coating with a 400–10,000 A gold layer was the simplest and fastest method of rendering casts conductive. An arteriolar resistive mechanism not observed previously, segmental arteriolar spasm, was found on arteriolar casts. The imprints of endothelial cell nuclei could conveniently be described by their D/d ratio, that is, the quotient between the longest nuclear diameter and the diameter perpendicular to it. The arteriolar side of a capillary (ϕ 4–10 μm) exhibited arteriolar‐like endothelial cell nuclear imprints (D/d = 2.5–4), while its venular end showed venular‐like endothelial cell nuclear imprints (D/d = 1–1.5), making analysis of the direction of flow within capillary segments possible. “Plastic strips,” considered previously to indicate an avascular circulation in the media of arterioles were observed, and probably represented remnants of uncorroded smooth muscle cells. Localized extravasations of resin might have been caused by gaps between endothelial cells, but this interpretation was restricted to small (< 15 μm) extravasations from post‐capillary venules or capillaries in an area that is known ultrastructurally to possess interendothelial cell gaps.
Colour display of video information in scanning electron microscopy: Principles and applications to physics, geology, soil science, biology, and medicine
Authors: Saparin G. V. , Obyden S. K.
Published: August 2011

From a colourimetric point of view, colour has two independent aspects: brightness and chromaticity. In black and white images, all elements are of the same chromaticity and can be distinguished only by brightness contrast. In the colour image, elements of the same brightness can be discriminated by chromaticity (colour) contrast. Generally, colour image elements can be discriminated both by brightness and by chromaticity. As the human eye can distinguish a number of hues two orders of magnitude larger than the number of grey levels, it is safe to say that the colour image is much more informative than the black and white image. There are some peculiarities of the colour image and methods of its formation in SEM. Two principles of image formation are used. The first consists of the formation of a real colour image in the cathodoluminescence mode. In this case the colour of an image element is determined by the spectrum of the luminescence emission excited in the corresponding point of an object by the electron beam. The second principle is that of colour coding (quasicolour, pseudocolour), when a video signal in colour (either digital or analog) corresponds to a video signal (amplitude, frequency, phase, etc.) produced by any mode in the scanning electron microscope. We present a review of the methods of colour display of video information in scanning electron microscopy and their applications to physics, geology, soil science, biology, and medicine.