bluuebunny/crossref_metadata_2025 huggingface dataset:
Improving diabetes patient outcomes: Framing research into the chronic care model
Authors: Dancer Susan , Courtney Maureen (Reni)
Published: October 2010

Purpose: To review recent research findings that improve outcomes for type 2 diabetes mellitus (T2DM) patients and frame them within the chronic care model (CCM).

Data sources: Published research studies and research reviews from multiple computerized databases were examined regarding care of patients with T2DM.

Conclusions: Improving outcomes for patients with chronic diseases such as T2DM is a healthcare system imperative. Disease management must shift from an incomplete and scattered focus on episodic care to a comprehensive model of care such as offered by the CCM. This model emphasizes the essential elements of health organization, clinical information systems, decision support, delivery system design, self‐management support, and community required to effectively improve care for these patients.

Implications for practice: Understanding the comprehensive elements needed for quality chronic disease care is essential to improving outcomes. As new interventions for improving T2DM outcomes become available, the nurse practitioner (NP) must be able to evaluate these as they relate to elements of care that comprise the CCM. Framing new research interventions into this model allows the NP to assume a multifaceted leadership role in improving the care and outcomes of these patients.
Quantitative Structure Activity Relationship Study of 2,4,6‐Trisubstituted‐s‐triazine Derivatives as Antimalarial Inhibitors of Plasmodium Falciparum Dihydrofolate Reductase
Authors: Ojha Himanshu , Gahlot Pragya , Tiwari Anjani K. , Pathak Mallika , Kakkar Rita
Published: October 2010

This study presents a quantitative structure activity relationships (QSAR) study on a pool of 19 bio‐active s‐triazine compounds. Molecular descriptors, kappa {1κ}, chi {3χ}, x component of the dipole moment (μx), Coulson charge (qN) on the nitrogen atom sandwiched between the two substituted carbons of the triazine ring, and total energy (ET) obtained from AM1 calculations provide valuable information and have a significant role in the assessment of dihydrofolate reductase (DHFR) inhibitory activity of the compounds. By using the Genetic Function Approach (GFA) technique, five QSAR models have been drawn up with the help of these calculated descriptors and DHFR inhibitory activity data of the molecules. Among the obtained QSAR models presented in the study, statistically the most significant one is a four‐parameter linear equation with the Lack‐of‐Fit value 0.5624, squared correlation coefficient R 2 value of 0.7697, and the squared cross‐validated correlation coefficient RCV2 value of 0.6469. The results are discussed in light of the main factors that influence the DHFR inhibitory activity.
TAM receptors and the clearance of apoptotic cells
Authors: Lemke Greg , Burstyn‐Cohen Tal
Published: October 2010

The Tyro3, Axl, and Mer (TAM) receptor tyrosine kinases and their ligands Gas6 and Protein S are required for the optimal phagocytosis of apoptotic cells in the mature immune, nervous, and reproductive systems. Genetic analyses in mice, rats, and humans reveal that this receptor‐ligand system plays an especially important role in the phagocytosis that is triggered by the “eat‐me” signal phosphatidylserine. Deficiencies in TAM signaling lead to human retinal dystrophies and may contribute to lupus and other human autoimmune diseases. The TAM system appears to interact and cooperate with several other phagocytic networks, including scavenger receptor and integrin‐based systems, and may serve as a signaling hub that integrates these systems.
Immune regulation by apoptotic cell clearance
Authors: Tanaka Masato , Asano Kenichi , Qiu Chun‐Hong
Published: October 2010

Apoptotic cell clearance by phagocytes is essential for the maintenance of self‐tolerance under physiological conditions. Consistent with this, the intravenous injection of apoptotic cells can induce cell‐associated antigen‐specific immunosuppression or tolerance. The intravenous injection of apoptotic cells expressed a fragment of myelin oligodendrocyte glycoprotein (MOG)‐induced MOG‐specific T cell tolerance and suppressed the development of experimental autoimmune encephalomyelitis. However, the suppressive effects of the MOG‐expressing apoptotic cells were largely eliminated by masking phosphatidylserine (PS) exposed on the apoptotic cells, suggesting that the PS‐dependent engulfment of apoptotic cells is required for the tolerance induction. We found that this mechanism of tolerance induction requires the contribution of two cell populations in the splenic marginal zone (MZ). The MZ contains two types of macrophages: marginal metallophilic macrophages and MZ macrophages. These macrophages contribute to the rapid clearance of cell corpses in blood flow. In addition, we also found that CD8α+, CD103+ dendritic cells localizing in the MZ selectively phagocytose blood‐borne dead cells and subsequently present dead cell‐associated antigens to induce antigen‐specific immunosuppression or tolerance.
Apoptosis and autoimmune diseases
Authors: Nagata Shigekazu
Published: October 2010

Every day billions of cells die in our bodies to eliminate those that are harmful, useless, or senescent. The process can be divided into two steps: cell dying and cell clearance. In the first step, death machinery is activated in the cells and quickly kills them. During the second step, dead cells are engulfed by phagocytes, and their components are degraded in the lysosomes of the phagocytes. The death mechanism and the clearance of dead cells have been extensively studied. Mouse lines that are deficient in the death or clearance process have been established, and human patients carrying a mutation in the death machinery have been identified. Data from these mutant mice and human patients indicate that defects in cell death or dead‐cell clearance leads to autoimmunity. This review examines the cell death and clearance processes and briefly discusses the diseases they cause.
ELMO1 signaling in apoptotic germ cell clearance and spermatogenesis
Authors: Elliott Michael R. , Ravichandran Kodi S.
Published: October 2010

Apoptosis and the subsequent removal of dying cells are crucial processes for tissue development and maintenance. Although we are beginning to understand the signaling pathways that control the phagocytic clearance of apoptotic cells, the physiological relevance of these pathways is lacking. During spermatogenesis, over half of the developing germ cells eventually die by apoptosis, yet the signaling pathways that regulate the phagocytic clearance of these dying cells or the impact of this clearance on development and maintenance of the germ cell population is not well understood. The ELMO1/Dock180 proteins form an evolutionarily conserved signaling module that functions as a bipartite guanine nucleotide exchange factor for the small GTPase Rac. The subsequent Rac‐dependent cytoskeletal changes play an important role in the physical engulfment of apoptotic cells. Recent findings demonstrate an in vivo role for ELMO1‐dependent clearance in the testes, with implications for spermatogenesis. Here we will discuss the role of apoptotic cell clearance during spermatogenesis, with a particular emphasis on ELMO1/Dock180 signaling.
Role of class A human thrombospondins in the clearance of dying cells and tolerance induction
Authors: Tabib Adi , Krispin Alon , Mevorach Dror
Published: October 2010

Mammalian thrombospondins (TSPs) are a group of large, secreted, calcium‐binding glycoproteins of complex spatial structure that mediate a wide range of intercellular activities and participate in cell–matrix interactions. This family includes five proteins, divided into two subfamilies, that possess different roles and tissue expression. TSPs have complex roles in mediating cellular processes. Apoptotic cell and phagocyte interactions show a dynamic structure with expanding complexity. However, a vast majority of the consequences of these interactions can be mediated by a single protein. One of these signaling molecules is TSP‐1, which binds to a wide variety of integrin and nonintegrin cell surface receptors and mediates both engulfment and immune modulation. This mechanism is not only important in homeostasis but may also be a major mechanism for inflammation downregulation and in avoiding autoimmunity.
Impact of Mendelian inheritance in cardiovascular disease
Authors: McBride Kim L. , Garg Vidu
Published: October 2010

Cardiovascular disease is a leading cause of mortality worldwide. While the etiology for the majority of cardiovascular disease is presumed to be a combination of genetic and environmental factors, developments in understanding the basic biology of cardiac disorders have been greatly advanced through discoveries made studying heart diseases that exhibit Mendelian forms of inheritance. Most of these diseases primarily affect children and young adults and include cardiomyopathies, arrhythmias, aortic aneurysms, and congenital heart defects. The discovery of the genetic etiologies for these diseases have had significant impact on our understanding of more complex forms of cardiovascular disease and in some cases have led to novel diagnostic and treatment modalities. In this review, we will summarize these seminal genetic discoveries, highlighting a few that have resulted in significant impact on human disease, and discuss the potential utility of studying Mendelian‐inherited heart disease with the development of new genetic technologies and our increased understanding of the human genome.
Peak Cardiac Power Measured Noninvasively With a Bioreactance Technique Is a Predictor of Adverse Outcomes in Patients With Advanced Heart Failure
Authors: Rosenblum Hannah , Helmke Stephen , Williams Paula , Teruya Sergio , Jones Margaret , Burkhoff Daniel , Mancini Donna , Maurer Mathew S.
Published: October 2010

Peak oxygen consumption (VO2) during cardiopulmonary exercise testing (CPET) is a powerful predictor of survival, providing an indirect assessment of cardiac output (CO). Noninvasive indices of CO derived from bioreactance methodology would add significantly to peak VO2 as a means of risk‐stratifying patients with heart failure. In this study, 127 patients (53±14 years of age, 66% male) with heart failure and an average ejection fraction of 31%±15% underwent symptom‐limited CPET using a bicycle ergometer while measuring CO noninvasively by a bioreactance technique. Peak cardiac power was derived from the product of the peak mean arterial blood pressure and CO divided by 451. Follow‐up averaged 404±179 days (median, 366 days) to assess endpoints including death (n=3), heart transplant (n=10), or left ventricular assisted device implantation (n=2). Peak VO2 and peak power had similar areas under the curve (0.77 and 0.76), which increased to 0.83 when combined. Kaplan‐Meier cumulative survival curves demonstrated different outcomes in the subgroup with a VO2 <14 mL/kg/min when stratified by a cardiac power above or below 1.5 W (92.2% vs 82.1% at 1 year and 81.6% vs 58.3% at last follow‐up, P=.02 by log‐rank test). Among patients with heart failure, peak cardiac power measured with bioreactance methodology and peak VO2 had similar associations with adverse outcomes and peak power added independent prognostic information to peak VO2 in those with advanced disease (eg, VO2 <14 mL/kg/min). Congest Heart Fail. 2010;16:254–258. © 2010 Wiley Periodicals, Inc.
CAMBRIDGE, BLOOMSBURY AND PSYCHOANALYSIS
Authors: Pines Malcolm
Published: October 2010

abstract

A vignette on the life of Adrian Stephen with whom I began an analysis in 1946, which ended with his death after 18 months. Adrian was the younger brother of Virginia Woolf, a member of the Bloomsbury Group many of whom had been Apostles at Cambridge. In the 1920s Adrian and his wife Karin qualified in medicine in order to train as psychoanalysts. He featured in a novel by Betty Miller, On the Side of the Angels. His biography is by Jean MacGibbon. Adrian was an important participant in the Freud/Klein Controversial Discussions.
LETTERS FROM BERLIN: ALIX STRACHEY'S VIEWS ON PRE‐FASCIST GERMANY 1924–1925
Authors: De Clerck Rotraut
Published: October 2010

abstract

Taking the correspondence between James and Alix Strachey 1924–1925 between London and Berlin as a starting‐point, the paper investigates the relationship between psychoanalysis and culture in the mid‐1920s in both capitals.
THE LIFE AND TIMES OF THE ASSOCIATION OF THERAPEUTIC COMMUNITIES
Authors: Kennard David
Published: October 2010

abstract

The Association of Therapeutic Communities was born in 1972. I chart its development from vigorous debate in the 1970s to external achievements in the 1980s, near collapse and recovery in the 1990s and professional recognition in the 21st century. Lasting achievements include the journal Therapeutic Communities, a long‐running book series, the annual Windsor conference, regular training events and the Quality Network of Therapeutic Communities.
THERAPEUTIC COMMUNITIES: A PROBLEM OR A SOLUTION FOR PSYCHIATRY? A SOCIOLOGICAL VIEW
Authors: Manning Nick
Published: October 2010

abstract

This paper reviews the place of the therapeutic community in the mental health field, using a sociological framework to understand some key factors that have shaped the field and its response to this approach to therapy. The therapeutic community treatment method in mental health has been contested over the years. It has challenged conventional professional frameworks, it has dealt with a difficult client group, and it has been hostile to or at least awkward about establishing its evidence base. In this paper I reflect on the ‘politics of evidence’ in contested fields. I draw on the analysis of ‘fields’ from the work of French sociologist Pierre Bourdieu, and the analysis of scientific knowledge from an area of the social study of science, ‘actor‐network theory’. I argue that evidence is not neutral in contested fields, and that the technology of trials is not balanced with a theoretically informed understanding of the phenomena under scrutiny (causality versus meaning).
ON BEING AN OBSERVING PARTICIPANT IN A THERAPEUTIC INSTITUTION
Authors: Skogstad Wilhelm
Published: October 2010

abstract

The author builds on two areas of Bob Hinshelwood's work, the Cassel Hospital and institutional observation. He shows how being an observer of oneself and the institution one is working in may lead to a more balanced approach that acknowledges different levels of the organization and their tensions, instead of being caught up in them. He describes a crisis on his unit, the various institutional levels involved in generating the crisis and his way of dealing with it.
In vitro differentiation of retinal pigment epithelium from adult retinal stem cells
Authors: Aruta Claudia , Giordano Francesca , De Marzo Anna , Comitato Antonella , Raposo Graça , Nandrot Emeline F. , Marigo Valeria
Published: October 2010

One of the limitations in molecular and functional studies of the retinal pigment epithelium (RPE) has been the lack of an in vitro system retaining all the features of in vivo RPE cells. Retinal pigment epithelium cell lines do not show characteristics typical of a functional RPE, such as pigmentation and expression of specific markers. The present study was aimed at the development of culture conditions to differentiate, in vitro, retinal stem cells (RSC), derived from the adult ciliary body, into a functional RPE. Retinal stem cells were purified from murine eyes, grown as pigmented neurospheres and induced to differentiate into RPE on an extracellular matrix substrate using specific culture conditions. After 7–15 days of culture, pigmented cells with an epithelial morphology showed a polarized organization and a capacity for phagocytosis. We detected different stages of melanogenesis in cells at 7 days of differentiation, whereas RPE at 15 days contained only mature melanosomes. These data suggest that our protocol to differentiate RPE in vitro can provide a useful model for molecular and functional studies.
Zirconium and hafnium in meteorites
Authors: PATZER Andrea , PACK Andreas , GERDES Axel
Published: October 2010

Abstract– The ratio of the two refractory trace elements zirconium (Zr) and hafnium (Hf) in meteorites has been proposed to be uniform. The most precise value available is 34.3 ± 0.2 (1σ). It was obtained by isotope dilution ICP‐MS applied to 15 chondrites, most of which were carbonaceous chondrites, and six achondrites. We reinvestigated the case and determined Zr/Hf ratios of a broad spectrum of meteoritic samples via laser ablation ICP‐MS. Our sample suite comprised 29 chondrites and five achondrites. The main objective of the study was two‐fold: we intended to verify the accuracy and precision of a relatively fast and inexpensive sample preparation method combined with expeditious laser ablation ICP‐MS techniques. Furthermore, we were looking into the possibility of systematic fine‐scale Zr/Hf variations among bulk meteoritic matter of different classes. The applied fusion technique together with laser ablation ICP‐MS turned out to be well suited to determine relative refractory trace element abundances. Absolute Zr/Hf ratios yield uncertainties of approximately 4% (1σ). As opposed to the most recent findings, we observed variable Zr/Hf ratios in different meteorites ranging from approximately 28 to approximately 38. Our value for Orgueil (CI1) is 34.0 ± 0.3 (1σ). Including literature data, we propose a solar system value of 34.1 ± 0.3. Our data also suggest that H chondrites tend to exhibit higher Zr/Hf ratios (average of 35.6 ± 0.5 [1σ]) while EL6 chondrites rather show low values (average of 30.8 ± 0.6 [1σ]). In addition to examining Zr/Hf ratios, we also explored the content of refractory major elements in different meteorite groups. Here, we found that EL6 chondrites often show very low Ca/Al ratios. The CI1 value for CaO/Al2O3 is 0.804. EL6 chondrites, however, display ratios as low as approximately 0.3. While the variation in Zr/Hf can be explained by fractional condensation processes in the early solar nebula, the observed low Ca/Al ratios in EL6 chondrites are probably attributable to deficits in oldhamite (CaS).
Project ASTER III: A Model for Teacher Professional Development Integrating Science Museum Exhibits with State and National Science Education Content Standards
Authors: Duran Emilio , Ballone‐Duran Lena , Haney Jodi
Published: October 2010

Abstract  This article describes Project ASTER III (Active Science Teaching Encourages Reform), a science professional development program for early elementary teachers, which is based on the premise that people learn best by doing. Very few professional development programs focus on early childhood teacher development and how best to integrate informal science centers into teaching. In ASTER III, development teams—consisting of university scientists, science educators, K‐3 teachers, and educators from a hands‐on science museum—developed 5E lesson plans aligned with the Ohio Academic Content Standards and the National Science Education Standards in conjunction with the museum’s exhibits. This study explores the impact of the ASTER III model on teacher perceptions about the role and effect informal science museum visits have on subsequent teaching and student learning.
The Biomechanics of Erections: Two- Versus One-Compartment Pressurized Vessel Modeling of the Penis
Authors: Mohamed Ahmed M. , Erdman Arthur G. , Timm Gerald W.
Published: October 2010

Previous biomechanical models of the penis simulated penile erections utilizing 2D geometry, simplified 3D geometry or made inaccurate assumptions altogether. These models designed the shaft of the penis as a one-compartment pressurized vessel fixed at one end when in reality it is a two-compartment pressurized vessel in which the compartments diverge as they enter the body and are fixed at two separate anatomic sites. This study utilizes the more anatomically correct two-compartment penile model to investigate erectile function. Simplified 2D and 3D models of the erect penis were developed using the finite element method with varying anatomical considerations for analyzing structural stresses, axial buckling, and lateral deformation. This study then validated the results by building and testing corresponding physical models. Finally, a more complex and anatomically accurate model of the penis was designed and analyzed. When subject to a lateral force of 0.5 N, the peak equivalent von Mises (EVM) stress in the two-compartment model increased by about 31.62%, while in the one-compartment model, the peak EVM stress increased by as high as 70.11%. The peak EVM stress was 149 kPa in the more complex and anatomically accurate penile model. When the perforated septum was removed, the peak EVM stress increased to 455 kPa. This study verified that there is significant difference between modeling the penis as a two- versus a one-compartment pressurized vessel. When subjected to external forces, a significant advantage was exhibited by two corporal based cavernosal bodies separated by a perforated septum as opposed to one corporal body. This is due to better structural integrity of the tunica albuginea when subjected to external forces.
Simulation of a Chain of Collapsible Contracting Lymphangions With Progressive Valve Closure
Authors: Bertram C. D. , Macaskill C. , Moore J. E.
Published: October 2010

The aim of this investigation was to achieve the first step toward a comprehensive model of the lymphatic system. A numerical model has been constructed of a lymphatic vessel, consisting of a short series chain of contractile segments (lymphangions) and of intersegmental valves. The changing diameter of a segment governs the difference between the flows through inlet and outlet valves and is itself governed by a balance between transmural pressure and passive and active wall properties. The compliance of segments is maximal at intermediate diameters and decreases when the segments are subject to greatly positive or negative transmural pressure. Fluid flow is the result of time-varying active contraction causing diameter to reduce and is limited by segmental viscous and valvular resistance. The valves effect a smooth transition from low forward-flow resistance to high backflow resistance. Contraction occurs sequentially in successive lymphangions in the forward-flow direction. The behavior of chains of one to five lymphangions was investigated by means of pump function curves, with variation of valve opening parameters, maximum contractility, lymphangion size gradation, number of lymphangions, and phase delay between adjacent lymphangion contractions. The model was reasonably robust numerically, with mean flow-rate generally reducing as adverse pressure was increased. Sequential contraction was found to be much more efficient than synchronized contraction. At the highest adverse pressures, pumping failed by one of two mechanisms, depending on parameter settings: either mean leakback flow exceeded forward pumping or contraction failed to open the lymphangion outlet valve. Maximum pressure and maximum flow-rate were both sensitive to the contractile state; maximum pressure was also determined by the number of lymphangions in series. Maximum flow-rate was highly sensitive to the transmural pressure experienced by the most upstream lymphangions, suggesting that many feeding lymphatics would be needed to supply one downstream lymphangion chain pumping at optimal transmural pressure.
Statistical-noise effect on discrete power spectrum of line-edge and line-width roughness
Authors: Hiraiwa Atsushi , Nishida Akio
Published: October 2010

The control of line-edge roughness (LER) and line-width roughness (LWR) is a key issue in addressing the growing challenge of device variability in large-scale integrations. The accurate characterization of LER and LWR forms a basis for this effort and mostly hinges on reducing the effects of noise inherent in experimental results. This article reports how a power spectral density (PSD) is affected by a statistical noise that originates from the finiteness of the number NL of available samples. To achieve this, the authors numerically generated line-width data using the Monte Carlo (MC) method and assuming an exponential autocorrelation function (ACF). By analyzing the pseudoexperimental PSDs obtained using the MC data, they found that the standard deviation η of normalized analysis errors was determined by the total number NALL of width data used in each analysis, regardless of NL and the number N of width data in each line segment. The authors found that η decreased with NALL approximately in inverse proportion to NALL3/4. It is noteworthy that they could obtain accurate results even in the case of NL=1 as long as NALL was sufficiently large, although the distribution of PSDs was large due to a large statistical noise. This resulted from the fact that the PSD distribution was not completely irregular, but centered at the true value and that the best-fitted PSD accordingly approached the true one with an increasing N. On the other hand, η at a fixed NALL decreased with the ratio Δy/ξ of an interval Δy of width data to a correlation length ξ, approximately in inverse proportion to (Δy/ξ)3/8. As a result, NALL at a specified η decreased with Δy/ξ in inverse proportion to the square root of Δy/ξ in the case when Δy/ξ was 0.3 or smaller. Beyond this threshold of Δy/ξ, the authors needed to increase NALL markedly to achieve the same accuracy of analyses. This comes from a decrease in the range of the PSD with an increasing Δy/ξ and a subsequent loss of sensitivity of the PSD to the change of ξ. Based on these results, they established guidelines for accurate analyses as follows: Δy/ξ≤0.3 and NALL≥Aη−4/3(Δy/ξ)−1/2, where A is 1.8×102 for ξ and 7.2×101 for the variance of widths, respectively. Equivalently in terms of the total measurement length LALL, instead of NALL, the guidelines are given in Δy/ξ≤0.3 and LALL/ξ≥Aη−4/3(Δy/ξ)1/2 using the same A’s as those of NALL. Being expressed in universal forms like these, the guidelines of this study can be applied to many practical problems beyond LER and LWR to accurately analyze PSDs, as long as the stochastic processes have exponential ACFs.
Defect-free etching process for GaAs/AlGaAs hetero-nanostructure using chlorine/argon mixed neutral beam
Authors: Wang Xuan-Yu , Huang Chi-Hsien , Ohno Yuzo , Igarashi Mokoto , Murayama Akihiro , Samukawa Seiji
Published: October 2010

The authors studied a GaAs/Al0.3Ga0.7As hetero-nanostructure etching process, neutral beam (NB) etching with chlorine (Cl2) and argon (Ar) mix gas. The effect of different mixing ratios of chlorine and argon has been investigated. The results showed that when pure chlorine NB (Cl-NB) was used, the pillar formation problem was observed on the etched surface. By increasing the Ar/(Cl2+Ar) gas mixing ratio, the pillar can be eliminated and the roughness of etched surface smoothed. As an Ar/(Cl2+Ar) gas mixing ratio of 78% was used, the root-mean-square roughness of etched surfaces of both GaAs and Al0.3Ga0.7As is about 0.6 nm, which is almost the same as those of as-received samples. Meanwhile, the etching selectivity of GaAs/Al0.3Ga0.7As can be kept close to 1, which would help to etch a clear and smooth profile. Additionally, the high-resolution transmission-electron microscopy image of the GaAs etch profile shows that no crystalline defect was observed on the etched surface.
Effect of Al doping on resistive switching behavior of NiOx films for nonvolatile memory application
Authors: Kim Jonggi , Na Heedo , Oh Jinho , Ko Dae-Hong , Sohn Hyunchul
Published: October 2010

In this work, the authors investigated the effect of Al doping on the resistance switching characteristics of sputtered NiOx films. Pt/NiOx/Pt metal-insulator-metal (MIM) stacks were fabricated by reactive dc magnetron sputtering with various Al contents in NiOx films and the resistance switching behavior of the MIM stack was characterized in conjunction with physical property, such as chemical bonding of NiOx. Al doping into NiOx films improved the endurance of SET/RESET operations, the distribution of VSET, and the memory window compared to the undoped NiOx films. X-ray photoemission spectroscopy showed that the Al doping caused the density of metallic nickel (Ni0) to be increased with the reduction of Ni3+ concentration. It was considered that the increase of metallic nickel (Ni0) in Al-doped NiOx films enhanced the repeated formation and rupture of conductive filaments during resistive switching operation, resulting in the enhanced endurance and the narrowed VSET distribution.
Optical and computed evaluation of keyhole diffractive imaging for lensless x-ray microscopy
Authors: Dai Bing , Zhu Diling , Jaroensri Ronnachai , Kulalert Kanokwan , Pianetta Piero , Pease R. Fabian W.
Published: October 2010

X-ray microscopy without the need to focus the x-rays is obviously desirable. Thus, various ways of reconstructing the image from the far-field diffraction pattern have been demonstrated during the last decade. Here, the authors describe a variant of keyhole diffractive imaging in which the knowledge of the illuminating wavefront is used in the reconstruction. Unlike prior work in keyhole imaging in which a diverging beam was used, the authors employ a collimated beam such as emerges from a free electron x-ray source. From both computer simulations and scaled optical experiments, the authors found that the reconstruction is best when the shape is a right-angled triangle. For the authors’ samples, the best size of the triangle is one that covers about half of a rectangle 3000×3000 wavelengths. If the area is smaller, then the time to cover the entire sample is too long; if larger, then the reconstruction takes far longer and results in a noisy image. From the authors’ scaled experiment conducted under blind conditions (no a prior knowledge of the sample), it appears that a resolution of 10 nm should be readily achievable at an x-ray wavelength of 0.18 nm.
CO
2
laser treatment for stabilization of the superhydrophobicity of carbon nanotube surfaces
Authors: Ramos S. C. , Vasconcelos G. , Antunes E. F. , Lobo A. O. , Trava-Airoldi V. J. , Corat E. J.
Published: October 2010

In this work, the authors demonstrate the formation of stable superhydrophobic vertically aligned multiwalled carbon nanotube (VACNT) surfaces through CO2 laser irradiance, in which the contact angle value reached 161°. VACNT arrays were synthesized by microwave plasma chemical vapor deposition using N2/H2/CH4 [10/90/14 SCCM (SCCM denotes cubic centimeter per minute at STP)]. CO2 laser technique was applied on VACNT surfaces with irradiance at different laser powers to promote the great stability of superhydrophobic surfaces. Contact angle measurement reveals that irradiated VACNT surface is superhydrophobic at all irradiances tested. Unlike as-grown VACNT, the samples treated with CO2 laser show no sign of water seepage even after a prolonged period of time (∼24 h). This characteristic is very interesting and has various possible functional applications in micro- and nanomaterials and devices.
A generalized smoothness criterion for acoustic-to-articulatory inversion
Authors: Ghosh Prasanta Kumar , Narayanan Shrikanth
Published: October 2010

The many-to-one mapping from representations in the speech articulatory space to acoustic space renders the associated acoustic-to-articulatory inverse mapping non-unique. Among various techniques, imposing smoothness constraints on the articulator trajectories is one of the common approaches to handle the non-uniqueness in the acoustic-to-articulatory inversion problem. This is because, articulators typically move smoothly during speech production. A standard smoothness constraint is to minimize the energy of the difference of the articulatory position sequence so that the articulator trajectory is smooth and low-pass in nature. Such a fixed definition of smoothness is not always realistic or adequate for all articulators because different articulators have different degrees of smoothness. In this paper, an optimization formulation is proposed for the inversion problem, which includes a generalized smoothness criterion. Under such generalized smoothness settings, the smoothness parameter can be chosen depending on the specific articulator in a data-driven fashion. In addition, this formulation allows estimation of articulatory positions recursively over time without any loss in performance. Experiments with the MOCHA TIMIT database show that the estimated articulator trajectories obtained using such a generalized smoothness criterion have lower RMS error and higher correlation with the actual measured trajectories compared to those obtained using a fixed smoothness constraint.
Radiofrequency electrode vibration-induced shear wave imaging for tissue modulus estimation: A simulation study
Authors: Bharat Shyam , Varghese Tomy
Published: October 2010

Quasi-static electrode displacement elastography, used for in-vivo imaging of radiofrequency ablation-induced lesions in abdominal organs such as the liver and kidney, is extended in this paper to dynamic vibrational perturbations of the ablation electrode. Propagation of the resulting shear waves into adjoining regions of tissue can be tracked and the shear wave velocity used to quantify the shear (and thereby Young’s) modulus of tissue. The algorithm used utilizes the time-to-peak displacement data (obtained from finite element analyses) to calculate the speed of shear wave propagation in the material. The simulation results presented illustrate the feasibility of estimating the Young’s modulus of tissue and is promising for characterizing the stiffness of radiofrequency-ablated thermal lesions and surrounding normal tissue.
Passive cavitation mapping for localization and tracking of bubble dynamics
Authors: Gyöngy Miklós , Coussios Constantin-C.
Published: October 2010

Current acoustic techniques for studying cavitation dynamics are only readily applicable to single-bubble activity, while optical methods can only be used in transparent media. However, multi-bubble cavitation often occurs in opaque media such as biological tissue. Here, the signals received passively by each of the 64 channels of a diagnostic ultrasound array are used to localize and separate emissions from several bubble clusters cavitating in agar gel, thereby providing a method of observing cavitation dynamics. The method has a high spatiotemporal resolution and is applicable to cavitation in opaque media.
A neural network based model for urban noise prediction
Authors: Genaro N. , Torija A. , Ramos-Ridao A. , Requena I. , Ruiz D. P. , Zamorano M.
Published: October 2010

Noise is a global problem. In 1972 the World Health Organization (WHO) classified noise as a pollutant. Since then, most industrialized countries have enacted laws and local regulations to prevent and reduce acoustic environmental pollution. A further aim is to alert people to the dangers of this type of pollution. In this context, urban planners need to have tools that allow them to evaluate the degree of acoustic pollution. Scientists in many countries have modeled urban noise, using a wide range of approaches, but their results have not been as good as expected. This paper describes a model developed for the prediction of environmental urban noise using Soft Computing techniques, namely Artificial Neural Networks (ANN). The model is based on the analysis of variables regarded as influential by experts in the field and was applied to data collected on different types of streets. The results were compared to those obtained with other models. The study found that the ANN system was able to predict urban noise with greater accuracy, and thus, was an improvement over those models. The principal component analysis (PCA) was also used to try to simplify the model. Although there was a slight decline in the accuracy of the results, the values obtained were also quite acceptable.
Basis of acoustic discrimination of chinook salmon from other salmons by echolocating Orcinus orca
Authors: Au Whitlow W. L. , Horne John K. , Jones Christopher
Published: October 2010

The “resident” ecotype of killer whales (Orcinus orca) in the waters of British Columbia and Washington State have a strong preference for Chinook salmon even in months when Chinook comprise less than about 10% of the salmon population. The foraging behavior of killer whales suggests that they depend on echolocation to detect and recognize their prey. In order to determine possible cues in echoes from salmon species, a series of backscatter measurements were made at the Applied Physics Laboratory (Univ. of Wash.) Facility on Lake Union, on three different salmon species using simulated killer whale echolocation signals. The fish were attached to a monofilament net panel and rotated while echoes were collected, digitized and stored on a laptop computer. Three transducer depths were used; same depth, 22° and 45° above the horizontal plane of the fish. Echoes were collected from five Chinook, three coho and one sockeye salmon. Radiograph images of all specimens were obtained to examine the swimbladder shape and orientation. The results show that echo structure from similar length but different species of salmon were different and probably recognizable by foraging killer whales.
Computation of the acoustic radiation force using the finite-difference time-domain method
Authors: Cai Feiyan , Meng Long , Jiang Chunxiang , Pan Yu , Zheng Hairong
Published: October 2010

The computational details related to calculating the acoustic radiation force on an object using a 2-D grid finite-difference time-domain method (FDTD) are presented. The method is based on propagating the stress and velocity fields through the grid and determining the energy flow with and without the object. The axial and radial acoustic radiation forces predicted by FDTD method are in excellent agreement with the results obtained by analytical evaluation of the scattering method. In particular, the results indicate that it is possible to trap the steel cylinder in the radial direction by optimizing the width of Gaussian source and the operation frequency. As the sizes of the relating objects are smaller than or comparable to wavelength, the algorithm presented here can be easily extended to 3-D and include torque computation algorithms, thus providing a highly flexible and universally usable computation engine.
Planar nearfield acoustical holography in moving fluid medium at subsonic and uniform velocity
Authors: Kwon Hyu-Sang , Niu Yaying , Kim Yong-Joe
Published: October 2010

Nearfield acoustical holography (NAH) data measured by using a microphone array attached to a high-speed aircraft or ground vehicle include significant airflow effects. For the purpose of processing the measured NAH data, an improved nearfield acoustical holography procedure is introduced that includes the effects of a fluid medium moving at a subsonic and uniform velocity. The convective wave equation along with the convective Euler’s equation is used to develop the proposed NAH procedure. A mapping function between static and moving fluid medium cases is derived from the convective wave equation. Then, a conventional wave number filter designed for static fluid media is modified to be applicable to the moving fluid cases by applying the mapping function to the static wave number filter. In order to validate the proposed NAH procedure, a monopole simulation at the airflow speed of Mach=−0.6 is conducted. The reconstructed acoustic fields obtained by applying the proposed NAH procedure to the simulation data agree well with directly-calculated acoustic fields. Through an experiment with two loudspeakers performed in a wind tunnel operating at Mach=−0.12, it is shown that the proposed NAH procedure can be also used to reconstruct the sound fields radiated from the two loudspeakers.
Receiving sensitivity and transmitting voltage response of a fluid loaded spherical piezoelectric transducer with an elastic coating
Authors: George Jineesh , Ebenezer D. D. , Bhattacharyya S. K.
Published: October 2010

A method is presented to determine the response of a spherical acoustic transducer that consists of a fluid-filled piezoelectric sphere with an elastic coating embedded in infinite fluid to electrical and plane-wave acoustic excitations. The exact spherically symmetric, linear, differential, governing equations are used for the interior and exterior fluids, and elastic and piezoelectric materials. Under acoustic excitation and open circuit boundary condition, the equation governing the piezoelectric sphere is homogeneous and the solution is expressed in terms of Bessel functions. Under electrical excitation, the equation governing the piezoelectric sphere is inhomogeneous and the complementary solution is expressed in terms of Bessel functions and the particular integral is expressed in terms of a power series. Numerical results are presented to illustrate the effect of dimensions of the piezoelectric sphere, fluid loading, elastic coating and internal material losses on the open-circuit Receiving Sensitivity and Transmitting Voltage Response of the transducer.
Power dissipation and temperature distribution in piezoelectric ceramic slabs
Authors: Thomas D. , Ebenezer D. D. , Srinivasan Sivakumar M.
Published: October 2010

A method is presented to determine power dissipation in one-dimensional piezoelectric slabs with internal losses and the resulting temperature distribution. The length of the slab is much greater than the lateral dimensions. Losses are represented using complex piezoelectric coefficients. It is shown that the spatially non-uniform power dissipation density in the slab can be determined by considering either hysteresis loops or the Poynting vector. The total power dissipated in the slab is obtained by integrating the power dissipation density over the slab and is shown to be equal to the power input to the slab for special cases of mechanically and electrically excited slabs. The one-dimensional heat equation that includes the effect of conduction and convection, and the boundary conditions, are then used to determine the temperature distribution. When the analytical expression for the power dissipation density is simple, direct integration is used. It is shown that a modified Fourier series approach yields the same results. For other cases, the temperature distribution is determined using only the latter approach. Numerical results are presented to illustrate the effects of internal losses, heat conduction and convection coefficients, and boundary conditions on the temperature distribution.
Cancellous bone analysis with modified least squares Prony’s method and chirp filter: Phantom experiments and simulation
Authors: Wear Keith A.
Published: October 2010

The presence of two longitudinal waves in porous media is predicted by Biot’s theory and has been confirmed experimentally in cancellous bone. When cancellous bone samples are interrogated in through-transmission, these two waves can overlap in time. Previously, the Modified Least-Squares Prony’s (MLSP) method was validated for estimation of amplitudes, attenuation coefficients, and phase velocities of fast and slow waves, but tended to overestimate phase velocities by up to about 5%. In the present paper, a pre-processing chirp filter to mitigate the phase velocity bias is derived. The MLSP/chirp filter (MLSPCF) method was tested for decomposition of a 500 kHz-center-frequency signal containing two overlapping components: one passing through a low-density-polyethylene plate (fast wave) and another passing through a cancellous-bone-mimicking phantom material (slow wave). The chirp filter reduced phase velocity bias from 100 m/s (5.1%) to 69 m/s (3.5%) (fast wave) and from 29 m/s (1.9%) to 10 m/s (0.7%) (slow wave). Similar improvements were found for 1) measurements in polycarbonate (fast wave) and a cancellous-bone-mimicking phantom (slow wave), and 2) a simulation based on parameters mimicking bovine cancellous bone. The MLSPCF method did not offer consistent improvement in estimates of attenuation coefficient or amplitude.
Measured wavenumber: Frequency spectrum associated with acoustic and aerodynamic wall pressure fluctuations
Authors: Arguillat Blandine , Ricot Denis , Bailly Christophe , Robert Gilles
Published: October 2010

Direct measurements of the wavenumber-frequency spectrum of wall pressure fluctuations beneath a turbulent plane channel flow have been performed in an anechoic wind tunnel. A rotative array has been designed that allows the measurement of a complete map, 63×63 measuring points, of cross-power spectral densities over a large area. An original post-processing has been developed to separate the acoustic and the aerodynamic exciting loadings by transforming space-frequency data into wavenumber-frequency spectra. The acoustic part has also been estimated from a simple Corcos-like model including the contribution of a diffuse sound field. The measured acoustic contribution to the surface pressure fluctuations is 5% of the measured aerodynamic surface pressure fluctuations for a velocity and boundary layer thickness relevant for automotive interior noise applications. This shows that for aerodynamically induced car interior noise, both contributions to the surface pressure fluctuations on car windows have to be taken into account.
Imprecise singing is widespread
Authors: Pfordresher Peter Q. , Brown Steven , Meier Kimberly M. , Belyk Michel , Liotti Mario
Published: October 2010

There has been a recent surge of research on the topic of poor-pitch singing. However, this research has not addressed an important distinction in measurement: that between accuracy and precision. With respect to singing, accuracy refers to the average difference between sung and target pitches. Precision, by contrast, refers to the consistency of repeated attempts to produce a pitch. A group of 45 non-musician participants was asked to vocally imitate unfamiliar 5-note melodies, as well as to sing a series of familiar melodies from memory (e.g., Happy Birthday). The results showed that singers were more accurate than they were precise, and that a majority of participants could justifiably be categorized as imprecise singers. Accuracy and precision measures were correlated with one another, and conditional-probability analyses suggested that accuracy predicted precision more so than the converse. Finally, performance differences across groups of singers were greater for the imitation of unfamiliar tone sequences than for the recall of familiar melodies.
On the dynamics of the clavichord: From tangent motion to sound
Authors: d’Alessandro Christophe
Published: October 2010

An experimental study of variations in the sound of clavichord notes at different dynamic levels is described. Radiated acoustic signal, tangent velocity and two tangent-string contact signals are synchronously measured for all 51 notes of an unfretted instrument. More than ten repeated measures are recorded in order to obtain as much variation in dynamic level as possible. The tangent motion, expressed in terms of velocity, is studied in the time and frequency domains. A model of the tangent-string contact point velocity is proposed. Then, three aspects of the sounded tones are analyzed: SPL and its relationship to tangent velocity, spectral slope, and pitch variations. These results indicate a linear relationship between sound pressure level and tangent peak log velocity. Spectral slope seems almost constant independent of tangent velocity and dynamic level. Both tangent velocity and finger pressure are shown to influence the fundamental frequency. In conclusion, controlling both finger velocity and finger pressure may prove challenging for the player, and this may explain why the sound quality of the clavichord depends so much on the players ability.