bluuebunny/crossref_metadata_2025 huggingface dataset:
The Role of Myocardial Anisotropy in Arrhythmogenesis Associated with Myocardial Ischemia and Infarction
Authors: SPEAR JOSEPH F. , KIEVAL ROBERT S. , MOORE E. NEIL
Published: September 2013

Myocardial Anisotropy in Ischemia and Infarction. Anisotropy is defined as any property of a system that differs depending on the direction in which it is measured. In the heart, the structure of the cardiac myocytes and their electrical coupling via gap junctions confer an anisotropy in the intracellular resistance to current flow in myocardial tissue. This in turn is responsible for anisotropy in conduction in which the velocity and uniformity of impulse conduction is dependent on its direction relative to the normal myocardial fiber orientation and any underlying pathological nonuniformities in cell orientation and coupling. How cells are coupled also influences refractoriness and excitability. Recent experimental evidence has implicated uniform and nonuniform myocardial anisotropy as important substrates that play a role in the initiation and maintenance of arrhythmias in the setting of ischemia and infarction. These studies may provide a focus for the development of new antiarrhythmic modalities that depend on the modulation of cell electrical coupling.
Not All Pacemakers Are Created Equal: MRI Conditional Pacemaker and Lead Technology
Authors: AHMED FOZIA Z. , MORRIS GWILYM M. , ALLEN STUART , KHATTAR RAJDEEP , MAMAS MAMAS , ZAIDI AMIR
Published: September 2013

MRI Conditional Pacemaker and Lead Technology

Due to expanding clinical indications and an aging society there has been an increase in the use of implantable pacemakers. At the same time, due to increased diagnostic yield over other imaging modalities and the absence of ionizing radiation, there has been a surge in demand for magnetic resonance imaging (MRI) assessment, of both cardiac and noncardiac conditions. Patients with an implantable device have a 50–75% chance of having a clinical indication for MRI during the lifetime of their device. The presence of an implantable cardiac device has been seen as a relative contraindication to MRI assessment, limiting the prognostic and diagnostic utility of MRI in many patients with these devices. The introduction of MRI conditional pacemakers will enable more patients to undergo routine MRI assessment without risk of morbidity or device malfunction. This review gives a general overview of the principles and current evidence for the use of MRI conditional implantable cardiac devices. Furthermore, we appraise the differences between those pacemakers currently released to market.
The Impact of Segment Reporting Under the IFRS 8 and SFAS 131 Management Approach: A Research Review
Authors: Nichols Nancy B. , Street Donna L. , Tarca Ann
Published: September 2013

This paper evaluates the impact of adopting the management approach for segment reporting. We review studies of the effect of the application of SFAS 131 and IFRS 8 on the number of reported operating segments and items of disclosure, segment reporting gaps and reconciliations, entitywide geographic disclosures, and competitive harm and decision usefulness of segment information. We report on the advantages and disadvantages of the management approach and explore whether the concerns of critics of adopting the management approach in IFRS 8 have been realized. We also identify opportunities for important and policy‐relevant research in the area of segment reporting based on IFRS 8.
Amyotrophic lateral sclerosis: cell vulnerability or system vulnerability?
Authors: Talbot Kevin
Published: September 2013

Amyotrophic lateral sclerosis (ALS) is a complex neurodegenerative disease with clinical, pathological and genetic overlap with frontotemporal dementia (FTD). No longer viewed as one disease with a single unified cause, ALS is now considered to be a clinicopathological syndrome resulting from a complex convergence of genetic susceptibility, age‐related loss of cellular homeostasis, and possible environmental influences. The rapid increase in recent years of the number of genes in which mutations have been associated with ALS has led to in vitro and in vivo models that have generated a wealth of data indicating disruption of specific biochemical pathways and sub‐cellular compartments. Data implicating pathways including protein misfolding, mRNA splicing, oxidative stress, proteosome and mitochondrial dysfunction in the pathogenesis of ALS reinforce a disease model based on selective age‐dependent vulnerability of a specific population of cells. To the clinical neurologist, however, ALS presents as a disease of focal onset and contiguous spread. Characteristic regional patterns of involvement and progression suggest that the disease does not proceed randomly but via a restricted number of anatomical pathways. These clinical observations combined with electrophysiological and brain‐imaging studies underpin the concept of ALS at the macroscopic level as a ‘system degeneration’. This dichotomy between cellular and systems neurobiology raises the fundamental questions of what initiates the disease process in a specific anatomical site and how the disease is propagated. Is the essence of ALS a cell‐to‐cell transmission of pathology with, for example, a ‘prion‐like’ mechanism, or does the cellular pathology follow degeneration of specific synaptic networks? Elucidating the interaction between cellular degeneration and system level degeneration will aid modeling of the disease in the earliest phases, improve the development of sensitive markers of disease progression and response to therapy, and expand our understanding of the biological basis of clinical and pathological heterogeneity.
Development and preliminary validation of a questionnaire on regular exercise beliefs among patients with chronic obstructive pulmonary disease
Authors: Wang Hsiao‐Chiao , Chao Yann‐Fen C , Tsai Jen‐Chen , Chung Min‐Huey , Yu Yang‐Hao , Hang Liang‐Wen , Lee Shin‐Da
Published: September 2013

Aims and objectives

To develop a Regular Exercise Belief Questionnaire and test its psychometric properties for patients with chronic obstructive pulmonary disease.

Background

Regular exercise has been shown to significantly improve physical capacity and the quality of life of patients with chronic obstructive pulmonary disease. However, their adherence to long‐term exercise is low. To develop an effective strategy for promoting good exercise behaviours, it is important to have a validated instrument to evaluate factors related to engaging in exercise.

Design and methods

A cross‐sectional design was used for the study. Construction of the Regular Exercise Belief Questionnaire was based on the Theory of Planned Behaviour Reliability and validity were assessed using a sample of 136 male patients with chronic obstructive pulmonary disease. The construct validity of the questionnaire was confirmed through exploratory factor analysis and known group technique.

Results

Exploratory factor analysis resulted in an eight‐factor solution that explained 70·4% of the total variance. The internal consistency of the Regular Exercise Belief Questionnaire was 0·83–0·93. The Regular Exercise Belief Questionnaire was preliminarily found to be reliable and exhibited satisfactory validity for patients with chronic obstructive pulmonary disease.

Conclusion

The Regular Exercise Belief Questionnaire is the first theory‐based measure of exercise beliefs among patients with chronic obstructive pulmonary disease. The questionnaire provides an effective method to examine behaviour beliefs, normative beliefs and control beliefs about regular exercise.

Clinical relevance

The measure can be used to periodically evaluate the exercise beliefs in clinics and to examine the effectiveness of exercise programmes in patients with chronic obstructive pulmonary disease. The result of the evaluation could also apply to identify strategies related to promoting exercise behaviours.
Sense of well‐being 10 years after stroke
Authors: Brunborg Birgit , Ytrehus Siri
Published: September 2013

Aims and objectives

To describe factors that promote subjective well‐being in a long‐time perspective of 10 years after stroke.

Background

The research literature describes circumstances that are difficult to deal with after a stroke, but there is relatively little knowledge of factors that contribute to well‐being in a longer‐time perspective than two years after the incident. This study focuses on such conditions in a 10‐year perspective.

Design

Qualitative study

Methods

Qualitative in‐depth interviews were carried out with nine stroke survivors. The interviews addressed their description of factors accounting for adaptation and subjective well‐being after the stroke. Kvale and Brinkmann's (2008, Interview. Sage Publications, Inc., København) guidelines for qualitative research informed the analysis.

Results

Six major themes emerged from these analyses: (1) personal characteristics as the cause of positive adaptation to the new situation, (2) new meaningful activities, (3) new health habits, (4) social networks and family, (5) economical resources and (6) public help. Only a few of the survivors had received any home‐based nursing care or health assistance, but they were nevertheless mainly satisfied with their rehabilitation outcome. Self‐care, health literacy, stamina, a positive way of thinking and attention from family and friends seemed to be of immense importance for adaptation and well‐being.

Conclusion

Personal characteristics and synergy with significant others seem to be the most important factors for having a good and long life after a stroke.

Relevance to clinical practice

The results of this study will contribute to rehabilitation planning and to understanding, assisting and supporting stroke survivors in restoring a good life despite disabilities after the stroke.
A qualitative study of recently bereaved people's beliefs about death: implications for bereavement care
Authors: Draper Peter , Holloway Margaret , Adamson Susan
Published: September 2013

Aims and objectives

To investigate the beliefs of recently bereaved people about death and to explore the implications of these beliefs for bereavement care.

Background

Little is known about recently bereaved people's beliefs about death, although there is evidence that these beliefs may have an impact on health. The funeral provides an opportunity for bereaved people to reflect on their beliefs about death.

Design

A qualitative approach.

Methods

This paper describes one aspect of an interdisciplinary study of the spirituality of contemporary funerals. We obtained access to 46 funerals through funeral directors and other contacts, and interviewed principal mourners to explore their beliefs. Interviews were recorded, transcribed verbatim and analysed thematically.

Results

Three themes emerged that reflected the beliefs and experiences of bereaved people. The first theme describes people's understanding of death in terms of five positions: religious, dualist, eco‐spiritualist, materialist and death‐as‐transition. The second theme addresses a range of views about the possibility of life after death: resurrection, reuniting and reincarnation. The third theme describes ways in which people felt that their relationship with the deceased person continues after death: continuity as sense of presence and continuity as memory, legacy and love. Some people were reluctant to express a firm view about death.

Conclusions

People express a spectrum of beliefs about death. Their beliefs are infrequently linked to formal religious or spiritual perspectives but seem to have an important role in coping with bereavement.

Relevance to clinical practice

This is a unique study illustrating the complexity of bereaved people's beliefs about death. The study provides a research‐based framework within which to understand contemporary beliefs about death, and contributes to our understanding of how health professionals can support recently bereaved people.
Acquired uterine arteriovenous malformation developing in retained products of conception: A diagnostic dilemma
Authors: Goyal Surbhi , Goyal Ankur , Mahajan Surbhi , Sharma Shikha , Dev Geeta
Published: September 2013

Abnormal uterine bleeding in the postabortal period requires meticulous diagnostic work‐up to decide proper management. Imaging modalities including Doppler sonography and magnetic resonance imaging in concert with clinical and laboratory findings are useful to narrow the differential diagnoses but are not definitive. Presence of increased uterine vascularity and arteriovenous shunting is non‐specific and can be detected in a variety of conditions including retained trophoblastic tissue, gestational trophoblastic disease, arteriovenous malformation (AVM), placental polyp and vascular neoplasm. We present here a case of a multiparous woman with unexplained postabortal bleeding posing a diagnostic challenge. Excluding the possibility of AVM before attempting dilatation and curettage in such a clinical scenario is crucial to prevent catastrophic bleeding.
Randomized controlled trial comparing efficacy between a vaginal misoprostol loading and non‐loading dose regimen for second‐trimester pregnancy termination
Authors: Pongsatha Saipin , Tongsong Theera
Published: September 2013

Aim

The aim of this study was to compare the efficacy of vaginal misoprostol loading dose regimen with non‐loading dose regimen for termination of second‐trimester pregnancy with live fetuses.

Material and Methods

A randomized controlled trial was conducted on pregnant women with a live fetus at 14–28 weeks. The patients were randomly allocated to receive either the vaginal misoprostol loading dose regimen (600 mcg, then 400 mcg every 6 h) or the non‐loading dose regimen (400 mcg every 6 h). Failure to abort within 48 h was considered to be a failure.

Results

Of 157 recruited women, 77 were assigned to be in group 1 (loading group) and 80 were in group 2 (non‐loading group). The median abortion time was not statistically different between the groups (14.08; 95% confidence interval: 12.45–17.77 h and 14.58; 95% confidence interval: 12.8–17.27 h, P > 0.05). The rates of abortion within 24 h and 48 h were also comparable between the groups. Fever and chills were more common in the loading group. No other serious complications, such as postpartum hemorrhage and uterine rupture, were found.

Conclusion

Vaginal misoprostol in the loading dose regimen had a similar efficacy to the non‐loading dose regimen but was associated with more adverse maternal effects.
Uncertainty and Status‐Based Asymmetries in the Distinction Between the “Good” Us and the “Bad” Them: Evidence That Group Status Strengthens the Relationship Between the Need for Cognitive Closure and Extremity in Intergroup Differentiation
Authors: Federico Christopher M. , Hunt Corrie V. , Fisher Emily L.
Published: September 2013

In this article, we look at how a key index of discomfort with uncertainty—the need for cognitive closure—interacts with perceived group status to influence a key antecedent of extremism: intergroup differentiation. Because high status provides people with a clear basis for superiority claims, we predicted that individuals with a high need for closure would accentuate intergroup differences in favor of the ingroup when they believe the latter to have higher status relative to outgroups. Two studies provided support for this hypothesis. In Study 1, Whites who were high in need for closure differentiated in favor of the ingroup when they perceived a larger status difference between the high‐status ingroup and lower‐status Black and Latino outgroups. In Study 2, individuals high in need for closure who were randomly assigned to a high‐status (vs. low‐status) group displayed the same pattern.
Culture and Extremism
Authors: Gelfand Michele J. , LaFree Gary , Fahey Susan , Feinberg Emily
Published: September 2013

Much research in the last several decades has examined the social, political, and economic factors that predict terrorism, yet to date, there has been little attention to cultural factors and their relationship to terrorism. We present findings from the Global Terrorism Database showing how numerous cultural dimensions identified in the cultural psychology literature relate to over 80,000 terrorist attacks that occurred between 1970 and 2007. Controlling for economic and religious variables, our results suggest that fatalistic beliefs, rigid gender roles, and greater tightness are related to a greater number of terrorist attacks or fatalities. While fatalism and low gender egalitarianism were related to the overall number of terrorist incidents and fatalities, cultural tightness was related the overall lethality of events, i.e., fatalities per incident. We discuss theoretical and practical implications of our findings.
A Millennial Challenge: Extremism in Uncertain Times
Authors: Fiske Susan T.
Published: September 2013

This comment highlights the relevance and importance of the uncertainty‐extremism topic, both scientifically and societally, identifies common themes, locates this work in a wider scientific and social context, describes what we now know and what we still do not, acknowledges some limitations, foreshadows future directions, and discusses some potential policy relevance. Common themes emerge around the importance of social justice as sound anti‐extremism policy.
Thailand conquered under‐nutrition very successfully but has not slowed obesity
Authors: Chavasit V. , Kasemsup V. , Tontisirin K.
Published: September 2013

Under‐nutrition in Thailand has been successfully controlled for over two decades. However, Thailand is now facing a double‐burden malnutrition problem where under‐ and over‐nutrition coexist. Overweight, obesity, and related diseases are the main nutritional challenges, leading to high costs for curative care. Thailand foresees that nutrition can be an effective strategy for preventing diet‐related non‐communicable chronic diseases, and the country aims to reduce costs for secondary and tertiary health care. Various organizations have conducted national programmes, focusing especially on nutrition education and public campaigns, which have been sustainable and not sustainable. Only milk and certain foods for children are mandated for nutrition labeling. Guideline daily amounts is now the nutrient profile mandated for snack foods in Thailand. To increase efficiency, Thailand's National Food Committee has been established to link food, nutrition and health via a multi‐sectoral approach.
Photo‐Onycholysis Caused by an Unusual Beach Game Activity: A Pediatric Case of a Side Effect Caused by Doxycycline
Authors: Pazzaglia Massimiliano , Venturi Michela , Tosti Antonella
Published: September 2013

Photo‐onycholysis caused by doxycycline has rarely been reported in children. We present the case of a boy who loved to play pinball while at the beach, holding tightly to the machine. He developed a photo‐onycholysis predominantly on his thumbs while he was being treated with 20 mg/day of doxycycline, a low dose but enough to trigger the photoreaction.
Genetic aspects of auxin biosynthesis and its regulation
Authors: Brumos Javier , Alonso Jose M. , Stepanova Anna N.
Published: September 2013

Auxin is an essential plant hormone that controls nearly every aspect of a plant's life, from embryo development to organ senescence. In the last decade the key genes involved in auxin transport, perception, signaling and response have been identified and characterized, but the elucidation of auxin biosynthesis has proven to be especially challenging. In plants, a significant amount of indole‐3‐acetic acid (IAA), the predominant biologically active form of auxin, is synthesized via a simple two‐step route where indole‐3‐pyruvic acid (IPyA) produced from l‐tryptophan by tryptophan aminotransferases (TAA1/TAR) is converted to IAA by the YUC family of flavin monooxygenases. The TAA1/TAR and YUC gene families constitute the first complete auxin biosynthetic pathway described in plants. Detailed characterization of these genes' expression patterns suggested a key role of local auxin biosynthesis in plant development. This has prompted an active search for the molecular mechanisms that regulate the spatiotemporal activity of the IPyA route. In addition to the TAA1/TAR and YUC‐mediated auxin biosynthesis, several alternative routes of IAA production have been postulated to function in plants, but their biological significance is yet to be demonstrated. Herein, we take a genetic perspective to describe the current view of auxin biosynthesis and its regulation in plants, focusing primarily on Arabidopsis.
Regularity encoding and deviance detection of frequency modulated sweeps: Human middle‐ and long‐latency auditory evoked potentials
Authors: Cornella Miriam , Leung Sumie , Grimm Sabine , Escera Carles
Published: September 2013

Fast encoding of frequency modulated (FM) sweeps is crucial for communication. In humans, FM sweeps deviating from the acoustic regularity elicit the mismatch negativity (MMN) evoked potential. Yet, direction sensitivity to FM sweeps is found in animals' primary auditory cortex, upstream of MMN sources found in humans. Here, we were interested in whether direction deviants of complex FM sweeps modulated brain responses earlier than MMN. We used a controlled oddball paradigm, and measured the middle latency responses (MLRs) and the MMN. Our results showed a repetition enhancement to the standards at the Pa component of the MLR and a genuine MMN in the later response range. These results show that, early in the cortical hierarchy, the system is sensitive to the physical characteristics of the repetitive stimuli, but a higher‐order mechanism is needed to detect violations of the acoustic regularity.
Transplantation of Icefish (Salangidae) in China: Glory or Disaster?
Authors: Kang Bin , Deng Junming , Wang Zhongming , Zhang Jie
Published: September 2013

China has a long history of aquaculture, and it contributes the largest aquaculture production worldwide. Aside from expanding aquaculture area and maximizing unit yield, introducing new potential species is greatly encouraged. Icefish (Salangidae) from Taihu Lake have been introduced into other lakes and reservoirs throughout the country since 1979. Neosalanx tangkahkeii was introduced into the southern part of China, and Protosalanx chinensis was introduced into the northern part of China, and both species have been introduced into a small part of central China and Yunnan Province in southwest China. Only one‐third of the transplantation was successful, and most of their yields experienced a burst‐down course. Intrinsic traits of icefish including annual life cycle, higher fecundity, lower trophic level, together with sufficient environment capacity supported the population forming and burst, while overfishing, pollution and short of food could result in the failure of the transplantation. The introduction of icefish brought in economic benefits, but severely threatened biodiversity, especially in plateau lakes in Yunnan Province, caused possible hybridization and carried diseases. According to different environmental conditions and economic needs at regional scale, further transplantation of icefish would face respective fate as resource conservation, rapid development, limitation and insignificance. Increasing attentions on environmental protection and sustainable resource utilization require a fresh evaluation and adjustment of icefish transplantation to achieve an ecologically healthy aquaculture.
Parametric Quantile Regression Based on the Generalized Gamma Distribution
Authors: Noufaily Angela , Jones M. C.
Published: September 2013

We explore a particular fully parametric approach to quantile regression and show that this approach can be very successful. Motivated by the provision of reference charts, we work in the specific context of a positive response variable, whose conditional distribution is modelled by the generalized gamma distribution, and a single covariate, the dependence of parameters of the generalized gamma distribution on which is through simple linear and log-linear forms. With only six parameters at most, such models allow a perhaps surprisingly wide range of distributional shapes that seems adequate for many practical situations. We show that maximum likelihood estimation of the models is computationally quite straightforward, that the estimated quantiles behave well, that use of standard maximum likelihood asymptotics to perform likelihood ratio tests of the number of parameters needed and to give pointwise confidence bands based on the expected information matrix are reliable in this context, and we more tentatively provide a simple goodness-of-fit test of the whole model. Two data analyses, from the health and environmental spheres, are included, along with simulation results. We claim that quite a direct parametric maximum likelihood approach like this—which also obviates the problem of quantile crossing—is adequate for many situations, and there is less need than one might think to resort to more complicated semiparametric and non-parametric approaches to quantile regression in practice.
Accounting for Spatially Varying Directional Effects in Spatial Covariance Structures
Authors: Neto Joaquim Henriques Vianna , Schmidt Alexandra M. , Guttorp Peter
Published: September 2013

Wind direction plays an important role in the spread of air pollutants over a geographical region. We discuss how to include wind directional information in the covariance function of spatial models. Our models are based on a constructive convolution approach, wherein a spatial process is described as a convolution between a spatially varying smoothing kernel and a white noise process. We describe two different ways of accounting for wind direction: one makes use of a non-stationary version of the Matérn covariance function and the other a kernel function that resembles the exponential correlation function. We fit the models proposed to ground level ozone observed at a monitoring network in north-eastern USA. We compare our wind-based covariance models with three other models: two that make use of standard covariance functions, and one whose kernel function varies across space according to latent spatial processes. The inference procedure is performed under the Bayesian paradigm, and uncertainty about parameter estimation is naturally accounted for when performing spatial interpolation. Samples from the posterior distribution under our proposed models are obtained much faster when compared with the model based on latent spatial processes. Although fitted values that are obtained under our proposed models and those obtained based on latent processes are quite similar, our models provided smaller ranges of the predictive posterior credible intervals.
Method for the Creation of a Six Bar Linkage to Simultaneously Carry Two Rigid Bodies Through Four Coordinated Positions
Authors: Zimmerman Ronald A.
Published: September 2013

A method for the creation of a six bar linkage with two ground pivots to simultaneously carry two rigid bodies through four coordinated positions was invented and is described and illustrated herein.

Type synthesis was used to identify possible linkage classes and specific types of possible six bar linkages. A linkage synthesis method which superimposes three Burmester center point curves to create a six bar linkage mechanism with two ground pivots, to carry two coupled rigid bodies simultaneously through four specified, coordinated positions was developed and is demonstrated. An extension of the method to carry two non-coupled rigid bodies through four positions is indicated.

This method was invented in the process of developing a 2nd row automotive truck seat, which is used as an example to illustrate the procedure.

A six bar linkage which carries an automotive truck seat back and seat cushion through four coordinated positions is shown.
Nonlinear Analysis of a 2-DOF Piecewise Linear Aeroelastic System
Authors: Elgohary Tarek A. , Kalmár-Nagy Tamás
Published: September 2013

Aerodynamic forces for a 2-DOF aeroelastic system oscillating in pitch and plunge are modeled as a piecewise linear function. Equilibria of the piecewise linear model are obtained and their stability/bifurcations analyzed. Two of the main bifurcations are border collision and rapid/Hopf bifurcations. Continuation is used to generate the bifurcation diagrams of the system. Chaotic behavior following the intermittent route is also observed. To better understand the grazing phenomenon sets of initial conditions associated with the system behavior are defined and analyzed.
Effects of Air on Enclosure Design of Lead-Zirconate-Titanate (PZT) Thin-Film Diaphragm Microactuators
Authors: Luo Chuan , Hsiao Kai-Yi , Cheung Perry , Lin Howard , Shen A. Q. , Cao G. Z. , Shen I. Y.
Published: September 2013

In this paper, we evaluate performance of two types of piezoelectric diaphragm micro-actuators: open-end design and closed-end design. In the open-end design, the micro-actuator consists of a base silicon diaphragm, a layer of bottom electrode, a layer of lead-zirconate-titanate (PZT) thin film, and a layer of top electrode. The diaphragm is anchored on a silicon substrate by etching the silicon substrate from the back to form a cavity under the diaphragm. In the closed-end design, the bottom of the cavity is sealed with a piece of glass, silicon or PDMS. Experimental results show that the measured displacements from the closed-end design are always 5%–30% lower than those from the open-end design. To explain the experimental results, we hypothesize that the air inside the cavity of the closed-end design behaves like an elastic spring increasing the stiffness of the closed-end design. To confirm the hypothesis, we estimate the stiffness of the air by modeling the air as an ideal gas with a constant temperature. We also model the diaphragm as a lumped spring. Combination of the stiffness from the diaphragm and the air predicts the overall stiffness and displacement of the closed-end design. The predictions agree well with the experimental measurements, indicating that the air in the cavity significantly stiffens the closed-end design.
Innovative Estimating Travel Time Model for Dual-Command Cycle Time of Stewart-Gough Platform in Automated Storage/Retrieval Systems
Authors: Ramadan Muawia , Salah Bashir , Noche Bernd
Published: September 2013

The travel time models of automated storage and retrieval systems (AS/RS’s) have been widely used in distribution and production environments. This paper extends previous work presented on impact design aspects of automated storage/retrieval systems by determining the expected cycle travel time for single command. Our new study improves the throughput performance rate of new AS/RS’s design on cycle travel time that will be specified by estimating travel time for dual command to serve as storage and retrieval (S/R) machine using a parallel wire-based Stewart-Gough platform (parallel wire robot). This improved efficiency in new design is called Stewart-Gough Platform based Automated Storage and Retrieval Systems (SGP-AS/RS’s). A numerical case study has been presented to clarify the travel time analysis based on mini unit-load storage and retrieval system. The improved throughput has been demonstrated by making a comparison between the conventional AS/RS results and the (SGP-AS/RS’s) results in the numerical case study. The effectiveness and ability of (SGP-AS/RS’s) has been proofed by determining the expected travel time for single command and dual command for random and classed-based analysis of storage assignment.
A Robotics Approach to Enhance Conformational Sampling of Proteins
Authors: Cortés Juan , Al-Bluwi Ibrahim
Published: September 2013

Proteins are biological macromolecules that play essential roles in living organisms. Furthermore, the study of proteins and their function is of interest in other fields in addition to biology, such as pharmacology and biotechnology. Understanding the relationship between protein structure, dynamics and function is indispensable for advances in all these areas. This requires a combination of experimental and computational methods, whose development is the object of very active interdisciplinary research. In such a context, this paper presents a technique to enhance conformational sampling of proteins carried out with computational methods such as molecular dynamics simulations or Monte Carlo methods. Our approach is based on a mechanistic representation of proteins that enables the application of efficient methods originating from robotics. The paper explains the generalities of the approach, and gives details on its application to devise Monte Carlo move classes. Results show the good performance of the method for sampling the conformational space of different types of proteins.
Probabilistic Certificate of Correctness for Cyber Physical Systems
Authors: Van der Velden Alex , Koch Patrick , Devanathan Srikanth , Haan Jeff , Naehring Dave , Fox David
Published: September 2013

Cyber Physical Systems couple computational and physical elements, therefore the behavior of geometry (deformations, kinematics), physics and controls needs to be certified using many different tools over a very high dimensional space. Because of the near infinite number of ways such a system can fail meeting its requirements, we developed a Probabilistic Certificate of Correctness (PCC) metric which quantifies the probability of satisfying requirements with consistent statistical confidence.

PCC can be implemented as a scalable engineering practice for certifying complex system behavior at every milestone in the product lifecycle. This is achieved by: creating virtual prototypes at different levels of model abstraction and fidelity; capturing and integrating these models into a simulation process flow; verifying requirements in parallel by deploying virtual prototypes across large organizations; reducing certification time proportional to additional computational resources and trading off sizing, modeling accuracy, technology and manufacturing tolerances against requirements and cost.

This process is an improvement over the V-cycle because verification and validation happens at every stage of the system engineering process thus reducing rework in the more expensive implementation and physical certification phase. The PCC process is illustrated using the example of “Safe Range” certification for an UAV with active flutter control.
On the Analytical Evaluation of the Lubricant Pressure in the Finite Journal Bearing
Authors: Chasalevris Athanasios , Sfyris Dimitris
Published: September 2013

The Reynolds equation for the pressure distribution of the lubricant in a journal bearing with finite length is solved analytically. Using the method of the separation of variables in an additive and in a multiplicative form, a set of particular solutions of the Reynolds equation is added in the general solution of the homogenous Reynolds equation and a closed form expression for the definition of the lubricant pressure is presented. The Reynolds equation is split in four linear ordinary differential equations of second order with non constant coefficients and together with the boundary conditions they form four Sturm-Liouville problems with the three of them to have direct forms of solution and one of them to be confronted using the method of power series. The mathematical procedure is presented up to the point that the application of the boundaries for the pressure distribution yields the final definition of the solution with the calculation of the constants. The current work gives in detail the mathematical path with which the analytical solution is derived, and it ends with the pressure evaluation and a comparison with past numerical solutions and an approximate analytical solution for a finite bearing. Also the parameters of primary interest to the bearing designer, such as load capacity, attitude angle, and stiffness and damping coefficients are evaluated and compared with numerical results.
Investigation of Protein/Lipid Interactions via Scanning Probe Acceleration Microscopy: Theory and Experiment
Authors: Legleiter Justin , Burke Kathleen A. , Yates Elizabeth A.
Published: September 2013

There is great interest in the application of proximal probe techniques to simultaneously image and measure mechancial properties of surfaces with nanoscale spatial resolution. There have been several innovations in generating time-resolved force interaction between the tip and surface while acquiring a tapping mode AFM image. These tip/sample forces contain information regarding mechanical properties of surfaces in an analogous fashion to a force curve experiment. Here, we demonstrate, via simulation, that the maximum and minimum tapping forces change with respect to the Young’s modulus and adhesiveness of a surface, but the roughness of the surfaces has no effect on the tapping forces. Using these changes in tapping forces, we determine the mechanical changes of a lipid membrane after exposure to a huntingtin exon1 (htt exon1) protein with an expanded polyglutamine (polyQ) domain. Expanded polyQ domains in htt is associated with Huntington’s disease, a genetic neurodegenerative disorder. The htt exon1 protein caused regions of increased surface roughness to appear in the lipid membrane, and these areas were associated with decreased elasticity and adhesion to the AFM probe.
Design of a Robotic Gripper Based on a Psittacus Erithacu Beak
Authors: Grammar Alex W. , Williams Robert L.
Published: September 2013

A high versatility, low degrees-of-freedom (DOF) gripper was designed based on avian morphology. Grasping mechanisms for robotic manipulators are often developed for application-specific tasks, such as manipulating a single part or performing a repetitive action. In contrast, more dexterous grippers are complex, multiple-DOF mechanisms. A simple, minimal-DOF, versatile gripper has been developed based on the morphology of the Psittacus Erithacu (African Grey Parrot) beak shape. This species is highly intelligent and uses its beak for digging, gripping, climbing, and foraging. Giving a robot a similar capability would allow the platform to pick up targets such as single, small seeds, liquids, large irregular rocks and soft Robocup style balls. By using the beak as a model for a grasping mechanism the design maintains its versatility without the need for a complex system and allows a large range of targets to be gripped. This gripper is intended for use in the new open-source humanoid robot DARwIn-OP.
A Novel Second-Order Reliability Method (SORM) Using Non-Central or Generalized Chi-Squared Distributions
Authors: Lee Ikjin , Yoo David , Noh Yoojeong
Published: September 2013

This paper proposes a novel second-order reliability method (SORM) using non-central or general chi-squared distribution to improve the accuracy of reliability analysis in existing SORM. Conventional SORM contains three types of errors: (1) error due to approximating a general nonlinear limit state function by a quadratic function at most probable point (MPP) in the standard normal U-space, (2) error due to approximating the quadratic function in U-space by a hyperbolic surface, and (3) error due to calculation of the probability of failure after making the previous two approximations. The proposed method contains the first type of error only which is essential to SORM and thus cannot be improved. However, the proposed method avoids the other two errors by describing the quadratic failure surface with the linear combination of non-central chi-square variables and using the linear combination for the probability of failure estimation. Two approaches for the proposed SORM are suggested in the paper. The first approach directly calculates the probability of failure using numerical integration of the joint probability density function (PDF) over the linear failure surface and the second approach uses the cumulative distribution function (CDF) of the linear failure surface for the calculation of the probability of failure. The proposed method is compared with first-order reliability method (FORM), conventional SORM, and Monte Carlo simulation (MCS) results in terms of accuracy. Since it contains fewer approximations, the proposed method shows more accurate reliability analysis results than existing SORM without sacrificing efficiency.
Compliant Constant-Force Micro-Mechanism for Enabling Dual-Stage Motion
Authors: Zirbel Shannon A. , Aten Quentin T. , Easter Melanie , Jensen Brian D. , Howell Larry L.
Published: September 2013

This paper describes a fully compliant constant-force micro-mechanism that enables dual-stage motion for nanoinjection. Nanoinjection is a recently developed process for delivering DNA into mouse zygotes via electrostatic accumulation and release of the DNA onto a microelectromechanical system (MEMS) lance.

The fully compliant constant-force nanoinjector is a concatenation of two separate mechanisms: a six-bar mechanism with compliant lamina-emergent torsional (LET) joints to raise the lance, and a pair of constant-force crank-sliders with LET joints positioned on either side of the six-bar mechanism to drive the lance forward.

The fully compliant nanoinjector exhibits self-reconfiguring metamorphic motion to first raise the lance to the midline of the zygote and then translate the lance forward with a controlled motion. This dual-stage motion is necessary for the lance to pierce the zygote without causing damage to the cell membrane.

The device achieves two sequential displacement behaviors in a compliant mechanism fabricated from a single, continuous piece of material.
Towards a Technique for Nonlinear Modal Analysis
Authors: Neild Simon A. , Cammarano Andrea , Wagg David J.
Published: September 2013

In this paper we discuss a theoretical technique for decomposing multi-degree-of-freedom weakly nonlinear systems into a simpler form — an approach which has parallels with the well know method for linear modal analysis. The key outcome is that the system resonances, both linear and nonlinear are revealed by the transformation process. For each resonance, parameters can be obtained which characterise the backbone curves, and higher harmonic components of the response. The underlying mathematical technique is based on a near identity normal form transformation. This is an established technique for analysing weakly nonlinear vibrating systems, but in this approach we use a variation of the method for systems of equations written in second-order form. This is a much more natural approach for structural dynamics where the governing equations of motion are written in this form as standard practice. In fact the first step in the method is to carry out a linear modal transformation using linear modes as would typically done for a linear system. The near identity transform is then applied as a second step in the process and one which identifies the nonlinear resonances in the system being considered. For an example system with cubic nonlinearities, we show how the resulting transformed equations can be used to obtain a time independent representation of the system response. We will discuss how the analysis can be carried out with applied forcing, and how the approximations about response frequencies, made during the near-identity transformation, affect the accuracy of the technique. In fact we show that the second-order normal form approach can actually improve the predictions of sub- and super-harmonic responses. Finally we comment on how this theoretical technique could be used as part of a modal testing approach in future work.
Fractal Boundary Explorations for a Nonlinear Two Degree-of-Freedom System
Authors: Owens Benjamin A. M. , Mann Brian P.
Published: September 2013

This paper explores a two degree-of-freedom nonlinearly coupled system with two distinct potential wells. The system consists of a pair of linear mass-spring-dampers with a non-linear, mechanical coupling between them. This nonlinearity creates fractal boundaries for basins of attraction and forced well-escape response. The inherent uncertainty of these fractal boundaries is quantified for errors in the initial conditions and parameter space. This uncertainty relationship provides a measure of the final state and transient sensitivity of the system.
When Technology Has Invisible Hands: Designing Wearable Technologies for Haptic Communication of Emotions
Authors: Bordegoni Monica , Ugur Secil , Carulli Marina
Published: September 2013

In face-to-face communication, touch can establish intimacy, and therefore the presence of tactile stimulation can enhance the interpersonal relationships. While human-human interaction has been shifting from face-to-face physical conversations to electronically mediated form of communication, current technologies are not able to provide a multimodal sensorial experience that can support haptic interaction besides visual and auditory. Within the haptic research fields, affective haptics explore emotional interaction and perception mediated via touch that is simulated by technology. Besides, wearable technology and tangible interfaces can be employed as a solution to bridge the gap between the digital and physical worlds by making the body fully engaged with the interaction. This paper presents findings of a design practice that explores the avenues of affective tactile interaction through wearable technology, which can artificially produce tactile stimulations as medium for instant communication between two people. The findings are presented by the light of theoretical background, observations and analysis of the design practice.
A Graph Grammar Based Approach to Automated Manufacturing Planning
Authors: Fu Wentao , Eftekharian Ata A. , Radhakrishnan Pradeep , Campbell Matthew I. , Fritz Christian
Published: September 2013

In this paper, a new graph grammar representation is proposed to reason about the manufacturability of solid models. The knowledge captured in the graph grammar rules serves as a virtual machinist in its ability to recognize arbitrary geometries and match them to various machine operations. Firstly, a given part is decomposed into multiple sub-volumes, where each sub-volume is assumed to be machined in one operation or to be non-machinable. The decomposed part is converted into a graph so that graph grammar rules can determine the machining details. For each operation, rules determine the face on the part that the tool enters, the type of tools used, the type of machine used, and how the part is fixed within the machine. A candidate plan is a feasible sequence of all of the necessary machining operations needed to manufacture this part. If a given geometry is not machinable, the rules will fail to find operations for all of the partitions.

As a result of this representation, designers can quickly get insights into how a part can be made and how it can be improved (e.g. change features to reduce time and cost). A variety of tests of this algorithm on both simple and complex engineering parts show its effectiveness and efficiency.
The Improved Quadrilateral Discretization Model for the Discrete Topology Optimization of Structures
Authors: Zhou Hong , Annepu Anil K.
Published: September 2013

In the discrete topology optimization, material state is either solid or void and there is no topology uncertainty problem caused by intermediate material state. In this paper, the improved quadrilateral discretization model is introduced for the discrete topology optimization of structures. The design domain is discretized into quadrilateral design cells and each quadrilateral design cell is further subdivided into 16 triangular analysis cells. All kinds of dangling quadrilateral design cells and sharp-corner triangular analysis cells are removed in the improved quadrilateral discretization model to promote the material utilization. To make the designed structures safe, the local stress constraint is directly imposed on each triangular analysis cell. To circumvent the geometrical bias against the vertical design cells, the binary bit-array genetic algorithm is used to search for the optimal topology. The effectiveness of the proposed improved quadrilateral discretization model and its related discrete topology optimization method is verified by two topology optimization examples of structures.