bluuebunny/crossref_metadata_2025 huggingface dataset:
Duration of Erection: Does It Really Matter? A Randomized, Double-Blind Clinical Trial to Assess the Impact of Vardenafil ODT on Duration of Erection and Its Correlation with Patients' and Partners' Sexual Quality of Life and Duration of Intercourse: The VADEOPEN Study
Authors: Martin-Morales Antonio , Gutiérrez-Hernández Pedro , Romero-Otero Javier , Romero-Martín José A.
Published: March 2014

Introduction

Stopwatch-assessed duration of erection has been proposed as an objective and reliable efficacy end point for erectile dysfunction (ED) treatments.

Aim

The aim of this study is to assess vardenafil orodispersible tablets' (ODTs) efficacy in terms of duration of erection and (i) its correlation with other efficacy end points and male and female sexual quality of life (QoL) and (ii) its impact on intercourse duration.

Methods

Randomized, double-blind, placebo-controlled, multicenter study comparing the efficacy and safety of vardenafil ODT 10 mg on-demand over 12 weeks in 127 patients with ED was carried out.

Main Outcome Measures

Primary efficacy end points were stopwatch-assessed duration of erection (min) at any attempt and when leading to successful intercourse, and the erectile function domain of the International Index of Erectile Function (EF-IIEF) score. Secondary end points were sexual encounter profile (SEP) 3 response rate and male sexual QoL. End points in participating women (N = 46) were stopwatch-assessed duration of intercourse and sexual QoL.

Results

At week 12/last observation carried forward, patients taking vardenafil ODT had longer duration of erections (at any attempt or leading to successful intercourse) vs. placebo (least square mean ± standard error 10.2 ± 0.9 minutes vs. 7.9 ± 1.0 minutes, and 10.4 ± 0.8 vs. 8.3 ± 1.0 minutes, respectively), and significant increases in EF-IIEF scores, the SEP-3 response, and all sexual QoL items. An increased duration of intercourse was also observed. Female sexual QoL improved significantly. Both duration end points strongly correlated with EF-IIEF scores, and the three end points correlated well with SEP-3 response. Correlation was good with sexual QoL scores in men and women and with duration of intercourse, with differences between treatment groups only for duration end points. Safety was similar in both groups.

Conclusion

This study provides further evidence for the consistency and reliability of the stopwatch-assessed duration of erection as an efficacy end point for ED treatments, with “duration of erection leading to successful intercourse” showing better properties than duration at any attempt.
Intimate Partner Violence: Relationships Between Alexithymia, Depression, Attachment Styles, and Coping Strategies of Battered Women
Authors: Craparo Giuseppe , Gori Alessio , Petruccelli Irene , Cannella Vincenza , Simonelli Chiara
Published: March 2014

Introduction

One of the most common forms of violence against women is the intimate partner violence (IPV). This term includes physical, sexual, and emotional abuse and controlling behaviors by an intimate partner.

Aim

This exploratory study investigates the relationship between alexithymia, adult attachment styles, depression, and coping strategies in a group of female victims of IPV and a control group.

Methods

Participants were 80 female victims of IPV with an age range from 18 years to 54 years (mean 31.62; standard deviation 9.81). The control group included 80 women with no history of IPV with an age range from 19 years to 37 years (mean 25.05; standard deviation 3.67).

Main Outcome Measures

We administered the following self-report questionnaires: (i) 20-Item Toronto Alexithymia Scale (TAS-20); (ii) Coping Orientation Problems Experienced; (iii) Beck Depression Inventory (BDI)-II; and (iv) Attachment Style Questionnaire (ASQ).

Results

Compared with control group, the IPV group showed higher mean scores on TAS-20 (52.9 vs. 41.1, P < 0.001) and BDI-II (19.50 vs. 9.95, P < 0.001). In both groups, we found significant correlations between BDI-II and TAS-20 total scores (P < 0.001) and between BDI-II and the following dimensions of ASQ: confidence (P < 0.001), discomfort with closeness (P = 0.002), relationships as secondary (P < 0.001), need for approval (P < 0.001), and preoccupation with relationships (P < 0.001). Differently from the control group, in the IPV group, social support correlated significantly and positively (P < 0.001) with the dimension preoccupation with relationships on ASQ, but not with the secure attachment style.

Conclusions

In comparison to the control group, alexithymia, depressive symptoms, and an insecure attachment style were negatively correlated with the ability to cope with stress for women in the IPV group.
Critical Factors in the Oral Control Needed for Chewing and Swallowing
Authors: Logemann Jerilyn A.
Published: March 2014

Normal oropharyngeal swallowing is a complex set of neuromotor behaviors containing three phases: (1) oral preparation to break food down to a swallowable consistency; (2) oral phase, which propels food from the mouth; (3) pharyngeal phase creates pressure to push food into the esophagus, and includes valve functions, which prevent food from entering the nose or airway and allow food into the esophagus. Systematic changes in normal oropharyngeal swallow are based on volume, viscosity, temperature and food textures/taste of the food swallowed as well as age. Patients with oropharyngeal swallowing difficulties (dysphagia) react differently to these systematic variables in food characteristics. This review manuscript presents the results of a series of studies that examine the role of each of the stages of the oropharyngeal swallow. The importance of the definition of food viscosity in the care of dysphagic patients and the role of food production companies in this effort are emphasized.

Practical Applications

The body of research work that we are summarizing and reviewing here is designed to provide a baseline regarding normal oropharyngeal swallow function in adults against which abnormalities in swallow can be compared. Understanding swallow disorders in the oral and pharyngeal stages of oropharyngeal deglutition enables food scientists to develop food textures, which are most successfully swallowable by specific types of dysphagic patients. All of the studies reviewed here have been approved by the Northwestern University Institutional Review Board.
Infected hematopoietic stem cells and with integrated HBV DNA generate defective T cells in chronic HBV infection patients
Authors: Shi Y. , Lan Y. , Cao F. , Teng Y. , Li L. , Wang F. , Li J. , Zhou J. , Li Y.
Published: March 2014

A weak T‐cell response plays a key role in the persistence of hepatitis B virus (HBV) infection. We aimed to confirm that T‐cell defects in patients with chronic HBV infection are associated with HBV DNA infection of bone marrow (BM) hematopoietic stem cells (HSCs). Using reverse transcription polymerase chain reaction (RT‐PCR) and fluorescence in situ hybridization (FISH), we observed the transcription of HBsAg coding genes and confirmed the integration of HBV DNA in CD34+ BM HSCs from chronic HBV infection patients. T cells were generated by coculturing the HSCs with delta‐like ligand 1‐expressing OP9 (OP9‐DL1) cells. The phenotypes of the T cells were then evaluated by flow cytometric (FACS) analysis on days 14 and 25. The results demonstrated that fewer CD3+TCRaβ+ CD3+CD4+ and CD4+CD8+ T cells were generated from the HSCs of the patients than from the healthy controls, (P < 0.01) but the frequency of CD3+D8+ T cells was not significantly different between the two group (P > 0.05). In contrast, CD4+CD25+ T cells were more in the patient group than in healthy controls (P < 0.01) on both days 14 and 25. There were fewer CD3+CD4+/CD3+CD8+ cells in the patient group than in the healthy control group on day 25 (P < 0.05). Less proliferation and lower levels of IL‐2 and IFN‐ γ were also observed in the patient group compared with the control group (P < 0.05).These data suggest that HBV DNA infected and integrated into the BM HSCs from patients with chronic HBV infection and that these BM HSCs generated defective T cells.
Albumin infusion improves renal blood flow autoregulation in patients with acute decompensation of cirrhosis and acute kidney injury
Authors: Garcia‐Martinez Rita , Noiret Lorette , Sen Sambit , Mookerjee Rajeshwar , Jalan Rajiv
Published: March 2014

Background & Aims

In cirrhotic patients with renal failure, renal blood flow autoregulation curve is shifted to the right, which is consequent upon sympathetic nervous system activation and endothelial dysfunction. Albumin infusion improves renal function in cirrhosis by mechanisms that are incompletely understood. We aimed to determine the effect of albumin infusion on systemic haemodynamics, renal blood flow, renal function and endothelial function in patients with acute decompensation of cirrhosis and acute kidney injury.

Methods

Twelve patients with refractory ascites and 10 patients with acute decompensation of cirrhosis and acute kidney injury were studied. Both groups were treated with intravenous albumin infusion, 40–60 g/days over 3–4 days. Cardiac and renal haemodynamics were measured. Endothelial activation/dysfunction was assessed using von Willebrand factor and serum nitrite levels. F2α Isoprostanes, resting neutrophil burst and noradrenaline levels were quantified as markers of oxidative stress, endotoxemia and sympathetic activation respectively.

Results

Albumin infusion leads to a shift in the renal blood flow autoregulation curve towards normalization, which resulted in a significant increase in renal blood flow. Accordingly, improvement of renal function was observed. In parallel, a significant decrease in sympathetic activation, inflammation/oxidative stress and endothelial activation/dysfunction was documented. Improvement of renal blood flow correlated with improvement in endothelial activation (r = 0.741, P < 0.001).

Conclusions

The data suggest that albumin infusion improves renal function in acutely decompensated cirrhotic patients with acute kidney injury by impacting on renal blood flow autoregulation. This is possibly achieved through endothelial stabilization and a reduction in the sympathetic tone, endotoxemia and oxidative stress.
The risk of perioperative adverse events in patients with chronic liver disease
Authors: Kim Tae Hyung , Um Soon Ho , Yim Sun Young , Seo Yeon Seok , Yim Hyung Joon , Jeen Yoon Tae , Lee Hong Sik , Chun Hoon Jae , Kim Chang Duck , Ahn Hyonggin , Lee Yeji
Published: March 2014

Background & Aims

Chronic liver disease is a common comorbidity in surgery. To assess post‐operative morbidity and mortality in relation to progression of chronic liver disease and to identify the risk factors.

Methods

Six hundred and nine consecutive patients with chronic liver disease who underwent surgery were classified into two groups: non‐cirrhotic (n = 363) and cirrhotic (n = 246). Randomly selected patients without underlying liver disease who underwent surgery were used as control group (n = 148).

Results

The occurrence of major post‐operative complications was higher in the non‐cirrhotic group than in the control group (11.8% vs. 6.1%, P = 0.051); age, type of surgery and serum albumin level were independent predictors for post‐operative morbidity. The frequency of significant post‐operative liver damage (14.9% vs. 12.2%, P = 0.920) and mortality (0.6% vs. 0.7%, P = 0.871) did not differ between the two groups. The cirrhotic group had markedly higher incidences of post‐operative mortality (10.2%), major complications (32.5%) and significant liver damage (43.1%) than the control and non‐cirrhotic groups (all P < 0.001). Type of surgery, Child–Pugh score and model for end‐stage liver disease score were independently associated with post‐operative morbidity and mortality in patients with cirrhosis. Specific data regarding post‐operative morbidity and mortality were presented according to progression of liver disease and type of surgery.

Conclusion

Non‐cirrhotic chronic liver diseases were associated with higher risk of post‐operative morbidity, particularly in cases of major surgery, older age and hypoalbuminaemia. Cirrhosis further increased the risk, even death, depending on degree of hepatic decompensation and type of surgery.
One image, multiple nationalisms:Face to Faceand theSiege atKanehsatà:ke
Authors: Wilkes Rima , Kehl Michael
Published: March 2014

Iconic news photographs, particularly those taken during wars and national crises, provide visual synopses of important historical events – events about which stories of triumph and tragedy are superimposed. In this paper, we systematically trace the appearances and discussions of a single, iconic image, given the monikerFace to Face, over time. In the twenty plus years since its initial publication, media discourses around the image referenced Kanien'kehaka /Mohawk, Indigenous,Quebecois andCanadian nationalisms. We conclude that discourses surrounding war and conflict imagery can be read as reflecting plural nationalisms and that while a dominant meaning can be projected onto such imagery, this is neither singular nor fixed.
Effectiveness of supine/standing urinalysis for differential diagnosis of left renal vein entrapment syndrome combined with or without glomerulopathy
Authors: Jin Meiling , Hu Panpan , Ding Rui , Chen Pu , Qiu Qiang , Wu Jie , Liu Shuwen , Xie Yuansheng , Chen Xiangmei
Published: March 2014

Aim

To assess the effectiveness of supine/standing urinalysis for differential diagnosis of left renal vein entrapment syndrome (LRVES) combined with or without glomerulopathy.

Methods

The enrolled patients with abnormal urinalysis and LRVES demonstrated by Doppler sonography were guided to perform a supine/standing urinalysis.

Results

Fifty‐two patients were enrolled. Most of them were adolescents (aged 14–29 years, 73.1%) and with low body mass index (BMI, mean BMI, 19.8 ± 2.4 kg/m2). Seventeen cases (32.7%) manifested orthostatic urine abnormalities (OUA, proteinuria and/or haematuria show negative in supine while positive after 15 min standing), two patients who had undergone renal biopsies both showed no evidence of kidney lesions, another two patients were changed from abnormal to normal urinalysis after weight gain. The remaining 35 cases (67.3%) manifested non‐orthostatic urine abnormalities (NOUA, proteinuria and/or haematuria show positive both in supine and standing), 15 patients had undergone renal biopsies and showed different degrees of glomerulopathy. After prednisone/immunosuppression therapy, four patients with glomerulonephritis were changed from the NOUA to the OUA classification. Statistics analyses showed that serum total protein and albumin levels were significantly lower (P = 0.028, 0.007, respectively) and urinary protein was significantly higher (P = 0.007) in the NOUA group than in the OUA group.

Conclusion

After the indication of LRVES by ultrasound, patients with OUA likely have only LRVES, while patients with NOUA likely also have glomerulopathy. Supine/standing urinalysis combined with Doppler sonography can be helpful for differential diagnosis of LRVES combined with or without glomerulopathy.
Factor‐associated caregiver burden in medically complex patients with special health‐care needs
Authors: Yotani Nobuyuki , Ishiguro Akira , Sakai Hirokazu , Ohfuji Satoko , Fukushima Wakaba , Hirota Yoshio
Published: March 2014

Background

Many medically complex patients with special health‐care needs (PSHCN) receive home‐based medical support, placing a major burden on their caregivers. We characterized the caregiving factors involved in PSHCN and their relationship with caregiver burden.

Methods

The PSHCN and their families were recruited from children's hospitals and rehabilitation centers. A medical information handbook was distributed to the families on enrollment, followed by a self‐report questionnaire 1 year later. Data on the type of caregiving involved, family circumstances, and caregiver burden were collected. The Zarit caregiver burden scale (ZS) was used to evaluate caregiver burden. Logistic regression (proportional odds model) was used to determine associations between each variable and caregiver burden in each of two PSHCN age groups: <15 years old (younger group) and ≥15 years (older group).

Results

Sixty‐eight PSHCN and their families were included in the analysis. The mean age of the PSHCN was 15.4 ± 11.8 years. On multivariate analysis there was a significant positive correlation between ZS score and older siblings (odds ratio [OR], 3.65), but no significant correlation between caregiver burden and type of care involved in the younger group. In the older group, a positive correlation was observed between caregiver burden and home mechanical ventilation with tracheostomy (OR, 15.16), but a negative correlation with younger siblings (OR, 0.04).

Conclusions

Family circumstances play a bigger role than type of care required in increasing caregiver burden in families of PSHCN aged less than 15 years.
Chromosome‐specific physical localisation of expressed sequence tag loci in Corchorus olitorius L.
Authors: Joshi A. , Das S. K. , Samanta P. , Paria P. , Sen S. K. , Basu A.
Published: March 2014

Jute (Corchorus spp.), as a natural fibre‐producing species, ranks next only to cotton. Inadequate understanding of its genetic architecture is a major lacuna for genetic improvement of this crop in terms of yield and quality. Establishment of a physical map provides a genomic tool that helps in positional cloning of valuable genes. In this report, an attempt was initiated to study association and localisation of single copy expressed sequence tag (EST) loci in the genome of Corchorus olitorius. The chromosome‐specific association of EST was determined based on the appearance of an extra signal for a single copy cDNA probe in mitotic interphase nuclei of specific trisomic(s) for fluorescence in situ hybridisation, and validated using a cDNA fragment of the 26S rRNA gene (600 bp) as molecular probe. The probe exhibited three signals in meiotic interphase nuclei of trisomic 5, instead of two as observed in diploids and other trisomics, indicating its association with chromosome 5. Subsequent hybridisation of the same probe on the pachytene chromosomes of diploids confirmed that 26S rRNA occupies the terminal end of the short arm of chromosome 5 in C. olitorius. Subsequently, chromosome‐specific association of 63 single copy EST and their physical localisation were determined on chromosomes 2, 4, 5 and 7. The study describes chromosome‐specific physical localisation of genes in jute. The approach used here could be a step towards construction of genome‐wide physical maps for any recalcitrant plant species like jute.
Physical activity in chronic obstructive pulmonary disease: Is it a process or an outcome?
Authors: Benton Melissa J.
Published: March 2014

See article, page 330
Oral ribavirin therapy for respiratory syncytial virus infections in moderately to severely immunocompromised patients
Authors: Marcelin J.R. , Wilson J.W. , Razonable R.R. ,   The Mayo Clinic Hematology/Oncology and Transplant Infectious Diseases Services
Published: March 2014

Background

Respiratory syncytial virus (RSV) infections may be fatal in immunocompromised patients. Aerosolized ribavirin is used for treatment, but it is very costly, teratogenic, and inconvenient. We aimed to assess the outcome of oral ribavirin treatment, with or without intravenous immunoglobulin (IVIG), for RSV infections in moderately to severely immunocompromised patients.

Methods

Medical records of RSV polymerase chain reaction (PCR)‐positive patients during 2011–2013 were reviewed retrospectively. Eligible patients were moderately to severely immunocompromised and received oral ribavirin (600–800 mg twice daily) with or without IVIG (500 mg/kg q 48 h) as per protocol.

Results

Of 96 adults with PCR‐proven RSV infection, 34 were moderately to severely immunocompromised and received oral ribavirin treatment. The mean age was 56.2 years (range: 18–90); 21 were male. Underlying conditions were hematologic malignancy with or without hematopoietic stem cell transplant (n = 25), lung transplant (n = 3), or receipt of cytotoxic chemotherapy (n = 11). The presenting symptoms were cough (94%), fever (62%), and dyspnea (59%). The most common radiographic findings were patchy and nodular infiltrates and opacities. Of 34 patients, 31 were hospitalized, with 13 admitted to the intensive care unit and 6 required mechanical ventilation. The median absolute lymphocyte count on presentation was 480 cells/mm3. RSV pneumonia developed in 24 patients. The median initial duration of oral ribavirin treatment was 10 days (range: 4–11); 4 patients were re‐treated. Of 34 patients, 19 received a mean of 2.7 doses of IVIG. Two patients had adverse reactions to ribavirin (hemolytic anemia and lactic acidosis in 1 patient, and altered mental status in another). No patient died from RSV infection. Three patients died from complications of their underlying illness; all others recovered clinically.

Conclusions

Oral ribavirin with or without IVIG is a well‐tolerated treatment for RSV infection in moderately to severely immunocompromised hosts. Comparative prospective studies should ideally be performed to determine if oral ribavirin is the optimal therapy for RSV infection in this patient population.
Epitope detection chromatography: a method to dissect the structural heterogeneity and inter‐connections of plant cell‐wall matrix glycans
Authors: Cornuault Valérie , Manfield Iain W. , Ralet Marie‐Christine , Knox J. Paul
Published: March 2014

Plant cell walls are complex, multi‐macromolecular assemblies of glycans and other molecules and their compositions and molecular architectures vary extensively. Even though the chemistry of cell‐wall glycans is now well understood, it remains a challenge to understand the diversity of glycan configurations and interactions in muro, and how these relate to changes in the biological and mechanical properties of cell walls. Here we describe in detail a method called epitope detection chromatography analysis of cell‐wall matrix glycan sub‐populations and inter‐connections. The method combines chromatographic separations with use of glycan‐directed monoclonal antibodies as detection tools. The high discrimination capacity and high sensitivity for the detection of glycan structural features (epitopes) provided by use of established monoclonal antibodies allows the study of oligosaccharide motifs on sets of cell‐wall glycans in small amounts of plant materials such as a single organ of Arabidopsis thaliana without the need for extensive purification procedures. We describe the use of epitope detection chromatography to assess the heterogeneity of xyloglucan and pectic rhamnogalacturonan I sub‐populations and their modulation in A. thaliana organs.
Weed–pathogen interactions and elevated CO2: growth changes in favour of the biological control agent
Authors: Shabbir A , Dhileepan K , Khan N , Adkins S W
Published: March 2014

In this study, we used Parthenium hysterophorus and one of its biological control agents, the winter rust (Puccinia abrupta var. partheniicola) as a model system to investigate how the weed may respond to infection under a climate change scenario involving an elevated atmospheric CO2 (550 μmol mol−1) concentration. Under such a scenario, P. hysterophorus plants grew significantly taller (52%) and produced more biomass (55%) than under the ambient atmospheric CO2 concentration (380 μmol mol−1). Following winter rust infection, biomass production was reduced by 17% under the ambient and by 30% under the elevated atmospheric CO2 concentration. The production of branches and leaf area was significantly increased by 62% and 120%, under the elevated as compared with ambient CO2 concentration, but unaffected by rust infection under either condition. The photosynthesis and water use efficiency (WUE) of P. hysterophorus plants were increased by 94% and 400%, under the elevated as compared with the ambient atmospheric CO2 concentration. However, in the rust‐infected plants, the photosynthesis and WUE decreased by 18% and 28%, respectively, under the elevated CO2 and were unaffected by the ambient atmospheric CO2 concentration. The results suggest that although P. hysterophorus will benefit from a future climate involving an elevation of the atmospheric CO2 concentration, it is also likely that the winter rust will perform more effectively as a biological control agent under these same conditions.
Isolation of a Campylobacter lanienae‐like Bacterium from Laboratory Chinchillas (Chinchilla laniger)
Authors: Turowski E. E. , Shen Z. , Ducore R. M. , Parry N. M. A. , Kirega A. , Dewhirst F. E. , Fox J. G.
Published: March 2014

Routine necropsies of 27 asymptomatic juvenile chinchillas revealed a high prevalence of gastric ulcers with microscopic lymphoplasmacytic gastroenteritis and typhlocolitis. Polymerase chain reaction (PCR) analysis using Campylobacter genus‐specific partial 16S rRNA primers revealed the presence of Campylobacter spp. DNA in the faeces of 12 of 27 animals (44.4%). Species‐specific partial 16S rRNA PCR and sequencing confirmed that these animals were colonized with Campylobacter lanienae, a gram‐negative, microaerophilic bacterium that was first identified on routine faecal screening of slaughterhouse employees and subsequently isolated from faeces of livestock. Campylobacter lanienae was isolated from the faeces of six PCR‐positive animals and identified with species‐specific PCR and full 16S rRNA sequencing. Phylogenetic analysis showed that these isolates clustered with C. lanienae strain NCTC 13004. PCR analysis of DNA extracted from gastrointestinal tissues revealed the presence of C. lanienae DNA in the caecum and colon of these chinchillas. Gastrointestinal lesions were scored and compared between C. lanienae‐positive and C. lanienae‐negative animals. There was no correlation between colonization status and lesion severity in the stomach, liver, duodenum, or colon. Possible routes of C. lanienae infection in chinchillas could include waterborne transmission and faecal–oral transmission from wild mice and rats or livestock. Based on these findings, the authors conclude that C. lanienae colonizes the lower bowel of chinchillas in the absence of clinical disease. This is the first report of C. lanienae in any rodent species. Campylobacter lanienae isolates from different mammalian species demonstrate heterogeneity by 16S rRNA sequence comparison. Analysis using rpoB suggests that isolates and clones currently identified as C. lanienae may represent multiple species or subspecies.
The Equal Bending Strength Design of Space Curve Meshing Wheel
Authors: Chen Yang-zhi , Liang Shun-ke , Ding Jiang
Published: March 2014

The space curve meshing wheel (SCMW) has been studied previously for small power transmission. To extend its application in conventional power transmission, the bending strength of the SCMW needs to be studied. In this paper, the tine's section of the SCMW is optimized, the mechanical model of the bending strength is deduced according to the equations for a couple of given contact curves of the SCMW, and the design formulas of the tines are newly deduced based on the equal bending strength principle. Finally, one design example of a SCMW with elliptical torus cross-section tines is provided. The result shows that the theoretical design attained from the presented formulas coincides with that from the finite element analysis. It dedicates that the SCMW possesses enough equal bending strength to be used to in conventional industrial gearing device design.
A Robust Error-Pursuing Sequential Sampling Approach for Global Metamodeling Based on Voronoi Diagram and Cross Validation
Authors: Xu Shengli , Liu Haitao , Wang Xiaofang , Jiang Xiaomo
Published: March 2014

Surrogate models are widely used in simulation-based engineering design and optimization to save the computing cost. The choice of sampling approach has a great impact on the metamodel accuracy. This article presents a robust error-pursuing sequential sampling approach called cross-validation (CV)-Voronoi for global metamodeling. During the sampling process, CV-Voronoi uses Voronoi diagram to partition the design space into a set of Voronoi cells according to existing points. The error behavior of each cell is estimated by leave-one-out (LOO) cross-validation approach. Large prediction error indicates that the constructed metamodel in this Voronoi cell has not been fitted well and, thus, new points should be sampled in this cell. In order to rapidly improve the metamodel accuracy, the proposed approach samples a Voronoi cell with the largest error value, which is marked as a sensitive region. The sampling approach exploits locally by the identification of sensitive region and explores globally with the shift of sensitive region. Comparative results with several sequential sampling approaches have demonstrated that the proposed approach is simple, robust, and achieves the desired metamodel accuracy with fewer samples, that is needed in simulation-based engineering design problems.
A Compliant Translational Mechanism Based on Dielectric Elastomer Actuators
Authors: Huu Nguyen Chuc , Alici Gursel , Mutlu Rahim
Published: March 2014

This paper reports on a linear actuation mechanism in the form of a parallel-crank mechanism (i.e., double-crank mechanism) articulated with two dielectric elastomer actuators working in parallel that are fabricated as a minimum energy structure. This structure is established by stretching a dielectric elastomer (DE) film (VHB4910) over a polyethylene terephthalate (PET) frame so that the energy released from the stretched DE film is stored in the frame as bending energy. The mechanism can output a translational motion under a driving voltage applied between two electrodes of the DE film. We have proposed visco-elastic models for the DE film and the frame of the actuator so that the mechanical properties of the actuator can more accurately be incorporated into the mechanism model. The proposed model accurately predicts the experimental frequency response of the mechanism at different voltages. In addition, an inversion-based feedforward controller was successfully implemented in order to further validate the proposed model for sensorless position control of the actuators and the parallel-crank mechanism articulated with these actuators.
Kinetic Shapes: Analysis, Verification, and Applications
Authors: Handz̆ić Ismet , Reed Kyle B.
Published: March 2014

A circular shape placed on an incline will roll; similarly, an irregularly shaped object, such as the Archimedean spiral, will roll on a flat surface when a force is applied to its axle. This rolling is dependent on the specific shape and the applied force (magnitude and location). In this paper, we derive formulas that define the behavior of irregular 2D and 3D shapes on a flat plane when a weight is applied to the shape's axle. These kinetic shape (KS) formulas also define and predict shapes that exert given ground reaction forces when a known weight is applied at the axle rotation point. Three 2D KS design examples are physically verified statically with good correlation to predicted values. Motion simulations of unrestrained 2D KS yielded expected results in shape dynamics and self-stabilization. We also put forth practical application ideas and research for 2D and 3D KS such as in robotics and gait rehabilitation.
Extended Kalman Filter Based In-Cylinder Temperature Estimation for Diesel Engines With Thermocouple Lag Compensation
Authors: Chen Song , Yan Fengjun
Published: March 2014

The in-cylinder temperature information is critical for auto-ignition combustion control in diesel engines, but difficult to be directly accessed at low cost in production engines. Through investigating the thermodynamics of Tivc, cycle-by-cycle models are proposed in this paper for the estimation of in-cylinder temperature at the crank angle of intake valve closing (IVC), referred to as Tivc. An extended Kalman filter (EKF) based method was devised by utilizing the measurable temperature information from the intake and exhaust manifolds. Due to the fact that measured temperature signals by typical thermocouples have slow responses which can be modeled as first-order lags with varying time-constants, temperature signals need to be reconstructed in transient conditions. In the proposed EKF estimation method, this issue can be effectively addressed by analyzing the measurement errors and properly selecting the noises covariance matrices. The proposed estimation method was validated through a high-fidelity GT-power engine model.
Modeling and Experimental Validation of the Effective Bulk Modulus of a Mixture of Hydraulic Oil and Air
Authors: Gholizadeh Hossein , Bitner Doug , Burton Richard , Schoenau Greg
Published: March 2014

It is well known that the presence of entrained air bubbles in hydraulic oil can significantly reduce the effective bulk modulus of hydraulic oil. The effective bulk modulus of a mixture of oil and air as pressure changes is considerably different than when the oil and air are not mixed. Theoretical models have been proposed in the literature to simulate the pressure sensitivity of the effective bulk modulus of this mixture. However, limited amounts of experimental data are available to prove the validity of the models under various operating conditions. The major factors that affect pressure sensitivity of the effective bulk modulus of the mixture are the amount of air bubbles, their size and the distribution, and rate of compression of the mixture. An experimental apparatus was designed to investigate the effect of these variables on the effective bulk modulus of the mixture. The experimental results were compared with existing theoretical models, and it was found that the theoretical models only matched the experimental data under specific conditions. The purpose of this paper is to specify the conditions in which the current theoretical models can be used to represent the real behavior of the pressure sensitivity of the effective bulk modulus of the mixture. Additionally, a new theoretical model is proposed for situations where the current models fail to truly represent the experimental data.
Role of Vasomotion in Control of Retina Edema in Diabetic Retinopathy: Quantification of Fluid Transport Through Retinal Capillaries
Authors: Zhu Liang , Flower Robert
Published: March 2014

Diabetic retinopathy refers to diabetes-related complications in the retina, It is a progressive disease and its symptoms in the eyes can vary from non-vision threatening to vision loss, and it can lead to permanent damage to the neuronal retinal tissue. The irreversible nature of the damage suggests that prevention of diabetes by eliminating risk factors and early screening are the cornerstone of relevant treatment to stop or limit visual damage in those patients.
Apolipoprotein A-I Mimetic Peptide Retains Function After Oxidant Exposure
Authors: Wake Amanda K. , Datta Geeta , Palgunachari Mayakonda N. , Mishra Vinod K. , Anantharamaiah G. M. , White C. Roger
Published: March 2014

Mechanical integrity of arteries is vital for maintaining compensatory mechanisms under physiologic conditions, and changes in vessel structure (and consequently, vessel mechanical properties) are hallmarks of the progression of pathologic states. Oxidative stress can (1) induce endothelial dysfunction by interfering with nitric oxide (NO) signaling pathways relevant to vasodilation/vasoconstriction of arteries, and (2) alter atherosclerotic plaque composition by oxidation of constituents or by interruption of reverse cholesterol transport from plaques.
A Single Cycle Study of Screw Fixation in Anterior Cruciate Ligament Reconstruction
Authors: Chizari M. , Wang B. , Snow M.
Published: March 2014

The natural history of Anterior Cruciate rupture is one of progressive deterioration of knee function, with the development of instability, meniscal tears and post traumatic osteoarthritis. The current surgical approach is for anatomical reconstruction using a biological tissue autograft. It is well understood that the initial stability is dependent on the strength of the fixation rather than the strength of the graft, until the graft becomes biologically incorporated in the bone tunnel. A study was carried out to better understand postoperative internal bone stresses in anterior cruciate ligament (ACL) reconstruction surgery. The mechanical aspects of an interface screw fixation were examined both experimentally and numerically, with the aim to minimize deleterious effects in ACL reconstruction. The tibial cortical/cancellous bony tunnel and the stress pattern resulting from the screw fixation in the tunnel are investigated.
Assessment of Abdominal Aortic Aneurysm Risk: Asymmetry as an Additional Diagnostic Tool?
Authors: Doyle Barry J. , Callanan Anthony , Walsh Michael T. , Vorp David A. , McGloughlin Timothy M.
Published: March 2014

An abdominal aortic aneurysm (AAA) can be defined as a permanent and irreversible localised dilation of the infrarenal aorta. This localised dilation is a result of a degradation of the elastic media of the arterial wall. This degradation of the aortic wall can be attributed to risk factors such as tobacco smoking, sex, age, hypertension, chronic obstructive pulmonary disease, hyperlipidaemia, and family history of the disorder [1]. With the recent advancements in medicine, more AAAs are being detected than ever. Approximately 500,000 new cases are diagnosed each year worldwide resulting in 15,000 deaths per year in the USA alone [2]. Currently, the rupture risk of AAAs is regarded as a continuous function of aneurysm size, with surgical intervention decided based on the maximum diameter of the AAA. Most AAA repairs are performed when the diameter exceeds 50–60mm. It has been shown that maximum diameter may not be a reliable predictor of rupture, as smaller AAAs can also rupture. It is believed by many researchers that there is a need to review the determination of the timing of surgical intervention based solely on aneurysm diameter, and include other relevant risk factors. These additional risk factors could, for example, include, AAA wall stress, AAA expansion rate, degree of asymmetry, presence of intraluminal thrombus (ILT), and hypertension. The addition of these parameters may aid the surgical decision-making process. Shifting the current trend towards more encompassing assessment of AAA rupture potential may help reduce the morbidity and mortality rates associated with AAA repair. It was previously reported [3] that 82% of AAA ruptures occur on the posterior wall. In this research, the asymmetry of the AAA is examined, with respect to both peak wall stress and posterior wall stress, in ten realistic cases, and a resulting threshold factor is presented.
A Hyperelastic Contact Model for the Indentation of Chondrocytes and Cartilage Extracellular Matrix
Authors: Lin David C. , Shreiber David I. , Dimitriadis Emilios K. , Horkay Ferenc
Published: March 2014

The use of micro and nanoindentation to map the elasticity of cartilage chondrocytes and extracellular matrix has been driven by the desire to understand the changes in microstructure and micromechanical properties of the tissue associated with development and with diseases such as osteoarthritis. Advances in atomic force microscopy (AFM) have facilitated application of the technique to soft tissues, allowing the concurrent imaging and mechanical probing of minute sample regions at high resolution. Examples of the capabilities of the AFM in studying cartilage biomechanics include its use in investigating changes in the elastic properties of the articular surface during development [1], comparing the dynamic elastic response at the microscale and the nanoscale [2], and measuring the elastic moduli of different zones [3].
Influence of Inlet Secondary Curvature on Image-Based CFD Models of the Carotid Bifurcation
Authors: Lee Sang-Wook , Steinman David A.
Published: March 2014

In image-based CFD modelling of carotid bifurcation hemodynamics, it is often not possible (or at least not convenient) to impose measured velocity profiles at the common carotid artery (CCA) inlet. Instead, fully-developed velocity profiles are usually imposed based on measured flow rates. Previous work from our group showed that this is reasonable [1], in the sense that errors made in doing so are substantially less than uncertainties inherent in the model construction process itself. In that study, long helical inlet sections were imposed to induce asymmetric (Dean-type) velocity flows profiles consistent with in vivo velocity profiles measured by others at the CCA [2, 3].
The Effect of Varying the Density-Modulus Relationship Used to Apply Material Properties in a Finite Element Model of the Distal Ulna
Authors: Austman Rebecca L. , Milner Jaques S. , Holdsworth David W. , Dunning Cynthia A.
Published: March 2014

In many areas of orthopaedic biomechanics, such as implant design, properly developed Finite Element (FE) models can be a great companion to in-vitro studies, as they may allow a wider range of experimental variables to be explored in a cost-effective and timely manner. One challenge in developing these models is the assignment of accurate material properties to bone. Through the use of computed tomography (CT), many recent studies have developed subject-specific FE models, where material properties of bone are assigned based on density information derived from the scans. This involves the use of an equation to relate density and elastic modulus. There are several such relationships from which to choose in the literature. Most FE studies tend to use one of these multiple equations without justification or investigation into its appropriateness for the model.
Prediction of Human Posture and Movement by Musculoskeletal Optimization
Authors: Rasmussen John
Published: March 2014

Attempts to simulate the human body as a mechanical system traditionally fall into one of two categories, inverse dynamics and forward dynamics, which, as the names indicate, are opposite approaches. The former is sometimes misleadingly termed “static optimization”.
Application of an Optimization-Based Method for the Kinematic Analysis of a Badminton Stroke From Motion Capture Data
Authors: Andersen Michael S. , Kwan Maxine , Damsgaard Michael , Rasmussen John
Published: March 2014

In this paper, we demonstrate an optimization-based method for the calculation of positions, velocities, and accelerations of a badminton stroke from motion capture data. The results show a good agreement between the measured marker trajectories and a flexible kinematical model of the racket with the error between the measured marker trajectories and the markers in the model being in the range of millimeters.
Secondary Stability of a Composite Biomimetic Cementless Hip Stem
Authors: Caouette Christiane , Bureau Martin N. , Yahia L’Hocine
Published: March 2014

Total hip replacement is one of the most successful and frequent surgery in the world; over a million of these procedures are performed every year, and the numbers are growing with the ageing of the general population. The patients who receive these implants also are younger nowadays. Major problems however still subsist with traditional hip stems: aseptic loosening is a common cause of revision surgery. The main causes of aseptic loosening are both mechanical and biological in origin. Mechanical causes include stress shielding and micromotions at bone-implant interface, and biological causes are mainly osteolysis triggered by wear debris formation and bone remodeling. To remedy the mechanical issues, a biomimetic concept was developed (patent pending): an osseointegrated stem with mechanical properties close to those of the surrounding bone would avoid both stress shielding and micromotions phenomena. To evaluate this concept, a finite element model (FEM) was developed and used to simulate bone resorption, stress shielding and micromotions [1]. The preliminary results were promising as those problems were significantly reduced with the new prosthesis, but the model still remained to be proved accurate; its bone-implant interface was of particular interest because of its decisive influence on micromotions.
A Novel Technique for Measuring Pedicle Screw Forces In Situ
Authors: Tia Samuel Q. , Buckley Jennifer M. , Nguyen Thuc-Quyen , Lotz Jeffrey C. , Burch Shane
Published: March 2014

Long posterior fusion constructs in the lumbar spine cause substantial posteriorly directed loading of the supporting pedicle screws, particularly during patient bending activities. Although there are numerous documented accounts of clinical failure at the pedicle screw-bone interface [1,2], the in situ pull-out strength of pedicle screws in long surgical constructs has not been characterized. Previous biomechanical studies have quantified pedicle screw pull-out force in cadaveric models through destructive testing or in nondestructive cases, through the use of custom-machined pedicle screws instrumented with strain gages [3–6]. However, these techniques involve altering screw geometry and may fail to properly simulate in vivo mechanical loading conditions. The goal of this study was to develop and validate a sensor system for measuring pedicle screw pull-out forces in long posterior constructs in situ during multi-segmental cadaveric testing.
Semi-Automated Hexahedral Mesh Generation of Human Vertebrae by Isoparametric Mapping
Authors: Dai Yifei , Niebur Glen L.
Published: March 2014

Subject-specific finite element models provide a means to explore inter-subject biomechanical variations, and have been widely used in the study of spinal fusion such as stress-shielding due to spinal instrumentation [1], and to assess biomechanical response to aging and disease [2–4]. Three-dimensional finite element models of vertebrae are usually constructed from CT scans. However, manual generation of meshes is labor intensive. As such, techniques that simplify creation of meshes are needed to make finite element analysis more feasible for large biomechanical studies and clinical applications.
Mechanical Validation of Computed Tomographic Quantification of Posterolateral Intertransverse Lumbar Fusion
Authors: O’Brien Michael , Dai Yifei , Niebur Glen L.
Published: March 2014

The New Zealand White (NZW) rabbit is often used as an animal model in posterolateral intrertransverse lumbar fusions [1]. Qualitative measures, such as manual palpation and radiographs, have been used to assess fusion mass [1]. However, an evaluation by sacrifice and biomechanical testing is the gold standard for quantitative data. A non-invasive approach to quantitatively assess the mechanics of spinal fusion could allow longitudinal studies with decreased need for animal sacrifice.
Quantification of the Deformation of the Human Iliac Arteries With Hip and Knee Flexion: Implications for Stent-Graft Design
Authors: Choi Gilwoo , Shin Lewis K. , Taylor Charles A. , Cheng Christopher P.
Published: March 2014

Abdominal aortic aneurysm stent grafts have been reported to fracture at a rate as high as 8% [1]. Iliac artery deformation induced by cardiac pulsation or musculoskeletal motions has been hypothesized to cause these fractures, but little in vivo data has been available heretofore to test this hypothesis. We have utilized magnetic resonance angiography and image-processing methods to quantify in vivo deformation of the human iliac arteries due to maximal hip flexion.