bluuebunny/crossref_metadata_2025 huggingface dataset:
High‐molecular‐weight kininogen cleavage correlates with disease states in the bradykinin‐mediated angioedema due to hereditary C1‐inhibitor deficiency
Authors: Suffritti C. , Zanichelli A. , Maggioni L. , Bonanni E. , Cugno M. , Cicardi M.
Published: February 2014

Background

The inherited deficiency of C1‐inhibitor (C1‐INH), which can be quantitative (type I) or qualitative (type II), is characterized by recurrent attacks of oedema, and it is known as hereditary angioedema due to C1‐INH deficiency (HAE‐C1‐INH). The frequency of symptoms varies widely among patients and in the same patient during life.

Objective

To identify laboratory markers of disease severity in HAE‐C1‐INH patients.

Methods

We studied 162 patients with differently severe HAE‐C1‐INH during remission, 31 HAE‐C1‐INH patients during attacks, and 81 normal controls, evaluating complement parameters, spontaneous plasma kallikrein activity, the capacity of plasma to inhibit exogenous kallikrein activity, and cleavage of high‐molecular‐weight kininogen (HK). Sixty‐five HAE‐C1‐INH patients were screened for mutations in the C1‐INH gene.

Results

As expected, plasma C1‐INH levels and activity and C4 levels were low in the HAE‐C1‐INH patients. Spontaneous plasma kallikrein activity in patients in remission was higher than in controls (P = 0.001) and increased during acute attacks (P = 0.01), whereas the capacity of inhibiting kallikrein activity was lower in patients in remission than in controls (P = 0.001) and further reduced during attacks (P = 0.001). HAE‐C1‐INH patients in remission had higher levels of cleaved HK than controls (P = 0.001), and these further increased during acute attacks (P = 0.001). Cleaved HK levels were higher in highly symptomatic HAE‐C1‐INH patients than in those with less frequent attacks (P = 0.001). Thirty‐five different mutations in the C1‐INH gene were equally distributed in patients with different attack frequencies.

Conclusions

Measuring plasma levels of cleaved HK may be a sensitive mean of assessing disease severity in HAE‐C1‐INH patients.
Impact of bone graft harvesting techniques on bone formation and graft resorption: a histomorphometric study in the mandibles of minipigs
Authors: Saulacic Nikola , Bosshardt Dieter D. , Jensen Simon S. , Miron Richard J. , Gruber Reinhard , Buser Daniel
Published: February 2014

Background

Harvesting techniques can affect cellular parameters of autogenous bone grafts in vitro. Whether these differences translate to in vivo bone formation, however, remains unknown.

Objective

The purpose of this study was to assess the impact of different harvesting techniques on bone formation and graft resorption in vivo.

Material and methods

Four harvesting techniques were used: (i) corticocancellous blocks particulated by a bone mill; (ii) bone scraper; (iii) piezosurgery; and (iv) bone slurry collected from a filter device upon drilling. The grafts were placed into bone defects in the mandibles of 12 minipigs. The animals were sacrificed after 1, 2, 4 and 8 weeks of healing. Histology and histomorphometrical analyses were performed to assess bone formation and graft resorption. An explorative statistical analysis was performed.

Results

The amount of new bone increased, while the amount of residual bone decreased over time with all harvesting techniques. At all given time points, no significant advantage of any harvesting technique on bone formation was observed. The harvesting technique, however, affected bone formation and the amount of residual graft within the overall healing period. Friedman test revealed an impact of the harvesting technique on residual bone graft after 2 and 4 weeks. At the later time point, post hoc testing showed more newly formed bone in association with bone graft processed by bone mill than harvested by bone scraper and piezosurgery.

Conclusions

Transplantation of autogenous bone particles harvested with four techniques in the present model resulted in moderate differences in terms of bone formation and graft resorption.
Extraocular well‐differentiated sebaceous tumors with overlying cutaneous horns: four tumors in three patients
Authors: Jhuang Jie‐Yang , Liao Shu‐Lang , Tsai Jia‐Huei , Chang Hsiao‐Ching , Kuo Kuan‐Ting , Liau Jau‐Yu
Published: February 2014

Background

Sebaceous tumors are adnexal neoplasms showing sebocytic differentiation. They range from benign to malignant and are associated with Muir‐Torre syndrome (MTS). Several clinical and histopathological features associated with MTS have been described. Sebaceous tumors with an overlying cutaneous horn are extremely rare.

Methods

Hematoxylin and eosin‐stained slides were retrospectively reviewed to identify sebaceous tumors with marked hyperkeratosis, a condition that is often associated with cutaneous horns. Clinical correlation and mismatch repair protein immunohistochemical studies were then conducted.

Results

Four tumors from three patients were identified in our archive. Three were classified as sebaceous adenomas, and the fourth was considered as a borderline sebaceous tumor favoring well‐differentiated sebaceous carcinoma. All cases showed loss of expression of mismatch repair proteins (three tumors from two patients exhibited lost expression of MSH2 and MSH6, and the fourth exhibited lost expression of MLH1 and PMS2). Additionally, one patient presented characteristic clinical manifestations of MTS, including multiple sebaceous adenomas and visceral carcinomas.

Conclusions

We suggest that extraocular well‐differentiated sebaceous neoplasms with overlying cutaneous horns may be an indication of underlying mismatch repair protein deficiency and potential MTS. This distinctive morphology might be an exaggerated combination of other features associated with MTS, i.e. keratoacanthoma‐like architecture and extensive holocrine secretion.
Lgbti Discrimination and Parent–Child Relationships: Cross‐Border Mobility of Rainbow Families in the European Union
Authors: Falletti Elena
Published: February 2014

One of the most critical issues in the landscape of the member states of the European Union is the recognition in other countries of the parent–child relationship within “rainbow” families. The parenthood of partners of same‐sex couples is acknowledged in Spain, Sweden, Denmark, Belgium, and the Netherlands. In other countries laws offer timid and partial protection against discrimination of the children of same‐sex couples. In the majority of countries, however, there is still no legislative provision recognizing and protecting a child's relationship with one of the partners of a same‐sex relationship. This legal fragmentation threatens freedom of movement within the European Union and challenges the principle of discrimination between children only on the basis of the sexual orientation of the partners in the family. By scrutinizing the distortion of the framework of fundamental rights as recognized within the European Union, and by raising the awareness that European citizenship includes a new dimension of individuals' protection, this article will investigate political and juridical issues in relation to the implementation of children's rights and mutual recognition between the states.

Keypoint

The innovation of the approach offered in this article lies in the mutual recognition of the forms of protection and on the study of the available case law at the European level. The analysis will be aimed to the fundamental protection of children and to the enforcement of all the measures which are necessary for the full protection of the best interests of the children.
What is Good Parenting? The Perspectives of Different Professionals
Authors: Eve Philippa M. , Byrne Mitchell K. , Gagliardi Cinzia R.
Published: February 2014

Defining parenting, and good parenting in particular, is a complex task wrought with ambiguities. This creates problems in agreeing on a standard parenting capacity assessment, particularly in relation to strengths as opposed to weaknesses. To address this lack of consensus, the current study explored the convergence and divergence of different professional groups' opinions on good parenting. A mixed‐methods design was employed, with semi‐structured interviews and rating scales administered to 19 professionals with experience in parenting capacity assessments. Data were analyzed using a constructivist grounded theory. The findings suggest that, in general, professionals agree on main themes of good parenting, including (1) insight, (2) willingness and ability, (3) day‐to‐day versus complex/long‐term needs, (4) child's needs before own, (5) fostering attachment, and (6) consistency versus flexibility. Within these six categories, individual differences emerged. Theoretical and practical implications are discussed.

Keypoints

Describes the importance of parenting capacity Assessments and the variances in practitioner approaches

Adopts a strengths based approach as an adjunct to the traditional deficits based approach to Parenting capacity assessments

Contextualises the key decision making issues affecting assessors and decision makers in the judicial system

Provides a theoretical model on decision makers opinions regarding good parenting and outlines directions for the development of strengths based assessments as a contribution to child placement decisions
Involvement of platelets in extrahepatic metastasis of hepatocellular carcinoma
Authors: Morimoto Yuki , Nouso Kazuhiro , Wada Nozomu , Takeuchi Yasuto , Kinugasa Hideaki , Miyahara Koji , Yasunaka Tetsuya , Kuwaki Kenji , Onishi Hideki , Ikeda Fusao , Miyake Yasuhiro , Nakamura Shinichiro , Shiraha Hidenori , Takaki Akinobu , Yamamoto Kazuhide
Published: February 2014

Aim

Recently, a relationship between platelets and cancer metastasis has been reported. The aim of this study is to elucidate the risk factors for extrahepatic metastasis (EHM), with emphasis on association with platelets in patients, with hepatocellular carcinoma (HCC).

Methods

We examined risk factors for EHM in 1613 consecutive, newly diagnosed HCC patients by logistic regression analysis (case–control study). We also examined the factors by Cox proportional hazard model in a retrospective cohort fashion in 803 patients who received non‐curative treatment for HCC.

Results

In the case–control study, multivariate analysis revealed that high platelet counts (odds ratio [OR] = 4.84; 95% confidence interval [CI] = 1.29–29.54; P = 0.01), high tumor number and the presence of macroscopic vascular invasion were significantly associated with EHM. In the cohort study, EHM was diagnosed in 71 patients during the study period (mean observation time = 23.3 months). On multivariate analysis, high tumor number, high des‐γ‐carboxyprothrombin (DCP) and Child–Pugh class A were significantly correlated with EHM, and the patients with high platelet counts tended to develop EHM (OR = 1.73; 95% CI = 0.99–3.14; P = 0.055).

Conclusion

HCC patients with high platelet counts, as well as large numbers of tumors, high serum DCP and Child–Pugh class A, are at risk for EHM.
Resting Energy Expenditure and Systolic Blood Pressure Relationships in Women Across 4.5 Years
Authors: Sriram Neeraj , Hunter Gary R. , Fisher Gordon , Brock David W.
Published: February 2014

Recent studies have reported a strong association between blood pressure (BP) and resting energy expenditure (REE). However, it is not known whether this relationship persists over time. Therefore, the authors examined the temporal relationship between REE and systolic BP. In addition, the impact of sympathetic tone and anthropometric variables on this relationship was examined. All testing was performed on healthy, overweight African American and European American women aged 25 to 45 years over 4.5 years in the University of Alabama at Birmingham General Clinical Research Center. Repeated‐measures mixed‐models revealed REE as a significant determinant of systolic BP (β=0.0155, P<.0001), independent of catecholamines, leg fat, visceral fat, fat‐free mass, fat mass, height, relative skeletal muscle index, and resting heart rate. Observations that REE is predictive of systolic BP across 4.5 years support previous findings that REE may potentially mediate resting BP, independent of anthropometric variables and a marker for sympathetic tone.
Changes in Physical and Dielectrical Properties of Carp Meat (Cyprinus Carpio) during Cold Storage
Authors: Ochrem Andrzej Stanisław , Zapletal Piotr , Maj Dorota , Gil Zygmunt , Żychlińska‐Buczek Justyna
Published: February 2014

Research carried out on gutted and ungutted carps showed changes in physical and dielectrical properties during storage under refrigerated conditions. During the research, quality index scheme for carp was developed. In the conducted experiment, statistically significant (P ≤ 0.05) differences in pH values between the gutted and ungutted fish, and between successive days in both groups, were not observed. Within 10 days of storage of the carps in refrigerated conditions, the Torrymeter values were steadily decreasing. Based on the results, the equations were set. Conductivity and electrical resistance were significantly correlated with Torrymeter readings on the head, tail and belly.

Practical Applications

This work addresses the evaluation of the freshness of a carp (Cyprinus carpio) meat. Simple, quick and accurate methods have been proposed. Consumers and traders were able to monitor the quality of fish fillets during refrigeration storage using Torrymeter and QIM (quality index method), measurement of electrical resistance.
To Say or not to Say: Dyadic Ambivalence over Emotional Expression and Its Associations with Pain, Sexuality, and Distress in Couples Coping with Provoked Vestibulodynia
Authors: Awada Nayla , Bergeron Sophie , Steben Marc , Hainault Victoria-Ann , McDuff Pierre
Published: February 2014

Introduction

Provoked vestibulodynia (PVD) is a highly prevalent and taxing female genital pain condition. Despite the intimate nature of this pain and the fact that affective factors such as anxiety have been shown to modulate its manifestations, no study has yet explored the emotional regulation of couples in which the woman suffers from PVD.

Aim

Ambivalence over emotional expression (AEE) is an emotional regulation variable that quantifies the extent to which a person is comfortable with the way she or he expresses emotions. We examined whether the dyadic AEE of couples in which the woman suffers from PVD was differentially associated with women's pain and couples' psychological, sexual, and relational functioning.

Methods

Couples (N = 254), in which the woman suffered from PVD, completed the AEE questionnaire. A couple typology of dyadic AEE was created.

Main Outcome Measures

Dependent measures for both members of the couple were the global measure of sexual satisfaction scale, the Beck depression inventory II, and the revised dyadic adjustment scale. The female sexual function index and the sexual history form were used to assess the sexual function of women and men, respectively. Women also completed the pain rating index of the McGill pain questionnaire.

Results

Couples, in which both partners were considered low on AEE, had the highest scores on sexual satisfaction (P = 0.02) and function (P < 0.01), the lowest depression scores (P < 0.01), and the best dyadic adjustment (P = 0.02). No difference in pain intensity was found between couples.

Conclusions

Findings suggest that, for couples in which the woman suffers from PVD, an emotional regulation that is low in ambivalence in both partners is associated with better psychological, sexual, and relational outcomes. Results indicate that emotional regulation may be important to consider in the assessment and treatment of couples coping with PVD.
Efficacy of bronchial fiberscope in esophageal fistula caused by necrotizing bronchitis
Authors: Matsui Jun , Nakahara Sayuri , Kikuoka Nanae , Tsutsui Hidemi , Furukawa Ouki , Kitamura Shoji , Yanagi Takahide , Koshida Shigeki , Hasegawa Hisaya
Published: February 2014

Neonatal necrotizing bronchitis is a disease that occurs in premature and low‐birthweight infants who are subject to artificial respiratory management, and which has a poor prognosis, because it progresses suddenly and can result in death. There have been no reports of survival to date in cases of tracheo‐esophageal fistula caused by necrotizing bronchitis, and no swift and effective management method has yet been reported. This report describes a case in which the use of a bronchial fiberscope in making an early diagnosis facilitated appropriate management and survival. The proactive use of a bronchial fiberscope in regard to this disease, which has a high fatality rate, may save lives.
Non‐invasive renal artery embolization for renal dysplasia accompanied by hypertension
Authors: Yanagida Hidehiko , Tabata Nobutada , Sugimoto Keisuke , Izu Akane , Wada Norihisa , Sakata Naoki , Okada Mitsuru , Takemura Tsukasa
Published: February 2014

Renovascular hypertension caused by renal dysplasia often is resistant to drug therapy. For a 14‐year‐old girl with such refractory hypertension, a non‐invasive right renal ablation by embolization with anhydrous ethanol using a shepherd ‘s‐crook’ balloon catheter, was done. Blood pressure then rapidly normalized. Apart from mild fever after the procedure, no adverse effects occurred. In patients with mild renal artery stenosis and hypertension resistant to anti‐hypertensive drug therapy, renal artery embolization may be a useful option.
Pulmonary veno‐occlusive disease in an 11‐year‐old girl: Diagnostic pitfalls
Authors: Kano Gen , Nakamura Keiko , Sakamoto Izumi
Published: February 2014

Pulmonary veno‐occlusive disease (PVOD) is a rare chronic lung disease that is difficult to diagnose due to non‐specific clinical findings. Little is known about the pathogenesis of PVOD. Reported herein is the case of an 11‐year‐old girl who initially presented with ‘bat‐wing’ shadows on chest radiography. This finding, coupled with prominent hemosiderosis in bronchoalveolar lavage fluid, initially led to a misdiagnosis of idiopathic pulmonary hemosiderosis. Oral prednisolone dramatically improved signs and symptoms initially, but her condition then gradually deteriorated during maintenance therapy with corticosteroids and other immunosuppressants. PVOD was suspected but not confirmed owing to a lack of hallmark radiographic findings and contraindications for lung biopsy. Three years later, while arranging for lung transplantation, the patient experienced sudden onset of fatal massive pulmonary edema. PVOD was confirmed at autopsy. This case provides insights regarding an unfamiliar presentation of PVOD and may help physicians to avoid diagnostic pitfalls.
Local Cost Surface Models of Distance Decay for the Analysis of Gridded Population Data
Authors: Lloyd Christopher D.
Published: February 2014

The paper evaluates some proposed improvements to the analysis of gridded population data, using as a case-study the religious segregation that is observed in gridded population data from Northern Ireland: first, the use of cost surfaces rather than simple Euclidean (straight line) distances to represent the interactions between gridded geographic areas; second, a method for creating gridded cost surfaces that takes account of vector features (such as roads and physical obstructions); third, the limitation of cost surfaces to a tightly defined ‘local’ set of areas, with a view to reduce computational overheads significantly without adversely impacting the accuracy of subsequent results. The results suggest that all three improvements have merit. The paper further explores the effect of using log-ratios rather than percentages (minimal) and of local rather than global measures of segregation (which allows for considerably greater insight into population characteristics). Although the case-study and results apply specifically to gridded population data, the results of the paper have wider implications for the analysis of any type of zonal data.
Development of a New Artificial Knee Joint for an Asian and Middle Eastern Population
Authors: Ranu Harcharan Singh
Published: February 2014

Design of an artificial knee was developed using computer 3-D modeling, the high flexion knee was obtained by using a multi-radii design pattern, The increase of final 20 degrees in flexion was obtained by increasing the condylar radii of curvature. The model of the high flexion knee was developed and one of the models was subjected to finite element modeling and analysis.

The compositions of components in the artificial knee were, femoral component and the tibial component were metal, whereas the patellar component and the meniscal insert were made using polyethylene. The metal component used for the analysis in this study was Ti6Al4V and the polyethylene used was UHMWPE. Overall biomaterials chosen were: meniscus (UHMWPE, mass = 0.0183701 kg, volume = 1.97518e-005 m3), tibial component (Ti6Al4V, mass = 0.0584655 kg, volume = 1.32013e-005 m3), femoral component (Ti6Al4V, mass = 0.153122 kg, volume = 3.45742e-005 m3), total artificial assembly (mass = 0.229958 kg, volume = 6.75e-005m3).

However, in this design the load had been taken to 10 times the body weight. The weight over single knee is only half the maximum load as the load is shared between the two knee joints. Following were the loading conditions, taking average body weight to be 70Kgs and taking extreme loading conditions of up to 10 times the body weight, i.e. 700Kgs on each of the leg performed the Finite Element Analysis (FEA) over the newly designed knee. The loading was done at an increment of 100 Kgs. The loading conditions and the meshing details for the analysis of the assembly were Jacobian check: 4 points, element size: 0.40735 cm, tolerance: 0.20367 cm, quality: high, number of elements: 80909, number of nodes: 126898. A maximum load of 600 Kgs is optimum for this model. The other components observed linear elastic behavior for the applied loads. Based on these results it was determined that the load bearing capacity of the model were well within the failure levels of the materials used for the analysis. A maximum load of 600 Kgs is optimum for this model. The other components observed linear elastic behavior for the applied loads. Based on these results it was determined that the load bearing capacity of the model were well within the failure levels of the materials used for the analysis.

Conclusion drawn from this is that for the first time an innovative new design of an artificial knee joint to suite a segment of some religious population has been developed. This allows them to pray, bend in different positions and squat without too much difficulty.
Patient-Specific Computational Abdominal Wall Modeling: Application to Mid-Line Laparotomy Closure
Authors: Belzacq Tristan , Nováček Vít , Guérin Gaëtan , Tran Doris , Mitton David , Turquier Frédéric
Published: February 2014

A patient-specific computational finite element modeling of the abdominal wall (AW) has been developed to enable biomechanical analysis for customizing and optimizing AW surgical treatments. The methodology consisted on the identification by reverse engineering of patient-specific AW characteristics for physiological pressure settings. The approach combined in vivo experiments and numerical simulations. As a first application, a patient specific model was used to simulate mid-line incision closure technique.
Committee on Credible Practice of Modeling and Simulation in Healthcare
Authors: Mulugeta Lealem , Erdemir Ahmet
Published: February 2014

Leading health institutions, government agencies, education and research institutions, as well as medical product developers around the world have recognized the substantial potential of computational modeling and simulation (M&S) to support clinical research and decision making in healthcare, e.g., [1]. Consequently, research activities in computational medicine are growing at a significant rate and notable discoveries are being made [2]. However, the mechanisms or processes necessary to appropriately translate these research activities and discoveries in computational methods to clinical practice are lacking. Moreover, there is substantial research diversity in the field such that subject matter experts within and across mathematical and biological disciplines tend to have their own interpretation of credible practice in M&S [3–5]. Additionally, tools and good practice guidelines established by individual disciplines or research areas do not readily transfer across other disciplines or are not adopted by different fields.
Cadaveric Evaluation of Soft-Tissue Constraint in the Human Knee
Authors: Cyr Adam , Maletsky Lorin
Published: February 2014

The motion patterns of the human knee joint depend on its passive motion characteristics, which are described by the ligamentous and articular constraints. Since active motions, like walking and squatting are believe to fall within a passive envelope, the basis for the understanding of the knee joint kinematics lies in the description of its passive characteristics.
Using 3D Modeling and Neural Networks to Predict Time-to-Heal for Chronic, Non-Healing Wounds
Authors: Chin Jessica S. , Zeid Ibrahim , Kamarthi Sagar
Published: February 2014

Chronic, non-healing ulcers are expensive to treat and heal. Approximately 2% of the United States’ general population suffers from non-healing wounds. Conservatively, the cost of treating these chronic wounds is estimated to exceed $50 billion per year. This is approximately ten times more than the annual budget of the World Health Organization. The prevalence of wound healing is similar to that of heart failure and cardiac diseases. However, unlike cardiac diseases little is known regarding the comparative treatments of wounds and their respective outcomes. Additionally, the field of monitoring and tracking wound care lacks the awareness compared with cardiac diseases.
Video-Analytics for Enhancing Safety and Decision-Support in Surgical Workflows
Authors: Kumar Suren , Sathianarayanan Madusudanan , Garimella Sudha , Singhal Pankaj , Corso Jason J. , Krovi Venkat
Published: February 2014

The present state-of-the-art surgical robotic systems though have a host of safety and failure systems still rely primarily on the surgeons-in-the-loop for safety amidst real-world uncertainties. Recent case studies involving surgical accidents and injuries have further increased the attention towards: (i) incorporating multiple levels of hard- and soft-safety and within their development stages, testing, validation and deployment; and (ii) objective based surgical skill assessment methodologies. We therefore would like to propose a feasible and effective method making use of the rich information content with automated-assists to make robotic surgeries smarter and safer. Specifically, in this paper we present our recent progress in video-based understanding to improve situational awareness, decision support and skill assessment aspects.
Investigation of the Effect of Stent Length and Stent Location on the Deformation Characteristics of the Femoropopliteal Artery After Knee Flexion: A Finite Element Study
Authors: Ní Ghriallais Ríona , Bruzzi Mark
Published: February 2014

There are a range of physiological movements such as knee and hip flexion that result in the deformation and loading of the femoropopliteal artery, characterised as axial compression, radial compression, bending and torsion [1]. The SFA is a prevalent location for peripheral arterial disease often requiring percutaneous transluminal angioplasty followed by stenting to restore vessel patency and uncompromised blood flow. Whilst stent placement provides the required scaffolding of the artery, opening up blockages and preventing elastic recoil of the vessel, it alters axial rigidity, changing the way in which the vessel deforms. With extreme stent rigidity and long stent lengths, severe bending can occur in the unstented vessel portions, proximal and distal to the stent. This has been observed in angiographic images of stented vessels that show unstented artery portions bending in an exaggerated manner adjacent to stented regions [2, 3]. It is postulated that due to knee flexion, deformation characteristics of the vessel are changed with extreme curvatures induced, initiating large stresses in the vessel tissue which may contribute to vascular injury, intimal hyperplasia and restenosis [2]. The goal of this work was to determine the effect of stent placement on deformation characteristics of the SFA after knee flexion using an anatomically accurate, three dimensional finite element model of the leg. Deformation characteristics (length change, curvature change and axial twist) that result from knee flexion movements of the stented vessel are quantified and linked with stress and strain levels within the artery for various cases of stent length and location within the femoropopliteal artery.
Numerical Correction of Error in a Computer-Aided Mechanical Navigation System for Arthroscopic Hip Surgery
Authors: Li Kristina Kangqiao , Geist Emily
Published: February 2014

Computer-Aided techniques have been deployed more commonly in recent years to assist with surgical procedures, particularly in the case of minimally invasive surgeries. Arthroscopy, as one of the most prevailing minimally invasive surgical procedures, increases surgical complexity due to the loss of joint visibility, but has many advantages. More obstacles are encountered during hip arthroscopy, given the tight socket-joint hip anatomy. Therefore, computer-aided techniques could be used to ease such difficulties during hip arthroscopy.
Non-Linear Viscoplastic Material Modeling of the Degradation Response of PLA
Authors: Bergstrom Jorgen S. , Quinn David J. , Chow Samual , Govindarajan Sekar M.
Published: February 2014

The bioabsorbable thermoplastic Poly(lactic acid), PLA, is extensively used in many medical applications including surgical sutures, drug delivery systems, internal fixation devices, tissue engineering scaffolds, and drug eluting stents. Frequently, a PLA component is required to withstand mechanical loading for a desired amount of time and then degrade via hydrolysis. In its raw, undegraded form, PLA exhibits a non-linear, viscoplastic mechanical response. Through the degradation process, the modulus, yield stress and flow behavior of PLA changes. Accurate simulations of bioabsorbable implants require a constitutive model that accounts for the viscoplastic nature of the material and its evolution over time. In this work we present the development of a new material model framework for predicting the time-dependent viscoplastic response of PLA. The proposed material model also captures the change in mechanical behavior over time due to hydrolysis. The details of the proposed model are presented, and the model predictions are compared to preliminary experimental data.
Annuloplasty Ring FEA Model Verification Using a Strain Gage
Authors: Ford Steven M. , Conklin Brian S. , Schmidt Paul A.
Published: February 2014

An annuloplasty ring is a medical device used to stabilize the perimeter of the orifice of a mitral or tricuspid valve in the human heart during reconstructive valve surgery. The annuloplasty ring under consideration consists of a metallic core surrounded by an elastomeric tube covered in cloth. Finite element analysis (FEA) has been performed to understand the stress distribution in the metallic ring core. The present study verifies the FEA model used for the ring core by comparing the surface strains predicted using FEA to those measured with a surface mounted strain gage during an analogous physical tensile test.
A Novel Method to Decrease Electric Field and SAR Using an External High Dielectric Sleeve at 3T Head MRI: Numerical and Experimental Results
Authors: Park Bu S. , Guag Joshua W. , Angelone Leonardo M. , Rajan Sunder S.
Published: February 2014

We present experimental and numerical simulation results showing that high dielectric materials (HDMs) located outside of a RF head coil decrease the electric field (E-field, |E|) with minimum change of the RF magnetic field (B1+) at 3T MRI imaging. Compared to previous research using HDMs located between the RF coil and sample, our method locating the HDM outside the coil allowed an increased sample size and more flexibility of HDM thickness optimization. Numerical simulation results showed more than 30% decrease in the local SAR at the boundary region of the head model. Validating experimental results showed a 21% decrease in the maximum |Etotal| using a HDM made of distilled water.
A Novel Micro-CT Based Anatomically Accurate Finite Element Model for Simulation-Aided Assessment of Mitral Valve Repairs
Authors: Lee Chung-Hao , Gorman Robert C. , Gorman Joseph H. , Aimini Rouzbeh , Sacks Michael S.
Published: February 2014

Many surgeons have come to view mitral valve (MV) repair as the treatment of choice in patients with mitral regurgitation (MR) [1]. According to recent long-term studies, the recurrence of significant MR after repair may be much higher than previously believed, particularly in patients with (ischemic mitral regurgitation) IMR [2]. We hypothesize that the restoration of homeostatic normal MV leaflet tissue stress in IMR repair techniques ultimately leads to improved repair durability. Therefore, the objective of this study is to develop a novel micro-anatomically accurate 3D finite element (FE) model that incorporates detailed collagen fiber architecture, accurate constitutive models, and micro-anatomically realistic valvular geometry to investigate the functional mitral valve and to aid in the assessment of the mitral valve repairs, especially the linking between the interstitial cellular deformations at the cellular level, the mechanobiological behaviors at the tissue level and the organ level mechanical responses as normal and repaired mitral valves maintaining their homeostatic state.
Comparative Study of Caucasian and Chinese Femur Shapes for Evidence-Based Implant Design
Authors: Vigneron Lara , Lawrenchuk Mike , Wivell Colleen , De Boodt Sebastian
Published: February 2014

With the increasing use of 3D medical imaging, it is possible to analyze 3D patient anatomy to extract features, trends and population specific shape information. This is applied to the development of ‘standard implants’ targeted to specific population groups.
Patient-Specific Computational Simulations of Transcatheter Aortic Valve Implantation (TAVI)
Authors: Bosi Giorgia M. , Capelli Claudio , Chung Robin , Mullen Michael , Taylor Andrew M. , Schievano Silvia
Published: February 2014

In the past decade, Transcatheter Aortic Valve Replacement (TAVI) has been shown to be a feasible, less invasive option to open heart surgery for aortic valve replacement; however, TAVI is indicated only in patients with severe, symptomatic, aortic stenosis and who are considered at high or prohibitive risk for conventional surgery [1]. To date, two different TAVI devices are available on the market — the balloon-expandable Edwards-Sapien® Valve (Edwards Lifesciences, CA, USA) and the self-expandable CoreValve ReValving System® (Medtronic, MN, USA) — with many other devices currently under development and clinical trials. The procedural success rate has been >90% in all studies [1], but vascular complications, electrical conduction abnormalities and paravalvular leak — 65–89% of cases, the majority being trivial to mild, with 0 to 26% moderate and 0 to 10% severe — still remain major safety concerns. In particular, a negative influence of moderate to severe paravalvular leak on survival rates has recently been demonstrated [2].
Use of QSAR Modeling to Predict the Carcinogenicity of Color Additives
Authors: Brown Ronald , White Shannon , Goode Jennifer , Pradeep Prachi , Merrill Stephen
Published: February 2014

Patients may be exposed to potentially carcinogenic color additives released from polymers used to manufacture medical devices; therefore, the need exists to adequately assess the safety of these compounds. The US FDA Center for Devices and Radiological Health (CDRH) recently issued draft guidance that, when final, will include FDA’s recommendations for the safety evaluation of color additives and other potentially toxic chemical entities that may be released from device materials. Specifically, the draft guidance outlines an approach that calls for evaluating the potential for the color additive to be released from the device in concert with available toxicity information about the additive to determine what types of toxicity information, if any, are necessary. However, when toxicity data are not available from the literature for the compounds of interest, a scientific rationale can sometimes be provided for omission of these tests. Although the FDA has issued draft guidance on this topic, the Agency continues to explore alternative approaches to understand when additional toxicity testing is needed to assure the safety of medical devices that contain color additives. An emerging approach that may be useful for determining the need for further testing of compounds released from device materials is Quantitative Structure Activity Relationship (QSAR) modeling. In this paper, we have shown how three publically available QSAR models (OpenTox/Lazar, Toxtree, and the OECD Toolbox) are able to successfully predict the carcinogenic potential of a set of color additives with a wide range of structures. As a result, this computational modeling approach may serve as a useful tool for determining the need to conduct carcinogenicity testing of color additives intended for use in medical devices.
Patient-Specific Simulations in Interventional Cardiology Practice: Early Results From a Clinical/Engineering Centre
Authors: Capelli Claudio , Bosi Giorgia M. , Cosentino Daria , Biglino Giovanni , Khambadkone Sachin , Derrick Graham , Bonhoeffer Philipp , Taylor Andrew M. , Schievano Silvia
Published: February 2014

Patient-specific models have been recently applied to investigate a wide range of cardiovascular problems including cardiac mechanics, hemodynamic conditions and structural interaction with devices [1]. The development of dedicated computational tools which combined the advances in the field of image elaboration, finite element (FE) and computational fluid-dynamic (CFD) analyses has greatly supported not only the understanding of human physiology and pathology, but also the improvement of specific interventions taking into account realistic conditions [2, 3]. However, the translation of these technologies into clinical applications is still a major challenge for the engineering modeling community, which has to compromise between numerical accuracy and response time in order to meet the clinical needs [4]. Hence, the validation of in silico against in vivo results is crucial. Finally, if the development of novel tools has recently attracted big investments [5], it has not been similarly easy to dedicate funds and time to test the developed technologies on large numbers of patient cases.
Misinterpretation of Stenosis Severity in the Presence of Serial Coronary Stenoses
Authors: D’Souza Gavin A. , Peelukhana Srikara V. , Banerjee Rupak K.
Published: February 2014

Diagnosis of the functional severity of an epicardial coronary stenosis using parameters like Fractional Flow Reserve, FFR (ratio of distal to proximal pressure of a stenotic region), might be affected in the presence of an additional downstream stenosis. In order to assess this effect, we have performed an in-vitro experiment which is used to validate a computational study. Three combinations of serial stenoses were tested: 80%-64%, 80%-80% and 80%-90% area stenosis (AS). The physiological mean hyperemic flow (flow at maximal arterial dilatation) values were obtained using an in-vitro experimental set-up. These flow rates were used as steady flow inputs by time-averaging the spatially averaged flow pulse over two cardiac cycles for the computational study. FFR values were calculated at hyperemic flow using both the experimental and numerical pressure data. As the downstream severity increased from 64% AS to 80% AS, hyperemic coronary flow decreased from 136.4 ml/min to 126.4 ml/min. Flow decreased further to 90.7 ml/min with a downstream severity of 90% AS. FFR of the intermediate stenosis increased from 0.76 to 0.79 and further to 0.88 as the downstream stenosis increased from 64% to 80% with a final severity of 90% AS. Similarly, numerically obtained FFR values increased to 0.83, 0.80 and 0.92 for the corresponding cases indicating an error within 7% of the experimental values. These results indicate that the presence of a downstream stenosis might lead to a clinical misinterpretation of the upstream stenosis severity.
Finite Element Implementation of a Planar Soft Tissue Structural Constitutive Model for Heart Valve Simulations
Authors: Fan Rong , Sacks Michael S.
Published: February 2014

Constitutive modeling is critical for numerical simulation and analysis of soft biological tissues. The highly nonlinear and anisotropic mechanical behaviors of soft tissues are typically due to the interaction of tissue microstructure. By incorporating information of fiber orientation and distribution at tissue microscopic scale, the structural model avoids ambiguities in material characterization. Moreover, structural models produce much more information than just simple stress-strain results, but can provide much insight into how soft tissues internally reorganize to external loads by adjusting their internal microstructure. It is only through simulation of an entire organ system can such information be derived and provide insight into physiological function. However, accurate implementation and rigorous validation of these models remains very limited. In the present study we implemented a structural constitutive model into a commercial finite element package for planar soft tissues. The structural model was applied to simulate strip biaxial test for native bovine pericardium, and a single pulmonary valve leaflet deformation. In addition to prediction of the mechanical response, we demonstrate how a structural model can provide deeper insights into fiber deformation fiber reorientation and fiber recruitment.
Finite Element Analysis of Magnesium Alloy Based Bone Fixation Devices
Authors: Pal Siladitya , Chaya Amy , Yoshizawa Sayuri , Chou Da-Tren , Hong Daeho , Maiti Spandan , Kumta Prashant N. , Sfeir Charles
Published: February 2014

Each year, there are over six million bone fractures in the U.S., over 30% of which require internal fixation devices to stabilize bone fragments during healing [1–2]. Currently, the gold standard materials for these devices are non-degradable titanium alloys. Unfortunately, these devices cause numerous complications and often require a secondary invasive removal surgery [3–4]. To circumvent these issues, resorbable polymeric devices have been developed, but their mechanical limitations render them inadequate for most load bearing applications [5–7].
Quantification of Experimental and Computational Uncertainties for Medical Devices Using Probabilistic Methods
Authors: Gupta Atul , Van der Velden Alex , Liu Xiangyi (Cheryl)
Published: February 2014

Uncertainties are inherent to physical testing of medical devices. They need to be accounted for in computational models in order to achieve proper degree of validation. These uncertainties may arise due to various factors like the applied boundary conditions, the behavior measurement and the geometry and material properties of a physical prototype. On the other hand, computational models have different types of uncertainties that are mostly related to modeling assumptions and refinement of the physical phenomena modeled as well as uncertainties with respect to the solver and numerical discretization.
AlGaN cladding-free 482 nm continuous wave nitride laser diodes grown by plasma-assisted molecular beam epitaxy
Authors: Skierbiszewski Czesław , Turski Henryk , Muziol Grzegorz , Wolny Paweł , Cywiński Grzegorz , Grzanka Szymon , Smalc-Koziorowska Julita , Sawicka Marta , Perlin Piotr , Wasilewski Zbig R. , Porowski Sylwester
Published: February 2014

The authors demonstrate continuous wave (CW) operating at 482 nm AlGaN-cladding-free laser diodes (LDs) grown by plasma assisted molecular beam epitaxy (PAMBE). The maximum CW output power was 220 mW. The PAMBE LD structures were grown on (0001) GaN substrates obtained by hydride vapor phase epitaxy, with threading dislocation density of 5 × 107 cm−2. The PAMBE process was carried out in metal-rich conditions supplying high nitrogen flux (ΦN) of 2 μm/h during quantum wells (QWs) growth. The authors found that high ΦN improves quality of high In content InGaN QWs. The role of nitrogen in growth of InGaN on wurtzite (0001) GaN surface as well as influence of LD design on threshold current density is discussed.
Cyclin A2 Induces Cardiac Regeneration After Myocardial Infarction Through Cytokinesis of Adult Cardiomyocytes
Authors: Shapiro Scott D. , Ranjan Amaresh K. , Kawase Yoshiaki , Cheng Richard K. , Kara Rina J. , Bhattacharya Romit , Guzman-Martinez Gabriela , Sanz Javier , Garcia Mario J. , Chaudhry Hina W.
Published: February 2014

Cyclin A2 mediates cardiac regeneration of infarcted porcine hearts.
Randomized, Controlled, Assessor-Blind Clinical Trial To Assess the Efficacy of Single- versus Repeated-Dose Albendazole To Treat Ascaris lumbricoides, Trichuris trichiura, and Hookworm Infection
Authors: Adegnika Ayola A. , Zinsou Jeannot F. , Issifou Saadou , Ateba-Ngoa Ulysse , Kassa Roland F. , Feugap Eliane N. , Honkpehedji Yabo J. , Dejon Agobe Jean-Claude , Kenguele Hilaire M. , Massinga-Loembe Marguerite , Agnandji Selidji T. , Mordmüller Benjamin , Ramharter Michael , Yazdanbakhsh Maria , Kremsner Peter G. , Lell Bertrand
Published: February 2014

In many regions where soil-transmitted helminth infections are endemic, single-dose albendazole is used in mass drug administration programs to control infections. There are little data on the efficacy of the standard single-dose administration compared to that of alternative regimens. We conducted a randomized, controlled, assessor-blinded clinical trial to determine the efficacies of standard and extended albendazole treatment against soil-transmitted helminth infection in Gabon. A total of 175 children were included. Adequate cure rates and egg reduction rates above 85% were found with a single dose of albendazole for
Ascaris
infection, 85% (95% confidence interval [CI], 73, 96) and 93.8% (CI, 87.6, 100), respectively, while two doses were necessary for hookworm infestation (92% [CI, 78, 100] and 92% [CI, 78, 100], respectively). However, while a 3-day regimen was not sufficient to cure
Trichuris
(cure rate, 83% [CI, 73, 93]), this regimen reduced the number of eggs up to 90.6% (CI, 83.1, 100). The rate ratios of two- and three-dose regimens compared to a single-dose treatment were 1.7 (CI, 1.1, 2.5) and 2.1 (CI, 1.5, 2.9) for
Trichuris
and 1.7 (CI, 1.0, 2.9) and 1.7 (CI, 1.0, 2.9) for hookworm. Albendazole was safe and well tolerated in all regimens. A single-dose albendazole treatment considerably reduces
Ascaris
infection but has only a moderate effect on hookworm and
Trichuris
infections. The single-dose option may still be the preferred regimen because it balances efficacy, safety, and compliance during mass drug administration, keeping in mind that asymptomatic low-level helminth carriage may also have beneficial effects. (This study has been registered at ClinicalTrials.gov under registration number NCT01192802.)