bluuebunny/crossref_metadata_2025 huggingface dataset:
A neural network approach for improving airfoil active flutter suppression under control-input constraints
Authors: Tang Difan , Chen Lei , Tian Zhao F , Hu Eric
Published: May 2020

This study deals with improving airfoil active flutter suppression under control-input constraints from the optimal control perspective by proposing a novel optimal neural-network control. The proposed approach uses a modified value function approximation dynamically tuned by an extended Kalman filter to solve the Hamilton–Jacobi–Bellman equality online for continuously improved optimal control to address optimality in parameter-varying nonlinear systems. Control-input constraints are integrated into the controller synthesis by introducing a generalized nonquadratic cost function for control inputs. The feasibility of using a performance index involving the nonquadratic control-input cost with the modified value function approximation is examined through the Lyapunov stability analysis. Wind tunnel experiments were conducted for controller validation, where an optimal controller synthesized offline via linear parameter-varying technique was used as a benchmark and compared. It is shown, both theoretically and experimentally, that the proposed method can effectively improve airfoil active flutter suppression under control-input constraints.
Childhood Maltreatment and Psychosis: A Comparative Validity Study of Maltreatment Indices
Authors: Beasley Rhianna E. , Kivisto Aaron J. , Leonhardt Bethany L. , Waldron Jordan S.
Published: May 2020

Childhood maltreatment is a robust risk factor for psychosis, but it remains unclear whether different measurement methods provide equivalent validity in predicting psychotic symptoms. This study compared the predictive validity of two common indices of maltreatment at age 12—children’s self-report and Child Protective Services (CPS) reports—on the development of psychotic symptoms at age 18 using data from a large, multisite longitudinal study ( N = 629). Consistent with prior research, agreement was low between indices, with the prevalence of self-reported maltreatment being 2–3 times higher. A quarter of the sample endorsed at least one psychotic symptom at age 18, most commonly delusions. While CPS-indicated maltreatment was generally not associated with later psychotic symptoms, all forms of self-reported maltreatment were. Sexual abuse demonstrated a particularly strong relationship with psychosis, especially hallucinations. These results suggest that self-reports may provide stronger predictive validity than CPS indications of maltreatment in the assessment of psychosis risk, indicating that a child’s interpretation of trauma matters more than the traumatic event itself in this regard.
Energy harvesting from a nanopiezoelectric/piezomagnetic sandwich beam with porous properties
Authors: Fan Tao
Published: May 2020

Piezoelectric/piezomagnetic energy harvester has attracted great interest, which can convert magnetic energy into electric power. However, the challenges are how to provide lasting electric energy to the nanoscale components and avoid the inherent brittleness of the piezoelectric and piezomagnetic materials. Therefore, a nanoporous piezoelectric/piezomagnetic beam with a storage circuit is proposed to be an energy harvester in this paper. The nanoporous beam is treated as a sandwich composite beam with the piezoelectric/piezomagentic core bulks and the surface or interface layers. Based on the surface effect theory and the Boit’s porous elasticity, the governing equations and the analytical solutions of the nanoporous piezoelectric/piezomagnetic energy harvester with the flexural mode are obtained. The numerical calculation points out that the resonant frequency, output power density and the output voltage depend on the surface materials parameters, porosity properties, solid-fluid coupling effects, the geometrical dimensions, as well as the piezoelectric/piezomagnetic materials composition of the structure. The results reveal that the resonant frequency interval can be controlled and the output electric power can be improved by adjusting the materials and geometrical parameters.
Supply–Demand of Water Resource of a Basin With High Anthropic Pressure: Case Study Quenane-Quenanito Basin in Colombia
Authors: Vargas-Pineda Oscar I , Trujillo-González Juan M , Torres-Mora Marco A
Published: May 2020

Water scarcity has increased in the last century due to the effects of climate change and the over-exploitation of anthropic activities that deteriorate strategic ecosystems in watersheds. This study quantified the water consumption of anthropic activities according to the water footprint (WF) and the water supply available (WSA) using the GR2M hydrological simulation model in the Quenane-Quenanito basin in Colombia. The objective of this study was to analyze the dynamic supply–demand of water and identify potential conflicts associated with the use of water. The results of this study show that the WF of the basin was 17.01 million m3/year, 79.97% of which was the green WF and 20.03% of which was the blue WF, and that the WSA of the basin was 272.1 million m3/year. In addition, potential conflicts over the use of water were identified due to water scarcity in 11 sub-basins during the months of January to March. In conclusion, analyzing the demand and supply of water in basins and taking into account their spatiotemporal distribution allows us to measure the impacts of anthropic activities on water resources, which can prevent potential conflicts associated with the use of water between sectors or the involvement of ecological dynamics.
What’s gender got to do with populism?
Authors: Donà Alessia
Published: May 2020

While populism has accumulated an extensive research, its gender dimension has remained largely understudied. Only recently has a literature emerged that focuses on the gender dimension of radical right populist parties in Europe, where they have risen from marginal to government positions. In this article, I provide a guide to the topics and results of this recent development and delineate future research lines. In doing so, I will illustrate the relevance of adopting a gender perspective in studying the phenomenon of populism.
Static and dynamic performance characteristics of powder lubricated symmetrical three-lobed bearing
Authors: Jose Jijo , Behera Niranjana
Published: May 2020

Hydrodynamic oil bearings applied at elevated temperatures and extreme operating conditions are subjected to the problem of oil degradation. In order to overcome such conditions, dry powder lubricants are used as lubricants in the hydrodynamic journal bearings. Thus the problem of thermal degradation of oil at high temperatures can be eliminated. In this work, the static and dynamic characteristics of a symmetric three-lobed bearing lubricated with powdered particles have been predicted. Influence of the ellipticity ratio on the performance of the three-lobed bearing has also been investigated. It is observed that an increase in the ellipticity ratio increases the coefficient of friction and stability, but decreases the side leakage and the load carrying capacity of the three-lobed bearing. Also, it was observed that the large-sized powdered particles induce better load carrying capacity and better stability than the small-sized particles.
Evolution mechanism of subsurface defect structure in particle micro-cutting iron–carbon alloy process
Authors: Li Jun-ye , Xie Hong-cai , Meng Wen-qing , Zhang Xin-ming , Zhao Wei-hong , Shi Guang-feng
Published: May 2020

In order to explore the evolution mechanism of subsurface defect structure of iron–carbon alloy workpiece during abrasive flow machining, the molecular dynamics model of SiC particle micro-cutting iron–carbon alloys was established. The Common Neighbor Analysis and Dislocation Extraction Algorithm were applied to identify the crystal structure and lattice defects. The distribution and evolution of defect structure during micro-cutting were analyzed and discussed, and the removal mechanism of workpiece material during micro-cutting was revealed. The results show that dislocations, stacking faults, V-shaped dislocation loops, atomic clusters, and point defect structures were generated in the subsurface layer of the iron–carbon alloy workpiece during micro-cutting. Under the action of extrusion and friction of SiC particles, some atoms in the shear slip zone were largely displaced. The plastic deformation occurred on the workpiece and formed chips and machining surfaces. Some atoms extended into the interior of the workpiece material, resulting in subsurface defect structure. After the completion of particle micro-cutting, some defect structures of the subsurface layer disappeared, and some defect structures remained in the subsurface of the workpiece in a certain form, forming a subsurface defect layer.
Correlation between surface roughness parameters and contact stress of gear
Authors: Duo Yang , Jinyuan Tang , Wei Zhou , Yuqin Wen
Published: May 2020

To reveal the relationship between rough tooth surface microstructure characteristics and contact performance, contact analysis is carried out based on the measured surface topography of the tooth surface of ultrasonic grinding by utilizing the elastic-plastic contact mechanics and statistical correlation analysis theory. Simple correlation analysis and partial correlation analysis are adopted for the gear three-dimensional surface roughness parameters and the maximum Mises stress and maximum shear stress. Then, the method of stepwise regression analysis and path analysis is used to construct the best fitting linear model of 3D roughness parameters and the maximum Mises stress and maximum shear stress, and the parameters’ decision coefficient is obtained. The research shows: (1) the rank of comprehensive influence factors of the maximum Mises stress is as follows: arithmetical mean height ( Sa), peak material portion ( Smr1), maximum peak height ( Sp), reduced peak height ( Spk), and minimum curvature radius and height ratio ( K), where Smr1, Spk, and K are negatively correlated with the maximum Mises stress; (2) the comprehensive influence variables of the maximum shear stress are in the order of Sa, Spk, and Vmp, among which Spk and Vmp are inversely related to the maximum shear stress.
Acceptability of telehealth-delivered rehabilitation: Experiences and perspectives of people with traumatic brain injury and their carers
Authors: Rietdijk Rachael , Power Emma , Attard Michelle , Togher Leanne
Published: May 2020

Introduction

Communication skills training for people with traumatic brain injury (TBI) and their carers is recommended best practice. Delivery via telehealth could improve access to this training. This paper focuses on the acceptability of telehealth delivery of communication skills training.

Methods

A mixed-methods investigation of acceptability of telehealth to people with TBI and their carers was incorporated into a clinical trial. Thirty-six people with TBI (23 metropolitan and 13 regional) and their carers were recruited. Metropolitan participants were randomly allocated to telehealth or in-person intervention at a 1:3 ratio. Regional participants were allocated to telehealth. Telehealth and in-person participants were compared on retention, time to complete the programme, home practice completion and therapeutic alliance ratings. Participants completed semi-structured interviews regarding their views on telehealth, which were analysed using thematic analysis.

Results

There were no significant differences between telehealth and in-person participants in retention rate, time to complete the programme, degree of home practice completion or therapeutic alliance ratings. Three themes were identified: ‘telehealth delivery opens a window for access to rehabilitation in the context of my daily life’, ‘in-person delivery offers rehabilitation based on natural human interaction’ and ‘weighing telehealth against in-person delivery’.

Discussion

Participants found telehealth delivery acceptable, as indicated by the similarity between groups in the quantitative process measures, and as reported in interviews. Some reported a preference for in-person delivery if there had been a choice of delivery mode. Participants described characteristics of the two delivery modes which were relevant to their attitudes towards telehealth.
Principals’ strategies for increasing students’ participation in school leadership in a rural, mountainous region in Pakistan
Authors: Afzal Tajik Mir , Wali Abdul
Published: May 2020

This study aimed to explore the principal’s perceptions about, and strategies for, increasing students’ active participation in the day-to-day affairs and decision-making at a secondary school located in a rural, mountainous region of Pakistan. By exploring the principal’s leadership practices, this study aims to answer the question, ‘how can school principals promote students’ participation in school leadership and, in turn, how can such participation ultimately lead to a socially just and democratic community?’ To us ‘school leadership’ is not a set of skills or positional authority that lies in one individual – the principal – but it is a practice which is widely distributed and engaged by a range of people including students in the day-to-day affairs and business of the school. Although, students’ participation in curricular and co-curricular activities and decision-making processes in schools is widely studied elsewhere, there is hardly any study on this topic in the context of Pakistan, particularly with reference to rural schools. Therefore, an empirical investigation based on a qualitative case study method was conducted to collect data from the principal as well as from other members of the school community regarding the leadership practices that promote students’ active participation in school affairs. The findings of the study reveal a number of interesting and contextually relevant strategies used by the principal as well as the gaps between his beliefs and practices and the challenges he faces in increasing students’ participation in various activities and decisions at the school.
Gaps in social security protection of mobile persons: Options for filling these gaps
Authors: Essers Ger , Pennings Frans
Published: May 2020

The effects of crossing borders can be advantageous or disadvantageous for the persons concerned; these are all part of the game and cannot be challenged on the basis of EU law. After all, the Treaty on the Functioning of the European Union (TFEU) does not provide powers for harmonisation, but only for coordination. However, the coordination rules themselves may make a person worse off when he or she makes use of the right to free movement. More precisely, such an effect may occur in combination with differences between national systems to which coordination rules are applied. One example is that the coordination rules provide that a person is subject to unemployment benefits in the country of residence and, as a result, if that person becomes ill, also to sickness benefit in that country. If the duration of sickness benefit in the country of residence is 52 weeks, but the waiting period for disability benefit (supposing, for instance, that this is (mainly) due from the country of employment) is 104 weeks, there is a gap of 52 weeks in protection. The relevance of such gaps is not to solve particular cases as such; after all, these are closely linked to particular national systems. The relevance lies in the more general approach that is now being developed by the Court of Justice to address such gaps. This will be useful in cases other than those discussed here and may be further developed in order to be codified in the Coordination Regulation.
Brexit and the reform of social security coordination: The UK’s metamorphosis from rule maker to rule taker
Authors: Roberts Simon
Published: May 2020

This article examines the United Kingdom’s negotiating position on the revision of the EU Coordinating Regulations proposed by the European Commission in December 2016, in the context of Brexit and the negotiations on the Withdrawal Agreement. The Withdrawal Agreement contains provisions on the future coordination of social security for UK and EU nationals who have exercised their freedom of movement rights before the end of the transition period. The coordination envisaged by the Withdrawal Agreement has not been sealed at the point of the UK’s departure but will continue to evolve and incorporate future changes in the EU Coordinating Regulations, including the reforms contained in the Commission’s current legislative proposal. The UK had a seat at the negotiating table until it left the European Union on 31 January 2020, which it used to try to influence the reform of the Coordinating Regulations to reflect its future interests. The article finds that, while the UK participated in negotiating the current revision of the Coordinating Regulations and several of the revisions are in line with its aims, its influence is waning as the UK moves from being a rule maker to a rule taker in Europe.
Symbolic vibration: A meaning-based framework for the study of vibrator consumption
Authors: Mayr Cornelia
Published: May 2020

This article explores the creation process and the subsequent meaning development of vibrators within a framework consisting of various theories of material culture. The conceptual scheme is based on the view that four underlying junctures of meaning creation and vibrator consumption, namely (1) vibrators as a medical implement, (2) vibrators as a household appliance, (3) vibrators as a liberating political object and (4) vibrators as a post-feminist ‘toy’, interact to (re)produce and change the meaning of this sexually imbued product. First, existing research is reviewed on the history and consumption of vibrators, and findings are synthesized concerning product functions. Theories of material culture and product meaning are then incorporated as a means to gain ontological and epistemological insights into the nature of this sexual product. Finally, a framework is presented that builds on these foundational theories, including a discussion of its benefits for the sociology of consumption. The article concludes that the meaning of vibrators can be seen as being intricately bound up with processes of social movements, individual interpretation and identity politics as well as with historical, economic and cultural phenomena.
Sarcasm detection using machine learning algorithms in Twitter: A systematic review
Authors: Sarsam Samer Muthana , Al-Samarraie Hosam , Alzahrani Ahmed Ibrahim , Wright Bianca
Published: May 2020

Recognizing both literal and figurative meanings is crucial to understanding users’ opinions on various topics or events in social media. Detecting the sarcastic posts on social media has received much attention recently, particularly because sarcastic comments in the form of tweets often include positive words that represent negative or undesirable characteristics. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement was used to understand the application of different machine learning algorithms for sarcasm detection in Twitter. Extensive database searching led to the inclusion of 31 studies classified into two groups: Adapted Machine Learning Algorithms (AMLA) and Customized Machine Learning Algorithms (CMLA). The review results revealed that Support Vector Machine (SVM) was the best and the most commonly used AMLA for sarcasm detection in Twitter. In addition, combining Convolutional Neural Network (CNN) and SVM was found to offer a high prediction accuracy. Moreover, our result showed that using lexical, pragmatic, frequency, and part-of-speech tagging can contribute to the performance of SVM, whereas both lexical and personal features can enhance the performance of CNN-SVM. This work also addressed the main challenges faced by prior scholars when predicting sarcastic tweets. Such knowledge can be useful for future researchers or machine learning developers to consider the major issues of classifying sarcastic posts in social media.
Influence of a Multidisciplinary Program of Diet, Exercise, and Mindfulness on the Quality of Life of Stage IIA-IIB Breast Cancer Survivors
Authors: Ruiz-Vozmediano Julia , Löhnchen Sarah , Jurado Lucas , Recio Rosario , Rodríguez-Carrillo Andrea , López Miriam , Mustieles Vicente , Expósito Manuela , Arroyo-Morales Manuel , Fernández Mariana F.
Published: May 2020

Background: Integrative oncology has proven to be a useful approach to control cancer symptoms and improve the quality of life (QoL) and overall health of patients, delivering integrated patient care at both physical and emotional levels. The objective of this randomized trial was to evaluate the effects of a triple intervention program on the QoL and lifestyle of women with breast cancer. Methods: Seventy-five survivors of stage IIA-IIB breast cancer were randomized into 2 groups. The intervention group (IG) received a 6-month dietary, exercise, and mindfulness program that was not offered to the control group (CG). Data were gathered at baseline and at 6 months postintervention on QoL and adherence to Mediterranean diet using clinical markers and validated questionnaires. Between-group differences at baseline and 3 months postintervention were analyzed using Student’s t test for related samples and the Wilcoxon and Mann-Whitney U tests. Results: At 6 months postintervention, the IG showed significant improvements versus CG in physical functioning ( p = .027), role functioning ( p = .028), and Mediterranean diet adherence ( p = .02) and a significant reduction in body mass index ( p = .04) and weight ( p = .05), with a mean weight loss of 0.7 kg versus a gain of 0.55 kg by the CG ( p = .05). Dyspnea symptoms were also increased in the CG versus IG ( p = .066). Conclusions: These results demonstrate that an integrative dietary, physical activity, and mindfulness program enhances the QoL and healthy lifestyle of stage IIA-IIB breast cancer survivors. Cancer symptoms may be better managed by the implementation of multimodal rather than isolated interventions.
Predictive analytics framework for accurate estimation of child mortality rates for Internet of Things enabled smart healthcare systems
Authors: Islam Muhammad , Usman Muhammad , Mahmood Azhar , Abbasi Aaqif Afzaal , Song Oh-Young
Published: May 2020

Globally, under-five child mortality is a substantial health problem. In developing countries, reducing child mortality and improving child health are the key priorities in health sectors. Despite the significant reduction in deaths of under-five children globally, developing countries are still struggling to maintain an acceptable mortality rate. Globally, the death rate of under-five children is 41 per 1000 live births. However, the death rate of children in developing nations like Pakistan and Ethiopia per 1000 live births is 74 and 54, respectively. Such nations find it very challenging to decrease the mortality rate. Data analytics on healthcare data plays a pivotal role in identifying the trends and highlighting the key factors behind the children deaths. Similarly, predictive analytics with the help of Internet of Things based frameworks significantly advances the smart healthcare systems to forecast death trends for timely intervention. Moreover, it helps in capturing hidden associations between health-related variables and key death factors among children. In this study, a predictive analytics framework has been developed to predict the death rates with high accuracy and to find the significant determinants that cause high child mortality. Our framework uses an automated method of information gain to rank the information-rich mortality variables for accurate predictions. Ethiopian Demographic Health Survey and Pakistan Demographic Health Survey data sets have been used for the validation of our proposed framework. These real-world data sets have been tested using machine learning classifiers, such as Naïve Bayes, decision tree, rule induction, random forest, and multi-layer perceptron, for the prediction task. It has been revealed through our experimentation that Naïve Bayes classifier predicts the child mortality rate with the highest average accuracy of 96.4% and decision tree helps in identifying key classification rules covering the factors behind children deaths.
Preparation of polypyrrole coated on Polyester Cleanroom Wiper as heater device
Authors: Xie Juan , Pan Wei , Chen Yan , Guo Zheng
Published: May 2020

Recently, many efforts have been dedicated to achieve lightweight, stretchable, and flexible heat device. Here, the Polyester Cleanroom Wiper coated with poly(pyrrole) as flexible material showing electrothermal properties are reported. Poly(pyrrole) particles are synthesized on the cloth via a simple in situ polymerization method with different Py/FeCl3 concentration ratios. A highly conductive cloth with surface resistance of 23 Ω/sq can be produced by changing the Py/FeCl3 concentration. The flexible composites showed sensitive electrothermal performance, and a steady-state temperature of 89.1°C could be reached at 6 V. In addition, temperature, voltage, and time-dependent temperature results showed that the heating performance was strongly dependent on the resistance and external voltage. Herein, as-prepared composites were further analyzed as ultra-fast responding electrothermal heaters, indicating their great potential in application value as wearable electronic textiles.
Evaluation of anchorage performance of the switchboard cabinet under seismic loading condition
Authors: Lee Sang-Moon , Jung Woo-Young
Published: May 2020

In this study, the seismic response of the anchorage used for switchboard cabinets at a power plant was presented based on the results of an experiment and numerical simulations. In the experimental study, shaking table tests were performed to investigate the overall structural behavior of switchboard cabinets. The finite element modeling was conducted using the ABAQUS program, and in order to validate the proposed finite element model, the natural frequency, stress, and displacement were compared with the experimental results. A slight difference was found in the results due to the problem cup-like deformation at the anchorage of the bottom, but it showed reasonable agreement when considering the results for all behaviors. Using the proven model, nonlinear dynamic analysis was performed using three types of a period waves. The maximum stress on the anchorage occurred when a long-period wave was applied, and the horizontal maximum displacement of the cabinet was approximately 10 times greater than when an ultra-short-period wave was applied. It is expected that the flexibility of the cabinet stiffness resulted in more structural weakness, especially under a long-period wave, and that is recommended to focus on displacement rather than stress when establishing seismic design guidelines for switchboard cabinets.
Assessment of the knowledge and perception of generic medications among pharmacy and medical students in the University of Sharjah, United Arab Emirates
Authors: Sharif Suleiman I , Aldayeh Souad , Alsomali Huda , Hayat Fatmah
Published: May 2020

Background

Generic substitution has become a common practice in several countries, primarily because of a major cost-minimizing strategy without compromising healthcare quality.

Objective

The study was carried out to assess the knowledge and perception of generic medication among final year pharmacy and medical students in the University of Sharjah.

Method

A cross-sectional survey was designed, pre-validated, and distributed during the period of September to November 2019 in the University of Sharjah, United Arab Emirates. The study research covered various aspects on knowledge and perception of generic medicines. It was distributed to 180 final year pharmacy and medicine students. Data were analyzed using SPSS, and Chi square test was used to determine the level of significance at p < 0.05.

Result

A total of 171 of 180 questionnaires were returned back including 87 and 84 surveys from pharmacy and medical students respectively producing a response rate of 95%. The majority of respondents in both collages were females, Arabs, and with parents of non-health care professions. Significantly more pharmacy than medical students agreed that cost-effective therapy and generics were covered in their study courses, generics are bioequivalent to brands and must contain the same amount of active ingredients like brands, that they are confident of their knowledge and more easily recall drugs by their generic names. Again more pharmacy students agreed that pharmacists should have the right to perform substitution but disagreed to the statement that generics takes longer time to produce therapeutic effects than brands.

Conclusion

Overall, Final-year students of pharmacy had better level of knowledge and perception of generic medicines and their right to perform generic substitution. Medical students seem to have limited knowledge of certain important aspects. Therefore, improvement of educational courses of future health-care professionals should be implemented early to enhance students’ awareness toward generic substitution.
Ethical rationale for better coordination of clinical research on COVID-19
Authors: Bompart Francois
Published: May 2020

Hundreds of clinical trials of potential treatments and vaccines for the “coronavirus 19 disease” (COVID-19) have been set up in record time. This is a remarkable reaction to the global pandemic, but the absence of a global coordination of clinical research efforts raises serious ethical concerns. Some COVID-19 patients might carry the burden of clinical trial involvement even though their trial cannot be completed as researchers are competing for patients. A shortage of medicines can occur when existing drugs are diverted for clinical trials. Research ethics committees are overburdened with multiple applications. A multitude of trials can also overstretch medical staff and risk neglecting non-COVID-19 patients. And finally, conflicting conclusions from a multitude of heterogeneous trials might lead to delays in public health decisions about life-saving issues. These challenges are made worse by the unpredictable evolution of epidemics, the active involvement of political decision-makers in scientific issues and the pressure of social media globally. While freedom to conduct research must be safeguarded, global health emergency situations would greatly benefit from effective international coordination mechanisms for clinical research.
Novel morphological multi-scale evaluation system for quality assessment of decellularized liver scaffolds
Authors: Moulisová Vladimíra , Jiřík Miroslav , Schindler Claudia , Červenková Lenka , Pálek Richard , Rosendorf Jáchym , Arlt Janine , Bolek Lukáš , Šůsová Simona , Nietzsche Sandor , Liška Václav , Dahmen Uta
Published: May 2020

Decellularized scaffolds can serve as an excellent three-dimensional environment for cell repopulation. They maintain tissue-specific microarchitecture of extracellular matrix proteins with important spatial cues for cell adhesion, migration, growth, and differentiation. However, criteria for quality assessment of the three-dimensional structure of decellularized scaffolds are rather fragmented, usually study-specific, and mostly semi-quantitative. Thus, we aimed to develop a robust structural assessment system for decellularized porcine liver scaffolds. Five scaffolds of different quality were used to establish the new evaluation system. We combined conventional semi-quantitative scoring criteria with a quantitative scaffold evaluation based on automated image analysis. For the quantitation, we developed a specific open source software tool (ScaffAn) applying algorithms designed for texture analysis, segmentation, and skeletonization. ScaffAn calculates selected parameters characterizing structural features of porcine liver scaffolds such as the sinusoidal network. After evaluating individual scaffolds, the total scores predicted scaffold interaction with cells in terms of cell adhesion. Higher scores corresponded to higher numbers of cells attached to the scaffolds. Moreover, our analysis revealed that the conventional system could not identify fine differences between good quality scaffolds while the additional use of ScaffAn allowed discrimination. This led us to the conclusion that only using the combined score resulted in the best discrimination between different quality scaffolds. Overall, our newly defined evaluation system has the potential to select the liver scaffolds most suitable for recellularization, and can represent a step toward better success in liver tissue engineering.
Medications for the treatment of obesity in adolescents
Authors: Woodard Kaylee , Louque Logan , Hsia Daniel S.
Published: May 2020

While there are eight medications/combinations approved for the treatment of obesity in adults, the options for the treatment of obesity in adolescents remain limited. Evidence for obesity medication use in adolescents is limited due to the relatively small number of clinical trials that have been completed and the few adolescents that have been included in many of the trials. The goal of this review will be to present the current evidence for the medications approved for adolescents, medications not approved for adolescents but have adolescent data, and medications approved for adults with the prospect for use in adolescents. We will also discuss current limitations and next steps in the exploration of future treatment options.
Demonstration of reciprocal diurnal variation in human serum T3 and rT3 concentration demonstrated by mass spectrometric analysis and establishment of thyroid hormone reference intervals
Authors: Sun Qian , Avallone Lívia , Stolze Brian , Araque Katherine A. , Özarda Yesim , Jonklaas Jacqueline , Parikh Toral , Welsh Kerry , Masika Likhona , Soldin Steven J.
Published: May 2020

Background:

There has been a wide range of reference intervals proposed in previous literature for thyroid hormones due to large between-assay variability of immunoassays, as well as lack of correction for collection time. We provided the diurnal reference intervals for five thyroid hormones, namely total thyroxine (TT4), total triiodothyronine (TT3), free thyroxine (FT4), free triiodothyronine (FT3), and reverse T3 (rT3), measured in serum samples of healthy participants using a liquid chromatography/tandem mass spectrometry (LC-MS/MS) method.

Methods:

Couplet serum samples (a.m. and p.m.) were collected from 110 healthy females and 49 healthy males. Healthy volunteers were recruited from four participating centers between 2016 and 2018. Measurements of thyroid hormones were obtained by LC-MS/MS analysis.

Results:

Our study revealed significant uptrend in AM to PM FT4 ( p < 0.0001) samples, downtrend in AM to PM TT3 ( p = 0.0004) and FT3 samples ( p < 0.0001), and AM to PM uptrend in rT3 samples ( p < 0.0001). No difference was observed for TT4 between AM and PM. No significant sex differences were seen for any of the five thyroid hormones.

Conclusion:

When diagnosing thyroid disorders, it is important to have accurate measurement of thyroid hormones, and to acknowledge the diurnal fluctuation found, especially for FT3. Our study highlights the importance of standardization of collection times and implementation of LC-MS/MS in thyroid hormone measurement.
Rectal duplication in an adult cat: a novel transanal surgical approach
Authors: Carbonell Buj Elena , Billet Jean-Philippe , Vanel Maïa , Caron Alexandre
Published: May 2020

Case summary

A 3-year and 8-month-old male entire European domestic shorthair cat was presented with a history of recurrent rectal prolapse, straining and pain when defaecating. Previous non-surgical and surgical treatments had not provided a satisfactory result. Rectal prolapse had recurred within 2 weeks of treatment. Upon clinical examination, an intraluminal mass could be palpated rectally. A CT scan examination revealed the mass was of a cystic nature and the cyst was surgically excised via a transanal approach. On histological evaluation, the cyst walls consisted of three of the layers of normal rectum: mucosa, muscularis of the mucosa and submucosa. These findings led to the definite diagnosis of rectal duplication.

Relevance and novel information

Enteric duplication is among the differential diagnoses for straining and rectal prolapse in cats. This condition has previously been discussed in the veterinary literature, with a single case report describing a rectal duplication in a cat. In that particular case, the authors described a perineal surgical approach. Here we present a novel approach whereby the duplicated material was excised transanally in order to limit intra- and postoperative morbidity. The clinical outcome was excellent in our case, with complete resolution of clinical signs and no recurrence 18 months after surgery.
Exon skipping of TGFβRI affects signalling and ECM expression in hypertrophic scar-derived fibroblasts
Authors: Raktoe Rajiv S , Rietveld Marion H , Out-Luiting Jacoba J , Kruithof-de Julio Marianna , van Zuijlen Paul PM , van Doorn Remco , Ghalbzouri Abdoelwaheb El
Published: May 2020

Background:

In burn patients, wound healing is often accompanied by hypertrophic scar (HS) development, resulting in both functional and aesthetic problems. HSs are characterised by abundant presence of myofibroblasts that contribute to overproduction of extracellular matrix (ECM) that is regulated by the TGF-β signalling pathway. Studies have shown that inhibition of TGF-β receptors in fibrotic diseases reduces the fibrotic load. In the present study, we aim to inactivate ALK5, also known as TGF-β receptor I, in human HS fibroblasts by exon skipping using antisense oligonucleotides (AONs).

Methods:

HS biopsies were used to isolate and set up fibroblast monocultures. AONs targeting ALK5 were supplemented to the fibroblast cultures to induce exon skipping, while pharmacological ALK5 inhibition was induced using SB431542. AON delivery in HS fibroblasts was examined using immunofluorescence (IF), while TGF-β signalling downstream targets, such as Smad2/3, PAI-1, ACTA2, COL1A1 and COL3A1, were analysed using touchdown polymerase chain reaction (PCR), quantitative PCR (qPCR), IF or western blotting.

Results:

Our data clearly demonstrate that AONs were successfully delivered in the nuclei of HS fibroblasts and that functional exon skipping of ALK5 took place as confirmed with touchdown PCR and qPCR. In addition, exon skipping affected the expression of ECM-related genes, such as type I/III collagens, PAI-1 and CCN2. Moreover, AON treatment did not affect the migration of HS fibroblasts in a model for wound healing.

Conclusion:

Exon skipping is a promising tool to modulate the TGF-β signalling pathway in HS. This would open a therapeutic window for the treatment of patients suffering from HSs.
Latent Trait, Latent-Trait State, and a Network Approach to Mental Problems and Their Mechanisms of Change
Authors: Hoffart Asle , Johnson Sverre Urnes
Published: May 2020

In this theoretical study, we examined whether and how a latent trait, a latent-trait state, and a network conceptualization of mental problems account for their descriptive features and causal mechanisms. The latent-trait approach is restricted to between-persons relations and thus provides no direct tests of mechanisms, which involve within-persons relations. The latent-trait-state approach can address within-persons relations, but the assumption of independence between latent constructs is often violated. Moreover, the focus on latent states results only in global clinical recommendations. In the network approach, clinical disorders are viewed as causal networks of observable mental problems and symptoms. The network approach has so far not addressed the episodic clusters of reactions surrounding every symptom. We propose an extended network approach, which identifies mechanistic relationships with the causal interactions among the reactions of these clusters. This approach is associated with differentiated clinical models and leads to specific clinical recommendations.
Minimally Invasive Anterior Longitudinal Ligament Release for Anterior Column Realignment
Authors: Godzik Jakub , Pereira Bernardo de Andrada , Hemphill Courtney , Walker Corey T. , Wewel Joshua T. , Turner Jay D. , Uribe Juan S.
Published: May 2020

Study Design:

Review of the literature.

Objectives:

Anterior column realignment (ACR) is a powerful but relatively new minimally invasive technique for deformity correction. The purpose of this study is to provide a literature review of the ACR surgical technique, reported outcomes, and future directions.

Methods:

A review of the literature was performed regarding the ACR technique. A review of patients at our single center who underwent ACR was performed, with illustrative cases selected to demonstrate basic and nuanced aspects of the technique.

Results:

Clinical and cadaveric studies report increases in segmental lordosis in the lumbar spine by 73%, approximately 10° to 33°, depending on the degree of posterior osteotomy and lordosis of the hyperlordosis interbody spacer. These corrections have been found to be associated with a similar risk profile compared with traditional surgical options, including a 30% to 43% risk of proximal junctional kyphosis in early studies.

Conclusions:

ACR represents a powerful technique in the minimally invasive spinal surgeon’s toolbox for treatment of complex adult spinal deformity. The technique is capable of significant sagittal plane correction; however, future research is necessary to ascertain the safety profile and long-term durability of ACR.
Defining the MIS-TLIF: A Systematic Review of Techniques and Technologies Used by Surgeons Worldwide
Authors: Lener Sara , Wipplinger Christoph , Hernandez R. Nick , Hussain Ibrahim , Kirnaz Sertac , Navarro-Ramirez Rodrigo , Schmidt Franziska Anna , Kim Eliana , Härtl Roger
Published: May 2020

Study Design:

Systematic review.

Objective:

To date there is no consensus among surgeons as to what defines an MIS-TLIF (transforaminal lumbar interbody fusion using minimally invasive spine surgery) compared to an open or mini-open TLIF. This systematic review aimed to examine the MIS-TLIF techniques reported in the recent body of literature to help provide a definition of what constitutes the MIS-TLIF, based on the consensus of the majority of surgeons.

Methods:

We created a database of articles published about MIS-TLIF between 2010 and 2018. We evaluated the technical components of the MIS-TLIF including instruments and incisions used as well the order in which key steps are performed.

Results:

We could identify several patterns for MIS-TLIF performance that seemed agreed upon by the majority of MIS surgeons: use of paramedian incisions; use of a tubular retractor to perform a total facetectomy, decompression, and interbody cage implantation; and percutaneous insertion of the pedicle-screw rod constructs with intraoperative imaging.

Conclusion:

Based on this review of the literature, the key features used by surgeons performing MIS TLIF include the use of nonexpandable or expandable tubular retractors, a paramedian or lateral incision, and the use of a microscope or endoscope for visualization. Approaches using expandable nontubular retractors, those that require extensive subperiosteal dissection from the midline laterally, or specular-based retractors with wide pedicle to pedicle exposure are far less likely to be promoted as an MIS-based approach. A definition is necessary to improve the communication among spine surgeons in research as well as patient education.
The Role of Minimal Access Surgery in the Treatment of Spinal Metastatic Tumors
Authors: Barzilai Ori , Bilsky Mark H. , Laufer Ilya
Published: May 2020

Study Design:

Literature review.

Objective:

To provide an overview of the recent advances in minimal access surgery (MAS) for spinal metastases.

Methods:

Literature review.

Results:

Experience gained from MAS in the trauma, degenerative and deformity settings has paved the road for MAS techniques for spinal cancer. Current MAS techniques for the treatment of spinal metastases include percutaneous instrumentation, mini-open approaches for decompression and tumor resection with or without tubular/expandable retractors and thoracoscopy/endoscopy. Cancer care requires a multidisciplinary effort and adherence to treatment algorithms facilitates decision making, ultimately improving patient outcomes. Specific algorithms exist to help guide decisions for MAS for extradural spinal metastases. One major paradigm shift has been the implementation of percutaneous stabilization for treatment of neoplastic spinal instability. Percutaneous stabilization can be enhanced with cement augmentation for increased durability and pain palliation. Unlike osteoporotic fractures, kyphoplasty and vertebroplasty are known to be effective therapies for symptomatic pathologic compression fractures as supported by high level evidence. The integration of systemic body radiation therapy for spinal metastases has eliminated the need for aggressive tumor resection allowing implementation of MAS epidural tumor decompression via tubular or expandable retractors and preliminary data exist regarding laser interstitial thermal therapy and radiofrequency ablation for tumor control. Neuronavigation and robotic systems offer increased precision, facilitating the role of MAS for spinal metastases.

Conclusions:

MAS has a significant role in the treatment of spinal metastases. This review highlights the current utilization of minimally invasive surgical strategies for treatment of spinal metastases.
Cervical Arthroplasty: Long-Term Outcomes of FDA IDE Trials
Authors: Parish Jonathan M. , Coric Domagoj
Published: May 2020

Study Design:

Special Issues MIS/Navigation.

Objectives:

Over the past decade, cervical total disc replacement has been established in numerous randomized clinical trials as an alternative to anterior cervical discectomy and fusion. The purpose of this review is to evaluate the long-term outcomes after cervical arthroplasty.

Methods/Results:

Early outcomes (studies with 2-year follow-up) after arthroplasty established the efficacy of total disc replacement and, more recently, long-term studies have shown the durability of these good clinical outcomes. Biomechanical and clinical data have demonstrated that this motion preservation technology decreases adjacent-level stresses compared with fusion. Additionally, long-term outcomes as well as outcomes after multilevel arthroplasty have now established the role of arthroplasty in select patient populations, namely patients with 1- and 2-level spondylosis/stenosis causing radiculopathy from C3-7.

Conclusions:

Data on adjacent segment deterioration and adjacent segment reoperation remains controversial but suggest a positive effect after arthroplasty. But these are multifactorial issues and we still do not fully understand all the factors affecting adjacent segment pathology and longer-term studies after arthroplasty will continue to address this issue.
Platypnea Orthodeoxia Syndrome Secondary to Intracardiac Shunt Following Orthotopic Liver Transplantation
Authors: Larson Sophia R. , Vutien Philip , Steinberg Zachary L.
Published: May 2020

Platypnea orthodeoxia syndrome (POS) occurs when an upright position results in acute-onset hypoxemia and is relieved with recumbency. POS can be due to intracardiac shunting, intrapulmonary shunting, ventilation-perfusion mismatch, or a combination of these. We report a case of POS that developed 3 days post liver transplantation as a result of new-onset right to left shunting across a patent foramen ovale. Right heart catheterization revealed a posteriorly directed inferior vena cava likely due to altered inferior vena cava—right atrial junction anatomy as a result of liver transplantation. The patient underwent successful transcatheter patent foramen ovale closure with a 25-mm Gore Cardioform septal occluder device with immediate and sustained improvement in hypoxia.