Search results for: Tristan Snell

Authors: Kazeem Adesina Dauda, Waheed Babatunde Yahya

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To design a tree that maximizes within-node homogeneity, there is a need for a homogeneity measure that is appropriate for event history data with multiple risks. We consider the use of Deviance and Modified Cox-Snell residuals as a measure of impurity in Classification Regression Tree (CART) and compare our results with the results of Fiona (2008) in which homogeneity measures were based on Martingale Residual. Data structure approach was used to validate the performance of our proposed techniques via simulation and real life data. The results of univariate competing risk revealed that: using Deviance and Cox-Snell residuals as a response in within node homogeneity classification tree perform better than using other residuals irrespective of performance techniques. Bone marrow transplant data and double-blinded randomized clinical trial, conducted in other to compare two treatments for patients with prostate cancer were used to demonstrate the efficiency of our proposed method vis-à-vis the existing ones. Results from empirical studies of the bone marrow transplant data showed that the proposed model with Cox-Snell residual (Deviance=16.6498) performs better than both the Martingale residual (deviance=160.3592) and Deviance residual (Deviance=556.8822) in both event of interest and competing risks. Additionally, results from prostate cancer also reveal the performance of proposed model over the existing one in both causes, interestingly, Cox-Snell residual (MSE=0.01783563) outfit both the Martingale residual (MSE=0.1853148) and Deviance residual (MSE=0.8043366). Moreover, these results validate those obtained from the Monte-Carlo studies.

Keywords: within-node homogeneity, Martingale residual, modified Cox-Snell residual, classification and regression tree

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Authors: Alam Anshary, Flora Pasaru, Shahabuddin

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The Cocoa Pod Borer (CPB), Conopomorpha cramerella (Snell.) is present on most of the larger cocoa producing islands in Indonesia. Various control measures CPB has been carried out by the farmers, but the results have not been effective. This study aims to determine the effect of application of Beauveria bassiana treatments and pruning technique to the control of CPB in the cocoa plantation people. Research using completely randomized design with 4 treatments and 3 replications, treatment consists of B.bassiana, Pruning, B. bassiana+pruning (Bb + Pr), as well as the control. The results showed that the percentage of PBK attack on cocoa pods in treatment (Bb + Pr) 3.50% the lowest compared to other treatments. CPB attack percentage in treatment B.bassiana 6.15%; pruning 8.75%, and 15.20% control. Results of the analysis of production estimates, the known treatments (Bb + Pr) have the highest production (1.95 tonnes / ha). The model results estimated production is Y= 0,20999 + 0,53968X1 + 0,34298X2+ 0,31410X3 + 0,35629X4 + 0,08345X5 + 0,29732X6. Farm production costs consist of fixed costs and variable costs, fixed costs are costs incurred by the farmer that the size does not affect the results, such as taxes and depreciation of production equipment. Variable costs are costs incurred by farmers who used up in one year cocoa farming activities. The cost of production in farming cocoa without integrated techniques control of CPB is Rp. 9.205.550 million/ha, while the cost of production with integrated techniques control is Rp. 6.666.050 million/ha.

Keywords: cacao, cocoa pod borer, pruning, Beauveria bassiana, production costs

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Authors: Jade Fersterer, Tristan Snell, Mark Rickinson

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This paper is designed to provide a review of the literature concerning the impact of natural environments on student learning and wellbeing in Australia. Specific areas of interest include how child-led and teacher-led pedagogies differ in outdoor learning settings, and the impact of each approach on children’s well-being, behavior, relationships with others as well as educational outcomes. The review will include links to possibilities for future research, including a Ph.D. currently being undertaken in Australia, which aims to fulfill a considerable gap in psychological, educational and outdoor learning research, regarding how natural environments are being used by teachers to improve learning and wellbeing among primary school students. The proposed study aims to understand if children’s experience of learning, 1. in a natural environment, and 2. in a child-led way, can support and strengthen their skills across several areas of development, including those required for positive educational outcomes. Data will be collected from a sample of primary school students and teachers via both quantitative and qualitative methods, including a pre- and post-questionnaire, direct observation, and semi-structured interviews. The study will have valuable implications for the provision of quality education as well as the promotion of good health and wellbeing. The implications of the research will be useful not only for teachers and parents but also for Psychologists working with children and young people in both a school and clinical setting. Understanding the impacts and implications of child-led learning and exposure to natural environments provides the opportunity to build on the current school curriculum. The inclusion of child-led experiences in nature may provide a simple way to build enthusiasm for school and learning, cultivating skills for life and relationships as well as meeting current curriculum requirements and building capacity for ongoing academic pursuits. In addition, understanding the impact of learning in a natural environment on wellbeing will assist in the development and dissemination of an educational model that could help mitigate the negative health outcomes associated with reduced physical activity and decreasing contact with nature among children.

Keywords: child-led learning, educational outcomes, natural environments, wellbeing

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Authors: Ian McCulloh, Andrew Placona, Darren Stewart, Daniel Gause, Kevin Kiernan, Morgan Stuart, Christopher Zinner, Laura Cartwright

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An estimated 22-25% of viable deceased donor kidneys are discarded every year in the US, while waitlisted candidates are dying every day. As many as 85% of transplanted organs are refused at least once for a patient that scored higher on the match list. There are hundreds of clinical variables involved in making a clinical transplant decision and there is rarely an ideal match. Decision makers exhibit an optimism bias where they may refuse an organ offer assuming a better match is imminent. We propose a semi-parametric Cox proportional hazard model, augmented by an accelerated failure time model based on patient specific suitable organ supply and demand to estimate a time-to-next-offer. Performance is assessed with Cox-Snell residuals and decision curve analysis, demonstrating improved decision support for up to a 5-year outlook. Providing clinical decision makers with quantitative evidence of likely patient outcomes (e.g., time to next offer and the mortality associated with waiting) may improve decisions and reduce optimism bias, thus reducing discarded organs and matching more patients on the waitlist.

Keywords: decision science, KDPI, optimism bias, organ transplant

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Authors: Abdelkader Basli, Jean-Claude Delaunay, Eric Pedrot, Jean-Michel Mérillon, Jean-Pierre Monti, Khodir Madani, Mohamed Chibane, Tristan Richard

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The antioxidant and antimicrobial activities of Origanum glandulosum collected in Algeria have been studied. Extract was prepared from aerial part of endemic Algerian oregano. The produced extract has been characterized in terms of total phenols (using Folin method), total flavonoid, antioxidant activities (using the DPPH radical scavenging method and ORAC assay) and microbial activity against four bacteria: Streptococcus aureus, Bacillus subtilis, Escherichia coli, Klebsiella pneumoniae one yeast: Candida albicans and one fungi: Aspergillus niger. The results pointed the antioxidant activities of the extract of O. glandulosum and antimicrobial activities against all bacteria and C. Candida, but no effect on A. niger. High performance liquid chromatography combined with mass spectrometry (LC-MS) and nuclear magnetic resonance (LC-NMR) were used to separate and identify the major compounds present in the oregano extract. Rosmarinic acid, globoidnan A and B, lithospermic acid B and three flavonoids were identified.

Keywords: origanum glandulosum, antioxidant, microbial activity, polyphenol, LC-MS, LC-NMR

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Authors: Abraham J. Rizkalla, Tristan D. Yan

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Atrial myxoma is the most common primary cardiac tumor, and can result in cardiac failure secondary to obstruction, or systemic embolism due to fragmentation. Traditionally, excision of atrial an myxoma has been performed through median sternotomy, however the robotic approach offers several advantages including less pain, improved cosmesis, and faster recovery. Here, we highlight the less well recognized advantages and technical aspects to robotic myxoma resection. This video-presentation demonstrates the resection of a papillary subtype left atrial myxoma using the DaVinci© Xi surgical robot. The 10x magnification and 3D vision allows for the interface between the tumor and the interatrial septum to be accurately dissected, without the need to patch the interatrial septum. Several techniques to avoid tumor fragmentation and embolization are demonstrated throughout the procedure. The tumor was completely excised with clear margins. There was no atrial septal defect or mitral valve injury on post operative transesophageal echocardiography. The patient was discharged home on the fourth post-operative day. This video-presentation highlights the advantages of the robotic approach in atrial myxoma resection compared with sternotomy, as well as emphasizing several technical considerations to avoid potential complications.

Keywords: cardiac surgery, left atrial myxoma, cardiac tumour, robotic resection

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Authors: Cam Minh Tri Tien, Richard Fenrich, Tristan Shelley, Nam Mai-Duy, Allan Malano, Xuesen Zeng

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Since additive manufacturing is a layer-by-layer deposition approach, good bonding quality between adjacent layers is critically important to achieve optimal mechanical performance, including applications in pressure vessels. The need to enhance the strength of printed products, especially in the build direction where layup gaps and voids exist between the printed layers, has garnered significant attention. The proposed research will focus on improving the current Fused Deposition Modelling (FDM) process to produce polymers reinforced with chopped fibers, utilizing a controlled heat zone to enhance the adhesion between printed layers. Energy will be applied to both printed and printing layers to improve the bonding strength between adjacent layers. Through the enhanced FDM process, the mechanical performance of composite parts will experience a substantial improvement, particularly in the build direction, as compared to current FDM methods. A combination of experimental, numerical, and analytical methods will be employed to demonstrate the enhanced performance of heat-controlled 3D printed parts.

Keywords: 3D Printing, pressure vessels, interlayer bonding, controlled heat

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Authors: Omotayo Olalere

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The relevance of code-switching for intercultural communication through literary translation cannot be overemphasized. The translation of code-switching and its implications for translations studies have been studied in the context of African literature. In these cases, code-switching was examined in the more general terms of its usage in source text and not particularly in Ngugi’s novels and its translations. In addition, the functions of translation and code-switching in the lyrics of some popular African songs have been studied, but this study is related more with oral performance than with written literature. As such, little has been done on the German translation of code-switching in African works. This study intends to fill this lacuna by examining the concept of code-switching in the German translations in Ngugi’s Petals of Blood. The aim is to highlight the significance of code-switching as a phenomenon in this African (Ngugi’s) novel written in English and to also focus on its representation in the two German translations. The target texts to be used are Verbrannte Blueten and Land der flammenden Blueten. “Abrogration“ as a concept will play an important role in the analysis of the data. Findings will show that the ideology of a translator plays a huge role in representing the concept of “abrogration” in the translation of code-switching in the selected source text. The study will contribute to knowledge in translation studies by bringing to limelight the need to foreground aspects of language contact in translation theory and practice, particularly in the African context. Relevant translation theories adopted for the study include Bandia’s (2008) postcolonial theory of translation and Snell-Hornby”s (1988) cultural translation theory.

Keywords: code switching, german translation, ngugi wa thiong’o, petals of blood

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Authors: Christian Klettner, Ian Eames, Tristan Robinson

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Tsunami is characterised by their very long time periods and can have devastating consequences when these inundate through built-up coastal regions as in the 2004 Indian Ocean and 2011 Tohoku Tsunami. This work aims to investigate the effect of these long waves on the flow through and around a group of buildings, which are abstracted to circular cylinders. The research approach used in this study was using experiments and numerical simulations. Large-scale experiments were carried out at HR Wallingford. The novelty of these experiments is (I) the number of bodies present (up to 64), (II) the long wavelength of the input waves (80 seconds) and (III) the width of the tank (4m) which gives the unique opportunity to investigate three length scales, namely the diameter of the building, the diameter of the array and the width of the tank. To complement the experiments, dam break flow past the same arrays is investigated using three-dimensional numerical simulations in OpenFOAM. Dam break flow was chosen as it is often used as a surrogate for the tsunami in previous research and is used here as there are well defined initial conditions and high quality previous experimental data for the case of a single cylinder is available. The focus of this work is to better understand the effect of the solid void fraction on the force and flow through and around the array. New qualitative and quantitative diagnostics are developed and tested to analyse the complex coupled interaction between the cylinders.

Keywords: computational fluid dynamics, tsunami, forces, complex geometry

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Authors: Charles Klein O. Gorit, Mark Tristan J. Quimque Jr., M. Cecilia V. Almeda, Concepcion M. Salvana

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Chitosan is a promising biopolymer commonly found in crustacean shells that has plausible effects in water purification and wastewater treatment. It is a primary derivative of chitin and considered second of the most abundant biopolymer prior to cellulose. Morphological analysis had been done using Scanning Electron Microscopy with Energy Dispersive Microscopy (SEM/EDS), and due to its porous nature, it showcases a certain degree of porosity, hence, larger adsorption site of heavy metal. The Energy Dispersive Spectroscopy of the chitosan and ‘lead-bound’ chitosan, shows a relative increase of percent abundance of lead cation from 1.44% to 2.08% hence, adsorption occurs. Chitosan, as a nitrogenous polysaccharide, subjected to Fourier transform infrared spectroscopy (FTIR) analysis shows amide bands ranging from 1635.36 cm⁻¹ for amide 1 band and 1558.40 cm-1 for amide 2 band with NH stretching. For ‘lead-bound’ chitosan, the FT-IR analysis shows a change in peaks upon adsorption of Pb(II) cation. The spectrum shows broadening of OH and NH stretching band. Such observation can be attributed to the probability that the attachment of Pb(II) ions is in these functional groups. A column filter was devised with lead-bound chitosan to determine the zero point charge (pHzpc) of the biopolymer. The results show that at pH 8.34, below than the zpc level of literatures cited for lead which ranges from pH 4 to 7, favors the adsorption site of chitosan and its capability to adsorb traces amount of aqueous lead.

Keywords: chitosan, biopolymer, FT-IR, SEM, zero-point charge, heavy metal, lead ions

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Authors: Kanika Naresh Singh, Uday Shankar

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Background: Human behaviours are influenced by drives. Sexual drive is one of them. Education regarding sexual behaviour plays a great role in shaping one’s attitude towards it. These days after attaining the age of puberty, adolescents are confused and feel shy to talk about it. In order to get information, they refer to various types of sources and these sources play a greater role in spreading awareness in the mass adolescent population. Sometimes it also leads to the building of myths and misconceptions. Due to increasing incidences of HIV/AIDS, RTIs/STIs and teenage pregnancies, there is a rising need to impart sex education. Aim: The aim of this research was to study the level of sexual awareness among the youth of Bihar and also study their sexual behaviour and sources of influence. It also aims to study the correlation between sexual awareness, behaviour and sources of sexual knowledge among youth in Bihar. Methods: The sample size for the project was 50 youth consisting of both boys and girls, in between the age group of 18 to 23 years from urban and semi-urban areas. The purposive sampling method was used in the research. The tools used were the Sexual Awareness Questionnaire and Sexual Behavior and Sources of Influence (SBSI) scale. The sexual Awareness Questionnaire was developed by Snell, having 35 items. A socio-demographic data sheet was also used. Results: The youth had poor sexual awareness. Internet and Friends were found to be the major source for gathering information. The youth of Bihar were less inclined towards resolving their doubts with their parents. There was a positive correlation between sexual awareness, behaviour and sources of knowledge. Conclusion: The youth of Bihar has poor sexual knowledge. Internet and Friends are major sources of information. Sex Education should be promoted as suggested by various institutions like World Health Organization United Nations. Psychiatrists and psychologists have a key leadership role in introducing these potentially emotionally challenging issues to the youth with consideration of psychosocial and cultural factors.

Keywords: sexual awareness, sexual behavior, sources of influence, youths, Bihar, India

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Authors: Abraham J. Rizkalla, Tristan D. Yan

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Purpose: Durable mitral valve repair is preferred to a replacement, avoiding the need for anticoagulation or re-intervention, with a reduced risk of endocarditis. Robotic mitral repair has been gaining favour globally as a safe, effective, and reproducible method of minimally invasive valve repair. In this work, we showcase the use of the Davinci© Xi robotic platform to perform several advanced techniques, working synergistically to achieve successful mitral repair in advanced mitral disease. Techniques: We present the case of a Barlow type mitral valve disease with a tall and redundant posterior leaflet resulting in severe mitral regurgitation and systolic anterior motion. Firstly, quadrangular resection of P2 is performed to remove the excess and redundant leaflet. Secondly, a sliding leaflet plasty of P1 and P3 is used to reconstruct the posterior leaflet. To anchor the newly formed posterior leaflet to the papillary muscle, CV-4 Goretex neochordae are fashioned using the innovative string, ruler, and bulldog technique. Finally, mitral valve annuloplasty and closure of a patent foramen ovale complete the repair. Results: There was no significant residual mitral regurgitation and complete resolution of the systolic anterior motion of the mitral valve on post operative transoesophageal echocardiography. Conclusion: This work highlights the robotic approach to complex repair techniques for advanced mitral valve disease. Familiarity with resection and sliding plasty, neochord implantation, and annuloplasty allows the modern cardiac surgeon to achieve a minimally-invasive and durable mitral valve repair when faced with complex mitral valve pathology.

Keywords: robotic mitral valve repair, Barlow's valve, sliding plasty, neochord, annuloplasty, quadrangular resection

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Authors: Djebbar Atmani, Dina Kilani, Tristan Richard

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Medicinal plants are an important source for the discovery of potential new substances for use in medicine and food. Pistacia lentiscus, Fraxinus angustifolia and Clematis flammula, plants growing in the Mediterranean basin, are widely used in traditional medicine. Therefore, the present study was designed to investigate their antioxidant, anti-inflammatory, antidiabetic, anti-mutagenic/genotoxic and neuroprotective potential and identification of active compounds using appropriate methodology. Plant extracts and fractions exhibited high scavenging capacity against known radicals, enhanced superoxide dismutase and catalase activitiesand restored blood glucose levels, in vivo, to normal values, in agreement with the in vitro enzymatic inhibition data, through inhibition of amylase and glucosidase activities. Administration of Pistacia lentiscus extracts significantly decreased carrageenan-induced mice paw oedema and reduced effectively IL-1β levels in cell culture, whereas Fraxinus angustifolia extracts showed good healing capacity against wounds when applied topically on rabbits. Pistacia lentiscus and Fraxinus angustifolia extracts showed good neuro-protection and restored cognitive functions in mice, while Clematis flammula extracts showed potent anti-ulcerogenic activity associated to a promising anti-mutagenic/genotoxic activity. HPLC-MS and NMR analyses allowed the identification and structural elucidation of several known and new anthocyanins, flavonols and flavanols. Therefore, Pistacia lentiscus, Fraxinus angustifolia and Clematis flammulacould be used in palliative treatments against inflammatory conditions and diabetes complications, as well as against deterioration of cognitive functions.

Keywords: pistacia lentiscus, clematis flammula, fraxinus angustifolia, phenolic compounds, biological activity

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Authors: David Taillis, Oussama Becissa, Julien Gabaston, Jean-Michel Merillon, Tristan Richard, Stephanie Cluzet

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Nowadays, there is a strong pressure to reduce the phytosanitary inputs of synthetic chemistry in vineyards. It is, therefore, necessary to find viable alternatives in order to protect the vine against its major diseases. For this purpose, we suggest the use of a plant extract enriched in antimicrobial compounds. Being produced from vine trunks and roots, which are co-products of wine production, the extract produced is part of a circular economy. The antimicrobial molecules present in this plant material are polyphenols and, more particularly, stilbenes, which are derived from a common base, the resveratrol unit, and that are well known vine phytoalexins. The stilbenoids were extracted from trunks and roots (30/70, w/w) by a double extraction with ethyl acetate followed by enrichment by liquid-liquid extraction. The produced extract was characterized by UHPLC-MS, then its antimicrobial activities were tested on Plasmopara viticola and Botrytis cinerea in the laboratory and/or in greenhouse and in vineyard. The major compounds were purified, and their antimicrobial activity was evaluated on B. cinerea. Moreover, after its spraying, the effect of the stilbene extract on the plant defence status was evaluated by analysis of defence gene expression. UHPLC-MS analysis revealed that the extract contains 50% stilbenes with resveratrol, ε-viniferin and r-viniferin as major compounds. The extract showed antimicrobial activities on P. viticola with IC₅₀ and IC₁₀₀ respectively of 90 and 300 mg/L in the laboratory. In addition, it inhibited 40% of downy mildew development in greenhouse. However, probably because of the sensitivity of stilbenes to the environment, such as UV degradation, no activity has been observed in vineyard towards P. viticola development. For B. cinerea, the extract IC50 was 123 mg/L, with resveratrol and ε-viniferin being the most active stilbenes (IC₅₀ of 88 and 142 mg/L, respectively). The analysis of the expression of defence genes revealed that the extract can induce the expression of some defence genes 24, 48, and 72 hours after treatment, meaning that the extract has a defence-stimulating effect at least for the first three days after treatment. In conclusion, we produced a plant extract enriched in stilbenes with antimicrobial properties against two major grapevine pathogenic agents P. viticola and B. cinerea. In addition, we showed that this extract displayed eliciting activity of plant defences. This extract can therefore represent, after formulation development, a viable eco-friendly alternative for vineyard protection. Subsequently, the effect of the stilbenoid extract on primary metabolism will be evaluated by quantitative NMR.

Keywords: antimicrobial, bioprotection, grapevine, Plasmopara viticola, stilbene

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Authors: Elaine Lima Da Fonseca, Eliomar Pereira Da Silva Filho

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The modeling of areas susceptible to soil loss by hydro erosive processes consists of a simplified instrument of reality with the purpose of predicting future behaviors from the observation and interaction of a set of geoenvironmental factors. The models of potential areas for soil loss will be obtained through binary logistic regression, artificial neural networks, and support vector machines. The choice of the municipality of Colorado do Oeste in the south of the western Amazon is due to soil degradation due to anthropogenic activities, such as agriculture, road construction, overgrazing, deforestation, and environmental and socioeconomic configurations. Initially, a soil erosion inventory map constructed through various field investigations will be designed, including the use of remotely piloted aircraft, orbital imagery, and the PLANAFLORO/RO database. 100 sampling units with the presence of erosion will be selected based on the assumptions indicated in the literature, and, to complement the dichotomous analysis, 100 units with no erosion will be randomly designated. The next step will be the selection of the predictive parameters that exert, jointly, directly, or indirectly, some influence on the mechanism of occurrence of soil erosion events. The chosen predictors are altitude, declivity, aspect or orientation of the slope, curvature of the slope, composite topographic index, flow power index, lineament density, normalized difference vegetation index, drainage density, lithology, soil type, erosivity, and ground surface temperature. After evaluating the relative contribution of each predictor variable, the erosion susceptibility model will be applied to the municipality of Colorado do Oeste - Rondônia through the SPSS Statistic 26 software. Evaluation of the model will occur through the determination of the values of the R² of Cox & Snell and the R² of Nagelkerke, Hosmer and Lemeshow Test, Log Likelihood Value, and Wald Test, in addition to analysis of the Confounding Matrix, ROC Curve and Accumulated Gain according to the model specification. The validation of the synthesis map resulting from both models of the potential risk of soil erosion will occur by means of Kappa indices, accuracy, and sensitivity, as well as by field verification of the classes of susceptibility to erosion using drone photogrammetry. Thus, it is expected to obtain the mapping of the following classes of susceptibility to erosion very low, low, moderate, very high, and high, which may constitute a screening tool to identify areas where more detailed investigations need to be carried out, applying more efficient social resources.

Keywords: modeling, susceptibility to erosion, artificial intelligence, Amazon

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Authors: Nicholas McNamara, John Brookes, Michael Williams, Manish Mathew, Elizabeth Brookes, Tristan Yan, Paul Bannon

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Objective: Pericardial effusions are an uncommon but potentially fatal complication after cardiac surgery. The goal of this study was to describe the incidence and risk factors associated with the development of pericardial effusion requiring drainage after coronary artery bypass graft surgery (CABG). Methods: A retrospective analysis was undertaken using prospectively collected data. All adult patients who underwent CABG at our institution between 1st January 2017 and 31st December 2018 were included. Pericardial effusion was diagnosed using transthoracic echocardiography (TTE) performed for clinical suspicion of pre-tamponade or tamponade. Drainage was undertaken if considered clinically necessary and performed via a sub-xiphoid incision, pericardiocentesis, or via re-sternotomy at the discretion of the treating surgeon. Patient demographics, operative characteristics, anticoagulant exposure, and postoperative outcomes were examined to identify those variables associated with the development of pericardial effusion requiring drainage. Tests of association were performed using the Fischer exact test for dichotomous variables and the Student t-test for continuous variables. Logistic regression models were used to determine univariate predictors of pericardial effusion requiring drainage. Results: Between January 1st, 2017, and December 31st, 2018, a total of 408 patients underwent CABG at our institution, and eight (1.9%) required drainage of pericardial effusion. There was no difference in age, gender, or the proportion of patients on preoperative therapeutic heparin between the study and control groups. Univariate analysis identified preoperative atrial arrhythmia (37.5% vs 8.8%, p = 0.03), reduced left ventricular ejection fraction (47% vs 56%, p = 0.04), longer cardiopulmonary bypass (130 vs 84 min, p < 0.01) and cross-clamp (107 vs 62 min, p < 0.01) times, higher drain output in the first four postoperative hours (420 vs 213 mL, p <0.01), postoperative atrial fibrillation (100% vs 32%, p < 0.01), and pleural effusion requiring drainage (87.5% vs 12.5%, p < 0.01) to be associated with development of pericardial effusion requiring drainage. Conclusion: In this study, the incidence of pericardial effusion requiring drainage was 1.9%. Several factors, mainly related to preoperative or postoperative arrhythmia, length of surgery, and pleural effusion requiring drainage, were identified to be associated with developing clinically significant pericardial effusions. High clinical suspicion and low threshold for transthoracic echo are pertinent to ensure this potentially lethal condition is not missed.

Keywords: coronary artery bypass, pericardial effusion, pericardiocentesis, tamponade, sub-xiphoid drainage

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Authors: Tristan R. Fraser, Christopher D. Steadman, Christopher J. Boos

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Myopericarditis is an inflammation syndrome characterised by clinical diagnostic criteria for pericarditis, such as chest pain, combined with evidence of myocardial involvement, such as elevation of biomarkers of myocardial damage, e.g., troponins. It can rarely be a complication of therapeutics used for dysregulated immune-mediated diseases such as inflammatory bowel disease (IBD), for example, mesalazine. The infrequency of mesalazine-induced myopericarditis adds to the challenge in its recognition. Rapid diagnosis and the early introduction of treatment are crucial. This case report follows a 24-year-old professional footballer with a past medical history of ulcerative colitis, recently started on mesalazine for disease control. Three weeks after mesalazine was initiated, he was admitted with fever, shortness of breath, and chest pain worse whilst supine and on deep inspiration, as well as elevated venous blood cardiac troponin T level (cTnT, 288ng/L; normal: <13ng/L). Myocarditis was confirmed on initial inpatient cardiac MRI, revealing the presence of florid myocarditis with preserved left ventricular systolic function and an ejection fraction of 67%. This was a longitudinal case study following the progress of a single individual with myopericarditis over four acute hospital admissions over nine weeks, with admissions ranging from two to five days. Parameters examined included clinical signs and symptoms, serum troponin, transthoracic echocardiogram, and cardiac MRI. Serial measurements of cardiac function, including cardiac MRI and transthoracic echocardiogram, showed progressive deterioration of cardiac function whilst mesalazine was continued. Prior to cessation of mesalazine, transthoracic echocardiography revealed a small global pericardial effusion of < 1cm and worsening left ventricular systolic function with an ejection fraction of 45%. After recognition of mesalazine as a potential cause and consequent cessation of the drug, symptoms resolved, with cardiac MRI performed as an outpatient showing resolution of myocardial oedema. The patient plans to make a return to competitive sport. Patients suffering from myopericarditis are advised to refrain from competitive sport for at least six months in order to reduce the risk of cardiac remodelling and sudden cardiac death. Additional considerations must be taken in individuals for whom competitive sport is an essential component of their livelihood, such as professional athletes. Myopericarditis is an uncommon, however potentially serious medical condition with a wide variety of aetiologies, including viral, autoimmune, and drug-related causes. Management is mainly supportive and relies on prompt recognition and removal of the aetiological process. Mesalazine-induced myopericarditis is a rare condition; as such increasing awareness of mesalazine as a precipitant of myopericarditis is vital for optimising the management of these patients.

Keywords: myopericarditis, mesalazine, inflammatory bowel disease, professional athlete

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Authors: Maxwell Henderson, Tristan Cook, Justin Chan Jin Le, Mark Hodson, YoungJung Chang, John Novak, Daniel Padilha, Nishan Kulatilaka, Ansu Bagchi, Sanjoy Ray, John Kelly

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We present a method of using adiabatic quantum optimization (AQO) to solve a mixed integer nonlinear programming (MINLP) problem instance. The MINLP problem is a general form of a set of NP-hard optimization problems that are critical to many business applications. It requires optimizing a set of discrete and continuous variables with nonlinear and potentially nonconvex constraints. Obtaining an exact, optimal solution for MINLP problem instances of non-trivial size using classical computation methods is currently intractable. Current leading algorithms leverage heuristic and divide-and-conquer methods to determine approximate solutions. Creating more accurate and efficient algorithms is an active area of research. Quantum computing (QC) has several theoretical benefits compared to classical computing, through which QC algorithms could obtain MINLP solutions that are superior to current algorithms. AQO is a particular form of QC that could offer more near-term benefits compared to other forms of QC, as hardware development is in a more mature state and devices are currently commercially available from D-Wave Systems Inc. It is also designed for optimization problems: it uses an effect called quantum tunneling to explore all lowest points of an energy landscape where classical approaches could become stuck in local minima. Our work used a novel algorithm formulated for AQO to solve a special type of MINLP problem. The research focused on determining: 1) if the problem is possible to solve using AQO, 2) if it can be solved by current hardware, 3) what the currently achievable performance is, 4) what the performance will be on projected future hardware, and 5) when AQO is likely to provide a benefit over classical computing methods. Two different methods, integer range and 1-hot encoding, were investigated for transforming the MINLP problem instance constraints into a mathematical structure that can be embedded directly onto the current D-Wave architecture. For testing and validation a D-Wave 2X device was used, as well as QxBranch’s QxLib software library, which includes a QC simulator based on simulated annealing. Our results indicate that it is mathematically possible to formulate the MINLP problem for AQO, but that currently available hardware is unable to solve problems of useful size. Classical general-purpose simulated annealing is currently able to solve larger problem sizes, but does not scale well and such methods would likely be outperformed in the future by improved AQO hardware with higher qubit connectivity and lower temperatures. If larger AQO devices are able to show improvements that trend in this direction, commercially viable solutions to the MINLP for particular applications could be implemented on hardware projected to be available in 5-10 years. Continued investigation into optimal AQO hardware architectures and novel methods for embedding MINLP problem constraints on to those architectures is needed to realize those commercial benefits.

Keywords: adiabatic quantum optimization, mixed integer nonlinear programming, quantum computing, NP-hard

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