Multiple irregularities and thrombus in a patient with COVID-19 presenting with ST-segment elevation myocardial infarction: a case report

Background: Multiple thrombi are likely to develop in Coronavirus Disease 2019 (COVID-19) patients. Hence, achieving successful outcomes following catheterization becomes quite challenging in such patients. Case presentation: We report a challenging case of a 36-year-old female with ST-Segment Elevation Myocardial Infarction (STEMI). Coronary angiography revealed multiple irregularities in the coronary tree as well as thrombi. Although computed tomography imaging of the thorax was normal, reverse transcription-polymerase chain reaction (RT-PCR) confirmed the diagnosis of COVID-19. The outcome was good TIMI flow after a successful Primary Angioplasty in Acute Myocardial Infarction (PAMI), and the patient was isolated and then switched to oral anticoagulants (clopidogrel) for dual antiplatelet therapy (DAPT) therapy.  Conclusion: This case emphasizes the management of a COVID-19 patient for PAMI

Recent Progress in Processing Functionally Graded Polymer Foams.

Polymer foams are an important class of engineering material that are finding diverse applications, including as structural parts in automotive industry, insulation in construction, core materials for sandwich composites, and cushioning in mattresses. The vast majority of these manufactured foams are homogeneous with respect to porosity and structural properties. In contrast, while cellular materials are also ubiquitous in nature, nature mostly fabricates heterogeneous foams, e.g., cellulosic plant stems like bamboo, or a human femur bone. Foams with such engineered porosity distribution (graded density structure) have useful property gradients and are referred to as functionally graded foams. Functionally graded polymer foams are one of the key emerging innovations in polymer foam technology. They allow enhancement in properties such as energy absorption, more efficient use of material, and better design for specific applications, such as helmets and tissue restorative scaffolds. Here, following an overview of key processing parameters for polymer foams, we explore recent developments in processing functionally graded polymer foams and their emerging structures and properties. Processes can be as simple as utilizing different surface materials from which the foam forms, to as complex as using microfluidics. We also highlight principal challenges that need addressing in future research, the key one being development of viable generic processes that allow (complete) control and tailoring of porosity distribution on an application-by-application basis

Characterisation and optimisation of the mechanical performance of plant fibre composites for structural applications

Plant fibres, perceived as environmentally sustainable substitutes to E-glass, are increasingly being employed as reinforcements in polymer matrix composites. However, despite the promising technical properties of cellulose-based fibres and the historic use of plant fibre composites (PFRPs) in load-bearing components, the industrial uptake of PFRPs in structural applications has been limited. In developing PFRPs whose mechanical properties are well-characterised, optimised and well-predicted, this thesis addresses the question: Can PFRPs replace E-glass composites (GFRPs) in structural applications? Ensuring that the highest reinforcement potential is exploited, this research examines the mechanical properties of aligned PFRPs based on bast fibre yarns/rovings and thermoset matrices. Although aligned GFRPs are found to outperform aligned PFRPs in terms of absolute mechanical properties, PFRPs reinforced with flax rovings exhibit exceptional properties, with a back-calculated fibre tensile modulus of up to 75 GPa and fibre tensile strength of about 800 MPa. To identify the processing window which produces composites with useful properties, the minimum, critical and maximum fibre volume fraction of PFRPs have been determined, and compared to that of synthetic fibre reinforced composites. The effect of fibre volume fraction on the physical and tensile properties of aligned PFRPs has also been investigated. Furthermore, micro-mechanical models have been developed and experimentally validated, to reliably predict the effect of (mis)orientation, in the forms of yarn twist/construction and off-axis loading, on the tensile properties of aligned PFRPs. To provide a complete set of fatigue data on aligned PFRPs, the effect of various composite parameters on PFRP cyclic-loading behaviour has been illustrated through S-N lifetime diagrams. A constant-life diagram has also been generated to enable the fatigue design and life prediction of a PFRP component. At each stage, the fatigue performance of PFRPs has been compared to that of GFRPs. Finally, in directly addressing the main theme, this thesis adopts a novel comparative case study approach to investigate the manufacture and mechanical testing of full-scale 3.5-meter composite rotor blades (suitable for 11 kW turbines) built from flax/polyester and E-glass/polyester. The study claims that under current market conditions, optimised plant fibre reinforcements are a structural, but not low-cost or sustainable, alternative to conventional E-glass reinforcements

Characterisation and optimisation of the mechanical performance of plant fibre composites for structural applications

Plant fibres, perceived as environmentally sustainable substitutes to E-glass, are increasingly being employed as reinforcements in polymer matrix composites. However, despite the promising technical properties of cellulose-based fibres and the historic use of plant fibre composites (PFRPs) in load-bearing components, the industrial uptake of PFRPs in structural applications has been limited. In developing PFRPs whose mechanical properties are well-characterised, optimised and well-predicted, this thesis addresses the question: Can PFRPs replace E-glass composites (GFRPs) in structural applications? Ensuring that the highest reinforcement potential is exploited, this research examines the mechanical properties of aligned PFRPs based on bast fibre yarns/rovings and thermoset matrices. Although aligned GFRPs are found to outperform aligned PFRPs in terms of absolute mechanical properties, PFRPs reinforced with flax rovings exhibit exceptional properties, with a back-calculated fibre tensile modulus of up to 75 GPa and fibre tensile strength of about 800 MPa. To identify the processing window which produces composites with useful properties, the minimum, critical and maximum fibre volume fraction of PFRPs have been determined, and compared to that of synthetic fibre reinforced composites. The effect of fibre volume fraction on the physical and tensile properties of aligned PFRPs has also been investigated. Furthermore, micro-mechanical models have been developed and experimentally validated, to reliably predict the effect of (mis)orientation, in the forms of yarn twist/construction and off-axis loading, on the tensile properties of aligned PFRPs. To provide a complete set of fatigue data on aligned PFRPs, the effect of various composite parameters on PFRP cyclic-loading behaviour has been illustrated through S-N lifetime diagrams. A constant-life diagram has also been generated to enable the fatigue design and life prediction of a PFRP component. At each stage, the fatigue performance of PFRPs has been compared to that of GFRPs. Finally, in directly addressing the main theme, this thesis adopts a novel comparative case study approach to investigate the manufacture and mechanical testing of full-scale 3.5-meter composite rotor blades (suitable for 11 kW turbines) built from flax/polyester and E-glass/polyester. The study claims that under current market conditions, optimised plant fibre reinforcements are a structural, but not low-cost or sustainable, alternative to conventional E-glass reinforcements

Mapping the light scattering distribution in a three-phase photopolymer resin system to predict cured dimensions

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An unusual presentation of primary renal lymphoma: A case report

Lymphomatous involvement of the kidney is often seen as a part of the disseminated disease but primary renal lymphoma is very rare. It is essential to differentiate between renal cell carcinoma and renal lymphoma in patients presenting with renal masses. The prognosis is usually poor with a median survival less than a year. We present the case of a 81-year-old male who presented with type B symptoms and was diagnosed to have primary lymphoma of the kidney and discuss briefly about the primary renal lymphoma

Transdisciplinary top-down review of hemp fibre composites: from an advanced product design to crop variety selection

Given the vast amount of available research in the area of natural fibre composites, a significant step forward in the development of next-generation plant fibre-based products would be to devise a framework for rational design. The authors use a top-down approach, starting with an example final product to define the product specifications for high-performance hemp fibre-reinforced composites. Thereafter, all process steps are critically analysed: from textile preform and reinforcement yarn production, to fibre extraction and the agricultural process chain, to the microbiology of field retting, to cultivation and selection of crop variety. The aim of the analysis is to determine how far the current state of knowledge and process technologies are in order to use hemp fibres in high-performance composites. Based on this critical evaluation of the state-of-the-art, it can be stated that hemp will be found in high-performance composites in the short-to-medium term. There is, however, a need for performance optimisation especially through the selection of crop variety, best practices in retting, and effective fibre extraction methods to obtain more consistent fibre qualities suitable for reinforcement spinning and composite preform manufacturing processes

Multi-material printing of thermoplastic and highly filled resin materials

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Use of dorsalis pedis artery flap in coverage of distal lower leg defects

Soft tissue defect in the distal one third of leg have always posed a challenge for reconstructive surgeons. Such wounds are difficult to manage due the tenuous blood supply, limited subcutaneous cover over the tendons and bones. The aim of our study is to investigate the outcome of Dorsalis pedis artery flap for the coverage of such defects. In the present study, we share our clinical experience with the use of dorsalis pedis artery flap for the coverage of defect in the distal one third leg. This is a series of 4 cases where dorsalis pedis artery flap was used to cover lower one third defect. One case had focal squamous cell carcinoma due to long standing post burns contracture in distal one third of leg anteriorly. Other 3 cases had chronic non healing ulcer in the malleolar region. Patient outcome was assessed according to patients’ age distribution, duration of surgery, hospital stay, and post-operative complications. All 4 patients had excellent outcome with no major donor site complications, infection, and graft loss. Donor site was closed with split thickness skin graft. One patient developed a minor raw area over the dorsum of foot which healed secondarily. Although a potential risk in applying this flap is insufficient venous drainage, no problems with blood inflow or outflow were encountered in the present case series. The flaps survived, and the patient had good postoperative outcome. Hence dorsalis pedis flap can be used for the coverage of the distal foot as a good option