Para-cardiac Inflammatory Mass Compressing the Heart: A possible association with COVID-19

Infection with the SARS-CoV-2 virus causes coronavirus disease 2019 (COVID-19). COVID-19 usually affects the lungs but may also involve other organs such as the heart. We report a case of a para-cardiac mass in a previously healthy 45-year-old man who developed persistent dyspnea following SARS-CoV-2 infection. The patient underwent cardiac surgery since the mass was attached to the pericardium and was causing constrictive pericarditis. The pathology report indicated an inflammatory pattern for the mass. Based on our knowledge there has been no previous report of developing a para-cardiac inflammatory mass after SARS-CoV-2 infection. In conclusion, we would like to increase awareness regarding the possibility of developing a para-cardiac inflammatory mass following COVID-19. Keywords: SARS-CoV-2; Pericarditis; Constrictive pericarditis; COVID-19; Cardiac tumor; Mediastinal tumor

The effect of stacking sequence and ply orientation on the mechanical properties of pineapple leaf fibre PALF/carbon hybrid laminate composites

In this paper, the effects of stacking sequence and ply orientation on the mechanical properties of pineapple leaf fibre (PALF)/carbon hybrid laminate composites were investigated. The hybrid laminates were fabricated using a vacuum infusion technique in which the stacking sequences and ply orientations were varied, which were divided into the categories of cross-ply symmetric, angle-ply symmetric, and symmetric quasi-isotropic. The results of tensile and flexural tests showed that the laminate with interior carbon plies and ply orientation [0°, 90°] exhibited the highest tensile strength (187.67 MPa) and modulus (5.23 GPa). However, the highest flexural strength (289.46 MPa) and modulus (4.82 GPa) were recorded for the laminate with exterior carbon plies and the same ply orientation. The fracture behaviour of the laminates was determined by using scanning electron microscopy, and the results showed that failure usually initiated at the weakest PALF layer. The failure modes included fibre pull-out, fibre breaking, matrix crack, debonding and delamination

The effect of stacking sequence on fatigue behaviour of hybrid pineapple leaf fibre/carbon-fibre-reinforced epoxy composites

This study examined the fatigue behaviour of pineapple leaf fibre/carbon hybrid laminate composites under various stacking sequences. The vacuum infusion technique was used to fabricate the symmetric quasi-isotropic oriented laminates, in which the stacking was varied. The laminate was tested under static and fatigue tensile load according to ASTM D3039-76 and ASTM D3479-96, respectively. Maximum tensile strength and modulus of 119.34 MPa and 6.86 GPa, respectively, were recorded for the laminate with external PALF ply and internal carbon ply oriented at [± 45°2, 0°/90°2]s (PCCP_45090). The fatigue tests showed that PCCP_45090 and CPPC_09045 (with internal PALF ply and external carbon ply oriented at [0°/90°2, ± 45°2]s) exhibited a higher useful life, especially at the high-stress level of the ultimate tensile strength. The normalised stress against the number of cycles showed that the stacking sequences of different ply orientations affected the fatigue behaviour more than the stacking sequences of the material. The laminate stacking sequence significantly affected the hysteresis energy and stiffness evolution. The scanning electron microscopy images showed that the fatigue failure modes included fibre pull-out, fibre breakage, matrix cracking, debonding, and delamination. The study concluded that PCCP_45090 exhibited an outstanding fatigue performance

The incidence of in-hospital atrial fibrillation after coronary artery bypass grafting using ventricular and atrial pacing

BACKGROUND: Atrial fibrillation (AF) after coronary artery bypass graft (CABG) surgery is a common problem. In this study, we sought to evaluate the safety and tolerance of continuous atrial pacing after CABG. We hypothesized that a strategy of temporary atrial pacing after CABG would reduce the incidence of postoperative AF. METHODS: During 2012, CABG candidates over 18 years of age at Sina Hospital (Isfahan, Iran) were recruited. Before surgery, the participants were randomly assigned to two groups of ventricular pacing and left atrial ventricular pacing (atrial pacing). The primary end point of the study was the initial occurrence of AF or atrial flutter with a ventricular rate greater than 100 beats per minute for 10 consecutive minutes or completion of the 48-hour monitoring period. RESULTS: We evaluated 64 consecutive CABG candidates with sinus rhythm. They were allocated to two groups of ventricular pacing and atrial ventricular pacing (n = 32 in each group). Three patients in the ventricular pacing group (10%) and six in the atrial ventricular pacing group (22%) had sustained AF during the first 48 hours after CABG (P = 0.18 according to Fisher’s exact test). CONCLUSION: Continuous atrial pacing in the postoperative setting is safe and well-tolerated. In this study, we found that temporary atrial pacing increased the frequency of postoperative AF. Since the difference between the two groups was not significant, larger studies are required to determine the exact relation between pacing method and AF.   Keywords: Atrial Fibrillation, Coronary Artery Bypass Graft, Atrial Pacin

Effects of Ply Orientations and Stacking Sequences on Impact Response of Pineapple Leaf Fibre (PALF)/Carbon Hybrid Laminate Composites

This study investigated the impact response behaviours of pineapple leaf fibre (PALF)/carbon hybrid laminate composites for different ply orientations and stacking sequences. The laminates were manufactured using a vacuum infusion approach with various stacking sequences and ply orientations classified as symmetric quasi-isotropic, angle-ply symmetric, and cross-ply symmetric. The laminates were analysed using an IMATEK IM10 drop weight impact tester with an increment of 5 J until the samples were perforated. This investigation reveals that the overall impact properties of PALF and carbon as reinforcements were improved by a beneficial hybridised effect. The laminates with an exterior carbon layer can withstand high impact energy levels up to 27.5 J. The laminate with different stacking sequences had a lower energy transfer rate and ruptured at higher impact energy. The laminates with ply orientations of [0°/90°] and [±45°]8 exhibited 10% to 30% better energy absorption than those with ply orientations of [±45°2, 0°/90°2]s and [0°/90°2, ±45°2]s due to energy being readily transferred within the same linear ply orientation. Through visual inspection, delamination was observed to occur at the interfaces of different stacking sequences and ply orientations

The transcription factor ERG recruits CCR4-NOT to control mRNA decay and mitotic progression.

Control of mRNA levels, a fundamental aspect in the regulation of gene expression, is achieved through a balance between mRNA synthesis and decay. E26-related gene (Erg) proteins are canonical transcription factors whose previously described functions are confined to the control of mRNA synthesis. Here, we report that ERG also regulates gene expression by affecting mRNA stability and identify the molecular mechanisms underlying this function in human cells. ERG is recruited to mRNAs via interaction with the RNA-binding protein RBPMS, and it promotes mRNA decay by binding CNOT2, a component of the CCR4-NOT deadenylation complex. Transcriptome-wide mRNA stability analysis revealed that ERG controls the degradation of a subset of mRNAs highly connected to Aurora signaling, whose decay during S phase is necessary for mitotic progression. Our data indicate that control of gene expression by mammalian transcription factors may follow a more complex scheme than previously anticipated, integrating mRNA synthesis and degradation