Surgical treatment of giant cardiac aneurysm with pseudoaneurysm in a colon carcinoma patient

Left ventricular pseudoaneurysm is a rare and lethal condition associated with a high risk of rapid enlargement and rupture. It develops after transmural myocardial infarction (MI), cardiac surgery, trauma, or infection. When a left ventricular pseudoaneurysm is detected, surgical repair is recommended due to the high possibility of rupture. In this report, we present surgical treatment of a giant cardiac pseudoaneurysm that occurred after MI in a colon carcinoma patient

Semantic Text Compression for Classification

We study semantic compression for text where meanings contained in the text are conveyed to a source decoder, e.g., for classification. The main motivator to move to such an approach of recovering the meaning without requiring exact reconstruction is the potential resource savings, both in storage and in conveying the information to another node. Towards this end, we propose semantic quantization and compression approaches for text where we utilize sentence embeddings and the semantic distortion metric to preserve the meaning. Our results demonstrate that the proposed semantic approaches result in substantial (orders of magnitude) savings in the required number of bits for message representation at the expense of very modest accuracy loss compared to the semantic agnostic baseline. We compare the results of proposed approaches and observe that resource savings enabled by semantic quantization can be further amplified by semantic clustering. Importantly, we observe the generalizability of the proposed methodology which produces excellent results on many benchmark text classification datasets with a diverse array of contexts.Comment: Appeared in IEEE ICC 2023 2nd International Workshop on Semantic Communication

Supporting Custom Instructions with the LLVM Compiler for RISC-V Processor

The rise of hardware accelerators with custom instructions necessitates custom compiler backends supporting these accelerators. This study provides detailed analyses of LLVM and its RISC-V backend, supplemented with case studies providing end-to-end overview of the mentioned transformations. We discuss that instruction design should consider both hardware and software design space. The necessary compiler modifications may mean that the instruction is not well designed and need to be reconsidered. We discuss that RISC-V standard extensions provide exemplary instructions that can guide instruction designers. In this study, the process of adding a custom instruction to compiler is split into two parts as Assembler support and pattern matching support. Without pattern matching support, conventional software requires manual entries of inline Assembly for the accelerator which is not scalable. While it is trivial to add Assembler support regardless of the instruction semantics, pattern matching support is on the contrary. Pattern matching support and choosing the right stage for the modification, requires the knowledge of the internal transformations in the compiler. This study delves deep into pattern matching and presents multiple ways to approach the problem of pattern matching support. It is discussed that depending on the pattern's complexity, higher level transformations, e.g. IR level, can be more maintainable compared to Instruction Selection phase.Comment: Electronics and Communication Engineering B.Sc. Graduation Project. Source can be found in https://github.com/eymay/Senior-Design-Projec

A simple heart valve replacement technique which improves surgical time

Aim of the study: Different heart valve replacement techniques have been described in the literature. In the present study, a simple and very fast heart valve replacement technique is presented. Material and methods: In a two-year period, 87 patients with the diagnosis of mitral valve disease, aortic valve disease or combined valve disease underwent valve replacement performed by the same surgeon. In this technique, the valve was implanted with the valve clamped to the surgical dressing without the assistant holding it. Patients with coexisting surgical pathologies were excluded from the study. A control group was created among the patients who were operated on during the same time period by different surgeons with the assistant holding the prosthesis. Control group operations were done by conventional valve holding and suturing techniques. Results: Mean age of the patients was 61.6 ± 3.2 years. Mitral valve replacement (MVR) was done to 51 patients, aortic valve replacement (AVR) to 12 patients and both aortic and MVR to 24 patients. Aortic cross clamp duration was 30.7 ± 3.3 min for MVR, 34.8 ± 6.2 min for AVR and 69.1 ± 6.1 min for both valve replacements. Aortic clamping durations were significantly higher in the conventional implantation technique. Discussion: The described technique has many advantages such as short myocardial ischemia duration, better exposure of the surgical field and facilitation of assistance. © 2014 Termedia Sp. z o.o. All rights reserved

Implementation of an OFDM based underwater acoustic modem

Ankara : The Department of Electrical and Electronics Engineering and the Graduate School of Engineering and Sciences of Bilkent University, 2011.Thesis (Master's) -- Bilkent University, 2011.Includes bibliographical references leaves 52-55.In this thesis we designed and implemented an underwater acoustic (UWA) communication system employing multicarrier modulation in the form of orthogonal frequency division multiplexing (OFDM). UWA communication became more popular as there has been a growing interest in transmitting real-time data, such as video and sonar images. There are many applications where these transmissions are used. These applications are underwater wireless sensor networks(UWSN) and unmanned underwater vehicles (UUVs) for military and scientific purposes. Therefore, building an efficient UWA communication system which has a high data rate can improve these applications’ performance signifi- cantly. Currently, many underwater communication systems use single carrier modulation which have limited data rate due to complexity of their receivers, as frequency selectivity of the channel increases when the symbol rate increases, so we preferred to use multicarrier modulation in UWA communication in order to increase data rate of our system. In this thesis, we considered a system that uses zero-padded (ZP) OFDM modulation. Based on ZP-OFDM, we used a receiver model that performs pilot-tone based channel estimation, carrier frequency offset compensation based on least squares (LS) fitting error or null subcarriers if they occur and data demodulation for each OFDM block individually. We used MATLAB environment for implementing our system. The MATLAB scripts generate a data burst that contains OFDM blocks, and then it is transmitted to the hardware from a laptop by using a Data Acquisition (DAQ) Card. At the other side of the system, the receiver laptop gets the data by using a DAQ Card. As the data is received, MATLAB scripts are used for demodulating it. As we built our system, we performed underwater experiments at Bilkent Lake Facility to investigate its performance in a real UWA channel. In our test, a data rate of 13.92 kbps has been achieved with quadrature phase shift keying (QPSK) modulation while the bit-error-rate (BER) was less then 9x10−2 without using any coding.Demirörs, EmrecanM.S

An extensive calcified left ventricular aneurysm: Case report

A calcified left ventricular aneurysm (CLVA) is a rare, serious complication of acute myocardial infarction. It can lead to angina pectoris, thromboembolism of ventricular origin, ventricular arrhythmia, ventricular pseudoaneurysm or rupture, progressively enlarging aneurysms, congestive heart failure, and death. Treatment is surgical for symptomatic or asymptomatic LVAs larger than 5 cm, particularly when there is comorbid coronay artery disease. Its standard treatment is a ventriculoplasty and aneurysmectomy using the Dor technique. The aim of surgical treatment of an LVA is to reduce oxygen consumption in the LV by reducing end-diastolic volume (EDV), creating the ideal ventricle geometry, and preventing thrombus formation. The surgical results are often good. This article presents a patient with CLVA in whom we performed surgery. Copyright © 2016 by Türkiye Klinikleri

Surgical pitfalls of minimally invasive direct coronary artery bypass procedure from the viewpoint of a surgeon in the learning curve

Introduction: Minimally invasive direct coronary artery bypass grafting (MIDCAB) offers arterial revascularization of the left anterior descending (LAD) coronary artery especially in lesions unsuitable for percutaneous coronary interventions. By avoidance of sternotomy and cardiopulmonary bypass its invasiveness is less than that of conventional bypass surgery. Aim: We in this study discuss our surgical experience in the MIDCAB procedure. Material and methods: Thirteen patients were operated on with the MIDCAB procedure. The inclusion criteria for MIDCAB were pure LAD disease totally occluded or severely stenotic. Patient demographics and preoperative and postoperative data were analyzed. Results: Mean age of the patients was 60.0 ±8.6 years. Patients' preoperative and postoperative levels of cardiac CK-MB (creatine kinase MB) were not significantly different (p = 0.993). However, cardiac troponin I (p < 0.001), hemoglobin (p < 0.001) and hematocrit (p < 0.001) were significantly different. No perioperative myocardial infarctions or cerebrovascular accidents were seen. The patients were discharged at a mean day of 4.77 with oral antiaggregant therapy. No mortality was seen in the study population. Conclusions: Minimally invasive direct coronary artery bypass is associated with few perioperative complications. Minimally invasive direct coronary artery bypass in our experience is a very good option for single vessel LAD disease

A Hybrid MAC Protocol with Channel-dependent Optimized Scheduling for Clustered Underwater Acoustic Sensor Networks

We propose a novel optimal time slot allocation scheme for clustered underwater acoustic sensor networks that leverages physical (PHY) layer information to minimize the energy consumption due to unnecessary retransmissions thereby improving network lifetime and throughput. To reduce the overhead and the computational complexity, we employ a two-phase approach where: (i) each member node takes a selfish decision on the number of time slots it needs during the next intra-cluster cycle by solving a Markov decision process (MDP), and (ii) the cluster head optimizes the scheduling decision based on the channel quality and an urgency factor. To conserve energy, we use a hybrid medium access scheme, i.e., time division multiple access (TDMA) for the intra-cluster communication phase and carrier sense multiple access with collision avoidance (CSMA/CA) for the cluster head-sink communication phase. The proposed MAC protocol is implemented and tested on a real underwater acoustic testbed using SM-75 acoustic modems by Teledyne Benthos. Simulations illustrate an improvement in network lifetime. Additionally, simulations demonstrate that the proposed scheduling scheme with urgency factor achieves a throughput increase of 28 % and improves the reliability by up to 25 % as compared to the scheduling scheme that neither use MDP nor optimization. Furthermore, testbed experiments show an improvement in throughput by up to 10 % along with an improvement in reliability. 1