43 research outputs found

    Mobile Human Ad Hoc Networks: A Communication Engineering Viewpoint on Interhuman Airborne Pathogen Transmission

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    Pathogens such as viruses and bacteria play a vital role in human life, since they cause infectious diseases which can lead to epidemics. Recent coronavirus disease 2019 epidemic has shown that taking effective prevention measures such as wearing masks are important to reduce the human deaths and side effects of the epidemic. It is therefore requisite to accurately model the spread of infectious diseases whose one of the most crucial routes of transmission is airborne transmission. The transmission models in the literature are proposed independently from each other, at different scales and by the researchers from various disciplines. Thus, there is a need to merge all these research attempts. To this end, we propose a communication engineering approach that melts different disciplines such as epidemiology, biology, medicine, and fluid dynamics in the same pot to model airborne pathogen transmission among humans. In this approach, we introduce the concept of mobile human ad hoc networks (MoHANETs). This concept exploits the similarity of airborne transmission-driven human groups with mobile ad hoc networks and uses molecular communication as the enabling paradigm. The aim of this article is to present a unified framework using communication engineering, and to highlight future research directions for modeling the spread of infectious diseases among humans through airborne pathogen transmission. In this article, we first review the airborne pathogen transmission mechanisms. Then, the MoHANET is given with a layered structure. In these layers, the infectious human emitting pathogen-laden droplets through air and the exposed human to these droplets are considered as the transmitter and receiver, respectively. Moreover, the experimental methods for the proposed approach are reviewed and discussed.Comment: 7 pages, 6 figures, submitted to IEEE Communications Magazine Feature Topic on Nano-Networking for Nano-, Micro-, and Macro-Scale Application

    Localization of a Passive Source with a Sensor Network based Experimental Molecular Communication Platform

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    In a practical molecular communication scenario such as monitoring air pollutants released from an unknown source, it is essential to estimate the location of the molecular transmitter (TX). This paper presents a novel Sensor Network-based Localization Algorithm (SNCLA) for passive transmission by using a novel experimental platform which mainly comprises a clustered sensor network (SN) with 2424 sensor nodes and evaporating ethanol molecules as the passive TX. In SNCLA, a Gaussian plume model is employed to derive the location estimator. The parameters such as transmitted mass, wind velocity, detection time, and actual concentration are calculated or estimated from the measured signals via the SN to be employed as the input for the location estimator. The numerical results show that the performance of SNCLA is better for stronger winds in the medium. Our findings show that evaporated molecules do not propagate homogeneously through the SN due to the presence of the wind. In addition, our statistical analysis based on the measured experimental data shows that the sensed signals by the SN have a log-normal distribution, while the additive noise follows a Student's t-distribution in contrast to the Gaussian assumption in the literature

    A Hardware-Oriented Dynamically Adaptive Disparity Estimation Algorithm and its Real-Time Hardware

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    The computational complexity of disparity estimation algorithms and the need of large size and bandwidth for the external and internal memory make the real-time processing of disparity estimation challenging, especially for High Resolution (HR) images. This paper proposes a hardware-oriented adaptive window size disparity estimation (AWDE) algorithm and its real time reconfigurable hardware implementation that targets HR video with high quality disparity results. The proposed algorithm is a hybrid solution involving the Sum of Absolute Differences and the Census cost computation methods to vote and select the best suitable disparity candidates. It utilizes a pixel intensity based refinement step to remove faulty disparity computations. The AWDE algorithm dynamically adapts the window size considering the local texture of the image to increase the disparity estimation quality. The proposed reconfigurable hardware of the AWDE algorithm enables handling 60 frames per second on Virtex-5 FPGA at a 1024×768 XGA video resolution for a 120 pixel disparity range

    Seismic load tests on exterior beam-column connections of existing RC structures

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    U radu su izneseni prijedlozi za poboljšanje svojstava spojeva greda-stup postojećih AB konstrukcija uslijed potresnog djelovanja. Analizirana je uporaba betona niske čvrstoće, glatkog armaturnog čelika bez spona u spojevima te je ispitano ponašanje spojeva u uvjetima pod cikličnim opterećenjem. U okviru eksperimentalnog istraživanja proizvedeno je i ispitano pet uzoraka s različitim rasporedom armature. Na temelju rezultata zaključeno je da su kritični parametri koji određuju svojstva postojećih konstrukcija, raspored spona u spojevima i upotreba kuka za sidrenje uzdužne armature koje su savijene pod kutom od najmanje 90°.Suggestions for improving seismic performance of beam-column connections of the existing RC structures are presented in this paper. The use of low-strength concrete with plain bars without stirrups in joints is analysed, and behaviour of joints in the aforementioned conditions under cyclic load is investigated. Five specimens with different reinforcement configurations were produced and tested in the experimental process. Based on results, it was concluded that critical parameters for the performance of existing structures are: stirrup arrangement in joints, and the use of at least 90-degree hooks in longitudinal reinforcement of beams

    Prognostic factors for regorafenib treatment in patients with refractory metastatic colorectal cancer: A real-life retrospective multi-center study

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    Regorafenib, an oral multikinase inhibitor, has improved survival in metastatic colorectal cancer (mCRC) patients who have progressed on standard therapies. Our study aimed to evaluate prognostic factors influencing regorafenib treatment and assess the optimal dosing regimen in a real-life setting. We retrospectively analysed 263 patients with mCRC from multiple medical oncology clinics in Turkey. Treatment responses and prognostic factors for survival were evaluated using univariate and multivariate analysis. Of the patients, 120 were male, and 143 were female; 28.9% of tumors were located in the rectum. RAS mutations were present in 3.0% of tumors, while BRAF, K-RAS, and N-RAS mutations were found in 3.0%, 29.7%, and 25.9% of tumor tissues, respectively. Dose escalation was preferred in 105 (39.9%) patients. The median treatment duration was 3.0 months, with an objective response rate (ORR) of 4.9%. Grade ≥ 3 treatment-related toxicity occurred in 133 patients, leading to discontinuation, interruption, and modification rates of 50.6%, 43.7%, and 79.0%, respectively. Median progression-free survival (PFS) and overall survival (OS) were 3.0 and 8.1 months, respectively. RAS/RAF mutation (hazard ratio [HR] 1.5, 95% confidence interval [CI] 1.1-2.3; P = 0.01), pretreatment carcinoembryonic antigen (CEA) levels (HR 1.6, 95% CI 1.1-2.3; P = 0.008), and toxicity-related treatment interruption or dose adjustment (HR 1.6, 95% CI 1.1-2.4; P = 0.01) were identified as independent prognostic factors for PFS. Dose escalation had no significant effect on PFS but was associated with improved OS (P < 0.001). Independent prognostic factors for OS were the initial TNM stage (HR 1.3, 95% CI 1.0-1.9; P = 0.04) and dose interruption/adjustment (HR 0.4, 95% CI 0.2-0.9; P = 0.03). Our findings demonstrate the efficacy and safety of regorafenib. Treatment line influences the response, with dose escalation being more favorable than adjustment or interruption, thus impacting survival

    Burnout among surgeons before and during the SARS-CoV-2 pandemic: an international survey

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    Background: SARS-CoV-2 pandemic has had many significant impacts within the surgical realm, and surgeons have been obligated to reconsider almost every aspect of daily clinical practice. Methods: This is a cross-sectional study reported in compliance with the CHERRIES guidelines and conducted through an online platform from June 14th to July 15th, 2020. The primary outcome was the burden of burnout during the pandemic indicated by the validated Shirom-Melamed Burnout Measure. Results: Nine hundred fifty-four surgeons completed the survey. The median length of practice was 10&nbsp;years; 78.2% included were male with a median age of 37&nbsp;years old, 39.5% were consultants, 68.9% were general surgeons, and 55.7% were affiliated with an academic institution. Overall, there was a significant increase in the mean burnout score during the pandemic; longer years of practice and older age were significantly associated with less burnout. There were significant reductions in the median number of outpatient visits, operated cases, on-call hours, emergency visits, and research work, so, 48.2% of respondents felt that the training resources were insufficient. The majority (81.3%) of respondents reported that their hospitals were included in the management of COVID-19, 66.5% felt their roles had been minimized; 41% were asked to assist in non-surgical medical practices, and 37.6% of respondents were included in COVID-19 management. Conclusions: There was a significant burnout among trainees. Almost all aspects of clinical and research activities were affected with a significant reduction in the volume of research, outpatient clinic visits, surgical procedures, on-call hours, and emergency cases hindering the training. Trial registration: The study was registered on clicaltrials.gov "NCT04433286" on 16/06/2020
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