3,981 results on '"CHAABAN, A."'
Search Results
52. The Influence of an SQD-based Practicum Experience on Student Teachers' Tpack-practical Development: Opportunities and Challenges
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Chaaban, Youmen and Sawalhi, Rania
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- 2023
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53. An Eye on the Future: Student Plans for Higher Education in Qatar
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Abdellatif Sellami, Youmen Chaaban, and Saba Mansoor Qadhi
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Educational aspirations ,High school students ,Qatar ,Education (General) ,L7-991 - Abstract
Education is identified as very critical to the achievement of the goals that were specified as strategic to Qatar’s socio-economic progress and development. At the core of the country’s policy plans is the need to develop human capacity as is highlighted in the Qatar National Vision (QNV) 2030. Not surprisingly, education has been identified as a strategic key to achieving the goals outlined in the QNV 2030. The present exploratory study employed a quantitative research design in order to investigate the factors that are likely to influence the educational aspirations of Qatari students. Drawing on Social Cognitive Theory (SCT) and Attribution Theory (AT), this study sought to examine students’ aspirations for post-secondary education in Qatar. Data for this study were collected using the Qatar Education Study (QES) survey, which is a nationally representative survey involving K-12 students in the State of Qatar. The analysis of this study’s data revealed that personal and household characteristics play an important role in shaping post-secondary educational aspirations of student participants, including age, nationality, education and employment status, as well as parental influence. Based on the study’s results, statistically significant associations were observed between personal and household variables and students’ aspirations for higher education. This study concludes with relevant recommendations and proposes future studies to explore the potential impact of individual aptitude and contextual factors on student future academic plans.
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- 2024
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54. On Achievable Rates of Evenly-Spaced Discrete Uniform Distributions in the IM/DD Broadcast Channel
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Zhang, Zhenyu Charlus and Chaaban, Anas
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Computer Science - Information Theory - Abstract
In optical wireless communications, a broadcast channel (BC) employing intensity modulation and direct detection (IM/DD) is often modelled as a peak-constrained BC. A closed-form expression for its capacity region of the peak-constrained BC is not known. This paper presents an analytical capacity inner bound for the peak-constrained Gaussian BC achieved by a class of discrete input distribution, specifically, the evenly-spaced discrete uniform distribution (ESDU). In contrast to the continuous input distribution that provides the benchmark, ESDU is more promising in the application of peak-constrained Gaussian channels. The newly obtained capacity inner bound is easily-computable and is numerically shown to be tighter than the benchmark. Besides, we remark the newly developed analytical upper bound for the ESDU rate, which is tight in all tested settings., Comment: Accepted to be presented in IEEE Global Communications Conference (Globecom), 2022
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- 2022
55. User Association in User-Centric Hybrid VLC/RF Cell-Free Massive MIMO Systems
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Almehdhar, Ahmed, Obeed, Mohanad, Chaaban, Anas, and Zummo, Salam A.
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Computer Science - Information Theory ,Electrical Engineering and Systems Science - Signal Processing - Abstract
A continuous goal in all communication systems is to enhance the users experience and provide them with the highest possible data rates. Recently, the concept of cell-free massive MIMO (CF-mMIMO) systems has been considered to enhance the performance of systems that operate merely with Radio Frequency (RF) or visible light communication (VLC) technologies. In this paper, a hybrid VLC/RF cell-free massive MIMO system is proposed where an RF cell-free network and a VLC cell-free network coexist to serve users. The idea is to utilize the benefits of each network and balance the load aiming at maximizing the system's sum-rate. The system is evaluated using zero-forcing (ZF) precoding scheme. Two user association algorithms are proposed to assign users to either the VLC or the RF networks. In addition, two user-centric clustering approaches are proposed and evaluated. Simulation results show that the proposed association algorithms significantly outperform a random network association of users in terms of sum-rate. Results also show great potential for the proposed system compared to standalone cell-free networks., Comment: This version has been removed by arXiv administrators as the submitter did not have the right to agree to the license at the time of submission
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- 2022
56. Capacity Bounds for the Two-User IM/DD Interference Channel
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Zhang, Zhenyu and Chaaban, Anas
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Computer Science - Information Theory - Abstract
This paper studies the capacity of the two-user intensity-modulation/direct-detection (IM/DD) interference channel (IC), which is relevant in the context of multi-user optical wireless communications. Despite some known single-letter capacity characterizations for general discrete-memoryless ICs, a computable capacity expression for the IM/DD IC is missing. In this paper, we provide tight and easily computable inner and outer bounds for a general two-user IM/DD IC under peak and average optical intensity constraints. The bounds enable characterizing the asymptotic sum-rate capacity in the strong and weak interference regimes, as well as the generalized degrees of freedom (GDoF) in the symmetric case. Using the obtained bounds, the GDoF of the IM/DD IC is shown to have a `W' shape similar to the Gaussian IC with power constraints. The obtained bounds are also evaluated numerically in different interference regimes to show their tightness, and used to study the performance of on-chip and indoor OWC systems., Comment: To be published in IEEE Transactions on Communications
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- 2022
57. Decentralized Aggregation for Energy-Efficient Federated Learning via Overlapped Clustering and D2D Communications
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Al-Abiad, Mohammed S., Obeed, Mohanad, Hossain, Md. Jahangir, and Chaaban, Anas
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Computer Science - Information Theory - Abstract
Federated learning (FL) has emerged as a distributed machine learning (ML) technique to train models without sharing users' private data. In this paper, we propose a decentralized FL scheme that is called \underline{f}ederated \underline{l}earning \underline{e}mpowered \underline{o}verlapped \underline{c}lustering for \underline{d}ecentralized aggregation (FL-EOCD). The introduced FL-EOCD leverages device-to-device (D2D) communications and overlapped clustering to enable decentralized aggregation, where a cluster is defined as a coverage zone of a typical device. The devices located on the overlapped clusters are called bridge devices (BDs). In the proposed FL-EOCD scheme, a clustering topology is envisioned where clusters are connected through BDs, so as the aggregated models of each cluster is disseminated to the other clusters in a decentralized manner without the need for a global aggregator or an additional hop of transmission. Unlike the star-based FL, the proposed FL-EOCD scheme involves a large number of local devices by reusing the RRBs in different non-adjacent clusters. To evaluate our proposed FL-EOCD scheme as opposed to baseline FL schemes, we consider minimizing the overall energy-consumption of devices while maintaining the convergence rate of FL subject to its time constraint. To this end, a joint optimization problem, considering scheduling the local devices/BDs to the CHs and computation frequency allocation, is formulated, where an iterative solution to this joint problem is devised. Extensive simulations are conducted to verify the effectiveness of the proposed FL-EOCD algorithm over FL conventional schemes in terms of energy consumption, latency, and convergence rate., Comment: 15, 9 figures, Journal
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- 2022
58. Biomarkers of necrotizing enterocolitis in the era of machine learning and omics.
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Leiva, Tyler, Lueschow, Shiloh, Burge, Kathryn, Devette, Christa, Chaaban, Hala, and McElroy, Steven
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Infant ,Infant ,Newborn ,Humans ,Infant ,Premature ,Enterocolitis ,Necrotizing ,Artificial Intelligence ,Biomarkers ,Infant ,Newborn ,Diseases ,Machine Learning - Abstract
Necrotizing enterocolitis (NEC) continues to be a major cause of morbidity and mortality in preterm infants. Despite decades of research in NEC, no reliable biomarkers can accurately diagnose NEC or predict patient prognosis. The recent emergence of multi-omics could potentially shift NEC biomarker discovery, particularly when evaluated using systems biology techniques. Furthermore, the use of machine learning and artificial intelligence in analyzing this big data could enable novel interpretations of NEC subtypes, disease progression, and potential therapeutic targets, allowing for integration with personalized medicine approaches. In this review, we evaluate studies using omics technologies and machine learning in the diagnosis of NEC. Future implications and challenges inherent to the field are also discussed.
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- 2023
59. State-of-the-art review and update of in vivo models of necrotizing enterocolitis
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Bautista, Geoanna M, Cera, Anjali J, Chaaban, Hala, and McElroy, Steven J
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Paediatrics ,Biomedical and Clinical Sciences ,Rare Diseases ,Infant Mortality ,Preterm ,Low Birth Weight and Health of the Newborn ,Perinatal Period - Conditions Originating in Perinatal Period ,Pediatric ,Good Health and Well Being ,NEC = necrotizing enterocolitis ,animal model ,intestinal injury ,necrotizing/intestinal diseases/intestine ,preclinical (in vivo) studies ,Paediatrics and Reproductive Medicine ,Other Medical and Health Sciences - Abstract
NEC remains one of the most common causes of mortality and morbidity in preterm infants. Animal models of necrotizing enterocolitis (NEC) have been crucial in improving our understanding of this devastating disease and identifying biochemical pathways with therapeutic potential. The pathogenesis of NEC remains incompletely understood, with no specific entity that unifies all infants that develop NEC. Therefore, investigators rely on animal models to manipulate variables and provide a means to test interventions, making them valuable tools to enhance our understanding and prevent and treat NEC. The advancements in molecular analytic tools, genetic manipulation, and imaging modalities and the emergence of scientific collaborations have given rise to unique perspectives and disease correlates, creating novel pathways of investigation. A critical review and understanding of the current phenotypic considerations of the highly relevant animal models of NEC are crucial to developing novel therapeutic and preventative strategies for NEC.
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- 2023
60. A comparative study of machine learning approaches for an accurate predictive modeling of solar energy generation
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Chaaban, Alain K. and Alfadl, Najd
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- 2024
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61. Insulin amyloid morphology is encoded in H-bonds and electrostatics interactions ruling protein phase separation
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Lenton, Samuel, Chaaban, Hussein, Khaled, Mohammed, van de Weert, Marco, Strodel, Birgit, and Foderà, Vito
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- 2025
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62. Alternating Channel Estimation and Prediction for Cell-Free mMIMO with Channel Aging: A Deep Learning Based Scheme
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Obeed, Mohanad, Al-Eryani, Yasser, and Chaaban, Anas
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Computer Science - Information Theory ,Computer Science - Machine Learning - Abstract
In large scale dynamic wireless networks, the amount of overhead caused by channel estimation (CE) is becoming one of the main performance bottlenecks. This is due to the large number users whose channels should be estimated, the user mobility, and the rapid channel change caused by the usage of the high-frequency spectrum (e.g. millimeter wave). In this work, we propose a new hybrid channel estimation/prediction (CEP) scheme to reduce overhead in time-division duplex (TDD) wireless cell-free massive multiple-input-multiple-output (mMIMO) systems. The scheme proposes sending a pilot signal from each user only once in a given number (window) of coherence intervals (CIs). Then minimum mean-square error (MMSE) estimation is used to estimate the channel of this CI, while a deep neural network (DNN) is used to predict the channels of the remaining CIs in the window. The DNN exploits the temporal correlation between the consecutive CIs and the received pilot signals to improve the channel prediction accuracy. By doing so, CE overhead is reduced by at least 50 percent at the expense of negligible CE error for practical user mobility settings. Consequently, the proposed CEP scheme improves the spectral efficiency compared to the conventional MMSE CE approach, especially when the number of users is large, which is demonstrated numerically., Comment: 6 pages, 6 figures
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- 2022
63. Student Teachers' Perceptions of Factors Influencing Learner Agency Working in Teams in a STEAM-Based Course
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Chaaban, Youmen, Qadhi, Saba, and Du, Xiangyun
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The study adopted a sequential mixed-methods approach to investigate student teachers' learner agency in a teamwork setting at Qatar University. In the qualitative phase, a total of 10 student teachers enrolled in a course adopting a STEAM pedagogical approach participated in in-depth interviews. Qualitative analysis identified seven sources for practicing learner agency in teams. Using this data, the Learner Agency in Teamwork Settings survey was constructed. The survey was distributed to 108 student teachers taking the same course, which utilized an inquiry, problem solving, and digital-based learning design. Using exploratory and confirmatory factor analyses, four factors emerged, including: interest and motivation, teamwork self-efficacy, socio-cultural support, and team support. The findings have important educational implications for promoting student teachers' agency in similar educational contexts.
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- 2021
64. Teachers' Readiness for a Statewide Change to PjBL in Primary Education in Qatar
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Du, Xiangyun and Chaaban, Youmen
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This study investigated the readiness of teachers towards implementing project-based learning (PjBL), mandated by a top-down policy at the national level, in Qatari government primary schools. With multiple qualitative data, the study reported a lack of readiness among teachers at the initial stage of change. Despite good intentions, the change message was not successfully communicated to the change recipients, i.e., teachers. Teachers' lack of understanding of PjBL served as a major reason for difficulties encountered, including their low confidence in implementing PjBL and their inability to recognize the appropriateness or acknowledge its potential benefits. Nevertheless, teachers from a supportive school environment reported positive attitudes and perceptions of valence. Accordingly, system support and effective professional development are crucial for teacher readiness to implement PjBL.
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- 2020
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65. Security enhancement by intelligent reflecting surfaces for visible light communications
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Qian, Lei, Zhao, Linlin, Huang, Nuo, Chaaban, Anas, and Xu, Zhengyuan
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- 2024
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66. Baccharis essential oils from the Atlantic Forest as sources of natural pesticides
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Eccel, Camila, Zimmermann, Rubens Candido, Giraldi, Greissi Tente, Foerster, Luís Amilton, de Bitencourt Frasson, Vinícius, Chaaban, Amanda, do Amaral, Wanderlei, Sales Maia, Beatriz Helena L.N., Dos Santos, Elaine Fernanda, Poitevin, Carolina Gracia, and Martins, Carlos Eduardo Nogueira
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- 2024
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67. Improving dietary patterns in obese mice: Effects on body weight, adiposity, anhedonia-like behavior, pro-BDNF expression and 5-HT system
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Ferreira, Nicoly Bédia, Dias, Clarissa Tavares, Chaaban, Ana Flávia Alves, Beserra-Filho, José Ivo Araújo, Ribeiro, Alessandra Mussi, Lambertucci, Rafael Herling, and Mendes-da-Silva, Cristiano
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- 2024
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68. RIS-Aided Index Modulation for OFDM Systems: Analysis and Code Design for Flat-Fading Channels.
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Tong Zhang, Yikun Zou, Gang Wang 0021, Anas Chaaban, Gongliang Liu, and Julian Cheng
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- 2024
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69. Performance of Multi-RIS-Aided Cell-Free Massive MIMO: Do More RISs Always Help?
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Bayan Al-Nahhas, Mohanad Obeed, Anas Chaaban, and Md. Jahangir Hossain 0002
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- 2024
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70. Energy-Efficient Multi-Pair Computation for Intra Cell-Free Massive MIMO Communications.
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Mahmoud A. Hasabelnaby and Anas Chaaban
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- 2024
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71. Analysis of One-Bit Quantized Linear Precoding Schemes in Multi-Cell Massive MIMO Downlink.
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Qurrat-Ul-Ain Nadeem and Anas Chaaban
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- 2024
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72. Finite Blocklength Regime Performance of Downlink Large Scale Networks.
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Nourhan Hesham, Anas Chaaban, Hesham ElSawy, and Md. Jahangir Hossain 0002
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- 2024
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73. Rate Outage and Meta-Distribution for Uplink Networks in Finite Block-Length Regime.
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Nourhan Hesham, Hesham ElSawy, Md. Jahangir Hossain 0002, and Anas Chaaban
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- 2024
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74. Transformer Masked Autoencoders for Next-Generation Wireless Communications: Architecture and Opportunities.
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Abdullah Zayat, Mahmoud A. Hasabelnaby, Mohanad Obeed, and Anas Chaaban
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- 2024
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75. Contributors
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Abello, Eric H., primary, Abiri, Arash, additional, Adappa, Nithin D., additional, Ahmad, Meleha, additional, Almeida, Joao Paulo, additional, Alrasheed, Abdulaziz S., additional, Arrighi-Allisan, Annie, additional, Barton, Blair M., additional, Bastien, Amanda J., additional, Battaglia, Paolo, additional, Biousse, Valérie, additional, Bleier, Benjamin S., additional, Carrau, Ricardo L., additional, Castelnuovo, Paolo, additional, Chaaban, Mohamad R., additional, Chan, David, additional, Chemas-Velez, Maria Manuela, additional, Chen, Benson S., additional, Chou, Brian W., additional, Cote, David J., additional, Cutsforth-Gregory, Jeremy K., additional, Czaczkes, Camilla, additional, Dalfino, Gianluca, additional, Das, Paramita, additional, Junior de Andrade, Erion, additional, Filho, Leonardo de Macedo, additional, Eloy, Jean Anderson, additional, Evans, James J., additional, Fang, Christina H., additional, Filip, Peter, additional, Francis, Courtney E., additional, Gallia, Gary L., additional, Gardner, Paul A., additional, Gentili, Fred, additional, Georgalas, Christos, additional, Ginat, Daniel T., additional, Gogia, Angad S., additional, Govindaraj, Satish, additional, Grayson, Jessica W., additional, Gudis, David A., additional, Halderman, Ashleigh A., additional, Harvey, Richard J., additional, Hernandez, Stephen, additional, Higgins, Mamie, additional, Horowitz, Peleg Moshe, additional, Illing, Elisa A., additional, Ishii, Masaru, additional, Kamel, Peter, additional, Kang, Keiko M., additional, Karp, Emily, additional, Karsy, Michael J., additional, Kshettry, Varun R., additional, Kshirsagar, Rijul S., additional, Kuan, Edward C., additional, Lamarre, Eric, additional, Levy, Joshua M., additional, Link, Michael, additional, Little, Andrew S., additional, Liu, Ann, additional, Liu, James K., additional, Locatelli, Davide, additional, Luna, Licia P., additional, Mahomva, Chengetai, additional, McCulley, Timothy J., additional, Medina, Eduardo J., additional, Michael, Alex P., additional, Miglani, Amar, additional, Mihal, David, additional, Moe, Kris S., additional, Nadgir, Rohini, additional, Nicholson, Patrick, additional, Nyquist, Gurston G., additional, Oostra, Amanda, additional, Oswald, Aaron, additional, Palmer, James N., additional, Parsel, Sean M., additional, Patel, Prayag, additional, Petrauskas, Laura, additional, Porto, Edoardo, additional, Pradilla, Gustavo, additional, Prashant, Giyarpuram N., additional, Prevedello, Daniel, additional, Qureshi, Hannan A., additional, Rabinowitz, Mindy R., additional, Radovanovic, Ivan, additional, Ramanathan, Murugappan, additional, Rao, Shilpa M., additional, Ray, Amrita, additional, Rech, Matheus, additional, Recinos, Pablo F., additional, Barbero, J. Manuel Revuelta, additional, Rincon-Torroella, Jordina, additional, Rosen, Marc R., additional, Roxbury, Christopher R., additional, Ruggieri, Paul, additional, Safi, Chetan, additional, Santarelli, Griffin D., additional, Sarris, Christina E., additional, Schlosser, Rodney J., additional, Schwartz, Theodore H., additional, Shah, Janki, additional, Sindwani, Raj, additional, Snyderman, Carl H., additional, Sommerfeld, Connor, additional, Soriano, Roberto M., additional, Sreenath, Satyan B., additional, Stokken, Janalee, additional, Tabaee, Abtin, additional, Tang, Dennis M., additional, Timmons, Shelly D., additional, Ting, Jonathan, additional, Turri-Zanoni, Mario, additional, Vorster, Sarel J., additional, Vyskocil, Erich, additional, Warren, Zachary, additional, Watley, Duncan C., additional, White, Alexandra J., additional, Williams, Michael A., additional, Woodard, Troy D., additional, Woodworth, Bradford A., additional, Workman, Alan D., additional, Wormald, Peter-John, additional, Wrobel, Bozena B., additional, Zada, Gabriel, additional, Zanation, Adam, additional, Zhao, Jiawei, additional, and Zimmer, David I., additional
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- 2024
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76. Advances in endoscopic visualization and surgical navigation
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Junior de Andrade, Erion, primary, Mahomva, Chengetai, additional, Higgins, Mamie, additional, Sindwani, Raj, additional, Chaaban, Mohamad R., additional, and Kshettry, Varun R., additional
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- 2024
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77. Effects of a carbohydrate-reduced high-protein diet delivered with meal kits to Danish people with type 2 diabetes: protocol for a 12-month randomised controlled trial
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Sten Madsbad, Faidon Magkos, Jens J Holst, Esben Budtz-Jørgensen, Thure Krarup, Brice Ozenne, Luise H P Kopp, Christina M Søgaard-Hansen, Karen M Zachhau, Rasmus M Bastkjær, Barbara V Andersen, Derek V Byrne, Nora Chaaban, Trine B Klindt, Amirsalar Samkani, Mads J Skytte, and Mads N Thomsen
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Medicine - Abstract
Introduction The cornerstone in the management of type 2 diabetes (T2D) is lifestyle modification including a healthy diet, typically one in which carbohydrate provides 45%–60% of total energy intake (E%). Nevertheless, systematic reviews and meta-analyses of trials with low carbohydrate diets (which are increased in protein and/or fat) for T2D have found improved glycaemic control in the first months relative to comparator diets with higher carbohydrate content. Studies lasting ≥1 year are inconclusive, which could be due to decreased long-term dietary adherence. We hypothesise that glucometabolic benefits can be achieved following 12 months of carbohydrate-restricted dieting, by maximising dietary adherence through delivery of meal kits, containing fresh, high-quality ingredients for breakfast, dinner and snacks, combined with nutrition education and counselling.Methods and analysis This protocol describes a 12-month investigator-initiated randomised controlled, open-label, superiority trial with two parallel groups that will examine the effect of a carbohydrate-reduced high-protein (CRHP) diet compared with a conventional diabetes (CD) diet on glucometabolic control (change in glycated haemoglobin being the primary outcome) in 100 individuals with T2D and body mass index (BMI) >25 kg/m2. Participants will be randomised 1:1 to receive either the CRHP or the CD diet (comprised 30/50 E% from carbohydrate, 30/17 E% from protein and 40/33 E% from fat, respectively) for 12 months delivered as meal kits, containing foods covering more than two-thirds of the participants’ estimated daily energy requirements for weight maintenance. Adherence to the allocated diets will be reinforced by monthly sessions of nutrition education and counselling from registered clinical dietitians.Ethics and dissemination The trial has been approved by the National Committee on Health Research Ethics of the Capital Region of Denmark. The trial will be conducted in accordance with the Declaration of Helsinki. Results will be submitted for publication in international peer-reviewed scientific journals.Trial registration number NCT05330247.Protocol version The trial protocol was approved on 9 March 2022 (study number: H-21057605). The latest version of the protocol, described in this manuscript, was approved on 23 June 2023.
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- 2024
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78. A narrative review on the role of cytokines in the pathogenesis and treatment of familial Mediterranean fever: an emphasis on pediatric cases
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Ahlam Chaaban, Hasan Yassine, Razane Hammoud, Ruba Kanaan, Louna Karam, and José-Noel Ibrahim
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familial mediaterranean fever ,children ,cytokine ,treatment ,pathogenesis ,Pediatrics ,RJ1-570 - Abstract
Familial Mediterranean Fever (FMF) is a hereditary autoinflammatory disease characterized by an early onset of recurrent fever and serositis episodes. FMF is caused by mutations in the MEFV gene which encodes the pyrin protein, an IL-1β mediated inflammation regulator. Recent findings have identified a plethora of molecules and pathways involved in the regulation of inflammation and innate immunity, hence increasing our understanding of the etiology and inflammatory nature of FMF. Cytokines, in particular, have been found to play a key role in the pathogenesis and treatment of the disease. Indeed, various studies associated cytokines’ genetic variations and expression with susceptibility to and severity of the disease, which was further supported by the positive response of patients, both children and adults, to targeted cytokine blocking therapies. These studies highlighted the potential use of cytokines as biomarkers and target in resistant/intolerant patients and contributed to improving the early detection of FMF in children, thus enhancing their quality of life and providing alternative treatment for severe cases. The aim of this review is to provide the latest updates on the pivotal role of cytokines in FMF and to discuss the efficacy and safety of anti-cytokine biologics by primarily focusing on pediatric FMF cases.
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- 2024
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79. Analyzing efficiency of a lentiviral shRNA knockdown system in human enteroids using western blot and flow cytometry
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Adam P. Wilson, Karni S. Moshal, Addison P. Franca, Sasirekha Ramani, Randle Gallucci, Hala Chaaban, and Kathryn Y. Burge
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cell culture ,flow cytometry ,gene expression ,protein expression and purification ,cell differentiation ,organoids ,Science (General) ,Q1-390 - Abstract
Summary: Enteroids are in vitro models to study gastrointestinal pathologies and test personalized therapeutics; however, the inherent complexity of enteroids often renders standard gene editing approaches ineffective. Here, we introduce a refined lentiviral transfection protocol, ensuring sufficient lentiviral engagement with enteroids while considering spatiotemporal growth variability throughout the extracellular matrix. Additionally, we highlight a selection process for transduced cells, introduce a protocol to accurately measure transduction efficiency, and explore methodologies to gauge effects of gene knockdown on biological processes. : Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics.
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- 2024
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80. Engineered phalangeal grafts for children with symbrachydactyly: A proof of concept
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Romain Schaller, Adrien Moya, Gangyu Zhang, Mansoor Chaaban, Robert Paillaud, Ewelina M Bartoszek, Dirk J Schaefer, Ivan Martin, Alexandre Kaempfen, and Arnaud Scherberich
- Subjects
Biochemistry ,QD415-436 - Abstract
Tissue engineering approaches hold great promise in the field of regenerative medicine, especially in the context of pediatric applications, where ideal grafts need to restore the function of the targeted tissue and consider growth. In the present study, we aimed to develop a protocol to engineer autologous phalangeal grafts of relevant size for children suffering from symbrachydactyly. This condition results in hands with short fingers and missing bones. A previously-described, developmentally-inspired strategy based on endochondral ossification (ECO)—the main pathway leading to bone and bone marrow development—and adipose derived-stromal cells (ASCs) as the source of chondroprogenitor was used. First, we demonstrated that pediatric ASCs associated with collagen sponges can generate hypertrophic cartilage tissues (HCTs) in vitro that remodel into bone tissue in vivo via ECO. Second, we developed and optimized an in vitro protocol to generate HCTs in the shape of small phalangeal bones (108–390 mm 3 ) using freshly isolated adult cells from the stromal vascular fraction (SVF) of adipose tissue, associated with two commercially available large collagen scaffolds (Zimmer Plug ® and Optimaix 3D ® ). We showed that after 12 weeks of in vivo implantation in an immunocompromised mouse model such upscaled grafts remodeled into bone organs (including bone marrow tissues) retaining the defined shape and size. Finally, we replicated similar outcome (albeit with a slight reduction in cartilage and bone formation) by using minimally expanded pediatric ASCs (3 × 10 6 cells per grafts) in the same in vitro and in vivo settings, thereby validating the compatibility of our pediatric phalanx engineering strategy with a clinically relevant scenario. Taken together, these results represent a proof of concept of an autologous approach to generate osteogenic phalangeal grafts of pertinent clinical size, using ASCs in children born with symbrachydactyly, despite a limited amount of tissue available from pediatric patients.
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- 2024
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81. Performance Analysis under IRS-User Association for Distributed IRSs Assisted MISO Systems
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Alwazani, Hibatallah, Nadeem, Qurrat-Ul-Ain, and Chaaban, Anas
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Computer Science - Information Theory ,Electrical Engineering and Systems Science - Signal Processing - Abstract
Distributed intelligent reflecting surfaces (IRSs) deployed in multi-user wireless communication systems promise improved system performance. However, the signal-to-interference-plus-noise ratio (SINR) analysis and IRSs optimization in such a system become challenging, due to the large number of involved parameters. The system optimization can be simplified if users are associated with IRSs, which in turn focus on serving the associated users. We provide a practical theoretical framework for the average SINR analysis of a distributed IRSs-assisted multi-user MISO system, where IRSs are optimized to serve their associated users. In particular, we derive the average SINR expression under maximum ratio transmission (MRT) precoding at the BS and optimized reflect beamforming configurations at the IRSs. A successive refinement (SR) method is then outlined to optimize the IRS-user association parameters for the formulated max-min SINR problem which motivates user-fairness. Simulations validate the average SINR analysis while confirming the superiority of a distributed IRSs system over a centralized IRS system as well as the gains with optimized IRS-user association as compared to random association.
- Published
- 2021
82. Factors Influencing Discipline-Specific Facilitators' Roles in a Multi-Tiered Professional Learning Programme in Higher Education
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Al-Thani, Hessa, Chaaban, Youmen, and Du, Xiangyun
- Abstract
This study investigated the roles of eleven discipline-specific facilitators in a multi-tiered professional learning programme implemented in a higher education context. The study also examined the factors supporting and hindering their emerging roles, as they facilitated professional learning opportunities to other faculty in their colleges, while also being supported by programme coordinators. Using a phenomenological approach, data were generated from multiple qualitative sources, mainly portfolio entries and interviews conducted with the eleven facilitators at the end of Phase 1 and Phase 2 of the programme. Data analysis revealed the emerging facilitation roles, as well as the intricacies of the factors that were either supports or constraints to the different facilitators. Implications for the role that facilitation played in transforming teaching and learning in a centralised context are discussed. Specifically, this study delineated the need for both bottom-up approaches supported by top-down structures, which can enhance teaching and learning pedagogies and practices. This mix of bottom-up agency and top-down authority was shown to better support discipline-specific facilitators and faculty participants alike.
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- 2023
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83. An Exploration of Sources Fostering First-Year Engineering Students' Academic Well-Being in a PBL Environment
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Chen, Juebei, Du, Xiangyun, Chaaban, Youmen, Velmurugan, Giajenthiran, Lyngdorf, Niels Erik Ruan, Norgaard, Bente, Routhe, Henrik Worm, Hansen, Soren, Guerra, Aida, and Bertel, Lykke Brogaard
- Abstract
Contribution: This article contributes to the literature surrounding first-year engineering students' academic well-being by proposing a conceptual framework guiding an understanding of supportive sources that foster students' academic well-being. A survey was designed and tested accordingly, and four factors that contribute to students' academic well-being were identified to inspire the improvement of a future course and curriculum design. Background: Prior research has pointed out that students' academic well-being has a significant impact on their persistence in their current study, learning experience, academic achievement, and competence development. However, limited studies have explored first-year engineering students' academic well-being and supportive factors in the field of engineering higher education. To support engineering students to become agentic professionals, it is meaningful to pay close attention to their academic well-being and help them to become purposeful learners at an early stage of their professional development. Research Question: (1) How can an instrument be developed and validated to characterize the sources of students' academic well-being in a project-based learning approaches (PBL) context? (2) What sources could foster students' academic well-being in a PBL context? Are there significant differences in age, gender, and discipline as a function of sources of academic well-being? Methodology: With the guidance of the conceptual framework with the domains of internal and external sources, a survey was designed based on a literature review and conducted in a PBL environment. The survey's content validity, construct validity, and reliability were tested using expert review, a pilot study, exploratory factor analysis (EFA), and Cronbach's alpha. Findings: Supportive sources fostering students' academic well-being were reported in the factors of personal values, agentic action, interactions within the learning environment, and external support. Comparisons between gender, age, and discipline verified the different impacts of the four factors on fostering academic well-being.
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- 2023
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84. The Role Identities of Discipline-Specific Facilitators in a Multi-Tiered Professional Development Program in Higher Education
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Youmen Chaaban, Hessa Al-Thani, and Xiangyun Du
- Abstract
The study explored the emerging role identities of eleven faculty who served as discipline-specific facilitators in a multi-tiered PD program, as well as the affordances and constraints which contributed to the (mis)alignment between the role identity of facilitator and their other roles as faculty. Taking the collective as the unit-of-analysis, we showed that variations occurred in the salience of facilitators' self-perceptions, beliefs, goals, and action possibilities. These variations occurred within and across their multiple roles including learner, teacher, researcher, middle leader, and peer roles, and were triggered mainly by the (1) in/compatibility of facilitators' pedagogical beliefs with PD goals and activities, (2) un/confidence in the facilitator role, and (3) absence/presence of institutional support. We suggest that the PD program provides a useful model for professional learning in Higher Education contexts, and that facilitators' role identities are important tools worthy of further support and exploration.
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- 2023
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85. An Integrated Systems Model for Understanding Experiences of Academic Leadership Development in Qatar
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Alan Floyd, Saba Mansoor Qadhi, Hessa Al-Thani, Youmen Chaaban, and Xiangyun Du
- Abstract
While leadership development is acknowledged as essential for institutional growth in the higher education sector, it remains poorly understood and under researched both empirically and theoretically. Although knowledge in this area is growing in western contexts, there is little published data from the Arabic speaking world. This article addresses this gap by reporting on a Qatar National Research Fund (QNRF) funded research project which aimed to explore academic middle leaders' experiences of leadership and leadership development in Qatar. Drawing on semi structured interviews with 17 academic middle leaders, an integrated systems model for understanding leadership development in Qatar is proposed, based on three inter-related systems: intrapersonal, relational, and institutional. This model has clear implications for future leadership development policy and practice, which it is argued needs to acknowledge the nuanced and complex leadership behaviours and interactions that are required to run academic departments successfully.
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- 2023
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86. University Teachers' Professional Agency for Learning and Leading Sustainable Change
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Youmen Chaaban, Hessa Al-Thani, and Xiangyun Du
- Abstract
Using social constructivist theories of adult learning and complexity thinking perspectives, a long-term, multi-tiered professional development (PD) programme was designed, implemented and evaluated at Qatar University. This qualitative study explored the systems of influence on 24 university teachers' professional agency for learning and leading sustainable change throughout their participation in the programme. Within the context of educational change, university teachers' professional agency refers to their ability to exercise control, take stances, make choices and exert influence in ways that impact their learning and leading sustainable change. Using multiple sources of data, participants reported supports and constraints to their professional agency within multiple systems. These systems of influence included factors within the personal, PD programme, department/college, and university systems. Findings revealed variations in university teachers' willingness and capacity to examine previously held beliefs, design innovative pedagogies, and become change agents. The findings underscore the notion of emergence as an explicit characteristic of learning and leading change within and across complex systems. Future iterations of the programme, and similarly constructed programmes in higher education contexts, should consider the systems of influence on university teachers' professional agency for learning and make concerted efforts to support their ability to lead sustainable change.
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- 2023
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87. Systematic Review: Outcome Prediction in Acute Severe Ulcerative Colitis
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Julia Angkeow, Alissa Rothman, Lara Chaaban, Nicole Paul, and Joanna Melia
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Acute Severe Ulcerative Colitis ,Systematic Review ,Predictors of Outcome ,Diseases of the digestive system. Gastroenterology ,RC799-869 - Abstract
Background and Aims: Approximately 1 in 4 patients with ulcerative colitis experiences a severe exacerbation of disease requiring hospitalization, termed acute severe ulcerative colitis (ASUC). These episodes pose a major burden on patients with ulcerative colitis and early prediction of their outcomes based on clinical data is crucial to optimize therapy. Methods: A systematic review was performed using Embase and Medline for articles between 2000 and 2023. Studies obtained from the databases were uploaded on Covidence for screening by 2 independent reviewers. Quality appraisal for each study was done using the Critical Appraisals Skills Program depending on study design. Results: A total of 48 eligible studies were included in the review. The key predictors of ASUC identified in this review included clinical, endoscopic, and radiographic biomarkers, which were summarized. The main outcomes assessed in the studies were intravenous corticosteroid failure, need for rescue therapy, and need for colectomy. Score-based predictions and some novel markers were also included in the results. Conclusion: Utilization of evidence-based predictors of outcome in ASUC could serve as a powerful tool in customizing therapeutic measures and a step forward toward personalized patient care. Despite promising candidates, there remains a significant opportunity to identify and test additional clinical and laboratory-based predictors, especially early in the hospitalization and as the clinical practice and medical therapies evolve.
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- 2024
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88. Inequalities in Wellbeing in Lebanese Children and Different Refugee Subpopulations: A Multidimensional Child Deprivation Analysis
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Jamaluddine, Zeina, Safadi, Gloria, Irani, Alexandra, Salti, Nisreen, Chaaban, Jad, Abdulrahim, Sawsan, Thomas, Alban, and Ghattas, Hala
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- 2023
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89. Validation of OpenCap: A low-cost markerless motion capture system for lower-extremity kinematics during return-to-sport tasks
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Turner, Jeffrey A., Chaaban, Courtney R., and Padua, Darin A.
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- 2024
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90. Distributed Reconfigurable Intelligent Surfaces Assisted Wireless Communication: Asymptotic Analysis under Imperfect CSI
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Al-Nahhas, Bayan, Nadeem, Qurrat-Ul-Ain, and Chaaban, Anas
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Computer Science - Information Theory ,Electrical Engineering and Systems Science - Signal Processing - Abstract
This work studies the net sum-rate performance of a distributed reconfigurable intelligent surfaces (RISs)-assisted multi-user multiple-input-single-output (MISO) downlink communication system under imperfect instantaneous-channel state information (I-CSI) to implement precoding at the base station (BS) and statistical-CSI (S-CSI) to design the RISs phase-shifts. Two channel estimation (CE) protocols are considered for I-CSI acquisition: (i) a full CE protocol that estimates all direct and RISs-assisted channels over multiple training sub-phases, and (ii) a low-overhead direct estimation (DE) protocol that estimates the end-to-end channel in a single sub-phase. We derive the deterministic equivalents of signal-to-interference-plus-noise ratio (SINR) and ergodic net sum-rate under Rayleigh and Rician fading and both CE protocols, for given RISs phase-shifts, which are then optimized based on S-CSI. Simulation results reveal that the low-complexity DE protocol yields better net sum-rate than the full CE protocol when used to obtain CSI for precoding. A benchmark full I-CSI based RISs design is also outlined and shown to yield higher SINR but lower net sum-rate than the S-CSI based RISs design due to the large overhead associated with full I-CSI acquisition. Therefore the proposed DE-S-CSI based design for precoding and reflect beamforming achieves high net sum-rate with low complexity, overhead and power consumption.
- Published
- 2021
91. RIS-Aided Cell-Free Massive MIMO: Performance Analysis and Competitiveness
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Al-Nahhas, Bayan, Obeed, Mohanad, Chaaban, Anas, and Hossain, Md. Jahangir
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Computer Science - Information Theory ,Electrical Engineering and Systems Science - Signal Processing - Abstract
In this paper, we consider and study a cell-free massive MIMO (CF-mMIMO) system aided with reconfigurable intelligent surfaces (RISs), where a large number of access points (APs) cooperate to serve a smaller number of users with the help of RIS technology. We consider imperfect channel state information (CSI), where each AP uses the local channel estimates obtained from the uplink pilots and applies conjugate beamforming for downlink data transmission. Additionally, we consider random beamforming at the RIS during both training and data transmission phases. This allows us to eliminate the need of estimating each RIS assisted link, which has been proven to be a challenging task in literature. We then derive a closed-form expression for the achievable rate and use it to evaluate the system's performance supported with numerical results. We show that the RIS provided array gain improves the system's coverage, and provides nearly a 2-fold increase in the minimum rate and a 1.5-fold increase in the per-user throughput. We also use the results to provide preliminary insights on the number of RISs that need to be used to replace an AP, while achieving similar performance as a typical CF-mMIMO system with dense AP deployment.
- Published
- 2021
92. Joint Beamforming Design for Multiuser MISO Downlink Aided by a Reconfigurable Intelligent Surface and a Relay
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Obeed, Mohanad and Chaaban, Anas
- Subjects
Computer Science - Information Theory - Abstract
Reconfigurable intelligent surfaces (RIS) have drawn considerable attention recently due to their controllable scattering elements that are able to direct electromagnetic waves into desirable directions. Although RISs share some similarities with relays, the two have fundamental differences impacting their performance. To harness the benefits of both relaying and RISs, a multi-user communication system is proposed in this paper wherein a relay and an RIS cooperate to improve performance in terms of energy efficiency. Using singular value decomposition (SVD), semidefinite programming (SDP), and function approximations, we propose different solutions for optimizing the beamforming matrices at the base-station (BS), the relay, and the phase shifts at the RIS to minimize the total transmit power subject to quality-of-service (QoS) constraints. The problem is solved in different cases when the relay operates in half-duplex and full-duplex modes and when the reflecting elements have continuous and discrete phase shifts. Simulation results are provided to compare the performance of the system with and without the RIS or the relay in both full-duplex and half-duplex modes, under different optimization solutions. Generally, the results show that the system with full-duplex relay and RIS cooperation outperforms all the other scenarios, and the contribution of full-duplex relay is higher than that of the RIS. However, an RIS performs better than a half-duplex relay when the required QoS is high. The results also show that increasing the number of RIS reflecting elements improves performance better in the presence of a relay than in its absence., Comment: arXiv admin note: substantial text overlap with arXiv:2104.02849
- Published
- 2021
93. Distributed Resource Management in Downlink Cache-Enabled Multi-Cloud Radio Access Networks
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Reifert, Robert-Jeron, Ahmad, Alaa Alameer, Dahrouj, Hayssam, Chaaban, Anas, Sezgin, Aydin, Al-Naffouri, Tareq Y., and Alouini, Mohamed-Slim
- Subjects
Computer Science - Information Theory - Abstract
In light of the premises of beyond fifth generation (B5G) networks, the need for better exploiting the capabilities of cloud-enabled networks arises, so as to cope with the large-scale interference resulting from the massive increase of data-hungry systems. A compound of several clouds, jointly managing inter-cloud and intra-cloud interference, constitutes a practical solution to account for the requirements of B5G networks. This paper considers a multi-cloud radio access network model (MC-RAN), where each cloud is connected to a distinct set of base stations (BSs) via limited capacity fronthaul links. The BSs are equipped with local cache storage and baseband processing capabilities, as a means to alleviate the fronthaul congestion problem. The paper then investigates the problem of jointly assigning users to clouds and determining their beamforming vectors so as to maximize the network-wide energy efficiency (EE) subject to fronthaul capacity and transmit power constraints. This paper solves such a mixed discrete-continuous, non-convex optimization problem using fractional programming (FP) and successive inner-convex approximation (SICA) techniques to deal with the non-convexity of the continuous part of the problem, and $l_0$-norm approximation to account for the binary association part. A highlight of the proposed algorithm is its capability of being implemented in a distributed fashion across the network's multiple clouds through a reasonable amount of information exchange. The numerical simulations illustrate the pronounced role the proposed algorithm plays in alleviating the interference of large-scale MC-RANs, especially in dense networks., Comment: 36 pages, 11 figures; rewritten most sections, typos corrected, references added, added new subsection to results and numerical simulations. A version of this work is due to be submitted to the IEEE for possible publication
- Published
- 2021
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94. Relay-Reconfigurable Intelligent Surface Cooperation for Energy-Efficient Multiuser Systems
- Author
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Obeed, Mohanad and Chaaban, Anas
- Subjects
Computer Science - Information Theory - Abstract
Reconfigurable intelligent surfaces (RIS) have drawn considerable attention recently due to their controllable scattering elements that are able to direct electromagnetic waves into desirable directions. Although RISs share some similarities with relays, the two have fundamental differences impacting their performance. To harness the benefits of both relaying and RISs, a multi-user communication system is proposed in this paper wherein a relay and an RIS cooperate to improve performance in terms of energy efficiency. To utilize the RIS efficiently, the discrete phase shifts of the RIS elements are optimized along with the beamforming matrices at the transmitter and the relay, targeting the minimization of the total transmit power subject to a quality-of-service (QoS) constraint. Then, two suboptimal efficient solutions are proposed for the resulting discrete and non-convex problem, one based on singular value decomposition (SVD) and uplink-downlink duality and the other is based on SVD combined with zero-forcing. Simulations show that the proposed solutions outperform a system with either a relay or an RIS only, especially when both are closer to the users than to the base-station.
- Published
- 2021
95. Intelligent Reflecting Surface Enabled Random Rotations Scheme for the MISO Broadcast Channel
- Author
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Nadeem, Qurrat-Ul-Ain, Zappone, Alessio, and Chaaban, Anas
- Subjects
Computer Science - Information Theory ,Electrical Engineering and Systems Science - Signal Processing - Abstract
The current literature on intelligent reflecting surface (IRS) focuses on optimizing the IRS phase shifts to yield coherent beamforming gains, under the assumption of perfect channel state information (CSI) of individual IRS-assisted links, which is highly impractical. This work, instead, considers the random rotations scheme at the IRS in which the reflecting elements only employ random phase rotations without requiring any CSI. The only CSI then needed is at the base station (BS) of the overall channel to implement the beamforming transmission scheme. Under this framework, we derive the sum-rate scaling laws in the large number of users regime for the IRS-assisted multiple-input single-output (MISO) broadcast channel, with optimal dirty paper coding (DPC) scheme and the lower-complexity random beamforming (RBF) and deterministic beamforming (DBF) schemes at the BS. The random rotations scheme increases the sum-rate by exploiting multi-user diversity, but also compromises the gain to some extent due to correlation. Finally, energy efficiency maximization problems in terms of the number of BS antennas, IRS elements and transmit power are solved using the derived scaling laws. Simulation results show the proposed scheme to improve the sum-rate, with performance becoming close to that under coherent beamforming for a large number of users., Comment: Accepted in IEEE Transactions on Wireless Communications
- Published
- 2021
96. The Impact of Storytelling about an Innovative and Sustainable Organic Beef Production System on Product Acceptance, Preference, and Satisfaction
- Author
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Beata Ewa Najdek, Nora Chaaban, Margrethe Therkildsen, and Barbara Vad Andersen
- Subjects
sustainability ,organic red meat production ,storytelling ,consumer acceptance ,consumer satisfaction ,consumer preference ,Chemical technology ,TP1-1185 - Abstract
Food labels and storytelling are marketing tools used by the food industry to highlight and communicate important product characteristics to consumers. By using these tools, food companies can influence consumers’ attitudes toward the product and potentially the likelihood of purchase. In the present study, we investigated how storytelling about an innovative and sustainable organic beef production system influenced participants’ preference and acceptance of a veal steak product and, further, if some information characteristics were more important than others for consumer satisfaction. Without being aware that the samples were identical, participants (n = 224) tasted two veal steak samples: one steak sample was presented with information about the production system, and the other without information. Results showed that when the steak sample was presented with product information, compared to without information, it received significantly higher hedonic ratings (overall liking, liking of flavor, and liking of texture). This was likewise reflected in a greater preference for the steak sample when presented with product information. Furthermore, product information was found to positively impact the participants’ satisfaction with the steak sample regardless of their preference. Overall, our results suggest that the use of storytelling about the innovative and sustainable product system for veal steaks can positively influence consumers’ attitudes toward the product.
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- 2024
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97. Structural Response of Post-Tensioned Slabs Reinforced with Forta-Ferro and Conventional Shear Reinforcement under Impact Load
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Sandy Chaaban, Yehya Temsah, Ali Jahami, and Mohamad Darwiche
- Subjects
post-tensioned concrete ,Forta-Ferro fiber reinforcement ,shear reinforcement ,impact load resistance ,structural performance ,fiber-reinforced concrete ,Chemicals: Manufacture, use, etc. ,TP200-248 ,Textile bleaching, dyeing, printing, etc. ,TP890-933 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 - Abstract
Several researchers have studied how impact loads from impact hazards affect reinforced concrete (RC) slabs. There is relatively little research on impact loading effects on pre-stressed structures. The usage of fibers in structural elements intrigued researchers. In this paper, impact-loaded post-tensioned (PT) slabs with and without Forta-Ferro fibers were compared to post-tensioned slabs with plain concrete and conventional shear reinforcement. Forta-Ferro is a lightweight, low-cost fiber, and hence its effects on slab structural response under impact load deserve to be explored. Post-tensioned slabs’ impact resistance and energy absorption were tested using real-world situations of rapid and severe loads. Four identical 3.3 by 1.5 m concrete slabs were utilized in the experiment. The experiment involved dropping a 600 kg iron ball from 8 m onto each slab’s center of gravity. The slabs’ responses were investigated. The four slab configurations were tested for displacement, energy absorption, and cracking. Forta-Ferro fiber reinforcement is understudied, making this study significant. The study’s findings may help us comprehend fiber-reinforced concrete PT slabs’ impact resistance and structural performance. Engineers and designers of impact-prone buildings like slabs and bridges will benefit from the findings. The study also suggests adding Forta-Ferro fibers to post-tensioned slabs to improve durability and resilience against unanticipated impact hazards.
- Published
- 2024
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98. Hyaluronic Acid 35 kDa Protects against a Hyperosmotic, Formula Feeding Model of Necrotizing Enterocolitis
- Author
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Burge, Kathryn, Eckert, Jeffrey, Wilson, Adam, Trammell, MaJoi, Lueschow, Shiloh R, McElroy, Steven J, Dyer, David, and Chaaban, Hala
- Subjects
Paediatrics ,Biomedical and Clinical Sciences ,Pediatric ,Infant Mortality ,Preterm ,Low Birth Weight and Health of the Newborn ,Nutrition ,Digestive Diseases ,Prevention ,Rare Diseases ,Perinatal Period - Conditions Originating in Perinatal Period ,2.1 Biological and endogenous factors ,Aetiology ,Oral and gastrointestinal ,Good Health and Well Being ,Animals ,Animals ,Newborn ,Disease Models ,Animal ,Dysbiosis ,Enterocolitis ,Necrotizing ,Humans ,Hyaluronic Acid ,Infant ,Newborn ,Infant ,Newborn ,Diseases ,Infant ,Premature ,Inflammation ,Mice ,necrotizing enterocolitis ,hyaluronic acid ,prematurity ,formula feeding ,human milk ,osmolality ,microbiome ,Food Sciences ,Nutrition and Dietetics ,Clinical sciences ,Nutrition and dietetics ,Public health - Abstract
Necrotizing enterocolitis (NEC), an inflammatory disease of the intestine, is a common gastrointestinal emergency among preterm infants. Intestinal barrier dysfunction, hyperactivation of the premature immune system, and dysbiosis are thought to play major roles in the disease. Human milk (HM) is protective, but the mechanisms underpinning formula feeding as a risk factor in the development of NEC are incompletely understood. Hyaluronic acid 35 kDa (HA35), a bioactive glycosaminoglycan of HM, accelerates intestinal development in murine pups during homeostasis. In addition, HA35 prevents inflammation-induced tissue damage in pups subjected to murine NEC, incorporating Paneth cell dysfunction and dysbiosis. We hypothesized HA35 treatment would reduce histological injury and mortality in a secondary mouse model of NEC incorporating formula feeding. NEC-like injury was induced in 14-day mice by dithizone-induced disruption of Paneth cells and oral gavage of rodent milk substitute. Mortality and histological injury, serum and tissue cytokine levels, stool bacterial sequencing, and bulk RNA-Seq comparisons were analyzed. HA35 significantly reduced the severity of illness in this model, with a trend toward reduced mortality, while RNA-Seq analysis demonstrated HA35 upregulated genes associated with goblet cell function and innate immunity. Activation of these critical protective and reparative mechanisms of the small intestine likely play a role in the reduced pathology and enhanced survival trends of HA-treated pups subjected to intestinal inflammation in this secondary model of NEC, providing potentially interesting translational targets for the human preterm disease.
- Published
- 2022
99. Early Antibiotic Exposure Alters Intestinal Development and Increases Susceptibility to Necrotizing Enterocolitis: A Mechanistic Study
- Author
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Chaaban, Hala, Patel, Maulin M, Burge, Kathryn, Eckert, Jeffrey V, Lupu, Cristina, Keshari, Ravi S, Silasi, Robert, Regmi, Girija, Trammell, MaJoi, Dyer, David, McElroy, Steven J, and Lupu, Florea
- Subjects
Paediatrics ,Biomedical and Clinical Sciences ,Clinical Research ,Pediatric ,Rare Diseases ,Infectious Diseases ,Preterm ,Low Birth Weight and Health of the Newborn ,Perinatal Period - Conditions Originating in Perinatal Period ,Infant Mortality ,Digestive Diseases ,6.1 Pharmaceuticals ,Evaluation of treatments and therapeutic interventions ,Infection ,Oral and gastrointestinal ,Good Health and Well Being ,necrotizing enterocolitis ,intestinal permeability ,intestinal development ,antibiotics ,preterm infant ,microbiome ,Microbiology ,Medical microbiology - Abstract
Increasing evidence suggests that prolonged antibiotic therapy in preterm infants is associated with increased mortality and morbidities, such as necrotizing enterocolitis (NEC), a devastating gastrointestinal pathology characterized by intestinal inflammation and necrosis. While a clinical correlation exists between antibiotic use and the development of NEC, the potential causality of antibiotics in NEC development has not yet been demonstrated. Here, we tested the effects of systemic standard-of-care antibiotic therapy for ten days on intestinal development in neonatal mice. Systemic antibiotic treatment impaired the intestinal development by reducing intestinal cell proliferation, villi height, crypt depth, and goblet and Paneth cell numbers. Oral bacterial challenge in pups who received antibiotics resulted in NEC-like intestinal injury in more than half the pups, likely due to a reduction in mucous-producing cells affecting microbial-epithelial interactions. These data support a novel mechanism that could explain why preterm infants exposed to prolonged antibiotics after birth have a higher incidence of NEC and other gastrointestinal disorders.
- Published
- 2022
100. Kefir mitigates renal damage caused by zearalenone in female wistar rats by reducing oxidative stress
- Author
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Ben Taheur, Fadia, Mansour, Chalbia, Skhiri, Sihem Safta, Chaaban, Habib, Jridi, Mourad, Fakhfakh, Nahed, and Zouari, Nacim
- Published
- 2024
- Full Text
- View/download PDF
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