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Letteratura scientifica selezionata sul tema "Artificial heart"

Autore: Grafiati

Pubblicato: 4 giugno 2021

Ultima modifica: 31 luglio 2024

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Articoli di riviste sul tema "Artificial heart"

Gilbert, Alan, e Peter Gizzi. "Artificial Heart". Chicago Review 44, n. 3/4 (1998): 197. http://dx.doi.org/10.2307/25304332.

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Moyer, Michael. "Artificial Heart". Scientific American 301, n. 3 (settembre 2009): 75. http://dx.doi.org/10.1038/scientificamerican0909-75b.

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Harasaki, H., e L. Golding. "Artificial heart". Current Opinion in Cardiology 3, n. 5 (settembre 1988): 770–75. http://dx.doi.org/10.1097/00001573-198809000-00020.

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Yuan, Yuan. "Analysis of the current status and development prospects of artificial hearts". Theoretical and Natural Science 29, n. 1 (8 gennaio 2024): 108–11. http://dx.doi.org/10.54254/2753-8818/29/20240755.

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Abstract (sommario):

Confronted with the rapid need for transplantable hearts, patients who need a heart transplant cannot receive the suitable configuration. Thus contributes to the development of artificial hearts, which can be created to substitute the old, the ill heart without waiting for transplantable hearts. Nowadays, this paper shows the public the artificial hearts. Through the extensive literature, it is clear that the development of artificial hearts. Dating back to the fifties of the last century, scientists began studying artificial hearts. Till now, China has created four generations of artificial hearts. They became more and more strong. The importance of the heart goes without saying, however, every year there are more and more heart failure patients. Paying more attention to the artificial hearts helps reduce the death rate of heart failures. Actually, although the patients can get the heart donors, they may not tolerate rejection. So research into artificial hearts more suitable for patients is imminent. This paper mainly introduces the fourth-generation artificial hearts (in fact, it is an improved version of the third generation), the magnetic levitation artificial heart attracts much more attention, and its composition and function have been greatly improved, reducing the difficulty of surgery. It is hoped that people can know much more about artificial hearts, and prospects for better methods to make better artificial hearts, and promote heart transplantations.

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Shankar, Mr A. Ravi, Dr S. Kishore Reddy e Dr Sultan Feisso. "Prototype of Total Artificial Heart System". International Journal of Trend in Scientific Research and Development Volume-1, Issue-6 (31 ottobre 2017): 850–55. http://dx.doi.org/10.31142/ijtsrd4693.

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Frankel, William C., e Tom C. Nguyen. "Artificial Heart Valves". JAMA 325, n. 24 (22 giugno 2021): 2512. http://dx.doi.org/10.1001/jama.2020.19936.

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Dunning, J. "Artificial heart transplants". British Medical Bulletin 53, n. 4 (1 gennaio 1997): 706–18. http://dx.doi.org/10.1093/oxfordjournals.bmb.a011642.

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White, Boyd. "The Artificial Heart". Iowa Review 21, n. 1 (gennaio 1991): 110–11. http://dx.doi.org/10.17077/0021-065x.3974.

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Grunkemeier, G. L., e S. H. Rahimtoola. "Artificial Heart Valves". Annual Review of Medicine 41, n. 1 (febbraio 1990): 251–63. http://dx.doi.org/10.1146/annurev.me.41.020190.001343.

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&NA;. "ARTIFICIAL HEART, TOTAL". ASAIO Journal 42, n. 2 (aprile 1996): 4–9. http://dx.doi.org/10.1097/00002480-199642020-00003.

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Tesi sul tema "Artificial heart"

Nishta, B. V. "Artificial heart". Thesis, Сумський державний університет, 2014. http://essuir.sumdu.edu.ua/handle/123456789/35027.

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Abstract (sommario):

An artificial heart is a device that replaces the heart. Artificial hearts are typically used to bridge the time to heart transplantation, or to permanently replace the heart in case heart transplantation is impossible. Although other similar inventions preceded it are going back to the late 1940s, the first artificial heart to be successfully implanted in a human was the Jarvik-7, designed by Robert Jarvik and implemented in 1982. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35027

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Westaby, Stephen. "Towards a realistic artificial heart". Thesis, University of Strathclyde, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248952.

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MICCIOLO, MATTEO. "ASSISTENZE MECCANICHE AL CIRCOLO: PADUA HEART PROJECT A TOTAL ARTIFICIAL HEART". Doctoral thesis, Università degli studi di Padova, 2015. http://hdl.handle.net/11577/3423929.

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Background While the prevalence of heart failure (HF) in Europe and the USA has increased constantly in the last decades up to 12 million patients, we are still missing available, effective therapeutic options for advanced HF refractory to medical management, accounting for 5% of the total HF patient population. In fact, cardiac transplantation remains the primary option for a select group of end-stage HF patients but it is strongly limited due to the shortage of donor organs. The research in the field of mechanical devices to support or substitute the pumping function of failing heart is therefore strongly pursued. Since the end of the 90’s, thanks to the improved performance and safety of left ventricular assist devices (LVADs), their clinical use has increased both as a bridge to cardiac transplantation (BTT) and as a lifelong therapy. In case of end-stage biventricular failure or candidates with restrictive or infiltrative cardiomyopathies with ventricular cavities too small to accommodate apical inflow cannulae, LVADs are not a viable option: bi-ventricular assist devices (BiVAD) or total artificial hearts (TAH) are needed. To date, in INTERMACS records, only less than 5% of implanted mechanical circulatory support devices are BiVAD or TAH; however these figures do not reflect the real need for total replacement of heart function due to the limitations of available TAH (SynCardia). State of the Art The only clinically available TAH to date is the pneumatically driven SynCardia, that was FDA approved for BTT in 2004. It requires no surgical pocket, can provide up to 10 L/min flow with physiological control through both pulsatile pumping chambers. However, the TAH requires adequate mediastinal space to accommodate the dual-chambered pump. Its last generation portable pneumatic controller allows patients to be discharged from the hospital, although patients’ quality of life is limited by noise and weight of the drive unit (6 kg) that they need to carry. Device malfunction, along with bleeding, stroke, and infection, remain concerns with this technology. New TAHs research and development Several new TAH projects were started and stopped at different stage of development such as Abiomed Abiocor, Cliveland Clinic Foundation Magscrew, Aachen AME ReinHeart, only to quote few recent ones. Either technical issues prevented projects to get regulatory approval for clinical use or lack of research funding did not allow project completion. At the time being, Carmat TAH (Carmat SA) is undergoing pre-clinical tests. It is an implantable, electro-hydraulically driven, pulsatile flow device with four bioprosthetic valves. The stroke volume (30–65 ml) and the beat rate (35–150 b/min) of the prosthesis adapt automatically in response to changes in preload and the resulting pulsatile blood flow ranges from 2 to 9 l/min. Its blood-pumping surfaces consist of processed bioprosthetic pericardial tissue, potentially allowing for the reduction of anti-coagulation. Despite such innovative aspect, the implantable pump is huge and needs sternum-to-vertebral column minimum distance of 13 cm to be implanted. Conclusion: Padua Heart Project In order to provide an innovative solution in the field of MCS, Padua Heart Project (PHP) pursues the design of a small size, electromechanically driven TAH, that can deliver pulsatile blood flow to meet physiological need. While all of the above mentioned TAH projects are based on rotary motors with a conversion gear, thus consisting of many wear-prone parts, limiting their durability, PHP is based on a linear motor having only one moving component. Due to its original design and control mode, the size of the linear motor can be only slightly larger than the blood sacs. Furthermore, its inner lining can be coated by processed pericardial tissue. As a proof of concept, a first linear drive prototype was developed and set up. The movable part of the linear motor consists of a flat magnet including two valvular prostheses. Its linear movement back and forward within the driving coil, allows compression and relaxation of a flexible blood sac and its filling and emptying through the valves. The prototype has been tested in a simple mock loop to deliver flow varying between 4.5 and 7.5 L/min with 120 mmHg of afterload. Further tests are under way to optimize blood sac shape and control mode at different sets of preload and afterload conditions.
Studio dello stato dell’arte del cuore artificiale totale (TAH) nella pratica clinica: la ricerca bibliografica è stata orientata all’analisi delle più recenti esperienze cliniche con TAH per individuarne limiti e punti di forza. L’obiettivo di tale ricerca documentale era quello di dedurre le specifiche per un nuovo TAH, in grado di soddisfare le esigenze terapeutiche ancora parzialmente o totalmente irrisolte dai sistemi attualmente disponibili: • CARATTERISTICHE DI PESO E INGOMBRO IDEALI: diametro <90 mm, lunghezza < 100 mm; peso < 800 gr (peso del cuore naturale 300- 400 gr), per poter essere impiantato anche in pazienti di piccola BSA • ATTUATORE impiantabile, elettromeccanico, efficiente, silenzioso, in grado di produrre un flusso medio di circa 6 L/min contro una pressione media di circa 100 mmHg, con capacità di sostenere sovraccarichi e picchi di flusso, con bassa dissipazione di calore verso il sangue e i tessuti • DISEGNO DELLE CAMERE VENTRICOLARI E DELLE VALVOLE rispetto al flusso ematico tale da minimizzare l’emolisi e le zone di stagnazione del flusso e il conseguente pericolo di formazione di trombi • MATERIALI USATI BIO ED EMOCOMPATIBILI: plastica, metallo, materiale biologico (PERICARDIO DECELLULARIZZATO), con caratteristiche di non tossicità, non carcinogenicità, stabilità chimica e resistenza meccanica, sterilizzabilità • INTERFACCIA DEL TAH con il circolo (atri, arterie) rispettosa dell’anatomia e con agevoli meccanismi di aggancio • DURATA DISPOSITIVO : circa 5 anni (per un sistema pulsatile, ciò corrisponde ad un numero di cicli variabile tra 225 e 350 Milioni, a seconda che lo Stroke Volume vari tra 70 e 45 ml), per poter offrire un supporto di lungo termine Studio di nuovi modelli di TAH ancora in corso di sviluppo e ricerca brevettuale su TAH innovativi: attraverso tale ricerca sono stati individuati gli spunti più interessanti tra le tecnologie in divenire ed è stato definito come orientare il progetto del TAH di Padova. In particolare, si è optato per un sistema con pompe volumetriche, a camere flessibili valvolate, azionate da motori elettrici lineari (quindi, con meno trasduzioni) di piccole dimensioni. L’attuazione prevede un movimento push-pull del piano delle valvole, che realizza contemporaneamente il riempimento e l’eiezione dalle camere ventricolari. Questo consente, a parità di ingombro, l’aumento della portata o, viceversa, a parità di portata una considerevole riduzione di volume della pompa. Sono stati disegnate diverse possibili configurazioni della pompa push-pull e infine viene scelta soluzione con movimento dei piani valvolari, interposti tra sacco ventricolare e “atri”, disposti a “U”,con frequenza minima 60 b/min, SV 80 ml (40ml +40ml). Primi test su banco: il sistema push-pull con uno stroke volume complessivo di 80 ml ottenuto attraverso 2 eiezioni successive di 40 ml ciascuna, con frequenza di salita/discesa del motore lineare di 60b/min (1Hz) riesce a pompare 4,8 L/min contro un afterload di 120 mmHg Aumentando la frequenza a 92b/min, il sistema riesce a erogare una portata di 7.2 L/min contro lo stesso postcarico Emerge l’originalità progettuale del disegno in cui le valvole si comportano sia da organi di intercettazione sia da elementi di spinta della massa fluida. Prove su banco di confronto Drive Units di dispositive in uso clinico (Cardiowest Companion vs Freedom): sono state eseguite prove su banco di unità di controllo differenti impiegate sullo stesso modello di TAH (Cardiowest) allo scopo di individuare le variabili di controllo salienti su cui basare il sistema di attuazione del nuovo TAH. Lo spunto è stato fornito da un reale “clinical dilemma”: il paziente 1Z, a cui era stato impiantato il CardioWest nel 2007, ha iniziato a manifestare problemi di dispnea con edema polmonare, nonostante un flusso di 5 L/min, appena è passato dal sistema di attuazione Companion al più recente Freedom. Non aveva tali sintomi coi precedenti drive units Excor e Companion; nessun altro organo presentava segnali di scompenso. Le prove su banco hanno dimostrato che la più recente drive unit (Freedom), essendo molto rigida, poiché non permette la regolazione delle pressioni di attuazione dei due ventricoli, e non avendo alcun feedback sulle pressioni di riempimento del paziente, può determinare squilibri tra circolo destro e sinistro. Appare quindi molto importante nel progetto di nuovo TAH includere la possibilità di modulazione della portata in funzione delle pressioni di riempimento. Progetto di fitting virtuale del TAH: lo studio si propone di convertire TAC del torace in un modello 3D semplice rapido e affidabile della cavità toracica. I risultati attesi consistono nella definizione ottimale degli ingombri e delle forme della protesi impiantabile del TAH che si sta progettando, incluse le interfacce con atri e grandi vasi del ricevente. Inoltre, lo strumento sarebbe disponibile per la determinazione ottimale pre-operatoria del fitting anatomico in un dato paziente di un dato sistema di supporto circolatorio impiantabile. La ricerca è stata avviata in collaborazione con l’Unità di Ricerca “3DOM” della Fondazione Bruno Kessler di Trento.

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Ranawake, Manoja, e n/a. "Development of the artificial heart for serial production". University of Canberra. Industrial Design, 1995. http://erl.canberra.edu.au./public/adt-AUC20061113.151545.

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Heart disease is the principal cause of death in most industrialised countries. In the U.S.A. for example, 2.3 million individuals suffer from chronic heart failure, with an annual increase in numbers of 17%. It is estimated that 17,000 to 35,000 of them per year will die from this disease if they are not given either a heart transplant or an artificial heart. Unfortunately, the numbers of heart donors cannot meet the demand for transplantation, and, at present, the artificial heart is a prohibitively expensive alternative. The total artificial heart (TAH) intended for the total replacement of the natural heart is still some years away from realisation. However, the ventricular assist device (VAD) which is used temporarily to maintain an ailing heart is available now, although only in restricted numbers due to difficulties in processing the biocompatible materials used during manufacture. Consequently, such devices are expensive, costing anywhere from AUS$30,000 for the pump head to AUS$200,000 for a complete system. In this study, the Australian designed $quot;Spiral Vortex$quot; VAD was used to investigate fabrication techniques for use in the eventual cost-effective manufacture of a pump head costing approximately AUS$4,000. A second VAD originally designed at the Kolff Laboratory, University of Utah, U.S.A. was also used for comparative evaluation. The hard-shell Spiral Vortex VAD is intended to be used outside the body, while the soft-shell Kolff VAD has the advantage of being implantable for long-term use. They were cast from epoxy resin and vacuum formed from polyurethane, respectively. Several units of each were fabricated, including 60 of the Kolff VAD, for use in vitro and in vivo experiments. From these experiments it was found that both the Spiral Vortex and Kolff VADs could be fabricated to quality controllable standards. The Kolff VAD was used exclusively in chronic animal experiments, and was able to sustain sheep and goats for periods of up to five weeks. Furthermore, it became evident that techniques used in fabrication of the Kolff VAD could be adopted for use in the mass production of the Spiral Vortex VAD. The two other areas investigated in this study were the prosthetic heart valves and drive systems used for an artificial heart. A high percentage of the cost of an artificial heart is accounted for by the inflow/outflow valves. The trileaflet valve used in the Kolff VAD, which mimics the natural heart valve, was fabricated using inexpensive vacuum-forming techniques. Quality control was found to be adequate, with good flow characteristics which could be maintained for several weeks in animal experiments. Both the Spiral Vortex and Kolff VADs are pulsation pumps which require a pneumatic driver unit. This driver is the single most expensive component in a VAD system, costing upwards of AUS$150,000. The theoretical efficiency of a compact hydromechanical drive unit was investigated using a test rig to simulate an original design based primarily on proprietary components. Results obtained so far indicate that the proposed driver can operate only under limited conditions as a result of its severe reduction in size. By adopting mass production techniques wherever possible in the fabrication of the VAD (pump head) and valves, and by reducing the cost and size of the driver unit, it may therefore be possible to produce a cost effective ventricular assist device system.

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Menon, Vinay. "Fuzzy logic controller for an artificial heart". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/mq32405.pdf.

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Hui, Andrew J. "Hydrogel-based artificial heart valve stent material". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0018/MQ58005.pdf.

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Alsalamah, Mashail. "Heart diseases diagnosis using artificial neural networks". Thesis, Coventry University, 2017. http://curve.coventry.ac.uk/open/items/a9564d2b-df62-4573-8888-cabdbbdcd4e0/1.

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Information technology has virtually altered every aspect of human life in the present era. The application of informatics in the health sector is rapidly gaining prominence and the benefits of this innovative paradigm are being realized across the globe. This evolution produced large number of patients’ data that can be employed by computer technologies and machine learning techniques, and turned into useful information and knowledge. This data can be used to develop expert systems to help in diagnosing some life-threating diseases such as heart diseases, with less cost, processing time and improved diagnosis accuracy. Even though, modern medicine is generating huge amount of data every day, little has been done to use this available data to solve challenges faced in the successful diagnosis of heart diseases. Highlighting the need for more research into the usage of robust data mining techniques to help health care professionals in the diagnosis of heart diseases and other debilitating disease conditions. Based on the foregoing, this thesis aims to develop a health informatics system for the classification of heart diseases using data mining techniques focusing on Radial Basis functions and emerging Neural Networks approach. The presented research involves three development stages; firstly, the development of a preliminary classification system for Coronary Artery Disease (CAD) using Radial Basis Function (RBF) neural networks. The research then deploys the deep learning approach to detect three different types of heart diseases i.e. Sleep Apnea, Arrhythmias and CAD by designing two novel classification systems; the first adopt a novel deep neural network method (with Rectified Linear unit activation) design as the second approach in this thesis and the other implements a novel multilayer kernel machine to mimic the behaviour of deep learning as the third approach. Additionally, this thesis uses a dataset obtained from patients, and employs normalization and feature extraction means to explore it in a unique way that facilitates its usage for training and validating different classification methods. This unique dataset is useful to researchers and practitioners working in heart disease treatment and diagnosis. The findings from the study reveal that the proposed models have high classification performance that is comparable, or perhaps exceed in some cases, the existing automated and manual methods of heart disease diagnosis. Besides, the proposed deep-learning models provide better performance when applied on large data sets (e.g., in the case of Sleep Apnea), with reasonable performance with smaller data sets. The proposed system for clinical diagnoses of heart diseases, contributes to the accurate detection of such disease, and could serve as an important tool in the area of clinic support system. The outcome of this study in form of implementation tool can be used by cardiologists to help them make more consistent diagnosis of heart diseases.

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Barsanti, Stephen. "Observations on the mechanical behaviour of polyurethane heart valves". Thesis, University of the West of Scotland, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265928.

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Nugent, Allen Harold Biomedical Engineering UNSW. "Fluid dynamical investigation of a ventricular assist device". Awarded by:University of New South Wales. Biomedical Engineering, 2005. http://handle.unsw.edu.au/1959.4/35035.

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The Spiral Vortex (SV) ventricular assist device (VAD) was investigated by 2-component laser Doppler anemometry (LDA) while pumping a refractive index-matched blood analogue fluid. The VAD was operated under physiological conditions corresponding to 75% assist (4 litres/minute) or weaning from assist (2 litres/minute). Data were sampled on a 5-mm grid throughout most of the interior of the blood chamber, using two orthogonal LDA configurations from which 3D velocity data were synthesised. Data were subjected to statistical analysis of quasistatic time intervals and approximation by Fourier series. The velocity vector fields were explored statically (via 2D plots) and dynamically (using 3D animations of the reduced data). Reynolds stresses were computed and visualised in 2D. Fluid pathlines were simulated and plotted in 3D. The flow was found to be dominated by an irrotational vortex that accelerated and precessed in phase with the pumping diaphragm. Two unexpected flow structures, a rising, swirling near-wall layer in diastole and a reflection of the outflow vortex upon valve closure, enhanced washing of the walls. The thickness of the boundary layer was estimated to be 2 mm. Fluid velocities were generally lower than those reported in steady-flow studies on the SV VAD, although turbulence was comparable. Under the weaning mode, the coherence of the main vortex was degraded and flow recirculation was observed distal to the inflow port; this operating mode must be regarded as an indication for anticoagulation. In both pumping modes, turbulence was elevated in association with asymmetric buckling of the pneumatically driven diaphragm. Suboptimal orientation of the tilting-disc inlet valve gave rise to augmented turbulence production and skewing of the main vortex; similar results were obtained for an axisymmetric polymer (Jellyfish) valve, despite its advantageous haemodynamics. Flow stagnation was apparent where the inflow stream impinged on the wall, opposite the inflow port. The overall design of the SV VAD appears to almost ideal, in the context of current technology. However, elimination of recirculation/stagnation zones, especially in the weaning mode, remains a priority for the ultimate optimisation of haemocompatibility. Pulsatile VADs will probably never be entirely free of flow recirculation or stagnation, and published claims to the contrary probably reflect study limitations.

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Sedighian, Pouye. "Pediatric heart sound segmentation". Thesis, California State University, Long Beach, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=1526952.

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Recent advances in technology have facilitated the prospect of automatic cardiac auscultation by using digital stethoscopes. This in turn creates the need for development of algorithms capable of automatic segmentation of the heart sound. Pediatric heart sound segmentation is a challenging task due to various factors including the significant influence of respiration on the heart sound. This project studies the application of homomorphic filtering and Hidden Markov Model for the purpose of pediatric heart sound segmentation. The efficacy of the proposed method is evaluated on a publicly available dataset and its performance is compared with those of three other existing methods. The results show that our proposed method achieves accuracy of 92.4% ±1.1% and 93.5% ±1.1% in identification of first and second heart sound components, and is superior to four other existing methods in term of accuracy or time complexity.

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Libri sul tema "Artificial heart"

Gizzi, Peter. Artificial heart. Providence, R.I: Burning Deck, 1998.

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International Symposium on Artificial Heart and Assist Device (4th 1992 Tokyo, Japan). Heart replacement: Artificial heart 4. A cura di Akutsu Tetsuzō 1922- e Koyanagi Hitoshi 1936-. Tokyo: Springer-Verlag, 1993.

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1922-, Akutsu Tetsuzō, e Koyanagi Hitoshi 1936-, a cura di. Heart replacement: Artificial heart 6. Tokyo: Springer, 1998.

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Akutsu, Tetsuzo, Hitoshi Koyanagi, Setsuo Takatani, Kazunori Kataoka, Jack G. Copeland, Stuart L. Cooper, Peer M. Portner e David B. Geselowitz, a cura di. Artificial Heart 2. Tokyo: Springer Japan, 1988. http://dx.doi.org/10.1007/978-4-431-65964-8.

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Akutsu, Tetsuzo, Hitoshi Koyanagi, James M. Anderson, Lawrence H. Cohn, Peter L. Frommer, Mitsuhiro Hachida, Kazunori Kataoka et al., a cura di. Artificial Heart 3. Tokyo: Springer Japan, 1991. http://dx.doi.org/10.1007/978-4-431-68126-7.

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Berger, Melvin. The artificial heart. New York: F. Watts, 1987.

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Yamane, Takashi. Mechanism of Artificial Heart. Tokyo: Springer Japan, 2016. http://dx.doi.org/10.1007/978-4-431-55831-6.

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United States. National Aeronautics and Space Administration., a cura di. Incomprehensive viscous flow computations for the pump components and the artificial heart. San Jose, CA: MCAT Institute, 1992.

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R, Hogness John, VanAntwerp Malin e National Heart, Lung, and Blood Institute., a cura di. The artificial heart: Prototypes, policies, and patients. Washington, D.C: National Academy Press, 1991.

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1922-, Akutsu Tetsuzō, Koyanagi Hitoshi 1936- e Japanese Research Promotion Society for Cardiovascular Diseases., a cura di. Artificial heart 2: Proceedings of the 2nd International Symposium on Artificial Heart and Assist Device, August 13-14, 1987, Tokyo, Japan. Tokyo: Springer-Verlag, 1988.

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Capitoli di libri sul tema "Artificial heart"

Mitamura, Yoshinori, Tatsuhiko Wada e Eiji Okamoto. "Feasibility of Ferromagnetic Artificial Cells for Artificial Circulation". In Heart Replacement, 482–83. Tokyo: Springer Japan, 1998. http://dx.doi.org/10.1007/978-4-431-65921-1_78.

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Han, Lu, e Wei Wang. "Total Artificial Heart". In Artificial Hearts, 95–108. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-4378-4_6.

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Copeland, Hannah, Jack G. Copeland e Richard G. Smith. "Total Artificial Heart". In Surgical Treatment for Advanced Heart Failure, 161–75. New York, NY: Springer New York, 2013. http://dx.doi.org/10.1007/978-1-4614-6919-3_13.

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Copeland, Hannah, Jennifer Berumen, Richard G. Smith e Jack G. Copeland. "The Artificial Heart". In Textbook of Organ Transplantation, 563–67. Oxford, UK: John Wiley & Sons, Ltd, 2014. http://dx.doi.org/10.1002/9781118873434.ch49.

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Stamm, Christof, e Roland Hetzer. "Total Artificial Heart". In Translational Approach to Heart Failure, 437–48. New York, NY: Springer New York, 2013. http://dx.doi.org/10.1007/978-1-4614-7345-9_17.

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Li, Yongjun, e Zhengxi Xu. "Total Artificial Heart". In Application of Biomaterials in the Treatment of Cardiovascular Diseases, 381–92. Singapore: Springer Nature Singapore, 2024. http://dx.doi.org/10.1007/978-981-19-7712-1_11.

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Shah, Keyur B., Anit K. Mankad, Daniel G. Tang e Vigneshwar Kasirajan. "The Total Artificial Heart". In Heart Failure, 691–709. London: Springer London, 2017. http://dx.doi.org/10.1007/978-1-4471-4219-5_29.

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Watson, John T. "Implantable Artificial Heart Systems". In Heart Replacement, 95–100. Tokyo: Springer Japan, 1996. http://dx.doi.org/10.1007/978-4-431-67020-9_10.

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Frazier, O. Howard, Denton A. Cooley e Hiroyuki Noda. "Completely implantable total artificial hearts: Status at the Texas Heart Institute". In Artificial Heart 3, 167–71. Tokyo: Springer Japan, 1991. http://dx.doi.org/10.1007/978-4-431-68126-7_19.

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Wei, Xufeng, e Yixin Cui. "Mechanisms of Heart Failure". In Artificial Hearts, 21–30. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-4378-4_2.

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Atti di convegni sul tema "Artificial heart"

K. Kar, Kamal, e Mridul Bharadwaj. "Artificial Heart Valve Testing Setup". In Proceedings of the International Conference on Nanotechnology for Better Living. Singapore: Research Publishing Services, 2016. http://dx.doi.org/10.3850/978-981-09-7519-7nbl16-rps-287.

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Potnuru, Akshay, Lianjun Wu e Yonas Tadesse. "Artificial heart for humanoid robot". In SPIE Smart Structures and Materials + Nondestructive Evaluation and Health Monitoring, a cura di Yoseph Bar-Cohen. SPIE, 2014. http://dx.doi.org/10.1117/12.2045289.

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Sahrani, S., N. Semangin, S. Suhaili, D. A. Awg Mat, M. S. Osman e M. Sawawi. "Electromagnetic interference on artificial heart pacemaker". In 2008 IEEE International RF and Microwave Conference (RFM). IEEE, 2008. http://dx.doi.org/10.1109/rfm.2008.4897396.

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Corrigan, J. J., M. Jeter, R. G. Smith, M. Levinson e J. G. Copeland. "FIBRINOLYTIC PEPTIDES IN ARTIFICIAL HEART RECIPIENTS". In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1642920.

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Patients who are recipients of total artificial heart (TAH) implants develop significant thromboembolic disease (TED). These events cause significant morbidity and are the leading impediments to the use of the TAH. Recently, molecular markers of activation of the hemostatic mechanism have been employed in patients with other causes of thromboembolic disease for earlier detection and for assessing management. We serially measured three fibrinolytic markers (B-beta 1-42 and B-beta 1542 fragments and crossed-1inked D-dimer, XDP) in 3 recipients of the Jarvik-7 artificial heart. The markers were assayed in plasma samples using monoclonal antibodies using ELISA methodology. Normal ranges for our lab are: B-beta 1-42, 3-14 picomoles/ml; B-beta 15-42, 15-32 picomoles/ml; and XDP 6-26 ng/ml. The TAHs were in place for 8, 9, and 252 days. Two patients died and two had strokes. Two of the 3 artificial devises had thrombosis at the time of removal. XDPs rose significantly at the time of TED (>1000 ng/ml). A significant rise in B-beta 1-42 and 15-42 was noted prior to and during the TE events. The ratio's of 1-42 to 15-42 did not change suggesting that these levels were a result of thrombin activity with secondary fibrinolytic activation and not from primary fibrinolysis. These preliminary data suggest that the use of hemostatic molecular markers may be useful for the detection of TED and in assessing control of the hypercoagulable state in TAH recipients.

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Al-Mannai, Rashid Ebrahim, Mohammed Hamad Almerekhi, Mohammed Abdulla Al-Mannai, Mishahira N, Kishor Kumar Sadasivuni, Huseyin Cagatay Yalcin, Hassen M. Ouakad, Issam Bahadur, Somaya Al-Maadeed e Asiya Albusaidi. "Artificial Intelligence in Predicting Heart Failure". In Qatar University Annual Research Forum & Exhibition. Qatar University Press, 2021. http://dx.doi.org/10.29117/quarfe.2021.0130.

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Heart Failure is a major chronic disease that is increasing day by day and a great health burden in health care systems world wide. Artificial intelligence (AI) techniques such as machine learning (ML), deep learning (DL), and cognitive computer can play a critical role in the early detection and diagnosis of Heart Failure Detection, as well as outcome prediction and prognosis evaluation. The availability of large datasets from difference sources can be leveraged to build machine learning models that can empower clinicians by providing early warnings and insightful information on the underlying conditions of the patients

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Hui, Andrew J., Anthony C. Duncan e W. K. Wan. "Hydrogel Based Artificial Heart Valve Stent". In ASME 1997 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1997. http://dx.doi.org/10.1115/imece1997-0224.

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Abstract Hydrogels have many medical applications. In this particular case, it is proposed to fabricate a heart valve stent from polyvinyl alcohol (PVA). The present heart valve stents are made of rigid materials which do not mimic the natural important mechanical properties of the aortic root such as expansibility1. We propose a new heart valve stent which can better mimic the natural mechanical properties of the aortic root.

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Dolgov, Dmitriy, e Yury Zakharov. "Mathematical modelling of artificial heart valve performance". In 2015 International Conference "Stability and Control Processes" in Memory of V.I. Zubov (SCP). IEEE, 2015. http://dx.doi.org/10.1109/scp.2015.7342202.

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"Heart Attack Prediction with Artificial Neural Network". In 2020 2nd International Symposium on the Frontiers of Biotechnology and Bioengineering (FBB 2020). Clausius Scientific Press, 2020. http://dx.doi.org/10.23977/fbb2020.010.

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Bharathi, N. Nava, Mahammad Firose Shaik, T. Poojita, T. Sravanthi, Mohammad Rafi e Inakoti Ramesh Raja. "Heart Attack Prediction Using Artificial Neural Networks". In 2023 9th International Conference on Advanced Computing and Communication Systems (ICACCS). IEEE, 2023. http://dx.doi.org/10.1109/icaccs57279.2023.10112664.

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Bindela, H. V. R., K. C. Yedubati, R. R. Gosula, E. Snir e B. Rahmani. "Heart Failure Prediction Using Artificial Intelligence Methods". In 2023 IEEE Applied Imagery Pattern Recognition Workshop (AIPR). IEEE, 2023. http://dx.doi.org/10.1109/aipr60534.2023.10440664.

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Rapporti di organizzazioni sul tema "Artificial heart"

Langlois, Lyse, Marc-Antoine Dilhac, Jim Dratwa, Thierry Ménissier, Jean-Gabriel Ganascia, Daniel Weinstock, Luc Bégin e Allison Marchildon. Ethics at the heart of AI. Observatoire international sur les impacts sociétaux de l’intelligence artificielle et du numérique, ottobre 2023. http://dx.doi.org/10.61737/wfym6890.

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This document is the result of a collaborative effort involving specialists in ethics, philosophy, computer science and economics. Its goal is to detail and clarify the role ethics should play in the age of Artificial Intelligence (AI) by highlighting how this notion can be applied and implemented effectively and successfully. It advocates for an ethic focused on reflexivity and dialogue, and it concerns all those involved in the development of AI, whether directly or indirectly. The document also highlights the practical methodological approach used to construct the Montreal Declaration, and also proposes a number of recommendations. In short, this paper argues for the inclusion of a genuine ethical reflection at all stages of the AI developmental process. It is a call for collaboration between ethicists, developers and members of the industry, to truly put ethics at the heart of AI.

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Wagner, Anna, Jon Maakestad, Edward Yarmak e Thomas Douglas. Artificial ground freezing using solar-powered thermosyphons. Engineer Research and Development Center (U.S.), novembre 2021. http://dx.doi.org/10.21079/11681/42421.

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Thermosyphons are an artificial ground-freezing technique that has been used to stabilize permafrost since the 1960s. The largest engineered structure that uses thermosyphons to maintain frozen ground is the Trans Alaska Pipeline, and it has over 124,000 thermosyphons along its approximately 1300 km route. In passive mode, thermosyphons extract heat from the soil and transfer it to the environment when the air temperature is colder than the ground temperature. This passive technology can promote ground cooling during cold winter months. To address the growing need for maintaining frozen ground as air temperatures increase, we investigated a solar-powered refrigeration unit that could operate a thermosyphon (nonpassive) during temperatures above freezing. Our tests showed that energy generated from the solar array can operate the refrigeration unit and activate the hybrid thermosyphon to artificially cool the soil when air temperatures are above freezing. This technology can be used to expand the application of thermosyphon technology to freeze ground or maintain permafrost, particularly in locations with limited access to line power.

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Rinaudo, Christina, William Leonard, Jaylen Hopson, Christopher Morey, Robert Hilborn e Theresa Coumbe. Enabling understanding of artificial intelligence (AI) agent wargaming decisions through visualizations. Engineer Research and Development Center (U.S.), aprile 2024. http://dx.doi.org/10.21079/11681/48418.

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The process to develop options for military planning course of action (COA) development and analysis relies on human subject matter expertise. Analyzing COAs requires examining several factors and understanding complex interactions and dependencies associated with actions, reactions, proposed counteractions, and multiple reasonable outcomes. In Fiscal Year 2021, the Institute for Systems Engineering Research team completed efforts resulting in a wargaming maritime framework capable of training an artificial intelligence (AI) agent with deep reinforcement learning (DRL) techniques within a maritime scenario where the AI agent credibly competes against blue agents in gameplay. However, a limitation of using DRL for agent training relates to the transparency of how the AI agent makes decisions. If leaders were to rely on AI agents for COA development or analysis, they would want to understand those decisions. In or-der to support increased understanding, researchers engaged with stakeholders to determine visualization requirements and developed initial prototypes for stakeholder feedback in order to support increased understanding of AI-generated decisions and recommendations. This report describes the prototype visualizations developed to support the use case of a mission planner and an AI agent trainer. The prototypes include training results charts, heat map visualizations of agent paths, weight matrix visualizations, and ablation testing graphs.

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TIMOTHY J. KNEAFSEY AND KARSTEN PRUESS. LABORATORY EXPERIMENTS ON HEAT-DRIVEN TWO-PHASE FLOWS IN NATURAL AND ARTIFICIAL ROCK FRACTURES. Office of Scientific and Technical Information (OSTI), maggio 1998. http://dx.doi.org/10.2172/778893.

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Kneafsey, T. J., e K. Pruess. Preferential flow paths and heat pipes: Results from laboratory experiments on heat-driven flow in natural and artificial rock fractures. Office of Scientific and Technical Information (OSTI), giugno 1997. http://dx.doi.org/10.2172/527417.

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K. PRUESS AND T. KNEAFSEY. PREFERENTIAL FLOW PATHS AND HEAT PIPES: RESULTS FROM LABORATORY EXPERIMENTS ON HEAT-DRIVEN FLOW IN NATURAL AND ARTIFICIAL ROCK FRACTURES, LEVEL 4 MILESTONE ID: SPL6A5M4, WSB 1.2.3.12.2. Office of Scientific and Technical Information (OSTI), giugno 1997. http://dx.doi.org/10.2172/778887.

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Prajapati, Jinal, Rubina Tabassum e Gaurang Mistry. Comparison of shear bond strength of artificial teeth used with CAD/CAM PMMA versus heat cure acrylic resins for complete denture manufacturing- a systematic review. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, novembre 2023. http://dx.doi.org/10.37766/inplasy2023.11.0065.

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Guidati, Gianfranco, e Domenico Giardini. Joint synthesis “Geothermal Energy” of the NRP “Energy”. Swiss National Science Foundation (SNSF), febbraio 2020. http://dx.doi.org/10.46446/publication_nrp70_nrp71.2020.4.en.

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Near-to-surface geothermal energy with heat pumps is state of the art and is already widespread in Switzerland. In the future energy system, medium-deep to deep geothermal energy (1 to 6 kilometres) will, in addition, play an important role. To the forefront is the supply of heat for buildings and industrial processes. This form of geothermal energy utilisation requires a highly permeable underground area that allows a fluid – usually water – to absorb the naturally existing rock heat and then transport it to the surface. Sedimentary rocks are usually permeable by nature, whereas for granites and gneisses permeability must be artificially induced by injecting water. The heat gained in this way increases in line with the drilling depth: at a depth of 1 kilometre, the underground temperature is approximately 40°C, while at a depth of 3 kilometres it is around 100°C. To drive a steam turbine for the production of electricity, temperatures of over 100°C are required. As this requires greater depths of 3 to 6 kilometres, the risk of seismicity induced by the drilling also increases. Underground zones are also suitable for storing heat and gases, such as hydrogen or methane, and for the definitive storage of CO2. For this purpose, such zones need to fulfil similar requirements to those applicable to heat generation. In addition, however, a dense top layer is required above the reservoir so that the gas cannot escape. The joint project “Hydropower and geo-energy” of the NRP “Energy” focused on the question of where suitable ground layers can be found in Switzerland that optimally meet the requirements for the various uses. A second research priority concerned measures to reduce seismicity induced by deep drilling and the resulting damage to buildings. Models and simulations were also developed which contribute to a better understanding of the underground processes involved in the development and use of geothermal resources. In summary, the research results show that there are good conditions in Switzerland for the use of medium-deep geothermal energy (1 to 3 kilometres) – both for the building stock and for industrial processes. There are also grounds for optimism concerning the seasonal storage of heat and gases. In contrast, the potential for the definitive storage of CO2 in relevant quantities is rather limited. With respect to electricity production using deep geothermal energy (> 3 kilometres), the extent to which there is potential to exploit the underground economically is still not absolutely certain. In this regard, industrially operated demonstration plants are urgently needed in order to boost acceptance among the population and investors.

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Wideman, Jr., Robert F., Nicholas B. Anthony, Avigdor Cahaner, Alan Shlosberg, Michel Bellaiche e William B. Roush. Integrated Approach to Evaluating Inherited Predictors of Resistance to Pulmonary Hypertension Syndrome (Ascites) in Fast Growing Broiler Chickens. United States Department of Agriculture, dicembre 2000. http://dx.doi.org/10.32747/2000.7575287.bard.

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Background PHS (pulmonary hypertension syndrome, ascites syndrome) is a serious cause of loss in the broiler industry, and is a prime example of an undesirable side effect of successful genetic development that may be deleteriously manifested by factors in the environment of growing broilers. Basically, continuous and pinpointed selection for rapid growth in broilers has led to higher oxygen demand and consequently to more frequent manifestation of an inherent potential cardiopulmonary incapability to sufficiently oxygenate the arterial blood. The multifaceted causes and modifiers of PHS make research into finding solutions to the syndrome a complex and multi threaded challenge. This research used several directions to better understand the development of PHS and to probe possible means of achieving a goal of monitoring and increasing resistance to the syndrome. Research Objectives (1) To evaluate the growth dynamics of individuals within breeding stocks and their correlation with individual susceptibility or resistance to PHS; (2) To compile data on diagnostic indices found in this work to be predictive for PHS, during exposure to experimental protocols known to trigger PHS; (3) To conduct detailed physiological evaluations of cardiopulmonary function in broilers; (4) To compile data on growth dynamics and other diagnostic indices in existing lines selected for susceptibility or resistance to PHS; (5) To integrate growth dynamics and other diagnostic data within appropriate statistical procedures to provide geneticists with predictive indices that characterize resistance or susceptibility to PHS. Revisions In the first year, the US team acquired the costly Peckode weigh platform / individual bird I.D. system that was to provide the continuous (several times each day), automated weighing of birds, for a comprehensive monitoring of growth dynamics. However, data generated were found to be inaccurate and irreproducible, so making its use implausible. Henceforth, weighing was manual, this highly labor intensive work precluding some of the original objectives of using such a strategy of growth dynamics in selection procedures involving thousands of birds. Major conclusions, solutions, achievements 1. Healthy broilers were found to have greater oscillations in growth velocity and acceleration than PHS susceptible birds. This proved the scientific validity of our original hypothesis that such differences occur. 2. Growth rate in the first week is higher in PHS-susceptible than in PHS-resistant chicks. Artificial neural network accurately distinguished differences between the two groups based on growth patterns in this period. 3. In the US, the unilateral pulmonary occlusion technique was used in collaboration with a major broiler breeding company to create a commercial broiler line that is highly resistant to PHS induced by fast growth and low ambient temperatures. 4. In Israel, lines were obtained by genetic selection on PHS mortality after cold exposure in a dam-line population comprising of 85 sire families. The wide range of PHS incidence per family (0-50%), high heritability (about 0.6), and the results in cold challenged progeny, suggested a highly effective and relatively easy means for selection for PHS resistance 5. The best minimally-invasive diagnostic indices for prediction of PHS resistance were found to be oximetry, hematocrit values, heart rate and electrocardiographic (ECG) lead II waves. Some differences in results were found between the US and Israeli teams, probably reflecting genetic differences in the broiler strains used in the two countries. For instance the US team found the S wave amplitude to predict PHS susceptibility well, whereas the Israeli team found the P wave amplitude to be a better valid predictor. 6. Comprehensive physiological studies further increased knowledge on the development of PHS cardiopulmonary characteristics of pre-ascitic birds, pulmonary arterial wedge pressures, hypotension/kidney response, pulmonary hemodynamic responses to vasoactive mediators were all examined in depth. Implications, scientific and agricultural Substantial progress has been made in understanding the genetic and environmental factors involved in PHS, and their interaction. The two teams each successfully developed different selection programs, by surgical means and by divergent selection under cold challenge. Monitoring of the progress and success of the programs was done be using the in-depth estimations that this research engendered on the reliability and value of non-invasive predictive parameters. These findings helped corroborate the validity of practical means to improve PHT resistance by research-based programs of selection.

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Wilson, Thomas E., Avraham A. Levy e Tzvi Tzfira. Controlling Early Stages of DNA Repair for Gene-targeting Enhancement in Plants. United States Department of Agriculture, marzo 2012. http://dx.doi.org/10.32747/2012.7697124.bard.

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Gene targeting (GT) is a much needed technology as a tool for plant research and for the precise engineering of crop species. Recent advances in this field have shown that the presence of a DNA double-strand break (DSB) in a genomic locus is critical for the integration of an exogenous DNA molecule introduced into this locus. This integration can occur via either non-homologous end joining (NHEJ) into the break or homologous recombination (HR) between the broken genomic DNA and the introduced vector. A bottleneck for DNA integration via HR is the machinery responsible for homology search and strand invasion. Important proteins in this pathway are Rad51, Rad52 and Rad54. We proposed to combine our respective expertise: on the US side, in the design of zincfinger nucleases (ZFNs) for the induction of DNA DSBs at any desired genomic locus and in the integration of DNA molecules via NHEJ; and on the Israeli side in the HR events, downstream of the DSB, that lead to homology search and strand invasion. We sought to test three major pathways of targeted DNA integration: (i) integration by NHEJ into DSBs induced at desired sites by specially designed ZFNs; (ii) integration into DSBs induced at desired sites combined with the use of Rad51, Rad52 and Rad54 proteins to maximize the chances for efficient and precise HR-mediated vector insertion; (iii) stimulation of HR by Rad51, Rad52 and Rad54 in the absence of DSB induction. We also proposed to study the formation of dsT-DNA molecules during the transformation of plant cells. dsT-DNA molecules are an important substrate for HR and NHEJ-mediatedGT, yet the mode of their formation from single stranded T-DNA molecules is still obscure. In addition we sought to develop a system for assembly of multi-transgene binary vectors by using ZFNs. The latter may facilitate the production of binary vectors that may be ready for genome editing in transgenic plants. ZFNs were proposed for the induction of DSBs in genomic targets, namely, the FtsH2 gene whose loss of function can easily be identified in somatic tissues as white sectors, and the Cruciferin locus whose targeting by a GFP or RFP reporter vectors can give rise to fluorescent seeds. ZFNs were also proposed for the induction of DSBs in artificial targets and for assembly of multi-gene vectors. We finally sought to address two important cell types in terms of relevance to plant transformation, namely GT of germinal (egg) cells by floral dipping, and GT in somatic cells by root and leave transformation. To be successful, we made use of novel optimized expression cassettes that enable coexpression of all of the genes of interest (ZFNs and Rad genes) in the right tissues (egg or root cells) at the right time, namely when the GT vector is delivered into the cells. Methods were proposed for investigating the complementation of T-strands to dsDNA molecules in living plant cells. During the course of this research, we (i) designed, assembled and tested, in vitro, a pair of new ZFNs capable of targeting the Cruciferin gene, (ii) produced transgenic plants which expresses for ZFN monomers for targeting of the FtsH2 gene. Expression of these enzymes is controlled by constitutive or heat shock induced promoters, (iii) produced a large population of transgenic Arabidopsis lines in which mutated mGUS gene was incorporated into different genomic locations, (iv) designed a system for egg-cell-specific expression of ZFNs and RAD genes and initiate GT experiments, (v) demonstrated that we can achieve NHEJ-mediated gene replacement in plant cells (vi) developed a system for ZFN and homing endonuclease-mediated assembly of multigene plant transformation vectors and (vii) explored the mechanism of dsTDNA formation in plant cells. This work has substantially advanced our understanding of the mechanisms of DNA integration into plants and furthered the development of important new tools for GT in plants.

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