138 research outputs found
The comparative effects of esmolol and amiodarone on isolated coronary artery bypass grafts
Background/aim: Esmolol and amiodarone are two most commonly used antiarrhythmic drugs in coronary artery bypass grafting (CABG) surgery. Nevertheless, blockade of beta-2 receptors by increasing doses raise concerns about possible vasospasms. We studied the vasoactive effects of amiodarone and esmolol on left internal mammary artery (LIMA), radial artery (RA), and saphenous vein (SV) grafts. Materials and methods: After determining the presence of functional smooth muscle and endothelial layers, the responses of submaximally preconstricted graft samples were recorded in a tissue bath system. A total of 96 graft samples from 40 patients were used: 16 LIMA, 16 RA, and 16 SV grafts for each drug. Esmolol and amiodarone were added to reservoirs separately, starting from a concentration of 10-8 M until a concentration of 10-4 M. Results: Although both drugs caused vasodilatation, amiodarone exhibited a more potent vasodilatory effect than esmolol (P < 0.0001 for LIMA, P = 0.0128 for RA, and P < 0.0001 for SV). The vasodilatation rates with esmolol were 48.99 +/- 1. 2.28% in LIMA, 49.77 +/- 3.03% in RA, and 41.90 +/- 4.05% in SV grafts and with amiodarone they were 71.65 +/- 5.18% in LIMA, 58.61 +/- 5.87% in RA, and 65.07 +/- 4.09% in SV grafts. Conclusion: This in vitro study revealed that even increasing doses of both drugs induce vasodilatation of CABG grafts, with amiodarone having a more potent vasodilatory effect than esmolol
Proactive controller assignment schemes in SDN for fast recovery
© 2020 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.A sizeable software defined network with a single controller responsible for all forwarding elements is potentially failure-prone and inadequate for dynamic network loads. To this end, having multiple controllers improves resilience and distributes network control overhead. However, when there is a disruption in the control plane, a rapid and performant controller-switch assignment is critical, which is a challenging technical question. In this work, we propose a proactive switch assignment approach in case of controller failures using a genetic algorithm based heuristic that considers controller load distribution, reassignment cost and probability of failure. Moreover, we compare the performance of our scheme with random and greedy algorithms. Experiment results show that our proposed PREFCP framework has better performance in terms of probability of failure and controller load distributio
Expansive networks : exploiting spectrum sharing for capacity boost and 6G vision
Adaptive capacity with cost-efficient resource provisioning is a crucial capability for future 6G networks. In this work, we conceptualize "expansive networks" which refers to a networking paradigm where networks should be able to extend their resource base by opportunistic but self-controlled expansive actions. To this end, we elaborate on a key aspect of an expansive network as a concrete example: Spectrum resource at the PHY layer. Evidently, future wireless networks need to provide efficient mechanisms to coexist in the licensed and unlicensed bands and operate in expansive mode. In this work, we first describe spectrum sharing issues and possibilities in 6G networks for expansive networks. We then present security implications of expansive networks, an important concern due to more open and coupled systems in expansive networks. We also discuss two key enablers, namely distributed ledger technology (DLT) and network intelligence via machine learning, which are promising to realize expansive networks for the spectrum sharing aspect
The Effect of Speciality Designated Core Exercises on Upper Exterimity Posture Structures of Male High School Students
The aim of this study is to research on the effect of core exercises on the upper extremity posture structure of young individuals. 30 male students between 16 to 18 years old studying in a high school in the province of Elazig and not doing regular sport volunteered for this study. The participants were randomly divided into two as the subject group and the control group; each group was formed with 15 people. Out of the groups formed, the subject group carried out specially designated core exercises for 8 weeks, and for 3 days each week. The control group didn't do any work; they continued their normal lives. Before and after the study, the height, weight, body mass index, bodily fat percentage, upper extremity posture(from the front, back, right and left)of the subject and control groups formed were measured and the Adams(stoop) test was applied. The data obtained were analyzed through SPSS 22.0 statistical program. For the in-group and intergroup comparisons, ındependent samples T test and paired samples T test were used. After the statistical analysis, during the initial and subsequent test comparisons of the control group, no difference was detected in measurements apart from the one for shoulders from the anterior side. Statistical differences were determined for a lot of values during the comparison of the initial and subsequent test results of the subject group and during the comparison of the differences between the initial and subsequent test results of the subject and control group. In conclusion, it was determined that core exercises made a positive impact on the upper extremity posture structures of male individuals between the ages of 16 and 18.
Symptomatic huge pericardial cyst: a case report
Mediastinal kistler nadir gözlenen, konjenital, neoplastik ve inflamatuar kaynaklı patolojilerdir. Basit
perikardiyal kistler tüm yaş gruplarında görülmekle beraber sıklıkla yetişkin yaş grubunda gözlenmektedir.
Perikardiyal kistler tüm mediastinal kistler arasında %7 gibi bir oranda gözlenmektedir. Hastaların kliniği
sıklıkla asemptomatik seyretmektedir. Semptomlar nadir gözlenmekle beraber %20-30 olguda semptomatik olup
ağrı, nefes darlığı, taşipne ve öksürük en sık gözlenen semptomlardır. Kistin kardiyak basısına bağlı olarak
hipotansiyon, aritmi, atrial fibrilasyon ya da ani kardiyak ölüm semptomlarda gözlenebilmektedir. X-ray,
bilgisayarlı tomografi, ekokardiografi gibi tetkikler ile saptanmaktadır. Yazımızda 35 yaşında, medikal tedaviye
dirençli hipotansiyon, aritmi ve nefes darlığı olan, sağ atriuma bası yapan perikardiyal kist olgusunu sunduk.Mediastinal cysts are uncommon and results from congenital, neoblastic or inflamatuar abnormalities.
Pericardial cyst may occur in patients of all ages, but commonly present in adults. The overall incidence of
pericardial cyst is 7% in mediastinal cysts. The clinical presentation is commonly asymtomatic. Pain, tachpnea,
dsypne and cough is the most common symptoms. Tachycardie, hypotansion, arytmi and sudden death are usually
because of cardiac compression by the cystic mass.They are commonly found incidentally upon chest
radiography, computed tomography or echocardiograph. We present, herein, the case of a 35-year-old female
with a symptoms of dsypne, hypotansion and atrial arrhythmia resistant to medical therapies with finding of a
pericardial cyst compression to the lateral wall of the right atrium
Patient satisfaction with hemodialysis catheter in patients with chronic renal failure
Amaç: Kronik böbrek yetmezliği bulunan, renal transplant yapılamayan hastalar hemodiyaliz bağımlı olarak yaşamaktadır. Hemodiyalize giriş yolu olarak arteriovenöz şant (AV) altın standart yöntemlerdir. AV şant açılamayan ya da AV şant mevcut olup henüz olgunlaşmamış hastalarda hemodiyaliz'e girebilmek için hemodiyaliz kateterleri kullanılmaktadır. Hemodiyaliz kateterleri sıklıkla femoral, subklaviyan ve juguler venlere uygulanmakla beraber nadir olarak torakolomber yaklaşımla inferior vena kavaya da takılmaktadır. Çalışmamızda hemodiyaliz amacıyla kullanılan kateterlerin hasta memnuniyeti ve yaşam kalitesine etkilerini incelemeyi amaçladık. Yöntem: Kliniğimizde ocak 2011- mayıs 2012 yılları arasında hemodiyaliz amacıyla arteriyovenöz şant açılan ve katater takılan topla 139 hasta çalışmaya alındı. Hastalardan 91 erkek 48 kadın, yaş ortalaması 60,85 ±14,6 (min: 54, max:83) idi. Hastalar arasında demografik olarak anlamlı fark yoktu. Bu hastalar ile tek tek görülerek takılan kateter ve bölgelere göre menuniyet durumları araştırıldı. Bulgular: Takılan kataterlere bağlı olarak olguların %69.06'da herhangi bir şikayet gözlenmedi. En sık gözlenen şikayet ağrı olup olguların %17.9'da bu şikayet mevcut idi. Diğer şikayetler sırası ile %9.3 olguda görünümünden rahatsız olma ve %3.5 olguda yaşam kalitesinin olumsuz etkilenme olarak belirlendi. Komplikasyon olarak %10.7 oranında katater yeri enfeksiyonu ve %9.3 oranında katater oklüzyonu tespit edildi. Femoral bölgeye takılan kataterlerin enfeksiyon oranı %85 oranında tespit edildi. Sonuç: Kronik böbrek yetmezliği bulunan olgularda hemodiyaliz amacıyla katater takılacağı durumlarda öncelikli olarak juguler bölgenin tercih edilmesi gerektiği, juguler bölgenin uygun olmadığı durumlarda yüksek enfeksiyon oranları sebebiyle subklaviyan bölgenin ve en son seçenek olarak femoral bölgenin tercih edilmesi gerektiğini düşünüyoruz. Katater takılacak bölge ve oluşabilecek şikayetler hakkında hastaların bilgilendirilmesinin hasta memnuniyetini arttıracağı kanaatindeyizPurpose: Patients with chronic renal failure, for whom renal transplantation is not an option, depend on hemodialysis for life. An Arteriovenous shunt is the gold standart access site for hemodialysis. In patients without an AV shunt or with an immature shunt, a hemodialysis catheter is used. Subclavian, femoral and juguler veins are common sites for hemodiaylsis catheter. Patients may have different complaints with the catheter according to the insertion site. In our study, we aimed to investigate the impact of the site of the catheter on patients' comfort and social lives. Method: Between January 2011 and May 2012, 48 women and 91 men (139 patients) who underwent AV shunt operation in our clinic. The mean age of the patients was 60.85±14.6(min:54, max:83) years. Every patient was interviewed individually about his comfort and satisfaction with the catheter.There were no statistically significant demographic differences among patients. Results: When insertion of a hemodialysis catheter is planned in patients with chronic renal failure, internal juguler vein is the optimum site and should be preferred in the first line. In cases which juguler vein is not available, subclavian vein is the next preferred site and he femoral vein, due to its high rates of infection, is the last place to choose for the insertion of a hemodialysis catheter. Conclusion: We believe that informing patients about the site of the catheter and the possible disadvantages will improve the patient satisfaction
MERLINS – Moving Target Defense Enhanced with Deep-RL for NFV In-Depth Security
Moving to a multi-cloud environment and service-based architecture, 5G and future 6G networks require additional defensive mechanisms to protect virtualized network resources. This paper presents MERLINS, a novel architecture generating optimal Moving Target Defense (MTD) policies for proactive and reactive security of network slices. By formally modeling telecommunication networks compliant with Network Function Virtualization (NFV) into a multi-objective Markov Decision Process (MOMDP), MERLINS uses deep Reinforcement Learning (deep-RL) to optimize the MTD strategy that considers security, network performance, and service level requirements. Practical experiments on a 5G testbed showcase the feasibility as well as restrictions of MTD operations and the effectiveness in mitigating malware infections. It is observed that multi-objective RL (MORL) algorithms outperform state-of-the-art deep-RL algorithms that scalarize the reward vector of the MOMDP. This improvement by a factor of two leads to a better MTD policy than the baseline static counterpart used for the evaluation
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