79 research outputs found

    Venographic classification and long-term surgical treatment outcomes for axillary-subclavian vein thrombosis due to venous thoracic outlet syndrome (Paget-Schroetter syndrome)

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    OBJECTIVE: We assessed the clinical presentation, operative findings, and surgical treatment outcomes for axillary-subclavian vein (AxSCV) thrombosis due to venous thoracic outlet syndrome (VTOS). METHODS: We performed a retrospective, single-center review of 266 patients who had undergone primary surgical treatment of VTOS between 2016 and 2022. The clinical outcomes were compared between the patients in four treatment groups determined by intraoperative venography. RESULTS: Of the 266 patients, 132 were male and 134 were female. All patients had a history of spontaneous arm swelling and idiopathic AxSCV thrombosis, including 25 (9%) with proven pulmonary embolism, at a mean age of 32.1 ± 0.8 years (range, 12-66 years). The timing of clinical presentation was acute (\u3c15 days) for 132 patients (50%), subacute (15-90 days) for 71 (27%), and chronic (\u3e90 days) for 63 patients (24%). Venography with catheter-directed thrombolysis or thrombectomy (CDT) and/or balloon angioplasty had been performed in 188 patients (71%). The median interval between symptom onset and surgery was 78 days. After paraclavicular thoracic outlet decompression and external venolysis, intraoperative venography showed a widely patent AxSCV in 150 patients (56%). However, 26 (10%) had a long chronic AxSCV occlusion with axillary vein inflow insufficient for bypass reconstruction. Patch angioplasty was performed for focal AxSCV stenosis in 55 patients (21%) and bypass graft reconstruction for segmental AxSCV occlusion in 35 (13%). The patients who underwent external venolysis alone (patent or occluded AxSCV; n = 176) had a shorter mean operative time, shorter postoperative length of stay and fewer reoperations and late reinterventions compared with those who underwent AxSCV reconstruction (patch or bypass; n = 90), with no differences in the incidence of overall complications or 30-day readmissions. At a median clinical follow-up of 38.7 months, 246 patients (93%) had no arm swelling, and only 17 (6%) were receiving anticoagulation treatment; 95% of those with a patent AxSCV at the end of surgery were free of arm swelling vs 69% of those with a long chronic AxSCV occlusion (P \u3c .001). The patients who had undergone CDT at the initial diagnosis were 32% less likely to need AxSCV reconstruction at surgery (30% vs 44%; P = .034) and 60% less likely to have arm swelling at follow-up (5% vs 13%; P \u3c .05) vs those who had not undergone CDT. CONCLUSIONS: Paraclavicular decompression, external venolysis, and selective AxSCV reconstruction determined by intraoperative venography findings can provide successful and durable treatment for \u3e90% of all patients with VTOS. Further work is needed to achieve earlier recognition of AxSCV thrombosis, prompt usage of CDT, and even more effective surgical treatment

    A Case Study on Influence of Utilizing Hill-type Muscles on Mechanical Efficiency of Biped Running Gait

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    The presence of compliant elements in biped running mechanisms generates a smoother motion and decreases impact forces. Biological creatures that have a complicated actuation system with parallel and series elastic elements in their muscles demonstrate very efficient and robust bipedal gaits. The main difficulty of implementing these systems is duplicating their complicated dynamics and control. This paper studies the effects of an actuation system, including Hill-type muscles on the running efficiency of a kneed biped robot model with point feet. In this research, we implement arbitrary trajectories compatible with the initial condition of the robot, and we calculate the necessary muscle forces using an analytical inverse dynamics model. To verify the results, we execute the direct dynamics of the robot with the calculated control inputs to generate the robot’s trajectory. Finally, we calculate the contractile element force of the muscles and its cost of transport, and we investigate the effects of the muscles’ elements on reducing or increasing the cost of transport of the gait and maximum actuating forces.Наявність податливих елементів у механізмах виконання двоногої ходи породжує плавність руху і зменшує сили удару. Біологічні істоти, які мають складну систему спрацьовування з паралельними і серіями еластичних елементів в м'язах, демонструють дуже ефективну і надійну двоногу ходу. Основними труднощами реалізації цих систем є дублювання їх складної динаміки і контролю. Вивчаються наслідки спрацьовування системи, в тому числі м'язів типу Хілла на ефективність роботи коліна у моделі двоногої ходи. У цьому дослідженні введено довільні траєкторії, сумісні з початковим станом робота, і розраховано необхідні сили м'язів за допомогою аналітичної зворотної моделі динаміки. Для перевірки результатів виконано пряму динаміку робота з обчисленням імпульсів управління для генерації траєкторії робота. Розраховано скорочувальну силу елемента м'язів і вартість його передачі для робота, і досліджено вплив елементів м'язів на зменшення або збільшення витрат на ходу і максимальні виконавчі сили

    COVID-19 under spotlight: A close look at the origin, transmission, diagnosis, and treatment of the 2019-nCoV disease

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    Months after the outbreak of a new flu-like disease in China, the entire world is now in a state of caution. The subsequent less-anticipated propagation of the novel coronavirus disease, formally known as COVID-19, not only made it to headlines by an overwhelmingly high transmission rate and fatality reports, but also raised an alarm for the medical community all around the globe. Since the causative agent, SARS-CoV-2, is a recently discovered species, there is no specific medicine for downright treatment of the infection. This has led to an unprecedented societal fear of the newly born disease, adding a psychological aspect to the physical manifestation of the virus. Herein, the COVID-19 structure, epidemiology, pathogenesis, etiology, diagnosis, and therapy have been reviewed. © 2020 Wiley Periodicals, Inc

    Hollow-core Optical Fiber Gas Lasers (HOFGLAS): a review [Invited]

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    International audienceThe development of hollow core photonic crystal fibers with low losses over a broad spectral region in the near IR enabled the demonstration of a novel laser type - Hollow-core Optical Fiber Gas Laser (HOFGLAS). The laser combines attractive features of fiber lasers such as compactness and long interaction length of pump and laser radiation with those of gas lasers such as the potential for high output power and narrow line width. This paper summarizes recent developments and describes the demonstration of C2H2 and HCN prototype lasers. Avenues to extend laser emission further into the IR are discussed

    Application of integrated risk-based approach to safety design of high speed LNG powered vessels

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    The shipping industry is facing increasing claims to meet restricted environmentalregulations and escalating operation costs. To mitigate these problems, cleaner andmore cost-effective fuels are required to power the new generation of vessels.Currently, the high speed ferry sector is using lightweight diesel engines burningdistillate fuels. However, the increasing demand for higher installed power requirement in such vessels, coupled with fuel costs, has placed further constraints onthis sector (Bennett 2011). Liquefied natural gas (LNG), which meets these newrequirements, is now becoming popular as an alternative fuel in this sector.Liquefied natural gas is obtained through natural gas liquefaction by cooling itto approximately 162 °C at atmospheric pressure. This process reduces the volumeapproximately 600 times; hence, it is more competent for transportation and storagecompared to conventional hydrocarbon fuels (Ramos et al. 2014)

    A Study Of The Relation Between IQ And Personality Types Among Male And Female Students Of Tabriz

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    Background: Psychologists have been thinking that some personality types may have a higher IQ comparing with the other types, and this could be considered as a general belief. Eysenck, the eminent British psychologist, described the introverted people to have a higher. Intelligence comparing with the extroverted people. Materials and Methods: We maintain two objectives from this study. Firstly if there is a relation between the IQ and personality types or not and secondly the mean IQ of which group is higher and thirdly, what is the relation between sexes. Results: 297 students were selected randomly from Tabriz University and Tabriz Medical Sciences University. Every examination was given both Raven IQ test and Eysenck personality inventory and examination answered the both tests at the same time. Both tests were evaluated by the standard scoring system. The results of both tests were extracted then statistical evaluations ofx and t-test were done. No significant and meaningful relation was found between IQ and personality types pf Eysenck ( introversion- extroversion, neuroticism, emotion stability) among male and female students. Also introverted students and extroverted students did not have significant differences in the mean of IQ. Conclusion: Altogether these kinds of findings seem to be interesting, judging about psychological and behavioral characteristic of people needs more studies, and a single IQ or personality test is not sufficient. Therefore reaching an exact conclusion as a scientific fact will be possible by further researches

    Joint Closed-Loop Power Control and Base Station Assignment for DS-CDMA Receiver in Multipath Fading Channel with Adaptive Beamforming Method

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    In this paper, we propose smart step closed-loop power control (SSPC) algorithm and base station assignment based on minimizing the transmitter power (BSAMTP) technique in a direct sequence-code division multiple access (DS-CDMA) receiver in the presence of frequency-selective Rayleigh fading. This receiver consists of three stages. In the first stage, with conjugate gradient (CG) adaptive beamforming algorithm, the desired users’ signal in an arbitrary path is passed and the inter-path interference is canceled in other paths in each RAKE finger. Also in this stage, the multiple access interference (MAI) from other users is reduced. Thus, the matched filter (MF) can be used for the MAI reduction in each RAKE finger in the second stage. Also in the third stage, the output signals from the matched filters are combined according to the conventional maximal ratio combining (MRC) principle and then are fed into the decision circuit of the desired user. The simulation results indicate that the SSPC algorithm and the BSA-MTP technique can significantly improve the network bit error rate (BER) in comparison with other algorithms. Also, we observe that significant savings in total transmit power (TTP) are possible with our proposed methods
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