119 research outputs found

    Trapped by the Entrapment.

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    Popliteal entrapment syndrome results from extrinsic compression of the popliteal artery by the surrounding musculotendinous structures and is a rare cause of limb ischaemia. The purpose of this report is to highlight potential mistakes in the management of popliteal entrapment. In 2000, a 23 year old man underwent a popliteal to popliteal artery bypass surgery for what was initially diagnosed as a traumatic popliteal artery thrombosis. After being initially lost to follow up for 13 years, this "unspecified traumatic" thrombosis led to several inappropriate endovascular and open procedures misinterpreted as being caused by late graft failure. These included thrombectomy, aneurysmorrhaphy, polytetrafluoroethylene covered stent graft, a redo femoropopliteal bypass, and bypass thrombolysis. The diagnosis was reached 19 years after the initial surgery, when the patient underwent a redo bypass using a retrogeniculate approach. An abnormal lateral insertion of the gastrocnemius muscle medial head, and its accessory slip, constricted the artery, and also involved the popliteal vein (Type V), thus explaining previous revascularisation failures. Surgery consisted of resecting the accessory slip and the aneurysmal bypass. The artery was reconstructed with the cephalic vein. The patient was discharged on clopidogrel 75 mg, with no further complication, and a patent bypass at six months. Based on post-operative imaging (duplex ultrasound and magnetic resonance imaging), with forced plantarflexion and dorsiflexion, asymptomatic popliteal entrapment was also present on the contralateral side. The finding of an isolated popliteal artery lesion in a young individual should be considered to be caused by popliteal artery entrapment, unless proven otherwise. Definitive surgical release of the popliteal artery should be favoured over other strategies

    A Gardening Session Turns Into a Life Threatening Aortic Transection.

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    Penetrating injuries to the sub-diaphragmatic aorta are challenging, with high mortality rates. Most penetrating aortic trauma results from gunshots or stab wounds. This case reports a successful aortic bypass, following partial aortic transection caused by an accidental fall on a utility knife. A healthy 82 year old woman was admitted to the emergency department following penetrating abdominal trauma following an accidental fall on an 18 cm long utility knife. On admission, the patient was haemodynamically stable, with no neurological deficit. Computed tomography angiography revealed multiple abdominal injuries to the stomach, duodenum, L4-L5 left vertebrae, and infrarenal abdominal aorta. The patient underwent urgent midline laparotomy, followed by successful aortic repair using a 14 mm polyester graft. The gastric and duodenal lesions were repaired with an omental patch. The post-operative course was uneventful. Penetrating abdominal trauma with visceral lesions and aortic transection are high risk injuries, albeit rarely described in the literature. A low threshold for imaging, and multidisciplinary management by vascular and visceral surgeons are essential for timely recognition and successful intervention

    PID Controller Tuning Using Bode's Integrals

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    A new method for PID controller tuning based on Bode's integrals is proposed. It is shown that the derivatives of amplitude and phase of a plant model with respect to frequency can be approximated by Bode's integrals without any model of the plant. This information can be used to design a PID controller for slope adjustment of the Nyquist diagram and improve the closed-loop performance. Besides, the derivatives can be also employed to estimate the gradient and the Hessian of a frequency criterion in an iterative PID controller tuning method. The frequency criterion is defined as the sum of squared errors between the desired and measured gain margin, phase margin and crossover frequency. The method benefits from specific feedback relay tests to determine the gain margin, the phase margin and the crossover frequency of the closed-loop system. Simulation examples and experimental results illustrate the effectiveness and the simplicity of the proposed method to design and tune the PID controllers

    PID CONTROLLER DESIGN WITH SPECIFICATIONS ON THE INFINITY-NORM OF SENSITIVITY FUNCTIONS

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    Alguns serviços da administração pública requerem uma mudança em seu modelo de funcionamento, a fim de assegurar mobilidade, agilidade, eliminação de retrabalho e melhores maneiras de disponibilização da informação. Nesse cenário, o Batalhão de Trânsito da Polícia Militar do Estado de Mato Grosso, devido ao crescimento da malha rodoviária urbana, ao excesso de imprudência dos condutores de veículos, à quantidade reduzida de policiais para atender a grande demanda do estado, buscou evoluir em seus processos de fiscalização e autuação. Um indicador importante dessa crítica situação é o fato de um percentual elevado de infrações aplicadas aos condutores de veículos não se concretizarem em efetiva cobrança devido à demora em dar entrada aos dados nos sistemas da segurança pública e do Departamento de Trânsito, e também para processar essas informações e a posterior intimação do infrator. O período legal para todo esse processo acontecer é sempre extrapolado devido à falta de recursos que possam dar agilidade a esse processo que ainda é manual, off-line e repetitivo, considerando que os dados são digitados novamente por órgãos diferentes, porém do mesmo Estado. O acesso à informação dos condutores, dos veículos e das infrações de uma forma ágil e consolidada, provê hoje uma tomada de decisão mais rápida e assertiva pelos policiais em atividade nos pontos de fiscalização. Considerando ainda que a natureza dessa atividade da Polícia Militar não é em pontos fixos na cidade e a estratégia é sempre atuar em pontos diferentes e de trânsito confuso e conflitante. Uma forma de proporcionar esse benefício foi com a disponibilização de recursos tecnológicos para o acesso móvel à base de dados do Departamento de Trânsito, tanto para as consultas quanto para a autuação e sua consequente geração de infração. A MTI viabilizou o processo de contratação do serviço em setembro/13. Foi possível iniciar o projeto em dezembro/13 com o Batalhão de Trânsito da Polícia Militar. A solução foi implantada em março/14 com a disponibilização de 100 dispositivos móveis, porém foi liberado efetivamente em produção somente em maio/14. A expansão para 300 dispositivos ocorreu em julho/2016. Em setembro/2016 já foi expandido novamente para atender aos processos de vistoria de veículos no Detran-MT.13 p.Gestão PúblicaGovernançaTecnologia da Informação e ComunicaçãoIniciativa premiada no 21º Concurso Inovação no Setor Público sob responsabilidade de Sandro Luis Brandão Campos Assessor da Presidência – analista de TI. Iniciativas premiadas no 21º Concurso Inovação no Setor Público 2016. Área temática: Processos organizacionais, serviços ou políticas públicas no Poder Executivo estadual/ distrita

    Severe Lactic Acidosis in a Critically Ill Child: Think About Thiamine! A Case Report.

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    In this article, we presented a teenager, in maintenance chemotherapy for leukemia, who was admitted for digestive symptoms related to a parasitic infection and required nutritional support with parenteral nutrition. After 6 weeks, his condition worsened with refractory shock of presumed septic origin, necessitating extracorporeal membrane oxygenation. Despite hemodynamic stabilization, his lactic acidosis worsened until thiamine supplementation was started. Lactate normalized within 12 hours. Thiamine is an essential coenzyme in aerobic glycolysis, and deficiency leads to lactate accumulation through anaerobic glycolysis. Thiamine deficiency is uncommon in the pediatric population. However, it should be considered in patients at risk of nutritional deficiencies with lactic acidosis of unknown origin

    Intra-arterial vasodilators infusion for management of reversible cerebral vasoconstriction syndrome in a 12-year-old girl: A case report.

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    Reversible cerebral vasoconstriction syndrome (RCVS) is a vascular disease characterized by diffuse transient vasoconstriction and vasodilatation of the cerebral arteries. It is commonly associated with recurrent severe acute headaches with or without focal neurological deficits due to hemorrhages, infarcts, and even posterior reversible encephalopathy syndrome. The optimal management of acute neurologic deficits caused by RCVS is still uncertain. Calcium channel blockers (CCBs) such as nimodipine or verapamil have been reported to be effective in adult series. Intra-arterial injection of nimodipine, verapamil, and milrinone has recently been demonstrated to be safe and effective for treating severe segmental vasoconstriction in adults. CCBs are the most used treatment in the available pediatric literature. Intra-arterial vasodilators have been reported in some rare pediatric reports with more severe diseases, but their utility is still under investigation. We report a case of a 12-year-old girl who underwent a severe course of RCVS complicated by multiple cerebral infarcts, treated by several sessions of intra-arterial vasodilators infusion

    A new dynamic module for in-situ nanomechanical testing at high strain rate

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    In-situ nanomechanical testing is commonly used to probe surface mechanical properties of bulk materials or thin films, like hardness, Young’s modulus, Yield stress…Actually most of the instruments can measure these properties only statically, i.e. a low frequency, leading to property measurement only at low strain rate (usually 10-1s-1 by nanoindentation). This is mainly caused by the low resonance frequency of the system, preventing making tests at higher speed. Performing high dynamic measurements could bring new information on materials properties like deformation mechanism at high strain rate, or high dynamic fatigue properties. A new high dynamic module usable for in-situ mechanical testing has been developed. It is composed of a small piezotube attached directly behind the tip. Because of the small dimensions of the module, his resonance frequency is very high (higher than 50kHz) in comparison to classical nanomechanical testers, permitting to perform and measure precisely the signals at very high frequency. Moreover, it can be used as a sensor and as an actuator, in x, y and z directions which gives to this module a very large range of measurements. Firstly, the characteristics, the performances and the limits of the new high dynamic module will be presented. Secondly some indentations experiments performed at high strain rate on nanocrystalline nickel with the in-situ nanomechanical tester (Alemnis Gmbh) equipped with the high dynamic will be presented and discussed (Fig. 1). Finally, some micropillar compression at high strain rate on the same material will be described and discussed

    Low-energy electron holographic imaging of individual tobacco mosaic virions

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    Modern structural biology relies on NMR, X-ray crystallography and cryo-electron microscopy for gaining information on biomolecules at nanometer, sub-nanometer or atomic resolution. All these methods, however, require averaging over a vast ensemble of entities and hence knowledge on the conformational landscape of an individual particle is lost. Unfortunately, there are now strong indications that even X-ray free electron lasers will not be able to image individual molecules but will require nanocrystal samples. Here, we show that non-destructive structural biology of single particles has now become possible by means of low-energy electron holography. As an example, individual tobacco mosaic virions deposited on ultraclean freestanding graphene are imaged at one nanometer resolution revealing structural details arising from the helical arrangement of the outer protein shell of the virus. Since low-energy electron holography is a lens-less technique and since electrons with a deBroglie wavelength of approximately 1 Angstrom do not impose radiation damage to biomolecules, the method has the potential for Angstrom resolution imaging of single biomolecules

    Improvement in perioperative care in pediatric cardiac surgery by shifting the primary focus of treatment from cardiac output to perfusion pressure: Are beta stimulants still needed?

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    An important aspect of perioperative care in pediatric cardiac surgery is maintenance of optimal hemodynamic status using vasoactive/inotropic agents. Conventionally, this has focused on maintenance of cardiac output rather than perfusion pressure. However, this approach has been abandoned in our center in favor of one focusing primarily on perfusion pressure, which is presented here and compared to the conventional approach. A retrospective study. Regional center for congenital heart disease. University Hospital of Lausanne, Switzerland. All patients with Aristotle risk score ≥8 that underwent surgery from 1996 to 2012 were included. Patients operated between 1996 and 2005 (Group 1: 206 patients) were treated according to the conventional approach. Patients operated between 2006 and 2012 (Group 2: 217 patients) were treated according to our new approach. All patients had undergone surgery for correction or palliation of congenital cardiac defects. Mortality, duration of ventilation and inotropic treatment, use of ECMO, and complications of poor peripheral perfusion (need for hemofiltration, laparotomy for enterocolitis, amputation). The two groups were similar in age and complexity. Mortality was lower in group 2 (7.3% in group 1 vs 1.4% in group 2, P < .005). Ventilation times (hours) and number of days on inotropic/vasoactive treatment (all agents), expressed as median and interquartile range [Q1-Q3] were shorter in group 2: 69 [24-163] hours in group 1 vs 35 [22-120] hours in group 2 (P < .01) for ventilation, and 9 [3-5] days in group 1 vs 7 [2-5] days in group 2 (P < .05) for inotropic/vasoactive agents. There were no differences in ECMO usage or complications of peripheral perfusion. Results in pediatric cardiac surgery may be improved by shifting the primary focus of perioperative care from cardiac output to perfusion pressure

    Leukemoid Reaction in Infant Pertussis: Is There a Place for Hydroxyurea? A Case Report.

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    A 73-days old infant of 34 weeks' gestation was hospitalized with a co-infection of respiratory syncytial virus (RSV) and <i>Bordetella pertussis (BP)</i> . She required invasive ventilation for 9 days in the context of malignant pertussis with persistent hypoxemia and hypercapnia secondary to a leukemoid reaction. Despite an increase of white blood cell (WBC) count up to 70 G/L and ensuing pulmonary hypertension, no hemodynamic compromise occurred. Without clear indication for leukapheresis nor exchange transfusion, an off-label treatment with hydroxyurea was given for 5 days with gradual decrease of WBC count, without any complication and hospital discharge on day 29. To our knowledge, no effective therapy for malignant pertussis has been described in the literature and complications are frequent with leukoreduction procedures. We discuss an alternative to invasive procedures in young infants to fulfill the need to decrease rapidly leukocyte counts in a leukemoid reaction associated with <i>Bordetella pertussis</i> infection. To our knowledge, hydroxyurea has never been used in malignant pertussis but is a well-known medication for oncologic and hematologic diseases such as acute myeloid leukemia or sickle cell anemia. Its effects in this setting are not well understood but the positive outcome in our patient supports the need for further studies
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