5,711 research outputs found
High performances monolithic CMOS detectors for space applications
During the last 10 years, research about CMOS image sensors (also called APS -Active Pixel Sensors) has been intensively carried out, in order to offer an alternative to CCDs as image sensors. This is particularly the case for space applications as CMOS image sensors feature characteristics which are obviously of interest for flight hardware: parallel or semi-parallel architecture, on chip control and processing electronics, low power dissipation, high level ofradiation tolerance... Many image sensor companies, institutes and laboratories have demonstrated the compatibility of CMOS image sensors with consumer applications: micro-cameras, video-conferencing, digital-still cameras. And recent designs have shown that APS is getting closer to the CCD in terms ofperformance level. However, the large majority ofthe existing products do not offer the specific features which are required for many space applications. ASTRI1JM and SUPAERO/CIMI have decided to work together in view of developing CMOS image sensors dedicated to space business. After a brief presentation of the team organisation for space image sensor design and production, the latest results of a high performances 512x512 pixels CMOS device characterisation are presented with emphasis on the achieved electro-optical performance. Finally, the on going and short-term coming activities of the team are discussed
Development of high-performances monolithic CMOS detectors for space applications
This paper describes the development of a 750x750 pixels CMOS image sensor for star tracker applications. A first
demonstrator of such a star tracker called SSM star tracker built around a 512x512 detector has been recently developed and proves the feasibility of such instrument. In order to take fully advantage of the CMOS image sensor step, the 750x750 device called SSM CMOS detector which will take part of the final star tracker, can be considered as a major technical breakthrough that gives a decisive advantage in terms of on satellite implementation cost and flexibility (sensor mass and power consumption minimisation, electronics and architecture flexibility). Indeed, built using the 0.5ÎĽm Alcatel Microelectronics standard CMOS technology, the SSM CMOS detector will feature on-chip temperature sensor and on-chip sequencer. In order to evaluate the radiation tolerance of such manufacturing technology, a radiation campaign that contains studies of total dose and latch-up effects has been led on a specific test vehicle
Improved Injection Technique of Ethanol for Morton's Neuroma
Background:Morton's neuroma is a common cause of forefoot pain. Various conservative methods (injections of various pharmacologic agents) have been published with an outcome of 6%-75% success rate (free of pain in daily life) per injection. The aim of the present study was to assess the outcome of an improved localization technique, a higher dosage, and a higher percentage of ethanol.Methods:Using fluoroscopic and electroneurographic guidance, 2.5 mL of 70% ethanol were injected into 33 feet with a magnetic resonance imaging (MRI)-verified neuroma. We evaluated patients at up to 5-year follow-up.Results:A "success rate" of more than 82% per single injection (defined as free of pain in daily life) was achieved and no recurrence was seen over 5 years. All scores (visual analog scale; Short Form-36 subscales, American Orthopaedic Foot & Ankle Society ankle-hindfoot score) showed significant improvement (P < .0001). Mean 1.2 injections were necessary. No significant side effects were seen. However, some mild pain persisted in some patients who participated in sports.Conclusion:The injection of 2.5 mL of 70% ethanol under fluoroscopic and electroneurographic guidance was a safe method for the treatment of MRI-verified Morton's neuromas. Combining the effect of a higher percentage of alcohol and a higher dosage and an improved localization technique resulted in a high rate of patients without pain
Lipoaspirate processing for the treatment of knee osteoarthritis: a review of clinical evidences
The autologous lipoaspirate processing allows to obtain a tissue product to be transplanted for regenerative purposes in multiple pathological sites, such as the knee joint affected by osteoarthritic disease. Recently, multiple protocols and devices have been designed for lipoaspirate processing. These protocols and devices do not use enzymatic digestion and respect the principles of the so-called "minimal manipulation in a closed system". In this study, we performed a systematic review of the literature to identify studies in which osteoarthritis was treated by minimally manipulated intra-articular SVF injection and assessment of therapeutic response was reported. All bias scores were analyzed based on the Coleman methodology score modified by Kon et al. [27] and a subsequent linear classification system of articles was proposed. We identified 12 clinical trials in which clinical evaluations were performed inconsistently using different scales of analysis. All studies reported a significant decrease in the patient's symptomatic discomfort, with improvement in joint function and reduction in pain. Most studies do not reach a high-quality level on the linear scale based on the Coleman-Kon scores. Although the treatment of osteoarthritis of the knee with regenerative methods is undoubtedly of interest, being aimed at healing the disease, this study highlights that the trials are numerically limited, and qualitatively not optimal according to the Coleman-Kon score. Reasonably, greater standardization of devices protocols will be desirable in the future. The high clinical potential offered by these methods could be optimized for all patients
Fourth generation head fracture in ceramic-on-polyethylene bearing after hip revision surgery: a case report
Fourth generation ceramic bearings (BIOLOX delta, CeramTec AG; Phlochingen, Germany) were developed to reduce wear debris and improve fracture resistance. A case of a fourth generation head fracture in ceramic-on-polyethylene (COP) coupling after hip revision surgery is reported. A 58-year-old man was admitted to our department for increasing hip pain following a direct trauma which occurred during skiing activity 4 months before. Six years earlier, he had undergone a right cementless revision surgery with a 36-mm BIOLOX delta femoral head on polyethylene liner for metallosis and foreign body reaction after primary total hip replacement for hip osteoarthritis. At admission, radiological evaluation revealed a fracture of ceramic femoral head requiring a new revision surgery. Extensive synovectomy, lavage and capsulectomy were performed. Both acetabular cup and femoral stem were well fixed with no damage of trunnion, and therefore they were retained. A 36-mm internal diameter polyethylene acetabular liner was inserted along a 36-mm BIOLOX delta head with a BioBall adapter XL. The postoperative course was uncomplicated. At 1-year follow-up, the patient had a complete functional recovery. To our knowledge, BIOLOX delta ceramic femoral head fracture after COP hip revision surgery has not been previously reported
Release of Gentamicin and Vancomycin from Preformed Spacers in Infected Total Hip Arthroplasties: Measurement of Concentrations and Inhibitory Activity in Patients’ Drainage Fluids and Serum
Gentamicin (G) and vancomycin (V) concentrations in drainage fluids obtained from patients during the first 24 hours after implantation of antibiotic-loaded polymethylmethacrylate (PMMA) spacers in two-stage revision of infected total hip arthroplasty were studied. The inhibitory activity of drainage fluids against different multiresistant clinical isolates was investigated as well. Seven hips were treated by implantation of industrial G-loaded spacers. Vancomycin was added by manually mixing with PMMA bone cement. Serum and drainage fluid samples were collected 1, 4, and 24 hours after spacer implantation. Antibiotics concentrations and drains bactericidal titer of combination were determined against multiresistant staphylococcal strains. The release of G and V from PMMA cement at the site of infection was prompt and effective. Serum levels were below the limit of detection. The local release kinetics of G and V from PMMA cement was similar, exerting a pronounced, combined inhibitory effect in the implant site. The inhibitory activity of drainage fluids showed substantial intersubject variability related to antibiotic concentrations and differed according to the pathogens tested. Gentamicin and vancomycin were released from temporary hip spacers at bactericidal concentrations, and their use in combination exerted strong inhibition against methicillin-resistant S. aureus and Coagulase Negative Staphylococci strains
Central metatarsal fractures: a review and current concepts
Central metatarsal fractures (CMF) are common injuries. More frequently fractures are those of the fifth metatarsal, followed by CMF and therefore by the first metatarsal. Third metatarsal is injured most frequently than the others and up to 63% is associated with second or fourth metatarsal fractures and up to 28% with both. Anatomy and metatarsal kinematics merits attention due to its influence on function, injuries and treatment options. Diagnosis is based on the history of trauma and clinical examination, relating with instrumental exams. Fractures with less than 10\ub0 of angulation and 3-4 mm of translation in any plane are typically treated conservatively, while operative treatment is generally reserved for fractures out if these values. Intramedullary fixation with K-wires seem to be the most common and valid surgical treatment in simple fractures. Spiral fractures should be treated by interfragmentary screws, which positioning may result difficult due to the adjacent metatarsals. Therefore, an alternative approach is an osteosynthesis with a dorsal plate. Multiple metatarsal fractures often occur in the contiguous bones, so clinicians will also have to carefully inspect metatarsals and adjacent joints such as Lisfranc articulation. The clinical and functional outcomes are often influenced by the pattern of fractures and patient conditions and are reported in the literature up to 39% of poor results
Total ankle replacement in young patients
High physical demand and younger age are currently considered contraindications for total ankle replacement. The number of Total Ankle Replacements (TAR) is widespread increasing and indications are expanding thanks to a steady improvement in prosthetic designs and better outcome. Commentary of the literature: in 1999 a study of 100 uncemented STAR\u2122 (Waldemar-Link, Hamburg, Germany) prostheses showed a survival rate of 75% at 6.8 years in patients under 50 years old. Other studies (es, Barg et Al.) shows the risk of failure age-related in young patients compared to older group. A report of 780 TAR from the Swedish Ankle Register showed patients with primary or post-traumatic osteoarthritis under 60 years of age to have a 1.8 higher chance of revision compared to older patients. Discussion: ankle replacement has been traditionally reserved for patients older 50 years old and with low physical demand. Contrariwise this belief, TAR have already been used with a wide range of ages, sometimes even patients younger than 30 years old. Most of the "negative" score and results showed before are related to "second-generation" prosthetic designs, while recent studies used a "third-generation" prosthetic design. Conclusions: recent evidences showed better clinical results and higher satisfaction in people under the age of 50 compared to ankle arthrodesis with comparable rate of complications and survivorship. Younger people will have however a higher rate of reoperation but in the meantime, they will prevent progressive degeneration of adjacent joints
Smart CMOS image sensor for lightning detection and imaging
We present a CMOS image sensor dedicated to lightning detection and imaging. The detector has been designed to evaluate the potentiality of an on-chip lightning detection solution based on a smart sensor. This evaluation is performed in the frame of the predevelopment phase of the lightning detector that will be implemented in the Meteosat Third Generation Imager satellite for the European Space Agency. The lightning detection process is performed by a smart detector combining an in-pixel frame-to-frame difference comparison with an adjustable threshold and on-chip digital processing allowing an efficient localization of a faint lightning pulse on the entire large format array at a frequency of 1 kHz. A CMOS prototype sensor with a 256Ă—256 pixel array and a 60 ÎĽm pixel pitch has been fabricated using a 0.35 ÎĽm 2P 5M technology and tested to validate the selected detection approach
Thirty-Day Mortality in COVID-19 Positive Patients With Hip Fractures: A Case-Series and Literature Review
Introduction: The novel coronavirus has spread rapidly around the world with particularly high mortality in the elderly. Care and nursing homes have become the sites of greatest concentration of cases. We intended to review 30-day mortality of COVID-19 patients with hip fractures. This is relevant given the disease impact in this age group.Methods: Medline and Embase databases were searched for relevant studies linked to mortality and morbidity in COVID-19 patients who have undergone non-elective hip surgeries using the keywords "COVID-19"OR "SARS-cov-2"OR "Coronavirus Infections"; AND "Surgery"OR "Hip"OR "Fracture"OR "Orthopedics." We included all patients with hip fractures, but excluded pathological fractures and other non-traumatic hip pathologies. Four-hundred and eighty-one articles were identified for screening, in addition to an unpublished case-series of 67 patients that have 3 cases turned positive for COVID 19, yielding a total of 50patients for the final review.Results: The study included 4 articles published until May 9th 2020 and a case-series: 26(52%) patients were females; the median age was 86years; hypertension(53.6%), diabetes mellitus type II(28.6%), and coronary artery heart disease(25%) were the most common comorbidities; 34(68%) patients had intertrochanteric hip fracture and 16(32%) patients had femoral neck fractures; 22(59.5%) patients underwent cephalomedullary nail fixation, 12(32.4%) patients had hemiarthroplasty, and for 3(8.1%) patients, the type of surgery was not documented; 20(40%) patients died(12patients died before the surgery and 8died after surgery at a median time of 3days), 29(76.3%) patients had an unremarkable course throughout hospitalization and were discharged including 1(2.6%) patient managed non-operatively, and 1(2.6%) patient was admitted to the ICU after the surgery but eventually discharged.Conclusion: COVID-19 infected elderly patients have a higher 30-days mortality rate compared to non-COVID-19 infected cases. Further studies are warranted to look at the morbidity and mortality rates in COVID-19 positive patients with hip fractures and to investigate how these outcomes can be improved.Level of evidence: Level IV
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