29 research outputs found

    Advanced European Re-Entry System Based on Inflatable Heat Shields: Detailed Design (EFESTO project)

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    The European Union H2020 EFESTO project is coordinated by DEIMOS Space with the end goals of improving the European TRL of Inflatable Heat Shields for re-entry vehicles (from 3 to 4/5) and paving the way towards further improvements (TRL 6 with a future In-Orbit Demonstrator, IOD). This paper presents the project objectives and the initial results of the detailed design of atmospheric entry missions based on the applications of advanced thermal protection systems implementing inflatable heat shields (flexible TPS and inflatable structures), according to aerothermodynamics constraints for future in-orbit demonstration. Placing the future IOD mission in the context of ongoing and future efforts in the European context is also one of the project goals. Two key applications, Mars Robotic Exploration and Reusable Small Launchers Upper Stages, have been identified. For the Mars Application, the robotic exploration mission class resulted in a 10 m diameter Hypersonic Inflatable Aerodynamic Decelerator (HIAD) class, combined with Supersonic Retro-Propulsion (SRP, activated about Mach 2.3) to deliver about 2800 kg of payload at MOLA +2 km. For the Earth Application, the VEGA upper stage (AVUM) has been selected as baseline case study. The current mission foresees a deorbiting from SSO orbit, a controlled entry phase (BC of about 30 kg/m2) and combines the use of a HIAD (4.5m diameter class) with parachutes and parafoil for Mid-Air-Capturing (MAR) with a helicopter. Beyond feasibility of the entry mission phase and system design with an inflated IAD, integration aspects have a key impact in the specific design solutions adopted, due to the nature of an inflatable heatshield. For both considered application cases feasible architectures are developed responding to the challenge of integrating the HIAD into the system in compliance with geometric and functional requirements. While the HIAD in folded state prior to inflation must fit in the available volume, it has limitations with respect to the density imposing a minimum cross section of the stowage volume. Simultaneously requirements with respect to the centre of gravity position during re-entry with an inflated HIAD must be respected for stability and controllability reasons. Other architectural considerations such as payload integration for the application on a launcher upper stage must be considered. Finally, heat loads constraints are considered for the trajectory and TPS deign choices due to important fluid-structure interactions. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 821801

    The Effect of Different Archwires on Initial Orthodontic Pain Perception: A Prospective Controlled Cohort Study

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    The early stages of orthodontic treatment are frequently associated with pain that can vary in intensity and duration, representing one of the main reasons for treatment discontinuation. Whilst the use of drugs is recognised as being effective to control orthodontic pain, there are no reliable data indicating the best first archwire for efficacy and minimum discomfort. A prospective controlled cohort study was conducted to compare the intensity and the characteristics of orthodontic pain during the first 15 days of treatment with 2 archwires. Fifty subjects were enrolled and divided into two groups: one received 0.012 inch stainless steel (SS) as the first archwire; the other, a 0.014 inch super-elastic nickel–titanium (Ni-Ti) archwire. Patients compiled a visual analogue scale to measure pain intensity over 15 days, a questionnaire for pain characteristics, the Somatosensory Amplification Scale and the State-Trait Anxiety Inventory to control the psychosocial component of pain. Dental casts were digitally analysed to evaluate the initial arch length discrepancy. In the first 3 days of treatment, the mean VAS values of the SS group were significantly lower than those of the Ni-Ti group (p < 0.05). No significant differences emerged between the groups concerning pain characteristics. The 0.012 inch SS archwire could be used at the beginning of orthodontic treatment to minimise pain perception and improve compliance

    Navicular tenosuspension with anterior tibialis tendon (Young procedure) associated to calcaneo-stop for the treatment of paediatric flexible flatfoot: clinical and ultrasound study

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    Background and aim of the work: Flexible flatfoot is one of the most common deformities in pediatric orthopaedics. Arthroeresis procedures are designed to correct this deformity. Among them, calcaneostop is a procedure with both biomechanical and proprioceptive properties. There could be other surgical procedure combined, such as a percutaneous Achilles tendon lengthening and the Gould tibialis posterior retension or Young tibialis anterior navicular tenosuspension. This study analyzed the clinical and sonographic results of 36 patients following flexible flatfoot surgical treatment with a calcaneo-stop arthroeresis combined with Achilles lengthening and a Young procedure. Methods: From March 2001 to August 2014, 36 patients (54 feet) were treated with calcaneo-stop arthroeresis, percutaneous Achilles tendon lengthening and Young\u2019s tenosuspension. The clinical assessment and a sonography of the anterior tibialis tendon (ATT) were performed in all patients. Results: The average follow-up was 7.4 years (range 8 months-14 years) with a satisfactory outcome in 51 feet (94.5%). No major and minor complications were observed. In four cases the calcaneo-stop was removed for pain and low tolerance of the patient. The AOFAS score and the talocalcaneal angle did not have statistically significant in case of ATT was or not still inserted in the navicular at the follow-up. Conclusions: The calcaneo-stop procedure is a simple, reliable and minimally invasive procedure for the treatment of pediatric flexible flatfoot. Although the indications for the Young tenosuspension as an isolated procedure is very narrow, it can still be an effective procedure when combined to calcaneo-stop. The key to appropriate utilization is a thorough understanding of the biomechanics of the foot function and a specific appreciation of the function of the ATT

    Differential effects of EPA vs. DHA on postprandial vascular function and the plasma oxylipin profile in men

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    Our objective was to investigate the impact of EPA versus DHA, on arterial stiffness and reactivity, and underlying mechanisms (with a focus on plasma oxylipins), in the postprandial state. In a 3-arm cross-over acute test meal trial men (n=26, 35-55y) at increased CVD risk, received a high fat (42.4g) test meal providing 4.16 g of EPA or DHA or control oil in random order. At 0 h and 4 h, blood samples were collected to quantify plasma fatty acids, LCn-3PUFAs derived oxylipins, nitrite and hydrogen sulfide and serum lipids and glucose. Vascular function was assessed using blood pressure, Reactive Hyperaemia Index (RHI), Pulse Wave Velocity and Augmentation Index (AIx). The DHA-rich oil significantly reduced AIx by 13% (P=0.047) with the decrease following EPA-rich oil intervention not reaching statistical significance. Both interventions increased EPA and DHA derived oxylipins in the acute postprandial state, with an (1.3 fold) increase in 19,20-DiHDPA evident after DHA intervention (P < 0.001). In conclusion, a single dose of DHA significantly improved postprandial arterial stiffness as assessed by AIx, which if sustained would be associated with a significant decrease in CVD risk. The observed increases in oxylipins provide a mechanistic insight for the AIx effect

    Acetabular Reconstruction with the Burch-Schneider Antiprotrusio Cage and Bulk Allografts: Minimum 10-Year Follow-Up Results

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    Reconstruction of severe pelvic bone loss is a challenging problem in hip revision surgery. Between January 1992 and December 2000, 97 hips with periprosthetic osteolysis underwent acetabular revision using bulk allografts and the Burch-Schneider antiprotrusio cage (APC). Twenty-nine patients (32 implants) died for unrelated causes without additional surgery. Sixty-five hips were available for clinical and radiographic assessment at an average follow-up of 14.6 years (range, 10.0 to 18.9 years). There were 16 male and 49 female patients, aged from 29 to 83 (median, 60 years), with Paprosky IIIA (27 cases) and IIIB (38 cases) acetabular bone defects. Nine cages required rerevision because of infection (3), aseptic loosening (5), and flange breakage (1). The average Harris hip score improved from 33.1 points preoperatively to 75.6 points at follow-up (P<0.001). Radiographically, graft incorporation and cage stability were detected in 48 and 52 hips, respectively. The cumulative survival rates at 18.9 years with removal for any reason or X-ray migration of the cage and aseptic or radiographic loosening as the end points were 80.0% and 84.6%, respectively. The use of the Burch-Schneider APC and massive allografts is an effective technique for the reconstructive treatment of extensive acetabular bone loss with long-lasting survival

    P.D.O. (Percutaneous Distal Osteotomy)

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    Controversies on surgical treatment of hallux valgus by minimally invasive percutaneous procedures: P.D.O. percutaneous distal osteotomy. Rationale, indications, sugical technique, clinical results and Literature review

    Evaluation of a Digital Protocol for Pre-Surgical Orthopedic Treatment of Cleft Lip and Palate in Newborn Patients: A Pilot Study

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    The aim of this study was to evaluate the accuracy, invasiveness and impact on clinical results of a digital oral impression protocol in the pre-surgical orthopedic treatment (PSOT) of newborn cleft lip and palate (CLP) patients undergoing primary alveolar surgical repair. Six patients were divided, according to impression technique used, into a digital (intraoral scanner (IOS)) and a non-digital (tray and putty (T&P)) group. Parents considered IOS impressions to be less invasive, compared to T&P impressions. The clinician that took all the impressions considered the IOS to be less stressful compared to the T&P method. In two T&P patients, the impression was repeated because some important anatomical details were missing, in one case due to patient regurgitation during the first attempt. No impression was repeated, and any adverse event was reported in the IOS group. There were no significant differences between these two protocols in pre-surgical alveolar gap reduction and surgical challenge. The study results indicate that this digital protocol can accelerate the production process of the passive molding plate with an instantaneous transmission of the digital impression to the dental lab, maintaining the same accuracy level and clinical outcomes of classical techniques and reducing the invasiveness of impression taking, avoiding any risk of impression material ingestion or inhalation

    2D vs. 3D Radiological Methods for Dental Age Determination around 18 Years: A Systematic Review

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    The age of a living human being can be determined by applying a number of dierent methods; the most diused are skeletal and dental methods, both principally based on X-rays examinations. This systematic review assesses the current evidence regarding the accuracy and reliability of Cone Beam Computed Tomography (CBCT) vs. Orthopantomography (OPG) in age determination. A computerized systematic literature search of studies published up to January 2020 was conducted without language restrictions in order to identify articles comparing CBCT vs. OPG in dental anatomy evaluation, articles evaluating the accuracy of dental methods for age estimation, both with CT andOPG exams, and articles comparing CBCT vs. OPG in terms of radiation dose. CBCT was found to be more accurate compared to OPG in dental anatomy evaluation. When analyzing young adults, an estimation error of two years is considered forensically acceptable. The radiation dose of a CBCT exam is higher compared to an OPG exam. However, the dierence is not as marked with small Fields Of View (FOV) and low-resolution protocols. Final conclusion was that a small FOV CBCT centered on the mandibular angle of a young patient is an accurate and safe method for dental age estimation around the age of 18

    Trasposizioni tendinee nei deficit di dorsiflessione del piede.

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    Surgical tendon transfer of posterior tibialis and anterior tibialis for neurologicaldrop foot is described. Rationale, indications, surgical techniqueand details, tips and tricks. Clinical results, literature reviewand experts' opinions

    Le osteotomie metatarsali e falangee nell'alluce rigido

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    Metattarsal and phalangeal osteotomies in the "joint-sparing" surgery of hallux rigidus-limitus. Literature review, surgical techniques and experts' opinions
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