6,426 research outputs found
Very Low Cost Entropy Source Based on Chaotic Dynamics Retrofittable on Networked Devices to Prevent RNG Attacks
Good quality entropy sources are indispensable in most modern cryptographic
protocols. Unfortunately, many currently deployed networked devices do not
include them and may be vulnerable to Random Number Generator (RNG) attacks.
Since most of these systems allow firmware upgrades and have serial
communication facilities, the potential for retrofitting them with secure
hardware-based entropy sources exists. To this aim, very low-cost, robust, easy
to deploy solutions are required. Here, a retrofittable, sub 10$ entropy source
based on chaotic dynamics is illustrated, capable of a 32 kbit/s rate or more
and offering multiple serial communication options including USB, I2C, SPI or
USART. Operation is based on a loop built around the Analog to Digital
Converter (ADC) hosted on a standard microcontroller.Comment: 4 pages, 6 figures. Pre-print from conference proceedings; IEEE 21th
International Conference on Electronics, Circuits, and Systems (ICECS 2014),
pp. 175-178, Dec. 201
In-out versus out-in technique for ACL reconstruction. a prospective clinical and radiological comparison
Background: Several studies have recently shown better restoration of normal knee kinematics and improvement of rotator knee stability after reconstruction with higher femoral tunnel obliquity. The aim of this study is to evaluate tunnel obliquity, length, and posterior wall blowout in single-bundle anterior cruciate ligament (ACL) reconstruction, comparing the transtibial (TT) technique and the out–in (OI) technique. Materials and methods: Forty consecutive patients operated on for ACL reconstruction with hamstrings were randomly divided into two groups: group A underwent a TT technique, while group B underwent an OI technique. At mean follow-up of 10 months, clinical results and obliquity, length, and posterior wall blowout of femoral tunnels in sagittal and coronal planes using computed tomography (CT) scan were assessed. Results: In sagittal plane, femoral tunnel obliquity was 38.6 ± 10.2° in group A and 36.6 ± 11.8° in group B (p = 0.63). In coronal plane, femoral tunnel obliquity was 57.8 ± 5.8° in group A and 35.8 ± 8.2° in group B (p = 0.009). Mean tunnel length was 40.3 ± 1.2 mm in group A and 32.9 ± 2.3 mm in group B (p = 0.01). No cases of posterior wall compromise were observed in any patient of either group. Clinical results were not significantly different between the two groups. Conclusions: The OI technique provides greater obliquity of the femoral tunnel in coronal plane, along with satisfactory length of the tunnel and lack of posterior wall compromise. Level of evidence: II, prospective study
Extra-articular tenodesis combined with an anterior cruciate ligament reconstruction in acute anterior cruciate ligament tear in elite female football players
PURPOSE: The growing popularity of elite soccer among female participants has led to increased incidents of anterior cruciate ligament (ACL) ruptures. Many authors underline a positive glide after ACL reconstruction (ACLR), especially in women. In fact, an isolated intra-articular ACLR may be inadequate to control rotational instability after a combined injury of the ACL and the peripheral structures of the knee. Extra-articular procedures are sometimes used in primary cases displaying excessive antero-lateral rotatory instability. The purpose of this case series was to report subjective and objective outcomes after combined ACL and lateral extra-articular tenodesis (LET) with a minimum 4-year follow-up in a selected high-risk population of elite female football players.
METHODS: Between January 2007 and December 2010, 16 elite Italian female football players were included in the study. All patients underwent the same surgical technique: anatomical ACLR with autogenous semitendinosus and gracilis tendons. After the intra-articular reconstruction was performed, an additional extra-articular MacIntosh modified Coker-Arnold procedure was carried out. Patients were assessed pre- and post-operatively with the subjective and objective International Knee Documentation Committee (IKDC) evaluation form, Tegner activity scale (TAS) and Lysholm score. Joint laxity was assessed with KT-1000 by measuring the side-to-side (S/S) differences in displacement at manual maximum (mm) testing.
RESULTS: At a mean follow-up of 72.6 ± 8.1 months, two independent examiners reviewed all players. All of the patients had a fully recovered range of motion. Lachman test was negative in all patients (100 %). The evaluation of joint laxity and clinical evaluation showed a statistically significant improvement. No patients experienced complication or a re-rupture.
DISCUSSION: The rationale of combining extra-articular procedures with ACLR is to restrict the internal rotation of the reconstructed knee, taking advantage of its long lever arm and thus providing more stability in the rotational axis and preventing the ACL graft from undergoing further excessive strain.
CONCLUSIONS: The combination of an LET with ACLR in elite female football players demonstrated excellent results in terms of subjective scales, post-operative residual laxity and re-rupture rate with no complication, and a complete return to sport activity
Can the outside-in half-tunnel technique reduce femoral tunnel widening in anterior cruciate ligament reconstruction? A CT study
There are different techniques for drilling the femoral tunnel in the anterior cruciate ligament reconstruction (ACLR), but their influence in the bone tunnel enlargement in unknown. The purpose of this study was to compare two different surgical techniques for evaluating femoral tunnel enlargement in ACLR. The hypothesis was that tunnel placement using the outside-in technique leads to less tunnel enlargement compared to the transtibial technique.
METHODS:
Forty-four patients treated for ACLR between March 2013 and March 2014 were prospectively enrolled in this study. According to the surgical technique, subjects were assigned to Group A (Out-in) or Group B (Transtibial). All patients underwent CT examination in order to evaluate the femoral tunnel enlargement at four different levels. Moreover, all patients were evaluated with the Lachman test and pivot shift test, and the KT1000 arthrometer was used to measure the anterior laxity of the knee. A subjective evaluation was performed using the 2000 International Knee Documentation Committee Subjective Knee score, Lysholm knee score and Tegner activity scale. All patients were assessed after 24 months of follow-up.
RESULTS:
At the final follow-up, there were statistically significant differences (p 0.05).
CONCLUSIONS:
In ACLR with a suspension system, the outside-in technique leads to less enlargement of the femoral tunnel lower than the transtibial technique.
KEYWORDS:
Anterior cruciate ligament reconstruction; CT imaging; Drilling technique; Femoral tunnel enlargement
PMID: 28389757 DOI: 10.1007/s00590-017-1950-8
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Chest pain caused by multiple exostoses of the ribs: A case report and a review of literature
Abstract
The aim of this paper is to report an exceptional case of
multiple internal exostoses of the ribs in a young patient
affected by multiple hereditary exostoses (MHE) coming
to our observation for chest pain as the only symptom
of an intra-thoracic localization. A 16 years old patient
with familiar history of MHE came to our observation
complaining a left-sided chest pain. This pain had increased
in the last months with no correlation to a
traumatic event. The computed tomography (CT) scan
revealed the presence of three exostoses located on the
left third, fourth and sixth ribs, all protruding into the
thoracic cavity, directly in contact with visceral pleura.
Moreover, the apex of the one located on the sixth rib
revealed to be only 12 mm away from pericardium. Patient
underwent video-assisted thoracoscopy with an additional
4-cm mini toracotomy approach. At the last 1-year followup,
patient was very satisfied and no signs of recurrence or
major complication had occured. In conclusion, chest pain
could be the only symptom of an intra-thoracic exostoses
localization, possibly leading to serious complications.
Thoracic localization in MHE must be suspected when
patients complain chest pain. A chest CT scan is indicated
to confirm exostoses and to clarify relationship with surrounding
structures. Video-assisted thoracoscopic surgery
can be considered a valuable option for exostoses removal,
alone or in addiction to a mini-thoracotomy approach, in
order to reduce thoracotomy morbidity
Optimal Regulation Criteria for Building Heating System by Using Lumped Dynamic Models
Abstract Energy efficiency of buildings has gained an important role with respect to possible energy saving policy measures, mainly for space heating demand which represents the dominant energy end-use. The present contribution addresses the problem of estimating building heating energy consumptions by using numerical models able to simulate the dynamic interaction between the building and the heating system. A dynamic numerical code in the Engineering Equation Solver (EES) is developed to simulate both building and heating system and the influence of heating system regulation criteria on different parameters (mainly energy saving and internal comfort) is investigated in an optimization perspective
Partial tendon tear as unusual cause of trigger finger. a case report
We report a case of post-traumatic trigger finger due to a partial longitudinal tear of the flexor digitorum superficialis. The suspect came from the clinical history and the young age of the patient. It was successfully treated with tendon flap suture and pulley A1 release
Hey Maths ! Modèles formels et computationnels au service des Beatles
Cet article livre quelques réflexions sur les modèles formels et computationnels dans et pour les musiques populaires tout en mettant l’accent sur les chansons des Beatles. Après une présentation rapide des approches systématiques dans l’analyse de la forme, mais aussi des outils théoriques à la base de la représentation géométrique des structures et des processus musicaux (Tonnetz, constructions issues de la tradition analytique néo-riemannienne), les auteurs évoquent les questions que soulève l’analyse d’une collection de chansons des Beatles dès lors qu’on les envisage d’un point de vue formel et computationnel. En effet, si la forme et la structure des chansons des Beatles peuvent être étudiées sans recourir à des outils mathématiques, la modélisation informatique du processus de segmentation d’une pièce de musique, ainsi que les techniques issues du Music Information Retrieval, permettent d’approcher ces chansons d’un point de vue computationnel tout en posant la question de leur singularité par rapport à d’autres musiques elles aussi qualifiées de « populaires ».This article proposes some thoughts on formal and computational models in and for popular music by focusing on Beatles songs. After a brief presentation of some systematic approaches in the analysis of musical form and of some theoretical tools used in the geometric representation of musical structures and processes (the Tonnetz and other Neo-Riemannian constructions), the authors deal with the questions raised by the analysis of a collection of Beatles songs once they are studied either from a formal or a computational viewpoint. Even though the form and the structure of Beatles songs can be studied without using mathematical tools, the computer-aided modelling of the segmentation process of a musical piece, as well as the techniques belonging to the field of Music Information Retrieval, allow to give a quantitative, computational-oriented interpretation of Pop songs. At the same time, this approach opens the question of the singularity of this repertoire with respect to other popular music pieces
Single harvesting in the all-inside graft-link technique. is the graft length crucial for success? A biomechanical study
Background: The all-inside graft-link technique for anterior cruciate ligament reconstruction is performed with two cortical suspension devices with adjustable loops on both femur and tibia. This technique requires meticulous graft preparation. The aim of this study was to biomechanically test three different graft configurations resulting from differences in initial graft length. Materials and methods: Thirty bovine digital extensor tendons were arranged in three different ways: “half-quadrupled”, “tripled” and “quadrupled”. The final graft length was 65–75 mm. The specimens were fixed vertical to the loading axis of a tensile testing machine. After a static pre-conditioning of 50 N for 5 min, a load to failure test was performed and data regarding the ultimate failure load (UFL), the stiffness and mode of failure were recorded. Results: The evaluation of UFL showed a significant differences between group means as determined by one-way analysis of variance (F = 21.92, p = 0.002). Post hoc comparisons showed a significantly better UFL of “tripled” (p = 0.007) and “quadrupled” preparations (p = 0.014) compared to the “half-quadrupled” configuration, with no significant differences between “tripled” and “quadrupled” grafts (p = 0.061). No significant differences were found when evaluating the stiffness between the groups. Failure occurred by tendon slippage across the suture in all specimens. Conclusion: The “quadrupled” tendon achieved the best UFL, with even the “tripled” configuration having sufficient biomechanical characteristics to withstand the loads experienced during early rehabilitation. For this reason, with a total semitendinosus length of less than 260 mm it could be better to “triple” instead of “half-quadruple” it to achieve better performance of the graft
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