1,030 research outputs found

    The aspherical Cavicchioli-Hegenbarth-Repovš generalized Fibonacci groups

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    The Cavicchioli–Hegenbarth–Repovš generalized Fibonacci groups are defined by the presentations Gn (m, k) = 〈x 1, … , xn | xixi+m = xi+k (1 ⩽ i ⩽ n)〉. These cyclically presented groups generalize Conway's Fibonacci groups and the Sieradski groups. Building on a theorem of Bardakov and Vesnin we classify the aspherical presentations Gn (m, k). We determine when Gn (m, k) has infinite abelianization and provide sufficient conditions for Gn (m, k) to be perfect. We conjecture that these are also necessary conditions. Combined with our asphericity theorem, a proof of this conjecture would imply a classification of the finite Cavicchioli–Hegenbarth–Repovš groups

    Optimum Mechanical Design of Binary Actuators Based on Shape Memory Alloys

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    This chapter describes the optimum mechanical design of shape memory based actuators. The authors show how to exploit the Shape Memory Alloy (SMA) to design silent, compact and light binary actuators. Two simple mechanical models are considered to describe the SMA behaviour and design equations are provided for two classes of actuators. First SMA actuators are analyzed and designed on the basis of the backup element needed to recover the stroke. Second SMA actuators are improved by adding a compensator system to enhance the output mechanical response, especially in terms of available stroke. Useful design procedures are provided to help the engineer in the synthesis of SMA actuators. Starting from the design specifications, a step by step procedure is built to define the mechanical dimension of the SMA active elements, of the backup system and of the compensator

    Novel platinum agents and mesenchymal stromal cells for thoracic malignancies : state of the art and future perspectives

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    Introduction: Non-small cell lung cancer and malignant pleural mesothelioma represent two of the most intriguing and scrutinized thoracic malignancies, presenting interesting perspectives of experimental development and clinical applications. Areas covered: In advanced non-small cell lung cancer, molecular targeted therapy is the standard firstline treatment for patients with identified driver mutations; on the other hand, chemotherapy is the standard treatment for patients without EGFR mutations or ALK rearrangement or those with unknown mutation status. Once considered an ineffective therapy in pulmonary neoplasms, immunotherapy has been now established as one of the most promising therapeutic options. Mesenchymal stromal cells are able to migrate specifically toward solid neoplasms and their metastatic localizations when injected intravenously. This peculiar cancer tropism has opened up an emerging field to use them as vectors to deliver antineoplastic drugs for targeted therapies. Expert opinion: Molecular targeted therapy and immunotherapy are the new alternatives to standard chemotherapy. Mesenchymal stromal cells are a new promising tool in oncology and\u2014although not yet utilized in the clinical practice, we think they will represent another main tool for cancer therapy and will probably play a leading role in the field of nanovectors and molecular medicine

    Objective Selection Criteria between ALT and Radial Forearm Flap in Oral Soft Tissues Reconstruction

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    Different locoregional and free flaps were described for oral soft tissues reconstruction after oncological resections; however, free flaps remain the first choice. Among free flaps, the radial forearm flap (RFF) and the anterolateral thigh perforator flap (ALT) are preferred the most. The lack of standardization of the flap choice leaves the selection to the surgeon's experience. The purpose of our observational study is to provide an algorithm to support the flap choice for the reconstruction of oral soft tissues. Sixty patients with squamous cell carcinoma of oral soft tissues were enrolled in our study. All the patients underwent preoperative magnetic resonance imaging (MRI) to measure the three-dimensional size of the tumor. During the follow-up, the patients were evaluated by using the University of Washington-Quality of Life Questionnaire. The questionnaire score was better for small tumors and worse for large tumors in both functional and relational fields. We observed that most of the overlapping results were obtained for small defects and the choice of RFF, as well as for large defects and the use of ALT. We observed that in the preoperative time, it is possible to select which flap between radial forearm and ALT is more appropriate for oral soft tissues defects reconstruction, according to the size of the tumor evaluated by MRI. We propose a decisional algorithm that suggests the type of flap to use between ALT and RFF

    Semi-annual seasonal pattern of serum thyrotropin in adults

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    Circannual rhythmicity in thyroid-stimulating hormone (TSH) secretion is proposed, whereas evidences on seasonal peripheral thyroid hormones' fluctuation are contradictory. This study was designed to evaluate hypothalamic-pituitary-thyroid (HPT) seasonal secretion pattern using a big data approach. An observational, retrospective, big data trial was carried out, including all TSH measurements performed in a single laboratory between January 2010 and December 2017. A large dataset was created matching TSH data with patients' age, gender, environmental temperature exposure, and free triiodothyronine (fT3) and free thyroxine (fT4) when available. The trend and seasonal distributions were analysed using autoregressive integrated moving average models. A total of 1,506,495 data were included in the final database with patients mean age of 59.00 +/- 18.44 years. The mean TSH serum levels were 2.08 +/- 1.57 microIU/mL, showing a seasonal distribution with higher levels in summer and winter seasons, independently from age, gender and environmental temperatures. Neither fT3 nor fT4 showed a seasonal trend. TSH seasonal changes occurred independently from peripheral thyroid hormone variations, gender, age and environmental temperatures. Although seasonal TSH fluctuation could represent a residual ancestral mechanism to maintain HPT homeostasis, the underlying physiological mechanism remains unclear and specific studies are needed to clarify its impacting role in humans

    Obturator nerve split for gracilis free-flap double reinnervation in facial paralysis

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    The use of a double-powered free muscle transfer for facial reanimation has been reported by several authors with different types of nerve coaptation. A new nerve coaptation strategy is presented herein. We performed a 1-stage double-powered free gracilis muscle flap transfer in a patient with long-standing facial paralysis by splitting the obturator nerve and anastomosing the 2 free ends to the contralateral facial nerve (through a sural graft) and to the masseteric nerve. Voluntary movement of the transferred muscle with teeth clenching was observed at 6 months after the operation and a symmetric smile with bilateral elevation of the mouth angle at 10 months. Our limited experience suggests that in case of a large cross-section of the obturator nerve, the latter can be split and sutured to the ipsilateral masseteric nerve and to the contralateral facial nerve with a sural graft by double end-to-end anastomosis

    The “hitchhiker’s guide to the galaxy” of endothelial dysfunction markers in human fertility

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    Endothelial dysfunction is an early event in the pathogenesis of atherosclerosis and represents the first step in the pathogenesis of cardiovascular diseases. The evaluation of endothelial health is fundamental in clinical practice and several direct and indirect markers have been suggested so far to identify any alterations in endothelial homeostasis. Alongside the known endothelial role on vascular health, several pieces of evidence have demonstrated that proper endothelial functioning plays a key role in human fertility and reproduction. Therefore, this stateof‐the‐art review updates the endothelial health markers discriminating between those available for clinical practice or for research purposes and their application in human fertility. Moreover, new molecules potentially helpful to clarify the link between endothelial and reproductive health are evaluated herein
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