Asphericity of symmetric presentations

Using the notion of relative presentation due to Bogley and Pride, we give a new proof of a theorem of Prishchepov on the asphericity of certain symmetric presentations of groups. Then we obtain further results and applications to topology of low-dimensional manifolds

The character variety of one relator groups

We consider some families of one relator groups arising as fundamental groups of 3-dimensional manifolds, and calculate their character varieties in SL(2, C). Then we give simple geometrical descriptions of such varieties, and determine the number of their irreducible components. Our paper relates to the work of Baker-Petersen, Qazaqzeh and Morales-Marcen on the character variety of certain classes of one relator groups, but we use different methods based on the concept of palindrome presentations of given groups

The aspherical Cavicchioli-Hegenbarth-Repovš generalized Fibonacci groups

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

Topology of compact space forms from Platonic solids. I.

AbstractThe problem of classifying, up to isometry, the orientable 3-manifolds that arise by identifying the faces of a Platonic solid was completely solved in a nice paper of Everitt [B. Everitt, 3-manifolds from Platonic solids, Topology Appl. 138 (2004) 253–263]. His work completes the classification begun by Best [L.A. Best, On torsion-free discrete subgroups of PSL2(C) with compact orbit space, Canad. J. Math. 23 (1971) 451–460], Lorimer [P.J. Lorimer, Four dodecahedral spaces, Pacific J. Math. 156 (2) (1992) 329–335], Prok [I. Prok, Classification of dodecahedral space forms, Beiträge Algebra Geom. 39 (2) (1998) 497–515], and Richardson and Rubinstein [J. Richardson, J.H. Rubinstein, Hyperbolic manifolds from a regular polyhedron, Preprint]. In this paper we investigate the topology of closed orientable 3-manifolds from Platonic solids. Here we completely recognize those manifolds in the spherical and Euclidean cases, and state topological properties for many of them in the hyperbolic case. The proofs of the latter will appear in a forthcoming paper

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

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

Exploitation of drainage water heat: A novel solution experimented at the Brenner Base Tunnel

Deep tunnels in permeable fractured rock-masses and under high piezometric levels can drain notable volumes of warm water, which are collected under gravity in specific conduits towards the portals, where heat can be exploited. The utilization of this energy source is generally narrowed by the limited presence of end-users near the portals, while other promising heating and cooling needs can be found directly along the tunnel length. The work presents the design, construction and installation of a geothermal system prototype exploiting the drainage water heat directly inside the tunnel. The prototype was named Smart Flowing due to the peculiarity of its heat exchange process. The system was realized and installed inside the exploratory tunnel of the Brenner Base Tunnel, near the border between Italy and Austria. The Smart Flowing modules were built outside and later moved inside the tunnel, where they were placed and assembled concurrently to the advancement of the Tunnel Boring Machine. A design procedure was proposed and validated against a testing and monitoring campaign. The data from the experimental activity confirmed that the drainage water flow guarantees long-term stabilization of circulating water temperature and fast heat recovery afterwards, thus securing the considerable power and performance values of a water-water heat pump connected to the system. A sensitivity analysis allowed the reproduction of different working scenarios, in order to generalize the application of Smart Flowing beyond the specific installation context

Stop using the flotation technique and start weighing salbutamol pressurised metered-dose inhalers without dose counters.

Salbutamol pressurised metered-dose inhalers (pMDIs) are not equipped with dose counters outside the USA. The aim of this study was to describe a simple reproducible method for determining the number of doses remaining in a pMDI based on scale weight. With a laboratory scale, the mean weight of the canisters was 28.61 ± 0.10 g after priming and 14.84 ± 0.23 g after 200 puffs. Similar results were obtained with two common digital scales. We recommend weighing salbutamol canisters on a common digital scale, and replacing an old pMDI with a new one when the weight falls to ≤15 g

Carinal resection

Carinal resection is defined as the resection of tracheo-bronchial bifurcation, with or without lung parenchyma resection. It represents one of the most challenging areas of airway resection and reconstruction, basically due to the variability in the location and extent of the lesions. Main indications for this procedure are primary tumours of the carina or the distal trachea or, more frequently, bronchogenic carcinoma with carinal involvement. Very different approaches and reconstruction techniques have been experimentally and clinically described in the last 50 years, with some corner stone procedures in the history of modern thoracic surgery. Despite many technical and oncological difficulties encountered in this field, encouraging results have been reported in recent series, in particular an excellent 5-year survival rate of 50% in pN0 patients suffering form carinal infiltration form lung cancer. Several aspects of the multimodality approach to neoplastic carinal involvement still remain debatable like radio-chemotherapeutic approach instead of the extremely rare left carinal pneumonectomy as well as the role of induction treatments before embarking in such demanding procedures, according to the \uadpathological nodal status