Path planning for active SLAM based on deep reinforcement learning under unknown environments

Intelligent Service Robotics - Autonomous navigation in complex environment is an important requirement for the design of a robot. Active SLAM (simultaneous localization and mapping) combining,...     

Morphology of laryngeal cartilage of the nine‐banded armadillo (Dasypus novemcinctus) Linnaeus, 1758

Armadillos, Xenarthras representatives, known for adaptability to different ecosystems, own specific morphophysiological characteristics that are not known and deserve to be studied. The aim of this study was to describe the morphology of cartilage of the larynx of the nine‐banded armadillo (Dasypus novemcinctus). Five dead armadillos were donated by the Chico Mendes Institute of Biodiversity (ICMBio‐PI) to the Federal University of Piauí. The animals were fixed and dissected for removal of the larynx. The cartilages were identified and described, photodocumented, and schematized. Fragments with about 0.5 cm of each cartilage were collected and submitted to classical histology for Hematoxylin–Eosin coloring. The slides were assembled in enterlan and analyzed under a light microscope. The larynx of the armadillo (D. novemcinctus) is located in the mentonian region, ventral to the esophagus, and due to the total positioning of the tongue in the oral cavity, there is also a cranial cervical position in this species. The larynx has five cartilages, they are: a cricoid, a thyroid, an epiglottis, and two arytenoids. The corniculate process is present; however, the cuneiform process is absent. The epiglottis has a discrete bifurcation at its apex. In all cartilages epithelial variations are observed. The tissues are varied from squamoso stratified to cylindrical pseudostratified, with propria lamina rich in mucoserosas glands. With the exception of epiglottic cartilage, predominantly elastic, the rest are hyaline. The larynx of D. novemcinctus, although the same number of cartilages, differs morphologically and microscopically from the larynx of other species.     

Structural models of critical regions in old-type r.c. frames with smooth rebars

Structural assessment of existing reinforced concrete constructions under gravity loads and seismic actions has a high social and economical impact; actually in many European countries, most of the buildings dates back to 1960s and 1970s and cannot ensure satisfactory seismic response, since many areas have been later classified as seismic or since design has been carried out according to obsolete codes. These structures are generally reinforced with smooth bars that exhibit poor bond and need specific anchoring end details. In the present paper, some key aspects of structural models of smooth reinforcement for old-type r.c. frame analysis are reported. Results of experimental tests on smooth reinforcement and circular hook anchoring devices are also used to discuss some aspects of behavioural models of beam to column critical regions.     

Simple Method for the Design of Jet Grouted Umbrellas in Tunneling

Tunnel excavation in cohesionless soils implies the use of a temporary supporting structure prior to lining installation. This temporary structure has to couple safety and economy, and can be conveniently realized using ground improvement techniques (for instance, by creating an arch of partially overlapped subhorizontal jet grouted columns). The adoption of ground improvement techniques results in structures far from having a perfect shape because they are intrinsically affected by defects (in both geometrical and mechanical characteristics), and therefore their design may hide unforeseen risks. As a consequence, this is the typical case in which sophisticated numerical analyses may just give the illusion of being refined, if possible defects are not correctly taken into account. In this paper a simple yet rational analytical method for the design of a nonclosed tunnel supporting structure that may be of some help to this aim is presented. It is done with reference to a simple two-dimensional scheme. In the first part of the paper, a design chart of optimal shape and minimum structural thickness of the cross section of the supporting structure is shown. In the second part, an iterative procedure to verify the stability or to design the minimum structural thickness of an existing supporting structure with a predefined shape is described. This method, coupled with the analysis of structural demand, allows one in principle to plot design charts. This approach can easily take into account structural defects with a semiprobabilistic approach and therefore with a chosen risk level, which is of great help to the designer at least in a preliminary design stage. The proposed semiprobabilistic procedure is applied to the case of a temporary supporting structure realized by partially overlapped subhorizontal jet grouted columns, intrinsically affected by defects in diameter and position. The variability of these geometrical parameters was considered based on the large quantity of experimental evidence collected in field trials by the writers and published elsewhere.     

The Role of Endothelium in COVID-19

The 2019 novel coronavirus, known as severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) or coronavirus disease 2019 (COVID-19), is causing a global pandemic. The virus primarily affects the upper and lower respiratory tracts and raises the risk of a variety of non-pulmonary consequences, the most severe and possibly fatal of which are cardiovascular problems. Data show that almost one-third of the patients with a moderate or severe form of COVID-19 had preexisting cardiovascular comorbidities such as diabetes mellitus, obesity, hypertension, heart failure, or coronary artery disease. SARS-CoV2 causes hyper inflammation, hypoxia, apoptosis, and a renin–angiotensin system imbalance in a variety of cell types, primarily endothelial cells. Profound endothelial dysfunction associated with COVID-19 can be the cause of impaired organ perfusion that may generate acute myocardial injury, renal failure, and a procoagulant state resulting in thromboembolic events. We discuss the most recent results on the involvement of endothelial dysfunction in the pathogenesis of COVID-19 in patients with cardiometabolic diseases in this review. We also provide insights on treatments that may reduce the severity of this viral infection.     

An <Emphasis Type="Italic">ex post</Emphasis> criticism,based on stakeholders’ preferences,of a residential sector’s energy master plan: the case study of the Sicilian region

Energy master plans are important tools for an effective and sustainable land governance. On the other hand, the stakeholder role in setting priorities for planning energy interventions is dramatically increasing, also in the light of recently issued European directives. The priorities of energy-saving measures of the Sicilian energy and environmental master plan were originally established with the application of typical economic indicators (the cost of saved energy and the cost of avoided pollutant emissions). During the prioritization process, there was a minor contribution from stakeholders who were not directly involved in the priority-setting process but were only asked to express their opinions according to the in-force regulations. Based on more active stakeholder involvement in hierarchizing a given set of actions, as required by the recently issued directives, the University of Palermo, which participated in the development of this master plan, assessed an ex post evaluation of these established economy-based priorities, by means of the application of a multi-criteria decision analysis (MCDA) tool. The resulting changed priorities, which lead to a better policy allocation of the regional budget for energy efficiency in the building sector, confirm the preeminent role played by the stakeholders in the development of energy plans, further supported by a sensitivity analysis.     

Diabetes and Colorectal Cancer Risk: A New Look at Molecular Mechanisms and Potential Role of Novel Antidiabetic Agents

Epidemiological data have demonstrated a significant association between the presence of type 2 diabetes mellitus (T2DM) and the development of colorectal cancer (CRC). Chronic hyperglycemia, insulin resistance, oxidative stress, and inflammation, the processes inherent to T2DM, also play active roles in the onset and progression of CRC. Recently, small dense low-density lipoprotein (LDL) particles, a typical characteristic of diabetic dyslipidemia, emerged as another possible underlying link between T2DM and CRC. Growing evidence suggests that antidiabetic medications may have beneficial effects in CRC prevention. According to findings from a limited number of preclinical and clinical studies, glucagon-like peptide-1 receptor agonists (GLP-1RAs) could be a promising strategy in reducing the incidence of CRC in patients with diabetes. However, available findings are inconclusive, and further studies are required. In this review, novel evidence on molecular mechanisms linking T2DM with CRC development, progression, and survival will be discussed. In addition, the potential role of GLP-1RAs therapies in CRC prevention will also be evaluated.     

Processing and properties of resol and epoxy blends for resin transfer molding

Blends of epoxy and resol matrices for resin transfer molding (RTM) have been prepared and characterized with the double aim of improving the processability of resols and the fire resistance of epoxies. The reaction rate of the overall system is enhanced by the exothermic reaction between the epoxy and an aliphatic amine, which also promotes the resol reaction. In addition, the mechanical behavior of the resol is improved as the shear stress increases with the addition of epoxy resins. However, blending also produces a reduction of the intrinsic fire resistance of phenolic resins. The study demonstrated the feasibility of producing blends for matrices of composites processed by resin transfer molding. The recommended range for the epoxy content was determined through a balance of processability, fire resistance, and mechanical properties of the composites obtained. Moreover, the effects of fiber surface modifications were studied as a way to promote higher shear stresses in the epoxy-resol matrix composite without jeopardizing the fire resistance properties.     

Towards single atom analysis of biological structures.

Mapping single atoms in biological structures is now becoming within the reach of analytical electron microscopy. Electron energy-loss spectroscopy (EELS) in the field-emission scanning transmission electron microscope (STEM) provides a particularly high sensitivity for detecting the biologically important element, phosphorus. Imaging can be performed at low dose with dark-field STEM prior to analysis at high dose, so that structures of macromolecular assemblies can be correlated with the numbers of specific atoms that they contain. Measurements confirm theoretical predictions that single atom detection requires a nanometer-sized probe. Although phosphorus atoms may have moved several nanometers from their original positions by beam-induced structural degradation at the high required dose of approximately 10(9) e/nm2, damaged molecules are nevertheless stable enough to be analyzed at 1 or 2 nm resolution. Such analyses can only be achieved by means of spectrum-imaging with correction for specimen drift. Optimal strategies for mapping small numbers of phosphorus atoms have been investigated using well-characterized specimens of DNA plasmids and tobacco mosaic virus.