Overall visibility plays a key role in the safety of pedestrians. Despite its importance, verifying the right provisioning of sufficient available sight distances among pedestrians and vulnerable ...road users (VRUs) is not a prevalent practice. On top of that, the pursuit for more sustainable modes of transportation has promoted the establishment of different shared mobility services which are prone to increase walking and, thus, the number of pedestrians and other VRUs in urban settings. With the intention of verifying how car-centered designs perform for non-motorized users, a 3D procedure that evaluates the visibility of pedestrians and other users is presented and applied to specific cases in Madrid, Spain. The proposed solution employs virtual trajectories of pedestrians with mobility impairments and without them, cyclists, and personal transportation device riders. Their visibility was assessed around the functional area of urban intersections, including zones where possible jaywalking practices might occur. The evaluation was performed three-dimensionally, making use of LiDAR data, GIS tools, and 3D objects. Results show the impact of street furniture location on visibility, the distinctive influence of vegetation on the lines of sight of each observer, and how design parameters that were intended to improve motorized traffic could affect VRU.
Road safety is key to sustainable mobility. Rapid technological advances have allowed several road safety-related analyses, previously performed in situ, to be conducted virtually. These virtual ...analyses benefit understanding of how roads operate and how users perceive them. Additionally, they facilitate the assessment of several parameters that are fundamental to road design and operation. The available sight distance (ASD) is one of these parameters that, if not provided adequately, could alter the proper functioning of roads. This study presents a framework to assess the impact of certain features on visibility. First, the ASD is estimated using a geographic information system (GIS)-based procedure with LiDAR-derived three-dimensional (3D) models. Afterward, obstructions are detected and categorized. If the obstruction cannot be removed, their redesign or relocation is simulated to re-run the analysis. These simulations are performed using 3D city objects, and their results are statistically evaluated, providing evidence as to their effects on visibility. The results proved that the procedure helped achieve the efficient use of roadside space, while including safety concerns. Additionally, this study reflects the need for more inspections on the impact of on-street parking on drivers’ fields of view.
Adequate sight distances are crucial parameters ruling the design of roads and riding facilities. LiDAR-retrieved data have proved to serve many transportation applications by creating updated and ...accurate representations of the road environment. As a result, many sight distance evaluation methodologies use LiDAR delivered point clouds to carry out visibility analyses. However, current approaches are mainly focused on motorized users along highways and streets, and most of those methodologies are carried out directly on the point cloud, which does not allow the evaluation or relocation of visual obstructions. This study presents a visibility-based procedure intended to assess the circulation of pedestrians and riders at urban intersections. For this purpose, first, the required sight distances of all users along the intersection are obtained. Second, the conflicts between vulnerable road users are evaluated, considering the type of control present at the intersection. The available sight distances are then obtained using a GIS-based method that employs 3D road models derived from the LiDAR retrieved data. Finally, after a comparison between the required and the available visibility, an evaluation determines which user sees a larger percentage of the intersection. This approach facilitates evaluating the impact that vegetation, traffic, and/or furniture elements could have on visibility and serve as an urban design aid tool. Results show that the proposed method offers valuable insights into the distributions of visibility among intersecting users and into the quantifications of the effect of specific adjacent traffic. Moreover, this procedure stands as a useful and flexible approach that allows the evaluation of both cyclists and e-scooter riders in different road facilities and positionings.
Existing roads require periodic evaluation in order to ensure safe transportation. Estimations of the available sight distance (ASD) are fundamental to make sure motorists have sufficient visibility ...to perform basic driving tasks. Mobile LiDAR Systems (MLS) can provide these evaluations with accurate three-dimensional models of the road and surroundings. Similarly, Geographic Information System (GIS) tools have been employed to obtain ASD. Due to the fact that widespread GIS formats used to store digital surface models handle elevation as an attribute of location, the presented methodology has separated the representation of ground and aboveground elements. The road geometry and surrounding ground are stored in digital terrain models (DTM). Correspondingly, abutting vegetation, manmade structures, road assets and other roadside elements are stored in 3D objects and placed on top of the DTM. Both the DTM and 3D objects are accurately obtained from a denoised and classified LiDAR point cloud. Based on the consideration that roadside utilities and most manmade structures are well-defined geometric elements, some visual obstructions are extracted and/or replaced with 3D objects from online warehouses. Different evaluations carried out with this method highlight the tradeoff between the accuracy of the estimations, performance and geometric complexity as well as the benefits of the individual consideration of road assets.
This systematic review aims to analyze the effect of the local application of statins in the regeneration of non-periodontal bone defects. A systematic study was conducted with the Pubmed/Medline, ...Embase, Cochrane Library and Scielo databases for in vivo animal studies published up to and including February 2019. Fifteen articles were included in the analysis. The local application of the drug increased the percentage of new bone formation, bone density, bone healing, bone morphogenetic protein 2, vascular endothelial growth factor, progenitor endothelial cells and osteocalcin. Meta-analyses showed a statistically significant increase in the percentage of new bone formation when animals were treated with local statins, in contrast to the no introduction of filling material or the introduction of polylactic acid, both in an early (4–6 weeks) and in a late period (12 weeks) (mean difference 39.5%, 95% confidence interval: 22.2–56.9, p <0.001; and mean difference 43.3%, 95% confidence interval: 33.6–52.9, p < 0.001, respectively). Basing on the animal model, the local application of statins promotes the healing of critical bone size defects due to its apparent osteogenic and angiogenic effects. However, given the few studies and their heterogenicity, the results should be taken cautiously, and further pilot studies are necessary, with radiological and histological evaluations to translate these results to humans and establish statins’ effect.
The aim of the present investigation was to evaluate the literature recurrence of peripheral giant cell granuloma and pyogenic granuloma associated with dental implants. It's important to know the ...characteristics present in these lesions and possible effects on the prognosis of dental implants.
An electronic search without time restrictions was done in the databases: PubMed/Medline. With the keywords "Granuloma" OR "Granuloma, Giant Cell" OR "peripheral giant cell" OR "Granuloma, Pyogenic" AND "Dental implants" OR "Oral implants".
After applying the inclusion and exclusion criteria, a total of 20 articles were included, which reported 32 lesions (10 pyogenic granulomas, 21 peripheral giant cell granulomas and one peripheral giant cell granuloma combined with peripheral ossifying fibroma, all associated with implants). According to our review, these lesions are more frequent in males and in the posterior region of the mandible. Both excision and curettage of the lesion, compared to only excision, presented similar recurrences (40%). Explantation of the implant was performed in 41% of cases without additional recurrences. The results are not statistically significant when comparing one lesion to the other in terms of explantation (p = 0.97), recurrence (p = 0.57) or bone loss (p = 0.67).
The main therapeutic approach is tissue excision. The lesions show a high recurrence rate (34.4%), which often requires explantation of the associated implant. This recurrence rate is not affected by curettage after excision.
Road elements are predominantly designed to safely accommodate motorized users. Urban roads and streets, unlike highways, contain very dissimilar users and might have higher points of conflict. ...Nowadays, due to the increasing use of vehicle sharing systems, personal transportation devices and bicycle-friendly policies, some urban streets have had to adapt to distinct users with different levels of vulnerability. Given the interest in increasing the use of alternative transportation methods, it is of great importance to make sure these car-centered designed roads provide securely for all users. In order to create a safe environment for these unalike users, common measures such as reducing speed limits, traffic calming interventions and modifications to the road geometry have been taken in several urban areas. In this regard, taking into account the key role that proper available sight distance plays in road safety, the visibility of an urban roundabout located in Madrid, Spain was evaluated. This analysis was performed considering the observers to be pedestrians, cyclists and electric scooter riders. In addition to the estimation of their crossing and stopping sight distances, their reciprocal visibility with drivers was assessed. Nowadays there are different ways of obtaining up-to-date information of the road scene and cycle lanes with sufficient accuracy and detail, hence it is possible to easily perform offsite analyses of distinct road parameters. Here, the virtual verification of sufficient stopping and intersection sight distances was performed utilizing a LiDAR derived digital terrain model and 3-D geometries. These evaluations were performed with the objective of identifying potential risk locations for these vulnerable users and the proposal of measures that could improve their safety.
Sight distance estimations are significant components of road safety analyses. Drivers ought to have enough available sight distance (ASD) in order to safely perform basic driving maneuvers. When not ...performed in situ, estimating ASD on existing roads normally requires up-to-date representations of the roads’ geometric properties as well as the execution of roadway design related tasks and geospatial analysis operations; hence, several software products are needed to carry out these calculations throughout their entire workflow. Nowadays, LiDAR based Mobile Mapping Systems (MMS) have been intensively put into use to gather data needed to accomplish many transportation applications. In spite of their many benefits, MMS produce fair volumes of point cloud data which add some complexity to the processing stage in terms of software, computational requirements and interoperability. This paper analyses software capabilities, in terms of suitability and performance, of computer programs capable of LiDAR data processing tasks. The main goal of this evaluation is to gauge their aptness to deliver data needed to perform ASD estimations. To accomplish this, a thorough review of available literature on sight distance analyses was conducted to get a depiction of frequently demanded software tasks and deliverables and based on that, clouds with different amount of points were processed with a variety of software solutions in order to test their appropriateness for the purpose, from early stages of the workflow to final calculations. This research highlights how the truly potential of LiDAR data for performing highway safety related analyses relies heavily upon the usage of efficient and powerful software tools.
Introducción: el intervalo QTc prolongado predispone a arritmias graves. Diversos medicamentos, entre ellos los antirretrovirales, pueden prolongarlo. Los objetivos fueron determinar las ...características demográficas, clínicas y la frecuencia del intervalo QTc prolongado en pacientes con VIH. Métodos: estudio observacional, prospectivo, con grupo control. Se incluyeron varones y mujeres, mayores de 18 años, portadores de infección por VIH, que acudieron al Hospital Nacional (Itauguá, Paraguay) durante 2020. Actuaron como grupo control los estudiantes de Medicina. Se excluyeron todos los sujetos que no dieron su consentimiento y los portadores de arritmias. Se midieron variables demográficas, clínicas, laboratoriales y electrocardiograma de 12 canales en reposo. El estudio contó con la aprobación del Comité de Ética de la Universidad Privada del Este (Paraguay). Resultados: ingresaron al estudio 39 pacientes con VIH y 39 controles sanos. La edad media de los casos fue 37 ± 11 años, siendo 59% del sexo masculino. La comorbilidad más frecuente en los casos fue la obesidad (7,6%). Los valores medios de urea, creatinina, K, Ca y Mg en los casos se hallaban en rango normal. Se detectó 18% de QTc prolongado en casos y 0% en los controles. Estos sujetos con alteración electrocardiográfica se hallaban todos en tratamiento antirretroviral y antibiótico múltiple de conocida asociación con QTc prolongado. Conclusión: la frecuencia de QTc prolongado en pacientes con VIH fue del 18% y en controles sanos fue del 0%. Se recomienda el control periódico del electrocardiograma en pacientes con VIH en tratamiento con fármacos que prolongan el intervalo QT.
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