Upper Second Molar Distalization with Clear Aligners: A Finite Element Study

Among orthodontists and scientists, in the last years, upper molar distalization has been a debated topic in the orthodontic aligner field. However, despite that few clinical studies have been published, no insights on aligners' biomechanics regarding this movement are available. The aim of this study was to assess, through finite element analysis, the force system resulting in the upper arch during second maxillary molar distalization with clear aligners and variable attachments settings. The average tooth distalization was found to be 0.029, with buccal flaring of the upper incisors in all attachment configurations. The mesial deformation of the aligner was registered to be 0.2 mm on average. Different pressure areas on the interface between aligners and upper molars were registered, with the mesial attachment surface to be directly involved when present. Periodontal ligament pressure was reported to range between 67 g/cm(2) and 132 g/cm(2). Configurations with rectangular attachments from second molar-to-canine and from first molar-to-canine present, in an in silico environment, almost equal efficiency in distalizing the upper second molar. However, attachments from the second molar to the canine are suggested to be adopted in clinical environments due to greater feasibility in everyday practice

Genetic programming for granular compactness modelling

The prediction of granular mixtures compactness is a recurring question common to many technical and scientific domains. Knowing the theoretical difficulties to predict the ideal solution, the general approach consists in seeking via an experimental approach, which is based on ideal grains distribution curves, an optimal mixtures. In this context, and faced to the empiricism of current approaches, several models have been developed. These models allow predicting granular mixture compactness to some extent. The compressible packing model which is an improved version of the solid suspension model based on the linear model of compactness is one of predictive models allowing the estimation of compactness on the basis of components characteristics and the compaction mode. However, this model in its initial form loses its predictive power because its use requires the measurement of some parameters based on the derivative of experimental curves. In this context, this study aims to present a model which allows predicting the granular mixtures compactness using the intrinsic parameters of components, easily accessible to experiment. The model is issued from the application of the genetic programming (GP) approach. This work presents a double interest: proposing a predictive model of granular mixture compactness with a new approach and demonstrating the GP reliability as a revolutionary tool which forms part of the machine learning algorithms, in complex phenomena modelling

NR2C - New Road Construction Concepts. Work Package 2: Interurban infrastructures. Concept and design of selected innovations for interurban infrastructure

The highway traffic size and loads have been continuously increasing all over Europe. At the same time, the expectations of users have been growing. They need more safe, durable and comfortable highway surfaces which make their trips low-cost and do not accept frequent traffic disturbance due to road maintenance and rehabilitation. The obvious answer of the highway engineering to this challenge is the continuous development and improvement of highway construction, rehabilitation and maintenance techniques further. The state-of-the art review of NR2C Work Package 2 on European highway innovations (Deliverable 2.1[1]) has clearly demonstrated the typical trends of innovative road construction, rehabilitation and maintenance which are as follows: • the use of very high quality (premium) basic materials eventually with their special treatment, • the establishment of sophisticated construction, rehabilitation and maintenance techniques utilising up-to-date scientific achievements, • the development of special measures for enhancing traffic safety even in extreme conditions, • decreasing the whole life (life cycle) costs of road pavements by constructing long-life variants with infrequent maintenance and rehabilitation need, and, consequently, minimal traffic disturbance, • the wider use of industrial by-products in road engineering without reducing pavement performance, • the wider use of recycling (eventually-re-use) of bound pavement structural layers in order to reduce the need for primary basic materials without jeopardising the performance of pavements, • giving priority to low-energy pavement structural variants reacting to the ever increasing energy prices and the limited availability of crude oil supplies, • there are some “blue sky” type innovations which utilise some new scientific results eventually coming from science areas far away from highway engineering. (...

A further polymorphism of the Gd locus for glucose-6-phosphate dehydrogenase present among blacks (Nigerians) and apparently absent among caucasoids: The quantitative isoelectrophoretic variation of the Gd+ allele

A structural but isoelectrophoretic moderate variation of glucose-6-phosphate dehydrogenase (G6PD) activity is common among Nigerians (a black population exposed to a long-lasting intense Plasmodium falciparum malarial endemia). It had never even been searched for among Caucasoids and Mongoloids. In the present work, we attempted to ascertain whether this polymorphism exists among Caucasoids. With this purpose, two Caucasoid male populations were studied: Sardinians and Romans, who respectively did and did not experience an evolutionarily effective exposure to P. falciparum. The approach adopted here consisted in comparing the variations of G6PD activity observed between brothers who certainly received their Gd gene from the same grandparent (hence Gd genes identical by descent) with those between brothers who received it (in the Roman series) or may have received it (in the Sardinian series) from different grandparents. No evidence for common moderate G6PD activity variations segregating with the Gd gene was found either in Romans or Sardinians, who have both been studied with much larger samples and more sensitive approaches than those which detected such type of polymorphism among Nigerians. The upper 95% confidence limit of such zero estimates for the frequency of the isoelectrophoretic quantitative Gd variant alleles were about 0.04 and 0.025 for Romans and Sardinians, respectively. This is the first example of a genetic region (the Gd gene with its flanking sequences) apparently monomorphic in a major race and with several (four) polymorphic sites in another major race

A further polymorphism of the Gd locus for glucose-6-phosphate dehydrogenase present among blacks (Nigerians) and apparently absent among caucasoids: The quantitative isoelectrophoretic variation of the Gd+ allele

A structural but isoelectrophoretic moderate variation of glucose-6-phosphate dehydrogenase (G6PD) activity is common among Nigerians (a black population exposed to a long-lasting intense Plasmodium falciparum malarial endemia). It had never even been searched for among Caucasoids and Mongoloids. In the present work, we attempted to ascertain whether this polymorphism exists among Caucasoids. With this purpose, two Caucasoid male populations were studied: Sardinians and Romans, who respectively did and did not experience an evolutionarily effective exposure to P. falciparum. The approach adopted here consisted in comparing the variations of G6PD activity observed between brothers who certainly received their Gd gene from the same grandparent (hence Gd genes identical by descent) with those between brothers who received it (in the Roman series) or may have received it (in the Sardinian series) from different grandparents. No evidence for common moderate G6PD activity variations segregating with the Gd gene was found either in Romans or Sardinians, who have both been studied with much larger samples and more sensitive approaches than those which detected such type of polymorphism among Nigerians. The upper 95% confidence limit of such zero estimates for the frequency of the isoelectrophoretic quantitative Gd variant alleles were about 0.04 and 0.025 for Romans and Sardinians, respectively. This is the first example of a genetic region (the Gd gene with its flanking sequences) apparently monomorphic in a major race and with several (four) polymorphic sites in another major race