•A comprehensive mathematical model for windblown sand transport and morphodynamic evolution of the sand bed is presented.•The model takes into account suspension in the air, saltation, erosion, ...deposition, turbulent diffusion, and avalanching.•Local slope modifies the shear-velocity threshold: a three-dimensional correction factor is proposed to include this effect.•Numerical simulations of both dunes evolution and windblown sand around mitigation measures are performed.
Modeling unsteady windblown sand dynamics requires not only treatment of the sand present in the air as a suspended constituent of a mixture but also consideration of erosion and sedimentation phenomena and consequently of the morphodynamic evolution of the sand-bed surface, including avalanching, especially in the presence of natural or human-built obstacles, artifacts, and infrastructures. With this aim in mind, we present a comprehensive multiphase model capable of accurately simulating all the physical phenomena mentioned above, producing satisfactory results, with reasonable computational effort. As test cases, two- and three-dimensional simulations of dune evolution are reported, as is windblown sand transport over a straight vertical wall. Examples of sand transport around other obstacles are given to show the flexibility of the model and its usefulness for such engineering applications.
Here, we present the results related to a new unique terrestrial ecosystem found in an englacial hypersaline brine found in Northern Victoria Land (Antarctica). Both the geochemistry and microbial ...(prokaryotic and fungal) diversity revealed an unicity with respect to all the other known Antarctic brines and suggested a probable ancient origin mainly due a progressive cryoconcentration of seawater. The prokaryotic community presented some peculiarities, such as the occurrence of sequences of Patescibacteria (which can thrive in nutrient-limited water environments) or few Spirochaeta, and the presence of archaeal sequences of Methanomicrobia closely related to Methanoculleus, a methanogen commonly detected in marine and estuarine environments. The high percentage (35%) of unassigned fungal taxa suggested the presence of a high degree of undiscovered diversity within a structured fungal community (including both yeast and filamentous life forms) and reinforce the hypothesis of a high degree of biological uniqueness of the habitat under study.
Porifera dominate vast areas of the Antarctic shelves and are successfully colonized by bacteria. Quorum sensing (QS) is a cell-to-cell communication system based on bacterial population density ...that, enabling the coordination of group-based behaviour, plays a critical role in the successful colonization of higher organisms, also driving the formation of biofilm for adhesion to surfaces. In this study, the production of
N
-Acyl homoserine lactones (AHLs), signal molecules involved in the QS mechanism, was examined for 211 Antarctic sponge-associated Gram-negative bacteria. AHL production was screened by using three different AHL biodetection systems, i.e.
Agrobacterium tumefaciens
pZLR4,
Chromobacterium violaceum
CV026 and
Pseudomonas putida
pKR-C12 with optimal sensitivity to moderate-chain (C8–C12), short-chain (C4–C8) and long-chain (≥ C14) AHLs, respectively. 57.8% of tested isolates activated at least one of the monitor systems used and belonged mainly to bacterial genera that are known to be involved in surface colonization by biofilm production. A thin-layer chromatographic assay based on the
A. tumefaciens
reporter system was utilized to determine the AHL profiles of five selected positive isolates. Visible spots on thin-layer chromatography (TLC) plates were produced by
Roseobacter
sp. TB60 and
Psychrobacter
sp. TB67 (both from the sponge,
Anoxycalyx joubini
). The former probably produced
N
-(3-oxohexanoyl)-L-homoserine lactone (similar to the standard 3-oxo-C6-HSL), whereas the isolate TB67 produced molecules that were similar to the standard
N
-butanoyl-homoserine lactone (C4-HSL). The obtained results demonstrated that AHL-based signalling may play a key role in sponge–bacteria interactions also in the Antarctic environment.
Abstract
Studies on the provenance of raw material used in the production of lapis lazuli artifacts can be particularly useful also in confirming or discarding the attributions given in past times by ...museum curators. In this work, a case study on five pieces belonging to the 19
th
century “Savoy Collection” of the Regional Museum of Natural Sciences in Turin is presented. The analysis allowed to assess the correctness of a previous Chilean attribution and to assign a provenance for the whole set of samples.
Superimposition of craniofacial structures from radiographic examination has been always used for assessing changes in the maxilla-mandibular complexes, especially for the evaluation of potential ...changes occurring during growth as well as after orthodontic treatment and/or maxillofacial surgery. However, the availability of cone beam computed tomography (CBCT) and the recent advancement in 3D imaging have allowed the development of specific techniques for the registration and superimposition of virtual three-dimensional anatomical structures, improving the diagnosis and treatment plan strategies. In the present paper, it will be discussed the evolution of superimposition techniques from the beginning (2D) to the newest 3D approach, describing the most used methods and their main advantages and disadvantages, focusing primarily on accuracy and reproducibility of each technique.
A description of the bacterial communities associated with the Mediterranean pennatulids (sea pens) Pennatula phosphorea and Pteroeides spinosum from the Straits of Messina (Italy) is reported. The ...automated ribosomal intergenic spacer analysis showed a marked difference between coral (tissues and mucus) and non-coral (underlying sediment and surrounding water) habitats. The diversity of the coral-associated communities was more deeply analysed by sequencing the 16S rRNA genes of bacterial clones. P. phosphorea and P. spinosum harbour distinct bacterial communities, indicating the occurrence of species-specific coral-associated bacteria. In addition, only few phylotypes were shared between mucus and tissues of the same pennatulid species, suggesting that there might be a sort of microhabitat partitioning between the associated microbial communities. The predominance of Alphaproteobacteria was observed for the communities associated with both tissues and mucus of P. phosphorea (84 and 58.2 % of total sequences, respectively). Conversely, the bacterial community in the mucus layer of P. spinosum was dominated by Alphaproteobacteria (74.2 %) as opposed to the tissue library that was dominated by the Gammaproteobacteria and Mollicutes (40.6 and 35.4 %, respectively). The antibacterial activity of 78 bacterial isolates against indicator organisms was assayed. Active isolates (15.4 %), which predominantly affiliated to Vibrio spp., were mainly obtained from coral mucus. Results from the present study enlarge our knowledge on the composition and antibacterial activity of coral-associated bacterial communities.
Periodontitis is the main cause of tooth loss and is related to many systemic diseases. Artificial intelligence (AI) in periodontics has the potential to improve the accuracy of risk assessment and ...provide personalized treatment planning for patients with periodontitis. This systematic review aims to examine the actual evidence on the accuracy of various AI models in predicting periodontitis.
Using a mix of MeSH keywords and free text words pooled by Boolean operators ('AND', 'OR'), a search strategy without a time frame setting was conducted on the following databases: Web of Science, ProQuest, PubMed, Scopus, and IEEE Explore. The QUADAS-2 risk of bias assessment was then performed.
From a total of 961 identified records screened, 8 articles were included for qualitative analysis: 4 studies showed an overall low risk of bias, 2 studies an unclear risk, and the remaining 2 studies a high risk. The most employed algorithms for periodontitis prediction were artificial neural networks, followed by support vector machines, decision trees, logistic regression, and random forest. The models showed good predictive performance for periodontitis according to different evaluation metrics, but the presented methods were heterogeneous.
AI algorithms may improve in the future the accuracy and reliability of periodontitis prediction. However, to date, most of the studies had a retrospective design and did not consider the most modern deep learning networks. Although the available evidence is limited by a lack of standardized data collection and protocols, the potential benefits of using AI in periodontics are significant and warrant further research and development in this area.
The use of AI in periodontics can lead to more accurate diagnosis and treatment planning, as well as improved patient education and engagement. Despite the current challenges and limitations of the available evidence, particularly the lack of standardized data collection and analysis protocols, the potential benefits of using AI in periodontics are significant and warrant further research and development in this area.
To evaluate the methodological feasibility of a RCT comparing skeletal changes of nasal cavity size obtained with RME and SME, assessed via CBCT.
Twenty Caucasian children with a mean age of 10.4 ...years were recruited and allocated to receive RME (10 subjects, mean age 10.4 years) or SME (10 subjects, mean age 10.5 years).
constricted maxillary arch, upper and lower first molars erupted, unilateral or bilateral posterior crossbite.
age above 15 years, history of previous orthodontic treatment, periodontal disease, systemic disease affecting craniofacial growth, or craniofacial congenital syndrome. CBCT examinations were performed before treatment (T0) and 7 months after expander removal (T1). Changes of nasal width (NW), palatal width (PW) and total nasal volume (TNV) were assessed; palatal and nasal expansion was also calculated as a percentage of the increase of intermolar width IMW (PW% and NW%).
The correlation between the first and the second readings ranged from 0.991 to 0.995 for linear measurements and was of 0.915 for volumetric measurements. The method error, as described by the value of ?, was in general less than 0.3 mm for linear measurements and 0.372 cm³ for volumetric measurements. All linear transverse skeletal and dental measurements and the nasal volume increased with both RME and SME protocols.
The reported methodology can be reasonably used to investigate the transverse dimension of nasal cavity. The PW% and NW% parameters more accurately described the efficacy of the two expansion protocols as compared to their corresponding absolute measurement (PW and NW).
The aim of the present prospective study was to evaluate the effectiveness of elastodontic appliance (EAs) in the treatment of subjects presenting Class II sagittal discrepancy in mixed dentition, ...and to evaluate palatal morphological development during treatment.
The study group, composed of 19 subjects, received treatment with EA for 1 year. The control group consisted of 17 untreated subjects.
age between 6 and 11 years, mixed deciduous dentition and skeletal and/or dental Class II malocclusion.
previous orthodontic therapy, systemic diseases and signs of temporal dysfunction. Skeletal and dentoalveolar parameters were compared between T0 and T1. A 3D imaging technology was used to compare palatal morphology obtained from intra-oral digital scans between T0 (pre-treatment) and T1 (post-treatment).
EAs can successfully mitigate early signs of malocclusion in Class II subjects as well as contribute to the harmonious development of the palate.
Considering the diagnostic capability offered by cone-beam computed tomography (CBCT), nowadays orthodontists often use this exam for treatment planning, especially in cases of impacted teeth, ...maxillary ipoplasia, orthognathic surgery etc. The aim of this study was to compare the radiation doses related to a conventional CBCT setting and that of a low dose protocol, usable in orthodontic practice. The absorbed organ doses were measured using an anthropomorphic phantom loaded with thermo-luminescent dosimeters related to sensitive organs (brain, bone marrow, salivary glands, thyroid, esophagus, oral mucosa, extrathoracic airways, lymph nodes). The device used was a MyRay Hyperion X9-11x5. The standard setting of the apparatus was 90 Kv, 36 mAs, CTDI/Vol 4.09 mGy, instead the low dose one was 90 Kv, 27 mAs, CTDI/Vol 2.89 mGy. Equivalent and effective doses have been calculated; the measurement of the effective doses was based on the ICRP recommendations. For the assessment of image quality, five readers, independent and experienced orthodontists, were asked to state if the images were sufficient enough to perform an orthodontic diagnosis. The lowest organ dose (5.01 microSv) was received by the esophagus during low dose CBCT acquisition. The highest mean organ dose instead (1227.67 microSv) was received by the salivary glands during conventional setting CBCT acquisition. Image quality has been considered sufficient for orthodontic diagnostic needs for both CBCT protocols. CBCT low dose setting should be preferred over the standard one in orthodontic practice, because it provides a significant lower radiation dose to the patients ensuring a good image quality. However, further studies are necessary to evaluate the opportunity of CBCT exams in orthodontic treatment planning.
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