Accuracy of generic mesh conformation: the future of facial morphological analysis

Three-dimensional (3D) analysis of the face is required for the assessment of changes following surgery, to monitor the progress of pathological conditions and for the evaluation of facial growth. Sophisticated methods have been applied for the evaluation of facial morphology, the most common being dense surface correspondence. The method depends on the application of a mathematical facial mask known as the generic facial mesh for the evaluation of the characteristics of facial morphology. This study evaluated the accuracy of the conformation of generic mesh to the underlying facial morphology. The study was conducted on 10 non-patient volunteers. Thirty-four 2-mm-diameter self-adhesive, non-reflective markers were placed on each face. These were readily identifiable on the captured 3D facial image, which was captured by Di3D stereophotogrammetry. The markers helped in minimising digitisation errors during the conformation process. For each case, the face was captured six times: at rest and at the maximum movements of four facial expressions. The 3D facial image of each facial expression was analysed. Euclidean distances between the 19 corresponding landmarks on the conformed mesh and on the original 3D facial model provided a measure of the accuracy of the conformation process. For all facial expressions and all corresponding landmarks, these distances were between 0.7 and 1.7 mm. The absolute mean distances ranged from 0.73 to 1.74 mm. The mean absolute error of the conformation process was 1.13 ± 0.26 mm. The conformation of the generic facial mesh is accurate enough for clinical trial proved to be accurate enough for the analysis of the captured 3D facial images

Assessing the outcome of orthognathic surgery by three-dimensional soft tissue analysis

Studies of orthognathic surgery often focus on pre-surgical versus post-surgical changes in facial shape. In contrast, this study provides an innovative comparison between post-surgical and control shape. Forty orthognathic surgery patients were included, who underwent three different types of surgical correction: Le Fort I maxillary advancement, bilateral sagittal split mandibular advancement, and bimaxillary advancement surgery. Control facial images were captured from volunteers from local communities in Glasgow, with patterns of age, sex, and ethnic background that matched those of the surgical patients. Facial models were fitted and Procrustes registration and principal components analysis used to allow quantitative analysis, including the comparison of group mean shape and mean asymmetry. The primary characteristic of the difference in shape was found to be residual mandibular prognathism in the group of female patients who underwent Le Fort I maxillary advancement. Individual cases were assessed against this type of shape difference, using a quantitative scale to aid clinical audit. Analysis of the combined surgical groups provided strong evidence that surgery reduces asymmetry in some parts of the face such as the upper lip region. No evidence was found that mean asymmetry in post-surgical patients is greater than that in controls

Method for Assessing the Fidelity of Optical Diffraction Tomography Reconstruction Methods

We use a spatial light modulator in a diffraction tomographic system to assess the accuracy of different refractive index reconstruction algorithms. Optical phase conjugation principles through complex media, allows us to quantify the error for different refractive index reconstruction algorithms without access to the ground truth. To our knowledge, this is the first assessment technique that uses structured illumination experimentally to test the accuracy of different reconstruction schemes.Comment: 11 PAGES, 6 FIGURE

The virtual human face – superimposing the simultaneously captured 3D photorealistic skin surface of the face on the untextured skin image of the CBCT Scan

The aim of this study was to evaluate the impact of simultaneous capture of the three-dimensional (3D) surface of the face and cone beam computed tomography (CBCT) scan of the skull on the accuracy of their registration and superimposition. 3D facial images were acquired in 14 patients using the Di3d (Dimensional Imaging, UK) imaging system and i-CAT CBCT scanner. One stereophotogrammetry image was captured at the same time as the CBCT and another one hour later. The two stereophotographs were then individually superimposed over the CBCT using VRmesh. Seven patches were isolated on the final merged surfaces. For the whole face and each individual patch; maximum and minimum range of deviation between surfaces, absolute average distance between surfaces, and standard deviation for the 90th percentile of the distance errors were calculated. The superimposition errors of the whole face for both captures revealed statistically significant differences (P=0.00081). The absolute average distances in both separate and simultaneous captures were 0.47mm and 0.27mm, respectively. The level of superimposition accuracy in patches from separate captures ranged between 0.3 and 0.9mm, while that of simultaneous captures was 0.4mm. Simultaneous capture of Di3d and CBCT images significantly improved the accuracy of superimposition of these image modalities

Assessment the Pb, Cu and Cd Deposition at Southern Bypass Roadside Soil in Damascus-Syria

Contamination of heavy metals represents one of the most pressing threats to water and soil resources as well as human health, and the Assessment the Pb, Cu and Cd deposition was studied by analyzing soil samples, where have been collected from one site located near the Damascus Homs highway in Damascus-Syria (Southern Bypass road), Sampling plots were marked in each area at 5, 10,15,20,25,30,35,40,45 , 50 and 100 meters distance from the road, Three soil samples were taken from each distance in all selected sites, and all samples were analyzed first for soil texture, organic matter and pH then the samples have been digested and analyzed by atomic absorption spectrophotometer for total metal concentrations. The results indicated that soils of study area were clay loamy and it was basic in nature. Where total soil Pb, Cu, and Cd concentrations varied from 62.56, 13.55 and 2.11 To 0.021, 0.12 and 0.00 mg kg−1 respectively. The highest heavy metals concentration was found at a distance of 5 meters from the road, and contents of metals tended to decrease with increasing distance from the highway, where the lowest concentration at 100 meter. The results showed that the soil near the highway had significant enrichment, particularly in Pb, and to a lesser extent with Cu and Cd. Dependence on the obtained results of heavy metals, the more we move away from the side of road, the fewer ratios of heavy metals will be obtained, and therefore safer distance for growing crops

Knowledge and attitude towards contraceptive use among adolescents in Africa: a systematic review

A 46% rate of unintended pregnancies among adolescents in Africa is a glaring notification of the barriers to contraception. There is little documentation of the knowledge and attitude towards contraceptive use among adolescents in Africa especially from systematic review perspective, which purposed this study. An E-literature search of the studies on the topic was conducted through PubMed, and Google Scholar, considering a period between January 2015 to August 2021. The search strategy used; “knowledge and attitude towards contraceptive use among adolescents in Africa”, which was sorted by date. The search resulted in 14,468 journal articles: 14,300 from Google Scholar, and 168 from PubMed but only 27 studies qualified for inclusion. Results indicate inadequate knowledge of contraception but this varies by age, level of education, marital status and geographical distribution. The majority of adolescents are aware of emergency contraception and traditional methods such as abstinence, lactational amenorrhea, and coïtus interruptus. Even with this knowledge, a larger proportion of adolescents do not use contraception due to limited access, misinformation on side effects and the negative attitude shaped by religious and socio-cultural beliefs and attitude of health care providers to them. Adolescent boys have more knowledge of contraception than the adolescent girls do but their use of contraceptives is not well documented. The low level of knowledge and negative attitude limits the use of these services and could be addressed by a well-informed approach on sexuality literacy and contraception that involves not only adolescents but also parents, the community and health care providers

The Use of Fluorescence Technology Versus Visual and Tactile Examination in the Detection of Oral Lesions: A Pilot Study

PURPOSE: This study compared the effectiveness of the VELscope(R) Vx versus visual and tactile intraoral examination in detecting oral lesions in an adult, high risk population. METHODS: The pilot study compared the intra oral findings between 2 examination types. The sample was comprised of 30 participants who were addicted to either cigarettes or a dual addiction (cigarettes plus hookah). High risk population was defined as males who were current cigarette smokers or had a dual addiction. Two trained and experienced licensed dental hygienists conducted all examinations. Throughout the study, all visual and tactile intraoral examinations were conducted first by one dental hygienist first, followed by the VELscope(R) Vx fluorescence examinations by the second dental hygienist. All subjects received an inspection of the lips, labial and buccal mucosa, floor of the mouth, dorsal, ventral and lateral sides of the tongue, hard and soft palate, and visual inspection of the oropharynx and uvula. Both evaluations took place in 1 visit in the Dental Hygiene Research Center at Old Dominion University and external sites. All participants received oral cancer screening information, recommendations, referrals for tobacco cessation programs and brochures on the 2 types of examinations conducted. RESULTS: Participants were considered high risk based on demographics (current smokers and mostly males). Neither visual and tactile intraoral examination nor the VELscope(R) Vx examination showed positive lesions. No lesions were detected; therefore, no referrals were made. Data indicated the duration of tobacco use was significantly higher in cigarette smokers (14.1 years) than dual addiction smokers (5 years) (p\u3e0.005). The average numbers of cigarettes smoked per day were 13.5 compared to 14.2 cigarettes for dual addiction smokers. CONCLUSION: Results from this study suggest the visual and tactile intraoral examination produced comparative results to the VELscope(R) Vx examination. Findings from this study support that the VELscope(R) Vx is still considered an adjunct technology and cannot be used exclusively for oral cancer screening

Validation of a new method for building a three-dimensional physical model of the skull and dentition

We present a new method for replicating the skull and occlusal surface with an accurate physical model that could be used for planning orthognathic surgery. The investigation was made on 6 human skulls, and a polyvinyl splint was fabricated on the dental cast of the maxillary dentition in each case. A cone beam computed tomogram (CBCT) was taken of each skull and a three-dimensional replica produced. The distorted dentition (as a result of magnification errors and streak artefacts) was removed from the three-dimensional model and replaced by new plaster dentition that was fabricated using the polyvinyl splint and a transfer jig replication technique. To verify the accuracy of the method the human skulls and the three dimensional replica model, with the new plaster dentition in situ, were scanned using a laser scanner. The three-dimensional images produced were superimposed to identify the errors associated with the replacement of the distorted occlusal surface with the new plaster dentition. The overall mean error was 0.72 and SD was (0.26) mm. The accuracy of the method encouraged us to use it clinically in a case of pronounced facial asymmetry

Geodiversity Examples of Morocco: From Inventory to Regional Geotourism Development

The soil and subsoil of Morocco are rich in geological phenomena that bear the imprint of a history which goes back in time more than 2000 million years. Very many geologically remarkable sites exposed in accessible outcrops, with good quality remained unknown to the general public and therefore deserved to be vulgarized. It is a memory to acquaint the present generations but also to preserve for future generations. In total, a rich geological heritage in many ways: Varied land- scapes, international stratotypes, various geological structures, varied rocks, mineral associations, a huge procession offossiles, remnants of oceanic crust (ophiolites) among oldests ones in the world (800 my), etc. For this geological heritage, an approach of an overall inventory is needed, both regionally and nationally, taking into account all the skills of the earth sciences. This will put the item on the natural (geological) potentialities as a lever for sustainable regional development. For this, it is necessary to implement a strategy of “geoconservation” for the preservation and as- sessment of the geological heritage. A website “lithothèque du Maroc” is under construction.info:eu-repo/semantics/publishedVersio

Non-linear analysis of two-layer timber beams considering interlayer slip and uplift

A new mathematical model and its finite element formulation for the non-linear analysis of mechanical behaviour of a two-layer timber planar beam is presented. A modified principle of virtual work is employed in formulating the finite element method. The basic unknowns are strains. The following assumptions are adopted in the mathematical model: materials are taken to be non-linear and can differ from layer to layer; interacting shear and normal contact tractions between layers are derived from the non-linear shear contact traction-slip and the non-linear normal contact traction-uplift characteristics of the connectors; the geometrically linear and materially non-linear Bernoulli's beam theory is assumed for each layer. The formulation is found to be accurate, reliable and computationally effective. The suitability of the theory is validated by the comparison of the numerical solution and the experimental results of full-scale laboratory tests on a simply supported beam. An excellent agreement between measured and calculated results is observed for all load levels. The further objective of the paper is the analysis of the effect of different normal contact traction-uplift constitutive relationships on the kinematic and static quantities in a statically determined and undetermined structure. While the shear contact traction-slip constitutive relationship dictates the deformability of the composite beam and has a substantial influence on most of the static and kinematic quantities of the composite beam, a variable normal contact traction-uplift constitutive relationship is in most cases negligible