Normal Orientation Research Articles

A rare case of total hip replacement in an 11-year-old female: rehabilitation goals and challenges - a case report

This case report describes a unique pediatric patient, the first and youngest in India, who underwent total hip replacement (THR) for right ankylosed hip. Patient presented with preoperative musculoskeletal deformities, posing challenges for postoperative rehabilitation. This 11-year-old female presented with non-traumatic insidious right hip pain, limping, right hip flexion and abduction deformity. Patient was diagnosed with idiopathic chondrolysis of the hip through exclusion and clinico-radiological findings. Patient underwent surgery for ceramic-on-ceramic THR. Fusion of triradiate cartilage and epiphysis and Risser’s skeletal maturity staging were confirmed. Postoperative examination revealed right hip flexion and abduction deformity resulting in pelvic obliquity, which led to limb length discrepancy and functional scoliosis. There was increased anterior pelvic tilt, altering the gait pattern. Adhering to THR restrictions, rehabilitation strategies were tailored to restore normal pelvic orientation and address deformities through manual stretching of right hip abductor, tensor fascia latae, iliopsoas and rectus femoris. A left-sided shoe raise was also given. Lumbar segmental muscle activation, pelvic floor muscle training and gait training were crucial parts of the rehabilitation protocol. At ten-week, prodigious outcomes were achieved in the form of complete pain relief, complete correction of abduction and flexion deformity, normal pelvic alignment in the frontal plane and independent, stable full weight-bearing ambulation after two years of disabling ordeal suffering. However, minimal compensation of the anterior pelvic tilt persisted. Rehabilitation of this challenging patient with multiple deformities achieved excellent outcomes at ten-week post-rehabilitation. Thus, a tailored meticulous rehabilitation program can significantly improve quality of life.

The Effect of Optimized Substrate Orientation on Layer Step in Laser Metal Deposition of Single-Crystal Nickel-Base Superalloys.

Laser metal deposition is a promising way to repair the surface defects of single-crystal components in turbo engines. Understanding the mechanisms and improving the efficiency of the repair have been long-standing problems. In this study, the influence of the substrate orientation on the laser metal deposition (LMD) was investigated and its effect on repair layer-step was examined. LMD experiments were conducted on single crystal superalloys with a normal substrate orientation (001)/[100] and with an optimized substrate orientation (101)/[101¯]. It reveals that the laser cladding with the optimized orientation leads to a larger height of the [001] dendrite region than that with the normal orientation. The calculated results of the growth velocity, thermal gradient, and susceptibility to CET in the dendrite-preferred growth direction indicate that, for the (101)/[101¯] orientation, the [001]/[100] boundary is located at relative high position in each layer, which not only decreases the formation ability of stray grain significantly, but also eliminates the appearance of the maximum susceptibility. This makes the necessary dilution position much higher, and thus, a large cladding step can be selected. Our findings could find potential applications in laser repair of single-crystal components.

Pair correlations and freezing transitions in a two-dimensional system of tilted axially symmetric quadrupoles

We study the pair structure and the transition from the liquid to the solid state in a system of axially symmetric charged particles confined to a two-dimensional plane and characterised by only one non-zero component of the electric quadrupole moment, which we assume to be inclined with respect to the perpendicular to the confining plane. The particles interact via anisotropic repulsive quadrupole–quadrupole interactions. The pair correlation functions (PCF) were calculated by solving the hypernetted chain integral equation (HNC) theory in the range of the tilt angle 75.0 ∘ ≤ 90 ∘ − ϕ ≤ 90 ∘ . NVT Monte Carlo (MC) simulations were also performed to test the accuracy of the PCFs. We find that the PCFs calculated with the HNC theory agree well with those of the MC simulation at smaller tilt angles and show anomalous behaviour with respect to the in-plane angular variation. The PCFs obtained with the HNC theory were used in the Ramakrishnan-Yussouff (RY) density functional theory (DFT) to investigate the transition between liquid and solid freezing. It was found that the RY DFT stabilises the triangular solid only for tilt angles ≥ 80 ∘ . When the tilt angle is decreased compared to the normal orientation of the quadrupoles, the transition density increases.

Stylizing Ribbons: Computing Surface Contours With Temporally Coherent Orientations.

Line work is a core element for the stylization of computer animations used by recent shows. However, existing stylization techniques are limited to edge treatments based on brush strokes or textures applied solely on top of curves. In this work, we propose new stylization effects by offering artists direct control over the inside and outside of surface contours. To this end, we introduce a method that creates ribbons, geometry strips of possibly varying width, that extrude from each side of the surface contour with temporally coherent orientations. Our contributions include the generation of spatially and temporally consistent normal orientations along visible contours and a trimming routine that converts arrangements of offset curves into ribbons free of intersections. We demonstrate the expressiveness and versatility of stylized ribbons by applying various effects on both character and shadow edges from animation sequences.

In situ X-ray diffraction evidence of field-induced transitions in a PbHfO3 single crystal

Antiferroelectric (AFE) materials are interesting due to recent discoveries of new prospective applications, although the mechanisms of the phase transitions that are at the heart of these applications remain incompletely understood. This work is devoted to the study of a single crystal of a model AFE, lead hafnate, by X-ray diffraction with in situ application of an electric field to trigger the transition to a polar phase. Two consecutive experiments were carried out on a 35 µm thick plate with [110] surface normal orientation over a field range from 0 to 330 kV cm−1 and back. A sharp drop in the intensity of R- and Σ-type reflections around 225 kV cm−1 was registered, with almost complete disappearance after 250 kV cm−1. This is compatible with a field-induced phase transition from the AFE to the R3m polar phase, which was suggested earlier on the basis of non-diffraction characterizations. X-ray diffraction reveals that the AFE domains with displacements parallel to the field direction react much more smoothly to the field, gradually reducing the AFE order at very small fields instead of holding it almost constant up to the critical field value, which is naturally expected. This expectation is fulfilled for domains with other orientations, but only for the first switching cycle; in the second switching cycle the AFE order already shows a notable decrease at subcritical fields. It is suggested that these observations could be linked with the antiphase domain wall population being affected by the field, which is consistent with the observation of diffuse rods between the Γ and Σ points. Another remarkable observation is the much smoother recovery of the AFE phase compared with its sharp disappearance at the critical field.

Exploring the Macroscopic Behavior and Microstructure Evolution of Lightly Cemented Sand in the Post-Liquefaction Process Using DEM.

This study investigates the post-liquefaction monotonic undrained shearing behavior of cemented sand at the macro- and microscales, using the discrete element method. A series of cyclic undrained triaxial tests with different stress amplitudes and post-liquefaction monotonic undrained triaxial tests were simulated on cemented sand with diverse cement contents (CCs). For comparison, a series of monotonic undrained triaxial tests on cemented sand without liquefaction (virgin cemented sand) were also modeled. The macroscopic behavior was analyzed in conjunction with the microscopic characteristics of the assembly, such as the deviator fabric of contact normal orientation, mechanical coordination number, energy components, and bond breakage. The results show that the DEM model can capture the effect of CC and cyclic stress ratio (CSR) on the undrained shear strength, stiffness, and pore pressure observed in laboratory experiments. Referring to the virgin specimen, with an increase in CC, the mechanical coordination number and the input work increment increase, while the deviator fabric for total contacts changes irregularly, leading to a greater initial stiffness and shear strength. In the case of the liquefied specimen, the smaller initial mechanical coordination number results in a very low initial stiffness regardless of CC. Contrary to the uncemented sand, both the mechanical coordination number and the input work increment decrease with an increasing CSR for the cemented sand. The microstructure evolution governs the effect of cementation level and liquefaction history on the macroscopic post-liquefaction behavior.

Association between carpal height ratio and ulnar variance in normal wrist radiography

IntroductionThe wrist joint is a complex anatomical structure, and various radiographic parameters are utilized to assess its normal alignment and orientation. Among these parameters are carpal height ratio (CHR) and ulnar variance (UV). Previous literature has indicated that factors such as age and gender may influence these parameters; However, there is a lack of studies investigating these differences specifically in the Middle East or Jordan. Additionally, no prior research has explored the relationship between UV and CHR. Therefore, the objective of this study is to investigate these critical radiological parameters and their associations.MethodologyA cross-sectional study design was employed, wherein a total of 385 normal wrist X-rays were reviewed, and CHR and UV were measured. Intra-observer and inter-observer reliability assessments were conducted to ensure the consistency and accuracy of measurements. Additionally, the association between UV and CHR was measured and plotted for further analysis.ResultsIn our study, the mean CHR was 0.5 (range: 0.4 to 1.5), and the mean UV was − 0.3 mm (range: -5.8 mm to 4.1 mm). We found a significant negative correlation between CHR and age (p < 0.05). No significant gender differences were observed in UV and CHR. Additionally, a weak positive correlation was found between UV and CHR (Pearson correlation coefficient = 0.13, p = 0.01; adjusted R2 = 0.014, p = 0.02).ConclusionAge correlated significantly with a decline in carpal height ratio. Additionally, ulnar variance had a week positive yet significant correlation with carpal height ratio.Level of evidenceCross-sectional study, Level III.

Multi-GPU 3D k-nearest neighbors computation with application to ICP, point cloud smoothing and normals computation

The k-Nearest Neighbors algorithm is a fundamental algorithm that finds applications in many fields like Machine Learning, Computer Graphics, Computer Vision, and others. The algorithm determines the closest points (d-dimensional) of a reference set R according to a query set of points Q under a specific metric (Euclidean, Mahalanobis, Manhattan, etc.). This work focuses on the utilization of multiple Graphical Processing Units for the acceleration of the k-Nearest Neighbors algorithm with large or very large sets of 3D points. With the proposed approach the space of the reference set is divided into a 3D grid which is used to facilitate the search for the nearest neighbors. The search in the grid is performed in a multiresolution manner starting from a high-resolution grid and ending up in a coarse one, thus accounting for point clouds that may have non-uniform sampling and/or outliers. Three important algorithms in reverse engineering are revisited and new multi-GPU versions are proposed based on the introduced KNN algorithm. More specifically, the new multi-GPU approach is applied to the Iterative Closest Point algorithm, to the point cloud smoothing, and to the point cloud normal vectors computation and orientation problem. A series of tests and experiments have been conducted and discussed in the paper showing the merits of the proposed multi-GPU approach.

Effects of particle overall regularity and surface roughness on fabric evolution of granular materials: DEM simulations

AbstractParticle shape irregularity is a notable feature of granular materials that exerts a profound influence on their mechanical behavior. This study examines the effects of particle overall regularity and surface roughness on the fabric evolution of granular materials using the Discrete Element Method (DEM). By connecting multiple spheres with varying sizes and positions, a diversity of clump particles characterized by distinct overall regularity () and surface roughness () are generated. A series of DEM simulations on drained triaxial compression tests have then been performed on granular assemblies with varying shapes, whereby their characteristics of contact intensity and the anisotropy of various fabric entities defined by contact normal, branch vector, and particle orientation, have been thoroughly investigated. The results show that increasing particle shape irregularity, indicated by smaller values of and , is generally associated with an enhanced internal structure within the granular assembly, exhibiting a higher mechanical coordination number and a greater fabric anisotropy. Conversely, in granular assemblies with relatively high overall regularity, the fabric anisotropy is notably reduced, and this reduction cannot be compensated by enhancements in particle surface roughness. The evolution of two contact‐related fabric anisotropies is analyzed in relation to particle orientation‐based fabric anisotropy, which is more profoundly influenced by particle overall regularity, underscoring its significant role in fabric evolution of granular materials.

Phenothiazine Embedded Dithiasmaragdyrins.

Two different types of novel phenothiazine-embedded dithiasmaragdyrins containing one phenothiazine ring, two thiophene rings and two pyrrole rings connected via three meso carbons and two direct bonds in the macrocyclic framework were synthesized over the sequence of synthetic steps starting with phenothiazine. Three examples of phenothiazine-embedded dithiasmaragdyrins were synthesized by condensing appropriate phenothiazine-based pentapyrrane with pentafluorobenzaldehyde and two examples of phenothiazine sulfone embedded dithiasmaragdyrins were synthesized by condensing phenothiazine-based diol with appropriate meso-aryl dipyrromethane under mild acid-catalysed conditions. 1D&2D NMR studies revealed that the thiophene rings adopted inverted orientation in phenothiazine sulfone embedded dithiasmaragdyrins whereas in phenothiazine-embedded dithiasmaragdyrins, the thiophene rings were in normal orientation. Both types of macrocycles exhibit nonaromatic absorption features and showed panchochromic absorption features in its neutral and protonated forms. The electrochemical studies indicated that the phenothiazine-embedded dithiasmaragdyrins were more electron-rich compared to phenothiazine sulfone embedded dithiasmaragdyrins. DFT studies revealed that both types of dithiasmaragdyrins exhibit significantly distorted structures and TD-DFT studies support the experimental observations.

Three-dimensional evaluation of dental characteristics in patients with Cleidocranial dysplasia

BackgroundCleidocranial dysplasia (CCD) is an autosomal dominant hereditary disorder. Besides skeletal abnormalities, CCD is often associated with dental complications, such as multiple supernumerary teeth and permanent teeth impaction or delayed eruption.MethodsSupernumerary teeth of axial, sagittal and coronal CBCT view was characterized in detail and 3D image reconstruction was performed. Number and location of teeth, morphology of supernumerary teeth, positional relationship between supernumerary and adjacent permanent teeth, direction of supernumerary teeth in CCD patients were analyzed.ResultsThe mean age of the 3 CCD patients in this study was 16.7 years. Among 36 supernumerary teeth, the majority of them were identified as apical side located and lingual side located. Normal orientation was the most common type in this study, followed by sagittal orientation, and horizontal orientation. Horizontal orientation teeth were all distributed in the mandible. Supernumerary teeth exhibited significantly shorter crown and dental-root lengths, as well as smaller crown mesiodistal and buccolingual diameters (P < 0.01). There was no difference in the number of supernumerary teeth between the maxilla and mandible, and the premolars region had the largest number of supernumerary teeth and the incisor region had the smallest number.ConclusionsThis study compares number and location of teeth, morphology of supernumerary teeth, positional relationship between supernumerary and adjacent permanent teeth and direction of supernumerary teeth, this study also provides a reference for the comprehensive evaluation of CCD patients before surgery.

Additive manufacturing of metallic metamaterials with enhanced mechanical properties enabled by microstructural and structural design

The emergence of additive manufacturing (AM) facilitates the fabrication of lightweight mechanical metamaterials characterized by intricate geometrical features. Here, we focus on the contributions of microstructural and structural design to the significant performance enhancement of metamaterials. Cubic plate-lattices featuring spherical holes were produced using laser powder bed fusion. Different from commonly used optimization of AM parameters to change the thermal histories and the resulting properties, we employ a simple strategy inspired by the crystallographic and AM features—tilting the build orientation. Compared to the normal build orientation, the tilted build orientation converts the printed microstructure of the plate-lattices from (100)-dominated to (111)- and (101)-dominated crystallographic texture and significantly refines the grain size, leading to remarkable 30% and 10% increases in the compressive strength and strain of the printed plate-lattices, respectively. For further tailoring the performance of metamaterials, we integrate a wavy plate topology design to improve the isotropy of properties and increase the impact attenuation. Our work paves the way to optimize additively manufactured metamaterials by combining microstructural and structural designs.

Zamzam Water Mitigates Cardiac Toxicity Risk through Modulation of GUT Microbiota and the Renin-angiotensin System.

Cardiovascular diseases (CVDs) continue to exert a substantial global influence in specific areas due to population growth, aging, microbiota, and genetic/environmental factors. Drinking water has a strong impact on the health of an individual. Further, emerging evidence has highlighted the therapeutic potential and benefits of Zamzam water (Zam). We investigated the influence of Zam on doxorubicin-induced cardiac toxicity, elucidating its consequential effects on GUT microbiota dysbiosis and hepatic and renal functions. Male rats were categorized into four groups: Group 1 as Normal control (NC), Group 2 as Zamzam control (ZC), Group 3 Disease control (DC) and Group 4 as Therapeutic control (DZ) treated with Zam against doxorubicin-induced disease at a dose of 1mg/kg boy weight) intraperitoneally (i.p). Significant dysbiosis in the composition of GM was observed in the DC group along with a significant decrease (p < 0.05) in serum levels of Zinc, interleukin-10 (IL-10), IL-6 and Angiotensin II (Ang II), while C-reactive protein (CRP), fibrinogen, and CKMB increased significantly (restoration of Zinc ions (0.72 ± 0.07 mcg/mL) compared to NC. Treatment with Zamzam exhibited a marked abundance of 18-times to 72% in Romboutsia, a genus of firmicutes, along with lowering of Proteobacteria in DZ followed by significant restoration of Zinc ions (0.72 ± 0.07 mcg/mL), significant (p ˂ 0.05) reduction in CRP (7.22 ± 0.39 mg/dL), CKMB (118.8 ± 1.02 U/L) and Fibrinogen (3.18 ± 0.16 mg/dL), significant (p < 0.05) increase in IL-10 (7.22 ± 0.84 pg/mL) and IL-6 (7.18 ± 0.40 pg/ml), restoration of Ang II (18.62 ± 0.50 nmol/mL/min), marked increase in renin with normal myocyte architecture and tissue orientation of kidney, and restoration of histological architecture of hepatocyte. Zam treatment mitigated cardiac toxicity risk through the modulation of GUT microbiota and the renin-angiotensin system and tissue histology effectively.

The Accuracy of Bone Assessment Distal to Lower Second Molars Using Panoramic Radiography: A Systematic Review and Meta-Analysis.

Panoramic radiography (OPG) evaluates mandibular third molar impaction (MTMI). This systematic review aimed to investigate the diagnostic accuracy of OPG in detecting bone loss distal to the lower second molars. The associated bone loss with different impaction positions and the most prevalent positions of MTMI were investigated as secondary outcomes. In January 2023, PubMed, Scopus, and Cochrane were searched to identify studies published between January 2012 and January 2023. Two examiners blindly selected the eligible studies for data extraction and quality assessment. Of 427 studies, 8 were suitable for data extraction. All studies reported bone loss distal to the second molar using OPG, ranging from 4.9 to 62.9%. The most frequent position of MTMI is mesioangular. The distal bone loss in the vertical and horizontal positions is statistically significant compared to typically positioned third molars and those that are fully erupted or impacted, but in a normal orientation (p-value 0.005 and 0.02, respectively). Bone loss was not statistically significant in the mesioangular position compared to other impacted positions (p-value 0.14). The risk of bias ranges between 66 and 88%. Despite its limitations, OPG is still considered a valuable tool to assess bone loss distal to the lower second molar in cases of an impacted mandibular third molar.

Learning Signed Hyper Surfaces for Oriented Point Cloud Normal Estimation.

We propose a novel method called SHS-Net for point cloud normal estimation by learning signed hyper surfaces, which can accurately predict normals with global consistent orientation from various point clouds. Almost all existing methods estimate oriented normals through a two-stage pipeline, i.e., unoriented normal estimation and normal orientation, and each step is implemented by a separate algorithm. However, previous methods are sensitive to parameter settings, resulting in poor results from point clouds with noise, density variations and complex geometries. In this work, we introduce signed hyper surfaces (SHS), which are parameterized by multi-layer perceptron (MLP) layers, to learn to estimate oriented normals from point clouds in an end-to-end manner. The signed hyper surfaces are implicitly learned in a high-dimensional feature space where the local and global information is aggregated. Specifically, we introduce a patch encoding module and a shape encoding module to encode a 3D point cloud into a local latent code and a global latent code, respectively. Then, an attention-weighted normal prediction module is proposed as a decoder, which takes the local and global latent codes as input to predict oriented normals. Experimental results show that our algorithm outperforms the state-of-the-art methods in both unoriented and oriented normal estimation.

Effects of mental rotation on map representation in orienteers-behavioral and fNIRS evidence.

Taking orienteering as an example, this study aimed to reveal the effects of mental rotation on orienteers' map representation and their brain processing characteristics. Functional near-infrared spectroscopic imaging (fNIRS) was used to explore the behavioral performance and cortical oxyhemoglobin concentration changes of map-represented cognitive processing in orienteering athletes under two task conditions: normal and rotational orientation. Compared to that in the normal orientation, athletes' task performance in the rotated orientation condition was significantly decreased, as evidenced by a decrease in correct rate and an increase in reaction time; in the normal orientation condition, blood oxygen activation in the dorsolateral prefrontal lobe was significantly greater than that in the ventral prefrontal lobe, which was significantly correlated with the correct rate. With rotating orientation, the brain oxygen average of each region of interest was enhanced, and the brain region specifically processed was the ventral prefrontal lobe, specifically correlating with the correct rate. Mental rotation constrains the map representation ability of athletes, and map representation in rotational orientation requires more functional brain activity for information processing. Ventral lateral prefrontal lobe activation plays an important role in the map representation task in rotational orientation.

Wedgeless V-Shaped Osteotomy of the Distal Medial Femur with Locking Plate Fixation for Correction of Genu Valgum in Adolescents and Young Adults.

Genu valgum is a common disorder affecting adolescents and young adults. Treatment of this disorder requires restoration of normal mechanical axis alignment and joint orientation, for which it is important to assess whether the deformity arises from the distal femur, knee joint, or proximal tibia. Most commonly, the deformity originates from the distal femur, and various osteotomies of the distal femur have been described1-6. The presently described wedgeless V-shaped osteotomy7,8 is a good option among the various alternative procedures listed below. The anesthetized patient is placed in the supine position on a radiolucent operating table. A bolster is placed beneath the knee to relax the posterior structures. A medial longitudinal skin incision is made that extends from the level of the medial joint line to 5 cm proximal to the adductor tubercle. The vastus medialis is identified and elevated anteriorly by detaching it from its distal and posterior aspects. The leash of vessels underneath the vastus medialis is identified, and the apex of the V-shaped osteotomy is kept just proximal to it. The anterior arm of the V is kept longer than the posterior one, both of them are kept perpendicular to each other, and the apex of the V is made to point distally. The osteotomy is performed on the medial cortex with use of an oscillating saw or multiple drill holes that are then connected using a thin osteotome. Care is taken not to utilize a saw or drill on the lateral cortex. A gentle valgus thrust is applied to break the lateral cortex without periosteal disruption. The apex of the V osteotomy on the proximal fragment is trimmed, and the deformity is corrected with varus force. The osteotomy site is stabilized with use of an anatomically contoured distal medial femoral locking plate or a medial proximal tibial L-shaped buttress plate (of the contralateral side). The implant position is verified under a C-arm image intensifier. The wound is closed in layers over a suction drain in a standard manner. Various types of corrective osteotomies of the distal femur have been described in the literature, including the lateral opening wedge, medial closing wedge, dome, and spike osteotomies1-6. All of these procedures have certain limitations and shortcomings. The wedgeless V-shaped osteotomy is another described procedure that is inherently stable7,8. It is a safe procedure and yields good clinical outcomes8,9. The posterior arm of the V-shaped osteotomy is kept smaller than the anterior arm. The proximal cortical bone is allowed to dig into the cancellous bone of the wider distal metaphysis during deformity correction. Trimming the apex of proximal bone end after making the osteotomy facilitates the process. In a study of 46 patients with a mean age of 16.9 years (range, 15 years to 23 years), Gupta et al.8 reported that the mean radiographic tibiofemoral angle improved from 22.2° (range, 16° to 29°) preoperatively to 5.1° (range, 0° to 10°) postoperatively (p < 0.001). Similarly, the mean lateral distal femoral angle improved from 79.2° preoperatively to 89.1° postoperatively (p < 0.001) and the mean mechanical axis deviation improved from 19.6 mm preoperatively to 3.7 mm postoperatively (p < 0.001). A total of 44 of 46 cases had an excellent functional outcome, with the other 2 having good outcomes. None of the patients in the study had an unsatisfactory outcome. It is important to keep the whole lower limb accessible to the image intensifier intraoperatively.Identification of the leash of vessels underneath the vastus medialis is important to decide the level of the osteotomy.It is important to preserve the periosteal sleeve on the lateral aspect of the femur. CORA = center of rotation of angulationECG = electrocardiogramLDFA = lateral distal femoral angleMAD = mechanical axis deviationMPTA = medial proximal tibial angle.

Supernumerary Tooth Patterns in Non-Syndromic White European Subjects.

Supernumerary teeth form at an incidence of about 3% in the population, with differences among races and various clinical consequences. Information on detailed patterns, and especially on white subjects, is scarce in the literature. Therefore, we aimed to investigate the patterns of non-syndromic permanent supernumerary teeth in a white European population. A record review was performed in different orthodontic clinics and identified 207 eligible individuals with 258 supernumerary teeth. Approximately 80% of the subjects had one supernumerary tooth, while 15% had two. Supernumerary tooth formation was more often evident in males (male/female: 1.65). However, there was no sexual dimorphism in its severity. The following pattern sequences, with decreasing prevalence order, were observed in the maxilla: 21 > 11 > 12 > 18 > 28 and in the mandible: 34 > 44 > 35 > 45 > 42. Supernumerary teeth were most often unilaterally present, without sexual dimorphism. In the maxilla, they were more often anteriorly present, whereas in the mandible, an opposite tendency was observed. Supernumerary teeth were consistently more often observed in the maxilla than in the mandible; 74% were impacted, 80% had normal orientation (13% horizontal, 7% inverted), and 53% had normal size. The present thorough supernumerary tooth pattern assessment enables a better understanding of this condition with clinical, developmental, and evolutionary implications.

A Molecular Dynamics Simulation to Shed Light on the Mechanical Alloying of an Al-Zr Alloy Induced by Severe Plastic Deformation

In a recent experimental work, as a result of severe plastic deformation, a non-equilibrium solid solution was obtained despite the very limited solubility of zirconium (Zr) in aluminum (Al). This opens up a new path in the development of heat-treatable alloys with improved electrical and mechanical properties, where mechanically dissolved elements can form intermetallic particles that contribute to precipitation strengthening. In the present study, molecular dynamics simulations were performed to better understand the process of mechanical dissolution of Zr within an Al model, with Zr atoms segregated along its grain boundaries. Stress–strain curves, radial distribution functions, and mechanisms of plastic deformation and dissolution of Zr in Al were analyzed. It is revealed that orientation of the grain boundary with segregation normal to the shear direction promotes more efficient mixing of alloy components compared to its parallel arrangement. This happens because in the second case, grain boundary sliding is the main deformation mechanism, and Zr tends to remain within the interfaces. In contrast, the involvement of dislocations in the case of normal orientation of grain boundaries with Zr segregation significantly contributes to deformation and facilitates better dissolution of Zr in the Al matrix. The findings obtained can provide new insights considering the role of texture during mechanical alloying of strongly dissimilar metals.

Friction and wear characteristics of Furcraea foetida fiber‐reinforced epoxy composites

AbstractIn the current study, the friction and wear properties of Furcraea foetida fiber‐reinforced epoxy composites were investigated. This study evaluated the effect of Furcraea foetida fiber content on the tribological behavior of composites. A water‐retting method was employed to extract the fibers, and resin transfer molding was used to fabricate the composites. The frictional force, coefficient of friction (COF), and wear rate were measured under dry test conditions and various applied loads (80, 100, 120, and 140 N). Microstructural analysis was conducted using scanning electron microscopy to investigate the surface morphology and wear mechanisms of the composites. The results revealed that the composite with 50 vol% of fibers exhibits the lowest frictional force and COF in both normal and parallel orientations with overall average COF of 0.43 in normal orientation and 0.42 in parallel orientation. Moreover, the composite with 60 vol% demonstrates the best wear resistance with an overall average specific wear rate of 2.1982 × in normal orientation and 4.3478 × () in parallel orientation. Overall, this study provides valuable insights into the tribological behavior of Furcraea foetida fiber‐reinforced epoxy composites and identifies the optimal volume fractions for improved friction and wear performance.Highlights Higher vol% yields denser composites with minimized voids. Normal fiber orientation shows maximum SWR of 10.0614 × () . Optimal frictional force and COF in 50 vol% composite. Enhanced wear resistance observed in 60 vol% composite. Higher vol% increases interfacial bonding and wear resistance in composites.