Axis Points Research Articles

To Explore the Effect of Preoperative Hemodynamic Factors on The Outcome of Pseudolumen After Stanford Type B Aortic Dissection TEVAR Based on Computer Fluid Dynamics.

The preoperative aortic hemodynamic data of patients with Stanford type B aortic dissection were obtained by computer fluid dynamics (CFD). Then we explored the relationship between hemodynamic data and short-term residual pseudolumen after thoracic endovascular aortic repair (TEVAR) and predict the latter through the former. We collected the relevant data of 53 patients who underwent TEVAR in our hospital. They were divided into the A group (residual false lumen group) and B group (closed false lumen group), according to whether there was a residual false cavity around the stent recently after TEVAR. Three-dimensional reconstruction and CFD analysis of the thoracic and abdominal aorta was performed by DSCTA before the operation to obtain the aortic wall shear stress (WSS) and maximum blood flow velocity of the true and false lumen at the entrance, middle point of the long axis, and distal decompression port at the peak time of ventricular systolic velocity. Through the statistical analysis, we further studied the predictive value of hemodynamic data for residual pseudolumen. There was no significant difference in age, male, preoperative and postoperative thoracic and abdominal aorta DSCTA interval, history of hypertension, history of diabetes, smoking, Pt and APTT at admission between the two groups (P > 0.05). The blood flow velocity and shear stress at the entrance of the false lumen and the distal decompression port in the two groups were statistically significant (P < 0.05), while the other hemodynamic indexes were not statistically significant (P > 0.05). Binary logistic regression analysis further showed that the shear stress of the false lumen at the level of the distal decompression port (OR = 1.73, P = 0.01) was an independent risk factor for the residual false lumen around the stent in the early stage after TEVAR. The ROC curve analysis showed that the AUC area of the ROC curve corresponding to the shear stress of the false cavity at the level of the distal decompression port was 0.83, the best cross-sectional value was 9.49pa, and the sensitivity and specificity were 84.60% and 72.50%. The residual pseudolumen after TEVAR is related to the hemodynamic factors in the aorta before TEVAR. Preoperative hemodynamic data also have good predictive value. When the shear stress of the false lumen at the level of the distal decompression port is greater than 9.49pa, the probability of residual false lumen around the stent during the perioperative period significantly increases.

Accuracy of 3-dimensional printed bracket transfer tray using an in-office indirect bonding system

In this study, we aimed to evaluate and compare the bracket positioning accuracy of the indirect bonding (IDB) transfer tray fabricated in-clinic using the tray printing (TP) and marker-model printing methods (MP). The TP group was further divided into 2 groups (single-tray printing [STP] and multiple-tray printing [MTP]) depending on the presence of a tray split created using the 3-dimensional (3D) software. Five duplicated plaster models were used for each of the 3 experimental groups, and a total of 180 artificial teeth, except the second molar, were evaluated in the experiment. The dental model was scanned using a model scanner (E3; 3Shape Dental Systems, Copenhagen, Denmark). Virtual brackets were placed on facial axis points, and the IDB trays were designed and fabricated using a 3D printer (VIDA; EnvisionTEC, Mich). The accuracy of bracket positioning was evaluated by comparing the planned bracket positions and the actual bracket positions using 3D analysis on inspection software. The main effects and first-order interaction effects were analyzed together by analysis for the analysis of variance. The mean distance and height errors were significantly lower in the STP group than those in the MP and MTP groups (P<0.05). The mean distance error was 0.06 mm in the STP group and 0.09 mm in the MP and MTP groups. The mean height error was 0.10 mm in the STP group and 0.15 mm and 0.18 mm in MP and MTP groups, respectively. However, no significant differences were observed in the angular errors among the 3 groups. The in-office-fabricated IDB system with computer-aided design and 3D printer is clinically applicable after considering the linear and angular errors. We recommend IDB trays fabricated using the STP method owing to the lower frequency of bracket positioning errors and ease of fabrication.

Posterior Tibial Slope in Computer-Navigated Total Knee Arthroplasty: The Transmalleolar Sagittal Axis Underestimates Slope Compared to Traditional Intramedullary Axis.

Tibial slope in total knee arthroplasty (TKA) impacts knee flexion, balance, and ligament strain. Implants were initially designed with tibial slope recommendations based on the intramedullary axis. However, technology-assisted TKA, such as robotics or navigation, determines slope from the ankle-knee axis connecting the center of the transmalleolar line to the proximal exit point of the tibial shaft axis. We sought to quantify the difference in tibial slope between the traditional intramedullary and transmalleolar sagittal tibial axes. We retrospectively identified 40 TKAs with preoperative computed tomography scans. We reconstructed the 3-dimensional geometry of the tibia and fibula and determined the intramedullary axis as the best fit cylinder to the tibial shaft. We defined the transmalleolar axis according to accepted industry standards. We measured the angular difference between both axes in the sagittal plane. The transmalleolar axis was radiographically posterior to the intramedullary axis in 39 knees. Utilizing the transmalleolar axis to set posterior tibial slope would reduce the posterior tibial slope by a mean of 1.9° ± 1.3° compared to the intramedullary axis. Furthermore, the posterior slope would be reduced between 0° and 2° in 24 knees (60%), between 2° and 4° in 10 knees (25%), and more than 4° in 5 knees (13%). Tibial components implanted with technology assistance referencing the transmalleolar axis to set posterior slope will show an average of 1.9° less posterior slope when measured in sagittal plain radiographs, potentially concerning for knee kinematics.

Trajectory Planning and Optimization for Robotic Machining Based On Measured Point Cloud

Industrial robots are characterized by good flexibility and a large working space, and offer a new approach for the machining of large and complex parts with small machining allowances (extra material allowed for subsequent machining). Parts of this type (such as aircraft skin parts, wind turbine blades, etc.) are easily deformed due to their large scale and low stiffness. Therefore, these parts cannot be directly machined according to the designed model. A feasible method is to plan a robotic machining path by using the point clouds of parts after clamping from onsite measurement which contains inherent defects of measurement such as noise points and abrupt points. In this article, a novel method is proposed to plan and optimize a robotic machining path that meets the requirements of smoothness, dexterity, and stiffness based on the point cloud from onsite measurement. The dual nonuniform rational B-spline curves of the machining path points and tool axis points are generated at first. Next, an objective function of smoothness optimization is established to filter out the local mutation of the path by considering the constraints of both the deformation energy and the deviation. Then, the objective function of robot postures optimization is established to optimize dexterity and Cartesian stiffness of a robot during the machining process. To show the feasibility of the proposed method, simulation and experiments are carried out. It is proved that the proposed method can generate a smooth machining trajectory. The stability of joint rotation and the rigidity and dexterity of the robot are improved during the machining process.

Supramalleolar Lateral Opening-Wedge Osteotomy in Conjunction With Progressive Collapsing Foot Deformity Reconstruction for PCFD With Ankle Instability.

Reconstruction of progressive collapsing foot deformity (PCFD) with ankle instability (PCFD class E) remains a substantial challenge to orthopaedic surgeons. We report the outcomes of PCFD class E treated by means of a relatively standard PCFD foot reconstruction approach with the addition of a supramalleolar lateral opening-wedge osteotomy. We conducted a retrospective study of 13 patients (15 ankles) who underwent this procedure for PCFD class E between 2010 and 2021. Mean follow-up time was 3.8 (range, 2-6.3) years. Clinical assessment was based on the Japanese Society for Surgery of the Foot (JSSF) ankle/hindfoot scale as well as a Self-Administered Foot Evaluation Questionnaire (SAFE-Q). Radiographic assessments, including identification of the mechanical ankle joint axis point and a modified valgus Takakura-Tanaka osteoarthritis grade, were recorded. The mean JSSF score improved significantly from 45.2 preoperatively to 83.9 postoperatively (P < .001). SAFE-Q scores at the final follow-up were 70.1 for the pain and pain-related subscale, 75.4 for the physical functioning and daily living subscale, 83.0 for the social functioning subscale, 74.4 for the shoe-related subscale, and 78.1 for the general health and well-being subscale. Radiographic measurements showed improvement in the tibiotalar tilt angle (average improvement: 5.4 degrees); orientation of the talus joint line relative to the ground (average improvement: 14.0 degrees); anteroposterior talus-first metatarsal angle (average improvement: 11.2 degrees), talonavicular coverage angle (average improvement: 21.6 degrees), and lateral talus-first metatarsal angle (average improvement: 17.0 degrees). Postoperatively, the mechanical ankle joint axis point moved medially for all patients and into the medial half of the ankle joint for 7 patients. The modified osteoarthritis stage improved postoperatively in most cases. In this select and relatively small group of patients who had a supramalleolar lateral opening-wedge osteotomy combined with PCFD reconstruction, we measured general improvement in JSSF scores and radiographic variables. Long-term durability of the procedure remains unknown. This procedure may be an option for preserving the ankle joint in treatment of PCFD class E with osteoarthritis of the ankle. Level IV, therapeutic.

Accuracy of dental arch form in customized fixed labial orthodontic appliances

This study evaluated arch form accuracy with or without premolar extraction in customized fixed labial orthodontic appliance treatment. Setup and posttreatment digital models of 27 samples (15 extractions and 12 nonextractions) were selected and superimposed by best-fit surface-based registration in both the maxilla and the mandible. The facial axis points were identified and converted into Cartesian coordinates. A sixth-order polynomial equation was used to fit dental arches. Arch discrepancies (the mean distance between 2 arch forms) and similarities were compared between extraction and nonextraction groups, maxilla and mandible, and anterior and posterior arches. The arch discrepancy between extraction and nonextraction groups showed no statistically significant difference, but a statistically significant difference in arch similarity was found in the mandible. There were statistically significant differences between anterior and posterior arch discrepancies in the extraction (mandible) and the nonextraction (maxilla and mandible) groups. However, no statistically significant correlation was shown between anterior and posterior arch discrepancies. The arch similarities were 96.18% and 97.38% in the maxilla and 96.01% and 97.49% in the mandible between extraction and nonextraction groups. Arch form discrepancies and similarities showed a moderate correlation but no statistically significant differences between the maxilla and the mandible. In customized fixed labial orthodontic appliance treatment, arch form setup can be accurately achieved with and without premolar extraction. Anterior arch form acquires fewer discrepancies than the posterior arch, and overcorrection should be added to the end of the customized archwire to reduce posterior arch discrepancies. The discrepancy of the maxillary and mandibular arches is interrelated, and adjustments should be made on both maxillary and mandibular archwires to correct single-jaw transverse malposition.

Radiographic analysis using the hip-to-calcaneus line and its association with lower limb joint kinetics in varus knee osteoarthritis

BackgroundThis study aimed to (1) determine whether the hip to ankle (HA) line or hip to calcaneus (HC) line better reflects knee coronal plane kinetics, (2) to examine whether the HC line reflects ankle coronal plane kinetics, and (3) to evaluate the radiological and biomechanical aspects of ankle in varus knee osteoarthritis (OA). MethodsFull-length, postero-anterior radiographs (hip-to-calcaneus radiographs) were taken and gait analysis was performed in 21 varus knee OA patients. The %HA where the HA lines pass through the tibial plateau, and the %HC and the mechanical ankle joint axis point (MAJAP), where the HC line passes through the tibial plateau and tibial plafond, respectively, were calculated. Knee adduction angular impulse (KAAI) and ankle inversion angular impulse (AIAI) were collected as kinetic data. Finally, we divided the patients into two groups with and without ankle OA, and compared each parameter between both groups. ResultsThe %HA and %HC were correlated with KAAI (%HA; r = -0.68, P = 0.001, %HC; r = -0.81, P < 0.001, respectively) and MAJAP was correlated with AIAI (r = -0.55, P = 0.009). MAJAP was significantly smaller, and KAAI and AIAI were significantly larger in the ankle OA group. ConclusionsRadiographic analysis using the HC line was more strongly correlated to knee joint kinetics than the HA line and was also correlated to ankle joint kinetics. Assessing lower limb alignment using the HC line could be useful to evaluate the knee and ankle joints for varus knee OA.

Experimental investigation and analysis of thickness distribution in elliptically hydroformed Al6061T4 tube samples under different internal pressures

ABSTRACT In the present paper, the elliptical tube hydroforming samples have been deformed inside an elliptical die cavity with the help of internal pressure of water. Bulging thickness distribution of tube has been studied experimentally and numerically as well. The tube hydroforming process is depending on various hydroforming variables such as internal pressure, friction factor, axial force etc. In this experiment, axial feed is kept under constrained condition and performed under unique friction factor. The main attention of this paper is to measure the thickness at various major and minor axis points on tube sample deformed under different internal pressures. The percentage thinning of different major and minor axis points has been also discussed and plotted against simulated results. Finite element analysis (FEA) was carried out on elliptical samples using Abaqus software. The simulation results showed an agreement with the experimental data with some relative error which has been also plotted. Comparative results of incremental FEA prediction and experimental data have also been plotted with some deviation.

Physical Principles of Elastography: A Primer for Radiologists

AbstractElastography is the noninvasive method of qualitative and quantitative evaluation of strain and elastic modulus distribution in soft tissues. In simpler terms, elastography is the science of measuring tissue stiffness, the deviation of which correlates with pathology of the tissue/organs being evaluated. Whereas, elasticity, refers to the property of solid matter to return to their original shape and size after removal of the deforming forces. In all forms of elastography, irrespective of the types of deforming forces or moduli, the deformation of tissue occurs in the form of shear deformation. The velocity of shear waves in the deformed tissue depends on its density and on the shear modulus. The direction of propagation of shear wave is perpendicular to the inciting mechanical or acoustic wave. The shear wave is then subsequently tracked using multiple tracking pulses, which measures tissue displacement in response to the passing shear wave. The calculated speed of the shear wave is then converted to conventional Young's modulus for the purpose of computing the tissue stiffness.The currently used elastography techniques are static or quasi-static elastography and dynamic elastography. Strain elastography (a form of static or quasi-static elastography) is based on the principle of acquisition of radio-frequency (RF) signals before and after the application of a deforming force in the form of slight compression of tissue by a transducer. RF signals are compared between the pre-compression image data set and the post-compression image data set and correlated between the two data sets.Dynamic elastography may be either ultrasound (US) based or magnetic resonance (MR) based. The types of dynamic US elastography are: acoustic radiation force impulse imaging (ARFI), transient elastography (TE), point shear wave elastography (pSWE), and shear wave elastography (SWE). ARFI uses a standard transducer to produce and propagate rapid bursts of long focused ultrasound pulses, also called as “push pulses” which cause tissue deformity, the propagation of which is tracked using radio-frequency echo tracking. In TE, a probe mounted on a vibrator is used to produce a small thump by piston like motion of transducer. The shear wave which arises from the edges of the transducer is tracked using high pulse repetition frequency tissue Doppler and computed using M-mode for display of quantitative parameters. Point shear wave, also known as quantitative ARFI, uses shear waves generated using transient tissue displacement caused by ARFI and are subsequently subjected to tracking by Doppler. Shear wave elastography is based on the principles of imaging shear wave speed. An acoustic radiation force impulse is transmitted along the acoustic axis to produce tissue displacement and deformation at points of acoustic axis. The generated shear wave is imaged using RF echo tracking over a grid of points, which is translated into a real time image. MR elastography is a dynamic technique and the basic principles of MR elastography are the same as other forms of dynamic elastography. MR elastography has limited utility in iron-overload states and in addition, due to the large amount of time required for acquisition, the technique is not suitable for unstable patients.This review presents a simplified summary of the principles of elastography along with definition of the terms and the types of elastography which are currently available to radiologists for clinical application and concludes with a brief on the newer developments for the future.

Method for analyzing HR-TEM micrographs to propose and/or describe structures and their interaction in crystalline materials

A general and versatile method for the analysis and processing of HR–TEM data useful for several applications is presented. The first utility is to identify the structures seen in the micrographs; also can be extended to propose the interaction of structure dynamics between various phases; and also it can be hybridized with the chemical method to make a proposal of new structure and/or phase. The general method consisted of four steps: 1) micrograph pretreatment, 2) measurement of planar distances, 3) structure identification, and 4) structure corroboration. Crystallographic planes were immediately identified by comparing the interplanar distances. Next, crystallographic data were collected from the Crystal Structures Database (ICSD) and introduced into Diamond software to visualize the planes in each structure. In addition, from the zone axis point of view it must show the planes aligned, similar as is observed in the HR–TEM micrograph.•It was possible establish the growth mechanism of the different structures by identifying how is the structural interaction between the different oxides and sulfide phases.•Method was successful applied to propose a new TiCoMoS sulfide phase through HR–TEM results.•The method can also be extended to other areas where structural studies with HR–TEM are viable, such as biology, electronics, among others.

Orbital stability analysis of trajectories of highly nonlinear dynamic systems with feedback coupling

Orbital stability and qualitative study of the oscillations of a highly nonlinear dynamic system with feedback coupling are considered. For a highly nonlinear dynamic system with feedback coupling that satisfies Liénard’s theorem (on the existence and uniqueness of a periodic solution), a complete study of the phase pattern of the system is conducted. Applying the Poincaré criterion, the conditions for the existence of limit cycles and their Lyapunov stability are determined. The diagrams of phase trajectories are constructed numerically using the Mathcad 15 software package. Limit cycles are established, which are consistent with the limit cycles obtained by the Poincaré method. The behavior of trajectories outside the limit cycles is investigated. Recurrent homogeneous Pfaff equations are obtained, which determine the behavior of the systems “at infinity”. It was determined that the infinitely distant point of the horizontal axis is the only singular point for these equations. Linear approximations of recurrent homogeneous equations are obtained, which make it possible to determine the nature of the singular points. It was found that the trajectories then wind like a spiral on the limit cycles. Images of trajectories on the phase plane outside the limit cycles for the cases of degrees of nonlinearity under consideration are constructed.

A method for in vivo treatment verification of IMRT and VMAT based on electronic portal imaging device

BackgroundIntensity-modulated radiation therapy (IMRT) and volume-modulated arc therapy (VMAT) are rather complex treatment techniques and require patient-specific quality assurance procedures. Electronic portal imaging devices (EPID) are increasingly used in the verification of radiation therapy (RT). This work aims to develop a novel model to predict the EPID transmission image (TI) with fluence maps from the RT plan. The predicted TI is compared with the measured TI for in vivo treatment verification.MethodsThe fluence map was extracted from the RT plan and corrections of penumbra, response, global field output, attenuation, and scatter were applied before the TI was calculated. The parameters used in the model were calculated separately for central axis and off-axis points using a series of EPID measurement data. Our model was evaluated using a CIRS thorax phantom and 20 clinical plans (10 IMRT and 10 VMAT) optimized for head and neck, breast, and rectum treatments.ResultsComparisons of the predicted and measured images were carried out using a global gamma analysis of 3%/2 mm (10% threshold) to validate the accuracy of the model. The gamma pass rates for IMRT and VMAT were greater than 97.2% and 94.5% at 3%/2 mm, respectively.ConclusionWe have developed an accurate and straightforward EPID-based quality assurance model that can potentially be used for in vivo treatment verification of the IMRT and VMAT delivery.

Pengukuran Karakteristik Lahan Berbasis Internet of Things

Climate change is one of the factors that affect crop production, so it is necessary to implement strategies and technologies to maintain the availability of cereal crops in Indonesia. It is necessary to prepare the land for the early planting process and monitoring plant growth in order to produce maximum crops. Utilization of the Internet of Things (IoT) can be used to monitor soil temperature and pH in real time, so hope for the long term it can increase crop production. The purpose of this research is to make a prototype design system with Internet of Things (IoT) technology to obtain temperature and pH data. This tool will test the functional accuracy. This research for measuring the characteristics of land based on IOT uses a prototype method consisting of Communication, Quick Plan, Modelling Quick Design, Construction of prototype, and Development Delivery &amp; Feedback. Assembling the Wemos microcontroller, D1 R1, Breadboard, DS18B20 temperature sensor, 4700 Ohm Resistor, soil pH sensor, and 16x2 I2C LCD and connected using jumper cables with application control will be implemented into Wemos D1 R1 using the C++ programming language using Arduino IDE. Testing of the tool is carried out to ensure that the sensor is functionally able to read the temperature and pH of the soil correctly. Testing used black box method and was implemented in 5 land axis points at Politeknik Negeri Jember. The results used tools and litmus paper showed the same value. The conclusion and benefit of detecting land characteristics using the Wemos microcontroller showed more detailed measurement results with numbers behind the comma and a tool accuration rate of 100%.

Machine Learning Generated Synthetic Faces for Use in Facial Aesthetic Research.

Importance: A centralized repository of clinically applicable facial images with unrestricted use would facilitate facial aesthetic research. Objective: Using a machine learning neural network, we aim to (1) create a repository of synthetic faces that can be used for facial aesthetic research and (2) analyze synthetic faces according to contemporary aesthetic principles. Design, Setting, and Participants: Synthetic facial images were generated using an open source generative adversarial network. Images were refined and then analyzed using computer vision technology. Interventions: Not applicable. Main Outcomes and Measures: Synthetic facial images were created for use as a facial aesthetic research data set. Results: One thousand synthetic images were generated, and 60 images underwent analysis. Image attributes, including age, gender, image principle axis, facial emotion, and facial landmark points, were attained. Images demonstrated accordance with contemporary aesthetic principles of horizontal thirds and vertical fifths. Images demonstrated excellent correspondence when compared with real human facial photographs. Conclusions and Relevance: We have generated realistic synthetic facial images that have potential as a valuable research tool and demonstrate similarity to real human photographs while adhering to contemporary aesthetic principles.

Study on Distortion Compensation of Underwater Archaeological Images Acquired through a Fisheye Lens and Practical Suggestions for Underwater Photography - A Case of Taean Mado Shipwreck No. 1 and No. 2 -

Underwater archaeology relies heavily on photography and video image recording during surveillances and excavations like ordinary archaeological studies on land. All underwater images suffer poor image quality and distortions due to poor visibility, low contrast and blur, caused by differences in refractive indices of water and air, properties of selected lenses and shapes of viewports. In the Yellow Sea (between mainland China and the Korean peninsula), the visibility underwater is far less than 1 m, typically in the range of 30 cm to 50 cm, on even a clear day, due to very high turbidity. For photographing 1 m x 1 m grids underwater, a very wide view angle (180o) fisheye lens with an 8 mm focal length is intentionally used despite unwanted severe barrel-shaped image distortion, even with a dome port camera housing. It is very difficult to map wide underwater archaeological excavation sites by combining severely distorted images. Development of practical compensation methods for distorted underwater images acquired through the fisheye lens is strongly desired. In this study, the source of image distortion in underwater photography is investigated. We have identified the source of image distortion as the mismatching, in optical axis and focal points, between dome port housing and fisheye lens. A practical image distortion compensation method, using customized image processing software, was explored and verified using archived underwater excavation images for effectiveness in underwater archaeological applications. To minimize unusable area due to severe distortion after distortion compensation, practical underwater photography guidelines are suggested.

Study on Evolution Characteristics and Instability Model of Overburden Stress Shell with the Longwall Mining along Strike

Roof fracture is one of the main reasons for dynamic disaster in working face. During the process of long wall mining, due to the continuous fracture and collapse of roof, a stress shell composed of high stress is formed around the surrounding rock of the stope. The gravity of the overlying rock is transferred to the coal body around the stope through the stress shell. With the advancing of the working face, the stress shell has undergone the dynamic evolution process of the initial shell, extension shell, and flat shell. Based on the theory of shell and plate, the mechanical model of elliptical thin rock plate is constructed. The stress and bending moment distribution expressions of elliptic structure are obtained under two boundary conditions: the surrounding fixed-supported edges and simply supported edges. The results show that cracks begin to appear at the middle point of the semimajor axis and propagate along both ends of the semimajor axis. Then the fracture begins at the end of the semiminor axis, and the crack extends along the arc direction, forming an “X-O” type fracture. Finally, the mechanical nature of the stress shell instability is the result of the tensile fracture of the bedrock at the top of the shell.

Analytical potential of 3D data in the ballistic analyses of lithic projectiles

The total entry area of a projectile to the impacted object is a key ballistic parameter of lithic projectiles. Together with the assumed or experimentally testified penetration depth, it forms the first reception of the wounding capability of an individual projectile point, i.e., of the permanent wounding cavity volume. Mathematical operations are used to calculate the entry area, for which the manually measured dimensions of the projectile form input data. Nevertheless, these methods reconstruct only the cross-sectional area at only one point of the longitudinal axis of the object. Here, we propose a method of using high-resolution 3D data for precise measurements of the real entry area of a projectile, even in the case of barbed projectiles whose barbs exceed the width of the projectile body, as well as in cases of projectiles with an asymmetric cross-section. The proposed method of using 3D models to read the numerically expressed values of ballistic parameters was used to analyse almost 400 lithic archery projectiles found in the eastern part of Central Europe, dating from the Late Eneolithic and Early Bronze Age, a culminating period for lithic archery projectiles in the archaeological record.

Measuring standing hindfoot alignment: reliability of different approaches in conventional x-ray and cone-beam CT

IntroductionCurrently there is no consensus how hindfoot alignment (HA) should be assessed in CBCT scans. The aim of this study is to investigate how the reliability is affected by the anatomical structures chosen for the measurement.Materials and methodsDatasets consisting of a Saltzman View (SV) and a CBCT of the same foot were acquired prospectively and independently assessed by five raters regarding HA. In SVs the HA was estimated as follows: transversal shift between tibial shaft axis and heel contact point (1); angle between tibial shaft axis and a tangent at the medial (2) or lateral (3) calcaneal wall. In CBCT the HA was estimated as follows: transversal shift between the centre of the talus and the heel contact point (4); angle between a perpendicular line and a tangent at the medial (5) or lateral (6) calcaneal wall; angle between the distal tibial surface and a tangent at the medial calcaneal wall (7). Intraclass correlation coefficients (ICC) were calculated to assess inter-rater reliability. A linear regression was performed to compare the different measurement regarding their correlation.Results32 patients were included in the study. The ICCs for the measurements 1–7 were as follows: (1) 0.924 [95% CI 0.876–0.959] (2) 0.533 [95% CI 0.377–0.692], (3) 0.553 [95% CI 0.399–0.708], (4) 0.930 [95% CI 0.866–0.962], (5) 0.00 [95% CI − 0.111 to 0.096], (6) 0.00 [95% CI − 0.103 to 0.111], (7) 0.152 [95% CI 0.027–0.330]. A linear regression between measurement 1 and 4 showed a correlation of 0.272 (p = 0.036).ConclusionsIt could be shown that reliability of measuring HA depends on the investigated anatomical structure. Placing a tangent along the calcaneus (2, 3, 5, 6, 7) was shown to be unreliable, whereas determining the weight-bearing heel point (1, 4) appeared to be a reliable approach. The correlation of the measurement workflows is significant (p = 0.036), but too weak (0.272) to be used clinically.

Augmentation of the heat shock axis during exceptional longevity in Ames dwarf mice

How the heat shock axis, repair pathways, and proteostasis impact the rate of aging is not fully understood. Recent reports indicate that normal aging leads to a 50% change in several regulatory elements of the heat shock axis. Most notably is the age-dependent enhancement of inhibitory signals associated with accumulated heat shock proteins and hyper-acetylation associated with marked attenuation of heat shock factor 1 (HSF1)–DNA binding activity. Because exceptional longevity is associated with increased resistance to stress, this study evaluated regulatory check points of the heat shock axis in liver extracts from 12 months and 24 months long-lived Ames dwarf mice and compared these findings with aging wild-type mice. This analysis showed that 12M dwarf and wild-type mice have comparable stress responses, whereas old dwarf mice, unlike old wild-type mice, preserve and enhance activating elements of the heat shock axis. Old dwarf mice thwart negative regulation of the heat shock axis typically observed in usual aging such as noted in HSF1 phosphorylation at Ser307 residue, acetylation within its DNA binding domain, and reduction in proteins that attenuate HSF1–DNA binding. Unlike usual aging, dwarf HSF1 protein and mRNA levels increase with age and further enhance by stress. Together these observations suggest that exceptional longevity is associated with compensatory and enhanced HSF1 regulation as an adaptation to age-dependent forces that otherwise downregulate the heat shock axis.

Comparison of dental arch forms created from assessment of teeth, alveolar bone, and the overlying soft tissue.

The objective of this study was to determine whether there are differences among the arch forms created from assessments of tooth surfaces, alveolar bone, and overlying soft tissue. This study included 18individuals who presented with aclassI malocclusion, mild crowding, and acone beam computed tomography (CBCT) image of good diagnostic quality. The facial axis point was chosen to create the arch form from teeth, the Bowman-Kau (BK) point was used to establish the arch form from alveolar bone, and the WALA ridge was used to calculate the soft tissue arch form. Apredetermined algorithm was then used to create five separate arch forms per patient. These arch forms were categorized according to shape and were superimposed. The distances between the tooth-, bone-, and soft tissue-derived arch forms were calculated. The calculated distances between all arch forms were significantly different. The distances between the tooth- and bone-derived arch forms were larger for the mandible compared to the maxilla (mean 3.30 vs. 2.48 mm, respectively). The larger distances seemed to be located more posteriorly in the arch than anteriorly. The distance between tooth- and soft tissue-derived arch forms was largest for the second premolar (2.35 ± 1.59 mm), first molar (2.86 ± 0.63 mm), and second molar (3.25 ± 0.87 mm). There were no significant differences in the distance between the tooth- and either bone- or soft tissue-derived arch forms with regard to sex. The arch form shapes obtained from the teeth, alveolar bone, and soft tissue are correlated and show the same general shape. Although future large-scale studies are needed for confirmation, our results suggest that evaluating the easily visualized external features, including the WALA ridge, can adequately predict the underlying bone shape, and thus the desired arch form. Nevertheless, the shapes vary significantly between patients, so the final treatment plan should be individualized rather than relying on over-simplified general wire shapes.