Vertical Deviation Research Articles

Pipkin Type-II Femoral Head Fracture - A Biomechanical Evaluation by the Finite-Element Method.

Objective To evaluate the biomechanical capacity of two forms of fixation for Pipkin type-II fractures, describing the vertical fracture deviation, the maximum and minimum principal stresses, and the Von Mises equivalent stress in the syntheses used. Materials and Methods Two internal fasteners were developed to treat Pipkin type-II fractures through finite elements: a 3.5-mm cortical screw and a Herbert screw. Under the same conditions, the vertical fracture deviation, the maximum and minimum principal stresses, and the Von Mises equivalent stress in the syntheses used were evaluated. Results The vertical displacements evaluated were of 1.5 mm and 0.5 mm. The maximum principal stress values obtained in the upper region of the femoral neck were of 9.7 KPa and 1.3 Kpa, and the minimum principal stress values obtained in the lower region of the femoral neck were of -8.7 KPa and -9.3 KPa. Finally, the peak values for Von Mises stress were of 7.2 GPa and 2.0 GPa for the fixation models with the use of the 3.5-mm cortical screw and the Herbert screw respectively. Conclusion The fixation system with the Herbert screw generated the best results in terms of reduction of vertical displacement, distribution of the maximum principal stress, and the peak Von Mises equivalent stress, demonstrating mechanical superiority compared to that of the 3.5-mm cortical screw in the treatment of Pipkin type-II fractures.

A numerical model-based deposition strategy for heat input regulation during plasma arc-based additive manufacturing

Heat accumulation in metal additive manufacturing (AM) processes leads to the unstable molten pool size, nonuniform track morphology, excessive dilution, and even structural collapse. Therefore, appropriate heat input management to alleviate heat accumulation is critical for metal AM processes. In order to mitigate heat accumulation and achieve better geometric accuracy, this work develops an innovative 3D numerical model-based deposition strategy to regulate the heat input for the metal AM process. Specifically, the proposed deposition strategy involves two steps: (i) a thermal simulation of the deposition process via an intelligent heat source tracking algorithm, thereby outputting a series of heat source data to ensure a constant molten pool size of the 3D model, and (ii) the output heat source data are utilized to regulate the heat input point-by-point of the deposit in the subsequent AM process. The proposed deposition strategy is demonstrated for plasma arc-based additive manufacturing (PA-AM) of a 20-layer Inconel 625 thin-walled deposit. The surface quality is measured with a profiler and the deviation of the deposits in the building direction is calculated by image processing techniques. The results show that the proposed deposition strategy is superior in geometric accuracy compared with the conventional approaches (i.e., the introduction of interlayer dwell time) from the perspectives of the forming height, surface morphology, and vertical deviation in the building direction. Meanwhile, benefitting from progressive forming and thermal management, PA-AM through the proposed approach can significantly reduce the total deposition time and energy consumption.

The use of lyophilized bovine pericardium (Tutopatch®) in the management of third nerve palsy following prior conventional strabismus surgery – a case series

ABSTRACT To study the secondary management of strabismus due to third nerve palsy using bovine pericardium (Tutopatch®) when previous conventional surgical therapy had failed. Review of our clinic records of selected patients with third nerve palsy, in whom residual deviation had been managed using Tutopatch® after previous surgical correction. The squint angle was measured preoperatively, and at 1 day, 3 months, and if possible 6 months postoperatively. Nine patients were enrolled in this study. One patient had mainly residual vertical deviation and was corrected with tendon elongation of the contralateral superior rectus. Three patients were operated on with tendon elongation of the lateral rectus muscle with or without medial rectus muscle resection and/or advancement (Group 1). Lateral rectus splitting after tendon elongation in addition to the resection and/or advancement of the medial rectus was performed in five patients with complete third nerve palsy (Group 2). In Group 1, the preoperative median squint angle was −20° (range −17° to −25°), which improved postoperatively to −4.5° (range −12° to +3°). In Group 2, the preoperative horizontal and vertical median squint angles were −27° (range −20° to −40°) and 0.5° (range 0° and 20°), respectively. Postoperatively, they had improved to −12.5° (range–2° to −25°), and 1.5° (range 0° to 7°), respectively. Two patients of Group 2 were re-operated due to residual exotropia. No postoperative complications were observed in any patient. In this small series several complex re-do situations of patients with third nerve palsy were evaluated in which Tutopatch® markedly improved outcomes after an initially ineffective surgical management. For better evaluation of its usefulness a study with more patients is recommended.

Muscle fenestration in vertical rectus muscle surgeries.

To evaluate the outcome of fenestration of the vertical rectus muscles in correcting vertical deviations. A retrospective chart review was conducted on patients who underwent fenestration surgery on the superior rectus (SR) or inferior rectus (IR) muscles. Ductions, versions, angle of deviations before and after surgery, and surgical details were analyzed. Success was defined as vertical alignment within 4 PD of orthophoria. Nineteen patients were identified. The mean age of the patients was 19.3 ± 13.1 (range; 4 to 48) years. The mean follow-up was 6.5 ± 2.7 (range, 3 to 12) months. Eleven patients presented with dissociated vertical deviation (DVD), 2 patients with sensory hypertropia, and 6 patients with sensory hypotropia. Fourteen patients had concomitant horizontal muscle surgery. The mean change of the angle of deviation was 13 ± 3 (range, 8 to 20) PD after SR fenestration. and 12 ± 2 (range; 10 to 15) PD after IR fenestration. There was a significant improvement in the post operative angle of deviation in both groups (P value <0.001). Success was achieved in 10 (77%) of patients who underwent SR fenestration and in all patients underwent ir fenestration. Only one patient in the IR group developed a 1-mm lower lid retraction. Fenestration of the vertical rectus muscles is an effective and safe method for correcting vertical deviations. We recommend increasing the amount of fenstration in DVD to further improve the outcome.

Conventional surgery versus botulinum toxin injection for the management of esotropia in children with Down syndrome

To compare the success rates of strabismus surgery and botulinum toxin injection (BTX) in treating esotropia in patients with Down syndrome (DS). This multicenter retrospective cohort study included all consecutive patients having DS with esotropia between 2014 and 2021 at King Abdullah Specialist Children Hospital, King Abdullah International Medical Research Center, and King Khaled Eye Specialist Hospital, Saudi Arabia. We divided the patients into two groups according to interventions. Success was defined as angle of deviation of <10Δ at final visit. A total of 53 patients were included: 23 in the surgery group and 30 in the BTX group. There were no significant differences between groups with regard to age, sex, diagnosis, spherical equivalent, and preoperative deviation angle. Before the intervention, the median angle of deviation was 30.0Δ (IQR, 30Δ-45Δ) in the surgery group and 37.5Δ (IQR, 28.8Δ-50.0Δ) in the BTX group (P = 0.802). Postoperatively, the median (IQR) deviation angle was 0.0Δ (0.0Δ-16.0Δ) in the surgery group and 22.5Δ (6.75Δ-30.0Δ) in the BTX group (P = 0.006). The success rate in the surgery and BTX groups was 65% and 30%, respectively (P = 0.011). Two patients developed dissociated vertical deviation in the surgery group. One patient presented consecutive exotropia and one inferior oblique overaction in the BTX group. In this study, conventional surgery showed a higher success rate than BTX in the management of esotropia.

Effects of offset design on the accuracy of bracket placement with aguided bonding device.

This study aimed to evaluate the effects of offset design on the accuracy of bracket placement for computer-aided design and computer-aided manufacturing (CAD/CAM)-guided bonding devices (GBDs) in vitro. Eight dental models were selected. Seven types of GBDs were designed and three-dimensionally (3D) printed for each model, including one without any offset and the other six with translation offsets (TF) and expansion offsets (EF) of 0.05, 0.10, and 0.15 mm, respectively. After the brackets were bonded on the models using the different GBDs in vitro, linear and angular deviations of the bracket positions were evaluated. In total, 56GBDs were printed, and 784 brackets were bonded using the GBDs. No misfit between the dentitions and the devices was found during the bonding process. With increasing offset, more brackets were gingivally positioned with the frequencies ranging from 61.61 to 76.79% for the TF groups and from 58.93 to 78.57% for the EF groups. The vertical deviations of the brackets increased from 0.100 to 0.168 mm and from 0.117 to 0.150 mm in the TF and the EF group, respectively, as offset increased. No statistically significant difference was found in the vertical deviation between most of the TF and EF groups with the same offset value (p > 0.05). With respect to angulation, the mean absolute deviations were 0.881, 1.083, and 1.029° in the 0.05-mm, 0.10-mm, and 0.15-mm EF groups, respectively, which were greater than those in the corresponding TF groups (0.799, 0.847, and 0.806°). Similarly, with increasing offset, the mean absolute deviations for rotation in the EF groups (0.847, 0.998, and 1.138°) were greater than those in the TF groups (0.853, 0.946, and 0.896°). Compared with the 0.15-mm TF group, greater angulations (p < 0.05) and rotations (p < 0.01) were found in the 0.15-mm EF group. Offset designs influenced the precision of vertical bracket placement with GBDs. Due to the smaller deviations in angulation and rotation of bracket placement, TF is preferred over EF for GBDs. Moreover, the differences between TF and EF also need to be considered in the design of other dental CAD/CAM devices.

Machine learning methods detect arm movement impairments in a patient with parieto-occipital lesion using only early kinematic information.

Patients with lesions of the parieto-occipital cortex typically misreach visual targets that they correctly perceive (optic ataxia). Although optic ataxia was described more than 30 years ago, distinguishing this condition from physiological behavior using kinematic data is still far from being an achievement. Here, combining kinematic analysis with machine learning methods, we compared the reaching performance of a patient with bilateral occipitoparietal damage with that of 10 healthy controls. They performed visually guided reaches toward targets located at different depths and directions. Using the horizontal, sagittal, and vertical deviation of the trajectories, we extracted classification accuracy in discriminating the reaching performance of patient from that of controls. Specifically, accurate predictions of the patient's deviations were detected after the 20% of the movement execution in all the spatial positions tested. This classification based on initial trajectory decoding was possible for both directional and depth components of the movement, suggesting the possibility of applying this method to characterize pathological motor behavior in wider frameworks.

Long-term outcomes of adjustable strabismus surgery at a Pakistani university hospital.

Strabismus, whether congenital or acquired, is a common visual and cosmetic problem, especially for the young. Adjustable suture strabismus surgery is not in vogue in our country. This technique gives the surgeon a second attempt to provide a better outcome for the patients. Our objective was to assess the long-term success of adjustable strabismus surgery in terms of postoperative alignment. We carried out a prospective study utilizing the fornix approach for adjustable strabismus surgery, in mainly horizontal, but also vertical strabismus in adults and cooperative children, to enhance the postoperative outcomes. The patient characteristics, preoperative deviation, type and pattern of strabismus, were evaluated and analyzed. The postoperative alignment was evaluated at 1year and beyond, to assess the success of this adjustable surgery. This study recruited 50 adults and children with a female predominance of 39 (78%); and with the mean age being 18.34 ± 9.88years. Exotropia was the primary diagnosis in the majority with 21(42%) cases; with purely horizontal strabismus in 23(46%) cases. The mean preoperative horizontal deviation was 48.76 ± 20.35prism diopters (PD) and the mean postoperative horizontal deviation was 2.73 ± 3.63 PD. The mean preoperative vertical deviation was 4.8 ± 8.54 PD whereas the mean postoperative vertical deviation was 0.86 ± 1.73 PD. The Wilcoxon Signed Ranks test analyzed the difference between the two which was statistically significant (p = 0.000). Surgical success, defined as postoperative horizontal alignment within ≤ 10 PD of orthotropia at the end of one year or more of follow-up after surgery, was achieved in 49 (98%) cases. The average follow-up was 21.47 ± 8.7months. Adjustable strabismus surgery has very good long-term outcomes in terms of postoperative alignment and patient satisfaction.

A hybrid deep learning approach for dynamic attitude and position prediction in tunnel construction considering spatio-temporal patterns

This study proposes a hybrid deep learning approach for dynamic attitude and position prediction of the tunnel boring machine (TBM) with high accuracy. By utilizing the key operational parameters as well as the historical value of TBM’s positions, the proposed deep learning model with graph convolutional network (GCN) and long short-term memory (LSTM), named GCN-LSTM, is constructed and trained to predict the vertical and horizontal deviations at the articulation and tail of TBM. Shapley Additive exPlanations (SHAP) analysis is then performed to improve the model’s interpretability and determine the key contributing factors. Data obtained from a realistic tunnel project in Singapore’s Thomson-East Coast line is utilized as a case study. The results indicate that: (1) The proposed GCN-LSTM approach provides accurate prediction with an average MAE of 1.009 mm, RMSE of 1.445 mm and R2 of 0.941. (2) The historical values of the deviation and adjustment are the major contributions to the current deviations, while the present adjustment could only influence the deviation in the future. (3) The proposed GCN-LSTM model outperforms the state-of-the-art methods in most metrics for the four outputs and thus is the most suitable method for the prediction. The proposed approach provides a reliable estimation of TBM’s position which assists in improving the overall project quality and reduces the risk of tunnel misalignments.

Vertical Deviation Caused by Tightening Torque on Implant Scan Body: An In Vitro Study.

This study evaluated the effects of manipulator level (ML) on implant scan body (ISB) seating. It also investigated ISB vertical deviation with various levels of tightening torque. In total, 10 standard acrylic resin models were prepared with the implant on the first molar site. ISBs were placed on the models by six operators with three MLs, manually and with a torque of 15 Ncm using an electronic torque driver. Digital scans were completed with an intraoral scan device. After superimposition in the software, ISB vertical deviation was compared between the 15 Ncm torque level and manual operation. One experienced operator then placed the ISB with different torque levels (20, 25, 30, and 35 Ncm) using an electronic torque driver. The ISB vertical deviation was also compared among torque levels. Vertical deviations within ML were analyzed using one-way analysis of variance (ANOVA). One-way repeated measures ANOVA was used to analyze the differences between torque levels (α = .05). ISB vertical deviations differed among MLs (P < .01). Significant vertical deviations were observed between 20 and 30 Ncm (P < .01), 20 and 35 Ncm (P < .05), and 25 and 35 Ncm (P < .05). The largest estimated marginal mean was 13.5 ± 4.11 μm with a torque of 35 Ncm. Significant differences in ISB vertical deviation were observed according to MLs and tightening torque levels. The amounts of those deviations did not exceed the previously described occlusal threshold.

The effect of different implant impression splinting techniques and time on the dimensional accuracy: An in vitro study

Background: Splinting of impression copings is generally recommended for complex implant-supported restorations. It can also be used in the digital workflow when a control model is needed to improve the fit of the prosthesis. However, there is a lack of knowledge on how dimensional accuracy is affected by different splinting techniques and time factors. ObjectivesTo evaluate the time factor on the dimensional stability of different implant impression splinting techniques used in the conventional and digital workflow. Materials and methodsTen pairs of implant analogs were fixed to a stainless steel bar. Modified impression copings were connected to the analogs and eight splinting strategies evaluated (n=10): (1) type I impression plaster (PLA), (2) autopolymerizing acrylic resin, cut and rejoin technique (PTR), (3) light-cured acrylic resin, cut and rejoin technique (ILC), (4) light-cured acrylic resin, no cutting and rejoining (ILN), (5) VPS bite registration material (SBR), (6) bis-acryl bite registration material (LXB), (7) bis‐acryl composite resin (PTP), (8) 3D printed splint (3DP). In each group, the position of modified impression copings was scanned with a laboratory scanner at different time points: (1) unsplinted impression copings (baseline), (2) 2 h after splinting, (3) 24 h after splinting. Modified impression coping design allowed using metrology software to measure and compare distance, vertical, angle and rotational deviations between impression copings. ResultsAll types of splints showed dimensional deviations. After 2 h of splinting, the lowest distance deviation was recorded in PTR (15.4±6.15µm), vertical deviation – in ILC (19.2±27.37µm), angle deviation – in ILC (0.08±0.1°), rotation – in LXB (0.2±0.24°) groups. Comparing results 2 and 24 h after connection of impression copings, statistically significant deviations in the distance were recorded in groups PLA (-5.6±5.95 µm), PTR (5.5±7.01µm), ILN (19.2±14.26µm), PTP (23.8±12.55µm). ConclusionsThe best dimensional accuracy was observed in the ILC group, followed by PTR and 3DP groups. Clinical significanceProper selection of splinting technique and polymerization time can increase the accuracy of conventional or digital impressions. Splinting techniques with rigid materials, proper polymerization and compensating for material shrinkage seem to produce the best results.

Disinsertion-distal myectomy and tucking of inferior oblique combined with superior oblique full tendon advancement in superior oblique palsy.

To assess the preliminary outcomes of inferior oblique (IO) disinsertion-distal myectomy and tucking combined with superior oblique (SO) full tendon advancement in patients with Knapp II or III superior oblique palsy. This single-centered retrospective study included 16 eyes from 13 patients with Knapp Class II or III SO palsy. All patients underwent IO disinsertion-distal myectomy and tucking combined with SO full tendon advancement while under general anesthesia. Pre- and post-operative levels of vertical deviation in the primary position, abnormal head position, IO hyperfunction and SO hypofunction, torsion, as well as the presence of diplopia, were all measured, and the differences were statistically compared. Pre-operatively, 12 patients had abnormal head positions, and two had diplopia. The pre-and post-operative levels of IO hyperfunction and SO hypofunction, as well as a vertical deviation in the primary position and torsion, all differed statistically significantly (p < 0.01). Inferior oblique disinsertion distal myectomy and tucking combined with SO full tendon advancement surgery appears to be an effective procedure in patients with congenital and acquired Knapp Class II or III SO palsy.

Three-dimensional laser scanning for large-scale as-built surveying of 2022 Beijing Winter Olympic Speed Skating Stadium: A case study

The latest 3D laser scanning technology is implemented in a practical project—2022 Beijing Winter Olympic Speed Skating Stadium—to investigate its effectiveness on the large-scale as-built surveying of civil infrastructures. The laser scanning was used for measuring the vertical deformation of flexible orthotropic cable net roof structure and for assessing the installation tolerance of curved glass curtain wall system. It was observed that 66% of clamps in the flexible roof structure showed vertical deviations within the range of ±5 mm and 94% of clamps showed deviations within ±10 mm. Additionally, about 60% of the vertical joints in transparent glass curtain wall showed deviations within the range of ±10 mm and the overall median deviation was only 2 mm. Given the complex structural form of the cable net roof structure and the glass curtain wall system, 3D laser scanning demonstrated unparalleled efficiency as compared to the conventional measuring methods.

Augmented inferior rectus transposition with medial rectus recession in treatment of chronic unilateral sixth nerve palsy

Backgroundto report the results of augmented inferior rectus muscle transposition (IRT) in management of chronic sixth nerve palsy.Methodsa retrospective review of medical records of patients with chronic complete sixth nerve palsy who were treated by augmented full thickness IRT to the lateral border of the paralyzed lateral rectus muscle. Patients were selected for IRT if there was more limitation of abduction in inferior gaze associated with V- pattern esotropia. Medial rectus recession (MRRc) was performed in case of positive intraoperative forced duction. Effect on primary position esotropia, face turn, amount of V-pattern and limitation of ocular ductions were reported and analyzed.Resultsthe review revealed 11 patients (7 males) with chronic unilateral sixth nerve palsy who were treated by simultaneous augmented IRT and MRRc. Causes of sixth nerve palsy were trauma (6 cases), vascular (3 cases), inflammation and congenital (one case each). Mean age of the patients at the time of surgery was 35.6 years (range; 11–63) and mean follow up was 8.6 months (range; 6–13). Postoperatively, average correction of esotropia, V-pattern, face turn and limited abduction were 35.9 PD, 11.4 PD, 25.9° and 2.2 unit, respectively (p < .00). Postoperative complications in the form anterior segment ischemia, symptomatic induced vertical deviations were not found.ConclusionsIn cases of chronic unilateral sixth nerve palsy associated with more limitation of abduction in downgaze and V-pattern esotropia, augmented IRT could be considered as an effective and safe modality.

Candidate Genes in Testing Strategies for Linkage Analysis and Bioinformatic Sorting of Whole Genome Sequencing Data in Three Small Japanese Families with Idiopathic Superior Oblique Muscle Palsy.

Idiopathic superior oblique muscle palsy is a major type of paralytic, non-comitant strabismus and presents vertical and cyclo-torsional deviation of one eye against the other eye, with a large vertical fusion range and abnormal head posture such as head tilt. Genetic background is considered to play a role in its development, as patients with idiopathic superior oblique muscle palsy have varying degrees of muscle hypoplasia and, rarely, the complete absence of the muscle, that is, aplasia. In this study, whole genome sequencing was performed, and single nucleotide variations and short insertions/deletions (SNVs/InDels) were annotated in two patients each in three small families (six patients in total) with idiopathic superior oblique muscle palsy, in addition to three normal individuals in one family. At first, linkage analysis was carried out in the three families and SNVs/InDels in chromosomal loci with negative LOD scores were excluded. Next, SNVs/InDels shared by the six patients, but not by the three normal individuals, were chosen. SNVs/InDels were further narrowed down by choosing low-frequency (<1%) or non-registered SNVs/InDels in four databases for the Japanese population, and then by choosing SNVs/InDels with functional influence, leading to one candidate gene, SSTR5-AS1 in chromosome 16. The six patients were heterozygous for 13-nucleotide deletion in SSTR5-AS1, except for one homozygous patient, while the three normal individuals were wild type. Targeted polymerase chain reaction (PCR) and direct sequencing of PCR products confirmed the 13-nucleotide deletion in SSTR5-AS1. In the face of newly-registered SSTR5-AS1 13-nucleotide deletion at a higher frequency in a latest released database for the Japanese population, the skipping of low-frequency and non-registration sorting still resulted in only 13 candidate genes including SSTR5-AS1 as common variants. The skipping of linkage analysis also led to the same set of 13 candidate genes. Different testing strategies that consisted of linkage analysis and simple unintentional bioinformatics could reach candidate genes in three small families with idiopathic superior oblique muscle palsy.

Study on the collision characteristics of a subway coupler

Derailment accidents caused by coupler buffer devices should not be underestimated. In this study, a particular type of subway was considered the research object, and a nonlinear finite element model of train collisions with a detailed coupler was established to study the collision characteristics of the coupler under different working conditions. First, the nonlinear mechanical characteristics of the coupler were analyzed. Then, a finite element model, including the energy absorption characteristics of the buffer and the collapse tube, the failure characteristics of the overload protection device, and the motion characteristics of the nodding and shaking head, was established and its reliability was verified. On this basis, a collision finite element model of a subway with four sections was developed. The attitude motion of the couplers and its influence on the derailment behavior of the vehicle was studied under the condition of initial vertical deviation or lateral deviation of the active and passive head couplers during their operation period. The results show that when the collision velocities are equal, the initial state of the head coupler barely affects the axial action characteristics and the pitching deflection angle attitude of the middle couplers; however, it has a certain effect on the yaw deflection angle. Furthermore, the initial state of the head coupler has a significant influence on its motion. The initial vertical deviation of the head coupler increases the derailment risk of the second section of the active subway. Moreover, the initial lateral deviation of the head coupler increases the derailment risk of the active subway and the first section of the passive subway. When the utilization rate of the head coupler is approximately 69%, the derailment risk of the vehicle is reduced.

Temporal Slant Recession of the Inferior Rectus Muscle: A Simple Surgical Treatment for Diplopia Caused by Small Vertical Deviations.

To evaluate the therapeutic effect of temporal slant recession of the inferior rectus muscle (TSRIRM) for the treatment of small vertical deviations in patients with vertical diplopia, with consideration of the theoretical additive effects of this procedure on ocular torsion and horizontal incomitance. Retrospective review of 11 patients who were treated with TSRIRM. Eight patients with vertical diplopia and small hyperdeviations (up to 6 prism diopters (PDs)) were treated with isolated TSRIRMs. Three patients with vertical diplopia from unilateral superior oblique palsies with large hyperdeviations (>15 PDs) were treated with TSRIRMs in conjunction with contralateral inferior oblique recessions. Six of the 8 patients with small vertical deviations had successful vertical realignment with elimination of symptomatic diplopia after an isolated TSRIRM. Two of the eight patients had residual hypertropia with symptomatic diplopia. Three additional patients with unilateral superior oblique palsy had successful vertical realignment with elimination of symptomatic diplopia after ipsilateral inferior oblique recession and contralateral TSRIRM. In total, 9 of 11 patients had successful surgical results after TSRIRM. TSRIRM provides an effective and reliable treatment for small angle vertical strabismus. Its ease of surgical access renders it useful for implementation in an outpatient neuro-ophthalmology setting.

Using Reinforcement Learning to Improve Airspace Structuring in an Urban Environment

Current predictions on future drone operations estimate that traffic density orders of magnitude will be higher than any observed in manned aviation. Such densities redirect the focus towards elements that can decrease conflict rate and severity, with special emphasis on airspace structures, an element that has been overlooked within distributed environments in the past. This work delves into the impacts of different airspace structures in multiple traffic scenarios, and how appropriate structures can increase the safety of future drone operations in urban airspace. First, reinforcement learning was used to define optimal heading range distributions with a layered airspace concept. Second, transition layers were reserved to facilitate the vertical deviation between cruising layers and conflict avoidance. The effects of traffic density, non-linear routes, and vertical deviation between layers were tested in an open-source airspace simulation platform. Results show that optimal structuring catered to the current traffic scenario improves airspace usage by correctly segmenting aircraft according to their flight routes. The number of conflicts and losses of minimum separation was reduced versus using a single, uniform airspace structure for all traffic scenarios, thus enabling higher airspace capacity.

Superior rectus recession for vertical strabismus with limitation of depression in abduction

Ocular misalignment can occur from a tight vertical rectus muscle, as is seen with thyroid eye disease. Hypertropia from a tight superior rectus is less common, but would show an increase in vertical deviation in the field of action opposite the involved muscle. We report outcomes of superior rectus recession for hypertropia increasing in downgaze.

W-Band 4th Order Waveguide Filter Based on Double Layer SU8 Microfabrication.

This paper investigates the fabrication accuracy of the W-band SU-8 photoresist micromachined 4th order waveguide bandpass filters (BPF). The designed filter based on cylindrical resonators is excited in TM010 mode. It is ideally suitable for the layered SU-8 micromachining process as the height of the resonator is much smaller than one wavelength, the electromagnetic fields remain unchanged in the thickness direction. The filter is composed of three silver-coated SU-8 layers based on a double-layer overlay process. Excellent manufacturing tolerances can be controlled within 4 μm in the thickness direction, around 10 μm in double-layer stacking accuracy, and an average of 1° in vertical angle deviation. Various challenges encountered in the SU-8 process are investigated while corresponding general solutions are proposed for machining high-precision devices. The measured results show a return loss of 12.4 dB and a minimum insertion loss of 0.8 dB, which are in agreement with the simulated one. Stress and deformation analysis are also conducted to confirm the maximum pressure that the filter can withstand and maintain good transmission performance.