Angle Coverage Research Articles

Radiographic Measurements of Pes Planovalgus Do Not Predict Clinical Outcomes in Tarsal Coalition Excision.

Many patients who undergo tarsal coalition excision have persistent postoperative pain. Most studies have utilized cat scan (CT) scan parameters of pes planovalgus and heel valgus but have found this to be an inconsistent predictor of outcomes. Plain radiographic parameters have been less utilized in trying to predict outcomes after coalition excision. Radiographic talonavicular coverage angle correlates with pain in patients with flexible pes planovalgus (PPV) but has not been studied in tarsal coalition population. Furthermore, foot alignment is not understood to change after simple coalition excision. The purpose of this study was to compare plain radiographic parameters, including talonavicular coverage angle, with pain after tarsal coalition excision, as well as compare preoperative and postoperative weight-bearing radiographs. Seventy-seven feet that underwent excision of the tarsal coalition had clinical outcomes and radiographic data collected >1 year postoperatively. Measures of PPV on preoperative and postoperative weight-bearing radiographs and CT scans were evaluated. Patients were an average of 13 years old at excision. Of the total, 65% had calcaneonavicular (CN) coalitions, whereas the remainder had talocalcaneal coalitions. All patients had significant postoperative improvement in clinical outcomes but 34% (13/38) had continued pain at the most recent follow-up, more so in talocalcaneal than CN coalitions (55% vs 26%, P < 0.001). The subset with CN coalitions had more severe preoperative PPV but greater postoperative PPV improvement. Except for a weak correlation between radiographic weight-bearing (anterior-posterior) talus-first metatarsal angle and pain with activity (r = -0.54), there were no other correlations between preoperative radiographic parameters and clinical outcomes. Heel valgus on CT did not correlate with radiographic measurements of PPV or pain. We did not find a correlation of radiographic PPV with persistent pain after tarsal coalition excision. We did find improvement in radiographic PPV in CN coalitions after treatment with simple excision. Heel valgus on CT was not a useful metric for evaluating PPV in the setting of a tarsal coalition. Level III-prognostic study.

Achieving Panoramic View Coverage in Visual Mobile Crowd-Sensing Networks for Emergency Monitoring Applications

Visual Mobile Crowd-Sensing(VMCS) collects photos by leveraging camera embedded in mobile users’ phones. There are two important issues in VMCS: determining whether photos collected by mobile users meet the requirements or not and designing an appropriate mechanism to attract mobile users to provide photos that meet the requirements. In this paper, we address those two issues when VMCS is applied to emergency monitoring applications. We first model an emergency scene as a disk region and define a coverage angle metric that quantifies the coverage ratio provided by each photo, and then formulate Maximize Coverage Angle under a Limited Budget(MCALB) problem. The goal of this paper is to recruit mobile users to provide panoramic view coverage for a disk while the total reward paid to participants does not exceed the budget. In our solution, we first propose a Coverage Angle Computation (CAC) algorithm to calculate the coverage angle of each uploaded photo. Then two incentive mechanisms: Guidance based Incentive Mechanism (GIM) and Coverage Prediction Incentive Mechanism (CPIM) are designed to encourage mobile users to upload photos with coverage angle that are not provided by other mobile users. Finally, we design a mobile app called I-share in android system to implement system. Meanwhile, we have recruited students to install I-share and simulated the information interaction between mobile users and server. We have conducted experiments by using I-share without/with embedded CAC algorithm to validate the efficiency of two incentive mechanisms. The experimental results demonstrate that our proposed incentive mechanisms effectively attract mobile users to provide panoramic view coverage of emergency scenes when the budget allows. Additionally, the CPIM outperforms the GIM, offering a higher coverage ratio with lower rewards.

Radiographically Apparent Acetabular Sourcil Landmarks Are Created by Comparable Regions of the Pelvis With Extraarticular Bone Variably Confounding Estimates of Joint Coverage.

The severity of hip dysplasia is characterized by radiographic measurements that require user definition of the acetabular sourcil edge, a bony landmark for which the corresponding three-dimensional (3D) anatomy is not well defined in any imaging plane. To use digitally reconstructed radiographs to determine: (1) What 3D anatomy is contributing to the "acetabular sourcil" location used to make lateral center-edge angle (LCEA) and anterior center-edge angle (ACEA) measurements in standing AP and false-profile radiographic views, respectively? (2) How do intraobserver and interobserver agreement in LCEA and ACEA translate into agreement of the 3D anatomy being evaluated? (3) How distinct are regions around the acetabular rim circumference that are evaluated by LCEA and ACEA measurements on radiographs? Between January 2018 and May 2019, 72 patients were indicated for periacetabular osteotomy to treat hip dysplasia or acetabular retroversion at our institution. From these patients, a series of 10 patients were identified of the first 12 patients in 2018 who were treated with periacetabular osteotomy, excluding two with missing or low-quality clinical imaging. A second series of 10 patients was identified of the first 11 patients in 2019 who were treated with periacetabular osteotomy and concurrent hip arthroscopy, excluding one who was missing clinical imaging. Pelvis and femoral bone surface models were generated from CT scans of these two series of 10 patients. There were 15 female and five male patients, with a median patient age of 18 years (IQR 17 to 23 years), a preoperative LCEA of 22° (IQR 18° to 24°), and a preoperative ACEA of 23° (IQR 18° to 27°). Exclusion criteria included missing preoperative CT or standard clinical radiographic imaging or severe joint incongruity. To address our first study question, digitally reconstructed radiographs matching each patient's standing AP and false-profile clinical radiographs were created from the segmented CT volumes. A board-certified orthopaedic surgeon and three trained researchers measured LCEA and ACEA on the digitally reconstructed radiographs, and the selected sourcil points were projected back into coordinates in the 3D anatomic space. To address our second study question, intraobserver and interobserver agreement in radiographic coverage angles were related to variations in 3D coordinates of the selected bony anatomy. Lastly, to address our third study question, 3D locations around the acetabular rim identified as contributing to the lateral and anterior sourcil points were summarized across patients in a clockface coordinate system, and statistical analysis of the "time" separating the 3D acetabular contributions of the sourcil edges was performed. The 3D anatomy contributing to the lateral sourcil was a variable length (27 mm [IQR 15 to 34 mm]) span of the laterosuperior acetabular edges, with contributions by the anterior inferior iliac spine in 35% (7 of 20) of hips. The anterior sourcil reflected a 28-mm (IQR 25 to 31 mm) span of bone from the medial ilium (posterior-medial to the anterior-inferior iliac spine and anterior-lateral to the arcuate line) to the anterior and lateral edges of the acetabulum. Interobserver variability was good for LCEA (intraclass correlation coefficient [ICC] 0.82 to 0.83) and moderate to good for ACEA (ICC 0.73 to 0.79), whereas the agreement in identified 3D sourcil locations varied widely (ICC 0.32 to 0.95). The acetabular edge of the 3D anatomy contributing to the anterior sourcil overlapped the circumferential range of the acetabular rim contributing to the lateral sourcil. Projection of two-dimensional radiographic landmarks contributing to the diagnosis of structural hip deformity into 3D allowed for the identification of the overlapping bony anatomy contributing to radiographically visible anterior and lateral sourcil edges. This work leveraging digitally reconstructed radiographs and 3D pelvis anatomy has found that bone outside the joint contributes to the radiographic appearance of the sourcil and may variably confound estimates of joint coverage. Furthermore, the substantial overlap between the acetabular bone contributing to measurement of the LCEA and ACEA would indicate that these angles measure similar acetabular deformity, and that additional measures are needed to assess anterior coverage independent of lateral coverage.

Talocalcaneonavicular Realignment: The Foundation for Comprehensive Reconstruction of Severe, Resistant Neurologic Cavovarus, and Equinocavovarus Foot Deformities in Children and Adolescents.

The progression of neurologic cavovarus (NCV) and equinocavovarus (NECV) foot deformities during growth can eventually lead to non-reducible severe talonavicular (TN) and subtalar (ST) joint rotational malalignments. This study aimed to describe a technique to correct severe, resistant inversion deformity of the ST joint complex as the foundational procedure in comprehensive reconstruction of multi-segmental NCV and NECV deformities in pediatric patients and to analyze mid-term radiologic, functional, and satisfaction outcomes. This prospective study included children with severe NCV and NECV foot deformities who underwent TCNR between 2019 and 2022, with a minimum follow-up of 2 years. Talocalcaneal angle, talus-1 metatarsal angles, and TN coverage angle were measured in preoperative and postoperative weight-bearing foot radiographs. The foot and ankle disability index, foot function index, and Maryland foot score evaluated functionality. Qualitative questions assessed perceived improvement, satisfaction, and expectations of patients/caregivers. Descriptive, comparative pre-post, subgroup, correlation, and satisfaction analysis were performed. Twenty-six patients (36 feet: 16 unilateral and 10 bilateral) were included; 50% were female, median age was 12.1 years (IQR, 3.21) and median follow-up was 32.9 months (IQR, 18.7). Fifty-four percent had cerebral palsy, and 23% had charcot-marie-tooth disease; 84.6% were ambulatory. Significant improvements were found in radiologic parameters and functional outcomes (P<0.01), with no relevant differences between unilateral or bilateral procedures, pathology, functional level, or ambulatory capacity (P>0.05). Correlations between radiologic parameters or functional scales with age were generally low. Most reported significant functional improvements, outcomes exceeding expectations, and high satisfaction; they would recommend the surgery and undergo the procedure again. There were 3 minor complications: hypersensitivity, partial recurrence, and undercorrection. The TCNR technique enables realignment of severe, resistant inversion deformity of the ST joint complex in NCV and NECV foot deformities. When combined with procedures to correct the other foot deformities and muscle imbalances, functional outcomes are enhanced, high patient/caregiver satisfaction is achieved, and low complication rates are possible. This approach represents an important modification and extension of an already described technique, the deep plantar-medial release. Level III, therapeutic prospective cohort study.

Large variability in degree of constraint of reverse total shoulder arthroplasty liners between different implant systems.

The liner design is a key determinant of the constraint of a reverse total shoulder arthroplasty (rTSA). The aim of this study was to compare the degree of constraint of rTSA liners between different implant systems. An implant company's independent 3D shoulder arthroplasty planning software (mediCAD 3D shoulder v. 7.0, module v. 2.1.84.173.43) was used to determine the jump height of standard and constrained liners of different sizes (radius of curvature) of all available companies. The obtained parameters were used to calculate the stability ratio (degree of constraint) and angle of coverage (degree of glenosphere coverage by liner) of the different systems. Measurements were independently performed by two raters, and intraclass correlation coefficients were calculated to perform a reliability analysis. Additionally, measurements were compared with parameters provided by the companies themselves, when available, to ensure validity of the software-derived measurements. There were variations in jump height between rTSA systems at a given size, resulting in large differences in stability ratio between systems. Standard liners exhibited a stability ratio range from 126% to 214% (mean 158% (SD 23%)) and constrained liners a range from 151% to 479% (mean 245% (SD 76%)). The angle of coverage showed a range from 103° to 130° (mean 115° (SD 7°)) for standard and a range from 113° to 156° (mean 133° (SD 11°)) for constrained liners. Four arthroplasty systems kept the stability ratio of standard liners constant (within 5%) across different sizes, while one system showed slight inconsistencies (within 10%), and ten arthroplasty systems showed large inconsistencies (range 11% to 28%). The stability ratio of constrained liners was consistent across different sizes in two arthroplasty systems and inconsistent in seven systems (range 18% to 106%). Large differences in jump height and resulting degree of constraint of rTSA liners were observed between different implant systems, and in many cases even within the same implant systems. While the immediate clinical effect remains unclear, in theory the degree of constraint of the liner plays an important role for the dislocation and notching risk of a rTSA system.

The 2024 LaBr[formula omitted](Ce) detector setup for the FAMU experiment

The FAMU experiment, led by INFN at the Rutherford Appleton Laboratory (UK), is designed to measure the Zemach radius of the proton in muonic hydrogen (μp) with uncertainty better than 1%. A set of LaBr3(Ce) scintillating crystals, complemented by a High-Purity Germanium (HPGe) detector, are used to detect the delayed muonic oxygen (μO) X-ray emission, which signals the muonic hydrogen spin flip excited with a tunable MIR laser. The detector setup is in continuous development. After two periods of measurement in 2023, the detector configuration is currently being upgraded for the 2024–2025 runs with new detectors read out by SiPMs to enhance signal-to-noise ratio and improve time performance. In particular, all ½” scintillators are being substituted with 1” ones, increasing the solid angle coverage and optimising energy resolution and timing performances.

Morphologically Switchable Twin Photonic Hooks

A dual fan-shaped structure covered with Ag films was investigated for generating twin photonic hooks (t-PHs). The t-PH characteristics of this structure are studied using the Finite-Difference Time-Domain (FDTD) method. The results show that by designing appropriate fan-shaped opening angles and angles of Ag films coverage, the switching between t-PHs, S-shaped t-PHs, and W-shaped t-PHs can be achieved, along with controlling over the bending angles. The maximum first, second, and third bending angles for the obtained W-shaped t-PHs are 51.3°, 36.4°, and 41.8°, respectively, while the Ag films angle is 5°. The investigated tunable morphology t-PHs provide innovative applications in the fields of nanolithography and integrated optics.

Lateral column lengthening versus subtalar arthroereisis for pes planovalgus in patients with cerebral palsy: a systematic review and meta-analysis.

Although pes planus, a common deformity in children with cerebral palsy (CP), is predominantly treated through lateral column lengthening (LCL), subtalar arthroereisis (SA) has also gained popularity for this purpose. This systematic review was conducted to compare surgical outcomes between LCL and SA for pes planovalgus in children with CP. PubMed, EMBASE, Cochrane Library, and Google Scholar were comprehensively searched for relevant articles reporting the outcomes of LCL and SA in the target population. Surgical outcomes were evaluated in terms of radiographic parameters and postoperative complications. This review included 22 studies involving patients undergoing LCL (LCL group) and 9 studies involving those undergoing SA (SA group). LCL outperformed SA in terms of corrections in the talonavicular coverage angle (8.1°-42.1° vs. 8.0°-30.7°), anteroposterior talo-first metatarsal angle (12.3°-33.7° vs. 9.8°-21.4°), and calcaneal pitch angle (2.5°-29.7° vs. 3.5°-8.0°). Furthermore, the risk of postoperative complications, such as recurrence, pain, undercorrection, and overcorrection, was higher in the LCL group than in the SA group. However, the risks of reoperation and implant-related problems were higher in the SA group than in the LCL group. A meta-analysis of two randomized studies revealed that improvement in calcaneal pitch angle was significantly greater in the LCL group than in the SA group (mean difference: 2.09°; P = 0.0488). LCL outperforms SA in correcting pes planus-related radiographic parameters in patients with CP. However, postoperative complications appear to be more common after LCL than after SA. https://inplasy.com/inplasy-2024-5-0126, Identifier 202450126.

Total Ankle Arthroplasty as a Correction Tool for Foot Deformities: Analyzing the Impact on Medial Column Alignment Adaptation Through Weightbearing Computed Tomography.

While weightbearing computed tomography (WBCT) has been instrumental in analyzing total ankle arthroplasty (TAA) positioning, there is a notable gap in the literature regarding adaptive changes in the foot's medial column after TAA. This study aims to bridge this gap by comparing preoperative and postoperative alignments of the foot's medial column and analyzing if a correlation exists between TAA coronal alignment correction and medial column alignment adaptation. Sixty patients who underwent a lateral approach TAA for end-stage osteoarthritis (OA) between January 2021 and April 2023 were included in this retrospective study. Patients were divided into varus (n = 30) and valgus (n = 30) groups. Preoperative and postoperative WBCT scans were analyzed to measure medial column alignment. Statistical analysis evaluated alignment corrections and correlations. Both groups showed significant plantarflexion of the second tarsometatarsal (TMT) angle, with a median adaptation of -1 degree (IQR -3, 0; P < .01) in the valgus group and -1 degree (IQR -3, 0; P = .03) in the varus group. The varus group exhibited increased plantarflexion of the first TMT angle (median -1 degree, IQR -1, -2; P = .03). Both groups demonstrated increased adduction of the medial column. The talonavicular coverage angle adaptation averaged 7.2 ± 14 degrees (P < .01) in the valgus and 9 ± 12 degrees (P < .01) in the varus group. The talo-first metatarsal axial angle adaptation was 5 ± 13 degrees (P = .03) in the valgus group and 9.5 ± 15 degrees (P = .08) in the varus group. WBCT analysis revealed significant medial column adaptation post-TAA in varus and valgus alignments. However, no correlation was found between hindfoot correction and forefoot adaptation, making it challenging to predict the need for additional realignment surgeries. Future studies should explore the relationship between tibiotalar correction and medial column alignment to improve outcomes and the influence of total ankle design on medial column adaptation. Level III, retrospective case control study.

Three-dimensional assessment of subchondral arc and hip joint coverage angles in the asymptomatic young adult hip.

The primary objective of this study was to develop a custom algorithm to assess three-dimensional (3D) acetabular coverage of the femoral head based on surface models generated from computed tomography (CT) imaging. The secondary objective was to apply this algorithm to asymptomatic young adult hip joints to assess the regional 3D acetabular coverage variability and understand how these novel 3D metrics relate to traditional two-dimensional (2D) radiographic measurements of coverage. The algorithm developed automatically identifies the lateral- and medial-most edges of the acetabular lunate at one-degree intervals around the acetabular rim based on local radius of curvature. The acetabular edges and the center of a best-fit sphere to the femoral head are then used to compute the mean 3D subchondral arc angles and hip joint coverage angles in five acetabular octants. This algorithm was applied to hip models generated from pelvis/hip CT imaging or abdomen/pelvis CT angiograms of 50 patients between 17 and 25 years of age who had no history of congenital or developmental hip pathology, neuromuscular conditions, or bilateral pelvic and/or femoral fractures. Corresponding 2D acetabular coverage measures of lateral center edge angle (LCEA) and acetabular arc angle (AAA) were assessed on the patients' clinical or digitally reconstructed radiographs. The 3D subchondral arc angle in the superior region (58.0 [54.6-64.8] degrees) was significantly higher (p < 0.001) than all other acetabular subregions. The 3D hip joint coverage angle in the superior region (26.2 [20.7-28.5] degrees) was also significantly higher (p < 0.001) than all other acetabular subregions. 3D superior hip joint coverage angle demonstrated the strongest correlation with 2D LCEA (r = 0.649, p < 0.001), while 3D superior-anterior subchondral arc angle demonstrated the strongest correlation with 2D AAA (r = 0.718, p < 0.001). The 3D coverage metrics in the remaining acetabular regions did not strongly correlate with typical 2D radiographic measures. The discrepancy between standard 2D measures of radiographic acetabular coverage and actual 3D coverage identified on advanced imaging indicates potential discord between anatomic coverage and the standard clinical measures of coverage on 2D imaging. As 2D measurement of acetabular coverage is increasingly used to guide surgical decision-making to address acetabular deformities, this work would suggest that 3D measures of acetabular coverage may be important to help discriminate local coverage deficiencies, avoid inconsistencies resulting from differences in radiographic measurement techniques, and provide a better understanding of acetabular coverage in the hip joint, potentially altering surgical planning and guiding surgical technique.

Robust adaptive beamforming for cylindrical uniform conformal arrays based on low-rank covariance matrix reconstruction

Recently, conformal arrays have attracted considerable interest because such arrays can provide reduced radar cross-section and increased angle coverage. In this article, we devise a robust adaptive beamforming (RAB) approach using cylindrical uniform conformal array (CUCA). Firstly, we derive the minimum variance distortionless response (MVDR) beamformer for the CUCA by utilizing the noise subspace of interference covariance matrix (ICM) and steering vector (SV) of the signal-of-interest (SOI). Subsequently, the ICM is reconstructed by estimating the noise-free covariance matrix of the CUCA outputs and the interference projection matrix. Specifically, the noise-free covariance matrix can be regarded as multiple low-rank covariance matrices, and each low-rank matrix is reconstructed by formulating a nuclear norm minimization (NNM) problem. With the reconstructed covariance matrix, the 2-D DOAs of sources are determined by employing 2-D MUSIC spectrum to form the interference projection matrix. In addition, the SOI SV is estimated by solving a quadratically constrained quadratic programming (QCQP) problem. Numerical results demonstrate that the proposed approach is obviously superior to the existing RAB techniques.

Correlation of progressive collapsing foot deformity with varus knee alignment in young adults – A case control study

BackgroundMajority of patients with Progressive Collapsing Foot Deformity(PCFD) have symptoms pertaining to the knee. Malalignment at the foot will have effects on the alignment of the knee. In this case control study, we compare the alignment of the knees between patients with PCFD and controls. MaterialsSixty subjects, 30 PCFD and 30 controls, underwent radiographs in which the tibiofemoral angle and radiological parameters of PCFD were assessed. Parameters of PCFD were correlated with the tibiofemoral angle. ResultsMean tibiofemoral angle was 3.8° among the cases and 4.8° among the controls which was statistically significant(P = 0.001). Varus knee alignment was seen in 41 out of 60 limbs with PCFD which was statistically significant(P < 0.001). The tibiofemoral angle correlated significantly with the Meary angle(P = 0.03) and the talonavicular coverage angle(P = 0.003). ConclusionsPCFD is associated with varus knee malalignment. This varus deformity early in adulthood may lead to deleterious effects like medial compartment osteoarthritis in later life. Early intervention for such patients may help avoid this knee damage. Level of evidenceLevel 3-prognostic.

Morphological changes in flatfoot: a 3D analysis using weight-bearing CT scans

BackgroundFlatfoot is a condition resulting from complex three-dimensional (3D) morphological changes. Most Previous studies have been constrained by using two-dimensional radiographs and non-weight-bearing conditions. The deformity in flatfoot is associated with the 3D morphology of the bone. These morphological changes affect the force line conduction of the hindfoot/midfoot/forefoot, leading to further morphological alterations. Given that a two-dimensional plane axis overlooks the 3D structural information, it is essential to measure the 3D model of the entire foot in conjunction with the definition under the standing position. This study aims to analyze the morphological changes in flatfoot using 3D measurements from weight-bearing CT (WBCT).MethodIn this retrospective comparative our CT database was searched between 4–2021 and 3–2022. Following inclusion criteria were used: Patients were required to exhibit clinical symptoms suggestive of flatfoot, including painful swelling of the medial plantar area or abnormal gait, corroborated by clinical examination and confirmatory radiological findings on CT or MRI. Healthy participants were required to be free of any foot diseases or conditions affecting lower limb movement. After applying the exclusion criteria (Flatfoot with other foot diseases), CT scans (mean age = 20.9375, SD = 16.1) confirmed eligible for further analysis. The distance, angle in sagittal/transverse/coronal planes, and volume of the two groups were compared on reconstructed 3D models using the t-test. Logistic regression was used to identify flatfoot risk factors, which were then analyzed using receiver operating characteristic curves and nomogram.ResultThe flatfoot group exhibited significantly lower values for calcaneofibular distance (p = 0.001), sagittal and transverse calcaneal inclination angle (p < 0.001), medial column height (p < 0.001), sagittal talonavicular coverage angle (p < 0.001), and sagittal (p < 0.001) and transverse (p = 0.015) Hibb angle. In contrast, the sagittal lateral talocalcaneal angle (p = 0.013), sagittal (p < 0.001) and transverse (p = 0.004) talocalcaneal angle, transverse talonavicular coverage angle (p < 0.001), coronal Hibb angle (p < 0.001), and sagittal (p < 0.001) and transverse (p = 0.001) Meary’s angle were significantly higher in the flatfoot group. The sagittal Hibb angle (B = − 0.379, OR = 0.684) and medial column height (B = − 0.990, OR = 0.372) were identified as significant risk factors for acquiring a flatfoot.ConclusionThe findings validate the 3D spatial position alterations in flatfoot. These include the abduction of the forefoot and prolapse of the first metatarsal proximal, the arch collapsed, subluxation of the talonavicular joint in the midfoot, adduction and valgus of the calcaneus, adduction and plantar ward movement of the talus in the hindfoot, along with the first metatarsal’s abduction and dorsiflexion in the forefoot.

Interface engineering strategy in bimetallic carbide and cobalt nanoparticles encapsulated in N-doped carbon nanotubes for excellent microwave absorption

In this paper, bimetallic Zn/Co zeolitic imidazole frameworks (Zn/Co-ZIFs) with various Zn/Co ratios have been successfully synthesized via a facile coprecipitation method, and then were converted into a series of N-doped bamboo-like carbon nanotubes (CNTs) encapsulated in Co nanoparticles with the aid of dicyandiamide after an annealing process. Results show that when the Zn/Co ratios in the Zn/Co-ZIF are 2:1 and 1:2, the morphology of ZIFs is hexagonal-star-like shape while it presents rod-like shape at the Zn/Co ratio of 1:1. The corresponding derivatives of these ZIFs after carbonization are identified as Co3ZnC/Co@CNTs, Co@CNTs-12, and Co@CNTs-11, and their microwave absorption performances are investigated at the same time. Among these as-synthesized composites, Co3ZnC/Co@CNTs exhibits the best microwave absorption behavior with a minimum reflection loss (RLmin) of −65.34 dB and an effective absorption bandwidth (EAB) of 5.35 GHz at a low filler content of 15 wt% and a thickness of 2.2 mm. Moreover, using CST to analyze Co3ZnC/Co@CNTs the radar cross section (RCS) was simulated, and the reduction value of RCS was −31.95 dB m2, and effective absorption can achieve full angle coverage. The outstanding microwave absorption capabilities of Co3ZnC/Co@CNTs can be credited to the effective impedance matching, robust interface polarization, and significant conduction loss. This paper also provides a strategy for strengthening the microwave absorption ability of absorbers through the interface engineering.

Infrared photometry and spectrometry of satellites and debris at UKIRT

The characterization of deep space debris poses a significant challenge in Space Domain Awareness (SDA). Multi-color photometry and the resultant color indices offer the potential to rapidly discriminate between debris and intact space objects such as rocket bodies and satellites. These multi-color techniques can also identify anomalous members of objects in certain groups and cue higher fidelity data collections and studies. However, multi-color photometry can be difficult to interpret, as the effects of phase and rotation become conflated with the more fundamental material properties of the satellite. Additionally, the broad astronomical photometric bands may not identify key spectral features that can be diagnostic for SDA applications. With our recent observational campaign we have been able to collect 5-color photometry in the near-IR with WFCAM as well as overlapping near-IR spectra with the UKIRT 1–5 μm Imager-Spectrometer (UIST). On a small set of objects, we also have mid-IR spectrophotometry with the Mid-IR esCHELLE (Michelle) imaging spectrograph.Our previous measurements with the United Kingdom Infrared Telescope (UKIRT) Wide Field Camera (WFCAM) characterized a wide range of space objects with the goal of developing techniques to rapidly discriminate between different classes of objects and to identify anomalous members of these groups. The survey has produced a comprehensive database of 5-color photometry in the Z, Y, J, H, and K bands, analogous to the bands that are anticipated to be exploited by future U.S. ground-based SDA systems. Our current data set includes:(a)United States Centaur rocket bodies (RBs),(b)Molniya communication satellites including the −1 K, 1T, −2, and −3 variants,(c)Russian FREGAT and SL-6 upper stage RBs in Molniya orbits,(d)Russian Breeze-M rocket bodies disposed of in GEO-crossing graveyard like orbits, and the Angara-5/Breeze-M mass simulator, also disposed of in a near-GEO orbit,(e)Intact payloads selected from satellites using the Boeing HS-376 buses—including four different generations of solar panel technology.Many of the objects we have studied have significant orbital inclination or drift in the GEO belt. The interpretation of photometry of these objects is especially difficult as phase angle can no longer be considered simply as a single-dimensional quantity. During 2023, we have endeavored to expand our phase angle coverage of a handful of objects and comprehensively sample brightness and color in both components of phase angle. In this paper we present exemplary “phase-phase” diagrams demonstrating this technique and highlight some of the practical and observational difficulties in achieving comprehensive phase angle coverage and interpreting these results.

Hindfoot Alignment in Flexible Cavovarus Deformity Under Orthostatic and Coleman Block Test Positions: A Weightbearing Computed Tomography Study.

Flexible cavovarus deformity is prevalent and the Coleman block test is frequently used to assess the first ray plantarflexion malpositioning in the overall deformity as well as the flexibility of the hindfoot. The objective was to assess and compare the weightbearing computed tomography (WBCT) 3-dimensional (3D) changes in clinical and bone alignment in flexible cavovarus deformity patients when performing the Coleman block test when compared to normal standing position and to controls. Twenty patients (40 feet) with flexible cavovarus deformity and 20 volunteer controls (40 feet) with normal foot alignment underwent WBCT imaging of the foot and ankle. Cavovarus patients were assessed in normal orthostatic and Coleman block test positions. Foot and ankle offset (FAO), hindfoot alignment angle (HAA), talocalcaneal angle (TCA), subtalar vertical angle (SVA) and talonavicular coverage angle (TNCA) and a CT-simulated soft tissue envelope image, WBCT clinical hindfoot alignment angle (WBCT-CHAA), were evaluated by 2 readers. Measurements were compared between cavovarus nonstressed and stressed positions and to controls. P values of .05 or less were considered significant. The intra- and interobserver intraclass correlation coefficient were good or excellent for all WBCT measurements. Cavovarus patients demonstrated significant correction of WBCT-CHAA (9.7 ± 0.4 degrees), FAO (2.6 ± 0.4%), and TNCA (8.8 ± 1.8 degrees) when performing the Coleman block test (all P values <.0001). However, WBCT-CHAA and FAO measurements were still residually deformed and significantly different from controls (P values of .001 and <.0001, respectively). TNCA values corrected to values similar to healthy controls (P = .29). No differences were observed in cavovarus patients during Coleman block test for the coronal measures: HAA, TCA, and SVA measurements. In this study, we observed improvement in the overall 3D WBCT alignment (FAO), axial plane adduction deformity (TNCA), as well as CT simulated clinical hindfoot alignment (WBCT-CHAA) in flexible cavovarus deformity patients when performing a Coleman block test. However, we did not find improvement in measures of coronal alignment of the hindfoot, indicating continued varus positioning of the hindfoot in these patients.

Determination of the Main Components of the Curvature of the Thread Axis Taking into Account the Deformation of the Section in the Zone of Contact with The Direct

During the research, the main components of the curvature of the axis of the thread were determined, taking into account the deformation of the section in the contact zone with the guide. Irregularity of the geometric dimensions of the cross-section of the thread along the length and the input tension over time significantly affect the value of the tension of the thread after passing through the guide. At the same time, the speed of thread movement is important. When the speed of movement increases, the values of dynamic loads in the zone of interaction of the thread with the cylindrical guide surfaces of large and small curvature, thread guides, increase. The dependences of the output tension of a complex thread or yarn on the radius of curvature of the guide surface of a large curvature are established, taking into account the input tension, the angle of coverage, the type of raw material, the ratio of the radius of the cross section of the thread and the inner radius of the guide, bending stiffness, deformation in the contact zone, nonlinear dependence of the coefficient of friction.

Robust adaptive beamforming for cylindrical uniform conformal array

As we all know, conformal arrays can provide smaller radar cross-section (RCS) and greater angle coverage than conventional linear arrays and planar arrays. In this paper, we develop a robust adaptive beamforming (RAB) approach using the cylindrical uniform conformal array. Firstly, we reconstruct the interference-plus-noise covariance matrix (INCM) by estimating the steering vectors (SVs) and powers of all interferences. Specifically, we estimate the interference SVs by exploiting the MUSIC spectrum and corrected by solving a minimization problem based on the orthogonality between the interferences SVs and noise subspace, and the interferences powers are further estimated by utilizing the non-correlation between different signal SVs. With the reconstructed INCM, the SV of the signal-of-interest is estimated by solving a quadratically constrained quadratic programming problem. Numerical results demonstrate that the proposed approach is obviously superior to the existing RAB techniques.

Correction of progressive collapsing foot deformity classes after isolated arthroscopic subtalar arthrodesis

IntroductionSubtalar osteoarthritis in the context of flatfoot (recently renamed Progressive Collapsing Foot Deformity (PCFD)) may be treated through subtalar joint (SJ) arthrodesis with anticipated consequences on three-dimensional bony configuration. This study investigates the correction of PCFD-related deformities achieved after Anterolateral Arthroscopic Subtalar Arthrodesis (ALAPSTA). MethodsIn this retrospective study, we evaluated pre- and post-operative (at 6 months) weight bearing computed tomography (WBCT) images of patients diagnosed with PCFD with a degenerated SJ (2 A according to PCFD classification) and/or peritalar subluxation (2D) with or without associated flexible midfoot and/or forefoot deformities (1B, 1 C and 1E) which underwent ALAPSTA as a standalone procedure between 2017 and 2020. Multiple measurements were used to assess and compare pre and post-operative PCFD classes. ResultsThirtythree PCFD (33 patients, median age 62) were included in the study. Preoperative medial facet subluxation was 28.3 % (IQR, 15.1 to 49.3 %). Overall PCFD 3D deformity improved with a reduction of the foot and ankle offset from 9.3 points (IQR, 7.8 to 12) to 4 (IQR, 0.9 to 7) (p < 0.001). Class A-hindfoot valgus (median tibiocalcaneal angle and median calcaneal moment arm improved by 9.4 degrees (p < 0.001) and 11 mm (p < 0.001), respectively), class B-midfoot abduction (median talonavicular coverage angle improved by 20.5 degrees, p < 0.001) and class C-forefoot varus (median sagittal talo-first metatarsal angle improved by 10.2 degrees (p < 0.001)) were significantly corrected after surgery. Class D was difficult to assess due to the fusion procedure. No patient had a pre-operative valgus deformity at the ankle (no class E), and no significant change of the talar tilt was observed (p = 0.12). ConclusionIn this series, ALAPSTA performed as a standalone procedure to treat patients diagnosed with PCFD with a degenerated subtalar joint and/or peritalar subluxation was effective not only at correcting hindfoot alignment but also flexible midfoot abduction and flexible forefoot varus. Level of evidenceLevel IV, case series

Elevation Resolution Enhancement Oriented 3D Ultrasound Imaging.

Three-dimensional (3D) ultrasound imaging can be accomplished by reconstructing a sequence of two-dimensional (2D) ultrasound images. However, 2D ultrasound images usually suffer from low resolution in the elevation direction, thereby impacting the accuracy of 3D reconstructed results. The lateral resolution of 2D ultrasound is known to significantly exceed the elevation resolution. By combining scanning sequences acquired from orthogonal directions, the effects of poor elevation resolution can be mitigated through a composite reconstructing process. Moreover, capturing ultrasound images from multiple perspectives necessitates a precise probe positioning method with a wide angle of coverage. Optical tracking is popularly used for probe positioning for its high accuracy and environment-robustness. In this paper, a novel large-angle accurate optical positioning method is used for enhancing resolution in 3D ultrasound imaging through orthogonal-view scanning and composite reconstruction. Experiments on two phantoms proved that our method could significantly improve reconstruction accuracy in the elevation direction of the probe compared with single-angle parallel scanning. The results indicate that our method holds the potential to improve current 3D ultrasound imaging techniques.