Location Of Spurs Research Articles

Automated expert-level scleral spur detection and quantitative biometric analysis on the ANTERION anterior segment OCT system

AimTo perform an independent validation of deep learning (DL) algorithms for automated scleral spur detection and measurement of scleral spur-based biometric parameters in anterior segment optical coherence tomography (AS-OCT) images.MethodsPatients...

The Impact of Spur Site and Foliar Application of Zinc and Boron in some Specifications, of Apples (IBrahimi variety)

Studying the impact of spur location and zinc and boron spraying on certain growth and flowering characteristics and yield of the Ibrahimi apple variety was conducted in one of the private orchards in a city in the Al-Saqlawiyah sub-district, Fallujah district, Anbar governorate, during the seasons 2021 and 2022. Fifty-four trees with rather consistent growth were chosen at the age of five years and planted on plots measuring 4 meters by 4 meters. The trees were sprayed with zinc (ZN0, ZN1) and boron (B0, B1, B2) twice yearly in a factorial experiment with a 3X3X2 RCBD randomized complete block design, where the first factor represents the selection of the spur site and its symbol (S1, S2, S3), the second factor is spraying, and the third factor is spraying. A considerable rise in the investigated characteristics was seen after spraying with the components under investigation (average fruit size, average fruit diameter, percentage of fallen fruits and percentage of remaining fruits).

Effects of Locations of Spur Dyke on Bed and Scour around Bridge Piers in Meandering Channel

Spur dykes are the structures which are used to protect the eroding bank of rivers. They are sometimes also used to safeguard the life of many structures such as bridge piers, abutments etc. The efficiency of spur dykes has been checked in straight channels by conducting model tests in laboratories by many investigators. Very few studies were done in curved channels. In present work an attempt has been made to study the effect of location of spur dyke on bed and scour around bridge pier in curved open channel (bend angle = 80o ) with time. Experiment has been carried out in 80o channel bend at constant discharge (3.5×10–3 m3 /s) and bridge pier is located at angular displacement ϴ = 60o . Here ϴ is the angle the line drawn at the inlet of any bend to the line joining the centre of curvature and any point on the outer portion of the bend. It is found that maximum scouring occurs at ϴ = 0o and 20o along inner wall and at ϴ = 60o and 80o along outer wall. It is also found that scouring around bridge pier is more in the vicinity of pier and decreases with increase in distance from pier. The most suitable location for spur dyke to protect bridge pier is at angular displacement ϴ = 20o . Scour developed rapidly during initial time and then rate of scouring decreases with elapse of time.

Revisiting the Distance to Radio Loops I and IV Using Gaia and Radio/Optical Polarization Data

Abstract Galactic synchrotron emission exhibits large angular scale features known as radio spurs and loops. Determining the physical size of these structures is important for understanding the local interstellar structure and for modeling the Galactic magnetic field. However, the distance to these structures is either under debate or entirely unknown. We revisit a classical method of finding the location of radio spurs by comparing optical polarization angles with those of synchrotron emission as a function of distance. We consider three tracers of the magnetic field: stellar polarization, polarized synchrotron radio emission, and polarized thermal dust emission. We employ archival measurements of optical starlight polarization and Gaia distances and construct a new map of polarized synchrotron emission from WMAP and Planck data. We confirm that synchrotron, dust emission, and stellar polarization angles all show a statistically significant alignment at high Galactic latitude. We obtain distance limits to three regions toward Loop I of 112 ± 17 pc, 135 ± 20 pc, and <105 pc. Our results strongly suggest that the polarized synchrotron emission toward the North Polar Spur at b > 30° is local. This is consistent with the conclusions of earlier work based on stellar polarization and extinction, but in stark contrast with the Galactic center origin recently revisited on the basis of X-ray data. We also obtain a distance measurement toward part of Loop IV (180 ± 15 pc) and find evidence that its synchrotron emission arises from chance overlap of structures located at different distances. Future optical polarization surveys will allow the expansion of this analysis to other radio spurs.

A Design Study of Orthotic Shoe Based on Pain Pressure Measurement Using Algometer for Calcaneal Spur Patients

The pressure pain threshold (PPT) is a useful tool for evaluating mechanical sensitivity in individuals suffering from various musculoskeletal disorders. The aim of this study is to investigate PPT at the heel area in order to assist in the design of orthotic shoes for sufferers of heel pain due to a calcaneal spur. The size and location of the calcaneal spur was determined by x-ray images, with PPT data measured around the spur at five points by using algometer FDIX 25. The pain test experiment was conducted by pressing each point to obtain the pain minimum compressive pressure (PMCP) and its location. The information of shoe size, spur location and dimensions, and the PMCP location for each individual is used to obtain the exact point location for applying a softer material to the shoe in-sole, in order to reduce heel pain. The results are significant as it can be used by designers to design appropriate shoe in-soles for individuals suffering from heel pain.

Automatic Localization of the Scleral Spur Using Deep Learning and Ultrasound Biomicroscopy

PurposeThe purpose of this study was to develop a convolutional neural network (CNN) for automated localization of the scleral spur in ultrasound biomicroscopy (UBM) images of open-angle eyes.MethodsUBM images were acquired, and one glaucoma specialist provided reference coordinates of scleral spur locations in all images. A CNN model based on the EfficientNetB3 architecture was developed to detect the scleral spur in each image. The prediction errors and Euclidean distance were used to evaluate localization performance of the CNN model. Trabecular-iris angle 500 (TIA500) and angle-opening distance 500 (AOD500) were measured and analyzed using the scleral spur locations provided by the specialist and predicted by the CNN model.ResultsThe CNN was developed using a training dataset of 2328 images and tested using an independent dataset of 258 images. The mean absolute prediction errors of CNN model were 48.06 ± 45.40 µm for X-coordinates and 30.84 ± 27.03 µm for Y-coordinates. The mean absolute intraobserver variability was 47.80 ± 44.45 µm for X-coordinates and 29.50 ± 25.77 µm for Y-coordinates. The mean Euclidean distance of the CNN was 60.41 ± 49.02 µm and the intraobserver mean Euclidean distance was 59.78 ± 47.12 µm. The mean absolute error in TIA500 was 1.26 ± 1.38 degrees for all test images and in AOD500 was 0.039 ± 0.051 mm.ConclusionsA CNN can detect the scleral spur on UBM images of open-angle eyes with performance similar to that of a glaucoma specialist.Translational RelevanceDeep learning algorithms for automating scleral spur localization would facilitate the quantitative assessment of the opening of the angle and the risk in angle closure.

Why heel spurs are traction spurs after all

It is unclear whether plantar and posterior heel spurs are truly pathological findings and whether they are stimulated by traction or compression forces. Previous histological investigations focused on either one of the two spur locations, thereby potentially overlooking common features that refer to a uniform developmental mechanism. In this study, 19 feet from 16 cadavers were X-ray scanned to preselect calcanei with either plantar or posterior spurs. Subsequently, seven plantar and posterior spurs were histologically assessed. Five spur-free Achilles tendon and three plantar fascia entheses served as controls. Plantar spurs were located either intra- or supra-fascial whereas all Achilles spurs were intra-fascial. Both spur types consistently presented a trabecular architecture without a particular pattern, fibrocartilage at the tendinous entheses and the orientation of the spur tips was in line with the course of the attached soft tissues. Spurs of both entities revealed tapered areas close to their bases with bulky tips. Achilles and plantar heel spurs seem to be non-pathological calcaneal exostoses, which are likely results of traction forces. Both spur types revealed commonalities such as their trabecular architecture or the tip direction in relation to the attached soft tissues. Morphologically, heel spurs seem poorly adapted to compressive loads.

Deep Neural Network for Scleral Spur Detection in Anterior Segment OCT Images: The Chinese American Eye Study.

PurposeTo develop a deep neural network that detects the scleral spur in anterior segment optical coherence tomography (AS-OCT) images.MethodsParticipants in the Chinese American Eye Study, a population-based study in Los Angeles, California, underwent complete ocular examinations, including AS-OCT imaging with the Tomey CASIA SS-1000. One human expert grader provided reference labels of scleral spur locations in all images. A convolutional neural network (CNN)-based on the ResNet-18 architecture was developed to detect the scleral spur in each image. Performance of the CNN model was assessed by calculating prediction errors, defined as the difference between the Cartesian coordinates of reference and CNN-predicted scleral spur locations. Prediction errors were compared with intragrader variability in detecting scleral spur locations by the reference grader.ResultsThe CNN was developed using a training dataset of 17,704 images and tested using an independent dataset of 921 images. The mean absolute prediction errors of the CNN model were 49.27 ± 42.07 µm for X-coordinates and 47.73 ± 39.70 µm for Y-coordinates. The mean absolute intragrader variability was 52.31 ± 47.75 µm for X-coordinates and 45.88 ± 45.06 µm for Y-coordinates. Distributions of prediction errors for the CNN and intragrader variability for the reference grader were similar for X-coordinates (P = 0.609) and Y-coordinates (P = 0.378). The mean absolute prediction error of the CNN was 73.08 ± 52.06 µm and the mean absolute intragrader variability was 73.92 ± 60.72 µm.ConclusionsA deep neural network can detect the scleral spur on AS-OCT images with performance similar to that of a human expert grader.Translational RelevanceDeep learning methods that automate scleral spur detection can facilitate qualitative and quantitative assessments of AS-OCT images.

Intelligent-assistant system for scleral spur location.

A system based on the use of two artificial neural networks (ANNs) to determine the location of the scleral spur of the human eye in ocular images generated by an ultrasound biomicroscopy is presented in this paper. The two ANNs establish a relationship between the distance of four manually placed landmarks in an ocular image with the coordinates of the scleral spur. The latter coordinates are generated by the expert knowledge of a subject matter specialist. Trained ANNs that generate good results for scleral spur location are incorporated into a software system. Statistical indicators and results yield an efficiency performance above 95%.

End-to-End Direct Digital Synthesis Simulation and Mathematical Model to Minimize Quantization Effects of Digital Signal Generation

Direct digital synthesis (DDS) architectures are becoming more prevalent as modern digital-to-analog converter (DAC) and programmable logic devices evolve to support higher bandwidths. The DDS architecture provides the benefit of digital control but at a cost of generating spurious content in the spectrum. The generated spurious content may cause intermodulation distortion preventing proper demodulation of the received signal. The distortion may also interfere with the neighboring frequency bands. This article presents the various DDS architectures and explores the DDS architecture which provides the most digital reconfigurability with the lowest spurious content. End-to-end analytical equations, numerical and mathematical models are developed to determine the location and power levels of spurs. Afterwards, the analytical equations, numerical and mathematical models are shown to be consistent with the experimental data. A developer can use the information to design a DDS architecture that meets their minimum requirements.

Prediction of Phase Noise and Spurs in a Nonlinear Fractional-${N}$ Frequency Synthesizer

Integer boundary spurs appear in the passband of the loop response of fractional- ${N}$ phase lock loops and are, therefore, a potentially significant component of the phase noise. In spite of measures guaranteeing spur-free modulator outputs, the interaction of the modulation noise from a divider controller with inevitable loop nonlinearities produces such spurs. This paper presents analytical predictions of the locations and amplitudes of the spurs and accompanying noise floor levels produced by interaction between a divider controller output and a PLL loop with a static nonlinearity. A key finding is that the spur locations and amplitudes can be estimated by using only the knowledge of the structure and pdf of the accumulated modulator noise and the nonlinearity. These predictions also offer new insights into why the spurs appear.

Comparison of the trabecular meshwork length between open and closed angle with evaluation of the scleral spur location

This study analysed the trabecular meshwork (TM) length in open and closed angle patients and presented a better method for locating the scleral spur using Schwalbe’s line method in anterior segment optical coherence tomography (AS-OCT). Patients who underwent AS-OCT at Yonsei University Gangnam Severance Hospital we enrolled; 58 and 57 open and closed angle eyes, respectively. We measured the distance from the scleral spur to Schwalbe’s line as the TM length and compared it between open and closed angle patients, and to previous studies. TM length was applied to locate the scleral spur using Schwalbe’s line method. Mean TM lengths were 811 ± 83 μm and 575 ± 96 μm in the open and closed angle groups, respectively (p < 0.001). Comparing the actual TM heights using Schwalbe’s line method with an updated reference distance significantly increased accuracy to locate the scleral spur (open: 811 μm, closed: 575 μm) when compared with the 1000 μm reference distance (p < 0.001). TM length was significantly different between open and closed angle patients. Further, the reference distance for Schwalbe’s line method should be distinguished according to open and closed angle eyes in order that the scleral spur can be located properly.

Prevalence and location of bone spurs in anterior ankle impingement: A cadaveric investigation.

Anterior ankle impingement (AAI) results from repetitive microtrauma leading to pain and decreased dorsiflexion due to spur formation and synovial hypertrophy. Information about the prevalence of anterior spur formation in a large population, and the individual contributions of the talus and tibia to osseous impingement, is limited. A total of 670 ankle specimens from 344 individuals (n = 111 females, n = 233 males) aged 20 to 40 years at the time of death were examined. Matching tibia and talus were opposed and any spurring causing impingement was recorded. Spur locations were measured and ratios calculated to allow for inter-specimen comparison between: (1) medial-to-lateral and anterior-to-posterior spur location versus dimensions of talar neck width, and (2) medial-to-lateral spur location to dimensions of distal anterior tibial width. Differences in spur prevalence in relation to sex, race, height and age were identified by univariant and multivariable statistical analyses. Bony impingement was observed in 21% (n = 72) of specimens, with bilateral involvement in 8% (n = 27). For ankles with AAI, spurs were seen on the talus only in 61%, on the tibia only in 14%, and on both the tibia and talus in 26%. Spurs were significantly more prevalent in males (P = 0.001) and with increasing specimen age (P = 0.002). There were no significant differences related to specimen height or race. Spurs were predominately located on the anterolateral talus (78%) and the anterolateral portion of the distal tibial margin (80%). AAI was present in 21% of young osseous specimens and was significantly more prevalent in males and with increasing specimen age. Clin. Anat. 31:1144-1150, 2018. © 2018 Wiley Periodicals, Inc.

Digital-to-Time Synthesizers: Separating Delay Line Error Spurs and Quantization Error Spurs

This paper analyzes the spurs due to delay line (DL) buffer mismatch errors and phase quantization errors in a digital-to-time conversion (DTC) direct frequency synthesizer. Applying the time/frequency axis scaling property of the Discrete Fourier Transform (DFT) to a close approximation of the general case of both buffer error and quantization error spurs, it is shown that the spur spectra for all possible output frequencies can be divided into a very small number of classes. All the spectra within a class are scaled and systematically re-arranged versions of each other. For a DTC with a phase accumulator with I integer and M fractional bits, this result simplifies the number of spectra from 2(I+M) to M. The condition that allows separation of the buffer errors spur locations from the quantization error spur location is derived. Spurs predicted based on the analysis match closely with actual measurements performed on a 90 nm CMOS DTC synthesizer. The spur analysis also applies to the flying adder (FA) synthesizer.

Split cord malformation with dorsally located bony spur: Report of four cases and review of literature

Split cord malformations (SCM) with a dorsally located bony spur are a very rare entity. The authors report a series of four such cases. The literature is reviewed regarding the pathogenesis and management of this uncommon variant of SCM. The presenting features include – scoliosis with motor and autonomic dysfunction (n = 1), scoliosis with cutaneous patch (n = 1), hypertrichotic area (n = 1), and motor deficits alone (n = 1). The location of spur was thoracic and lumbar in two patients (50%) each. Low-lying conus was present in three patients. Long segment syrinx was present in one patient. With respect to the bony anomalies, two patients had a hypertrophied posterior arch (HPA) and one patient had a dysraphic spine. All patients underwent surgical excision of the spur with detethering, if a low-lying conus was present. Two patients developed transient worsening of the neurological status after surgery which recovered at the time of the last follow-up; in both these patients, there was a HPA and a low-lying conus. Surgical excision of the spur with detethering of filum, in cases of low-lying conus, is the treatment of choice. Risk of post-operative worsening of the neurological status is increased in cases in which there is concomitant presence of HPA.

Comparison of Unenhanced and Enhanced Imaging Protocols for Angle Measurements With Anterior Segment Optical Coherence Tomography

To compare the intraobserver and interobserver agreement of anterior chamber angle measurements using unenhanced and enhanced imaging protocols for anterior segment optical coherence tomography (AS-OCT). Anterior segments of 30 eyes of 15 healthy subjects (mean age: 33.8 ± 13.0 years, 8 women) were imaged by a single examiner with AS-OCT using unenhanced and enhanced imaging protocol. Two masked observers analyzed each image independently on two separate occasions. The reproducibility of angle parameters was estimated by calculating coefficients of variation separately for each observer. Bland-Altman plots were constructed to assess the intraobserver and interobserver agreement. The intraobserver and interobserver reproducibility was similar between imaging protocols. Intra-observer and interobserver agreements were also similar for all parameters evaluated. The best estimate of scleral spur location was determined in all images by both observers. Measurement variability was similar with the unenhanced and enhanced imaging protocol in this series of eyes with open angles.

Novel anterior-chamber angle measurements by high-definition optical coherence tomography using the Schwalbe line as the landmark

ObjectiveTo propose the Schwalbe line (SL) as a new anatomical landmark, independent of the scleral spur (SS) location, for assessing anterior chamber angle (ACA) width quantitatively with high-definition optical coherence...

Spur Model for a Fixed-Frequency Signal Subject to Periodic Jitter

This paper presents an automated algorithm that is capable of predicting both the location and magnitude of spurs that are caused by different sources of jitter on a periodic signal. A practical circuit that produces this kind of jittered periodic signal is the direct digital period synthesis (DDPS) circuit that can be used as a flexible clock source for various applications such as adjusting a sampling rate in a measurement and signal processing. Points of interest with clocks that are subject to periodic perturbations are their spectral purity and jitter characteristics. Our algorithm is applied to the DDPS to greatly reduce the simulation time that is needed to accurately compute the spectrum of the signal and its spurious frequency content. The method is used to explore how the operating parameters of the DDPS influence the spectral purity of its output. The generic analysis method that has been used in this paper can be transposed to fractional-N synthesizers, delay-line-based direct digital synthesizers, or serializers.

Assessment of the Scleral Spur in Anterior Segment Optical Coherence Tomography Images

To assess visibility of the scleral spur in anterior segment optical coherence tomography (AS-OCT) images. This cross-sectional observational study included 502 participants aged 50 years or older who had no previous ophthalmic problems and were recruited from a community clinic in Singapore. All participants underwent gonioscopy and AS-OCT (Visante; Carl Zeiss Meditec, Dublin, California). Scleral spur location was assessed in AS-OCT images by 2 examiners with glaucoma subspecialty training and was defined as the point where there was an inward protrusion of the sclera with a change in curvature of its inner surface. Scleral spur location could be determined in 72% of the images of the right eye. Its location on AS-OCT images was less detectable in quadrants with a closed angle on gonioscopy and also in images obtained in the superior and inferior compared with the nasal and temporal quadrants (64%, 67%, 75%, and 80%, respectively; P < .001). The inability to detect the scleral spur may hamper quantitative analysis of anterior chamber angle parameters that are dependent on the location of this anatomical structure, particularly in the superior and inferior quadrants. New parameters independent of the scleral spur may be useful for detecting eyes at risk of angle closure.

The coracoacromial ligament: Morphology and study of acromial enthesopathy

The coracoacromial ligament (CAL), normally a superior restraint against humeral translation, is frequently involved in rotator cuff impingement pathology. However, surgical excision of the CAL is not always clinically successful. Little anatomic information exists about the morphology and function of this ligament. The CAL and glenohumeral joint in 56 cadaveric shoulders were examined in 31 cadavers. Nineteen dimensional parameters were obtained by direct measurement. In 16 shoulders, specific attention was directed at the anterior band of the CAL. Variation exists in the morphology of the CAL. The most common configuration of the CAL was two distinct ligamentous bands that could be classified anatomically as an anterolateral band (ALB) and posteromedial band (PMB). The ALB commonly extended to the posterolateral aspect of the acromion. Furthermore, it frequently extended anterolaterally to the acromion, ending in a coracoacromial falx. Spur formation had occurred in 10 of 16 shoulders evaluated and always appeared in the ALB. Spur formation in the ALB correlated with a focal CAL that was narrower, less divergent, shorter, and thicker than a diffuse CAL that did not have a spur. The mean angle of diversion between the ALB and PMB, when a spur was present, was 31 degrees compared with 45 degrees when no spur was present. CAL band thickness varied, with the ALB being thicker at the acromion than at the coracoid and the PMB being thicker at the coracoid than at the acromion. During arthroscopic subacromial decompression, failure to visualize the anterolateral corner of the acromion adequately may result in incomplete resection of the CAL, especially if the PMB is mistaken to be the entire ligament. Incomplete removal of the CAL may be a factor in clinical failures of arthroscopic subacromial decompression. The preferential location of spurs in the ALB suggests that it is a major load-bearing structure. Furthermore, the ALB is thicker at the acromion, suggesting increased strain. Our data suggest that a possible function of the CAL is to dampen stress on the acromion from muscle activity.