Absolute Angle Research Articles

Effects of acute metaphedrone exposure on the development, behaviour, and DNA integrity of zebrafish (Danio rerio)

The presence of new psychoactive substances (NPS), like metaphedrone (3-MMC), in aquatic environments raises concern about the potential negative effects on ichthyofauna. Therefore, the aim of this study was to evaluate the potential effects of 3-MMC on zebrafish embryonic development, behaviour, and DNA integrity. For that, embryos were exposed during 96 h post-fertilization to 3-MMC (0.1, 1, 10, and 100 µg/L). Overall, an increase in the eye area of zebrafish larvae was observed for the concentrations of 1 μg/L (increase of 24%) and 100 μg/L (increase of 25%) in comparison with the control group. Genetic damage was noted at the highest concentration (100 µg/L) with an increase of DNA damage (increase of 48%) and hyperactivity and disorganised swimming pattern characterised by an increase in speed (increase of 49%), total distance moved (increase of 53%), and absolute turn angle (increase of 48%) of zebrafish larvae. These findings pointed that, at environmental low levels, 3-MMC harmful effects are not expected to occur during critical development life stages of fish.Graphical

Effects of different handling methods on the behavior of adult zebrafish

The zebrafish is an important biomedical research organism. In most research, zebrafish are removed from their home tank and subsequently their phenotype is measured. The method of handling the fish, however, may significantly affect a variety of phenotypes. This is particularly problematic for studies of brain function that measure behavioral or neuronal responses. Nevertheless, the potential effects of handling have not been analyzed, and in fact are usually ignored. Here, we explore the effects of two usual and two rarely or never-before employed handling methods on the behavior of adult zebrafish. We exposed each fish to one of four handling methods, a between subject experimental design: (1) net chasing followed by air-suspension, (2) gentle net catching (without chasing) followed by air-suspension, (3) gentle net catching followed by being placed in a beaker (no chasing and very short air-suspension), (4) transportation in home tank and pouring the fish directly into the test tank (no chasing, netting or air-suspension). With these handling methods, the fish were placed in a test tank and their swim path was videorecorded and analyzed. Handling significantly affected swim path parameters, duration and frequency of immobility, absolute turn angle and its temporal variance and velocity, but not the distance to bottom. The behavioral effects confirmed that chasing and netting induce robust behavioral changes, and that pouring the fish from its home to its test tank is least aversive for zebrafish. We recommend using this latter method to reduce experimental error variation and increase reproducibility of results.

Aftershock fragility assessment of steel gabled frames consisting of web-tapered members

Due to the widespread construction of steel gabled frame systems throughout the world, many of them are located in regions with high seismicity and experience sequential strong events in the future. Previous studies have clearly shown that the damage caused by the mainshock modifies the overall strength and stiffness and consequently dynamic response to the aftershock. However, the current structural design process only considers the main seismic event, and the post-mainshock scenarios and their effects are generally ignored. In order to address this issue, in the present study, the mainshock incremental dynamic analysis (IDA) was first conducted on four SGFs. Then mainshock damage states based on the transient absolute maximum drift angle were considered, and aftershock incremental dynamic analysis analysis was performed on the mainshock-damaged structures. Aftershock fragility curves using probabilistic seismic demand models for transient absolute maximum drift angle and median IDA curves for residual absolute maximum drift angle were developed to compare intact and pre-damaged SGFs. The results showed that aftershocks significantly increase the vulnerability of short-period SGFs when higher damages are induced during mainshock, where the aftershock collapse capacity is reduced by up to 13% for the largest mainshock damage state. It was also found that in terms of aftershock collapse capacity associated with the residual absolute maximum drift angle, long-period SGFs require major realignment while short-period SGFs cannot be repaired.

Receiver orientation and event back-azimuth estimation for downhole microseismic monitoring using a probabilistic method based on P-wave polarization

Microseismic event back-azimuth is an indispensable parameter for source localization in downhole microseismic monitoring, and the accurate orientation of horizontal components of downhole seismic receivers is vital for reliably determining the event back-azimuth. Variation in the monitoring data quality may jeopardize the accuracy of receiver orientation which will further affect the event back-azimuth estimation. To mitigate this issue, we proposed a new probabilistic method based on P-wave polarization analysis for receiver orientation and event back-azimuth estimation. The algorithm constructs the von Mises distribution function using the polarization angle and corresponding rectilinearity of the P-wave, then determines the target angle using the maximum of the probability function. The receiver having the highest rectilinearity from the active-source event is used to quantify a reliable absolute orientation angle, and the relative orientation angles are calculated by the probability distributions based on the measurement angle differences and the associated averages of rectilinearity from all events. After receiver orientation, the P-wave polarization angles with different rectilinearity values are applied to construct the probability distribution functions to estimate the event back-azimuths. By using high-quality events and multi-receiver recordings, our methodology can greatly reduce the unintentional error in receiver orientation and increase event back-azimuth accuracy. We investigate the feasibility and reliability of the proposed method using both synthetic and field data. The synthetic data results demonstrate that, compared to the conventional methods, the proposed method can minimize the variance of the receiver orientation angle and back-azimuth estimation. The weighted standard deviation analysis demonstrates that the proposed method can reduce the orientation error and improve the event back-azimuth accuracy in the field dataset.

Comparison of fit and trueness of zirconia crowns fabricated by different combinations of open CAD-CAM systems.

This study aims to clinically compare the fitness and trueness of zirconia crowns fabricated by different combinations of open CAD-CAM systems. Total of 40 patients were enrolled in this study, and 9 different zirconia crowns were prepared per patient. Each crown was made through the cross-application of 3 different design software (EZIS VR, 3Shape Dental System, Exocad) with 3 different processing devices (Aegis HM, Trione Z, Motion 2). The marginal gap, absolute marginal discrepancy, internal gap(axial, line angle, occlusal) by a silicone replica technique were measured to compare the fit of the crown. The scanned inner and outer surfaces of the crowns were compared to CAD data using 3D metrology software to evaluate trueness. There were significant differences in the marginal gap, absolute marginal discrepancy, axial and line angle internal gap among the groups (P < .05) in the comparison of fit. There was no statistically significant difference among the groups in terms of occlusal internal gap. The trueness ranged from 36.19 to 43.78 µm but there was no statistically significant difference within the groups (P > .05). All 9 groups showed clinically acceptable level of marginal gaps ranging from 74.26 to 112.20 µm in terms of fit comparison. In the comparison of trueness, no significant difference within each group was spotted. Within the limitation of this study, open CAD-CAM systems used in this study can be assembled properly to fabricate zirconia crown.

Variability of gait characteristics in lameness elephant.

Lameness has a significant impact not only on the economy but also on elephant welfare. Several gait characteristics are altered to compensate for the discomfort. The traditional approach to detecting lameness has relied on mahout and veterinarian observation. The study aimed to determine how lameness affected the variability of an elephant's gait by using a three-dimensional inertial measurement unit (IMU) with Wi-Fi sensors. Five elephants with lameness, as determined by an experienced veterinarian and two, non-lamed elephants, aged between 58-80 years were included in the study. Gait biomechanics including limb segment motion, obtained from individually gyrometric- and accelero-based parameters and demonstrated as a graphical pattern showing changes in absolute rotation angle over time. The result revealed some character changes in gait kinematics parameters, but it was heterogeneity with an inconclusive pattern. The interlimb coordination could be a part of maintaining the actual locomotion pattern, or it could be a result of the mild degree of lameness for which all of the clients have compensated. This study introduces a new objective method for quantifying gait changes caused by lameness, additional research is required to make this objective more clinically applicable.

Absolute Two-Tracked Optical Rotary Encoders Based on Vernier Method

Driving synchronous machines requires early and accurate knowledge of the absolute position of the rotor; current solutions based on resolvers, sin–cos, or absolute encoders are complex, bulky, and costly. Hence, in this work two variants of absolute rotary encoder based on the Vernier method are analyzed. One, already discussed in the literature, displays the Vernier scale across the whole circumference (full-Vernier), and the other shows half Vernier traces over the entire perimeter (half-Vernier), which is an original feature. Both the implementations are characterized by only two tracks and as many sensors: the proposed conditioning algorithms provide the absolute angular position as a function of the time delays between the wave edges generated by the two traces, thus being of easy implementation on low-cost microcontroller units (MCUs). The Vernier encoders are also compared with the state-of-the-art absolute and relative solutions, i.e., incremental, binary, and Gray-code encoders. Experimental tests are carried out to assess the accuracy of the proposed sensors. The investigation shows that: 1) the full-Vernier cannot provide, in practice, a reliable estimate of the direction of rotation and of the actual angular sector without resorting to a third sensor; 2) the half-Vernier produces a trusty measurement of the absolute angle and velocity; and 3) can give a reliable position result with less than 30° shaft turn, but it can suffer from marginal performance degradation at low velocities in conjunction with high accelerations. Compared with the Gray encoder, the half-Vernier provides a simpler and more compact hardware for a given resolution, similar to that of an incremental encoder, at the expense of a small accuracy reduction at low speed.

ПОБУДОВА АВТОМАТИЗОВАНОЇ СИСТЕМИ АУДІОЛОКАЦІЇ ЗАГРОЗ

The article discusses the process of building a system for finding the direction of a sound source using the finite difference method for processing digitized sound signal data. The finite difference method has been modified by using the cross-correlation function which simplifies the processing of the digitized signal due to the improvement of the calculation algorithm and the transition from the differential to the numerical format of the input data which significantly reduces the number of calculations and simplifies them. Statistical processing of the obtained results is proposed to reduce the error of finding the absolute angle to the software-generated sound source. The software was developed which enables the computer implementation of the audio location system based on the principles of object-oriented programming. It uses digitized signal data for calculations and modeling of the results of the algorithm. The program was created on the Windows OS platform in the Windows Studio environment in compliance with object-oriented programming paradigms. The use of the modified algorithm by the authors in the process of software implementation of the sound-metric system made it possible to analyze the operation of the method and develop receiver configurations that allow increasing the accuracy of the results. Experimental (laboratory) studies of the developed system under the condition of using a configuration justified by the authors and statistically processed data, made it possible to obtain results of searching the direction of the sound source with an error of less than 1o. The main scientific result of the conducted research is the improvement of data processing algorithms for audio-location search which, unlike existing approaches, allows to increase the accuracy of such a process based on the application of the mutual correlation function and its subsequent mathematical adjustment. The practical value of the obtained results is an easy adaptation of the sound-metric system developed and tested in laboratory conditions for operation in military field conditions.

축류펌프의 입구 안내깃 모사에 따른 성능 및 내부 유동장에 관한 수치해석적 연구

In this study, an absolute flow angle was numerically assigned to the inlet of an axial pump in order to predict its performance and internal flow field prior to the design process of an inlet guide vane. The finite volume method, which is an approximate analysis method based on the three-dimensional Reynolds-averaged Navier-Stokes (RANS) equation, was applied for discretization of governing equations. The shear stress transport (SST) model was used as the turbulence model and the hexahedral grid system was selected as the appropriate number of nodes through the grid dependency test. The change in the performance curve and internal flow field was found with respect to the difference in the absolute flow angle at the impeller inlet. When installing a variable inlet guide vane of an axial flow pump, an efficient operation plan by adjusting the angle of an inlet guide vane might be established with the results of this study.

Study on the Multiperiod Bipolar Inductive Absolute Angle Sensor

In this study, a novel design of multiperiod bipolar inductive absolute angle sensor is proposed. The sensor structure is composed of stator and rotor. An inner and outer fan-shaped bipolar pattern is designed and fabricated on the rotor. The receiving coils and signal processing circuits are on the stator. When alternating current is applied to the excitation coil, the eddy current is generated in the rotor. The induced voltage of two adjacent receiving coils is in the form of cosine, when the rotor rotates above the receiving coil. There are two groups of receiving coils in the sensor. One group is composed of eight loops, corresponding to the 45° fan-shaped pattern at the outer edge, and the other group is composed of two loops, corresponding to the 180° fan-shaped (semicircular) pattern at the center. The coil with more loops provides high measurement accuracy and the coil with a small number of loops provides the identification of the number of cycles. The results show that the measurement error is 0.04° and the resolution is better than 0.005° in the range of 0°–360°. Through the multiperiod bipolar pattern proposed in this article, a high accuracy absolute position measurement can be realized.

Three-dimensional micro-structurally informed in silico myocardium-Towards virtual imaging trials in cardiac diffusion weighted MRI.

In silico tissue models (viz. numerical phantoms) provide a mechanism for evaluating quantitative models of magnetic resonance imaging. This includes the validation and sensitivity analysis of imaging biomarkers and tissue microstructure parameters. This study proposes a novel method to generate a realistic numerical phantom of myocardial microstructure. The proposed method extends previous studies by accounting for the variability of the cardiomyocyte shape, water exchange between the cardiomyocytes (intercalated discs), disorder class of myocardial microstructure, and four sheetlet orientations. In the first stage of the method, cardiomyocytes and sheetlets are generated by considering the shape variability and intercalated discs in cardiomyocyte-cardiomyocyte connections. Sheetlets are then aggregated and oriented in the directions of interest. The morphometric study demonstrates no significant difference (p>0.01) between the distribution of volume, length, and primary and secondary axes of the numerical and real (literature) cardiomyocyte data. Moreover, structural correlation analysis validates that the in-silico tissue is in the same class of disorderliness as the real tissue. Additionally, the absolute angle differences between the simulated helical angle (HA) and input HA (reference value) of the cardiomyocytes (4.3°±3.1°) demonstrate a good agreement with the absolute angle difference between the measured HA using experimental cardiac diffusion tensor imaging (cDTI) and histology (reference value) reported by (Holmes et al., 2000) (3.7°±6.4°) and (Scollan etal. 1998) (4.9°±14.6°). Furthermore, the angular distance between eigenvectors and sheetlet angles of the input and simulated cDTI is much smaller than those between measured angles using structural tensor imaging (as a gold standard) and experimental cDTI. Combined with the qualitative results, these results confirm that the proposed method can generate richer numerical phantoms for the myocardium than previous studies.

Ochratoxin A induces locomotor impairment and oxidative imbalance in adult zebrafish.

Ochratoxin A (OTA) is a mycotoxin produced by species of filamentous fungi widely found as a contaminant in food and with high toxic potential. Studies have shown that this toxin causes kidney and liver damage; however, data on the central nervous system effects of exposure to OTA are still scarce. Thus, this study aimed to investigate the effects of exposure to OTA on behavioral and neurochemical parameters in adult zebrafish. The animals were treated with different doses of OTA (1.38, 2.77, and 5.53 mg/kg) with intraperitoneal injections and submitted to behavioral evaluations in the open tank and social interaction tests. Subsequently, they were euthanized, and the brains were used to assess markers associated with oxidative status. In the open tank test, OTA altered distance traveled, absolute turn angle, mean speed, and freezing time. However, no significant effects were observed in the social interaction test. Moreover, OTA also increased glutathione peroxidase (GPx), glutathione-S-transferase (GST), and glutathione reductase (GR) levels and decreased non-protein thiols (NPSH) levels in the zebrafish brain. This study showed that OTA can affect behavior and neurochemical levels in zebrafish.

Importance of Lower Extremity Muscle Performance and Knee Proprioception During First 60 Degrees of Knee Flexion at Three Months After Anterior Cruciate Ligament Reconstruction

Background: Knee proprioception and neuromuscular control may be important factors contributing to re-injury occurrences. Objectives: To examine lower extremity muscular performance and knee proprioception preoperatively and 3 months after anterior cruciate ligament (ACL) reconstruction. Methods: Twelve participants underwent ACL reconstruction using the hamstring tendon. All participants were assessed for knee proprioceptive sense using an isokinetic dynamometer at 15° and 60° of knee flexion. Lower extremity muscular performance was examined using the single-leg squat test (SLS) with two-dimensional motion analysis in frontal and sagittal planes. Results: Mean absolute error angle at a 15-degree-target angle was significantly lower at three months after ACL reconstruction compared with the preoperative state (P = 0.04). Maximal knee flexion angle of the injured The SLS test showed a lesser knee flexion angle of the injured knee at three months after ACL reconstruction (P = 0.01), and injured knee proprioception at 60 degree-flexion did not significantly improve at the three month-postoperative stage. Conclusions: At three months after ACL reconstruction by hamstring graft tendon, knee proprioceptive sense at an inner range of knee extension improved. However, proprioception at the middle range did not significantly develop. The range of hip and knee motions using SLS related to strength changes that the knee extensor needs to improve, especially in the middle range.

Effect of keratometric astigmatism on visual outcomes following small incision lenticule extraction.

To investigate the influence of keratometric astigmatism on visual outcomes following small incision lenticule extraction (SMILE). Eighty eyes undergoing SMILE for myopia correction were classified into two groups based on preoperative keratometric astigmatism: low keratometric astigmatism (LA) and high keratometric astigmatism (HA) groups. Refractive outcomes, vector components, and changes in higher order aberrations (HOAs) were evaluated preoperatively and 6 months postoperatively. At the postoperative 6-month visit, no significant difference was observed in the decentered distance between the HA and LA groups (HA: 0.17 ± 0.08 mm, LA: 0.16 ± 0.08 mm, P = 0.189). No significant differences in the correction index (P = 0.481), absolute angle of error (P = 0.104), or index of success (P = 0.147) were observed between the two groups. There was no significant difference in the induction of corneal aberrations between the two groups. Furthermore, there were no significant associations between the decentered distance and the vector components of astigmatic correction or induction of higher-order aberration in the HA group (P ≥ 0.294, P ≥ 0.112) or the LA group (P ≥ 0.323, P ≥ 0.080). SMILE for high keratometric astigmatism could achieve comparable treatment centration and visual quality to that of low keratometric astigmatism.

Distorted body schema after mastectomy with immediate breast reconstruction: a 4-month follow up study.

BackgroundAfter breast cancer, some patients report residual pain-related upper limb disability without physical impairment. Although pain and altered proprioception are known to affect the working body schema (WBS), there is little available evidence investigating the WBS of breast cancer survivors (BrCS). WBS—body representations in the brain—affect the “neuromatrix” that modulates pain sensitivity and the threshold for threatening stimuli. The aim of this study was to investigate whether WBS was disrupted after mastectomy with immediate breast reconstruction (IBR) for breast cancer and whether pain and proprioceptive changes affected WBS.MethodsThirty-five BrCS participated in the 4-month follow-up study. They were observed at 1 and 4 months postoperatively. The main outcome measures were the left right judgement test (LRJT) results, absolute angle error, pectoralis minor length index (PMI), pain, and Quick-Disabilities of the Arm, Shoulder, and Hand (Q-DASH) score. They were measured at each observation, and parametric tests were performed to identify the nature of WBS.ResultsBoth the reaction time and accuracy of the hand LRJT were poorer than those of the foot and back LRJT (p < 0.001). The hand LRJT reaction time and accuracy were unchanged over the total follow-up period (p = 0.77 and p = 0.47, respectively). There was a weak correlation between the LRJT reaction time and PMI (r = −0.26, p = 0.07), pain severity (r = 0.37, p = 0.02), and Q-DASH score (r = 0.37, p = 0.02). There was also a weak correlation between LRJT accuracy and Q-DASH score (r = −0.31, p = 0.04). The LRJT accuracy of BrCS who underwent surgery on their dominant side was higher than that of BrCS who underwent surgery on their non-dominant side (p = 0.002). Regression analysis found a weak but significant relationship between the early hand LRJT results and late pain severity (adjusted R2 = 0.179, p = 0.007). A similar relationship was found between early hand LRJT results and Q-DASH score (adjusted R2 = 0.099, p = 0.039).ConclusionTo the best of our knowledge, this is the first study providing the nature of WBS after mastectomy with IBR. In this population, it is necessary to postoperatively preserve WBS integrity for pain and upper limb disability.

Influences of main design parameters on the aerodynamic performance of a micro-radial inflow turbine

The micro-radial inflow turbine (MRIT) is not only an important component of a micro-gas turbine but also the core part of a vehicle exhaust gas turbocharger and a small-scale organic Rankine circulatory system. Therefore, designing an MRIT with good performance is of great importance. The values of some main turbine design parameters can significantly influence its aerodynamic performance and structural size. In accordance with the structural characteristics of an MRIT, the relationships between the aerodynamic performance of a turbine and the absolute flow angle at the rotor inlet, the relative flow angle at the rotor outlet, the nozzle and rotor blade velocity coefficients, the ratio of the wheel diameter, velocity ratios, and the degree of reaction were examined. This was done through theoretical analysis combined with experience in the design of a conventional radial inflow turbine. On this basis, the influencing laws and degrees of the seven main design parameters on the aerodynamic performance of an MRIT during aerodynamic design were analyzed. The selection principles of these main design parameters were also summarized. The reasonableness of the above-mentioned selection principles was verified through an aerodynamic design case study of an MRIT combined with a 3D numerical simulation. It was found that the 3D numerical simulation results agreed well with the 1D aerodynamic design. The summarized selection principles of the main design parameters can provide a reference for the successful aerodynamic design of an MRIT.

On Choosing the Optimal Impeller Exit Velocity Triangles in Preliminary Design

Abstract Impeller discharge flow plays an important role in centrifugal compressor performance and operability for two reasons. First, it determines the work factor and relative diffusion for the impeller. Second, it sets the flow into the downstream stationary diffusion system. The choice made in the preliminary design phase for the impeller exit velocity triangle is crucial for a successful design. The state-of-the-art design approach for determining the impeller exit velocity triangle in the preliminary design phase relies on several empirical guidelines, i.e., maximum work factor and diffusion ratio for an impeller, the optimal range of absolute flow angle, etc. However, as modern compressors continue pushing toward higher efficiency and higher work factor, this design approach falls short in providing exact guidance for choosing an optimal impeller exit velocity triangles due to its empirical nature as well as the competing mechanism of the two trends. In light of this challenge, this paper introduces a reduced-dimension, deterministic approach for the design of the impeller exit velocity triangle. The method gauges the design of the impeller exit velocity triangle from a different design philosophy using a relative diffusion effectiveness parameter and is validated using six impeller designs, representative of applications in both turbochargers and aero engines. Furthermore, with the deterministic method in place, optimal impeller exit velocity triangles are explored over a broad design space, and a one-to-one mapping from a selection of impeller total-to-total pressure ratios and backsweep angles to a unique optimal impeller exit velocity triangle is provided. This new approach is demonstrated, and discussions regarding the influences of impeller total-to-total pressure ratio, isentropic efficiency, and backsweep angle on the optimal impeller exit velocity triangle are presented.

Femtosecond laser-assisted arcuate keratotomy for the management of corneal astigmatism in patients undergoing cataract surgery: Comparison with conventional cataract surgery.

PurposeTo assess the effects of femtosecond laser arcuate keratotomy with femtosecond laser-assisted cataract surgery in the management of corneal astigmatism, compared with conventional phacoemulsification cataract surgery.DesignRetrospective comparative interventional case series.MethodsA total of 2,498 eyes of consecutive patients who presented with 3.00 diopters (D) or under of astigmatism were included. The patients were treated with conventional phacoemulsification cataract surgery (conventional group) and femtosecond laser arcuate keratotomy with femtosecond laser-assisted cataract surgery (femtosecond group).ResultsSurgically induced astigmatism (SIA) was higher in the femtosecond group than the conventional group (0.215, p < 0.001). Difference vector (DV) was lower in the femtosecond group (-0.136, p < 0.001). The cut-off value of the overcorrection in the femtosecond group was 0.752 D of target induced astigmatism (TIA). For patients with TIA 0.75 D or under, DV and the value of index of success (TIA into DV) were significantly higher in the femtosecond group (p = 0.022 and < 0.001). The overcorrection ratios were 48.8% in the conventional and 58.9% in the femtosecond group. (p < 0.001). For patients with TIA over 0.75 D, SIA and correction index (TIA into SIA) was higher in femtosecond group (0.310 and 0.250, p < 0.001 and < 0.001, respectively). Absolute angle of error was 20.612 ± 18.497 in the femtosecond group and higher than the conventional group (2.778, p = 0.010).ConclusionFemtosecond laser arcuate keratotomy in cataract surgery was effective in SIA between 0.75 to 3.00 D of corneal astigmatism. However, the overcorrection in the lower astigmatism and angle of error in the higher astigmatism were due to the postoperative corneal astigmatism not decreasing as much as SIA. Overcoming these challenges will lead to better management of corneal astigmatism.

Efficiency optimized axial flow compressor stage with a given shape of flow-path

Performance improvement and optimization for Brayton cycle plants include mainly two aspects: one concerns thermodynamic cycle parameters, another concerns component parameters. As one aspect of the power plant optimizations, parameter optimization is an important design practice for performance improvement of axial flow compressor stage (AFCS). Stagnation isentropic efficiency (IEFF) optimization of AFCS is studied preliminarily by using 1-D flow theory. Optimization design model of AFCS with a given shape of flow-path is provided. Five parameters are taken as design variables, including absolute exit and inlet angles of rotor, absolute exit angle of stator, and relative air densities at exit and inlet stations of stator. Energy balance equations for 1-D flow are constraints. Analytical relations about stagnation IEFF and design variables of the AFCS are obtained. Numerical calculations are performed for a constant mean-diameter AFCS. The results illustrate influences of various fixed design parameters on the optimum stagnation IEFF of the AFCS. The results illustrate that optimal stagnation IEFFs with three fixed input parameter combinations of work coefficient and flow coefficient increase 0.78%, 5.15%, and 5.66% than that of reference plan, respectively; optimal stagnation IEFFs increases with increase of work coefficient and decrease of flow coefficient.

A Novel Method of Quantifying Retinal Displacement Using Ultra-Widefield Fundus Autofluorescence Imaging

To introduce a novel method of quantifying retinal displacement in three dimensions (3D) using ultra-widefield fundus autofluorescence (UWF-FAF). Prospective clinical cohort study. Patients with primary macula-off rhegmatogenous retinal detachment (RRD) treated with pneumatic retinopexy (PnR) or vitrectomy were included. Masked graders selected corresponding points on retinal vasculature and retinal vessel printings (RVPs) within Zone 1, a circular region centered on the fovea with a radius extending to the optic disc (OD) center. Two-dimensional (2D) UWF-FAF was projected to 3D using OD and foveal coordinates. Vertical, horizontal, and diagonal distances between corresponding vessel and RVPs were calculated. Vector displacement of the RVPs to vessels were averaged. A total of 170 retinal vessel-RVP pairs were identified from 54 UWF-FAF images. Mean displacement in Zone 1 was 0.36 ± 0.38 mm, with an absolute mean angle of displacement of 94.93 ± 41.48° and directionality of 191.84 ± 97.39°. Mean Zone 1 displacement was 0.44±0.42mm and 0.21 ± 0.27 mm in vitrectomy (n=35) and PnR (n=19) eyes, respectively (P=.041), with no differences in mean angle of displacement/directionality. A novel method of quantifying the magnitude and direction of retinal displacement is presented, accounting for the spherical 3D curvature of the eye by using corresponding points on retinal vessels and RVPs using UWF-FAF. This provides a 3D vector of displacement agnostic of a singular fixation point such as the optic disc. Accurately quantifying the magnitude and angle/direction of displacement may allow for a better understanding of the mechanisms involved in retinal displacement in various surgical techniques, and a better assessment of the association with functional outcomes.