Degree Of Movement Research Articles

Effect of geometric variations on the wing rock of blended wing-body aircraft

Blended wing-body configurations are anticipated to dominate future transport and military aerospace designs. The departure of the conventional tube-wing configuration has opened several areas of investigation. These designs are susceptible to lateral instability during landing, takeoff, and maneuvering flight despite having improved aerodynamics because of their tailless nature. One of these instabilities, Wing-Rock, poses significant performance and operational difficulties and can potentially cause crashes. Though experimental and numerical studies of the aerodynamics and stability of blended wing-body configurations have been conducted, wing-rock characteristics still need to be identified in the literature. This research aims to investigate these characteristics at low subsonic speeds with varying outboard sweep and geometric twist angles. The study includes a numerical approach based on the rigid body free-vibration method in single roll degree of motion, which uses three-dimensional unsteady Reynolds’ Average Navier Stokes equations, and an analytical approach based on the multiple time scale method, which captures the crucial aspect of the wing rock system. The findings show that the geometrical parameters significantly impact the wing rock characteristics, which are unique to such novel tailless designs.

Seismic response study of multi-span continuous beam bridges near faults considering permanent displacement attenuation effects

The fling-step effect caused by near-fault ground motion induces a step-like permanent displacement of the ground surface, which decays sharply with increasing fault distance, leading to varying degrees of ground motion at each supporting point of the bridge structure. In this context, multi-span long-span bridges exhibit echelon displacement of the main beam and a more complex internal force response compared to ordinary bridges. To investigate the seismic response characteristics of multi-span long-span continuous girder bridges under near-fault ground motion, this study is based on the permanent displacement attenuation model. The main bridge of the Hongyazi Yellow River Bridge in Shizuishan City, consisting of 16 spans, is taken as the research object. Using OpenSees software, a finite element model for the dynamic analysis of the multi-span long-span continuous girder bridge was established, and its structural dynamic characteristics were compared with the natural vibration test of the actual bridge. Based on simulated ground motions that consider the permanent displacement attenuation effect and spatial variability, the seismic response of the key components of the near-fault multi-span long-span continuous beam bridge is examined. The results indicate that under near-fault ground motion considering the attenuation effect of permanent displacement, the main girder of multi-span long-span bridges frequently deviates from the axis in different directions, ultimately resulting in residual deformation of the main girder post-earthquake. The permanent displacement attenuation effect increases the maximum bending moment response at the pier bottom and causes uneven internal force distribution in the bridge. Ignoring this effect can lead to overestimation of bearing deformation.

Surgical Treatment of Periarticular Distal Radius Fracture in Elderly: A Systematic Review

Background/Objectives: The treatment of periarticular distal radius fractures remains challenging. Different surgical treatment options have been proposed as alternatives to conservative treatment. This systematic review aims to compare the functional outcomes, radiological outcomes, and complications among volar locking plates (VLPs), Kirschner-wire fixations, and external fixations (EFs) for distal radius fractures in patients aged 60 years and older. Methods: We conducted a comprehensive search of PubMed, Cochrane, and Science Direct databases assessing the effects of VLP, EF, and K-wire treatments for distal radius fractures in patients aged 60 years and over. The primary outcome was the evaluation of the range of motion (ROM) degrees after three surgical procedures, trying to assess the best treatment option. The secondary outcome included evaluation of the Disabilities of the Arm, Shoulder, and Hand (DASH) score, quick-DASH score, Patient-Rated Wrist Evaluation (PRWE) score, Visual Analog Scale (VAS) score, grip strength, radiographic assessment, and complications comparing VLPs, EFs and K-wires. Results: A total of 23 studies were included, comparing VLP, EF, and K-wire fixation. The overall population comprised 5618 patients, with 4690 females and 1015 males, of which 4468 patients were treated with VLP, 503 with EF, and 647 with K-wire. The most common complications among the VLP group were complex regional pain syndrome (7.5%) and carpal tunnel syndrome (6.8%); for the EF group, infections (9.8%) and carpal tunnel syndrome (6.8%); and for the K-wire group, carpal tunnel syndrome (7.5%) and infections (6.9%). Conclusions: VLP showed better clinical outcomes in the first few months after treatment. However, these differences decreased over time and became similar after one year. EF and K-wire fixations remain easier to manage during surgery.

Pangoniometry is a modern method of physiological and hygienic assessment of the severity of work according to the indicator "Working posture"

Introduction. The development of occupational health is largely ensured by its comprehensive approach to the study of the "Man–machine–production environment" system, which includes an assessment of many factors characterizing the production system in the action shaping working conditions. However, in the concept of "Working conditions" they are "a set of factors in the working environment and the labor process that influence the performance and health of the employee", that is, they are interpreted statically (as a set...) and passively — without the participation of the employee in shaping the conditions of his work. This is probably why the working conditions are being investigated dose exposures of material factors that do not contribute to the identification of their primary connection with a working person — a connection that forms the result of the actual interaction of material factors with the animate at a certain time in a given workplace, the identification of which is available only to effective exposures of material factors — expositions of a higher level of quality, claiming to have the appropriate quality of rationing – comprehensive, universal, with an expanded scale of assessment of working conditions, and for the first time opens up the possibility of their identification, depending on the state and dynamics of the employee's health. In this study, scientists measured and evaluated the effective exposure of one of the most difficult to determine and evaluate the characteristics of the labor severity factor — the "Working posture". The experts gave an assessment in comparison with the traditionally defined basic exposures of the working position in the studied labor processes. The study aims to increase the accuracy of the hygienic assessment of the severity of work according to the indicator "Working posture" using a modern technique — pangoniometry. Materials and methods. In three groups of workers (2 car drivers, 10 doctors of clinical laboratory diagnostics and 30 electricians on duty), specialists applied three different methods of studying the working posture, two of which are widely represented in the normative and methodological and scientific literature, and the third was developed by the authors and was called pangoniometric. This technique consisted in drawing up diagrams of working poses, which are the material for measuring with the help of a protractor the limits of fluctuations in the degrees of motion of various parts of the locomotor system in joints. The researchers also measured the actual limits of fluctuations in angular degrees, determined that they exceeded the known optimal limits in areas of increased stress on the joint and the time of its operation in these areas. The authors have carried out statistical processing of the obtained material using the Student's t-test and the Pearson correlation coefficient. Results. It was found that the indicator of the effective effect of the forms of working poses obtained by the method of pangoniometry significantly, by 1–2 classes and degrees of harmfulness, clarifies the assessment of the severity of labor in comparison with the indicator of the dose exposure of working poses. Limitation. There were a small number of car drivers studied — two people. Conclusion. Pangoniometry is a method of physiological-hygienic and physiological-clinical comprehensive research and assessment of the impact of forms of working postures on health in the labor process. The method clarifies the hygienic assessment of the severity of work according to the indicator "Working posture" by identifying the primary relationship between the load on the joints and their working tension, materializing this important relationship in diagnostic and preventive terms in the indicator of the effective effect of the goniometric index of the working posture. In an indicator that has the property of being a guide to managing working conditions in the workplace by openly modeling elements of not only the material factor, but also the animate interacting with it, represented by the properties of the employee's body. Ethics. In preparing the article, the authors were guided by the Ethical principles of medical research set out in the Helsinki Declaration of the World Medical Association in the latest edition.

Efficacy of the CALM® Algorithm in Reducing Motion-Induced Artifacts in CBCT Imaging: A Fractal Dimension Analysis of Trabecular Bone.

The primary goal of this investigation was to ascertain the efficacy of the CALM® motion artifact reduction algorithm in diminishing motion-induced blurriness in Cone Beam Computed Tomography [CBCT] images. The assessment was conducted through Fractal Dimension [FD] analysis of the trabecular bone. A desiccated human mandible was subjected to Planmeca ProMax 3D® scanning under eight distinct protocols, marked by variations in motion presence [at 5, 10, and 15 degrees] and the deployment of CALM®. In every scan, five distinct regions of interest [ROIs] were designated for FD analysis, meticulously avoiding tooth roots or cortical bone. The FD was computed employing the box-counting method with Image-J 1.53 software. Our findings reveal that a 5-degree motion does not significantly disrupt FD analysis, while a 10-degree motion and beyond exhibit statistical differences and volatility among the sites and groups. A decreased FD value, signifying a less intricate or "rough" bone structure, correlated with amplified motion blurriness. The utilization of CALM® software seemed to counteract this effect in some instances, reconciling FD values to those akin to the control groups. Nonetheless, CALM®'s efficacy differed across sites and motion degrees. Interestingly, at one site, CALM® application in the absence of motion resulted in FD values considerably higher than all other groups. The study indicates that motion, particularly at 10 degrees or more, can considerably impact the FD analysis of trabecular bone in CBCT images. In some situations, the CALM® motion artifact reduction algorithm can alleviate this impact, though its effectiveness fluctuates depending on the site and degree of motion. This underscores the necessity of factoring in motion and the employment of artifact reduction algorithms during the interpretation of FD analysis outcomes in CBCT imaging. More research is necessary to refine the application of such algorithms and to comprehend their influence on different sites under varying motion degrees.

Submersible Position Prediction Model Based on HMM and Six Degrees of Freedom Motion

Submersible Position Prediction Model Based on HMM and Six Degrees of Freedom Motion

In Vivo Demonstration of a Real-Time Temporal SNR Acoustic Output Adjustment Method.

This work proposes a novel method of temporal signal-to-noise ratio (SNR)-guided adaptive acoustic output adjustment and demonstrates this approach during in vivo fetal imaging. Acoustic output adjustment is currently the responsibility of sonographers, but ultrasound safety studies show recommended as low as reasonably achievable (ALARA) practices are inconsistently followed. This study explores an automated ALARA method that adjusts the mechanical index (MI) output, targeting imaging conditions matching the temporal noise perception threshold. A 28-dB threshold SNR is used as the target SNR, following prior work showing relevant noise quantities are imperceptible once this image data quality level is reached. After implementing adaptive output adjustment on a clinical system, the average MI required to achieve 28-dB SNR in an 11-volunteer fetal abdomen imaging test ranged from 0.17 to 0.26. The higher MI levels were required when imaging at higher frequencies. During tests with 20-s MI adjustment imaging periods, the degree of motion impacted the adaptive performance. For stationary imaging views, target SNR levels were maintained in 90% of SNR evaluations. When scanning between targets the imaging conditions were more variable, but the target SNR was still maintained in 71% of the evaluations. Given the relatively low MI recommended when performing MI adjustment and the successful adjustment of MI in response to changing imaging conditions, these results encourage adoption of adaptive acoustic output approaches guided by temporal SNR.

Robotics In Gynecology- A Review

This review article focuses on the development of robotics-based operations in the medical field especially in gynecology. The goal of the surgical robot is to improve surgical skills and compensate for human limitations. The robot's performance in performing duties correctly and consistently has been the key to its success. Tubal anastomosis was the first gynecologic surgery performed with Robotic assistance in 2000 followed by first Robotic Hysterectomy in 2002. In 2003 Da Vinci surgical system was developed which was FDA approved for gynecological surgery in 2005. It has gained popularity fast and is already playing a big part in many of the places where it is available. It consists of a high-resolution three-dimensional (3D) vision system adjacent to the patient on a cart with robotic branches. It provides unique technical advancement, with tremor filtration, improved ergonomics and lower muscular load as compared to both laparoscopic and open surgeries. Autonomous camera and energy instrument control, wrist articulation with 7 degree freedom, telestration and dual- console capabilities, overcoming the limitations of conventional laparoscopy, such as counterintuitive hand movements, 2 dimensional visualization, limited degree of motion and tremor amplification. Compared to laparoscopy, robotic assistance has a lower conversion rate to open procedures. Endo wrist movement of an automated machine during myomectomy surgery can perform proper and better suturing than traditional laparoscopy. The automated program is a noticeable improvement over laparoscopic surgery and, if price issues are resolved, can gain popularity among gynecological surgeons around the globe. Not unique to robotic system, the integration of indigo cyanine green fluorescence with the Da Vinci robotic system allows identification of lesions, and assessment of perfusion of bowel and ureter during deep infiltrating endometriosis resection.

Biomechanical Comparison of Corticopedicular Spine Fixation versus Pedicle Screw Fixation in a Lumbar Degenerative Spondylolisthesis Finite Element Analysis Model

To compare the stability of a corticopedicular posterior fixation (CPPF) device with traditional pedicle screws for decompression and fusion in adult degenerative lumbar spondylolisthesis. Finite element analysis (FEA) was used in a validated model of grade 1 L4-L5 spondylolisthesis to compare segmental stability after laminectomy alone, laminectomy with pedicle screw fixation, or laminectomy with CPPF device fixation. A 500-N follower load was applied to the model and different functional movements were simulated by applying a 7.5-Nm force in different directions. Outcomes included degrees of motion, tensile forces experienced in the CPPF device, and stresses in surrounding cortical bone. At maximum loading, laminectomy alone demonstrated a 1° increase in flexion range of motion, from 6.35° to 7.39°. Laminectomy with pedicle screw fixation and CPPF device fixation both reduced spinal segmental motion to ≤1° at maximum loading in all ranges of motion, including flexion (0.94° and 1.09°), extension (-0.85° and -1.08°), lateral bending (-0.56° and -0.96°), and torsion (0.63° and 0.91°), respectively. There was no significant difference in segmental stability between pedicle screw fixation and CPPF device fixation during maximum loading, with a difference of ≤0.4° in any range of motion. Tensile forces in the CPPF device remained ≤51% the ultimate load to failure (487 N) and stress in surrounding cortical bone remained ≤84% the ultimate stress of cortical bone (125.4 MPa) during maximum loading. CPFF fixation demonstrated similar segmental stability to traditional pedicle screw fixation whereas tensile forces and stress in surrounding cortical bone remained below the load to failure.

Performance-based target reliability analysis of offshore wind turbine mooring lines subjected to the wind and wave

Reliability assessment is a crucial aspect of the design and operation of structures, particularly in balancing safety and cost considerations. This paper introduces a novel method for evaluating the performance-based target reliability of floating wind turbine platforms in offshore environments. The method focuses on the platform's motion modes and wave frequencies, which significantly influence the system's structural integrity and performance. An improved limit state function is proposed to enhance the accuracy of reliability calculations, specifically for steady-state conditions. The platform's six degrees of freedom motions are carefully analyzed to investigate their dependence on wave frequencies. By considering the time response of these motions and accounting for uncertainties in wave characteristics, wave impact directions, and wind effects, a comprehensive reliability analysis is conducted to assess the stability modes of the platform. This paper introduces the term 'Reliability Performance-Based' (RPB) analysis as a new concept to evaluate the system's reliability at a given performance level. Furthermore, an optimal target reliability index is defined to address the economic aspect of the design process. The proposed methodology's PEB analysis focuses on capturing uncertainties in wave characteristics and wind effects on floating wind turbine platforms. This includes a detailed examination of wave and wind-induced loads and their propagation through the system concerning its performance level. Statistical models were integrated to quantify these uncertainties, applying Monte Carlo simulations to assess their effects on the platform's reliability. This approach allows for a nuanced understanding of the interactions between environmental factors and structural responses, enhancing the precision of our reliability assessments. It enables the consideration of economic efficiency alongside safety, ensuring a balanced approach to the design and operation of the floating wind turbine platform. By providing a comprehensive reliability assessment framework, it aids in the optimization of design and decision-making processes for floating wind turbine platforms.

Comparison of dental force applied during endotracheal intubation with hyper-angulated and macintosh-type video laryngoscopy blades used by emergency medicine trainees: A randomized cross-over manikin study.

This study aimed to compare the effects of Macintosh-type and hyperangulated video laryngoscopy (VL) blades on dental force during endotracheal intubation (ETI) using Glidescope and McGrath VL devices. In this randomized, crossover, manikin study conducted at a university emergency medicine (EM) program, 65 EM trainees included interns and residents performed 520 intubations using four different VL blades (GlideScope VL with Macintosh-type Mac T3 and hyperangular Lo Pro T3 blades and McGrath VL Macintosh-type MAC 4 and hyperangular McGrath X3 blades) in normal and difficult airway scenarios. The primary outcome of this study was the dental pressure (Newton) exerted during ETI. The secondary outcomes included c-spine motion (degree), intubation success (%), duration (seconds), successful glottic view (%), and intubator comfort (7-point Likert). Significant differences were observed in dental force (H(3) = 11.7, P = 0.008), c-spine motion (H(3) = 8.34, P = 0.039), duration (H(3) = 16.56, P = 0.001), and comfort (H(3) = 174.96, P < 0.001) across blade types. Glidescope LoPro T3 provided a significant lower dental force (adjusted P = 0.01), less c-spine motion (adjusted P = 0.031), and shorter intubation duration (adj P < 0.01) than the McGrath Mac 4. First attempt success and intubator comfort were significantly better with all Glidescope blades (z score of 3.7 and 4.7) than with McGrath blades (z score of-4.1 and-4.4). The Glidescope LoPro T3 blade demonstrated advantages in dental force, c-spine motion, and intubation duration compared with McGrath Mac 4. Overall, the Glidescope blades provided superior comfort and higher first attempt success rates.

Robotic‑assisted minimally invasive pancreas surgery. Review

The use robotics in surgery is gaining momentum. This approach holds substantial promise in pancreas surgery. Minimally invasive techniques have been increasingly used in oncologic surgery and pancreatic surgery in particular. Minimally invasive pancreatectomy (MIP) has been performed with increasing frequency in all pancreatic pathologies, including pancreatic neuroendocrine tumors (PNETs), including pancreaticoduodenectomy (PD), distal pancreatectomy (DP), and pancreatic enucleation. Robotic‑assisted surgery using the DaVinci platform has accelerated the adoption of MIP. The proportion of robotic DP between 2015 and 2016 was nearly 4 times greater than between 2010 and 2012 (16% vs 4%), with a similar increase in proportion of robotic PD (7% vs 2%) over the same time frame. Advantages of robotic surgery over laparoscopy include three‑dimensional visualization, increased degrees of motion with endo‑articulation, stable camera platform, surgeon ergonomics, and single surgeon’s ability to control four instruments. Systematic adoption of MIP has been facilitated by the creation of multiple multicenter training programs in robotic DP and PD, aiming to standardize the oncologic safety and technical performance of these operations. Robotic surgery for pancreatic lesions and malignancies has become well accepted and is expanding to more and more center annually. The number of centers using robotics in pancreatic surgery is rapidly increasing. The most studied robotic pancreas surgeries are PD and DP. Most studies are in their early phases, but they report that robotic pancreas surgery is safe feasible. Robotic pancreas surgery offers several advantages over open and laparoscopic techniques. Data regarding costs of robotics versus conventional techniques is still lacking. Robotic pancreas surgery is still in its early stages. It holds promise to become the new surgical standard for pancreatic resections in the future, however, more research is still needed to establish its safety, cost effectiveness and efficacy in providing the best outcomes.

Freezing Hu ram semen: influence of different penetrating cryoprotectants and egg yolk level on the post-thaw quality of sperm.

The Hu sheep is a renowned breed known for its high reproductive rate. It is in estrus all year round, and its breeding population is gradually expanding. However, the current techniques for cryopreserving semen have limited effectiveness, which hinders the continuous development of this species. The purpose of this study is to explore the effects of different penetrating cryoprotectants (CPAs) and egg yolk (EY) concentrations on the cryopreservation of Hu ram semen to determine the most effective combination. In this study, the effects of glycerol (GLY), ethylene glycol (EG), dimethylacetamide, dimethyl sulfoxide, different proportions of GLY and EG, EY on sperm quality after thawing were investigated by detecting sperm total motility (TM), progressive motility (PM), straight-line velocity, curvilinear velocity, average path velocity, amplitude of lateral head displacement, wobble movement coefficient, average motion degree, functional integrity (plasma membrane integrity, acrosome integrity) and reactive oxygen species (ROS) level. When GLY and EG were added together, compared to other concentration groups, 6% GLY significantly (p<0.05) increased TM, PM, plasma membrane integrity, and acrosome integrity of thawed sperm. Additionally, it significantly (p<0.05) decreased the ROS level of sperm. In this study, the TM, PM, and membrane integrity of the 6% EG were significantly (p<0.05) higher than those of the control, 1% GLY+5% EG and 6% GLY+6% EG groups. Compared to other concentration groups, 20% EY significantly (p<0.05) improved the TM, PM, and plasma membrane integrity of thawed sperm. However, the integrity of the acrosome increased with the higher concentration of EY. In conclusion, the post-thawed Hu ram semen diluted with a diluent containing 6% GLY and 20% EY exhibited higher quality compared to the other groups.

Breaking the operator variability in Kibler’s scapular dyskinesis assessment

IntroductionAlterations of scapular kinematics are generically reported as scapular dyskinesis (SD), and are a nonspecific response to various shoulder pathologies. The most widely used classification is Kibler’s (K), which is, however, characterized by poor sensitivity. To overcome this limit, using a 3D motion analysis system, we identified a specific pattern for each type of SD according to Kibler.Materials and methodsWe analyzed 34 patients with a total of 68 shoulders who came to our observation for shoulder pain. All patients underwent clinical examination, video-recording and motion analysis with SHoW Motion 3D kinematic tracking system (SM). Three independent observers classified SD into K types I, II and III. Only patients with concordant classification among the 3 operators were studied to identify a characteristic graphic pattern by type of SD.ResultsTypical patterns emerged from the examination with SM. K. type 1 consists of decreased or reversed posterior tilt and increased protraction in flexion–extension (FE) in early degrees of motion. K. type 2 consists of increased protraction and marked reversal of lateral rotation in abduction–adduction (Ab–Ad) in early degrees of movement. K. type 3 has been subdivided into two subgroups: K. type 3-A, composed of patients with massive rotator cuff lesions, shows an increase in all scapular movements in both FE and Ab–Ad. K. type 3-B, composed of patients with scapular stiffness and/or impingement, presents a slight increase in posterior tilt and lateral rotation in the final grades of FE and Ab–Ad.ConclusionsThe SM system allows reproducible dynamic analyses with low intra- and intra- operator variability. In our study, we demonstrated its applicability in the classification of SD. It also provides an objective and quantitative assessment of motor pattern alteration that is essential in the follow-up of patients to evaluate the effectiveness of rehabilitation and/or surgical treatment.Level of Evidence 3According to "The Oxford 2011 Levels of Evidence".

Modeling and reduction of high frequency scatter noise at LIGO Livingston

The sensitivity of aLIGO detectors is adversely affected by the presence of noise caused by light scattering. Low frequency seismic disturbances can create higher frequency scattering noise adversely impacting the frequency band in which we detect gravitational waves. In this paper, we analyze instances of a type of scattered light noise we call ‘Fast Scatter’ that is produced by motion at frequencies greater than 1 Hz, to locate surfaces in the detector that may be responsible for the noise. We model the phase noise to better understand the relationship between increases in seismic noise near the site and the resulting Fast Scatter observed. We find that mechanical damping of the arm cavity baffles led to a significant reduction of this noise in recent data. For a similar degree of seismic motion in the 1– 3 Hz range, the rate of noise transients is reduced by a factor of ~50.

Effects of Different Diluents and Freezing Methods on Cryopreservation of Hu Ram Semen.

The purpose of this study was to investigate the effects of different diluents and freezing methods on the quality of thawed sperm after cryopreservation and find an inexpensive and practical method for freezing Hu ram semen for use in inseminations under farm conditions. Ejaculates were collected from five Hu rams. In experiment I, ejaculates were diluted with eight different freezing diluents (basic diluents A, B, C, D, E, F, G, and H). After dilution and cooling, the samples were loaded into 0.25 mL straws and frozen using the liquid nitrogen fumigation method. In experiment II, diluent C was used as the basic diluent and the semen was frozen using liquid nitrogen fumigation and two program-controlled cooling methods. For analysis, frozen samples were evaluated in terms of motility parameters (total motility (TM), progressive motility (PM)), biokinetic characteristics (straight-line velocity (VSL), average path velocity (VAP), curvilinear velocity (VCL), amplitude of lateral head displacement (ALH), wobble movement coefficient (WOB), average motion degree (MAD)), reactive oxygen species (ROS) level, and membrane and acrosome integrity. In experiment I, diluent C had higher TM, PM, and acrosome and membrane integrity and lower ROS compared to other extenders (p < 0.05) except diluent A. Diluent C exhibited higher (p < 0.05) VCL, VAP, ALH, WOB, and MAD compared to diluents B, D, E, and F. In experiment II, TM and all biokinetic characteristics did not show significant differences (p > 0.05) amongst the three freezing methods. Liquid nitrogen fumigation resulted in higher (p < 0.05) PM, membrane integrity, acrosome integrity, and lower ROS level compared to the program. In conclusion, the thawed semen diluted with diluent C had higher quality compared to other diluents. The liquid nitrogen fumigation demonstrated superior semen cryopreservation effects compared to the program-controlled cooling method using diluent C.

Anterior cervical hybrid constructs reduce superior adjacent segment burden compared to multilevel anterior cervical discectomy and fusion.

Traditional surgical treatment for symptomatic cervical degenerative disc disease is anterior cervical discectomy and fusion (ACDF), yet the increased risk of adjacent segment degeneration (ASD) requiring additional surgery exists and may result in limiting long-term surgical success when it occurs. Disc arthroplasty can preserve or restore physiologic range of motion (ROM), decreasing adjacent level stress and subsequent surgery. For patients with multilevel pathology requiring at least a 1-level fusion, interest is growing in anterior cervical hybrid (ACH) surgery as a partial motion-preserving procedure to decrease the adjacent level burden. This radiographic study compares postoperative superior adjacent segment motion between ACH and ACDF. Secondarily, total global motion, construct motion, inferior adjacent segment motion, and sagittal alignment parameters were compared. This is a single-center, multi-surgeon, retrospective cohort study of 2- and 3-level ACH and ACDF cases between 2013 and 2021. Degrees of motion were analyzed on flexion/extension views using Cobb angles to measure global (C2-C7) construct and adjacent segment lordosis. Neutral lateral X-rays were analyzed for alignment parameters, including global lordosis, cervical sagittal vertical axis (cSVA), and T1 slope (T1S). Differences were determined by independent t-test and Fisher's exact test. Of 100 patients, 38% were 2-level cases (47% ACH, 53% ACDF) and 62% were 3-level cases: (52% ACH, 48% ACDF). Postoperatively, superior adjacent segment motion increased with ACDF and decreased with ACH (-1.3°±5.3° ACH, 1.6°±4.6° ACDF, P=0.005). Postoperatively, the ACH group had greater ROM across the construct (16.3°±8.7° ACH, 4.7°±3.3° ACDF, P<0.001) and total global ROM (38.0°±12.8° ACH, 28.0°±11.1° ACDF, P<0.001). ACH resulted in a significant reduction of motion loss across the construct (-10.0°±11.7° ACH, -18.1°±10.8° ACDF, P<0.001). Postoperative alignment restoration was similar between both cohorts (-2.61°±8.36° ACH, 0.04°±12.24° ACDF, P=0.21). Compared to ACDF, hybrid constructs partially preserved motion across operative levels and had greater postoperative global ROM without increasing superior adjacent segment mobility or sacrificing alignment restoration. This supports the consideration of ACH in patients with multilevel degenerative cervical pathology requiring at least a 1-level fusion and suggests a propensity for long-term success by reducing the superior adjacent segment burden.

Flow-induced vibrations of a twistable two-tandem cylinder system across varied gap ratios

This paper presents a simulation study on the flow-induced vibrations (FIVs) of a two-tandem cylinder system with three degrees of freedom, encompassing in-flow, cross-flow, and torsional motions at a Reynolds number of 150. We specifically focus on investigating the impact of gap ratios (G*) between the cylinders, considering values of 0.5, 2, and 3. The ratio of torsional natural frequency to translational natural frequency was maintained at 12.5, while the mass ratio between the cylinder system and the fluid was set to 2. Our findings reveal a notable sensitivity of the FIV responses to the gap ratio between the cylinders. It was observed that the cylinder system's vibrations can undergo locking phenomena at both the translational and torsional natural frequencies, with maximal cross-flow amplitudes occurring within the torsional locked region. Particularly, at G* = 0.5, the maximal cross-flow amplitude reached approximately 21.4 times that of the cylinder system without torsional vibration, posing potential risks of fatigue failure in offshore equipment. Conversely, at G* = 2, an unusual ultra-low frequency was detected in the in-flow vibration. This phenomenon significantly magnified the FIV of the cylinder system, despite the absence of frequency locking. Furthermore, at G* = 3, we observed an expanded range of vibrations with ultra-low frequency compared to G* = 2. Our analysis identified the differential development speed of the shear layers around the upstream and downstream cylinders as a key factor contributing to varying vortex shedding frequencies. This discrepancy led to periodic changes in the vortex shedding mode of the cylinder system over time, thereby introducing low-frequency components into the flow-induced vibration. These insights deepen our understanding of the complex dynamics governing the FIV of tandem cylinder systems, which holds implications for the design and maintenance of offshore structures.

Unsteady aerodynamics of the floating offshore wind turbine due to the trailing vortex induction and airfoil dynamic stall

The trailing vortex induction effect and the airfoil dynamic stall are two main sources of the wind turbine unsteady aerodynamics. The unsteady aerodynamics of the floating offshore wind turbine (FOWT) is more complicated than its monopile counterpart due to the existence of the additional six degrees of freedom motion (6-DOF) of the floating platform. This paper focuses on the unsteady aerodynamics of the FOWT under surge condition results from the trailing vortex induction and airfoil dynamic stall, especially the resulting hysteresis effect, by adopting the free vortex wake (FVW) method coupled with the dynamic stall model. The reasons and manifestations of the hysteresis effect are discussed, and the effect of the operation conditions on the hysteresis effect of the FOWT are analyzed. Besides, other unsteady aerodynamic phenomena associated with the hysteresis effect are also included. Results show that, when the FOWT operates under surge condition, there exists a phase lag between the loads response and the variation of the rotor inflow velocity, which is a manifestation of the hysteresis effect. With the variation of the operation conditions of the FOWT, the phenomena such as dynamic stall, blade-wake interaction and the transition of the operation state may occur, and the manifestation of the hysteresis effect will be different.

Motion Accuracy of Pneumatic Stepper Motor-Driven Robotic System Developed for MRI-Guided High-Intensity Focused Ultrasound Treatment of Prostate Disease

The latest advancement in high-intensity focused ultrasound (HIFU) treatment technology integrates magnetic resonance imaging (MRI) guidance for precise treatment of prostate disease. As conventional electromagnetic motors are not applicable for utilization within MRI scanners, we have developed a prototype robotic system driven by pneumatic stepper motors to control the movement of the HIFU transducer within an intrarectal probe during MRI-guided HIFU treatment procedures. These pneumatic stepper motors were constructed entirely from MRI-compatible plastic materials. Assessment of the robotic system’s MRI compatibility was conducted utilizing a 3.0T MRI scanner, revealing no discernible MRI image distortion with a minor decrease in the signal-to-noise ratio (2.8%) during the motor operation. The robotic system enabled the transducer to move inside the probe with two degrees of freedom, allowing both linear and rotational motion. The positional accuracy of the transducer movement was assessed, yielding ±0.20 and ±0.22 mm accuracies in the forward and backward linear movements, respectively, and ±0.79° and ±0.74° accuracies in the clockwise and counterclockwise rotational motions, respectively. Emulation of authentic HIFU procedures involved creating a two-dimensional array of thermal lesions in a tissue-mimicking phantom, achieving positional accuracy within ±1 mm for the generated HIFU focal spots. The prototype robotic system incorporating pneumatic stepper motors fabricated entirely from MRI-compatible plastic materials has demonstrated the requisite positional accuracy necessary for effective HIFU treatment of prostate disease, indicating substantial promise for future clinical application.