Maximum Compression Research Articles

PO-02-185 OVAL DEVICE COMPRESSION AND SUBSEQUENT PERI DEVICE LEAKS (PDL) AFTER WATCHMAN FLX (WM FLX) DEVICE IMPLANTATION

Left atrial appendage closure (LAAC) with WM FLX is recommended for AF patients with high CHADS2VASC score who are intolerant to oral anticoagulants or at high risk of bleeding. LAAC can be challenging in some patients due to anatomy of the LAA. Even in patients with successful WM FLX deployment, some may develop PDL in the future. The factors resulting in development of PDL are not well understood. It is possible that LAA ostial remodeling is related to Device-LAA wall interactions and regional stress that is unevenly distributed. To study the relationship of Transesophageal Echo (TEE) guided measurements of LAA ostium post WM FLX device implantation with subsequent development of PDL. We identified all patients in past 2 years who underwent WM FLX device placement with reported new PDL on 6 week follow up TEE and compared it with a historical group who did not develop PDL. We evaluated the size of the LAA ostium measured by TEE before and immediately post WM FLX implant. We hypothesized that the patients that develop PDL may have unequal compression of the WM device in different axes (Oval instead of even circular compression) leading to remodeling that favors PDL development. Of 502 WM implants, PDL was reported in 57 patients at 6 week TEE with a incidence of 11.3%. We evaluated 133 patients who did not develop PDL as a control group. TEE measurements of LAA ostium were taken before and after WM FLX implantation in standard 0,45,90 and 135 degree views. The size of WM device used was not significantly different in PDL vs No-PDL group (Table 1). The difference between the axes with Minimum and Maximum compression- Delta Min-Max (Oval Index) was significantly higher in the PDL group compared to No-PDL group (3.03 vs 1.84 mm, p-value of 0.03). When adjusted for WM size, the difference in compression ratios (Min-Max axes) remained significantly higher in the PDL group compared to No PDL group (10.07% vs 7.01%, p-value of 0.004) Our analysis supports the hypothesis that an increased Oval Index and unequal compression post WM FLX implantation is associated with PDL development at 6 weeks. This has implications for WM FLX device implantation and suggests consideration of the Oval Index prior to device release. Further analysis is required to evaluate this and other factors involved in development of PDL post WM FLX.

Influence of alumina powder (Al2O3) on mechanical and tribological properties of injection molded polyoxymethylene composites

Composite materials combine two or more materials with mechanical and chemical properties that differ from one another. The matrix is one element, while the reinforcement is another. In this study, alumina powder (Al2O3) is used as filler while polyoxymethylene (POM) is used as the matrix. The injection moulding method is used to produce the composite specimens in this investigation. Prior to injection moulding, composite pellets are made using a twin-screw extruder. Compounding is done to produce a homogeneous mixture. The injection moulding method is the most efficient solution for mass-producing material with the slightest faults in samples. The advantage of injection moulding is that it only takes a few minutes to complete a cycle.The composite was put through mechanical, tribological, and morphological testing as part of this investigation to determine its strength. Tensile, flexural, and compression tests are examples of mechanical tests. A wear test is conducted with the help of a pin-on-disc setup. The specific wear rate of all the samples is calculated. The SEM is done to study the surface of the sample after the tensile test. From the tensile test, it is found that with the increase in the amount of tensile strength of composite decreases. The maximum flexural strength (180.92 N/mm2) is obtained for a sample with 1% of alumina powder. The maximum compression strength (91.88 N/mm2) is achieved for a sample with 4% of alumina powder. The SEM image shows the brittle failure of a composite.

Modeling and Optimization of the Blade Structural Parameters for a Turbomolecular Pump

The development of high-performance mass spectrometer and vacuum coating technology has placed higher demand on the vacuum level of turbomolecular pumps (TMPs), which are required to possess a greater compression ratio and faster pumping speed. There exists a relation of “as one falls, another rises” between the compression ratio and the pumping speed when traditional improvement methods are used. How to simultaneously increase the compression ratio and pumping speed is a very important question for the high-end turbomolecular pumps. In this study, on the basis of a parallel blade and thin gas aerodynamic model, several types of curved blade are presented to improve the pumping performance of TMPs. The comparison results show that the positive quadratic surface exhibited a better pumping performance than the other curved blades. After that, a hybrid optimization method based on a support vector machine (SVR) and particle swarm optimization (PSO) are proposed to obtain the structural parameters of the rotor blade for the highest pumping speed and maximum compression ratio. The optimization results show that, compared with the parallel blades, the compression single-stage blade row with quadratic surface structure was able to increase the maximum compression ratio by 10.35% and the maximum pumping speed factor by 4.61%. In addition, the intermediate single-stage blade row with quadratic surface structure increased the maximum compression ratio by 9.15% and the maximum pumping speed factor by 2.53%.

Experimental Study on High Strength Concrete with partial replacement of fine aggregate using polypropylene steel fiber

The present study is to investigates changes polypropylene used with various percentages such as 0%,0.5%,1%,1.5%,2%,2.5% in M25 grade of concrete. In this investigation, OPC 53 grade cement, fine and coarse aggregates were utilized. Further, the characteristics of each construction materials and polypropylene properties were determined under the laboratory tests. Afterwards, the specimens were constructed as per Indian standards then sent for seven days, fourteen days, and twenty-eight days curing, then the specimens were tested under the Tension, compression and flexural strength test. The attained maximum compression strength, tensile strength and flexural strength were 22.15N/mm2,3.81N/mm2,5.2 N/mm2, respectively. Finally, these highest strengths of polypropylene concrete, were achieved by 2.5% polypropylene used in concrete.

Microstructure and properties of FeCoNi1.5CrCup/Al high-entropy alloy strengthened aluminum matrix composites and finite element simulation

In this study, high-entropy alloy (HEA) particles were used as the reinforced phase to prepare a high strength-toughness FeCoNi1.5CrCup/Al aluminum matrix composite. On the condition of different HEA adding amount, the microstructure and macro/micro mechanical properties together with their relationship are characterized. The finite element simulation is conducted to calculate the macro/micro mechanical properties and acquire a well-fitting with the experimental data. The research shows that when the HEA adding amount is 15 wt%, the particulate size is moderate and evenly distributed in the matrix, the HEA/Al interface is tightly bonded and no impurity phase is formed. The corresponding yield, compressive strengths and maximum compression ratio are 202.6 MPa, 391.2 MPa and 59.7% separately, which reaches an optimized high level. The particulate, dislocation and interface strengthening mechanisms are regarded as the main positive factors. The created "HEA/Al composite micro/macro performance simulation" finite element model provides a new scheme and technical route for the design, preparation and mechanical properties research of new composite materials.

Buckling prevention of a single long NiTi tube compressive elastocaloric regenerator

Superelastic NiTi tubes have been used in elastocaloric coolers due to the good balance between mechanical stability and heat transfer efficiency, and the tube length increase is crucial to the driving force reduction and total cooling power increase of the coolers. The key challenge to adopt long superelastic NiTi tubes in compressive elastocaloric coolers is to prevent long tubes from buckling. In this article, a buckling prevention method of entraining a single long tubular material into a rigid and thick outer shell was proposed. The enhancement in the maximum compression load of a single long tubular material with an outer shell compared with the bare material was derived using the energy method. The proposed buckling prevention method was validated by compression experiments using a single long stainless-steel tube and outer shells of different materials and outer diameters. The buckling prevention method was successfully applied to a single long polycrystalline superelastic NiTi tube (outer diameter 5 mm, wall thickness 1 mm, and initial length 305 mm) in a layered-structured compressive elastocaloric regenerator. Several stress rise-drop-recover processes due to the friction and sliding of the tube were observed in the training, and the dependences of the stress-strain response of the tube on the applied stress and strain rate were also investigated. An elastocaloric cooler based on the single-long-tube compressive elastocaloric regenerator was constructed and it reached the highest temperature span, specific cooling power, and COP values of up to 5.7 K, 150 W∙kg−1, and 4.0, respectively. The results of the article are significant for developing large-power elastocaloric coolers.

The effect of cryogenic treatment on the microstructure and room-temperature mechanical properties of the (HEAp/Al) at different temperatures

At present, high entropy alloy particle reinforced aluminum matrix composites (HEAp/Al) have some shortcomings in performance. For example, it has high strength but low plasticity and processability. This paper mainly investigated how the different cryogenic temperature (−50 ℃, −100 ℃ and-196 ℃) affects the properties of (FeCoNi1.5CrCu)p/Al composites. When the cryogenic temperature drops, the maximum compression ratio (δ) and fracture energy of (FeCoNi1.5CrCu)p/Al composites enhances. The optimized − 196 ℃ sample exhibits the maximum δ of 25.21% and 5.31 × 107 J/m3 fracture energy that corresponds to high plasticity, toughness and Schmidt factor (SF). It also reaches the maximum nano-indentation and elastic modulus in the inter-diffusion layer. The enhancement of performance is attributed to its high compactness, fine HEA particles, nanometer-sized Cr precipitates around HEAP. After DCT, we can find that refined grains, massive high-angle boundary grains, induced texture are connected with the recrystallization and free energy. But those positive factors are counteracted by the significant decrease of dislocation density, which directly results in the decrease of compression strength.

THE CONTRIBUTION OF THE MASTICATORY MUSCLES TO PRODUCTION OF 3D OCCLUSAL LOADS ACROSS THE DENTAL ARCH

Occlusal loading and muscle forces during mastication aids in assessment of dental restorations and implants and jaw implant design; however, three-dimensional bite forces cannot be measured with conventional transducers, which obstruct the native occlusion. The aim of this study was to combine accurate jaw kinematics measurements, together with subject-specific computational modelling, to estimate subject-specific occlusal loading and muscle forces during mastication.Motion experiments were performed on one male participant (age: 39yrs, weight: 82kg) with healthy dentition. Two low-profile magnetic sensors were fixed to the participant's teeth and the two dental arches digitised using an intra-oral scanner. The participant performed ten continuous of chewing on a polyurethane rubber sample of known material properties, followed by maximal compression (clenching). This was repeated at the molars, premolars of both the left and right sides, and central incisors. Jaw motion was simultaneously recorded from the sensors, and finite element modelling used to estimate bite force. Specifically, simulations of chewing and biting were performed by driving the model using the measured kinematics, and bite force magnitude and direction quantified. Muscle forces were then evaluated using a rigid-body musculoskeletal model of the patient's jaw.The first molars generated the largest bite forces during chewing (left: 309 N, right: 311 N) and maximum-force biting (left: 496 N, right: 495 N). The incisors generated the smallest bite forces during chewing (75 N) and maximum-force biting (114 N). The anterior temporalis and superficial masseter muscles had the largest contribution to maximum bite force, followed by the posterior temporalis and medial pterygoid muscles.This study presents a new method for estimating dynamic occlusal loading and muscle forces during mastication. These techniques provide new knowledge of jaw biomechanics, including muscle and occlusal loading, which will be useful in surgical planning and jaw implant design.

Lossy Image Compression in a Preclinical Multimodal Imaging Study.

The growing use of multimodal high-resolution volumetric data in pre-clinical studies leads to challenges related to the management and handling of the large amount of thesedatasets. Contrarily to the clinical context, currently there are no standard guidelines to regulate the use of image compression in pre-clinical contexts as a potential alleviationof this problem. In this work, the authors study the application of lossy image coding to compress high-resolution volumetric biomedical data. The impact of compression on the metricsand interpretation of volumetric data was quantified for a correlated multimodal imaging study to characterize murine tumor vasculature, using volumetric high-resolution episcopic microscopy (HREM), micro-computed tomography (µCT), and micro-magnetic resonance imaging (µMRI). The effects of compression were assessed by measuring task-specific performances of several biomedical experts who interpreted and labeled multiple data volumes compressed at different degrees. Wedefined trade-offs between data volume reduction and preservation of visual information, which ensured the preservation of relevant vasculature morphology at maximum compression efficiency across scales. Using the Jaccard Index (JI) and the average Hausdorff Distance (HD) after vasculature segmentation, we coulddemonstrate that, in this study, compression that yields toa 256-fold reduction of the data size allowed to keep the error induced by compression below the inter-observer variability, with minimal impact on the assessment of the tumor vasculature across scales.

Quantitative evaluation of the spinal cord compression in patients with cervical spondylotic myelopathy using synthetic MRI.

Objectives: This work aimed to investigate the feasibility and diagnostic value of synthetic MRI, including T1, T2 and PD values in determining the severity of cervical spondylotic myelopathy (CSM). Methods: All subjects (51 CSM patients and 9 healthy controls) underwent synthetic MRI scan on a 3.0TGEMR scanner. The cervical canal stenosis degree of subjects was graded 0-III based on the method of a MRI grading system. Regions of interest (ROIs) were manually drawn at the maximal compression level (MCL) by covering the whole spinal cord to generate T1MCL, T2MCL, and PDMCL values in grade I-III groups. Besides, anteroposterior (AP) and transverse (Trans) diameters of the spinal cord at MCL were measured in grade II and grade III groups, and relative values were calculated as follows: rAP = APMCL/APnormal, rTrans = TransMCL/Transnormal. rMIN = rAP/rTrans. Results: T1MCL value showed a decreasing trend with severity of grades (from grade 0 to grade II, p < 0.05), while it increased dramatically at grade III. T2MCL value showed no significant difference among grade groups (from grade 0 to grade II), while it increased dramatically at grade III compared to grade II (p < 0.05). PDMCL value showed no statistical difference among all grade groups. rMIN of grade III was significantly lower than that of grade II (p < 0.05). T2MCL value was negatively correlated with rMIN, whereas positively correlated with rTrans. Conclusion: Synthetic MRI can provide not only multiple contrast images but also quantitative mapping, which is showed promisingly to be a reliable and efficient method in the quantitative diagnosis of CSM.

Numerical Evaluation of Transverse Steel Connector Strengthening Effect on the Behavior of Rubble Stone Masonry Walls under Compression Using a Particle Model

The structural rehabilitation of historic/traditional rubble masonry wall constructions requires consolidation and retrofitting solutions to be employed in order to withstand dynamic loads, high vertical loads, and differential settlements. One of these strengthening techniques is based on the use of steel bar connectors perpendicular to the wall, considered individually or integrated into more complex strengthening techniques. The aim of this study is to evaluate numerically the strengthening effect of transverse steel connectors on rubble masonry walls. With this purpose, a 2D particle-reinforced model (2D-PMR) was devised and applied to model uniaxial compression tests. The results presented show that predictions calculated using the proposed 2D-PMR model are very close to known experimental results, particularly in the corresponding failure modes, the increase of the maximum uniaxial compression value, and ductility. Parametric studies are also conducted by varying the diameter of the steel bars and the level of strengthening to assess the influence of the bar-bond effect and lateral plates. The presented parametric numerical studies show that (i) a two-level strengthening solution guarantees a similar response to the three-level strengthening solution adopted in the experiments; (ii) it is not relevant to apply a grout injection during the application process of the steel connectors if lateral plates are adopted; and (iii) the 2D-PMR model can be used in the definition of the steel bar diameter and properties; as shown, a smaller (8 mm) bar diameter predicts a similar strengthening effect to the (12 mm) bar size adopted in the experiments. Given the performance of the proposed 2D-PMR model, further work is underway that will allow the 2D-PMR model to numerically assess other reinforcement techniques, namely, reinforced micro-concrete layers and textile reinforced mortar.

The Effect of Different Fibers on Granite Residual Soil Reinforced with Alkaline Solution

This study explores the reinforcement effect of different fibers in an alkaline solution on the mechanical properties of granite residual soil using the single variable method. The macroscopic mechanical properties of the reinforced samples were studied using the unconfined lateral compressive strength test and the drop-weight load test, while the microscopic properties were characterized using techniques such as SME and XRD. The results indicated that the greatest reinforcing effect was attained when the ratio of SiO2/Na2O in the alkaline solution was 0.5 mol with the compressive strength of 4402.85 kPa. At the time, the reinforcing effect of glass fiber in an alkaline solution on granite residual soil was superior to that of basalt fiber. The inclusion of glass fibers and an alkaline solution of 0.5 mol SiO2/Na2O into the granite residual soil exhibited the best capacity for reinforcing, with the maximum impact load and compression reaching 120 kN and 12.1 mm, respectively. The findings of SME analysis revealed that GRS included a significant amount of kaolinite, which, when decomposed in an alkaline solution, generated a gel substance that bound the fibers and soil together and filled the pores between them, thereby enhancing the sample’s compactness. XRD results demonstrated the formation of gel and a small amount of geopolymer in the soil under the alkaline solution of 0.5 mol SiO2/Na2O, which tighten the binding between soil particles and fibers and increase the overall strength.

Review on performance and emission of spark ignition engine using exhaust gas recirculation

ABSTRACT Modernizing electronic control and developing new exhaust gas recirculation (EGR) valves have made it possible to improve EGR accuracy and shorten transient response times. With this paper, we have outlined the findings of research on the effects of various EGR ratios on engine emissions, knock suppression, and charge combustion. Results from experiments conducted by many researchers are summed up as 15% − 18% EGR is found to successfully reduce NOx emissions without impacting engine performance. Because exhaust fumes dilute the fuel/air mixture, this can lead to inefficient combustion, which can lower brake thermal efficiency. According to the findings, selecting the right EGR ratio and spark timing is essential for maximizing engine performance. examined how cold EGR affected knock intensity. It was found that the maximum compression temperature decreased in range of 30–40 kelvin and the cylinder pressure decreased up to 0.4 bar as the EGR increased from 7 to 13%. This demonstrated that the knock was effectively repressed. Because of a buildup of carbon deposits, the EGR valve frequently sticks. In addition to higher fuel consumption or poorer performance, clogged EGRs frequently result in black smoke coming from the exhaust.

Shafranov shift correction to the Furth–Yoshikawa scaling of tokamak adiabatic compression

In 1970, Furth and Yoshikawa (1970 Phys. Fluids 13 2593–6) introduced the scalings of adiabatic plasma compression. Basically, if the shape of the external plasma boundary and the aspect ratio are preserved during the compression, then the density, kinetic pressure, beta and current scale respectively as , , , , , where C is the linear compression ratio, that is, the ratio between initial and final major radii. In this work, we show analytically, by expanding the Grad–Shafranov equation in terms of C, that the deviation to the Furth–Yoshikawa scaling is related to the Shafranov shift that arises when beta increases at large compression ratios. There is an obvious effect of the Shafranov shift because the axis is moved to a region with larger volume element, and an indirect effect, associated to the relation between flux and radius. The latter effect adds to the first, and is of the same order of magnitude. The result is that the pressure increases less than the C 5 scaling, which can have a significant impact on the fusion power achieved at maximum compression. The analytical results are backed up by equilibrium simulations carried out with the CHEASE code. Equilibria are obtained for different values of C, with conservation of the total fluxes, q profile, and entropy of the plasma. The agreement of the theory and simulations is very good when the boundary of the plasma is circular and the aspect ratio small. When the aspect ratio is close to 1, and/or the boundary not circular, the analytical result gives the gist of the reduction of compression. Finally, a pressure anisotropy approximately equal to the increase in normalized Shafranov shift is predicted.

Reconstructive Allograft Preparation for Long Bone Intercalary Segments After Tumor Resections: Toronto Sarcoma Protocol.

Reconstructive Allograft Preparation for Long Bone Intercalary Segments After Tumor Resections: Toronto Sarcoma Protocol.

A Novel Low-Power Compression Scheme for Systolic Array-Based Deep Learning Accelerators

The proliferation of deep learning algorithms has catalyzed their utilization to solve a multitude of real-world problems. Algorithms such as deep neural networks (DNNs) are compute- and power-intensive, thereby accentuating the development of hardware platforms like DNN inference accelerators. However, inference execution of large DNNs in resource-constrained environments induces energy bottlenecks in these accelerators. Since large DNNs consist of hundreds of millions of trained parameters, accessing them from the accelerator memory incurs substantial energy. To address this challenge, we propose HardCompress, which, to the best of our knowledge, is the first low-power solution that uses traditional compression strategies pertaining to commercial DNN accelerators in resource-constrained IoT edge devices. The three-step approach involves hardware-based post-quantization trimming of weights, followed by their dictionary-based compression and subsequent decompression by a low-power hardware engine during inference in the accelerator. We evaluate the proposed solution on lightweight networks trained on the MNIST dataset, the compact model trained on the CIFAR-10 dataset, and large DNNs trained on the ImageNet dataset. Performance of HardCompress at different quantization levels has been analyzed. Furthermore, to quantify the effectiveness of the proposed solution, an energy framework that contrasts the DRAM energies of the original and HardCompressed models has been developed. Finally, a fault injection framework which compares the fault resilience of the original model with its HardCompressed counterpart is also proposed. Our results exhibit that HardCompress, without any performance degradation in large DNNs, furnishes a maximum compression of 99.27%, equivalent to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$137\times $ </tex-math></inline-formula> reduction in memory footprint and 0.07 J for 8-bit quantization in the systolic array-based DNN accelerator. Furthermore, our proposed low-power decompression engine incurs an area overhead of only 0.02%; thus, enabling HardCompress’ utilization in resource-constrained environments.

MP03-18 A NOVEL METHOD FOR DERIVING BLADDER PROVOKED COMPLIANCE FROM ABDOMINAL COMPRESSIONS DURING ULTRASOUND URODYNAMICS

You have accessJournal of UrologyCME1 Apr 2023MP03-18 A NOVEL METHOD FOR DERIVING BLADDER PROVOKED COMPLIANCE FROM ABDOMINAL COMPRESSIONS DURING ULTRASOUND URODYNAMICS Julia Smolen, Chris Keshishian, Adam J. Vossenberg, Sarah Kodama, Ria Khandpur, Jared Dunlap, Abraham Alattar, Isabelle Pummill, Gabrielle Grob, Mina P. Ghatas, Linda S. Burkett, Lauren N. Siff, Adam P. Klausner, and John E. Speich Julia SmolenJulia Smolen More articles by this author , Chris KeshishianChris Keshishian More articles by this author , Adam J. VossenbergAdam J. Vossenberg More articles by this author , Sarah KodamaSarah Kodama More articles by this author , Ria KhandpurRia Khandpur More articles by this author , Jared DunlapJared Dunlap More articles by this author , Abraham AlattarAbraham Alattar More articles by this author , Isabelle PummillIsabelle Pummill More articles by this author , Gabrielle GrobGabrielle Grob More articles by this author , Mina P. GhatasMina P. Ghatas More articles by this author , Linda S. BurkettLinda S. Burkett More articles by this author , Lauren N. SiffLauren N. Siff More articles by this author , Adam P. KlausnerAdam P. Klausner More articles by this author , and John E. SpeichJohn E. Speich More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003214.18AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Bladder wall response to stretch is measured through compliance, and during urodynamics (UDS), “filling compliance” is calculated as Δvolume/Δpressure. The objective of this study was to use ultrasound (US) during UDS to derive a novel provoked compliance metric in response to abdominal bladder compressions, instead of filling, and correlate this with participant characteristics and filling compliance. METHODS: Individuals indicated for UDS were enrolled in a prospective IRB-approved study. Participants’ bladders were filled to ∼50% capacity during UDS and filling was paused. The US probe was used to perform 5 sec compressions of the bladder 5 times to ∼50% of its anterior-posterior diameter, with 5 sec between compressions. One transverse abdominal US image captured before compression and one at the maximum compression pressure were analyzed. Tracing of each transverse bladder wall image and the ImageJ circularity function (Figure 1AB) were used to quantify bladder circularity. Compression induced Δcircularity/Δpressure was used to calculate provoked compliance. Filling compliance was also calculated, and age and BMI data were collected. RESULTS: Data from 31 women were analyzed in groups ≤60 and >60 years of age. A wider range of provoked compliance values was found in women >60 (Figure 1C, above horizontal line). Provoked compliance between 0.006 and 0.022 cm-H2O-1 was demonstrated in 12/13 (92%) of women <60 years of age, but only 5/18 (28%) of women >60 years (Figure 1C), indicating a significant association of age with provoked compliance (Fisher’s exact, p<0.05). There was no identified association between filling compliance or BMI and provoked compliance. CONCLUSIONS: Provoked compliance in response to bladder compression was quantified using a novel method, and women >60 demonstrated altered provoked compliance. Future studies connecting provoked compliance and specific types of bladder dysfunction are needed to demonstrate key relationships. Source of Funding: NIH R01DK101719, NSF REU 1852116, VCU School of Medicine Summer Research Fellowship © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e30 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Julia Smolen More articles by this author Chris Keshishian More articles by this author Adam J. Vossenberg More articles by this author Sarah Kodama More articles by this author Ria Khandpur More articles by this author Jared Dunlap More articles by this author Abraham Alattar More articles by this author Isabelle Pummill More articles by this author Gabrielle Grob More articles by this author Mina P. Ghatas More articles by this author Linda S. Burkett More articles by this author Lauren N. Siff More articles by this author Adam P. Klausner More articles by this author John E. Speich More articles by this author Expand All Advertisement PDF downloadLoading ...

Self-focusing effect of focused array beams propagating from the space orbit through the atmosphere to the ground

For the incoherent beam combination, the self-focusing effect of focused array beams propagating from the space orbit through the atmosphere to the ground is studied. It is shown that the self-focusing effect in the atmosphere becomes stronger as the fill factor increases. When the circumcircle diameter and the fill factor of array beams are fixed, the self-focusing effect in the atmosphere becomes stronger as the element number N decreases. However, for the maximal beam compression case, the self-focusing effect in the atmosphere can assist delivering much more powerful array beams from the space orbit to the ground as N increases, and an array beam has the advantage to deliver powerful laser beam compared with a single laser beam. In particular, an effective design rule for maximal compression without filamentation of transported array beams from orbit to the ground is derived.

Prognostic MRI parameters in acute traumatic cervical spinal cord injury

PurposeThe aim of this study is to estimate the prognostic value of some features documented on preoperative MRI study in patients with acute cervical spinal cord injury.MethodsThe study was conducted in patients operated for cervical spinal cord injury (cSCI) from April 2014 to October 2020.The quantitative analysis on preoperative MRI scans included: length of the spinal cord intramedullary lesion (IMLL the canal diameter at the level of maximal spinal cord compression (MSCC) and the presence of intramedullary hemorrhage. The canal diameter at the MSCC was measured on the middle sagittal FSE-T2W images at the maximum level of injury.The America Spinal Injury Association (ASIA) motor score was used for neurological assessment at hospital admission. At 12-month follow-up all patients were examined with the SCIM questionnaire.ResultsAt linear regression analysis, the length of the spinal cord lesion [β coefficient −10.35, 95% confidence interval (CI)−13.71 to−6.99; p < 0.001], the diameter of the canal at the level of the MSCC (β coefficient 6.99, 95% CI 0.65 to 13.33; p = 0.032), and the intramedullary hemorrhage (β coefficient − 20.76, 95% CI − 38.70 to − 2.82; p = 0.025), were significantly associated with the score at the SCIM questionnaire at one year follow-up: shorter spinal cord lesion, greater diameter of the canal at the level of the MSCC, and absence of intramedullary hemorrhage were predictors of better outcome.ConclusionAccording to the findings of our study, the spinal length lesion, canal diameter at the level of spinal cord compression and intramedullary hematoma documented by the preoperative MRI study were associated with the prognosis of patients with cSCI.

Exploring the modification factors of exercise therapy on biomechanical load in patients with knee osteoarthritis: a systematic review and meta-analysis.

The objective of this systematic review and meta-analysisis to clarify the effect of exercise therapy on the first peak knee adduction moment (KAM), as well as other biomechanical loads in patients with knee osteoarthritis (OA), and identify physical characteristics that influence differences in biomechanical load after exercise therapy. The data sources are PubMed, PEDro, and CINAHL, from study inception to May 2021. The eligibility criteria include studies evaluating the first peak (KAM), peak knee flexion moment (KFM), maximal knee joint compression force (KCF), or co-contraction during walking before and after exercise therapy in patients with knee OA. The risk of bias was independently assessed by two reviewers usingPEDro and NIH scales. Among 11 RCTs and nine non-RCTs, 1119 patients with knee OA were included (average age: 63.7 years). As the results of meta-analysis, exercise therapy tended to increase the first peak KAM (SMD 0.11; 95% CI: -0.03-0.24), peak KFM (SMD 0.13; 95% CI: -0.03-0.29), and maximal KCF (SMD 0.09; 95% CI -0.05-0.22). An increased first peak KAM was significantly associated with a larger improvement in knee muscle strength and WOMAC pain. However,the quality of evidence regarding the biomechanical loads was low-to-moderate according to the GRADE approach.The improvement in pain and knee muscle strength may mediate the increase in first peak KAM, suggesting difficulty in balancing symptom relief and biomechanical load reduction. Therefore, exercise therapy may satisfy both aspects simultaneously when combined with biomechanical interventions, such as a valgus knee brace or insoles. Registration: PROSPERO (CRD42021230966).