Extensionality Research Articles

Test–Retest Reliability of Concentric and Eccentric Muscle Strength in Knee Flexion–Extension Controlled by Functional Electromechanical Dynamometry in Female Soccer

In the field of sports performance, sports medicine, and physical rehabilitation, there is a great interest in the development of protocols and reliable techniques and instruments for the evaluation of strength produced by athletes. In the last ten years, women’s football has increased its popularity and participation in numerous countries, which has contributed to players developing more professionally and requiring more specific muscle strength training to improve their performance. The aim of this study was to analyze the absolute and relative test–retest reliabilities of peak muscle strength in knee flexion (FLE) and extension (EXT) controlled using a functional electromechanical dynamometer (FEMD) in a group of seventeen professional female soccer players (age = 18.64 ± 0.62 years; weight = 54.72 ± 7.03 kg; height = 1.58 ± 0.04 m; BMI = 21.62 ± 2.70 kg/m2). Peak muscle strength was measured with knee flexion (FLE) and extension (EXT) movements at a speed of 0.4 m·s−1 unilaterally in a concentric phase (CON) and an eccentric phase (ECC). No significant mean differences were found in the test–retest analysis (p > 0.05; effect size < 0.14), and high reliability was reported for peak muscle strength assessments in both the CON (ICC) = 0.90–0.95) and the ECC (ICC = 0.85–0.97). Furthermore, stable repeatability was presented for extension in the CON (CV = 7.39–9.91%) and ECC (CV = 8.65–13.64). The main findings of this study show that peak muscle strength in knee flexion and extension in CON and ECC is a measure with acceptable absolute reliability and extremely high relative reliability using the FEMD in professional female soccer players.

Copper substituted manganese Prussian blue analogue composite nanostructures for efficient aqueous zinc-ion batteries

Aqueous zinc (Zn)-ion batteries (AZIBs) are considered a promising green energy storage alternative due to their large capacity, low cost, and exceptional safety. Prussian blue analogues (PBAs) with a robust three-dimensional structure and extensive ion channels are highly favorable for Zn2+ insertion/extraction, surpassing manganese (Mn) and vanadium oxides. Herein, copper (Cu) substituted Mn PBA (CuMn PBA) composite nanostructures are synthesized via a simple water-based co-precipitation technique using different concentrations of Cu and Mn sources. The partial substitution of Cu and the formation of Mn vacancies prevent Jahn-Teller distortions of MnN6 octahedra, extending the lifespan. The CuMn PBA-2 electrode exhibits a high discharge capacity of 175.14 mA h g−1 at 0.5 A g−1, superior rate capability of 89.08 mA h g−1 at 2.4 A g−1, and robust cycling stability, maintaining 73.15 mA h g−1 over 2000 cycles at 3 A g−1. Furthermore, the distinct structure provides numerous active sites and reduces volume volatility during cycling. The presence of Cu enhances electrode conductivity, thereby promoting a higher rate of Zn-ion diffusion between electrodes. The reversible intercalation and deintercalation of Zn2+ ions in the CuMn PBA-2 cathode are substantiated by ex-situ analysis methods. This work presents a novel approach for producing high-performance and stable PBA cathode materials for AZIBs.

Cross-education effects of balance training in individuals with chronic ankle instability

BackgroundIndividuals with chronic ankle instability (CAI) often experience deficits in balance, hip strength, and lumbopelvic stability. Unilateral balance training can lead to improved balance in the contralateral limb, but it is unknown if similar cross-education effects occur for hip strength and lumbopelvic stability. Our purpose was to determine if unilateral balance training improved balance, hip strength, and lumbopelvic stability of the contralateral limbs in individuals with CAI. MethodsUsing a randomized-controlled trial, 30 individuals with CAI were separated into control (CON) and balance (BAL). Uninvolved limbs underwent testing at baseline and post-intervention. We tested balance with the star excursion balance test in anterior (SEBT-ANT), posterolateral (SEBT-PL), and posteromedial (SEBT-PM) directions. We tested hip strength with a handheld dynamometer in extension (EXT), abduction (ABD), and external rotation (ER). We tested lumbopelvic stability with a unilateral hip bridge. After baseline, BAL completed an 8-week balance training program on the involved limb. CON did not participate in the intervention. Two-way repeated measures ANOVAs analyzed effects of group and time on each outcome. Cohen's d effect sizes analyzed each group's changes from baseline to post-intervention. ResultsEleven participants discontinued the study (5 CON, 6 BAL) before completion. There were significant group-by-time interactions for SEBT-PL (P = 0.03) and hip bridge (P = 0.03). BAL had moderate to large effect sizes for SEBT-PM (d = 0.69 [-0.06,1.41]), SEBT-PL (d = 0.87 [0.10,1.60]), EXT (d = 0.73 [-0.02,1.45]), ABD (d = 0.79 [0.03,1.51]), and hip bridge (d = 0.83 [0.07,1.55]). ConclusionA balance training program for limbs with CAI led to contralateral improvements in balance, hip strength, and lumbopelvic stability.

Recyclable Fe3O4@UiO-66-PDA core–shell nanomaterials for extensive metal ion adsorption: Batch experiments and theoretical analysis

With the ever-increasing challenge of heavy metal pollution, the imperative for developing highly efficient adsorbents has become apparent to remove metal ions from wastewater completely. In this study, we introduce a novel magnetic core–shell adsorbent, Fe3O4@UiO-66-PDA. It features a polydopamine (PDA) modified zirconium-based metal–organic framework (UiO-66) synthesized through a simple solvothermal method. The adsorbent boasts a unique core–shell architecture with a high specific surface area, abundant micropores, and remarkable thermal stability. The adsorption capabilities of six metal ions (Fe3+, Mn2+, Pb2+, Cu2+, Hg2+, and Cd2+) were systematically investigated, guided by the theory of hard and soft acids and bases. Among these, three representative metal ions (Fe3+, Pb2+, and Hg2+) were scrutinized in detail. The activated Fe3O4@UiO-66-PDA exhibited exceptional adsorption capacities for these metal ions, achieving impressive values of 97.99 mg/g, 121.42 mg/g, and 130.72 mg/g, respectively, at pH 5.0. Moreover, the adsorbent demonstrated efficient recovery from aqueous solution using an external magnet, maintaining robust adsorption efficiency (>80%) and stability even after six cycles. To delve deeper into the optimized adsorption of Hg2+, density functional theory (DFT) analysis was employed, revealing an adsorption energy of -2.61 eV for Hg2+. This notable adsorption capacity was primarily attributed to electron interactions and coordination effects. This study offers valuable insights into metal ion adsorption facilitated, by magnetic metal–organic framework (MOF) materials.

Decalf: A Directed, Effectful Cost-Aware Logical Framework

We present decalf , a d irected, e ffectful c ost- a ware l ogical f ramework for studying quantitative aspects of functional programs with effects. Like calf , the language is based on a formal phase distinction between the extension and the intension of a program, its pure behavior as distinct from its cost measured by an effectful step-counting primitive. The type theory ensures that the behavior is unaffected by the cost accounting. Unlike calf , the present language takes account of effects , such as probabilistic choice and mutable state. This extension requires a reformulation of calf ’s approach to cost accounting: rather than rely on a ”separable” notion of cost, here a cost bound is simply another program . To make this formal, we equip every type with an intrinsic preorder, relaxing the precise cost accounting intrinsic to a program to a looser but nevertheless informative estimate. For example, the cost bound of a probabilistic program is itself a probabilistic program that specifies the distribution of costs. This approach serves as a streamlined alternative to the standard method of isolating a cost recurrence and readily extends to higher-order, effectful programs. The development proceeds by first introducing the decalf type system, which is based on an intrinsic ordering among terms that restricts in the extensional phase to extensional equality, but in the intensional phase reflects an approximation of the cost of a program of interest. This formulation is then applied to a number of illustrative examples, including pure and effectful sorting algorithms, simple probabilistic programs, and higher-order functions. Finally, we justify decalf via a model in the topos of augmented simplicial sets.

Stabilization of lithium metal in concentrated electrolytes: effects of electrode potential and solid electrolyte interphase formation.

Lithium (Li) metal negative electrodes have attracted wide attention for high-energy-density batteries. However, their low coulombic efficiency (CE) due to parasitic electrolyte reduction has been an alarming concern. Concentrated electrolytes are one of the promising concepts that can stabilize the Li metal/electrolyte interface, thus increasing the CE; however, its mechanism has remained controversial. In this work, we used a combination of LiN(SO2F)2 (LiFSI) and weakly solvating 1,2-diethoxyethane (DEE) as a model electrolyte to study how its liquid structure changes upon increasing salt concentration and how it is linked to the Li plating/stripping CE. Based on previous works, we focused on the Li electrode potential (ELi with reference to the redox potential of ferrocene) and solid-electrolyte-interphase (SEI) formation. Although ELi shows a different trend with DEE compared to conventional 1,2-dimethoxyethane (DME), which is accounted for by different ion-pair states of Li+ and FSI-, the ELi-CE plots overlap for both electrolytes, suggesting that ELi is one of the dominant factors of the CE. On the other hand, the extensive ion pairing results in the upward shift of the FSI- reduction potential, as demonstrated both experimentally and theoretically, which promotes the FSI--derived inorganic SEI. Both ELi and SEI contribute to increasing the Li plating/stripping CE.

Untargeted Analysis of Short-Chain Peptides in Urine Samples Short Peptides Analysis.

Short-chain peptides have attracted increasing attention in different research fields, including biomarker discovery, but also a well-known analytical challenge in complex matrices due to their low abundance compared to other molecules, which can cause extensive ion suppression during mass spectrometric acquisition. Moreover, there is a lack of analytical workflows for their comprehensive characterization since ordinary peptidomics strategies cannot identify them. In this context, an enrichment strategy was introduced and developed to isolate and clean up short-chain peptides by graphitized carbon black solid phase extraction. For better coverage of peptide polarity, urine samples were analyzed by ultrahigh performance liquid chromatography by reversed-phase and hydrophilic interaction liquid chromatography. High-resolution mass spectrometry allowed the detection of the eluting peptides by data-dependent mode using a suspect screening strategy with an inclusion list; peptides were identified by a semiautomated workflow implemented on Compound Discoverer. The complementarity of the orthogonal separation strategy was confirmed by peptide identification, resulting in 101 peptides identified from the RP runs, and 111 peptides from the HILIC runs, with 60 common identifications.

Examining the Link between Isokinetic Strength Metrics and Ball Speed in Women’s Soccer

The shot performance of female soccer players is one of the most critical factors in winning a soccer match. It is essential to thoroughly clarify the kinetic factors that can improve shot performance. This study explores the connections between ball velocity post-shooting and isokinetic knee extension (EXT) and flexion (FLX) strength performances among female soccer players. Thirteen voluntary players from professional leagues took part in the research study. The study analyzed the average and peak concentric (Con) and eccentric (Ecc) torques, isometric (Iso) strength performances at angular velocities of 60°/s, 180°/s and 300°/s, the time required to reach peak torque, and ball velocities during shooting. The relationships among these variables were investigated separately for the dominant (D) and non-dominant (ND) legs. The analysis unveiled significant correlations between ball velocities and D-EXT (Absolute) peak torque at an angular velocity of 60°/s (r = 0.597; p < 0.05), D-%IPS (r = −0.580; p < 0.05), and ND-FLX (Absolute) average torque (r = 0.559; p < 0.05). Moreover, notable associations were observed between ball velocities and ND-EXT (Absolute) (r = 0.581; p < 0.05), as well as ND-FLX (Absolute) (r = 0.602; p < 0.05) average torques at an angular velocity of 180°/s. Additionally, significant relationships were found between ball velocities and peak (r = 0.664; p = 0.013) and average (r = 0.660; p = 0.014) torques generated during ND-EXT (Absolute) at an angular velocity of 300°/s. However, the connections between the time to reach peak torque, eccentric and isometric forces, and ball velocities were not statistically significant (p > 0.05). The results of the study indicate that enhancing concentric isokinetic strength development at 60°/s, 180°/s, and 300°/s angular velocities, along with balanced strengthening of the ND extremity, holds paramount importance in elevating shot performance among female soccer players, particularly in the context of rapid shot strategies.

Acid-resistance of one-part geopolymers: Sodium aluminate and carbonate as alternative activators to conventional sodium metasilicate and hydroxide

In this study, the durability of one-part geopolymers (OPGs) made from high calcium fly ash is assessed by investigating their resistance to acid attacks. The predominant use of less environmentally sustainable sodium metasilicate (Na2SiO3) and sodium hydroxide (NaOH) in OPG, along with the limited understanding about the influence of solid alkali activators on OPG’s acid resistance propelled the investigation and comparison of acid resistance of OPGs activated using both conventional activators and potential alternatives like sodium aluminate (NaAlO2) and sodium carbonate (Na2CO3). The OPGs developed were exposed to sulphuric acid (H2SO4) solution for 28 days. The MH sample (activated with Na2SiO3 and NaOH) was vulnerable to acid attack, with a 66% compressive strength drop after 5% H2SO4 solution exposure, due to high sorptivity. In contrast, the MA sample (activated with Na2SiO3 and NaAlO2) demonstrated excellent acid resistance, with only a 32% strength reduction, attributed to its Al-rich hydrated gel. The MC sample (activated with Na2SiO3 and Na2CO3) exhibited a 41% strength reduction, where the formation of calcite reduced extensive ion exchange, gradually mitigated deterioration. The residual compressive strength of MA and MC samples increased by 7% and 9% from 7 to 28 days of immersion in 5% H2SO4 solution, respectively. The NaAlO2 and Na2CO3 are potential activators for OPG, serving as alternative construction materials to OPC and traditional geopolymers in acidic environments.

Specifying and Verifying a Transformation of Recursive Functions into Tail-Recursive Functions

It is well known that some recursive functions admit a tail recursive counterpart which have a more efficient time-complexity behavior. This paper presents a formal specification and verification of such process. A monoid is used to generate a recursive function and its tail-recursive counterpart. Also, the monoid properties are used to prove extensional equality of both functions. In order to achieve this goal, the Agda programming language and proof assistant is used to generate a parametrized module with a monoid, via dependent types. This technique is exemplified with the length, reverse, and indices functions over lists.

Type-theoretic approaches to ordinals

In a constructive setting, no concrete formulation of ordinal numbers can simultaneously have all the properties one might be interested in; for example, being able to calculate limits of sequences is constructively incompatible with deciding extensional equality. Using homotopy type theory as the foundational setting, we develop an abstract framework for ordinal theory and establish a collection of desirable properties and constructions. We then study and compare three concrete implementations of ordinals in homotopy type theory: first, a notation system based on Cantor normal forms (binary trees); second, a refined version of Brouwer trees (infinitely-branching trees); and third, extensional well-founded orders.Each of our three formulations has the central properties expected of ordinals, such as being equipped with an extensional and well-founded ordering as well as allowing basic arithmetic operations, but they differ with respect to what they make possible in addition. For example, for finite collections of ordinals, Cantor normal forms have decidable properties, but suprema of infinite collections cannot be computed. In contrast, extensional well-founded orders work well with infinite collections, but the price to pay is that almost all properties are undecidable. Brouwer trees, implemented as a quotient inductive-inductive type to ensure well-foundedness and extensionality, take the sweet spot in the middle by combining a restricted form of decidability with the ability to work with infinite increasing sequences.Our three approaches are connected by canonical order-preserving functions from the “more decidable” to the “less decidable” notions, i.e. from Cantor normal forms to Brouwer trees, and from there to extensional well-founded orders. We have formalised the results on Cantor normal forms and Brouwer trees in cubical Agda, while extensional well-founded orders have been studied and formalised thoroughly by Escardó and his collaborators. Finally, we compare the computational efficiency of our implementations with the results reported by Berger.

Biomechanical evaluation of multiple pelvic screws and multirod construct for the augmentation of lumbosacral junction in long spinal fusion surgery.

Background: Posterior long spinal fusion was the common procedure for adult spinal deformity (ASD). Although the application of sacropelvic fixation (SPF), the incidence of pseudoarthrosis and implant failure is still high in long spinal fusion extending to lumbosacral junction (LSJ). To address these mechanical complications, advanced SPF technique by multiple pelvic screws or multirod construct has been recommended. This was the first study to compare the biomechanical performance of combining multiple pelvic screws and multirod construct to other advanced SPF constructs for the augmentation of LSJ in long spinal fusion surgery through finite element (FE) analysis. Methods: An intact lumbopelvic FE model based on computed tomography images of a healthy adult male volunteer was constructed and validated. The intact model was modified to develop five instrumented models, all of which had bilateral pedicle screw (PS) fixation from L1 to S1 with posterior lumbar interbody fusion and different SPF constructs, including No-SPF, bilateral single S2-alar-iliac (S2AI) screw and single rod (SS-SR), bilateral multiple S2AI screws and single rod (MS-SR), bilateral single S2AI screw and multiple rods (SS-MR), and bilateral multiple S2AI screws and multiple rods (MS-MR). The range of motion (ROM) and stress on instrumentation, cages, sacrum, and S1 superior endplate (SEP) in flexion (FL), extension (EX), lateral bending (LB), and axial rotation (AR) were compared among models. Results: Compared with intact model and No-SPF, the ROM of global lumbopelvis, LSJ, and sacroiliac joint (SIJ) was decreased in SS-SR, MS-SR, SS-MR, and MS-MR in all directions. Compared with SS-SR, the ROM of global lumbopelvis and LSJ of MS-SR, SS-MR, and MS-MR further decreased, while the ROM of SIJ was only decreased in MS-SR and MS-MR. The stress on instrumentation, cages, S1-SEP, and sacrum decreased in SS-SR, compared with no-SPF. Compared with SS-SR, the stress in EX and AR further decreased in SS-MR and MS-SR. The most significantly decreased ROM and stress were observed in MS-MR. Conclusion: Both multiple pelvic screws and multirod construct could increase the mechanical stability of LSJ and reduce stress on instrumentation, cages, S1-SEP, and sacrum. The MS-MR construct was the most adequate to reduce the risk of lumbosacral pseudarthrosis, implant failure, and sacrum fracture. This study may provide surgeons with important evidence for the application of MS-MR construct in the clinical settings.

Biomechanical assessment of lumbar stability: finite element analysis of TLIF with a novel combination of coflex and pedicle screws.

Purpose: Finite element analysis is frequently used for lumbar spine biomechanical analysis. The primary scope of this work is to illustrate, using finite element analysis, how the biomechanical behavior of the transforaminal lumbar interbody fusion (TLIF), along with a novel combination of the interspinous process device (IPD) and pedicle screws, improves lumbar spine stability. Methods: In this study, unilateral pedicle screw fixation (UPSF) and bilateral pedicle screw fixation (BPSF) were used. Four FE models were developed using ANSYS software, as follows: (1) Intact model; (2) TLIF with "U"-shaped Coflex-F IPD (UCF); (3) TLIF with Coflex-F and UPSF (UCF + UPSF); (4) TLIF with Coflex-F and BPSF (UCF + BPSF). The intact model was subjected to four pure moments (10 Nm), and the results were validated with previous literature data. The intact model results correlated well with the literature data, and the model was validated. Three surgical models were subjected to 7.5 Nm four pure moments, flexion (FL), extension (ET), lateral bending (LB), and axial rotation (AR) and a 280N follower load. Results: The surgical model results were compared with the intact model. The comprehensive analysis results show the UCF + BPSF surgical model gave a good advantage on range of motion, cage stress, Coflex-F stress and endplate stress compared among the two models. Conclusion: This study proposes that the UCF + BPSF system helps to reduce the stress on the implant and adjacent endplates and gives very good stability to the lumbar spine under the various static loading conditions.

The 300 MeV proton and heavy ion accelerator complex for SESRI project in China

The 300 MeV proton and heavy ion accelerator complex, which is the key part of SESRI (Space Environment Simulation and Research Infrastructure) project, is currently under construction in China. It comprises an 18 GHz high charge-state ion source, a 108.48 MHz cascaded linac injector consisting of a four-rod RFQ and three interdigital H-mode drift tube linacs, a compact synchrotron, and three irradiation terminals. The extensive ion species from proton to 209Bi32+ will be injected into the synchrotron using multi-turn injection method. The third-order resonance and RF-knockout extraction scheme is adopted to provide quasi-continuous spill for irradiation experiments. The general design of the accelerator complex and simulation results are discussed in this paper.

Extending sleep to improve glycemia: The Family Routines Enhancing Adolescent Diabetes by Optimizing Management (FREADOM) randomized clinical trial protocol

Sleep deficiencies amongst individuals with type 1 diabetes mellitus (T1DM) have been linked with dysregulated glycemic control and greater morbidities. Sleep extension (EXT) has been identified as a viable intervention target to improve adolescent outcomes. The intervention aims to emphasize collaborative work with families to engage in behaviors that increase the likelihood of the youth increasing their sleep duration consistently. This study will randomize up to 175 youth with T1DM and at least one caregiver to either an EXT intervention or a family routines support (FRS) consultation. It is hypothesized that the EXT condition will lead to improvements in sleep, which in turn, will contribute to improved glycemic control. The primary endpoint is improved glycemic control assessed via a continuous glucose monitor (CGM) to ascertain average glucose levels across a week, glycemic variability, and percent time in the target range at one month and HbA1c at three months. Analyses will control for co-morbid conditions, including sleep-disordered breathing and obesity. This study will provide the needed data to support addressing sleep as part of the standards of care in youth with T1DM.

Coactivation During Fatiguing, Maximal, Reciprocal, Isokinetic Forearm Flexion And Extension Muscle Actions Using Mechanomyography

Purpose: Mechanomyography (MMG) has rarely been used to examine coactivation responses during fatiguing tasks. Under some conditions, MMG amplitude (AMP) provides insights into motor unit (MU) recruitment, while MMG mean power frequency (MPF) provides a qualitative description of the global firing rate of the unfused activated motor units. Thus, the purpose of the present study was to use MMG to examine coactivation of the agonist and antagonist muscles during fatiguing reciprocal forearm extension (EXT) and flexion (FLEX) muscle actions. Methods: Ten men (mean ± SD: age = 21.6 ± 1.3 yrs; body mass = 80.9 ± 6.5 kg; height = 179.1 ± 5.9 cm) completed 50 consecutive, maximal, reciprocal, isokinetic forearm EXT and FLEX muscle actions at 60 and 180°·s-1. The AMP and MPF contents of the MMG signals from the biceps (BB) and triceps (TB) were recorded simultaneously throughout the fatiguing task. The MMG and torque values were averaged across 5 consecutive repetitions and normalized to the value from repetition five. A 2 (Speed: 60 and 180°·s-1) x 2 (Muscle: TB and BB) x 2 (Movement: EXT and FLEX) x 10 (Repetitions: 5 - 50) RMANOVA was used to determine mean differences for AMP and MPF. A 2 (Speed) x 2 (Movement) x 10 (Repetitions) RMANOVA was used to determine mean differences for torque. Results: The statistical analyses indicated that for EXT, MMG AMP was greater at 180°·s-1 than 60°·s-1 (p = 0.04) for both the TB and BB. For FLEX, MMG AMP for the TB was greater at 180°·s-1 than 60°·s-1 (p < 0.01), however, there was no significant difference between speeds for the BB. For MMG MPF during EXT, the TB was significantly greater than the BB (p < 0.01). For FLEX, there was no significant difference between muscles. There were significant (p < 0.05) reductions in torque throughout the fatiguing task for both EXT and FLEX. Conclusion: The results indicated that during forearm EXT and FLEX, the faster velocity muscle actions exhibited greater lateral oscillations than the slower velocities, likely due to differences in the contributions of fast and slow fibers to torque production. In addition, the TB exhibited a greater global MU firing rate, as suggested by the MMG MPF responses, than the BB during forearm EXT. Thus, the fatigued-induced decrease in torque was not attributable to changes in coactivation.

The influence of the viscoelastic property of polycarbonate urethane as an artificial disc core material under various physiological motions at the L4-L5 level.

Intervertebral disc (IVD) degeneration is one of the musculoskeletal disorders due to the Degenerative Disc Disease (DDD), that cause low back pain (LBP) and leads to a reduced range of motion. Spinal fusion and arthroplasty are the other surgical procedures that could replace the disc affected by DDD against artificial disc replacement (ADR). This study aims to analyse the biomechanical behaviour of proposed core material as Polycarbonate Urethane (PCU) in the L4-L5 lumbar segment for ADR with Ti-6Al-4V and Co-28Cr-6M as endplate materials and compare it to the performance of an ultra-high molecular weight polyethylene (UHMWPE) core. Finite element methods have been approached to measure the overall stress distribution along with other physiological motions like Flexion (FLEX), Extension (EXT), Axial rotation (AR) and Lateral bending (LB), respectively. Preload of 450 N compressive load, 8 N-m for Flex, 6 N-m for EXT, 6 N-m for AR and 4 N-m for LB are applied. It could be concluded that Ti-6Al-4V - PCU and Co-28Cr-6M - PCU is the best composition for the ADR for the L4-L5 level.

Biomechanical Evaluation of Spinal Column after Percutaneous Cement Discoplasty: A Finite Element Analysis

ObjectiveTo compare the biomechanical properties of percutaneous cement discoplasty (PCD) in the spinal column between different implant‐endplate friction.MethodsA validated L3‐Scarumfinite element (FE) model was modified for simulation. In the PCD model, the L4/5 level was modified based on model 1 (M1) and model 2 (M2). In M1, the interaction between bone cement and endplate was defined as face‐to‐face contact with a friction coefficient of 0.3; in M2, the contact was defined as a Tie constraint. 7.5 N m moments of four physiological motions and axial load of 15, 100 and 400 N preload were imposed at the top of L3. The range of motion (ROM) and interface stress analysis of endplates, annulus fibrosus and bone cement of the operated level were calculated for comparisons among the three models.ResultsThe ROM of M1 and M2 increased when compared with the intact model during flexion (FL) (17.5% vs 10.0%), extension (EX) (8.8% vs −8.8%), left bending (LB) (19.0% vs −17.2%) and left axial rotation (LR) (34.6% vs −3.8%). The stress of annulus fibrosus in M1 and M2 decreased in FL (−48.4% vs −57.5%), EX (−25.7% vs −14.7%), LB (−47.5% vs −52.4%), LR (−61.4% vs −68.7%) and axis loading of 100 N (−41.5% vs −15.3%), and 400 N (−27.9% vs −27.3%). The stress of upper endplate of M1 and M2 increased in FL (24.6% vs 24.7%), LB (82.2% vs 89.5%), LR (119% vs 62.4%) and axis loading of 100 N (64.6% vs 45.5%), and 400 N (58.2% vs 24.3%), but was similar in EX (2.9% vs 0.3%). The stress of lower endplate of M1 and M2 increased in FL (170.9% vs 175.0%), EX (180.8% vs 207.7%), LB (302.6% vs 274.7%), LR (332.4% vs 132.8%) and axis loading of 100 N (350.7% vs 168.6%), and 400 N (165.2% vs 106.7%).ConclusionPercutaneous cement discoplasty procedure could make effect on the mobility or stiffness. The fusion of bone cement and endplate might have more biomechanical advantages, including of the decreasing rate of implant subsidence and dislocation, and the increase spine stability.

Poster 118: The Accuracy of a Smartphone App in Measuring Shoulder Range of Motion

Objectives:Measuring shoulder movements, specifically range of motion (ROM) of the shoulder joint is an important clinical parameter related to glenohumeral disorders and for functional evaluation of the shoulder before and after treatment, which may include surgery. Currently shoulder ROM measurements are performed in an office setting by the provider or alternatively may be performed by a physical therapist, traditionally with the use of a goniometer. The purpose of this study was to determine the accuracy of a smartphone-based digital ROM tool in assessing active shoulder ROM, compared to traditional goniometry measured by a physical therapist in an office setting.Methods:A prospective, non-blinded study was conducted at a single institution (University of St. Augustine, Austin< TX). Thirty (30) eligible and consenting participants with normal shoulder ROM were recruited. Each participant self-assessed their active shoulder ROM using the smartphone App. A physical therapist concurrently measured each participant’s active shoulder ROM using a hand-held goniometer. This concurrent data collection was designed for greater efficiency and minimal bias. Forward flexion (FF), abduction (AB) external rotation (ER), internal rotation (IR) and extension (EX) were measured. Agreement between the smartphone App and goniometric measurements, as well as intra-rater reliability (precision) was assessed using intraclass correlation coefficients (ICC) and Limits of Agreement analysis. Each measurement was performed in duplicate to assess precision. Statistical analysis was performed using R (https://www.r-project.org/)Results:Data were analyzed for 60 shoulders (30 right, 30 left) from 30 participants (mean age was 31.4, 92% female.) The inter-rater reliability between the two methods was excellent for all movements, with ICC ranging from 0.9 to 0.96. For all movements except AB, the mean difference in the measurements between PT and App was less than 1.3 degrees, and the difference was within 6 degrees of the mean differences for 80% of the participants. For AB, the mean difference was 2.08, and the difference was within 15 degrees of the mean difference for 80% of the participants. The intra-rater reliability or precision ranged from good to excellent. For all movements except IR, both PT and App showed excellent intra-rater reliability (ICCs > 0.90). For IR, good intra-rater reliability (ICCs >= 0.75) was observed.Conclusions:These data provide evidence that the smartphone App can be a reliable and valid tool for measuring shoulder ROM. Smartphone Apps enable self-assessment of ROM by patients at the convenience of their home and allow for remote monitoring at zero visit cost to the patient.

Minimal extrathyroidal extension is associated with lymph node metastasis in single papillary thyroid microcarcinoma: a retrospective analysis of 814 patients

BackgroundExtrathyroidal extension (ETE) is considered a major prognostic factor in papillary thyroid carcinoma (PTC). Patients with gross ETE are at increased risk of recurrence and mortality. The importance of minimal ETE still remains controversial, especially in patients with papillary thyroid microcarcinoma (PTMC). The purpose of this study was to evaluate the association between ETE and lymph node (LN) metastasis in single PTMC.MethodsA retrospective analysis was performed of 1994 patients underwent thyroidectomy for PTC between 2012 and 2016 in a single institution. Patients with combined thyroid carcinoma of other types and those who underwent completion thyroidectomy were excluded. After further exclusion of PTC larger than 1 cm and multifocal tumors, 814 patients with single PTMC were included in the study.Results72.9% patients had no ETE, 25.1% minimal ETE, and 2.1% gross ETE. ETE was associated with lymphatic invasion, perineural invasion, and vascular invasion. Patients with minimal and gross ETE were also more likely to have LN metastasis, including lateral neck metastasis, compared to those without ETE. In univariate analysis, LN metastasis was associated with male gender, conventional PTC, lymphatic invasion, perineural invasion, and ETE. In multivariate analysis, male gender (OR = 1.987; 95% CI 1.369–2.884), lymphatic invasion (OR = 4.389; 95% CI 1.522–12.658), perineural invasion (OR = 6.545; 95% CI 1.262–33.948), and minimal ETE (OR = 1.852; 95% CI 1.298–2.643) were found to be independent risk factors of LN metastasis.ConclusionsMinimal ETE is associated with LN metastasis in single PTMC, compared to no ETE. Minimal ETE should be considered in the management of patients with single PTMC, whether surgical or during active surveillance.