Force Profiles Research Articles

Formulation development and evaluation of carbopol-incorporated mucoadhesive thermoreversible gels of sucralfate for rectal drug delivery

Objective : The present study describes the preparation and evaluation of a Poloxamer 188 (P188)-based thermoreversible gel using Carbopol 934P (C934P) as a mucoadhesive polymer of Sucralfate for enhancing the bioavailability and to avoid the first-pass metabolism. Methods: Eight formulations (F1-F8) were prepared using cold method. The prepared gels were characterized by pH, drug content, spreadability, mucoadhesive force, gelation temperature, and drug release profile. Thermoreversibility of P188/C934P gel was demonstrated by rheological studies. The drug-polymer compatibility was studied using Fourier transform infrared (FTIR). The incorporation of carbopol into P188 gel also reduced the amounts of drug released from the gel formulations. Results: FT-IR studies revealed that there are no interactions between the drug and polymers. Drug content of gels was estimated and the results were found to be satisfactory. In vitro dissolution studies revealed a good drug release from the gels. The drug release was higher in formulations F5 and F6 and lower in F4, F7, and F8 formulations. These findings suggested that developed thermoreversible gels could be used as promising dosage forms to rectal drug delivery for prolonged periods in the management of hemorrhoids.

Evaluation of Constrained and Restrained Molecular Dynamics Simulation Methods for Predicting Skin Lipid Permeability.

Recently, molecular dynamics (MD) simulations have been utilized to investigate the barrier properties of human skin stratum corneum (SC) lipid bilayers. Different MD methods and force fields have been utilized, with predicted permeabilities varying by few orders of magnitude. In this work, we compare constrained MD simulations with restrained MD simulations to obtain the potential of the mean force and the diffusion coefficient profile for the case of a water molecule permeating across an SC lipid bilayer. Corresponding permeabilities of the simulated lipid bilayer are calculated via the inhomogeneous solubility diffusion model. Results show that both methods perform similarly, but restrained MD simulations have proven to be the more robust approach for predicting the potential of the mean force profile. Critical to both methods are the sampling of the whole trans-bilayer axis and the following symmetrization process. Re-analysis of the previously reported free energy profiles showed that some of the discrepancies in the reported permeability values is due to misquotation of units, while some are due to the inaccurately obtained potential of the mean force. By using the existing microscopic geometrical models via the intercellular lipid pathway, the permeation through the whole SC is predicted from the MD simulation results, and the predicted barrier properties have been compared to experimental data from the literature with good agreement.

A Multi-Systems Approach to Human Movement after ACL Reconstruction: The Musculoskeletal System.

Several negative adaptations to the musculoskeletal system occur following anterior cruciate ligament (ACL) injury and ACL reconstruction (ACLR) such as arthrogenic muscle inhibition, decreased lower extremity muscle size, strength, power, as well as alterations to bone and cartilage. These changes have been associated with worse functional outcomes, altered biomechanics, and increased risk for re-injury and post-traumatic osteoarthritis. After ACL injury and subsequent ACLR, examination and evaluation of the musculoskeletal system is paramount to guiding clinical decision making during the rehabilitation and the return to sport process. The lack of access many clinicians have to devices necessary for gold standard assessment of muscle capacities and force profiles is often perceived as a significant barrier to best practices. Fortunately, testing for deficits can be accomplished with methods available to the clinician without access to costly equipment or time-intensive procedures. Interventions to address musculoskeletal system deficits can be implemented with a periodized program. This allows for restoration of physical capacities by adequately developing and emphasizing physical qualities beginning with mobility and movement, and progressing to work capacity and neuromuscular re-education, strength, explosive strength, and elastic or reactive strength. Additional considerations to aid in addressing strength deficits will be discussed such as neuromuscular electrical stimulation, volume and intensity, eccentric training, training to failure, cross-education, and biomechanical considerations. The American Physical Therapy Association adopted a new vision statement in 2013 which supported further development of the profession’s identity by promoting the movement system, yet validation of the movement system has remained a challenge. Application of a multi-physiologic systems approach may offer a unique understanding of the musculoskeletal system and its integration with other body systems after ACLR. The purpose of this clinical commentary is to highlight important musculoskeletal system considerations within a multi-physiologic system approach to human movement following ACLR.Level of Evidence5

Conceptual Frameworks and Theoretical Models for the Psychological Selection of Future Officers

Abstract The objective of this paper is to present the approaches to the elaboration of psychological profiles of military forces and specialties and the choice of the theoretical model that underlies the elaboration/selection of psychological assessment tools. The theoretical models underpinning the psychological assessment activity have been extensively studied and conclusive scientific data and evidence have been obtained in empirical studies conducted over several years. For example, the multiple intelligences model, which accepts that people have different and distinct cognitive strengths and styles, highlights and takes into account the most representative psychological characteristics of the person being assessed in order to propose the most optimal match with the requirements of the military branch/specialty in which he/she can develop.

The evolution of two distinct strategies of moth flight.

Across insects, wing shape and size have undergone dramatic divergence even in closely related sister groups. However, we do not know how morphology changes in tandem with kinematics to support body weight within available power and how the specific force production patterns are linked to differences in behaviour. Hawkmoths and wild silkmoths are diverse sister families with divergent wing morphology. Using three-dimensional kinematics and quasi-steady aerodynamic modelling, we compare the aerodynamics and the contributions of wing shape, size and kinematics in 10 moth species. We find that wing movement also diverges between the clades and underlies two distinct strategies for flight. Hawkmoths use wing kinematics, especially high frequencies, to enhance force and wing morphologies that reduce power. Silkmoths use wing morphology to enhance force, and slow, high-amplitude wingstrokes to reduce power. Both strategies converge on similar aerodynamic power and can support similar body weight ranges. However, inter-clade within-wingstroke force profiles are quite different and linked to the hovering flight of hawkmoths and the bobbing flight of silkmoths. These two moth groups fly more like other, distantly related insects than they do each other, demonstrating the diversity of flapping flight evolution and a rich bioinspired design space for robotic flappers.

Functional Testing Using a Force Motion Capture Device for Hand Surgery Outcome Assessment: A Proof of Concept.

Osteoarthritis is the leading cause of loss of hand function in America and most commonly affects the carpometacarpal joint of the thumb. Although medication and exercise are possible treatments in mild cases, in cases of severe thumb osteoarthritis, surgery may be the only treatment option. One surgical approach is Mini TightRope (Arthrex, Inc., Naples, Fla.) suspensionplasty, which uses a suture wire to attach the base of the thumb metacarpal to the second metacarpal after removal of the trapezium. Current methods of clinical outcome assessment following hand surgery, such as questionnaires and goniometry, do not provide data that are well suited for improving surgical or mechanical design. Also, current in vivo studies investigating changes following this operation have primarily focused on pain, and not function. Surgical design and surgical devices require engineering, and data from patient outcomes by questionnaires and current clinical tests may not provide data that are well suited to improving surgical or mechanical design. To improve patient care and to foster device design, it is critical to understand how the function of the thumb—specifically, motion and forces—changes because of surgery to give patients the best treatment possible. We have developed a force motion capture device that records the joint range of motion of the thumb coupled with measurement of applied forces at different points within the range or motion. The goal of this work was to illustrate how the force motion capture device could be used to quantify function preoperatively and postoperatively for basal joint arthroplasty. A patient who was scheduled for Mini TightRope suspensionplasty was tested before surgery, 6 weeks after surgery, and again 12 weeks after surgery. Thumb forces and the kinematic range of motion were measured over the kinematic space and analyzed to determine changes between preoperatively and postoperatively in magnitude, the range of force directions, and the volume of the kinematic space used to apply forces (Fig. 1).Fig. 1.: Force motion capture. Force capabilities were measured using both a six-axis load cell and motion capture at multiple positions and directions; shown are palm at (left) 0 degrees (horizontal) and force directed medially (right) and palm at 60 degrees with respect to horizontal with force directed toward the ground. Range of motion was also measured using reflective markers and motion capture and through full flexion of the metacarpophalangeal and interphalangeal joints of the thumb and full ranges of opposition and abduction.Functional changes in the participant’s hand were quantified using force motion capture. Figure 2 was the result of force motion capture for the individual. It describes how the participant’s kinematic range of motion (gray space) changed relative to a healthy individual (white space), and how the forces that participant was able to apply changed because of force application (colored arrows). Overall, the forces that this participant could apply decreased in both magnitude and volume of the kinematic space used to apply the force, drastically following the surgery, then returned to a similar but not significantly improved degree of function after 12 weeks from their initial condition. The range of directions the participant was able to apply forces in did not change because of the surgery.Fig. 2.: Differences in force production for one participant. Visualized force profiles over the range of motion for a participant at each testing point. The white space is that from a healthy thumb (two-dimensional projection). The grey-shaded region is the kinematic space from the participant at each time point (left, before surgery; center, 6 weeks after surgery; right, 12 weeks after surgery and at completion of physical therapy). The colored arrows indicate the force production, with hotter colors indicating more force. The direction of the arrow indicates direction of the force application.Force motion capture provides a descriptive, accurate, and efficient method to measure the functional abilities of the thumb and compare them over time. These functional test results make force motion capture a novel method of quantifying functional changes in the thumb and can be used track function throughout recovery and to compare different surgical treatments and device designs to determine which leads to the most function recovered. DISCLOSURE Dr. Clarkson has previously worked with Arthrex, the developer of the surgical device. Drs. Drost and Bush have no financial disclosures to report.

Sonitictis moralesi, gen. et sp. nov, a new hypercarnivorous and durophagous mustelid from middle Miocene Tunggur Formation, Inner Mongolia, China and its functional morphology

ABSTRACT We name a rare, hypercarnivorous and durophagous mustelid Sonitictis moralesi, new genus and species, in honour of Jorge Morales for his contributions to carnivore palaeontology. Sonitictis moralesi is from the middle Miocene Tunggur Formation of Inner Mongolia, China (Tunggurian Land Mammal age). S. moralesi has a short and robust jaw that deepens slightly behind the m1 and possesses a shallow groove at its ventral surface. Dentally, it has robust premolars and highly hypercarnivorous m1 that has lost the metaconid and a trenchant talonid. Known by three jaw fragments, knowledge of this new mustelid is still poor and its relationship uncertain. However, based on its possession of a ventral groove, robust premolars and hypercarnivorous first molar, we tentatively place it in the subfamily Mellivorinae, which includes modern Mellivora capensis (honey badger) and extinct species of Eomellivora, plus others. We conducted mandibular force profile analyses on one S. moralesi specimen and compared bite force estimates to several specimens of E. piveteaui, E. wimani and M. capensis. The results suggest that Sonitictis likely was a more capable predator and consumer of vertebrate prey than the extant Mellivora, reaching the low end of the bite force estimates for the larger and more robust Eomellivora.

Effects of plate wear on bar forces and fiber properties in a mill scale LC-refiner

Abstract A set of piezo electric force sensors is implemented in a 52-inch mill-scale low consistency refiner to explore the effect of refiner plate wear on bar force sensor measurements. The sensor replaces a short length of a stator bar and measures normal and shear forces applied during the passage of each rotor bar. In previous work with this type of force sensor, force profiles for individual bar passing events (BPE) were investigated. In the work presented here, force profiles for individual BPEs are identified based on key features in the time domain force data. The individual bar force profiles are classified as single peak events which feature one peak corresponding to the fiber compression force and as dual peak events corresponding to fiber compression force and the corner force. The bar passing events are then analysed, based on dual peak ratio and time to peak of the early peak in the dual peak events. Force measurements are evaluated over the full run time of a set of refiner plates. Findings are compared with refiner plate wear measurements and discharge fiber analysis. It is shown that the decrease in the prevalence of the corner force correlates with the wear of the leading edge of the refiner bars or bar rounding of the run time of the refiner plate. This is accompanied by a decrease in plate performance which is represented by a decrease in fiber length and freeness reduction for the same refiner load.

Single Cell Micro-Pillar-Based Characterization of Endothelial and Fibroblast Cell Mechanics

Mechanotransduction, the ability of cells to sense and respond to the mechanical cues from their microenvironment, plays an important role in numerous cellular processes, ranging from cell migration to differentiation. Several techniques have been developed to investigate the underlying mechanisms of mechanotransduction, in particular, force measurement-based techniques. However, we still lack basic single cell quantitative comparison on the mechanical properties of commonly used cell types, such as endothelial and fibroblast cells. Such information is critical to provide a precedent for studying complex tissues and organs that consist of various cell types. In this short communication, we report on the mechanical characterization of the commonly used endothelial and fibroblast cells at the single cell level. Using a micropillar-based assay, we measured the traction force profiles of these cells. Our study showcases differences between the two cell types in their traction force distribution and morphology. The results reported can be used as a reference and to lay the groundwork for future analysis of numerous disease models involving these cells.

Abstract 10378: A Novel Selectively Flexible Mitral Annuloplasty Ring Designed Based on Human Imaging with Superior Performance in Hemodynamics, Biomechanics, and Annular Dynamics - A Comprehensive Bench to in vivo Large Animal Analysis

Introduction: We designed a novel mitral annuloplasty ring based on healthy human imaging to allow for the mitral valve (MV) annular conformational changes while restricting the anteroposterior (AP) distance. The objectives were to evaluate ex vivo biomechanics of the novel ring and to validate the annular dynamics after ring implantation in vivo. Methods: Cardiac MRI exams were obtained for 3 healthy volunteers. The MV annulus was tracked (Fig. A-C). Based the imaging data, a novel ring was manufactured (Fig. D-F). An ex vivo annular dilation model of mitral regurgitation was used in a left heart simulator (Fig. G, H) to measure hemodynamics and chordal forces at dilated baseline and after repair using the novel, rigid, and flexible rings in 5 porcine MVs. Novel (n = 6) or rigid rings (n = 5) were implanted into male Dorset sheep. Pre- and post-operative cardiac MRI exams were analyzed. Results: Repair using the novel, rigid, and flexible ring reduced regurgitation fraction from 30.0 ± 5.8% at dilated baseline to 4.7 ± 2.7%, 2.4 ± 3.2%, and 17.8 ± 10.0% ( p < .0001, Fig. I-N ). Peak forces on the primary chordae decreased after ring annuloplasty repair ( p < .0001, Fig. O ). The novel ring also showed lower peak forces compared to the rigid ring (p = .03) in secondary chordae ( Fig. P ). MV annular motion was preserved in vivo using the novel ring but restricted to a planar geometry using the rigid ring ( Fig. Q-S ). Annular height to intercommissure ratio at midsystole were similar pre-repair (0.2 ± 0.1) and after novel ring repair (0.2 ± 0.0, p = .89). The variance of AP distance during the cardiac cycle was similar between the novel (0.4 ± 0.3) and rigid ring (0.5 ± 0.1, p = .58). Conclusions: This novel mitral annuloplasty ring demonstrated excellent capability in reducing AP dimension and repairing regurgitation with a superior chordal force profile while facilitating the annular flexible motion. Future studies will focus on evaluating repair durability and effect on left ventricular remodeling.

A Versatile and Simple Approach to Electrochemical Colloidal Probes for Direct Force Measurements.

The colloidal probe technique, which is based on micrometer-sized colloidal particles that are attached to the end of a cantilever, revolutionized direct force measurements by atomic force microscopy (AFM). Its major advantages are a defined interaction geometry and a high force sensitivity. Here, we present a versatile and simple approach for preparing spherical electrodes in the micrometer range on an otherwise insulated AFM cantilever. Thereby, it becomes possible to combine direct force measurements and potentiostatic control of the probe for various types of electrode materials. Two examples for the use of such electrochemical colloidal probes (eCP) are presented: First, on soft, conductive films of poly(3,4-ethylenedioxythiophene) doped with poly(styrenesulfonate) (PEDOT:PSS) the adhesion behavior was studied. The current through the contact area between the probe and film remained constant until the jump-out of contact, indicating a constant geometrical contact area. Second, the long-range forces due to diffuse layer overlap between an eCP and a glass surface have been determined as a function of the externally applied potential. The resulting interaction force profiles are in good agreement with those calculated based on charge regulation and solutions of the full Poisson-Boltzmann equation.

Numerical study of hydrodynamic resistance on a sportive sprint hull

In this work we perform a numerical study on the flow around the hulls of competition kayaks with the aim of predicting accurate drag forces. The numerical simulations were first performed using the Wigley hull geometry, a typical validation case for flows around marine vessels. The total drag force and wave profiles of the hull were determined for different Froude numbers and compared with experimental measurements. After validation and verification of the numerical method, the flow around two competition sprint kayaks was investigated. The drag force was calculated and compared with experimental and numerical data

An Efficient One-Step Moment Balancing Algorithm for Computing Medial and Lateral Knee Compartment Contact Forces.

The knee adduction moment is associated with the progression of knee osteoarthritis (OA). The adduction moment reflects the net effect of muscles, passive tissues and bone-on-bone contact forces. Medial compartment OA is more common than lateral and therefore our ability to correctly partition bone-on-bones forces across the medial and lateral compartments is key to understanding mechanical factors associated with the onset and progression of knee OA. In this technical brief we present an efficient one-step moment balancing algorithm linking the sagittal and frontal planes in the determination of musculotendon forces. Novel to the one-step approach is the introduction of a penalty function limiting total compressive force from acting in the lateral compartment when the internal moment is net abduction (i.e., external knee adduction). Medial and lateral knee contact forces were computed using the one-step moment balancing algorithm for 10 subjects walking at a self-selected pace and compared to values determined using a well-established two-step frontal moment balancing approach. Overall, average peak differences in magnitude and timing were small and the ensemble-averaged contact force profiles were similar between methods. The only statistical difference was slightly larger (0.2 BWs) peak medial contact force for the one-step method during the first half of stance, however these differences are small relative to peak values and would not likely alter interpretation of the data. The 1-step moment balancing method is a more efficient methodology for computing medial and lateral knee contact forces that can be used in place of two-step frontal plane moment balancing.

Nanometer-Scale Force Profiles of Short Single- and Double-Stranded DNA Molecules on a Gold Surface Measured Using a Surface Forces Apparatus.

Using a surface forces apparatus (SFA), we have studied the nanomechanical behavior of short single-stranded and partially and fully double-stranded DNA molecules attached via one end to a self-assembled monolayer on a gold surface. Our results confirm the previously proposed "mushroom-like" polymer structure for surface-attached, single-stranded DNA at low packing density and a "brush-like" structure for the same construct at higher density. At low density we observe a transition to "rigid rod" behavior upon addition of DNA complementary to the surface-attached single strand as the fraction of molecules that are double-stranded increases, with a concomitant increase in the SFA-observed thickness of the monolayer and the characteristic length of the observed repulsive forces. At higher densities, in contrast, this transition is effectively eliminated, presumably because the single-stranded state is already extended in its "brush" state. Taken together, these studies offer insights into the structure and physics of surface-attached short DNAs, providing new guidance for the rational design of DNA-modified functional surfaces.

A smart ink pen for spiral drawing analysis in patients with Parkinson's disease.

Handwriting skills could be highly impaired in patients affected by Parkinson's disease (PD), and for this reason its analysis had always been considered relevant. In handwriting assessment, Archimedes spiral drawing is one of the most proposed tasks, due to its peculiar shape and ease of execution. In the last decades, digitizing tablets had been widely employed for the evaluation of the spiral performance, providing a cheap and non-invasive way to gather quantitative information, to be combined with the classical clinical examination. Despite this advantage, such approach cannot easily be adopted in an unsupervised scenario and lacks the natural feel of the traditional pen-and-paper approach. This work aims at overcoming these limitations by employing a smart ink pen, designed to write on paper and instrumented with inertial and force sensors, to automatically collect data related to spiral drawing execution of PD patients (n=30) and age-matched healthy controls (n=30). From the raw data, several time and frequency domains features were extracted and compared between the groups. The statistical analysis revealed some significant differences, showing less smooth acceleration and force profiles for PD patients. However, given the heterogeneous symptoms presented by the PD cohort, a detailed analysis of exemplifying PD patients was conducted, showing the ability of Archimedes spiral drawing to capture and quantify PD characteristic features.Clinical Relevance- Among the first clinical manifestations of the pathology, handwriting impairment appears in PD patients. It is often underestimated and not investigated properly. This easy-to-use tool could be very useful as a large-scale screening, but also for treatment efficacy evaluation and for the identification of PD subgroups.

Impact responses of precast hollow reinforced concrete beams with prestress tendons using high-fidelity physics-based simulations

This study investigates the dynamic response, damage mechanisms, and residual capacity of precast hollow reinforced concrete beams with prestress tendons (HRCBPT) under impact loads by using High-Fidelity Physics-Based (HFPB) finite element (FE) models. The accuracy of the numerical model developed in this study has been fully calibrated against two different drop-weight impact tests available in open literature, including a scaled hollow reinforced concrete beam (HRCB) and a full-scale reinforced concrete (RC) beam. The results in this study show that under low to moderate impact loads, the flexural cracks and global deformation of the HRCBPT are similar to the hollow beam with normal reinforcement. Under high impact loads, although these beams exhibit similar diagonal shear cracks near the impact location, the HRCBPT experiences more local concrete spalling damage on the bottom flange, higher residual capacity index, and smaller reaction force at supports owing to the contribution of the initial prestress force. The results also suggest that the maximum compressive stress at the bottom flange of the section should be smaller than 17.6% of its compressive strength in order to maximise the beam’s impact-resistant capacity, while the prestress level in the tendon should be lower than 65% of the tendon yield strength to prevent premature failure under moderate impact conditions. Furthermore, different combinations of the impact velocity and impact mass would generate different impact force profiles on the beam resulting in dissimilar impact responses and residual capacity. In the design analysis, together with the critical impact location at the mid-span, the impact location close to the supports which may cause critical shear response of the beam, also needs be considered. In this study, the impact in the vicinity of the support yields the most severe damage to the beam resulting in the lowest residual capacity.

Improving uniaxial compressive strength estimation of carbonate sedimentary rocks by combining minimally invasive and non-destructive techniques

Uniaxial compressive strength (UCS) is the most used parameter to measure rock strength. However, restrictions in sampling large volume of material, the need of very large set of results and onsite characterisation of UCS non-destructively are requirements in many scientific and engineering investigations. The estimation of UCS from a single non-destructive or minimally invasive technique (NDT) may result incomplete because each NDT is sensitive to different compositional and textural factors. This paper combines open porosity, P-wave velocity, Leeb hardness and micro-drilling resistance force to estimate USC for a wide range of carbonate sedimentary rock types with different petrographic characteristics. Results reveal that mineralogical composition significatively affects micro-drilling resistance force profiles and P-wave velocity values, especially for quartz-bearing rocks. In addition, texture controls substantially the reproducibility of tests sensible to rock surface properties, such as Leeb hardness and micro-drilling resistance force. Fifteen simple and multiple expressions for UCS are fitted. Linear expressions have shown better coefficients of determination (R 2 ) than non-linear equations because of the linearity shown by individual parameters. Curve fitting improves as the number of petrophysical parameters increase in the multiple linear regression analysis. The best correlation is found when the equation incorporates all the mechanical parameters obtained non-destructively as well as open porosity (R 2 = 0.910). Leeb hardness is always the most significant variable of the fitted regressions and its addition into multiple linear equations causes an increase of R 2 . Open porosity also improves R 2 whereas drilling force and P-wave velocity have a lower statistical weight in the expressions. The UCS estimation from all NDT, without considering open porosity, shows a good correlation (R 2 = 0.899), which presents the advantage that they can be obtained non-destructively with portable equipment and can provide a numerous set of results at relatively low cost. • Compositional and textural factors affect differently to the mechanical parameters. • Leeb hardness is the most significant variable in the fitted regressions. • The best UCS estimation incorporates all NDT parameters as well as open porosity. • Portability is one of the main advantages of NDTs.

Deceleration Training in Team Sports: Another Potential \u2018Vaccine\u2019 for Sports-Related Injury?

High-intensity horizontal decelerations occur frequently in team sports and are typically performed to facilitate a reduction in momentum preceding a change of direction manoeuvre or following a sprinting action. The mechanical underpinnings of horizontal deceleration are unique compared to other high-intensity locomotive patterns (e.g., acceleration, maximal sprinting speed), and are characterised by a ground reaction force profile of high impact peaks and loading rates. The high mechanical loading conditions observed when performing rapid horizontal decelerations can lead to tissue damage and neuromuscular fatigue, which may diminish co-ordinative proficiency and an individual’s ability to skilfully dissipate braking loads. Furthermore, repetitive long-term deceleration loading cycles if not managed appropriately may propagate damage accumulation and offer an explanation for chronic aetiological consequences of the ‘mechanical fatigue failure’ phenomenon. Training strategies should look to enhance an athlete’s ability to skilfully dissipate braking loads, develop mechanically robust musculoskeletal structures, and ensure frequent high-intensity horizontal deceleration exposure in order to accustom individuals to the potentially damaging effects of intense decelerations that athletes will frequently perform in competition. Given the apparent importance of horizontal decelerations, in this Current Opinion article we provide considerations for sport science and medicine practitioners around the assessment, training and monitoring of horizontal deceleration. We feel these considerations could lead to new developments in injury-mitigation and physical development strategies in team sports.

Health Conditions Among Special Operations Forces Versus Conventional Military Service Members: A VA TBI Model Systems Study.

To examine traumatic brain injury (TBI) characteristics and comorbid medical profiles of Special Operations Forces (SOF) Active Duty Service Member/Veterans (ADSM/Vs) and contrast them with conventional military personnel. The 5 Veterans Affairs (VA) Polytrauma Rehabilitation Centers. A subset of participants in the VA TBI Model Systems multicenter longitudinal study with known SOF status. These included 157 participants who identified as SOF personnel (average age = 41.8 years; 96% male, 81% active duty), and 365 who identified as Conventional Forces personnel (average age = 37.4 years; 92% male, 30% active duty). Retrospective analysis of prospective cohort, cross-sectional. The Health Comorbidities Interview. SOF personnel were more likely to have deployed to a combat zone, had more years of active duty service, and were more likely active duty at time of TBI. SOF personnel were more likely to have had mild TBI (vs moderate/severe) and their TBI caused by violent mechanism. SOF personnel had a higher number of comorbidities, with more diagnoses of chronic pain, osteoarthritis, hyperlipidemia, hip fractures, and obstructive sleep apnea. SOF personnel are at a higher risk for multimorbidity after TBI. Current rehabilitation practices should incorporate early screening and treatment of common conditions in this population, while future practices may benefit from a focus on prevention.

Interpretation of force profiles in mill-scale LC refining

Abstract A set of piezo electric force sensors is implemented in a 52-inch mill-scale low consistency refiner to explore the effect of varying operating conditions on bar force profiles. The sensor replaces a short length of a stator bar and measures normal and shear forces applied during the passage of each rotor bar. In previous work with this type of force sensor a rotary encoder was used to investigate force profiles for individual bar passing events (BPE) on a 16-inch laboratory-scale refiner. In the work presented here, force profiles for individual BPEs are identified based on key features in the time domain force data. The individual bar force profiles are classified as single peak events which feature one peak corresponding to the fiber compression force and as dual peak events corresponding to fiber compression force and the corner force. The bar passing events are then analysed based on their mean force profiles and their dual peak ratio in the bar passing event. Findings are compared and validated by previous work on bar force profiles. It is shown that dual peak events which are considered to represent the corner force, are present through out the whole range of refining and increase with increased refining energy. This increases the understanding of the way corner force contributes to the refining process. Furthermore, it is found that different radial positions on the stator plate are subjected to different force profiles. This is thought to be due to the difference in tangential speed and a change in the fiber and floc material properties at different radial positions.