Rotation Test Research Articles

Poster 231: Lateral Extra-articular Tenodesis Provides Supraphysiological Restraint to Internal Tibial Rotation: In vitro Biomechanical Assessment

Objectives:Lateral extra-articular tenodesis (LET) reduces ACL graft failure rates two years after surgery when performed as an adjunct to ACL reconstruction (ACLR). Interestingly, previous biomechanical studies have shown that LET may reduce tibial rotation beyond that of the intact knee, while others found no such kinematic overconstraint. Parameters of ligament engagement have proven useful in characterizing the biomechanical function of the ACL and the anterolateral ligament; however, they have not been used to describe the biomechanics of LET. In this study, we compared engagement parameters (engagement point, in situ stiffness, and tissue force at peak applied load) of an LET-reconstructed knee compared to the native lateral tissues in response to an internal rotation torque at 0°, 30°, 60°, and 90° of knee flexion.Methods:Seven cadaveric knees (mean age: 39 ± 12; range: 28-54; 4 male) were mounted to a robotic manipulator. The robot applied an internal rotation torque of 5 Nm while monitoring the resulting internal tibial rotation (ITR) (in degrees). Each knee was tested following a bone-patellar tendon-bone ACL reconstruction with intact lateral tissues (consisting of the anterolateral ligament and Kaplan fibers) and after sectioning these tissues and performing LET (modified Lemaire technique). Resultant forces carried by the native lateral tissues and the LET were determined via superposition. The parameters of engagement were determined for both the native lateral tissues and the LET and compared via two-way repeated measures ANOVA (p < 0.05).Results:During an internal rotation test at full extension (0° of flexion), both the LET-reconstructed and native lateral tissues did not engage. At 30°, 60°, and 90° knee flexion, the native lateral tissues exhibited more in situ slack than the LET-reconstructed lateral tissues. Specifically, the native lateral tissues had 8° (p < 0.001), 13° (p < 0.001), and 14° (p < 0.001) more in situ slack than the LET-reconstructed lateral tissues at 30°, 60°, and 90° knee flexion, respectively. At 30° of flexion, the LET-reconstructed lateral tissues were 9° (p < 0.001) and 10° (p < 0.001) more slack than at 60° and 90° knee flexion. Across all three tested knee flexion angles (30°, 60°, and 90°), the LET-reconstructed lateral tissues had greater in situ stiffness than the native lateral tissues. The LET carried greater force at the peak applied internal rotation torque by 29 N at 30° of flexion (p = 0.006), but no statistical differences were identified at the other flexion angles.Conclusions:LET creates a supraphysiologic restraint to the native lateral tissues by engaging with less internal tibial rotation than the native lateral tissue at all flexion angles tested but full extension. The LET also carried greater force at the peak applied load and had a greater in situ stiffness at 30° of flexion than the native lateral tissues. On the whole, LET is a supraphysiological restraint to internal tibial rotation at 30° of flexion. The engagement point of LET may be modified surgically by altering the flexion angle, degree of tibial rotation at which the tenodesis is fixed, and/or the tension applied. Thus, discrepancies between previous biomechanical studies may arise from variations in one or more of these modifiable surgical parameters.Figure 1.Mean tissue force versus internal tibial rotation response of the LET and native lateral tissues with applied internal rotation torque at 0,30,60, and 90° of knee flexion. Whiskers represent one standard deviation. Engagement point denoted in yellow. Tissue force at peak applied internal tibial rotation torque denoted in blue.

Paper 93: Biomechanical Comparison of Tibiotalar Contact Pressures After Syndesmosis Injury With or Without Deltoid Ligament Repair

Objectives:Recent studies have stressed the important role of the deltoid ligament in maintaining global ankle stability. However, controversy remains around whether deltoid ligament repair is necessary in addition to syndesmotic repair when addressing injuries that disrupt both the syndesmosis and deltoid ligament. The purpose of this study was to measure differences in tibiotalar joint contact pressures and tibio-talar torsional stability in the presence of deltoid ligament injury, syndesmotic injury, and after their respective repairs using a cadaveric model. Our hypotheseis were 1) injury to the syndesmoosis and deltoid would increase contact pressures and decrease torsional stability, 2) repaired injuries would restore biomechanics to near native state, and 3)that there would be similar tibiotalar contact pressures and torsional stability with syndesmosis repair alone compared to syndesmosis and deltoid ligament repair.Methods:Twelve fresh-frozen human cadaveric lower extremity specimens with intact ankle joints were randomized and tested under a series of conditions: 1) intact syndesmosis and deltoid, 2) sectioning of syndesmosis or deltoid, 3) sectioning of both the syndesmosis and deltoid, 4) repair of syndesmosis or deltoid, 5) repair of both the syndesmosis and deltoid. In one group, the syndesmosis was sectioned and repaired first and in the other the deltoid was sectioned and repaired first. The syndesmosis was repaired with a single high-tensile strength suture mechanism (TightRope, Arthrex), and deltoid ligament repairs were performed with a single suture anchor (FiberTak, Arthrex). Specimens were tested under each condition with 800 N axial compression load, followed by cyclic torsional preconditioning of 5 Nm internal tibial torque (i.e., external foot rotation) at a rate of 2.5 Nm/s, and then a single rotation test of 7.5 Nm internal tibial torque at 1 Nm/s under 800 N axial compression load on a servohydraulic mechanical testing system. Contact pressures within the tibiotalar joint were measured with a digitized pressure sensor film (Tekscan, Boston MA), and coronal plane motion about the tibia was measured in angular displacement.Results:There was no significant difference in peak contact pressures between conditions except when the comparing an isolated deltoid ligament injury to a combined deltoid and syndesmosis injury (4.43±1.33MPa vs 2.67±0.45MPa, p=0.038). Total contact area was less following syndesmosis repair in isolation (609.55±312.37mm2) and combined syndesmosis and deltoid repair (598.28±181.47mm2) compared to all other conditions (p<0.001). There was also a decrease in total contact area compared to native state when the deltoid was repaired in isolation (951.51±72.79mm2 vs 888.72±105.74mm2, p=0.027). The mean external rotation angle was greater when the syndesmosis (15.67±5.39°), deltoid (13.21±3.28°), and both injuries combined (16.59±4.01°) compared to native state (8.55±2.02°), however these values did not achieve statistical significance. Additionally, There was no statistically significant difference in external rotation angle between isolated syndesmosis, isolated deltoid, or combined repairs.Conclusions:These findings demonstrate that ankle contact pressures and torsional stability do not differ significantly when a deltoid ligament repair is performed in conjunction with a syndesmosis repair for a purely ligamentous injury. However, the change in contact area following syndesmosis repair may play a role in the development of post-traumatic arthritis. This finding reinforces the importance of striving for an anatomic syndesmotic reduction, and care should be taken not to over-reduce the syndesmosis during repair.

Comparison of Mental Rota tion and Reaction Time Performances In Deaf Athletes And Non-Athletes

The coordination of perceptual-cognitive and motor processes is one of the main components determining sports performance. However, many factors affect these components, such as disability, gender, doing sport, etc. The aim of this study is to determine the mental rotation and reaction time performance of deaf athletes and non-athletes in terms of doing sport and gender. 42 heavy hearing impaired (90+ dB) students, 22 males, and 20 females, participated in the study. 22 of the participants were deaf basketball athletes, and 20 were deaf non-athletes. The participants' mental rotation and reaction time performance measurement tests were carried out with a computer-based software MP36 (Biopac System, USA). Independent Samples T-test and (multivariate) Manova tests were performed to evaluate the data. There were no statistically significant differences between the groups, neither mental rotation nor reaction time variables, in terms of doing sport. However, there were statistically significant differences between the groups in both mental rotation and reaction time variables regarding gender and doing sport. As a result, it was found that male athletes are better than women who are not athletes in some of the mental rotation and reaction time variables. Another important result was no significant difference in both mental rotation and reaction time variables between deaf male non-athletes and female non-athletes. As a result, it is suggested that doing sports improves both the mental rotation and reaction time of deaf male athletes.

Efficacy of the static isometric neck exercises and hold- relax (PNF) technique to relive cervicogenic headache among college students

Introduction: The word cervicogenic headache is defined as “referred pain perceived in any part of the head caused by primary nociceptive source in musculoskeletal tissues innervated by cervical nerves”. Symptoms is usually unilateral and does not change its side, it begins in neck and spread to head. Pain, tenderness, stiffness, decreased range of motion etc, are the most common symptoms. Pain can range from dull, deep ache to heavy pressure of severe intensity. In India, college students aged between 17 years – 23 years suggested to have prevalence of about 15.6 % of likely having cervicogenic headache. Materials and Methodology: Physiotherapy College students having cervicogeneic headache were included in the study. This is a study of assessment of pain, range of motion, cervical flexion rotation test among college students who have frequent cervicogenic headache. The study duration was about 3months including 80 sample size selected according to the inclusion and exclusion criteria. Results: Unpaired t test was done to compare different parameters in group A and group B. Paired t test was done in group A and in group B to compare pre and post intervention

Predictive factors of academic success in neuromusculoskeletal anatomy among doctor of physical therapy students.

Predictors of academic success in anatomy have been studied, but not in Doctor of Physical Therapy (DPT) students. The objectives of this study were to (1) explore predictors of academic success in a DPT anatomy course, (2) evaluate sex-based differences in the predictors of academic success and their influence on anatomy course grade, and (3) investigate the influence of the DPT anatomy course on visual-spatial ability. Forty-nine DPT students completed a demographic questionnaire, Learning and Study Strategies Inventory (LASSI), and Mental Rotations Test (MRT) before the ten-week anatomy course (MRT-1) and repeated the MRT at the end of the course (MRT-2). Anatomy course grade was determined based on quizzes and written and practical examinations. Multiple regression analysis showed significant associations between the predictor variables age (p=0.010) and the LASSI anxiety subscale (p=0.017), which measures anxiety coping, with the anatomy course grade. On the MRT-1, male DPT students attempted and correctly answered more questions than females (both, p < 0.0001). Female students had higher LASSI self-regulation and use of academic resources subscale scores (both, p < 0.05). In the 44 DPT students that completed the MRT-2, the number of correct and attempted responses increased following the anatomy course (p < 0.0001). Age and anxiety coping, but not sex, are predictors of anatomy course grades in DPT students. Mental rotations test scores improved following the anatomy course. The LASSI should be used in other cohorts to identify students with low anxiety subscale scores in order to provide targeted support.

Modulating Microglia/Macrophage Activation by CDNF Promotes Transplantation of Fetal Ventral Mesencephalic Graft Survival and Function in a Hemiparkinsonian Rat Model.

Parkinson’s disease (PD) is characterized by the loss of dopaminergic neurons in substantia nigra pars compacta, which leads to the motor control deficits. Recently, cell transplantation is a cutting-edge technique for the therapy of PD. Nevertheless, one key bottleneck to realizing such potential is allogenic immune reaction of tissue grafts by recipients. Cerebral dopamine neurotrophic factor (CDNF) was shown to possess immune-modulatory properties that benefit neurodegenerative diseases. We hypothesized that co-administration of CDNF with fetal ventral mesencephalic (VM) tissue can improve the success of VM replacement therapies by attenuating immune responses. Hemiparkinsonian rats were generated by injecting 6-hydroxydopamine (6-OHDA) into the right medial forebrain bundle of Sprague Dawley (SD) rats. The rats were then intrastriatally transplanted with VM tissue from rats, with/without CDNF administration. Recovery of dopaminergic function and survival of the grafts were evaluated using the apomorphine-induced rotation test and small-animal positron emission tomography (PET) coupled with [18F] DOPA or [18F] FE-PE2I, respectively. In addition, transplantation-related inflammatory response was determined by uptake of [18F] FEPPA in the grafted side of striatum. Immunohistochemistry (IHC) examination was used to determine the survival of the grated dopaminergic neurons in the striatum and to investigate immune-modulatory effects of CDNF. The modulation of inflammatory responses caused by CDNF might involve enhancing M2 subset polarization and increasing fractal dimensions of 6-OHDA-treated BV2 microglial cell line. Analysis of CDNF-induced changes to gene expressions of 6-OHDA-stimulated BV2 cells implies that these alternations of the biomarkers and microglial morphology are implicated in the upregulation of protein kinase B signaling as well as regulation of catalytic, transferase, and protein serine/threonine kinase activity. The effects of CDNF on 6-OHDA-induced alternation of the canonical pathway in BV2 microglial cells is highly associated with PI3K-mediated phagosome formation. Our results are the first to show that CDNF administration enhances the survival of the grafted dopaminergic neurons and improves functional recovery in PD animal model. Modulation of the polarization, morphological characteristics, and transcriptional profiles of 6-OHDA-stimualted microglia by CDNF may possess these properties in transplantation-based regenerative therapies.

The Effect of Shot-Peening Time on Tribological Behavior of AISI5160 Steel

The aim of this study is to investigate the tribological behavior of disks made of AISI5160 steel that were austempered at 288 °C for 120 min until the bainite microstructure was completely formed. Then shot peening was applied for 0 (not shot peened), 1, 2, 3, 4, or 5 min. Before tribotests, x-ray diffraction (XRD) was employed to measure the compressive residual stress. A rotary test rig was employed to run the tribotests, and scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) were employed to analyze the worn surfaces post tribotests. The compressive residual stress increased as the shot-peening time increased. Shot peening provided lower protection against wear than disk samples without shot peening. Wear debris increased during the tribotests on disk samples that had longer shot peening and led to more wear loss. This occurred because longer shot-peening time generated more cracks than shorter shot peening or no shot peening before tribotests. A limited amount of debris was found to protect the balls against wear; however, additional debris increased wear volume on the ball and led to plowing wear as well.

Should Diastatic Syndesmosis be Stabilized in Advanced Pronation-External Rotation Ankle Injuries? A Retrospective Cohort Comparison.

ObjectiveWith or without screw stabilization for diastatic syndesmosis in advanced pronation‐external rotation (PE) ankle injuries has not yet been well‐determined. Both techniques were retrospectively compared to investigate the superiority of either of the two.MethodsA retrospective cohort study was carried out. From January 1, 2008, to December 31, 2017, 81 consecutive adult patients (average, 42 years; range, 18–78 years; 44 men and 37 women) with advanced PE ankle injuries (stage 3 or 4 PE type) were treated. After malleolar fractures were internally stabilized with screws and plates, the syndesmotic stability was rechecked by external rotation and hook tests. The necessity of cortical screw insertion to stabilize diastatic syndesmosis was decided by the individual orthopaedic surgeon. Postoperatively, a short leg splint was used for 6 weeks. The syndesmotic screw was removed based on the surgeon's policy. The removal of internal fixation for malleolar fractures was required after 1 year. The outcomes of both approaches were compared clinically, and ankle function was compared using the American Orthopaedic Foot and Ankle Society (AOFAS) score. For statistical comparison, the chi‐square test was used for categorical data and the Mann–Whitney U test was used for numerical data.ResultsSeventy‐one patients (average, 40 years; range, 18–78 years; 40 men and 31 women) were followed for at least 1 year (87.7%; average, 2 years; range, 1–11 years). Group 1 (with syndesmotic stabilization) had 22 patients and Group 2 (without syndesmotic stabilization), 49 patients. The union rate in Group 1 patients was 100% (22/22), and in Group 2 patients, 91.8% (45/49; p = 0.17). One deep wound infection occurred in Group 1 patients and two in Group 2 patients. Syndesmosis re‐diastasis occurred in 13.6% (3/22) of Group 1 patients and 30.6% (15/49) of Group 2 patients (p = 0.13). One syndesmotic screw broke at 6 months. Satisfactory ankle function according to the AOFAS score was noted in 86.4% (19/22) of Group 1 patients and 65.3% (32/49) of Group 2 patients (p = 0.07).ConclusionInsertion of syndesmotic screws to promote ligament healing after internal fixation of malleolar fractures in advanced PE ankle injuries may be reasonable.

Performance Improvement Effect of Asphalt Binder Using Pyrolysis Carbon Black

The generation of waste tires is rapidly increasing. Waste tire pyrolysis is an alternative to waste tire recycling. The main substances extracted in the waste tire pyrolysis method include oil, carbon black, and iron. In this study, carbon black from the pyrolysis of waste tires was used to modify and improve the permanent deformation properties of the asphalt binder, and 0%, 5%, 10%, 15%, and 20% of pyrolysis carbon black by weight were mixed in raw asphalt, which is called AP-3 and AP-5. Laboratory tests, such as the softening point test, flash point test, rotational viscometer test, dynamic shear rheometer test, and bending beam rheometer test, were carried out. The use of pyrolysis carbon black increased the softening point and rotational viscosity at 135 °C. When using 15% PCB for AP-3 and 10% PCB for AP-5, the performance improvement effect of the resistance to permanent deformation was significant. The use of pyrolysis carbon black decreased fatigue at room temperature and improved the resistance of low-temperature cracking up to −12 °C but gave poor results at −18 °C.

The effect of onlay cortical fibula strut grafts on biomechanical features of Vancouver type B1 periprosthetic femoral fractures.

This study aimed to investigate biomechanically the effects of onlay fibula grafts on Vancouver Type B1 Periprosthetic Femoral Fractures (PPFs). Vancouver Type B1 PFF models were created in 25 fourth-generation synthetic femurs and fixed with locking plates using bicortical, unicortical screws, and cables. While no graft was used in group 1, onlay fibula grafts were placed anteriorly in group 2 and medially in group 3. In group 4, the cortical strut allograft was placed on the medial femoral cortex, and a locking compression plate (LCP) was applied to the lateral femoral cortex. In group 5, the strut allograft was placed over the anterior cortex of the femur and fixed with the same technique as in group 4. All models were then subjected to rotational and axial cyclical stiffness tests and load to failure to measure and compare the mechanical strengths of the constructs. The mean stiffness values of group 4 with medial allograft, before and after cyclical loading, were higher than all other groups, under both rotational and axial forces. The mean stiffness values of fibula autografts (groups 2 and 3) were similar to that of anterior allografts (group 5) in each test except that the mean initial axial stiffness of group 5 was higher than group 2. Failure loads were also not different between the groups. Although the rigidity of Vancouver type B1 periprosthetic femur fractures is highest if allografts are placed medially, fibula autografts can also provide similar fixation strengths to allografts if locking plates with unicortical and bicortical screws and cables are used.

Association between femoroacetabular impingement syndrome and limited lateral hip rotation in young athletes: A case-control study.

Purpose:Hip pain is very common in athletes. One of the main disorders causing hip pain is femoroacetabular impingement syndrome. This study aimed to identify a new etiological risk factor for femoroacetabular impingement in the hip.Methods:This case–control study included 88 young athletes, 34 with pains in the hip (supposedly with femoroacetabular impingement) and 54 controls. Femoroacetabular impingement was diagnosed with a flexion, adduction, internal, and rotation test and a particular type of hip pain during sports activities. The medial (internal) and lateral (external) hip ranges of rotation have been measured with an inclinometer. The data were analyzed using a t-test, the Wilcoxon test, the Mann–Whitney U test, and logistic regression.Results:There is a statistically significant difference in the external hip rotation range between the athletes with hip pain and controls. Logistic regression analysis showed that external hip range of motion is significantly associated with femoroacetabular impingement.Conclusion:Limited external hip range of motion was found to be significantly associated with the diagnosis of femoroacetabular impingement in young athletes. A biomechanical explanation of the hypothesis that limited external hip rotation can predict femoroacetabular impingement is given. Based on our results, the hip’s lateral range of motion screening can be advised within the regular screening of young athletes. Kinesiotherapeutic procedures for stretching the muscles of the medial hip rotors can be advised to prevent the lateral hip rotation restriction and lower the risk of femoroacetabular impingement in case the limited rotation is due to muscular restriction.Level of evidence:level III—case–control study.

The effect of chitosan nanoparticles on the rheo-viscoelastic properties and lipid digestibility of oil/vinegar mixtures (vinaigrettes)

The role of chitosan nanoparticles on the rheological behaviour, antioxidant properties and lipid digestibility of vinaigrettes was investigated in comparison with a protonated chitosan polymer. Nanoparticles were produced using different concentrations of tripolyphosphate (TPP) and acetic acid. The lower ionic concentrations were used to encapsulate a fish protein hydrolysate. Rotatory tests produced shear-thinning behaviour in the different nanoparticle suspensions. The vinaigrettes with addition of both chitosan and nanoparticles exhibited a stationary shear-thinning flow with viscoelastic characteristics of weak gels. The presence of chitosan nanoparticles in the emulsified oil phase produced a three-dimensional network with higher energy stability in the case of hydrolysate-loaded nanoparticles. Both chitosan and chitosan nanoparticles increased the radical scavenging capacity of vinaigrettes, but not the ferric ion reducing power. Addition of empty or hydrolysate-loaded nanoparticles reduced lipid digestion in vinaigrettes to a greater extent than chitosan (≈45% with nanoparticles; 33% with chitosan).

Return to play following nonsurgical management of superior labrum anterior-posterior tears: a systematic review

Superior labrum anterior-posterior (SLAP) tears are common shoulder injuries, especially in overhead athletes. Often, initial management of these injuries is nonsurgical with focused rehabilitation. The purpose of this review was to evaluate the outcomes of nonsurgical management of SLAP tears in athletes. A systematic review was performed for articles published before March 2021 using key search terms pertaining to clinical studies evaluating the nonsurgical treatment of SLAP tears in adult patients published in English-language literature. Abstracts and manuscripts were independently reviewed by 2 co-authors to determine eligibility. Return-to-play rate and return-to-prior-athletic-performance rate were determined by combining results across studies. Five articles met the inclusion criteria. There were 244 total athletes (162 elite or higher-level athletes). The mean ages ranged from 20.3 to 38.0 years. Type II SLAP tears were most common; baseball, softball, and weightlifting were the most common sports involved. The return-to-play rate was 53.7% in all athletes and 52.5% in elite or higher-level athletes. In athletes who were able to complete their nonoperative rehabilitation program, the return-to-play rate was 78% in all athletes and 76.6% in elite or higher-level athletes. The overall rate of return to prior performance was 42.6%, which increased to 72% for those athletes who were able to complete their rehabilitation. Patients who discontinued the rehabilitation protocol in favor of surgery had an average of 8 physical therapy sessions compared with 20 sessions for patients with successful nonoperative treatment. The timing of return to play was generally less than 6 months in studies that reported it. Patient-reported outcomes, including the American Shoulder and Elbow Surgeons score and visual analog scale, all improved significantly after nonsurgical treatment. Factors associated with failure of nonsurgical management included older age, participation in overhead sports (especially baseball pitchers), traumatic injury, positive compression rotation test, concomitant rotator cuff injury, longer baseball career, longer symptomatic period, and the presence of a Bennett spur. Overall, nonoperative treatment of SLAP tears in athletes can be successful, especially in the subset of patients who are able to complete their rehabilitation program before attempting a return to play. Although nonoperative treatment should be considered the first line of treatment for most SLAP tears, there are some factors that may be associated with failure of conservative treatment; therefore, further high level, prospective studies would be beneficial to identify those athletes most likely to respond favorably to nonoperative treatment.

Short-term effectiveness of high-load compared with low-load strengthening exercise on self-reported function in patients with hypermobile shoulders: a randomised controlled trial

ObjectivesTo investigate the short-term effectiveness of high-load versus low-load strengthening exercise on self-reported function in patients with hypermobility spectrum disorder (HSD) and shoulder symptoms.MethodsA superiority, parallel-group, randomised trial (balanced block...

Selective laser melting of WC-Co reinforced AISI 1045 steel composites: microstructure characterization and mechanical properties

Due to the limited wear resistance, AISI 1045 steel has limited applications in harsh environments, and the friction effect leads to premature scrapping. In order to improve the mechanical properties of AISI1045 steel, in this study, WC-Co particles reinforced AISI 1045 steel composites were produced by selective laser melting (SLM), and mainly focused on the influence of laser line energy density (LED) on the microstructure and mechanical properties in detail. The Vickers hardness test and rotational friction test were conducted to determine the Vickers hardness and friction resistance properties of composites. Results demonstrated that the SLM 500 J/m WC-Co/AISI 1045 steel composites possesses higher Vickers hardness and wear resistance compared to that of other samples owing to the finer grains and higher relative density. Herein, the wear mechanism and the binding interface of the SLM composites was also deeply discussed in this paper.

0056 Rest-Activity Rhythms (RARs) and Cognitive Functions in Early Post-menopausal Women

Abstract Introduction RAR disruptions are more common among individuals with dementia than healthy individuals. In healthy older women, RAR disruption predicted future diagnosis of Mild Cognitive Impairment (MCI). With no cure for Alzheimer’s Disease, it is crucial to identify modifiable risk-factors for early prevention of cognitive decline. Here we aim to determine whether RAR disruption was associated with cognitive status and cognitive performance in early post-menopausal women, thereby representing a modifiable risk factor for dementia. Methods The sample drawn from MsBrain study, included 229 cognitively unimpaired women and 42 women with MCI/dementia, based on score on Montreal Cognitive Assessment (MOCA) adjusted for age and race. Participants completed a 72-hour wrist actigraphy monitoring and neuropsychological assessment including: California Verbal Learning Test (CVLT), Letter Number Sequencing (LNS), Card Rotation Test, Symbol Digit Modalities Test (SDMT). Latent profile analysis (LPA) was performed using five nonparametric RAR variables (intra-daily variability (IV), inter-daily stability (IS), relative amplitude (RA), alpha and F-statistic). The association between RAR clusters and cognitive performance and the relationship between RAR clusters, cognitive status and race/ethnicity were assessed using linear regression models, controlling for age, race/ethnicity, education and body mass index (BMI); and using chi-square test respectively. Results LPA revealed three clusters: Robust with high F-Stat, RA and IS and low IV; Normal;Weak with low RA and high alpha. The proportion of subjects with MCI/dementia did not differ between clusters however there was a significant association between race and RAR clusters, X2 (2, N = 271)=14.18, p&amp;lt;0[P1] .001, with non-white women more likely than white women to belong in the Weak group (p &amp;lt; .01). In an adjusted analysis of healthy women, the Weak group performed worse than the Robust group in LNS control (p&amp;lt;.050 ). In the unadjusted model, the Weak group performed worse than Robust group in CVLT Total Learning and Long Delay Recall and SDMT (p=.0074, p=.011and p= .0041, respectively). Conclusion Non-white women had weaker RAR than their white counterparts. Weaker RARs related to poorer working memory as measured by LNS; and poorer verbal memory and processing speed, measured by CVLT and SDMT however these effects were largely influenced by covariates, particularly race/ethnicity and education. Support (If Any)

Sıçanlarda 6-hidroksidopamin modeli ile oluşturulan Parkinson hastalığında valproik asit tedavisinin dopaminerjik nöronal kayıp üzerindeki anti-apoptotik etkileri

Aim: Parkinson’s disease (PD) is characterized by the progressive loss of dopaminergic neurons resulting in deterioration of motor activity in patients. Currently, available therapies including Levodopa (L-DOPA) are more geared toward the treatment of symptoms. Therefore, developing effective neuroprotective therapies is needed. Valproic acid (VPA) has shown potent neuroprotective effects on dopamine (DA) neurons in various brain regions. The aim of this study is to investigate whether VPA attenuates the neuronal loss when co-treated with L-DOPA in a 6-hydroxydopamine (6-OHDA) induced PD model in rats.Methods: Male Wistar Albino rats received intranigral injection of 6-OHDA unilaterally. Twelve days later rats received either saline, L-DOPA, VPA, or L-DOPA+ VPA for 9 days. To determine whether rats had dopaminergic neuronal loss apomorphine-induced rotation test was used. Immunohistochemical analyses were performed in the Substantia Nigra pars compacta (SNpc) by measuring the tyrosine hydroxylase (TH) positive neurons and the apoptotic neurons.Results: 6-OHDA injection showed clinically impairment of the motor function with histologically significant damage to the dopaminergic neurons. VPA administration combined with L- DOPA protected neurons in SNpc by increasing the TH positive neurons and by decreasing the apoptotic neurons. L-DOPA given as a monotherapy, on the other hand, was ineffective on these parameters.Conclusion: Our experiments demonstrated that VPA had a neuroprotective effect when used with L-DOPA in the PD rat model.

Design, fabrication, and testing of CVI-SiC/SiC turbine blisk under different load spectrums at elevated temperature

Abstract In this article, design, fabrication, and testing of SiC/SiC turbine blisk with the fiber’s preform of Spider Web Structure (SWS) subjected to different load spectrums at elevated temperature are conducted. Micro-CT scans are conducted to show the fibers preform and defects inside the SWS-SiC/SiC turbine blisk. For 2D plain-woven SiC/SiC composite under monotonic tensile loading at an elevated temperature of T = 900°C in air atmosphere, the composite ultimate tensile strength is σ uts = 200 MPa with the fracture strain ε f = 0.36%. For SWS-SiC/SiC turbine blisk under the rotation testing, the first and second order natural frequency of the SWS-SiC/SiC turbine blisk are tested using the laser vibration meter. Relationships between the rotation speed, internal damage, and the natural frequency degradation of the SWS-SiC/SiC turbine blisk are established. Under the maximum rotation speed of n = 17,000 rpm at the exhaust temperature of T = 930°C, no damage occurred in the SWS-SiC/SiC turbine blisk. However, multiple coating spalling occurred due to the thermal-chemical coupling failure of the coating under flame impingement. The first natural frequency of the SWS-SiC/SiC turbine blisk decreases by 5% with the increase in the rotating speed from n max = 85,000 rpm to n max = 105,000 rpm, which indicates that there is an internal damage in the SWS-SiC/SiC turbine blisk, which leads to the decrease in the stiffness of the blisk.

Microstructural, Mechanical and Wear Properties of Al–1.3%Si Alloy as Compared to Hypo/Hyper–Eutectic Compositions in Al–Si Alloy System

The microstructure, mechanical properties, and wear behavior of three Al–Si alloys, namely: Al–1.3%Si, Al–1.5%Si and Al–13.5%Si were investigated. The specimens were examined by using an optical microscope to investigate the microstructural features of pin materials. Microhardness numbers and mechanical behavior parameters were determined by using a microhardness indenter and compression test, respectively. The dry sliding wear test was carried out using a pin-on-disc apparatus by varying the rotational speed (250, 350, and 450 rpm), normal load (5, 10 and 20 N) and test time (5, 10 and 15 min) at a constant sliding diameter of 300 mm. The surface roughness index (Ra) of the worn surfaces was determined by using a profilometer. The microstructure of Al–1.3%Si alloy was described as a fine eutectic colonizing in the FCC-Al phase matrix. Coarse eutectic dendrites surrounding the primary FCC-Al grains were observed in Al–1.5%Si alloy. The microstructure of Al–13.5%Si alloy showed a uniform layered structure of FCC-Al + Diamond Si eutectic. The average microhardness number was directly proportional to the Si concentration. Al–13.5%Si alloy with a high microhardness number (47.16 HV) showed excellent resistance to wear and exhibited a smoother surface at the end-of-wear test. The improved wear resistance in this case could be due to the presence of Diamond-Si hard phase in large quantities compared with other compositions. On the other hand, Al–1.5%Si alloy showed poorer resistance to wear because the mass loss action was dominated by a particle detachment mechanism. The response surfaces of the mass loss vs. speed, normal load and time showed increased mass loss when the three controlled parameters were increased. However, Pareto charts of the main effects of parametric interactions showed that the normal load was the main factor that must be considered when studying the tribological properties of Al–Si alloys.

Effect of PET Size, Content and Mixing Process on the Rheological Characteristics of Flexible Pavement

The performance of asphalt binder reinforced with waste plastic polyethylene terephthalate (PET) was investigated. Penetration, ductility, softening point, and rotational viscosity tests were conducted to check the performance of the PET-reinforced pavement. The rheological properties of the binder were determined using amplitude sweep and frequency sweep tests and performance grade (PG) measurements of aged and unaged specimens. PET size, mix mechanism, and mix temperature significantly influenced the physical properties of the AB and the penetration index (PI). The size and content of PET had pronounced effects on the PI and softening point than the blending temperature. Increasing the size of PET particles from 75 to 150 μm and the content from 0% to 10% of the bitumen resulted in the reduction of the penetration and ductility values from 96 to 85 mm and 100 to 78 cm, respectively, whereas the softening point increased from 46 to 56.6 °C. As a result, the PI value of the binder increased, which indicates that the temperature susceptibility was improved. The addition of 10% PET increased the viscosity of the baseline bitumen by threefold upto a temperature of 135 °C and dropped it by fourfold when the temperature was raised to 165 °C. Increasing the PET from 0% to 10% and the temperature from 21.1 to 54.4 °C increased the critical strain value (LVER) by 96%.