Retention of gait stability improvements over 1.5 years in older adults:effects of perturbation exposure and triceps surae neuromuscular exercise

The plantarflexors play a crucial role in recovery from sudden disturbances to gait. The objective of this study was to investigate whether medium (months)- or long(years)-term exercise-induced enhancement of triceps surae (TS) neuromuscular capacities affects older adults' ability to retain improvements in reactive gait stability during perturbed walking acquired from perturbation training sessions. Thirty-four adult women (65 +/- 7 yr) were recruited to a perturbation training group (n = 13) or a group that additionally completed 14 wk of TS neuromuscular exercise (n = 21), 12 of whom continued with the exercise for 1.5 yr. The margin of stability (MoS) was analyzed at touchdown of the perturbed step and the first recovery step following eight separate unexpected trip perturbations during treadmill walking. TS muscle-tendon unit mechanical properties and motor skill performance were assessed with ultrasonography and dynamometry. Two perturbation training sessions (baseline and after 14 wk) caused an improvement in the reactive gait stability to the perturbations (increased MoS) in both groups. The perturbation training group retained the reactive gait stability improvements acquired over 14 wk and over 1.5 yr. with a minor decay over time. Despite the improvements in TS capacities in the additional exercise group. no benefits for the reactive gait stability following perturbations were identified. Therefore, older adults' neuromotor system shows rapid plasticity to repeated unexpected perturbations and an ability to retain these adaptations in reactive gait stability over a long time period, but an additional exercise-related enhancement of TS capacities seems not to further improve these effects. NEW & NOTEWORTHY Older adults' neuromotor system shows rapid plasticity to repeated exposure to unexpected perturbations to gait and an ability to retain the majority of these adaptations in reactive recovery responses over a prolonged time period of 1.5 yr. However, an additional exercise-related enhancement of TS neuromuscular capacities is not necessarily transferred to the recovery behavior during unexpected perturbations to gait in older adults

Effect Of Triceps Surae Muscle-Tendon Unit Mechanical Properties On Gait Stability And Adaptability In Older Female Adults

INTRODUCTION Ageing induces a gradual degradation in the human neuro-motor system resulting in decreased mobility and locomotor performance (Beijersbergen et al., 2013). Moreover, inadequate recovery responses following tripping have been associated with age-related deteriorations in ankle plantar flexion moment output (magnitude and rate) in the push-off phase (Pijnappels et al., 2004). Therefore, the objective of this study was (1) to examine if gait stability and adaptability during perturbed walking is associated with TS muscle strength and Achilles tendon (AT) stiffness in older female adults, and (2) to determine whether elderly with different TS muscle strength capacities show an altered dynamic stability control during perturbed walking, and (3) whether gait plasticity is preserved in old age. METHODS Thirty-four older female adults (65±7yrs) experienced unexpected trip perturbations to the swing phase of the right leg while walking on a treadmill (Süptitz et al., 2013). Using a motion capture system (VICON; Oxford, UK) the margin of stability (MoS) and base of support (BoS) were assessed at touchdown (TD) of the perturbed leg and at each following six recovery steps. In order to examine the reactive adaptation potential, the MoS at TD of the perturbed leg was examined in eight unexpected perturbation trials. In an additional session, TS muscle strength and AT stiffness were determined using simultaneous ultrasonography and dynamometry. Pearson correlations were used to inspect the relationship between TS MTU mechanical properties and dynamic stability parameters (both MoS and BoS) of the recovery steps in first perturbation trial. A median split was implemented to classify the subjects into two groups based on their TS muscle strength (strong: n = 16; weak: n = 18). RESULTS The strong group had about 42% higher voluntary isometric plantarflexion moments and 33% higher AT stiffness than the weak group (138±22Nm vs. 97±10Nm; 588±156Nmm-1 vs. 441±129Nmm-1; p<0.01). The gait perturbation reduced the MoS at TD of the perturbed leg (-0.10±0.08m) compared to baseline unperturbed walking, indicating instability. The strong group needed three recovery steps to return to MoS baseline and the weak group was unable to return to baseline level within the analysed six recovery steps. Significant correlations between both TS muscle strength and AT stiffness, and MoS and BoS at TD of the first recovery step were found (0.41<r<0.68; p<0.05). After eight gait perturbations, both groups were able to adapt their reactive response to the perturbation (increasing MoS at TD), with no between-group differences. DISCUSSION The current data suggest that TS muscle strength and AT stiffness partly limit dynamic gait stability control after an unexpected perturbation during walking in older female adults. Recovery stepping behaviour seems to be less effective in weaker older adults, which is explained mainly by the reduced ability to effectively increase the BoS after perturbations. However, independent of TS MTU mechanical properties, older adults seem to be able to improve their reactive response. CONCLUSION TS MTU mechanical properties partly limit dynamic stability during perturbed walking in older adults, but they preserve their gait plasticity independent of their TS muscle strength. Thus, in order to reduce falls risk, older adults may benefit from interventions increasing TS muscle strength and tendon stiffness, and by improving reactive recovery responses via repeated gait perturbations. REFERENCES Beijersbergen et al., (2013). Ageing Res Rev. 12, 618-27. doi:10.1016/j.arr.2013.03.001 Pijnappels et al., (2004). J Biomech. 37, 1811-18. doi:10.1016/j.jbiomech.2004.02.038 Süptitz et al., (2013). Hum Mov Sci 32, 1404-14. doi:10.1016/j.humov.2013.07.00

Разработка алгоритма для выполнения операции обратного проецирования

High Power Pulsed Magnetron Sputtering (HPPMS) techniques jointly with the deposition of a graded Cr/CrN-nanointerlayer on cutting inserts can increase the film adhesion and consequently the tool life. These improvements depend on the roughness of the employed cemented carbide substrates. The investigations described in the present paper intend to explain the effect of Cr/CrN-interlayer thickness and substrate roughness on the coating adhesion and cutting performance. To attain various roughnesses, the applied cemented carbide inserts were superficially treated. These treatments were grinding at a medium roughness level, or grinding with subsequent polishing for enhancing the surface integrity and finally, in all cases, micro-blasting by fine Al2O3 grains. After Ar-ion etching, graded Cr/CrN adhesive layers with different thicknesses were deposited by HPPMS technology on the variously pretreated substrates. Subsequently, an approximately 3m thick (Ti,Al)N film was depos ited by HPPMS PVD on all used inserts. Rockwell C indentations and inclined impact tests were performed to assess qualitatively and quantitatively the films' adhesion. The cutting performance of the coated tools was investigated in milling of 42CrMo4 QT. FEM supported calculations of the developed stresses during the material removal process contributed in explaining the obtained tool wear results. In these calculations, the adhesion, dependent on the substrate roughness characteristics and on the adhesive interlayer thickness, was taken into account. The results revealed that the effectiveness of HPPMS adhesive graded Cr/CrN-nanointerlayer strongly depends on the substrate surface integrity and on the interlayer thickness. Thus, the film adhesion and consequently the cutting performance can be significantly improved if the interlayer thickness is adapted to the substrate roughness

Small primary adenocarcinoma in adenomyosis with nodal metastasis: a case report

<p>Abstract</p> <p>Background</p> <p>Malignant transformation of adenomyosis is a very rare event. Only about 30 cases of this occurrence have been documented till now.</p> <p>Case presentation</p> <p>The patient was a 57-year-old woman with a slightly enlarged uterus, who underwent total hysterectomy and unilateral adnexectomy. On gross inspection, the uterine wall displayed a single nodule measuring 5 cm and several small gelatinous lesions. Microscopic examination revealed a common leiomyoma and multiple adenomyotic foci. A few of these glands were transformed into a moderately differentiated adenocarcinoma. The endometrium was completely examined and tumor free. The carcinoma was, therefore, considered to be an endometrioid adenocarcinoma arising from adenomyosis. Four months later, an ultrasound scan revealed enlarged pelvic lymph nodes: a cytological diagnosis of metastatic adenocarcinoma was made.</p> <p>Immunohistochemical studies showed an enhanced positivity of the tumor site together with the neighbouring adenomyotic foci for estrogen receptors, aromatase, p53 and COX-2 expression when compared to the distant adenomyotic glands and the endometrium. We therefore postulate that the neoplastic transformation of adenomyosis implies an early carcinogenic event involving p53 and COX-2; further tumor growth is sustained by an autocrine-paracrine loop, based on a modulation of hormone receptors as well as aromatase and COX-2 local expression.</p> <p>Conclusion</p> <p>Adenocarcinoma in adenomyosis may be affected by local hormonal influence and, despite its small size, may metastasize.</p

Is adenomyosis the neglected phenotype of an endomyometrial dysfunction syndrome?

Since the dissociation between adenomyoma and endometriosis in the 1920s and the laparoscopic progress in the diagnosis and surgery of endometriosis, the literature has been greatly focused on the disease endometriosis. The study of adenomyosis, on the other hand, has been neglected as the diagnosis remained based on hysterectomy specimens. However, since the introduction of magnetic resonance and sonographic imaging techniques in the 1980s, the myometrial junctional zone has been identified as a third uterine zone and interest in adenomyosis was renewed. This has also been the start for the interest in the role of the myometrial junctional zone dysfunction and adenomyosis in reproductive and obstetrical disorders

Physical fitness, fatigue, and quality of life after liver transplantation

Fatigue is often experienced after liver transplantation. The aims of this cross-sectional study were to assess physical fitness (cardiorespiratory fitness, neuromuscular fitness, body composition) in liver transplant recipients and to explore whether physical fitness is related to severity of fatigue. In addition, we explored the relationship between physical fitness and health-related quality of life. Included were 18 patients 1–5 years after transplantation (aged 48.0 ± 11.8 years) with varying severity of fatigue. Peak oxygen uptake during cycle ergometry, 6-min walk distance, isokinetic muscle strength of the knee extensors, body mass index, waist circumference, skinfold thickness, severity of fatigue, and health-related quality of life were measured. Cardiorespiratory fitness in the liver transplant recipients was on average 16–34% lower than normative values (P ≤ 0.05). Furthermore, the prevalence of obesity seemed to be higher than in the general population (17 vs. 10%). We found no deficit in neuromuscular fitness. Cardiorespiratory fitness was the only fitness component that was related with severity of fatigue (rs = −0.61 to rs = -0.50, P ≤ 0.05). Particularly cardiorespiratory fitness was related with several aspects of health-related quality of life (rs = 0.48 to rs = 0.70, P ≤ 0.05). Results of our study imply that cardiorespiratory fitness and body composition are impaired in liver transplant recipients and that fitness is related with severity of fatigue (only cardiorespiratory fitness) and quality of life (particularly cardiorespiratory fitness) in this group. These findings have implications for the development of rehabilitation programs for liver transplant recipients

Kinder und Jugendliche in der Coronavirus-Pandemie: psychosoziale und edukative Herausforderungen und Chancen : 8. Ad-hoc-Stellungsnahme - 21. Juni 2021

Die Coronavirus-Pandemie hat für Kinder und Jugendliche vielfältige Auswirkungen auf deren Bildung, soziale Interaktion, sozioemotionale Entwicklung, körperliche Aktivität sowie auf das psychische Wohlbefinden. Viele Betroffene werden in der Lage sein, die Auswirkungen zu überwinden. Manche dagegen werden mittel- und wahrscheinlich auch langfristig von den erlittenen Defiziten begleitet. Um diesen zu begegnen, empfiehlt die Nationale Akademie der Wissenschaften Leopoldina in der Ad-hoc-Stellungnahme „Kinder und Jugendliche in der Coronavirus-Pandemie: psychosoziale und edukative Herausforderungen und Chancen“ den Auf- und Ausbau von Unterstützungs- und Bildungsstrukturen. Diese sollten die derzeit bestehenden Ungleichheiten in Bildungs- und Entwicklungschancen nachhaltig adressieren und nicht nur pandemiebedingte Nachteile ausgleichen, sondern die Situation im Vergleich zum Status Quo vor der Pandemie verbessern