Abstract Additive manufacturing (AM) technology has experienced significant growth in recent years, opening new prospects across various sectors, from biomedicine to aerospace. Among these, the Fused ...Filament Fabrication (FFF) additive manufacturing technology, which deposits material layer by layer, enables the integration of piezoelectric material during the printing process, thereby allowing for the creation of sensors within thermoplastic components. Such sensors have the potential to monitor and detect various internal physical parameters within the component at locations inaccessible to traditional sensors. In this field, scientific research is continuously advancing, primarily aimed at developing sensors with high performance. In this context, the objective of this study is to assess the measurement properties, both static and dynamic, of sensors produced using this technology and to evaluate the influence on the static and dynamic behavior of the component caused by the incorporation of these sensors within the component itself.
To discuss the proper methods used to elicit the Hoffmann reflex (H-reflex) and to present different situations in which this tool can be used in sports medicine research.
We searched MEDLINE and ...SPORT Discus from 1960 to 2004 using the key words Hoffmann reflex, H-reflex, and methodology. The remaining citations were collected from references of similar papers.
Numerous authors have used the H-reflex as a tool to examine neurologic conditions. However, few have used the H-reflex to examine neuromuscular impairments after sport injuries. Several studies were available describing the appropriate methods to elicit the H-reflex and examining the reliability of this measurement in different muscles.
The H-reflex is a valuable tool to evaluate neurologic function in various populations. However, because of the sensitivity of this measurement to extraneous factors, care must be taken when eliciting the H-reflex. We discuss recommendations on how to elicit the H-reflex and how to appropriately present methods in a manuscript.
Nanoparticle albumin-bound (nab)-paclitaxel has better efficacy and practically eliminates the risk of hypersensitivity reactions associated with solvent-based paclitaxel. We studied weekly ...nab-paclitaxel and gemcitabine combination in an open-label one-stage, phase II trial in patients with previously untreated metastatic breast cancer (MBC). Nab-paclitaxel (125 mg/m2) and gemcitabine (1000 mg/m2) were administered on days 1 and 8 of a 21-day cycle until disease progression. Fifty patients were enrolled. Forty (80%) had visceral organ involvement and 30 (60%) had ≥ 3 sites of metastases. Four (8%) and 21 (42%) patients had complete and partial responses by Response Evaluation Criteria in Solid Tumors (RECIST) criteria. Median duration of response was 6.9 months 95% confidence interval (CI) 5.7, not reached, median progression-free survival (PFS) 7.9 months (95% CI 5.4–10 months), and median overall survival (OS) was not reached. PFS and OS at 6 months were 60% (95% CI 48% to 76%) and 92% (95% CI 85% to 100%), respectively. Therapy was well tolerated. Neutropenia was commonest toxicity (42% and 12% grades 3 and 4 neutropenia). Only one patient developed febrile neutropenia. Significant activity and favorable toxicity profile provides a basis for considering this regimen for further evaluation in phase III trials or in combination with biologic agents.
Previous research suggests more biomechanically demanding tasks (e.g., stair descent, hopping) magnify biomechanical asymmetries compared with walking after anterior cruciate ligament (ACL) ...reconstruction. However, it is unclear if modifying task‐specific constraints, like walking speed also elicits greater biomechanical asymmetries in this population. We examined the effects of manipulating walking speed on ground reaction force (GRF) asymmetries in individuals with ACL reconstruction and uninjured controls. Thirty individuals with ACL reconstruction (age = 20.6 ± 5.4 years, body mass index BMI = 23.9 ± 3.3 kg/m2) and 15 controls (age = 23.1 ± 4.5 years, BMI = 23.6 ± 2.7 kg/m2) were tested on an instrumented treadmill at three speeds (100%, 120%, and 80% self‐selected speed). Bilateral vertical and posterior‐anterior GRFs were recorded at each speed. GRF asymmetries were calculated by subtracting the uninjured from the injured limb at each percent of stance. Statistical parametric mapping was used to evaluate the effects of speed on GRF asymmetries across stance. We found vertical and posterior GRF asymmetries were exacerbated at faster speeds and reduced at slower speeds in ACL individuals but not controls (p < .05). No differences in anterior GRF asymmetries were observed between speeds in either group (p > .05). Our results suggest increasing walking speed magnifies GRF asymmetries in individuals with ACL reconstruction. Statement of Clinical Significance: Evaluating both preferred and fast walking speeds may aid in characterizing biomechanical asymmetries in individuals with ACL reconstruction which may be valuable in earlier rehabilitative time points when more difficult tasks like hopping and running are not feasible.
In this study, the effects of temporal changes in unanticipated (UN) prelanding stimuli on lower limb biomechanics and the impact of sex and limb dominance on these variables during single-leg ...landings were determined. It was hypothesised that reductions in the time of prelanding UN stimuli, female sex, and the non-dominant limb would significantly increase high-risk landing biomechanics during UN jump landings.
26 (13 men and 13 women) had initial contact (IC) and peak stance (0-50%) phase (PS) lower limb joint kinematics and kinetics quantified during anticipated (AN) and UN single-leg (left and right) landings. Postlanding jump direction was governed via one of two randomly ordered light stimuli, presented either before initiation of the jump (AN), or 600 ms (UN1), 500 ms (UN2) or 400 ms (UN3) immediately before ground contact.
Statistically significant (p<0.05) differences in IC hip posture and PS hip and knee internal rotation moments occurred in UN compared with AN landings. Differences were not observed, however, among UN conditions for any biomechanical comparisons. Significant (p<0.05) differences in specific IC and PS hip and knee postures and loads occurred between sexes and limbs. Neither of these factors, however, influenced movement condition effects.
UN landings induce modifications in landing biomechanics that may increase anterior cruciate ligament injury risk in both men and women. These modifications, however, do not appear overly sensitive to the timing of the UN stimulus, at least within a temporal range affording a successful movement response. Expanding UN training to include even shorter stimulus-response times may promote the additional central control adaptations necessary to manoeuvre safely within the random sports setting.
The stronger anatomo-functional connections of the supplementary motor area (SMA), as compared with premotor area (PM), with regions of the limbic system, suggest that SMA could play a role in the ...control of movements triggered by visual stimuli with emotional content. We addressed this issue by analysing the modifications of the excitability of the primary motor area (M1) in a group of seven healthy subjects, studied with transcranial magnetic stimulation (TMS), after conditioning TMS of SMA, during emotional and non-emotional visually cued movements. Conditioning TMS of the PM or of contralateral primary motor cortex (cM1) were tested as control conditions. Single-pulse TMS over the left M1 was randomly intermingled with paired TMS, in which a conditioning stimulation of the left SMA, left PM or right M1 preceded test stimulation over the left M1. The subjects carried out movements in response to computerised visual cues (neutral pictures and pictures with negative emotional content). The amplitudes of motor-evoked potentials (MEPs) recorded from the right first dorsal interosseous muscle after paired TMS were measured and compared with those obtained after single-pulse TMS of the left M1 under the various experimental conditions. Conditioning TMS of the SMA in the paired-pulse paradigm selectively enhanced MEP amplitudes in the visual-emotional triggered movement condition, compared with single-pulse TMS of M1 alone or with paired TMS during presentation of neutral visual cues. On the other hand, conditioning TMS of the PM or cM1 did not differentially influence MEP amplitudes under visual-emotional triggered movement conditions. This pattern of effects was related to the intensity of the conditioning TMS over the SMA, being most evident with intensities ranging from 110% to 80% of motor threshold. These results suggest that the SMA in humans could interface the limbic and the motor systems in the transformation of emotional experiences into motor actions.
Background: Arthrogenic quadriceps muscle inhibition accompanies knee joint effusion and impedes rehabilitation after knee joint injury.
Hypothesis: We hypothesized that an experimentally induced ...knee joint effusion would cause arthrogenic quadriceps muscle inhibition and
lead to increased ground reaction forces, as well as sagittal plane knee angles and moments, during a single-legged drop landing.
Study Design: Controlled laboratory study.
Methods: Nine subjects (4 women and 5 men) underwent 4 conditions (no effusion, lidocaine injection, âlowâ effusion 30 mL, and âhighâ
effusion 60 mL) and then performed a single-legged drop landing. Lower extremity muscle activity, peak sagittal plane knee
flexion angles, net sagittal plane knee moments, and peak ground reaction forces were measured.
Results: Vastus medialis and lateralis activity were decreased during the low and high effusion conditions ( P < .05) . However, increases in peak ground reaction forces and decreases in peak knee flexion angle and net knee extension moments
occurred only during the high effusion condition ( P < .05) .
Conclusions: Knee joint effusion induced quadriceps inhibition and altered knee joint mechanics during a landing task. Subjects landed
with larger ground reaction forces and in greater knee extension, thereby suggesting that more force will be transferred to
the knee joint and its passive restraints when quadriceps inhibition is present.
Clinical Relevance: Knee joint effusion results in arthrogenic quadriceps muscle inhibition, increasing loading about the knee that may potentially
increase the risk of future knee joint trauma or degeneration.
Keywords:
muscle activation
swelling
knee
injury
Itaconate, the product of the decarboxylation of cis-aconitate, regulates numerous biological processes. We and others have revealed itaconate as a regulator of fatty acid β-oxidation, generation of ...mitochondrial reactive oxygen species and the metabolic interplay between resident macrophages and tumors. In the present study, we show that itaconic acid is upregulated in human non-alcoholic steatohepatitis and a mouse model of non-alcoholic fatty liver disease. Male mice deficient in the gene responsible for itaconate production (immunoresponsive gene (Irg)-1) have exacerbated lipid accumulation in the liver, glucose and insulin intolerance and mesenteric fat deposition. Treatment of mice with the itaconate derivative, 4-octyl itaconate, reverses dyslipidemia associated with high-fat diet feeding. Mechanistically, itaconate treatment of primary hepatocytes reduces lipid accumulation and increases their oxidative phosphorylation in a manner dependent upon fatty acid oxidation. We propose a model whereby macrophage-derived itaconate acts in trans upon hepatocytes to modulate the liver's ability to metabolize fatty acids.
•We analysed the influence of flexible component dynamics in random fatigue.•The relation between the Gaussianity or not of loads and outputs was analysed.•The influence of loads stationarity on ...outputs non-Gaussianity was showed.•The activity was faced to simple flexible body characterized by bi-modal behaviour.
Even if in fatigue application it is common to assume stationary and Gaussian excitation, the impact of non-Gaussian and non-stationary loadings on the service life of a mechanical component is known. Non-Gaussian and non-stationary excitations are generally observed in several industrial applications (i.e. automotive, aeronautical, etc.) and for this, the assessment of the effect of such loads results necessary. From this assumption, the activity herein presented starts from experimental results, previously obtained, that analysed the influence of non-Gaussianity (generally evaluated by kurtosis) and of non-stationarity of inputs on the fatigue life of an Y-shaped specimen. In the present paper the finite element model of the sample and its full validation obtained by numerical/experimental comparison is presented. Moreover, due to the relevant effect of the system’s dynamics on the stress/strain response previously observed, a wider assessment of non-Gaussianity and non-stationarity influence on the fatigue life has been numerically analysed together with the influence of the multi modal behaviour of the component by adopting an excitation frequency range that excites two modes of the model.
Background Functional ankle instability (FAI) may be prevalent in as many as 40% of patients after acute lateral ankle sprain. Altered
afference resulting from damaged mechanoreceptors after an ankle ...sprain may lead to reflex inhibition of surrounding joint
musculature. This activation deficit, referred to as arthrogenic muscle inhibition (AMI), may be the underlying cause of FAI.
Incomplete activation could prevent adequate control of the ankle joint, leading to repeated episodes of instability.
Hypothesis Arthrogenic muscle inhibition is present in the peroneal musculature of functionally unstable ankles and is related to dynamic
peroneal muscle activity.
Study Design Cross-sectional study; Level of evidence, 3.
Methods Twenty-one (18 female, 3 male) patients with unilateral FAI and 21 (18 female, 3 male) uninjured, matched controls participated
in this study. Peroneal maximum H-reflexes and M-waves were recorded bilaterally to establish the presence or absence of AMI,
while electromyography (EMG) recorded as patients underwent a sudden ankle inversion perturbation during walking was used
to quantify dynamic activation. The H:M ratio and average EMG amplitudes were calculated and used in data analyses. Two-way
analyses of variance were used to compare limbs and groups. A regression analysis was conducted to examine the association
between the H:M ratio and the EMG amplitudes.
Results The FAI patients had larger peroneal H:M ratios in their nonpathological ankle (0.399 ± 0.185) than in their pathological
ankle (0.323 ± 0.161) ( P = .036), while no differences were noted between the ankles of the controls (0.442 ± 0.176 and 0.425 ± 0.180). The FAI patients
also exhibited lower EMG after inversion perturbation in their pathological ankle (1.7 ± 1.3) than in their uninjured ankle
(EMG, 3.3 ± 3.1) ( P < .001), while no differences between legs were noted for controls ( P > .05). No significant relationship was found between the peroneal H:M ratio and peroneal EMG ( P > .05).
Conclusion Arthrogenic muscle inhibition is present in the peroneal musculature of persons with FAI but is not related to dynamic muscle
activation as measured by peroneal EMG amplitude. Reversing AMI may not assist in protecting the ankle from further episodes
of instability; however dynamic muscle activation (as measured by peroneal EMG amplitude) should be restored to maximize ankle
stabilization. Dynamic peroneal activity is impaired in functionally unstable ankles, which may contribute to recurrent joint
instability and may leave the ankle vulnerable to injurious loads.
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