scholarly journals Determining the Delay Time of the Muscles Around the Knee Joint in Response to Rotational Perturbation From Support Surface

2021 ◽  
Author(s):  
Fatemeh Ghasemi Dehcheshmeh ◽  
Ali Amiri ◽  
Nader Maroufi ◽  
Aliashraf Jamshidi ◽  
Shohreh Jalaei
Keyword(s):  
Reaction Time ◽  
Knee Joint ◽  
Delay Time ◽  
External Rotation ◽  
Support Surface ◽  
Rotational Perturbation ◽  
Knee Position ◽  
The Right ◽  
Short Time ◽  
Perturbation Direction

Introduction: Knee joint injuries usually occur in a short time, so analyzing the mechanism and process of this short time can be helpful to prevent similar injuries. This study aimed to determine and compare the reaction time of knee muscles and investigate the effect of  knee position and perturbation direction on the reaction time of knee muscles in response to horizontal rotational perturbation applied to lower leg from support surface area. Materials and Methods: A total of 30 healthy women volunteers were received ±35 degrees of horizontal rotational perturbation and speed of 120 degrees per second from the sole while standing on the right leg in four conditions (external versus internal rotation of surface while the knee was in both extension and flexion position). Electromyography of knee muscles (vastus medialis and lateralis, medial and lateral hamstring and medial and lateral gastrocnemius) was measured to study the reaction time. Results: The reaction time of knee muscles during the perturbation was relatively long in this study (124 to 151 ms). It seems that muscles are recruited simultaneously in most conditions except in external rotation perturbation, with extension knee that the internal gastrocnemius muscle had significantly less delay time than the internal hamstring (P<0.05) and external quadriceps (P<0.05). The results show that most of these muscles do not react selectively and dependently on perturbation direction and knee position in response to horizontal rotational perturbation. Conclusion: In this study, little difference was seen in the reaction time of most knee muscles in all conditions. Thus in response to this type of perturbation, the knee muscles showed co-contraction.

Legal Update: North Dakota Supreme Court: Third Edition of Guides is “Most Current”

1999 ◽  
Vol 4 (1) ◽  
pp. 6-7
Author(s):  
James J. Mangraviti
Keyword(s):  
Internal Rotation ◽  
External Rotation ◽  
Measurement Techniques ◽  
Fourth Edition ◽  
Hip Motion ◽  
The Difference ◽  
The Right ◽  
Hip Flexion ◽  
Hip Rotation ◽  
Hip Extension

Abstract The accurate measurement of hip motion is critical when one rates impairments of this joint, makes an initial diagnosis, assesses progression over time, and evaluates treatment outcome. The hip permits all motions typical of a ball-and-socket joint. The hip sacrifices some motion but gains stability and strength. Figures 52 to 54 in AMA Guides to the Evaluation of Permanent Impairment (AMA Guides), Fourth Edition, illustrate techniques for measuring hip flexion, loss of extension, abduction, adduction, and external and internal rotation. Figure 53 in the AMA Guides, Fourth Edition, illustrates neutral, abducted, and adducted positions of the hip and proper alignment of the goniometer arms, and Figure 52 illustrates use of a goniometer to measure flexion of the right hip. In terms of impairment rating, hip extension (at least any beyond neutral) is irrelevant, and the AMA Guides contains no figures describing its measurement. Figure 54, Measuring Internal and External Hip Rotation, demonstrates proper positioning and measurement techniques for rotary movements of this joint. The difference between measured and actual hip rotation probably is minimal and is irrelevant for impairment rating. The normal internal rotation varies from 30° to 40°, and the external rotation ranges from 40° to 60°.

Força dos Músculos Rotadores do Ombro em Indivíduos Saudáveis/ Rotator Cuff Muscle Strength in Healthy Individuals

1970 ◽  
Vol 1 (1) ◽  
pp. 78-82
Author(s):  
Paulo José Oliveira Cortez ◽  
José Elias Tomazini ◽  
Mauro Gonçalves
Keyword(s):  
Rotator Cuff ◽  
Muscle Strength ◽  
Internal Rotation ◽  
Upper Limb ◽  
Statistical Difference ◽  
External Rotation ◽  
Healthy Individuals ◽  
Average Strength ◽  
Strength Tests ◽  
The Right

Introdução: A diminuição da capacidade de exercer esforços por parte dos músculos rotadores pode criar uma variedade de problemas. O conhecimento preciso do nível de força muscular de um indivíduo é importante, tanto para a avaliação da capacidade funcional ocupacional, como para uma apropriada prescrição de exercícios atléticos e de reabilitação. Percebe-se escassez de informação sobre as articulações do ombro, bem como os fatores envolvidos na força muscular dessa região. O objetivo deste estudo foi comparar a força gerada pelos músculos do manguito rotador entre o membro superior direito e o membro superior esquerdo em indivíduos saudáveis. Métodos: Participaram do estudo 22 sujeitos do sexo masculino, com idade de 18 e 19 anos, militares, saudáveis e sem história clínica de patologia ortopédica ou qualquer tipo de lesão no sistema musculoesquelético. Foram aplicados dois testes de força: Rotação Interna e Rotação Externa. Resultado : A força média de rotação interna no membro superior direito (MSD) foi maior que a força média de rotação interna no membro superior esquerdo (MSE) (p=0,723) e a força de rotação externa no MSD foi menor que a força média de rotação externa no MSE (p=0,788). Não houve diferença estatística na comparação dos valores de força de todos os testes de força isométrica. Conclusão: Para amostra estudada e metodologia utilizada na avaliação da força muscular, não houve diferença estatística na comparação da força gerada pelos músculos do manguito rotador do membro superior direito e do membro superior esquerdo.Rotator Cuff Muscle Strength in Healthy Individuals Introduction: Decreased ability to exert efforts by the rotator muscles can create a variety of problems. The precise knowledge of the level of muscular strength of an individual is important for both the functional capacity evaluation for occupational as an appropriate exercise prescription and rehabilitation of athletic. It is perceived scarcity of information on the shoulder joints as well as factors involved in muscle strength in this region. Objective: Develop a device for measuring the strength generated by the muscles of the upper limbs and the verification of efficiency and adaptability of this device through a comparative study of muscle strength in healthy subjects. Methods: The study included 22 male subjects, aged 18 and 19 years, military personnel, body mass between 57.7 and 93 kg (71.8 ± 9.45 kg) and height between 1.67 and 1.90 m (1.75 ± 0.06 m), healthy and without a history of orthopaedic disease or any kind of damage to the musculoskeletal system. Three strength tests were applied: Internal Rotation and External Rotation. For each type of effort three maximum voluntary contractions were required for 10 seconds, with an interval of 30 seconds between each contraction.  Results: Internal rotation in the right upper limb (RUL) was higher than the average strength of internal rotation in the left upper limb (LUL) (p = 0, 723) and the external rotation strength in RUL was lower than the average strength of external rotation in the LUL (p=0,788).  No statistical difference in comparing the strength values of all isometric strength tests. Conclusion: For sample and methodology used to assess muscle strength, there was no statistical difference in comparing the force generated by the muscles of the rotator cuff of the right and left upper limb.

scholarly journals Neuro-Inspired Computing with Spin-VCSELs

2021 ◽  
Vol 11 (9) ◽  
pp. 4232
Author(s):  
Krishan Harkhoe ◽  
Guy Verschaffelt ◽  
Guy Van der Sande
Keyword(s):  
Processing Speed ◽  
Delay Time ◽  
High Speed ◽  
State Of The Art ◽  
Polarization Modulation ◽  
Time Interval ◽  
Computing Technique ◽  
High Modulation ◽  
Short Time ◽  
Modulation Speed

Delay-based reservoir computing (RC), a neuromorphic computing technique, has gathered lots of interest, as it promises compact and high-speed RC implementations. To further boost the computing speeds, we introduce and study an RC setup based on spin-VCSELs, thereby exploiting the high polarization modulation speed inherent to these lasers. Based on numerical simulations, we benchmarked this setup against state-of-the-art delay-based RC systems and its parameter space was analyzed for optimal performance. The high modulation speed enabled us to have more virtual nodes in a shorter time interval. However, we found that at these short time scales, the delay time and feedback rate heavily influence the nonlinear dynamics. Therefore, and contrary to other laser-based RC systems, the delay time has to be optimized in order to obtain good RC performances. We achieved state-of-the-art performances on a benchmark timeseries prediction task. This spin-VCSEL-based RC system shows a ten-fold improvement in processing speed, which can further be enhanced in a straightforward way by increasing the birefringence of the VCSEL chip.

scholarly journals Platypnoea–orthodeoxia syndrome induced by short-term weight loss: a case series

2020 ◽  
Author(s):  
Yudai Tamura ◽  
Tomohiro Sakamoto
Keyword(s):  
Weight Loss ◽  
Septal Defect ◽  
Case Series ◽  
Transoesophageal Echocardiography ◽  
Sitting Position ◽  
Short Time Period ◽  
Time Period ◽  
Uncommon Condition ◽  
The Right ◽  
Short Time

Abstract Background Platypnoea–orthodeoxia syndrome (POS) is an uncommon condition characterized by dyspnoea and arterial desaturation in the standing or sitting position that improves in the supine position. Case summary We report two cases of POS caused by an atrial septal defect (ASD) and a patent foramen ovale (PFO). Both cases reported a recent decrease in body weight of more than 10 kg in a short time period. Transoesophageal echocardiography (TOE) with agitated saline bubble study revealed and a large amount of contrast bubble through the ASD (Patient 1) or the PFO (Patient 2) from the right atrium to the left atrium in the sitting position. Both patients were diagnosed by the finding of positional dyspnoea and the results of TOE using agitated saline bubble contrast. Discussion Taken together, their presentations suggest that weight loss in a short time period could be a pathogenic factor for POS.

scholarly journals Lateralization of attention in adults with ADHD: Evidence of pseudoneglect

2020 ◽  
Vol 63 (1) ◽  
Author(s):  
Bartosz Helfer ◽  
Stefanos Maltezos ◽  
Elizabeth Liddle ◽  
Jonna Kuntsi ◽  
Philip Asherson
Keyword(s):  
Reaction Time ◽  
Visual Field ◽  
Reaction Times ◽  
Study Participant ◽  
Reaction Time Task ◽  
Right Visual Field ◽  
Time Variability ◽  
Incentive Condition ◽  
Reaction Time Variability ◽  
The Right

Abstract Background. We investigated whether adults with attention-deficit/hyperactivity disorder (ADHD) show pseudoneglect—preferential allocation of attention to the left visual field (LVF) and a resulting slowing of mean reaction times (MRTs) in the right visual field (RVF), characteristic of neurotypical (NT) individuals —and whether lateralization of attention is modulated by presentation speed and incentives. Method. Fast Task, a four-choice reaction-time task where stimuli were presented in LVF or RVF, was used to investigate differences in MRT and reaction time variability (RTV) in adults with ADHD (n = 43) and NT adults (n = 46) between a slow/no-incentive and fast/incentive condition. In the lateralization analyses, pseudoneglect was assessed based on MRT, which was calculated separately for the LVF and RVF for each condition and each study participant. Results. Adults with ADHD had overall slower MRT and increased RTV relative to NT. MRT and RTV improved under the fast/incentive condition. Both groups showed RVF-slowing with no between-group or between-conditions differences in RVF-slowing. Conclusion. Adults with ADHD exhibited pseudoneglect, a NT pattern of lateralization of attention, which was not attenuated by presentation speed and incentives.

Hydrothermal Sintering under Mild Temperature Conditions: Preparation of Calcium-deficient Hydroxyapatite Compacts

2010 ◽  
Vol 65 (8) ◽  
pp. 1038-1044 ◽  
Author(s):  
Kazumichi Yanagisawa ◽  
Jae-Hyen Kim ◽  
Chisato Sakata ◽  
Ayumu Onda ◽  
Eri Sasabe ◽  
...  
Keyword(s):  
Reaction Time ◽  
Reaction Temperature ◽  
Hot Pressing ◽  
Reaction Parameter ◽  
High Bulk Density ◽  
Temperature And Pressure ◽  
Mild Temperature ◽  
Short Time ◽  
High Bulk ◽  
Dissolution And Precipitation

Calcium-deficient hydroxyapatite (CDHA) prepared by the coprecipitation method was solidified by the hydrothermal hot-pressing technique, and compacts of CDHA with high bulk density beyond 80% were obtained at 200 ℃. Each reaction parameter, viz. reaction temperature, pressure, and time, was systematically changed from the standard conditions to investigate its effects on density, Vickers hardness, and Ca/P ratio of the compacts obtained. The reaction temperature and pressure had a large effect on densification, but not the reaction time because the densification proceeds in a short time. The densification by hydrothermal hot-pressing involved dissolution and precipitation of the starting CDHA powder, so that the Ca/P ratio changed from 1.52 of the starting powders to 1.61 of the compact obtained by hydrothermal hot-pressing at 200 ℃ and 35 MPa for 24 h with the addition of 10 wt.-% water

scholarly journals The role of intra-articular neuronal CCR2 receptors in knee joint pain associated with experimental osteoarthritis in mice

2021 ◽  
Vol 23 (1) ◽  
Author(s):  
Shingo Ishihara ◽  
Alia M. Obeidat ◽  
David L. Wokosin ◽  
Dongjun Ren ◽  
Richard J. Miller ◽  
...  
Keyword(s):  
Knee Joint ◽  
Sensory Neuron ◽  
Sensory Neurons ◽  
Direct Stimulation ◽  
Sensory Afferents ◽  
Neuronal Marker ◽  
The Right ◽  
Experimental Osteoarthritis ◽  
In Vivo Calcium Imaging

Abstract Background C–C chemokine receptor 2 (CCR2) signaling plays a key role in pain associated with experimental murine osteoarthritis (OA) after destabilization of the medial meniscus (DMM). Here, we aimed to assess if CCR2 expressed by intra-articular sensory neurons contributes to knee hyperalgesia in the early stages of the model. Methods DMM surgery was performed in the right knee of 10-week-old male wild-type (WT), Ccr2 null, or Ccr2RFP C57BL/6 mice. Knee hyperalgesia was measured using a Pressure Application Measurement device. CCR2 receptor antagonist (CCR2RA) was injected systemically (i.p.) or intra-articularly (i.a.) at different times after DMM to test its ability to reverse knee hyperalgesia. In vivo Ca2+ imaging of the dorsal root ganglion (DRG) was performed to assess sensory neuron responses to CCL2 injected into the knee joint cavity. CCL2 protein in the knee was measured by ELISA. Ccr2RFP mice and immunohistochemical staining for the pan-neuronal marker, protein gene product 9.5 (PGP9.5), or the sensory neuron marker, calcitonin gene-related peptide (CGRP), were used to visualize the location of CCR2 on intra-articular afferents. Results WT, but not Ccr2 null, mice displayed knee hyperalgesia 2–16 weeks after DMM. CCR2RA administered i.p. alleviated established hyperalgesia in WT mice 4 and 8 weeks after surgery. Intra-articular injection of CCL2 excited sensory neurons in the L4-DRG, as determined by in vivo calcium imaging; responses to CCL2 increased in mice 20 weeks after DMM. CCL2, but not vehicle, injected i.a. rapidly caused transient knee hyperalgesia in naïve WT, but not Ccr2 null, mice. Intra-articular CCR2RA injection also alleviated established hyperalgesia in WT mice 4 and 7 weeks after surgery. CCL2 protein was elevated in the knees of both WT and Ccr2 null mice 4 weeks after surgery. Co-expression of CCR2 and PGP9.5 as well as CCR2 and CGRP was observed in the lateral synovium of naïve mice; co-expression was also observed in the medial compartment of knees 8 weeks after DMM. Conclusions The findings suggest that CCL2-CCR2 signaling locally in the joint contributes to knee hyperalgesia in experimental OA, and it is in part mediated through direct stimulation of CCR2 expressed by intra-articular sensory afferents.

scholarly journals Electromyographic Evaluation of the Shoulder Muscle after a Fatiguing Isokinetic Protocol in Recreational Overhead Athletes

2021 ◽  
Vol 18 (5) ◽  
pp. 2516
Author(s):  
Sebastian Klich ◽  
Adam Kawczyński ◽  
Bogdan Pietraszewski ◽  
Matteo Zago ◽  
Aiguo Chen ◽  
...  
Keyword(s):  
External Rotation ◽  
Shoulder Girdle ◽  
Median Frequency ◽  
Shoulder Injury ◽  
Overhead Athletes ◽  
Upper Trapezius ◽  
Main Effect ◽  
Shoulder Girdle Muscles ◽  
Exercise Induced ◽  
The Right

The goal of our study was to examine the muscle activity of the shoulder girdle after isokinetic fatigue, which may simulate muscle activities commonly occurring during specific sport-related activities in recreational overhead asymptomatic athletes. We hypothesized that exercise-induced fatigue, reported after isokinetic protocols, may cause a decrease in the median frequency (MF) of the upper trapezius (UT), infraspinatus (IS), and deltoid muscles. Twenty-four male overhead volleyball (n = 8), handball (n = 8), and tennis (n = 8) athletes participated in this study. All subjects were without shoulder injury history. The surface electromyography (SEMG) was collected on the right (dominant) side of the shoulder girdle muscles in the following order: UT, IS and anterior (DA), and posterior deltoideus (DP). The fatigue protocol consisted of three sets of 32 maximum isokinetic concentric contractions while performing shoulder internal and external rotation at an isokinetic speed of 120 o/s. The resultant difference in median frequency (ΔMF) values consistently dropped after the fatiguing tasks across all recorded muscles, in terms of the initial MF (MFINI = 65.1 ± 1.1 Hz) and final MF (MFFIN = 57.9 ± 0.9 Hz), and the main effect of time was significant (F(1,22) = 43.15, p < 0.001). MF values decreased mostly for IS (ΔMFIS = −9.9 ± 1.6 Hz) and DP (ΔMFPD = −9.5 ± 1.9 Hz) muscles, while DA and UT showed smaller changes (ΔMFDA = −6.9 ± 1.5 Hz) and (ΔMFUT = −3.2 ± 1.3 Hz). The results of our study show a meaningful contribution in determining increased fatigue of the shoulder girdle muscles during repeated isokinetic internal-external rotation protocols. We have also demonstrated a significant decrease in MF in all examined muscles, especially IS and DA.

scholarly journals UNJUK KERJA REAKTOR PLASMA DIELECTRIC BARRIER DISCHARGE UNTUK PRODUKSI BIODIESEL DARI MINYAK KELAPA SAWIT

Teknik ◽  
2013 ◽  
Vol 34 (2) ◽  
pp. 116
Author(s):  
Ardian Dwi Yudhistira ◽  
Istadi Istadi
Keyword(s):  
Reaction Mechanism ◽  
Reaction Time ◽  
Product Yield ◽  
High Energy ◽  
Electrode Gap ◽  
Dbd Plasma ◽  
Electric Voltage ◽  
Batch System ◽  
Electro Catalysis ◽  
Short Time

Biodiesel is one of alternative renewable energy source to substitute diesel fuel. Various biodiesel productionprocesses through transesterification reaction with a variety of catalysts have been developed by previousresearcher. This process still has the disadvantage of a long reaction time, and high energy need. DielectricBarrier Discharge (DBD) plasma electro-catalysis may become a solution to overcome the drawbacks in theconventional transesterification process. This process only needs a short time reaction and low energy process.The purpose of this study was to assess the performance of DBD plasma rector in making biodiesel such as: theeffect of high voltage electric value, electrodes gap, mole ratio of methanol / oil, and reaction time. TheResearch method was using GC-MS (Gas Cromatography-Mass Spectrofotometry) and FTIR (FourierTransform Infrared Spectrofotometry) and then it will be analysed the change of chemical bond betweenreactant and product. So, the reaction mechanism can be predicted. Biodiesel is produced using methanol andpalm oil as reactants and DBD plasma used as reactor in batch system. Then, reactants contacted by highvoltage electric. From the results of this research can be concluded that the reaction mechanism occurs in theprocess is the reaction mechanism of cracking, the higher of electric voltage and the longer of reaction time leadto increasing of product yield. The more of mole ratio of methanol / oil and widening the gap between theelectrodes lead to decreased product yield. From this research, product yield maksimum is 89,8% in the variableof rasio mol metanol/palm oil 3:1, voltage 10 kV, electrode gap 1,5 cm, and reaction time 30 seconds.

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