Coupled objective function to study the role of abdominal muscle forces in lifting using the kinematics-driven model

2013 ◽  
Vol 16 (1) ◽  
pp. 54-65 ◽  
Author(s):  
Z. El Ouaaid ◽  
A. Shirazi-Adl ◽  
N. Arjmand ◽  
A. Plamondon
Keyword(s):  
Objective Function ◽  
Abdominal Muscle ◽  
Muscle Forces

Abstract P432: Higher Muscle-to-Abdominal Cavity Ratio is Associated with Lower Odds of Type II Diabetes in Older Women

Circulation ◽  
2013 ◽  
Vol 127 (suppl_12) ◽  
Author(s):  
Britta Larsen ◽  
Matthew Allison ◽  
Eugene Kang ◽  
Sarah Saad ◽  
Gail A Laughlin ◽  
...  
Keyword(s):  
Type Ii Diabetes ◽  
Abdominal Cavity ◽  
Abdominal Muscle ◽  
Normal Weight ◽  
Area Ratio ◽  
Type Ii ◽  
Obese Women ◽  
Abdominal Adipose Tissue ◽  
Race Ethnicity

Background: Excess abdominal adipose tissue has been identified as an important factor in the development of type II diabetes. Lean muscle tissue also plays an important role in glucose regulation, yet research on the role of muscle in diabetes etiology is limited. Abdominal muscle mass could be particularly relevant for normal weight diabetics, for whom excessive abdominal adipose tissue may play less of a role. Objective: To explore the association between muscle-to-abdominal cavity area ratio and prevalent diabetes in older community-dwelling women in the Rancho Bernardo Study, UCSD Filipino Women’s Health Study, and the Health Assessment Study of African-American Women. Methods: Participants were 421 women (40% Caucasian, 28% Filipina, 32% African American) with a mean age of 64 (6.9) years. Abdominal muscle and fat areas were measured using computed tomography (CT) scans, and were used to compute a muscle-to-abdominal cavity area ratio (MACR). Based on body mass index (BMI), participants were classified as normal weight (18-24.9 kg/m2), overweight (25-29.9), or obese (30+). Prevalent diabetes was defined as self-report of physician diagnosis, anti-diabetes medication use, fasting morning glucose ≥ 126 mg/dL or 2 hour glucose ≥ 200mg/dL. MACR was modeled per standard deviation (SD) and logistic regression was used to examine the association with diabetes while adjusting for relevant covariates. Results: Prevalent diabetes was seen in 12.8% of the sample (54 of 421). In age and race/ethnicity adjusted models, each SD increase in MACR was associated with significant reduced odds of diabetes (OR = 0.62, CI: 0.43-0.89, p = 0.01), which remained significant after further adjustment for BMI category, smoking, physical activity, hypertension, anti-hypertensive drugs, and estrogen use (OR = 0.64, CI: 0.41-0.98, p = .041). The association was modestly attenuated after further adjusting for visceral fat area (OR = 0.70, CI: 0.44-1.10, p = 0.12). Normal weight women with diabetes had significantly less total muscle (p = 0.045) and smaller MACR’s (p = 0.001) than those without diabetes, while this was not seen for overweight or obese women with diabetes. Stratified by BMI category, MACR was significantly associated with lower odds of diabetes for normal weight women across all three models (fully adjusted OR = 0.37, CI: 0.15-0.90, p =.03), yet was not associated with diabetes in any models for women who were overweight or obese (all p > 0.50). Interactions of MACR with race/ethnicity were not significant. Conclusions: Muscle-to-abdominal cavity ratio is associated with reduced likelihood of type II diabetes in women. This association differs by BMI category, with muscle showing the greatest protection in normal weight women, and no effect in overweight or obese women. This highlights the potential role of low muscle mass as a risk factor for diabetes, particularly in women who may appear to be at low risk.

Effects of postural changes and vestibular lesions on diaphragm and rectus abdominis activity in awake cats

2001 ◽  
Vol 91 (1) ◽  
pp. 137-144 ◽  
Author(s):  
L. A. Cotter ◽  
H. E. Arendt ◽  
J. G. Jasko ◽  
C. Sprando ◽  
S. P. Cass ◽  
...  
Keyword(s):  
Vestibular System ◽  
Muscle Activity ◽  
Abdominal Muscle ◽  
Rectus Abdominis ◽  
Abdominal Muscles ◽  
Body Rotation ◽  
Postural Changes ◽  
Before And After ◽  
Awake Cats

Changes in posture can affect the resting length of the diaphragm, requiring alterations in the activity of both the abdominal muscles and the diaphragm to maintain stable ventilation. To determine the role of the vestibular system in regulating respiratory muscle discharges during postural changes, spontaneous diaphragm and rectus abdominis activity and modulation of the firing of these muscles during nose-up and ear-down tilt were compared before and after removal of labyrinthine inputs in awake cats. In vestibular-intact animals, nose-up and ear-down tilts from the prone position altered rectus abdominis firing, whereas the effects of body rotation on diaphragm activity were not statistically significant. After peripheral vestibular lesions, spontaneous diaphragm and rectus abdominis discharges increased significantly (by ∼170%), and augmentation of rectus abdominis activity during nose-up body rotation was diminished. However, spontaneous muscle activity and responses to tilt began to recover after a few days after the lesions, presumably because of plasticity in the central vestibular system. These data suggest that the vestibular system provides tonic inhibitory influences on rectus abdominis and the diaphragm and in addition contributes to eliciting increases in abdominal muscle activity during some changes in body orientation.

INVESTIGATION OF THE INFLUENCE OF THE ELBOW JOINT REACTION ON THE PREDICTED MUSCLE FORCES USING DIFFERENT OPTIMIZATION FUNCTIONS

2009 ◽  
Vol 12 (01) ◽  
pp. 31-43 ◽  
Author(s):  
Rositsa T. Raikova
Keyword(s):  
Objective Function ◽  
Elbow Joint ◽  
Degrees Of Freedom ◽  
Sagittal Plane ◽  
Biomechanical Model ◽  
Moment Equation ◽  
Muscle Forces ◽  
Joint Stability ◽  
Biarticular Muscles ◽  
Joint Reaction

Less attention is paid to joint reactions when optimization tasks are solved aiming to predict individual muscle forces driving a biomechanical model. The reactions are important, however, for joint stability and for prevention from injuries, especially for fast motions and submaximal loading. The purpose of the paper is to investigate the influence of the joint reaction as a criterion in an objective function and to study the possibilities for prediction of antagonistic co-contraction. Planar elbow flexions in the sagittal plane with duration from 0.4 to 2 s are simulated, and muscle forces and elbow joint reaction are calculated solving numerically optimization tasks formulated for models with one (elbow moment equation only) and two (elbow and shoulder moment equations) degrees of freedom (DOF). The objective function is a weighted sum of muscle forces and joint reaction raised to different powers. The following conclusions can be made: (1) if the joint reaction is included in the objective function, antagonistic co-contraction can be predicted even for 1 DOF model; in some situations the use of such objective function can destroy the synergistic muscles' action; (2) the prediction of antagonistic muscles' co-contraction for 2 DOF model depends on the way the biarticular muscles are modeled, and this is valid for both dynamic and quasistatic conditions; if there are no biarticular muscles, antagonistic co-contraction cannot be predicted in one joint using popular objective functions, like minimum of sum of muscle forces or muscle stresses raised to a power.

Tachykininergic mediation of viscerosensitive responses to acute inflammation in rats: role of CGRP

1997 ◽  
Vol 272 (1) ◽  
pp. G141-G146 ◽  
Author(s):  
V. Julia ◽  
L. Bueno
Keyword(s):  
Acetic Acid ◽  
Gastric Emptying ◽  
Visceral Pain ◽  
Abdominal Muscle ◽  
Sodium Chromate ◽  
Sensory Afferents ◽  
Neurokinin Receptors ◽  
Calcitonin Gene ◽  
Reconstituted Milk

Tachykinins, colocalized with calcitonin gene-related peptides (CGRP) in sensory afferents, are involved in viscerosensitive responses. We investigated the role of tachykinins and CGRP in both nociceptive and visceromotor responses to inflammation. Visceral pain was assessed by abdominal muscle contractions. Gastric emptying was evaluated after gavage with reconstituted milk containing 51Cr-labeled sodium chromate. Acetic acid or 9% NaCl was injected intraperitoneally before the meal. RP-67580, SR-48968, human CGRP [hCGRP-(8-37)], or their vehicles were injected before acetic acid or saline. RP-67580, SR-48968, or their vehicles were injected before CGRP and the meal. GR-73632 or GR-76349 was injected before the meal. Acetic acids inhibited gastric emptying and increased the number of abdominal contractions. RP-67580 reduced the inhibition of gastric emptying without affecting the abdominal response. SR-48968 only reduced the acetic acid-induced increase of abdominal contractions. hCGRP-(8-37) reduced both responses induced by acetic acid. CGRP mimicked the effects of acetic acid. RP-67580 abolished CGRP-induced gastric emptying inhibition, whereas SR-48968 only diminished visceral pain. GR-73632 reduced gastric emptying, and GR-64349 increased abdominal response. In inflammation, neurokinin receptors (NK1 and NK2) mediate the gastric emptying inhibition and visceral pain, respectively. These responses involve a release of CGRP.

scholarly journals Implementasi Fuzzy C-Means dan Possibilistik C-Means Pada Data Performance Mahasiswa

2020 ◽  
Vol 6 (2) ◽  
pp. 39-48
Author(s):  
Gadis Retno Apsari ◽  
Mohammad Syaiful Pradana ◽  
Novita Eka Chandra
Keyword(s):  
Objective Function ◽  
Grade Point Average ◽  
Student Performance ◽  
Fuzzy Clustering ◽  
Performance Data ◽  
Grade Point ◽  
Fuzzy C Means ◽  
Student Performance Data ◽  
Minimum Objective Function

Students are the most important component in a university, especially private universities especially Universitas Islam Darul ‘ulum (Unisda) Lamongan. One of the most important roles of students for higher education is achievement. This study aims to determine the role of Fuzzy Clustering in classifying student performance data. The data includes GPA (Grade Point Average), ECCU (Extra-Curricular Credit Unit), attendance, and students' willingness to learn. So that groups of students who have the potential to have achievements can be identified. In this case, the grouping of student performance data uses Fuzzy Clustering by applying the Fuzzy C-Means (FCM) and Possibilistic C-Means (PCM) algorithms with the help of Matlab. In the FCM algorithm, the membership degree is updated so as to produce a minimum objective function value. Meanwhile, the PCM algorithm uses a T matrix, which shows the peculiarities of the data which are also based on minimizing the objective function.

Control of abdominal and expiratory intercostal muscle activity during vomiting: role of ventral respiratory group expiratory neurons

1987 ◽  
Vol 57 (6) ◽  
pp. 1854-1866 ◽  
Author(s):  
A. D. Miller ◽  
L. K. Tan ◽  
I. Suzuki
Keyword(s):  
Muscle Activity ◽  
Discharge Rate ◽  
Abdominal Muscle ◽  
Lumbar Spinal Cord ◽  
Abdominal Muscles ◽  
Ventral Respiratory Group ◽  
Before And After ◽  
The One ◽  
Lumbar Spinal

The role of ventral respiratory group (VRG) expiratory (E) neurons in the control of abdominal and internal intercostal (expiratory) muscle activity during vomiting was examined in decerebrate cats by recording from these neurons during fictive vomiting in paralyzed animals and comparing abdominal muscle activity during vomiting before and after sectioning the axons of these descending neurons. Fictive vomiting was defined by a series of bursts of coactivation of abdominal and phrenic nerves elicited by either subdiaphragmatic vagus nerve stimulation or emetic drugs. Such coordinated activity would be expected to produce vomiting if the animals were not paralyzed. Data were recorded from 27 VRG E neurons that were antidromically activated from the lower thoracic (T13) or lumbar spinal cord. During fictive vomiting, almost two-thirds of these neurons (17/27) were mainly active in between periods of abdominal and phrenic nerve coactivation, when the internal intercostal motoneurons are known to be active. This group of neurons was termed INT neurons. INT neurons were subdivided according to whether they were active between every burst of phrenic and abdominal nerve coactivation (INTa neurons, n = 10) or only between some bursts (INTb neurons, n = 7). Another one-third of the VRG E neurons had normal or increased levels of activity when the abdominal nerves were active during fictive vomiting (ABD neurons). The one remaining neuron was mainly silent throughout fictive vomiting. ABD neurons were indistinguishable from INT neurons on the basis of their location in the VRG, type of firing pattern (ramp versus step ramp), conduction velocity, or extent of projection in the lumbar cord. However, INTa neurons had a significantly higher discharge rate during respiration than either ABD or INTb neurons. Abdominal muscle EMG and nerve activity were recorded from six unparalyzed cats before and after cutting the axons of VRG E neurons as they cross the midline between C1 and the obex. The lesions abolished or almost eliminated expiratory modulation of abdominal muscle activity. In contrast, the abdominal muscles were always active during vomiting; however, the amplitude of postlesion abdominal activity varied from approximately 70-100% of prelesion values in three cats to 60-70% of normal in a fourth animal to only approximately 20% of prelesion values in two other cats.(ABSTRACT TRUNCATED AT 400 WORDS)

Behavior of upper cervical inspiratory propriospinal neurons during fictive vomiting

1991 ◽  
Vol 65 (6) ◽  
pp. 1492-1500 ◽  
Author(s):  
S. Nonaka ◽  
A. D. Miller
Keyword(s):  
Firing Pattern ◽  
Impulse Activity ◽  
Abdominal Muscle ◽  
Lateral Funiculus ◽  
Upper Cervical ◽  
Spinal Segments ◽  
Propriospinal Neurons ◽  
Lumbar Cord ◽  
Stimulation Of

1. The role of upper cervical inspiratory (UCI)-modulated neurons in respiratory muscle control during vomiting was examined by recording the impulse activity of these neurons during fictive vomiting in decerebrate, paralyzed cats. Fictive vomiting was identified by a characteristic series of bursts of coactivation of phrenic and abdominal muscle nerves, elicited either by electrical stimulation of supradiaphragmatic vagal nerve afferents or by emetic drugs, which would be expected to produce expulsion of gastric contents in nonparalyzed animals. 2. Data were recorded from 43 propriospinal UCI neurons, located in the C1-C3 spinal segments near the border of the intermediate gray matter and lateral funiculus, which were antidromically activated with floating pin electrodes placed in the ipsilateral lateral funiculus, usually at T1-T3. Some cells (9/21 tested) were also activated from the upper lumbar cord (L1). During respiration, most neurons (n = 40) had an augmenting discharge pattern during inspiration. In addition, more than one-half (55%) fired tonically during the remainder of the respiratory cycle. About 40% of UCI neurons showed variations in their firing pattern during the noninspiratory portion of respiration. These latter two properties of UCI neurons were not observed in dorsal and ventral respiratory group (DRG and VRG-, respectively) bulbospinal inspiratory (I) neurons previously recorded under similar conditions. 3. During fictive vomiting, the firing pattern of most UCI neurons fell into one of three main categories. More than one-half (53%) were active in phase with bursts of phrenic discharge and were thus classified as Active-type cells.(ABSTRACT TRUNCATED AT 250 WORDS)

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