Links between the Mechanics of Ventilation and Spine Stability

2008 ◽  
Vol 24 (2) ◽  
pp. 166-174 ◽  
Author(s):  
Simon Wang ◽  
Stuart M. McGill
Keyword(s):  
Muscle Activation ◽  
Stability Index ◽  
Motor Patterns ◽  
Lung Inflation ◽  
Spine Stability ◽  
Hand Force ◽  
Low Levels ◽  
Male Subjects ◽  
Back Extensor

Spine stability is ensured through isometric coactivation of the torso muscles; however, these same muscles are used cyclically to assist ventilation. Our objective was to investigate this apparent paradoxical role (isometric contraction for stability or rhythmic contraction for ventilation) of some selected torso muscles that are involved in both ventilation and support of the spine. Eight, asymptomatic, male subjects provided data on low back moments, motion, muscle activation, and hand force. These data were input to an anatomically detailed, biologically driven model from which spine load and a lumbar spine stability index was obtained. Results revealed that subjects entrained their torso stabilization muscles to breathe during demanding ventilation tasks. Increases in lung volume and back extensor muscle activation coincided with increases in spine stability, whereas declines in spine stability were observed during periods of low lung inflation volume and simultaneously low levels of torso muscle activation. As a case study, aberrant ventilation motor patterns (poor muscle entrainment), seen in one subject, compromised spine stability. Those interested in rehabilitation of patients with lung compromise and concomitant back troubles would be assisted with knowledge of the mechanical links between ventilation during tasks that impose spine loading.

Low Temperature Fault Isolation Using Soft Defect Localization

2012 ◽  
Author(s):  
Kristopher D. Staller
Keyword(s):  
Low Temperatures ◽  
Laser Scanning ◽  
Low Cost ◽  
Fault Isolation ◽  
Laser Scanning Microscopy ◽  
Cold Temperature ◽  
Multiple Point ◽  
Defect Localization ◽  
Low Levels

Abstract Cold temperature failures are often difficult to resolve, especially those at extreme low levels (< -40°C). Momentary application of chill spray can confirm the failure mode, but is impractical during photoemission microscopy (PEM), laser scanning microscopy (LSM), and multiple point microprobing. This paper will examine relatively low-cost cold temperature systems that can hold samples at steady state extreme low temperatures and describe a case study where a cold temperature stage was combined with LSM soft defect localization (SDL) to rapidly identify the cause of a complex cold temperature failure mechanism.

The impact of phosphorus deficiency on nitrification - case study of a biological pretreatment plant for rendering plant effluent

1996 ◽  
Vol 34 (1-2) ◽  
pp. 229-236 ◽  
Author(s):  
O. Nowak ◽  
K. Svardal ◽  
H. Kroiss
Keyword(s):  
Activated Sludge ◽  
Nitrogen Removal ◽  
Phosphorus Deficiency ◽  
Extended Model ◽  
Biological Pretreatment ◽  
Dynamic Conditions ◽  
Low Levels ◽  
The Impact ◽  
Kinetics Of

The highly concentrated wastewater of a rendering plant (7 g COD/l and 1.1 g TKN/l on average) is biologically pretreated in an activated sludge plant. Due to low loading of this plant, full nitrification and nitrogen removal are generally achieved. In periods of high COD loads, however, the nitrification capacity was substantially reduced. Control analyses revealed extreme phosphorus deficiency and that only nitrite, but no nitrate was formed. An extended model based on the ‘Activated sludge model No. 1’ has been used to investigate the kinetics of nitrification in the case of phosphorus deficiency, the demand for phosphorus under dynamic conditions, as well as the effect of variations in the nitrogen load at low levels of phosphate.

Electrically evoked isokinetic plantar flexor torque in males

1987 ◽  
Vol 63 (4) ◽  
pp. 1499-1503 ◽  
Author(s):  
D. O. Thomas ◽  
M. J. White ◽  
G. Sagar ◽  
C. T. Davies
Keyword(s):  
Angular Velocity ◽  
Muscle Activation ◽  
Triceps Surae ◽  
Plantar Flexor ◽  
Velocity Data ◽  
Exponential Equation ◽  
Isometric Torque ◽  
The Mean ◽  
Electrical Stimuli ◽  
Male Subjects

The involuntary angle-specific isokinetic plantar flexor torques of seven male subjects aged 18–21 yr were measured using a Cybex II dynamometer (Lumex) modified by the addition of a strain-gauge load cell to improve the dynamic response of the instrument. Supramaximal electrical stimuli were used to evoke a maximal tetanic response from the triceps surae and ensure constant muscle activation at each angular velocity studied. Angle-specific torques were measured over a range (0.5–5.0 rad/s) of preset velocities, torque decreasing in a nonlinear manner with increasing angular velocity. The torque-velocity data was adequately described by an exponential equation of the form: V = a(e-1/b - e-Po/b) where V = velocity (rad/s), P = torque (N.m), Po = isometric torque (N.m), and a and b are constants. The mean intrasubject coefficient of variation of torque over the range of velocities studies was 7.9 +/- 1.88% (SD).

scholarly journals Platiniferous Tetra-Auricupride: A Case Study from the Bolshoy Khailyk Placer Deposit, Western Sayans, Russia

Minerals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 160 ◽  
Author(s):  
Andrei Barkov ◽  
Nobumichi Tamura ◽  
Gennadiy Shvedov ◽  
Camelia Stan ◽  
Chi Ma ◽  
...  
Keyword(s):  
Intermetallic Compounds ◽  
Elevated Level ◽  
Unit Cell ◽  
Geochemical Evolution ◽  
Significant Modification ◽  
Unit Cell Parameters ◽  
Cell Parameters ◽  
Low Levels ◽  
First Time

Tetra-auricupride, ideally AuCu, represents the only species showing the coexistence of Au with an elevated level of Pt, as in the case of a detrital grain studied structurally for the first time, from an ophiolite-associated placer at Bolshoy Khailyk, western Sayans, Russia. We infer that tetra-auricupride can incorporate as much as ~30 mol. % of a “PtCu” component, apparently without significant modification of the unit cell. The unit-cell parameters of platiniferous tetra-auricupride are: a 2.790(1) Å, c 3.641(4) Å, with c/a = 1.305, which are close to those reported for ordered AuCu(I) in the system Au–Cu, and close also to the cell parameters of tetraferroplatinum (PtFe), which both appear to crystallize in the same space group, P4/mmm. These intermetallic compounds and natural alloys are thus isostructural. The closeness of their structures presumably allows Pt to replace Au atoms so readily. The high extent of Cu + Au enrichment is considered to be a reflection of geochemical evolution and buildup in levels of the incompatible Cu and Au with subordinate Pt in a remaining volume of melt at low levels of fO2 and fS2 in the system.

scholarly journals Forelimb muscle function in pig-nosed turtles, Carettochelys insculpta : testing neuromotor conservation between rowing and flapping in swimming turtles

2013 ◽  
Vol 9 (5) ◽  
pp. 20130471 ◽  
Author(s):  
Angela R. V. Rivera ◽  
Richard W. Blob
Keyword(s):  
Muscle Function ◽  
Muscle Activation ◽  
Sea Turtles ◽  
Freshwater Species ◽  
Motor Patterns ◽  
Activation Patterns ◽  
Muscle Activation Patterns ◽  
Superficial Similarity ◽  
Apalone Ferox ◽  
Do So

Changes in muscle activation patterns can lead to new locomotor modes; however, neuromotor conservation—the evolution of new forms of locomotion through changes in structure without concurrent changes to underlying motor patterns—has been documented across diverse styles of locomotion. Animals that swim using appendages do so via rowing (anteroposterior oscilations) or flapping (dorsoventral oscilations). Yet few studies have compared motor patterns between these swimming modes. In swimming turtles, propulsion is generated exclusively by limbs. Kinematically, turtles swim using multiple styles of rowing (freshwater species), flapping (sea turtles) and a unique hybrid style with superficial similarity to flapping by sea turtles and characterized by increased dorsoventral motions of synchronously oscillated forelimbs that have been modified into flippers ( Carettochelys insculpta ). We compared forelimb motor patterns in four species of turtle (two rowers, Apalone ferox and Trachemys scripta ; one flapper, Caretta caretta ; and Carettochelys ) and found that, despite kinematic differences, motor patterns were generally similar among species with a few notable exceptions: specifically, presence of variable bursts for pectoralis and triceps in Trachemys (though timing of the non-variable pectoralis burst was similar), and the timing of deltoideus activity in Carettochelys and Caretta compared with other taxa. The similarities in motor patterns we find for several muscles provide partial support for neuromotor conservation among turtles using diverse locomotor styles, but the differences implicate deltoideus as a prime contributor to flapping limb motions.

Electromyographic evaluation of approach stride, jump stride and intermediate stride in selected superficial muscles of the jumping horse: a preliminary study

2013 ◽  
Vol 9 (1) ◽  
pp. 23-32 ◽  
Author(s):  
L. St. George ◽  
J.M. Williams
Keyword(s):  
Muscle Activation ◽  
Motor Unit Action Potential ◽  
Maximum Height ◽  
Training Methods ◽  
Triceps Brachii ◽  
Signed Rank ◽  
Motor Unit Action ◽  
Preliminary Study ◽  
Insight Into

The horse's ability to execute the diverse physical demands of jumping is greatly influenced by muscular adaptations to training. The aim of the study was to provide preliminary insight into potential differences in the functional activity of muscles recruited during phases of the equine jumping effort. An exploratory case study was conducted to investigate muscle activity and recruitment in one jumping horse, experienced in 1.40 m competition. Wireless sEMG electrodes were utilised to quantitatively investigate the degree of muscle activation by recording potentials from the Superficial gluteal (SG), Triceps brachii (TB) and Longissimus dorsi muscles. Data were collected as the horse executed a related combination of fences with a maximum height of 1.25 m. Mean motor unit action potential (mMUAP) and mean peak amplitude frequency (PAF) were determined for each muscle during approach, jump and intermediate strides, and were analysed using Friedman and Wilcoxon Signed Rank tests to establish whether significant differences occurred between strides. Statistical analyses did not reveal significant differences between mMUAP values for muscles investigated across strides (P≯0.05). However, significant differences were found for mean PAF values in the left SG between approach and jump strides (P<0.025), and between jump and intermediate strides (P<0.025) in the left TB. The lack of significant differences between strides may reflect the theory that the jump stride is a form of extended suspension incorporated into the canter stride and may support current anecdotal training methods of the jumping horse, which place emphasis on developing a regular and collected canter. However, results from this study were based on one horse and therefore application to the wider population of jumping horses should be undertaken with caution until further research in more subjects is conducted to support the results from this preliminary study.

Lack of Effects of Carbon Monoxide on Human Vigilance

1977 ◽  
Vol 45 (3) ◽  
pp. 1007-1014 ◽  
Author(s):  
Vernon A. Benignus ◽  
David A. Otto ◽  
James D. Prah ◽  
Gayla Benignus
Keyword(s):  
Carbon Monoxide ◽  
Critical Review ◽  
Statistical Test ◽  
Review Of The Literature ◽  
Vigilance Performance ◽  
Monitoring Task ◽  
Human Male ◽  
Exposure Levels ◽  
Low Levels ◽  
Male Subjects

Previous publications on the effects of low levels of carbon monoxide (CO) on human vigilance performance have found conflicting results. While several studies have found statistically reliable effects, none have gone unchallenged. This article presents a critical review of the literature and the results of a study employing 52 human male subjects performing a numeric monitoring task. CO levels were 0, 100, and 200 ppm which produced mean carboxyhemoglobin levels 0.01, 4.61 and 12.62 percent respectively. No CO-exposure levels produced any effect on vigilance performance. The power of the statistical test for CO effects was shown to be quite high, even for fairly trivial possible decrements of performance.

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