Biomechanical analysis of technique

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Biomechanical analysis of acromioclavicular joint dislocation repair using coracoclavicular suspension devices in two different configurations

Biomechanical analysis of acromioclavicular joint dislocation repair using coracoclavicular suspension devices in two different configurations

A large number of AC dislocation repair techniques have been described, but there is still controversy over what the standard technique should be. Generally, repair focuses on reinforcing the CC ligaments with non-ab- sorbable sutures, screws, pins, plates, or other methods of internal fixation [13–15]. Repairs with tendon grafts or fixation devices are based on the Weaver–Dunn technique and its variations [16, 17]. Initially, these coracoclavicular suspension devices were described for tibiofibular syn- desmosis repair, but they have since been used in AC joint reconstruction too [18, 19]. Authors such as Salzmann [5] and Walz [12] argue that the placement of two CC sus- pension systems as replacements for the conoid and trapezoid ligaments is required to achieve proper primary stability. The precise anatomy of these two CC ligaments has already been described: the length of each ligament should be about 10 mm, giving a distance of 10–15 mm between the clavicle and coracoid [1, 5, 9, 12]. In agree- ment with a study by Breslow [20], the AC capsule and its ligaments work together to maintain horizontal stability, while the CC ligaments limit vertical displacement. Di- makopoulos et al. [21] were the first to provide clinical data on double-bundle repair for acute AC dislocations. The Mazzoca group [3, 7] described the open clamp technique with a semitendinosus tendon which, despite using an anatomic collarbone implementation, only uses a single point of traction on the coracoid. Lafosse et al. [22] re- ported a modified Weaver–Dunn technique performed arthroscopically, while Choi et al. [23] described proce- dures that use suture fixations to repair acute dislocations of the AC complex, with two sutures placed in the ana- tomic position to provide primary stability of the AC and CC ligaments. Recently, Tomlinson [24] and Baumgarten [25] described the anatomic repair of the CC complex
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5 Lee mas

Thorax, pelvis and hip pattern in the frontal plane during walking in unilateral transtibial amputees: biomechanical analysis.

Thorax, pelvis and hip pattern in the frontal plane during walking in unilateral transtibial amputees: biomechanical analysis.

A potential limitation of this study was the model and the inverse dynamics technique, particularly in this context, in which there were both sound and prosthetic components. Furthermore, the placing of knee and ankle markers on the prosthesis at a location corresponding to the sound side might have affected the calculation of the joint centers. Additionally, the heterogeneous cohort and small sample size impeded the control of potential confounders, such as different times since amputation and since the current and first prosthesis prescription, differences in ages, differences in etiology of amputation and different prosthetic components. These aspects were not standardized across subjects. This conjuncture may affect our results as it will contribute to additional between-subject variance. Another limitation is the variability of the data. In our study, the standard deviation even in the control population was very high for some parameters.
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7 Lee mas

Monitoring treatment of vocal fold paralysis by biomechanical analysis of voice

Monitoring treatment of vocal fold paralysis by biomechanical analysis of voice

and respiratory organs, and a periodic or quasi-periodic inspection of voice quality improvements. Sometimes other interventions as minor surgery are required. The inspection purpose is to evaluate the patient and the process. The surgical and physical interventions have a corrective character. The inspection process in itself has been based mainly on the ability of the speech therapist to subjectively evaluate certain aspects of patient’s voicing, as (timbre, loudness, mucosal wave presence, glottal closure, roughness, breathiness, grade of dysphonia, etc.), and produce a graduation on a specific scale [1] for further use in comparing subsequent inspections of patient’s voice production separated some weeks or even months. This methodology is prone to statistical dispersion due to its strong dependency on the specific circumstances affecting the speech therapist in the precise evaluation process (stress, rush, awareness, etc.). The work presented here is an exploratory study conducted to show the possibilities of using advanced signal processing tools to extract important biomechanical information from the patient’s voicing, which may provide objective indices to judge on the quality of voice and on the progress or regress of corrective treatment and complementary rehabilitation techniques. A longitudinal case of a patient having lost the phonation function as a collateral effect following a cardio-vascular major surgery has been studied using biomechanical indices to objectively evaluate voice restoration. Indices estimated using the tool BioMet®Phon [2] as pitch, jitter, shimmer, noise-to-harmonic or mucosal wave ratios, as well as vocal fold biomechanics and glottal closure during vowel phonation allow depicting a colourful and highly semantic diagram of the rehabilitative process. The paper is organized as follows: A brief overview of the technique fundamentals is given in section 2. A description of the treatment methodology is given in section 3. In section 4 results obtained from the study case are presented, and their potential use discussed. Conclusions are presented in section 5.
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10 Lee mas

Implementation of a robust technique for dosimetric   evaluation of low.energy photon sources

Implementation of a robust technique for dosimetric evaluation of low.energy photon sources

Initially, the process started by cleaning the heating bed and nozzle at every attempt of printing and also configuring the position of the nozzle, which will need to have a distance of about 0.32 mm from the heating bed; temperatures were setup and the imported Gcode which is used for numerical control (It coordinates the position of the extruder, high of the heating bed and the temperature regulation) of the model in order to start printing the model. All of the pieces needed to be printed with a brim and the some of them with a supporting structure, the first one in order to improve the adhesion of the first layer and the second one was used because one of the structures did not have a flat face in which the whole structure could be supported. When the printing process starts it is necessary to verify that the extruded material is flowing correctly, when finishing, the model can be removed from the heating bed with the help of a spatula. Fig. 3-14
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61 Lee mas

Razón Vital de la Técnica / Vital Rationale of the Technique

Razón Vital de la Técnica / Vital Rationale of the Technique

Abstract: The aim of this paper is the understanding of the technique from Ortega's vital reason point of view. The conditions of the technique and its characters will be established. In the next pages will also be exposed the main ideas of Ortega concerning the technique: the need of the superfluous, life as freedom and project; the instrumental character of technique and the unlikelihood of a technocracy. Neither the technique nor the technicians are able to exert the spiritual power, because they cannot provide life's purposes.
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6 Lee mas

A new technique of laparoscopic surgery for rectal disease

A new technique of laparoscopic surgery for rectal disease

We have done laparoscopic surgery for colon disease since 1996. Although being cautious, laparoscopic procedure of rectal disease had to be modified because this one in an indistinct view at the narrow space of the pelvis has the possibility of making a trauma to bowel with the forceps used or an unexpected bleeding. For these reasons we had to create several techniques to get a better view of the pelvis. With these techniques we performed laparoscopic surgery for colorectal cancer type T1 or T2, as well as surgery for benign rectal disease.

5 Lee mas

Improved time resolved acousto optic technique for optical fiber analysis of axial nonuniformities by using edge interrogation

Improved time resolved acousto optic technique for optical fiber analysis of axial nonuniformities by using edge interrogation

It is worth to note that broadening of the elastic packet due to group-velocity dispersion of the flexural mode affects the length resolution of the technique. For our experimental conditions, however, this effect is small. After 1 m, the duration of the elastic packet, and consequently the resolution in length, increases just about 3%. However, it is an issue to be taken into account when shorter packets are used, or longer fiber lengths are analyzed. 4. Conclusion

6 Lee mas

Modification of the technique for subclavian vein catheterization

Modification of the technique for subclavian vein catheterization

There were five technical failures and compli- cations in 42 patients (11.9%). When we compa- red the results in our study with the total amount of complications and technical failures reported by Mansfield et al (21.8%), we found that there was a statistically significant differen- ce (p = 0.000019). These data are of complicatio- ns and technical failures that occurred without ultrasound guidance. This same author states that using ultrasound complications and techni- cal failures are 22.1%, which differs statistically from our results (p = 0.000011) Mansfield states that out of 821patients, they had 47 complicatio- ns and 105 that were not catheterized or out of place for a total of 152, which is 18.5%; this di- ffers significantly from the 11.9% found in our study (p = 0.000066).
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6 Lee mas

Estimation of hygroscopic of electrotechnical materials by dynamic speckle technique

Estimation of hygroscopic of electrotechnical materials by dynamic speckle technique

Dynamic speckle patterns are generated by laser light scattering on surfaces that exhibit some kind of activity [1]. Is it a typical phenomenon observed when a laser light illuminate biological tissues [2], but it is also present in several industrial cases. Besides, the temporary evolution of speckle patterns, attributed to the presence of mobile scatters, is an interesting tool for characterization of mineral properties [3].

1 Lee mas

Analysis of inspection technique performance

Analysis of inspection technique performance

reading techniques are [1, 4]: checklist-based and scenario-based techniques. The scenario-based techniques are further divided into perspective-based, use-based and defect-based reading techniques. A number of researchers have now developed experimental studies to compare the performance of the different testing techniques in an attempt to find out what is the best strategy to adopt in which cases. Also they have developed surveys comparing testing techniques with inspection techniques [5]. Yet nobody has so far conducted a study to compare the performance of different reading techniques with each other. Additionally, the above survey papers are qualitative (closely connected to the researcher’s opinion), even though there are enough existing studies to conduct a quantitative survey based on meta-analysis. This would make the evidence gathered from the aggregation process more reliable.
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10 Lee mas

Surveillance system biomechanical risk factors

Surveillance system biomechanical risk factors

Riesgo alto por exceso de horas laboradas al día NO Debe de ingresar al programa de pausas activas establecido por la compañía Fuerza ejercida en el trabajo dinámico por manip[r]

22 Lee mas

Biomechanical reference standards for early diagnosis of disturbances of balance: pilot study

Biomechanical reference standards for early diagnosis of disturbances of balance: pilot study

The postur instability and body balance alteration, are signs commonly observed in patients with diseases asso- ciated with the musculoskeletal, visual, vestibular and proprioceptive systems, being the stabilometry the main clinical assessment study. However, it has not been established a standard or a quantitative pattern to classify healthy and pathological subjects based on the impaired balance level. Objective: The main objective of this study was to conduct a preliminary stabilometric analysis in 38 healthy subjects (19 women and 19 men) in order to identify a characteristic pattern of the position displacement. Methodology: This study was based on the Rombergś test. Three measurements was performed to each patient with open eyes (OA) and eyes closed (OC) stand over a force platform. Results: A characteristic pattern of the medio-lateral X and anteroposterior Y movement was iden- tified, and remarkable stability on the vertical axis Z around the center of pressure. Limitations: However, because of the small sample size there was not found conclusive results related to Body-Mass-Index, sex or age. Originality: Despite, promising parameters were found for the evaluation of stabilometry in healthy young people, strengthe- ning the objective tools of clinical assessment. Conclusion: This research identified common patient characteris- tics of normal movement, that could be considered as an objective standard for patient monitoring and treatment evaluation in patients with pathological balance disorders.
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10 Lee mas

A biomechanical model of the upper limb applied to the handcycling

A biomechanical model of the upper limb applied to the handcycling

Regarding the muscle analysis we supposed a lot of parameters: PCSA, specific force and moment arm, all these assumptions obviously influenced the result of the 2D study, especially considering that in AnyBody each muscular fascicle has its own set of parameters (PCSA, specific force and moment arm). The last two problems that may affect the comparison are: the fact that anyway the results of the inverse dynamics (generated torques) are different, this clearly changes the force intensity of the muscles considered; another important thing is that, for instance, contrary to popular belief, the biceps brachii is not the most powerful flexor of the forearm, its function is primarily as a powerful supinator of the forearm; in the 2D model we select as a factor of minimization the ratio between the muscular forces and the maximum tensions generable, without using a weight parameter in order to select how much the single muscles take part in the total action produced, considering their main normal function. Consequently the dissimilarities represented in Figure 105 can be attributed to all the causes listed above.
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105 Lee mas

Analysis of fatty acids methyl esters standardization by the gas chromatography coupled to mass spectrometry technique

Analysis of fatty acids methyl esters standardization by the gas chromatography coupled to mass spectrometry technique

A fatty acids methyl esters (FAME’s) analysis standardization was made by gas chromatography-mass spectrometry (GC-MS), using electronic (EI) and chemical ionization (CI). Accuracy, linearity, detection and quantification limit, sensibility and correlation coefficient were evaluated as statistical parameters. Results showed that the EI analysis exhibits satisfactory statistical values for identification and quantification of FAME’s. However, FAME’s mass spectra have [M + 1 ] + as a molecular ion and don’t have common ions; for this reason the FAME’s identification through CI is easier. The real sample was chrysalises’ Bombix mori Linn soil obtained from Hybrid Pilamo 1 chrysalises growth in the coffee growing region of Colombia. The oil showed both oleic and palmitic acids as main components (43,752 y 26,300% respectively).
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6 Lee mas

Análisis biomecánico del efecto de las zapatillas de clavos en el rendimiento del esprint en hombres velocistas. [Biomechanical analysis of spikes shoe´s effects on the sprint performance of male sprinters].

Análisis biomecánico del efecto de las zapatillas de clavos en el rendimiento del esprint en hombres velocistas. [Biomechanical analysis of spikes shoe´s effects on the sprint performance of male sprinters].

The purpose of the present study was to quantify the effect of the use of spikes on sprint performance in male athle- tes, separating between both cleats and mass effects; additionally, the influence of the footwear on biomechanical para- meters of running was analyzed. Nine male regional-national sprint athletes (i.e., 100, 200 and 400 m distances) par- ticipated in this study, they performed three 40 m sprints in a randomized order (i.e., spikes, running shoes and mass- added spikes). Performance improved 2,6% with spikes with respect to running shoes, where 1,7% was due to the cle- ats and 0,9% was due to the mass. When analyzing the biomechanical variables, it was observed that the speed incre- ased because both step rate and step length also increased. Step length increased and the contact time decreased due to a combined effect of the cleats and the mass. In conclusion, the sprint performance improved when using spikes with respect to running shoes, two third of the improvement was due to the cleats, and the rest to the shoe’s mass. Key words: spikes, biomechanics, sprint, performance.
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13 Lee mas

A review of risk factors for hamstring injury in soccer: a biomechanical approach

A review of risk factors for hamstring injury in soccer: a biomechanical approach

running at 80% of his maximum velocity. It is obvious from Equation 5, that activation of quadriceps and the synchronization with the hamstrings are also crucial for the loads supported by each of the hamstring body muscles. However, a lack of information exists in the scientific literature about hamstrings and quadriceps activation during isokinetic tests in soccer (Oliviera et al. 2009). However, the muscle forces have been studied using simultaneously isokinetic and electromyography measures in sports as Australian Football or Track and Field but not in soccer (Opar et al., 2013, Kellis et al., 1998, Onishi et al., 2002, Hassani, et al. 2006, Sole et al. 2011, Oliveria, et al. 2012). It has been found that electromyographic activation of biceps femoris during eccentric contraction was smaller in the previously injured leg (Opar et al., 2013). A reduction on the electrical activity means a decrease in the recruitment number of motor units and/or a decrease in the stimulation frequency of fiber(Opar et al. 2013). More research is needed to demonstrate that a reduction on the electric activity of the muscle represents more risk of hamstring injury (Opar, 2012). Oliveira et al (2009) studied the force and electromyographic response of hamstrings and quadriceps during isometric contraction in 10 professional players. They found a strong relationship between the H:Q ratios calculated from the isometric force and from EMG records. The isometric force H:Q ratio reached values of 0.6 while EMG ratios ranged between 0.8 and 1.0. In accordance with Oliviera et al. (2009), the EMG activation patterns should be taken into consideration when the rehabilitation and prevention exercises are being designed.
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23 Lee mas

TítuloMatrix pseudo inversion technique for diagnostics of planar arrays

TítuloMatrix pseudo inversion technique for diagnostics of planar arrays

In this paper we show, by means of numerical simulation, that the Moore-Penrose pseudoinverse of a matrix taken from an overdetermined system can be applied to retrieve the excitation distribution of a planar array of parallel dipoles with faulty elements, by measuring the complex radiated field in its near zone. Failures on voltage (considering mutual coupling) and currents of several elements, and systematic or random measurement errors are considered in the simulation.

9 Lee mas

Corneal biomechanical properties : Measurement, modification and simulation

Corneal biomechanical properties : Measurement, modification and simulation

images. The analysis is based on a direct comparison between the stable non-deformed cornea immediately before the deformation event, and the corneal deformation during the air puff. The corneal thickness (1, red) is obtained as the axial distance between the anterior and posterior surface of the cornea, evaluated at the corneal apex before the deformation, during maximum deformation, and immediately after the deformation. The deformation amplitude (4, red) at the corneal apex represents the maximum deformation depth. This instant of maximum deformation (corresponding to the moment when the deformation stops increasing and starts decreasing, i.e., when the cornea starts recovering) divides the overall deformation (9) event in two intervals: the increasing deformation period (7) and the decreasing deformation period (8). The mean increasing and decreasing deformation speeds (2 and 6, black) are obtained as the deformation amplitude divided by the duration of the corresponding increasing or decreasing deformation period (slopes of the black lines in Figure 2.15a). The peak deformation speeds (3 and 5, orange) are also obtained for the increasing and decreasing deformation periods (as the maximum positive and negative slopes of the deformation curve, represented as orange lines in Figure 2.15a). The parameters above were obtained from high-speed A-scan measurements at the corneal apex throughout (Figure 2.15a). Additional information could be extracted from the dynamic B-scan measurements (along the horizontal meridian; Figure 2.15b). This imaging mode provided a direct view of the spatial deformation of the cornea. Although this corneal meridian measurement mode could potentially provide similar results about the apex dynamics than the A-scan measurements, the temporal sampling achievable is much lower and therefore the extracted parameters have lower precision. The B-scans were used to obtain the diameter of the deformed zone (10, green), the displaced corneal volume at the moment of peak deformation (11, gray), the non-deformed corneal radius (12) and the peak deformed
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352 Lee mas

Analysis of the haemodynamic and biomechanical properties of the lumina in aortic dissections using an integrated approach focussing on the complementary value of in-silico, in-vitro and invivo assessments

Analysis of the haemodynamic and biomechanical properties of the lumina in aortic dissections using an integrated approach focussing on the complementary value of in-silico, in-vitro and invivo assessments

Abstract - A persistent false lumen (FL) is present in 70-80% of patients discharged after an acute aortic dissection and most of these patients have high risk of mid/long-term complica- tions. FL flow starts to be assessable with MRI, but little is known on its determinants and pre- dictive value. We investigated the origin of cyclic variations in the intraluminal flow patterns in chronic aortic dissections using a computational lumped-parameter model. For this, we as- sessed the changes in flow profiles induced by several key properties of dissected aortas, poten- tially involved in FL enlargement, such as wall stiffness, tear size and location and the presence of abdominal side branches arising from the FL. The time course of the directions of the flow within the FL is highly dependent on the position of assessment along the aorta. From the par- ametric study, we found that FL flow patterns (especially at the level of the diaphragm) showed their characteristic patterns due to variations in the cumulative size and spatial distribution of the communicating tears and the incidence of visceral side branches originating from the FL. Interestingly, changes in wall stiffness did not change the time course of flows whereas it signif- icantly determined intraluminal pressures. FL flow patterns vary depending on the place of assessment along the dissection and are mostly influenced by the size and spatial distribution of tears and abdominal side branches. This data should be taken into consideration in the imaging protocol to define the predictive value of FL flows.
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142 Lee mas

Fundamental analysis of Repsol

Fundamental analysis of Repsol

pact. Furthermore, they have used a model to observe this effect, which results quite different depending on the reason that caused the oil price change (underly- ing shock). In the same atmosphere, Lippi and Nobili (2009) have followed their steps and focused on the oil price effect depending on the shock they suffer. For some other researchers, this effect caused a negative impact over the world economy itself. As Hamilton (2003) developed in his study about the oil shock, he accuses this fact to several recessions in the USA. Specially, his paper tries to explain the relation between oil prices and the macroeconomic variable Gross Domestic Product (GDP) growth, arguing that when forecasting the GDP growth, the most accurate option, but not the only one, is using a nonlinear function of oil price changes. Moreover, Hamilton’s paper said that the increase of movements in oil prices represent a more significant effect than the decreases one when calculating the GDP growth. Finally, he ended with the conclusion that oil shock really affect the GDP growth due to the importance of some customers or firms which their businesses are constantly being affected by this commodity.
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61 Lee mas

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