The role of drains in adolescent idiopathic scoliosis surgery Is it necessary?

Using drains after AIS surgery increases hospital stay duration, blood transfusion rate and patients' anxiety of drain tube removal. Thus, closed suction drainage may not be suitable after AIS surgery

The importance of carotid artery stiffness and increased intimamedia thickness in obese children

Background. Atherosclerosis that starts in childhood invariablyadvances during adulthood.Aim. We aimed to study the effect of obesity on main carotidartery intima-media thickness (CIMT) and arterial stiffness.Material and methods. A total of 78 children were studied fromOctober 2010 to February 2011. They were divided into obese (n=42,group 1) and normal (n=36, group 2). All children were subjectedto physical examination, routine biochemical and haematologicalanalysis, carotid ultrasonography and echocardiographicmeasurements. A detailed medical history was obtained. Bodymass index (BMI) was calculated by dividing participants’ weight inkilograms by the square of their height in metres. Stiffness index âwas calculated using blood pressure and diameter of the systolicand diastolic artery. Intima-media thickness was also measured.Results. The mean age of the obese and normal (control) groupswas 10.12±2.12 years and 9.78±1.78 years, respectively. Weight, BMI,and systolic and diastolic blood pressure values were significantlyhigher in the obese group (all p<0.001). In terms of arterial stiffnessand CIMT measurements, all parameters were higher in the obesegroup than the control (p<0.001). There was a relationship betweenthe degree of obesity and CIMT or stiffness index â. In addition,dilatation and hypertrophy levels in the left ventricle were higherin obese children.Conclusions. Obese children with risk factors for multipleatherosclerosis could have increased CIMT dimensions and,consequently, should be screened for these risks. UltrasonographicCIMT and arterial stiffness measurements can detect vasculardamage at an early stage of development in children withcardiovascular risk factors

Feed rate modeling in circular–circular interpolation discontinuity for high-speed milling

In this paper, a modeling approach is presented in order to evaluate feed rate during a circular interpolation in high-speed milling. The developed model depends on the type of discontinuity and the kinematic performance of the machine tool. To begin with, a feed rate modeling for circular interpolation with continuity in tangency is developed. After, the discontinuity in tangency between two circular interpolations is replaced by discontinuity in curvature by adding a fillet which is in relation to the functional tolerance ε imposed in the part design. An experimental study has been carried out to validate the models

Relationship between retinal sensitivity and disease activity in patients with psoriasis vulgaris

OBJECTIVES: Psoriasis is a hyperproliferative chronic inflammatory skin disease of unknown etiology and ocular structures and visual pathways can also be affected during the course of this disease. Subclinical optic neuritis has previously been observed in psoriatic patients in visual evoked potential studies. This trial was designed to evaluate retinal sensitivity in patients with psoriasis vulgaris. METHODS: A total of 40 eyes of 40 patients with chronic plaque-type psoriasis and 40 eyes of 40 age- and sex-matched control subjects were included in this study. The diagnosis of psoriasis was confirmed by skin biopsy. The severity was determined using the Psoriasis Area and Severity Index and the duration of the disease was recorded. After a full ophthalmological examination, including tests for color vision and pupil reactions, the visual field of each subject was assessed using both standard achromatic perimetry and short wavelength automated perimetry. RESULTS: The mean Psoriasis Area and Severity Index was 22.05±6.40′. There were no significant differences in the visual field parameters of subjects versus controls using either method. There were correlations between disease severity and the mean deviations in standard achromatic perimetry and short wavelength automated perimetry and between disease severity and the corrected pattern standard deviation and pattern standard deviation of short wavelength automated perimetry (r = -0.363, r = -0.399, r = 0.515 and r = 0.369, respectively). CONCLUSIONS: Retinal sensitivity appears to be affected by the severity of psoriasis vulgaris

Development of an oral anticoagulant-use attitude scale, and assessment of its validity and reliability

Conclusions: We found that the OACAs we developed had high reliability and validity

Kinematic modelling of a 3-axis NC machine tool in linear and circular interpolation

Machining time is a major performance criterion when it comes to high-speed machining. CAM software can help in estimating that time for a given strategy. But in practice, CAM-programmed feed rates are rarely achieved, especially where complex surface finishing is concerned. This means that machining time forecasts are often more than one step removed from reality. The reason behind this is that CAM routines do not take either the dynamic performances of the machines or their specific machining tolerances into account. The present article seeks to improve simulation of high-speed NC machine dynamic behaviour and machining time prediction, offering two models. The first contributes through enhanced simulation of three-axis paths in linear and circular interpolation, taking high-speed machine accelerations and jerks into account. The second model allows transition passages between blocks to be integrated in the simulation by adding in a polynomial transition path that caters for the true machining environment tolerances. Models are based on respect for path monitoring. Experimental validation shows the contribution of polynomial modelling of the transition passage due to the absence of a leap in acceleration. Simulation error on the machining time prediction remains below 1%

Mechatronic design, actuator optimization, and control of a long stroke linear nano-positioner

The final publication is available at Elsevier via https://dx.doi.org/10.1016/j.precisioneng.2018.01.007 © 2018. This manuscript version is made available under the CC-BY-NC-ND 4.0 license https://creativecommons.org/licenses/by-nc-nd/4.0/In this paper, mechatronic design, actuator optimization and controls of a long-stroke (20 mm) linear nano-positioner are presented. The mechatronic design is described in terms of the stage's most prominent features regarding mechanical design, assembly, actuator configuration, and power supply. A novel air-bearing/bushing arrangement has been used in which the commonly employed double shaft arrangement is replaced with a single shaft supported by an air bearing from the bottom to constrain the roll motion. The assembly is greatly simplified by exploiting the self-aligning property of the air-bushings which are held in the housings by O-rings. Also, the footprint of the stage is reduced. Voice coil actuators (VCA) in moving magnet mode have been used in complementary double configuration for uniformity of force response. The performance objectives of previously optimized VCA's as standalone actuators are re-evaluated in this configuration. It is observed that while the performance objectives decrease a bit, the desirability of the design point is still retained. Controller design has been made for the current control and position control loops. Heydemann's method for the compensation of encoder quadrature detection errors is implemented. The positioning resolution of the stage as measured from the sensor output is experimentally determined to be +/-5 nm. Dynamic Error Budgeting (DEB) method has been used to analyze the contributing factors to the positioning error, and sensor broadband noise is determined to be the major contributor. The actual positioning accuracy of the stage is estimated by DEB to be 0.682 nm root-mean-square (RMS). The trajectory following accuracy is determined to be +/-15 nm. It is expected that trajectory following accuracy can substantially improve if more advanced compensation methods for encoder quadrature errors are implemented.Natural Sciences and Engineering Research Council of Canada [RGPIN-03879]Engage grant EGP [436910-12

Optimized joint motion planning for redundant industrial robots

The paper presents a model and solution method for optimized robot joint motion planning of redundant industrial robots that execute a set of tasks in a complex work environment, in face of various technological and geometric constraints. The approach aims at directly exploiting redundancy to optimize a given performance measure, e.g., cycle time. Alternative configurations along the path are captured in a graph model, whereas bi-directional transition between task and configuration spaces facilitates generating relevant, collision-free configurations only. Re-parametrization of the trajectory warrants compliance with the robot's kinematic constraints. Successful application of the method is demonstrated in remote laser welding. (C) 2016 CIRP