Effect of Muscle Relaxants on Short-term Results of Exotropia Surgery: A Focus on Resection Procedures

Purpose

We investigated the effect of muscle relaxants (atracurium) on the outcomes of intermittent exotropia surgery under general anesthesia, with a focus on resection procedures.

Methods

Thirty four patients who underwent recession and resection (R&R) were divided into two groups: atracurium usage (group A, n=18) and no atracurium usage (group B, n=16). Patients were divided into two subgroups according to the amount of resection of the medial rectus (MR): less than 5 mm (group 1, n=13) or 5 mm and greater (group 2, n=21). Deviation angles were compared between groups and subgroups. Surgical outcome was defined as successful if distant deviation angles were equal to or less than 10 prism diopters.

Results

The overall postoperative deviation angles did not show statistically significant differences between groups A and B. However, in patients with larger MR resections (≥ 5 mm), the 1 week postoperative distant deviation was significantly larger in group A (1.8±2.6 PD) than in group B (-1.6±4.6 PD, p=0.048 by t-test). The overall undercorrection rate at 3 months postoperatively for group A was 16.7%, which was higher than that of group B (6.3%), and the difference was even larger in subgroups with larger MR resections (≥ 5 mm): 18.2% in group A and 0% in group B.

Conclusions

Patients who underwent R&R procedures under general anesthesia with a muscle relaxant tended to be less corrected than those without muscle relaxant, especially in the early postoperative period and with a larger MR resection equal to or greater than 5 mm. However, there was no significant difference in the later postoperative period.     

Coronary artery lesion distribution in patients with chronic kidney disease undergoing percutaneous coronary intervention

PurposeTo determine the location of coronary atherosclerosis distribution observed in patients with chronic kidney disease (CKD).MethodsA cross-sectional study was conducted using the database of cardiovascular medicine data from Saitama Sekishinkai Hospital to clarify the association between renal function and angiographic characteristics of coronary atherosclerosis. In total, 3268 patients who underwent percutaneous coronary intervention were included. Propensity score matching revised the total to 1772. The association of renal function with the location and/or distribution of coronary atherosclerosis lesions was then examined.ResultsOverall, coronary lesion was observed in the left anterior descending coronary artery (LAD) in 56% patients, whereas 28% and 22% were in the right coronary artery (RCA) and left circumflex coronary artery (LCX), respectively. LAD was most affected and observed in 57% patients with stage 1 CKD. RCA was second-most affected, at 26% CKD stage 1, but it increased to 31%, 38%, and 59% in CKD 3, 4, and 5, respectively. In CKD 5 patients, the RCA was the most affected artery (59%), with 41% LAD lesions. Logistic regression analysis after propensity score matching showed that the odds ratios for an RCA lesion was 3.658 in CKD 5 (p = .025) compared with CKD 1 after adjusting for traditional risk factors.ConclusionThe prevalence of RCA lesions, but not LAD or LCX lesions, increased with increasing CKD stage. The pathophysiology of coronary atherosclerosis may differ by lesion location. Deterioration of renal function may affect progression of atherosclerosis more in the RCA than in the LAD or LCX.     

A Coupled CFD-DEM Study on the Effect of Basset Force Aimed at the Motion of a Single Bubble

The physical meaning of Basset force is first studied via polynomial approximation and the Fourier series representation method. After compiling the Basset force into the coupling interface with Visual C, a dynamic mathematical model is set up to describe the upward motion behavior of a single bubble by adopting the CFD-DEM method. Afterwards, the coupling interface with Basset force proposed in this study is verified experimentally and shows very good agreements. The initial velocity, releasing depth, bubble size, density ratio and viscosity ratio are studied qualitatively due to their great importance to Basset force. The ratio of Basset force to the sum of Basset force and drag force and to buoyancy, F→Ba/(F→D+F→Ba) and |F→Ba/F→B|, are employed to quantify the contribution of Basset force quantitatively. In addition, some instructive outlooks and recommendations on a further development of appropriate and justifiable use of Basset force are highlighted at last.     

Study on the Actuating Performance of an Embedded Macro Fiber Composite Considering the Shear Lag Effect

Macro fiber composite (MFC), which are new ultrathin piezoelectric smart materials, are mostly applied in the fields of shell structure deformation and vibration control. Among others, the application of embedded MFCs in sandwich structures has received wide attention. Currently, its actuating force formula is primarily acquired based on the Bernoulli–Euler Model, which does not consider the shear lag effect and actuating force of MFC ends. To study the actuating performance of an MFC in a sandwich structure, according to its action characteristics, the MFC is divided into upper and lower actuating units without any interaction between to two under the condition of plane strain, and the shear lag effect is considered between the units and the top and bottom of the sandwich structure. The actuating force of the MFC ends is obtained by considering its influence on the bending deformation of the sandwich structure, which deduces the actuating force formula of the embedded MFC. In contrast to ANSYS piezoelectric simulation, the distribution of the MFC interior normal stress is similar to the result from ANSYS piezoelectric simulation, and there is a very small deviation between the MFC end and central normal stress and the result from ANSYS piezoelectric simulation. Taking the end deflection of the sandwich structure with an embedded MFC as an example, the actuating force simulation of the MFC considering the shear lag effect is compared with the ANSYS piezoelectric simulation and actuating force simulation based on the Bernoulli–Euler model. The result indicates that the actuating force simulation of the MFC considering the shear lag effect is closer to the ANSYS piezoelectric simulation, which proves the rationality and necessity of considering the shear lag effect and end actuating force of the MFC.     

A Low-Cost Wireless Bite Force Measurement Device

Assessing maximum voluntary bite force is important to characterize the functional state of the masticatory system. Due to several factors affecting the estimation of the maximum bite force, a unique solution combining desirable features such as reliability, accuracy, precision, usability, and comfort is not available. The aim of the present study was to develop a low-cost bite force measurement device allowing for subject-specific customization, comfortable bite force expression, and reliable force estimation over time. The device was realized using an inexpensive load cell, two 3D printed ergonomic forks hosting reusable subject-specific silicone molds, a read-out system based on a low-cost microcontroller, and a wireless link to a personal computer. A simple model was used to estimate bite force taking into account individual morphology and device placement in the mouth. Measurement reliability, accuracy, and precision were assessed on a calibration dataset. A validation procedure on healthy participants was performed to assess the repeatability of the measurements over multiple repetitions and sessions. A 2% precision and 2% accuracy were achieved on measurements of forces in the physiological range of adult bite forces. Multiple recordings on healthy participants demonstrated good repeatability (coefficient of variation 11%) with no significant effect of repetition and session. The novel device provides an affordable and reliable solution for assessing maximum bite force that can be easily used to perform clinical evaluations in single sessions or in longitudinal studies.     

Experimental Investigation of the Tensile Behavior of Selected Tire Cords Using Novel Testing Equipment

Aramid and polyamide cords are used in a wide range of applications, particularly in the automotive industry (tire reinforcement) and textile industry for military and fireguard purposes. The problem of the reliable experimental study of tensile behavior of synthetic cords is considered in this paper. In the available standards for synthetic cord testing, particularly ASTM D 885-03, the tensile test must result with the cord damage in the middle of gauge length, and the cords should be fixed in the machine clamps. The trial test gave damage near the clamps. We propose a novel testing stage mounted in the testing machine clamps to achieve the uniform tensile stress distribution in the gauge length of the measured cords. The results of the deformations were measured in two ways: using testing machine head displacement and a videoextensometer. Stress curves of four distinguished cords were evaluated and compared. The second method allowed to acquire results differing from the manufacturers’ data from 0.7% to 21.5%, which allowed for the conclusion that the designed test stand allows for obtaining reliable results for stretched cords.     

Study on Milling Force and Surface Quality during Slot Milling of Plain-Woven CFRP with PCD Tools

Carbon-fiber-reinforced polymers (CFRPs) have been widely used in many industrial fields, such as automobile, aerospace and so on, because of their excellent mechanical properties. However, due to their anisotropy and inhomogeneity, machining CFRPs is a great challenge. In this paper, the slot milling of a plain-woven CFRP with PCD tools is carried out, and the effects of cutting parameters and tool rake angle on cutting force and surface roughness are studied. The results show that the 4° rake angle PCD tool has smaller cutting force than the 0° rake angle PCD tool, but the effect of rake angle on surface roughness is not significant. The concept of equivalent cutting area is introduced to study the variation law of cutting force and surface roughness. It is found that the cutting force and surface roughness increase with the increase in equivalent cutting area, and decrease with the decrease in equivalent cutting area. The removal mechanism of surface materials under different equivalent cutting areas is different, which leads to the difference in surface roughness. Finally, the causes of delamination on the top layer after milling are explained.     

反油酸对人脐静脉平滑肌细胞活力的影响

<正>平滑肌细胞是血管壁中膜的主要细胞成分,是动脉粥样硬化(atherosclerosis,As)和血管成形术后再狭窄(restenosis after angioplasty,RAA)等病理过程形成和发展的重要部位,对血管壁的完整性和紧张性的调节也起重要作用,其异常增殖及形态学转变将导致动脉粥样硬化过程     

Analytical Model for Early Design Stage of Cable-Stayed Suspension Bridges Based on Hellinger–Reissner Variational Method

The cable-stayed suspension bridge is one type of bridge that has been increasingly applied to bridge engineering, especially in cross-sea projects. However, the complex combined system of this type of bridge makes it quite difficult for researchers to make a quick decision of the parameter values during the design stage. The Hellinger–Reissner method is applied here to analyze the deformation and force of the structural members in the bridge. The advantage of this method is that the solving of deformation and force is independent of each other, which would enhance the accuracy of the final results. Different load conditions are also considered in the analysis. The results from the present method are compared with test results and finite element analysis, and show good agreements. It implies that the Hellinger–Reissner is a comparatively more efficient method to help designers choose the key parameters for cable-stayed suspension bridges.