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The present study aimed to evaluate the rate of positive surgical margins for magnetic resonance imaging (MRI) performed in the supine position prior to breast-conserving surgery (BCS). The rate of positive surgical margins and the clinicopathological factors were examined in consecutive patients with BCS who underwent preoperative MRI performed in the supine position at Sapporo Medical University Hospital (Sapporo, Japan) and related hospitals and clinics between January 2012 and December 2013. Of 1,175 eligible patients, 1,150 were included after excluding 25 patients with either bilateral breast cancer or stage IV disease. Positive margin was defined as no cancer seen on the resected margin. The primary endpoint was the rate of positive surgical margins when preoperative MRI was performed in the supine position and the secondary endpoint was identification of the factors that predict positive margins. Of the 1,150 female patients (median age, 55 years; range, 29-97 years) who underwent BCS for breast cancer following MRI performed in the supine position, 215 (18.8%) had positive margins, which is similar to the rate with MRI in the prone position, and 930 (81.2%) had negative margins. The rate of positive surgical margins in patients of the human epidermal growth factor receptor 2 (HER2) type was significantly higher than that in the non-HER2 type group (6.5 and 2.9%; χ(2) P=0.0103). There was no increase in the rate of positive margins in breast cancers with a diameter of >T2. The rate of positive surgical margins following MRI performed in the supine position was 18.8%. Supine MRI appears to be suitable for informing on the extent of resection of breast cancer.

This study examined the residual stresses on the surface and in the interior of a deep-drawn cup made from a 1180-MPa class ultra-high strength steel sheet. A high residual stress causes a delayed material fracture, and an accurate evaluation of residual stress reduces failure risks. Nevertheless, the residual stress in the vicinity of the scratch marks, induced by galling in the stamping process, remains unclear. This study accordingly presented X-ray diffraction measurements of the considerable residual compressive stress associated with the scratch marks. Measurements obtained using the hole drilling method revealed a previously unknown high residual tensile stress (exceeding 1000 MPa) in the interior at the scratch mark locations, corresponding to a 0.1-mm-thick compressive zone. These measurements were then compared with the results of a finite element (FE) simulation of the deep drawing process performed without the formation of the scratch marks; the simulated residual stress in the scratch mark region considerably deviated from the measurements. A compressive stress of approximately 1000 MPa was therefore imposed on the local surface area to account for the formation of the scratch marks. The prediction of the actual residual stress on the surface and in the interior of the scratch mark region was then discussed. A simple surface stress modification technique for scratch mark prediction was realized from the comparison between the measured and FE simulation results. The stored friction work, modified by the equivalent plastic strain induced by deep drawing, could be adopted to accurately predict the location of the scratch mark region.

In this work, non-uniform deformation behavior of coarse-grained ultralow carbon steel was investigated under uniaxial tension and cyclic simple shear. A digital image correlation method was used to measure strain fields at the grain level. Heterogeneous strain distribution appeared at the early stage of the process, and the heterogeneity remained almost unchanged in the subsequent deformation. Localized strain bands were observed under both uniaxial tension and simple shear, but the directions of the bands were different between the two deformation modes. It was hypothesized that the directions of the strain bands were correlated with the planes where the maximum or minimum shear stresses occurred. During cyclic simple shear, the heterogeneity of strain distribution and occurrence of strain bands depended on the shear direction. In contrast, the number of cycles had little effect on the heterogeneity of strain distribution. Comparing the grain boundaries and the strain distributions, it was observed that many of the strain-band boundaries occurred along the grain boundaries, but some of them appeared within grains.

Transformation induced plasticity (TRIP) steels present a remarkable balance of strength and ductility. However, their post-necking hardening behavior, which is required for press-forming and autom...

Background Rocuronium consumption with or without intraoperative objective neuromuscular monitoring in clinical settings of unrestricted use of sugammadex and neuromuscular monitoring has not been reported earlier. The study aimed to investigate the association between the use of intraoperative objective neuromuscular monitoring and rocuronium consumption in patients undergoing laparoscopic abdominal surgery. Methods Data were collected by reviewing electronic medical records of patients who received laparoscopic abdominal surgery under general anesthesia with rocuronium and reversal with sugammadex at a university teaching hospital between May 2017 and April 2018. A multivariate linear regression model was developed to compare the amount of rocuronium consumption (mg) per weight (kg) per hour (mg/kg/h) between the group in which intraoperative objective neuromuscular monitoring was used (NMM+ group) and the group in which intraoperative neuromuscular monitoring was not used (NMM− group). Additionally, we performed an interaction test. Results A total of 429 patients were evaluated, with 371 patients (86%) included in the NMM+ group and 58 patients (14%) in the NMM− group. Log-transformed rocuronium consumption between the NMM+ group and NMM− group was not significantly different (back-transformed β coefficients [95% CI]: 1.080 [0.951-1.226]; P = 0.23). Male sex and body mass index (BMI) were independent factors associated with 15% (0.853 [0.788-0.924]; P < 0.001) and 3% (for every 1 kg/m2 increase in BMI) (0.971 [0.963-0.979]; P < 0.001) decrease in intraoperative rocuronium consumption, respectively. A significant interaction was detected only between the use of neuromuscular monitoring and age ≥65 years (β: 0.803 [0.662-0.974]; P = 0.026). Conclusions Although the use of intraoperative objective neuromuscular monitoring was not an individual factor influencing intraoperative rocuronium consumption, this retrospective study demonstrated that the use of intraoperative neuromuscular monitoring reduced rocuronium consumption for approximately 20% of elderly patients (age ≥65 years) undergoing laparoscopic abdominal surgery.

Background: Rocuronium consumption with or without intraoperative objective neuromuscular monitoring in clinical settings of unrestricted use of sugammadex and neuromuscular monitoring has not been reported. The aim of the study was to investigate the association between the use of intraoperative objective neuromuscular monitoring and rocuronium consumption in patients undergoing laparoscopic abdominal surgery.Methods: Data were collected by reviewing electronic medical records of patients who received laparoscopic abdominal surgery under general anesthesia with rocuronium and reversal with sugammadex at Asahikawa Medical University Hospital between May 2017 and April 2018. Multiple linear regression model was developed to compare the amount of rocuronium consumption per weight per hour (mg/kg/h) between the group in which intraoperative objective neuromuscular monitoring was used (NM+ group) and the group in which intraoperative neuromuscular monitoring was not used (NM- group). Additionally, we performed an interaction test with reference to the results of the subgroup analysis.Results: A total of 429 patients were evaluated, with 371 patients (86%) included in NM+ group and 58 patients (14%) in NM- group. In the NM+ group, 94% of the patients received additional rocuronium after reappearance of TOF response while 6% of the patients received additional rocuronium before reappearance of TOF in order to maintain post-tetanic count. Log-transformed rocuronium consumption between NM+ group and NM- group was not significantly different (back-transformed β-coefficients [95%CI]: 1.054 [0.946–1.174]; P=0.34). Male sex and body mass index (BMI) were independent factors associated with 15% (0.854 [0.789–0.925]; P2 increase in BMI) (0.970 [0.962­–0.979]; Pβ: 0.843 [0.759–0.936]; P=0.001).Conclusions: This single center retrospective study demonstrated that although the use of intraoperative objective neuromuscular monitoring was not an individual factor influencing intraoperative rocuronium consumption, the use of intraoperative neuromuscular monitoring reduced rocuronium consumption by approximately 15% during laparoscopic abdominal surgery in elderly patients.

This study identified the work-hardening parameters and fracture strain of a hardened die-steel (SKD11). Herein, a shear punching test was used as the low stress-triaxiality suppresses material fracture due to the brittle behavior of SKD11 in tensile tests. Furthermore, a minute punch-die clearance was used to increase the compression stress due to the material deformation. SKD11 steel sheets of 1.0 mm thickness were successfully deformed, and the punching force as well as stroke were recorded for inverse analysis using the finite element analysis (FEA). Subsequently, FEA of the shear punching test was repeated to optimize the parameters of Swift’s work-hardening law. Consequently, the Swift parameters were derived to ensure that the measured values of the punching force and stroke correspond with the numerically simulated curve. The fracture strain was identified as the maximum equivalent plastic strain at the punch stroke of specimen rupture.

The study examines the control algorithm of a three-dimensional attitude and position of a free-floating rigid body with three thruster forces in which the force directions are fixed with respect to the body. This study provides a theory to develop a control method of an underactuated satellite with the minimum thruster number. In the procedure, three switching controllers are used in conjunction with motion planning in the final angular-rate deceleration phase to individually control the six state variables to the target values. The switching controllers have a hierarchical structure by using invariant manifolds as switching surfaces. The state variables in higher class manifolds that include lower class ones are adjusted by repeatedly adding intentional disturbances while the lower class state variables are returned to the original values by using lower class invariant manifolds. This study describes methods to define the invariant manifolds and also the intentional disturbance for achieving the forementioned control strategy. Finally, the motion planning in the angular-rate deceleration phase from a remained single-axis rotation finalizes the six state values of the body to the target values. Numerical simulations verify the proposed method.

This paper evaluates fracture strains of two types of 590 MPa-class steel sheets, JSC590Y and JSC590R with the thickness of 1.2 mm. Small circular-rod specimens with the minimum diameter of 1.0 mm in the gauge region were tensioned under hydrostatic pressures of 200 and 400 MPa for this evaluation. Time histories of minimum diameter were measured and then converted to true strain histories. The tensile tests revealed different fracture strain behavior due to hydrostatic pressures in the two steel sheets: JSC590R showed an increase in fracture strains at high hydrostatic pressures, but JSC590Y presented almost consistent fracture strains for all tested pressures.

This study described the effect of mechanical properties on the roundness of a drilled hole in the drilling of low-rigidity workpieces. A thin-thickness part workpiece model involving a beam plate structure fixed on both ends was used in the study. The effects of feed, workpiece length, distance from the fixed end to the drilling point, and mechanical properties of the workpiece on the roundness of the hole were investigated. The thrust force increased with feed and the roundness became worse with feed. The hole was enlarged in the longitudinal direction of the workpiece at the upper section of the hole. An increase in the workpiece length decreased the rigidity of the workpiece and deteriorated the roundness of the hole. The roundness error was extremely small when the drilling point was near the fixed end. Carbon steel, aluminum alloy, stainless steel, and titanium alloy were used as workpiece materials. The thrust force in the drilling of titanium alloy and stainless steel was considerably larger than that of the carbon steel and aluminum alloy. The roundness of the hole was worse in the drilling of titanium alloy and stainless steel than that in the drilling of carbon steel and aluminum alloy. Plastic deformation occurred in the workpieces made of titanium alloy and stainless steel, which is probably because the workpiece was yielded by the large thrust force. The value of the ratio of the thrust force in drilling to the Young’s modulus of the workpiece was used in evaluating the deflection of the workpiece and the roundness error of the hole in drilling.

Tri-electrode plasma actuator (TED-PA), which has a third electrode with DC high voltage, can generate stronger jet than that of conventional two-electrode plasma actuator. However, the behavior of...

This study investigated the effect of using a rooftop piercing punch on the hole-expansion ratio of high-strength steels. The holes made using the piercing punch showed very high hole-expansion ratios under certain conditions. Regarding the rooftop-vertical angles, the hole-expansion ratio increased at 80° and decreased at 45°. The sheet bending effect caused by the rooftop shape contributed to these results. The small amount of bending in the case of 80° induced tensile stress around the punch edge without plastic deformation, which accelerated the material fracture. This acceleration decreased the plastic strain on the pierced surface and led to a high hole-expansion ratio. In the case of 45°, a large amount of bending caused plastic deformation around the punch edge, which deteriorated the hole-expansion ratio. Regarding the material direction when set on a die face, the hole-expansion ratio increased when the material direction with the highest ductility on the pierced surface was at 90° to the rooftop line. In this condition, the ductility at the weakest position on the pierced surface resulting from piercing using the rooftop punch reaches a maximum in the other material directions.

Submicron crystallization suppresses hydrogen-induced delayed cracking on hot-sheared surfaces, which are formed during a hot-stamping process. To gain insights into the mechanism of this suppression, in this study, detailed microstructural characterization in the vicinity of the hot-sheared surface was performed. A hot-halfway-cut test, which consists of punch penetration into an austenitized hot specimen followed by water quenching, was conducted for this characterization. This test provided information about the microstructural evolution with respect to equivalent plastic strain by controlling punch penetration. Furthermore, the microstructural analyses were straightforward because this test did not involve the difficult complication of accounting for material fracture during the hot shearing. For this test, a finite element simulation was used to evaluate the strain distribution in the hot-deformed zone. Optical observations and hardness measurements clarified that at 750 °C, the microstructure that covers the hot-sheared surface starts to transform when the equivalent plastic strain is greater than approximately 1.0. In addition, scanning electron microscopy, electron backscatter diffraction analysis, electron probe microanalysis, and transmission electron microscopy revealed the following microstructural details: In the vicinity of the burnished part of the hot-sheared surface, the microstructure is composed mostly of ferrite that contains banded carbides and has grain sizes on the order of 0.4–0.6 μm, rather than bainite or martensite. On the other hand, in the vicinity of the fractured part, the microstructure is composed of ferrite and banded bainite, and has grain sizes on the order of 0.6–2 μm.