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This study investigated a time-domain method that uses a neural network (NN) to identify three linear parameters such as mass, viscous damping coefficient and spring constant, as well as nonlinear forces of a nonlinear vibration system. In this method, the measured excitation force, acceleration, velocity, and displacement are input to the NN, which learns the force equilibrium between the external force, inertial force, damping force, and nonlinear restoring force, thus identifying the characteristics of the vibration system in an explicit manner. The proposed NN consists of two subnetworks: the linear subnetwork and the nonlinear subnetwork. The nonlinear subnetwork is called a global NN and cooperates with a local NN that extracts linear parameters. The features of the proposed method are: I) linear parameters are intentionally extracted based on the equation of motion, and II) guidelines for setting hyperparameters can be obtained from the behavior of the mean squared error (MSE). In this study, numerical simulations for parameter identification were performed to validate the proposed identification method. The vibration systems investigated were those governed by the Duffing and Van der Pol equations, as well as those in which the restoring force is represented by a sine function. The data obtained by numerically solving the equations of motion were considered as experimental data, and the linear parameters and nonlinear forces were identified to confirm the validity and applicability of the proposed method.

Abstract Background Image-sharpening algorithms with color adjustments enable real-time processing of the surgical field with a delay of 4 msec for heads-up surgery using digital three-dimensional displays. The aim of this study was to investigate the usefulness of the algorithms with the Artevo 800® digital microscope. Methods Seven vitreoretinal surgeons evaluated the effects of image-sharpening processing on the clarity of the surgical field with the Artevo 800® system that is used for cataract and vitreous surgeries. The scorings were made on a 10-point scale for anterior capsulotomy, phacoemulsification, cortex aspiration, core vitrectomy, and peeling of an epiretinal membrane or an internal limiting membrane. In addition, the images during the internal limiting membrane peeling were processed with or without color adjustments. We also evaluated the skewness (asymmetry in the distribution of the pixels) and kurtosis (sharpness in the distribution of the pixel) of the images to evaluate the contrast with each intensity of image-sharpening. Results Our results showed that the mean visibility score increased significantly from 4.9 ± 0.5 at 0% (original image) to 6.6 ± 0.5 at 25% intensity of the image-sharpening algorithm (P

Abstract We conducted clinical and experimental studies to investigate the effects of image-sharpening algorithms and color adjustments, which enabled real-time processing of live surgical images with a delay of 0.004 s. The images were processed with image-sharpening intensities of 0%, 12.5%, 25%, and 50% during cataract surgery, vitrectomy, peeling of epiretinal membrane, and peeling of internal limiting membrane (ILM) with the Ngenuity 3D visualization system. In addition, the images obtained with a yellow filter during the ILM peeling were processed with color adjustments. Five vitreoretinal surgeons scored the clarity of the images on a 10-point scale. The images of a 1951 United States Air Force grating target placed in no fluid (control), saline, and 0.1% and 1% milk solution were evaluated. The results showed that the mean visibility score increased significantly from 5.0 ± 0.6 at 0% to 6.4 ± 0.6 at 12.5%, 7.3 ± 0.7 at 25%, and 7.5 ± 0.9 at 50% (P

Background The aim of this study was to compare the predictive accuracy of acute kidney injury (AKI) after cardiac surgery using cardiopulmonary bypass for the largest area under the curve (AUC) below the oxygen delivery (DO2) threshold and the cumulative AUC below the DO2 threshold. Methods and Results From March 2017 to October 2019, 202 patients who had undergone cardiac surgery with cardiopulmonary bypass were enrolled. The perfusion parameters were recorded every 20 seconds, and the DO2 (10×pump flow index [L/min per m2]×[hemoglobin (g/dL)×1.36×arterial oxygen saturation (%)+partial pressure of arterial oxygen (mm Hg)×0.003]) threshold of 300 mL/min per m2 was considered to define sufficient DO2. The nadir DO2, the cumulative AUC below the [Graphic: see text], and the largest AUC below the [Graphic: see text] were used to predict the incidence of AKI. Postoperative AKI was observed in 12.4% of patients (25/202). By multivariable analysis, the largest AUC below the [Graphic: see text] ≥880 (odds ratio [OR], 4.9; 95% CI, 1.2–21.5 [P=0.022]), preoperative hemoglobin concentration ≤11.6 g/dL (OR, 7.6; 95% CI, 2.0–32.3 [P=0.004]), and red blood cell transfusions during cardiopulmonary bypass ≥2 U (OR, 3.3; 95% CI, 1.0–11.1 [P=0.041]) were detected as independent risk factors for AKI. Receiver operating curve analysis revealed that the largest AUC below the [Graphic: see text] was more accurate to predict postoperative AKI compared with the nadir DO2 and the cumulative AUC below the [Graphic: see text] (differences between areas, 0.0691 [P=0.006] and 0.0395 [P=0.001]). Conclusions These data suggest that a high AUC below the [Graphic: see text] is an important independent risk factor for AKI after cardiopulmonary bypass, which could be considered for risk prediction models of AKI.

Objective: The aim of this study was to describe laparoscopic anatomical parenchymal sparing liver resections for hepatocellular carcinoma (HCC) and colorectal liver metastases (CRLM) and report the short-term outcomes. Background: Anatomical resections (ARs) have better oncological outcomes compared to partial resections in patients with HCC, and some suggest should be performed also for CRLM as micrometastasis occurs through the intrahepatic structures. Furthermore, remnant liver ischemia after partial resections has been associated with worse oncological outcomes. Few experiences on laparoscopic anatomical resections have been reported and no data on limited AR exist. Methods: We performed a retrospective analysis of 86 patients undergoing full laparoscopic anatomical parenchymal sparing resections with preoperative surgical simulation and standardized procedures. Results: A total of 55 patients had HCC, whereas 31 had CRLM with a median of 1 lesion and a size of 30 mm. During preoperative three-dimensional (3D) simulation, a median resection volume of 120 mL was planned. Sixteen anatomical subsegmentectomies, 56 segmentectomies, and 14 sectionectomies were performed. Concordance between preoperative 3D simulation and intraoperative resection was 98.7%. Two patients were converted, and 7 patients experienced complications. Subsegmentectomies had comparable blood loss (166 mL, P = 0.59), but longer operative time (426 min, P = 0.01) than segmentectomies (blood loss 222 mL; operative time 355 min) and sectionectomies (blood loss 120 mL; operative time 295 min). R0 resection and margin width remained comparable among groups. Conclusions: A precise preoperative planning and a standardized surgical technique allow to pursue the oncological quality of AR enhancing the safety of the parenchyma sparing principle, reducing surgical stress through a laparoscopic approach. [ABSTRACT FROM AUTHOR]

The aim of this study was clarify the effects of reducing various functional pressures essential for the maintenance of bone homeostasis. Femoral bone mineral density (BMD) and biological apatite (BAp) crystallite alignment were measured in conventionally reared and hindlimb-unloaded mice. The femur was divided into 10 equal segments perpendicular to the longitudinal axis of the bone and measurements were performed on the cortical bone in the five segments closest to the midpoint of the femur. Significantly lower BMD and BAp alignment in the longitudinal (Z-axis) direction were observed in the hindlimb-unloaded group. The present findings suggest that unloading by tail suspension significantly decreases not only mouse femoral bone mass but also BAp crystallite alignment, although minimal uniaxial preferential alignment is retained. [ABSTRACT FROM AUTHOR]

OBJECTIVES: Re-expansion pulmonary oedema (RPO) sometimes occurs after minimally invasive cardiac surgery (MICS) with single-lung ventilation. However, it has not been widely recognized as a serious complication. The aim of this study is to evaluate the occurrence rate and risk factors of RPO. METHODS: A total of 381 consecutive patients who underwent MICS with right mini-thoracotomy from March 2005 to October 2013 were retrospectively reviewed. RESULTS: RPO was observed in 8 (2.1%) patients. In the preoperative data, greater percentages of preoperative use of steroid or immunosuppressant were found in patients with RPO (25% [2/8] vs 1% [4/373]; P = 0.0056). In the operative data, significantly longer operation, cardiopulmonary bypass (CPB) and aortic cross-clamping (ACC) times as well as greater percentages of second CPB run were found in patients with RPO (388 ± 80 vs 272 ± 61 min; P < 0.0002, 253 ± 79 vs 158 ± 50 min; P = 0.0009, 162 ± 65 vs 108 ± 38 min; P = 0.020 and 38% [3/8] vs 1.3% [5/373]; P < 0.0003). The overall 30-day mortality rate was 0.8% (3/381) and the 30-day mortality rate of patients with RPO was 12.5% (1/8). Significantly prolonged initial ventilation time, intensive care unit and postoperative hospital stay were observed in patients with RPO (P = 0.0022, <0.0001 and 0.0003, respectively). Multivariate logistic analysis detected preoperative use of steroid or immunosuppressant and prolonged ACC time (≥156 min) as independent risk factors for RPO after MICS (odds ratio [OR]: 87.6 [95% confidence interval, CI: 4.1–2463.8]; P = 0.006 and OR: 36.0 [95% CI: 4.8–731.4]; P < 0.001). CONCLUSIONS: RPO should be recognized as one of the most serious complications after MICS with right mini-thoracotomy. More accurate risk factors of prolonged lung malperfusion and steroid use on RPO after MICS should be investigated. [ABSTRACT FROM AUTHOR]

Objective Right axillary artery (RAxA) perfusion was introduced for selective antegrade cerebral perfusion in total aortic arch repair to prevent cerebral embolism derived from arterial cannulation. However, the strategic benefits and long-term results regarding the cannulation site remain controversial. We retrospectively compared the outcomes between propensity score-matched patients with and without using RAxA cannulation. Methods Between 2006 and 2012, 260 consecutive patients underwent total arch repair with antegrade cerebral perfusion and moderate hypothermia at a single institution. RAxA cannulation was added in 142 patients (54.6%), and 70 propensity score-matched pairs were obtained. Results There were no significant differences in 30-day (2.9% [2 of 70] vs 5.7% [4 of 70]; P = .415 and in-hospital death (5.7% [4 of 70] vs 5.7% [4 of 70]; P = 1.000) between matched pairs. Although there was no significant difference in the occurrence of postoperative stroke (8.6% [6 of 70] vs 8.6% [6 of 70]; P = 1.000), the new rate of new occurrence of postoperative paraparesis was lower in patients with RAxA perfusion (0% [0 of 70] vs 4.3% [3 of 70]; P = .067). With a mean follow-up period of 1057 ± 686 days, the overall 5-year survival was 90.6% and was 89.6% for patients with RAxA perfusion. Thee difference in survival between patients with and without RAxA perfusion was not significant. Conclusions RAxA perfusion is a useful option for total aortic arch repair, and the midterm outcomes were satisfactory. However, RAxA perfusion did not completely prevent stroke in patients with an atherothrombotic aorta. [ABSTRACT FROM AUTHOR]