Intraoperative Hypotension Prediction Based on Features Automatically Generated Within an Interpretable Deep Learning Model.

The monitoring of arterial blood pressure (ABP) in anesthetized patients is crucial for preventing hypotension, which can lead to adverse clinical outcomes. Several efforts have been devoted to develop artificial intelligence-based hypotension prediction indices. However, the use of such indices is limited because they may not provide a compelling interpretation of the association between the predictors and hypotension. Herein, an interpretable deep learning model is developed that forecasts hypotension occurrence 10 min before a given 90-s ABP record. Internal and external validations of the model performance show the area under the receiver operating characteristic curves of 0.9145 and 0.9035, respectively. Furthermore, the hypotension prediction mechanism can be physiologically interpreted using the predictors automatically generated from the proposed model for representing ABP trends. Finally, the applicability of a deep learning model with high accuracy is demonstrated, thus providing an interpretation of the association between ABP trends and hypotension in clinical practice.

Crash Performance of Strength Gradient Tube Induced by Selective Laser Patterning.

This paper presents an investigation of the performance of a 22 MnB5 tube after local heat treatment according to a patterning shape under dynamic crash test conditions to propose the patterning shape with the best energy absorption efficiency. Numerical simulations support experimental results to validate the deformation mode during dynamic crash test as well as the strain distribution of the specimen. The helical patterning not only demonstrates the highest axial loading force and energy absorbance in both static and dynamic crash tests, but also can be easily fabricated in a short time. The helical pattern can optimize different pitch sizes according to the thickness and diameter of the cylindrical tube, and it has the highest energy absorption rate with 83.0% in dynamic conditions.

Microstructural Control Strategy Based on Optimizing Laser Powder Bed Fusion for Different Hastelloy X Powder Size.

In additive manufacturing (AM), the powder properties and laser powder bed fusion (LPBF) process parameters influence the quality of materials and building parts. However, the relationship between the size of the powder, LPBF process parameters, and mechanical properties is not well-established. In addition, Hastelloy X (HX) is attracting attention for its excellent high-temperature properties, but it is difficult to process, such as by cutting and milling, because of its high hardness and high ductility. This can be overcome by applying the AM process. We compared the LPBF window process maps for two HX powders of different sizes. Despite their small difference of 19.7% in particle size, it was confirmed that the difference in laser power was more than 40 W, the difference in scan speed was more than 100 mm/s, and the difference in energy density was more than 20% under the optimal process conditions. The as-built specimen had a larger molten-pool size as the energy density was higher, which resulted in the differences in mechanical properties at room temperature and high temperature (816 °C). We considered the control of the size of the powder to obtain the properties required for each temperature condition. The microstructures and mechanical properties of the as-built LPBF specimens were also investigated and compared with those of cast HX. Because of the rapid melting and solidification processes in LPBF, the as-built HX exhibited nano-sized dendrite structures and large internal strain energy. This resulted in the as-built LPBF exhibiting a higher room-temperature tensile strength than the cast material. Under high-temperature conditions, the grain boundary of the as-built LPBF acts as a sliding path, and the as-built LPBF HX showed significantly better high-temperature tensile strength characteristics than the cast HX.

Laboratory and field study on changes in water quality and increase in dissolved iron during riverbank filtration.

Changes in the water quality by the riverbank filtration (RBF) process were investigated in the field-scale demonstration sites. The overall water quality was improved by RBF, but Fe2+ concentration significantly increased in the riverbank-filtered water more than in the river water. This result would be caused by the interaction between the iron minerals and the river water in the aquifer and the influx of the hinterland groundwater into RBF wells. Dissolution properties of iron from the aquifer soils cored at the sites were evaluated through incubation experiment considering various values of redox potential (Eh), dissolved oxygen (DO), and hydrogen-ion concentration exponent (pH). These results presented that at the incubator with the final Eh of 470 mV, DO of 3.4, and pH of 4.53, the iron from the aquifer soil was most dissolved, and the pyrite and siderite contents in the aquifer soil decreased significantly from 11.5 to 6.22% and from 50.8 to 24.5%, respectively. Based on changes of ion concentrations (such as Fe2+, Fe3+, SO42- and NO3-) and iron species in the incubators, it was believed that pyrite and siderite minerals in the aquifer soils cause an increase in the Fe2+ concentration with the absence of DO and an increase in the Fe2+ and Fe3+ concentrations with the presence of DO. The dissolution rates of iron minerals into Fe2+ and Fe3+ were dependent on Eh, pH, and DO and were more sensitive to Eh and pH than DO. The results of this study can provide information on RBF site selection and its operation.

Protective effects of pine bark extract against cisplatin-induced hepatotoxicity and oxidative stress in rats.

We investigated the protective effects of pine bark extract (pycnogenol®, PYC) against cisplatin-induced hepatotoxicity and oxidative stress in rats. Twenty-four male rats were divided into the following four groups: (1) vehicle control, (2) cisplatin (7.5 mg/kg), (3) cisplatin & PYC 10 (10 mg/kg/day), and (4) cisplatin & PYC 20 (20 mg/kg/day). A single intraperitoneal injection of cisplatin induced hepatotoxicity, as evidenced by an increase in serum aminotransferase and histopathological alterations, including degeneration/necrosis of hepatocytes, vacuolation, and sinusoidal dilation. In addition, an increase in the malondialdehyde (MDA) concentration and a decrease in the reduced glutathione (GSH) content and catalase (CAT), superoxide dismutase (SOD), and glutathione S-transferase (GST) activities were observed in the cisplatin-treated rat hepatic tissues. In contrast, PYC treatment effectively prevented cisplatin-induced hepatotoxicity, including the elevation of aminotransferase and histopathological lesions, in a dosedependent manner. Moreover, PYC treatment also induced antioxidant activity by decreasing MDA level and increasing GSH content and SOD and GST activities in liver tissues. These results indicate that PYC has a protective effect against acute hepatotoxicity induced by cisplatin in rats, and that the protective effects of PYC may be due to inhibiting lipid peroxidation and increasing antioxidant activity.

Touch print cytology shows higher sensitivity than pleural lavage cytology for pleural micro-metastasis in lung cancer.

Many authors have used pleural lavage cytology for confirming pleural micro-metastasis in lung cancer, but the results showed relatively low sensitivity having positive range of 4-14%. So, if we have a method with higher sensitivity than lavage cytology, the significance of pleural micro-metastasis will be elucidated clearly. To detect micro-metastasis, we underwent touch print cytology using glass slides and lavage cytology. Just after thoracotomy, touch print was carried with 2 pieces of glass slide from the visceral pleural surface of tumor mass. Then, two lavage cytology were collected at the times of pre-resection and post-resection (after distilled water irrigation) using each 1 liter of saline. The glass slides and lavages were examined for confirming micro-metastasis of cancer cells. From June 1998 to May 2004, 146 tumor masses of lung cancer have been subjected. Among them, 127 sets of cytology slides were reviewed completely in the last one month. Touch print cytology was found to be positive in 81.9% (104/127), while lavage cytology in 4.7% (6/127) of pre-resection and in 0.8% (1/127) of post-resection. To detect pleural micro-metastasis, touch print cytology using a glass slide can be considered as an easy and effective method having higher sensitivity than lavage cytology.

Feasibility of latissimus dorsi and serratus anterior muscle-sparing vertical thoracotomy in general thoracic surgery.

Postero-lateral thoracotomy has many complications such as postoperative pain, limitation in the motion of the shoulder, decreasing pulmonary function from immobilization, increasing lung atelectasis from over-use of analgesia, and increasing pulmonary morbidity, especially in elderly patients. So, muscle-sparing thoracotomy appears to be a good alternative. But it has also many disadvantages such as seroma and the needs for drains, limitation of an accessible operative field, and difficulties with risky procedures. We have modified muscle-sparing vertical thoracotomy. We performed 134 procedures on 131 patients from October 2000 to September 2003, including 15 cases of esophageal cancer, 95 cases of lung cancer, and 24 cases of other disease. Operative procedures were lobectomy in 74 cases, bilobectomy in 12 cases, pneumonectomy in 10 cases, wedge resection in 8 cases, decortication in 2 cases, Ivor Lewis procedure in 13 cases, and others in 15 cases. There was no occurrence of wound infection, arrrhythmia, fibrillation, and subcutaneous seroma except the first two cases. We had seven reoperations (two postoperative bleeding, three postpoperative BPF, one EGstomy leak, one RML torsion) and four operative mortalities (one postpneumonectomy BPF, two pneumonia, one heart failure). Our muscle-sparing vertical thoracotomy can be done safely in most thoracic surgery including lung and esophageal cancer, therefore it is a feasible procedure.