Search

Purpose: Countertraction is a vital technique in laparoscopic surgery, stretching the tissue surface for incision and dissection. Due to the technical challenges and frequency of countertraction, autonomous countertraction has the potential to significantly reduce surgeons' workload. Despite several methods proposed for automation, achieving optimal tissue visibility and tension for incision remains unrealized. Therefore, we propose a method for autonomous countertraction that enhances tissue surface planarity and visibility., Methods: We constructed a neural network that integrates a point cloud convolutional neural network (CNN) with a deep reinforcement learning (RL) model. This network continuously controls the forceps position based on the surface shape observed by a camera and the forceps position. RL is conducted in a physical simulation environment, with verification experiments performed in both simulation and phantom environments. The evaluation was performed based on plane error, representing the average distance between the tissue surface and its least-squares plane, and angle error, indicating the angle between the tissue surface vector and the camera's optical axis vector., Results: The plane error decreased under all conditions both simulation and phantom environments, with 93.3% of case showing a reduction in angle error. In simulations, the plane error decreased from 3.6 ± 1.5 mm to 1.1 ± 1.8 mm , and the angle error from 29 ± 19 ∘ to 14 ± 13 ∘ . In the phantom environment, the plane error decreased from 0.96 ± 0.24 mm to 0.39 ± 0.23 mm , and the angle error from 32 ± 29 ∘ to 17 ± 20 ∘ ., Conclusion: The proposed neural network was validated in both simulation and phantom experimental settings, confirming that traction control improved tissue planarity and visibility. These results demonstrate the feasibility of automating countertraction using the proposed model., (© 2024. The Author(s).)

Though the complementary power field effect transistors (FETs), e.g., metal-oxide-semiconductor-FETs (MOSFETs) based on wide bandgap materials, enable low switching losses and on-resistance, p-channel FETs are not feasible in any wide bandgap material other than diamond. In this paper, we propose the first work to investigate the impact of fixed positive surface charge density on achieving normally-off and controlling threshold voltage operation obtained on p-channel two-dimensional hole gas (2DHG) hydrogen-terminated (C-H) diamond FET using nitrogen doping in the diamond substrate. In general, a p-channel diamond MOSFET demonstrates the normally-on operation, but the normally-off operation is also a critical requirement of the feasible electronic power devices in terms of safety operation. The characteristics of the C-H diamond MOSFET have been analyzed with the two demonstrated charge sheet models using the two-dimensional Silvaco Atlas TCAD. It shows that the fixed-Fermi level in the bulk diamond is 1.7 eV (donor level) from the conduction band minimum.  However, the upward band bending has been obtained at Al 2 O 3 /SiO 2 /C-H diamond interface indicating the presence of inversion layer without gate voltage. The fixed negative charge model exhibits a strong inversion layer for normally-on FET operation, while the fixed positive charge model shows a weak inversion for normally-off operation.  The maximum current density of a fixed positive interface charge model of the Al 2 O 3 /C-H diamond device is - 290 mA/mm, which corresponds to that of expermental result of Al 2 O 3 /SiO 2 /C-H diamond - 305 mA/mm at a gate-source voltage of - 40 V. Also, the threshold voltage V th  is relatively high at V th  = - 3.5 V, i.e., the positive charge model can reproduce the normally-off operation. Moreover, we also demonstrate that the V th  and transconductance g m  correspond to those of the experimental work., (© 2022. The Author(s).)

A reactive oxygen species (ROS) assay has been widely used for photosafety assessment; however, the phototoxic potential of complex materials, including plant extracts, essential oils, and functional polymers, is unevaluable because of their undefined molecular weights. The present study was undertaken to modify the ROS assay protocol for evaluating phototoxic potentials of those materials with use of their apparent molecular weight (aMw). On preparing sample solutions for the ROS assay, aMw ranging from 150 to 350 was tentatively employed for test substances. The modified ROS assays were applied to 45 phototoxic and 19 non-phototoxic substances, including 44 chemicals and 20 complex materials (plant extracts) for clarification of the predictive performance. Generation of ROS from photo-irradiated samples tended to increase as aMW grew, resulting in the largest number of false-positive predictions at aMW of 350. Some false-negative predictions were also observed when aMW was set at 200 or less. At aMw of 250, all tested phototoxic substances could be correctly identified as photoreactive with no false-negative predictions. Based on these observations, aMw of 250 was found to be suitable for the ROS assay on complex materials, and the sensitivity, specificity, and positive and negative predictivity for the proposed ROS assay were calculated to be 100, 52.6, 83.3, and 100%, respectively. Thus, the proposed approach may be efficacious for predicting phototoxic potentials of complex materials and contribute to the development of new products with a wide photosafety margin.

Some chemicals have been reported to cause metabolite-related phototoxicity, and this study aimed to verify the applicability of photosafety assessment based on photochemical and pharmacokinetic properties to evaluate the metabolite-related phototoxicity risk. The phototoxic risk of imipramine (IMI) and its metabolite, desipramine (DMI), was evaluated by photochemical and pharmacokinetic analyses. IMI and DMI were found to have similar photoreactivities based on the generation of reactive oxygen species. The skin concentrations of IMI and DMI reached maximal levels at approximately 1 and 4 h, respectively, after oral administration of IMI (10 mg/kg), and DMI showed high skin deposition compared with IMI. According to the results, DMI was identified as a contributor to phototoxicity induced by orally-taken IMI. In in vivo phototoxicity testing, ultraviolet A irradiation from 3 to 6 h after oral administration of IMI (100 mg/kg) caused more potent phototoxic reactions compared with that from 0 to 3 h, and DMI yielded by metabolism of IMI would be associated with phototoxic reactions caused by orally-administered IMI. In addition to the data on IMI, a parent chemical, photochemical and pharmacokinetic profiling of its metabolite, DMI, led to reliable phototoxicity prediction of orally-administered IMI. Thus, characterization of the photosafety of metabolites would generate reliable information on the phototoxicity risk of parent chemicals, and the proposed strategy may facilitate comprehensive photosafety assessment of drug candidates in pharmaceutical development., Competing Interests: Declaration of Competing Interest None of the authors have any conflicts of interest associated with this study., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The main objective of this study was to verify the applicable domain of a proposed photosafety screening system, consisting of a reactive oxygen species (ROS) assay and in vitro skin permeation test, for dermally-applied chemicals. Quinolones (QNLs) were selected as test compounds, including enoxacin, flumequine, moxifloxacin, nalidixic acid, orbifloxacin, and oxolinic acid. The ROS assay and in vitro skin permeation test were employed to evaluate photoreactivity and skin deposition of QNLs, respectively. All QNLs exhibited significant ROS generation on exposure to simulated sunlight; in particular, enoxacin was indicative of potent photoreactivity compared with the other 5 QNLs. Steady-state concentration values of flumequine and nalidixic acid were calculated to be 5.0 and 8.2 μg/mL, respectively, and higher than those of the other QNLs. Based on the photoreactivity and skin exposure of QNLs, the phototoxic risk was ranked, and the predicted phototoxic risk by the proposed system was mostly in agreement with observed in vivo phototoxicity, suggesting the applicability of the proposed strategy to photosafety assessment of QNLs. The proposed screening would be efficacious to predict phototoxic risk of dermally-applied chemicals., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background: The aim of this study was to evaluate the quality and diagnostic performance of virtual monochromatic images (VMI) obtained with dual-layer dual-energy computed tomography (DL-DECT) during indirect CT venography (CTV) for deep vein thrombosis (DVT)., Methods and results: This retrospective study was approved by the Institutional Review Board, which waived the requirement for informed consent. We retrospectively enrolled 45 patients who underwent CTV with DL-DECT, and VMI were retrospectively generated. We compared the venous attenuation, noise, contrast, and contrast-to-noise ratio (CNR) between VMI with the highest CNR and conventional CT on paired t-test. Furthermore, we compared the pooled area under the curve (AUC) of each technique with Delong's test in 34 patients who underwent color Doppler ultrasonography. The 40-keV VMI had the best CNR. The noise was significantly lower on 40-keV (9.7±2.5 HU) than on 120-kVp VMI (10.5±2.5 HU; P<0.01). The contrast (120 kVp, 38.2±15.3 HU vs. 40 keV, 131.6±43.6 HU) and CNR (120 kVp, 3.8±1.7 vs. 40 keV, 14.4±6.1) were significantly higher in 40-keV VMI than in 120-kVp VMI (P<0.01). Furthermore, the pooled AUC was significantly higher for 40-keV (0.84) than for 120-kVp VMI (0.78; P=0.03)., Conclusions: In indirect CTV, 40-keV VMI obtained with DL-DECT offers better image quality and diagnostic performance for DVT than conventional CT.

Purpose: The hybrid compressed sensing (hybrid-CS) technique can shorten the acquisition time compared with the sensitivity encoding (SENSE) technique in lumbar MRI. To evaluate the feasibility of a hybrid-CS technique in comparison with 3D isotropic T 2 -weighted turbo spin-echo (3D volume isotropic turbo spin-echo acquisition [VISTA]) MRI of the lumbar spine., Materials and Methods: The Institutional Review Board approved this study and informed consent was obtained from participants prior to study entry. Sixteen healthy volunteers underwent lumbar spine 3D VISTA with conventional parallel imaging for SENSE and hybrid-CS at 3T. We recorded the image acquisition times of SENSE and hybrid-CS. We compared the signal-to-noise ratio (SNR) in spine, cerebrospinal fluid (CSF), lumbar disc, epidural fat, and erector spinae muscle, and the contrast of spine, CSF, and disc, and performed qualitative image analysis assessment, between the two image sequences., Results: The image acquisition time for hybrid-CS was 39.2% shorter than that of SENSE (218.4/358.8 s). The contrast of CSF and SNR of the spine was significantly higher with hybrid-CS than with SENSE (P < 0.05). The SNR of the disc and muscle was significantly higher with SENSE than with hybrid-CS (P < 0.05). There were no significant differences in the contrast of spine, disc, and fat, and SNR of CSF and fat between hybrid-CS and SENSE. There were no significant differences in the qualitative evaluation between hybrid-CS and SENSE., Conclusion: Compared with SENSE, hybrid-CS for 3D VISTA can shorten image acquisition time without sacrificing image quality.

This study involved an attempt to establish a new photosafety screening system for dermally-applied chemicals consisting of a reactive oxygen species (ROS) assay and an in vitro skin permeation test. The ROS assay was undertaken to evaluate photoreactivity of six test compounds, acridine (ACD), furosemide (FSM), hexachlorophene (HCP), 8-methoxypsoralen (MOP), norfloxacin (NFX), and promethazine (PMZ), and the in vitro skin permeation test was conducted to obtain steady-state concentration (C ss ) values of test compounds in removed rat skin. All test compounds were photoreactive based on ROS generation under simulated sunlight exposure. In particular, ROS generation from ACD was high compared with other test compounds, and photoreactivity of ACD was deduced to be potent. The C ss values of ACD, HCP, MOP, and PMZ were over 50 μg/mL, and skin exposure to FSM and NFX was found to be extremely low. Upon these findings, ACD was judged to be highly phototoxic. The rank for phototoxic risk of test compounds based on photoreactivity and in vitro skin exposure was mostly in agreement with outcomes on their in vivo phototoxicity in rats. The proposed strategy, an alternative to animal testing, would be efficacious for photosafety evaluation of drug candidates in early stages of pharmaceutical development., (Copyright © 2019 Elsevier B.V. All rights reserved.)

This study aimed to improve pharmacokinetic behavior and reduce safety concern of cyclosporine A (CsA) by UniORV® approach, a new platform for solid dispersion formulation. CsA-loaded UniORV® (UO/CsA) was prepared, and its physicochemical properties were evaluated in terms of droplet size distribution and dissolution. The pharmacokinetic behavior and nephrotoxic potential of orally-dosed CsA samples (10 mg-CsA/kg) were assessed in rats. After re-dispersion of UO/CsA in water, fine droplets were observed, and the mean diameter of droplets was calculated to be 45 nm. The UniORV® approach markedly improved the dissolution behavior compared with amorphous CsA in water. After oral administration of amorphous CsA, Neoral®, and UO/CsA in rats, UO/CsA exhibited a 32% lower maximum concentration and 5.1 h longer mean residence time than those of Neoral®. The oral absorption of CsA formulations was higher compared with amorphous CsA; in particular, the oral bioavailability of UO/CsA was 71-fold higher than that of amorphous CsA. Neoral® elicited nephrotoxicity with plasma creatinine level of 1.29 mg/dL; however, Neoral®-induced nephrotoxicity was attenuated in UO/CsA, as evidenced by a 15% lower plasma creatinine level of UO/CsA than that of Neoral®. From these findings, UO/CsA might be a promising dosage form with improved biopharmaceutical properties of CsA., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Rationale and Objective: Uterine leiomyomas with high signal intensity on T2-weighted imaging (T2WI) can be difficult to distinguish from sarcomas. This study assessed the feasibility of using machine learning to differentiate uterine sarcomas from leiomyomas with high signal intensity on T2WI on multiparametric magnetic resonance imaging., Materials and Methods: This retrospective study included 80 patients (50 with benign leiomyoma and 30 with uterine sarcoma) who underwent pelvic 3 T magnetic resonance imaging examination for the evaluation of uterine myometrial smooth muscle masses with high signal intensity on T2WI. We used six machine learning techniques to develop prediction models based on 12 texture parameters on T1WI and T2WI, apparent diffusion coefficient maps, and contrast-enhanced T1WI, as well as tumor size and age. We calculated the areas under the curve (AUCs) using receiver-operating characteristic analysis for each model by 10-fold cross-validation and compared these to those for two board-certified radiologists., Results: The eXtreme Gradient Boosting model gave the highest AUC (0.93), followed by the random forest, support vector machine, multilayer perceptron, k-nearest neighbors, and logistic regression models. Age was the most important factor for differentiation (leiomyoma 44.9 ± 11.1 years; sarcoma 58.9 ± 14.7 years; p < 0.001). The AUC for the eXtreme Gradient Boosting was significantly higher than those for both radiologists (0.93 vs 0.80 and 0.68, p = 0.03 and p < 0.001, respectively)., Conclusion: Machine learning outperformed experienced radiologists in the differentiation of uterine sarcomas from leiomyomas with high signal intensity on T2WI., (Copyright © 2019. Published by Elsevier Inc.)