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Abstract Background Ipilimumab (Ipi) plus nivolumab (Nivo) is the recommended first-line treatment for renal cell carcinoma (RCC). This report describes a case where pancreatic metastases disappeared after only two courses of Ipi + Nivo therapy. The primary tumor was cured by surgery, and a pathological Complete Response (pCR) was observed despite multiple serious immune-related Adverse Events (irAEs). Case presentation A 54-year-old woman with RCC and pancreatic metastasis at stage IV, diagnosed with intermediate risk according to the International Metastatic RCC Database Consortium classification, underwent initiation of Ipi + Nivo therapy. On day 26, she developed hyperthyroidism accompanied by tachycardia, leading to the commencement of metoprolol tartrate treatment. Following the resolution of tachycardia, a second course of Ipi + Nivo therapy was administered on day 50. By day 70, the patient exhibited Grade 3 hepatic dysfunction, followed by the onset of hypothyroidism on day 75, necessitating treatment with steroids and levothyroxine. After positive treatment, a Grade 3 skin disorder emerged on day 87 while tapering steroids, prompting treatment with methylprednisolone (mPSL) pulse therapy. The skin disorder responded to steroids, allowing for tapering. However, on day 113, a recurrence of Grade 3 skin disorder occurred, necessitating another mPSL pulse. The patient responded well to treatment, exhibiting improvement in her condition. On day 131, she presented at the hospital with complaints of respiratory distress, prompting a Computed Tomography (CT) scan that revealed interstitial pneumonia. By day 272, subsequent CT imaging showed the disappearance of pancreatic metastasis and shrinkage of the primary tumor. On day 294, she underwent a laparoscopic left nephrectomy. Pathological analysis confirmed a pCR in the primary tumor, indicating successful eradication of RCC through surgical intervention. Conclusions This case report presents a scenario where multiple severe irAEs appeared in a patient, yet metastases disappeared after only two courses of Ipi + Nivo therapy. The patient was ultimately cured by surgery and achieved a pCR. This case highlights that despite the occurrence of severe irAEs during RCC treatment with Ipi + Nivo therapy, they can be managed appropriately to maximize the therapeutic effects of checkpoint inhibitors.

This study evaluates the impact of step size selection on Jacobian-based inverse kinematics (IK) for robotic manipulators. Although traditional constant step size approaches offer simplicity, they often exhibit limitations in convergence speed and performance. To address these challenges, we propose and evaluate novel variable step size strategies. Our work explores three approaches: gradient-based dynamic selection, cyclic alternation, and random sampling techniques. We conducted extensive experiments on various manipulator kinematic chains and IK algorithms to demonstrate the benefits of these approaches. In particular, variable step sizes randomly derived from a normal distribution consistently improve solve rates across all evaluated cases compared to constant step sizes. Incorporating random restarts further enhances performance, effectively mitigating the effect of local minima. Our results suggest that variable step size strategies can improve the performance of Jacobian-based IK methods for robotic manipulators and have potential applications in other nonlinear optimization problems.

Abstract Many haptic guidance systems have been studied over the years; however, most of them have been limited to predefined guidance methods. Calculating guidance according to the operator’s motion is important for efficient human motor adaptation and learning. In this study, we developed a system that haptically provides guidance trajectory by sequential weighting between the operator’s trajectory and the ideal trajectory calculated from a predictive-vision system. We investigated whether motion completion with a predictive-vision system affects human motor accuracy and adaptation in time-constrained goal-directed reaching and ball-hitting tasks through subject experiments. The experiment was conducted with 12 healthy participants, and all participants performed ball-hitting tasks. Half of the participants get forceful guidance from the proposed system in the middle of the experiment. We found that the use of the proposed system improved the operator’s motor performance. Furthermore, we observed a trend in which the improvement in motor performance using this system correlated with that after the washout of this system. These results suggest that the predictive-vision system effectively enhances motor accuracy to the target error in dynamic and time-constrained reaching and hitting tasks and may contribute to facilitating motor learning.

Microinjection technology has been widely applied in various fields, including biology, medicine, and intracytoplasmic sperm injection (ICSI). In a typical ICSI environment, all tasks, such as determining the degree of extension, adjusting the depth of focus, finding polar bodies, and manipulating cells, rely only on visual information; therefore, the person performing ICSI should have particular skills. Consequently, ICSI is generally performed by embryologists specialized in embryo handling. However, with the recent growth in global demand for ICSI, there is a shortage of embryologists and lack of experience among embryologists, and a simple injection system that does not rely on skilled embryologists is required. In this study, we propose a micromanipulation interface that provides a surface tactile sensation with a fabric actuator based on the real-time image measurement of the degree of cell deformation to simplify our understanding of the cell state. The effectiveness of the proposed interface is verified through cell-puncture experiments conducted by novices and one expert.

Force-feedback devices enhance task performance in most robot teleoperations. However, their increased size with additional degrees of freedom can limit the robot’s applicability. To address this, an interface that visually presents force feedback is proposed, eliminating the need for bulky physical devices. Our telepresence system renders robotic hands transparent in the camera image while displaying virtual hands. The forces applied to the robot deform these virtual hands. The deformation creates an illusion that the operator’s hands are deforming, thus providing pseudo-haptic feedback. We conducted a weight comparison experiment in a virtual reality environment to evaluate force sensitivity. In addition, we conducted an object touch experiment to assess the speed of contact detection in a robot teleoperation setting. The results demonstrate that our method significantly surpasses conventional pseudo-haptic feedback in conveying force differences. Operators detected object touch 24.7% faster using virtual hand deformation compared to conditions without feedback. This matches the response times of physical force-feedback devices. This interface not only increases the operator’s force sensitivity but also matches the performance of conventional force-feedback devices without physically constraining the operator. Therefore, the interface enhances both task performance and the experience of teleoperation.

Template matching is a common approach in bin-picking tasks. However, it often struggles in complex environments, such as those with different object poses, various background appearances, and varying lighting conditions, due to the limited feature representation of a single template. Additionally, during the bin-picking process, the template needs to be frequently updated to maintain detection performance, and finding an adaptive template from a vast dataset poses another challenge. To address these challenges, we propose a novel template searching method in a latent space trained by a Variational Auto-Encoder (VAE), which generates an adaptive template dynamically based on the current environment. The proposed method was evaluated experimentally under various conditions, and in all scenarios, it successfully completed the tasks, demonstrating its effectiveness and robustness for bin-picking applications. Furthermore, we integrated our proposed method with YOLO, and the experimental results indicate that our method effectively improves YOLO’s detection performance.

Design considerations concerning the maximum purity of a membrane separator, and the resultant maximum effective selectivity of the membranes were explored by modeling a binary gas membrane separator (pressure-driven permeance) using a dimensionless form. Although the maximum purity has an analytical solution at the limit of zero recovery or stage cut, this solution over-predicts the obtained purity as the recovery is increased. Furthermore, at combinations of high recovery, low feed mole fraction, and low pressure ratio, the maximum purity becomes independent of selectivity above some critical selectivity. As a consequence of this purity limitation, a maximum selectivity is defined at which further increases in selectivity will result in less than a 1% change in the final purity. An equation is obtained that specifies the region in which a limiting purity is less than unity (indicating the existence of a limiting selectivity); operating at less than the limiting pressure ratio results in a purity limitation less than unity. This regime becomes larger and more significant as the inlet mole fraction decreases (e.g., inlet feed mole fraction of 10% and pressure ratio of 100 results in a maximum useful membrane selectivity of only 130 at 95% recovery). These results suggest that membrane research should focus on increasing permeance rather than selectivity for low-concentration separations. The results found herein can be used to set benchmarks for membrane development in various gas separation applications.

Abstract Robotic teleoperation is highly valued for its ability to remotely execute tasks that demand sophisticated human decision-making or that are intended to be carried out by human operators from a distance. However, when using the internet as a communication framework for teleoperation, high latency, and fluctuations make accurate positioning and time-dependent tasks difficult. To mitigate the negative effects of time delay, this paper proposes a teleoperation system that uses cross reality (XR) as a predictive display of the outcome of operators’ intended actions and develops a time-delay aware shared control to fulfill the intention. The system targets a liquid pouring task, wherein a white ring that indicates the intended height of the liquid surface is overlayed onto the beaker in a delayed camera image to close the visual feedback loop on the leader side. Simultaneously, the shared control automatically completes the pouring action to track the intended liquid height. The performance of the proposed system is validated based on liquid pouring experiments performed by human subjects. When compared with direct control, the absolute error rate decreased significantly for a constant round-trip time delay of 0.8 s and 1.2 s, similarly for a time-varying delay of 0.4 s and 0.8 s. Moreover, when the time-varying delay was 0.8 s, operators achieved significantly higher accuracy while maintaining comparable operation time. These results indicate that our proposed system improves operability even in the presence of time-varying delays in communication networks.

Abstract Wearable body weight support systems can assist individuals with mobility impairments in performing daily living activities with greater ease and independence. However, existing systems have limitations in terms of balancing their strength, compact size, interaction with the ground, and driving. In this paper, we present the High-Strength and Flexible Mechanism (HSFM) designed for body weight support. The HSFM utilizes a coiling truss mechanism to perform flexible transformation between a straight and spiral shape. Its complex linkages create the mechanical constraints of the structure and enhance its stiffness. Additionally, the HSFM achieved a high extension rate, effective wire-driven mechanism, and smooth shift of the grounding point. We provide a detailed description of the HSFM, including the simplest 4-linkage mechanism, its mechanical constraints, and the wire-driven mechanism. Moreover, we conducted parametric analysis and geometric calculation on the link structure. The results justified the mechanical constraints of the HSFM and ensured the high extension rate. Further, its functionality for body weight support was evaluated with the hardware and showed sufficient results in terms of strength, smooth grounding, and wire-driven. This novel mechanism has the potential to develop a wearable body weight support robot enhancing daily living activities such as sit-to-stand transfer and walking.

Abstract This sentinel node (SN) biopsy trial aimed to assess its effectiveness in identifying predictive factors of micrometastases and to determine whether elective neck dissection is necessary in oral squamous cell carcinoma. This retrospective study included 55 patients from three previous trials, with positive SNs. The relationship between the sizes of the metastatic focus and metastasis in non-sentinel node (NSN) was investigated. Four of the 55 largest metastatic focus were isolated tumor cells, and the remaining 51 were ranged from 0.2 to 15 mm, with a median of 2.6 mm. The difference of prevalence between 46 negative- and 9 positive-NSN was statistically significant with regard to age, long diameter of primary site and number of cases with regional recurrence. In comparing the size of largest metastatic focus dividing the number of positive SN, with metastaic focus range of

Abstract. Objectives. This study aimed to clarify the significance of therapeutic timing on the effectiveness of nivolumab for treating metastatic renal cell carcinoma. Marterials and methods. Fifty-eight patients with metastatic renal cell carcinoma treated with nivolumab monotherapy were retrospectively studied. Patients who were treated with nivolumab as second-line therapy were included in the second-line group, while the others were included in the later-line group. The clinicopathological characteristics, effects of nivolumab, and prognoses of these groups were compared. Results. Twenty and thirty-eight patients were included in the second-line and later-line groups, respectively. There were no significant differences in the distribution of International Metastatic Renal Cell Carcinoma Database Consotium risk and other clinicopathological characteristics between the 2 groups. The proportion of patients whose objective best response was progressive disease in the second-line group was significantly lower than that in the later-line group (15% vs. 50%, p = 0.0090). The 50% progression-free survival with nivolumab in the second-line group was significantly better than that in the later-line group (not reached and 5 months, p = 0.0018). Multivariate analysis showed that the second-line setting was an independent predictive factor for better progression-free survival (p = 0.0028, hazard ratio = 0.108). The 50% overall survival after starting nivolumab in the second-line and later-line groups was not reached and 27.8 months, respectively (p = 0.2652). Conclusions. The therapeutic efficacy of nivolumab as second-line therapy is expected to be better than that of later therapy.

Soft sensing technologies provide a novel alternative for state estimation in wearables and robotic systems. They allow one to capture intrinsic state parameters in a highly conformable manner. However, due to the nonlinearities in the materials that make up a soft sensor, it is difficult to develop accurate models of these systems. Consequently, design of these soft sensors is largely user defined or based on trial and error. Since these sensors conform and take the shape of the sensing body, these issues are further exacerbated when they are installed. Herein, a framework for the automated design optimization of soft sensors using closed‐loop 3D printing of a recyclable hydrogel‐based sensing material is presented. The framework allows direct printing of the sensor on the sensing body using visual feedback, evaluates the sensor performance, and iteratively improves the sensor design. Following preliminary investigations into the material and morphology parameters, this is demonstrated through the optimization of a sensorized glove which can be matched to specific tasks and individual hand shapes. The glove's sensors are tuned to respond only to particular hand poses, including distinguishing between two similar tennis racket grip techniques.

Grasp intention recognition plays a crucial role in controlling assistive robots to aid older people and individuals with limited mobility in restoring arm and hand function. Among the various modalities used for intention recognition, the eye-gaze movement has emerged as a promising approach due to its simplicity, intuitiveness, and effectiveness. Existing gaze-based approaches insufficiently integrate gaze data with environmental context and underuse temporal information, leading to inadequate intention recognition performance. The objective of this study is to eliminate the proposed deficiency and establish a gaze-based framework for object detection and its associated intention recognition. A novel gaze-based grasp intention recognition and sequential decision fusion framework (GIRSDF) is proposed. The GIRSDF comprises three main components: gaze attention map generation, the Gaze-YOLO grasp intention recognition model, and sequential decision fusion models (HMM, LSTM, and GRU). To evaluate the performance of GIRSDF, a dataset named Invisible containing data from healthy individuals and hemiplegic patients is established. GIRSDF is validated by trial-based and subject-based experiments on Invisible and outperforms the previous gaze-based grasp intention recognition methods. In terms of running efficiency, the proposed framework can run at a frequency of about 22 Hz, which ensures real-time grasp intention recognition. This study is expected to inspire additional gaze-related grasp intention recognition works.

The growing need for high levels of autonomy in Autonomous Robotic Surgery Systems (ARSS) calls for innovative approaches to reduce surgeons’ cognitive load, optimize hospital workflows, and ensure efficient task-level reasoning and adaptation during execution. This paper presents a novel hybrid framework that synergistically combines Task-Motion Planning and Dynamic Behavior Trees for ARSS in Minimally Invasive Surgery. Our approach is designed to address the challenges of coordinating multiple surgical tools within a small workspace, thereby making complex surgical tasks like multi-throw suturing feasible and efficient. Through an extensive evaluation in simulation across diverse initial conditions and noise scenarios, the proposed method demonstrates improved success rates, reduced execution times, and fewer regrasps compared to standalone approaches. Furthermore, it showcases robustness under increased noise conditions. By applying our framework to a complex multi-throw suturing task, we illustrate its capability to seamlessly handle comprehensive suturing tasks, including needle picking, insertion, extraction, and the handover of the needle between Patient Side Manipulators. The results suggest that our hybrid approach not only enhances ARSS autonomy but also adapts effectively to unexpected environmental changes, laying the groundwork for its potential applicability in real-world surgical robotics.

Remote teleoperation has shown significant advancements since the first teleoperation system was proposed by Goertz in the 1940s. In recent years, the research on shared control methodologies in which the robot assists the operators in accomplishing the desired tasks has gained extensive attention. One such important task in teleoperation is object grasping. In this paper, we propose a shared control framework to enhance the teleoperated grasping performance. The proposed framework is built upon a virtual reality device-based direct teleoperation system. In this framework, a template matching-based object point cloud compensation is introduced for multi-angle grasping pose generation. Then, the feasible grasping candidates are selected considering joint constraints-aware manipulability. Finally, the grasping assistance is achieved by trajectory blending with dynamic authority adjustment. To validate the performance of the proposed framework, we carried out experimental evaluations. The output results indicate improved grasping performance in terms of reduced task completion time, linear trajectory, and workload.

Current remote-control interfaces are difficult to operate intuitively while viewing the entire remote display and require familiarity with the operation. The space within an individual’s reach, called the peri-personal space (PPS), assists them in planning their physical movements. Hence, manipulating objects outside one’s PPS is more difficult than doing so inside it. Therefore, this study aimed to develop an interface that creates the illusion of an operator’s finger being transferred to a remote display and transfers the PPS to the virtual finger in the display. To transfer the PPS to a manipulated object, it is necessary to enhance the user’s sense of agency and ownership toward the manipulated target by ensuring it is similar in shape and motion to the user’s body. Long-term input testing confirmed that by transferring the PPS to a virtual finger, there is no significant difference, as suggested by a t-test between the coefficients of the learning curves outside and inside the PPS. Furthermore, when users learned to manipulate the virtual finger outside the PPS under conditions that impaired their sense of agency, even after two weeks of learning, the PPS was not continuously transferred to the virtual finger for more than seven minutes from the start of the virtual finger operation. The experimental results demonstrated that the interface enabled the display located outside the PPS to be operated with the same degree of operability as inside the PPS from the start of the operation, even with a short learning period.

Microinjection technology is widely used in biotechnological processes such as gene manipulation and microinsemination. Generally, microinjection is performed under an optical microscope while viewing the video of the targets in real-time. In the microinjection process, multiple oocytes must be placed in the same droplet, for which the injection must be performed multiple times. Furthermore, the target must be observed at different magnifications during injection and the oocyte transfer operation. Hence, the operators are required to change the magnification and light intensity repeatedly. These tasks are complicated and are a burden for the operators. Thus, the accuracy, reproducibility, and productivity of microinjection depend on the operator’s skill level. In this study, to reduce the burden on the operator and simplify the operation of microinjection, we propose a micromanipulation system that enables both wide-range and high-resolution video presentation with free viewpoint selection. The proposed micromanipulation system is based on a view-expansion microscope system with simultaneous multi-view imaging using a galvanometer mirror and a high-speed vision system. We verify the effectiveness of the proposed system by evaluating the resolution of images presented to the operator and through the experiments involving moving microbeads performed by inexperienced subjects. The experimental results indicate that our micromanipulation system streamlines the task of micromanipulation by eliminating the need to change the objective lens.

Robot-assisted minimally invasive surgery (RMIS) has been shown to be effective in improving surgeon capabilities, providing magnified 3D vision, highly dexterous surgical tools, and intuitive human-robot interfaces for high-precision tool motion control. Robotic surgical tools (RST) are a critical component that defines the performance of an RMIS system. Current RSTs still represent a high cost, with few commercially available options, which limits general access and research on RMIS. We aim to take advantage of recent progress in biocompatible 3D printing and contribute to the development of RMIS technologies, presenting an open platform for low-cost, biocompatible, and customizable RSTs. The proposed design concept consists of a 3-DOF end-effector with a decoupled wrist mechanism, a tool interface module, and a tool drive unit. We validated our end-effector design using Finite Element Analysis (FEA) to confirm that stress generated by high grip forces is maintained below the material yield stress. Validation experiments showed that the proposed RST could provide up to 10N grip forces and up to 3N pulling forces. The proposed control framework exhibited a mean absolute positioning tracking error of approximately 0.1 rad. Finally, we also demonstrated the use of the proposed RST in two surgical training tasks: pick-and-place and stitching. The designs and software control framework are open-access and freely available for customization and fast development at https://github.com/jcolan/OpenRST.

Laparoscopic surgery (LS) is a minimally invasive technique that offers many advantages over traditional open surgery: it reduces trauma, scarring, and shortens recovery time. However, an important limitation is the loss of tactile sensations. Although some progress has been made in robotic-assisted minimally invasive surgery (RMIS) setups, RMIS is still not widely accessible. This review aims to identify which tactile display technologies have been proposed and experimentally validated for the restoration of tactile sensations during conventional laparoscopic surgical tasks. We conducted a systematic review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We identified relevant articles published over the past 10 years through a search on Web of science, Scopus, IEEE Xplore Digital, and PubMed repositories. A total of 143 articles met the inclusion criteria and 24 were included in the final review. From the reviewed articles, we classified the proposed tactile displays into two categories based on the use of skin contact: (i) skin tactile displays, which include vibrotactile, skin-indentation, and grip-feedback devices, and (ii) non-contact tactile displays based on visualization tools. This survey aims to contribute to further research in the area of tactile displays for laparoscopic surgery by providing a better understanding of the current state of the art and identifying the remaining challenges.

In recent years, the demand for effective intracytoplasmic sperm injection (ICSI) for the treatment of male infertility has increased. The ICSI operation is complicated as it involves delicate organs and requires a high level of skill. Several cell manipulation systems that do not require such skills have been proposed; notably, several automated methods are available for cell rotation. However, these methods are unfeasible for the delicate ICSI medical procedure because of safety issues. Thus, this study proposes a microscopic system that enables intuitive micropipette manipulation using a haptic device that safely and efficiently performs the entire ICSI procedure. The proposed system switches between field-of-view expansion and three-dimensional image presentation to present images according to the operational stage. In addition, the system enables intuitive pipette manipulation using a haptic device. Experiments were conducted on microbeads instead of oocytes. The results confirmed that the time required for the experimental task was improved by 52.6%, and the injection error was improved by 75.3% compared to those observed in the conventional system.

In the context of Minimally Invasive Surgery, surgeons mainly rely on visual feedback during medical operations. In common procedures such as tissue resection, the automation of endoscopic control is crucial yet challenging, particularly due to the interactive dynamics of multi-agent operations and the necessity for real-time adaptation. This paper introduces a novel framework that unites a Hierarchical Quadratic Programming controller with an advanced interactive perception module. This integration addresses the need for adaptive visual field control and robust tool tracking in the operating scene, ensuring that surgeons and assistants have optimal viewpoint throughout the surgical task. The proposed framework handles multiple objectives within predefined thresholds, ensuring efficient tracking even amidst changes in operating backgrounds, varying lighting conditions, and partial occlusions. Empirical validations in scenarios involving single, double, and quadruple tool tracking during tissue resection tasks have underscored the system’s robustness and adaptability. The positive feedback from user studies, coupled with the low cognitive and physical strain reported by surgeons and assistants, highlight the system’s potential for real-world application.

Abstract The use of intracytoplasmic sperm injection (ICSI), an assisted reproductive technique (ART), is increasing widely. ICSI is currently performed by specially skilled embryologists. However, with the increasing demand for ART, the shortage of skilled embryologists has become a problem. Therefore, we propose an immersive micromanipulation system that requires no special skills for efficient and accurate micromanipulation. Our proposed system is composed of a real-time three-dimensional (3D) imaging microscope and 3D operation interfaces. The 3D operation interfaces are stationary pen-type or wearable glove-type interfaces. In this system, an operator wearing a head-mounted display (HMD) and using 3D operation interfaces is immersed in a virtual micromanipulation space. The operator can move the pipettes by 3D operation interface and freely change the viewpoint. We verified that the proposed system improves the speed and accuracy of operating a pipette through two types of experiments with subjects.

Abstract Prophylactic elective neck dissection (ND) with navigation surgery using radioisotope-based sentinel lymph node biopsy (SLNB) is non-inferior to elective ND in terms of survival but has an advantage in postoperative functional disability. We conducted a subgroup analysis to identify predictive factors for false-negative (FN)-SLNB in patients with early oral cavity cancer. This study is a supplementary analysis using the dataset of a previously reported randomized clinical trial on SLN navigation surgery for oral cancers. This study investigated the association of clinical and SLN-related factors with false-negative cases in the SLNB group. From 2011 to 2016, 275 patients were enrolled and randomly assigned to the ND and SLNB study groups, with 134 patients assigned to the SLNB group. In the SLNB group, seven cases with negative SLNs and neck recurrences were judged as FN-SLNBs according to the general definition. The number of detected SLNs with and without adjusting for the propensity score was significantly associated with FNs in the logistic analysis. FN-SLNB was associated with the number of identified SLNs, suggesting the need for careful postoperative monitoring for neck recurrence in patients with one or two identified SLNs after acquiring sufficient experience in the identification technique.

Gait analysis and evaluation are vital for disease diagnosis and rehabilitation. Current gait analysis technologies require wearable devices or high-resolution vision systems within a limited usage space. To facilitate gait analysis and quantitative walking-ability evaluation in daily environments without using wearable devices, a mobile gait analysis and evaluation system is proposed based on a cane robot. Two laser range finders (LRFs) are mounted to obtain the leg motion data. An effective high-dimensional Takagi-Sugeno-Kang (HTSK) fuzzy system, which is suitable for high-dimensional data by solving the saturation problem caused by softmax function in defuzzification, is proposed to recognize the walking states using only the motion data acquired from LRFs. The gait spatial-temporal parameters are then extracted based on the gait cycle segmented by different walking states. Besides, a quantitative walking-ability evaluation index is proposed in terms of the conventional Tinetti scale. The plantar pressure sensing system records the walking states to label training data sets. Experiments were conducted with seven healthy subjects and four patients. Compared with five classical classification algorithms, the proposed method achieves the average accuracy rate of 96.57%, which is improved more than 10%, compared with conventional Takagi-Sugeno-Kang (TSK) fuzzy system. Compared with the gait parameters extracted by the motion capture system OptiTrack, the average errors of step length and gait cycle are only 0.02 m and 1.23 s, respectively. The comparison between the evaluation results of the robot system and the scores given by the physician also validates that the proposed method can effectively evaluate the walking ability.

Abstract. Background:. There are various alternative first-line therapeutic options besides tyrosine kinase inhibitors (TKIs) for metastatic renal cell carcinoma (mRCC). To inform therapeutic decision-making for such patients, this study aimed to identify predictive factors for resistance to TKI. Materials and methods:. A total of 239 cases of mRCC patients who received first-line TKI therapy were retrospectively studied. Patients with a radiologic diagnosis of progressive disease within 3 months after initiating therapy were classified as primary refractory cases; the others were classified as non-primary refractory cases. The association between primary refractory cases and age, gender, pathology findings, serum c-reactive protein (CRP) level, metastatic organ status, and 6 parameters defined by the International Metastatic Renal Cell Carcinoma Database Consortium were analyzed. Results:. Of 239 cases, 32 (13.3%) received a radiologic diagnosis of progressive disease within 3 months after initiating therapy. The rates of sarcomatoid differentiation, hypercalcemia, a serum CRP level of 0.3 mg/dL or higher, presence of liver metastasis, anemia, and time from diagnosis to treatment interval of less than a year were significantly higher in the primary refractory group. Multivariate analysis showed that sarcomatoid differentiation, hypercalcemia, a serum CRP level of 0.3 mg/dL or higher, and liver metastasis were independently associated with primary refractory disease. A risk-stratified model based upon the number of patients with these factors indicated rates of primary refractory disease of 4.0%, 10.1%, and 45.0% for patients with 0, 1, and 2 or more factors, respectively. Conclusions:. Sarcomatoid differentiation, hypercalcemia, an elevated serum CRP level, and presence of liver metastasis were associated with primary refractory disease in mRCC patients receiving first-line TKI therapy. These results provide clinicians with useful information when selecting a first-line therapeutic option for mRCC patients.

Abstract Background Obesity has been considered as a risk factor influencing operative difficulty. It was reported that body mass index (BMI; kg/m2) did not always properly reflect the degree of a patient’s visceral fat. The purpose of this study is to retrospectively investigate the association of operative outcomes and obesity indices including visceral fat area (VFA; cm2) and BMI in retroperitoneoscopic nephrectomy (RN). Methods We retrospectively reviewed consecutive 96 RN procedures performed from September 2016 to June 2020. We divided patients into BMI obese group (BMI ≥ 25, n = 25) and BMI normal group (BMI

Minimally invasive surgery has undergone significant advancements in recent years, transforming various surgical procedures by minimizing patient trauma, postoperative pain, and recovery time. However, the use of robotic systems in minimally invasive surgery introduces significant challenges related to the control of the robot’s motion and the accuracy of its movements. In particular, the inverse kinematics (IK) problem is critical for robot-assisted minimally invasive surgery (RMIS), where satisfying the remote center of motion (RCM) constraint is essential to prevent tissue damage at the incision point. Several IK strategies have been proposed for RMIS, including classical inverse Jacobian IK and optimization-based approaches. However, these methods have limitations and perform differently depending on the kinematic configuration. To address these challenges, we propose a novel concurrent IK framework that combines the strengths of both approaches and explicitly incorporates RCM constraints and joint limits into the optimization process. In this paper, we present the design and implementation of concurrent inverse kinematics solvers, as well as experimental validation in both simulation and real-world scenarios. Concurrent IK solvers outperform single-method solvers, achieving a 100% solve rate and reducing the IK solving time by up to 85% for an endoscope positioning task and 37% for a tool pose control task. In particular, the combination of an iterative inverse Jacobian method with a hierarchical quadratic programming method showed the highest average solve rate and lowest computation time in real-world experiments. Our results demonstrate that concurrent IK solving provides a novel and effective solution to the constrained IK problem in RMIS applications.

Abstract Background Various biomarkers are being developed for the early diagnosis of cancer and for predicting its prognosis. The aim of this study is to evaluate the diagnostic significance of serum CD109 in head and neck squamous cell carcinoma (HNSCC). Methods The serum CD109 levels in a total of 112 serum samples collected before and after surgery from 56 HNSCC patients were analyzed with an enzyme‐linked immunosorbent assay (ELISA). The clinical factor that showed a statistically significant association with both the preoperative serum CD109 level, and the CD109 index: which was defined as the ratio of the preoperative serum CD109 level to the postoperative serum CD109 level, were assessed. The correlations between the serum CD109 levels and lymph node density (LND), pathological features such as lymphatic invasion, and serum SCC antigen levels were also assessed. Results The ELISA measurement revealed that preoperative serum CD109 levels were elevated in patients with node metastasis‐positive and stage IV disease, in comparison to those with node metastasis‐negative and Stage I+II+III disease, respectively. A multiple regression analysis indicated that serum CD109 level was significantly associated with the node metastasis status. A Spearman's rank correlation analysis also revealed a positive correlation between the preoperative serum CD109 level and LND. Furthermore, the probabilities of the overall and relapse‐free survival were significantly lower in patients with a preoperative serum CD109 level of ≥38.0 ng/ml and a CD109 index of ≥1.6, respectively, than in others. There was no significant correlation between the serum CD109 and SCC antigen levels. Conclusions The serum CD109 levels were elevated in patients with advanced stage disease, reflecting the node metastasis status. CD109 in sera could be a novel prognostic marker for HNSCC involving lymph node metastasis.

Introduction Small cell carcinoma of urinary bladder is rare and has an aggressive malignant behavior and poor prognosis. Advanced bladder cancers are treated with immune checkpoint inhibitors, however, its efficacy for small cell carcinoma of urinary bladder is unclear. Case presentation A 54‐year‐old female, diagnosed with clinical stage T2N0M0 small cell carcinoma of urinary bladder, underwent radical cystectomy after three cycles of etoposide‐cisplatin neoadjuvant chemotherapy. Despite the fact that pathological examination revealed no residual carcinoma in bladder in her cystectomy specimen, local recurrence of a 60‐mm mass detected in the follow‐up investigation 7.5 months later. This was completely treated by pembrolizumab without any adverse effects. Immunohistochemical staining revealed that the tumor had no programmed death ligand 1 expression but it showed CD8‐positive T‐lymphocyte infiltration into the tumor. Conclusion Immune checkpoint inhibitors might have curative potentials for treatment of small cell carcinoma of urinary bladder.

Abstract The currently available exoskeleton for assisting the paraplegic patient in walking usually adapts a pre-programmed gait that involves the patient following an exoskeleton lead. The system allows the patient to hold a pair of canes in order to keep balance, and does not contribute to keeping balance without the patient’s action. This paper proposes an algorithm based on the zero moment point (ZMP) to modify the gait generated through human walking synergy for paraplegic patients who make use of the exoskeleton system and hold their canes. The proposed ZMP will enable the paraplegic patient to keep balance during walking and also reduce the burden in maintaining balance. First, a pair of cane is used as an interface to control the user’s walking and then, the synergy between legs and canes is used to synchronize the user’s walking intention during the exoskeleton movement. The walking synergy is extracted from the able-bodied subject walking with a pair of canes and analyzed using principal component analysis (PCA). In order to improve the walking stability, the hip joint angle on stance leg during walking was modified based on ZMP. Furthermore, a nonlinear inverted pendulum (NIP) model was utilized in order to generate a gait with a fully stretched knee joint angle that is similar to human gait. The proposed method was verified via the Gazebo simulation using a walking robot to simulate a patient wearing an exoskeleton. The experiment results show that the walking stability was highly improved after gait modification.

Chabazite (CHA)-type zeolite membranes are a potential material for CO2 separations because of their small pore aperture, large pore volume, and low aluminum content. In this study, the permeation and separation properties were evaluated using a molecular simulation technique with a focus on improving the CO2 separation performance. The adsorption isotherms of CO2 and CH4 on CHA-type zeolite with Si/Al = 18.2 were predicted by grand canonical Monte Carlo, and the diffusivities in zeolite micropores were simulated by molecular dynamics. The CO2 separation performance of the CHA-type zeolite membrane was estimated by a Maxwell–Stefan equation, accounting for mass transfer through the support tube. The results indicated that the permeances of CO2 and CH4 were influenced mainly by the porosity of the support, with the CO2 permeance reduced due to preferential adsorption with increasing pressure drop. In contrast, it was important for estimation of the CH4 permeance to predict the amounts of adsorbed CH4. Using molecular simulation and the Maxwell–Stefan equation is shown to be a useful technique for estimating the permeation properties of zeolite membranes, although some problems such as predicting accurate adsorption terms remain.

The transesterification conversion of methyl ether can be enhanced by the removal of the byproduct methanol using methanol permselective faujasite (FAU-type) zeolite membranes. However, the authors previously observed that the methanol flux during the transesterification reaction was lower than the predicted flux. Therefore, this study investigated the stability of FAU-type zeolite membranes in the presence of organic components associated with the transesterification reaction of methyl hexanoate and 1-hexanol. The stability was defined in terms of changes in methanol permeance and zeolite structure. The effect of reaction components (methanol, 1-hexanol, methyl hexanoate, and hexyl hexanoate) on the FAU-type zeolite structure and the methanol permeation performance of the FAU-type zeolite membranes were evaluated to find the component causing the lower methanol flux. From these results, two esters were found to adsorb strongly on the FAU-type zeolite. The methanol flux of the FAU-type zeolite membrane was examined after vapor exposure of each of the four reaction chemicals at 373 K for 8 h. In the case of methyl hexanoate and hexyl hexanoate vapor exposure, the methanol flux was reduced by about 75% compared to the initial flux of 15 kg m−2 h−1. These results indicated methanol permeation performance was inhibited by the adsorption of esters.

There is a growing need for robots that can be remotely controlled to perform tasks of one’s own choice. However, the SoA (Sense of Agency: the sense of recognizing that the motion of an observed object is caused by oneself) is reduced because the subject of the robot motion is identified as external due to shared control. To address this issue, we aimed to suppress the decline in SoA by presenting auditory feedback that aims to blur the distinction between self and others. We performed the tracking task in a virtual environment under four different auditory feedback conditions, with varying levels of automation to manipulate the virtual robot gripper. Experimental results showed that the proposed auditory feedback suppressed the decrease in the SoA at a medium level of automation. It is suggested that our proposed auditory feedback could blur the distinction between self and others, and that the operator attributes the subject of the motion of the manipulated object to himself.

Bioactuators have been developed in many studies in the recent decade for actuators of micro-biorobots. However, bioactuators have not shown the same power as animal muscles. Centrifugal force was used in this study to increase the cell density of cultured muscle cells that make up the bioactuator. The effect of the centrifugal force on cells in the matrix gel before curing was investigated, and the optimal centrifugal force was identified to be around 450× g. The compressed modular bioactuator (C-MBA) fabricated in this study exhibited 1.71 times higher cell density than the conventional method. In addition, the contractile force per unit cross-sectional area was 1.88 times higher. The proposed method will contribute to new bioactuators with the same power as living muscles in animals.

A wirelessly powered four-channel neurostimulator was developed for applying selective Functional Electrical Stimulation (FES) to four peripheral nerves to control the ankle and knee joints of a rat. The power of the neurostimulator was wirelessly supplied from a transmitter device, and the four nerves were connected to the receiver device, which controlled the ankle and knee joints in the rat. The receiver device had functions to detect the frequency of the transmitter signal from the transmitter coil. The stimulation site of the nerves was selected according to the frequency of the transmitter signal. The rat toe position was controlled by changing the angles of the ankle and knee joints. The joint angles were controlled by the stimulation current applied to each nerve independently. The stimulation currents were adjusted by the Proportional Integral Differential (PID) and feed-forward control method through a visual feedback control system, and the walking trajectory of a rat’s hind leg was reconstructed. This study contributes to controlling the multiple joints of a leg and reconstructing functional motions such as walking using the robotic control technology.

Abstract In this paper, toward robotic gait assistance, we investigate the feasibility of a cane-type assistive mobile robot accompanying the user autonomously through a clinical pilot experiment. As widely known, gait ability is important for all people to keep their quality of life. However, for people having weakened lower limbs such as elderly people, their postural sway during walking could be insuppressible and cause falling. To support the gait motion of elderly people, our group has been developing a series of hand-holding cane robots named Intelligent Cane. Such assistive robots are expected to remove barriers to the independent lives of elderly people. Recently, we have focused on the potential of a companion robot that follows the user ahead and can be touched or grasped for bracing whenever the user needs it. In order to demonstrate proof of our concept through an experiment with a motion capture system, we propose a user companion strategy that enables our cane robot to keep a constant relative distance between the robot and the user walking on a treadmill. We evaluate the accuracy of the user companion in an experiment where a user walks on a treadmill. Then, we conduct a clinical experiment with three healthy subjects walking on with the treadmill with our cane robot as a pilot study. Through the clinical experiment, we evaluate a postural stabilization effect of physical interaction with the robot and discuss the feasibility of our robotic gait assistance methodology.

Abstract This paper reports negative effects on runner’s motions which are supported by an exoskeleton attached to his/her lower limbs. A wearable assistive device has generally been developed to support motions of a wearer, while the device may disturb wearer’s motions due to physical features, including expanded his/her body outline and device’s weight. The expanded outline can exert adverse influence that limits range of motion of a wearer. In this paper, we focus on lower limb motions of a runner who puts an exoskeleton on his/her lower limbs to receive physical assistance. We simulated influence of medial parts of the exoskeleton on running through experiments with seven runners wearing one of three couples of rectangular-shaped light blocks (10 mm, 20 mm or 30 mm in thickness) on the medial sides of both thighs. These blocks increased step width but the 30 mm-thick blocks only increased net running heat rates by 6.05 bpm compared with that of running without blocks. This result shows that a wearable device which is equipped with components less than 20 mm-thick on each medial part of a runner’s thigh has little detrimental effects on running motions.

Abstract Recently, wearable extra robotic limbs that aim to enhance the functionality and capability of human operators as extra arms or fingers have become an active research subject among robotics researchers. Improving the operability of the extra robotic limbs is required for the human operators, an approach for which is to induce robotic embodiment. In this paper, we focus on the update of sense of self-location which is the key aspect of embodiment and contributes to the body representation update, and we elucidate dominant factors which induce the embodiment of an extra robotic thumb (ERT). The experiments are conducted to compare the performance of the reaching task of the ERT under three separately given conditions, of which two are somatosensory feedbacks: (1) tactile and position feedback from the fingertips and (2) tactile and position feedback from the human face, and one is a non-somatosensory feedback: (3) auditory feedback. As a result, we confirmed that the somatosensory feedback from finger tips has a large contribution for the update of sense of self-location.

Promising treatments for upper motor neuron disease are emerging in which motor function is restored by brain–computer interfaces and functional electrical stimulation. At present, such technologies and procedures are not applicable to lower motor neuron disease. We propose a novel therapeutic strategy for lower motor neuron disease and injury integrating neural stem cell transplantation with our new functional electrical stimulation control system. In a rat sciatic nerve transection model, we transplanted embryonic spinal neural stem cells into the distal stump of the peripheral nerve to reinnervate denervated muscle, and subsequently demonstrated that highly responsive limb movement similar to that of a healthy limb could be attained with a wirelessly powered two-channel neurostimulator that we developed. This unique technology, which can reinnervate and precisely move previously denervated muscles that were unresponsive to electrical stimulation, contributes to improving the condition of patients suffering from intractable diseases of paralysis and traumatic injury.

This study proposes a visual sensing system to investigate the self-propelled motions of droplets. In the visual sensing of self-propelled droplets, large field-of-view and high-resolution images are both required to investigate the behaviors of multiple droplets as well as chemical reactions in the droplets. Therefore, we developed a view-expansive microscope system using a color camera head to investigate these chemical reactions; in the system, we implemented an image processing algorithm to detect the behaviors of droplets over a large field of view. We conducted motion tracking and color identification experiments on the self-propelled droplets to verify the effectiveness of the proposed system. The experimental results demonstrate that the proposed system is able to detect the location and color of each self-propelled droplet in a large-area image.

Background: Patients with human papillomavirus (HPV)-associated oropharyngeal squamous cell carcinoma (OPSCC) have a significantly better treatment response and overall survival (OS) rates than non-HPV-associated OPSCC. Objectives: We conducted the present study to further characterize the interplay between lifestyle risk factors, which are not only HPV status, but also smoking history and alcohol consumption, and the OS to optimize the treatment of patients with OPSCC. Materials and Methods: Between January 2006 and December 2013, 94 patients newly diagnosed with OPSCC were treated with curative intent at Aichi Cancer Center Hospital (Nagoya, Japan). To determine negative prognostic factors associated with the OS, univariate and multivariable Cox regression analyses were performed. Results: Of the 94 OPSCC patients, 53 (56.4%) were positive for HPV. The univariate analysis revealed that T classification, smoking history, alcohol consumption, and HPV status were significant determinants of the OS. In the multivariate analysis, adjusted for the clinical stage, smoking history, alcohol consumption, HPV status, and a smoking history of >10 pack-years was an independent negative prognostic factor for the OS among patients with OPSCC (HR: 10.4, 95 %CI: 1.34–80.6, p < 0.05). Conclusions: Smoking is a very important negative prognostic factor even in cases of HPV-associated OPSCC. The impact of smoking needs to be reaffirmed when deciding on treatment plans and de-escalation trials in OPSCC, even in cases of HPV-associated OPSCC.

Abstract This paper addresses a reference gait speed generator for limit-cycle-based bipedal gait of humanoid robots in order to achieve secure and efficient acceleration and deceleration without falling down at respective gait speeds. The reference gait speed generator is hard to be developed by analytical approaches due to the necessity of barren work for identifying the respective basins of attraction. We challenge this issue by designing virtual dynamics among a robot, a virtual leader point, and a goal, and adapting it according to a falling risk of the robot. The virtual dynamics, which has settling and acceleration times as design parameters, gives the reference speeds derived from states of the robot and the leader point to a gait speeds controller. In the dynamics, the robot’s mass is optimized virtually to maximize efficiency while ensuring stability stochastically by using a selection algorithm for locomotion. Even when there were obstacles or an up slope in traveling courses of simulations, the robot achieved the autonomous traveling from the start to the goal securely. Specific resistance was also kept small in comparison with local-stability-based walking. The proposed method makes the limit-cycle-based bipedal gait more practical and contributes toward replacing the major method that ensures stability of every step.

Abstract Background Spontaneous esophageal rupture, also known as Boerhaave syndrome, is a very serious life-threatening benign disease of the gastrointestinal tract. It is typically caused by vomiting after heavy eating and drinking. However, in our patient, because of a combination of hypopharyngeal cancer with stenosis and chemoradiotherapy (CRT), which caused chemotherapy-induced vomiting, radiotherapy-induced edema, relaxation failure, and delayed reflexes; resistance to the release of increased pressure due to vomiting was exacerbated, thus leading to Boerhaave syndrome. To the best of our knowledge, this is the first report of a patient with esophageal rupture occurring during CRT for hypopharyngeal cancer with stenosis. Case presentation A 66-year-old man with a sore throat was referred to our hospital. He was found to have stage IVA hypopharyngeal cancer, cT2N2bM0, and underwent radical concurrent CRT consisting of weekly cisplatin (30 mg/m2) and radiation (70 Gy/35fr), for larynx preservation. On day 27 of treatment, he vomited, which was followed by severe left chest pain radiating to the back and the upper abdomen. Enhanced computed tomography (CT) revealed extensive mediastinal emphysema and a small amount of left pleural effusion. Esophagography revealed extravasation into the left thoracic cavity, and the patient was diagnosed with an intrathoracic rupture type of Boerhaave syndrome. He underwent emergency left thoracotomy 21 h after the onset. The ruptured esophageal wall was primarily repaired by closure with two-layer suturing and covered by a pedicled omentum. A jejunostomy tube was placed for postoperative enteral nutrition. On postoperative day (POD) 16, the patient was transferred to head and neck surgery to finish CRT and was discharged on POD 56. He has survived without relapse for 11 months after surgery. Conclusion Patients with head and neck cancer are at risk for developing Boerhaave syndrome during CRT. In addition, since such patients often are in poor overall condition because of immunosuppression and protracted wound healing, Boerhaave syndrome can rapidly lead to severe life-threatening infections such as empyema and mediastinitis. Therefore, awareness of this condition is important so that appropriate treatment can rapidly be implemented to increase the likelihood of a good outcome.

Abstract Background Our study analyzes the effect of magnesium supplementation on nephrotoxicity in patients receiving cisplatin for head and neck cancer. Methods We retrospectively reviewed the medical records of patients with head and neck cancer who received two doses of cisplatin (80 mg/m2) and 5-fluorouracil (800 mg/m2) 3 weeks apart from August 2008 to October 2012. The regimen prior to 2011 (crystalloid-only) involved the administration of 1000 mL of lactated Ringer’s solution on the day prior to cisplatin infusion and 2000 mL of continuous infusion of saline on the day of cisplatin infusion. The regimen after 2011 (magnesium-supplemented) did not involve hydration on the day before cisplatin administration but used 1000 mL of 0.9% saline with magnesium sulfate (20 mEq) administered for 3 hours before cisplatin infusion. Results Sixty-five patients were treated with the crystalloid-only regimen and 56 patients with the magnesium-supplemented regimen. The mean creatinine clearance in the magnesium-supplemented group decreased by 4.9 mL/kg/min, whereas that in the crystalloid-only group decreased by 15.0 mL/kg/min after two courses. In multivariate analysis, only magnesium-supplemented hydration was an independent predictive factor for preventing cisplatin-induced nephrotoxicity (odds ratio = 0.157, 95% confidence interval 0.030–0.670, P = 0.0124). Conclusion We demonstrated that an intravenous hydration regimen supplemented with magnesium prevented cisplatin-induced nephrotoxicity in patients with head and neck cancer.

Abstract In recent years, there has been great interest in the possibility of using artificial limbs as an extension of the human body as well as replacement of lost limbs. In this paper, we develop a sixth finger system as an extension of the human body. We then investigate how an extra robotic thumb, that works as a sixth finger and gives somatosensory feedback to the user, modifies the body schema, and also affecting the self-perception of existing limbs. The sixth robotic finger is controlled with the thumb of the opposite hand, and contact information is conveyed via electrostimulation to the tip of the thumb controlling the movement. We conducted reaching task experiments with and without visual information to evaluate the level of embodiment of the sixth robotic finger and the modification of the self-perception of the finger controlling the system. The experimental results indicate that not only the sixth finger is incorporated into the body schema of the user, but also the body schema of the controlling finger is modified; ability of the brain to adapt to different scenarios and geometries of the body is also implied.

The separation of non-aqueous mixtures is important for chemical production, and zeolite membranes have great potential for energy-efficient separation. In this study, the influence of the framework structure and composition of zeolites on the permeation and separation performance of methanol through zeolite membranes were investigated to develop a methanol permselective zeolite membrane. As a result, the FAU-type zeolite membrane prepared using a solution with a composition of 10 SiO2:1 Al2O3:17 Na2O:1000 H2O showed the highest permeation flux of 86,600 μmol m−2 s−1 and a separation factor of 6020 for a 10 wt% methanol/methyl hexanoate mixture at 353 K. The membrane showed a molecular sieving effect, reducing the single permeation flux of alcohol with molecular size for single-component alcohols. Moreover, the permeation flux of methanol and the separation factor increased with an increase in the carbon number of the alcohols and methyl esters containing 10 wt% methanol. In this study, the permeation behavior of FAU-type zeolite membranes was also discussed based on permeation data. These results suggest that the FAU-type zeolite membrane has the potential to separate organic solvent mixtures, such as solvent recycling and membrane reactors.

In this study, an NaA-type zeolite membrane was prepared, and the dehydration performances of the membrane were determined by the pervaporation for several organic solvents to understand the lower dehydration performances of zeolite membranes for NMP solutions than those for alcohols. For a 90 wt% ethanol solution at 348 K, the permeation flux and separation factor of the membrane were 3.82 kg m−2 h−1 and 73,800, respectively. The high dehydration performances were also obtained for alcohols and low boiling solvents (acetonitrile, acetone, methyl ethyl ketone (MEK) and tetrahydrofuran (THF)). However, the permeation flux and separation factors decreased significantly for high boiling solvents, such as N,N-dimethylacetamide (DMA), N,N-dimethyl formamide (DMF), dimethyl sulfoxide (DMSO) and N-methyl-2-pyrrolidone (NMP). The influences of the water content and temperature on the dehydration performances for the NMP solutions were determined to understand the lower dehydration performances for those solvents. Those results suggest that the lower dehydration performances for the high boiling solvents were attributed to the lower vapor pressures of water and the higher permeances of those solvents. Furthermore, this study proposes that the permeation behaviors through zeolite membranes could be understood by the determination of the effect of temperature on the permeance of individual components.

Ammonia (NH3) and hydrogen sulfide (H2S) are hazardous and odorous gases. A special device that is not affected by other gases is necessary so that it can detect such gases. Zeolite membranes can separate the desired component selectively by molecular sieving and selective adsorption. LTA-, MFI-, and FAU-type zeolite membranes were prepared in this study, and the permeation and separation performances were determined for the ternary mixture of NH3, H2S, and N2 to develop an NH3 selectively permeable membrane. Although the separation factors of NH3 were high enough for the LTA-type zeolite membrane, the NH3 permeance was the lowest among the three membranes. In contrast, the FAU-type zeolite membrane with Si/Al = 1.35 showed a high enough NH3 permeance and a NH3/N2 separation factor. The membrane modification and varying the membrane composition were carried out to reduce the H2S permeance. As a result, the H2S permeance could be decreased by modification with silane coupling agents, and a separation factor of NH3 toward H2S of over 3000 was achieved.

Computational chemistry is a promising technique for the prediction of material properties. Adsorption and diffusion behaviors in zeolite micropores are important for zeolite membranes. In this study, we investigated novel non-bonding interaction parameters of all-silica zeolites for the prediction of the adsorption and diffusion behaviors by focusing on the Si atom of zeolite frameworks. Our parameters (σ = 0.421 nm, ε = 0.954 kJ mol−1, and q = +1.10 e) were close to theoretically derived values, and the adsorption isotherms of CO2 and CH4 on several zeolites could be predicted with high accuracy. Furthermore, the parameters gave the suitable self-diffusivities of CO2 and CH4 within MFI-type zeolite micropores through molecular dynamics simulation. Those suggest that our derived parameters are useful for selecting zeolite structure as the membrane material.

In this article, we propose a new actuator named the modular bio-actuator (MBA). The MBA has two tendon structures made of polydimethylsiloxane (PDMS) at both ends of the bio-actuator. The MBA can be easily handled and fixed on an artificial micro-robot body to increase its design flexibility and output power. The tendon structures were connected to a bio-actuator in the form of a chain structure, and the connection between the tendon structures and the bio-actuator was maintained for more than three weeks. The contraction length of the MBA was linearly increased when the DC voltage applied to the MBA was increased. The MBA contracted over 200 µm when a DC voltage of 10 V and 1 Hz was applied to the bio-actuator. The output power of the MBA was measured using a PDMS cantilever, and the total output power of the MBA increased linearly when multiple MBAs were stacked on a PDMS cantilever. This study was aimed at improving the design flexibility and controllability of micro-robots and bionic systems.