A Long Life Moisture-Enabled Electric Generator Based on Ionic Diode Rectification and Electrode Chemistry Regulation.

Considerable efforts have recently been made to augment the power density of moisture-enabled electric generators. However, due to the unsustainable ion/water molecule concentration gradients, the ion-directed transport gradually diminishes, which largely affects the operating lifetime and energy efficiency of generators. This work introduces an electrode chemistry regulation strategy into the ionic diode-type energy conversion structure, which demonstrates 1240 h power generation in ambient humidity. The electrode chemical regulation can be achieved by adding Cl-. The purpose is to destroy the passivation film on the electrode interface and provide a continuous path for ion-electron coupling conduction. Moreover, this device simultaneously satisfies the requirements of fast trapping of moisture molecules, high rectification ratio transport of ions, and sustained ion-to-electron current conversion. A single device can deliver an open-circuit voltage of about 1 V and a peak short-circuit current density of 350 µA cm-2. Finally, the first-principle calculations are carried out to reveal the mechanism by which the electrode surface chemistry affects the power generation performance.

Efficient and cold-tolerant moisture-enabled power generator combining ionic diode and ionic hydrogel.

The ionic diode structure has become one of the attractive structures in the field of moisture-based power generation. However, existing devices still suffer from poor moisture trapping, low surface charge, and inefficient ion separation, resulting in low output power. Moreover, water freezes at low temperatures (<0 °C), limiting the ionic diode structure to generate electricity in cold environments. In this paper, a moisture-enabled power generator has been designed and fabricated, which assembles a negatively charged ionic hydrogel film and a positively charged anodized aluminum oxide (AAO) film to construct a heterojunction. The hydrogel polymer network is modified with a large number of sulfonate groups that dissociate to provide nanoscale pores with high surface charge to improve the rectification ratio. And the lithium chloride (LiCl) salt with high hydration ability is added to the hydrogel as a moisture-trapping and anti-freezing component. Usually salt ions reduce the Debye length, so that the ion transport is finally not controlled by the electric double layer (EDL) and the rectification fails. Interestingly, due to the natural affinity of the hydrogel polymer network for LiCl, LiCl is locked on the hydrogel side and does not easily enter the AAO pores to change the distribution of EDL within the nanochannel. As a result, the device rectification ratio is almost independent of the amount of LiCl addition, demonstrating an excellent balance of high output power and high freeze resistance. Ultimately, the device exhibits excellent power generation performance in the -20 °C to 60 °C temperature range and 15% to 93% RH humidity range. Typically, under high humidity (93% RH) at room temperature (25 °C), it provides an open-circuit voltage of 1.25 V and a short-circuit current of 300 µA cm-2, with an on-load output power of up to 71.35 µW cm-2. Under medium humidity (50% RH) at low temperature (-20 °C), it provides an open-circuit voltage of 1.11 V and a short-circuit current of 15 µA cm-2.

Bioinspired ion channel receptor based on hygroelectricity for precontact sensing of living organism.

Tactile sensors play an important role in human-machine interaction (HMI). Compared to contact tactile sensing, which leaves physical hardware vulnerable to wear and tear, proximity sensing is better at reacting to remote events before physical contact. The apteronotus albifrons possess ion channel receptors for remote surroundings perception. Inspired by the relevant ion channel structure and self-powered operation mode, we designed a new proximity sensor with ion rectification characteristics and self-powered capability. This bio-inspired ion channel receptor exploits the hygroelectric effect to convert the humidity information into a series of current signals when the living organism approaches, and it is insensitive to non-aquatic non-organisms. The sensor offers high sensitivity (2.3 mm-1), a suitable range (0-10 mm) for close object detection, fast response (0.3 s), and fast recovery (2.5 s). The unique combination of bio-sensitivity, non-contact detection characteristics, and humidity-based power generation capabilities enriches the functionality of future HMI electronics. As a proof of concept, the sensor has been successfully applied in different scenarios such as human health management, early warning systems, non-contact switches to prevent virus transmission, object recognition, and finger trajectory detection.

Prosthetic finger for fingertip tactile sensing via flexible chromatic optical waveguides.

Building prosthetics indistinguishable from human limbs to accurately receive and transmit sensory information to users not only promises to radically improve the lives of amputees, but also shows potential in a range of robotic applications. Currently, a mainstream approach is to embed electrical or optical sensors with force/thermal sensing functions on the surface or inside of prosthetic fingers. Compared with electrical sensing technologies, tactile sensors based on stretchable optical waveguides have the advantages of easy fabrication, chemical safety, environmental stability, and compatibility with prosthetic structural materials. However, so far, research has mainly focused on the perception of finger joint motion or external press, and there is still a lack of study on optical sensors with fingertip tactile capabilities (such as texture, hardness, slip detection, etc.). Here we report a 3D printing prosthetic finger with flexible chromatic optical waveguides implanted at the fingertip. The finger achieves distributed displacement/force sensing detection, and exhibits high sensitivity, fast response and good stability. The finger can be used to conduct active sensory experiments, and the detection parameters include object contour, hardness, slip direction and speed, temperature, etc. Finally, exploratory research on identifying and manipulating objects is carried out with this finger. The developed prosthetic finger can artificially recreate touch perception and realize complex functions such as note-writing analysis and braille recognition.

Histology segmentation using active learning on regions of interest in oral cavity squamous cell carcinoma.

In digital pathology, deep learning has been shown to have a wide range of applications, from cancer grading to segmenting structures like glomeruli. One of the main hurdles for digital pathology to be truly effective is the size of the dataset needed for generalization to address the spectrum of possible morphologies. Small datasets limit classifiers' ability to generalize. Yet, when we move to larger datasets of whole slide images (WSIs) of tissue, these datasets may cause network bottlenecks as each WSI at its original magnification can be upwards of 100 000 by 100 000 pixels, and over a gigabyte in file size. Compounding this problem, high quality pathologist annotations are difficult to obtain, as the volume of necessary annotations to create a classifier that can generalize would be extremely costly in terms of pathologist-hours. In this work, we use Active Learning (AL), a process for iterative interactive training, to create a modified U-net classifier on the region of interest (ROI) scale. We then compare this to Random Learning (RL), where images for addition to the dataset for retraining are randomly selected. Our hypothesis is that AL shows benefits for generating segmentation results versus randomly selecting images to annotate. We show that after 3 iterations, that AL, with an average Dice coefficient of 0.461, outperforms RL, with an average Dice Coefficient of 0.375, by 0.086.

Sustainable power generation for at least one month from ambient humidity using unique nanofluidic diode.

The continuous energy-harvesting in moisture environment is attractive for the development of clean energy source. Controlling the transport of ionized mobile charge in intelligent nanoporous membrane systems is a promising strategy to develop the moisture-enabled electric generator. However, existing designs still suffer from low output power density. Moreover, these devices can only produce short-term (mostly a few seconds or a few hours, rarely for a few days) voltage and current output in the ambient environment. Here, we show an ionic diode-type hybrid membrane capable of continuously generating energy in the ambient environment. The built-in electric field of the nanofluidic diode-type PN junction helps the selective ions separation and the steady-state one-way ion charge transfer. This directional ion migration is further converted to electron transportation at the surface of electrodes via oxidation-reduction reaction and charge adsorption, thus resulting in a continuous voltage and current with high energy conversion efficiency.

[Application of Narcotrend-assisted anesthesia in-depth monitor during escharectomy and skin transplantation in burn patients with target-controlled infusion of remifentanil hydrochloride and propofol].

OBJECTIVE: To evaluate the feasibility and efficacy of Narcotrend (NT) monitor in monitoring the depth of anesthesia in severely burned patients with target-controlled infusion (TCI) of remifentanil hydrochloride and propofol during perioperative period. METHODS: Eighty patients with severe burn hospitalized from February to November 2011, to whom eschar excision was performed within one week after injury, were enrolled. They were classified into II to III grade according to the American Society of Anesthetists classification, and their total burn area ranged from 31% to 50%TBSA, or full-thickness burn area from 11% to 20% TBSA. Patients were divided into trial group (monitoring depth of anesthesia with routine method and NT monitor) and control group (monitoring depth of anesthesia with routine method) according to the random number table, with 40 cases in each group. All patients received TCI of remifentanil hydrochloride and propofol to induce and maintain anesthesia. During the operation, the anesthesia level of NT monitor used in the trial group was maintained from grade D1 to E0, while the fluctuation of mean arterial pressure (MAP) and heart rate of patients in control group was maintained around the basic values within a range of 20%, and on the basis of which, concentrations of two narcotics were adjusted. Concentrations of remifentanil hydrochloride and propofol during maintenance of anesthesia were recorded. The duration from drug withdrawal to waking from anesthesia (including the duration from drug withdrawal to eye opening by calling and the duration from drug withdrawal to orientation recovery) of patients was recorded. Values of MAP and heart rate at admission into the operation room, loss of consciousness, 2 min after intubation, before operation, 2, 15, and 30 min after the beginning of operation, and the end of operation were recorded. The prediction probability (P(k)) of NT stage (NTS) and NT index (NTI) in trial group, and that of MAP and heart rate in control group for two durations from drug withdrawal to waking form anesthesia were recorded. The administration of vasoactive drugs and intraoperative awareness of patients in two groups were recorded. Data were processed with t test, analysis of variance, and chi-square test, and the relationship between NTS, NTI, MAP, heart rate and their corresponding P(k) for the duration from drug withdrawal to orientation recovery was processed with Spearman correlation analysis. RESULTS: Maintained target effect-site concentration of remifentanil hydrochloride and target plasma concentration of propofol of patients were obviously lower in trial group [(2.62 ± 0.35) ng/mL, (3.84 ± 0.22) µg/mL] than in control group [(2.95 ± 0.21) ng/mL, (4.16 ± 0.31) µg/mL, with t values respectively -5.113 and -5.324, P values all below 0.01]. The duration from drug withdrawal to eye opening by calling and the duration from drug withdrawal to orientation recovery were obviously shorter in trial group [(10.2 ± 0.7) min, (11.1 ± 1.0) min] than in control group [(11.3 ± 1.0) min, (13.1 ± 0.7) min, with t values respectively -5.740 and -10.806, P values all below 0.01]. The MAP (except for 2 min after intubation) and the heart rate of patients in both groups were lower at the time points from loss of consciousness to the end of operation than at the time of entering operation room (with F values respectively 12.074, 36.425, P values all below 0.01 in trial group and F values respectively 21.776, 35.759, P values all below 0.01 in control group). The statistically significant difference between two groups in MAP level was only observed at the time of loss of consciousness (t = 3.985, P < 0.01). MAP level was close in two groups at other time points. Heart rates of patients in two groups were close during perioperative period. P(k) values of NTS and NTI for the duration from drug withdrawal to eye opening by calling (0.937 ± 0.025, 0.899 ± 0.049) were obviously higher than those of MAP and heart rate for this duration (0.579 ± 0.057, 0.536 ± 0.039, F = 900.337, P < 0.01). P(k) values of NTS and NTI for the duration from drug withdrawal to the orientation recovery (0.901 ± 0.031, 0.868 ± 0.046) were significantly higher than those of MAP and heart rate for this duration (0.532 ± 0.060, 0.483 ± 0.044, F = 890.895, P < 0.01). NTS, NTI, MAP, and heart rate were respectively negative, positive, positive and positive in correlation with their P(k) values for the duration from drug withdrawal to the orientation recovery (with r values from -0.734 to 0.682, P values all below 0.01). There was no statistically significant difference between two groups in administration of vasoactive drugs. No intraoperative awareness occurred. CONCLUSIONS: Application of Narcotrend monitor in monitoring the depth of anesthesia in severely burned patients during perioperative period with TCI of remifentanil hydrochloride and propofol is beneficial to reducing dosage of narcotics and shortening duration of recovery from anesthesia, and it can accurately predict the level of consciousness of patients at the time of withdrawal of anesthesia.