Optic nerve Hemangioblastoma with bilateral frontal lobe Oedema: a case report.

BACKGROUND: Hemangioblastomas are rare benign tumours that are most commonly detected in the subtentorium or spinal cord. Optic nerve hemangioblastoma is very rare and is most commonly associated with Von Hippel-Lindau (VHL) syndrome. CASE PRESENTATION: Here, we report a case of hemangioblastoma of the optic nerve with bilateral frontal lobe oedema without VHL syndrome, which has not yet been reported. A 51-year-old woman presented with progressive and painless deteriorating vision in the left eye. Magnetic resonance imaging showed a mass at the back of the left orbital optic nerve. Endoscopic-assisted intraorbital tumour resection was performed successfully. The pathological diagnosis was left optic nerve hemangioblastoma. CONCLUSIONS: This is the first reported case of optic nerve hemangioblastoma (HBL) with bilateral frontal lobe oedema.

Fabrication of Flexible Microneedle Array Electrodes for Wearable Bio-Signal Recording.

Laser-direct writing (LDW) and magneto-rheological drawing lithography (MRDL) have been proposed for the fabrication of a flexible microneedle array electrode (MAE) for wearable bio-signal monitoring. Conductive patterns were directly written onto the flexible polyethylene terephthalate (PET) substrate by LDW. The microneedle array was rapidly drawn and formed from the droplets of curable magnetorheological fluid with the assistance of an external magnetic field by MRDL. A flexible MAE can maintain a stable contact interface with curved human skin due to the flexibility of the PET substrate. Compared with Ag/AgCl electrodes and flexible dry electrodes (FDE), the electrode-skin interface impedance of flexible MAE was the minimum even after a 50-cycle bending test. Flexible MAE can record electromyography (EMG), electroencephalography (EEG) and static electrocardiography (ECG) signals with good fidelity. The main features of the dynamic ECG signal recorded by flexible MAE are the most distinguishable with the least moving artifacts. Flexible MAE is an attractive candidate electrode for wearable bio-signal monitoring.

Enhanced Performance of Triboelectric Nanogenerators and Sensors via Cold Spray Particle Deposition.

In this study, a high-performance triboelectric nanogenerator (TENG) is developed based on cold spray (CS) deposition of composite material layers. Composite layers were fabricated by cold spraying of micron-scale tin (Sn) particles on aluminum (Al) and polytetrafluoroethylene (PTFE) films, which led to improved TENG performance owing to functionalized composite layers as friction layers and electrodes, respectively. As-sprayed tin composite layers not only enhanced the flow of charges by strong adhesion to the target layer but also formed a nano-microstructure on the surface of the layers, thereby increasing the surface area during friction. More importantly, the electricity generation performance was improved more than 6 times as compared to the TENG without CS deposition on it. From parametric studies, the TENG using the cold-sprayed composite layer produced an electrical potential of 1140 V for a simple structure with a 25.4 × 25.4 mm2 contact area. We also optimize the geometry and fabrication process of the TENG to increase the manufacturing efficiency while reducing the processing cost. The resultant sprayed layers and structures exhibited sustainable robustness by showing consistent electrical performance after the mechanical adhesion test. The proposed manufacturing approach is also applicable for processing three-dimensional (3D) complex layers owing to the technological convergence of a cold spray gun attached to a robotic arm, which makes possible to fabricate the 3D TENG. To elaborate, a composite layer having the shape of a 3D ball is produced, and the exercise status of the ball is monitored in real-time. The fabricated 3D ball using the TENG transmitted a distinguishable signal in real-time according to the state of the ball. The proposed TENG sensing system can be utilized as a self-powered sensor without the need of a battery, amplifier, and rectifier. The results of this study can potentially provide insights for the practical material design and fabrication of self-powered TENG systems.

A Preliminary Study of Personalized Head CT Scan in Pediatric Patients.

OBJECTIVES: In the present study, we introduced a practical approach to quantify organ-specific radiation doses and investigated whether low-dose head circumference (HC)-based protocols for non-enhanced head computed tomography (CT) could reduce organs-specific radiation dose in pediatric patients while maintaining high image quality. METHODS: A total of 83 pediatric patients were prospectively recruited. Without limits to the HC, 15 patients were selected as a convention group (CON group) and underwent non-enhanced head CT scan with standard-dose protocols (tube current-time products of 250mAs). Low-dose group (LD group), including remaining 68 pediatrics were divided into 3 subgroups based on the HC: 54.1-57.0 cm for LD200mAs group (HC-based protocols of 200mAs), 51.1-54.0 cm for LD150mAs group (HC-based protocols of 150mAs), 48.1-51.0 cm for LD100mAs group (HC-based protocols of 100mAs). Subjective and objective image quality was evaluated and measured by 2 experienced radiologists. Radimetrics was used to calculate organs-specific radiation dose, including the brain, eye lenses, and salivary glands. RESULTS: In CON250mAs group, radiation doses in the brain and salivary glands were conversely correlated with HC, and pediatric patients with smaller HC received higher organs-specific radiation dose. Reducing tube current-time product from 250 to 100mAs could significantly reduce the organ-specific radiation dose. The subjective image quality score ≥ 3.0 is acceptable for diagnosis purposes. The signal to noise ratio (SNR) and the contrast to noise ratio (CNR) of bilateral thalamus and centrum semiovale in 3 LD subgroups were not statistically different compared with the CON group. CONCLUSION: Our research indicated that low-dose HC-based protocols of non-enhanced head CT scan can evidently reduce the organ-specific radiation doses, while maintaining high image quality. HC can serve as a vital tool to guide personalized low-dose head CT scan for pediatric patients.

Enhancement of patterned triboelectric output performance by an interfacial polymer layer for energy harvesting application.

Efficaciously scavenging waste mechanical energy from the environment is an emerging field in the self-powered and self-governing electronics systems which solves battery limitations. It demonstrates enormous potential in various fields such as wireless devices, vesture, and portable electronic devices. Different surface textured PET triboelectric nanogenerators (TENGs) were developed by the laser pattern method in the previous work, with the line textured TENG device showing improved performance due to a larger surface contact area. Here, a polyethylene oxide (PEO) and polyvinyl alcohol (PVA) coated line patterned PET-based TENG was developed for the conversion of mechanical energy into useful electric energy. The PEO layer boosted the TENG output to 4 times higher than that of the PA6-laser patterned PET TENG device (our previous report) and 2-fold higher than that of a pristine line patterned TENG. It generated an open-circuit voltage, short circuit current, and instantaneous power density of 131 V, 2.32 µA, and 41.6 µW cm-2, respectively. The as-fabricated device was tested for 10 000 cycles for reliability evaluation, which shows no significant performance degradation. In addition, the device was deployed to power 10 LEDs with high intensity. Thus, this device can be used for ambient mechanical energy conversion and to power micro and nano-electronic devices.

Isoflurane-Induced Burst Suppression Is a Thalamus-Modulated, Focal-Onset Rhythm With Persistent Local Asynchrony and Variable Propagation Patterns in Rats.

Background: Inhalational anesthetic-induced burst suppression (BS) is classically considered a bilaterally synchronous rhythm. However, local asynchrony has been predicted in theoretical studies and reported in patients with pre-existing focal pathology. Method: We used high-speed widefield calcium imaging to study the spatiotemporal dynamics of isoflurane-induced BS in rats. Results: We found that isoflurane-induced BS is not a globally synchronous rhythm. In the neocortex, neural activity first emerged in a spatially shifting, variably localized focus. Subsequent propagation across the whole cortex was rapid, typically within <100 milliseconds, giving the superficial resemblance to global synchrony. Neural activity remained locally asynchronous during the bursts, forming complex recurrent propagating waves. Despite propagation variability, spatial sequences of burst propagation were largely preserved between the hemispheres, and neural activity was highly correlated between the homotopic areas. The critical role of the thalamus in cortical burst initiation was demonstrated by using unilateral thalamic tetrodotoxin injection. Conclusion: The classical impression that anesthetics-induced BS is a state of global brain synchrony is inaccurate. Bursts are a series of shifting local cortical events facilitated by thalamic projection that unfold as rapid, bilaterally asynchronous propagating waves.

A 3D printed smartphone optosensing platform for point-of-need food safety inspection.

The deficiency in rapid and in-field detection methods and portable devices that are reliable, easy-to-use, and low cost, results in the difficulties to uphold the high safety standards in China. In this study, we introduce a rapid and cost-effective smartphone-based method for point-of-need food safety inspection, which employs aptamer-conjugated AuNPs as the colorimetric indicator, and a battery-powered optosensing accessory attached to the camera of a smartphone for transmission images capture. A user-friendly and easy-to-use Android application is developed for automatic digital image processing and result reporting. Streptomycin (STR) is selected as the proof-of-concept target, and its specific quantitation can be realized with a LOD of 12.3 nM (8.97 µg kg-1) using the reported smartphone-based method. The quantitation of STR in honey, milk and tap water confirm the reliability and applicability of the reported method. The extremely high acceptance of smartphone in remote and metropolitan areas of China and ease-of-use of the reported method facilitate active food contaminant and toxicant screening, thus making the implementation of the whole food supply chain monitoring and surveillance possible and hence significantly improving the current Chinese food safety control system.

Effect of honeybee stinger and its microstructured barbs on insertion and pull force.

Worker honeybee is well-known for its stinger with microscopic backward-facing barbs for self-defense. The natural geometry of the stinger enables painless penetration and adhesion in the human skin to deliver poison. In this study, Apis cerana worker honeybee stinger and acupuncture microneedle (as a barbless stinger) were characterized by Scanning Electron Microscope (SEM). The insertion and pull process of honeybee stinger into rabbit skin was performed by a self-developed mechanical loading equipment in comparison with acupuncture needle. In order to better understand the insertion and pull mechanisms of the stinger and its barbs in human multilayer skin, a nonlinear finite element method (FEM) was conducted. Experimental results showed that the average pull-out force of the stinger was 113.50mN and the average penetration force was only 5.75mN. The average penetration force of the stinger was about one order of magnitude smaller than that of an acupuncture microneedle while the average pull-out force was about 70 times larger than that of an acupuncture microneedle. FEM results showed that the stress concentrations were around the stinger tip and its barbs during the insertion process. The barbs were jammed in and torn the skin during the pull process. The insertion force of the stinger was greatly minimized due to its ultrasharp stinger tip and barbs while the pull force was seriously enhanced due to the mechanical interlocking of the barbs in the skin. These excellent properties are mainly a result of optimal geometry evolved by nature. Such finding may provide an inspiration for the further design of improved tissue adhesives and micro-needles for painless transdermal drug delivery and bio-signal recording.