Metal-Organic Framework Materials in Perovskite Solar Cells: Recent Advancements and Perspectives.

Organic-inorganic hybrid perovskite solar cells (PSCs) are among the most promising candidates for the next generation of photovoltaic devices because of the significant increase in their power conversion efficiency (PCE) from less than 10% to 25.7% in past decade. The metal-organic framework (MOF) materials owing to their unique properties, such as large specific surface area, abundant binding sites, adjustable nanostructures, and synergistic effects, are used as additives or functional layers to enhance the device performance and long-term stability of PSCs. This review focuses on the recent advancements in the applications of MOFs as/in different functional layers of PSCs. The photovoltaic performance, impact, and advantages of MOF materials integrated into the perovskite absorber, electron transport layer, hole transport layer, and interfacial layer are reviewed. In addition, the applicability of MOFs to mitigate leakage of Pb2+ from halide perovskites and corresponding devices is discussed. This review concludes with the perspectives on further research directions for employing MOFs in PSCs.

Lateral flow immunoassay for proteins.

Protein biomarkers are useful for disease diagnosis. Identification thereof using in vitro diagnostics such as lateral flow immunoassays (LFIAs) has attracted considerable attention due to their low cost and ease of use especially in the point of care setting. Current challenges, however, do remain with respect to material selection for each component in the device and the synergistic integration of these components to display detectable signals. This review explores the principle of LFIA for protein biomarkers, device components including biomaterials and labeling methods. Medical applications and commercial status are examined as well. This review highlights critical methodologies in the development of new LFIAs and their role in advancing healthcare worldwide.

Evaluating the impact of writing surface and configuration on muscle activation level during a handwriting task: An exploratory study.

BACKGROUND: Tablets are ubiquitous in workplaces and schools. However, there have been limited studies investigating the effect tablets have on the body during digital writing activities. OBJECTIVE: This study investigated the biomechanical impact of writing interface design (paper, whiteboard, and tablet) and orientation (horizontal, 45°, and vertical) on tablet users. METHODS: Fourteen adults (7 male, 7 female) participated in a study during which they performed simple writing tasks. Surface electromyography (sEMG) sensors were used to measure upper extremity muscle activation. RESULTS: Results indicate that the effects of writing surface type were most pronounced in forearm muscle activation. Specifically, in the extensor carpi radialis (ECR), where muscle activity was lower on the tablet PC surface. The effects of writing configuration were prominent in the shoulder and forearm. The activation of the flexor carpi ulnaris (FCU) and trapezius muscles was significantly lower in the 45° configuration. An exception to the efficacy of this configuration was the anterior deltoid muscle, which exhibited the lowest muscle activity in the horizontal orientation. CONCLUSIONS: Tablet surface and the 45° configuration resulted in the lowest muscle activation levels. Future studies should include longer experiment duration to investigate the effects of continuous writing.

High-efficiency (>20%) planar carbon-based perovskite solar cells through device configuration engineering.

Carbon-based perovskite solar cells (C-PSCs) have attracted widespread research interest because of their excellent stability. However, the power conversion efficiency (PCE) of C-PSCs, especially planar C-PSCs, lags far behind the certified efficiency (25.5%) of metal-based PSCs. The simple architecture of planar C-PSCs imparts stringent requirements for device configuration. In this study, we fabricated high-performance planar C-PSCs through device configuration engineering in terms of the perovskite active layer and carbon electrode. Through the combination of component and additive engineering, the crystallization and absorption profiles of perovskite active layer have been improved, which afforded sufficient photogenerated carriers and decreased nonradiative recombination. Furthermore, the mechanical and physical properties of carbon electrode were evaluated comprehensively to regulate the back-interface contact. Based on the compromise of the flexibility and conductivity of carbon film, an excellent back-interface contact has been formed, which promoted fast interface charge transfer, thereby decreasing interface recombination and improving carrier collection efficiency. Finally, the as-prepared devices achieved a remarkable PCE of up to 20.04%, which is a record-high value for planar C-PSCs. Furthermore, the as-prepared devices exhibited excellent long-term stability. After storage for 1000 h at room temperature and 25% relative humidity without encapsulation, the as-prepared device retained 94% of its initial performance.

A Rational Approach to Understanding and Evaluating Responsive Neurostimulation.

Closed-loop brain stimulation is increasingly used in level 4 epilepsy centers without an understanding of how the device behaves on a daily basis. This lack of insight is a barrier to improving closed-loop therapy and ultimately understanding why some patients never achieve seizure reduction. We aimed to quantify the accuracy of closed-loop seizure detection and stimulation on the RNS device through extrapolating information derived from manually reviewed ECoG recordings and comprehensive device logging information. RNS System event logging data were obtained, reviewed, and analyzed using a custom-built software package. A weighted-means methodology was developed to adjust for bias and incompleteness in event logs and evaluated using Bland-Altman plots and Wilcoxon signed-rank tests to compare adjusted and non-weighted (standard method) results. Twelve patients implanted for a mean of 21.5 (interquartile range 13.5-31) months were reviewed. The mean seizure frequency reduction post-RNS implantation was 40.1% (interquartile range 0-96.2%). Three primary levels of event logging granularity were identified (ECoG recordings: 3.0% complete (interquartile range 0.3-1.8%); Event Lists: 72.9% complete (interquartile range 44.7-99.8%); Activity Logs: 100% complete; completeness measured with respect to Activity Logs). Bland-Altman interpretation confirmed non-equivalence with unpredictable differences in both magnitude and direction. Wilcoxon signed rank tests demonstrated significant (p < 10-6) differences in accuracy, sensitivity, and specificity at >5% absolute mean difference for extrapolated versus standard results. Device behavior logged by the RNS System should be used in conjunction with careful review of stored ECoG data to extrapolate metrics for detector performance and stimulation.

Voltage-Tunable Dual Image of Electrostatic Force-Assisted Dispensing Printed, Tungsten Trioxide-Based Electrochromic Devices with a Symmetric Configuration.

Electrostatic force-assisted dispensing (EFAD)-printed tungsten trioxide (WO3)-based electrochromic devices (ECDs) displaying a dual image depending on the applied voltage are demonstrated. We first print WO3 via EFAD printing, in which the width of the printed lines can be tuned by adjusting the printing speed. The performance of the ECDs is characterized while varying the thickness of the printed WO3 film. It is determined that ∼550 nm thick WO3 is the optimal film considering maximum transmittance contrast (ΔTmax), device dynamic responses, efficiency, and long-term coloration/bleaching cyclic stability. More significantly, the coloration of the devices in this work can alternatively appear due to the use of electrolyte-soluble anodic species (here, dimethyl ferrocene, dmFc), for which WO3 films should be deposited on both electrodes and a part of the electrodes should be exposed to the electrolyte for the oxidation of dmFc. To take advantage of such features of the devices, we successfully demonstrate EFAD-printed, flexible WO3 ECDs alternately displaying a dual image, which is expected to have high potential as a functional component of printed electronics.

Closed-Loop Brain Stimulation for Drug-Resistant Epilepsy: Towards an Evidence-Based Approach to Personalized Medicine.

Closed-loop brain stimulation is one of the few treatments available for patients who are ineligible for traditional surgical resection of the epileptogenic zone, due to having generalized epilepsy, multifocal epilepsy, or focal epilepsy localized to an eloquent brain region. Due to its clinical efficacy and potential to delivery personalized therapy based on an individual's own intracerebral electrophysiology, this treatment is becoming an important part of clinical practice, despite a limited understanding of how to program detection and stimulation parameters for optimal, patient-specific benefit. To bring this challenge into focus, we review the evolution of neural stimulation for epilepsy, provide a technical overview of the RNS System (the only FDA-approved closed-loop device), and discuss the major challenges of working with a closed-loop device. We then propose an evidence-based solution for individualizing therapy that is driven by a bottom-up informatics approach.

A Ladder-type Heteroheptacene 12H-Dithieno[2',3':4,5]thieno[3,2-b:2',3'-h]fluorene Based D-A Copolymer with Strong Intermolecular Interactions toward Efficient Polymer Solar Cells.

Ladder-type electron-donating units for D-A copolymers applied in polymer solar cells usually comprise multiple tetrahedral carbon bridges bonded with out-of-plane alkyl chains for desirable solubility for device processing. However, molecular packing of resultant copolymers in the solid state and charge transport within devices are also impeded in spite of with multiple fused aromatic backbones. To mitigate this issue, a structurally well-defined ladder-type electron-donating heteroheptacene, 12H-dithieno[2',3':4,5]thieno[3,2-b:2',3'-h]fluorene (DTTF) with an extended conjugated backbone and a single tetrahedral carbon bridge attached with two bulky alkyl chains was designed and synthesized. The copolymerization of DTTF with 4,7-bis(4-hexylthiophen-2-yl)benzo[c][1,2,5]thiadiazole (DTBT) afforded a soluble D-A copolymer (PDTTF-DTBT) with a medium optical band gap of 1.72 eV and low-lying HOMO level at -5.36 eV. PDTTF-DTBT unprecedentedly exhibits strong intermolecular stacking ability and presents preferential face-on orientation on both ZnO and PEDOT:PSS layers. The improved packing order and appropriate phase separation of both the copolymer and PC71BM in the bulk heterojunction blend on the ZnO layer over on the PEDOT:PSS layer lead to much improved power conversion efficiency of ∼8.2% in the inverted solar cell device, among the highest for reported ladder-type D-A copolymers. The research demonstrates that it is an effective method to incorporate a single tetrahedral carbon bridge to the molecular center of a ladder-type heteroacene with heavily extended π-conjugation to prepare D-A copolymers toward highly efficient PSCs.

Application and optimization of field psychological emergency rescue chest / 医疗卫生装备

Objective To optimize the design of the field psychological emergency rescue chest.Methods The deficiencies of the chest were summarized during the drilling and actual application of the psychological rescue unit,and some optimization countermeasures were put forward accordingly.Results The chest was optimized from the aspects of selection of chest body, internal and external layout as well as equipped devices.Conclusion The optimized chest can better meet the needs of the disaster emergency rescue.