High-Performance and Stable Colloidal Quantum Dots Imager via Energy Band Engineering.

Solution-processed colloidal quantum dot (CQD) photodiodes are compatible for monolithic integration with silicon-based readout circuitry, enabling ultrahigh resolution and ultralow cost infrared imagers. However, top-illuminated CQD photodiodes for longer infrared imaging suffer from mismatched energy band alignment between narrow-bandgap CQDs and the electron transport layer. In this work, we designed a new top-illuminated structure by replacing the sputtered ZnO layer with a SnO2 layer by atomic layer deposition. Benefiting from matched energy band alignment and improved heterogeneous interface, our top-illuminated CQD photodiodes achieve a broad-band response up to 1650 nm. At 220 K, these SnO2-based devices exhibit an ultralow dark current density of 3.5 nA cm-2 at -10 mV, reaching the noise limit for passive night vision. The detectivity is 4.1 × 1012 Jones at 1530 nm. These SnO2-based devices also demonstrate exceptional operation stability. By integrating with silicon-based readout circuitry, our CQD imager realizes water/oil discrimination and see-through smoke imaging.

What can we learn from a Chinese social media used by glaucoma patients?

PURPOSE: Our study aims to discuss glaucoma patients' needs and Internet habits using big data analysis and Natural Language Processing (NLP) based on deep learning (DL). METHODS: In this retrospective study, we used web crawler technology to crawl glaucoma-related topic posts from the glaucoma bar of Baidu Tieba, China. According to the contents of topic posts, we classified them into posts with seeking medical advice and without seeking medical advice (social support, expressing emotions, sharing knowledge, and others). Word Cloud and frequency statistics were used to analyze the contents and visualize the keywords of topic posts. Two DL models, Bidirectional Long Short-Term Memory (Bi-LSTM) and Bidirectional Encoder Representations from Transformers (BERT), were trained to identify the posts seeking medical advice. The evaluation matrices included: accuracy, F1 value, and the area under the ROC curve (AUC). RESULTS: A total of 10,892 topic posts were included, among them, most were seeking medical advice (N = 7071, 64.91%), and seeking advice regarding symptoms or examination (N = 4913, 45.11%) dominated the majority. The following were searching for social support (N = 2362, 21.69%), expressing emotions (N = 497, 4.56%), and sharing knowledge (N = 527, 4.84%) in sequence. The word cloud analysis results showed that ocular pressure, visual field, examination, and operation were the most frequent words. The accuracy, F1 score, and AUC were 0.891, 0.891, and 0.931 for the BERT model, 0.82, 0.821, and 0.890 for the Bi-LSTM model. CONCLUSION: Social media can help enhance the patient-doctor relationship by providing patients' concerns and cognition about glaucoma in China. NLP can be a powerful tool to reflect patients' focus on diseases. DL models performed well in classifying Chinese medical-related texts, which could play an important role in public health monitoring.

High-Performance Colloidal Quantum Dot Photodiodes via Suppressing Interface Defects.

PbS colloidal quantum dot (CQD) infrared photodiodes have attracted wide attention due to the prospect of developing cost-effective infrared imaging technology. Presently, ZnO films are widely used as the electron transport layer (ETL) of PbS CQDs infrared photodiodes. However, ZnO-based devices still suffer from the problems of large dark current and low repeatability, which are caused by the low crystallinity and sensitive surface of ZnO films. Here, we effectively optimized the device performance of PbS CQDs infrared photodiode via diminishing the influence of adsorbed H2O at the ZnO/PbS CQDs interface. The polar (002) ZnO crystal plane showed much higher adsorption energy of H2O molecules compared with other nonpolar planes, which could reduce the interface defects induced by detrimentally adsorbed H2O. Based on the sputtering method, we obtained the [002]-oriented and high-crystallinity ZnO ETL and effectively suppressed the adsorption of detrimental H2O molecules. The prepared PbS CQDs infrared photodiode with the sputtered ZnO ETL demonstrated lower dark current density, higher external quantum efficiency, and faster photoresponse compared with the sol-gel ZnO device. Simulation results further unveiled the relationship between interface defects and device dark current. Finally, a high-performance sputtered ZnO/PbS CQDs device was obtained with a specific detectivity of 2.15 × 1012 Jones at -3 dB bandwidth (94.6 kHz).

Large-area flexible colloidal-quantum-dot infrared photodiodes for photoplethysmogram signal measurements.

Epitaxially grown photodiodes are the foundation of infrared photodetection technology; however, their rigid structure and limited area scaling limit their use in advanced applications. Colloidal-quantum-dot (CQD) infrared photodiodes have increased active areas through solution processing, and are thus potential candidates for large-area flexible photodetection, but these large-area photodiodes have disadvantages such as large dark current density, poor homogeneity, and poor stability. Therefore, this study established a fabrication strategy for large-area flexible CQD photodiodes that involves introducing polyimide to CQD ink to improve CQD passivation, monodisperse ink persistence, and film morphology. The resulting CQD photodiodes exhibited reduced dark current density and improved homogeneity and work stability. Furthermore, the as-prepared photodiodes exhibited a detectivity (D*) of greater than 1013 Jones, which was higher than other reported CQD photodetectors. The CQD photodiodes developed in this study can be used for wearable photoplethysmogram (PPG) signal measurement under ambient light at reduced cost and power consumption.

Influence of ball milling process on microstructure, mechanical and thermal expansion properties of ZrMgMo3O12/Al-40Si composites.

In this study, ZrMgMo3O12/Al-40Si (ZMMO/Al-40Si) composites with 15 wt% ZrMgMo3O12 were fabricated by ball milling-vacuum hot pressing (VHP) processes. The effect of ball milling processes on the microstructure, compressive properties and coefficient of thermal expansion (CTE) of the composites were investigated. It is found that ball milling treatments of mixed ZMMO/Al-40Si powders refine the particles of ZMMO reinforcements and primary Si in ZMMO/Al-40Si composites and improve the distribution of ZMMO reinforcements in α-Al matrix, resulting in the increase of the compressive strength and the decrease of the CTE of ZMMO/Al-40Si composites. The highest compressive yield strength of 430.82 MPa and the lowest CTEs of 5.8 × 10-6/°C (RT - 400 °C) are obtained after ball milling for 8 h at 250 rpm, increasing by 145.9% and decreasing by 61.3% respectively compared with the compressive yield strength and CTE of Al-40Si alloy. Among the reinforcements commonly used in aluminum matrix composites, ZMMO reinforcement has the highest reduction efficiency for CTE of ZMMO/Al-40Si composite. The application of high-energy ball milling to refine the microstructure is a promising method that can simultaneously increase the strength and reduce the CTEs of ZMMO/Al-40Si composites.

Induction of apoptosis in human promyelocytic leukemia HL60 cells by panaxynol and panaxydol.

Panaxynol and panaxydol are naturally occurring polyacetylenes, isolated from the lipophilic fractions of Panax notoginseng, that exert anti-proliferative effects against malignant cells. However, to the best of our knowledge, no study concerning the inhibitory effects of the two polyacetylenes on cell growth of human promyelocytic leukemia cells has been reported. In this paper, we examined the antiproliferation and proapoptotic effects of panaxynol and panaxydol on HL60 cells and investigated their mechanism of action. Cell growth inhibition of panaxynol and panaxydol were determined by trypan blue dye exclusion assays. Apoptosis of cells was revealed by morphological observation, analysis for nuclear DNA distribution and by annexin V-FITC/ PI staining using flow cytometry. It was found that panaxynol and panaxydol markedly inhibited proliferation of HL60 cells in a time- and dose-dependent manner via an apoptotic pathway. In concern with these findings, Western blot analysis showed proteolytic activation of PKCδ, caspase-3 activation and cleavage of poly (ADP [adenosine diphosphate]-ribose) polymerase in HL60 cells treated by panaxynol and panaxydol. In conclusion, panaxynol and panaxydol have profound effects on growth and apoptosis of HL60 cells, suggesting those substances are worthy of further exploration as potential anti-cancer agents.

Spinning micropipette liquid emulsion generator for single cell whole genome amplification.

Many on-chip approaches that use flow-focusing to pinch the continuous aqueous phase into droplets have become the most popular methods that provide monodisperse emulsion droplets. However, not every lab can easily adapt a microfluidic workflow into their familiar protocols. We develop an off-chip approach, spinning micro-pipette liquid emulsion (SiMPLE) generator, to produce highly stable monodisperse water-in-oil emulsions using a moving micropipette to disperse the aqueous phase in an oil-filled microcentrifuge tube. This method provides a simple way to produce picoliter-size droplets in situ with no dead volume during emulsification. With SiMPLE, single-cell emulsion whole genome amplification was performed to demonstrate that this novel method can seamlessly be integrated with experimental operations and supplies that most researchers are familiar with. The SiMPLE generator has effectively lowered the technical difficulties in applications relying on emulsion droplets.

Design, preparation, and selection of DNA-encoded dynamic libraries.

We report a method for the preparation and selection of DNA-encoded dynamic libraries (DEDLs). The library is composed of two sets of DNA-linked small molecules that are under dynamic exchange through DNA hybridization. Addition of the protein target shifted the equilibrium, favouring the assembly of high affinity bivalent binders. Notably, we introduced a novel locking mechanism to stop the dynamic exchange and "freeze" the equilibrium, thereby enabling downstream hit isolation and decoding by PCR amplification and DNA sequencing. Our DEDL approach has circumvented the limitation of library size and realized the analysis and selection of large dynamic libraries. In addition, this method also eliminates the requirement for modified and immobilized target proteins.