Dual-Adaptive Heterojunction Synaptic Transistors for Efficient Machine Vision in Harsh Lighting Conditions.

Photoadaptive synaptic devices enable in-sensor processing of complex illumination scenes, while second-order adaptive synaptic plasticity improves learning efficiency by modifying the learning rate in a given environment. The integration of above adaptations in one phototransistor device will provide opportunities for developing high-efficient machine vision system. Here, a dually adaptable organic heterojunction transistor as a working unit in the system, which facilitates precise contrast enhancement and improves convergence rate under harsh lighting conditions, is reported. The photoadaptive threshold sliding originates from the bidirectional photoconductivity caused by the light intensity-dependent photogating effect. Metaplasticity is successfully implemented owing to the combination of ambipolar behavior and charge trapping effect. By utilizing the transistor array in a machine vision system, the details and edges can be highlighted in the 0.4% low-contrast images, and a high recognition accuracy of 93.8% with a significantly promoted convergence rate by about 5 times are also achieved. These results open a strategy to fully implement metaplasticity in optoelectronic devices and suggest their vision processing applications in complex lighting scenes.

Experimental Study on Energy-Free Superhydrophobic Radiative Cooling Versatile Film with Enhanced Environmental Tolerance.

Clean, energy-free methods of cooling are an effective way to respond to the global energy crisis. To date, cooling materials using passive daytime radiative cooling (RC) technology have been applied in the fields of energy-efficient buildings, solar photovoltaic cooling, and insulating textiles. However, RC materials frequently suffer from comprehensive damage to their microstructure, resulting in the loss of their initial cooling effect in complex outdoor environments. Here, a superhydrophobic daytime passive RC porous film with environmental tolerance (SRCP film) was fabricated, which integrated strong solar reflectivity (approximately 90%), mid-infrared emissivity (approximately 0.97), and superhydrophobicity (water contact angle (WCA) of 160° and sliding angle of 3°). This study revealed that SRCP film had an average reflectivity of 14.3% higher than SiO2 particles in the 0.3-2.5 µm wavelength region, achieving a cooling effect of 13.2 °C in ambient conditions with a solar irradiance of 946 W·m-2 and a relative humidity of 74% due to the synergistic effect of effective solar reflection and thermal infrared emission. In addition, empirical results showed that the attained films possessed outstanding environmental tolerance, maintaining high WCA (156°), stable cooling effect (8.3 °C), and low SiO2 loss (less than 5.1%) after 30 consecutive days of UV irradiation and 14 days of corrosion with acidic and alkaline solutions. More importantly, this work could be flexibly prepared by various methods without the use of any fluorine-containing reagents, which greatly widens the practical application scope.

Charge-Localized Retention and Long-Term Memory Enabled by Cooperating Sterically Confined Molecular Crystallization with Spiro[fluorene-9,9'-xanthene]-Based Csp3-Hindrance.

Charge localization of memory materials plays a crucial role in the endurance and retention ability of organic nonvolatile memory, which is completely opposite from the charge delocalization of high-mobility materials. However, charge transfer of both though-space and through-bond based on molecular design principles still faces challenges. Herein, a nonplanar wide-bandgap semiconductor with Csp3-hindrance (DOCH3-DDPA-SFX) has been designed and synthesized. An effective crystallization effect of self-assembled two-dimensional nanosheets on charge trapping dynamics and kinetics is visualized by Kelvin probe force microscopy (KPFM). The trapped charges are localized completely on a single nanosheet, which has better charge trapping and retention properties than an amorphous film. Meanwhile, crystallization also greatly improves structure stability. Combining DFT theoretical calculations, the mechanisms of localization and long-term retention are discussed. The steric crystallization effects on the charge localization will guide the effective design of single-component semiconducting charge-memory materials by molecular assembly and aggregate control for high-performance organic memory.

Pseudo-transistors for emerging neuromorphic electronics.

Artificial synaptic devices are the cornerstone of neuromorphic electronics. The development of new artificial synaptic devices and the simulation of biological synaptic computational functions are important tasks in the field of neuromorphic electronics. Although two-terminal memristors and three-terminal synaptic transistors have exhibited significant capabilities in the artificial synapse, more stable devices and simpler integration are needed in practical applications. Combining the configuration advantages of memristors and transistors, a novel pseudo-transistor is proposed. Here, recent advances in the development of pseudo-transistor-based neuromorphic electronics in recent years are reviewed. The working mechanisms, device structures and materials of three typical pseudo-transistors, including tunneling random access memory (TRAM), memflash and memtransistor, are comprehensively discussed. Finally, the future development and challenges in this field are emphasized.

A Reconfigurable Optoelectronic Synaptic Transistor with Stable Zr-CsPbI3 Nanocrystals for Visuomorphic Computing.

Reconfigurable phototransistor memory attracts considerable attention for adaptive visuomorphic computing, with highly efficient sensing, memory, and processing functions integrated onto a single device. However, developing reconfigurable phototransistor memory remains a challenge due to the lack of an all-optically controlled transition between short-term plasticity (STP) and long-term plasticity (LTP). Herein, an air-stable Zr-CsPbI3 perovskite nanocrystal (PNC)-based phototransistor memory is designed, which is capable of broadband photoresponses. Benefitting from the different electron capture ability of Zr-CsPbI3 PNCs to 650 and 405 nm light, an artificial synapse and non-volatile memory can be created on-demand and quickly reconfigured within a single device for specific purposes. Owing to the optically reconfigurable and wavelength-aware operation between STP and LTP modes, the integrated blue feature extraction and target recognition can be demonstrated in a homogeneous neuromorphic vision sensor array. This work suggests a new way in developing perovskite optoelectronic transistors for highly efficient in-sensor computing.

Integrating wind-driven agitating blade into a floating photobioreactor to enhance fluid mixing and microalgae growth.

Aiming at optimizing the poor fluid mixing state in the traditional horizontal floating photobioreactors and reducing the high energy consumption and operational cost induced by electric-driven mixing, a novel floating photobioreactor with an embedded wind-driven agitating blade (WDAB-FPBR) was proposed in this study, which can effectively utilize both wind and wave energy for fluid mixing. The results show that the selected wind-driven agitating blade contributed to a decrement of 75.3% in mixing time and an increment of 87.5% in mass transfer coefficient, and meanwhile strengthened the fluid velocity along the light gradient. Owing to the enhanced fluid flow and mixing properties, an even distribution of algae cells was achieved in the WDAB floating photobioreactor, which resulted in an improvement of 140% in the photosynthesis efficiency of microalgae. From this, the biomass yield and carbon removal ratio showed an increment of 88.9% and 73.9%, respectively.

Low-power flexible organic memristor based on PEDOT:PSS/pentacene heterojunction for artificial synapse.

Organic synaptic memristors are of considerable interest owing to their attractive characteristics and potential applications to flexible neuromorphic electronics. In this work, an organic type-II heterojunction consisting of poly(3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT:PSS) and pentacene was adopted for low-voltage and flexible memristors. The conjugated polymer PEDOT:PSS serves as the flexible resistive switching (RS) layer, while the thin pentacene layer plays the role of barrier adjustment. This heterojunction enabled the memristor device to be triggered with low-energy RS operations (V < ± 1.0 V and I < 9.0 µA), and simultaneously providing high mechanical bending stability (bending radius of ≈2.5 mm, bending times = 1,000). Various synaptic properties have been successfully mimicked. Moreover, the memristors presented good potentiation/depression stability with a low cycle-to-cycle variation (CCV) of less than 8%. The artificial neural network consisting of this flexible memristor exhibited a high accuracy of 89.0% for the learning with MNIST data sets, even after 1,000 tests of 2.5% stress-strain. This study paves the way for developing low-power and flexible synaptic devices utilizing organic heterojunctions.

Clinical significance of cyclin-dependent kinase inhibitor 2C expression in cancers: from small cell lung carcinoma to pan-cancers.

BACKGROUND: Cyclin-dependent kinase inhibitor 2C (CDKN2C) was identified to participate in the occurrence and development of multiple cancers; however, its roles in small cell lung carcinoma (SCLC) remain unclear. METHODS: Differential expression analysis of CDKN2C between SCLC and non-SCLC were performed based on 937 samples from multiple centers. The prognosis effects of CDKN2C in patients with SCLC were detected using both Kaplan-Meier curves and log-rank tests. Using receiver-operating characteristic curves, whether CDKN2C expression made it feasible to distinguish SCLC was determined. The potential mechanisms of CDKN2C in SCLC were investigated by gene ontology terms and signaling pathways (Kyoto Encyclopedia of Genes and Genomes). Based on 10,080 samples, a pan-cancer analysis was also performed to determine the roles of CDKN2C in multiple cancers. RESULTS: For the first time, upregulated CDKN2C expression was detected in SCLC samples at both the mRNA and protein levels (p of Wilcoxon rank-sum test < 0.05; standardized mean difference = 2.86 [95% CI 2.20-3.52]). Transcription factor FOXA1 expression may positively regulate CDKN2C expression levels in SCLC. High CDKN2C expression levels were related to the poor prognosis of patients with SCLC (hazard ratio > 1, p < 0.05) and showed pronounced effects for distinguishing SCLC from non-SCLC (sensitivity, specificity, and area under the curve ≥ 0.95). CDKN2C expression may play a role in the development of SCLC by affecting the cell cycle. Furthermore, the first pan-cancer analysis revealed the differential expression of CDKN2C in 16 cancers (breast invasive carcinoma, etc.) and its independent prognostic significance in nine cancers (e.g., adrenocortical carcinoma). CDKN2C expression was related to the immune microenvironment, suggesting its potential usefulness as a prognostic marker in immunotherapy. CONCLUSIONS: This study identified upregulated CDKN2C expression and its clinical significance in SCLC and other multiple cancers, suggesting its potential usefulness as a biomarker in treating and differentiating cancers.

Biochar enhances partial denitrification/anammox by sustaining high rates of nitrate to nitrite reduction.

To examine the short-term effects of biochar on the partial-denitrification anammox (PD/A) process, the adsorption kinetics, nitrogen degradation, electron transfer properties, and microbial community succession of wastewater treatment systems with and without biochar added were monitored and characterized. The results showed that biochar increased nitrate reduction rates, which enhanced total nitrogen (TN) removal of the system by about 10%. The findings attributed improved TN removal to biochar's influence in accelerating electron transfer rather than its adsorption properties. Analysis of the nitrogen transfer pathway showed that when sufficient substrate was available, the anammox and denitrification reactions simultaneously removed nitrogen. When the nitrite supply was insufficient, the anammox reaction outcompeted the denitrification reaction for regenerated nitrite. Integrated microbial community and functional protein analyses indicated that biochar addition increased the abundance of Ca. Kuenenia and Pseudomonas. Meanwhile, biochar modulates denitrifying cellular metabolism by inducing protein changes.

Amine- and thiol-bifunctionalized mesoporous silica material for immobilization of Pb and Cd: Characterization, efficiency, and mechanism.

In this study, a two-step functionalizing strategy by combining co-condensation with grafting procedures was employed to synthesize well-ordered Amino- and Thiol-Bifunctionalized SBA-15 (ATBS) mesoporous silica. Its physicochemical properties, performance, and mechanisms in immobilization of toxic metals Pb and Cd in water and soil were investigated. After bi-functionalization, X-ray diffractometer, transmission electron microscope, and N2 adsorption-desorption measurements confirmed that the ATBS maintained a highly-ordered mesoporous structure, large surface area and pore volume. The elemental analysis, Fourier transform infrared spectroscopy and X-ray Photoelectron Spectroscopy (XPS) evidenced the successful incorporation of amine and thiol groups into ATBS. These structure and functional characteristics of ATBS benefited Pb and Cd sorption. Sorption isotherms of Pb and Cd were better fit with Sips and Redlich-Peterson models. Sorption kinetics suggested that Pb sorption was mainly regulated by chemical reactions, whereas both diffusion process and chemical reactions were rate-regulating steps in Cd sorption. ATBS showed the maximum sorption capacities for Pb and Cd at 120 and 38 mg g-1, respectively. The sorption mechanisms revealed by XPS measurements suggested that Cd sorption was mainly attributed to thiol groups while Pb was efficiently bond to both thiol and amino groups. High and stable sorption efficiencies were attained in the pH range of 4-6, with a higher affinity towards Pb than Cd. Furthermore, its ability to immobilize Pb and Cd in soils was examined with an incubation experiment, which showed that ATBS reduced 30-56% of MgCl2-extractable Pb and Cd in a contaminated soil. The synthesized sorbent via the two-step functionalizing strategy shows high sorption efficiency towards Pb and Cd, and thus it has potential application in remediating Pb and Cd contaminated water and soils.

Boosting photo-biochemical conversion and carbon dioxide bio-fixation of Chlorella vulgaris in an optimized photobioreactor with airfoil-shaped deflectors.

Aiming at ameliorating the poor hydrodynamic regimes and uneven light distribution in the conventional airlift flat-plate photobioreactor (AFP-PBR), a novel PBR with static airfoil-shaped deflectors (ASD-PBR) is proposed in this study to boost the microalgal biomass manipulation and hence the photo-biochemical conversion. The ASD module accelerated the circulation of microalgal suspension from the center to two sides with the help of bubbling so that the microalgal cells got more opportunities to access the light source. Compared with the control PBR, the solution velocity along the incident light direction increased by 114.8% in the newly-proposed ASD-PBR. Furthermore, the ASD module also served as a static mixer, which resulted in an increment of 11.5% in mass transfer coefficient and a decrement of 21.4% in mixing time. The amended hydrodynamic characteristics eventually contributed to an improvement of 18.3% and 10.9% in the maximum algal biomass yield and CO2 fixation rate, respectively.

Achieving single-stage partial nitritation and anammox (PN/A) using a submerged dynamic membrane sequencing batch reactor (DM-SBR).

Single-stage partial nitration and anammox (PN/A) process was achieved in a sequencing batch reactor (SBR) using a submerged dynamic membrane (DM) in this study. The reactor was stably operated for 200 days, and the nitrogen removal efficiency (NRE) was sustained at 70.3 ± 7.2% at a nitrogen loading rate (NLR) ranging from 0.1 to 0.3 kgNm-3  day-1 with a hydraulic retention time (HRT) of 24 hr. When the NLR was 0.2 kgN m-3 day-1 , the NRE achieved was high as 80% with a low concentration of dissolved oxygen (DO) of 0.13 mg/L. In addition, the specific activity of anammox bacteria and ammonia-oxidizing bacteria (AOB) reached was 2.72 and 16.80 gN gVSS-1 day-1 , respectively. The DM intercepted the biomass due to the lamellar, intact, dense biofilm self-generated on the surface of the supporting material, which had an effluent turbidity of 10 NTU. The enriched anammox functional bacteria were Candidatus Jettenia (11.06%) and the AOB-like functional bacteria consisted primarily of Nitrosomonas, with a relative abundance of 2.76%, which ensured the PN/A process proceeding. This study provides a novel reactor configuration of the single-stage PN/A process in the view of practical applications. PRACTITIONER POINTS: Single-stage partial nitration and anammox (PN/A) process was achieved using a submerged dynamic membrane (DM) in this study. The reactor was stably operated for 200 days, and the nitrogen removal efficiency was sustained at 70.3 ± 7.2%. The feasibility of the PN/A system with DM is evaluated. The main objective is to provide a control strategy of the DM-SBRs for practical applications.

Stripped Electrode Based Electrowetting-on-Dielectric Digital Microfluidics for Precise and Controllable Parallel Microdrop Generation.

Microdrop generation with excellent controllability and volume precision is of paramount significance for a large variety of microfluidic applications. In this work, we propose a new configuration comprising only stripped electrodes of rectangular shape for the closed electrowetting-on-dielectric digital microfluidic (EWOD DMF) system and investigate its parallel microdrop generation outcomes via a numerical approach. The microfluidic droplet motion is solved by a finite-volume scheme on a fixed computational domain. The numerical model is verified by an experimental study of microdrop production from an EWOD DMF device with three different electrode designs. After model verification, we examine the influences of the equilibrium contact angle and the spacing of the microchannel on stripped electrode based microdrop generation outcomes and discover five different regimes including the phenomena of satellite droplet formation and separation cessation. Despite the various generation outcomes, the daughter droplet size is found to vary linearly with a dimensionless EWOD parameter κ*. More importantly, for all successful generations, the deviation of the daughter droplet size from that of the stripped electrode is smaller than 3.5%, which even reaches zero in proper conditions. This new configuration can be utilized as a convenient alternative for electrowetting-induced parallel microdrop production with excellent precision and controllability.

Photo-bioreactor design for microalgae: A review from the aspect of CO2 transfer and conversion.

Photobioreactor (PBR) is the most critical equipment for microalgal photosynthetic fixation of CO2. It provides suitable environmental conditions, such as CO2, light and nutrients, for microalgal growth. As the major carbon source for microalgae, CO2 gas is pumped into PBR with the formation of bubbles and formed gas-liquid flow. The gas-liquid flow affects CO2 and nutrients transmission as well as microalgae cells distribution in PBR, thereby affecting the biochemical reaction of microalgae. While the migration and transport of biochemical reaction products affect the two-phase flow, phase distribution and flow resistance in the PBR in return, thus affecting the transport of light and nutrients. Therefore, microalgal photosynthetic rate is determined synthetically by two-phase flow and the transport of CO2, light and nutrients in PBR. Deep understanding of gas-liquid two-phase flow, energy and mass transfer coupling with microalgal growth in PBR is the cornerstone for the design of an efficient microalgae PBR.

Microalgal lipids production and nutrients recovery from landfill leachate using membrane photobioreactor.

The aim of this work was to realize high-efficiency nutrients recovery from landfill leachate (LL) for microalgal lipids production. Negative effects of LL on microalgal lipid synthesis was revealed and a scalable membrane-based tubular photobioreactor (SM-PBR) was proposed to offset these negative effects. Microalgal biomass concentration was improved from 0 g/L in the traditional PBR to 2.13 g/L in the SM-PBR. Major operating conditions were optimized to enhance nutrients recovery and lipid productivity. The maximum N recovery efficiency of 74.31% and the maximum daily lipid production of 404.98 mg/d were obtained under the volume ratio of 5:3 (microalgae culture/LL stream) and phosphate feeding concentration of 50 mg/L. The obtained lipid was convinced to have a good combustion and anti-degradation property, with high cetane number (>52%) and low linolenic acid content (<12%). The SM-PBR provided a feasible approach for large-scale microalgal lipid production with LL.

Human epidermal growth factor receptor 2 expressions and Janus-activated kinase/signal transducer and activator of transcription 3-suppressor of cytokine signaling 3 pathway may be associated with clinicopathological features and prognosis of gastric cancer.

OBJECTIVE: Our study aims to investigate the expression of human epidermal growth factor receptor 2 (HER-2), Janus-activated kinase/signal transducer, and activator of transcription 3-suppressor of cytokine signaling 3 (JAK/STAT3-SOCS3) pathway in gastric cancer (GC) and its relationship with clinicopathological features and prognosis of GC. MATERIALS AND METHODS: A total of 105 GC patients who underwent surgical resection were enrolled for our study, and corresponding 60 normal tissues adjacent to carcinoma (>10 cm from the carcinoma tissues) as control groups. Spearman correlation analysis was applied for correlation analysis among HER-2, STAT3, and SOCS3. Kaplan-Meier method and Cox proportional hazard model were applied for investigating the associations among HER-2, STAT3 and SOCS3 expressions and prognosis of GC patients. RESULTS: The expressions of HER-2 and STAT3 in GC tissues were increased, but SOCS3 expression showed an evident decrease with the change of depth of invasion, lymph node metastasis (LNM), and tumor node metastasis staging (all P < 0.05). The result of Spearman correlation analysis showed a positive correlation between HER-2 and STAT3 (r = 0.216, P < 0.05), while a negative correlation was observed between STAT3 and SOCS3 (r = -0.237, P < 0.05). Kaplan-Meier analysis results showed that the survival time of HER-2 and STAT3 negative group were both higher than their positive group (both P < 0.001), nevertheless, the survival time of SOCS3 negative group was lower than positive group (P < 0.001). Cox regression multivariate analysis indicated HER-2, STAT3, SOCS3, LNM, and depth of invasion were independent prognostic factors influenced the prognosis of GC (all P < 0.001). CONCLUSION: Our study revealed that HER-2 may participates in the development, invasion and metastasis of GC by affecting the JAK/STAT3 pathway. HER-2, STAT3, and SOCS3 serve as reference indexes for the prognosis of GC patients.

Phytate promoted arsenic uptake and growth in arsenic-hyperaccumulator Pteris vittata by upregulating phosphorus transporters.

While phosphate (P) inhibits arsenic (As) uptake by plants, phytate increases As uptake by As-hyperaccumulator Pteris vittata. Here we tried to understand the underling mechanisms by investigating the roles of phytate in soil As desorption, P transport in P. vittata, short-term As uptake, and plant growth and As accumulation from soils. Sterile soil was used to exclude microbial degradation on phytate. Results showed that inorganic P released 3.3-fold more As than that of phytate from soil. However, P. vittata accumulated 2-2.5 fold more As from soils with phytate than that in control and P treatment. In addition, different from P suppression on As uptake, solution uptake experiment showed that As uptake in phytate treatment was comparable to that of control under 0.1-7.5 µM As after 1-24 h. Moreover, responding to phytate, P. vittata P transporter PvPht1;3 increased by 3-fold while PvPht1;1 decreased by 65%. The data suggested that phytate upregulated PvPht1;3, thereby contributing to As uptake in P. vittata. Our results showed that, though with lower As release from soil compared to P, phytate induced more As uptake and better growth in P. vittata by upregulating P transporters.