Dual-Ligand Red Perovskite Ink for Electrohydrodynamic Printing Color Conversion Arrays over 2540 dpi in Near-Eye Micro-LED Display.

The lack of stability of red perovskite nanocrystals (PeNCs) remains the main problem that restricts their patterning application. In this work, the dual-ligand passivation strategy was introduced to stabilize PeNCs and inhibit their halogen ion migration during high-voltage electrohydrodynamic (EHD) inkjet printing. The as-printed red arrays exhibit the highest emisson intensity and least blue shift compared with samples with other passivation strategies under a high electric field during EHD inkjet printing. Combining with blue and green PeNC inks, single-color and tricolor color conversion layer arrays were successfully printed, with minimum pixel size of 5 µm and the highest spatial resolution of 2540 dpi. The color coordinate of CsPbBrI2 NCs arrays are located close to the red point, with a color gumat of 97.28% of Rec. 2020 standard. All of these show great potential in the application of color conversion layers in a near-eye micro-LED display.

Compact In Situ Electrochemical NMR with Wireless and Anti-interference Strategy in Multiscenario Applications.

The integration of electrochemistry with nuclear magnetic resonance (NMR) spectroscopy recently offers a powerful approach to understanding oxidative metabolism, detecting reactive intermediates, and predicting biological activities. This combination is particularly effective as electrochemical methods provide excellent mimics of metabolic processes, while NMR spectroscopy offers precise chemical analysis. NMR is already widely utilized in the quality control of pharmaceuticals, foods, and additives and in metabolomic studies. However, the introduction of additional and external connections into the magnet has posed challenges, leading to signal deterioration and limitations in routine measurements. Herein, we report an anti-interference compact in situ electrochemical NMR system (AICISENS). Through a wireless strategy, the compact design allows for the independent and stable operation of electrochemical NMR components with effective interference isolation. Thus, it opens an avenue toward easy integration into in situ platforms, applicable not only to laboratory settings but also to fieldwork. The operability, reliability, and versatility were validated with a series of biomimetic assessments, including measurements of microbial electrochemical systems, functional foods, and simulated drug metabolisms. The robust performance of AICISENS demonstrates its high potential as a powerful analytical tool across diverse applications.

Quantitative determination of microbial materials activity based on infrared extinction properties.

Microbial bacteria play an irreplaceable role in natural and human production and life; thus, determining their activities is an important issue. This study proposed a method to quantitatively determine the activity of microbial materials through extinction property calculation using infrared spectroscopy. Complex refractive indices of different active biomaterials were calculated based on their infrared spectra, and their extinction properties were determined using the discrete dipole approximation method. Using partial least squares (PLS), support vector regression (SVR), and extreme learning machine (ELM) regression, quantitative determination models of microbial materials based on infrared extinction properties were established to predict their activity. The results demonstrated that the model of least angle regression (LAR) combined with PLS exhibited better potential for the determination of biomaterial activity. The coefficient of determination (R2) values acquired by the optimal model for the three biomaterials were 0.9699, 0.9744, and 0.9621, respectively. These findings suggested that a rapid and accurate quantitative determination of microbial activity can be achieved based on extinction property.

Optical power degradation mechanisms in 271†nm AlGaN-based deep ultraviolet light-emitting diodes.

The degradation of AlGaN-based UVC LEDs under constant temperature and constant current stress for up to 500 hrs was analyzed in this work. During each degradation stage, the two-dimensional (2D) thermal distributions, I-V curves, optical powers, combining with focused ion beam and scanning electron microscope (FIB/SEM), were thoroughly tested and analyzed the properties and failure mechanisms of UVC LEDs. The results show that: 1) the opto-electrical characteristics measured before/during stress indicate that the increased leakage current and the generation of stress-induced defects increase the non-radiative recombination in the early stress stage, resulting in a decrease in optical power; 2) the increase of temperature caused by the deterioration of the Cr/Al layer of p-metal after 48 hrs of stress aggravates the optical power in UVC LEDs. The 2D thermal distribution in conjunction with FIB/SEM provide a fast and visual way to precisely locate and analyze the failure mechanisms of UVC LEDs.

Impacts of p-GaN layer thickness on the photoelectric and thermal performance of AlGaN-based deep-UV LEDs.

The effects of different p-GaN layer thickness on the photoelectric and thermal properties of AlGaN-based deep-ultraviolet light-emitting diodes (DUV-LEDs) were investigated. The results revealed that appropriate thinning of the p-GaN layer enhances the photoelectric performance and thermal stability of DUV-LEDs, reducing current crowding effects that affect the external quantum efficiency and chip heat dissipation. The ABC + f(n) model was used to analyse the EQE, which helped in identifying the different physical mechanisms for DUV-LEDs with different p-GaN layer thickness. Moreover, the finite difference time domain simulation results revealed that the light-extraction efficiency of the DUV-LEDs exhibits a trend similar to that of damped vibration as the thickness of the p-GaN layer increases. The AlGaN-based DUV-LED with a p-GaN layer thickness of 20 nm exhibited the best photoelectric characteristics and thermal stability.

Investigation on external quantum efficiency droops and inactivation efficiencies of AlGaN-based ultraviolet-c LEDs at 265-285 nm.

The temperature-dependent external quantum efficiency (EQE) droops of 265 nm, 275 nm, 280 nm, and 285 nm AlGaN-based ultraviolet-c light-emitting diodes (UVC-LEDs) differed in Al contents have been comprehensively investigated. The modifiedABCmodel (R = An+Bn2+Cn3) with the current-leakage related term,f(n)= Dn4, has been employed to analyze the recombination mechanisms in these UVC-LED samples. Experimental results reveal that, at relatively low electrical-current levels, the contribution of Shockley-Read-Hall (SRH) recombination exceeds those of the Auger recombination and carrier leakage. At relatively high electrical-current levels, the Auger recombination and carrier leakage jointly dominate the EQE droop phenomenon. Moreover, the inactivation efficiencies of 222 nm excimer lamp, 254 nm portable Mercury lamp, 265 nm, 280 nm, and 285 nm UVC-LED arrays in the inactivation ofEscherichia colihave been experimentally investigated, which could provide a technical reference for fighting against the new COVID-19.

The concept of "Four Walls, Two Poles" in the lesions of the thalamus and ganglion regions: case report and literature review.

BACKGROUND: There are few articles about the surgical techniques of thalamic glioma and the lesions in the basal ganglia area. According to three existing cases and the literature review (Twelve articles were summarized which mainly described the surgical techniques), we discuss the surgical characteristics of lesions of the thalamus and basal ganglia area and summarize the relevant surgical skills. CASE PRESENTATION: Of the three cases, two were thalamic gliomas and one was brain abscess in basal ganglia. According to the three-dimensional concept of the "Four Walls, Two Poles", lesions of the thalamus and basal ganglia were surgically removed, and the operative effect was analysed by relevant surgical techniques. Surgical resection of the lesions of the thalamus and basal ganglia area according to the three-dimensional concept of the "Four Walls, Two Poles" has achieved good surgical results. Relevant surgical techniques, such as the use of retractors, the use of aspirators, the choice of surgical approaches, and the haemostasis strategy, also played an important role in the operation process. CONCLUSIONS: In the presented three cases the three-dimensional concept of the "Four Walls, Two Poles" allowed for safe surgical resection of lesions of the thalamus and basal ganglia.

A Novel Rotational Field Eddy Current Planar Probe with Two-Circular Sector Pickup Coils.

A new rotational field planar eddy current probe is proposed. The probe is combined with two orthogonal driver traces and a pickup coil that includes two-circular sector windings with series connection. Rotational eddy currents are induced by driver traces of the same amplitude and frequency, but fed with 90° phase different alternating exciting currents. An experimental demonstration using prototypes of the probes and artificial defects showed that the probe with a two-circular sector pickup coil is more sensitive for detecting the short defects than the probe with a circular pickup coil.

Duopoly Price Competition in Wireless Sensor Network-Based Service Provision.

The Internet of Things (IoT) is emerging as a new communication paradigm and has attracted a significant amount of attention from both academic and engineering communities. In this paper, we consider an IoT market where three roles exist: Wireless Sensor Networks (WSNs), two service providers (SPs) and end users. The WSNs are responsible for sensing and providing data to the two SPs. Based on the sensed data from WSNs, the two SPs compete to provide services to the end users. We model the relationship between the two SPs and end users as a two-stage Stackelberg game, where the two SPs set the prices for their services firstly, and then the end users decide which SP to choose. Specifically, we consider two price-competition scenarios of the two SPs, which are engaged in two games, one is a noncooperative strategic game (NSG) where the two SPs set the prices for services simultaneously, the other is a Stackelberg game (SG) where SP1 who sets the price first is the leader and SP2 who sets the price after is the follower. Each user decides whether and which SP to purchase services from based on prices and service rates. An equilibrium is achieved in each of the two scenarios. Numerical results are conducted to verify our theoretical analysis.

Two Novel Information Entropy Indices for Analysis of the Eddy Current Distribution.

The Koch curve exciting coil eddy current sensor is a kind of novel flexible planar eddy current probe. In this study, an intersection angle spectrum entropy index and a radial direction energy spectrum entropy were proposed to evaluate the eddy current distribution. Eddy current distributions induced by one turn of a circular coil and one turn of a second order Koch curve coil feed with different exciting frequency alternative currents and at different lift-off distances, were simulated and the eddy current distributions varying with lift-off distance in different exciting frequencies were compared by the two proposed indices. With the increase of the lift-off distance or the decrease of exciting frequency, the similarity between the shape of the Koch curve and the eddy current distribution became weakened and the degree of the concentration of the eddy current distribution in the specimen under the exciting coil was loosened.

Service-oriented node scheduling scheme for wireless sensor networks using Markov random field model.

Future wireless sensor networks are expected to provide various sensing services and energy efficiency is one of the most important criterions. The node scheduling strategy aims to increase network lifetime by selecting a set of sensor nodes to provide the required sensing services in a periodic manner. In this paper, we are concerned with the service-oriented node scheduling problem to provide multiple sensing services while maximizing the network lifetime. We firstly introduce how to model the data correlation for different services by using Markov Random Field (MRF) model. Secondly, we formulate the service-oriented node scheduling issue into three different problems, namely, the multi-service data denoising problem which aims at minimizing the noise level of sensed data, the representative node selection problem concerning with selecting a number of active nodes while determining the services they provide, and the multi-service node scheduling problem which aims at maximizing the network lifetime. Thirdly, we propose a Multi-service Data Denoising (MDD) algorithm, a novel multi-service Representative node Selection and service Determination (RSD) algorithm, and a novel MRF-based Multi-service Node Scheduling (MMNS) scheme to solve the above three problems respectively. Finally, extensive experiments demonstrate that the proposed scheme efficiently extends the network lifetime.

Electrohydrodynamic Inkjet Printing of Three-Dimensional Perovskite Nanocrystal Arrays for Full-Color Micro-LED Displays.

Perovskite nanocrystal (PeNC) arrays are showing a promising future in the next generation of micro-light-emitting-diode (micro-LED) displays due to the narrow emission linewidth and adjustable peak wavelength. Electrohydrodynamic (EHD) inkjet printing, with merits of high resolution, uniformity, versatility, and cost-effectiveness, is among the competent candidates for constructing PeNC arrays. However, the fabrication of red light-emitting CsPbBrxI(3-x) nanocrystal arrays for micro-LED displays still faces challenges, such as low brightness and poor stability. This work proposes a design for a red PeNC colloidal ink that is specialized for the EHD inkjet printing of three-dimensional PeNC arrays with enhanced luminescence and stability as well as being adaptable to both rigid and flexible substrates. Made of a mixture of PeNCs, polymer polystyrene (PS), and a nonpolar xylene solvent, the PeNC colloidal ink enables precise control of array sizes and shapes, which facilitates on-demand micropillar construction. Additionally, the inclusion of PS significantly increases the brightness and environmental stability. By adopting this ink, the EHD printer successfully fabricated full-color 3D PeNC arrays with a spatial resolution over 2500 ppi. It shows the potential of the EHD inkjet printing strategy for high-resolution and robust PeNC color conversion layers for micro-LED displays.

Brightened Bicomponent Perovskite Nanocomposite Based on Förster Resonance Energy Transfer for Micro-LED Displays.

Lead halide perovskite quantum dots (PQDs) are making their way toward next-generation display applications, such as serving as color conversion layers in micro-light-emitting-diode (micro-LED) arrays. Red PQDs containing iodine exhibit weaker brightness compared with their green counterpart when employed as color conversion layers. Therefore, PQDs with enhanced brightness are highly favorable for micro/mini-LED displays. A universal strategy of bicomponent perovskite nanocomposite (BPNC) with significantly enhanced photoluminescence (PL) intensity is proposed through the built-in Förster resonance energy transfer (FRET) from the core CsPbBr3 to the shell γ-CsPbI3 , and it is confirmed that it is through a pair of combined quasi-degenerate energy levels in the blue spectra region that the FRET is conducted, resulting in a high excitation wavelength selectivity. Owing to the highly efficient energy transition route from blue excitation to red emission established by the FRET, the BPNC exhibits the brightest single-peak red photoluminescence with near 100% quantum yield. The BPNC with FRET is further proven to be adaptable to a wide range of emission wavelengths. The BPNCs in a blue micro-LED array are employed as color downconversion layers, and excellent color conversion properties and high color gamut are demonstrated. This strategy of BPNC paves a road to the full-color micro-LED displays.

Mathematical model and genomics construction of developmental biology patterns using digital image technology.

Biological pattern formation ensures that tissues and organs develop in the correct place and orientation within the body. A great deal has been learned about cell and tissue staining techniques, and today's microscopes can capture digital images. A light microscope is an essential tool in biology and medicine. Analyzing the generated images will involve the creation of unique analytical techniques. Digital images of the material before and after deformation can be compared to assess how much strain and displacement the material responds. Furthermore, this article proposes Development Biology Patterns using Digital Image Technology (DBP-DIT) to cell image data in 2D, 3D, and time sequences. Engineered materials with high stiffness may now be characterized via digital image correlation. The proposed method of analyzing the mechanical characteristics of skin under various situations, such as one direction of stress and temperatures in the hundreds of degrees Celsius, is achievable using digital image correlation. A DBP-DIT approach to biological tissue modeling is based on digital image correlation (DIC) measurements to forecast the displacement field under unknown loading scenarios without presupposing a particular constitutive model form or owning knowledge of the material microstructure. A data-driven approach to modeling biological materials can be more successful than classical constitutive modeling if adequate data coverage and advice from partial physics constraints are available. The proposed procedures include a wide range of biological objectives, experimental designs, and laboratory preferences. The experimental results show that the proposed DBP-DIT achieves a high accuracy ratio of 99,3%, a sensitivity ratio of 98.7%, a specificity ratio of 98.6%, a probability index of 97.8%, a balanced classification ratio of 97.5%, and a low error rate of 38.6%.

Nanogold/graphene as sensing platform coupled with ferrocene/gold as signal amplifier for sandwich-like voltammetric immunosensor of human chorionic gonadotropin.

An effective method to detect human chorionic gonadotropin (hCG) is of significance for early pregnancy testing and clinical diagnosis of non-pregnancy related diseases. Herein, a sensitive sandwich-like electrochemical immunosensor of hCG was constructed by introducing nanogold/graphene (Au/GNS) hybrids and ferrocene/gold nanoparticles (Fc/Au) as the sensing platform and signal amplifier, respectively. In this sensing platform, the Au/GNS hybrid was dedicated to increasing the loading capacity of primary antibody (Ab1) and accelerate the electron transport, and Au is devoted to assembling secondary antibodies (Ab2) and Fc derivative (Fc-SH) to fabricate signal amplifier (Ab2-AuNPs-Fc). By selecting Fc as the signal probe, results revealed that peak currents increased when the special recognition among Ab1, hCG, and Ab2 occurred. A novel and sensitive sandwich-like immunosensor of hCG was thus constructed. After optimizing various testing conditions, a wide linearity from 0.005 to 7.0 ng mL-1 and a low detection limit of 1.0 pg mL-1 were achieved for hCG analysis, suggesting this method is useful for hCG analysis.

Baicalin suppresses the migration and invasion of breast cancer cells via the TGF-ß/lncRNA-MALAT1/miR-200c signaling pathway.

Metastasis is the major cause of death and failure of cancer chemotherapy in patients with breast cancer (BC). Activation of TGF-ß/lncRNA-MALAT1/miR-200c has been reported to play an essential role during the metastasis of BC cells. The present study aimed to validate the suppression of BC-cell migration and invasion by baicalin and explore its regulatory effects on the TGF-ß/lncRNA-MALAT1/miR-200c signaling pathway. We found that baicalin treatment inhibited cell viability and migration and invasion. Mechanistically, baicalin treatment significantly downregulated the expression of TGF-ß, ZEB1, and N-cadherin and upregulated E-cadherin on both mRNA and protein levels. Additionally, baicalin treatment significantly downregulated the expression of lncRNA-MALAT1 and upregulated that of miR-200c. Collectively, baicalin significantly suppresses cell viability, migration, and invasion of BC cells possibly by regulating the TGF-ß/lncRNA-MALAT1/miR-200c pathway.

Design and analysis of self-adapted task scheduling strategies in wireless sensor networks.

In a wireless sensor network (WSN), the usage of resources is usually highly related to the execution of tasks which consume a certain amount of computing and communication bandwidth. Parallel processing among sensors is a promising solution to provide the demanded computation capacity in WSNs. Task allocation and scheduling is a typical problem in the area of high performance computing. Although task allocation and scheduling in wired processor networks has been well studied in the past, their counterparts for WSNs remain largely unexplored. Existing traditional high performance computing solutions cannot be directly implemented in WSNs due to the limitations of WSNs such as limited resource availability and the shared communication medium. In this paper, a self-adapted task scheduling strategy for WSNs is presented. First, a multi-agent-based architecture for WSNs is proposed and a mathematical model of dynamic alliance is constructed for the task allocation problem. Then an effective discrete particle swarm optimization (PSO) algorithm for the dynamic alliance (DPSO-DA) with a well-designed particle position code and fitness function is proposed. A mutation operator which can effectively improve the algorithm's ability of global search and population diversity is also introduced in this algorithm. Finally, the simulation results show that the proposed solution can achieve significant better performance than other algorithms.

Highly sensitive electrochemical determination of methotrexate based on a N-doped hollow nanocarbon sphere modified electrode.

As an antineoplastic drug, methotrexate (MTX) is widely applied in cancer therapies; however it has potentially toxic activity, and thus the qualitative and quantitative determination of MTX is of great significance. In this paper, by using dopamine synchronously as a carbon and N source, N-doped hollow nanocarbon sphere (NHNC) hybrids were prepared via a simple self-polymerization method and used to construct a new electrochemical sensor for MTX. The prepared NHNC exhibits a uniform hollow nanostructure with high conductivity and electrocatalytic properties as well as large adsorption capacity and surface area, which are the key factors for improving the sensor sensitivity of MTX. For achieving highly sensitive determination of MTX, various conditions were optimized, and the final results show that the NHNC modified electrode has excellent sensing responses for MTX, and it has a wide linear range from 0.05 to 14.0 µM coupled with a low detection limit of 0.01 µM. Finally, studies on the reproducibility, stability and selectivity of the NHNC modified electrode show that the corresponding results are satisfactory.

Efficacy of UVC-LED in water disinfection on Bacillus species with consideration of antibiotic resistance issue.

Ultraviolet light emitting diode (UV-LED) has attracted extensive attention as a new technology to replace traditional mercury lamp for water disinfection. This study reported for the first time the application of UVC-LEDs in range of 200-280 nm for the treatment of two Gram-positive tetracycline resistant bacteria (TRB) from Bacillus species and their tetracycline resistant gene (TRG). The results showed that UVC-LEDs can inactivate TRB up to 5.7-log and inhibit TRG expression, especially at 268 nm. The required fluence was approximate to that of the referential non-resistant bacteria using the same UVC-LED, but far less than that of TRB using mercury lamp. After UVC-LED irradiation, photoreactivation was the dominant mechanism to repair TRB, just like non-resistant bacteria. But contrary to non-resistant bacteria, the regrowth ratio of TRB was remarkably high at 24 h since the end of the irradition, nevertheless the number of the regrown bacteria in the irradiated water was still less than that in the non-irradiated water. Whereas TRB restored resistance after repair even applying 268 nm at a fluence up to 46.08 mJ/cm2 (maximum in this study). This study highlights the merits of UVC-LED to effectively inactivate TRB in a prompt, energy-efficient and resistance-reducing way, while future study on TRB regrowth and resistance resilience is needed.

Comparison of the performance of pulsed and continuous UVC-LED irradiation in the inactivation of bacteria.

Ultraviolet light-emitting diode (UV-LED) is a newly emerging UV light source with a potential to replace the conventional chemical methods, mercury UV lamps and xenon lamps in water disinfection. UV-LEDs are characterized by the diversity in wavelengths and can be turned on and off with a high and adjustable frequency, making them an attractive candidate for pulsed light (PL) disinfection apart from the conventional continuous wave (CW) operation. Previous studies on comparison between the PL and CW UV-LED irradiations for the inactivation of bacterium in water disinfection are limited and results conflict. In this work, PL and CW UV-LED in the C-spectral band (UVC-LED) irradiations were compared at equivalent fluence in the inactivation and subsequent photoreactivation of E. coli bacteria. In addition, effect of different driving currents and ambient temperatures on solder temperature of the PL and CW UVC-LED irradiation was also examined. Under the equivalent fluences, the PL and CW UVC-LED irradiations brought comparable inactivation efficiency and similar photoreactivation of the E. coli. Moreover, the PL UVC-LED exhibited a much lower solder temperature than the CW UVC-LED irradiation. On the other hand, CW UVC-LED irradiation, higher ambient temperature and higher driving current increased the solder temperature that resulted to a negative impact on the wavelength, full width at half maximum, optical power and irradiance, which are key factors in the UVC-LED disinfection efficiency. In all, this work reports the comparison between PL and CW in UVC-LED irradiation for inactivating E. coli bacteria and firstly revealed the photoreactivation of the E. coli after the PL UVC-LEDs irradiation.