In this article, we propose a facile method for synthesis of K 2 SiF 6 :Mn 4+ phosphor and discuss its promising application in warm-white light emitting diodes (LED

Critically ill patients with coronavirus diseases 2019 (COVID-19) are of grave concern. Those patients usually underwent a stage of excessive inflammation before developing acute respiratory distress syndrome. In this study, we test the hypothesis that short-term, low-to-moderate-dose corticosteroids would benefit patients when used in the early phase of excessive inflammation, namely, the therapeutic window. Among a Shanghai cohort and a validation cohort, we enrolled COVID-19 patients showing marked radiographic progression. Short-term, low-to-moderate-dose corticosteroids were considered for them. After identifying the possible markers for the therapeutic window, we then divided the patients, based on whether they were treated with corticosteroids within the therapeutic window, into the early-start group and control group. We identified that the therapeutic window for corticosteroids was characterized by a marked radiographic progression and lactase dehydrogenase (LDH) less than two times the upper limit of normal (ULN). The Shanghai cohort comprised of 68 patients, including 47 in the early-start group and 21 in the control group. The proportion of patients requiring invasive mechanical ventilation was significantly lower in the early-start group than in the control group (10.6% vs. 33.3%, difference, 22.7%, 95% confidence interval 2.6-44.8%). Among the validation cohort of 51 patients, similar difference of the primary outcome was observed (45.0% vs. 74.2%, P = 0.035). Among COVID-19 patients with marked radiologic progression, short-term, low-to-moderate-dose corticosteroids benefits patients with LDH levels of less than two times the ULN, who may be in the early phase of excessive inflammation.

In order to meet the requirement of high sensitivity and signal-to-noise ratios (SNR), this study develops and optimizes a piezoresistive pressure sensor by using double silicon nanowire (SiNW) as the piezoresistive sensing element. First of all, ANSYS finite element method and voltage noise models are adopted to optimize the sensor size and the sensor output (such as sensitivity, voltage noise and SNR). As a result, the sensor of the released double SiNW has 1.2 times more sensitivity than that of single SiNW sensor, which is consistent with the experimental result. Our result also displays that both the sensitivity and SNR are closely related to the geometry parameters of SiNW and its doping concentration. To achieve high performance, a p-type implantation of 5 × 1018 cm−3 and geometry of 10 µm long SiNW piezoresistor of 1400 nm × 100 nm cross area and 6 µm thick diaphragm of 200 µm × 200 µm are required. Then, the proposed SiNW pressure sensor is fabricated by using the standard complementary metal-oxide-semiconductor (CMOS) lithography process as well as wet-etch release process. This SiNW pressure sensor produces a change in the voltage output when the external pressure is applied. The involved experimental results show that the pressure sensor has a high sensitivity of 495 mV/V·MPa in the range of 0–100 kPa. Nevertheless, the performance of the pressure sensor is influenced by the temperature drift. Finally, for the sake of obtaining accurate and complete information over wide temperature and pressure ranges, the data fusion technique is proposed based on the back-propagation (BP) neural network, which is improved by the particle swarm optimization (PSO) algorithm. The particle swarm optimization–back-propagation (PSO–BP) model is implemented in hardware using a 32-bit STMicroelectronics (STM32) microcontroller. The results of calibration and test experiments clearly prove that the PSO–BP neural network can be effectively applied to minimize sensor errors derived from temperature drift.

This work investigates the effect of chloride ion (Cl) on dissolution, reactive oxygen species (ROS) generation, and toxicity of citrate-coated silver nanoparticles (AgNPs) under UV irradiation. The dissolution rate was decreased by 0.01 M Cl due to AgCl passivation on the AgNP surface. By contrast, high concentrations of Cl (0.1 or 0.5 M) promoted dissolution due to the formation of soluble Ag-Cl complexes (AgCl ). The generation of O in the AgNPs/Cl/UV system was promoted by 0.01 M Cl, whereas it was retarded by 0.1 or 0.5 M Cl, which was probably because the aggregation of AgNPs at high ionic strength reduced the nanoparticles' surface areas for radical formation. Additionally, Cl contributed to •OH generation in the AgNPs/Cl/UV system, in which the produced •OH concentrations increased with increasing Cl concentrations. The reduction reaction between silver ions and O resulted in lower dissolution rates of AgNPs/Cl mixtures under UV irradiation than those in the dark. The phototoxicity of AgNPs toward E. coli with different concentrations of Cl followed the order of 0.5 M > 0 M > 0.1 M > 0.01 M. Both ROS and dissolved Ag played significant role in the phototoxicity of AgNPs. This work demonstrates the potential importance of anions in the fate and biological impact of AgNPs.

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Rates of sexually transmitted diseases (STDs) in China have soared over the past decade. 1,2 Effective management of STDs is one of the cornerstones of HIV control and provides a unique opportunity for targeted education about HIV prevention. 3,4 A recent study in Thailand revealed that 60% of patients suffering from an STD did not seek treatment from an STD clinic. 5 To reach STD patients, it is important to determine the venues where people seek services and to evaluate the quality of treatment and prevention services in those facilities. The objectives of this study were to identify the facilities in Beijing where most people seek STD treatment and evaluate their prevention services. The study was conducted in Chao Yang District, Beijing, where only large and moderatesized hospitals are authorized to provide STD treatment. Chao Yang District is 30% urban and 70% suburban/rural. There are 1.49 million residents, of whom 12.6% are farmers and 874,000 are migrants. The majority of the population and the large hospitals and other resources are concentrated in the smaller central and northwestern parts of Chao Yang. A cross-sectional study was conducted from November to December 2002 among a sample of each type of STD treating facility. A stratified random sampling method was used to select the sample from the total of 48 comprehensive hospitals. Random samples of 2 of the 3 large hospitals, 5 of the 9 moderate-sized hospitals, and 10 of the 36 small hospitals were selected. In the large and moderate-sized hospitals, the departments providing STD services included dermatovenereology, gynecology, and urology; in the small hospitals, the departments included surgery and gynecology. Information was reviewed and records abstracted from logbooks. The numbers of people diagnosed with urethritis, epididymitis, cervicitis, or pelvic inflammatory disease were recorded. All patients from the STD Center were included.

While an increasing number of organizations have introduced artificial intelligence as an important facilitating tool for learning online, the application of artificial intelligence in e-learning has become a hot topic for research in recent years. Over the past few decades, the importance of online learning has also been a concern in many fields, such as technological education, STEAM, AR/VR apps, online learning, amongst others. To effectively explore research trends in this area, the current state of online learning should be understood. Systematic bibliometric analysis can address this problem by providing information on publishing trends and their relevance in various topics. In this study, the literary application of artificial intelligence combined with online learning from 2010 to 2021 was analyzed. In total, 64 articles were collected to analyze the most productive countries, universities, authors, journals and publications in the field of artificial intelligence combined with online learning using VOSviewer through WOS data collection. In addition, the mapping of co-citation and co-occurrence was explored by analyzing a knowledge map. The main objective of this study is to provide an overview of the trends and pathways in artificial intelligence and online learning to help researchers understand global trends and future research directions.