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In CRISPR/Cas9 genome editing, the tight and persistent target binding of Cas9 provides an opportunity for efficient genetic and epigenetic modification on genome. In particular, technologies based on catalytically dead Cas9 (dCas9) have been developed to enable genomic regulation and live imaging in a site-specific manner. While post-cleavage target residence of CRISPR/Cas9 could alter the pathway choice in repair of Cas9-induced DNA double strand breaks (DSBs), it is possible that dCas9 residing adjacent to a break may also determine the repair pathway for this DSB, providing an opportunity to control genome editing. Here, we found that loading dCas9 onto a DSB-adjacent site stimulated homology-directed repair (HDR) of this DSB by locally blocking recruitment of classical non-homologous end-joining (c-NHEJ) factors and suppressing c-NHEJ in mammalian cells. We further repurposed dCas9 proximal binding to increase HDR-mediated CRISPR genome editing by up to 4-fold while avoiding exacerbation of off-target effects. This dCas9-based local inhibitor provided a novel strategy of c-NHEJ inhibition in CRISPR genome editing in place of small molecule c-NHEJ inhibitors, which are often used to increase HDR-mediated genome editing but undesirably exacerbate off-target effects.

With the continuous improvement of computation and communication capabilities, the Internet of Things (IoT) plays a vital role in many intelligent applications. Therefore, IoT devices generate a large amount of data every day, which lays a solid foundation for the success of machine learning. However, the strong privacy requirements of the IoT data make its machine learning very difficult. To protect data privacy, many privacy-preserving machine learning schemes have been proposed. At present, most schemes only aim at specific models and lack general solutions, which is not an ideal solution in engineering practice. In order to meet this challenge, we propose an efficient and privacy-preserving machine learning training framework (ePMLF) in a fog computing environment. The ePMLF framework can let the software service provider (SSP) perform privacy-preserving model training with the data on the fog nodes. The security of the data on the fog nodes can be protected and the model parameters can only be obtained by SSP. The proposed secure data normalization method in the framework further improves the accuracy of the training model. Experimental analysis shows that our framework significantly reduces the computation and communication overhead compared with the existing scheme.

A photocatalytic three component cascade reaction of quinoxalinones, alkenes, and sulfinic acids toward sulfonated quinoxalin-2(1H)-ones under metal-, strong oxidant-, and external photosensitizer-free conditions was developed.

Background: Asthma is a hackneyed chronic inflammatory disease of the airway. Chryseriol (CSR) is a kind of flavonoid, and has the effect of bronchiectasis, indicating its potential application for treating respiratory diseases. However, the functions of CSR in asthma have not been reported till now. Materials and methods: The histopathologic changes of the lung tissues were assessed by hematoxylin and eosin staining. The cell apoptosis was identified through terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling assay. Total numbers of eosinophils, neutrophils, and macrophages were assessed under microscope. The levels of interleukin (IL)-1β, IL-4, IL-5, and IL-13 were detected by enzyme-linked-immunosorbent serologic assay. The airway hyper-responsiveness (AHR) was evaluated by the whole body plethysmography. The levels of methane dicarboxylic aldehyde, superoxide dismutase, glutathione S-transferase, and glutathione in lung homogenates were confirmed by using corresponding commercial kits. The protein expressions were examined by Western blot analysis. Results: The ovalbumin (OVA) was utilized to establish asthma mouse model. At first, it was revealed that CSR treatment reduced lung injury in OVA-stimulated mice. Moreover, cell apoptosis was enhanced after OVA stimulation but was attenuated by CSR treatment. In addition, CSR treatment decreased the infiltration of inflammatory cells and the production of inflammatory factors in OVA-treated mice. Further investigations demonstrated that CSR treatment relieved AHR in OVA-stimulated mice. The oxidative stress was strengthened in OVA-treated mice, but these effects were relieved by CSR treatment. Lastly, it was discovered that CSR treatment retarded nuclear factor kappa B (NF-κB)/hypoxia-inducible factor 1 alpha (HIF-1α) and p38 mitogen-activated protein kinase (MAPK)/signal transducer and activator of transcription 1 (STAT1) pathways in OVA-triggered asthma mice. Conclusion: Our findings proved that CSR attenuated the progression of OVA-induced asthma in mice through inhibiting NF-κB/HIF-1α and MAPK/STAT1 pathways. This work might highlight the functions of CSR in the treatment of asthma.

Objective To analyse the specific exercise effects of pelvic floor muscle training (PFMT) with or without biofeedback or electrical stimulation on urinary incontinence rehabilitation after radical prostatectomy. Data sources We searched PubMed, Embase, Cochrane Database of Systematic Reviews, Web of Science and Scopus databases for systematic reviews and meta-analyses on PFMT for urinary incontinence after radical prostatectomy from inception to 3 October 2022. Review methods Two authors independently extracted key data from the included studies. The methodological quality of the included studies was assessed using the A Measure Tool to Assess Systematic Reviews-2 checklist. Grading of Recommendations Assessment Development and Evaluation was used to evaluate the quality of the outcomes. Results A total of 18 studies with 29,925 patients were included, all of which were of critically low methodological quality. Biofeedback therapy seemed to show additional benefits compared to PFMT alone; however, the adjunctive role of electrical stimulation remained more controversial due to the lack of strong evidence. Preoperative PFMT sometimes, but not always, showed the potential to improve urinary incontinence. PFMT with the guidance of a therapist could bring some benefits to the patient and was more acceptable to the patient, but consumed some medical resources. Conclusions PFMT has a good effect on improving post-radical prostatectomy incontinence in men, and biofeedback can have an additional beneficial effect on patients, especially in the short-term and medium-term. However, there is insufficient evidence to suggest that electrical stimulation is beneficial for patients with urinary incontinence.

With the rapid development of cloud computing and machine learning, using outsourced stored data and machine learning model for training and online-aided disease diagnosis has a great application prospect. However, training and diagnosis in an outsourced environment will cause serious challenges to the privacy of data. At present, many scholars have proposed privacy preserving machine learning schemes and made a lot of progress, but there are still great challenges in security and low client load. In this paper, we propose a complete privacy preserving outsourced multiclass SVM training and aided disease diagnosis scheme. We design some efficient basic operation algorithms for encrypted data. Then, we design an efficient and privacy preserving SVM model training protocol using the basic operation algorithms. We propose a secure maximum finding algorithm and secure comparison algorithm. Then, we design an efficient online-aided disease diagnosis scheme based on the BFV cryptosystem and blinding technique. Detailed security analysis proves that our scheme can protect the privacy of each participant. The experimental results illustrate that our proposed scheme significantly reduces the computation overhead compared with the previous similar works. Our proposed scheme completes most of the operations of aided disease diagnosis by the cloud servers and the client only needs to complete a small amount of encryption and decryption operations. The overall computation overhead is 0.175 s, and the efficiency of online aided disease diagnosis is improved by 85.4%. At the same time, our proposed scheme provides multiclass diagnosis results, which can better assist doctors in their treatment.

Due to the high recurrence, the HCC prognosis remains poor. Yet, the biomarkers for predicting the recurrence of high-risk patients are currently lacking. We aimed to develop a signature to predict the recurrence of HCC based on NKG2D ligands.The multivariate Cox proportional hazards regression was used to select recurrence-related variables of NKG2D ligands in HCC patients from The Cancer Genome Atlas (TCGA). HCC patients from the OEP000321 dataset and Guilin cohort were used to validate the predictive signature. The mRNA expression of NKG2D ligands was measured by QRT-PCR. Immunohistochemistry analysis of HCC tissue microarray samples was used to identify the expression of NKG2D ligands.In this study, NKG2D ligands expression in the mRNA and protein level was both abnormally expressed in HCC and associated with recurrence-free survival (RFS). Then, the recurrence-related variables of NKG2D ligands in HCC were selected by the multivariate Cox proportional hazards regression. Among the eight NKG2D ligands, MICA (HR = 1.347; 95% CI = 1.012-1.793; p = 0.041), ULBP3 (HR = 0.453; 95% CI = 0.231-0.889; p = 0.021) and ULBP5 (HR = 3.617; 95% CI = 1.819-7.194; p 0.001) were significantly correlated with RFS in the TCGA-LIHC cohort. Then, the signature was constructed by the three NKG2D ligands. The predictive effectiveness of this signature was also validated in the OEP000321 dataset and Guilin cohort. Further, HCC patients were classified into low-risk and high-risk subgroups by the predictive score. Compared with the low-risk group, the high-risk group had poor RFS in both training and validation cohorts. Importantly, compared with the low-risk patients with the G1-G2 stage, the levels of infiltrated NK-activated cells and NKG2D expression were both lower in the high-risk patients.The signature based on MICA, ULBP3, and ULBP5 could predict HCC recurrence.

To evaluate the effect of hysteroscopy and suture on uterine scar diverticulum (CSD) after caesarean section and its influence on blood loss, operation time and antibiotic time. Eighty-nine patients with CSD were divided into observation group (

PurposeThe purpose of the study is to address the problems of low accuracy and missed detection of occluded pedestrians and small target pedestrians when using the YOLOX general object detection algorithm for pedestrian detection. This study proposes a multi-level fine-grained YOLOX pedestrian detection algorithm.Design/methodology/approachFirst, to address the problem of the original YOLOX algorithm in obtaining a single perceptual field for the feature map before feature fusion, this study improves the PAFPN structure by adding the ResCoT module to increase the diversity of the perceptual field of the feature map and divides the pedestrian multi-scale features into finer granularity. Second, for the CSPLayer of the PAFPN, a weight gain-based normalization-based attention module (NAM) is proposed to make the model pay more attention to the context information when extracting pedestrian features and highlight the salient features of pedestrians. Finally, the authors experimentally determined the optimal values for the confidence loss function.FindingsThe experimental results show that, compared with the original YOLOX algorithm, the AP of the improved algorithm increased by 2.90%, the Recall increased by 3.57%, and F1 increased by 2% on the pedestrian dataset.Research limitations/implicationsThe multi-level fine-grained YOLOX pedestrian detection algorithm can effectively improve the detection of occluded pedestrians and small target pedestrians.Originality/valueThe authors introduce a multi-level fine-grained ResCoT module and a weight gain-based NAM attention module.

Purpose The purpose of this paper is to develop high-performance Au-coated Ag alloy wires (ACAA wires) and demonstrate the effect of Au coating layers on the bonding performance and oxidation resistance for stable and reliable electronic packaging applications. Design/methodology/approach ACAA wire with a diameter of approximately 25 µm and Au layer thickness of approximately 100 nm were prepared by the continuous casting, plating and wire drawing method. The bonding performance of the ACAA wires were studied through bonding on 3,535 chips. The oxidation resistance of ACAA wires and Ag alloy wires (AA wires) were comparatively studied by means of chemical oxidation tests, accelerated life tests and electrochemical tests systematically. Findings ACAA wires could form axi-symmetrical spherical free air balls with controllable diameter of 1.5∼2.5 times of the wire diameter after electric flame-off process. The ball shear strength of ACAA wire was higher than that of AA wires. Most importantly, because of the surface Au coating layer, the oxidation resistance of ACAA wires was much enhanced. Research limitations/implications ACAA wires with different lengths of heat affected zone were not developed in this study, which limited their application with different loop height requirements. Practical implications With higher bonding strength and oxidation resistance, ACAA wires would be a better choice than previous reported AA wire in chip packaging which require high stability and reliability. Originality/value This paper provides a kind of novel ACAA wire, which possess the merits of high bonding strength and reliability, and show great potential in electronic packaging applications.

Hypoxia, that is, an inadequate oxygen supply, is linked to neurodegeneration and patients with cardiovascular disease are prone to Alzheimer's disease (AD). 2-Oxoglutarate and ferrous iron-dependent oxygenases (2OGDD) play a key role in the regulation of oxygen homeostasis by acting as hypoxia sensors. 2OGDD also have roles in collagen biosynthesis, lipid metabolism, nucleic acid repair, and the regulation of transcription and translation. Many biological processes in which the60 human 2OGDD are involved are altered in AD patient brains, raising the question as to whether 2OGDD are involved in the transition from normal aging to AD. Here we give an overview of human 2OGDD and critically discuss their potential roles in AD, highlighting possible relationships with synapse dysfunction/loss. 2OGDD may regulate neuronal/glial differentiation through enzyme activity-dependent mechanisms and modulation of their activity has potential to protect against synapse loss. Work linking 2OGDD and AD is at an early stage, especially from a therapeutic perspective; we suggest integrated pathology and in vitro discovery research to explore their roles in AD is merited. We hope to help enable long-term research on the roles of 2OGDD and, more generally, oxygen/hypoxia in AD. We also suggest shorter term empirically guided clinical studies concerning the exploration of 2OGDD/oxygen modulators to help maintain synaptic viability are of interest for AD treatment.

A visible-light-promoted hydroxylation of quinoxalin-2(1H)-ones using recyclable graphitic carbon nitride (g-C3N4) as a heterogeneous photocatalyst has been developed. This protocol enables the selective synthesis of various hydroxyl-containing quinoxalin-2(1H)-ones in good to excellent yields under an ambient air atmosphere. Importantly, this heterogeneous catalyst can be used at least six times without significant loss of activity.

Background. Although probiotics have been shown to improve constipation-related symptoms, a clear consensus on the use of probiotics as a constipation-relieving agent has not been reached, which is attributed to the limited available evidence and inconsistent protocols used in existing studies. Method. A randomized, double-blind, placebo-controlled clinical trial is designed to study the efficiency and possible mechanism of action of probiotics for chronic constipation, in which 200 eligible volunteers with chronic constipation will be randomly assigned to a probiotic group (oral Lactobacillus plantarum P9 probiotic powder, 100 billion colony-forming units (CFUs)/day) or a placebo group. Volunteers, treatment distributors, data collectors, and data analysts will be blinded. The primary outcome is the weekly mean frequency of complete spontaneous bowel movements (CSBMs), and secondary outcomes include weekly mean frequency of CSBMs ≥3, weekly mean frequency of spontaneous bowel movements (SBMs), weekly mean stool appearance score, weekly mean difficulty of passing stool score, weekly percentage of volunteers who use auxiliary measures to assist with defecation (WPUAMA), quality-of-life (QOL) score, emotional status score, gut microbiome, and faecal metabolome. Each outcome measure will be assessed at the time points of preadministration (day 0), administration (day 14 and/or 28), and postadministration (day 42) to identify inter- and intragroup differences. Adverse events will be recorded to evaluate the safety of L. plantarum P9. Discussion. The protocol will provide methodological guidance for other similar studies, avoiding methodological bias and ultimately facilitating the formulation of consensus on the use of probiotics as a constipation-relieving agent. In addition, the results are more comprehensive than those of existing studies and may objectively and scientifically reflect the effectiveness of L. plantarum P9 on constipation. If the expected study findings are obtained, L. plantarum P9, taken as a probiotic, may become a complementary choice for chronically constipated patients. This trial is registered with Chinese Clinical Trial Registry (ChiCTR) (no. ChiCTR2000038396) registered on November 22, 2020, https://www.chictr.org.cn/showproj.aspx?proj=54024.

In this work, nitrogen and fluorine co-doped porous carbon nanosheets (NFPCNS) were fabricated from pharmaceutical drug residues derived from the fermentation synthesis of lincomycin hydrochloride via high-temperature pyrolysis and subsequent KOH activation without adding any nitrogen and fluorine reagents. The obtained NFPCNS exhibits an optimized integration of three dimensional interconnected nanosheet structure, large specific surface area of 2912 m

AimTo investigate the potential association between polymorphisms in genes involved in endothelial function, inflammation and carotid atherosclerosis.MethodsThis was a three-center, population-based sectional survey conducted in Sichuan province of southwestern China. We randomly selected 8 different communities in Sichuan, and the residents in each community volunteered to participate in the survey by face-to-face questionnaire. A total of 2,377 residents with high stroke risk population in the 8 communities were included. Carotid atherosclerosis was evaluated by carotid ultrasound, and the 19 single nucleotide polymorphisms (SNPs) in 10 endothelial function as well as inflammation relevant genes were measured in the high stroke risk population. Carotid atherosclerosis was defined by the presence of carotid plaque or any carotid stenosis ≥15% or mean intima-media thickness (IMT) > 0.9 mm. Generalized multifactor dimensionality reduction (GMDR) approach was used to analyze gene–gene interactions among the 19 SNPs.ResultsAmong the 2,377 subjects with high stroke risk, 1,028 subjects had carotid atherosclerosis (43.2%), of which 852 (35.8%) cases had carotid plaque, 295 (12.4%) cases had ≥15% carotid stenosis, whereas 445 (18.7%) had mean IMT > 0.9 mm. Multivariate logistic regression revealed that IL1A rs1609682 TT and HABP2 rs7923349 TT served as independent risk factors for carotid atherosclerosis (OR, 1.45, 95% CI: 1.034–2.032, p = 0.031, and OR, 1.829, 95% CI: 1.228–2.723, p = 0.003). GMDR analysis indicated that there was a significant gene–gene interaction found among IL1A rs1609682, ITGA2 rs1991013, and HABP2 rs7923349. After adjusting the covariates, the high-risk interactive genotypes in the 3 variants were significantly associated with a significantly higher risk for carotid atherosclerosis (OR, 2.08, 95% CI: 1.257–5.98, p ConclusionThe prevalence of carotid atherosclerosis was observed to be extremely high in the high-risk stroke population in southwestern China. There were associations observed between the specific variants in inflammation and endothelial function relevant genes and carotid atherosclerosis. The high-risk interactive genotypes among IL1A rs1609682, ITGA2 rs1991013, and HABP2 rs7923349 significantly increased the risk of carotid atherosclerosis. These results are expected to provide novel strategies for the prevention of carotid atherosclerosis. The gene–gene interactive analysis used in this study may be very helpful to elucidate complex genetic risk factors for carotid atherosclerosis.

Molybdenum disulfide (MoS2) has been deemed as one of the promising noble-metal-free electrocatalysts for hydrogen evolution reaction (HER), but it suffers from the inert basal plane and low electronic conductivity. Regulating the morphology of MoS2 during the synthesis on conductive substrates is a synergistic strategy for enhancing the HER performance. In this work, vertical MoS2 nanosheets were fabricated on carbon cloth using an atmospheric pressure chemical vapor deposition method. The growth process could be effectively tuned through introducing hydrogen gas during vapor deposition process, resulting in nanosheets with increased edge density. The mechanism for edge-enriching through controlling the growth atmosphere is systematically studied. The as-prepared MoS2 exhibits excellent HER activity due to the combination of optimized microstructures and coupling with carbon cloth. Our findings provide new insights to design advanced MoS2-based electrocatalysts for HER.

Exploring the potential lead compounds for Alzheimer’s disease (AD) remains one of the challenging tasks. Here, we report that the plant extract conophylline (CNP) impeded amyloidogenesis by preferentially inhibiting BACE1 translation via the 5′ untranslated region (5′UTR) and rescued cognitive decline in an animal model of APP/PS1 mice. ADP-ribosylation factor–like protein 6–interacting protein 1 (ARL6IP1) was then found to mediate the effect of CNP on BACE1 translation, amyloidogenesis, glial activation, and cognitive function. Through analysis of the 5′UTR-targetd RNA-binding proteins by RNA pulldown combined with LC-MS/MS, we found that FMR1 autosomal homolog 1 (FXR1) interacted with ARL6IP1 and mediated CNP-induced reduction of BACE1 by regulating the 5′UTR activity. Without altering the protein levels of ARL6IP1 and FXR1, CNP treatment promoted ARL6IP1 interaction with FXR1 and inhibited FXR1 binding to the 5′UTR both in vitro and in vivo. Collectively, CNP exhibited a therapeutic potential for AD via ARL6IP1. Through pharmacological manipulation, we uncovered a dynamic interaction between FXR1 and the 5′UTR in translational control of BACE1, adding to the understanding of the pathophysiology of AD.

Phase-locking between local field potential and spikes has been widely investigated through neurophysiological analysis. Two indices most frequently adopted traditionally include the mean resultant length and p of the Rayleigh test. However, the traditional method is found less reliable for cases with substantial sample sizes or with bimodal distribution. In this article, K we propose an entropy-based method to detect and measure phase-locking. Simulation results prove that the method can be effectively applied to cases with a relatively large sample size and it can effectively detect phase-locking even under bimodal conditions with two peaks of opposite phases. Furthermore, we propose thresholds to help measure the intensity of spike field phase-locking. We also apply the proposed method to our experimental data and find phase locking with two opposite phases, which would be left out in traditional phase-locking analysis.

Bone metastasis is the main cause of death in patients with prostate cancer (PCa), but there lacks effective treatment method. Immunotherapy shows new hopes for bone metastatic PCa patients, while the efficacy is still unsatisfactory and limited by the unique immunosuppressive microenvironment in metastatic bone site. Here, we developed a bone-targeted nano delivery system as a nano-regulator to enhance the immunotherapy of bone metastatic PCa. The nanosystem was assembled via coordination between phytic acid (PA) and Fe3+ to form nano-sized metal-organic-framework (MOF), through which mitoxantrone (MTO) was encapsulated. At cellular level, the nanosystem showed selective cytotoxicity towards RM-1 PCa cells over immune cells, and could induce tumor cells immunogenic cell death (ICD) to improve the immunogenicity of the tumor. Moreover, the nanosystem was able to induce ubiquitination of TGFβ receptor (TβR) on immune cells to promote its degradation, thus serving as a nano-regulator to block the functions of TGF-β, an abundant cytokine that has a systematically immunosuppressive effect in the tumor microenvironment. Upon intravenous injection, the nanoparticle showed pro-longed blood circulation and targeting accumulation into bone metastatic site, and imposed robust anti-tumor effect in combination with αCTLA-4. In addition, bone destruction was significantly alleviated after treatment to reduce the skeletal-related events. Overall, this work provides a biocompatible nanomedicine to restore immune sensitivity of bone metastatic tumor for enhanced immunotherapy by blocking TGF-β signaling pathway.

A highly sensitive and accurate dual-signal strategy is developed for trace Cu2+ detection based on the inner filter effect (IFE) between Tween 20-gold nanoparticles (AuNPs) and CdSe/ZnS quantum dots (QDs). Tween 20-AuNPs are utilized as colorimetric probes and excellent fluorescent absorbers. The fluorescence of CdSe/ZnS QDs can be quenched efficiently by Tween 20-AuNPs via IFE. In the presence of D-penicillamine, D-penicillamine induces the aggregation of Tween 20-AuNPs and the fluorescent recovery of CdSe/ZnS QDs at high ionic strength. Upon addition of Cu2+, D-penicillamine tends to selectively chelate with Cu2+ and then forms the mixed-valence complexes, which consequently inhibits the aggregation of Tween 20-AuNPs and the fluorescent recovery. The dual-signal method is used to quantitatively detect trace Cu2+, with low detection limits of 0.57 μg/L and 0.36 μg/L for colorimetry and fluorescence, respectively. In addition, the proposed method using a portable spectrometer is applied to the detection of Cu2+ in water. This sensitive, accurate and miniature sensing system has potential in environmental evaluations.

Periodicity analysis of sequences generated by a deterministic system is a long-standing challenge in both theoretical research and engineering applications. To overcome the inevitable degradation of the logistic map on a finite-precision circuit, its numerical domain is commonly converted from a real number field to a ring or a finite field. This paper studies the period of sequences generated by iterating the logistic map over ring [Formula: see text] from the perspective of its associated functional network, where every number in the ring is considered as a node, and the existing mapping relation between any two nodes is regarded as a directed edge. The complete explicit form of the period of the sequences starting from any initial value is given theoretically and verified experimentally. Moreover, conditions on the control parameter and initial value are derived, ensuring the corresponding sequences to achieve the maximum period over the ring. The results can be used as ground truth for dynamical analysis and cryptographical applications of the logistic map over various domains.

As a highly toxic heavy metal ion, mercury ion (Hg2+) pollution has caused serious harm to the environment and human health. In this paper, 4-mercaptopyridine (4-MPY) was selected as the sensing material and decorated on the surface of a gold electrode. Trace Hg2+ could be detected by both differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) methods. The proposed sensor displayed a wide detection range from 0.01 μg/L to 500 μg/L with a low limit of detection (LOD) of 0.002 μg/L by EIS measurements. Combined with molecular simulations and electrochemical analyses, the chelating mechanism between Hg2+ and 4-MPY was explored. Through the analysis of binding energy (BE) values and stability constants, 4-MPY showed an excellent selectivity for Hg2+. In the presence of Hg2+, the coordination of Hg2+ with the pyridine nitrogen of 4-MPY was generated at the sensing region, which caused a change in the electrochemical activity of the electrode surface. Due to the strong specific binding capability, the proposed sensor featured excellent selectivity and an anti-interference capability. Furthermore, the practicality of the sensor for Hg2+ detection was validated with the samples of tap water and pond water, which demonstrated its potential application for on-site environmental detection.

A convenient and practical method for the synthesis of bioactive ester-containing chroman-4-ones through the cascade radical cyclization of 2-(allyloxy)arylaldehydes and oxalates is described. The preliminary studies suggest that an alkoxycarbonyl radical might be involved in the current transformation, which was generated via the decarboxylation of oxalates in the presence of (NH4)2S2O8.

Traditional eddy current technology identifies metal information with information of single frequency of limited frequency spectrum. To solve existing problems, this paper proposes a discrete wavelet transform-based metal material analysis model by using a constant phase angle pulse eddy current (CPA-PEC) sensor which collects and depicts metal feature information from multiple dimensions; then, the quantification calculation model of metal material by CPA-PEC feature is presented; finally, an experimental platform is built to collect the CPA-PEC features of various metal samples and verify recognition accuracy of the proposed metal material analysis model. In the investigation, 1000 eddy current signals from four standard metals (Cu, Fe, Al, St) and three types of metallic irons (Fe-K162, Fe-K163, Fe-K240) are measured and the features are identified by discrete wavelet transform. The feature correlation and significance are determined by regression analysis. Finally, the calculation model of feature evaluation index is present. The experimental analysis indicates that the stability of the quantitative evaluation index of eddy current features reaches 97.1%, the comprehensive accuracy error is less than 0.32% and the average measurement speed is about 50 ms for 1000 random sampling tests on standard metals.