Infection with 'Candidatus Liberibacter asiaticus' improves the fecundity of Diaphorina citri aiding its proliferation: A win-win strategy.

The evolution of insect vector-pathogen relationships has long been of interest in the field of molecular ecology. One system of special relevance, due to its economic impacts, is that between Diaphorina citri and 'Candidatus Liberibacter asiaticus' (CLas), the cause of the severe Asian form of huanglongbing. CLas-positive D. citri are more fecund than their CLas-negative counterparts, boosting opportunities for pathogens to acquire new vector hosts. The molecular mechanism behind this life-history shift remains unclear. Here, we found that CLas promoted ovarian development and increased the expression of the vitellogenin receptor (DcVgR) in ovaries. DcVgR RNAi significantly decreased fecundity and CLas titer in ovaries, extended the preoviposition period, shortened the oviposition period and blocked ovarian development. Given their importance in gene regulation, we explored the role of miRNAs in shaping these phenotypes and their molecular triggers. Our results showed that one miRNA, miR-275, suppressed DcVgR expression by binding to its 3' UTR. Overexpression of miR-275 knocked down DcVgR expression and CLas titer in ovaries, causing reproductive defects that mimicked DcVgR knockdown phenotypes. We focused, further, on roles of the Juvenile Hormone (JH) pathway in shaping the observed fecundity phenotype, given its known impacts on ovarian development. After CLas infection, this pathway was upregulated, thereby increasing DcVgR expression. From these combined results, we conclude that CLas hijacks the JH signalling pathway and miR-275, thereby targeting DcVgR to increase D. citri fecundity. These changes simultaneously increase CLas replication, suggesting a pathogen-vector host mutualism, or a seemingly helpful, but cryptically costly life-history manipulation.

Extracellular vesicles meet mitochondria: Potential roles in regenerative medicine.

Extracellular vesicles (EVs), secreted by most cells, act as natural cell-derived carriers for delivering proteins, nucleic acids, and organelles between cells. Mitochondria are highly dynamic organelles responsible for energy production and cellular physiological processes. Recent evidence has highlighted the pivotal role of EVs in intercellular mitochondrial content transfer, including mitochondrial DNA (mtDNA), proteins, and intact mitochondria. Intriguingly, mitochondria are crucial mediators of EVs release, suggesting an interplay between EVs and mitochondria and their potential implications in physiology and pathology. However, in this expanding field, much remains unknown regarding the function and mechanism of crosstalk between EVs and mitochondria and the transport of mitochondrial EVs. Herein, we shed light on the physiological and pathological functions of EVs and mitochondria, potential mechanisms underlying their interactions, delivery of mitochondria-rich EVs, and their clinical applications in regenerative medicine.

Cytokinin-deficient Chlamydomonas reinhardtii CRISPR-Cas9 mutants show reduced ability to prime resistance of tobacco against bacterial infection.

Although microalgae have only recently been recognized as part of the plant and soil microbiome, their application as biofertilizers has a tradition in sustainable crop production. Under consideration of their ability to produce the plant growth-stimulating hormone cytokinin (CK), known to also induce pathogen resistance, we have assessed the biocontrol ability of CK-producing microalgae. All pro- and eukaryotic CK-producing microalgae tested were able to enhance the tolerance of tobacco against Pseudomonas syringae pv. tabaci (PsT) infection. Since Chlamydomonas reinhardtii (Cre) proved to be the most efficient, we functionally characterized its biocontrol ability. We employed the CRISPR-Cas9 system to generate the first knockouts of CK biosynthetic genes in microalgae. Specifically, we targeted Cre Lonely Guy (LOG) and isopentenyltransferase (IPT) genes, the key genes of CK biosynthesis. While Cre wild-type exhibits a strong protection, the CK-deficient mutants have a reduced ability to induce plant defence. The degree of protection correlates with the CK levels, with the IPT mutants showing less protection than the LOG mutants. Gene expression analyses showed that Cre strongly stimulates tobacco resistance through defence gene priming. This study functionally verifies that Cre primes defence responses with CK, which contributes to the robustness of the effect. This work contributes to elucidate microalgae-mediated plant defence priming and identifies the role of CKs. In addition, these results underscore the potential of CK-producing microalgae as biologicals in agriculture by combining biofertilizer and biocontrol ability for sustainable and environment-friendly crop management.

Occurrence of Maize Leaf Spot Disease Caused by Leptosphaerulina australis in Yunnan, China.

Maize (Zea mays) is vital as a staple food and livestock feed crop. Yunnan is one of the main maize-producing provinces in China (National Bureau of Statistics, 2022). While corn production in Yunnan is lower than the national average, the development of drought-tolerant varieties has contributed to improving productivity. In August 2021, a new leaf spot disease on maize was observed in Lancang, Yunnan (22°26'38.11"N to 22°48'38.68"N, 99°48'15.13"E to 99°59'20.03"E), causing serious damages to maize production with incidence up to 76.19 %. Initially, small light yellow lesions were seen scattered on diseased maize leaves, round or polygon, measuring 0.3 to 2.0 cm in diameter. In the intermediate phase, these lesions sank, ruptured, and turned white with dark brown borders. In severe cases, they merged into large irregular patches, reaching up to 10 cm, leading to complete leaf necrosis. Small black ascomata were seen on the lesions. Tissue sections reveal perithecium embedded in leaves, measuring 94~145 µm in diameter. Symptomatic tissues were sterilized in 1.5% NaClO for 60s, and washed twice withsterile purified water, then plated on potato dextrose agar (PDA) at 25℃, 90% relative humidity (RH), and a 12-hour light cycle. 6 isolates were obtained from 2 diseased maize cultivars. In 20 days, the colony reached the edge of the PDA plate, the center darkening from white, featuring white aerial mycelium on top and black on the reverse side. Brown ascomata, solitary or clustered, measured 80.1~176.7 × 55.57~138.9 µm. The ellipsoid to oblong ascospores were 17.9~39.7 × 10.9~14.1 µm, and the bitunicate, thick-walled asci were 90.1~133.3 × 26.6~33.5 µm. The genomic DNA was extracted using the Chelex-100 method (Möller et al. 1992). For molecular identification, the ITS, LSU, and ß-tubulin (Tub2) genes were amplified using primer pairs ITS1/ITS4 (White et al. 1990), LR0R/LR5 (Vilgalys et al. 1990) and Btub2Fd/Btub4Rd (Woudenberg et al. 2009), respectively. Sequencing was performed by Sangon Biotech (Shanghai) Co., Ltd. The sequenced loci (GenBank accession nos.: LSU, OL687348-53; ITS, OL617009-10, and OL664058-61; Tub2, OL741678-83) of the isolates exhibited 100%/ 99%/ 100% similarities with L. australis genes: LSU, MH868885; ITS, KF381084; Tub2, GU237541, respectively. Using MEGA 11.0, phylogenetic trees were constructed using the maximum-likelihood algorithm on concatenated sequences of LSU, ITS, and Tub2 for isolates LCMB1 to 6. The isolates clustered with two L. australis strains with 100 % bootstrap support (1,000 replicates). The results were consistent with the Bayesian Inference tree. The pathogenicity test used strain LCMB4 on six healthy maize plants during the heading period under natural conditions. Three leaves pre-plant were wounded with sterile sandpaper and sprayed with conidial suspension (106 spores ml-1, diluted in sterilized water) in the greenhouse at 28℃, 90% RH, and a 12-hour light cycle, with sterilized distilled water used for control. Inoculated leaves developed symptoms consistent with the described after 10 days, while control leaves remained symptomless. The same pathogen was re-isolated from the infected leaves, fulfilling Koch's postulates. Previously, L. australis has been isolated from turfgrass (Mitkowski et al. 2004), Alfalfa (Zhang et al. 2021), soil (Li et al. 2018), and Paris polyphylla var. chinensis (Fu et al. 2019), but not from maize. This is the first report of L. australis causing leaf spot on maize globally.

Activating α7nAChR helps post-myocardial infarction healing by regulating macrophage polarization via the STAT3 signaling pathway.

BACKGROUND: Monocytes/macrophages play critical roles in inflammation and cardiac remodeling following myocardial infarction (MI). The cholinergic anti-inflammatory pathway (CAP) modulates local and systemic inflammatory responses by activating α7 nicotinic acetylcholine receptors (α7nAChR) in monocytes/macrophages. We investigated the effect of α7nAChR on MI-induced monocyte/macrophage recruitment and polarization and its contribution to cardiac remodeling and dysfunction. METHODS: Adult male Sprague Dawley rats underwent coronary ligation and were intraperitoneally injected with the α7nAChR-selective agonist PNU282987 or the antagonist methyllycaconitine (MLA). RAW264.7 cells were stimulated with lipopolysaccharide (LPS) + interferon-gamma (IFN-γ) and treated with PNU282987, MLA, and S3I-201 (a STAT3 inhibitor). Cardiac function was evaluated by echocardiography. Masson's trichrome and immunofluorescence were used to detect cardiac fibrosis, myocardial capillary density, and M1/M2 macrophages. Western blotting was used to detect protein expression, and the proportion of monocytes was measured using flow cytometry. RESULTS: Activating the CAP with PNU282987 significantly improved cardiac function and reduced cardiac fibrosis and 28-day mortality after MI. On days 3 and 7 post-MI, PNU282987 reduced the percentage of peripheral CD172a + CD43low monocytes and the infiltration of M1 macrophages in the infarcted hearts, whereas it increased the recruitment of peripheral CD172a + CD43high monocytes and M2 macrophages. Conversely, MLA exerted the opposite effects. In vitro, PNU282987 inhibited M1 macrophage polarization and promoted M2 macrophage polarization in LPS + IFN-γ-stimulated RAW264.7 cells. These PNU282987-induced changes in LPS + IFN-γ-stimulated RAW264.7 cells were reversed by administering S3I-201. CONCLUSION: Activating α7nAChR inhibits the early recruitment of pro-inflammatory monocytes/macrophages during MI and improves cardiac function and remodeling. Our findings suggest a promising therapeutic target for regulating monocyte/macrophage phenotypes and promoting healing after MI.

Spatial Distribution and Temporal Dynamics of Candidatus Liberibacter Asiaticus in Different Stages of Embryos, Nymphs and Adults of Diaphorina citri.

Huanglongbing, a globally devastating citrus disease, is associated with Candidatus Liberibacter asiaticus (CLas) and is mainly transmitted by Diaphorina citri. Verification of the distribution and dynamics of CLas in D. citri is critical to understanding CLas transmitted by vectors in nature. Here, the distribution and titers of CLas in different sexes and tissues of D. citri adults were investigated by fluorescence in-situ hybridization (FISH) and quantitative real-time PCR (qRT-PCR). Results showed that CLas had widespread distribution in the brain, salivary glands, digestive system, and reproductive system of both females and males, indicating a systemic infection of CLas in D. citri. Moreover, CLas fluorescence intensity and titers were significantly increased in both the digestive system and the female reproductive system with development and there was a marked decreased in both the salivary glands and the male brain, but there was no significant change in the female brain or the male reproductive system. Furthermore, the distribution and dynamics of CLas in embryos and nymphs were investigated. CLas was observed in all laid eggs and subsequent first-second-instar nymphs, indicating that a high percentage of embryos and nymphs resulting from infected D. citri mothers were infected with CLas.

A Shape-Programmable Hierarchical Fibrous Membrane Composite System to Promote Wound Healing in Diabetic Patients.

Chronic wound infection is one of the critical complications of diabetes and is difficult to cure. Although great efforts have been made, the development of special dressings that serve as therapeutic strategies to effectively promote wound healing in diabetic individuals remains a major challenge. In this study, a shape-programmable hierarchical fibrous membrane composite system is developed for synergistic modulation of the inflammatory microenvironment to treat chronically infected wounds. The system comprises a functional layer and a shape-programmable backing layer. A temperature-responsive shape-memory mechanism achieves biaxial mechanically active contractions of diabetic wounds in a programmable manner. To summarize, the membrane system combines antimicrobial activity, controlled drug release according to the need of wound healing, mechanical modulation with shape-programmable, robust adhesion, and on-demand debonding to biological tissue to rationally guide chronic wound management. A synergistic combination of antibacterial fiber network and released drugs shows broad-spectrum antibacterial activity. In vitro and in vivo evaluations indicate the dressing efficiency in promoting and supporting wound healing. The insights from this study demonstrate the effectiveness of a hierarchical composite membrane system with shape-programmability as a potential treatment in the care of diabetic wounds.

G-quadruplex-selective iridium(III) complex as a novel electrochemiluminescence probe for switch-on assay of double-stranded DNA.

In this work, we synthesized an iridium(III) complex and studied its selective ability to interact with a specific G-quadruplex DNA sequence (GTGGGTAGGGCGGGTTGG). Results showed that the iridium(III) complex exhibits high selectivity for the G-quadruplex DNA and could be used as an efficient electrochemiluminescence (ECL) probe in a switch-on assay format for the detection of double-stranded DNA (dsDNA). To construct the assay, a hairpin-structured capture probe (CP) which was modified by thiol at its 3' end and contained the G-quadruplex sequence at its 5' end was firstly immobilized on a gold electrode. Upon the specific recognition of the dsDNA sequence with the corresponding CP, the hairpin structure of the CP was opened to free G-quadruplex sequence, forming the G-quadruplex structure with the assistance of K+. Then, the iridium(III) complex was able to specifically interact with the G-quadruplex to produce an obvious ECL signal that was proportional to the dsDNA concentration. Notably, this iridium(III) complex/G-quadruplex-based strategy was universal and was not limited to the analysis of DNA using specific sequences, thus opening a new avenue for the application of the G-quadruplex-selective iridium(III) complex in the field of ECL.

An Automatic Defect Detection System for Petrochemical Pipeline Based on Cycle-GAN and YOLO v5.

Defect detection of petrochemical pipelines is an important task for industrial production safety. At present, pipeline defect detection mainly relies on closed circuit television method (CCTV) to take video of the pipeline inner wall and then detect the defective area manually, so the detection is very time-consuming and has a high rate of false and missed detections. To solve the above issues, we proposed an automatic defect detection system for petrochemical pipeline based on Cycle-GAN and improved YOLO v5. Firstly, in order to create the pipeline defect dataset, the original pipeline videos need pre-processing, which includes frame extraction, unfolding, illumination balancing, and image stitching to create coherent and tiled pipeline inner wall images. Secondly, aiming at the problems of small amount of samples and the imbalance of defect and non-defect classes, a sample enhancement strategy based on Cycle-GAN is proposed to generate defect images and expand the data set. Finally, in order to detect defective areas on the pipeline and improve the detection accuracy, a robust defect detection model based on improved YOLO v5 and Transformer attention mechanism is proposed, with the average precision and recall as 93.10% and 90.96%, and the F1-score as 0.920 on the test set. The proposed system can provide reference for operators in pipeline health inspection, improving the efficiency and accuracy of detection.

MoO3 Nanobelt-Modified HMCM-49 Zeolite with Enhanced Dispersion of Mo Species and Catalytic Performance for Methane Dehydro-Aromatization.

The methane dehydro-aromatization reaction (MDA) is a promising methane valorization process due to the conversion of methane to value-added aromatics (benzene, toluene and naphthalene). However, one of the major disadvantages of utilizing zeolite in MDA is that the catalyst is rapidly inactivated due to coke formation, which eventually causes the activity and aromatic selectivity to decrease. Consequently, the process is not conducive to large-scale industrial applications. The reasonable control of Mo site distribution on the zeolite surface is the key factor for partially inhibiting the coking of the catalyst and improving stability. Here, MoO3 nanobelts can be used for alternative Mo precursors to prepare MDA catalysts. Catalysts modified with MoO3 nanobelts present higher activity (13.4%) and benzene yield (9.2%) than those catalysts loaded with commercial MoO3.

A case of hyperhaemolysis syndrome in a pregnant Chinese woman with ß-thalassemia during perinatal transfusion.

OBJECTIVES: To report a case of hyperhaemolysis syndrome (HHS) that occurred during perinatal blood transfusion in a pregnant Chinese woman with ß-thalassemia to deepen the understanding of HHS and the risk of transfusion therapy for patients with thalassemia. BACKGROUND: Most HHS cases occur in people with sickle cell disease. So far, no cases of HHS have been reported in the Chinese population. Here, we report a pregnant Chinese women with ß-thalassemia experiencing HHS. METHODS: The patient received ABO- and RhD-matched red blood cell transfusion from six blood donors in four perinatal transfusions. Haemoglobinuria and lower haemoglobin levels compared to those before transfusion were observed after each transfusion, and the lactate dehydrogenase was consistently elevated. The blood samples were collected at different time points during the hospitalisation for direct antiglobulin test (DAT), antibody screening test and acid elution test. The antigens of six blood donors were identified, and the cross-matching tests were repeated using the blood sample of the patient with specific irregular antibodies after the last transfusion. RESULTS: The DAT of the patient was negative for anti-IgG and positive (1+) for anti-C3d, and no red blood cell antibodies were detected in the eluent before, between and after transfusions. Before and between transfusions, blood samples were negative for red blood cell irregular antibodies, whereas IgM anti-P1 and IgG anti-Jka were detected in blood samples the next day after the last transfusion. In the six donors, two were negative for P1 and Jka , one was positive for P1 and negative for Jka , and three were negative for P1 and positive for Jka . The tentative cross-matching tests using the indirect antiglobulin method in saline showed that only agglutination occurred in the blood samples of the patient collected after last transfusion and the three Jka -positive blood donors. DISCUSSION: The clinical manifestations and laboratory test results suggested that HHS occurred in this patient with ß-thalassemia after each transfusion. Clinicians should be aware that HHS can occur with compatible blood transfusion.

One-step and ultrasensitive ATP detection by using positively charged nano-gold@graphene oxide as a versatile nanocomposite.

A versatile nanocomposite was simply prepared based upon the electrostatic adsorption of positively charged gold nanoparticles with negatively charged graphene oxide (nano-gold@GO), and utilized as a novel fluorescence quenching platform for ultrasensitive detection of adenosine triphosphate (ATP). In the designed system, DNA-stabilized Ag nanoclusters (DNA/AgNCs) were used as fluorescent probes, DNA duplex was formed in the presence of ATP, and they can electrostatically adsorb onto the surface of nano-gold@GO to quench the fluorescence signal. Upon the addition of exonuclease III (Exo III), the DNA duplex would be hydrolyzed into DNA fragments and resulted in the recovery of the fluorescence signals due to the diffusion of AgNCs away from nano-gold@GO. Based on these, sensitive detection of ATP was realized with a detection range of 5.0 pM-20 nM. Notably, a good recovery in the range of 94-104% was obtained when detecting ATP in human serum samples, indicating a promising application value in early disease diagnosis. Graphical abstract A functional positively charged nano-gold@graphene oxide was fabricated and utilized as an enhanced fluorescence quenching platform for the detection of ATP, coupled with exonuclease III-assisted signal amplification.

CB1 receptor antagonist rimonabant protects against chronic intermittent hypoxia-induced bone metabolism disorder and destruction in rats.

OBJECTIVE: The endocannabinoid system (ECS) regulates bone turn-over and remodeling. Chronic intermittent hypoxia (CIH) occurring during obstructive sleep apnea (OSA) may lead to disorders of the ECS and bone metabolism abnormalities. This study aimed to investigate whether or not the cannabinoid receptor 1 (CB1R) antagonist rimonabant (Ri) alleviates bone metabolism abnormalities and bone destruction induced by chronic intermittent hypoxia (CIH). METHODS: Healthy male Sprague Dawley (SD) rats (n=48) were randomly divided into 6 groups of 8 rats: 2 normal control (NC) groups, 2 intermittent hypoxia (IH) groups, and 2 IH + Ri groups. Rats in NC groups breathed room air for 4 weeks (4w NC group) and 6 weeks (6w NC group). Rats in IH groups experienced IH environment for 4 weeks (4w IH group) and 6 weeks (6w IH group). In addition to the same IH exposure, rats in IH + Ri group were given daily intraperitoneal injection of Ri at the dosage of 1.5 mg/kg/d for 4 weeks (4w IH + Ri group) and 6 weeks (6w IH + Ri group). Levels of serum tartrate-resistant acid phosphatase (TRAP, a marker of bone resorption) were determined by ELISA. Hematoxylin and eosin (HE) staining was performed on bone sections to observe the changes in bone microstructure. Expression of CB1R in bone tissue was determined by immunohistochemistry. RESULTS: TRAP levels were higher in the 4w IH and 6w IH groups than in the 4w NC and 6w NC groups; TRAP levels were lower in the 4w IH + Ri and 6w IH + Ri groups than in the 4w IH and 6w IH groups. HE staining showed that the morphology of bone cells in the NC group was normal, but the 4w IH group had mild edema of bone cells, reduction in trabecular bone, and destruction of bone microstructure. Changes were more severe in the 6w IH group than 4w IH. The 4w IH + Ri group was slightly improved compared with the 4w IH group. The 6w IH + Ri group was improved compared with the 4w IH + Ri group. The results of immunohistochemistry showed that the expression of CB1R in IH group was significantly higher than that in NC group. The expression of CB1R in the IH + Ri group was lower than that in the IH group. With the prolongation of hypoxia, the expression of CB1R in bone cells of IH group increased. The expression level of CB1R in IH + Ri group decreased with the prolongation of intervention time. Correlation analysis showed that the expression rate of CB1R in bone cells was positively correlated with the level of TRAP in serum. CONCLUSION: CIH increases serum TRAP levels and triggers metabolic bone disorder by activating bone CB1R. Intervention with CB1R antagonist (rimonabant) reduces the bone dysmetabolism in the CIH rat model.

Eliciting α7-nAChR exerts cardioprotective effects on ischemic cardiomyopathy via activation of AMPK signalling.

Our previous studies have reported that agonist of α7 nicotinic acetylcholine receptors prevented electrophysiological dysfunction of rats with ischaemic cardiomyopathy (ICM) by eliciting the cholinergic anti-inflammatory pathway (CAP). Adenosine monophosphate-activated protein kinase (AMPK) signalling is widely recognized exerting cardioprotective effect in various cardiomyopathy. Here, we aimed to investigate whether the protective effects of the CAP are associated with AMPK signalling in ICM. In vivo, coronary artery of rats was ligated for 4 weeks to induce the ICM and then treated with PNU-282987 (CAP agonist) and BML-275 dihydrochloride (AMPK antagonist) for 4 weeks. In vitro, primary macrophages harvested from rats were induced inflammation by Lipopolysaccharide (LPS) treatment and then treated with PNU-282987 and BML-275 dihydrochloride. In vivo, exciting CAP by PUN-282987 elicited an activation of AMPK signalling, alleviated ventricular remodeling, modified the cardiac electrophysiological function, reduced the cardiac expression of collagens and inflammatory cytokines and maintained the integrity of ultrastructure in the ischemic heart. However, the benefits of CAP excitation were blunted by AMPK signaling antagonization. In vitro, excitation of the CAP was observed inhibiting the nuclear transfer of NF-κB p65 of macrophages and promoting the transformation of Ly-6Chigh macrophages into Ly-6Clow macrophages. However, inhibiting AMPK signalling by BML-275 dihydrochloride reversed the CAP effect on LPS-treated macrophages. Finally, our findings suggest that eliciting the CAP modulates the inflammatory response in ICM through regulating AMPK signalling.

Electrochemical aptamer-based determination of protein tyrosine kinase-7 using toehold-mediated strand displacement amplification on gold nanoparticles and graphene oxide.

An electrochemical method is described for ultrasensitive determination of protein tyrosine kinase-7 (PTK7). It is based on (a) the use of positively charged gold nanoparticles (AuNPs) and negatively charged graphene oxide (GO), and (b) of toehold-mediated strand displacement amplification. A hairpin probe 2 (HP2) containing the sgc8 aptamer was used to modify a glassy carbon electrode (GCE). Its hairpin structure is opened in the presence of PTK7 to form the PTK7-HP2 complex. The exposed part of HP2 partly hybridizes with hairpin probe 1 (HP1) that was immobilizing on the AuNPs and GO modified GCE. On addition of the hairpin probe 3 that was labeled with the redox probe Methylene Blue (MB-HP3), toehold-mediated strand displacement occurs due to complementary hybridization of HP1 with MB-HP3. This causes the release of PTK7-HP2 into the solution and makes it available for the next reaction. Under optimal conditions, PTK7 can be quantified by voltammetry (typically performed at -0.18 V) with a detection limit of 1.8 fM. The assay possesses high selectivity for PTK7 due to the employment of the aptamer. It was successfully applied to the determination of PTK7 in the debris of malignant melanoma A375 cells. Graphical abstract Schematic representation of the enzyme-free electrochemical sensor for ultrasensitive determination of protein tyrosine kinase-7 (PTK7) based on the toehold-mediated strand displacement reaction amplification on gold nanoparticles and graphene oxide.

Fluorometric determination of mercury(II) using positively charged gold nanoparticles, DNA-templated silver nanoclusters, T-Hg(II)-T interaction and exonuclease assisted signal amplification.

The authors describe a method for detection of Hg2+ by using positively charged gold nanoparticles ((+)AuNPs) as a quencher of the fluorescence of DNA-capped silver nanoclusters (DNA-AgNCs) which are negatively charged. In the presence of Hg2+, a DNA duplex is formed through T-Hg2+-T coordination chemistry. The duplex can be digested by exonuclease III to form smaller DNA fragments. This leads to the release of the AgNCs and the recovery of fluorescence, best measured at excitation/emission wavelengths of 460/530 nm. The (+)AuNPs and Hg2+ are also released and can be reused for target recycling signal amplification. Based on these findings, a method is worked out for the determination of Hg2+ that works in the 5.0 pM to 10 nM concentration range and has a detection limit as low as 2.3 pM. It is highly selective because of the highly specific formation of T-Hg2+-T bonds. Graphical abstract By using ultrastable and positively charged gold nanoparticles as fluorescence quenchers and exonuclease assisted signal amplification, a method is developed for the sensitive and selective detection of Hg2+ in water samples.

Role of the endogenous cannabinoid receptor 1 in brain injury induced by chronic intermittent hypoxia in rats.

PURPOSE: This study investigated the effect of rimonabant, a cannabinoid receptor type 1 antagonist, on calcium/calmodulin- dependent protein kinase II and cannabinoid receptor type 1 in chronic intermittent hypoxia. MATERIALS AND METHODS: Healthy male rats were divided into control group, intermittent hypoxia group for 4 or 6 weeks, hypoxic intervention group that received rimonabant (1 mg/kg/d) before exposure to hypoxia for 4 or 6 weeks (n = 10/group). Morphological changes and expressions of the two indexes in the cerebral hippocampus cells were determined by haematoxylin-eosin staining and immunohistochemistry, respectively. RESULTS: In the intermittent hypoxia group at 4 weeks, the hippocampal cells were damaged with sparse cytoplasm and unclear boundaries, which are even worse at 6 weeks. In contrast, the hippocampal cells of the hypoxic intervention group were neatly arranged at 4 weeks. At 6 weeks, cells were larger with scarce cytoplasm and nuclear changes indicative of cell death. Calcium/calmodulin-dependent protein kinase II and cannabinoid receptor type 1 expression in the cerebral hippocampus was elevated in the intermittent hypoxia group at 4 weeks with even greater at 6 weeks. Cannabinoid receptor type 1 expression was reduced in the hypoxic intervention group compared to the intermittent hypoxia group. Correlation analysis revealed significant positive correlation of them in the intermittent hypoxia group. CONCLUSIONS: Chronic intermittent hypoxia induced structural damage in the hippocampus and increased cannabinoid receptor type 1 and calcium/calmodulin-dependent protein kinase II expression, which may mediate cognitive impairment associated with chronic intermittent hypoxia. Rimonabant had a protective effect against chronic intermittent hypoxia.

Approach selection of radiofrequency catheter ablation for ventricular arrhythmias originating from the left ventricular summit: potential relevance of Pseudo Delta wave, Intrinsicoid deflection time, maximal deflection index.

BACKGROUND: Ventricular arrhythmias (VAs) originating from the left ventricular summit is a challenge for radiofrequency catheter ablation (RFCA). The present study aimed to investigate the appropriate RFCA strategy for VAs originating from the left ventricular summit. METHODS: Forty-five consecutive patients with VAs arising from the left ventricular summit were successfully ablated at our cardiac electrophysiology center and reviewed in the study. RESULTS: Thirty-two cases of VAs were eliminated in the left ventricular endocardium by retrograde transaortic (n = 22, 22/45, 48.9%) or antegrade transseptal (n = 10, 10/45, 22.2%) approaches, the other 13 cases were eliminated in the left ventricular epicardium by distal great cardiac vein (DGCV) approach (n = 13, 13/45, 28.9%). Though these VAs were similar in electrocardiographic (ECG) morphology, the pseudo delta waves (PDW), intrinsicoid deflection time (IDT), maximal deflection index (MDI) differed among them, PDW >53 ms, IDT > 74 ms, MDI > 0.45 strongly indicated that ablating left ventricular summit VAs by DGCV approach. During mean follow-up of 19.5 ± 13.2 (range, 3-60) months, 2 (4.4%) patients experienced VAs recurrence. CONCLUSION: This retrospective study showed that VAs of left ventricular summit origin can be effectively cured with RFCA. For these VAs, prolonged PdW, IDT, MDI indicating RFCA by DGCV approach can be attempted firstly.

Origins location of the outflow tract ventricular arrhythmias exhibiting qrS pattern or QS pattern with a notch on the descending limb in lead V1.

BACKGROUND: Ventricular outflow tract(VOT) ventricular arrhythmias(VAs) presenting qrS pattern or QS pattern with a notch on the descending limb in lead V1 were consistently thought of arising from the commissure between left and right coronary cusp (L-RCC) by previous studies. However, we found they could originate from other anatomic structures in VOT. This study aimed to investigate the exact origin of this kind VAs. METHODS: Forty-nine patients of VOT premature ventricular contrations/ventricular tachycardia(PVCs/VT) with lead V1 presenting qrS pattern or QS pattern with a notch on the descending limb undergoing successful radiofrequency catheter ablation(RFCA) in our center were analyzed. RESULTS: 12-lead electrocardiogram(ECG) of these PVCs/VT were summarized. Among these PVCs/VT, 37 cases exhibited qrS morphology in lead V1, 12 cases presented QS pattern with a notch on the descending limb in the same lead. Based on the successful ablation sites, these PVCs/VT were divided into 2 groups: (1)Right ventricular outflow tract(RVOT) group (26 cases), and (2) Left ventricular outflow tract (LVOT) group(23 cases, 4 cases originating from the left coronary cusp(LCC), 2 from the right coronary cusp(RCC), 16 from the L-RCC, 1 from the area inferior to LCC(ILCC)). The ECG characteristics of each PVCs/VT were analyzed. Among these PVCs/VT, applying the precordial transitional zone index(TZ index) < 0 to predict LVOT origin was demonstrated with sensitivity of 95.65%, specificity of 96.15%, positive predicting value(PPV) of 95.65% and negative predicting value(NPV) of 96.15%. In LVOT group, further applying the r, R, m,or Rs morphology in lead I to predict L-RCC and RCC origin was demonstrated with sensitivity of 94.44%, specificity of 60.00%, PPV of 89.47% and NPV of 75.00%. CONCLUSIONS: Ventricular outflow tract PVCs/VT with lead V1 presenting qrS pattern or QS pattern with a notch on descending limb not only arising from L-RCC, but also RVOT, LCC, RCC and ILCC. Combining TZ index and QRS morphology in lead I to predict origin site of these kind VAs is a convenient, simple and reliable method and facilitates the RFCA procedure.

Assessing EFL (English as Foreign Language) Education for Sustainable Development: Exploring the Cultural Teaching Literature.

Cultural teaching is the underlying core component of English as Foreign Language (EFL) education. Although the previous literature has intensely studied this theme, a comprehensive bibliometric analysis of research characteristics and trends in this field is still lacking regarding cultural teaching in EFL education. This study aims to explore the research distribution, research hot topics, and research the trends of EFL cultural teaching by conducting a bibliometric analysis of 358 articles on Web of Science using CiteSpace. The analysis leads to the following three findings: (a) The countries that teach EFL prevail in terms of number of publications but lag behind in terms of research influence, and a global academic community has not taken shape. (b) Interculturality is the central theme, encompassing a range of related topics such as intercultural competence, intercultural communication, and cultural awareness, with key teachers, learners, and textbooks as research perspectives. (c) Multilingual turn has emerged as a prominent new trend, which emphasizes the importance of cultural diversity and pays more attention to source/native languages and cultures. Furthermore, possible measures of promoting interculturality were discussed on the basis of relevant literature studies. In addition, scholars are suggested to pay more academic attention to the research and practices of EFL countries.