A comprehensive workflow for optimizing RNA-seq data analysis.

BACKGROUND: Current RNA-seq analysis software for RNA-seq data tends to use similar parameters across different species without considering species-specific differences. However, the suitability and accuracy of these tools may vary when analyzing data from different species, such as humans, animals, plants, fungi, and bacteria. For most laboratory researchers lacking a background in information science, determining how to construct an analysis workflow that meets their specific needs from the array of complex analytical tools available poses a significant challenge. RESULTS: By utilizing RNA-seq data from plants, animals, and fungi, it was observed that different analytical tools demonstrate some variations in performance when applied to different species. A comprehensive experiment was conducted specifically for analyzing plant pathogenic fungal data, focusing on differential gene analysis as the ultimate goal. In this study, 288 pipelines using different tools were applied to analyze five fungal RNA-seq datasets, and the performance of their results was evaluated based on simulation. This led to the establishment of a relatively universal and superior fungal RNA-seq analysis pipeline that can serve as a reference, and certain standards for selecting analysis tools were derived for reference. Additionally, we compared various tools for alternative splicing analysis. The results based on simulated data indicated that rMATS remained the optimal choice, although consideration could be given to supplementing with tools such as SpliceWiz. CONCLUSION: The experimental results demonstrate that, in comparison to the default software parameter configurations, the analysis combination results after tuning can provide more accurate biological insights. It is beneficial to carefully select suitable analysis software based on the data, rather than indiscriminately choosing tools, in order to achieve high-quality analysis results more efficiently.

Etching of Ag nanoparticles triggered bidirectional regulation for electrochemiluminescence ratiometric immunoassay.

A highly efficient ratiometric electrochemiluminescence (ECL) immunoassay was explored by bidirectionally regulating the ECL intensity of two luminophors. The immunoassay was conducted in a split-type mode consisting of an ECL detection procedure and a sandwich immunoreaction. The ECL detection was executed using a dual-disk glassy carbon electrode modified with two potential-resolved luminophors (g-C3N4-Ag and Ru-MOF-Ag nanocomposites), and the sandwich immunoreaction using glucose oxidase (GOx)-modified SiO2 nanospheres as labels was carried out in a 96-well plate. The Ag nanoparticles (NPs) acted as bifunctional units both for triggering the resonance energy transfer (RET) with g-C3N4 and for accelerating the electron transfer rate of the Ru-MOF-Ag ECL reaction. When the H2O2 catalyzed by GOx in the 96-well plate was transferred to the dual-disk glass carbon electrode, the doped Ag NPs in the two luminophors could be etched, thus destroying the RET between C3N4 and the accelerated reaction to Ru-MOF, resulting in an opposite trend in the ECL signal outputted from the dual disks. Using the ratio of the two signals for quantification, the constructed immunosensor for a model target, i.e. myoglobin, exhibited a low detection limit of 4.7 × 10-14 g/mL. The ingenious combination of ECL ratiometry, bifunctional Ag NPs, and a split-type strategy effectively reduces environmental and human errors, offering a more precise and sensitive analysis for complex samples.

Studies on the Biomimetic Synthesis of Marine Ladder Polyethers via Endo-Selective Epoxide-to-Epoxonium Ring-Opening Cascades.

Marine ladder polyethers have attracted the attention of chemists and biologists because of their potent biological activities. Synthetic chemists have attempted to construct their polyether frameworks by epoxide ring-opening cascades, as Nakanishi hypothesis describes. However, Baldwin's rules of ring closure state that exo-selective intramolecular cyclization of epoxy alcohols is preferred over endo-selective cyclization. Herein, we investigated epoxide ring-opening cascades of polyepoxy alcohols in [EMIM]BF4/PFTB (1-ethyl-3-methylimidazolium tetrafluoroborate /perfluoro-tert-butyl alcohol) and found that all-endo products were formed via epoxide-to-epoxonium ring-opening cyclizations (not restricted by Baldwin's rules, which only apply to intramolecular hydroxyl-to-epoxide cyclizations). We determined that the key factor enabling polyepoxy alcohols to undergo a high proportion of all-endo-selective cyclization was inhibition of exo-selective hydroxyl-to-epoxide cyclization starting from the terminal hydroxyl group of a polyepoxy alcohol. By introducing a slow-release protecting group to the terminal hydroxyl group, we could markedly increase the cyclization yields of polyether fragments with hydrogen atoms at the ring junctions. For the first time, we constructed consecutively fused six-membered-ring and fused seven-, eight-, and nine-membered-ring polyether fragments by epoxide-to-epoxonium ring-opening cyclizations through the addition of a suitable Lewis acid. We also suggest that the biosynthesis of marine ladder polyethers may proceed via epoxide-to-epoxonium ring-opening cyclization of polyepoxide.

Identification of WUSCHEL-related homeobox gene and truncated small peptides in transformation efficiency improvement in Eucalyptus.

BACKGROUND: The WUSCHEL-related Homeobox (WOX) genes, which encode plant-specific homeobox (HB) transcription factors, play crucial roles in regulating plant growth and development. However, the functions of WOX genes are little known in Eucalyptus, one of the fastest-growing tree resources with considerable widespread cultivation worldwide. RESULTS: A total of nine WOX genes named EgWOX1-EgWOX9 were retrieved and designated from Eucalyptus grandis. From the three divided clades marked as Modern/WUS, Intermediate and Ancient, the largest group Modern/WUS (6 EgWOXs) contains a specific domain with 8 amino acids: TLQLFPLR. The collinearity, cis-regulatory elements, protein-protein interaction network and gene expression analysis reveal that the WUS proteins in E. grandis involve in regulating meristems development and regeneration. Furthermore, by externally adding of truncated peptides isolated from WUS specific domain, the transformation efficiency in E. urophylla × E. grandis DH32-29 was significant enhanced. The transcriptomics data further reveals that the use of small peptides activates metabolism pathways such as starch and sucrose metabolism, phenylpropanoid biosynthesis and flavonoid biosynthesis. CONCLUSIONS: Peptides isolated from WUS protein can be utilized to enhance the transformation efficiency in Eucalyptus, thereby contributing to the high-efficiency breeding of Eucalyptus.

Comprehensive analysis of the PTPN13 expression and its clinical implication in breast cancer.

Protein tyrosine phosphatases non-receptor 13 (PTPN13) could be a potential biomarker in breast cancer (BRCA), but its genetic variation and biological significance in BRCA remain undefined. Hereon, we comprehensively investigated the clinical implication of PTPN13 expression/gene mutation in BRCA. In our study, a total of 14 cases of triple-negative breast cancers (TNBC) treated with neoadjuvant therapy were enrolled, and post-operation TNBC tissues were collected for next-generation sequencing (NGS) analysis (422 genes including PTPN13). According to the disease-free survival (DFS) time, 14 TNBC patients were divided into Group A (long-DFS) and Group B (short-DFS). The NGS data displayed that the overall mutation rate of PTPN13 was 28.57% as the third highest mutated gene, and PTPN13 mutations appeared only in Group B with short-DFS. In addition, The Cancer Genome Atlas (TCGA) database demonstrated that PTPN13 was lower expressed in BRCA than in normal breast tissues. However, PTPN13 high expression was identified to be related to a favorable prognosis in BRCA using data from the Kaplan-Meier plotter. Moreover, Gene Set Enrichment Analysis (GSEA) revealed that PTPN13 is potentially involved in interferon signaling, JAK/STAT signaling, Wnt/ß-catenin signaling, PTEN pathway, and MAPK6/MAPK4 signaling in BRCA. This study provided evidence that PTPN13 might be a tumor suppressor gene and a potential molecular target for BRCA, and genetic mutation and/or low expression of PTPN13 predicted an unfavorable prognosis in BRCA. The anticancer effect and molecular mechanism of PTPN13 in BRCA may be associated with some tumor-related signaling pathways.

Persistence of Detectable Anti-Pneumococcal Antibodies 4 Years After Pneumococcal Polysaccharide Vaccination in a Randomised Controlled Trial: The Australian Study for the Prevention through Immunisation of Cardiovascular Events (AUSPICE).

AIM: Mouse models have indicated that the pneumococcal polysaccharide vaccine (PPV) can reduce atherosclerosis. This is probably through a process of molecular mimicry, where phosphorylcholine in the capsular polysaccharide of the vaccine elicits antibodies that cross-react with oxidised low-density lipoprotein and reduce plaque. We investigated whether a similar mechanism occurs in humans. METHODS: A large national blinded, randomised, placebo-controlled trial of the PPV (Australian Study for the Prevention through Immunisation of Cardiovascular Events [AUSPICE]) is underway with fatal and nonfatal cardiovascular disease (CVD) events as the primary outcome. Participants at one centre agreed to a substudy measuring a number of biomarkers and surrogates of CVD over 4 years, including anti-pneumococcal antibodies (immunoglobulin G and immunoglobulin M), C-reactive protein, carotid intima-media thickness, pulse wave velocity, insulin, fasting blood glucose, glycated haemoglobin, and hepatorenal index. RESULTS: Antipneumococcal immunoglobulin G and immunoglobulin M were both present and statistically significantly increased in the treated group compared to control at 4 years. However, there were no differences in any of the surrogate measures of CVD or metabolic markers at 4 years. CONCLUSIONS: While there were prolonged differences in anti-pneumococcal antibody titres following PPV vaccination, these did not appear to provide any cardioprotective effect, as measured by a range of markers. Final results using the fatal and nonfatal CVD events await the completion of national health record linkage next year. TRIAL REGISTRATION: ACTRN12615000536561.

H2O2-activated independently bidirectional regulation for a sensitive and accurate electrochemiluminescence ratiometric analysis.

Potential-resolved electrochemiluminescence (ECL) ratiometric analysis has become a research hotspot in bioassays by virtue of its good accuracy, versatility and specificity. Current ECL ratiometry mainly focuses on the competition for the co-reactant or quantitative analysis using a variable signal and a changeless signal; the disorganized change or small difference between the two signals may affect the accuracy and sensitivity of detection. In this study, we have developed a novel ECL ratiometric sensor based on the bidirectional regulation of two independent co-reaction systems by H2O2. H2O2 as a bidirectional moderator permits the ECL signals of the cathode and anode to independently change in opposite trends, which greatly enhances the organization and difference between the two signals. The ratio of the two signals is used to realize the quantitative analysis of myoglobin (MyO) with a good linear relationship between log(ECLcathode/ECLanode) and log CMyO in the range of 1.0 × 10-13 to 1.0 × 10-7 g mL-1. The detection limit is 4.0 × 10-14 g mL-1. Furthermore, it showed excellent performance in the determination of MyO in human serum samples. The proposed biosensor provides some developments for the sensitive and accurate detection of disease markers.

Dual-wavelength electrochemiluminescence ratiometry for hydrogen sulfide detection based on Cd2+-doped g-C3N4 nanosheets.

Herein, a novel and facile dual-wavelength ratiometric electrochemiluminescence-resonance energy transfer (ECL-RET) sensor for hydrogen sulfide (H2S) detection was constructed based on the interaction between S2- and Cd2+-doped g-C3N4 nanosheets (NSs). Cd2+-doped g-C3N4 NSs exhibited a strong ECL emission at 435 nm. In the presence of H2S, CdS was formed in situ on g-C3N4 NSs by the adsorption of S2- and Cd2+, generating another ECL emission at 515 nm. Furthermore, the overlapping of the absorption spectrum of the formed CdS and the ECL emission spectrum of g-C3N4 NSs led to a feasible RET, thus quenching the ECL intensity from g-C3N4 at 435 nm. Through an ECL decrease at 435 nm and an increase at 515 nm, a dual-wavelength ratiometric ECL-RET system for H2S was designed. The sensor exhibited a lower detection limit of 0.02 µM with a wide linear range of 0.05-100.0 µM. In addition, the applicability of the method was validated by plasma sample analysis with a linear range of 80.0-106.0%. We believe that such a proposal would provide new insight into advanced dual-wavelength ECL ratiometric assays.

The associations of serum valine with mild cognitive impairment and Alzheimer's disease.

BACKGROUND: The introduction of metabolomics makes it possible to study the characteristic changes of peripheral metabolism in Alzheimer's disease (AD). Recent studies have found that the levels of valine are related to mild cognitive impairment (MCI) and AD. AIMS: This study aimed to further clarify the characteristics of valine levels in MCI and AD. METHODS: A total of 786 participants from the Alzheimer's Disease Neuroimaging Initiative-1 (ADNI-1) cohort were selected to evaluate the relationships between serum valine and cerebrospinal fluid (CSF) biomarkers, brain structure (magnetic resonance imaging, MRI), cerebral glucose metabolism (18F-fluorodeoxyglucose-positron emission tomography, FDG-PET), and cognitive declines, through different cognitive subgroups. RESULTS: Serum valine was decreased in patients with AD compared with cognitive normal (CN) and stable MCI (sMCI), and in progressive MCI (pMCI) compared with CN. Serum valine was negatively correlated with CSF total tau (t-tau) and phosphorylated tau (p-tau) in pMCI. Serum valine significantly predicted conversion from MCI to AD. In addition, serum valine was related to the rate of change of cerebral glucose metabolism during the follow-up period in pMCI. CONCLUSIONS: Serum valine may be a peripheral biomarker of pMCI and AD, and its level predicts the progression of MCI to AD. Our study may help to reveal the metabolic changes during AD disease trajectory and its relationship to clinical phenotype.

Fabrication of Magnetic Al-Based Fe3O4@MIL-53 Metal Organic Framework for Capture of Multi-Pollutants Residue in Milk Followed by HPLC-UV.

The efficient capture of multi-pollutant residues in food is vital for food safety monitoring. In this study, in-situ-fabricated magnetic MIL-53(Al) metal organic frameworks (MOFs), with good magnetic responsiveness, were synthesized and applied for the magnetic solid-phase extraction (MSPE) of chloramphenicol, bisphenol A, estradiol, and diethylstilbestrol. Terephthalic acid (H2BDC) organic ligands were pre-coupled on the surface of amino-Fe3O4 composites (H2BDC@Fe3O4). Fe3O4@MIL-53(Al) MOF was fabricated by in-situ hydrothermal polymerization of H2BDC, Al (NO3)3, and H2BDC@Fe3O4. This approach highly increased the stability of the material. The magnetic Fe3O4@MIL-53(Al) MOF-based MSPE was combined with high-performance liquid chromatography-photo diode array detection, to establish a novel sensitive method for analyzing multi-pollutant residues in milk. This method showed good linear correlations, in the range of 0.05-5.00 µg/mL, with good reproducibility. The limit of detection was 0.004-0.108 µg/mL. The presented method was verified using a milk sample, spiked with four pollutants, which enabled high-throughput detection and the accuracies of 88.17-107.58% confirmed its applicability, in real sample analysis.

The functional hierarchy of the task-positive networks indicates a core control system of top-down regulation in visual attention.

The cingulo-opercular network (CON), dorsal attention network (DAN), and ventral attention network (VAN) are prominently activated during attention tasks. The function of these task-positive networks and their interplay mechanisms in attention is one of the central issues in understanding how the human brain manipulates attention to better adapt to the external environment. This study aimed to clarify the CON, DAN, and VAN's functional hierarchy by assessing causal interactions. Functional magnetic resonance imaging (fMRI) data from human participants performing a visual-spatial attention task and correlating Granger causal influences with behavioral performance revealed that CON exerts behavior-enhancing influences upon DAN and VAN, indicating a higher level of CON in top-down attention control. By contrast, the VAN exerts a behavior-degrading influence on CON, indicating external disruption of the CON's control set.

Dendrobium huoshanense Polysaccharides Prevent Inflammatory Response of Ulcerative Colitis Rat through Inhibiting the NF-κB Signaling Pathway.

The polysaccharides of the Chinese herbal medicine Dendrobium huoshanense exhibit anti-inflammatory effects in multiple organs through regulating the immune responses. In the present study, we constructed ulcerative colitis (UC) model rats using dextran sulfate sodium to investigate the anti-inflammatory effects of D. huoshanense polysaccharides (DHP). After oral administration of DHP for two weeks, the indices of UC symptoms, including the ratio of colon weight to length, Disease Activity Index (DAI), and Colon Mucosal Damage Index (CMDI), all decreased significantly compared with the UC model group. The histological sections also revealed better cell orders in DHP treatments than in the UC model rats. Moreover, in treatment with high dose of DHP (200 mg/kg), the treatment efficacy arrived the similar levels to those in the treatment with 300 mg/kg sulfasalazine, which is a typical medicine to treat UC. These results indicated that DHP has a high efficacy to treat UC in model rats. Furthermore, serum levels of interleukin-1ß, tumor necrosis factor-α, interleukin-17, and transforming growth factor-ß were assessed using the enzyme linked immunosorbent assay (ELISA) method, and the levels of nuclear factor-κB in colon tissue sections were determined using the immunohistochemical method. The results showed that all these indices decreased significantly after administration of DHP in UC model rats, which might be the mechanisms underlying the DHP-suppressed UC inflammation. Overall, this study indicated that DHP might be directly used to treat UC and is a promising source to develop novel drugs against UC.

Identification of Prognostic Related Hub Genes in Clear-Cell Renal Cell Carcinoma via Bioinformatical Analysis.

Objective To identify new genes that correlate with prognosis of clear-cell renal cell carcinoma (ccRCC) via bioinformatics analysis. Methods The gene expression profiles of 62 ccRCC and 54 normal kidney tissues were available from the Gene Expression Omnibus database: GSE12606, GSE36895 and GSE66272. The differentially expressed genes were screened with GEO2R and J Venn online tools. Functional annotation including Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) was applied to identify the possible function of the hub genes involved in prognosis of ccRCC. In protein protein interaction network (PPI network), the STRING online tool was used to visualize the network of the differentially expressed genes, and the core gene was selected by MCODE App in Cytoscape software. Finally, GEPIA Survival Plot was performed to assess genes associated with worse survival. Results We totally found 648 differentially expressed genes, including 222 up-regulated genes and 426 down-regulated genes. PPI network showed that in 28 up-regulated genes 7 (CCNE2, CDK1, CDC6, CCNB2, BUB1, TTK and PTTG1) enriched in cell cycle and 4 genes (CCNE2, CDK1, CCNB2 and RRM2) enriched in p53 signaling pathway. GEPIA Survival Plot assay revealed that ccRCC patients carrying CDK1, CCNB2, RRM2, BUB1, and PTTG1 had a worse survival. GEPIA Box Plot showed that BUB1, CCNB2, PTTG1, and RRM2 were over expressed in the ccRCC tissues in contrast to the normal tissues (P<0.05). Conclusion ccRCC patients with the four up-regulated differentially expressed genes including BUB1,CCNB2,PTTG1, and RRM2might manifest a poor prognosis.

A low-field nuclear magnetic resonance DNA-hydrogel nanoprobe for bisphenol A determination in drinking water.

A low-field nuclear magnetic resonance (LF-NMR) DNA-hydrogel (LNDH) nanoprobe was designed for bisphenol A (BPA) determination. It consists of Fe3O4 superparamagnetic iron oxide nanoparticles (SPIONs) and a DNA-hydrogel technology. Fe3O4 SPIONs were encapsulated in the DNA-hydrogel to form an aggregated state. After adding BPA, the gel system transformed into a sol gel due to the target-aptamer specific binding. The coated gathered particles dispersed and thus, the relaxation time T2 declined. The LNDH nanoprobe was developed to realize a simple, sensitive, and effective BPA determination method without repeated magnetic separation steps. Under the optimal experimental conditions, the determination range of the LNDH biosensor was 10-2~102 ng mL-1 and the limit of determination was 0.07 ng mL-1. The LNDH nanoprobe was applied to two kinds of water samples (tap water and bottled water). The recovery ranged from 87.85 to approximately 97.87%. This strategy offered a new method to detect BPA by LF-NMR. It is also expected to be applicable in related fields of food safety determination, environmental monitoring, and clinical diagnosis. Graphical abstract Schematic presentation of LNDH biosensor. Acrydite-modified ssDNA was copolymerized with acrylamide to form linear conjugates PS-A/B, adding aptamer and SPIONs to form DNA-hydrogel. When aptamer captured the target, the hydrogel was destroyed to disperse the coated SPIONs. T2 relaxation time declined.

[Regulatory effect of Jinkui Shenqi Pills on the gene expression of the Nrf2 signaling pathway in cyclophosphamide-induced testis injury in mice].

OBJECTIVE: To investigate the protective effect of Jinkui Shenqi Pills (JSP) against cyclophosphamide-induced testis injury (TI) and its anti-oxidation mechanism in mice. METHODS: Thirty male mice were equally divided into a blank control, a TI model control and a JSP treatment group. The mice in the JSP treatment group were treated intragastrically with JSP and the blank controls with normal saline at 1.2 g/kg qd for 7 days, and then the animals in both the TI model control and JSP treatment groups were injected intraperitoneally with cyclophosphamide at 50 mg/kg, once a week, for 35 days, to induce testis injury. After modeling, all the mice were weighed and sacrificed, followed by detection of the serum T content, measurement of the testis weight, examination of semen parameters in the caudad epididymis, and determination of the levels of super oxide dismutase (SOD) and malondialdehyde (MDA) in the testis tissue and the expressions of relevant genes by qRT-PCR. RESULTS: The mice of the TI model control group, compared with the blank controls, showed significant decreases in the body weight (ï¼»34.63 ± 1.92ï¼½ vs ï¼»48.32 ± 1.64ï¼½ g, P<0.05), testis weight (ï¼»80.00 ± 3.90ï¼½ vs ï¼»140.00 ± 6.10ï¼½ mg, P<0.05), testicular organ coefficient (ï¼»0.22 ± 0.01ï¼½ vs ï¼»0.31 ±0.03ï¼½%, P<0.05), sperm motility (ï¼»48.66 ± 8.08ï¼½% vs ï¼»89.33 ± 4.04ï¼½%, P<0.05), sperm concentration (ï¼»28.42 ± 5.26ï¼½ vs ï¼»77.67 ± 8.73ï¼½ ×106/ml, P<0.05), and levels of serum T (ï¼»8.75 ± 0.96ï¼½ vs ï¼»21.75 ± 1.71ï¼½ pg/ml, P<0.05) and SOD (ï¼»140.82 ± 10.08ï¼½ vs ï¼»358.52 ± 40.41ï¼½ U/mg prot, P<0.05), but remarkable increases in the sperm deformity rate (ï¼»37.33 ± 2.08ï¼½ vs ï¼»15.33±1.53ï¼½%, P<0.05) and MDA level (ï¼»54.89±6.09ï¼½ vs ï¼»30.21±2.17ï¼½ nmol/ng prot, P<0.05). The mice of the JSP treatment group, in comparison with the TI model controls, exhibited markedly increased body weight (ï¼»39.80±2.89ï¼½ vs ï¼»34.63±1.92ï¼½g, P<0.05), testis weight (ï¼»130.00 ± 11.00ï¼½ vs ï¼»80.00 ± 3.90ï¼½ mg, P<0.05), testicular organ coefficient (ï¼»0.28 ± 0.01ï¼½ vs ï¼»0.22 ± 0.01ï¼½%, P<0.05), sperm motility (ï¼»76.00 ± 5.29ï¼½% vs ï¼»48.66 ± 8.08ï¼½%, P<0.05), sperm concentration (ï¼»56.08 ± 4.29ï¼½ vs ï¼»28.42 ± 5.26ï¼½ ×106/ml, P<0.05), and levels of serum T (ï¼»15.50 ± 1.29ï¼½ vs ï¼»8.75 ± 0.96ï¼½ pg/ml, P<0.05) and SOD (ï¼»206.59 ± 16.38ï¼½ vs ï¼»140.82 ± 10.08ï¼½ U/mg prot, P<0.05), but decreased sperm deformity rate (ï¼»25.01 ± 2.99ï¼½% vs ï¼»37.33 ± 2.08ï¼½%, P<0.05) and MDA level (ï¼»35.84 ± 3.61ï¼½ vs ï¼»54.89 ± 6.09ï¼½ nmol/ng prot, P<0.05). The mRNA expressions of NOQ-1, Nrf2 and HO-1 in the testis tissue were significantly lower and that of Caspase-3 remarkably higher in the TI model control than in the blank control group (P<0.05), while those of Nrf2 and HO-1 significantly higher and that of Caspase-3 markedly lower in the JSP treatment group than in the TI model controls (P<0.05). Histopathological images displayed reduced layers of spermatogenic cells in the seminiferous tubules, complete exfoliation of the spermatogenic cells in some of the tubules and decreased number of sperm cells in the TI model controls, which were all found normal in the JSP treatment group. CONCLUSIONS: Jinkui Shenqi Pills can effectively inhibit cyclophosphamide-induced testis injury, which may be related to its effect of regulating the gene expression of the Nrf2 signaling pathway and enhancing the activity of antioxidant enzymes.

An Endo-Selective Epoxide-Opening Cascade for the Fast Assembly of the Polycyclic Core Structure of Marine Ladder Polyethers.

The rapid synthesis of marine ladder polyethers from polyepoxide precursors (in analogy with the biosynthetic pathway hypothesized by Nakanishi) is hampered by the fact that the exo-selective epoxide-opening cyclization cascade that gives THF-type polyethers is preferred over the endo-selective cascade that gives the desired products. We found that perfluoro-tert-butanol (PFTB) cooperating with 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM]BF4 ) can promote endo-selective epoxide-opening cyclization reactions of trisubstituted epoxy alcohols. Starting from readily accessible homochiral polyepoxy alcohols with a methyl group at all the endo-cyclization sites, we were able to construct polyethers up to five consecutive fused 6-, 7-, and/or 8-membered rings in one step. Notably, molecules with the 7/7/6/6 and 7/7/6/7/6 polyether frameworks of hemibrevetoxin B and brevenal, respectively, could be synthesized in 40 % and 17 % chemical yields.

Ru(NH3)63+/Ru(NH3)62+-Mediated Redox Cycling: Toward Enhanced Triple Signal Amplification for Photoelectrochemical Immunoassay.

Herein we report an effective Ru(NH3)63+/Ru(NH3)62+-mediated photoelectrochemical-chemical-chemical (PECCC) redox cycling amplification (RCA) strategy toward enhanced triple signal amplification for advanced split-type PEC immunoassay application. Specifically, alkaline phosphatase (ALP) label was confined via a sandwich immunorecognition to convert 4-aminophenyl phosphate to the signal reporter 4-aminophenol (AP), which was then directed to interact with Ru(NH3)62+ as a redox mediator and tris (2-carboxyethyl) phosphine (TCEP) as reducing agent in the detection buffer. Upon illumination, the system was then operated upon the oxidation of Ru(NH3)62+ by the photogenerated holes on the Bi2S3/BiVO4 photoelectrode, starting the chain reaction in which the Ru(NH3)62+ was regenerated by Ru(NH3)63+-enabled oxidization of AP to p-quinoneimine, which was simultaneously recovered by TCEP. Exemplified by interleukin-6 (IL-6) as the analyte, the Ru(NH3)63+/Ru(NH3)62+-mediated, AP-involved PECCC RCA coupled with ALP enzymatic amplification could achieve triple signal amplification toward the ultrasensitive PEC IL-6 immunoassay. This protocol can be extended as a general basis for other numerous targets of interest. Besides, we believe this work could offer a new perspective for the further exploration of advanced RCA-based PEC bioanalysis.

Reduced graphene oxide-gold nanoparticles-catalase-based dual signal amplification strategy in a spatial-resolved ratiometric electrochemiluminescence immunoassay.

A novel spatial-resolved electrochemiluminescent (ECL) ratiometry for cardiac troponin I (cTnI) analysis was developed using resonance energy transfer (RET) and a coreactant consumption strategy for signal amplification. Specifically, the spatial-resolved dual-disk glassy carbon electrodes were modified with CdS nanowires (CdS NWs) and luminol-gold nanoparticles (L-Au NPs) as potential-resolved ECL emitters, respectively. After stepwise immobilization of anti-cTnI and bovine serum albumin on the dual-disk electrodes, the CdS NWs-based electrode, with varied concentrations of cTnI, was used to provide a working signal, whereas the L-Au NPs-based electrode, with a fixed amount of cTnI, was employed to provide the reference signal. To efficiently amplify the working signal on the CdS NWs-based electrode, an anti-cTnI-reduced graphene oxide-gold nanoparticles-catalase probe (anti-cTnI-rGO-Au NPs-CAT) was loaded onto the electrode to form a sandwich immunocomplex. The RET from CdS NWs to Au NPs and the coreactant (i.e. H2O2) consumption by the CAT generate a significant ECL decrease on the CdS NWs-based electrode in the presence of cTnI. This novel and sensitive ratiometric detection mode for cTnI was achieved using the ratio values of the working signal of the CdS NWs-based electrode and the reference signal of the L-Au NPs-based electrode. The integration of RET and coreactant consumption strategy in the designed spatial-resolved ratiometric platform endows the immunosensor with a wide linear range of 5.0 × 10-13 - 1.0 × 10-7 g mL-1 and a low detection limit of 0.10 pg mL-1 for cTnI. Furthermore, the method exhibits high accuracy and sensitivity for cTnI determination in human serum samples.

Fabrication of silver nanoclusters with enhanced fluorescence triggered by ethanol solvent: a selective fluorescent probe for Cr3+ detection.

We present a facile method for the preparation of red-emitting and water-soluble silver nanoclusters (Ag NCs) using dihydrolipoic acid and sodium borohydride as the template and reducing agent. Ethanol solvent is demonstrated to endow Ag NCs with dramatically enhanced fluorescence; therefore, the Ag NCs are synthesized in ethanol/water solution (e/w-Ag NCs) instead of aqueous solution. Specific trivalent chromium (Cr3+) recognition capability of the e/w-Ag NCs can thus be obtained on the basis of its fluorescence quenching. The mechanisms for fluorescence enhancement and quenching of the e/w-Ag NCs triggered by ethanol and Cr3+, respectively, are investigated in detail. Next, a fluorescence method for detection of Cr3+ is established and its analytical performance is evaluated: the detection limit for Cr3+ is 0.71 µM and the linear range is from 2 to 40 µM. The fluorescent probe exhibits sufficient sensitivity and good selectivity toward Cr3+, illustrating that it has great promise for practical application in Cr3+ detection.

Evaluating recruitment strategies for AUSPICE, a large Australian community-based randomised controlled trial.

OBJECTIVES: To examine the effectiveness of different strategies for recruiting participants for a large Australian randomised controlled trial (RCT), the Australian Study for the Prevention through Immunisation of Cardiovascular Events (AUSPICE). DESIGN, SETTING, PARTICIPANTS: Men and women aged 55-60 years with at least two cardiovascular risk factors (hypertension, hypercholesterolaemia, overweight/obesity) were recruited for a multicentre placebo-controlled RCT assessing the effectiveness of 23-valent pneumococcal polysaccharide vaccine (23vPPV) for preventing cardiovascular events. METHODS: Invitations were mailed by the Australian Department of Human Services to people in the Medicare database aged 55-60 years; reminders were sent 2 weeks later. Invitees could respond in hard copy or electronically. Direct recruitment was supplemented by asking invitees to extend the invitation to friends and family (snowball sampling) and by Facebook advertising. MAIN OUTCOME: Proportions of invitees completing screening questionnaire and recruited for participation in the RCT. RESULTS: 21 526 of 154 992 invited people (14%) responded by completing the screening questionnaire, of whom 4725 people were eligible and recruited for the study. Despite the minimal study burden (one questionnaire, one clinic visit), the overall participation rate was 3%, or an estimated 10% of eligible persons. Only 16% of eventual participants had responded within 2 weeks of the initial invitation letter (early responders); early and late responders did not differ in their demographic or medical characteristics. Socio-economic disadvantage did not markedly influence response rates. Facebook advertising and snowball sampling did not increase recruitment. CONCLUSIONS: Trial participation rates are low, and multiple concurrent methods are needed to maximise recruitment. Social media strategies may not be successful in older age groups. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry, ACTRN12615000536561.