Silver Decorated and Graphene Wrapped Polypyrrole@Ni(OH)2 Quaternary Nanocomposite for High Performance Energy Storage Devices.

In this work, silver (Ag) anchored over graphene (GN) wrapped polypyrrole (PPy)@ nickel hydroxide (Ni(OH)2) nanocomposites were synthesized through a combination of oxidative polymerization and hydrothermal processes. The synthesized Ag/GN@PPy-Ni(OH)2 nanocomposites were characterized for their morphological characteristics by field emission scanning electron microscopy (FESEM), while the structural investigations were done by X-ray diffraction and X-ray photoelectron spectroscopy (XPS). The FESEM studies showed Ni(OH)2 flakes and silver particles attached over the surface of PPy globules, along with the presence of GN sheets and spherical silver particles. The structural analysis also showed the presence of constituents, i.e., Ag, Ni(OH)2, PPy, GN, and their interaction, therefore vouching that the synthesis protocol is efficacious. The electrochemical (EC) investigations were done in potassium hydroxide (1 M KOH) using a three electrode setup. The quaternary Ag/GN@PPy-Ni(OH)2 nanocomposite electrode showed the highest specific capacity of 237.25 C g-1. The highest electrochemical performance of the quaternary nanocomposite is associated with the synergistic/additional effect of PPy, Ni(OH)2, GN, and Ag. The assembled supercapattery with Ag/GN@PPy-Ni(OH)2 as a positive and activated carbon (AC) as a negative electrode displayed eminent energy density of 43.26 Wh kg-1 with the associated power density of 750.00 W kg-1 at a current density of 1.0 A g-1. The cyclic stability of the supercapattery (Ag/GN@PPy-Ni(OH)2//AC), comprising a battery-type electrode, displayed a high cyclic stability of 108.37% after 5500 cycles.

Tailored construction of one-dimensional TiO2/Au nanofibers: Validation of an analytical assay for detection of diphenylamine in food samples.

We report a one-dimensional titanium dioxide encapsulated with gold heterojunction nanofibers (TiO2/Au NFs) as robust electrocatalysts for electrochemical detection of diphenylamine (DPA). A TiO2/Au NFs were successfully synthesized by a coaxial electrospinning method. The formation of TiO2/Au NFs was confirmed by various analytical and spectroscopic approaches. The fabricated TiO2/Au NFs modified screen-printed carbon electrodes (SPCE) exhibit a well-enhanced detection activity towards DPA sensing as compared to other electrodes. Under the experimental conditions, the proposed electrode leading to the sensing range from 0.05 to 60 µM with a detection limit of 0.009 µM was obtained for the DPA detection. Moreover, the TiO2/Au NFs/SPCE showed good selectivity towards the electrochemical oxidation of DPA. Interestingly, the TiO2/Au NFs modified electrode was then applied to detect the effect of DPA on spiked content in the food samples.

Rational Confinement of Yttrium Vanadate within Three-Dimensional Graphene Aerogel: Electrochemical Analysis of Monoamine Neurotransmitter (Dopamine).

Real-time monitoring of neurotransmitter levels is of tremendous technological demand, which requires more sensitive and selective sensors over a dynamic concentration range. As a use case, we report yttrium vanadate within three-dimensional graphene aerogel (YVO/GA) as a novel electrocatalyst for detecting dopamine (DA). This synergy effect endows YVO/GA nanocomposite with good electrochemical behaviors for DA detection compared to other electrodes. Benefiting from tailorable properties, it provides a large specific surface area, rapid electron transfer, more active sites, good catalytic activity, synergic effect, and high conductivity. The essential analytical parameters were estimated from the calibration plot, such as a limit of detection (1.5 nM) and sensitivity (7.1 µA µM-1 cm-2) with the YVO/GA sensor probe electrochemical approach. The calibration curve was fitted with the correlation coefficient of 0.994 in the DA concentration range from 0.009 to 83 µM, which is denoted as the linear working range. We further demonstrate the proposed YVO/GA sensor's applicability to detect DA in human serum sample with an acceptable recovery range. Our results imply that the developed sensor could be applied to the early analysis of dementia, psychiatric, and neurodegenerative disorders.

Construction of strontium phosphate/graphitic-carbon nitride: A flexible and disposable strip for acetaminophen detection.

A facile technique has been used to synthesize the strontium phosphate interlinked with graphitic carbon nitride nanosheets (SrP/g-CN NSs) nanocomposite for highly selective detection of acetaminophen (AP). The formation of SrP/g-CN NSs nanocomposite is evidenced by several spectroscopic and analytical methods. It was demonstrated that the SrP/g-CN NSs modified screen-printed carbon electrode (SPCE) exhibits excellent catalytic performance with low peak potential towards AP detection than those of pristine SrP-, g-CN NSs-, and bare- SPCEs. The outstanding electrochemical performance can be attributed to the robust synergistic effect between SrP and g-CN NSs. Likewise, g-CN NSs possess a porous multilayer network, which provides a large surface area, fast charge transferability, electrical conductivity, and numerous active sites. Under the optimal conditions, the fabricated sensor could detect AP with a linear relationship range from 0.01 to 370 µM, and the detection limit is calculated to be as low as 2.0 nM. The proposed sensor is successfully used to determine AP in water samples with satisfactory results.

Cobalt Oxide Nanograins and Silver Nanoparticles Decorated Fibrous Polyaniline Nanocomposite as Battery-Type Electrode for High Performance Supercapattery.

In this study, silver (Ag) and cobalt oxide (Co3O4) decorated polyaniline (PANI) fibers were prepared by the combination of in-situ aniline oxidative polymerization and the hydrothermal methodology. The morphology of the prepared Ag/Co3O4@PANI ternary nanocomposite was studied by scanning electron microscopy and transmission electron microscopy, while the structural studies were carried out by X-ray diffraction and X-ray photoelectron spectroscopy. The morphological characterization revealed fibrous shaped PANI, coated with Ag and Co3O4 nanograins, while the structural studies revealed high purity, good crystallinity, and slight interactions among the constituents of the Ag/Co3O4@PANI ternary nanocomposite. The electrochemical performance studies revealed the enhanced performance of the Ag/Co3O4@PANI nanocomposite due to the synergistic/additional effect of Ag, Co3O4 and PANI compared to pure PANI and Co3O4@PANI. The addition of the Ag and Co3O4 provided an extended site for faradaic reactions leading to the high specific capacity. The Ag/Co3O4@PANI ternary nanocomposite exhibited an excellent specific capacity of 262.62 C g-1 at a scan rate of 3 mV s-1. The maximum energy and power density were found to be 14.01 Wh kg-1 and 165.00 W kg-1, respectively. The cyclic stability of supercapattery (Ag/Co3O4@PANI//activated carbon) consisting of a battery type electrode demonstrated a gradual increase in specific capacity with a continuous charge-discharge cycle until ~1000 cycles, then remained stable until 2500 cycles and later started decreasing, thereby showing the cyclic stability of 121.03% of its initial value after 3500 cycles.

Identification and Validation of Potential miRNAs, as Biomarkers for Sepsis and Associated Lung Injury: A Network-Based Approach.

Sepsis is a dysregulated immune response disease affecting millions worldwide. Delayed diagnosis, poor prognosis, and disease heterogeneity make its treatment ineffective. miRNAs are imposingly involved in personalized medicine such as therapeutics, due to their high sensitivity and accuracy. Our study aimed to reveal the biomarkers that may be involved in the dysregulated immune response in sepsis and lung injury using a computational approach and in vivo validation studies. A sepsis miRNA Gene Expression Omnibus (GEO) dataset based on the former analysis of blood samples was used to identify differentially expressed miRNAs (DEMs) and associated hub genes. Sepsis-associated genes from the Comparative Toxicogenomics Database (CTD) that overlapped with identified DEM targets were utilized for network construction. In total, 317 genes were found to be regulated by 10 DEMs (three upregulated, namely miR-4634, miR-4638-5p, and miR-4769-5p, and seven downregulated, namely miR-4299, miR-451a, miR181a-2-3p, miR-16-5p, miR-5704, miR-144-3p, and miR-1290). Overall hub genes (HIP1, GJC1, MDM4, IL6R, and ERC1) and for miR-16-5p (SYNRG, TNRC6B, and LAMTOR3) were identified based on centrality measures (degree, betweenness, and closeness). In vivo validation of miRNAs in lung tissue showed significantly downregulated expression of miR-16-5p corroborating with our computational findings, whereas expression of miR-181a-2-3p and miR-451a were found to be upregulated in contrast to the computational approach. In conclusion, the differential expression pattern of miRNAs and hub genes reported in this study may help to unravel many unexplored regulatory pathways, leading to the identification of critical molecular targets for increased prognosis, diagnosis, and drug efficacy in sepsis and associated organ injuries.