Search

This study presents a comprehensive investigation into the synthesis, characterization, and application of an exceptionally sensitive electrochemical sensor designed for the ultrasensitive detection of 2,4-dinitrotoluene (DNT), a notorious explosive compound. The sensor employs bimetallic nickel-cobalt oxide (NiCo2O4) nanoparticles, synthesized through a facile hydrothermal method. Extensive analytical techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), and x-ray photoelectron spectroscopy (XPS), were employed to validate the crystallinity and purity of the NiCo2O4 nanoparticles. These nanoparticles, possessing remarkable properties, form the core of our electrochemical sensor, enabling it to offer heightened sensitivity and selectivity even under ambient conditions. Most notably, this sensor boasts an impressively low limit of detection (LOD) of 18 nM, coupled with a broad linear detection range (LDR) spanning from 10 nM to 100 nM. The sensor exhibits robust sensitivity, excellent selectivity, and an outstandingly low detection threshold, collectively demonstrating its potential for precise and accurate detection of DNT. This research underscores the significant potential of bimetallic oxide nanoparticles, specifically NiCo2O4, in the precise quantification of nitro-aromatic analytes. This study opens up promising avenues for assessing hazardous compounds in complex environmental matrices, thereby contributing to the advancement of electrochemical sensing. Additionally, this novel sensing platform holds substantial promise for enhancing security measures and environmental monitoring through its improved sensitivity and selectivity in the detection of explosives.

The escalating discharge of noxious gases resulting from unmitigated anthropogenic activities has emerged as a pivotal concern, presenting imminent threats to global ecosystems. In response to this pressing challenge, the development of cutting-edge materials within gas sensor systems emerges as a promising avenue for the precise detection of hazardous gaseous pollutants. This investigation delves into the synthesis and characterization of a novel composite material: reduced graphene oxide (rGO) modified with ruthenium Octaethyl porphyrin (Ru OEP), with a primary focus on its chemiresistive sensing properties. The meticulously deposited rGO-modified Ru OEP material onto gold microelectrodes, featuring a 3 µm gap on a silicon Si/SiO2 substrate, resulted in an intricate two-terminal chemiresistive sensor device. Comprehensive structural, spectroscopic, and morphological analyses were conducted to elucidate the intricacies of the composite material. The electrical characterization, evaluated through I-V measurements, provided nuanced insights into the device's resistance properties. Notably, the chemiresistive sensor demonstrated exceptional responsiveness to Carbon monoxide (CO) gas, exhibiting an impressively low limit of detection (LOD) at 2.5 ppm. The fabricated sensor showcased rapid response and recovery times, registering at 43 s and 65 s, respectively, underscoring its efficiency in real-time applications. Furthermore, the sensor maintained linearity and stability across a broad spectrum of conditions, ensuring prolonged reliability and consistent performance. This research underscores the potential of advanced materials, specifically the rGO-modified Ru OEP composite, in crafting highly effective gas sensors to address urgent environmental and safety concerns. The presented findings contribute invaluable insights to the burgeoning field of gas sensor technology, paving the way for innovative solutions to mitigate the adverse impacts of anthropogenic activities on our delicate ecosystems.

Significant advances in the field of energy storage have enabled scientists to explore highly stable electro-active electrodes for high-performance supercapacitors. The present investigation describes the synthesis of well-ordered NiMoO4 nanowalls at 140 °C using hydrothermal synthesis, which was then grown directly on Ni foam with different reaction times. The resulting NiMoO4 nanowalls were utilized as electro-active electrodes for electrochemical supercapacitor applications. The reaction time was found to be a critical factor in achieving the ordered NiMoO4 nanowalls on the Ni foam, and at a reaction time of 12 h, the nanosheets self-organized into a nanowall-like morphology over the Ni foam. Pure NiMoO4 crystal phases with less surface imperfections were produced by the 12-hour reaction time, as demonstrated by the compositional, structural, and crystalline characteristics. As an electro-active electrode, the NiMoO4 electrode with a 12-hour reaction time showed the highest specific capacitance of 357.6 Fg−1 at 0.01 Vs−1 compared to NiMoO4 electrodes with reaction times of 6h (53.06 Fg-1 at 0.01 Vs−1) and 20h (55.4 Fg-1 at 0.01 Vs−1). The NiMoO4 electrode also demonstrated exceptional stability in an alkaline electrolyte, exhibiting less deterioration in multicycles CV after 100 repeated cycles. The excellent electrochemical properties of the NiMoO4 electrode are attributed to its unique ordered nanowall structure, which improves surface area and electrical conduction, accelerating fast redox reactions. These properties make it a promising material for use in pseudocapacitors, with implications for high-performance energy storage solutions in industrial sectors.

A sensor can be called ideal or perfect if it is enriched with certain characteristics viz., superior detections range, high sensitivity, selectivity, resolution, reproducibility, repeatability, and response time with good flow. Recently, biosensors made of nanoparticles (NPs) have gained very high popularity due to their excellent applications in nearly all the fields of science and technology. The use of NPs in the biosensor is usually done to fill the gap between the converter and the bioreceptor, which is at the nanoscale. Simultaneously the uses of NPs and electrochemical techniques have led to the emergence of biosensors with high sensitivity and decomposition power. This review summarizes the development of biosensors made of NPssuch as noble metal NPs and metal oxide NPs, nanowires (NWs), nanorods (NRs), carbon nanotubes (CNTs), quantum dots (QDs), and dendrimers and their recent advancement in biosensing technology with the expansion of nanotechnology.

The opto-photocatalytic applications of Mn-doped NiO nanoparticles (NPs) are discussed. A facile synthesis of NiO doped with different Mn contents is performed and studied using experimental techniques. The structural properties and microstructural parameters of Mn:NiO NPs were examined by X-ray diffraction patterns. The average crystallite sizes of the pure NiO and 1.0-, 2.5-, 5.0-, 10-wt.% Mn-doped NiO NPs were found to be 25–19 nm by Williamson–Hall plots and 23–18 nm by the Debye–Scherer method. The crystallite size decreases with increasing doping concentration in the NiO host lattice. The optical bandgaps are found to be 3.53, 3.46, 3.39, 3.24, and 3.12 eV for pure NiO and 1.0-, 2.5-, 5.0-, and 10-wt.% Mn:NiO NPs, respectively, using the Kubelka–Munk function. X-ray photoelectron spectroscopy spectra of 2.5-wt.% Mn:NiO NPs were recorded for Mn, Ni, and O to determine the oxidation states. The photocatalytic performances of pure NiO and Mn:NiO NPs are examined. The 2.5-wt.% Mn:NPs exhibit the best photocatalytic performance owing to the greatest activation sites. The mechanism of the photocatalytic decolorization reaction is also investigated. The results demonstrate the high ability of Mn:NiO NPs as photocatalysts for methylene blue dye degradation, with 92% removal.

In this paper, highly dense and defined Co3O4 nanofibers were prepared by electrospinning method followed by controlled oxidation using polyvinylpyrrolidone (PVP) and CoCl2 as precursors. For the fabrication of effective electrochemical sensors and supercapacitors, the prepared Co3O4 nanofibers were used as electro-active electrodes. The prepared Co3O4 nanofibers were morphologically investigated by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) which confirmed the formation of highly dense and well-defined fibrous morphology. The X-ray diffraction (XRD) and elemental analysis demonstrated the typical crystalline cubic phase Co3O4 with appropriate stoichiometric element ratio. The supercapacitor with prepared Co3O4 nanofibers based electrode has an excellent cycle stability and a considerably higher specific capacitance of 419 C/g at a current density of 0.5 A/g. Interestingly, the fabricated supercapacitor device keeps 87% capacitance after 5000 charge/discharge cycles. For 2-butanone chemical sensing, the prepared Co3O4 nanofibers based electrode presents a reasonable sensitivity of 90.7 mAμM−1cm−2 and linear dynamics of 10–200 μM with good LOD of ∼5.8 μM and regression coefficient (R) = ∼0.97407. Thus, the prepared Co3O4 nanofibers with highly porous surface would pave the direction to the manufacturing of efficient energy storage and electrochemical sensing materials.

The soil contamination with heavy metal ions is one of the grave intricacies faced worldwide over the last few decades by the virtue of rapid industrialization, human negligence and greed. Heavy metal ions are quite toxic even at low concentration a swell as non-biodegradable in nature. Their bioaccumulation in the human body leads to several chronic and persistent diseases such as lung cancer, nervous system break down, respiratory problems and renal damage etc. In addition to this, the increased concentration of these metal ions in soil, beyond the permissible limits, makes the soil unfit for further agricultural use. Hence it is our necessity, to monitor the concentration of these metal ions in the soil and water bodies and adopt some better technologies to eradicate them fully. From the literature survey, it was observed that three main types of techniques viz. physical, chemical, and biological were employed to harness the heavy metal ions from metal-polluted soil samples. The main goal of these techniques was the complete removal of the metal ions or the transformation of them into less hazardous and toxic forms. Further the selection of the remediation technology depends upon different factors such as process feasibility/mechanism of the process applied, nature and type of contaminants, type and content of the soil, etc. In this review article, we have studied in detail all the three technologies viz. physical, chemical and biological with their sub-parts, mechanism, pictures, advantages and disadvantages.

The radiation-protection properties of the magnetic semiconducting quaternary compounds Cu2CoGeS4, Cu2CoGeSe4, and Cu2CoGeTe4 were examined in this study by using Phy-X/PSD software with the selected gamma energy (0.015–15 MeV). The radiation shielding coefficients such as mass and linear attenuation coefficients (MAC) and (LAC), half-value layer (HVL), and mean free path (MFP) of the present semiconductors were calculated. Also, the total electronic and atomic cross-sections (ECS and ACS), the effective atomic number (Zeff), the effective electron density (Neff), and the effective conductivity (Ceff) of these semiconductors were estimated to see how well they could protect against radiation. A comparative study occurred between the obtained results and the corresponding values of RS-253-G18, RS-360, RS-520 glasses, barite, chromite, and ferrite concrete. The results show that semiconducting samples with the best shielding performance outperform RS-253-G18, RS-360 glass, and RS-520 glass materials commonly used in nuclear applications. The Cu2CoGeTe4 sample had the highest MAC, LAC, and ACS, as well as the highest ECS and Zeff values. The other two semiconductor samples had the lowest MAC, ECS, and Zeff values. For photons, charged particles (electrons, protons, alpha particles), and C-ion, Phy-X/PSD allows the calculation of the Zeff quickly and precisely across the entire energy range. This study indicates that the semiconductor samples can be utilized as radiation attenuators for various nuclear fields.

The synthesis of pure and different concentrations of Cr-doped (1, 2.5, 5, 7, 10 wt%) lead iodide (PbI2) nanosheets was successfully achieved using a low-cost and simple microwave method. The prepared Cr-doped PbI2 nanostructures were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), FT-Raman, diffuse reflectance, dielectric, and gamma absorption analysis. The structural investigation confirmed the hexagonal phase of the proposed nanostructures without the impurity phase. Morphological studies proved that the undoped PbI2 nanosheet has a size of less than 100 nm, and the size of the prepared Cr-doped PbI2 samples was around 50-60 nm. FT-Raman and optical analysis investigated the doping effects on the pure PbI2 matrix through the slight shifting of characteristics peaks and the energy bandgaps’ variations. The optical bandgap values of pure PbI2 and Cr-doped PbI2 samples were estimated to be ranged from 2.0 eV to 2.2 eV. The obtained values of the dielectric constant were increased from 20 to 27 due to introducing the Cr- ions into the host PbI2 matrix. Together with Cr- dopants, the linear coefficient of Gamma absorption illustrates improvements. To conclude, due to the enhancement in structural morphology, optical, and radiation properties of the synthesized Cr-doped PbI2 nanostructures, those proposed nanosheets potentially are remarkable candidates for various applications including optoelectronics and radiation detectors.

Overall water splitting becomes an important strategy for the generation of hydrogen and oxygen in today's needs of green energy. Therefore, it is important to develop bifunctional electrocatalysts with cheap and high-efficient characteristics. However, traditional bifunctional catalysts usually exhibit high overpotential and poor stability during both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Herein, we synthesized several kinds of CoP nanorod catalysts through a facile hydrothermal method and subsequent thermal phosphorization process. The as-obtained CoP-1.5 product showed an overpotential of 58 mV for HER at 10 mA cm−2 and 284 mV for OER at 50 mV cm−2 in 1 M KOH. Moreover, the bifunctional catalyst, delivered a cell voltage of 1.66 V at 50 mA cm−2.

The synthesis, characterization, and photodetector application of pure and Ni doped CdS thin films prepared by the spray pyrolysis technique are presented in this paper. Various techniques were used to analyze the thin films that had been produced. The hexagonal phase of the produced thin films is confirmed by X-ray diffraction (XRD) and FT-Raman (FTR) measurements. Scanning electron microscopy (SEM) was used to investigate the morphology of the thin film surface, revealing the development of nanograins. The energy band gaps for all of the prepared thin films were calculated to be approximately 2.4 eV. When the films were stimulated at 450 nm wavelength, a strong photoluminescence emission was seen at ∼540 ± 6 nm. The dark/photo I-V electrical performance of the developed films was observed. The fabricated Au/CdS/Au and Au/Ni:CdS/Au photodetectors were studied for recombination behavior, dark and photo surface resistivity, and photosensitivity. Interestingly, the dark surface resistivity was found to be greater compared to the photo-resistivity. When the light intensity was increased to 1450 Lux, the photosensitivity improves from 10% to 35%. These findings indicate that the fabricated CdS/Ni:CdS films-based photodetectors are suitable for optoelectronic devices.

This review seeks to explore the literature pertaining to the applicability of nano-photocatalysts in fine chemical synthesis of organic compounds. The current methods of preparation of organic compounds in laboratories and industries are highly demanding on the non-renewable sources of energy. These conventional methods also generally require extreme conditions of temperature and pressure. Owing to deeper global awareness toward conservation of non-renewable sources of energy, there has been a shift of focus toward photocatalysis in the recent years. Photocatalysts are long known to catalyze various organic reactions such as oxidation, reduction, addition, cyclization and decomposition. The advent of nanotechnology made it possible to scale down these photocatalytic materials from bulk- to nano-scale and thereby further widen their scope and efficiency. Advances in material chemistry and nanotechnology have also made it possible to synthesize nanophotocatalysts of new genres, properties of which can be controlled and designed at molecular level. In this review, an attempt has been made to classify these diverse nanophotocatalysts into different groups, based on their composition and mechanism. Since the literature survey revealed that the chemoselectivity and efficiency of the nanophotocatalysts depend on their method of preparation, an overview of their common synthesis protocols is included. The review also highlights the various organic conversions for which these nanomaterials can be used under UV/visible irradiation. Nanophotocatalysts hold a great promise for environmentally-benign synthesis of highly useful organic compounds. We believe that this review can provide insights into research done in this field so far, which can pave way for further progress in this topic of far-fetched social significance. Keywords: Photocatalysis, Nano-photocatalysis, Organic synthesis, Green Chemistry, Photosensitization

Industrial wastes, for instance, tannery wastes are rich soups of resistant and bioremediation-potent bacteria. In the present work, Chromium (Cr) and tannic acid (TA) resistance bacterial strains were isolated from tannery effluent and identified as Bacillus subtilis (MCC 3275) and Bacillus safensis (MCC 3283) based on its 16S Ribosomal RNA homology. Hexavalent Cr is highly toxic and mutagenic due to its high mobility and reactivity. Whereas, TA is known to inhibit enzyme activity, substrate deprivation, and interaction with membranes and matrix-metal ions. The developed In vitro co-cultured microcosm of B. subtilis and B. safensis was able to remove Cr(VI) up to 95% and TA up to 23%. The bacteria cultures separately were able to degrade Cr(VI) to 88% by B. subtilis and 91% by B. safensis and TA up to 27%. Plackett Burman design (PBD) followed by Response surface methodology (RSM) was applied for the optimization of physio-chemical parameters. The optimized conditions for co-culture development were recorded as K2HPO4 = 0.2 g/L, MgSO4 = 0.2 g/L, NH4Cl = 0.5 g/L, glucose – 0.2 g/L, TA – 5%, Cr = 200 ppm, incubation period of 96 h, agitation speed of 110 rpm, pH = 5.0, temperature= 30 °C and inoculum size = 3%. Scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) revealed the thorough mechanism of cellular uptake followed by degradation of Cr(VI) and TA. The efficiency of co-culture for other heavy metals was observed as follows: Zn 65%, Pb 63%, Cd 65%, and Ni 65%. Bioremediation using bacteria is an economical and environmentally better alternative to conventional remediation methods. The isolated bacteria are useful in the effluent treatment of tannery or related industries and in metal recovery in mining processes.

A wound dressing with excellent hydrophilicity, high porosity, good mechanical property, and antimicrobial activities holds great potential for wound healing. Sericin, a natural protein from silkworm cocoon, is particularly attractive for the development of skin-repairing materials because it is biocompatible and biodegradable. Here, we reported a green strategy for in situ biomimetic synthesis of silver nanoparticles (AgNPs) within sericin/poly(vinyl alcohol) hydrogel. AgNPs were in situ synthesized by the redox property of tyrosine residues in sericin without additional chemicals, similar to a biomineralization process. AgNPs-sericin/poly(vinyl alcohol) dressing was demonstrated to bear desired high porosity, good wettability, hygroscopicity, and mechanical properties. The evaluation of cytocompatibility and immunotoxicity of the composite with NIH/3T3, HEK-293, and RAW264.7 cells further demonstrated its excellent biocompatibility. The composite also showed an effective antibacterial activity against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa, and could inhibit biofilm formation caused by Staphylococcus aureus and Pseudomonas aeruginosa. Finally, the animal experiment suggested that the composite dressing could facilitate re-epithelialization and collagen deposition to promote wound healing. Our work shows that the composite dressing has great potential as a competitive alternative for traditional wound dressings. Keywords: Biomimetic synthesis, Wound healing, Silk sericin, Silver nanoparticles, Antibacterial activity

Admissions records are essential in communicating key information regarding unwell patients and at handover of care. We designed, implemented and evaluated the impact of a standardised surgical clerking proforma on documentation and clinician acceptability in comparison to freehand clerking. A clerking proforma was implemented for all acute general surgical admissions. Documentation was assessed according to 32 criteria based on the Royal College of Surgeons of England guidelines, for admissions before (n = 72) and after (n = 96) implementation. Fisher's exact test and regression analysis were used to compare groups. Surgical team members were surveyed regarding attitudes towards the new proforma. Proforma uptake was 73%. After implementation, documentation increased in 28/32 criteria. This was statistically significant in 17 criteria, including past surgical history (p < 0.01), medication history (p = 0.03), ADLs (p = 0.02), systems review (p < 0.01), blood pressure (p < 0.01), blood results (p = 0.02) and advice given to the patient (p = 0.02). The proforma remained beneficial after regression analysis accounted for differences in time of day, seniority of the doctor and nights or weekends (coefficient = 0.12 [p < 0.01]). 89% of the surgical team felt the form improved quality of documentation and preferred its use to freehand clerking. 94% felt it was beneficial on the post-take ward-round. Audit quality control was also more reliable with the proforma (inter-observer agreement = 99.3% [κ = 0.997]) versus freehand clerking (97.1% [κ = 0.941]). Our study demonstrates that a standardised surgical clerking proformas improves the quantity and quality of documentation in comparison to freehand clerking, is preferred by health professionals and improves reliability of the audit quality control process.

Background: Statins effectively prevent atherosclerotic cardiovascular disease, but rates of statin discontinuation after adverse events are high., Objective: Describe the range and relative frequencies of adverse events potentially attributable to statins in lipid referral practice and assess statin rechallenge outcomes., Methods: Retrospective cohort study of 642 patients with statin-associated adverse events evaluated in a referral lipid clinic between January 1, 2004 and January 27, 2011., Results: Patients experiencing adverse events by organ system included 92% with musculoskeletal, 8% central nervous system, 10% liver, 8% gastrointestinal, 5% peripheral nervous system, 5% skin, and 3% other events. Overlap of organ system involvement occurred in 22.5%. At least 1 follow-up visit was made by 557 patients, among whom overall median follow-up was 25 months. Among patients treated with a statin in the clinic, 71% remained on a statin at the last follow-up visit. Patients with hepatic transaminase increases by history were numerically more likely than the overall group to resume or remain on statin treatment, whereas those reporting central nervous system or gastrointestinal symptoms trended lower for statin maintenance. Among patients who experienced an adverse event after statin rechallenge, the majority (64%) were being treated with intermittent, nondaily dosing at the time of the adverse event., Conclusion: Although musculoskeletal symptoms are reported by 90% of patients with statin intolerance, symptoms involving other organ systems may be more frequent than previously supposed. Understanding the range of symptoms, time course, and impact on daily activities informs counseling in patient-centered practice, but assessment of causation by statins remains challenging., (Published by Elsevier Inc.)