•Includes development of 1,8-naphthalimide based sensors during the last 5 years ranging from 2017 to 2021.•Describes the behaviour of 1,8-naphthalimide in different environments for detection of ...metal ions, anions and biomolecules.•Illustrates the role of position and nature of conjugation of 1,8-naphthalimide in various chemosensors.
Intensive development of optical (colorimetric/fluorescent) chemosensors is the landmark of successful research efforts made after the advent of supramolecular chemistry. Amongst different types of molecular scaffolds used, the literature of 1,8-naphthalimide is replete due its remarkable optical, photophysical and biological properties unequalled by other types of receptor units. This comprehensive compendium includes development of 1,8-naphthalimide based sensors during the last 5 years ranging from 2017 to 2021 that involve wide and real-world applications for sensing of metal ions, anions and biomolecules. Simultaneously, we hope that gaining insights into the discussed literature reports will assist the research fraternity working in the area of sensing and will facilitate to develop superlative chemosensors possessing improved practical applications in future.
Nanoparticles of Fe3O4 are prepared by simple co-precipitation method. The sample is characterized using an x-ray diffractometer, transmission electron microscope, and vibrating sample magnetometer. ...The x-ray diffraction pattern of the sample clearly shows that it is a single-phase magnetite. The transmission electron micrograph shows that the sample has a narrow distribution in particle size with average particle size of 9.9 nm. The SAED pattern only shows the diffraction planes correspond to magnetite and no other phase impurity is detected. The calculated thickness of the magnetic disordered shell due to the reduction in particle size is found to be 1.7 nm. The magnetization of the sample is measured as a function of temperature and applied magnetic field. The zero-field cooled and field cooled curves of the sample are measured in the presence of 250 Oe applied magnetic field and both the curves bifurcate at 170 K. The peak in the zero-field curve indicates that the sample has a blocking temperature of around 100 K. The magnetization as a function of applied magnetic field data at 200, 225, 250, 275 and 300 K are measured (up to ±20 kOe). These magnetization data are used for the fitting to analyze the magnetic behavior of Fe3O4 nanoparticles. . The magnetization of nanoparticles systems is influenced by several factors such as particle size distribution, disordered surface, magnetocrystalline anisotropy, magnetic moment distribution and magnetic interactions. The ignorance of such factors while analyzing the magnetization data leads to discrepancies in the results. The surface effects are sensitive to the reduction in particle size leading to the spin frustrations on the surface suggesting a magnetic disordered layer which affect the magnetic behavior of nanoparticles. This work presents the analysis of the magnetization data in an appropriate magnetization expression which takes into consideration the effect of magnetic moment distribution. This distribution in the magnetic moment is found to be significantly influenced the magnetization analysis and affected by the magnetic disordered surface which accounts for the presence of magnetic anisotropy and magnetic interactions on the particles surface. The results and observations are discussed in detail.
Objectives: 1. To describe perceived stress and changes in anxiety and coping among older adults between 2018 and 2020. 2. To examine the moderating roles of social support, exercise, alcohol use, ...and smoking on the relationship between perceived stress and anxiety. Methods: Longitudinal data collected from 3275 participants (M = 68.1 years) as part of the NZ Health, Work, and Retirement study’s 2018 and 2020 biennial surveys, were analyzed using hierarchical regression. Results: Older adults perceived COVID-19 as a low-level source of stress. Social support and alcohol use moderated the relationship between perceived mental stress and anxiety. At high-stress levels, only social support exerted a protective effect against the negative impact of stress on anxiety. Discussion: These findings support the general resilience of many older adults and highlight the effectiveness of coping strategies used by those groups who are more likely to be vulnerable to mental stress during a pandemic.
Swarm intelligence techniques have a vast range of real world applications.Some applications are in the domain of medical data mining where, main attention is on structure models for the ...classification and expectation of numerous diseases. These biomedical applications have grabbed the interest of numerous researchers because these are most serious and prevalent causes of death among the human whole world out of which breast cancer is the most serious issue. Mammography is the initial screening assessment of breast cancer. In this study, an enhanced version of Harris Hawks Optimization (HHO) approach has been developed for biomedical databases, known as DLHO. This approach has been introduced by integrating the merits of dimension learning-based hunting (DLH) search strategy with HHO. The main objective of this study is to alleviate the lack of crowd diversity, premature convergence of the HHO and the imbalance amid the exploration and exploitation. DLH search strategy utilizes a dissimilar method to paradigm a neighborhood for each search member in which the neighboring information can be shared amid search agents. This strategy helps in maintaining the diversity and the balance amid global and local search. To evaluate the DLHO lot of experiments have been taken such as (i) the performance of optimizers have analysed by using 29-CEC -2017 test suites, (ii) to demonstrate the effectiveness of the DLHO it has been tested on different biomedical databases out of which we have used two different databases for Breast i.e. MIAS and second database has been taken from the University of California at Irvine (UCI) Machine Learning Repository.Also to test the robustness of the proposed method its been tested on two other databases of such as Balloon and Heart taken from the UCI Machine Learning Repository. All the results are in the favour of the proposed technique.
This review encompasses and highlights recent developments of 1,10-phenanthroline (phen) ligands behaving as a customized moiety for assisting in recognition and sensing of cations and anions. ...Derivatization at various positions of phen (5,6-, 2,9-, 3,8- and 4,7-) results in ligands capable of acting as chemosensors for cations and anions. The perturbation induced in the energy levels of highly conjugated phen on substitution leads to detectable and measurable changes in the photophysical (UV-vis and fluorescence) properties of the system that serve as a tool for sensing cations and anions relevant to both environmental and biological systems. Hence phen yields a library of derivatized compounds which using the principles of coordination chemistry function as sensors for specific analytes (cations and anions). A database of various phenanthroline-derived receptors serving as chemosensors for various analytes in different solvents is presented and correlation of results can be used in the future for tuning photophysical properties, either by changing the substituted groups or their positions, so that the nearest desirable properties can be achieved for applications in biological and environmental sciences.
This review encompasses and highlights recent developments of 1,10-phenanthroline ligands behaving as a customized moiety used in recognition and sensing of cations and anions.
Despite the existing rapid and reliable analytical methods for determining biogenic amine in food matrices, recently special efforts have been devoted for development of portable and inexpensive ...devices for discrimination of biogenic amines (BAs) in food products to achieve onsite detection of food-spoilage. Thus, in this context, a field deployable cross-reactive sensor array and a field-portable array reader has been developed for determination of food quality. The sensor array consisting of metal complexes (C1 – C11) of single azophenol dye-based receptor generated a unique visible response on interaction with different amines (A1 – A7). Further, the colorimetric pattern and discrimination efficacy of the sensor array was evaluated using multivariate statistical techniques such as principal component analysis and linear discriminant analysis. Motivated by outstanding discriminatory power of sensor array, titration experiment was performed with BAs, and colorimetric response of array was linearly corelated to concentrations of BAs such as tryptamine and spermine with R2 values of 0.9596 and 0.967 respectively. Finally, for practical utility and the field analysis, a portable reader was developed and utilized for quantification of biogenic amines in meat and cottage cheese samples spiked with spermine and tryptamine up to the concentrations of 40 μM; therefore, apparently proving the potential applicability of the designed sensing method for food quality monitoring.
Simple colorimetric array and portable reader has been developed for food quality monitoring in complex environment using multivariate analysis. Display omitted
•Mammalian olfaction receptors inspired sensors array has been developed.•Successfully discriminated biogenic amines associated with food spoilage.•Multivariate techniques have been implemented for evaluating the discriminatory power of array.•Field deployable and economic plate reader has been fabricated and tested for real time analysis.
The schematic diagram shows the chemical transformations that have been used in the design of respective chemodosimeters for specific analyte. Display omitted
► Chemodosimeter provide analyte ...recognition with irreversible transduction and are relatively less affected by the environment and provide distinct advantage in terms of high selectivity. ► Metal ions primarily Hg2+, Cu2+, Fe3+, Ag+, Au3+, Pd2+ etc. and the anions viz. fluoride and cyanide and neutral molecules like thiols have been analysed using respective chemodosimeters. ► Provide simple approach for bioimaging of analytes in living cells and zebra fish. ► Chemical transformations viz. adduct formation, substitution, hydrolysis, oxidation and ring transformation etc. used in the design of chemodosimeters.
In this review, the applications of chemodosimeters in qualitative and quantitative estimation of various metal ions viz. Hg2+, Cu2+, Fe3+, Ag+, Pd(0)/Pd2+/Pd4+, Au3+/Au+ and anions viz. fluoride and cyanide and thiols have been discussed. Their use in bioimaging of analytes in living cells and zebra fish has also been presented. Various chemical transformations viz. adduct formation, substitution, hydrolysis, oxidation and ring transformation etc. have been used in the design of respective chemodosimeters for specific analyte. In total review contains 349 references.
A naked eye and fluorescence turn-on 1,8-naphtahlimide based chemosensor,
1,
possessing Schiff base linkage was utilized for the rapid detection of highly toxic triphosgene. The proposed sensor ...selectively detected triphosgene over various other competitive analytes including phosgene with the detection limit of 6.15 and 1.15 µM measured using UV-vis and fluorescence spectrophotometric techniques, respectively. Colorimetric changes observed in solution phase were processed by image analysis using smartphone leading to on-site and inexpensive determination of triphosgene. Further, solid phase sensing of triphosgene was carried out by
1
loaded PEG membranes and silica gel.
We report the effect of titanium doping on the structure, morphology, dielectric and electrical properties of zirconium ferrite Zr
1−x
Ti
x
Fe
2
O
4
(x = 0.0, 0.01, 0.03, 0.05) nanocrystalline ...ceramics prepared via sol–gel method. X-ray diffraction (XRD) technique confirmed the spinel structure of all samples and that the average crystallite size decreased with Ti doping. Scanning electron microscopy (SEM) confirmed the spherical-shaped morphology with an average grain size of 300 and 200 nm for x = 0 and 0.05, respectively. The Raman study revealed that Ti
4+
substitution slightly shifts the Raman modes towards the lower wavenumber. The dielectric studies analyzed using Impedance analyzer show the increase in dielectric parameters such as dielectric constant and dielectric loss with Ti concentration. The complex impedance analysis in the frequency range (10–10
6
Hz) is analyzed to understand the interactions from the grain and grain boundary phases. The dielectric feedback and impedance analysis studied the electrical properties in the 300–700 K temperature range and frequency range of 20–10
6
Hz. The AC conductivity increases with applied frequency and decreases with doping concentration. It is found that the Ti concentration increases the activation energy determined using the Arrhenius equation of AC conductivity and is a characteristic of polaron conduction. The Universal power law dependency of AC conductivity indicates charge transport made possible by hopping or tunneling. The temperature-dependent frequency exponent n’s observed minimal implies that the major transport mode is significant polaron tunneling.
The kinetics and chemical reaction mechanisms involved in the decomposition of eggshells are studied by experimental (thermogravimetric analysis and differential thermal analysis) as well as ...theoretical models. X-ray diffraction pattern of calcined eggshell at 1000 °C for 4 h exhibits monophasic CaO. The optical band gap of eggshell powder is observed 4.06 eV, which is less than commercial CaCO
3
(4.32 eV). The results showed that the activation energy for decomposition calculated through different methods is in good agreement with the reported value, i.e., in the range of 207–214 kJ mol
−1
. Based on Raman spectroscopy, eggshells exhibit better crystallinity and blue shift when compared to (conventional) CaCO
3
. The present work reveals that the eggshell can be used directly as a catalyst and as resources to synthesize the value-added materials. Eggshells and their byproducts could also be used as biomaterials and host for photoluminescence instead of commercial CaCO
3
.
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