•Thiosemicarbazone derivatives as corrosion inhibitors for AA2024-T3 alloy.•Evaluation of inhibition efficiency by electrochemical methods.•Predominantly anodic inhibition, through adsorbed inhibitor ...layers.•Corroboration of experimental studies and theoretical studies.
Three thiosemicarzone derivatives, namely (E)-2-(2-hydroxybenzylidene) hydrazinecarbothioamide(MHC), (E)-2-(2,4-dihydroxybenzylidene)hydrazinecarbothioamide (DHC) and (E)-2-(2,3,4-trihydroxybenzylidene)hydrazinecarbothioamide (THC) were synthesized and their corrosion inhibition action on 2024-T3 aluminum alloy was studied in 3.5% NaCl solution. The surface morphology and surface composition of the corroded alloy were examined using FESEM, 3D profilometry, EDX spectroscopy and X-ray photoelectron spectroscopy. The synthesized inhibitors were found to provide corrosion protection on AA2024-T3 by forming an adsorbed layer of the complex on the alloy surface. They exhibited inhibition efficiency in the order, MHC < DHC < THC. Quantum chemical calculations corroborated the experimental results.
This manuscript reports the synthesis of pyrene-based fluorescent probe (PA-1) containing α,β-unsaturated carbonyl moiety and its application towards the selective and sensitive detection of cysteine ...(Cys) over other bio-thiols. The probe, 3-(2-hydroxyphenyl)-1-pyrenyl-2-propenone (PA-1) was synthesized through Claisen-Schmidt condensation between acetyl pyrene and salicylaldehyde. The formed product was characterized by 1H NMR, 13C NMR and GC–MS techniques. The probe exhibited absorption maximum at 374nm and emission maximum at 467nm (λex=342nm). The emission intensity of PA-1 was greatly enhanced while adding 2.5nM Cys. This can be attributed to the nucleophilic attack of Cys to the α,β-unsaturated ketone resulting in switching off, intramolecular charge transfer (ICT) from pyrene moiety to the phenolic nucleus. This was confirmed by DFT measurements. The PA-1 exhibited an excellent selectivity towards the determination of 40nM cys in the presence of 250,000-fold higher concentration of common interferents. The emission intensity was linearly increased and the limit of detection was found to be 10pM/L (S/N=3). Interestingly, the response of the PA-1 towards Cys is less than 1min. The confocal laser scanning micrographs of HeLa cells confirmed the cell permeability of the PA-1 and its ability to selectively detect Cys in living cells. In addition, the proposed probe was successfully applied for the determination of Cys in blood serum samples.
•A pyrene based fluorescent sensor for selective and sensitive detection of cysteine was developed.•Cysteine was determined based on the enhancement of emission intensity of the probe.•Cysteine specially finds with the α,β-unsaturated carbonyl group via Michael addition process.•Limit of detection of 10−12M cysteine under biological pH condition was achieved.•The sensor was successfully applied for the selective detection of Cys in living HeLa cells.
Pyrene-based fluorescent chemosensor for selective and sensitive detection of Hg2+ ion with ON-OFF mechanism.
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•A very simple synthetic procedure was employed for preparing the pyrene ...based probe.•Highly sensitive and selective Hg2+ recognition by ON-OFF mechanism.•LOD was found to be as low as 0.35nM.•This sensor could be effectively employed for real sample analysis.•It can be used for selective imaging of Hg2+ in living cells.
A highly selective and sensitive determination of Hg2+ in water samples with bioimaging applications in living cells using a fluorogenic pyrene-amino mercapto thiadiazole (PYAMT) probe is described. The probe PYAMT exhibited three absorption peaks at 333, 348 and 394nm and emission maxima at 378, 388 and 397nm (λex=348nm). It showed significant fluorescent quenching (96%) with I/I0=0.051 upon the addition of 2.5μM Hg2+ ion in CH3CN(ACN):H2O (1:1, v/v; pH 7.2), whereas its fluorescence remained unaltered in the presence of other metal ions. The quenching phenomenon is attributed to the heavy atom effect of Hg2+ ion followed by electron transfer. The fluorescence intensity decreased linearly against a wide range from 100nM to 2.5μM Hg2+ (R2=0.9937) with a limit of detection as low as 0.35nM (S/N=3). The binding stoichiometry ratio of PYAMT-Hg2+ is proved to be 1:1 by fluorescence and DFT measurements. The sensor possesses high association constant with Hg2+ ion in the order of 9.08×105M−1 and it is also capable of reversibly detecting cysteine with OFF-ON mechanism. Finally, the proposed method is successfully applied to selectively detect Hg2+ ion in real water samples and bioimaging studies in live cells.
One pot hydrothermal route was adapted to synthesis pristine and Sn doped α-Fe2O3 nanospheres successfully. Sharp high intense diffraction peaks obtained from XRD confirmed crystalline nature of ...rhombohedral hematite. The secondary SnO2 face formation was due to increasing Sn dopant concentration. Raman spectra confirmed intrinsic phonon vibration modes Eg(1)+Eg(2)+Eu of hematite nanospheres. 2P3/2(1) → 2P1/2 transition by emission peak at 549 nm confirmed hematite phase formation. Metal oxygen vibration (FeO stretching) was confirmed by absorption band situated at 539 cm−1. The noticeable variation in band gap of pristine hematite nanospheres was due to tetravalent Sn4+ dopant concentration. The lowest band gap energy 1.90 eV was found for 10 wt% Sn4+ doped hematite. Highest photocurrent 2.34 mA/cm2 at 0.098 V V RHE was obtained for 10% Sn doped hematite nanospheres. The EIS exposed the charge transferring mechanism of synthesized pristine and Sn doped α-Fe2O3 nanospheres. M-S plot evidenced that the lower shift of flat band potential for 10 wt% Sn4+ doped hematite was as −0.35 V. CA study proved the good stability over 4 h of the best performed photoanodes. Sn4+ doping and its dopant concentration on pristine hematite had dominant effect on photocatalytic activity of hematite nanospheres.
•Lowest band gap energy 1.90 eV was found for 10 wt% Sn4+ doped hematite.•Highest photocurrent 2.34 mA/cm2 at 0.098 V V RHE.•Lower shift of flat band potential as −0.35 V was obtained.•Good stability over 4 h was found for 10 wt% Sn4+ doped hematite.
Corrosion control of metals is of technical, economical, environmental, and aesthetical importance. The use of inhibitors is one of the best options of protecting metals and alloys against corrosion. ...The environmental toxicity of organic corrosion inhibitors has prompted the search for green corrosion inhibitors as they are biodegradable, do not contain heavy metals or other toxic compounds. As in addition to being environmentally friendly and ecologically acceptable, plant products are inexpensive, readily available and renewable. Investigations of corrosion inhibiting abilities of tannins, alkaloids, organic,amino acids, and organic dyes of plant origin are of interest. In recent years, sol-gel coatings doped with inhibitors show real promise. Although substantial research has been devoted to corrosion inhibition by plant extracts, reports on the detailed mechanisms of the adsorption process and identification of the active ingredient are still scarce. Development of computational modeling backed by wet experimental results would help to fill this void and help understand the mechanism of inhibitor action, their adsorption patterns, the inhibitor-metal surface interface and aid the development of designer inhibitors with an understanding of the time required for the release of self-healing inhibitors. The present paper consciously restricts itself mainly to plant materials as green corrosion inhibitors.
Many Coronavirus disease 2019 (COVID-19) and post-COVID-19 patients experience muscle fatigues. Early detection of muscle fatigue and muscular paralysis helps in the diagnosis, prediction, and ...prevention of COVID-19 and post-COVID-19 patients. Nowadays, the biomedical and clinical domains widely used the electromyography (EMG) signal due to its ability to differentiate various neuromuscular diseases. In general, nerves or muscles and the spinal cord influence numerous neuromuscular disorders. The clinical examination plays a major role in early finding and diagnosis of these diseases; this research study focused on the prediction of muscular paralysis using EMG signals. Machine learning–based diagnosis of the diseases has been widely used due to its efficiency and the hybrid feature extraction (FE) methods with deep learning classifier are used for the muscular paralysis disease prediction. The discrete wavelet transform (DWT) method is applied to decompose the EMG signal and reduce feature degradation. The proposed hybrid FE method consists of Yule-Walker, Burg’s method, Renyi entropy, mean absolute value, min-max voltage FE, and other 17 conventional features for prediction of muscular paralysis disease. The hybrid FE method has the advantage of extract the relevant features from the signals and the Relief-F feature selection (FS) method is applied to select the optimal relevant feature for the deep learning classifier. The University of California, Irvine (UCI), EMG-Lower Limb Dataset is used to determine the performance of the proposed classifier. The evaluation shows that the proposed hybrid FE method achieved 88% of precision, while the existing neural network (NN) achieved 65% of precision and the support vector machine (SVM) achieved 35% of precision on whole EMG signal.
Omega-3 fatty acids (n-3 PUFAs) are essential for the functional maturation of the brain. Westernization of dietary habits in both developed and developing countries is accompanied by a progressive ...reduction in dietary intake of n-3 PUFAs. Low maternal intake of n-3 PUFAs has been linked to neurodevelopmental diseases in Humans. However, the n-3 PUFAs deficiency-mediated mechanisms affecting the development of the central nervous system are poorly understood. Active microglial engulfment of synapses regulates brain development. Impaired synaptic pruning is associated with several neurodevelopmental disorders. Here, we identify a molecular mechanism for detrimental effects of low maternal n-3 PUFA intake on hippocampal development in mice. Our results show that maternal dietary n-3 PUFA deficiency increases microglia-mediated phagocytosis of synaptic elements in the rodent developing hippocampus, partly through the activation of 12/15-lipoxygenase (LOX)/12-HETE signaling, altering neuronal morphology and affecting cognitive performance of the offspring. These findings provide a mechanistic insight into neurodevelopmental defects caused by maternal n-3 PUFAs dietary deficiency.
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•Sm2O3 rice like nanorods was prepared by ESM-assisted hydrothermal method.•Sensitivity, stability and selectivity parameters analyzed for Sm2O3/rGO sensor towards LPG at RT.•The ...sensing mechanism explained based on Chemiresistive model.
Flexible electrochemical sensors have gained huge attention over their significant properties and the probability of applying to any wearable electronic devices. LPG traces in definite concentrations leads to a fire accident, adverse health effects, and even causes death. The current study focuses on a flexible, room temperature LPG sensor based on Sm2O3/rGO hybrid nanocomposite with different loading factors (1, 3, and 5 wt%) coated on flexible polyethylene terephthalate (PET) substrate working electrodes. Eggshell membrane (ESM) template constituents are acts as a reducing agent during the hydrothermal synthesis of Sm2O3 nanorods. Flexible Sm2O3/rGO hybrid Chemiresistive gas sensor was tested for various gas sensing parameters. The decoration of Sm2O3 nanorods on 3 wt% rGO sheets exhibited good selectivity to liquefied petroleum gas (LPG) at room temperature gives a response of 116% at 700 ppm of LPG with a short response, recovery time and gained 99% response after bending with 94.5% stability of the sensor.
•Develop a machine learning model for subgrouping dyslexics as high as low dyslexic based on their severity levels using K-Means clustering.•Analyze and evaluate the quality of the subgroups using ...MANOVA.•Proposed reference ranges for fixation and saccade duration to identify the severity level of dyslexia.
Dyslexia is a neurological disorder that causes poor reading and comprehension skills. Dyslexics experience problems in understanding phonemes of languages hence they show less ability to relate letters to form words and sentences. Dyslexia is not directly related to vision but it has been observed that most dyslexics have a magnocellular deficit which causes abnormal eye movements. From the literature, it has been observed that atypical eye movement could be a strong indicator of dyslexia.
This research work identifies the severity levels of dyslexia from fixations and saccade eye movement events based on eye gaze points. Fixations and saccades are computed using a velocity threshold algorithm. Features related to fixations and saccades are used to divide dyslexics into high and low based on their severity levels. Unsupervised learning approach K-Means clustering is adopted to group the dyslexics into high and low groups. Cluster evaluation measures such as Silhouette analysis, Elbow Method, and Davies Bouldin Index are used to find the optimal value of K. The quality of the clusters is further reinforced by Multivariate analysis of variance (MANOVA) analysis. Data in the clusters are visualized to understand the data distribution and range of different features.
K-means clustering gave two clusters – high and low dyslexics. The Silhouette score was high and the Davies Bouldin Index was low showing that the clusters are of good quality. MANOVA analysis has given a p-value less than 0.01 which further reinforces the quality of clusters to be good. The data in clusters are visualized, analyzed, and compared to existing eye movement findings on dyslexia in literature.
It has been observed that features such as fixation duration, number of fixations, saccade duration, and number of saccades act as key indicators to identify the severity levels of dyslexia. The characteristics of data in the clusters generated using these features match with the characteristics of existing eye movement findings, hence the data value ranges can be used to identify the severity levels of dyslexia.
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