Anion-directed structural tuning of two azomethine-derived Zn2+ complexes with optoelectronic recognition of Cu2+ in aqueous medium with anti-cancer activities: from micromolar to femtomolar sensitivity with DFT revelation.

Herein, two novel mononuclear transition metal Zn2+ complexes i.e. [Zn(HL)(N3)(OAc)] (NS-1) & [Zn(HL)2(ClO4)2] (NS-2) have been synthesised using a tridentate clickable Schiff base ligand, HL (2-methyl-2-((pyridin-2-ylmethyl)amino)propan-1-ol), and the polyatomic monoanions N3- and ClO4- for NS-1 and NS-2 respectively. Interestingly, NS-1 and NS-2 have been explored for the detection of Cu2+ with an LOD of 48.6 fM (response time ∼6 s) and 2.4 µM respectively through two mutually independent pathways that were studied using sophisticated methods like UV-Vis, cyclic voltammetry, ESI-MS etc. with theoretical DFT support. Herein, both chemosensors are equally responsive towards the detection of Cu2+ in aqueous as well as other targeted real field samples with appreciable recovery percentage (74.8-102%), demonstrating their practical applicability. Moreover, the detection of unbound Cu2+ in a human urine specimen was also analysed which may be helpful for the diagnosis of Cu2+-related disorders like Wilson's disease. Taking one step ahead, TLC strips have been employed for on-field detection of the targeted analytes by contact mode analysis. Additionally, the anti-cancer activity of these complexes has also been studied on breast cancer cells with the help of the MTT assay. It has been found that at a 0.5 mM dose, both NS-1 and NS-2 could kill 81.4% and 73.2% of cancer cells respectively. However, it has been found that NS-1 destroys normal cells together with cancer cells. Hence, NS-2 could be administered as a better anticancer drug for MDA-MB-231 cancer cells in comparison with NS-1. In a nutshell, the present work describes how anion-directed synthesis of two architecturally different metal complexes leads toward the detection of the same analyte via an independent chemodosimetric pathway along with their anti-cancer activities on breast cancer cells.

Compression-induced buckling of a semiflexible filament in two and three dimensions.

The ability of biomolecules to exert forces on their surroundings or resist compression from the environment is essential in a variety of biologically relevant contexts. For filaments in the low-temperature limit and under a constant compressive force, Euler buckling theory predicts a sudden transition from a compressed state to a bent state in these slender rods. In this paper, we use a mean-field theory to show that if a semiflexible chain is compressed at a finite temperature with a fixed end-to-end distance (permitting fluctuations in the compressive forces), it exhibits a continuous phase transition to a buckled state at a critical level of compression. We determine a quantitatively accurate prediction of the transverse position distribution function of the midpoint of the chain that indicates this transition. We find that the mean compressive forces are non-monotonic as the extension of the filament varies, consistent with the observation that strongly buckled filaments are less able to bear an external load. We also find that for the fixed extension (isometric) ensemble, the buckling transition does not coincide with the local minimum of the mean force (in contrast to Euler buckling). We also show that the theory is highly sensitive to fluctuations in length in two dimensions and the buckling transition can still be accurately recovered by accounting for those fluctuations. These predictions may be useful in understanding the behavior of filamentous biomolecules compressed by fluctuating forces, relevant in a variety of biological contexts.

Exploratory studies on azido-bridged complexes (Ni2+ and Mn2+) as dual colourimetric chemosensors for S2- and Ag+: combined experimental and theoretical outcomes with real field applications.

We report two isostructural dinuclear transition metal complexes [M2(HL)2(N3)4], where M = Ni2+ (BS-1), Mn2+ (BS-2), and HL is (2-methyl-2-((pyridin-2-ylmethyl)amino)propan-1-ol) and investigate them as molecular sensors towards hazardous entities. BS-1 shows high selectivity towards the S2- and Ag+ ions, easily observed by the naked eye colour change and its detection limit in aqueous solutions for the S2- ion was calculated as 0.55 µM with a binding constant of 3.28 × 105 M-1, while the limit for the Ag+ ion is 21.8 µM. Notably, BS-2 shows good selectivity towards the Ag+ ion with a detection limit of 10.84 µM. Spectroscopic and DFT studies shed light on the mechanistic course of interaction between the host and guest entities, suggesting a sulphide-mediated reduction of the azide mechanism. In a nutshell, these simple transition metal complexes were exploited for discriminately detecting hazardous analytes with real field applications in analytical science (via. "Dip-Stick" approach) as well as engineering science, which provides a significant contribution in the recent advancement of supramolecular chemistry.

Detoxification and eco-friendly recycling of brick kiln coal ash using Eisenia fetida: A clean approach through vermitechnology.

Brick kiln coal ashes (BKCAs) are one of the major toxic byproducts of the rapidly growing construction industry in developing countries. However, eco-friendly recycling avenues for BKCAs are yet to be explored. The major objectives of the present research were to evaluate the viability of vermitechnology in transforming BKCAs into valuable products, and to examine the metal detoxification potential of Eisenia fetida BKCA-based feedstocks. BKCAs were mixed in large scale with cow dung (CD) in 1:1 and 2:1 ratios, for vermicomposting and aerobic composting; performance was assessed in comparison with CD. Vermiconverted-BKCA was then used as organic fertilizer for rice grown in poorly fertile soil. Acidic nature of BKCA feedstocks was neutralized by 30-86% in the vermireactors. Total N and available P concentrations significantly increased in the vermireactors supplemented with considerable mineralization of total organic C. Exorbitantly high K and S contents were pacified to a normal range after vermicomposting. Greater improvement in microbial biomass, respiration, fungal and bacterial growth was observed under vermicomposting against aerobic composting. Consequently, urease and phosphatase activity increased by 1-4 folds in the BKCA based vermibeds. Bioavailability of toxic metals reduced by 41-74% in the vermicomposted BKCAs. High metal accumulation by the earthworms resulted in substantial reduction of pollution load in the finished product. The field experiment demonstrated that vermiconverted-BKCA could be utilized as potential organic fertilizer for rice production, soil fertility rejuvenation, and metal detoxification. Overall, the study reveals that E. fetida could be used as an efficient contender for sanitization of toxic BKCAs.

Environmental footprints of brick kiln bottom ashes: Geostatistical approach for assessment of metal toxicity.

Coal fired brick kiln factories generate significant of brick kiln bottom ash (BKBA) that contaminate soil and water environments of areas near the dumping sites through leaching of toxic metals (Pb, Cr, Cd, Zn, Mn, and Cu). However, characteristics and environmental effects of BKBAs are yet unknown. We collected BKBA samples from 32 strategic locations of two rapidly developing States (West Bengal and Assam) of India. Scanning electron microscope images indicated spherical and granular structures of BKBAs produced in West Bengal (WBKBA) and Assam (ABKBA) respectively; while energy dispersive spectroscopy and analytical assessments confirmed substantial occurrence of total organic C and nutrient elements (N, P, K, Ca, Mg, and S) in both the BKBAs. FTIR analysis revealed greater predominance of organic matter in ABKBAs than WBKBAs. Occurrence of toxic metals (Cd, Cr, Pb, Zn, Mn, and Cu) was higher in ABKBAs than in WBKBAs; while organic and residual fractions of metals were highly predominant in most of the BKBAs. Principal component analysis showed that metal contents and pH were the major distinguishing characteristics of the BKBAs generated in the two different environmental locations. Human health risk associated with BKBAs generated in Assam is of significant concern. Finally, geo-statistical tools enabled to predict the spatial distribution patterns of toxic metals contributed by the BKBAs in Assam and West Bengal respectively. Assessment of contamination index, geo-accumulation index, and ecological risk index revealed some BKBAs to be more toxic than others.

Quantitative analysis of Euclidean distance to complement qualitative analysis of facial expression during deception.

BACKGROUND: Accurate evaluation of an individuals' veracity is a fundamental aspect of social functioning that allows individuals to act in adaptive ways. The domain of deception detection ability is still young, and many components in this field are yet to be touched which demands more research in this field. AIMS: The present study aims at deciphering the structural composition of face during felt, posed, and deceived emotions in facial expression unique to Indian culture, using Facial Action Coding System (FACS). Quantitative analysis of Euclidean distance has been done to complement qualitative FACS analysis. METHODS: In this study, thirty female, young adults with age range of 23-27 years were chosen randomly for portraying their (felt, posed, and deceived) facial expression. All facial expressions were captured through instruction, and videos were converted into static images. The static images were coded on the basis of FACS to decipher the felt, posed, and deceived expressions. Quantitative analysis of the data has been done using MATLAB to meet the objectives of the study and to complement the qualitative analysis. RESULTS: Felt and posed emotions differ in terms of intensity of the expression and subjective experience. Posed emotional and deceived expressions differ in intent. Facial asymmetry is an important indicator for detecting deception.