Evaluating hydrogeochemical controls and noncarcinogenic health risk assessment of fluoride concentration in groundwater of Palacode and Pennagaram taluk, Dharmapuri district, Tamil Nadu, India.

This study focuses on assessing hydrochemical characteristics and non-carcinogenic health risks associated with fluoride contamination in groundwater within the Palacode and Pennagaram taluks of Dharmapuri district. The presence of fluoride in drinking water is a significant concern due to its potential health impacts on both adults and children. We collected a total of 158 groundwater samples during both the summer (SUM) and monsoon (MON) seasons in 2021 to evaluate the suitability of water for drinking purposes in this region. During the SUM season, groundwater exhibits alkaline characteristics with a pH range of 6.70 to 8.73 and a mean value of 7.43, while the MON season falls within the neutral pH range with values ranging from 6.60 to 7.60 and a mean of 7.00. Hydrogeochemical analysis reveals that fluoride concentrations during the SUM season range from 0.13 to 2.7 mg/L, with a mean of 0.82 mg/L, whereas the MON season exhibits concentrations ranging from 0.08 to 1.6 mg/L, with a mean of 0.5 mg/L. Spatial distribution analysis indicates a gradual increase in fluoride concentrations from the northeast to the central and southern parts of the study area during both seasons. Residents in these areas have been exposed to high fluoride levels for an extended period, leading to health issues related to fluorosis. Our hydrogeochemical analysis attributes fluoride dominance to the Cl--SO42- water type in both seasons. Furthermore, the relationship between fluoride and pH, HCO3-, Ca2+, and Na+ suggests the influence of geological factors in fluoride dissolution under alkaline conditions, while a reverse cation exchange process and increasing calcium concentration inhibit fluoride concentration. Saturation indices indicate that the unsaturated state of gypsum dissolution contributes to elevated fluoride levels in groundwater. Additionally, Gibbs plots highlight rock-water interactions as a significant factor influencing groundwater chemistry in the study area. Based on our hazard quotient (HQ) investigation, children are at a higher risk during both seasons compared to adults, with the central and northern regions showing alarming HQ values. These findings underscore the urgent need for enhanced groundwater quality monitoring and a comprehensive assessment of health risks, providing valuable insights for groundwater safety management in vulnerable areas of this region.

Integrated hydrogeophysical and GIS based demarcation of groundwater potential and vulnerability zones in a hard rock and sedimentary terrain of Southern India.

This research has identified the groundwater potential and vulnerability zones in Tiruchirappalli district of Tamil Nadu, India. The Schlumberger electrode array has been used to conduct vertical electrical sounding (VES) at 95 sites with a maximum electrode spacing of 150 m. The study area comprises of hard rock and sedimentary formations. Geographical Information System (GIS) has been used to integrate the geoelectrical data and to prepare spatial variation maps for various parameters. Finally, groundwater potential and vulnerability zones have been demarcated, and these outputs have been validated using water level and nitrate data, respectively. The Dar-Zarrouk parameters such as longitudinal conductance (S), transverse unit resistance (T), and aquifer anisotropy (λ) have been used along with the spatial variation of resistivity and aquifer thickness to find out groundwater potential areas with the support of GIS. The thickness of topsoil, weathered zone and fractured zone are not uniform in the research area. Top soil plus weathered zone acts as a water table (phreatic) aquifer, which extends up to 38 m from the surface. Fractured zone extends up to 45 m, which acts as a kind of confined/semi-confined aquifer. Open and bore wells have been constructed to tap groundwater from the unconfined (water table) and confined/semi-confined aquifers, respectively. High to very high groundwater potential areas are associated with low resistivity, high thickness, low longitudinal conductance, high transverse unit resistance and high aquifer anisotropy areas. Very high groundwater potential areas are mostly confined to flood plain (alluvium) deposits in the central portion of the study area. High potential areas are noticed in the northern part, whereas low potential areas are noticed in the southern part. The areas with high longitudinal conductance indicate low permeable zones with less possibility of external pollution. Since agriculture is an important activity in the study region, this work will be useful to provide water supply for irrigation as well as for domestic needs.

Dataset on the suitability of groundwater for drinking and irrigation purposes in the Sarabanga River region, Tamil Nadu, India.

The present datasets reveal that to assess the suitability of groundwater quality for drinking and irrigation uses in both Pre and Post Monsoon Season in Sarabanga River region, Tamilnadu, India based on various water quality indices. A total of 50 groundwater samples were collected in different location in a research area. Water Quality Index (WQI) is a number which indicates the suitability of water for drinking purpose. Sodium Absorption Ratio (SAR), Permeability Index (PI), Residual Sodium Carbonate (RSC), Percentage Sodium (%Na), Kelly Ratio (KR) and Magnesium Hazards (MH) are index value which elaborates the fitness of groundwater for agriculture uses. The WQI value for groundwater in both seasons reveals that 74.5 sq.km and 37.24 sq.km of the area were unfit for domestic purposes. Based on irrigation indices, almost all sample locations are suitable for irrigation purposes. The dataset demonstrates how water quality indices would be applied to policymakers to manage, handle and sustainably improve society at large.

A unified machine-learning protocol for asymmetric catalysis as a proof of concept demonstration using asymmetric hydrogenation.

Design of asymmetric catalysts generally involves time- and resource-intensive heuristic endeavors. In view of the steady increase in interest toward efficient catalytic asymmetric reactions and the rapid growth in the field of machine learning (ML) in recent years, we envisaged dovetailing these two important domains. We selected a set of quantum chemically derived molecular descriptors from five different asymmetric binaphthyl-derived catalyst families with the propensity to impact the enantioselectivity of asymmetric hydrogenation of alkenes and imines. The predictive power of the random forest (RF) built using the molecular parameters of a set of 368 substrate-catalyst combinations is found to be impressive, with a root-mean-square error (rmse) in the predicted enantiomeric excess (%ee) of about 8.4 ± 1.8 compared to the experimentally known values. The accuracy of RF is found to be superior to other ML methods such as convolutional neural network, decision tree, and eXtreme gradient boosting as well as stepwise linear regression. The proposed method is expected to provide a leap forward in the design of catalysts for asymmetric transformations.

Modulating the Global Response Regulator, LuxO of V. cholerae Quorum Sensing System Using a Pyrazine Dicarboxylic Acid Derivative (PDCApy): An Antivirulence Approach.

Vibrio cholerae is a Gram-negative pathogen which causes acute diarrhoeal disease, cholera by the expression of virulence genes through quorum sensing (QS) mechanism. The QS circuit of V. cholerae is controlled by the global quorum regulator, LuxO, which at low cell density (LCD) state produces major virulence factors such as, toxin co-regulated pilus (TCP) and cholera toxin (CT) to mediate infection. On the contrary, at the high cell density (HCD) state the virulent genes are downregulated and the vibrios are detached from the host intestinal epithelial cells, promoted by HapA protease. Hence, targeting the global regulator LuxO would be a promising approach to modulate the QS to curtail V. cholerae pathogenesis. In our earlier studies, LuxO targeted ligand, 2,3 pyrazine dicarboxylic acid (PDCA) and its derivatives having desired pharmacophore properties were chemically synthesized and were shown to have biofilm inhibition as well as synergistic activity with the conventionally used antibiotics. In the present study, the QS modulatory effect of the PDCA derivative with pyrrolidine moiety designated as PDCApy against the V. cholerae virulence gene expression was analyzed at various growth phases. The data significantly showed a several fold reduction in the expression of the genes, tcp and ct whereas the expression of hapR was upregulated at the LCD state. In addition, PDCApy reduced the adhesion and invasion of the vibrios onto the INT407 intestinal cell lines. Collectively, our data suggest that PDCApy could be a potential QS modulator (QSM) for the antivirulence therapeutic approach.

Antimicrobial and Antibiofilm Potential of Acyclic Amines and Diamines against Multi-Drug Resistant Staphylococcus aureus.

Multi-drug resistant Staphylococcus aureus (MDRSA) remains a great challenge despite a decade of research on antimicrobial compounds against their infections. In the present study, various acyclic amines and diamines were chemically synthesized and tested for their antimicrobial as well as antibiofilm activity against MDRSA. Among all the synthesized compounds, an acyclic diamine, (2,2'-((butane-1,4-diylbis(azanediyl)bis(methylene))diphenol) designated as ADM 3, showed better antimicrobial activity (minimum inhibitory concentration at 50 µg/mL) and antibiofilm activity (MBIC50 at 5 µg/mL). In addition, ADM 3 was capable of reducing the virulence factors expression (anti-virulence). Confocal laser scanning microscope analysis of the in vitro tested urinary catheters showed biofilm reduction as well as bacterial killing by ADM 3. On the whole, our data suggest that acyclic diamines, especially ADM 3 can be a potent lead for the further studies in alternative therapeutic approaches.

Inhibition of the Quorum Sensing System (ComDE Pathway) by Aromatic 1,3-di-m-tolylurea (DMTU): Cariostatic Effect with Fluoride in Wistar Rats.

Dental caries occurs as a result of dysbiosis among commensal and pathogenic bacteria leading to demineralization of enamel within a dental biofilm (plaque) as a consequence of lower pH in the oral cavity. In our previous study, we have reported 1,3-disubstituted ureas particularly, 1,3-di-m-tolylurea (DMTU) could inhibit the biofilm formation along with lower concentrations of fluoride (31.25 ppm) without affecting bacterial growth. In the present study, RT-qPCR analysis showed the target specific molecular mechanism of DMTU. In vivo treatment with DMTU, alone or in combination with fluoride, resulted in inhibition of caries (biofilm development of Streptococcus mutans) using a Wistar rat model for dental caries. The histopathological analysis reported the development of lesions on dentine in infected subjects whereas the dentines of treated rodents were found to be intact and healthy. Reduction in inflammatory markers in rodents' blood and liver samples was observed when treated with DMTU. Collectively, data speculate that DMTU is an effective anti-biofilm and anti-inflammatory agent, which may improve the cariostatic properties of fluoride.

Staphylococcus aureus Quorum Regulator SarA Targeted Compound, 2-[(Methylamino)methyl]phenol Inhibits Biofilm and Down-Regulates Virulence Genes.

Staphylococcus aureus is a widely acknowledged Gram-positive pathogen for forming biofilm and virulence gene expressions by quorum sensing (QS), a cell to cell communication process. The quorum regulator SarA of S. aureus up-regulates the expression of many virulence factors including biofilm formation to mediate pathogenesis and evasion of the host immune system in the late phases of growth. Thus, inhibiting the production or blocking SarA protein might influence the down-regulation of biofilm and virulence factors. In this context, here we have synthesized 2-[(Methylamino)methyl]phenol, which was specifically targeted toward the quorum regulator SarA through in silico approach in our previous study. The molecule has been evaluated in vitro to validate its antibiofilm activity against clinical S. aureus strains. In addition, antivirulence properties of the inhibitor were confirmed with the observation of a significant reduction in the expression of representative virulence genes like fnbA, hla and hld that are governed under S. aureus QS. Interestingly, the SarA targeted inhibitor showed negligible antimicrobial activity and markedly reduced the minimum inhibitory concentration of conventional antibiotics when used in combination making it a more attractive lead for further clinical tests.

Microbial Fouling in a Water Treatment Plant and Its Control Using Biocides.

　Water treatment plants (WTP) are vital in the food, pharmaceutical and chemical process industries. This investigation describes the dense microbial fouling by microbes and organic compounds in a WTP of a heavy water producing industrial unit. On-site observations showed severe algal and bacterial growth in the various units of the WTP which are open to the atmosphere and very dense fungal fouling in the closed vacuum degasser unit. Digital and microscopic images showed that the microbial fouling problem was primarily due to a fungus. Microbiological analysis showed a count of ~105 cfu mL-1 in various sections of the WTP. On the contrary, slime/biofilm scrapings had very high bacterial populations (>109 cfu cm-2). High organic carbon values in the system (5.0 to 19.5 ppm) had supported the growth of the fouling fungus in various sections of the WTP along with bacteria. Chlorination was found to be inadequate in controlling the biofouling problem. Consequently chlorine dioxide was tested and found to be a better biocide in controlling the bacterial population. A 2.0% Sodium-2-pyridinethiol-1-oxide solution had completely inhibited the fouling fungus. The paper discusses the importance of fungal adaptation in an industrial unit and highlights the biodeterioration of various sections of the WTP unit.

Tricuspid Valve Endocarditis.

We report a case of isolated native tricuspid valve infective endocarditis caused by Coagulase Negative Staphylococcus in a non-IV drug abuser without structural heart disease. Early diagnosis and prompt initiation of appropriate treatment saved the patient without surgical intervention. The recent trend of Coagulase Negative Staphylococci (CoNS) causing native valve endocarditis (NVE) is reviewed with literature.

Combinatorial Effects of Aromatic 1,3-Disubstituted Ureas and Fluoride on In vitro Inhibition of Streptococcus mutans Biofilm Formation.

Dental caries occur as a result of disequilibrium between acid producing pathogenic bacteria and alkali generating commensal bacteria within a dental biofilm (dental plaque). Streptococcus mutans has been reported as a primary cariogenic pathogen associated with dental caries. Emergence of multidrug resistant as well as fluoride resistant strains of S. mutans due to over use of various antibiotics are a rising problem and prompted the researchers worldwide to search for alternative therapies. In this perspective, the present study was aimed to screen selective inhibitors against ComA, a bacteriocin associated ABC transporter, involved in the quorum sensing of S. mutans. In light of our present in silico findings, 1,3-disubstituted urea derivatives which had better affinity to ComA were chemically synthesized in the present study for in vitro evaluation of S. mutans biofilm inhibition. The results revealed that 1,3-disubstituted urea derivatives showed good biofilm inhibition. In addition, synthesized compounds exhibited potent synergy with a very low concentration of fluoride (31.25-62.5 ppm) in inhibiting the biofilm formation of S. mutans without affecting the bacterial growth. Further, the results were supported by confocal laser scanning microscopy. On the whole, from our experimental results we conclude that the combinatorial application of fluoride and disubstituted ureas has a potential synergistic effect which has a promising approach in combating multidrug resistant and fluoride resistant S. mutans in dental caries management.

Development of a biofilm inhibitor molecule against multidrug resistant Staphylococcus aureus associated with gestational urinary tract infections.

Urinary Tract Infection (UTI) is a globally widespread human infection caused by an infestation of uropathogens. Eventhough, Escherichia coli is often quoted as being the chief among them, Staphylococcus aureus involvement in UTI especially in gestational UTI is often understated. Staphylococcal accessory regulator A (SarA) is a quorum regulator of S. aureus that controls the expression of various virulence and biofilm phenotypes. Since SarA had been a focussed target for antibiofilm agent development, the study aims to develop a potential drug molecule targeting the SarA of S. aureus to combat biofilm associated infections in which it is involved. In our previous studies, we have reported the antibiofilm activity of SarA based biofilm inhibitor, (SarABI) with a 50% minimum biofilm inhibitory concentration (MBIC50) value of 200 µg/mL against S. aureus associated with vascular graft infections and also the antibiofilm activity of the root ethanolic extracts of Melia dubia against uropathogenic E. coli. In the present study, in silico design of a hybrid molecule composed of a molecule screened from M. dubia root ethanolic extracts and a modified SarA based inhibitor (SarABI(M)) was undertaken. SarABI(M) is a modified form of SarABI where the fluorine groups are absent in SarABI(M). Chemical synthesis of the hybrid molecule, 4-(Benzylamino)cyclohexyl 2-hydroxycinnamate (henceforth referred to as UTI Quorum-Quencher, UTI(QQ)) was then performed, followed by in vitro and in vivo validation. The MBIC50 and MBIC90 of UTI(QQ) were found to be 15 and 65 µg/mL, respectively. Confocal laser scanning microscopy (CLSM) images witnessed biofilm reduction and bacterial killing in either UTI(QQ) or in combined use of antibiotic gentamicin and UTI (QQ) . Similar results were observed with in vivo studies of experimental UTI in rat model. So, we propose that the drug UTI(QQ) would be a promising candidate when used alone or, in combination with an antibiotic for staphylococcal associated UTI.

A Simple Label Switching Algorithm for Semisupervised Structural SVMs.

In structured output learning, obtaining labeled data for real-world applications is usually costly, while unlabeled examples are available in abundance. Semisupervised structured classification deals with a small number of labeled examples and a large number of unlabeled structured data. In this work, we consider semisupervised structural support vector machines with domain constraints. The optimization problem, which in general is not convex, contains the loss terms associated with the labeled and unlabeled examples, along with the domain constraints. We propose a simple optimization approach that alternates between solving a supervised learning problem and a constraint matching problem. Solving the constraint matching problem is difficult for structured prediction, and we propose an efficient and effective label switching method to solve it. The alternating optimization is carried out within a deterministic annealing framework, which helps in effective constraint matching and avoiding poor local minima, which are not very useful. The algorithm is simple and easy to implement. Further, it is suitable for any structured output learning problem where exact inference is available. Experiments on benchmark sequence labeling data sets and a natural language parsing data set show that the proposed approach, though simple, achieves comparable generalization performance.

Characterization of oats (Avena sativa L.) cultivars using machine vision.

Machine vision or image analysis is an important tool in the study of morphology of any materials. This technique has been used successfully to differentiate the eleven oats cultivars based on morphological characters. The geometry of seeds was measured through image analyzer and the variation was observed and recorded. From the recorded data, the cluster analysis was carried out and it revealed that the cultivars could be grouped into two main clusters based on similarity in the measured parameters. Cultivar Sabzar, UPO 212, OL 9 and OL 88 formed one main cluster. The another main cluster includes cv. Kent, OS 6, UPO 94, HFO 114, OS 7, HJ 8 and JHO 822 with many sub clusters. Among the cultivars HJ 8 and JHO 822 has more similarity in all measured parameters than other cultivars. Thus morphological characterization through seed image analysis was found useful to discriminate the cultivars.

4-Chloro-2-[(2,6-diisopropyl-phen-yl)imino-meth-yl]phenol.

The asymmetric unit of the title compound, C(19)H(22)ClNO, contains two independent mol-ecules in which the dihedral angles between the aromatic rings are 76.45 (9) and 74.69 (9)°. An intra-molecular O-H⋯N hydrogen bond occurs in each mol-ecule. The crystal structure features weak C-H⋯π inter-actions.

(E)-4-Bromo-2-[(2,6-diisopropyl-phen-yl)imino-meth-yl]phenol.

In the title compound, C(19)H(22)BrNO, the dihedral angle between the benzene rings is 76.17 (14)° and an intra-molecular O-H⋯N hydrogen bond with an S(6) graph-set motif is present. One methyl group is disordered over two sets of sites with site occupancies of 0.66 (3) and 0.34 (3). A weak inter-molecular C-H⋯π inter-action is observed in the crystal structure.

2-[(2,6-Diisopropyl-phen-yl)imino-meth-yl]-4-iodo-phenol.

The asymmetric unit of title compound, C(19)H(22)INO, contains two independent mol-ecules. Classical intra-molecular O-H⋯N hydrogen bonds stabilize the mol-ecular structures. The crystal structure is stabilized by weak inter-molecular C-H⋯π and π-π [centroid-centroid = 3.8622 (18) Å] inter-actions. In both mol-ecules, the aromatic rings are nearly perpendicular to each other [dihedral angles = 84.26 (17) and 86.69 (15)°].

Microbial fouling community analysis of the cooling water system of a nuclear test reactor with emphasis on sulphate reducing bacteria.

Culture and molecular-based techniques were used to characterize bacterial diversity in the cooling water system of a fast breeder test reactor (FBTR). Techniques were selected for special emphasis on sulphate-reducing bacteria (SRB). Water samples from different locations of the FBTR cooling water system, in addition to biofilm scrapings from carbon steel coupons and a control SRB sample were characterized. Whole genome extraction of the water samples and SRB diversity by group specific primers were analysed using nested PCR and denaturing gradient gel electrophoresis (DGGE). The results of the bacterial assay in the cooling water showed that the total culturable bacteria (TCB) ranged from 10(3) to 10(5) cfu ml(-1); iron-reducing bacteria, 10(3) to 10(5) cfu ml(-1); iron oxidizing bacteria, 10(2) to 10(3) cfu ml(-1) and SRB, 2-29 cfu ml(-1). However, the counts of the various bacterial types in the biofilm sample were 2-3 orders of magnitude higher. SRB diversity by the nested PCR-DGGE approach showed the presence of groups 1, 5 and 6 in the FBTR cooling water system; however, groups 2, 3 and 4 were not detected. The study demonstrated that the PCR protocol influenced the results of the diversity analysis. The paper further discusses the microbiota of the cooling water system and its relevance in biofouling.

Dense fouling in acid transfer pipelines by an acidophilic rubber degrading fungus.

An unique case of dense fouling by an acidophilic, hard rubber (polymerized rubber) degrading fungus in the acid transfer pipelines of a boron enrichment plant located at Kalpakkam, India is reported. In spite of a highly adverse environment for survival (pH 1.5, no dissolved nutrients), the fungus thrived and clogged the pipeline used for transferring 0.1N hydrochloric acid (HCl). Detailed investigations were carried out to isolate and identify the fungus and examine the nutrient source for such profuse growth inside the system. Microscopic observation showed the presence of a thick filamentous fungal biomass. Molecular characterization by 18S rRNA gene sequencing showed 98% similarity of the isolate with the acidophilic fungus Bispora sp. In laboratory studies the fungus showed luxuriant growth (specific growth rate of 13 mg day⁻¹) when scrapings of the hard rubber were used as the sole source of carbon. Scanning electron microscopy revealed extensive incursion of the fungus into the hard rubber matrix. In the laboratory, fungal growth was completely inhibited by the antifungal agent sodium omadine. The study illustrates an interesting example of biofouling under extreme conditions and demonstrates that organisms can physiologically adapt to grow under unfavourable conditions, provided that a nutrient source is available and competition is low. The use of this fungal strain in biodegradation and in development of environmentally compatible processes for disposal of rubber wastes is envisaged.