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AstroSat's view of kHz quasi-periodic oscillations from 4U 1820?30
This study presents the spectro-temporal analysis of the neutron star low mass X-ray binary 4U 1820?30, using data from three observations conducted by AstroSat 's Soft X-ray Telescope and Large Array X-ray Proportional Counter. Spectral analysis revealed that the source spectra could be modelled using an absorbed blackbody and a multi-temperature disk model along with a Comptonization model with ?=1.24 ? 1.89 and the inner accretion disk located at an distance of ?17 km from the neutron star. This showed the source to be in the hard spectral state. Temporal analysis revealed the presence of kHz quasi-periodic oscillations (QPOs) with frequencies in the 640 ? 1090 Hz range with root mean squared (RMS) amplitudes between 6 ? 10 per cent and quality factors between 8 ? 42. The RMS amplitude?energy and time lag?energy spectra of the upper and lower kHz QPOs hint them to be caused by modulations of photons having a common radiative mechanism. Moreover, the maximum RMS amplitude and time lag exhibited an anti-correlation with mass accretion rate. Using an analytical relation based on the relativistic precession model, the mass of the neutron star in the system was estimated to be 1.8 M?. The emission radius of one of the detected kHz QPOs was estimated to be ? 17 km. 2025 Elsevier B.V. -
Clues on the X-ray emission mechanism of blazars PKS 2155?304 and 3C 454.3 through polarization studies
X-ray polarization measurable with the imaging X-ray Polarimetry Explorer (IXPE) could constrain the long debated leptonic versus hadronic origin for the high energy component in the broad band spectral energy distribution (SED) of blazars. We report here the results from IXPE and SED modeling of PKS 2155?304 and 3C 454.3, a high and low synchrotron peaked blazar. For PKS 2155?304, from model-independent analysis, we found polarization angle ?X = (130 2.5) deg and polarization degree ?X = (20.9 1.8)% in the 2?8 keV band in agreement with spectro-polarimetric analysis. We found ?X to vary with time and indications of it to vary between energies, suggesting that the emission regions are stratified. For 3C 454.3, we did not detect X-ray polarization in the June 2023 observation, analyzed here for the first time. The detection of X-ray polarization in PKS 2155?304 and its non-detection in 3C 454.3 is in accordance with the X-ray emission from synchrotron and inverse Compton process, respectively, operating in these sources. Further, our division of the dataset into finer time bins allows a more granular view of polarization variability. Additionally, we modeled the broadband SEDs of both the sources using data acquired quasi-simultaneously with IXPE, in the optical, UV and X-rays from Swift, AstroSat and ?-rays from Fermi. In PKS 2155?304, the observed X-ray is found to lie in the high energy tail of the synchrotron component of the SED, while in 3C 454.3 the observed X-ray lies in the rising part of the inverse Compton component of the SED. Our SED modeling along with X-ray polarization observations favor a leptonic scenario for the observed X-ray emission in PKS 2155?304. The SED modeling for these specific IXPE epochs has not been presented before, allowing us to place additional constraints on the physical conditions in the jet. These results strengthen the case for a structured jet model where X-ray emission originates from a compact acceleration zone near the shock front, while lower-energy optical emission is produced in a broader, more turbulent region. 2025 Elsevier B.V. -
Spectral and type I X-ray burst studies of M15 X-2 using NICER observations
In this work, we present spectral and burst analyses of three thermonuclear type I X-ray bursts (B1, B2, and B3) detected from the ultracompact neutron star low-mass X-ray binary M15 X-2, using data from the Neutron Star Interior Composition Explorer (NICER). Time-averaged spectral fitting with the model tbabsthcompiskbb) suggests that the source was in a soft or soft-intermediate spectral state, characterized by a photon power law index of ??2 and an average mass accretion rate of ?0.09 m?Edd. The type I X-ray bursts exhibited rapid rise times of 1.25?2.75 s, followed by longer decay phases lasting 14.50?23.25 s, with characteristic burst timescales (?) of ?11 s, which are consistent with pure helium burning. Notably, burst B3 displayed a double-peaked profile indicative of a photospheric radius expansion event, from which we inferred the neutron star radius to be 10.8+2.4?2.2 km. Based on the peak flux of the burst, we estimated the source distance to be 10.54+1.43?1.26 kpc under the assumption of isotropic emission, and 14.06+1.90?1.68 kpc for anisotropic emission geometry. A strong ?420 Hz burst oscillation candidate was detected in the cooling tail of burst B1. 2025 Elsevier B.V. -
Modelling the energy dependent X-ray variability of Mrk 335
We present a technique which predicts the energy dependent fractional r.m.s. for linear correlated variations of a pair of spectral parameters and apply it to an XMM-Newton observation of Mrk 335. The broadband X-ray spectrum can be interpreted as a patchy absorber partially covering the primary emission, a warm and hot coronal emission or a relativistically blurred reflection along with the primary emission. The fractional r.m.s. has a non-monotonic behaviour with energy for segments of lengths 3 and 6 ksecs. For each spectral model, we consider every pair of spectral parameters and fit the predicted r.m.s. with the observed ones, to get the pair which provides the best fit. We find that a variation in at least two parameters is required for all spectral interpretations. For both time segments, variations in the covering fraction of the absorber and the primary power law index gives the best result for the partial covering model, while a variation in the normalization and spectral index of the warm component gives the best fit in the two corona interpretation. For the reflection model, the best fit parameters are different for the two time segment lengths, and the results suggests that more than two parameters are required to explain the data. This, combined with the extreme values of emissivity index and reflection fraction parameters obtained from the spectral analysis, indicates that the blurred reflection model might not be a suitable explanation for the Mrk 335 spectrum. We discuss the results as well as the potential of the technique to be applied to other data sets of different AGN. 2025 Elsevier B.V. -
Comprehensive spectro-temporal studies of GX 17+2 using AstroSat observations
We performed a comprehensive spectro-temporal study of the Z-type neutron star low-mass X-ray binary GX 17+2 using long term data from the AstroSat/Soft X-ray Telescope (SXT) and Large Area X-ray Proportional Counter (LAXPC). The hardnessintensity diagrams (HIDs) of the source revealed a positive correlation between the hardness and intensity, characteristic of soft spectral state. Additionally, the LAXPC-20 HID showed the presence of secular shifts in both hardness and intensity. Time-averaged spectral modelling in the 0.7 ? 30.0 keV energy range indicated that the spectra could be well fitted with the model combination: constant edge edge tbabs thcomp bbodyrad. This analysis yielded a blackbody radius (Rbb) of ?59 km, photon index (?) of ?2.84 and electron temperature (kTe) of ?4.84 keV. Time-averaged temporal analysis revealed normal branch oscillations (NBOs) at ? 7 Hz in Observations 1 and 3, flaring branch oscillation (FBO) at ?15 Hz in Observation 2, and horizontal branch oscillation (HBO) at ?36 Hz in Observation 5. Flux resolved spectro-temporal analysis indicated that the source remained in the soft spectral state throughout all observations. A positive correlation was observed between kTbb, Fbb and Fbol, whereas an anti-correlation was noted between kTe and Fbol. The constant frequency of NBOs with an increase in Fbol suggests that their origin lies in a region strongly influenced by the corona, as explained by the radiation-hydrodynamic model. The origin of FBOs may be attributed to the damped radiation-hydrodynamic mode of radial flow, while the origin of HBOs is supported by the beat-frequency model. 2024 Elsevier B.V. -
An efficient reconfigurable band tuning filter design for channelizer in transponder satellite system
For improved performance in a variety of applications, the transponder in satellite systems must be very flexible. The channelizer-dependent transponder system significantly boosts the operation of a satellite system. When channelizing wideband input signals, a digital filter bank is typically used to extract several small sub-bands. In this research, a reconfigurable band tuning (RBT) design for the channelizer in the satellite transponder system is designed and implemented. Cosine modulation, exponential modulation and IFIR filter are the techniques behind the RBT design. The RBT design facilitates the generation of many channels enabling channelization with non-uniform narrow transition width. A number of examples are presented to illustrate how well the RBT design performs. Findings indicate that there are fewer filter coefficients in the RBT design than there are in the current approaches Effective implementation of a properly designed RBT design lowers power consumption and simplifies the hardware. 2024 The Franklin Institute -
Physicochemical characterization of fluoride solid electrolyte PbSnF4 synthesized via sonochemical reaction
Demand for batteries with enhanced energy density and improved thermal safety is a key focus for researchers striving to build a sustainable environment. As fluoride ion batteries (FIB) are expected to exhibit high energy density and exceptional thermal stability, research activities are focused on identifying fluoride ion-conducting electrolytes. Among the various fluoride ion conductors, PbSnF4, renowned for its superior ionic conductivity, is typically synthesized via mechanochemical reaction. In the present work, PbSnF4 was synthesized via an acoustic cavitation-driven sonochemical reaction. This novel synthesis route has reduced the duration of the synthesis process to a few minutes compared with several hours for the mechanochemical reaction. The structural, morphological, and ionic transport properties are investigated. The ionic conductivity of the resulting orthorhombic PbSnF4 is evaluated to be 4.5 10?4 S/cm at RT. The contribution of fluoride ions to the total ionic conductivity is estimated via the DC polarization technique as 0.92. The electrochemical stability window (ESW) is measured through cyclic voltammetry (CV) as 0.7 V with PbF2/PbSnF4/SS cell configuration. 2025 -
Paraquat associated stomatitis: A forensic marker of exposure intent and prognosis
Introduction: Paraquat-associated stomatitis (PAS) is a hallmark of paraquat poisoning but its potential as an intent-specific or prognostic marker remains unexplored. This study investigated whether PAS patterns differ between accidental and suicidal exposures. Methods: A pooled, individual case analysis of 170 paraquat poisoning cases from 122 publications was conducted following PRISMA guidelines. Data on demographics, exposure intent, and detailed oral lesion characteristics (morphology, pattern, severity) were extracted. Statistical analyses identified predictors of intent and prognosis. Results: Oral lesions were present in 78.8% of cases. While the overall prevalence of PAS did not differ between accidental (85.1%) and suicidal (83.9%) intents, lesion morphology was a key differentiator. Widespread ulcers were strongly associated with suicidal ingestion (aOR=6.37; 95% CI 1.9520.78; P=0.002), independent of lesion severity or WHO grade. Conversely, focal but objectively more severe ulcers characterized accidental exposures. Lesion morphology, not severity, distinguishes intent. Other independent predictors of suicidal intent included female sex (aOR=3.40; P=0.031), oliguria (aOR=4.21; P=0.006), and delayed treatment (aOR=8.39; P=0.023). Paradoxically, accidental exposures were associated with significantly higher mortality (68.9%) compared to suicidal cases (39.8%) (P=0.001). The absence of PAS reliably indicated a non-oral exposure route (P<0.001). Discussion: This work introduces the novel concept of intent-specific PAS morphology, establishing ulcer pattern as a forensic marker. It is demonstrated, for the first time, that widespread lesions objectively indicate suicide, while focal, severe ulcers signify accidental exposurea finding linked to a paradoxical mortality risk. This intent-specific signature could provide clinicians with a rapid, objective tool for stratification. For medicolegal investigations, it qualifies PAS as crucial physical evidence to clarify disputed histories, advocating for its systematic documentation in clinical and autopsy practice as a new standard in forensic toxicology. 2026 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights are reserved, including those for text and data mining, AI training, and similar technologies. -
A novel image compression method using wavelet coefficients and Huffman coding
Compressing medical images to reduce their size while maintaining their clinical and diagnostic information is crucial. Because medical images can be large and demand a lot of storage and transmission capacity, effective compression methods aid medical institutions in better storing and transmitting medical images, reducing costs, speeding up data transfer, and simplifying managing image databases. However, it is essential to note that image compression in medical imaging can also introduce drawbacks, such as loss of information and poor output image quality. Therefore, a suitable compression algorithm and parameter must be chosen to balance file size and visual fidelity. This paper suggests an effective image compression method employing the Discrete Wavelet Transform (DWT), followed by a reduction operation and Huffman coding to produce a mere lossless encoding to transmit the images over a channel. The extracted DWT coefficients are mapped to the nearest integral value. All four sub-bands of DWT are joined, and then a window of 3 3 is selected for reduction operation by choosing the origin as the pivot element. The Huffman coding algorithm is used to compress the processed image. The pivot origin element is used in the reversible reduction while uncompressing the image. When sending compressed data across an unreliable route, the window size and pivot element selection keep the compressed data secure. Standard measures such as bits per pixel (BPP) and compression ratio (CR) are used to assess the suggested approach. The efficiency of the suggested course of action is supported by the research's findings, which use a peak signal-to-noise ratio (PSNR) of 54.66 dB. 2023 The Authors -
Climate change and health risk perception in India: A replication of the climate change risk perception model
Behavioral science insights into attitudinal antecedents of climate change risk perception in India are limited. Addressing the lack of nationally diverse samples in environmental psychology research, this study replicates the climate change risk perception model (CCRPM, van der Linden, 2015) in the Indian context. In a nationally comparable sample (N = 749), participants were measured on sociodemographic, cognitive, experiential, and socio-cultural factors associated with climate risk perception. Results of hierarchical regression analyses found that the CCRPM explained 32.85 % of climate change risk perception. Confirmatory factor analysis outcomes empirically support a two-factor structure of risk perception, personal, and societal/generalized in the Indian context. Moreover, the CCRPM explains limited (19.5 %) variance in perceptions of health risks associated with climate change. Experiential factors (such as affect, and personal experience) and prescriptive norms were strongly associated with climate change and health risk perception in India. Highlighting the vulnerabilities associated with health and climate change may prove essential to communicating climate change risks in India. 2025 Elsevier Ltd -
Surveilling bodies, governing morality: Biopower and the contagious diseases acts in colonial India
This article explores the Contagious Diseases Acts (CD Acts) in colonial India using Michel Foucault's theory of biopower, focusing on their impact on devadasis. The Acts subjected women's bodies to medical and legal scrutiny, pathologizing female sexuality while reinforcing patriarchal and caste hierarchies. Devadasis, historically associated with temple practices, were recast as vectors of disease and moral disorder, aligning with the colonial administration's broader project of governance through regulation and surveillance. This study examines how the CD Acts functioned as a technology of power, reshaping devadasis identities and controlling their bodies to sustain social and political order. It also investigates how these mechanisms were challenged by resistance, demonstrating the adaptive and contested nature of colonial power. By situating the devadasis within the framework of biopower, this analysis illuminates the intersection of health policies, sexuality, and governance in shaping colonial hierarchies and marginalizing vulnerable communities. 2025 Elsevier Masson SAS -
Leveraging QSPR-guided ZIF selection for MWCNTs/ZIF-8 platforms for electrochemical immunosensing of lactoferrin
This study presents a data-driven workflow integrating quantitative structureproperty relationship (QSPR) modelling with Monte Carlo (MC) adsorption simulations to guide zeolitic imidazolate framework (ZIF) selection for lactoferrin (LF) immunosensing.MC simulations calculated adsorption energies (Eads) of LF across 27 ZIFs, represented using MOFid/MOFkey-encoded SMILES notation, enabling construction of a predictive QSPR model (top-performing model: PLS, R2=0.891, Q2=0.888). The model successfully ranked ZIFs according to predicted LF affinity, with ZIF-8 emerging as the optimal candidate based on computational predictions, structural robustness, and synthetic accessibility. Following computational validation through molecular docking, ZIF-8 was integrated with multiwalled carbon nanotubes (MWCNTs) on a glassy carbon electrode (GCE), enabling noncovalent immobilization of anti-LF antibodies. Electrochemical measurements performed using square-wave voltammetry (SWV) with a ferri/ferrocyanide [Fe(CN)6] 3?/4- redox probe demonstrated a linear response over 1060ng/mL LF (R2=0.994), a limit of detection (LOD) of 4.78ng/mL, and recoveries of 95105% in spiked milk samples with reproducibility ?8% RSD (n=3). Shelf-life studies showed 74% signal retention after four weeks of storage at 4C. Electrochemical analysis revealed a synergistic enhancement of charge transfer (Rct) in the MWCNTs/ZIF-8 composite (0.572k? vs. 12.79k? for bare GCE). This work demonstrates a transferable, computationally driven framework for screening framework materials in MOF/ZIF-based biosensors, bridging predictive materials design with experimental device fabrication for broad applications in clinical diagnostics and food quality monitoring. 2026 Published by Elsevier B.V. -
Recent trends in the transformative impact of biomass-derived carbon dots in biomedical science
Carbon dots (CDs) have gained significant attention from researchers due to their unique properties, which make them a promising option among nanomaterials for biomedical use. From recent trends, it is confirmed that CDs are the best candidates available among nanomaterials for the treatment of various diseases, including Ulcer, Diabetes, Gout, Wound healing and other syndromes. Semiconductor dots, which dominated in the early days, have been replaced by biomass-derived CDs (BCDs) due to their low toxicity, biocompatibility, and ease of synthesis. Although extensive research has been carried out on the applications of CDs in the biomedical field, the use of biomass as a precursor for CDs in therapeutic and clinical applications remains least explored and has not been systematically reviewed. This review primarily focuses on synthesis strategies, factors influencing the biomedical use of CDs, and recent research in therapeutic and clinical applications. In addition, the earlier trend of employing BCDs in bioimaging, biosensing, and molecular detection is also discussed. By examining the latest research developments, we provide a comprehensive overview of the progress and future prospects of BCDs in healthcare. This exploration highlights not only the potential of these sustainable nanomaterials but also their promise in enabling new breakthroughs in disease treatment. 2025 Elsevier Ltd. -
Silver decorated copper coordination polymer for the electroreduction of CO2 to hydrocarbon liquid fuels
Recently, the development of bimetallic interfaces has emerged as a promising strategy for enhancing electrocatalytic CO2 electroreduction (CO2ER) efficiently, with selectivity towards energy-dense hydrocarbons. In this study, we report an electrochemically designed silver-decorated copper-dimercapto thiadiazole modified carbon electrode (Ag@Cu-DM), which facilitates a controlled transition from C1to C2liquid products. The optimized electrochemical synthesis method enabled precise control over the polymer-metal interface, promoting strong electronic interactions and charge transfer. The multiple characterizations conducted for the material revealed distinct lattice fringes corresponding to well-defined Cu and Ag phases. The interplay between Cu and Ag, along with the heteroatoms present within the polymer enhances CO2 activation and intermediate stabilization. The developed Ag@Cu-DM catalyst achieved 89 % F.E. for liquid products alone at a low potential of -0.73 V vs RHE and also demonstrated stable electrolysis for upto 8 Hr. 2025 Elsevier Ltd. All rights reserved. -
Functional carbon nanospheres from mulberry leaves for improved flux, fouling resistance and dye rejection
Carbon-based nanomaterials obtained from biological sources have emerged as promising candidates for advanced water remediation. In this research, carbon nanospheres (CNS) were synthesized using a one-step pyrolysis method, utilizing mulberry leaves as a precursor. The CNS were further modified through surface functionalization with the addition of carboxyl groups to enhance surface hydrophilicity, contributing to improved membrane performance. The functionalized carbon nanospheres (FCNS) ranging from 0.1 to 0.6 wt% were incorporated into Polysulfone (PSF) membranes. Scanning electron microscopy (SEM) analysis revealed the spherical nature and average size found to be 6070 nm. The PSF/FCNS composite membranes were casted via phase inversion method. The fabricated PSF/FCNS composite membranes with 0.0, 0.1, 0.2, 0.4 and 0.6 wt% FCNS concentrations were defined as M-0, M-1, M-2, M-3 and M-4 respectively. SEM, Contact angle, Pure water flux and Antifouling ability using Bovine serum albumin (BSA) were conducted to achieve the target of this paper. Among the developed membranes, the M-2 variant, with 0.2 wt% FCNS, demonstrated optimal performance, exhibiting improved hydrophilicity from 77.49 to 65.48 and reduced surface roughness. This resulted in an increased pure water flux (PWF) of 632.5 L m?2 h?1 and a flux recovery ratio (FRR) of 93.54 %. Furthermore, M-2 achieved dye rejection rates 96.5 % and 95 % for methylene blue and congo red, respectively. These findings underscore the potential of low-cost, bio-derived FCNS as efficient nanofillers for developing high-performance membranes, offering a suitable approach to tackle the multifaceted challenges of water treatment applications. 2025 Elsevier Ltd -
Plant extract aided synthesis of iron sulphide/nickel sulphide type-II heterostructure for photochemical CO2 reduction and simultaneous degradation of dyes
The green synthetic route, solving issues in the energy sector and the removal of wastes for a clean environment are the major concerns across the globe for a sustainable future. The current work involves the synthesis of iron sulphide (FeS), nickel sulphide (NiS) and FeS/NiS heterostructure using a Calotropis procera leaf and flower extract as a reducing agent without any additional sulphur source. Structural optical, photo/electrochemical and morphological characterizations suggest the formation of a heterostructure between FeS and NiS of type II with tuned edge potentials. Due to which FeS/NiS showed enhanced activity in evolving CO and CH? through photoctalytic CO2 reduction reaction (CRR) and was found to be 2.5 and 2 times higher than FeS and NiS, respectively. Further, all three materials were studied for photocatalytic degradation of two cationic dyes (methylene blue: MB and safranin O: SO) under different light sources. The % degradation of dyes MB and SO was found to be 98 and 96 %, respectively, in the presence of FeS/NiS heterostructure under sunlight. The factors affecting the dye degradation (pH, initial concentration, catalyst dosage) were optimized to achieve maximum efficiency. The degradation study using FeS/NiS was additionally examined in industrial effluent and the simultaneous degradation of MB and SO and the results are satisfactory. Photocatalytic mechanism was predicted based on the degradation results using liquid chromatography mass spectrophotometry (LCMS). The decreased charge transfer resistance, superior photocurrent response, bandgap tuning, shift in edge potentials, and formation of heterostructure and effective charge separation could be attributed to the appreciable efficiency of FeS/NiS. This work may lead to further research on the formation of metal sulfide-based heterostructures using a green approach and their application towards waste reduction and converting them to wealth towards energy and environmental remediation. 2025 Elsevier Ltd -
Biofunctional TiVO4chitosanL-histidine hybrid nanomaterials for enhanced antimicrobial and anticancer applications
The growing pervasiveness of multidrug-resistant (MDR) pathogens and the limitations of conventional chemotherapeutics demand the development of multifunctional nanomaterials with enhanced efficacy and biocompatibility. In this study, titanium vanadate (TiVO4) nanoparticles and TiVO4chitosanL-histidine (TiVO4CsLH) HNM's were successfully synthesized via a wet chemical solgel route followed by surface functionalization. Structural analysis confirmed the formation of phase-pure tetragonal TiVO4 with an average crystallite size of ?38 nm, which was significantly reduced to ?24 nm upon CsLH functionalization. UVVisible spectroscopy revealed band gap narrowing from 4.75 eV (TiVO4) to 4.15 eV (TiVO4CsLH), indicating modified electronic structure and improved light absorption. The TiVO4CsLH HNM's exhibited superior broad-spectrum antimicrobial activity, with inhibition zones ranging from 18 to 19 mm against Gram positive, Gram negative and fungal strain, outperforming TiVO4. In vitro anticancer evaluation against MCF-7 breast cancer cells demonstrated pronounced concentration- and time-dependent cytotoxicity, with IC50 values decreasing from 29.8 ?g mL?1 (24 h) to 20.6 ?g mL?1 (72 h), significantly lower than those of TiVO4. Biocompatibility studies using L929 fibroblast cells revealed high cell viability (>82%) even at 60 ?g mL?1, which confirms the selective anticancer activity of TiVO4-Cs-LH HNMs. The enhanced biological performance of the TiVO4CsLH HNM's arose from synergistic effects of reduced crystallite size, improved dispersion, defect-assisted charge separation, and biofunctional surface chemistry, making it a promising candidate for antimicrobial and anticancer applications. 2026 Elsevier B.V. -
Biocompatible NiTiO3Dopamine nanocomposites for combating drug-resistant pathogens through membrane disruption and oxidative stress
The rising threat of multidrug-resistant pathogens poses a challenge to public health. Highlighting the urgent need for novel antimicrobial agents, this study reports the synthesis of NiTiO3 nanoparticles and dopamine-functionalized NiTiO3 nanocomposites. Structural and elemental confirmation was obtained through XPS studies, which confirmed the presence of Ni2+ and Ti4+ in the nanocomposite, along with C 1s and O 1s peaks corresponding to dopamine coating. Photoluminescence spectra revealed that the NiTiO3dopamine nanocomposite exhibits notable green emission bands at 510, 518, and 527nm which arises from deep-level recombination associated with complex oxygen-related defects like oxygen vacancies. The NiTiO3-dopamine exhibited enhanced antimicrobial activity against S. aureus, B. subtilis, K. pneumoniae, S. dysenteriae, and C. albicans, compared to NiTiO3 alone. Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) assays further revealed that NiTiO3dopamine achieved MIC at 600?g/mL and MBC at 1000?g/mL for K. pneumoniae, outperforming pure NiTiO3. ROS assays confirmed oxidative stress-mediated antimicrobial action, with ROS levels significantly quenched in the presence of histidine. SEM images of bacterial morphology showed extensive membrane disruption in NiTiO3dopamine treated cells. Furthermore, zebrafish embryo assays confirmed excellent biocompatibility of the NiTiO3dopamine nanocomposite, with normal development observed up to 72h post fertilization. 2025 Published by Elsevier B.V. -
Construction of multifunctional hyaluronic acid modified gold nanoparticles clocked with Irinotecan and indocyanine green: Investigation of chemotherapy and cancer cell imaging
To overcome the inherent limits of conventional cancer therapy, there is an immediate need to establish multifunctional drugs that combine accurate diagnosis with treatment. The work describes a small nanocomposite's mild and easy fabrication, including Irinotecan, folic acid, hyaluronic acid, and indocyanine green-integrated gold nanoparticles. The gold nanoparticles with indocyanine green integrated (HA@ICG/Au) were developed in one step for photodynamic treatment and biological fluorescence imaging. Both the drug delivery of Irinotecan and the enhancement of cellular selectivity are achieved by the hyaluronic acid-altered ICG/Au (HA@ICG/Au). To regulate the release of Irinotecan during tumour chemotherapy, the dual-targeted and pH-responsive system known as HA@ICG/Au:FA@IRI was developed. The nanocomposite composed of HA@ICG/Au:FA@IRI had a tiny surface area and was highly efficient at encapsulation and loading drugs. In an acidic milieu, the nanocomposite showed excellent biocompatibility, colloidal stability, photostability, and a rapid cumulative release rate. The improved cellular uptake of HA@ICG/Au:FA@IRI for fluorescence imaging was validated by fluorescence microscopy in vitro. The nanocomposite showed impressive cancer cell death when exposed to laser irradiation using a combination of synergistic chemotherapy and photodynamic treatment (PDT). Taken as a whole, the results show that the nanocomposite was successfully developed to target tumors in two different ways, resulting in a potentially helpful theranostics agent. 2025 Elsevier B.V. -
Directional injection-driven contaminants transport in groundwater system with asymptotically varying dispersion coefficients
This work examines the effect of asymptotic dispersion for different contaminants, like heavy metals, biological, and radiological types, in heterogeneous groundwater systems. The migration of contaminants within groundwater systems is controlled by advection, dispersion, and sorption phenomena, and these mechanisms are mathematically modeled using the Advection-Dispersion Equation (ADE). Using the Thomas algorithm, a numerical simulation with the Peaceman - Rachford Alternating Direction Implicit (PR-ADI) scheme is applied to solve the ADE under the directional injection boundary (axial input sources). The study on asymptotic dispersion coefficients revealed a broader plume evolution. Non-linear sorption models depended on the saturation limit, and various parameters revealed physically relevant results. The iso-concentration figures depict flow patterns for diverse directional hydrological inflows, supporting stability interpretations. This study introduces a computational approach for modeling contaminant transport in groundwater systems, emphasizing asymptotic field conditions that introduce heterogeneity, coupled with nonlinear sorption effects on the plume morphology. The results highlight how plume morphology responds to variable dispersion and velocity, offering guidance for field-scale aquifer analysis and water quality management. The study is also aligned with Sustainable Development Goal 6 - Clean water and sanitation. 2025 Elsevier B.V.