Indian Institute of Technology Hyderabad
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Assessing biological network dynamics: comparing numerical simulations with analytical decomposition of parameter space
Full text linkMathematical modeling of the emergent dynamics of gene regulatory networks (GRN) faces a double challenge of (a) dependence of model dynamics on parameters, and (b) lack of reliable experimentally determined parameters. In this paper we compare two complementary approaches for describing GRN dynamics across unknown parameters: (1) parameter sampling and resulting ensemble statistics used by RACIPE (RAndom CIrcuit PErturbation), and (2) use of rigorous analysis of combinatorial approximation of the ODE models by DSGRN (Dynamic Signatures Generated by Regulatory Networks). We find a very good agreement between RACIPE simulation and DSGRN predictions for four different 2- and 3-node networks typically observed in cellular decision making. This observation is remarkable since the DSGRN approach assumes that the Hill coefficients of the models are very high while RACIPE assumes the values in the range 1-6. Thus DSGRN parameter domains, explicitly defined by inequalities between systems parameters, are highly predictive of ODE model dynamics within a biologically reasonable range of parameters
Smartphone-powered, ultrasensitive, and selective, portable and stable multi-analyte chemiresistive immunosensing platform with PPY/COOH-MWCNT as bioelectrical transducer: Towards point-of-care TBI diagnosis
Full text linkTraumatic Brain Injury, one of the significant causes of mortality and morbidity, affects worldwide and continues to be a diagnostic challenge. The most desirable and partially met clinical need is to simultaneously detect the disease-specific-biomarkers in a broad range of readily available body fluids on a single platform with a rapid, low-cost, ultrasensitive and selective device. Towards this, an array of interdigitated microelectrodes was fabricated on commercially existing low-cost single-side copper cladded printed-circuit-board substrate followed by the bioelectrodes preparation through covalent immobilization of brain injury specific biomarkers on carboxylic functionalized multi-walled carbon nanotubes embedded polypyrrole nanocomposite modified interdigitated microelectrodes. Subsequently, the immunological binding events were transduced as the normalized change in bioelectrode resistance with and without the target analyte via current-voltage analysis. As proof of concept, current-voltage responses were primarily recorded using a conventional probe station, and later, a portable handheld-electronic-readout was developed for the point-of-care application. The data compilation and analysis were carried out using the in-house developed android-based mobile app. Notably, the smartphone powered the readout through a PL-2303 serial connector, avoiding integrating power sources with the readout. Further, this technology can be adapted to other point-of-care biosensing applications
Bio-waste assisted phase transformation of Fe3O4/carbon to nZVI/graphene composites and its application in reductive elimination of Cr(VI) removal from aquifer
No full textThis paper reports a facile approach for the synthesis of graphene stabilised zero valent iron (nZVI) via carbothermal reduction method using bio-waste materials. X-ray photoelectron spectroscopy confirmed the formation of nZVI, which was further supported by magnetic susceptibility measurements. The process of Cr(VI) removal was revealed by analysing nZVI/graphene before and after the Cr(VI) adsorption process. nZVI/graphene reduces Cr(VI) to Cr(III), which was adsorbed on the graphene sheet, avoiding the passivation of nZVI. Graphene provides good electrical conductivity, skeletal support, and has long-term electron releasing characteristics, which can accelerate the reduction of Cr(VI) to Cr(III) and demonstrates a quick and high removal capacity of Cr(VI) from an aquifer. The influence of Cr(VI) initial concentration, adsorbent dosages, equilibrium studies, solution pH, kinetics, adsorption isotherms, and thermodynamic parameters was also investigated. Synopsis. The green synthesis of nZVI/graphene composites for Cr(VI) reduction has not been well investigation. This paper reports a facile eco-friendly synthesis of nZVI/graphene composites for the removal of heavy metal contaminants from aquifers. © 2022 Elsevier B.V
Vision Transformer Based Damage State Assessment of Bridges using Wavelets of Earthquakes
No full textBridges play a crucial role in facilitating transportation and economic growth,
but their vulnerability to earthquakes necessitates effective damage detection
methods. This thesis explores the application of Continuous Wavelet Transforms
(CWT) in combination with Vision Transformers (ViTs) for automated detection and
assessment of structural damage in bridges. In the conventional approach, analytical
fragility curves, which quantify the likelihood of different damage states based on
ground shaking intensity, are employed to predict bridge damage. The study addresses
the limitations of conventional methods and introduces deep learning techniques to
enhance computational efficiency and accuracy. By analyzing a dataset of ground
motion records and training the ViT model, the research aims to advance automated
bridge inspection techniques and enable early damage detection. The results
demonstrate the effectiveness of the CWT-based ViT model in assessing the damage
state of bridges. The proposed approach holds promise for proactive maintenance
strategies, improving the safety and durability of critical infrastructure. Additionally,
the thesis discusses the influence of various factors such as rupture distance on
different bridge components and highlights the advantages of employing ViT models
in terms of computational cost. Future work involves expanding the dataset to improve
prediction accuracy and establishing a more uniform distribution of data for each
damage category
Newer approaches to dry eye therapy: Nanotechnology, regenerative medicine, and tissue engineering
Full text linkDefinitive treatment of dry eye disease (DED), one of the commonest ocular surface disorders, has remained elusive despite several recent advances in better diagnostics and the introduction of newer therapeutic molecules. The current treatment paradigms rely heavily on lubricating eye drops and anti-inflammatory agents that may need to be used long-term and are mainly palliative. Research is ongoing not only for a curative treatment option but also to improve the potency and efficacy of existing drug molecules through better formulations and delivery platforms. In the past two decades, significant advancement has been made in terms of preservative-free formulations, biomaterials such as nanosystems and hydrogels, stem cell therapy, and creation of a bioengineered lacrimal gland. This review comprehensively summarizes the newer approaches to DED treatment, which are biomaterials such as nanosystems, hydrogels, and contact lenses for drug delivery, cell and tissue-based regenerative therapy for damaged lacrimal gland and ocular surface, and tissue engineering for developing artificial lacrimal gland. Also, their potential efficacies in animal models or in vitro studies and possible limitations are discussed. The ongoing research looks promising and needs to be supported with clinical efficacy and safety studies for human use
Green synthesis of multi-functional carbon dots from medicinal plant leaves for antimicrobial, antioxidant, and bioimaging applications
Full text linkIn this research work, carbon dots (CDs) were synthesized from the renewable leaves of an indigenous medicinal plant by the one-pot sand bath method, Azadirachta indica. The synthesized CDs were characterized for its optical properties using UV–Vis, Fluorescence and Fourier transform infrared (FT-IR) spectrophotometry and for structural properties using dynamic light scattering (DLS), X-ray Diffraction (XRD) and high resolution Transmission electron microscopy (HR-TEM). The synthesized CDs exhibited concentration dependent biocompatibility when tested in mouse fibroblast L929 cell line. The EC50 values of biomedical studies, free radical scavenging activity (13.87 μgmL−1), and total antioxidant capacity (38 μgmL−1) proved CDs were exceptionally good. These CDs showed an appreciable zone of inhibition when examined on four bacterial (two gram-positive and gram-negative) and two fungal strains at minimum concentrations. Cellular internalisation studies performed on human breast cancer cells (MCF 7- bioimaging) revealed the applicability of CDs in bioimaging, wherein the inherent fluorescence of CDs were utilised. Thus, the CDs developed are potential as bioimaging, antioxidants and antimicrobial agents
Experimental and numerical study on behaviour of fibre reinforced lightweight hollow core slabs under different flexure to shear ratios
Full text linkThe current work explores the behaviour of fibre-reinforced lightweight hollow core slabs (FR-LWHCS) intending to develop sustainable construction solutions. The FR-LWHCS investigated in this work contains sintered fly ash aggregate (SFA) as coarse aggregate. Due to the use of SFA, the behaviour of LWHCS is expected to be different from the hollow core slabs (HCS) constructed using normal density concrete. FR-LWHCS are tested at different shear span to depth (a/d) ratios of 3.5, 7 and 10 to understand the shear and flexure behaviour. Twelve full-scale hollow core slab (HCS) specimens of 3400 mm length, 600 mm width, and 150 mm thickness are tested. FR-LWHCS consists of monofilament macro synthetic fibre dosages of 0.4 %, and 0.6 %, along with fibrillated micro fibre of 0.02 % dosage. The digital image correlation (DIC) technique is adopted to understand the strain profile on the HCS at different levels of loading. The numerical analysis is performed using a commercially available finite element software and is corroborated with experimental findings and parametric studies have been performed. Both LWHCS and normal HCS specimens failed in shear, flexural-shear and flexure modes at a/d ratios of 3.5, 7 and 10, respectively. The addition of fibres increased the peak load by 65 % compared to control LWHCS specimens tested at an a/d ratio of 3.5. The use of fibres increased strain energy absorption and changed the failure to less brittle mode at all a/d ratios. The fibre reinforced specimens have nearly 3.5 times, 2.5 times and 1.3 times the strain energy absorption of the control LWHCS when tested at a/d ratio 3.5, 7 and 10 respectively
Non-stationary crash risk modelling of powered two-wheelers using extreme value analysis of surrogate crash events
Full text linkEvaluating the impact of evasive actions such as braking and steering on the crash risk assessment of vehicles is a scarce endeavor due to the lack of relevant data. This study uses Extreme Value Theory to investigate and model the effect of evasive actions on the sideswipe crash risk of powered two-wheelers (PTWs) moving on multilane rural highways. The crash risk was projected from the observed sideswipe conflicts that were quantified using a surrogate safety indicator called anticipated collision time (ACT). The vehicle trajectory data extracted from traffic videos, collected using an unmanned aerial vehicle, was used as the input for the analysis. The data was denoised using a state-of-the-art trajectory reconstruction method called recursively ensembled low pass filtering. Once the conflicts were identified from the trajectory data, the crash risk models were developed considering five covariates: maximum deceleration rate, maximum yaw rate, and the times spent in decelerating, accelerating, and steering during a sideswipe conflict. These covariates were used to capture the non-stationarity in the traffic conflict extremes. The best performing non-stationary model was selected by comparing the negative log-likelihood values with the stationary-one. The findings suggest that the PTWs experience significant sideswipe crash risk on four-lane (crash risk 0.09%) and six-lane (crash risk 0.17%) highways. The sideswipe crash risk of PTWs increases with the increase in the intensity of braking and steering actions measured in terms of maximum deceleration and yaw rates. Further, this study emphasizes that incorporating the effects of evasive actions in the crash risk estimation and developing non-stationary models could significantly improve the precision of crash frequency estimates. Based on the findings it can be concluded that for the safety improvement of PTWs on multilane highways, lane-restriction should be imposed which can increase the safety margin during sideswipe conflicts
Ergodic-nonergodic relaxor behavior, recoverable energy storage density, and dynamic hysteresis scaling in NKBT ferroelectrics
No full textThe present study examined the scaling behavior of the room temperature ferroelectric hysteresis and switching current curves for lead-free and eco-friendly K+1 rich NBT (Na0.5Bi0.5TiO3) -based compositions. The scaling behavior between the logarithms of the hysteresis area and the logarithm of the amplitude (E) of the field evolve in three regions for all the compositions. Three different stages have been described in detail with the amplitude of the electric field (E). The domain dynamic behavior in different regions has been revealed with the help of the power scaling law. Based on the shape, size, and value of the Polarization (P), switching current (I), and, Strain curve (S), the evolution of relaxor phases and domain switching mechanism were studied for the K+1—rich substituted NBT. The recoverable energy storage density (Wrec) of the material is also influenced by the shape of the P–E loop and analyzed by scaling of Wrec. Interestingly, three regions had been observed in the ln Wrecvs ln E graph for the pinched type P–E loop, whereas the graph showed linear relation for the slanted type of loop. Although all of the compositions in this study exhibited good Wrec, the optimum Wrec was found to be 0.5 J/cm3 for NKBT-30, which showed a breakdown strength of 79 kV/cm. We also established a complete scenario for the NKBT series in terms of the evolution of relaxor nature based on the ferroelectric properties and their applications
A test of linearity of the ratio of dark matter to baryonic matter in galaxy clusters
Full text linkWe search for a linearity in the ratio of dark matter to baryonic matter as a function of radius for galaxy clusters, motivated by a recent result by Lovas (2022), who has discovered such a linearity for a diverse suite of galaxies in the SPARC sample. For our analysis, we used a sample of 54 non-cool core clusters from the HIFLUGCS sample. We do not find any evidence for a linear trend in the aforementioned ratio as a function of radius for individual clusters. We then repeat this analysis for the stacked sample, which also does not show this linearity. Therefore, the linear scaling found by Lovas is not a universal property of dark matter haloes at all scales