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Development of Electrochemical Sensors for the Detection of Pesticide Residues in Water
No full textIntentional and unintentional events of pesticide poisoning and their accidental exposure have significantly raised the concerns of global organizations to classify these chemical compounds based on their toxicity, to assign permissible limits, and to appoint task force for periodic monitoring of their presence in water bodies.
In this context, researchers are continually seeking potential alternatives to develop water quality sensors with higher selectivity to obtain the desired performance during real-time assessment. Electrochemical sensors involving interface materials of distinguishing capacity at elevated matrix complexity are desirable. However, there remains a challenge in designing suitable techniques, methodologies, and appropriate validations to support the grounds for the selection of interface materials.
The ability to monitor imidacloprid, carbendazim, and chlorpyrifos pesticides in water matrix using interface materials of suitable states is the major focus of this work. To achieve the same, composites of functionalized multiwalled carbon nanotubes (f-MWCNTs) and ethylenediamine tetraacetic acid (EDTA), nitrilotriacetic acid trisodium salt monohydrate (NTAA Na3.H2O), and N-(2-Hydroxyethyl) ethylenediaminetriacetic acid trisodium salt hydrate (N-(2-C2H5O) ED(CH3COONa)3) were prepared and utilized for the surface modification of screen-printed carbon electrodes.
A systematic synthesis follow-up was achieved from the investigations on structural, morphological, optical, and electrochemical analysis of these interface materials. The electrochemical sensing characteristics of the surface modified electrodes were analyzed using Cyclic Voltammetry (CV) and Differential Pulse Voltammetry (DPV) techniques. The design parameters such as different loading volume, loading concentration, scan rate, pH, and accumulation time were optimized based on the systematic control studies.
The selective charge transfer characteristics of the developed sensors toward the target pesticides were decoded with the aid of electrochemical, optical, and DFT studies in-turn the electrochemical sensing mechanism. The developed sensors exhibited a wide linear window and lower detection limit for all the three pesticides (Imidacloprid: 0.001 nM-0.04 mM & 3.1×10-3 pM; Carbendazim: 0.5 nM-500 μM & 5.54 pM; Chlorpyrifos: 0.5 nM-500 μM & 9.7 pM) respectively.
Further, these sensors exhibited similar type of electrochemical behaviour as witnessed in the case of analytical standard compounds, which reveal the excellent recognition capacity over their respective active ingredients present in pesticide formulations. The observed repeatability, reproducibility, and stability of these sensors with low percentage deviations suggest their high performance metrics.
Moreover, the real-time performance of these sensors was investigated using samples collected along the Kaveri River and validated with High Performance Liquid Chromatography (HPLC) technique. All the three sensors showed excellent recoveries in the ranges of 93-107%, 93-110%, and 92-120% for imidacloprid, carbendazim, and chlorpyrifos, respectively. Thus, the sensors can be taken for deployment in water bodies for the selective real-time quantification of these pesticides
Effect of Laser Textured Surface with Different Patterns on Tribological Characteristics of Bearing Material
No full textThis research work determines the wear rate and friction characteristics of bearing material under different laser textured surface conditions. Chrome steels are used in bearings since they possess high strength and wear resistance. However, when those parts are in service, failure happens due to sliding friction before the lifetime. To improve the durability of the American Iron and Steel Institute (AISI) 52100 chromium steel, in this work, the effect of laser surface texturing (LST) was analysed.
With the different pattern of circle, ellipse, groove and grid were produced on the sample surface, the wear behavior was investigated using the pin on disc tribometer. The lubricant used for wear analysis is semisolid lithium grease National Lubricating Grease Institute Lubricant (SKF NLGI-3). Sliding wear analysis was conducted at different loads and sliding speeds. The wear morphology was analysed using a scanning electron microscope (SEM). The roughness of the samples was found using a white light interferometer.
In the first phase of work laser process parameters were identified and LST shows considerable reduction in friction and wear for ellipsoidal pattern than the other patterns because of wear debris and lubricant getting trapped. In the second phase of work though the best texture shape is obtained, further focus on the optimum texture size, depth, and texture density will improve the overall performance of the bearing material and the durability. In the final phase of work the identified texture shape and its geometry were further investigated to determine the suitable service conditions.
By varying the temperature, load and speed of the wear test parameters minimum and maximum wear rate was obtained. It is observed that the texture design fabricated on the bearing material have maximum wear resistance compared to untextured bearing material. This study is useful to design and fabricate laser textured surface on bearing which will improve its life and durability
Synergistic Approaches For Microstructural Refinement, Enhanced Mechanical And Wear Behaviour In Additively Manufactured 17-4 PH Stainless Steel
Get PDFThe surface and microstructural characteristics of additively manufactured parts play a significant role under mechanical loading. Due to its high strength, tailorable mechanical properties by heat treatment, and ease of printability, the 17-4 precipitation hardened (PH) stainless steel is gaining attention in the additive manufacturing (AM) field.
Selective Laser Melting (SLM), one of the laser-based powder bed fusion (L-PBF) processes, is capable of making fully dense metallic parts with high geometrical fidelity and greater design flexibility at high resolution. The main factors limiting the adoption of SLM are poor surface roughness, anisotropic microstructure, and the formation of micro-pores in the components. These issues lead to poor mechanical properties and eventual component failure.
In recent research, alongside heat treatment, peening technology is increasingly utilized to mitigate the adverse effects of SLM. This research presents an experimental investigation into the fabrication, characterization, and property enhancement of 17-4 PH SS fabricated by the SLM process.
The samples were printed at various laser energy densities (LEDs) in order to identify the optimum SLM process parameter combination, which results in superior mechanical properties. Mechanical tests, along with density measurements and surface morphology tests, were conducted to evaluate the performance of the as-printed (AP) samples. The results of the mechanical tests were then compared with those of the wrought sample.
In the final phase, the AP sample underwent a specific heat treatment (HT) process to introduce Cu-rich precipitates in its grain morphology, thereby enhancing its mechanical properties, including hardness and tensile strength.
LSP, considered one of the advanced surface modification techniques, was performed on both as-printed and heat-treated sample surfaces, and the combined effect of HT and LSP on the surface morphology, microstructure, residual stress, mechanical and high-temperature wear behaviour on the selective laser melted 17-4 PH stainless steel was evaluated
Identification of a Novel Target for Declustering Supernumerary Centrosomes in Triple Negative Breast Cancer
Get PDFTriple-negative breast cancer (TNBC) confers considerable interventional challenge owing to its massive heterogeneity, aggression and metastatic prowess. These facets are attributed to chromosomal instability (CIN), a feature consequent to TNBC cell’s ability to harbor more than two centrosomes (supernumerary centrosomes; SNCs).
In principle, if a normal cell possesses SNCs, uneven pull forces are generated consequent to multipolar spindle, which activates cellular surveillance. This ensures error-free mitosis by either repairing the error or, in an irreparable condition, driving cells to death. This averts the possibility of aneuploidy (fundamental to tumorigenesis).
Unfortunately, TNBC cells, despite harboring SNCs, have devised a survival strategy to overcome death by clustering their SNCs into two opposite poles via centrosome clustering (CC). This mimicry not only circumvents surveillance but also enables cancer cells to thrive unperturbed. Therefore, CC inhibition might be an effective strategy to selectively kill TNBC cells.
However, the precise molecular mechanism that allows CC is hitherto unknown, and exploring the same might provide an insight into novel cellular targets for disrupting CC in TNBC. Herein, we attempted to identify a novel cellular target that governs CC in TNBC. We modulated the histone acetyltransferase activity of cAMP response element binding protein-binding protein (CBP), as only a handful of articles discuss its contribution to CIN. Inhibition of CBP by C646 attenuated the expression of proteins involved in the canonical NF-κB pathway (such as IKKα/β/γ, RelA).
On RelA inhibition, we noticed suppression of survivin (a cancer-specific target) in TNBC cells. Moreover, survivin attenuation declustered SNCs and induced multipolarity, which pushed TNBC cells to apoptosis. These findings were validated using a direct inhibitor of survivin, YM-155. YM-155 could kill TNBC cells by inducing spindle aberrations. Hence, we established survivin as a novel (functional) target in regulation of CC in TNBC cells.
We also identified a novel indenone derivative (nID) that could modulate the RelA-survivin functional axis and subsequently inhibit CC by inducing chromosome misalignment. Furthermore, we unraveled that in context to CC, a positive feedback loop between survivin and KIFC1 promotes cohesion of SNCs. Holistically, our research highlights the critical role of survivin in orchestrating CC in TNBC
Consumption Of Over-The-Top (OTT) Media Streaming Services In Rural Tamil Nadu
Get PDFOver-the-top (OTT) Media Streaming Services are modern online entertainment services based on new media technologies. During the COVID-19 lockdowns, the OTT consumer base experienced exponential growth, especially in India. Currently, the Indian OTT industry is in its second growth phase, owing to increased consumption in rural India. The interests of rural consumers align with different types of OTT content, providing potential market for OTT media streaming services. Tamil Nadu is a front runner in the consumption of YouTube and other popular OTT media streaming services in the country. The Government of Tamil Nadu is making penetration efforts to establish OTT services in the rural parts of the state. There are OTT startups that are sprouting to curate only Tamil content. In addition, major portion of the population residing in the rural areas and the growing importance for the demand for regional content make Tamil Nadu as a market with huge potential. Considering all these advantageous trends, this study focusses on studying the OTT consumption status and consumer behaviour in rural Tamil Nadu.
The study aims to explore on the research questions to understand the socioeconomic characteristics and digital infrastructure accessibility that influence OTT consumption patterns among rural consumers. It aims to identify their content preferences and the gaps between desired and actual performance levels of OTT services. Additionally, the research examines the primary motives and gratifications driving OTT media consumption and their associated outcomes. The study also endeavours to develop a comprehensive model of OTT consumption outcomes tailored to the rural consumer market.
The research instrument was designed to assess the OTT consumption status by studying the socioeconomic characteristics, enablers of OTT media consumption, OTT consumption profile and pattern, OTT habitude, behavioural shift and preferences for different content. In the same way, the factors that influence the consumption outcomes were studied by developing a conceptual model by adopting the constructs of Uses & Gratification theory (UGT) and Uses & Gratifications 2.0. Purposive sampling was chosen for the study, encompassing 802 respondents across all 38 districts of Tamil Nadu.
Significant findings reveal that youngsters form the primary consuming class. The accessibility to OTT is decent but not exceptional. Consumers are receptive to freemium platforms that offer variety and they consume content with mobiles for 31 min - 1 hour/day on an average. They use bundled services and have different opinions on account sharing, and no penetration of audio/music streaming services and aggregators is observed. Consumers have different preferences for content and prefer to watch short content. Expectation vs. Reality gaps were observed in content and promotions, interface, and quality parameters. UGT motives such as relaxation, information seeking, easy navigation, and interactivity are high among respondents. Of all the consumption outcomes, WoM intention is high. Regarding Affinity, the influence of all the motives and new gratifications on Affinity were significant except Relaxation, Arousal, Social interaction, Pastime, Escape and Agency. Likewise, the influence of all the motives and new gratifications on intention to continue consumption were significant except Relaxation, Arousal, Social interaction, Pastime, Escape and
Agency. In the same way, the influence of all the motives and new gratifications on WoM Intention were significant except Relaxation, Social Interaction, Companionship and Interactivity. The research model was tested and found to have high relevance, explanatory and predictive power.
Based on the objectives of the study, the specific findings and their implications have been discussed. These results of the socioeconomic characteristics of the respondents imply that there is a need for better segmentation alongside the prevailing segmentation strategies (like socioeconomic segmentation) practised by marketers. These results assessing the enablers of OTT consumption imply that despite belonging to rural areas, they have access to digital communication technologies, and the basic minimum infrastructure for accessing OTT services is available among the respondents. The level of internet access of the respondents has implications for various stakeholders such as Governments, TSPs, ISPs, manufacturers of consumer electronics (media related) and OTT market players to work towards democratisation of the ICT. The OTT consumption patterns of the study provide several important implications for stakeholders, including smartphone manufacturers, mobile app designers, content producers, OTT market players, TSPs, ISPs, advertisers, audio streaming platforms and OTT aggregators in designing strategies to improve quality and reduce the cost of smartphones, creating more user-friendly mobile apps, producing mobile-friendly content, creative subscription plans and bundled services, strategic advertising and penetration efforts. These results of OTT habitude also provide implications for the marketers to work on content optimisation, personalisation, content rating and review mechanisms. These findings of the behavioural shift underscore the significance of OTT platforms as not just sources of entertainment but also as influencers of behaviour, suggesting a huge scope for consumer behaviour research and the impact of OTT consumption on the lives of consumers. One notable finding regarding the content preferences is that people prefer to watch the content of short duration. This trend is prevalent, especially after the advent of new media. The results of the gap analysis provide various implications on adopting strategies in the areas of content and promotions, interface usage and quality. The results of Motives and New Gratifications on the Consumption Outcomes signify a lot of theoretical and practical implications.
The suggestions of the relevant findings have been categorized based on the type of stakeholders. With regard to the findings of new gratifications, adoptable business, marketing, content strategies, strategies for partnerships for OTT service providers and startups have been suggested. Business strategies in order to improve MAIN features, maintaining balance in bundling, tapping the potential of audio streaming and aggregators, improving consumption, data management, managing content piracy have been suggested. In addition, marketing strategies like socioeconomic segmentation, life stage segmentation, advertising and strategic pricing have been discussed. Content strategies like content localisation and experimentation, optimization to enhance on-the-go consumption and innovative short content creation have been suggested. Suggestions for manufacturers of consumer electronics, developing secondary markets like the mobile accessories market, cross-platform partnerships, telecom service providers and DTH operators have been proposed for strategic partnerships. Suggestions have been proposed for the policymakers regarding ICT democratisation efforts, content regulation and Government-owned OTT platforms
Investigating the Fatigue Life of Asymmetric and Novel Helical Gear Drives
Get PDFThe present research work investigates the contact and bending fatigue life of asymmetric helical gear and novel helical gear based on the finite element analysis. In the first phase, the contact and bending fatigue life of the asymmetric helical gear drives is estimated based on the strain life approach.
Further, a parametric study is carried out to investigate the influence of important helical gear parameters such as module, pressure angle, helix angle, gear ratio, teeth number and face width on contact and bending fatigue life of asymmetric helical gear drives. It is noted that the asymmetric helical gear shows a significant improvement in contact and bending fatigue life compared to a symmetric helical gear.
In the second phase, an optimization of important asymmetric helical gear parameters is done to achieve an optimum contact and bending fatigue life. Also, a regression equation is formulated to determine the contact and bending fatigue life of asymmetric helical gear. In the final phase, the novel helical gear is designed by varying the rack cutter tooth thickness factor to achieve a balanced contact and bending fatigue life between the gear and pinion.
Further, the influence of important gear parameters on the contact and bending fatigue life of the novel helical gear drive is determined. It is observed that the contact and bending fatigue life is balanced between the gear and pinion by modifying the rack cutter tooth thickness factor. Finally, the comparative study on asymmetric helical gear and novel helical gear is carried out in terms of the fatigue life. This study will be useful for design and develop a non-standard helical gear drive with optimum fatigue life for customized high-power transmission
Mechanical Characterization of Hemp, Jute, and Flax based Natural fibre Composites for Non-structural applications in Aircraft and Automobiles
Get PDFDemand for reducing energy consumption and detrimental environmental impacts after the effective lifetime of an engineering material are the major driving factors for the development of natural fibre reinforced composites (NFRCs) in various sectors. Compared to synthetic fibre like carbon-fibres or Kevlar, natural fibres provide several benefits including light weight, inexpensive, recyclability, superior specific strength, biodegradable, non-toxic during handling, and less energy intensive during manufacturing. This doctoral work presents observations from mechanical tests and interpretations on the suitability of natural fibre reinforced composites for less heavily loaded engineering applications areas.
In the first stage, jute, flax, and hemp fibres were tested at single fibre, yarn, and fabric levels under ASTM standard tensile loading test conditions. Study results revealed that hemp fibres had superior strength among the three fibres. In the second stage, fibres were impregnated in the epoxy resin using hand layup method for the NFRC to have a specific weight fraction 45:55. Then samples for mechanical testing (tensile, flexural, and compression) were prepared following ASTM standards.
Prepared cut samples were undergone tensile, compressive, and 3-point bend tests using the Zwick Roell universal testing machine at PSGTECH Coe Indutech, Coimbatore. The results revealed that Jute fibre reinforced composite (JFRC) and Hemp fibre reinforced composite (HFRC) are better among the three based on observations in mechanical properties and most likely failure type based on scanning image microscopy.
In the third phase, the selected JFRC and HFRC were modelled and evaluated for fatigue loading conditions in a computational study with ANSYS. These test samples were also subjected to sound absorption test, and flammability test as per respective standards. Results showed HFRC to have superior fatigue response over JFRC.
The sound absorption ability of of both JFRC and HRFC were almost similar with a slightly better performance observed in JFRC, especially in high frequency range. Flammability test results showed that HFRC had higher resistance to flammability as compared to JFRC. This work observed at least one NFRC to have most of the desired properties in an engineering material to be considered for automotive or aerospace applications
Preventing Orthopedic Implant Associated Biofilm Infections Using Transition Metal Complex Laminated Bioactive Implants
No full textOrthopedic implants are medical devices employed to repair the damaged structure and function of an injured musculoskeletal system. It helps millions of people suffering from bone fractures and arthroplasty. The increased use of orthopedic implants has given rise to implant-associated biofilm infections. Biofilm-mediated Implant-associated osteomyelitis (IAO) is a major concern in the medical field, wherein the treatment involves debridement, administration of antibiotics and removal of implants leading to increased cost of treatment.
The keystone bacterial pathogens involved in orthopedic implant-associated infections are Staphylococcus aureus and Acinetobacter baumannii which are members of the ESKAPE pathogens. A. baumannii has gained resistance against almost all antibiotics and have become a keystone pathogen in the clinical sector. S. aureus is a notorious pathogen responsible for chronic implant-associated osteomyelitis which is found to be highly resistant to various drugs compared to S. aureus isolated from non-implant sites. To overcome antibiotic resistance and biofilms, a novel anti-virulent treatment measure for implant-mediated bone infection is the need of the hour. Attenuating biofilms and virulence factors is an effective approach to control chronic implant infections.
Therefore, in the current study, we focused on targeting the virulence and biofilms of A. baumannii and Methicillin-resistant Staphylococcus aureus using palladium(II) complex of NNN chelating thiazolinyl-picolinamide. Among different Pd(II) complexes, Pd(II)-E had potent biofilm inhibitory effects for both A. baumannii and MRSA. In addition, Pd(II)-E effectively mitigated quorum sensing mediated virulence factors of A. baumannii including pili motility and polysaccharide production. Pd(II)-E acts as a potent anti-virulent agent against MRSA by inhibiting slime synthesis, spreading motility, and staphyloxanthin pigment production. qPCR analysis further confirmed the downregulation of genes responsible for biofilms and virulence in both pathogens.
Since Pd(II)-E suppressed virulence and biofilms of keystone pathogens involved in orthopedic implant infections, Pd(II)-E was coated on titanium plates in view of fabricating anti-infective orthopedic implants. The efficacy of coated titanium plates in preventing dual-species biofilm infections was assessed. Pd(II)-E coated titanium plates showed remarkable alleviation against mono- and dual-species biofilms of MRSA and A. baumannii. The study also found that host protein binding factors of pathogens have a vital role in dual-species biofilm infections. The stability of the coated plates in artificial synovial fluid (ASF) was confirmed using EDAX analysis.
qPCR studies were performed between mono- and dual-species biofilms to identify interaction between dual-species biofilms. The effectiveness of Pd(II)-E coated plates was investigated at the molecular level using qPCR analysis for genes responsible for biofilms, quorum sensing, and host protein binding factors. The results revealed that Pd(II)-E coated plates downregulated the genes of the above-mentioned virulence of mono- and dual-species biofilms in ASF. Biocompatibility of the coated titanium plate was confirmed in human osteoblast cells. Taken together, we envision that Pd(II)-E coated titanium may act as a potent bioactive biomaterial to prevent orthopedic implant infection
Development of 3d Printed Anatomically Equivalent Thermoplastic Polyurethane Conduits for Peripheral Nerve Regeneration
No full textThree-dimensional (3D) printing is an emerging tool for creating patient-specific tissue constructs analogous to the native tissue microarchitecture. In this study, anatomically equivalent 3D nerve conduits were developed using thermoplastic polyurethane (TPU) by combining reverse engineering and material extrusion (i.e., fused deposition modelling) technique.
Printing parameters were optimized to fabricate nerve-equivalent TPU constructs. The TPU constructs printed with different infill densities supported the adhesion, proliferation, and gene expression of neuronal cells. Subcutaneous implantation of the TPU constructs for three months in rats showed neovascularization with negligible local tissue inflammatory reactions and was classified as a non-irritant biomaterial as per ISO 10993-6. To perform in vivo efficacy studies, nerve conduits equivalent to rat’s sciatic nerve were fabricated and bridged in a 10 mm sciatic nerve transection model.
After four months of implantation, the sensorimotor function and histological assessments revealed that the 3D printed TPU conduits promoted the regeneration in critical-sized peripheral nerve defects equivalent to autografts. This study proved that TPU-based 3D printed nerve guidance conduits can be created to replicate the complicated features of native nerve tissue that can promote the regeneration of peripheral nerve defects and also show the potential to be extended to several other tissues for regenerative medicine applications
PM2.5 In the Respirable Air a Threat to Heart Health Investigating the Influence on Cardiovascular Performance and Unmasking the Potential Strategies for Cardio Protection
No full textAir pollution, characterized by the presence of harmful substances in the atmosphere, represents a significant environmental and public health challenge impacting millions worldwide. The World Health Organization (WHO) reports that approximately 90% of the global population resides in regions where air pollution surpasses the recommended thresholds for healthy air quality. Within the realm of air pollution, the composition of particulate matter emerges as a pivotal consideration, particularly regarding PM2.5, comprising minute particles originating from diverse sources such as combustion processes, industrial operations, and natural phenomena like wildfires and dust storms. PM2.5 exhibit a range of chemical and physical attributes contingent upon their origins, thereby influencing their toxicity and potential health implications.
While extensive research has scrutinized the association between PM2.5 exposure and respiratory ailments such as chronic obstructive pulmonary disease and cancer, the cardiotoxicity of PM2.5 have frequently been overlooked, even with evidences linking exposure to elevated risks of cardiovascular diseases like atherosclerosis and myocardial infarction (MI). In addition to its cardiotoxic effects, PM2.5 has been implicated in vascular toxicity as well. Residents in regions with high PM2.5 levels, such as those proximate to major roadways or industrial hubs, face amplified risks of atherosclerosis or exacerbation of pre- existing calcification conditions.
Nonetheless, the precise role of PM2.5 in promoting and inducing calcification remains unresolved. PM2.5 induced alterations in myocardial basal levels may compromise its resilience against stress, impede adaptive mechanisms, and hinder reparative processes, culminating in severe cardiac complications. The perturbed blood circulation stemming from PM2.5 exposure precipitates ischemia, prompting the body\u27s efforts to alleviate blockages. Surgical interventions like Coronary Artery Bypass Grafting (CABG), angioplasty, or primary percutaneous coronary intervention (PPCI) may become necessary, leading to the risk of ischemia reperfusion injury (IR).
Furthermore, PM2.5 exposure increases the likelihood of MI occurrences and reducing the cardiac recovery post-MI. Even though there is an association between PM2.5 exposure and cardiac events such as IR and MI, the precise underlying mechanisms remain incompletely elucidated. Mitigating PM2.5-induced cardiotoxicity and enhancing myocardial resilience against stress necessitates the exploration of personalized protective measures and environmental pollution abatement strategies. Identifying suitable therapeutic agents to alleviate PM-induced cardiotoxicity and thereby increase the myocardial endurance against subsequent stress, including revascularization procedures, emerges as a critical imperative