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Development of Efficient Speckle Suppression Algorithms for SAR Images
No full textSynthetic aperture radar (SAR) is an active imaging sensor that provides highresolution, cloud-free images in varying illumination and weather conditions. SAR images have been used in a wide range of applications such as remote sensing, geology, environmental monitoring, and military surveillance. However, these images are inherently noisy due to the presence of granular structures known as speckle. Its presence visually degrades the underlying image information and has an impact on subsequent image analysis. The amplitude based noisy SAR image follows Rayleigh statistics. This dissertation focuses on the development of efficient algorithms for speckle suppression in SAR images using variational methods. Among various speckle reduction filters, the variational methods restore the clean image by minimizing a suitable cost function. This function consists of a forward/data model derived from the speckle statistics and a prior/regularization model containing the information regarding the image. The minimization is carried out using a suitable optimization technique. Developing an effective prior is a non-trivial task, and the utilization of complex priors makes the optimization problem difficult to solve. The plug-and-play (PnP) is a flexible framework that substitutes priors with state-of-the-art denoisers and thereby simplifying the software integration. Further, it can be easily solved by adopting any appropriate splitting techniques, such as alternating direction method of multipliers (ADMM). The first contribution includes the continuation scheme of PnP ADMM for the reduction of Rayleigh based speckle in SAR images. The forward model is coupled with the standard denoisers, and the optimization problem is solved using ADMM. Though this technique shows good despeckling performance, it has no clearly defined cost function. This difficulty is addressed in the second contribution by utilizing regularization by denoising (RED), a framework closely associated with PnP. It defines an explicit prior using denoisers and has simple gradient expression. The data model is derived in the homomorphic domain. The cost function is devised by combining the data model with the RED prior and is solved using ADMM. Although the proposed technique increases despeckling accuracy, it has certain limitations. It imposes several constraints on denoisers, hence the benefits of the majority of denoisers cannot be realized. The third contribution is based on the actual priors that overcomes the problems associated with denoiser-induced priors. Specifically, the fractional order total variation (FrTV) Abstract prior and a non-convex penalty function are employed to preserve image features, avoid artifacts, and promote sparsity. The multiplicative noise model is converted to an additive model using suitable modifications. The cost function is constructed by combining the data term for the additive model with the aforementioned prior and penalty in the wavelet domain. The resulting optimization problem is solved using the well-known ADMM algorithm. It exhibits improved despeckling performance, but generates strip artifacts in practical SAR images. It is always a difficult task to choose an appropriate prior for regularized inversion problems. The fourth contribution exploits the benefits of nonlocal self similarity (NSS) and uses the dictionary based sparse framework to suppress the speckle noise. Specifically, the proposed sparse representation framework addresses the despeckling task by formulating an optimization problem. It consists of the data model derived in the multiplicative noise domain, an ℓ1−norm prior (sparse coefficients), and a penalty term that is based on the difference between the extracted patch and its corresponding sparse representation. It is solved by alternatively updating the dictionary, sparse coefficients, and the latent image. The simulations are carried out for both simulated and practical SAR images. The proposed algorithms are compared with several methods by computing the reference, without-reference, and edge-preserving measures. The despeckled and ratio images are visually compared for subjective evaluation. The fixed-point convergence analysis is carried out for the PnP-based method. Likewise, the residual convergence analysis is conducted for the RED- and FrTV-based algorithms. The merits and drawbacks of each strategy are discussed thoroughly in this research
Rotordynamics of High-Speed Rotors Supported on Gas Foil Bearings
No full textHigh-speed rotor-bearing systems have received significant interest in the field of rotordynamics and vibration analysis. These systems are used in a wide range of turbomachinery applications such as turboexpanders, turbo compressors, turbo generators, turbochargers, etc. Due to the high speed, these machines are susceptible to rigorous vibration and instability. These instabilities can be addressed by the design of a suitable rotor and its supporting bearings. In many cases, such systems need oil-free bearing technology to address the issues of contamination and high friction. One of the suitable approaches to overcome these limitations is to use gas bearings. These bearings have become increasingly popular over the last few decades due to their advantages, such as low frictional losses, low power consumption, the ability to operate at high temperatures, and low noise. However, a downside of simple gas bearings is that they have low stiffness and damping properties. Therefore, gas foil bearings have been proved to be an appropriate candidate for such a high-speed system due to their compliant behavior and higher load-carrying capacity. In the present work, a numerical model of the gas foil bearing is developed by utilizing the perturbation approach to predict the stiffness and damping coefficients of bearings. The behavior of the normalized stiffness and damping is obtained with respect to the bearing number and compliance number. The results are utilized, and Sobol's sensitivity test is conducted to estimate the most effective parameters among the length-to-diameter ratio, eccentricity ratio, bearing number, whirl ratio, and compliance number. After that, the characteristic data sets obtained from the analysis are used to train an artificial neural network (ANN) for a wide range of bearing parameters. Additionally, an adaptive neuro fuzzy interface system (ANFIS) is established to determine the optimum range of data for which maximum stiffness and damping can be obtained. In the next phase of research, the modal behavior of a high-speed rotor-bearing system is estimated for a turboexpander. The finite element (FE) modeling of the high-speed rotor is carried out, which takes into account the gyroscopic effect, shear deformation, internal damping, inertia of the rotor, and the dynamic coefficients of the gas foil bearing. Further, the thesis attempts to reduce the finite element model by gradually discarding the rotational as well as translational displacements for the rotor and investigating its effect on the response of the rotor while maintaining a tradeoff between the accuracy and computational time of the reduced models. A set of recommendations are suggested for careful selection of the degrees of freedom at important locations, which influence the reduction success chances. The reductions are applied to the high-speed rotor-bearing model, and a comparative analysis was presented via four robust model reduction techniques: Guyan, improved reduced system (IRS), component mode synthesis (CMS), and modified system equivalent reduction expansion process (Modified SEREP). Additionally, a novel meta-modeling approach is suggested where a neural network model is developed for multi-level response prediction. The implementation of artificial intelligence in rotordynamics is absolutely important as is that it enables data-driven meta-modeling. This technique incorporates unpredictability and randomness which are necessary for the response variation analysis of rotating systems. In this meta-model, a large number of low-fidelity data from the reduction model and a limited number of high-fidelity data from the FE model are used. The performance of the model is demonstrated by employing frequency response characterization of the high-speed rotor-bearing system. Further, the experimental investigation is presented in the current dissertation to study the vibrational behavior of the high-speed rotor supported on gas foil bearings. The fabrication methodology of the rotor, gas foil bearings, housing, and all the associated parts of a turboexpander is presented. The rotor is dynamically balanced, and all the components are assembled. Additionally, the test setup is also developed to test the performance of the high-speed rotor. The high-speed rotor-bearing system is attached to the DAQ (data acquisition system) and vibration card. The various sensors and equipment like an oscilloscope, proximity probes, piezoelectric accelerometers, a digital tachometer, and a high-pressure compressor air facility are used to fully develop the experimental test facility. The feasibility study was performed based on a comparison of rotordynamic analysis and experimental data for the critical speed of the rotor and unbalance response at bearing locations. Overall, the thesis highlights the importance of using a model reduction method and artificial neural network instead of using only a FE method to predict the rotordynamics of the high-speed rotor-bearing system. For the gas foil bearing design, the most influential parameters are identified, and the range of these parameters for maximum stiffness and damping are determined. The results also conclude that the classical recurrent neural network underestimates the frequency response of high-speed rotor-bearing systems, and thus, a multi-fidelity neural network should be used for prediction. Finally, the experimental investigation is carried out to validate the numerical models formulated in the thesis
Mathematical and Experimental Studies of Evacuated Tube Solar Dryer for Drying High Value Medicinal Herbs
No full textMedicinal plants are a potential source of bio-molecules that play a major role in modern medicines in the treatment of diseases like cancer, diabetes, hypertension, etc. Owing to poor harvest losses of the herbs, spoilage and quality degradation occur. In order to preserve herbs for a longer duration and make them more readily available during the off-season, an appropriate drying method is essential for the removal of moisture. The drying sector consumes more energy, and the energy required for drying should be used without depleting fossil fuels. Therefore, it is necessary to apply the right drying technology to reduce losses and maintain product quality. Solar energy is an alternative to drying medicinal herbs. Therefore, drying food products using solar energy is beneficial in terms of energy and environmental concerns. In this regard, there is a need for the development of a novel and economical solar dryer for quality drying of medicinal herbs. This research work aims to examine drying of three medicinal herbs available in India using an evacuated tube solar dryer. The research work comprises five components; (i) fabrication and investigation of solar air heater for drying application (ii) studies on drying characteristics of medicinal herbs (iii) thin-layer modelling of three medicinal herbs (iv) characterization of dried leaves and quality analysis and (v) 4-E (energy, exergy, environmental and economic analyses). In this research work, as a first step, a preliminary study was carried out on design, fabrication, and testing of an evacuated tube U-type solar collector. The fabricated collector was capable of producing a temperature range of 70-80ºC at the ETSC outlet. So, the developed U-type with ETSC can be useful for medium-temperature industrial process heating applications. As a second step, the research study aimed to dry three potentially available medicinal herbs in India using an ETSC dryer. It briefly described the significance of medicinal herbs, namely neem leaves, Krishna tulsi leaves, and Ashwagandha roots. It also explained the importance of drying these herbs, and sample preparation for drying experiments was also explained. When performing solar drying experiments, continuous measurements of various parameters like solar radiation, relative humidity, velocity, temperature of the air at different locations, and weight of the samples were required. Therefore, different measuring instruments required for exploring a product's drying behaviour were presented, along with their technical specifications. The ETSC dryer reduces the initial moisture content of neem leaves from % (db) to 8.34% (db) in 7 hours, whereas it takes 13 hours in the OSD. The average drying rate in ETSC and OSD processes is 0.004 and 0.0023 % db min-1, respectively. After conducting the drying experiments, as a third step, thin-layer mathematical modelling of herbs carried out using the curve-fitting tool in the MATLAB software to predict the moisture ratio from the obtained experimental data was explained. Moisture ratio expression models were used from the literature and applied to find the best model for determining drying data in the ETSC and OSD modes. The Verma et al., model is the most suitable for the drying of neem leaves in ETSC drying mode with a R2 of 0.9994 and RMSE value of 0.01002. In the OSD experiment, the Modified Henderson and Pabis model is found to be the best fit with a R2 of 0.9984 and an RMSE value of 0.0153. In order to understand the product’s microstructure, and the presence of different bonds, dry leaves must be characterized. Therefore, the results pertaining to the characterization of dried samples were done using a scanning electron microscope (SEM), X-ray diffraction (XRD) analysis, and Fourier transform infrared (FTIR) spectroscopy. Further, the quality analysis of the dried samples was done using color analysis and total phenolic content (TPC). Folic-Ciocalteu method was used to find the TPC of the dried samples. For neem leaves, TPC values in ETSC and OSD are found to be 95±2.4 mg in GAE/gr sample and 36±1.68 mg in GAE/gr sample, respectively. For Krishna tulsi, TPC values are found 7.28±1.8 and 4.97±1.1 for ETSC and OSD, respectively. For the dried Ashwagandha roots, TPC values are found as 32.35±1.4 and 21±2.1 for ETSC and solar dried samples. As a last step, energy, and exergy analyses were carried out for the proposed dryer when drying three medicinal herbs along with sustainability indices of the drying system. In addition, environmental and economic analyses of the developed dryer were estimated and presented for the selected dried herbs. The embodied energy of the fabricated ETSC dryer is 349.874 kWh. For the dryer’s anticipated 20-year lifespan, CO2 mitigation and earned carbon credit values are 13.2 tonnes and INR 10894 to 43576, respectively. All the proposed objectives have been achieved and the proposed dryer is suitable for drying medicinal herbs of high quality and will be beneficial for the medium and small scale entrepreneurs
Design and Development of Desheller cum Pulper for Wood Apple Fruit (Limonia acidissima) and By-product Utilization of Shell
No full textThe wood apple fruits (Limonia acidissima) belonging to the family “Rutaceae” has extensive phytochemical and nutraceutical composition contributing to various health benefits. The wood apple fruit is a “Minor Forest product” native to India and Sri Lanka. The post-harvest processing of the whole wood apple fruit is essential for utilization of fruit pulp and development of value-added products. However, due to the lack of proper process technology, the fruit is currently processed by traditional manual operations using hammer or stone for breaking the fruit and spoon for scooping the pulp. The existing manual process is laborious, tedious, time consuming, causes contamination, wastage and can lead the product to be unsuitable for development of value-added products. Hence, this urges the need to develop an equipment and process technology for wood apple fruits to reduce these traditional process problems and drudgery. The continuous-automated equipment of wood apple fruits for deshelling, pulping and seed removal were designed, developed and evaluated for optimum utilization of fruits. The engineering properties of the fruits were analyzed for design and development of equipment. The average mass of the fruits was 232 g and the maximum dimensions of the fruits were 8.86, 8.42 and 8.21 cm for longitudinal axis (LD), intermediate axis (ID), and short dimensional axis (SD), respectively. The wood apple desheller cum pulper equipment was designed using Creo elements V5.0 software that will be suitable for all sizes of the fruit. The equipment was fabricated with stainless steel (SS304) for fruit contact parts and mild steel for the support structure of the equipment. The developed equipment consists of cutting unit, conveyor with cups, pulping unit, deshelling unit and seed removal unit. The cutting units cuts the fruit into two halves that is transported by the conveyor cups to the pulping unit by limit switch, PLA sensors and sequential timer arrangements that permit the conveyor cups to stop at accurate location. The pulp in the shell is loosened and conveyed by gravity to the desheller that separates shell from the pulp fraction. The seed removal unit separates the seeds from one end and the pure pulp from the outlet chute. The performance of the equipment was evaluated and optimized. The optimum deshelling efficiency (98.9 %), pulping efficiency (85.8 %), pulp yield (35.97 %), overall effective throughput capacity (29.6 kg/hr) and minimum overall equipment loss (10.5 %) were achieved with 600 rpm vibratory screen speed and 16.3 rpm of seed removal unit screw speed. The overall throughput capacity of equipment was 83 kg/h. The cost-economic analysis of equipment was performed and found to be ₹ 1,60,000 (per unit) for fabrication. Additionally, the cost of processing to produce 1 kg of pulp is ₹ 103.4, break-even point is 2214 kg, and the pay-back period will be 0.5 years which suggested the economic feasibility for utilization of the equipment. The by-product of wood apple fruit, the wood apple shell has revealed to have various groups of functional compounds such as polyphenols, flavonoids, minerals, protein and antioxidant property from the chemical and phytochemical analyses. However, utilization of the shell in food formulations has seen limited applications due to lack of proper process methodology and value addition methods. Hence, this necessitates the development of a process methodology for optimum utilization and application of the bioactive compounds from the wood apple shell in food formulations. In the current work, the bioactive compounds from the wood apple shell were extracted using specific and combined cold-plasma ultrasound assisted extraction and the obtained shell extract was incorporated as a natural antioxidant in edible oil by emulsification (water-in-oil and oil-in-water emulsion) with encapsulation of oil-in-water emulsion by spray drying, as oil is prone to rancidity and as there is consumer resistance against the use of synthetic antioxidants. The cold plasma treatment (20 min time, 15 KV voltage) prior to ultrasound-assisted extraction (15 min time, 50% amplitude, 5 feed/solvent ratio) has significantly higher enhancement of antioxidant activity (90 DPPH% and 93 ABTS%), phenols (63.84 mg GAE/g DW), and flavonoids (6.03 mg Quercetin/g DW) content compared to specific extraction techniques. The Fourier transform infrared spectroscopy and Gas chromatography-mass spectroscopy of shell extract has confirmed the various polyphenols and antioxidant compounds. The shell extract incorporated in sunflower oil by water-in-oil emulsion at varied shell extract concentrations (0.5 & 1 %) and oil (70 to 90 %) has observed efficient results at 0.5 % extract and 80 % oil concentration at 4°C than 25°C temperature during 28 days storage with lower mean particle size, homogeneous narrow distribution of particles and no observation of creaming, oxidation stability, and has high viscosity. Whereas the oil-in water emulsions at core concentration of extract (0.5&1 %) and sunflower oil (10 to 30 %) have shear-thickening behaviour, homogeneous nano particle size with stable formulation exhibiting efficient results at 1 % extract with 10 % oil concentration co-encapsulated with greater oxidative stability of PV ≤10 meq O2/kg oil throughout 28 days with encapsulation efficiency of 88.6 %. The current study suggests that the wood apple desheller cum pulper is economically feasible and can be commercially utilized by rural, small and medium scale industries for development of value-added products. Additionally, the shell extract can be acceptable as a natural antioxidant replacing synthetic antioxidant and the co-encapsulates developed can be utilized as functional ingredients in food, pharmaceutical and cosmetic formulations
Analysis of RNA Population in Goat Spermatozoa.
No full textWhole transcriptome studies in humans, rodents, and livestock species such as cattle, pigs, and horses have shown the presence of both coding and non-coding RNAs in spermatozoa. However, a detailed analysis of the spermatozoal RNA (spRNA) population in goats and their relevance to sperm functions, such as motility and capacitation, is lacking in the literature. This study investigated the RNA population in goat spermatozoa by RLM-RACE, long-read NanoporeTM sequencing, and short-read IlluminaTM sequencing. The effects of heparin- and arginine-induced sperm capacitation and motility enhancement on spRNAs were also investigated. Results showed that motile spermatozoa can be best recovered (89.20±1.15%) by the Swim-up method and could maintain sperm motility (82.33±1.53%), viability (88.10±5.03%), and plasma membrane integrity (71.33±4.51%) in sperm TALP (Sp-TL) medium for at least 1 h. Treatment of sperm samples with 0.5% (v:v) Triton-X and 0.1% (v:v) sodium dodecyl sulfate completely removed the contamination of somatic cells, as revealed by negative expression of PTPRC and positive expression of PRM1 and PRM2 upon reverse-transcriptase polymerase chain reaction (RT-PCR). The goat spermatozoa were found to contain 20.03±0.47 fg of RNA per cell. The addition of dithiothreitol (DTT) as a reducing agent (20 mM) to the monophasic solution of GITC and phenol increased the yield of large-sized RNA (3.89±0.46 ng/million cells) suitable for long-read RNA sequencing (RNA-seq) of poly(A) transcripts. NanoporeTM sequencing resulted in reads ranging from 500bp to 2Kb in length that could be mapped to 123 transcripts by de novo assembly. On the other hand, full-length cDNA cloning by RLM-RACE identified 31 transcripts. The full-length transcripts of five fertility-related genes (AR, CATSPER3, DAZL, HSP90AA1, SPACA1, PRM3) were found in the goat spermatozoa. The short-read RNA-seq IlluminaTM discovered 16,604 transcripts that included mRNA (92%), lncRNA (4%), rRNA (2%), circRNA (1%), miRNA (1%), etc. A total of 357 mRNAs had FPKM of more than five. The goat spRNA population was also predicted to have 127 circRNAs, 655 lncRNAs, and 160 imprinted genes. The coding mRNAs were involved in different biological pathways, viz. Wnt signaling, cAMP-signaling, AMPK signaling, and MAPK signaling pathways. Results further showed that heparin-induced capacitation upregulated 1,251 transcripts and included PRND, LLCFC1, and SPESP1 genes that are known to participate in signaling pathways of sperm capacitation and acrosome reaction. Similarly, arginine-induced sperm capacitation and motility enhancement were also associated with the upregulation of 1,309 genes. The differentially expressed genes (DEGs) in both the heparin- and the arginine-treated group had upregulated genes involved in cAMP/PKA signaling, PI3-Akt signaling, MAPK signaling, calcium signaling, and oxidative stress pathways. DCFDA staining confirmed the increased generation of reactive oxygen species (ROS) in goat spermatozoa treated with heparin or arginine. In conclusion, this study documents the suite of RNA populations in goat spermatozoa and their relevance to heparin- and arginine-induced sperm capacitation. A molecular mechanism of heparin- and arginine-mediated sperm capacitation is proposed. This is the first report on RNA-seq of goat spermatozoa and their relevance to sperm function. Future studies should determine the existence of de novo transcriptional activities in goat spermatozoa during in vitro capacitation
Impact of Talent Agility on Innovation Adoption and Sustainable Business Performance: A Study of Indian Automobile Industry
No full textThe business world has gone through a systematic phase of rapid industrial revolutions. The emergence of industry 4.0 (I4.0) has created a storm in the global market through smart factory, smart manufacturing, IoT, cloud-based manufacturing (C-BM), cyber-physical production systems, smart HR 4.0 and many more. However, the Indian automobile industries are expected to undergo a dramatic transformation in I4.0. The automobile industry is the spearhead of Indian manufacturing sector, having a high growth rate, generating more employment, revenue, and profit. It provides employment to over 35 million people and contributes 7.1 percent of GDP. However, it has been seen that the emerging technologies of I4.0 have been successfully implemented in countries like USA, UK, and Japan. Whereas the concept of I4.0 is still in the nascent stage in India. The problem of dealing with the rapid technological changes, handling unpredictable and disruptive environments has been a pressing concern for both academia and industry. Talent agility becomes a strategic imperative for organizations in the digital and globalized business environment with fast-changing customer preferences. It can be defined as developing employees to adapt and evolve with change, provide innovative solutions, and quickly turn around and exhibit skills as the situation prevails. Therefore, developing in-house agile talent is a crucial element in a highly competitive environment, wherein employees can be trained to deal with complexity and ambiguity. Previously, talent agility was studied as an important concern for diversified sectors. Though talent agility is studied in different perspectives, it lacks empirical evidence in the context of innovation adoption with special application to the Indian automobile industries. Thus, the study attempts to conduct empirical research on the key enablers of talent agility, linking with innovation adoption and sustainable business performance in the Indian automobile industry. A survey questionnaire was administered among the middle level and senior level managers of the four wheelers passenger vehicle manufacturing plant in India. Data analysis is carried out using SPSS 24.0 for descriptive statistics. AMOS 26.0 is used to check the fitness of the proposed hypothetical model. Results indicate that climate for innovation, knowledge management, internal corporate communication, learning agility, and are positively associated with innovation adoption. Perceived innovation characteristics are also positively associated with innovation adoption and sustainable business performance. Further, innovation adoption is positively associated with sustainable business performance. However, ambidextrous leadership has a non- significant relationship with innovation adoption. This study will help the automobile practitioners and researchers in understanding talent agility knowledge area to make workforce readily available for the current wave of digital disruptions. This study provides a holistic framework of talent agility and innovation adoption that may act as a blueprint for the Indian automobile industry to attain sustainable business performance in the era of Industry 4.0
Salmonella Infection and its Impact on Caenorhabditis Elegans Development
No full textSalmonella infection is known to cause various developmental defects in humans including still birth, abortion and delayed development. Also this pathogen causes 50% reduction in the lifespan of Caenorhabditis elegans (C. elegans). But the mechanism behind this reduction is not explained well. The current study aims to find out Salmonella infection mediated defects in C. elegans, and the etiology behind these defects by checking all life stages of worm sequentially for any defects caused by the microbe and also extending the infection to subsequent worm generations in order to observe the magnitude of infection. During the investigation, the study encompasses Salmonella infection mediated egg retention in the worm that leads to various developmental and morphological defects leading to disruption of temporal regulation of developmental timing in C. elegans. S. Typhimurium is not entering the worm either through the egg surface or able to pass on to the next generation. Still, it enters normally through the oral route as worms eat bacteria. The microbe’s virulence factors or effectors and its pathogenesis are transferred to the next generation directly or indirectly as an outcome of infection. Progeny of infected worms hasn’t shown alteration in the percentage of males and hermaphrodites, while the infected worm population exhibits reduced copulatory events. Thus, Salmonella infection modulates the reproductive behavior and hence reduced brood size in the C. elegans. Worm’s delayed egg-laying response to Salmonella infection causes several defects in eggs, including over-folding of developing embryo, increased egg size, and eggshell defect, possibly in the fifth layer causing it to lose the osmotic stress tolerance and observed penetration of hydrophobic dye inside the worm’s egg. The egg-laying/retention defects might be due to the S. Typhimurium virulence factors affecting the worm’s nervous system, mostly the neurotransmitter FMRF amide encoded by the flp-1 gene, which was found upregulated in the case of infected worms. Two different transgenic worms flp-1(ok2811) and flp-1(yn2) with single and two gene knockout respectively, show reduced egg laying, which supports the alteration found in flp-1 and daf-10 genes during infection-mediated egg-laying defects. The downregulated daf-10 (required for the production of chemosensory amphid and phasmid sensilla) and cat-4 (encoding dopamine and serotonin precursor) indicate their role along with flp-1 for egg retention in infected worms. Also, the infected eggs have shown delayed hatching. The reduced chitinase activity in infected worms indicated reduced hatching and caused a significant number of dead embryos and a reduced L1 population. Salmonella infection also affects cell division polarity as it alters par genes which have a role in embryonic development, showing expression with upregulated par-3 while downregulated par-5 and par-6 expression. With Salmonella infection, significant upregulation of the heterochronic gene, line-28a, in the L1 stage and downregulation in the L2 larval stage along with other L2 stage-specific collagen genes col-72 and col-87 were found, and a disrupted L2 stage in the worm was also observed. But, surprisingly L3, L4, and adult developmental stages of the worm reached earlier in the infection cases. The precocious development of L3, L4, and the adult developmental stage is associated with Salmonella infection-mediated alteration in the stage specific genes important for the development of the worm. The important stage-specific genes rnh-1.3, col-158 and col-176 (L3); col-17, col-38 and col-49 (L4); and col-19 and col-7 (adult stage) were altered. The expression of hbl-1, a hunchback ortholog in C. elegans, which controls temporal development, and heterochronic genes like lin-14 were downregulated in the L2 stage while lin-42 and daf-12 were upregulated at the L3 stage, which suggests the precocious L3 stage development. Further, the early commencement of L4 and adult stages due to infection were examined through microscopy and altered vulva as well as gonad morphology were detected at these particular stages of the worm. Salmonella infection altering vulval morphology might implicate reduced egg-laying in the worm. The downregulated gonad migration genes (mig-6, mig-17, and mig-23) in L2 and L3 and upregulated in L4 indicate a disparity in gonad development in these stages. The heterochronic genes specific for L4 (lin-41) and adult stage (lin-29) are in congruence with the precocious development of these stages. Also, the downregulated tubular lysosomal genes in L2 to adult stage worms indicate their precocious development. Salmonella infection causes fewer adults and more undeveloped larvae. When the bacterial factors causing the significant alteration in the worm development, were analysed hilA, the master regulator of SPI-1virulence genes loci, was hypothesised to produce the virulence factor or effectors that can induce the defects at various stages as the hilA, SPI-1 and SPI-1,2 mutant was compromised in showing the defects. The similar phenotypes were observed in multiple generations also, but the impact reduced beyond F5 and F6. Overall the study shows that the Salmonella infection causes a range of developmental anomalies and results in the shortening of worm life span through various regulatory genes alteration, and the effect can be seen in subsequent generations also
A Study on the Structural Characteristics of North Indian Ocean Tropical Cyclones during 2001-2020
No full textThe tropical cyclones (or TCs) being one of the most extreme weather events, have the potential to cause catastrophic destruction to both human lives and properties. Its life span generally extends from a few days to weeks and the destruction caused by its combined effect of duration and size is incomparable to any other forms of atmospheric disturbances. Recent findings have suggested the rise in intensified TCs and their structural modulation in the global ocean basins like North Atlantic (NA) and western North Pacific (WNP). Over the North Indian Ocean (NIO) basin, several observational and modeling studies have been carried out during past three decades, which included the climatological aspects. However, the structural characteristics involving TC size, radial parameters, vertical structure, and associated environmental conditions have not been emphasized extensively. To address the said aspect, the present study emphasizes upon the estimation and distribution of TC size, radial parameters, and related meteorological factors, by using the scatterometer observations, global analyses, IMD (India Meteorological Department) and JTWC (Joint Typhoon Warning Centre) best track records, besides other relevant data sets. Also, the study adopted Weather Research and Forecasting (WRF) modeling system and the three dimensional variational data assimilation technique through WRF-DA to understand the impact of scatterometer winds on the structural characteristics. The study period is constrained to 2001-2020, based on the availability of the scatterometer data sets at the time of execution of the work. Accordingly, observational studies considered 71 TCs, whereas the modeling study considered 67 cases. This study analyzes the mean annual variations of TC size and radial parameters in the NIO basin, measured in terms of the radius of closed isobars (ROCI), Rvor (i.e. radius of 1×10-5 s-1 contour), radius of maximum winds (Rmax) and critical wind radii of 34 (R34), 50 (R50), and 64 (R64) knots (1 knot = 0.514444 ms-1) wind, computed following the vorticity based approach. The results presented in this work indicate that the error between TC centers determined by the vorticity-based approach and IMD data is in the range of 30– 105 km (mean value is 76.34 km) and with JTWC, the range is within 25–115 km (mean value 79.77 km) when all of the observations are considered. However, if the observations with the smallest time gap of 0.5) demonstrates that the new method effectively reduced the estimation error of Rmax. Also, the simulated vertical structures of the TCs are also analyzed. For this purpose, the cross sectional illustrations of relevant parameters are taken into consideration
Study of The Nanostructured Surface of Insect Wing for Fabrication of Novel Bioinspired Materials Having Bactericidal and Wound Healing Property
No full textAntibiotic resistance has become a global threat due to the high mutation rate in genetic materials of the different bacterial strains. To solve this problem antibacterial surface of the insect wing is emerging as a novel material for the development of nanostructured surfaces for medical devices. In this work, the surface profile of Cryptotermes brevis and Rhyothemis variegata wing were studied. The wing architecture is an inspiration to fabricate novel materials with exquisite properties. This study characterizes the structure and biological function of a wing. The topography of the surface of the wing was studied by electron microscopy and surface profilometer. The physicochemical property of the surface was analyzed by Fourier transform infrared spectroscopy, X-ray diffraction spectroscopy, energy-dispersive X-ray spectroscopy, and gas chromatography-mass spectrometry analysis of the epicuticle content. Water Contact Angle measurement confirmed the hydrophobicity of the wing surface. When microorganisms come in contact with the surface of the wing, they adhere to the wing surface due to cell surface properties of their own and the surface chemistry of the wing. This study reported the adhesion behavior of different bacterial species. The bactericidal activity of the wing was confirmed by counting the bacterial cell viability and examination under a confocal laser scanning microscope. Adhesion of bacteria was observed under the electron microscope. Bacterial oxidative stress, the topography of the wing, and the surface chemistry of the wing are the crucial factors that induce bactericidal activity. The roughness of the surface, nano-architecture, and chemical organization all are vital factors that prevent bacterial colonization at the surface of the wing. This work attempted to establish the correlation between nanostructure and bactericidal activity of the surface of the wing. The chemical organization of wing and surface topography both factor synergistically regulate the bacterial death that is examined under different microscopy. This work gives a basic idea about designing multifunctional surfaces by mimicking the surface of the wing. With these findings, chitosan-based material is fabricated which mimics the surface composition of insect wings. The combination of chitosan, stearic acid, and sesame oil provides us with a gel-like preparation that has high bactericidal activity and wound healing potential
Novel Mesoporous Zeolites from Industrial Solid Wastes for Remediation of Textile Wastewater
No full textEver-increasing population and industrialization directly influence air, soil, and water. Coal fly ash (CFA) and Red mud (RM) are significant inorganic wastes that take a large area of land for their disposal. Since water pollution and waste disposal play a vital role in affecting human beings and the environmental system, the merits of this waste are that it contains silicon and aluminum element, which is suitable for synthesizing versatile nano zeolite. This study mainly focuses on fabricating ETL structure type novel EU-12 nanosized mesoporous zeolite from CFA by sonication-assisted hydrothermal treatment method (SAH). CFA and the produced EU-12 nano zeolite were characterized by XRD, FESEM, EDS, XRF, TEM, RAMAN, DSC-TGA, BET surface area measurements, XPS, and zeta potential analysis for the first time. Sonication-assisted hydrothermal treatment method produced EU-12 nano zeolite in less crystallization time than the hydrothermal treatment method. TEM was used to identify the particle size of EU-12 nano zeolite in the range of 5 to 200 nm. Crystallinity % of EU-12 was obtained by analyzing XRD peaks as 76.39%. The optimized condition for EU-12 nano zeolite synthesis was: calcination temperature 850 °C, FA/NaOH 1:8, sonication time 30 min, hydrothermal treatment time 8 hours at 100 °C. The discharge of wastewater, mainly dyes, from various industries is a major problem of the present period because of its carcinogenic and other chronic effects. Therefore, transition metal sulfide loaded EU-12 coal fly ash-based nano zeolite photocatalysts were synthesized by the sono-hydrothermal method followed by ion exchange with seven different transition metal sulfides. The band gap of all synthesized photocatalysts was found to be ≤ 3.44 eV. Furthermore, the efficiency of synthesized zeolite and photocatalysts were determined in terms of adsorption efficiency towards cationic dyes such as Crystal violet (CV), Rhodamine B (RhB), and Methylene Blue (MB). Due to high adsorption efficiency and morphological properties, we propose that the synthesized nano zeolite can play a significant role as a low cost adsorbent in the remediation of toxic industrial dyes. The photoactivity of the photocatalysts was examined by degrading rhodamine b. The results indicated that transition metal sulfide/EU-12 photocatalysts had strong photoactivity under visible light compared to a dark environment. Furthermore, the efficiency of photocatalysts was determined in terms of degradation efficiency towards RhB, which was found to be a maximum of 98.62% for 0.2M CdS/EU-12 at 2 gL-1 of catalyst dose and 10 mg/l of dye concentration in 3 hours under a visible light source of 200 W. Magnetic Zeolite 4A was synthesized by the co-precipitation method and was used for cationic dye adsorption (RhB, MB, CV). The results indicated that magnetic zeolite had strong adsorption ability, easy to separate magnetic zeolite catalyst from the aqueous medium, and is reusable. The kinetics, adsorption isotherm, and thermodynamics were also studied for CdS/EU-12 photocatalyst. The study opens the possibility of scaling up the methodology for simultaneous recycling, recusing solid waste, and treating toxic dye