GCCP - NS: Grid based Congestion Control protocol with N-Sinks in a Wireless Sensor Network

Wireless Sensor Networks (WSN) have been a current trend in the research field and has many issues when there are multiple mobile sinks. Data dissemination gets critical as their locations have to be repeatedly updated and results in huge consumption of the restricted battery supply in sensor nodes. In this paper, we propose GCCP – NS, a grid based congestion control protocol with N –sinks that solves the data dissemination problem leading to congestion. We construct a dual level grid structure to trail the locations of all the source nodes that reports the information to the mobile sinks by monitoring the network in a hierarchical manner. As an added advantage, it aids in data dissemination based on query flooding from the mobile sinks using quorum based method within each cell in the grid and avoids congestion in an effective manner. Simulation results show that our proposed protocol outperforms the other schemes in terms of packet delivery ratio, energy expenditure and throughput

An Individual Node Delay Based Efficient Power Aware Routing Protocol for Wireless Heterogeneous Sensor Networks

Miscellaneous node transmission ranges builds up Wireless Heterogeneous Sensor Networks (WHSNs). Designing an efficient, reliable and scalable routing protocol for WHSNs with intermittent asymmetric links is a challenging task. In this paper, we propose an efficient power aware routing scheme for WHSNs, which can provide loop-free, stateless, source-to-sink routing scheme without using prior information about neighbor. It uses both symmetric and asymmetric links to forward data from source to sink. The source node broadcasts location information to all its neighbor nodes. Each neighbor node calculates a delay slot based on the information obtained from the source to forward its power value to it. The node that has a minimum delay slot forwards the power earlier than the other nodes during contention phase and the delay slot is used to suppress the selection of unsuitable low-power nodes at that time. We also prove that our protocol is loop-free assuming no failures in greedy forwarding. By simulations we show that our protocol significantly outperforms the existing protocols in WHSNs

Biohydrogen production using algae : Potentiality, economics and challenges

The biohydrogen production from algal biomass could ensure hydrogen's sustainability as a fuel option at the industrial level. However, some bottlenecks still need to be overcome to achieve the process's economic feasibility. This review article highlights the potential of algal biomasses for producing hydrogen with a detailed explanation of various mechanisms and enzymes involved in the production processes. Further, it discusses the impact of various experimental parameters on biohydrogen production. This article also analyses the significant challenges confronted during the overall biohydrogen production process and comprehends the recent strategies adopted to enhance hydrogen productivity. Furthermore, it gives a perception of the economic sustenance of the process. Moreover, this review elucidates the future scope of this technology and delineates the approaches to ensure the viability of hydrogen production

Engineering principles and process designs for phosphorus recovery as struvite: A comprehensive review

The rising population relies heavily on expensive phosphate (P) fertilizers for its agricultural productivity that qualms the national food security. Globally, there is a growing concern for the profound reliance on finite phosphorite reservoirs for commercial phosphate fertilizers’ qualitative and quantitative production. On the contrary, uncontrolled discharging of nutrient-rich wastewaters into natural streams, affecting the aquatic ecosystem. These critical situations have caused a scientific threat that has forced the researchers to explore other opportunities for the conservation of nutrient resources, recovery, and recycling. This review examines the nutrient recovery paradigms for struvite production by curtailing the nutrient gap between wastewater treatment and agricultural productivity. It comprehends the fundamental chemistry, thermodynamics, and factors influencing the struvite production process with its detailed mechanisms. Further, it deliberates the possible struvite engineering strategies, including process designs to enhance P recovery at the lab, pilot, and commercial scale. Also, it emphasizes the applications of nutrient-loaded struvite as a slow-release fertilizer and the challenges associated with economic feasibility and scaling up of the process in recent decades

Biochar seeding properties affect struvite crystallization for soil application

Struvite crystallization is a viable approach for recovering phosphorus from phosphorus-rich solutions such as urine and wastewater. However, designing seed materials to promote crystal growth and enhance the efficiency of struvite crystallization remains an area of active research. In this study, we investigated the seeding characteristics of biochars on struvite crystallization and the impact of biochar feedstock type and production temperature on the process. Microwave-pyrolyzed biochars produced from different feedstocks and under different temperatures were examined as seeding materials for struvite crystallization from urine and the influence of biochar properties on the overall struvite yield, nutrient recovery and struvite crystal size. Sawdust biochar (lignocellulosic biomass) produced at 500 ​°C had the highest struvite yield (7.91 ​g ​L−1), phosphate (97.9%) and ammonium recovery (87.1%), and relative crystal size (85.2%) compared to the non-seeded treatment due to its higher surface area, pore volume, and hydrophobicity of the biochar. Manure pellet biochar (non-lignocellulosic biomass) produced at 500 ​°C also exhibited performance comparable to sawdust biochar produced at 500 ​°C. Increasing pyrolysis temperature increased biochar's hydrophobicity, zeta potential, electrophoretic mobility and bulk density, irrespective of the feedstock type, thereby improving the seeding process. The ash content of biochar was negatively correlated with its surface area, pore volume, and particle size, but positively correlated with biochar's bulk density and suspension stability. In conclusion, feedstock type and pyrolysis temperature significantly affected biochar properties, which interactively influenced struvite crystallization. Therefore, biochars should be carefully selected to improve their efficiency for phosphorus recovery from phosphorus-containing solutions such as urine and wastewater, with the recovered phosphorus being used for soil applications

Integrated biomolecular and bioprocess engineering strategies for enhancing the lipid yield from microalgae

Algal biofuels have received wide attention in recent years for its potential to reduce the dependence on conventional fossil fuels. Despite the portrayed advantages of high growth rate, carbon sequestration and waste remediation; large scale application of microalgal biofuels is still lacking because of the lower percentage of extractable lipids obtained from the harvested biomass. Thus, there is a substantial impetus to analyse the strategies for enhancing the lipid profile and yield to improve the microalgal biofuel quality as well as to reduce the costs incurred at field scale. Several biochemical and molecular strategies to increase the algal lipid accumulation has gained huge scientific interest in recent years and have opened up new avenues for algal biorefinery. However, the time and cost involved as well as the ecological risks associated with real-time applications often restricts their utilization. The present review gathers a compendium of the key milestones associated with the recent approaches of biochemical, genetic and metabolic engineering for lipid quantity and quality enhancement. Biochemical and engineering aspects of coercing the cells to environmental stress and altering the mode of nutrition has been elucidated. The advancements in genetic and metabolic engineering, the associated risk factors and the future perspectives have been highlighted. Strategic integration of the bioprocess and biomolecular techniques to explore its synergistic impact to rationally engineer microalgae with improved triacylglycerols has been emphasized. Assessment of the long term risks associated herewith can be used to avert the challenges, making algal biofuels a commercial reality in future

Nanozymes in Point-of-Care Diagnosis: An Emerging Futuristic Approach for Biosensing

Abstract Nanomaterial-based artificial enzymes (or nanozymes) have attracted great attention in the past few years owing to their capability not only to mimic functionality but also to overcome the inherent drawbacks of the natural enzymes. Numerous advantages of nanozymes such as diverse enzyme-mimicking activities, low cost, high stability, robustness, unique surface chemistry, and ease of surface tunability and biocompatibility have allowed their integration in a wide range of biosensing applications. Several metal, metal oxide, metal–organic framework-based nanozymes have been exploited for the development of biosensing systems, which present the potential for point-of-care analysis. To highlight recent progress in the field, in this review, more than 260 research articles are discussed systematically with suitable recent examples, elucidating the role of nanozymes to reinforce, miniaturize, and improve the performance of point-of-care diagnostics addressing the ASSURED (affordable, sensitive, specific, user-friendly, rapid and robust, equipment-free and deliverable to the end user) criteria formulated by World Health Organization. The review reveals that many biosensing strategies such as electrochemical, colorimetric, fluorescent, and immunological sensors required to achieve the ASSURED standards can be implemented by using enzyme-mimicking activities of nanomaterials as signal producing components. However, basic system functionality is still lacking. Since the enzyme-mimicking properties of the nanomaterials are dictated by their size, shape, composition, surface charge, surface chemistry as well as external parameters such as pH or temperature, these factors play a crucial role in the design and function of nanozyme-based point-of-care diagnostics. Therefore, it requires a deliberate exertion to integrate various parameters for truly ASSURED solutions to be realized. This review also discusses possible limitations and research gaps to provide readers a brief scenario of the emerging role of nanozymes in state-of-the-art POC diagnosis system development for futuristic biosensing applications

Recent advances and future prospects of electrochemical processes for microalgae harvesting

Over the years, algae have found wide scope of utility in a variety of environmentally beneficial processes like biofuel production, removal of heavy metals from wastewater sources for potential bioremediation, monitoring water pollution and source of animal nutrition. However, the conventional harvesting methods pose a set-back in terms of energy, cost and operational complications due to the small size of microalgae. Of all the processes, harvesting alone corresponds to approximately 30% of the total production costs. Recent advancements in the microalgal technology have brought many efficient techniques into use for improved recovery of microalgae. This review comprehends the development, principle, influencing parameters and directions to future research of one of the state-of-the-art approaches for harvesting microalgae, electrochemical technology. Though this area was previously explored for its application in wastewater treatment, it has lately gained momentum in the field of microalgae due to its economic efficiency. This paper highlights the three prime processes used to yield microalgae namely electroflocculation, electroflotation and a combined electrocoagulation-flotation (ECF) system. Several encroachments and strategies among these techniques have also been elucidated. The review focusses on the effect of most significant process controlling parameters such as reactor and electrode design, various surface properties of microalgae, current, pH, salinity and agitation that influence harvesting. In addition, the economy and energy aspects that emphasize the welfares of this technology over others have been extensively discussed. The overall work aims to provide an insight into the electrochemical methods, their challenges and opportunities that might be beneficial for carrying out further research and scope for industrial applications

Five year results of a 3-month and two 5-month regimens for the treatment of sputum-positive pulmonary tuberculosis in South India

A controlled study of three short-course regimens was undertaken in South Indian patients with newly diagnosed, sputum-positive pulmonary tuberculosis. The patients were allocated at random to one of three regimens: a) Rifampicin, streptomycin, isoniazid and pyrazinamide daily for 3 months (R3); b) the same regimen as above but followed by streptomycin, isoniazid and pyrazinamide twice-weekly for a further period of 2 months (R5); c) the same as R5 but without rifampicin (25). A bacteriological relapse requiring treatment occurred by 5 years in 16.8% of 113 R3,5.2% of 97 R5, and 20.0% of 115 25 patients with organisms sensitive to streptomycin and isoniazid initially. The differences in the relapse rates between the R3 and R5 regimens and the R5 and 25 regimens were statistically significant (p < 0.01 for both). Considering patients with organisms initially resistant to streptomycin or isoniazid or both, 7 of 52 patients (4 R3,2 R5,l 25) had a bacteriological relapse requiring retreatment

Peroxidase-Mimicking Activity of Biogenic Gold Nanoparticles Produced from Prunus nepalensis Fruit Extract: Characterizations and Application for the Detection of Mycobacterium bovis

[Image: see text] In the present study, a facile, eco-friendly, and controlled synthesis of gold nanoparticles (Au NPs) using Prunus nepalensis fruit extract is reported. The biogenically synthesized Au NPs possess ultra-active intrinsic peroxidase-like activity for the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of H(2)O(2). Chemical analysis of the fruit extract demonstrated the presence of various bioactive molecules such as amino acids (l-alanine and aspartic acids), organic acids (benzoic acid and citric acid), sugars (arabinose and glucose), phenolic acid, and bioflavonoids (niacin and myo-inositol), which likely attributed to the formation of stable biogenic Au NPs with excellent peroxidase-mimicking activity. In comparison with the natural horseradish peroxidase (HRP) enzyme, the biogenic Au NPs displayed a 9.64 times higher activity with regard to the reaction velocity at 6% (v/v) H(2)O(2), presenting a higher affinity toward the TMB substrate. The Michaelis–Menten constant (K(M)) values for the biogenic Au NPs and HRP were found to be 6.9 × 10(–2) and 7.9 × 10(–2) mM, respectively, at the same concentration of 100 pM. To investigate its applicability for biosensing, a monoclonal antibody specific for Mycobacterium bovis (QUBMA-Bov) was directly conjugated to the surface of the biogenic Au NPs. The obtained results indicate that the biogenic Au NPs-QUBMA-Bov conjugates are capable of detecting M. bovis based on a colorimetric immunosensing method within a lower range of 10(0) to 10(2) cfu mL(–1) with limits of detection of ∼53 and ∼71 cfu mL(–1) in an artificial buffer solution and in a soft cheese spiked sample, respectively. This strategy demonstrates decent specificity in comparison with those of other bacterial and mycobacterial species. Considering these findings together, this study indicates the potential for the development of a cost-effective biosensing platform with high sensitivity and specificity for the detection of M. bovis using antibody-conjugated Au nanozymes