•4.75–10mm and 10–20mm size RCA were used to replace NCA of similar size range.•Abrasion resistance of concrete made with RCA was investigated.•RCA reduces abrasion resistance of paving concrete but ...not beyond acceptable limit.•RCA can be used in paving concrete mixes.
Coarse aggregate has notable influence on concrete properties. The sustainability in concrete is generally achieved through reduced mining of natural resources required for the manufacturing of its basic constituents, by recycling of suitable industrial by-products or post-consumer materials including construction and demolition waste (CDW). CDW is composed of several materials depending on its locality of the origin. Recycled concrete aggregate (RCA) is obtained by crushing the concretized components of CDW. RCA is inhomogeneous with respect to its dynamic properties unlike natural coarse aggregate (NCA). A pavement concrete has to possess a proper strength and adequate abrasion resistance to resist surface wearing due to a moving traffic. This study presents the influence of using RCA as a replacement of NCA in paving concrete. Two series of concrete mixes, at two different water-cement ratios, that is, 0.44 and 0.38, were used in this study. The study exhibited that RCA reduces the abrasion resistance significantly yet it could be effectively used in pavement concrete.
Creatinine biosensing is a rapidly developing field owing to the clinical relevance of creatinine as a vital biomarker for several diseases associated with renal, thyroidal, and muscular ...dysfunctions. Over the years, we have observed numerous creatinine biosensing strategies, including the most widely studied enzymatic creatinine biosensors. Though the enzymatic approach provides excellent selectivity and reliability, it has certain drawbacks, which include high fabrication cost and poor storage stability (that is inherent to every enzyme-based biosensors). This has led to the development of non-enzymatic creatinine biosensors, of which electrochemical sensors are the most promising for point-of-care applications. However, only a limited number of studies have been conducted and there is a lack of reviews addressing the recent advances in this research area. Herein, we present for the first time, a review with a prime focus on the various strategies implemented in non-enzymatic electrochemical creatinine biosensing. We aim to offer a comprehensive context on the achievements and limitations of currently available non-enzymatic electrochemical creatinine biosensors and address the underlying factors pertaining to the interplay of modification/fabrication techniques with the sensitivity, selectivity, interferences, and long-term storage stability of the biosensor. We hope that this work shall prove to be seminal in the conception and advancement of future non-enzymatic electrochemical creatinine biosensors.
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•The review encompasses non-enzymatic electrochemical creatinine detection depending upon the modified electrode.•The use of nanoparticles for creatinine detection and the underlying principle of creatinine as a ligand is elaborated.•The review also evaluates few unconventional detection approaches such as non-enzymatic potentiometric creatinine detection etc.
Microplastics (<5 mm) have become an environmental hazard to natural ecosystems and humanity due to their ubiquitous presence in the environment, and possess detrimental effects on aquatic organisms. ...Sampling, extraction, and detection of microplastics from sediments, surface water, and biota are quite complex and challenging. Rigorous research on the abundance and distribution of microplastics in terrestrial and aquatic ecosystems is primarily attributed to instinctive anthropogenic actions like land-based activities. Although, the fate and transport of microplastics in the environment are uncertain. Therefore, this paper reviews current research progress on the occurrence and distribution of microplastic pollution in the riverine ecosystem. Detailed potential sources, sampling techniques, and experimental design have been discussed, along with the classification and detection of microplastics in the riverine sediment and surface water. Microplastic ingestion through riverine species is also discussed systematically which emphasizes the extraction of microplastics from different body parts of the organism. Different types of polymeric microplastic have been observed in rivers, for instance, PS, PE, PP, PA, PET, PVC, PDPE, LPDE, nylon, acrylic, etc. using spectroscopy. Fragments, foams, pellets, films, fibers and microbeads are common shapes of microplastic which are abundant in the riverine ecosystem. The ingestion and ecological concern of microplastics, along with adsorption mechanisms of toxic contaminants, such as heavy metals, organic pollutants, nutrients, antibiotics, etc. onto microplastics surface and their exposure to aquatic organisms have also been discussed. Microplastic pollution in riverine ecosystems is under global change stress due to ecotoxicological and geochemical consequences. Further, detailed policies intervention for plastics and microplastics mitigation have been focused which delineate for application of science and policy together with scientific evidence. Lastly, scientific knowledge gaps and future research prospective on microplastic pollution have been given, along with suggestions and policy recommendations.
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•Major sources of microplastic pollution in rivers are urbanization and anthropogenic activities.•Riverine fishes are the most exposed freshwater species to microplastics.•Heavy metals, organic contaminants, nutrients, and antibiotics are adsorbed onto microplastics, increases ecotoxicity.•Microplastics interaction with aquatic organisms leads to ecological damage in the riverine ecosystem.•Policies for the plastic ban are required to optimize plastic production and less exposure to the natural environment.
A constant need to increase the network capacity for meeting the growing demands of the subscribers has led to the evolution of cellular communication networks from the first generation (1G) to the ...fifth generation (5G). There will be billions of connected devices in the near future. Such a large number of connections are expected to be heterogeneous in nature, demanding higher data rates, lesser delays, enhanced system capacity and superior throughput. The available spectrum resources are limited and need to be flexibly used by the mobile network operators (MNOs) to cope with the rising demands. An emerging facilitator of the upcoming high data rate demanding next generation networks (NGNs) is device-to-device (D2D) communication. An extensive survey on device-to-device (D2D) communication has been presented in this paper, including the plus points it offers; the key open issues associated with it like peer discovery, resource allocation etc, demanding special attention of the research community; some of its integrant technologies like millimeter wave D2D (mmWave), ultra dense networks (UDNs), cognitive D2D, handover procedure in D2D and its numerous use cases. Architecture is suggested aiming to fulfill all the subscriber demands in an optimal manner. The Appendix mentions some ongoing standardization activities and research projects of D2D communication.
Proposed architecture for resource allocation in device-to-device (D2D) communication. In order to meet the rising subscriber demands and provide them satisfactory services, D2D communication is being looked upon as an emerging technology of the next generation networks. For optimal sharing of resources between the D2D users and cellular users in the cellular networks, a sectored antenna is used at the base station, dividing the entire coverage area into three sectors of 120° each. This supports reduction in interference between the two types of users thereby, improving system performance.
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•Roadmap of D2D communication through the generations of wireless communication.•Outline of D2D communication; supporting architectures and use cases.•Integrant features (like Ultra Dense networks, millimeter wave communication, cooperative communication, network coding etc.) to enhance utility of D2D communication in the next generation networks.•Key open challenges and some important algorithms to overcome them.•Proposed architecture for optimal resource allocation and throughput maximization.
Hydrothermal liquefaction is a thermo-chemical conversion process which uses water as a reaction medium at elevated pressure and temperature. It converts biomass and waste feedstock to biofuel and ...recovers water and fertilizers present in the feedstock. Hydrothermal liquefaction overcomes many technical limitations of the existing technologies such as anaerobic digestion, incineration, gasification, and pyrolysis and it offers a solution to water-energy-climate nexus. Hydrothermal liquefaction has been widely investigated to understand the mechanism and kinetics of hydrothermal liquefaction at different batch scales of operation. Significant efforts have been made recently to develop the kinetic models for various type of feedstocks to predict product yields despite having complex reaction mechanism and pathways. This article critically reviews past work and discuss the different types of mathematical models used to predict products yields and composition for different biomass and waste feedstocks. It encompasses summary of important characteristics of representative biomass and waste feedstocks and quality of biocrude product, experimental studies conducted for various predictive and kinetic model development. A few limitations on existing models were identified to focus for further study. Finally, suggestions have been incorporated with focus on improving hydrothermal liquefaction kinetic model for optimal product yields and composition under varying operating conditions for various feedstocks.
Nowadays, 5G is in its initial phase of commercialization. The 5G network will revolutionize the existing wireless network with its enhanced capabilities and novel features. 5G New Radio (5G NR), ...referred to as the global standardization of 5G, is presently under the <inline-formula> <tex-math notation="LaTeX">3^{\mathrm {rd}} </tex-math></inline-formula> Generation Partnership Project (3GPP) and can be operable over the wide range of frequency bands from less than 6GHz to mmWave (100GHz). 3GPP mainly focuses on the three major use cases of 5G NR that are comprised of Ultra-Reliable and Low Latency Communication (uRLLC), Massive Machine Type Communication (mMTC), Enhanced Mobile Broadband (eMBB). For meeting the targets of 5G NR, multiple features like scalable numerology, flexible spectrum, forward compatibility, and ultra-lean design are added as compared to the LTE systems. This paper presents a brief overview of the added features and key performance indicators of 5G NR. The issues related to the adaptation of higher modulation schemes and inter-RAT handover synchronization are well addressed in this paper. With the consideration of these challenges, a next-generation wireless communication architecture is proposed. The architecture acts as the platform for migration towards beyond 5G/6G networks. Along with this, various technologies and applications of 6G networks are also overviewed in this paper. 6G network will incorporate Artificial intelligence (AI) based services, edge computing, quantum computing, optical wireless communication, hybrid access, and tactile services. For enabling these diverse services, a virtualized network slicing based architecture of 6G is proposed. Various ongoing projects on 6G and its technologies are also listed in this paper.
Geopolymerisation of mechanically activated fly ash was studied at ambient (27
°C) and elevated (60
°C) temperatures by isothermal conduction calorimeter. Under both the conditions, mechanical ...activation enhanced the rate and decreased time of reaction. It was interesting to observe that in the samples milled for 45
min (median size ∼5
μm), a broad peak corresponding to geopolymerisation initiated at 27
°C after 32
h. The rate maxima at 60
°C, a measure of fly ash reactivity, showed a non-linear dependence on particle size and increased rapidly when the median size was reduced to less than 5–7
μm. Improvement in strength properties is correlated with median particle size, and reactivity of fly ash. The characterisation of the geopolymer samples by SEM-EDS, XRD and FTIR revealed that mechanical activation leads to microstructure and structural variations which can be invoked to explain the variation in the properties.
•Agriculture plays an important role in a country's economy. In modern intensive agricultural practices, chemical fertilizers and pesticides are applied on large scale to increase crop production in ...order to meet the nutritional requirements of the ever-increasing world population. However, rapid urbanization with shrinking agricultural lands, dramatic change in climatic conditions and extensive use of agrochemicals in agricultural practices has been found to cause environmental disturbances and public health hazards affecting food security and sustainability in agriculture. Besides this, agriculture soils are continuously losing their quality and physical properties as well as their chemical (imbalance of nutrients) and biological health due to indiscriminate use of agrochemicals. Plant-associated microbes with their plant growth- promoting traits have enormous potential to solve these challenges and play a crucial role in enhancing plant biomass and crop yield under greenhouse and field conditions. The beneficial mechanisms of plant growth improvement include enhanced availability of nutrients (i.e., N, P, K, Zn and S), phytohormone modulation, biocontrol of phytopathogens and amelioration of biotic and abiotic stresses. This plant-microbe interplay is indispensable for sustainable agriculture and these microbes may perform essential role as an ecological engineer to reduce the use of chemical fertilizers. Various steps involved for production of solid-based or liquid biofertilizer formulation include inoculum preparation, addition of cell protectants such as glycerol, lactose, starch, a good carrier material, proper packaging and best delivery methods. In addition, recent developments of formulation include entrapment/microencapsulation, nano-immobilization of microbial bioinoculants and biofilm-based biofertilizers. Thus, inoculation with beneficial microbes has emerged as an innovative eco-friendly technology to feed global population with available resources. This review critically examines the current state-of-art on use of microbial strains as biofertilizers in different crop systems for sustainable agriculture and in maintaining soil fertility and enhancing crop productivity. It is believed that acquisition of advanced knowledge of plant-PGPR interactions, bioengineering of microbial communities to improve the performance of biofertilizers under field conditions, will help in devising strategies for sustainable, environment-friendly and climate smart agricultural technologies to deliver short and long terms solutions for improving crop productivity to feed the world in a more sustainable manner.
Modern intensive agricultural practices face numerous challenges that pose major threats to global food security. In order to address the nutritional requirements of the ever-increasing world population, chemical fertilizers and pesticides are applied on large scale to increase crop production. However, the injudicious use of agrochemicals has resulted in environmental pollution leading to public health hazards. Moreover, agriculture soils are continuously losing their quality and physical properties as well as their chemical (imbalance of nutrients) and biological health. Plant-associated microbes with their plant growth- promoting traits have enormous potential to solve these challenges and play a crucial role in enhancing plant biomass and crop yield. The beneficial mechanisms of plant growth improvement include enhanced nutrient availability, phytohormone modulation, biocontrol of phytopathogens and amelioration of biotic and abiotic stresses. Solid-based or liquid bioinoculant formulation comprises inoculum preparation, addition of cell protectants such as glycerol, lactose, starch, a good carrier material, proper packaging and best delivery methods. Recent developments of formulation include entrapment/microencapsulation, nano-immobilization of microbial bioinoculants and biofilm-based biofertilizers. This review critically examines the current state-of-art on use of microbial strains as biofertilizers and the important roles performed by these beneficial microbes in maintaining soil fertility and enhancing crop productivity.
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PAKs, p21-activated kinases, play central roles and act as converging junctions for discrete signals elicited on the cell surface and for a number of intracellular signaling cascades. PAKs ...phosphorylate a vast number of substrates and act by remodeling cytoskeleton, employing scaffolding, and relocating to distinct subcellular compartments. PAKs affect wide range of processes that are crucial to the cell from regulation of cell motility, survival, redox, metabolism, cell cycle, proliferation, transformation, stress, inflammation, to gene expression. Understandably, their dysregulation disrupts cellular homeostasis and severely impacts key cell functions, and many of those are implicated in a number of human diseases including cancers, neurological disorders, and cardiac disorders. Here we provide an overview of the members of the PAK family and their current status. We give special emphasis to PAK1 and PAK4, the prototypes of groups I and II, for their profound roles in cancer, the nervous system, and the heart. We also highlight other family members. We provide our perspective on the current advancements, their growing importance as strategic therapeutic targets, and our vision on the future of PAKs.
•PAKs act as modifiers of the cell surface and intracellular signaling cascades.•PAKs function both in the cytoplasm and nucleus and regulation of gene expression.•Relevance of PAKs ranges from cellular homeostasis to pathobiology of human disease.•PAKs are dysregulated in cancer, and neurological, cardiac and other disorders.•Modifying PAK activity has emerged as a therapeutic approach for many disorders.
The advancement of technologies over years has poised Internet of Things (IoT) to scoop out untapped information and communication technology opportunities. It is anticipated that IoT will handle the ...gigantic network of billions of devices to deliver plenty of smart services to the users. Undoubtedly, this will make our life more resourceful but at the cost of high energy consumption and carbon footprint. Consequently, there is a high demand for green communication to reduce energy consumption, which requires optimal resource availability and controlled power levels. In contrast to this, IoT devices are constrained in terms of resources-memory, power, and computation. Low power wide area (LPWA) technology is a response to the need for efficient utilization of power resource, as it evinces characteristics such as the capability to proffer low power connectivity to a huge number of devices spread over wide geographical areas at low cost. Various LPWA technologies, such as LoRa and SigFox, exist in the market, offering a proficient solution to the users. However, in order to abstain the need of new infrastructure (like base station) that is required for proprietary technologies, a new cellular-based licensed technology, narrowband IoT (NBIoT), is introduced by 3GPP in Rel-13. This technology presents a good candidature to handle LPWA market because of its characteristics like enhanced indoor coverage, low power consumption, latency insensitivity, and massive connection support towards NBIoT. This survey presents a profound view of IoT and NBIoT, subsuming their technical features, resource allocation, and energy-efficiency techniques and applications. The challenges that hinder the NBIoT path to success are also identified and discussed. In this paper, two novel energy-efficient techniques "zonal thermal pattern analysis" and energy-efficient adaptive health monitoring system have been proposed towards green IoT.
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