The increasing volume of waste generated by various activities has increased interest in using waste to create sustainable construction materials to achieve possible benefits. In addition, using ...recycled materials to produce fresh concrete is a desirable option because of its low cost, lower landfill space requirement, and the completed concrete quality. Therefore, an experimental inquiry is undertaken to ascertain the impacts of up to 20 wt% cement displaced by Volcanic Pumice Powder (VPP) with the incorporation of 1% and 2% Recycled Nylon Fiber (RNF) on the mechanical properties of concrete composites following room temperature to high-temperature (600 °C) exposure. Fresh concrete characteristics tests were performed, including slump, compacting factor, Kelly ball penetration, and density. The heat resistance of the concrete was then measured by calculating the percentage decrease in weight, the splitting tensile strength, and the compressive strength of the specimens. Heating mainly raised VPP's pozzolanic reactivity and lowered high vapor pressure through melting RNF. Therefore, VPP and RNF-treated concrete had superior mechanical performance than control concrete even when exposed to elevated temperatures. Further, the microstructural modifications brought on by RNF and VPP additions were also explored by deploying Scanning Electron Microscopy (SEM). The use of VPP in concrete led to an improvement in fresh properties, while RNF demonstrated deterioration in the same qualities. Despite this, supervised machine learning techniques are a central focus of this investigation because of their potential to predict concrete characteristics accurately. To predict the fresh and mechanical characteristics of concrete, both the Random Forest (RF) and the K-Nearest Neighbors (KNN) algorithm, along with their ensemble model counterparts, were explored. The outcomes revealed that RNF and VPP considerably improved the concrete's heat resilience and mechanical characteristics and halted the concrete composites' explosive spalling behavior at 600 °C temperatures. To prevent strength loss at high temperatures, it was discovered that adding 1% RNF content to concrete with 10% VPP was the best combination. In addition, the high coefficient correlation (R2) value of the RF and the ensemble model indicates great accuracy in outcome prediction, while the low R2 value of the KNN model indicates that the KNN model is less accurate.
Display omitted
•Mechanical performance of concrete improved with VPP and RNF at high temperature.•Machine learning approach was found effective for fresh and mechanical properties.•Enhancement with VPP and RNF was visible in SEM pictures.
Massive multiple-input multiple-output (mMIMO) techniques can be combined with the non-orthogonal multiple access (NOMA) scheme in terahertz (THz) communication to achieve multiplexing gains and ...satisfy the ultra-high capacity and massive connectivity requirements. However, the development of a near-optimal solution for energy and spectral efficiency problems in a dynamic wireless cellular environment remains challenging. In this paper, a cooperative THz mMIMO-NOMA enabled base station is established to optimize the power consumption and maximize the spectral efficiency. A multi-layer mMIMO antenna architecture is used to perform dynamic sub-connected hybrid precoding in each layer. The fuzzy c-means clustering algorithm is used to group densely located users into clusters to efficiently use the power coefficients. To optimize the power distribution constraints and coordination of the hybrid precoding structure, a multi-agent deep reinforcement learning algorithm is developed, which operates in a distributive manner. Each base station layer involves an agent that trains a deep Q-network, and optimal actions are executed by sharing exchangeable network parameters among layers. The simulation results indicate that the proposed scheme is able to learn the trade-off between maximization of the energy efficiency and overall system capacity.
•UHPFRC has gained a great deal of increasing interest in structural engineering.•Size effects of UHPFRC were quantified with size-dependent stress–strain model.•A segmental moment-rotation is ...applied to quantify the UHPFRC member responses.•Enhance in ductility was achieved after concrete crushing with adding fibers.•Results not only increase due to material concrete strength but for brittle ductility.
Ultra-high-performance fiber-reinforced concrete (UHPFRC) has gained a great deal of increasing interest in structural engineering applications, particularly where high ductility, strength, and high impact resistance are of prime concern. This study focuses primarily on the size effects ductility characteristics of UHPFRC with varying fiber concentrations subjected to uniaxial compressive load. It shows how to process the data from compression cylinder tests to extract the size-dependent strain at peak stress to provide a generic size-dependent stress–strain analytical model. For a slenderness factor of 2, the predicted peak stress from the analytical model deviated 0.34%, 0.26%, and 10.5% from the experimental peak stress results for a fiber concentration of 1%, 2%, and 3%, respectively, indicating good estimate of the analytical model with the experimental results. Furthermore, a numerical flexural segmental moment-rotation approach is applied to incorporate an analytical model to quantify apparently disparate UHPFRC member strength and ductility. Tests have shown that it is not the enhancement in the material concrete compressive strength but the phenomenal brittle ductility nature, observed as a result of increasing the slenderness of the specimen; in contrast, a substantial increase in ductility was achieved after crushing of concrete due to the addition of fibers. A size-dependent analytical approach has estimated good fit with the experimental and other published results. Finally, numerical simulation using a segmental approach at the ultimate limit state of rotation dealing with flexural ductility is significantly influenced by the increase in slenderness factor of the specimens and fiber concentrations.
This is evident as the rotation capacity decreased by 62% and 75% for a slenderness factor of 3 and 4, respectively, compared to the slenderness factor 2, when the fiber concentration was 1%. Furthermore, for 2% fiber concentration, the decrease was 54%, and 80%, and for 3% fiber concentration, the decrease was found to be 49%, and 79% for the slenderness factor of 3 and 4, respectively in comparison to the slenderness factor 2, suggesting both slenderness factor and fiber concentration have a significant impact on the flexural ductility.
Ageratum conyzoides L. (Family—Asteraceae) is an annual aromatic invasive herb, mainly distributed over the tropical and subtropical regions of the world. It owns a reputed history of indigenous ...remedial uses, including as a wound dressing, an antimicrobial, and mouthwash as well as in treatment of dysentery, diarrhea, skin diseases, etc. In this review, the core idea is to present the antifungal potential of the selected medicinal plant and its secondary metabolites against different fungal pathogens. Additionally, toxicological studies (safety profile) conducted on the amazing plant A. conyzoides L. are discussed for the possible clinical development of this medicinal herb. Articles available from 2000 to 2020 were reviewed in detail to exhibit recent appraisals of the antifungal properties of A. conyzoides. Efforts were aimed at delivering evidences for the medicinal application of A. conyzoides by using globally recognized scientific search engines and databases so that an efficient approach for filling the lacunae in the research and development of antifungal drugs can be adopted. After analyzing the literature, it can be reported that the selected medicinal plant effectively suppressed the growth of numerous fungal species, such as Aspergillus, Alternaria, Candida, Fusarium, Phytophthora, and Pythium, owing to the presence of various secondary metabolites, particularly chromenes, terpenoids, flavonoids and coumarins. The possible mechanism of action of different secondary metabolites of the plant against fungal pathogens is also discussed briefly. However, it was found that only a few studies have been performed to demonstrate the plant’s dosage and safety profile in humans. Considered all together, A. conyzoides extract and its constituents may act as a promising biosource for the development of effective antifungal formulations for clinical use. However, in order to establish safety and efficacy, additional scientific research is required to explore chronic toxicological effects of ageratum, to determine the probability of interactions when used with different herbs, and to identify safe dosage. The particulars presented here not only bridge this gap but also furnish future research strategies for the investigators in microbiology, ethno-pharmacology, and drug discovery.
We use molecular dynamics simulations to investigate the material properties of cubic zinc blende Si
0.5
Ge
0.5
alloy nanowire (NW). We elucidate the effect of nanowire size, crystal orientations, ...and temperature on the material properties. We found that the reduction in the NW cross-sectional area results in lower ultimate tensile strength (UTS) and Young’s modulus. The 111 and 110 oriented NWs exhibit the highest fracture strength and fracture toughness, respectively. The increased temperature degrades the strength of the material and facilitates failure. The vacancy defects introduced via removal of either Si or Ge atoms exhibit similar behavior, and linear reduction of UTS and Young’s modulus are realized with an increased vacancy concentration. We observed intrinsic failure characteristics of the NW as insensitive to the temperature. Overall, the new understanding of material properties and failure characteristics of Si
0.5
Ge
0.5
NW elicited in this study will be a guide for designing Si–Ge-based nanodevices.
Graphical abstract
Display omitted
•The effect of various defects and temperature on thermal conductivity of silicene is studied using NEMD.•Only 5% of carbon doping are found to reduce the thermal conductivity of pure ...silicene by ~ 71%.•Reduction of thermal conductivity is more pronounced with the increased vacancy than carbon.•PDOS reveals the high-frequency regime exhibit a redshift for carbon-doped silicene.•Both pristine and carbon-doped silicene exhibit isotropic thermal conductivity behavior.
Silicene has recently grabbed tremendous attention in the scientific community owing to its superb electronic and thermal properties and the promise of high-efficiency thermoelectric operations. Notwithstanding rigorous analyses of its electronic properties, little attention has been paid so far to explore and tailor the thermal transport characteristics of silicene. This study employed optimized Tersoff potential to extensively investigate the thermal conductivity (TC) of pristine and defective silicene using non-equilibrium molecular dynamics (NEMD) simulations. We analyzed theinfluence of temperature variation, percentage of carbon doping, andmonovacancy concentration on the phonon TC along both armchair and zigzag directions and elucidated the underlying mechanisms that modulate these effects. The simulation results reveal excellent isotropic behavior of the material in the considered temperature regime. Our predicted room-temperature TC of pristine silicene of ~ 20 W/m.K shows excellent conformity with prior studies. Simulation results suggestthat the TC deteriorates significantly with increasing concentration of carbon doping. It is revealed that incorporating only 5% of carbon dopants can reduce the TC of silicene by ~ 71%. Meanwhile, with the increase in temperature from 100 K to 600 K, the thermal conductivities of both pristine and carbon-doped silicene are also found to decline dramatically by ~14 W/m.K and ~9 W/m.K, respectively. The vacancy defect study reveals that thermal conductivities of both pure and carbon-doped silicene are also a strong function of vacancy concentration and can be reduced by ~ 58% by removing only 1% of silicon atom from the pristine nanosheet. It is further disclosed that the impact of vacancy on regulating the TC is more pronounced in pristine silicene than the carbon-doped silicene. To obtain a detailed insight into the thermal transport mechanism, phonon density of states (PDOS) is computed using the fast Fourier transform of the atomic velocity autocorrelation function. The PDOS discloses interesting phonon spectrum features under impurity doping, temperature variation, and increased vacancy concentration. Overall, this study offers a comprehensive roadmap for engineering the thermal conductivity of silicene and will grease the wheels for designing efficient thermal management systems for the present silicon-based semiconductor industry.
COVID-19, which is caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has quickly spread over the world, posing a global health concern. The ongoing epidemic has ...necessitated the development of novel drugs and potential therapies for patients infected with SARS-CoV-2. Advances in vaccination and medication development, no preventative vaccinations, or viable therapeutics against SARS-CoV-2 infection have been developed to date. As a result, additional research is needed in order to find a long-term solution to this devastating condition. Clinical studies are being conducted to determine the efficacy of bioactive compounds retrieved or synthesized from marine species starting material. The present study focuses on the anti-SARS-CoV-2 potential of marine-derived phytochemicals, which has been investigated utilizing in in silico, in vitro, and in vivo models to determine their effectiveness. Marine-derived biologically active substances, such as flavonoids, tannins, alkaloids, terpenoids, peptides, lectins, polysaccharides, and lipids, can affect SARS-CoV-2 during the viral particle's penetration and entry into the cell, replication of the viral nucleic acid, and virion release from the cell; they can also act on the host's cellular targets. COVID-19 has been proven to be resistant to several contaminants produced from marine resources. This paper gives an overview and summary of the various marine resources as marine drugs and their potential for treating SARS-CoV-2. We discussed at numerous natural compounds as marine drugs generated from natural sources for treating COVID-19 and controlling the current pandemic scenario.
Cancer is one of the life-taking diseases worldwide and among cancer-related death; colorectal cancer is the third most. Though conventional methods of treatment are available, multidrug resistance ...and side effects are predominant. Physicians and scientists are working side by side to develop an effective medicament, which is safe and cost-effective. However, most failures are obtained when focused on the clinical perspective. This review mainly brings out the correlation between the curcumin and its use for the mitigation of colorectal cancer, the use of curcumin as a chemotherapeutic agent, chemosensitizer, and in a combination and synergistic approach. The pharmacokinetics and pharmacodynamics properties of curcumin and its formulation approach helps in giving an idea to develop new approaches for the treatment of colorectal cancer using curcumin.
Display omitted
Mitochondria are essential cellular organelles that act as metabolic centers and signaling platforms and have been identified as an important subcellular target in a broad range of neuropathologies. ...Studies on the role of mitochondria in neurological disorders have primarily focused on neurons. However, dysfunctional mitochondria in glial cells, particularly astrocytes, have recently gained research attention due to their close involvement in neuroinflammation and metabolic and neurodegenerative disorders. Furthermore, alterations in mitochondrial energy metabolism in astrocytes have been reported to modulate cellular morphology and activity and induce the release of diverse proinflammatory mediators. Moreover, emerging evidence suggests that dysregulation of mitochondrial dynamics characterized by aberrant fission and fusion events in glial cells is closely associated with the inflammatory activation of glia. In this mini-review, we cover the recent advances in the molecular aspects of astrocytic mitochondrial dynamics and their metabolic changes under the pathological conditions of the central nervous system (CNS).
Cancer treatment is improving widely over time, but finding a proper defender to beat them seems like a distant dream. The quest for identification and discovery of drugs with an effective action is ...still a vital work. The role of a membrane protein called P-glycoprotein, which functions as garbage chute that efflux the waste, xenobiotics, and toxins out of the cancer cells acts as a major reason behind the therapeutic failure of most chemotherapeutic drugs. In this review, we mainly focused on a multiple strategies by employing 5-Fluorouracil, curcumin, and lipids in Nano formulation for the possible treatment of colorectal cancer and its metastasis. Eventually, multidrug resistance and angiogenesis can be altered and it would be helpful in colorectal cancer targeting.We have depicted the possible way for the depletion of colorectal cancer cells without disturbing the normal cells. The concept of focusing on multiple pathways for marking the colorectal cancer cells could help in activating one among the pathways if the other one fails. The activity of the 5-Fluorouracil can be enhanced with the help of curcumin which acts as a chemosensitizer, chemotherapeutic agent, and even for altering the resistance. As we eat to survive, so do the cancer cells. The cancer cells utilize the energy source to stay alive and survive. Fatty acids can be used as the energy source and this concept can be employed for targeting the colorectal cancer cells and also for altering the resistant part.
Display omitted
•Colorectal cancer treatment failure is multidrug resistance and reoccurrence.•Resistance exhibits with the action of P-glycoprotein, which results in metastasis.•Lipids, 5-Fluorouracil and curcumin combination relapse colorectal cancer.•This dual drug approach provides a synergistic activity.•Focusing on metastasis with lymph node targeting with lipids.
PDF
