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Cellulose is the most abundant polysaccharide on earth. It has a large number of desirable properties. Its low toxicity makes it more useful for a variety of applications. Nowadays, its composites are used in most engineering fields. Composite consists of a polymer matrix and use as a reinforcing material. By reducing the cost of traditional fibers, it has an increasing demand for environment-friendly purposes. The use of these types of composites is inherent in moisture absorption with hindered natural fibers. This determines the reduction of polymer composite material. By appropriate chemical surface treatment of cellulose composite materials, the effect could be diminished. The most modern and advanced techniques and methods for the preparation of cellulose and polymer composites are discussed here. Cellulosic composites show a reinforcing effect on the polymer matrix as pointed out by mechanical characterization. Researchers tried their hard work to study different ways of converting various agricultural by-products into useful eco-friendly polymer composites for sustainable production. Cellulose plays building blocks, that are critical for polymer products and their engineering applications. The most common method used to prepare composites is in-situ polymerization. This help to increase the yields of cellulosic composites with a significant enhancement in thermal stability and mechanical properties. Recently, cellulose composites used as enhancing the incorporation of inorganic materials in multi-functional properties. Furthermore, we have summarized in this review the potential applications of cellulose composites in different fields like packaging, aerogels, hydrogels, and fibers.
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Celulose , Polímeros , Celulose/química , Estudos ProspectivosRESUMO
Textile and printing industries play a vital role in the economy of any country. But the effluents of these industries, which contain toxic Methylene Blue (MB) dye when mixed with fresh water, make it unfit for human health and aquatic life. For the removal of MB, different adsorbents were used, but they were expensive, non-biodegradable or less effective. In this research, novel carboxymethyl starch grafted poly 2-carboxyethyl acrylate (CM-St-g-P2CEtA) was synthesized by reacting carboxymethyl starch with 2-carboxyethyl acrylate. The reaction followed a free radical polymerization mechanism. The structure and properties of CM-St-g-P2CEtA were investigated by advanced analytical techniques. The CM-St-g-P2CEtA was employed for the remediation of Methylene Blue (MB) dye from wastewater. The removal percentage (%R) of MB was checked under different parameters, like different pH levels, different initial concentrations of dye, different adsorbent doses, and different contact times. The results obtained during the experiment were subjected to different adsorption and kinetic models. In the kinetic investigation, the experimental results were best represented by the pseudo-second-order kinetic model due to its high R2 value of 0.999. Similarly, with a regression coefficient (R2) value of 0.947, the Langmuir adsorption isotherm was best represented by the experimental results. The Langmuir adsorption model showed that MB dye was adsorbed on the surface of CM-St-g-P2CEtA in a monolayer pattern. The pseudo 2nd order kinetic model suggested that the adsorption process favored chemisorption mechanism. The CM-St-g-P2CEtA showed maximum percentage removal efficiency (%R) of 99.3% for MB dye.
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Águas Residuárias , Poluentes Químicos da Água , Humanos , Azul de Metileno/química , Poluentes Químicos da Água/química , Concentração de Íons de Hidrogênio , Adsorção , CinéticaRESUMO
Epoxy resins are important thermosetting polymers. They are widely used in many applications i.e., adhesives, plastics, coatings and sealers. Epoxy molding compounds have attained dominance among common materials due to their excellent mechanical properties. The sol-gel simple method was applied to distinguish the impact on the colloidal time. The properties were obtained with silica-based fillers to enable their mechanical and thermal improvement. The work which we have done here on epoxy-based nanocomposites was successfully modified. The purpose of this research was to look into the effects of cellulose nanocrystals (CNCs) on various properties and applications. CNCs have recently attracted a lot of interest in a variety of industries due to their high aspect ratio, and low density which makes them perfect candidates. Adding different amounts of silica-based nanocomposites to the epoxy system. Analyzed with different techniques such as Fourier-transformed infrared spectroscope (FTIR), thermogravimetric analysis (TGA) and scanning electronic microscopic (SEM) to investigate the morphological properties of modified composites. The various %-age of silica composite was prepared in the epoxy system. The 20% of silica was shown greater enhancement and improvement. They show a better result than D-400 epoxy. Increasing the silica, the transparency of the films decreased, because clustering appears. This shows that the broad use of CNCs in environmental engineering applications is possible, particularly for surface modification, which was evaluated for qualities such as absorption and chemical resistant behavior.
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Celulose , Nanopartículas , Celulose/química , Celulose/ultraestrutura , Porosidade , Água/química , Dióxido de Silício/química , Nanopartículas/químicaRESUMO
Xanthomonas translucens pv. cerealis causes bacterial leaf streak disease on small grain cereals. Type II and III secretion systems (T2SS and T3SS) play a pivotal role in the pathogenicity of the bacterium, while no data are available on the transcriptomic profile of wheat cultivars infected with either wild type (WT) or mutants of the pathogen. In this study, WT, TAL-effector mutants, and T2SS/T3SS mutants of X. translucens pv. cerealis strain NXtc01 were evaluated for their effect on the transcriptomic profile of two wheat cultivars, 'Chinese Spring' and 'Yangmai-158', using Illumina RNA-sequencing technology. RNA-Seq data showed that the number of differentially expressed genes (DEGs) was higher in Yangmai-158 than in Chinese Spring, suggesting higher susceptibility of Yangmai-158 to the pathogen. In T2SS, most suppressed DEGs were related to transferase, synthase, oxidase, WRKY, and bHLH transcription factors. The gspD mutants showed significantly decreased disease development in wheat, suggesting an active contribution of T2SS in virulence. Moreover, the gspD mutant restored full virulence and its multiplication in planta by addition of gspD in trans. In the T3SS-deficient strain, downregulated DEGs were associated with cytochrome, peroxidases, kinases, phosphatases, WRKY, and ethylene-responsive transcription factors. In contrast, upregulated DEGs were trypsin inhibitors, cell number regulators, and calcium transporter. Transcriptomic analyses coupled with quantitative real-time-PCR indicated that some genes are upregulated in Δtal1/Δtal2 compared with the tal-free strain, but no direct interaction was observed. These results provide novel insight into wheat transcriptomes in response to X. translucens infection and pave the way for understanding host-pathogen interactions.
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Triticum , Xanthomonas , Triticum/genética , Triticum/microbiologia , Transcriptoma , Doenças das Plantas/microbiologia , Xanthomonas/genética , Proteínas de Bactérias/genéticaRESUMO
The current study was designed to evaluate the antioxidant, anticancer and antimicrobial activities of silver nanoparticles (AgNPs) biosynthesized by Spirulina platensis extract. The biosynthesized silver nanoparticles were characterized using Fourier transform infrared (FT-IR) analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis. The antioxidant activity of the biosynthesized AgNPs were determined via DPPH radical scavenging assay while its anticancer activity was determined using the MTT assay. The antimicrobial activity of the biosynthesized AgNPs were analyzed by disc diffusion method. Spirulina platensis acts as a reducing and capping agent. The efficacy of silver nanoparticles (AgNPs) in inhibiting the growth of Gram-negative bacteria, specifically Acetobacter, Klebsiella, Proteus vulgaris, and Pseudomonas aeruginosa, was assessed by the utilisation of the diffusion method. The study aimed to evaluate the efficacy of biosynthesized silver nanoparticles (AgNPs) against many strains of Pseudomonas aeruginosa bacteria. The findings of the study revealed that when administered in doses of 50â µl, 75â µl, and 100â µl, the largest observed zone of inhibition corresponded to measurements of 10.5â mm, 14â mm, and 16â mm, respectively. A zone of inhibition with dimensions of 8â mm, 10.5â mm, and 12â mm was detected during testing against Acetobacter at concentrations of 50â µl, 75â µl, and 100â µl, respectively. The findings also indicate that there is a positive correlation between the concentration of AgNP and the DPPH scavenging ability of silver nanoparticles. The percentage of inhibition observed at concentrations of 500â µg/ml, 400â µg/ml, 300â µg/ml, 200â µg/ml, and 100â µg/ml were recorded as 80±1.98, 61±1.98, 52±1.5, 42±1.99, and 36±1.97, respectively. In addition, it was observed that the silver nanoparticles exhibited the greatest antioxidant activity at a concentration of 500â g/ml, with a measured value of 80.89±1.99. The IC-50 values, representing the inhibitory concentration required to achieve 50 % inhibition, were found to be 8.16, 19.15, 30.14, 41.13, and 63.11 at inhibition levels of 36±1.97, 42±1.99, 52±1.5, 61±1.98, and 80±1.98, respectively.
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This study is based on the removal of methylene blue (MB) from aqueous solution by cost effective and biodegradable adsorbent carboxymethyl starch grafted polyvinyl pyrolidone (Car-St-g-PVP). The Car-St-g-PVP was synthesized by grafting vinyl pyrolidone onto carboxymethyl starch by free radical polymerization reaction. The structure and different properties of Car-St-g-PVP were determined by 1H NMR, FT-IR, XRD, TGA and SEM. A series of batch experiments were conducted for the removal of MB, The adsorption affecting factors such as temperature, contact time, initial concentration of MB dye, dose of Car-St-g-PVP and pH were studied in detail. The other parameters like the thermodynamic study, kinetics and isothermal models were fitted to the experimental data. The results showed that pseudo 2nd order kinetics and Langmuir's adsorption isotherms were best fitted to experimental data with regression coefficient R2 viz. 0.99 and 0.97. The kinetic study showed that the adsorption mechanism favored chemisorption. The Gibbs free energy (ΔG°) for the adsorption process was found to be -7.31 kJ/mol, -8.23 kJ/mol, -9.00 kJ/mol and -10.10 kJ/mol at 25 °C, 35 °C, 45 °C and 55 °C respectively. The negative values of ΔG° suggested the spontaneous nature of the adsorption process. Similarly, the positive values of entropy (ΔS°) and enthalpy (ΔH°) 91.27 J/k.mol and 19.90 kJ/mol showed the increasing randomness and endothermic nature of the adsorption process. The value of separation factor (RL) was found to be less than one (RL < 1), which supported the feasibility of the adsorption process. The maximum MB removal percentage (% R) was found to be 98.6%. So, these findings show that Car-St-g-PVP can be meritoriously used for the treatment of MB from wastewater.
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Azul de Metileno , Poluentes Químicos da Água , Adsorção , Ácidos Carboxílicos , Concentração de Íons de Hidrogênio , Cinética , Azul de Metileno/química , Polivinil , Povidona , Espectroscopia de Infravermelho com Transformada de Fourier , Amido , Termodinâmica , Águas ResiduáriasRESUMO
In this research, a new biodegradable and eco-friendly adsorbent, starch-grafted polymethyl methacrylate (St-g-PMMA) was synthesized. The St-g-PMMA was synthesized by a free radical polymerization reaction in which methyl methacrylate (MMA) was grafted onto a starch polymer chain. The reaction was performed in water in the presence of a potassium persulfate (KPS) initiator. The structure and different properties of the St-g-PMMA was explored by FT-IR, 1H NMR, TGA, SEM and XRD. After characterization, the St-g-PMMA was used for the removal of MB dye. Different adsorption parameters, such as effect of adsorbent dose, effect of pH, effect of initial concentration of dye solution, effect of contact time and comparative adsorption study were investigated. The St-g-PMMA showed a maximum removal percentage (R%) of 97% towards MB. The other parameters, such as the isothermal and kinetic models, were fitted to the experimental data. The results showed that the Langmuir adsorption and pseudo second order kinetic models were best fitted to experimental data with a regression coefficient of R2 = 0.93 and 0.99, respectively.
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Azul de Metileno , Poluentes Químicos da Água , Adsorção , Radicais Livres , Gentamicinas , Concentração de Íons de Hidrogênio , Cinética , Metacrilatos , Metilmetacrilatos , Polimerização , Polimetil Metacrilato , Espectroscopia de Infravermelho com Transformada de Fourier , Amido/química , Água , Poluentes Químicos da Água/químicaRESUMO
Xa1-mediated resistance to rice bacterial blight, caused by Xanthomonas oryzae pv. oryzae (Xoo), is triggered by transcription activator-like effectors (TALEs) and suppressed by interfering TALEs (iTALEs). TALEs interact with the rice transcription factor OsTFIIAγ1 or OsTFIIAγ5 (Xa5) to activate expression of target resistance and/or susceptibility genes. However, it is not clear whether OsTFIIAγ is involved in TALE-triggered and iTALE-suppressed Xa1-mediated resistance. In this study, genome-edited mutations in OsTFIIAγ5 or OsTFIIAγ1 of Xa1-containing rice 'IRBB1' and Xa1-transgenic plants of xa5-containing rice 'IRBB5' did not impair the activation or suppression of Xa1-mediated resistance. Correspondingly, the expression pattern of Xa1 in mutated OsTFIIAγ5 and OsTFIIAγ1 rice lines and 'IRBB1' rice was similar. In contrast, the expression of OsSWEET11 was repressed in rice lines mutated in OsTFIIAγ5 and OsTFIIAγ1. Bimolecular fluorescence complementation (BiFC) and co-immunoprecipitation assays showed that both TALE PthXo1 and iTALE Tal3a interacted with OsTFIIAγ1 and OsTFIIAγ5 in plant nuclei. These results indicated that TALE-triggered and iTALE-suppressed Xa1-mediated resistance to bacterial blight is independent of OsTFIIAγ1 or OsTFIIAγ5 in rice, and suggest that an unknown factor is potentially involved in the interaction of Xa1, TALEs and iTALEs.
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Resistência à Doença , Oryza , Doenças das Plantas/microbiologia , Fatores de Transcrição , Xanthomonas , Resistência à Doença/genética , Oryza/genética , Doenças das Plantas/genética , Proteínas de Plantas , Plantas Geneticamente Modificadas , Fatores de Transcrição/genéticaRESUMO
BACKGROUND: Bacterial blight of cotton (BBC), which is caused by the bacterium Xanthomonas citri pv. malvacearum (Xcm), is a destructive disease in cotton. Transcription activator-like effectors (TALEs), encoded by tal-genes, play critical roles in the pathogenesis of xanthomonads. Characterized strains of cotton pathogenic Xcm harbor 8-12 different tal genes and only one of them is functionally decoded. Further identification of novel tal genes in Xcm strains with virulence contributions are prerequisite to decipher the Xcm-cotton interactions. RESULTS: In this study, we identified six tal genes in Xss-V2-18, a highly-virulent strain of Xcm from China, and assessed their role in BBC. RFLP-based Southern hybridization assays indicated that Xss-V2-18 harbors the six tal genes on a plasmid. The plasmid-encoded tal genes were isolated by cloning BamHI fragments and screening clones by colony hybridization. The tal genes were sequenced by inserting a Tn5 transposon in the DNA encoding the central repeat region (CRR) of each tal gene. Xcm TALome evolutionary relationship based on TALEs CRR revealed relatedness of Xss-V2-18 to MSCT1 and MS14003 from the United States. However, Tal2 of Xss-V2-18 differs at two repeat variable diresidues (RVDs) from Tal6 and Tal26 in MSCT1 and MS14003, respectively, inferred functional dissimilarity. The suicide vector pKMS1 was then used to construct tal deletion mutants in Xcm Xss-V2-18. The mutants were evaluated for pathogenicity in cotton based on symptomology and growth in planta. Four mutants showed attenuated virulence and all contained mutations in tal2. One tal2 mutant designated M2 was further investigated in complementation assays. When tal2 was introduced into Xcm M2 and expressed in trans, the mutant was complemented for both symptoms and growth in planta, thus indicating that tal2 functions as a virulence factor in Xcm Xss-V2-18. CONCLUSIONS: Overall, the results demonstrated that Tal2 is a major pathogenicity factor in Xcm strain Xss-V2-18 that contributes significantly in BBC. This study provides a foundation for future efforts aimed at identifying susceptibility genes in cotton that are targeted by Tal2.
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Gossypium/microbiologia , Análise de Sequência de DNA/métodos , Efetores Semelhantes a Ativadores de Transcrição/genética , Xanthomonas/patogenicidade , Proteínas de Bactérias/genética , China , Elementos de DNA Transponíveis , Gossypium/crescimento & desenvolvimento , Mutação INDEL , Filogenia , Doenças das Plantas/microbiologia , Plasmídeos/genética , Polimorfismo de Fragmento de Restrição , Fatores de Virulência/genética , Xanthomonas/genéticaRESUMO
Bacterial leaf streak caused by different pathovars of Xanthomonas translucens is the most important seedborne bacterial disease of small grain cereals. However, variations in the virulence-associated genomic areas of the pathogen remain uninvestigated. In this study, the diversity of transcription activator-like effectors (TALE) was investigated using the Southern blotting of BamHI-digested genomic DNAs in the Iranian strains of X. translucens. All 65 X. translucens strains were assigned into 13 genotypes, where 57 X. translucens pv. undulosa strains were placed in genotypes 1 to 8, and seven X. translucens pv. translucens strains were placed in genotypes 9 to 12. Interestingly, we did not find any TALE genes in the strain XtKm7 (genotype 13), which showed to be pathogenic only on barley. Virulence and aggressiveness of these strains in greenhouse conditions were in agreement with the TALE-based clustering of the strains in the pathovar level, though variations were observed in the aggressiveness of X. translucens pv. undulosa strains. In general, strains containing higher numbers of putative TALE genes were more virulent on wheat and barley than strains containing fewer. This is the first TALE-based genetic diversity analysis on X. translucens strains and provides novel insights into the virulence repertories and genomic characteristics of the pathogen. Further investigations using TALE mutagenesis and complementation analysis are warranted to precisely elucidate the role of each detected X. translucens TALE in bacterial virulence and aggressiveness either on wheat or barley.
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Xanthomonas , Irã (Geográfico) , Doenças das Plantas , Efetores Semelhantes a Ativadores de TranscriçãoRESUMO
Ice formation and accretion on surfaces is a serious economic issue in energy supply and transportation. Recent strategies for developing icephobic surfaces are intimately associated with superwettability. Commonly, the superwettability of icephobic materials depends on their surface roughness and chemical composition. This article critically categorizes the possible strategies to mitigate icing problems from daily life. The wettability and classical nucleation theories are used to characterize the icephobic surfaces. Thermodynamically, the advantages/disadvantages of superhydrophobic surfaces are discussed to explain icephobic behavior. The importance of elasticity, slippery liquid-infused porous surfaces (SLIPSs), amphiphilicity, antifreezing protein, organogels, and stimuli-responsive materials has been highlighted to induce icephobic performance. In addition, the design principles and mechanism to fabricate icephobic surfaces with superwettability are explored and summarized.
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Carbon nanotubes (CNTs) have gained significant attention in the field of fluid dynamics and fluid flows due to their unique properties and the potential to enhance various aspects of fluid transport features. This article explores the behavior of Darcy-Forchheimer flow of Propylene glycol [Formula: see text] submerged single wall carbon nanotubes (SWCNT) and multi-wall carbon nanotubes (MWCNT). The flow features are examined over stretched preamble surface of sheet. Energy relation is acquired in manifestation of thermal radiation and Joule heating. Aspects of Arrhenius kinetics and chemical reaction are assimilated in mass transport relation. Furthermore, effects of intermolecular fluid friction is accounted. Flow prevailing mathematical model is acquired by implementing boundary layer assumptions. Transformations procedure is adapted to alter the dimensional model into non-dimensional one and then tackled through Runge-Kutta-Fehlberg method (RKF-45) in Mathematica. Effective consequences of influential flow controlling parameters on fluid velocity, thermal transport and concentration are inspected by plotting. Numerical computations for interesting engineering quantities like skin friction coefficient, mass and heat transfer rates are tabulated and investigated. It is noticed that thermal field boosts versus curvature variable, Eckert and Hartmann numbers. Retardation in mass concentration is noticed via Schmidt number and activation energy variable. Velocity field shows decreasing trend through porosity parameter, Hartmann number and Darcy-Forchheimer variable. Furthermore, it is noticed that magnitude of skin friction coefficient is higher for SWCNT as compared to MWCNT.
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Entropy generation is a concept that is primarily associated with thermodynamics and engineering, and it plays a crucial role in understanding and optimizing various processes and systems. Applications of entropy generation can be seen in turbo machinery, reactors, chillers, desert coolers, vehicle engines, air conditioners, heat transfer devices and combustion. Due to industrial applications entropy generation has gained attention of researchers. Owing such applications, current communication aims to model and analyzed the irreversibility in Sutterby nanoliquid flow by stretched cylinder. Momentum equation is reported by considering porosity, Darcy Forchheimer and magnetic field. While in energy equation radiation and Joule heating effects are accounted. Activation energy impact is accounted in the modeling of concentration equation. Thermodynamics second law is utilized for physical description of irreversibility analysis. Through similarity transformations dimensional equations representing flow are transformed to dimensionless ones. Numerical solution for ordinary system is obtained via Runge-Kutta-Fehlberg scheme in Mathematica platform through NDsolve code. Influence of prominent variables on velocity, entropy, temperature, Bejan number and concentration are graphically analyzed. Coefficient of skin friction, gradient of temperature and Sherwood number are numerically analyzed. The obtained results show that velocity field decreases through higher porosity and Forchheimer variables. Velocity and temperature curves shows an opposite trend versus magnetic parameter. A decay in concentration distribution is noticed through larger Schmidt number. Entropy generation amplifies against magnetic parameter and Brinkman number.
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In this research article, novel starch phosphate grafted polyvinyl imidazole (StP-g-PIMDZs) was synthesized. Firstly, a phosphate group was attached to starch polymer via a phosphorylation reaction. Next, 1-vinyl imidazole (VIMDZ) was grafted on the backbone of starch phosphate (StP) through a free radical polymerization reaction. The synthesis of these modified starches was confirmed by 1H NMR, 31P NMR and FT-IR techniques. The grafting of vinyl imidazole onto StP diminished the crystallinity. Due to the insertion of the aromatic imidazole ring, the StP-g-PIMDZs demonstrated greater thermal stability. The StP and StP-g-PIMDZs were used as sorbents for the adsorption of methylene blue dye (MBD) from the model solution. The maximum removal percentage for starch, StP, StP-g-PIMDZ 1, StP-g-PIMDZ 2 and StP-g-PIMDZ 3 was found to be 60.6%, 66.7%, 74.2%, 85.3 and 95.4%, respectively. The Pseudo second order kinetic model and Langmuir adsorption isotherm were best suited to the experimental data with R2 = 0.999 and 0.99, respectively. Additionally, the thermodynamic parameters showed that the adsorption process was feasible, spontaneous, endothermic and favored chemi-sorption mechanism.
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Azul de Metileno , Poluentes Químicos da Água , Azul de Metileno/química , Espectroscopia de Infravermelho com Transformada de Fourier , Poluentes Químicos da Água/química , Concentração de Íons de Hidrogênio , Termodinâmica , Adsorção , Cinética , AmidoRESUMO
In this communication irreversibility minimization in bio convective Walter's-B nanofluid flow by stretching sheet is studied. Suspended nanoparticles in Walter's-B fluid are stabilized by utilizing microorganisms. Total irreversibility is obtained via thermodynamics second law. The influences of applied magnetic field, radiation, Joule heating and activation energy are accounted in momentum, temperature and concentration equations. Furthermore thermophoresis and Brownian movement impacts are also accounted in concentration and temperature expressions. The flow governing dimensional equations are altered into dimensionless ones adopting transformation procedure. Homotopy Analysis Method (HAM) code in Mathematica is implemented to get the convergent series solution. The influences of important flow variables on temperature, velocity, motile density, irreversibility, mass concentration, Bejan number and physical quantities are analyzed graphically. The obtained results revel that the velocity profile decreases for escalating magnetic parameter and Forchheimer number. Entropy generation is increased for higher Brinkman variable while Bejan number declines versus Brinkman variable. The important observations are given at the end.
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Green and efficient removal of polluted materials are essential for the sustainability of a clean and green environment. Nanomaterials, particularly cellulose nanocrystals (CNCs), are abundant in nature and can be extracted from various sources, including cotton, rice, wheat, and plants. CNCs are renewable biomass materials with a high concentration of polar functional groups. This study used succinic anhydride to modify the surface of native cellulose nanocrystals (NCNCs). Succinic anhydride has been frequently used in adhesives and sealant chemicals for a long time, and here, it is evaluated for dye removal performance. The morphology and modification of CNCs studied using FTIR, TGA & DTG, XRD, SEM, AFM, and TEM. The ability of modified cellulose nanocrystals (MCNCs) to adsorb cationic golden yellow dye and methylene blue dye was investigated. The MCNCs exhibited high adsorption affinity for the two different cationic dyes. The maximum adsorption efficiency of NCNCs and MCNCs towards the cationic dye was 0.009 and 0.156 wt%. The investigation for adhesive properties is based on the strength and toughness of MCNCs. MCNCs demonstrated improved tensile strength (2350 MPa) and modulus (13.9 MPa) using E-51 epoxy system and a curing agent compared to 3 wt% composites. This research lays the groundwork for environmentally friendly fabrication and consumption in the industrial sector.
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Corantes , Nanopartículas , Corantes/química , Anidridos Succínicos , Adsorção , Celulose/química , Nanopartículas/química , CátionsRESUMO
Phazolicin (PHZ) is a peptide antibiotic exhibiting narrow-spectrum activity against rhizobia closely related to its producer, Rhizobium sp. strain Pop5. Here, we show that the frequency of spontaneous PHZ-resistant mutants in Sinorhizobium meliloti is below the detection limit. We find that PHZ can enter S. meliloti cells through two distinct promiscuous peptide transporters, BacA and YejABEF, which belong to the SLiPT (SbmA-like peptide transporter) and ABC (ATP-binding cassette) transporter families, respectively. The dual-uptake mode explains the lack of observed resistance acquisition because the simultaneous inactivation of both transporters is necessary for resistance to PHZ. Since both BacA and YejABEF are essential for the development of functional symbiosis of S. meliloti with leguminous plants, the unlikely acquisition of PHZ resistance via the inactivation of these transporters is further disfavored. A whole-genome transposon sequencing screen did not reveal additional genes that can provide strong PHZ resistance when inactivated. However, it was found that the capsular polysaccharide KPS, the novel putative envelope polysaccharide PPP (PHZ-protecting polysaccharide), as well as the peptidoglycan layer jointly contribute to the sensitivity of S. meliloti to PHZ, most likely serving as barriers that reduce the amount of PHZ transported inside the cell. IMPORTANCE Many bacteria produce antimicrobial peptides to eliminate competitors and create an exclusive niche. These peptides act either by membrane disruption or by inhibiting essential intracellular processes. The Achilles' heel of the latter type of antimicrobials is their dependence on transporters to enter susceptible cells. Transporter inactivation results in resistance. Here, we show that a rhizobial ribosome-targeting peptide, phazolicin (PHZ), uses two different transporters, BacA and YejABEF, to enter the cells of a symbiotic bacterium, Sinorhizobium meliloti. This dual-entry mode dramatically reduces the probability of the appearance of PHZ-resistant mutants. Since these transporters are also crucial for S. meliloti symbiotic associations with host plants, their inactivation in natural settings is strongly disfavored, making PHZ an attractive lead for the development of biocontrol agents for agriculture.
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Anti-Infecciosos , Sinorhizobium meliloti , Antibacterianos/farmacologia , Antibacterianos/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Anti-Infecciosos/farmacologia , Peptídeos/metabolismo , Bactérias Gram-Negativas/metabolismo , Sinorhizobium meliloti/genética , Sinorhizobium meliloti/metabolismo , Simbiose/genéticaRESUMO
The earth's nitrogen cycle relies on the effective conversion of nitrogen (N2) to ammonia (NH3). As a result, the research and development of catalysts that are earth-abundant, inexpensive, and highly efficient but do not need precious metals is of the utmost significance. In this investigation, we present a controlled synthesis technique to the fabrication of an iron oxide (Fe2O3) nanosheet array by annealing at temperatures ranging from 350 to 550 °C. This array will be used for the electrochemical reduction of atmospheric N2 to NH3 in electrolytes. The Fe2O3 nanosheet array that was produced as a result displays outstanding electrochemical performance as well as remarkable stability. When compared to a hydrogen electrode working under normal temperature and pressure conditions, the Fe2O3 nanosheet array produces an impressive NH3 production rate of 18.04 g per hour per mg of catalytically active material in 0.1 M KOH electrolyte, exhibiting an enhanced Faradaic efficiency (FE) of 13.5% at -0.35 V. This is accomplished by exhibiting an enhanced Faradaic efficiency (FE) of 0.1 M KOH electrolyte. The results of experiments and electrochemical studies reveal that the existence of cation defects in the Fe2O3 nanosheets plays an essential part in the enhancement of the electrocatalytic activity that takes place during nitrogen reduction reactions (NRR). This study not only contributes to the expanding family of transition-metal-based catalysts with increased electrocatalytic activity for NRR, but it also represents a substantial breakthrough in the design of catalysts that are based on transition metals, so it's a win-win. In addition, the use of Fe2O3 nanosheets as electrocatalysts has a lot of potential in algal membrane bioreactors because it makes nitrogen fixation easier, it encourages algae growth, and it makes nitrogen cycling more resource-efficient.
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Amônia , Reatores Biológicos , Estudos Prospectivos , NitrogênioRESUMO
The presence of dyes in contaminated water poses substantial dangers to the health of both humans and aquatic life. A process called precipitation polymerization was used to create unique cross-linked hexa-chlorocyclotriphosphazene-co-phenolphthalein (Hex-CCP-co-PPT) microspheres for the purpose of this research. Advanced methods such as X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and differential thermogravimetry (DTG) were used to characterise these microspheres. In a simulated solution, the performance of Hex-CCP-co-PPTs as a sorbent for removing MB dye was investigated, and the results showed an unprecedentedly high removal rate of 88.4% for MB. Temperature of 25 °C, a Hex-CCP-co-PPTs dose of 40 mg, an MB concentration of 20 ppm, an MB solution volume of 20 mL, a contact time of 40 min, and a pH of 9 were found to be the optimal experimental conditions. According to the results of the kinetic and adsorption analyses, the PSO and Langmuir adsorption models are the best ones to use. These models favour the chemi-sorption nature and mono-layered adsorption of MB in comparison to Hex-CCP-co-PPTs. Importantly, the thermodynamic analysis demonstrated that the process of removing MB by utilizing Hex-CCP-co-PPTs was endothermic and occurred spontaneously. These findings highlight the potential application of Hex-CCP-co-PPT microspheres in Algal Membrane Bioreactors (AMBRs) for the efficient and sustainable removal of dye from wastewater. This would contribute to the protection of ecosystems as well as the public's health.