In this work, the synthesis of Ni1−x Mg x Fe2O4 (0 ≤ x ≤ 1.0) nanoparticles by a facile microwave-assisted combustion method is reported with detailed study of the structural and optical properties. By employing techniques of x-ray diffraction (XRD) with Rietveld refinement, transmission electron microscope (TEM, HRTEM, TEM-EDX), Fourier transform infrared spectroscopy (FTIR) and UV-Visible spectroscopy, the synthesized nanoparticles are characterized and introduced for further study of size-confined properties. Nanocrystals of a pure cubic spinel structured phase with average particle size of 20–40 nm were successfully synthesized in the whole range of x. In consistence with Vegard's law for a solid solution lattice, the lattice constant increases linearly with the substitution for Ni2+ with the relatively larger Mg2+ cations. The Rietveld analysis of the observed XRD patterns reveals an inversed spinel structure in NiFe2O4 nanoparticles with a decreased inversion factor by Mg-substitution. The results of UV-Visible absorbance indicate a wide energy gap of about 3.6 eV for NiFe2O4 nanoparticles thatmonotonically tuned towards a narrow band gap by Mg-doping.

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Abstract Fucoidanase and alginate lyase are promising biocatalysts for several biotechnological applications. The sequentially extracted fucoidan and alginate from the brown macroalgae Sargassum latifolium were used for the optimization of a cost-effective culture medium for fucoidanase and alginate lyase production by the marine fungus Dendryphiella arenaria. Plackett–Burman statistical design was conducted for initial determination of the importance of 11 independent variables on enzyme potentiation, and the significant variables were further optimized using Box–Behnken design. The optimum conditions for fucoidanase production were fucoidan (1.5% w/v), NaCl (1.5%), urea (0.3%), and incubation period (2 days), which gives ~ 4 U mL−1 of crude fucoidanase. While, alginate (1.5% w/v), NaCl (4%), NH4Cl (0.3%), and incubation period (6 days) were the optimum conditions that enhanced alginate lyase production to ~ 24 U mL−1 . Additionally, a new protocol for the enzymatic saccharification of fucoidan and alginate was optimized using Box–Behnken design with respect to substrate concentration, enzyme dosage, and temperature. The enzymatic saccharification of citric acid-extracted fucoidan gave a maximum yield of reducing sugar 365 mg g−1 fucoidan, while the alkali-extracted alginate gave 439.66 mg g−1 alginate. The results showed that the two enzymes could be exploited for the efficient production of reducing sugars from fucoidan and alginate, which are the key substrate for producing biofuels from brown macroalgal biomass

Abstract. Oyster mushrooms (Pleurotus spp.) can bioconvert lignocellulosic residues due to the secretion of extracellular enzymes. The production of hydrolytic and oxidative enzymes by five Pleurotus spp. (P. ostreatus, P. columbinus, P. pulmonarius, P. sajor-caju, and P. floridanus), developed in the solid and liquid state of fermentation using three agro-wastes (rice straw, sugarcane bagasse, and cotton waste), as substrate was evaluated in this work. The total nitrogen and potassium percentage were the highest in the case of rice straw, (0.96% and 0.60%). Also, the biological efficiency (BE), from these results, was the highest in the case of P. sajor-caju and P. columbinus recorded 64.4% on rice straw. It was observed that the submerged liquid fermentation (SmF) was suitable for the growth of all Pleurotus species. Also, the high value of enzymatic activity was determined through this study was, higher in the submerged liquid fermentation SmF, than those produced during solid-state culture (SSF). Among proteolytic enzymes, protease produced by the five Pleurotus spp. presenting the highest enzymatic activity (23.80 U/mL) on SmF and (22.56 U/mg) on SSF. Considering the oxidative enzymes, laccase produced, the highest value (1.99 U/mL) of laccase activity of filtrate was estimated from P. ostreatus cultivated on sugarcane bagasse of SmF. Low enzyme level (0.39 U/mg) was manganese peroxidase, obtained from P. floridanus cultivated on the cotton waste of SSF. The enzymatic levels of α-amylase, β-amylase, cellulose, cellobiohydrolase, laccase, and lignin peroxidase were from 2.9-0.50 U/mL.

Abstract In the present study, silver nanoparticles (AgNPs) were synthesized via biological reduction of silver nitrate using extract of the fungus Fusariumverticillioides(green chemistry principle). The synthesized nanoparticles were spherical and homogenous in size. AgNPs were coated with polyethylene glycol (PEG) 6000, sodium dodecyl sulfate (SDS), and β-cyclodextrin (β-CD). The averaged diameters of AgNPs were 19.2±3.6, 13±4, 14±4.4, and 15.7±4.8 nm, for PEG-, SDS-, and β-CD-coated and uncoated AgNPs, respectively. PEG-coated AgNPs showed greater stability as indicated by a decreased sedimentation rate of particles in their water dis¬persions. The antibacterial activities of different AgNPs dispersions were investigated against Gram-positive bacteria (methicillin-sensitive and methicillin-resistant Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli) by determination of the minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs). MIC and MBC values were in the range of 0.93–7.5 and 3.75–15 μg/mL, respectively, which were superior to the reported values in literature. AgNPs-loaded hydrogels were prepared from the coated-AgNPs dispersions using several gelling agents (sodium carboxymethyl cellulose [Na CMC], sodium alginate, hydroxypropylmethyl cellulose, Pluronic F-127, and chitosan). The prepared formula¬tions were evaluated for their viscosity, spreadability, in vitro drug release, and antibacterial activity, and the combined effect of the type of surface coating and the polymers utilized to form the gel was studied. The in vivo wound-healing activity and antibacterial efficacy of Na CMC hydrogel loaded with PEG-coated AgNPs in comparison to the commercially available silver sulfadiazine cream (Dermazin®) were evaluated. Superior antibacterial activity and wound-healing capability, with normal skin appearance and hair growth, were demonstrated for the hydrogel formulations, as compared to the silver sulfadiazine cream. Histological examination of the treated skin was performed using light microscopy, whereas the location of AgNPs in the skin epidermal layers was visualized using transmission electron microscopy.

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The HTTP flooding attack is the hardest type of DDoS attacks to detect since the malicious packets are hidden in the huge amount of normal traffic. Most detection schemes available up to now use similarity method of communication attributes (i.e. fixed threshold for every attribute ) or machine learning algorithms.it is notable,however,that attributes number very dramatically according to the users activity. Also, using machine learning need a large amount of data for training.In this paper, we introduce a new detection scheme for HTTP flooding attack that exhausting servers. the proposed detection scheme is based on HTTP request/raspons protocol.During normal cases, any server can measure various statistical attributes for its users and their traffic. a server can keep the statistical attributes as a reference profile. during the attack time, measuring some attributes for every connection (i.e. Request number, Response number, Not finished connections number, Number of TCP packets, Number of UDP packets and Number of ICMP packets) then computes distance between its attributes and statistical attributes in normal cases. the proposed detection scheme uses small amount of data to specify the score for a normal connection, also it does not take into consideration a fixed threshold for every attribute in normal connections. Extensive trace-driven simulation has been conducted to demonstrate the efficiency of the proposed scheme in terms of its detection rate, probability of false positive and also average detection time.