Production of Thermophilic Endo-β-1,4-xylanases by <Emphasis Type="Italic">Aspergillus fumigatus</Emphasis> FBSPE-05 Using Agro-industrial By-products

In the present paper, endo-β-1,4-xylanase production by Aspergillus fumigatus was evaluated in solid-state fermentation using low-cost substrates such as sugarcane bagasse (SCB), brewer’s spent grain (BSG), and wheat bran (WB). The partial characterization of the crude enzyme was also performed. In the experimental conditions, the highest levels of endo-β-1,4-xylanase production by A. fumigatus FBSPE-05 occurred within 8 days incubation when using SCB/liquid medium at 1:2 ratio (219.5 U g⁻¹) and 4 days incubation when using WB/liquid medium at 1:1 ratio (215.6 U g⁻¹). Crude enzyme from this last condition was used to enzyme characterization, showing best enzyme activity at 60 °C and pH 6.0, which suggests a thermophilic endoxylanase. The crude enzyme retained 73% of its activity after 1 h at 60 °C, and zymogram has shown three bands of endo-β-1,4-xylanase activity, with different molecular masses. A. fumigatus FBSPE-05 was able to grow and produce good levels of endo-β-1,4-xylanase using agro-industrial by-products, making this strain worthy for further investigation. To our knowledge, this is the first study reporting the use of SCB and/or BSG as sole substrates for endoxylanase production by solid-state fermentation using A. fumigatus.     

Aza‐Diels–Alder reaction between cyclopentadiene and protonated N‐phenylethyliminoacetates of 8‐phenylmenthol and 8‐phenylneomenthol: a density functional theory study

The cycloaddition between glyoxylate imines possessing two chiral auxiliaries, N‐(R)‐ or N‐(S)‐1‐phenylethyl and 8‐phenylmenthyl or 8‐phenylneomenthyl, and cyclopentadiene is described. Computational calculations using density functional theory with the Becke, three‐parameter, Lee–Yang–Parr functional and the 6‐31G(d) basis set were performed to better understand the highly diastereoselective mechanism and the exo‐selectivity observed experimentally for these ionic aza‐Diels–Alder reactions. Copyright © 2011 John Wiley & Sons, Ltd.     

Radiation from a D-dimensional collision of shock waves: a remarkably simple fit formula

Recently we estimated the energy radiated in the head-on collision of two equal D-dimensional Aichelburg-Sexl shock waves, for even D, by solving perturbatively, to first order, the Einstein equations in the future of the collision. Here, we report on the solution for the odd D case. After finding the wave forms, we extract the estimated radiated energy for D=5, 7, 9, and 11 and unveil a remarkably simple pattern, given the complexity of the framework: (for all D) the estimated fraction of radiated energy matches the analytic expression 1/2-1/D, within the numerical error (less than 0.1%). Both this fit and the apparent horizon bound converge to 1/2 as D→∞.     

Comparing perfect and 2nd Voronoi decompositions: the matroidal locus

We compare two rational polyhedral admissible decompositions of the cone of positive definite quadratic forms: the perfect cone decomposition and the 2nd Voronoi decomposition. We determine which cones belong to both the decompositions, thus providing a positive answer to a conjecture of Alexeev and Brunyate (Invent. Math. doi:10.1007/s00222-011-0347-2, 2011). As an application, we compare the two associated toroidal compactifications of the moduli space of principal polarized abelian varieties: the perfect cone compactification and the 2nd Voronoi compactification.     

Resonant X-ray diffraction of self-assembled epitaxial systems: From direct to complementary chemical information

In this work we depict schematically the use of resonant (anomalous) X-ray diffraction as a tool to directly probe strain and composition of self-assembled semiconductor islands. By employing a direct analysis at the Eu L₃ edge its composition gradient is quantified for EuTe:SnTe capped islands. Projection maps are proposed to visualize the results, providing an alternative capability to infer quantum dot properties. A more complex methodology is applied to the study of InP:GaAs islands, in which complementary anomalous measurements are performed. For this system the number of samples analyzed allows us to extract the activation energy for Ga adatoms diffusion from the substrate to the islands.     

Effect of Bauhinia monandra Kurz Leaf Preparations on Embryonic Stages and Adult Snails of Biomphalaria glabrata (Say, 1818), Schistosoma mansoni Cercariae and Toxicity in Artemia salina

Biomphalaria glabrata snails constitute the main vector of schistosomiasis in Brazil, and Bauhinia monandra Kurz, the leaves of which contain BmoLL lectin with biocidal action, is a plant widely found on continents in which the disease is endemic. This work describes the composition of B. monandra preparations and the effect on embryos and adult snails, their reproduction parameters and hemocytes. We also describe the results of a comet assay after B. glabrata exposure to sublethal concentrations of the preparations. Additionally, the effects of the preparations on S. mansoni cercariae and environmental monitoring with Artemia salina are described. In the chemical evaluation, cinnamic, flavonoid and saponin derivatives were detected in the two preparations assessed, namely the saline extract and the fraction. Both preparations were toxic to embryos in the blastula, gastrula, trochophore, veliger and hippo stages (LC₅₀ of 0.042 and 0.0478; 0.0417 and 0.0419; 0.0897 and 0.1582; 0.3734 and 0.0974; 0.397 and 0.0970 mg/mL, respectively) and to adult snails (LC₅₀ of 6.6 and 0.87 mg/mL, respectively), which were reproductively affected with decreased egg deposition. In blood cell analysis, characteristic cells for apoptosis, micronucleus and binucleation were detected, while for comet analysis, different degrees of nuclear damage were detected. The fraction was able to cause total mortality of the cercariae and did not present environmental toxicity. Therefore, B. monandra preparations are promising in combating schistosomiasis since they can control both the intermediate host and eliminate the infectious agent, besides being safe to the environment.     

Survey on chemical,physical, and thermal prediction behaviors for sequential chemical treatments used to obtain cellulose from Imperata Brasiliensis

Journal of Thermal Analysis and Calorimetry - The effects of chemical treatment sequences on the chemical, physical, and mainly the thermal properties of Imperata Brasiliensis grass in the process...     

A complete generalization of Göllnitz’s “big” theorem

In the spirit of Göllnitz’s “big” partition theorem of 1967, we present a new mod-6 partition identity. Alladi et al. provided a four-parameter refinement of Göllnitz’s big theorem in 1995 via a key identity of generating functions and the method of weighted words. By means of this technique, two similar mod-6 identities of this type were discovered—one by Alladi in 1999 and one by Alladi and Andrews in 2015. We finish the picture by presenting and proving the fourth and final possible mod-6 identity in this spirit. Furthermore, we provide a complete generalization of mod-n identities of this type. Finally, we apply a similar argument to generalize an identity of Alladi et al. from 2003.

     

Self-degassing SARA ATRP mediated by Na2S2O4 with no external additives

The supplemental activator and reducing agent (SARA) atom transfer radical polymerization (ATRP) mediated by Na₂S₂O₄ in the presence of air, without external deoxygenation or additional oxygen scavengers, is reported for several vinyl monomers: methyl acrylate (MA), n-butyl acrylate (n-BA), methyl methacrylate (MMA), 2-(dimethylamino)ethyl methacrylate (DMAEMA), poly(ethylene glycol) methyl ether acrylate (OEOA), and styrene (Sty). The polymerizations can be conducted in aqueous medium or using organic/water mixtures as solvent, with low concentration of copper, near room temperature. In the absence of any external deoxygenation, several well-defined homopolymers and block copolymers were obtained (Ð < 1.3). The evolution of the oxygen concentration during the polymerizations was monitored with an optical oxygen sensor. The consumption of oxygen prior polymerization in ethanol/water mixtures was attributed to the combined presence of Na₂S₂O₄ and alkyl halide initiator, which led to a lower initiation efficiency (I_eff). This could be overcome by decreasing the headspace volume of the reaction. The system reported exhibited the potential to be scalable, which is very relevant from an industrial standpoint. © 2019 Wiley Periodicals, Inc. J. Polym. Sci. 2020 , 58, 145–153     

The effect of alkyl chain of the imidazolium ring on the poly(o-methoxyaniline)/ionic liquid supercapacitor performance

Journal of Solid State Electrochemistry - New materials can be developed using a known compound with enhanced properties modifying and controlling its microstructure, morphology, and density of...