Influence of the incorporated metal on template removal from MCM-41 type mesoporous materials

Al-modified MCM-41, La-modified MCM-41, and Ce-modified MCM-41 mesoporous materials were prepared with different molar ratios (Si/M = 10; 25; 50; 100 and 200) at room temperature. The materials were characterized using XRD, BET–BJH, and TG–DTA. The XRD showed four peaks, due to the ordered hexagonal array of parallel silica tubes, which could be indexed as (100), (110), (200), and (210), assuming a hexagonal unit cell. The surface area decreased as the concentration of the metal incorporated in the material increased. The thermal stability of the materials was around 650 °C. The CeO₂ phase made the mass transfer process more difficult, hindering Hofmann degradation and favoring oxidation.     

Antimicrobial activities of indole alkaloids from Tabernaemontana catharinensis

Tabernaemontana catharinensis root bark ethanol extract, EB2 fraction and the MMV alkaloid (12-methoxy-4-methylvoachalotine) were evaluated for their antimicrobial activities. T. catharinensis ethanol extract was effective against both strains of the dermatophyte Trichophyton rubrum at concentrations of 2.5 mg/mL (wild strain) and 1.25 mg/mL (mutant strain), while the EB2 fraction and MMV alkaloid showed a strong antifungal activity against wild and mutant strains with MIC values of <0.02 and 0.16 mg/mL, respectively. The EB2 fraction showed a strong antibacterial activity against ATCC strains of S. aureus, S. epidermidis, E. coli and P. aeruginosa with MICs from <0.02 to 0.04 mg/mL, as well as against resistant clinical isolates species of Enterococcus sp, Klebsiella oxytoca, Citrobacter, K. pneumoniae, P. mirabilis, S. aureus, S. epidermidis, E. coli and P. aeruginosa with MIC values ranging from 0.04 to 0.08 mg/mL. The MMV alkaloid presented a MIC of 0.16 mg/mL against the strains of S. aureus and E. coli ATCC. For the resistant clinical isolates Enterococcus sp, Citrobacter, S. aureus, S. epidermidis, E. coli and P. aeruginosa the MIC of MMV ranged from 0.08 to 0.31 mg/mL. The chromatography analysis of the EB2 fraction revealed the presence of indole alkaloids, including MMV, possibly responsible for the observed antimicrobial activity.     

Antibacterial and cytotoxic activities of the sesquiterpene lactones cnicin and onopordopicrin

The antimicrobial and cytotoxic activities of chloroform extracts from the weeds Centaurea tweediei and C. diffusa, and the main sesquiterpene lactones isolated from these species, onopordopicrin and cnicin, respectively, were assayed. Results show that the chloroform extracts from both Centaurea species possess antibacterial activities against a panel of Gram-positive and Gram-negative bacteria. Remarkable antibacterial activity against methicillin-resistant Staphylococcus aureus was also measured. Both the extracts and the purified sesquiterpene lactones show high cytotoxicity against human-derived macrophages. Despite this cytotoxicity, C. diffusa chloroform extract and cnicin are attractive candidates for evaluation as antibiotics in topical preparations against skin-associated pathogens.     

Relationship Between Science and Mathematics Teaching Efficacy of Preservice Elementary Teachers

The purpose of this study was to investigate the change in teacher efficacy beliefs about mathematics and science teaching during participation in methods courses and student teaching, as well as the relationship between mathematics and science teaching efficacy. Data revealed that, as science and mathematics teacher education in a methods course progressed, science and mathematics teaching efficacy significantly increased. This effect appeared to decrease slightly by the end of student teaching. Analysis of data indicated a significant difference in both the personal mathematics and personal science teaching efficacy scores, as well as mathematics outcome expectancy. Additionally, preservice teachers' personal mathematics and science teaching efficacies were directly related, as were their mathematics and science teaching outcome expectancies.     

Synthesis of 4-methoxy-1H-phenalen-1-one: a subunit related to natural phenalenone-type compounds

4-Methoxy-1H-phenalen-1-one (4-methoxyperinaphthenone, 1), a subunit found in some Musa phytoalexins and related natural products from the Haemodoraceae, was synthesized starting from 2-methoxynaphthalene in five steps and an overall yield of 36%. A Heck–Fujiwara coupling between ethyl acrylate and 1-bromonaphthalene afforded the corresponding (E)-naphthylpropanoic acid which, after hydrogenolysis, was subjected to a one-pot Friedel–Crafts acylation–DDQ dehydrogenation procedure to furnish 1.     

Refined Prediction and Observation of Dislocation Structures in Low Σ Symmetric Grain Boundaries

The grain boundary dislocation structures of three Fe–4at.% Si bicrystals with an additional misorientation of the order of 2° were studied by transmission electron microscopy (TEM), one S5 [001] (310) and two S9 [110] (1 [`1]\overline 1 4). It was found that in the S5 case two Burgers vectors of the structure are not simple basic complete displacement shift lattice (DSC) vectors and are larger than any one of them. This enabled formation of the preferred grain boundary dislocation (GBD) structure with a hexagonal net composed of three screw dislocations and an independent set of parallel edge dislocations. In the S9 case the GBD structure comprises three apparently independent sets of parallel dislocations. The Burgers vectors of two sets could be established as basic DSC vectors in screw and edge orientation, respectively, with respect to the GB plane. For the third set formed by separated groups of four dislocations no corresponding basic DSC vector exists. This case needs further investigation. The previously published table of predicted GBD structures for symmetrical coincidence boundaries up to S11 was refined according to the new results.     

Adsorption of silanes bearing nitrogenated Lewis bases on SiO2/Si (100) model surfaces

The present paper describes the one-pot procedure for the formation of self-assembled thin films of two silanes on the model oxidized silicon wafer, SiO2/Si. SiO2/Si is a model system for other surfaces, such as glass, quartz, aerosol, and silica gel. MALDI-TOF MS with and without a matrix, XPS, and AFM have confirmed the formation of self-assembled thin films of both 3-imidazolylpropyltrimethoxysilane (3-IPTS) and 4-(N-propyltriethoxysilane-imino)pyridine (4-PTSIP) on the SiO2/Si surface after 30 min. Longer adsorption times lead to the deposition of nonreacted 3-IPTS precursors and the formation of agglomerates on the 3-IPTS monolayer. The formation of 4-PTSIP self-assembled layers on SiO2/Si is also demonstrated. The present results for the flat SiO2/Si surface can lead to a better understanding of the formation of a stationary phase for affinity chromatography as well as transition-metal-supported catalysts on silica and their relationship with surface roughness and ordering. The 3-IPTS and 4-PTSIP modified SiO2/Si wafers can also be envisaged as possible built-on-silicon thin-layer chromatography (TLC) extraction devices for metal determination or N-heterocycle analytes, such as histidine and histamine, with "on-spot" MALDI-TOF MS detection.     

Aggregation equations with gradient potential as Radon measure and initial data in Besov-Morrey spaces

In this work, we present conditions to obtain a global-in-time existence of solutions to a class of nonlinear viscous transport equations describing aggregation phenomena in biology with sufficiently small initial data in Besov-Morrey spaces and gradient potential as a Radon measure. We also study the self-similarity and asymptotic stability of solutions at large times.     

Biopolymer Synthesized by Strains of Xanthomonas sp Isolate from Brazil Using Biodiesel-Waste

The future supplies and usage of glycerol are expected to increase as biodiesel plants increase production, and the output will greatly outpace demand. Biodiesel production has already had a significant impact on the price of refined glycerol. A major concern of glycerol producers is the reduced price of glycerol resulting from the increased production of biodiesel. Some alternative uses for this glycerol that have been investigated are substrates for fermentation process or the production of biosurfactants, fatty acids, biopolymers, and others products. This work had as objective to evaluate two strains of Xanthomonas sp isolate from Brazil for xanthan gum in orbital agitator, analizing the apparent viscosity of aqueous solutions and selecting viscosity. The experiments of xanthan gum production were realized in orbital agitator with 120 rpm agitation, for cells production, and 180rpm, for biopolymer production, under a 28 °C temperature. The rheology of the fermentation broth was analyzed by apparent viscosity and the polymer was recovered with ethanol (1:3, v/v). After its recovery, the productivity evaluation was performed. The productivity were 0.157 and 0.363 gL⁻¹ for C1 and 0.186 and 0.363 gL⁻¹ for C9 to media glycerol or glycerol and sucrose, respectively. The viscosity analysis was performed for aqueous solutions 3%, at 25 °C, the best apparent viscosity was obtained using gum synthesized with glycerol and sucrose (50:50) at 25 °C, 143 mPa.s⁻¹ from Xanthomonas sp C1.