Experimental Design in the Optimization of a Microwave Acid Digestion Procedure of Biomorphic Ceramic Based on ZrO2

Abstract

The present work deals with the manufacturing of biomorphous ZrO₂-ceramics from oak wood as biological template structure. Oak wood was vacuum infiltrated with zirconia-sol. Subsequent pyrolysis in inert atmosphere at 800°C and annealing in air up to 1550°C resulted in the formation of porous, microcellular ZrO₂-ceramics. After the material characterization, we optimized the sample dissolution by acid attack in an oven under microwave irradiation. Experimental designs were used as a multivariate strategy for the effects evaluation of varying several variables. The optimization was performed using full factorial design 2⁴. Four variables (time, power, volume of HNO₃, and volume of HF) were considered as factors and as response the concentration of different metal ions in the optimization process.     

Tuning morphology of mesoporous titanium oxides through fluorinated surfactants-based systems

Four different fluorinated surfactant-based systems were used as template for the synthesis of highly ordered TiO₂ mesoporous materials with large-pore wormhole structures. The calcined materials exhibit large pore diameters (up to 5.9 nm), high surface areas (900–1,180 m² g^?1), pore volumes (0.90–1.25 cm³ g^?1) and thick pore walls (4.6–7.7 nm) depending of the synthesis route. It is established that the self-aggregation behavior of fluorinated amphiphile systems can be manipulate and provides a rich phase behavior to obtain well-organized titania sieves with adjustable pore size and surface topography. By comparison to titania and silica sieves obtained by the same procedure, it can be established that there is a deep interaction between head groups of fluorinated surfactants and Ti(IV)(iPrO)₄ showing that the inorganic precursor has a great influence on the properties of the final materials.     

EXTRACTION OP MANGANESE(II) BT MIXTURES OP DIDODECYLNAPHTHALENESOLFONIC ACID AND r-BUTYL- CYCLOHEXANO-15-CROWN-5: SPECTRAL EVIDENCE FOR THE FORMATION OF A MANGANESE(II) - CROWN ETHER COMPLEX

Addition of t-butylcyclohexano-15-crown-5 (tBC-15C5) induces a synergistic effect in the extraction of Mn²⁺ ion with didodecylnaphthalenesulfonic acid (HDDNS). This synergism is the result of the inner-sphere complexation of the crown ether to the manganese(II) ion. The formation of this complex, first suggested by distribution studies, has been confirmed by FTIR experiments. The C-O-C stretching bands for the crown ether ligand shift to lower frequency when Mn²⁺ ion is extracted into a CC14 solution of HDDNS and tBC15C5. A similar C-O-C Btretching band is observed for the crystalline complex [Mn(15C5 ) (Bu₃CS0₃)₂] (where 15C5 = 15-crown-5 and Bu = n-butyl).Formation of analogous complexes is not observed for Fe³⁺, co²⁺,N²⁺,cu²⁺, or zn²⁺ under similar conditions.     

Methanol Selective Oxidation to Formaldehyde over Iron-Molybdate Catalysts

This review deals with the important industrial reaction of formaldehyde manufacture by methanol oxidation over iron molybdate catalysts. Detailed reference is made to the used catalyst, preparation techniques (coprecipitation, sol-gel like, mechanical mixing, etc.) including unsupported and supported catalysts, promoters and characterization methods. The controversial active phase assignment (stoichiometric versus Mo rich iron molybdate) is discussed. The proposed reaction mechanisms and kinetic laws for the main and side reactions are examined. The catalyst deactivation processes are reviewed and the role of Mo excess on these processes is underlined. Finally conclusions and perspectives are presented.     

Distribution of mono‐ and di‐methacrylic monomers in SBS block copolymer and its influence on the photopolymerization process

Persoz hardness measurements and the analysis of the temperature dependence of the storage modulus (E′) for SBS di‐ and tetrafunctional methacrylic monomer systems were carried out to determine the distribution of the monomers in the domains or phases of the SBS block copolymer, as well as the aggregation state of each system. The forces of attraction between the monomer and the phases or domains in the matrix (similar solubility parameters with appreciable dipole‐dipole and hydrogen bonding interactions) were determinant as for the monomer distribution. The influence of these structural factors on the kinetic parameters of the photoinitiated polymerization of di‐ and tetrafunctional methacrylic monomers in the SBS matrix was studied. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 163–168, 2005     

Polyurethane networks from formiated soy polyols: Synthesis and mechanical characterization

Polyurethanes can be prepared using polyols obtained from vegetable oils in natura, such as castor oil, or from functionalized vegetable oils, such as hydroxylated soybean oil. These polyurethanes have different valuable properties, determined by their chemical composition and cross-linking density. In this study, soy epoxy polyols with different OH contents were prepared through a one-step reaction using the method of in situ performic acid generation. Polyols with OH functionalities from 1.9 to 3.2 were reacted in bulk with different diisocyanates at a NCO/OH molar ratio of 0.8 and 60°C for 24 h. Mechanical properties of the polyurethanes were determined by dynamic mechanical thermal analysis, hardness (Shore A), and swelling measurements. Polymer networks with glass-transition temperatures (T _g ) from −13 to 48°C were obtained. We observed that the higher the OH functionality of the polyols, the higher the T _g and cross-linking density of the polyurethane network. The influence of diisocyanate structure (rigid or flexible chain), curing temperature, and curing reaction time on mechanical properties was also investigated.     

In Vivo Evaluation of Sgc8-c Aptamer as a Molecular Imaging Probe for Colon Cancer in a Mouse Xenograft Model

Recent biotechnological applications in the field of clinical oncology led to the identification of new biomarkers as molecular targets of cancer, and to broad developments in the field of personalized medicine. Aptamers are oligonucleotides (ssDNA or RNA) that are selected to specifically recognize a molecular target with high affinity and specificity. Based on this, new horizons for their use as molecular imaging probes are being explored. The objective of this work was to evaluate the Sgc8-c aptamer conjugated with Alexa Fluor 647 fluorophore as an imaging probe in a colon tumor xenograft mouse model, with potential application in molecular imaging. In this study, the LS174T cell line was used to induce colorectal adenocarcinoma in nude mice. After confirmation of PTK7 overexpression by immunohistochemistry, in vivo studies were performed. Pharmacokinetic, in vivo and ex vivo biodistribution imaging, and a competition assay were evaluated by fluorescence imaging. In vivo visualization of the probe in the tumors was assessed two hours after aptamer probe administration, exhibiting excellent tumor-to-background ratios in biodistribution studies and high specificity in the competition test. Our results demonstrated the functionality of Scg8-c as an imaging probe for colon cancer, with potential clinical applications.     

In Vitro Activity of Copper(II) Complexes,Loaded or Unloaded into a Nanostructured Lipid System,against Mycobacterium tuberculosis

Tuberculosis (TB) is an infectious disease caused mainly by the bacillus Mycobacterium tuberculosis (Mtb), presenting 9.5 million new cases and 1.5 million deaths in 2014. The aim of this study was to evaluate a nanostructured lipid system (NLS) composed of 10% phase oil (cholesterol), 10% surfactant (soy phosphatidylcholine, sodium oleate), and Eumulgin^® HRE 40 ([castor oil polyoxyl-40-hydrogenated] in a proportion of 3:6:8), and an 80% aqueous phase (phosphate buffer pH = 7.4) as a tactic to enhance the in vitro anti-Mtb activity of the copper(II) complexes [CuCl₂(INH)₂]·H₂O (1), [Cu(NCS)₂(INH)₂]·5H₂O (2) and [Cu(NCO)₂(INH)₂]·4H₂O (3). The Cu(II) complex-loaded NLS displayed sizes ranging from 169.5 ± 0.7095 to 211.1 ± 0.8963 nm, polydispersity index (PDI) varying from 0.135 ± 0.0130 to 0.236 ± 0.00100, and zeta potential ranging from −0.00690 ± 0.0896 to −8.43 ± 1.63 mV. Rheological analysis showed that the formulations behave as non-Newtonian fluids of the pseudoplastic and viscoelastic type. Antimycobacterial activities of the free complexes and NLS-loaded complexes against Mtb H₃₇Rv ATCC 27294 were evaluated by the REMA methodology, and the selectivity index (SI) was calculated using the cytotoxicity index (IC₅₀) against Vero (ATCC^® CCL-81), J774A.1 (ATCC^® TIB-67), and MRC-5 (ATCC^® CCL-171) cell lines. The data suggest that the incorporation of the complexes into NLS improved the inhibitory action against Mtb by 52-, 27-, and 4.7-fold and the SI values by 173-, 43-, and 7-fold for the compounds 1, 2 and 3, respectively. The incorporation of the complexes 1, 2 and 3 into the NLS also resulted in a significant decrease of toxicity towards an alternative model (Artemia salina L.). These findings suggest that the NLS may be considered as a platform for incorporation of metallic complexes aimed at the treatment of TB.     

Nanoliposomes for encapsulation and delivery of the potential antitumoral methyl 6-methoxy-3-(4-methoxyphenyl)-1H-indole-2-carboxylate

A potential antitumoral fluorescent indole derivative, methyl 6-methoxy-3-(4-methoxyphenyl)-1H-indole-2-carboxylate, was evaluated for the in vitro cell growth inhibition on three human tumor cell lines, MCF-7 (breast adenocarcinoma), A375-C5 (melanoma), and NCI-H460 (non-small cell lung cancer), after a continuous exposure of 48 h, exhibiting very low GI50 values for all the cell lines tested (0.25 to 0.33 μM). This compound was encapsulated in different nanosized liposome formulations, containing egg lecithin (Egg-PC), dipalmitoyl phosphatidylcholine (DPPC), dipalmitoyl phosphatidylglycerol (DPPG), DSPC, cholesterol, dihexadecyl phosphate, and DSPE-PEG. Dynamic light scattering measurements showed that nanoliposomes with the encapsulated compound are generally monodisperse and with hydrodynamic diameters lower than 120 nm, good stability and zeta potential values lower than -18 mV. Dialysis experiments allowed to monitor compound diffusion through the lipid membrane, from DPPC/DPPG donor liposomes to NBD-labelled lipid/DPPC/DPPG acceptor liposomes.     

Sinanodonta woodiana (mollusca: bivalvia: unionidae): isolation and characterization of the first microsatellite markers

Sinanodonta woodiana (Lea, 1834) is a large Unionid species with a real invasion success. It colonized Europe, Central America, the Indonesian Islands and recently North America. The species life cycle involves a larval parasitic stage on freshwater fish species which contributes to the spread of the mussel. In this paper we describe, for the first time, eight polymorphic microsatellite loci for the species Sinanodonta woodiana. The genetic screening of individuals confirmed that all loci were highly polymorphic. The number of alleles per locus ranged from 7 to 14 and the observed heterozygosity ranged from 0.650 to 0.950. These loci should prove useful to study the species population genetics which could help to infer important aspects of the invasion process.