Red Mud from Brazil: Thermal Behavior and Physical Properties

The main constituents of red mud produced in Aluminio city (S.P., Brazil) are iron, aluminum, and silicon oxides. It has been determined that the average particle diameter for this red mud is between 0.05 and 0.002 mm. It is observed that a decrease in the percentage of smaller particles occurs at temperatures greater than 400 degrees C. This observation corresponds with the thermal analysis and X-ray diffraction (XRD) data, which illustrate the phase transition of goethite to hematite. A 10% mass loss is observed in the thermal analysis patterns due to the hydroxide-oxide phase transitions of iron (primary phase transition) and aluminum (to a lesser extent). The disappearance and appearance of the different phases of iron and aluminum confirms the decomposition reactions proposed by the thermal analysis data. This Brazilian red mud has been classified as mesoporous at all temperatures except between 400 and 500 degrees C where the classification changes to micro/mesoporous.

Non-classical HLA-E gene variability in Brazilians: a nearly invariable locus surrounded by the most variable genes in the human genome

The non-classical human leukocyte antigen (HLA) class I genes present a very low rate of variation. So far, only 10 HLA-E alleles encoding three proteins have been described, but only two are frequently found in worldwide populations. Because of its historical background, Brazilians are very suitable for population genetic studies. Therefore, 104 bone marrow donors from Brazil were evaluated for HLA-E exons 14. Seven variation sites were found, including two known single nucleotide polymorphisms (SNPs) at positions +424 and +756 and five new SNPs at positions +170 (intron 1), +1294 (intron 3), +1625, +1645 and +1857 (exon 4). Haplotyping analysis did show eight haplotypes, three of them known as E*01:01:01, E*01:03:01 and E*01:03:02:01 and five HLA-E new alleles that carry the new variation sites. The HLA-E*01:01:01 allele was the predominant haplotype (62.50%), followed by E*01:03:02:01 (24.52%). Selective neutrality tests have disclosed an interesting pattern of selective pressures in which balancing selection is probably shaping allele frequency distributions at an SNP at exon 3 (codon 107), sequence diversity at exon 4 and the non-coding regions is facing significant purifying pressure. Even in an admixed population such as the Brazilian one, the HLA-E locus is very conserved, presenting few polymorphic SNPs in the coding region.

Riemannian Submersions with Discrete Spectrum

We prove some estimates on the spectrum of the Laplacian of the total space of a Riemannian submersion in terms of the spectrum of the Laplacian of the base and the geometry of the fibers. When the fibers of the submersions are compact and minimal, we prove that the spectrum of the Laplacian of the total space is discrete if and only if the spectrum of the Laplacian of the base is discrete. When the fibers are not minimal, we prove a discreteness criterion for the total space in terms of the relative growth of the mean curvature of the fibers and the mean curvature of the geodesic spheres in the base. We discuss in particular the case of warped products.

Determination of the activation energies of beef tallow and crude glycerin combustion using thermogravimetry

The present study deals with the determination of the activation energy for the thermal decomposition of two renewable fuels crude glycerin and beef tallow. The activation energies were investigated by using a thermogravimetric analyzer (TGA) in the temperature range of 25-600 degrees C in atmosphere of synthetic air. The TG curves of the thermal decomposition process of both samples were divided into several phases and the second, called PH2, was chosen for the kinetic study because it is associated with the combustion ignition. Differential Thermal Analysis (DTA) showed an endothermic event at the PH2 region for the crude glycerin corresponding to devolatilization, while for beef tallow, this step presented an exothermic event, called LTO (low-temperature oxidation), which is correlated with devolatilization followed by combustion. For the entire PH2, activation energy values for crude glycerin were between 90 kJ mol(-1) and 42 kJ mol(-1), while for the beef tallow they ranged from 50 kJ mol(-1) to 113 kJ mol (1). The activation energy values obtained at the pre-ignition stage - conversion between 0 and 0.45 - showed that the crude glycerin with higher values requires an additional energetic support at the start of combustion processes and the beef tallow ignites more easily, presenting lower values. According to the Wolfer's equation, a direct relation between the activation energy and the ignition delay is established and the results of this study provides useful data for the development and design of new combustion chambers and engines when non-traditional fuels are used as feedstock. (C) 2012 Elsevier Ltd. All rights reserved.

Terbium(III) and dysprosium(III) 8-connected 3D networks containing 2,5-thiophenedicarboxylate anion: Crystal structures and photoluminescence studies

Two novel coordination polymers with the formula {[Ln(2)(2,5-tdc)(3)(dmso)(2)].H2O}(n) (Ln = Tb(III) for (1) and Dy(III) for (2)), (2,5-tdc(2-) = 2,5-thiophenedicarboxylate and dmso = dimethylsulfoxide) have been synthesized by the diffusion method and characterized by thermal analysis, vibrational spectroscopy and single crystal X-ray diffraction analysis. Structure analysis reveals that 2,5-tdc(2-) play a versatile role toward different lanthanide ions to form three-dimensional metal-organic frameworks (MOFs) in which the lanthanides ions are heptacoordinated. Photophysical properties were studied using excitation and emission spectra, where the photoluminescence data show the high emission intensity of the characteristic transitions D-5(4 ->) F-7(J) (J= 6, 5, 4 and 3) for (1) and (F9/2 -> HJ)-F-4-H-6 (J = 15/2, 13/2 and 11/2) for (2), indicating that 2,5-tdc(2-) is a good sensitizer. (C) 2012 Elsevier Ltd. All rights reserved.

Interaction of p-cymene with beta-cyclodextrin

In this investigation, the study of inclusion complexes formation between p-cymene and beta-cyclodextrin using the methods of physical mixture, paste (PC) and slurry (SC), was evaluated. The results of DSC and TG/DTG showed that the products prepared by PC and SC methods were able to incorporate greater amounts of p-cymene, as evidenced by the weight loss of 7.15 and 3.97%, respectively, which occurred between 120 and 270 A degrees C. SEM images showed decreased size of the household, especially in the SC product. The absorption bands in the IR spectrum, characteristic of p-cymene, were also identified in the preparations, indicating the presence of the compound in the complex.

Thermal Analysis and Raman Spectra of Different Phases of the Ionic Liquid Butyltrimethylammonium Bis(trifluoromethylsulfonyl)imide

The ionic liquid butyltrimethylammonium bis(trifluoromethylsulfonyl)imide, [C4C1C1C1N][Tf2N], is a glass-forming liquid that exhibits partial crystallization depending on the cooling rate. Differential scanning calorimetry (DSC) indicates crystallization at T-c = 227 K, melting at T-m = 258 K, glass transition at T-g similar to 191 K, and also cold crystallization at T-cc similar to 219 K. Raman spectroscopy shows that the crystalline structure obtained by slow cooling is formed with [Tf2N](-) in cisoid conformation, whereas [Tf2N](-) in transoid conformation results from fast cooling. No preferred conformation of the butyl chain of the [C4C1C1C1N](+) cation is favored by slow or fast cooling of [C4C1C1C1N][Tf2N]. Low-frequency Raman spectroscopy shows that crystalline domains developing in the supercooled liquid result in a glacial state made of a mixture of crystallites and amorphous phase. However, these crystalline structures obtained by slow cooling or cold crystallization are not the same because anion-cation interactions promote local structures with distinct conformations of the [Tf2N](-) anion.

DETERMINATION OF DICLOFENAC SODIUM IN RABBIT PLASMA BY HPLC/UV: EVALUATION AND CHARACTERIZATION OF ITS CRYSTALLINE FORMS, ANHYDROUS AND HYDRATE, ON THE ANTIPYRETIC EFFECT

Diclofenac sodium (DS) is a non-steroidal anti-inflammatory drug that is widely prescribed for the treatment of rheumatoid arthritis and post-surgery analgesia. The active pharmaceutical ingredient is the anhydrous form; however, it can also exist in hydrate form. In this context, knowing the properties of the solid state is important and relevant in the pharmaceutical area because they have a significant impact on the solubility, bioavailability, and chemical stability of the drugs. In the present study, data from XRPD, FTIR spectroscopy, and thermal analysis were used for the identification and characterization of DS forms (anhydrous and hydrate). An HPLC method was optimized to evaluate the plasma concentration of DS in rabbits. The optimized method exhibited good linearity over the range 0.1-60 mu g/mL with correlation coefficients of >0.9991. The mean recovery was 100%. Precision and accuracy were determined within acceptable limits. Finally, to compare the pharmacological properties of anhydrous and hydrate DS forms, we investigated their effects in the febrile response induced by lipopolysaccharide from E. coli in rabbits. The results show that the antipyretic effect of anhydrous and hydrate DS forms are similar.

Structure- and ligand-based drug design approaches for neglected tropical diseases

Drug discovery has moved toward more rational strategies based on our increasing understanding of the fundamental principles of protein-ligand interactions. Structure( SBDD) and ligand-based drug design (LBDD) approaches bring together the most powerful concepts in modern chemistry and biology, linking medicinal chemistry with structural biology. The definition and assessment of both chemical and biological space have revitalized the importance of exploring the intrinsic complementary nature of experimental and computational methods in drug design. Major challenges in this field include the identification of promising hits and the development of high-quality leads for further development into clinical candidates. It becomes particularly important in the case of neglected tropical diseases (NTDs) that affect disproportionately poor people living in rural and remote regions worldwide, and for which there is an insufficient number of new chemical entities being evaluated owing to the lack of innovation and R&D investment by the pharmaceutical industry. This perspective paper outlines the utility and applications of SBDD and LBDD approaches for the identification and design of new small-molecule agents for NTDs.

A dry extract of Phyllanthus niruri protects normal cells and induces apoptosis in human liver carcinoma cells

The ability to induce apoptosis is an important marker for cytotoxic antitumor agents. Some natural compounds have been shown to modulate apoptosis pathways that are frequently blocked in human cancers, and therefore, these compounds provide novel opportunities for cancer drug development. Phyllanthus, a plant genus of the family Euphorbiaceae, exhibits multiple pharmacological actions. Of these, Phyllanthus niruri extracts exhibit significant antitumor activity, which is consistent with the traditional medicinal use of this plant. To examine the apoptotic effects of a spray-dried extract of P. niruri (SDEPN), human hepatocellular carcinoma cells (HepG2, Huh-7), colorectal carcinoma cells (Ht29) and keratinocytes (HaCaT) were exposed to the extract for 4, 8 and 24 h. Flow cytometry and caspase-3 immunostaining were used to detect apoptosis, while analysis of variance was applied to identify significant differences between groups (P < 0.05). At all timepoints, the SDEPN induced significantly different cytotoxic effects for HepG2 and Huh-7 cells compared with control cells (P < 0.001). In contrast, the SDEPN had a protective effect on HaCaT cells compared with control cells at all timepoints (P < 0.001). In caspase-3 assays, activation was detected after cell death was induced in Huh-7 and HepG2 cancer cells by the SDEPN. In combination, these results indicate that the SDEPN is selectively toxic towards cancer cell lines, yet is protective towards normal cells.

Synthesis and characterization of CeO2-graphene composite

The synthesis and characterization of graphite oxide (GO), graphene (GS), and the composites: GS-CeO2 and GO-CeO2 are reported. This synthesis was carried out by mixing aqueous solutions of CeCl3 center dot 7H(2)O and GO, which yields the oxidized composite GO-CeO2. GO-CeO2 was hydrothermally reduced with ethylene glycol, at 120 A degrees C, yielding the reduced composite GS-CeO2. GO, GS ,and the composites with CeO2 were characterized by CHN, TG/DTG, BET, XRD, SEM microscopy, FTIR, and Raman spectroscopy. The estimation of crystallite size of CeO2 anchored on GO and on GS by Raman, XRD, and SEM agreed very well showing diameters about 5 nm. The role of particles of CeO2 coating carbon sheets of GO and GS was discussed.

Duplications of BHLHA9 are associated with ectrodactyly and tibia hemimelia inherited in non-Mendelian fashion

Background Split-hand/foot malformation (SHFM)-also known as ectrodactyly-is a congenital disorder characterised by severe malformations of the distal limbs affecting the central rays of hands and/or feet. A distinct entity termed SHFLD presents with SHFM and long bone deficiency. Mouse models suggest that a defect of the central apical ectodermal ridge leads to the phenotype. Although six different loci/mutations (SHFM1-6) have been associated with SHFM, the underlying cause in a large number of cases is still unresolved. Methods High resolution array comparative genomic hybridisation (CGH) was performed in patients with SHFLD to detect copy number changes. Candidate genes were further evaluated for expression and function during limb development by whole mount in situ hybridisation and morpholino knock-down experiments. Results Array CGH showed microduplications on chromosome 17p13.3, a locus previously associated with SHFLD. Detailed analysis of 17 families revealed that this copy number variation serves as a susceptibility factor for a highly variable phenotype with reduced penetrance, particularly in females. Compared to other known causes for SHFLD 17p duplications appear to be the most frequent cause of SHFLD. A similar to 11.8 kb minimal critical region was identified encompassing a single gene, BHLHA9, a putative basic loop helix transcription factor. Whole mount in situ hybridisation showed expression restricted to the limb bud mesenchyme underlying the apical ectodermal ridge in mouse and zebrafish embryos. Knock down of bhlha9 in zebrafish resulted in shortening of the pectoral fins. Conclusions Genomic duplications encompassing BHLHA9 are associated with SHFLD and non-Mendelian inheritance characterised by a high degree of non-penetrance with sex bias. Knock-down of bhlha9 in zebrafish causes severe reduction defects of the pectoral fin, indicating a role for this gene in limb development.

Natural Membranes for Application in Biomedical Devices

Polymers from natural sources are particularly useful as biomaterials for medical devices applications. In this study, the results of characterization of a gelatin network electrolyte doped with europium triflate (Eu(CF3SO3)(3)) are described. The unusual electronic properties of the trivalent lanthanide ions make them well suited as luminescent reporter groups, with many applications in biotechnology. Samples of solvent-free electrolytes were prepared with a range of guest salt concentration. Materials based on Eu(CF3SO3)(3) were obtained as mechanically robust, flexible, transparent, and completely amorphous films. Samples were characterized by thermal analysis (thermo-gravimetry analysis (TGA) and differential scanning calorimetry (DSC), electrochemical stability, scanning electronmicroscopy (SEM), and photoluminescence spectroscopy.

Quantification of Short and Medium Range Order in Mixed Network Former Glasses of the System GeO2-NaPO3: A Combined NMR and X-ray Photoelectron Spectroscopy Study

Glasses in the system xGeO(2)-(1-x)NaPO3 (0 <= x <= 0.50) were prepared by conventional melting quenching and characterized by thermal analysis, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and P-31 nuclear magnetic resonance (MAS NMR) techniques. The deconvolution of the latter spectra was aided by homonuclear J-resolved and refocused INADEQUATE techniques. The combined analyses of P-31 MAS NMR and O-1s XPS lineshapes, taking charge and mass balance considerations into account, yield the detailed quantitative speciations of the phosphorus, germanium, and oxygen atoms and their respective connectivities. An internally consistent description is possible without invoking the formation of higher-coordinated germanium species in these glasses, in agreement with experimental evidence in the literature. The structure can be regarded, to a first approximation, as a network consisting of P-(2) and P-(3) tetrahedra linked via four-coordinate germanium. As implied by the appearance of P-(3) units, there is a moderate extent of network modifier sharing between phosphate and germanate network formers, as expressed by the formal melt reaction P-(2) + Ge-(4) -> P-(3) + Ge-(3). The equilibrium constant of this reaction is estimated as K = 0.52 +/- 0.11, indicating a preferential attraction of network modifier by the phosphorus component. These conclusions are qualitatively supported by Raman spectroscopy as well as P-31{Na-23} and P-31{Na-23} rotational echo double resonance (REDOR) NMR results. The combined interpretation of O-1s XPS and P-31 MAS NMR spectra shows further that there are clear deviations from a random connectivity scenario: heteroatomic P-O-Ge linkages are favored over homoatomic P-O-P and Ge-O-Ge linkages.

Influence of Alloying Elements Upon the Solidification Interval of CA6NM Cast Martensitic Stainless Steel

The influence of different Cr and C contents upon the solidification interval of ASTM A352M-06 Grade CA6NM cast martensitic stainless steel has been investigated using computational thermodynamics, and checked against DTA measurements in samples taken from 13 large cast parts, in order to identify potential sources for improvement on the part castability. Calculation results suggest, indeed, that this would be the case for C: when its content increases from 0.018 to 0.044 wt.% C (within the allowed range in the alloy specification), the solidification intervals increases from 25 to 43 K, which suggests improved castability with decreasing C contents. DTA results, however, do not support this prediction, showing a fairly constant solidification interval around 23 K for all investigated samples. The results are discussed both regarding the impact in alloy processing and the fitness of the existing databases to reproduce experimental results in these limiting cases.