Hydrolysis of the low gelatinization temperature Araucaria angustifolia pine seed starch

Journal of Thermal Analysis and Calorimetry - The effect of compressor speed, initial refrigerant charge and volume concentrations of SiO2/PAG nanolubricant on the performance of automotive...     

The viscoelasticity of thermotropic liquid crystalline polymers: effects of the chemical composition

In this work, the rheological properties of the wholly aromatic random copolyester HBA/HNA (60/40), the commercial copolyesteramide Vectra B950, and the semiflexible commercial copolyester Rodrun 3000, PET/HBA 40/60, were investigated. All the thermotropic liquid crystalline polymers (TLCPs) show linear viscoelastic behavior at small strain amplitudes. The strain sweep experiments have clearly indicated that the onset for non linearity significantly decreases as the applied frequency increases in all the TLCPs here studied, independent of chemical composition and flexibility. In the case of the Vectra B950, a strain-hardening effect occurred at a strain of about 40% for all the applied frequencies. The frequency behavior showed that the HBA/HNA 60/40 TLCP is characterized by the leveling off of G′ and by a dominant elastic behavior at low frequencies. The inclusion of the flexible PET determines the disappearance of the plateau value for G′ with a viscous response at low frequencies.Paper presented at the Annual Meeting of the European Society of Rheology, Grenoble, April 2005.     

Assessment of a pioneer metabolic information service in Brazil

The Information Service on Inborn Errors of Metabolism (SIEM), a pioneer toll-free service in both Brazil and South America, is based in Porto Alegre, Southern Brazil. SIEM has been operating since October 2001 providing support to health care professionals involved in the diagnosis and management of suspected metabolic diseases. We analyzed the demographic and clinical characteristics of the 376 consults received and followed in the first two and half years of SIEM. Our results show that the suspicion of a metabolic disease was most often associated with neurological symptoms. Among the consults, 24.4% were eventually confirmed as inborn errors of metabolism (IEM), with organic acidurias and amino acid disorders being the two most frequent diagnostic groups. Our conclusion shows this kind of service to provide helpful support to the diagnosis and acute management of IEM, especially to health professionals working in developing countries who are often far from reference centers.     

Synthesis and Biological Evaluation of Amidinourea Derivatives against Herpes Simplex Viruses

Current therapy against herpes simplex viruses (HSV) relies on the use of a few nucleoside antivirals such as acyclovir, famciclovir and valacyclovir. However, the current drugs are ineffective against latent and drug-resistant HSV infections. A series of amidinourea compounds, designed as analogues of the antiviral drug moroxydine, has been synthesized and evaluated as potential non-nucleoside anti-HSV agents. Three compounds showed micromolar activity against HSV-1 and low cytotoxicity, turning to be promising candidates for future optimization. Preliminary mode of action studies revealed that the new compounds act in an early stage of the HSV replication cycle, just after the viral attachment and the entry phase of the infection.     

Model based soft-sensor for on-line determination of substrate

A software sensor for on-line determination of substrate was developed based on a model for fed-batch alcoholic fermentation process and on-line measured signals of ethanol, biomass, and feed flow. The ethanol and biomass signals were obtained using a colorimetric biosensor and an optical sensor developed in previous works that permitted determination of ethanol at a concentration of 0–40 g/L and biomass of 0–60 g/L. The volume in the fermentor could be continuously calculated using the total measured signal of the feed flow. The results obtained show that the model used is adequate for the proposed software sensor and determines continuously the substrate concentration with efficiency and security during the fermentation process.     

The bidimensional interproximation problem and mixed splines

Interproximation methods for surfaces can be used to construct a smooth surface interpolating some data points and passing through specified regions. In this paper we study the use of mixed splines, that is smoothing splines with additional interpolation constraints, to solve the interproximation problem for surfaces in the case of scattered data. The solution is obtained by solving a linear system whose structure can be improved by using “bell-shaped” thin plate splines.     

Expanding the Scope of Atropisomeric Monodentate P‐Donor Ligands in Asymmetric Catalysis: Hydrogen‐Transfer Reduction of α,β‐Unsaturated Acid Derivatives by Rhodium/Ph‐binepine Catalysts

A range of α,β‐unsaturated acids and esters have been selectively reduced to the corresponding saturated acid derivatives by hydrogen transfer. As the reducing agent, formic acid was used in the presence of Rh^I complexes formed with the powerful chiral ligand Ph‐binepine ( 1 ), an axially chiral binaphthalene‐type monodentate P‐donor ligand. Very high stereoselectivities (up to 97% ee) were obtained in the case of itaconic acid ( 2a ).     

Ab initio molecular electrostatic potentials

The ab initio isopotential map of guanine is given and compared to that of adenine. It shows that in contrast to the situation in adenine, the most basic site of guanine is N₇ with a secondary potential minimum at O₆. These results as well as those concerning the secondary out-of-plane attractive regions over the NH₂ group and C₈ H bonds of the two molecules are discussed in connection with the available experimental knowledge concerning the bonding of alkylating carcinogens and mutagens.     

Infrared studies of small azobenzene peptides: unexpectedly slow reactions on the time range of minutes

Infrared absorption experiments on light-triggered azobenzene peptides have been performed below and above the freezing point of the solvent dimethyl sulfoxide (DMSO). Even 20 K below the freezing point, illumination of the azobenzene chromophore resulted in IR absorption changes indicative of light-induced structural rearrangements of the peptide. In addition, new conformational states could be found at low temperature, which involve the formation of additional hydrogen bonds. In one sample the new low-temperature state survived melting and reheating and disappeared at 298 K only on the time scale of 10 min. The observations indicate that at low temperatures the peptide, together with traces of water present in the sample, forms a shell in the vicinity of the chromophore that facilitates internal motion even in the rigid cage of frozen DMSO.     

Biochemical characterization of an in-house Coccidioides antigen: perspectives for the immunodiagnosis of coccidioidomycosis

The objective of this study was to evaluate the reactivity of an in-house antigen, extracted from a strain of C. posadasii isolated in northeastern Brazil, by radial immunodiffusion and Western blotting, as well as to establish its biochemical characterization. The protein antigen was initially extracted with the use of solid ammonium sulfate and characterized by 1-D electrophoresis. Subsequently, it was tested by means of double radial immunodiffusion and Western blotting. A positive reaction was observed against the antigen by both immunodiagnostic techniques tested on sera from patients suffering from coccidioidomycosis. Besides this, two immunoreactive protein bands were observed and were revealed to be a β-glucosidase and a glutamine synthetase after sequencing of the respective N-terminal regions. Our in-house Coccidioides antigen can be promising as a quick and low-cost diagnostic tool without the risk of direct manipulation of the microorganism.