Publications by authors named "Heron D T da Silva"

Polyamines are low molecular weight compounds that are present in all living organisms. They are related to the pathological processes, and have been studied as biomarkers for tumor progression, being analyzed in patients' biological fluids. However, polyamines can undergo degradation in serum samples, depending on storage conditions, which impairs their quantification in these matrices.

View Article and Find Full Text PDF
Article Synopsis
  • Cri du Chat syndrome is a genetic disorder caused by a deletion on the short arm of chromosome 5, affecting about 1 in 50,000 individuals globally.
  • A study analyzed urine samples from individuals aged 1-38 with the syndrome using advanced techniques like ultra-performance liquid chromatography and mass spectrometry.
  • The findings revealed changes in certain amino acids and biogenics, indicating disruptions in metabolic pathways related to energy recovery and glycolysis in patients with Cri du Chat syndrome.
View Article and Find Full Text PDF

Yeast biomass from ethanol industry (YB) was evaluated as a biosorbent to 17α-ethinylestradiol (EE) alone and along with estrone (EST). This material is rich in sorption sites and has a good cost-benefit ratio, since it is an industrial residue largely produced (around 30 g for each liter of ethanol). A 2-factorial design was carried out to evaluate the sorption capacity of YB for EE considering the variables pH, biosorbent dose (BD), and ionic strength (IS), at two hormone concentration (HC) levels.

View Article and Find Full Text PDF

Oil spill is a serious environmental concern, and alternatives to remove oils from water involving biosorbents associated to nanoparticles is an emerging subject. Magnetite nanoparticles (MNP) and yeast magnetic bionanocomposite (YB-MNP) composed by yeast biomass from the ethanol industry were produced, characterized, and tested to remove new motor oil (NMO), mixed used motor oil (MUMO) and Petroleum 28 °API (P28API) from water following the ASTM F726-12 method, which was adapted by insertion of a lyophilization step to ensure the accuracy of the gravimetric approach. Temperature, contact time, the type and the amount of the magnetic material were the parameters evaluated employing a fractional factorial design.

View Article and Find Full Text PDF

Diacetyl is a flavoring that imparts a buttery flavor to foods, but the use or exposure to diacetyl has been related to some diseases. We investigated the effect of oral intake of diacetyl in male and female C57/Bl mice. We performed a target metabolomics assay using ultraperformance liquid chromatography paired with triple quadrupole mass spectrometry (UPLC-MS/MS) for the determination and quantification of plasmatic metabolites.

View Article and Find Full Text PDF

Cri-du-chat syndrome (CDCS) is a rare innate disease attributed to chromosome 5p deletion characterized by a cat-like cry, craniofacial malformation, and altered behavior of affected children. Metabolomic analysis and a chemometric approach allow description of the metabolic profile of CDCS as compared to normal subjects. In the present work, UHPLC/MS was employed to analyze blood samples withdrawn from CDCS carriers (n=18) and normal parental subjects (n=18), all aged 0-34 years, aiming to set up a representative CDCS profile constructed from 33 targeted amino acids and biogenic amines.

View Article and Find Full Text PDF

The application of Design of Experiments (DoE) to the determination of optimum conditions for an extraction process relies on the correct selection of mathematical models. The linear model is the one typically used; however, in some cases it does not always have superior performance, ignoring the real nature of the data and its appropriate descriptive model. In order to evaluate the extraction efficiency of isorhamnetin-3-O-rutinoside from flowers of Calendula officinalis L.

View Article and Find Full Text PDF

We describe the development of an electrophoresis microchip fabricated by a direct-printing process, based on lamination of printed polyester films with end-channel amperometric detection. The channel structures are defined by polyester (base and cover) and by a toner layer (walls). The polyester-toner devices presented an electroosmotic flow (EOF) magnitude of approximately 10(-5) cm2 V(-1) s(-1), which is generated by a polymeric mixture of the toner and polyester composition.

View Article and Find Full Text PDF

A new process for the manufacture of microfluidic devices based on deposition of laser-printing toner on glass substrates is described. It is an alternative method to the toner on polyester film (toner-polyester) one, previously introduced. Commercial laser printers cannot print directly on glass, thus the toner must first be printed on a special paper and then transferred by heating under pressure to the glass surface.

View Article and Find Full Text PDF

A new microfabrication process based on a xerographic process is described. A laser printer is used to selectively deposit toner on a polyester film, which is subsequently laminated against another polyester film. The toner layer binds the two polyester films and allows the blank regions to become channels for microfluidics.

View Article and Find Full Text PDF