Hélio Barros

• PhD
• Researcher at University of Lisbon

Novel benzazole derivatives were synthesized and their photophysical properties were determined experimentally in different types of solvents also by theoretical calculations using Density Functional Theory (DFT). The results of the theoretical computational studies were well consistent with those observed experimentally, evidencing the type of ele...

Luminescent Down-Shifting (LDS) is an optical approach applied in several photovoltaic (PV) technologies in which high energy solar radiation is converted to a wavelength region where the response of the photovoltaic devices is better. The use of LDS layers on organic photovoltaics (OPV) could serve two purposes: to prevent cell degradation by filt...

Detection and visualization of latent fingermarks are research areas that have been extensively explored over the years, mainly in the search for new methods and to improve existing fingermark developers. The aim of the present study was to propose new fingermark developers in an attempt to improve existing methods, especially regarding characteris...

Benzazole dyes have shown great potential for application in different fields of science due to their intense and stable photoluminescence properties, associated with high sensitivity. In this study, we developed and evaluated micro-structured fluorescent powders based on benzazole dyes for fingerprint detection on different types (porous and non-p...

Bloodstains are the most common and useful type of physical evidence in crime investigation. The detection and examination of bloodstains are of great value in the reconstruction of a crime scene and linking a criminal or the victim with the crime scene. There is a wide variety of chemicals available for detecting bloodstains and enhancing bloody f...

Lung cancer ranks as the predominant cause of cancer-related mortalities on a global scale. Despite progress in therapeutic interventions, encompassing surgical procedures, radiation, chemotherapy, targeted therapies and immunotherapy, the overall prognosis remains unfavorable. Imbalances in redox equilibrium and disrupted redox signaling, common t...

Pyrene molecule, with excellent photophysical properties (strong absorption cross section, excellent emission properties and a long-excited state lifetime), excellent thermal and photochemical stability, has been widely used as a building block for the synthesis of pyrene-based fluorophores for optoelectronic applications. In this work, we report t...

Essential oils (EOs) contain different types of chemical compounds such as alkaloids, isoflavones, flavonoids, monoterpenes, carotenoids, phenolic acids, and aldehydes with biological properties. However, when exposed to harsh environmental conditions, these compounds can become chemically unstable and susceptible to degradation, volatilization, an...

Recently, studies on natural products have considerably increased due to their exceptional biological activities and health benefits. Subsequently, their pharmacological attributes have played an immense role in detecting natural and safe alternative therapeutics extending, consequently, their industrial applications. In this line, ginger (Zingiber...

High-throughput screening methodologies to estimate lipid content in oleaginous yeasts use Nile red fluorescence in a given solvent and optimized excitation/emission wavelengths. However, Nile red fluorescence stabilization has been poorly analyzed, and high variability occurs when relative fluorescence is measured immediately or a few minutes afte...

We used Nile red to estimate lipid content in oleaginous yeasts using a high-throughput approach. We measured the fluorescence intensity of Nile red using different solvents, yeast strains, and incubation times in optimized excitation/emission wavelengths. The data show the relative fluorescence units (RFU) for Nile red excitation, using 1× PBS, 1×...

The aim of this study was to encapsulate garlic extract by complex coacervation method using whey protein isolate (WPI)/chitosan (CH) and gum Arabic (GA)/CH as wall materials. Two anionic biopolymers (GA and WPI) were used to find the most suitable wall materials to interact electrostatically with cationic CH. The complex coacervates were freeze-dr...

A series of four water-soluble benzazole dyes that emit fluorescence by the excited state intramolecular proton transfer (ESIPT) mechanism were structurally characterized by Fourier transform infrared spectroscopy (FTIR), 1H and 13C nuclear magnetic resonance (NMR) attached proton test (APT) and mass spectrometry. Their photophysical properties wer...

Este estudo mostra o corante fluorescente 4-hidroxi-3- (6-metilbenzo[d]oxazol-2-il) benzeno sulfônico (HB-9) marcando, por microscopia de fluorescência, ovos de helmintos e oocistos de protozoários diagnosticados em animais domésticos. Foram selecionados ovos de Acuaria spiralis, Strongyloides papillosus, Capillaria spp., Bertiella spp., Strongyloi...

This study presents a new method for visualization of Oxyuris equi eggs collected by means of a clear adhesive tape applied to the perianal region of horses. The obtained results indicate that this protocol permits a quick, easy, clear and selective visualization of Oxyuris equi eggs even in the presence of feces and other material. Another advanta...

Three novel fluorescent dyes were evaluated for the detection of latent fingermarks on different types and colors of adhesive tapes. Compared with the conventional reagents used to reveal latent fingermarks on these surfaces, these new fluorescent dyes have many advantages. They are highly selective to fingermarks, require only a simple procedure,...

A presente invenção descreve a obtenção de derivados benzazólicos fluorescentes que propiciem o mecanismo de transferência protônica intramolecular no estado excitado (ESIPT), bem como sua caracterização e sua aplicação como reveladores de impressões digitais latentes em fitas adesivas de diversas cores e outras superfícies de interesse forense, ta...