This work deals with the preparation of chitosan/tripolyphosphate microparticles (CHT/TPP) using microemulsion system based on water/benzyl alcohol. The morphology of the microparticles was evaluated by scanning electron microscopy (SEM). The microparticles were also characterized through infrared spectroscopy (FTIR) and wide-angle X-ray scattering (WAXS). The morphology and crystallinity of microparticles depended mainly on CHT/TPP ratio. Studies of controlled release of HP were evaluated in distilled water and in simulated gastric fluid. Besides, the profile of HP releasing could be tailored by tuning the CHT/TPP molar ratio. Finally, these prospective results allow the particles to be employed as site-specific HP controlled release system.
Africa, Asia, and Latin America are regions highly affected by endemic diseases, such as Leishmaniasis, Malaria, and Chagas’ disease. They are responsible for the death of 1000s of patients every year, as there is not yet a cure for them and the drugs used are inefficient against the pathogenic parasites. During the life cycle of some parasitic protozoa, insects become the most important host and disseminator of the diseases triggered by these microorganisms. As infected insects do not develop nocive symptoms, they can carry the parasites for long time inside their body, enabling their multiplication and life cycle completion. Eventually, parasites infect human beings after insect’s transmission through their saliva and/or feces. Hence, host insects and general arthropods, which developed a way to coexist with such parasites, are a promising source for the prospection of anti-parasitic compounds, as alternative methods for the treatment of protozoa-related diseases. Among the molecules already isolated and investigated, there are proteins and peptides with high activity against parasites, able to inhibit parasite activity in different stages of development. Although, studies are still taking their first steps, initial results show new perspectives on the treatment of parasitic diseases. Therefore, in this report, we describe about peptides from host insect sources with activity against the three most endemic parasites: Leishmania sp., Plasmodium sp., and Trypanosomes. Moreover, we discuss the future application insect peptides as anti-parasitic drugs and the use of non-hosts insect transcriptomes on the prospection of novel molecules for the treatment of parasitic neglected diseases.
Here, the authors (i) discuss the most prominent co‐catalyst for H2 generation structured in the form of Me‐TiO2/MCM‐41 (Me: Ag, Co, Cu, Ni) based on structural, electronic, textural, morphological and optical characterization techniques, such as XRD, wide and small angle, XPS, Fourier‐transform infrared spectroscopy, scanning electron microscopy, B.E.T., textural analysis, photoacoustic spectroscopy and photoluminescence spectroscopy; and (ii) evaluate the difference in hydrogen production in two distinct geometric reactors based on a theoretical study of light distribution inside the reactors supported by the experimental quantum yield calculation. As a result, copper‐doped photocatalyst generated higher hydrogen amount compared to the others. The high photocatalyst performance was due to the greater lamp spectrum absorption, marked by the low bandgap value, and high photoactivity justified by the low rate of electronic recombination. The hydrogen generation in the quartz reactor was seven times higher than the annular one, and when at maximum light power, it is comparable to the most sophisticated reaction systems found in literature. The larger light exposure area per unit volume of the quartz reactor compared to the annular one is the reason why it obtained better results due to the lower emitted photon blockade, with a 1.81% apparent quantum yield.
This study aims to evaluate the effect of the grinding parameters applied to TiO2 comminution, which forms a heterojunction of anatase-rutile phases and reduces markedly the size particle. This material is a well-knowm photocatalyst in environmental issues such as degradation of synthetic dyes, mainly due to the large surface area and oxidative radicals generations ability. The influence of time, rotational speed and the solvent was investigated in the grinding process. Catalysts were prepared by a deposition method and were characterized by XRD, textural analysis (BET area), potential electrophoretic, photoacoustic and Mössbauer spectroscopy. The comminution procedure reduced the size of TiO2 crystallites from 87 nm to 22 nm as well as the surface area and pore diameter. The best photocatalytic activity was for TiO2 comminuted for 10 min and 300 rpm in a dry medium supported on ZSM-5. It was registered that the photoactivity of TiO2 decreased with the transition of anatase to rutile phase and also by the iron oxides insertion during the comminution process. This study has a great technologic contribution because it elucidates primary issues on the particle sizes reduction in the catalysts production, whose function is to have a better metal distribution on the support's surface.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.