We computed a comprehensive set of theoretical ultraviolet spectra of hot, massive stars with the radiation-hydrodynamics code WM-Basic. This model atmosphere and spectral synthesis code is optimized ...for computing the strong P Cygni type lines originating in the winds of hot stars, which are the strongest features in the ultraviolet spectral region. The computed set is suitable as a spectral library for inclusion in evolutionary synthesis models of star clusters and star-forming galaxies. The chosen stellar parameters cover the upper left Hertzsprung-Russell diagram at L {approx}> 10{sup 2.75} L {sub sun} and T {sub eff} {approx}> 20,000 K. The adopted elemental abundances are 0.05 Z {sub sun}, 0.2 Z {sub sun}, 0.4 Z {sub sun}, Z {sub sun}, and 2 Z {sub sun}. The spectra cover the wavelength range from 900 to 3000 A and have a resolution of 0.4 A. We compared the theoretical spectra to data of individual hot stars in the Galaxy and the Magellanic Clouds obtained with the International Ultraviolet Explorer and Far Ultraviolet Spectroscopic Explorer satellites and found very good agreement. We built a library with the set of spectra and implemented it into the evolutionary synthesis code Starburst99 where it complements and extends the existing empirical library toward lower chemical abundances. Comparison of population synthesis models at solar and near-solar composition demonstrates consistency between synthetic spectra generated with either library. We discuss the potential of the new library for the interpretation of the rest-frame ultraviolet spectra of star-forming galaxies. Properties that can be addressed with the models include ages, initial mass function, and heavy-element abundance. The library can be obtained both individually or as part of the Starburst99 package.
Photocatalytic nanoparticles offer antimicrobial effects under illumination due to the formation of reactive oxygen species (ROS), capable of degrading bacterial membranes. ROS may, however, also ...degrade human cell membranes and trigger toxicity. Since antimicrobial peptides (AMPs) may display excellent selectivity between human cells and bacteria, these may offer opportunities to effectively “target” nanoparticles to bacterial membranes for increased selectivity. Investigating this, photocatalytic TiO2 nanoparticles (NPs) are coated with the AMP LL‐37, and ROS generation is found by C11‐BODIPY to be essentially unaffected after AMP coating. Furthermore, peptide‐coated TiO2 NPs retain their positive ζ‐potential also after 1–2 h of UV illumination, showing peptide degradation to be sufficiently limited to allow peptide‐mediated targeting. In line with this, quartz crystal microbalance measurements show peptide coating to promote membrane binding of TiO2 NPs, particularly so for bacteria‐like anionic and cholesterol‐void membranes. As a result, membrane degradation during illumination is strongly promoted for such membranes, but not so for mammalian‐like membranes. The mechanisms of these effects are elucidated by neutron reflectometry. Analogously, LL‐37 coating promoted membrane rupture by TiO2 NPs for Gram‐negative and Gram‐positive bacteria, but not for human monocytes. These findings demonstrate that AMP coating may selectively boost the antimicrobial effects of photocatalytic NPs.
Mirroring the selectivity of antimicrobial peptides in solution, coating photocatalytic TiO2 nanoparticles (NPs) with such peptides allows targeting of bacteria‐like membranes. On UV illumination, peptide‐coated NPs potently generate reactive oxygen species, which degrade bacteria‐like membranes, but much less so mammalian‐like ones. Demonstrating the biological relevance of this, peptide‐coated TiO2 NPs display potent effects against bacteria, but low toxicity toward human monocytes.
In the present study, we investigated lipid membrane interactions of silica nanoparticles as carriers for the antimicrobial peptide LL-37 (LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES). In doing so, ...smooth mesoporous nanoparticles were compared to virus-like mesoporous nanoparticles, characterized by a “spiky” external surface, as well as to nonporous silica nanoparticles. For this, we employed a combination of neutron reflectometry, ellipsometry, dynamic light scattering, and ζ-potential measurements for studies of bacteria-mimicking bilayers formed by palmitoyloleoylphosphatidylcholine/palmitoyloleoylphosphatidylglycerol. The results show that nanoparticle topography strongly influences membrane binding and destabilization. We found that virus-like particles are able to destabilize such lipid membranes, whereas the corresponding smooth silica nanoparticles are not. This effect of particle spikes becomes further accentuated after loading of such particles with LL-37. Thus, peptide-loaded virus-like nanoparticles displayed more pronounced membrane disruption than either peptide-loaded smooth nanoparticles or free LL-37. The structural basis of this was clarified by neutron reflectometry, demonstrating that the virus-like nanoparticles induce trans-membrane defects and promote incorporation of LL-37 throughout both bilayer leaflets. The relevance of such effects of particle spikes for bacterial membrane rupture was further demonstrated by confocal microscopy and live/dead assays on Escherichia coli bacteria. Taken together, these findings demonstrate that topography influences the interaction of nanoparticles with bacteria-mimicking lipid bilayers, both in the absence and presence of antimicrobial peptides, as well as with bacteria. The results also identify virus-like mesoporous nanoparticles as being of interest in the design of nanoparticles as delivery systems for antimicrobial peptides.
Background: Swallowing rehabilitation in curative treated patients with oral cancer is still a challenge. Different factors may influence these patients’ swallowing function. The aim of this study ...was to identify factors associated with swallowing function up to 5 years after cancer treatment. Methods: Swallowing duration and frequency of 5 mL water and 15 mL applesauce were measured in 123 patients treated for oral cancer. Mixed model analyses were performed to identify associated factors. Results: Age influenced all measured swallowing outcomes. Assessment moment, gender, tumor location, maximum tongue force, and tactile sensory function of the tongue were associated with both water and applesauce swallowing duration, tumor classification was associated with water swallowing duration, and alcohol consumption was associated with applesauce swallowing duration. Assessment moment, cancer treatment, maximum tongue force, and tactile sensory function of the tongue were associated with water and applesauce swallowing frequency. Conclusion: Patients who are older at diagnosis, women, and patients who regularly consume alcohol before their treatment may have poorer swallow functioning after curative oral cancer treatment. Patients that fit these criteria should have their swallowing evaluated during clinical follow-ups and sent to swallowing therapy when needed. During this therapy, optimizing tongue function needs attention to maintain an optimal swallowing function.
The bio-flocculants used in this study were synthesised by the Mannich reaction, which includes three reagents: a substrate (tannin extracts of Acacia, Quebracho, and Castanea), formaldehyde, and an ...amine derivative (ethanolamine, diethanolamine, ammonium chloride). Nine natural flocculants were prepared by combining extracts and amines; these products were evaluated in three different wastewater samples in two experimental phases. In phase I, five physicochemical parameters were analysed. From the data obtained, a multivariate, completely randomised design (CRD-Manava) was used, with a factorial arrangement and mean plots. In phase II, the three bio-flocculants with the most statistically significant responses and their mixtures were examined, evaluating 14 biological and physicochemical parameters. Statistical analysis was guided in this phase by CRD blocks, finding a significant removal in the physicochemical parameters analysed in the different types of wastewater and obtaining removal rates between 50 and 90%, depending on the parameter. At the end of both phases, the bio-flocculants acacia-ammonium chloride and quebracho-diethanolamine were the most efficient in the removal of turbidity (34-99%), true colour (93-100%) and total solids (12-99%). In addition, the natural flocculants showed low mutagenicity index (MI: 0.33-0.93) compared to aluminium sulphate (MI: 4.87-8.81).
Oral Pathology (OP) and Oral Medicine (OM) are specialties in dentistry whose main objective is the diagnosis and treatment of oral and maxillofacial diseases, and aspects related to the academic ...training of professionals and fields of practice are distinct and heterogeneous around the world. This study aimed to evaluate professional training and areas of activity in OP and OM in Latin American countries.
A questionnaire was sent to 11 countries, with a professional in each country responsible for answering it. The questionnaire had 21 questions related to the process of professional training, areas of practice, the existence of scientific events in each country, and also collected demographic and population information.
OP and OM are practiced in all the countries studied, but the specialty is not recognized in all of them. Brazil was the first to recognize both as a specialty. Postgraduate programs designed to train specialists are available in various countries. Two countries offer residency programs, 6 countries provide specialization courses, 6 offer master's programs, and 3 have doctoral programs. Brazil boasts the highest number of undergraduate courses (n=412), while Uruguay has the lowest (n=2). Professional societies representing the specialty exist in ten countries. Brazil has the highest number of OP and OM specialists (n=422 and 1,072), while Paraguay has the smallest number (n=1 and 3).
Although both specialties are widely practiced around the globe, professional training, the number of dentists trained and the fields of professional practice are very different between the countries studied.
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