Building material manufacturers must support new production models that encourage the manufacture of more efficient and sustainable products. This includes thinking about savings in the use of raw ...materials, a contribution to the energy efficiency of buildings during their useful life, and a reduction in the generation and deposit of waste in landfills. In this research, an analysis of the thermal properties of gypsum composites added with plastic waste is carried out using the most common methods, the steady state method and the transient plane source method, and the effect of water saturation on these composites is tested. The results show an improvement in the thermal performance of the composites (values reduced with respect to the reference by 4-7%), despite their heterogeneity, as well as a variation in the measurements carried out, depending on the method used for the measurements (variation up to 10%). It is also found that the degree of humidity negatively affects the thermal conductivity coefficient but, on the contrary, this coefficient is not altered in the composites with plastic waste, due to their lower hygroscopicity. Therefore, it is considered that the proposed eco-plasters are a good alternative to traditional plasters, with which to contribute to the achievement of the objectives of the current European directives on waste and circular economy.
Many types of fish passage facilities have been built worldwide to mitigate river fragmentation by instream barriers and partially restore upstream movements of fish. Among these, fish lifts are a ...design that enables fish to pass through high‐head obstacles (>15 m height) and can be considered the most cost‐effective fishway. However, fishways may also be used by non‐native invasive species to disperse and impact new areas and organisms upstream. As far as the authors are aware, this short communication is the first record of the red swamp crayfish (Procambarus clarkii) passing through a fish lift. The lift, built at the Touvedo hydropower plant on the Lima River (northwestern Portugal), was mainly designed for the upstream passage of diadromous fish. Fish‐lift use and upstream passage of two crayfish occurred over 3 years (November 2017–October 2020) during periods of turbine shutdown and high water temperatures (18°C). In the present case, the crayfish passage should not pose a serious threat due to the limiting characteristics of the upstream lotic environment. Nevertheless, despite the small sample size, this study shows the importance of considering the passage of invasive crayfish species while planning future fishways and the need to continuously monitor such facilities to detect the passage of this and other non‐native invasive species.
Tachyplesin I, II and III are host defense peptides from horseshoe crab species with antimicrobial and anticancer activities. They have an amphipathic β-hairpin structure, are highly ...positively-charged and differ by only one or two amino acid residues. In this study, we compared the structure and activity of the three tachyplesin peptides alongside their backbone cyclized analogues. We assessed the peptide structures using nuclear magnetic resonance (NMR) spectroscopy, then compared the activity against bacteria (both in the planktonic and biofilm forms) and a panel of cancerous cells. The importance of peptide-lipid interactions was examined using surface plasmon resonance and fluorescence spectroscopy methodologies. Our studies showed that tachyplesin peptides and their cyclic analogues were most potent against Gram-negative bacteria and melanoma cell lines, and showed a preference for binding to negatively-charged lipid membranes. Backbone cyclization did not improve potency, but improved peptide stability in human serum and reduced toxicity toward human red blood cells. Peptide-lipid binding affinity, orientation within the membrane, and ability to disrupt lipid bilayers differed between the cyclized peptide and the parent counterpart. We show that tachyplesin peptides and cyclized analogues have similarly potent antimicrobial and anticancer properties, but that backbone cyclization improves their stability and therapeutic potential.
Objectives
To evaluate bleaching efficacy and oral health-related quality of life (ORHQoL) of three bleaching systems with similar hydrogen peroxide (HP) concentration for up to 6 months ...post-treatment.
Materials and methods
A randomized controlled trial was designed with three parallel groups: group A — in-office 6% HP paint-on varnish; group B — at-home 6% HP with adaptable tray; group C — at-home 16% carbamide peroxide with custom tray. At three different stages (baseline, after bleaching, and 6-month follow-up), ORHQoL was evaluated by the OHIP-14 questionnaire and tooth color of the upper canines and central incisors were measured by two shade guides and a spectrophotometer (measuring CIE L*a*b* with respective color/whiteness differences − Δ
E
00
/ΔWI
D
). Results were presented as mean and 95% confidence intervals and statistical tests were performed appropriately, considering a significance level of
α
= 0.05.
Results
All groups presented significant color differences (
P
< 0.05) between all stages, with Δ
E
00
/ΔWI
D
surpassing the perceptibility threshold in 98% cases, with group C’s results being significantly (
P
< 0.05) higher when compared to other groups, although with significantly (
P
< 0.05) higher values of color relapse. Significative ORHQoL improvements (
P
< 0.05) were detected after bleaching in a global analysis with no differences between techniques.
Conclusions
All techniques presented bleaching efficacy, color stability, and improvements in ORHQoL up to 6 months post-treatment.
Clinical significance
Clinicians may consider both at-home and in-office bleaching techniques with 6% HP to attain long-lasting satisfactory clinical results while producing positive changes in ORHQoL.
Whitening products commonly utilize hydrogen peroxide (HP) as an active principle, which can penetrate dental tissues with potential side effects due to its low molecular weight. This study aimed to ...evaluate the HP diffusion of two in-office whitening products, namely 6% VivaStyle Paint On Plus (VS) and Opalescence Boost 40% (OP), in different tooth types. Additionally, the influence of the area of exposure, dental tissue thickness and pulp chamber volume was assessed. Each group consisted of eighteen intact anterior (A), premolar (PM) and molar (M) human teeth, and a positive pulpal pressure model was employed. The samples were analyzed using spectrophotometry, and results were expressed as the mean and 95% confidence interval. Statistical tests and linear regression models were appropriately applied at α = 5%. The total HP (µg) retrieved was as follows: VS-A, 1.333 1.214, 1.452; OP-A, 1.538 1.457, 1.620; VS-PM, 1.208 1.123, 1.291; OP-PM, 3.628 3.401, 3.855; VS-M, 2.560 2.297, 2.823; and OP-M, 4.197 3.997, 4.396, with statistically significant differences in diffusion kinetics between whitening products for PM and M. Several HP concentrations attained a minimum cytotoxicity value of 2.22 µg/mL. The regression model shows that OP exposed the pulp chamber to 1.421 µg of HP more than that of VS. Different whitening products can cause cytotoxic HP concentrations in the pulp chamber, with a higher risk observed in molars.
The need for more effective and safer pharmaceuticals is a persistent quest. Microbial adaptations create the need to permanently develop new antimicrobials (AMPs), for instance. Similarly, ...intracellular delivery of drugs is still a challenge and translocation of membranes for drug delivery is an area of intense research. Peptides can be used both as AMP drug leads and drug carrier systems for intracellular delivery. Multifunctional proteins are abundant in viruses but, surprisingly, have never been thoroughly screened for bioactive peptide sequences.
Using the AMPA and CellPPD online tools, we have evaluated the propensity of viral proteins to comprise AMP or cell-penetrating peptides (CPPs). Capsid proteins from both enveloped and non-enveloped viruses, and membrane and envelope proteins from enveloped viruses, in a total of 272 proteins from 133 viruses, were screened to detect the presence of potential AMP and CPP sequences. A pool of 2444 and 426 CPP and AMP sequences, respectively, were discovered. The capsids of flaviviruses are the best sources of these peptides reaching more than 80% of CPP sequence coverage per protein. Selected sequences were tested experimentally and validated the results. Overall, this study reveals that viruses form a natural multivalent biotechnological platform still underexplored in drug discovery and the heterogeneous abundance of CPP/AMP sequences among viral families opens new avenues in viral biology research.
Weak Memories de Sousa Dias, Susana
Film quarterly,
07/2020, Volume:
73, Issue:
4
Journal Article
Peer reviewed
The Portuguese documentary filmmaker Susana de Sousa Dias offers a comprehensive overview of her career over the past fifteen years, beginning with Natureza Morta (Still Life, 2005) through her ...current project, Estação Total (Total Station, working title). She explains that her films aim to reflect on authoritarian systems—especially the forty-eight year rule of Portuguese dictator António de Oliveira Salazar—and to shed light on the present through the materials of the past. In terms of her cinematic praxis, she discusses the vital importance of two techniques: “montage within the shot”—that is, a montage with visual, spatial, and temporal depth—and “decelerated movement,” which describes her approach to time and duration. Her most recent film, Fordlandia Malaise (2019), extends her work on repressive regimes to encompass current geopoliticals tructures with their underlying colonialist and imperialist heritage, whether derived from a European origin or from the ruth less capitalism of the New World.
Abstract
Background
Infections caused by bacterial biofilms are very difficult to treat. The use of currently approved antibiotics even at high dosages often fails, making the treatment of these ...infections very challenging. Novel antimicrobial agents that use distinct mechanisms of action are urgently needed.
Objectives
To explore the use of G1K,K8RcGm, a designed cyclic analogue of the antimicrobial peptide gomesin, as an alternative approach to treat biofilm infections.
Methods
We studied the activity of G1K,K8RcGm against biofilms of Staphylococcus aureus, a pathogen associated with several biofilm-related infections. A combination of atomic force and real-time confocal laser scanning microscopies was used to study the mechanism of action of the peptide.
Results
The peptide demonstrated potent activity against 24 h-preformed biofilms through a concentration-dependent ability to kill biofilm-embedded cells. Mechanistic studies showed that G1K,K8RcGm causes morphological changes on bacterial cells and permeabilizes their membranes across the biofilm with a half-time of 65 min. We also tested an analogue of G1K,K8RcGm without disulphide bonds, and a linear unfolded analogue, and found both to be inactive.
Conclusions
The results suggest that the 3D structure of G1K,K8RcGm and its stabilization by disulphide bonds are essential for its antibacterial and antibiofilm activities. Moreover, our findings support the potential application of this stable cyclic antimicrobial peptide to fight bacterial biofilms.
Abstract
Objectives
To investigate the mechanism of action at the molecular level of pepR, a multifunctional peptide derived from the Dengue virus capsid protein, against Staphylococcus aureus ...biofilms.
Methods
Biofilm mass, metabolic activity and viability were quantified using conventional microbiology techniques, while fluorescence imaging methods, including a real-time calcein release assay, were employed to investigate the kinetics of pepR activity at different biofilm depths.
Results
Using flow cytometry-based assays, we showed that pepR is able to prevent staphylococcal biofilm formation due to a fast killing of planktonic bacteria, which in turn resulted from a peptide-induced increase in the permeability of the bacterial membranes. The activity of pepR against pre-formed biofilms was evaluated through the application of a quantitative live/dead confocal laser scanning microscopy (CLSM) assay. The results show that the bactericidal activity of pepR on pre-formed biofilms is dose and depth dependent. A CLSM-based assay of calcein release from biofilm-embedded bacteria was further developed to indirectly assess the diffusion and membrane permeabilization properties of pepR throughout the biofilm. A slower diffusion and delayed activity of the peptide at deeper layers of the biofilm were quantified.
Conclusions
Overall, our results show that the activity of pepR on pre-formed biofilms is controlled by its diffusion along the biofilm layers, an effect that can be counteracted by an additional administration of peptide. Our study sheds new light on the antibiofilm mechanism of action of antimicrobial peptides, particularly the importance of their diffusion properties through the biofilm matrix on their activity.
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