1,177 research outputs found
Structure prediction and characterization of CuI-based ternary -type transparent conductors
Zincblende copper iodide has attracted significant interest as a potential
material for transparent electronics, thanks to its exceptional light
transmission capabilities in the visible range and remarkable hole
conductivity. However, remaining challenges hinder the utilization of copper
iodide's unique properties in real-world applications. To address this,
chalcogen doping has emerged as a viable approach to enhance the hole
concentration in copper iodide. In search of further strategies to improve and
tune the electronic properties of this transparent semiconductor, we
investigate the ternary phase diagram of copper and iodine with sulphur or
selenium by performing structure prediction calculations using the minima
hopping method. As a result, we find 11 structures located on or near the
convex hull, 9 of which are unreported. Based on our band structure
calculations, it appears that sulphur and selenium are promising candidates for
achieving ternary semiconductors suitable as -type transparent conducting
materials. Additionally, our study reveals the presence of unreported phases
that exhibit intriguing topological properties. These findings broaden the
scope of potential applications for these ternary systems, highlighting the
possibility of harnessing their unique electronic characteristics in diverse
electronic devices and systems
Directional Charge Separation in Isolated Organic Semiconductor Crystalline Nanowires
One of the fundamental design paradigms in organic photovoltaic device engineering is based on the idea that charge separation is an extrinsically driven process requiring an interface for exciton fission. This idea has driven an enormous materials science engineering effort focused on construction of domain sizes commensurate with a nominal exciton diffusion length of order 10 nm. Here, we show that polarized optical excitation of isolated pristine crystalline nanowires of a small molecule n-type organic semiconductor, 7,8,15,16-tetraazaterrylene, generates a significant population of charge-separated polaron pairs along the π-stacking direction. Charge separation was signalled by pronounced power-law photoluminescence decay polarized along the same axis. In the transverse direction, we observed exponential decay associated with excitons localized on individual monomers. We propose that this effect derives from an intrinsic directional charge-transfer interaction that can ultimately be programmed by molecular packing geometry
Implications of porpoise echolocation and dive behaviour on passive acoustic monitoring
Funding: The post-doctoral position for J.D.J.M. was funded by a FNU – Danish Natural Science Research Council grant to P.T.M. This study was also funded by the German Federal Agency for Nature Conservation via the grants “Effects of underwater noise on marine vertebrates” (Cluster 7, Z1.2-53302/2010/14) and “Under Water Noise Effects—UWE” (Project No. FKZ 3515822000). The contribution by T.A.M. was funded under the ACCURATE project (U.S. Navy Living Marine Resources Program, Contract No. N3943019C2176) and CEAUL (funded by FCT—Fundação para a Ciência e a Tecnologia, Portugal, through Project No. UIDB/00006/2020).Harbour porpoises are visually inconspicuous but highly soniferous echolocating marine predators that are regularly studied using passive acoustic monitoring (PAM). PAM can provide quality data on animal abundance, human impact, habitat use, and behaviour. The probability of detecting porpoise clicks within a given area ( P ̂ ) is a key metric when interpreting PAM data. Estimates of P ̂ can be used to determine the number of clicks per porpoise encounter that may have been missed on a PAM device, which, in turn, allows for the calculation of abundance and ideally non-biased comparison of acoustic data between habitats and time periods. However, P ̂ is influenced by several factors, including the behaviour of the vocalising animal. Here, the common implicit assumption that changes in animal behaviour have a negligible effect on P ̂ between different monitoring stations or across time is tested. Using a simulation-based approach informed by acoustic biologging data from 22 tagged harbour porpoises, it is demonstrated that porpoise behavioural states can have significant (up to 3× difference) effects on P ̂ . Consequently, the behavioural state of the animals must be considered in analysis of animal abundance to avoid substantial over- or underestimation of the true abundance, habitat use, or effects of human disturbance.Publisher PDFPeer reviewe
Programmable oligomers targeting 5'-GGGG-3' in the minor groove of DNA and NF-kappaB binding inhibition
A series of hairpin oligomers containing benzimidazole (Bi) and imidazopyridine (Ip) rings were synthesized and screened to target 5'-WGGGGW-3', a core sequence in the DNA-binding site of NF-kappaB, a prolific transcription factor important in biology and disease. Five Bi and Ip containing oligomers bound to the 5'-WGGGGW-3' site with high affinity. One of the oligomers (Im-Im-Im-Im-gamma-Py-Bi-Py-Bi-beta-Dp) was able to inhibit DNA binding by the transcription factor NF-kappaB
Atrial Natriuretic Peptide Induces Postprandial Lipid Oxidation in Humans
OBJECTIVE—Atrial natriuretic peptide (ANP) regulates arterial blood pressure. In addition, ANP has recently been shown to promote human adipose tissue lipolysis through cGMP-mediated hormone-sensitive lipase activation. We hypothesized that ANP increases postprandial free fatty acid (FFA) availability and energy expenditure while decreasing arterial blood pressure
Climate change impacts on seagrass meadows and macroalgal forests: an integrative perspective on acclimation and adaptation potential
Marine macrophytes are the foundation of algal forests and seagrass meadows-some of the most productive and diverse coastal marine ecosystems on the planet. These ecosystems provide nursery grounds and food for fish and invertebrates, coastline protection from erosion, carbon sequestration, and nutrient fixation. For marine macrophytes, temperature is generally the most important range limiting factor, and ocean warming is considered the most severe threat among global climate change factors. Ocean warming induced losses of dominant macrophytes along their equatorial range edges, as well as range extensions into polar regions, are predicted and already documented. While adaptive evolution based on genetic change is considered too slow to keep pace with the increasing rate of anthropogenic environmental changes, rapid adaptation may come about through a set of non-genetic mechanisms involving the functional composition of the associated microbiome, as well as epigenetic modification of the genome and its regulatory effect on gene expression and the activity of transposable elements. While research in terrestrial plants demonstrates that the integration of non-genetic mechanisms provide a more holistic picture of a species' evolutionary potential, research in marine systems is lagging behind. Here, we aim to review the potential of marine macrophytes to acclimatize and adapt to major climate change effects via intraspecific variation at the genetic, epigenetic, and microbiome levels. All three levels create phenotypic variation that may either enhance fitness within individuals (plasticity) or be subject to selection and ultimately, adaptation. We review three of the most important phenotypic variations in a climate change context, including physiological variation, variation in propagation success, and in herbivore resistance. Integrating different levels of plasticity, and adaptability into ecological models will allow to obtain a more holistic understanding of trait variation and a realistic assessment of the future performance and distribution of marine macrophytes. Such multi-disciplinary approach that integrates various levels of intraspecific variation, and their effect on phenotypic and physiological variation, is of crucial importance for the effective management and conservation of seagrasses and macroalgae under climate change.FCT
SFRH/BPD/115162/2016
Portuguese FCT through MARFOR
Biodiversa/0004/2015
Norwegian Research Council (Havkyst project)
243916
European Regional Development Fund (ERDF)
Mar 2020 program through the VALPRAD project
16-01-04-FMP-0007
SFRH/PBD/107878/2015info:eu-repo/semantics/publishedVersio
Brake response time before and after total knee arthroplasty: a prospective cohort study
<p>Abstract</p> <p>Background</p> <p>Although the numbers of total knee arthroplasty (TKA) are increasing, there is only a small number of studies investigating driving safety after TKA. The parameter 'Brake Response Time (BRT)' is one of the most important criteria for driving safety and was therefore chosen for investigation.</p> <p>The present study was conducted to test the hypotheses that patients with right- or left-sided TKA show a significant increase in BRT from pre-operative (pre-op, 1 day before surgery) to post-operative (post-op, 2 weeks post surgery), and a significant decrease in BRT from post-op to the follow-up investigation (FU, 8 weeks post surgery). Additionally, it was hypothesized that the BRT of patients after TKA is significantly higher than that of healthy controls.</p> <p>Methods</p> <p>31 of 70 consecutive patients (mean age 65.7 +/- 10.2 years) receiving TKA were tested for their BRT pre-op, post-op and at FU. BRT was assessed using a custom-made driving simulator. We used normative BRT data from 31 healthy controls for comparison.</p> <p>Results</p> <p>There were no significant increases between pre-op and post-op BRT values for patients who had undergone left- or right-sided TKA. Even the proportion of patients above a BRT threshold of 700 ms was not significantly increased postop. Controls had a BRT which was significantly better than the BRT of patients with right- or left-sided TKA at all three time points.</p> <p>Conclusion</p> <p>The present study showed a small and insignificant postoperative increase in the BRT of patients who had undergone right- or left-sided TKA. Therefore, we believe it is not justified to impair the patient's quality of social and occupational life post-surgery by imposing restrictions on driving motor vehicles beyond an interval of two weeks after surgery.</p
Adaptation of targeted nanocarriers to changing requirements in antimalarial drug delivery.
The adaptation of existing antimalarial nanocarriers to new Plasmodium stages, drugs, targeting molecules, or encapsulating structures is a strategy that can provide new nanotechnology-based, cost-efficient therapies against malaria. We have explored the modification of different liposome prototypes that had been developed in our group for the targeted delivery of antimalarial drugs to Plasmodium-infected red blood cells (pRBCs). These new models include: (i) immunoliposome-mediated release of new lipid-based antimalarials; (ii) liposomes targeted to pRBCs with covalently linked heparin to reduce anticoagulation risks; (iii) adaptation of heparin to pRBC targeting of chitosan nanoparticles; (iv) use of heparin for the targeting of Plasmodium stages in the mosquito vector; and (v) use of the non-anticoagulant glycosaminoglycan chondroitin 4-sulfate as a heparin surrogate for pRBC targeting. The results presented indicate that the tuning of existing nanovessels to new malaria-related targets is a valid low-cost alternative to the de novo development of targeted nanosystems
- …