Design of double-walled carbon nanotubes for biomedical applications

Double-walled carbon nanotubes (DWNTs) prepared by catalytic chemical vapour deposition were functionalized in such a way that they were optimally designed as a nano-vector for the delivery of small interfering RNA (siRNA), which is of great interest for biomedical research and drug development. DWNTs were initially oxidized and coated with a polypeptide (Poly(Lys:Phe)), which was then conjugated to thiol-modified siRNA using a heterobifunctional cross-linker. The obtained oxDWNT–siRNA was characterized by Raman spectroscopy inside and outside a biological environment (mammalian cells). Uptake of the custom designed nanotubes was not associated with detectable biochemical perturbations in cultured cells, but transfection of cells with DWNTs loaded with siRNA targeting the green fluorescent protein (GFP) gene, serving as a model system, as well as with therapeutic siRNA targeting the survivin gene, led to a significant gene silencing effect, and in the latter case a resulting apoptotic effect in cancer cells

Revealing the foraging movements and diet of the White-faced Storm Petrel Pelagodroma marina in the NE Atlantic

The White-faced Storm Petrel (WFSP) Pelagodroma marina has a widespread distribution, although virtually nothing is known about their feeding ecology and distributions at-sea. To describe their foraging areas, a total of 77 birds were equipped with 1 g-GPS loggers on Selvagem Grande, Madeira, Portugal (30° 09′ N, 15° 52′ W), during the 2018 and 2019 breeding seasons. We also assessed the diet of WFSP by analysing 17 faecal samples from chicks and 1 regurgitation from an adult using DNA metabarcoding techniques. Additionally, we collected body feathers from ten WFSP chicks to determine mercury concentration. WFSP fed mainly in deep oceanic waters, travelling up to 400 km from the colony, and did not concentrate in any well-defned, population-level foraging hotspots. Some individuals foraged along the edge of the shelf, near the African coast and the Canary Islands, especially during chick rearing. The duration of foraging trips and the total distance travelled, were, on average, 5.1 days and 723 km during the incubation period and 3.0 days and 578 km during chick rearing. The diet of WFSP was dominated by fsh and cephalopods (crustacean prey were not detected), with Myctophidae (FO=71%) representing the main fsh family. WFSP often consume mesopelagic fsh, in line with their preference for deep oceanic waters and with a small diference in at sea behavior (i.e., travel speed) between the diurnal and nocturnal period. The relatively high concentrations of mercury accumulated in body feathers of WFSP chicks (3.45±1.44 mg kg−1 dry weight; range 1.68–6.01 mg kg−1) support the idea that WFSP raise their chicks mostly on mesopelagic prey from deep pelagic areas.CESAM; Fundação para a Ciência e Tecnologia - FCTinfo:eu-repo/semantics/publishedVersio

High-dimensional decoy-state quantum key distribution over 0.3 km of multicore telecommunication optical fibers

Multiplexing is a strategy to augment the transmission capacity of a communication system. It consists of combining multiple signals over the same data channel and it has been very successful in classical communications. However, the use of enhanced channels has only reached limited practicality in quantum communications (QC) as it requires the complex manipulation of quantum systems of higher dimensions. Considerable effort is being made towards QC using high-dimensional quantum systems encoded into the transverse momentum of single photons but, so far, no approach has been proven to be fully compatible with the existing telecommunication infrastructure. Here, we overcome such a technological challenge and demonstrate a stable and secure high-dimensional decoy-state quantum key distribution session over a 0.3 km long multicore optical fiber. The high-dimensional quantum states are defined in terms of the multiple core modes available for the photon transmission over the fiber, and the decoy-state analysis demonstrates that our technique enables a positive secret key generation rate up to 25 km of fiber propagation. Finally, we show how our results build up towards a high-dimensional quantum network composed of free-space and fiber based linksComment: Please see the complementary work arXiv:1610.01812 (2016

Introdução: justiça, direito(s) e instituições

Problematiza-se aqui o âmbito e a natureza do presente papel das instituições no governo das condutas numa variedade ampla de campos, do social ao jurídicoinfo:eu-repo/semantics/publishedVersio

ANÁLISE DE RISCO DE CONTAMINAÇÃO DAS ÁGUAS SUBTERRÂNEAS E SUPERFICIAIS DA REGIÃO DE PETROLINA (PE) E JUAZEIRO (BA)

Analisou-se o potencial de contaminação das águas subterrâneas e superficiais do Submédio do Rio São Francisco por pesticidas aplicados nas culturas de manga e uva, mediante critérios da Environmental Protection Agency, do índice de GUS e critérios propostos por GOSS. Todos os critérios utilizados levam em consideração as propriedades dos produtos aplicados, não demandando custos elevados nem muito tempo para o levantamento das informações e para a avaliação do potencial de contaminação. Os resultados obtidos reforçam a importância de disponibilizar informações sobre as propriedades físico-químicas dos pesticidas, principalmente o coeficiente de adsorção, cujo valor permite a previsão da mobilidade do composto no solo. Este fator, integrado ao conhecimento do tempo de degradação do produto até a metade de sua concentração inicial (meia-vida) no solo, fornece informações sobre a sua influência no potencial de contaminação das águas. Os resultados deste trabalho propiciam o conhecimento dos pesticidas com maior potencial de contaminação dos recursos hídricos, os quais devem ser priorizados no monitoramento ambiental in loco. GROUND AND SURFACE WATER OF THE REGIONS PETROLINA (PE) AND JUAZEIRO (BA) Abstract The contamination potential of ground water and surface water in the sub-middle portion of San Francisco river basin was analyzed for pesticides applied in mango and grape cultivation by following the criteria of Environmental Protection Agency and to the index of GUS and criteria proposed by GOSS. All the criteria used take into consideration the applied products properties, by not demanding high costs nor a long time for rising information and evaluating contamination potential. The results obtained reinforce the importance of information publication on the physicochemical properties of pesticides, especially data on adsorption coefficient, whose values allow to predict the pesticide mobility in soils. This factor combined with the pesticide degradation time to the half of its initial concentration (half life) in the soil, provides information on pesticide water contamination potential. The results of this work allow the identification of the pesticides with higher contamination potential to water resources, which should be prioritized in environmental monitoring in loco

Solid and aqueous magnetic liposomes as nanocarriers for a new potential drug active against breast cancer

In this work, iron oxide nanoparticles (NPs), with diameters around 12 nm, were synthesized by coprecipitation method. Both aqueous and solid magnetic liposomes containing magnetite NPs were obtained, with sizes below 140 nm. A new antitumor compound, a diarylurea derivative of thienopyridine, active against breast cancer, was incorporated in both aqueous and solid magnetoliposomes, being located mainly in the lipid membrane. A promising application of these magnetic liposomes in oncology is anticipated, allowing a combined therapeutic approach, using both chemotherapy and magnetic hyperthermia.Financial support by FCT-Portugal is acknowledged (Strategic Funding UID/FIS/04650/2013 and PhD grant SFRH/BD/90949/2012).info:eu-repo/semantics/publishedVersio

Radiative Corrections to the Aharonov-Bohm Scattering

We consider the scattering of relativistic electrons from a thin magnetic flux tube and perturbatively calculate the order $\alpha$, radiative correction, to the first order Born approximation. We show also that the second order Born amplitude vanishes, and obtain a finite inclusive cross section for the one-body scattering which incorporates soft photon bremsstrahlung effects. Moreover, we determine the radiatively corrected Aharonov-Bohm potential and, in particular, verify that an induced magnetic field is generated outside of the flux tube.Comment: 14 pages, revtex, 3 figure

Cellular localization, accumulation and trafficking of double-walled carbon nanotubes in human prostate cancer cells

Carbon nanotubes (CNTs) are at present being considered as potential nanovectors with the ability to deliver therapeutic cargoes into living cells. Previous studies established the ability of CNTs to enter cells and their therapeutic utility, but an appreciation of global intracellular trafficking associated with their cellular distribution has yet to be described. Despite the many aspects of the uptake mechanism of CNTs being studied, only a few studies have investigated internalization and fate of CNTs inside cells in detail. In the present study, intracellular localization and trafficking of RNA-wrapped, oxidized double-walled CNTs (oxDWNT–RNA) is presented. Fixed cells, previously exposed to oxDWNT–RNA, were subjected to immunocytochemical analysis using antibodies specific to proteins implicated in endocytosis; moreover cell compartment markers and pharmacological inhibitory conditions were also employed in this study. Our results revealed that an endocytic pathway is involved in the internalization of oxDWNT–RNA. The nanotubes were found in clathrin-coated vesicles, after which they appear to be sorted in early endosomes, followed by vesicular maturation, become located in lysosomes. Furthermore, we observed co-localization of oxDWNT–RNA with the small GTP-binding protein (Rab 11), involved in their recycling back to the plasma membrane via endosomes from the trans-golgi network