2,455 research outputs found
Hepatocytes and IL-15: A Favorable Microenvironment for T Cell Survival and CD8+ T Cell Differentiation
Human intrahepatic lymphocytes are enriched in CD1d-unrestricted T cells coexpressing NKR. Although the origin of this population remains controversial, it is possible to speculate that the hepatic microenvironment, namely epithelial cells or the cytokine milieu, may play a role in its shaping. IL-15 is constitutively expressed in the liver and has a key role in activation and survival of innate and tissue-associated immune cells. In this in vitro study, we examined whether hepatocyte cell lines and/or IL-15 could play a role in the generation of NK-like T cells. The results show that both HepG2 cells and a human immortalized hepatocyte cell line increase survival and drive basal proliferation of T cells. In addition, IL-15 was capable of inducing Ag-independent up-regulation of NKR, including NKG2A, Ig-like receptors, and de novo expression of CD56 and NKp46 in CD8(+)CD56(-) T cells. In conclusion, our study suggests that hepatocytes and IL-15 create a favorable microenvironment for T cells to growth and survive. It can be proposed that the increased percentage of intrahepatic nonclassical NKT cells could be in part due to a local CD8(+) T cell differentiation.This work was supported by grants from the American Portuguese Biomedical Research Fund (Inova Grant) and from ISCSN-CESPU (Grants CESPU 1F/05/2005 and CESPU 2F/03/2006). M.P.C. was supported by a fellowship from Fundação para a Ciência e a Tecnologia (SFRH/BD/24396/2005)
Optimization and characterization of biosurfactant production by Bacillus subtilis isolates towards Microbial Enhanced Oil Recovery applications
Biosurfactant production by three Bacillus subtilis strains (#309, #311 and #573) isolated
from Brazilian crude oils was optimized based on different carbon and nitrogen sources. The lowest
surface tension values were obtained using sucrose containing media for the three isolates.
Biosurfactants produced by each strain were characterized by Fourier transform infrared spectroscopy
(FTIR), proton nuclear magnetic resonance (1HNMR), and Matrix-assisted laser desorption ionizationtime
of flight mass spectrometry (MALDI-TOF). The chemical characterization showed that the three
isolates produced very similar mixtures, containing C13-, C14- and C15-surfactin, although in different
proportions. The structure of surfactins produced by the three strains was shown to be in good
agreement with their surface-activities. The interfacial-activities of the biosurfactants were
characterized and compared with chemical surfactants. Furthermore, the application of biosurfactants
and chemical surfactants in oil recovery was evaluated. The results obtained showed that
biosurfactants have better interfacial-activity and oil recovery efficiency than common chemical
surfactants, thus being more attractive to be applied in Microbial Enhanced Oil Recovery.This work was supported by PARTEX OIL AND GAS. Jorge F.B. Pereira acknowledges the financial support from Fundacao para a Ciencia e a Tecnologia through doctoral research grant SFRH/BD/60228/2009. Rui Vitorino acknowledges the financial support from QOPNA and RNEM by the Fundacao para a Ciencia e a Tecnologia
LITHIUM-DOPED SILK FIBROIN FILMS FOR APPLICATION IN ELECTROCHROMIC DEVICES
Abstract Silk fibroin (SF) is a commonly available natural biopolymer produced in specialized glands of arthropods, with a long history of use in textile production and also in health cares. The exceptional intrinsic properties of these fibers, such as self-assembly, machinability, biocompatibility, biodegradation or non-toxicity, offer a wide range of exciting opportunitie
Nanofluid Based on Glucose‐Derived Carbon Dots Functionalized with [Bmim]Cl for the Next Generation of Smart Windows
The design of new advanced materials and technologies is essential for the development of smart windows for the next generation of energy‐efficient buildings. Here, it is demonstrated that the functionalization of glucose‐derived carbon dots with 1‐butyl‐3‐methylimidazolium chloride results in a self‐standing, water‐soluble, viscous, reusable nanofluid with self‐improving conductivity, thermotropy around 30–40 °C, and ultraviolet blocking ability. Its synthesis is straightforward, clean, fast, and cheap. At 36 °C (hot summer day), a sun‐actuated thermotropic (TT) device incorporating a 95% w/w nanofluid aqueous solution exhibits a transmittance variation (ΔT ) of 9% at 550/1000 nm, which is amplified to 47/31% via the surface plasmon resonance effect. An integrated self‐healing system enabling independent sun‐actuated TT and voltage‐actuated electrochromic (EC) operation is also produced. The low‐energy EC device offers bright hot and dark cold modes (ΔT = 68/64%), excellent cycling stability, unprecedented coloration efficiency values (−1.73 × 106/−1.67 × 106 cm2 C−1 (coloring) and +1.12 × 107/+1.08 × 107 cm2 C−1 (bleaching) at ±2.5 V), and impressive memory effect. The disruptive design and sustainable synthesis of the new nanofluid proposed here will foster the agile development of novel products with improved ecological footprint.This research was funded by the National Funds by Foundation for Science and Technology (FCT) and by the FEDER funds through POCI-COMPETE 2020-Operational Programme Competitiveness and Internationalization in Axis I: Strengthening research, technological development and innovation (UID/QUI/00616/2013, UID/QUI/50006/2019, UID/Multi/00709/2013, UID/QUI/00313/2019, UID/CTM/50025, POCI-01-0145-FEDER-007491, POCI-01-0145-FEDER-007688, UID/CTM/50025, POCI-01-0145-FEDER-016884, PTDC/CTM-NAN/0956/2014, SAICT/PAC/0032/2015, POCI-01-0145-FEDER-016422, and NORTE-01-0145-FEDER-030858). R.F.P.P. acknowledges FCT-MCTES for SFRH/BPD/87759/2012 grant. R. Rego and M. Fernandes (UTAD, Vila Real) and E. Pereira (FCUP, Porto) are acknowledged for their assistance.info:eu-repo/semantics/publishedVersio
Enhanced enzyme reuse through the bioconjugation of L-asparaginase and silica-based supported ionic liquid-like phase materials
L-asparaginase (ASNase) is an amidohydrolase that can be used as a biopharmaceutical, as an agent for acrylamide reduction, and as an active molecule for L-asparagine detection. However, its free form displays some limitations, such as the enzyme’s single use and low stability. Hence, immobilization is one of the most effective tools for enzyme recovery and reuse. Silica is a promising material due to its low-cost, biological compatibility, and tunable physicochemical characteristics if properly functionalized. Ionic liquids (ILs) are designer compounds that allow the tailoring of their physicochemical properties for a given task. If properly designed, bioconjugates combine the features of the selected ILs with those of the support used, enabling the simple recovery and reuse of the enzyme. In this work, silica-based supported ionic liquid-like phase (SSILLP) materials with quaternary ammoniums and chloride as the counterion were studied as novel supports for ASNase immobilization since it has been reported that ammonium ILs have beneficial effects on enzyme stability. SSILLP materials were characterized by elemental analysis and zeta potential. The immobilization process was studied and the pH effect, enzyme/support ratio, and contact time were optimized regarding the ASNase enzymatic activity. ASNase–SSILLP bioconjugates were characterized by ATR-FTIR. The bioconjugates displayed promising potential since [Si][N3444]Cl, [Si][N3666]Cl, and [Si][N3888]Cl recovered more than 92% of the initial ASNase activity under the optimized immobilization conditions (pH 8, 6 × 10−3 mg of ASNase per mg of SSILLP material, and 60 min). The ASNase–SSILLP bioconjugates showed more enhanced enzyme reuse than reported for other materials and immobilization methods, allowing five cycles of reaction while keeping more than 75% of the initial immobilized ASNase activity. According to molecular docking studies, the main interactions established between ASNase and SSILLP materials correspond to hydrophobic interactions. Overall, it is here demonstrated that SSILLP materials are efficient supports for ASNase, paving the way for their use in the pharmaceutical and food industries.publishe
Solar spectral management with electrochromic devices including PMMA films doped with biluminescent ionosilicas
The technological potential of poly(methyl methacrylate) (PMMA)-based composite films doped with lanthanide-doped sol–gel derived ionosilicas (IS-Ln) previously proposed for luminescent down-shifting (LDS) and luminescent solar concentrator (LSC) layers connected to photovoltaic (PV) cells is extended here to electrochromic devices (ECDs), targeting the fabrication of single energy harvesting/conversion/management LSC-LDS/PV/ECD systems. These integrated devices have foreseen application in the windows of future zero-energy buildings of smart cities. The proof-of-concept is given with the report of the electro-optical performance of an ECD comprising an optimized electrolyte film composed of PMMA, IS-Nd, and IS-Eu, and the 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid. This amorphous electrolyte is stable below 160 °C, exhibits high ionic conductivity (2.13 × 10−4 and 8.76 × 10−4 S cm−1 at room temperature and 44 °C, respectively), and emits in the visible (red color) and near-infrared (NIR) spectral regions. The device demonstrated fast switching speed (50 s) and high transparency in the visible-to-NIR spectral regions (transmittance (T) = 79/96/89/77% at 555/1000/1500/1650 nm in the as-prepared state, respectively). Upon application of ±2.5 V for 200 cycles, at the same wavelengths, the Tbleached/Tcolored values were 44/28, 46/26, 39/20, and 27/9%, respectively, and the coloration efficiency (CE) values CEin/CEout values were −302/+181, −381/+228, −446/+267 and −734/+440 cm2 C−1, respectively.publishe
Development of pH-Sensitive magnetoliposomes containing shape anisotropic nanoparticles for potential application in combined cancer therapy
Late diagnosis and systemic toxicity associated with conventional treatments make oncological therapy significantly difficult. In this context, nanomedicine emerges as a new approach in the prevention, diagnosis and treatment of cancer. In this work, pH-sensitive solid magnetoliposomes (SMLs) were developed for controlled release of the chemotherapeutic drug doxorubicin (DOX). Shape anisotropic magnetic nanoparticles of magnesium ferrite with partial substitution by calcium (Mg0.75Ca0.25Fe2O4) were synthesized, with and without calcination, and their structural, morphological and magnetic properties were investigated. Their superparamagnetic properties were evaluated and heating capabilities proven, either by exposure to an alternating magnetic field (AMF) (magnetic hyperthermia) or by irradiation with near-infrared (NIR) light (photothermia). The Mg0.75Ca0.25Fe2O4 calcined nanoparticles were selected to integrate the SMLs, surrounded by a lipid bilayer of DOPE:Ch:CHEMS (45:45:10). DOX was encapsulated in the nanosystems with an efficiency above 98%. DOX release assays showed a much more efficient release of the drug at pH = 5 compared to the release kinetics at physiological pH. By subjecting tumor cells to DOX-loaded SMLs, cell viability was significantly reduced, confirming that they can release the encapsulated drug. These results point to the development of efficient pH-sensitive nanocarriers, suitable for a synergistic action in cancer therapy with magnetic targeting, stimulus-controlled drug delivery and dual hyperthermia (magnetic and plasmonic) therapy.This work was funded by the Portuguese Foundation for Science and Technology (FCT) within the framework of the Strategic Funding of Research Units UIDB/04650/2020 (CF-UM-UP), UIDB/00319/2020 (ALGORITMI), UIDB/04077/2020 (MEtRICs), UIDB/04436/2020 (CMEMS) and UIDB/00511/2020 (LEPABE). FCT, POCI, FEDER and NORTE2020 are acknowledged for funding through research projects PTDC/QUI-QFI/28020/2017, EXPL/EMD-EMD/0650/2021, PTDC/EEI-EEE/2846/2021 and NORTE-01-0145-FEDER-000054. MINECO (Spain) is acknowledged for project MAT2016-76824-C3-2-R. B.D.C. and V.M.C. acknowledge FCT for PhD grants SFRH/BD/141936/2018 (B.D.C.) and UI/BD/151028/2021 (V.M.C.). R.O.R. thanks FCT for contract 2020.03975.CEECIND
The RICH detector of the AMS-02 experiment: status and physics prospects
The Alpha Magnetic Spectrometer (AMS), whose final version AMS-02 is to be
installed on the International Space Station (ISS) for at least 3 years, is a
detector designed to measure charged cosmic ray spectra with energies up to the
TeV region and with high energy photon detection capability up to a few hundred
GeV. It is equipped with several subsystems, one of which is a proximity
focusing RICH detector with a dual radiator (aerogel+NaF) that provides
reliable measurements for particle velocity and charge. The assembly and
testing of the AMS RICH is currently being finished and the full AMS detector
is expected to be ready by the end of 2008. The RICH detector of AMS-02 is
presented. Physics prospects are briefly discussed.Comment: 5 pages. Contribution to the 10th ICATPP Conference on Astroparticle,
Particle, Space Physics, Detectors and Medical Physics Applications (Como
2007). Presenter: Rui Pereir
Design of whey protein nanostructures for incorporation and release of nutraceutical compounds in food
Whey proteins are widely used as nutritional and functional ingredients in formulated foods because they are relative inexpensive, generally recognized as safe (GRAS) ingredient and possess important biological, physical and chemical functionalities. Denaturation and aggregation behavior of these proteins is of particular relevance toward manufacture of novel nanostructures with a number of potential uses. When these processes are properly engineered and controlled, whey proteins may be formed into nanohydrogels, nanofibrils or nanotubes and be used as carrier of bioactive compounds. This review intends to discuss the latest understandings of nanoscale phenomena of whey protein denaturation and aggregation that may contribute for the design of protein nanostructures. Whey protein aggregation and gelation pathways under different processing and environmental conditions such as microwave heating, high voltage and moderate electrical fields, high pressure, temperature, pH and ionic strength were critically assessed. Moreover, several potential applications of nanohydrogels, nanofibrils and nanotubes for controlled release of nutraceutical compounds (e.g. probiotics, vitamins, antioxidants and peptides) were also included. Controlling the size of protein networks at nanoscale through application of different processing and environmental conditions can open perspectives for development of nanostructures with new or improved functionalities for incorporation and release of nutraceuticals in food matrices.Oscar L. Ramos, Ricardo N. Pereira and Clara Fuci~nos gratefully acknowledge their Post-Doctoral grants (SFRH/BPD/80766/2011, SFRH/BPD/ 81887/2011, and SFRH/BPD/87910/2012, respectively) to the Fundação para a Ciência e Tecnologia (FCT, Portugal). All authors thank the FCT Strategic Project PEst-OE/EQB/LA0023/2013 and the Project “BioEnv— Biotechnology and Bioengineering for a sustainable world”, REF. NORTE07-0124-FEDER-000048, co-funded by Programa Operacional Regional do Norte (ON.2–O Novo Norte), QREN, FEDER
Coronary computed tomography angiography-adapted Leaman score as a tool to noninvasively quantify total coronary atherosclerotic burden
To describe a coronary computed tomography angiography (CCTA)-adapted Leaman score (CT-LeSc) as a tool to quantify total coronary atherosclerotic burden with information regarding localization, type of plaque and degree of stenosis and to identify clinical predictors of a high coronary atherosclerotic burden as assessed by the CT-LeSc. Single center prospective registry including a total of 772 consecutive patients undergoing CCTA (Dual-source CT) from April 2011 to March 2012. For the purpose of this study, 581 stable patients referred for suspected coronary artery disease (CAD) without previous myocardial infarction or revascularization procedures were included. Pre-test CAD probability was determined using both the Diamond-Forrester extended CAD consortium method (DF-CAD consortium model) and the Morise score. Cardiovascular risk was assessed with the HeartScore. The cut-off for the 3rd tercile (CT-LeSc ≥8.3) was used to define a population with a high coronary atherosclerotic burden. The median CT-LeSc in this population (n = 581, 8,136 coronary segments evaluated; mean age 57.6 ± 11.1; 55.8 % males; 14.6 % with diabetes) was 2.2 (IQR 0-6.8). In patients with CAD (n = 341), the median CT-LeSc was 5.8 (IQR 3.2-9.6). Among patients with nonobstructive CAD, most were classified in the lowest terciles (T1, 43.0 %; T2, 36.1 %), but 20.9 % were in the highest tercile (T3). The majority of the patients with obstructive CAD were classified in T3 (78.2 %), but 21.8 % had a CT-LeSc in lower terciles (T1 or T2). The independent predictors of a high CT-LeSc were: Male sex (OR 1.73; 95 % CI 1.04-2.90) diabetes (OR 2.91; 95 % CI 1.61-5.23), hypertension (OR 2.54; 95 % CI 1.40-4.63), Morise score ≥16 (OR 1.97; 95 % CI 1.06-3.67) and HeartScore ≥5 (OR 2.42; 95 % CI 1.41-4.14). We described a cardiac CT adapted Leaman score as a tool to quantify total (obstructive and nonobstructive) coronary atherosclerotic burden, reflecting the comprehensive information about localization, degree of stenosis and type of plaque provided by CCTA. Male sex, hypertension, diabetes, a HeartScore ≥5 % and a Morise score ≥16 were associated with a high coronary atherosclerotic burden, as assessed by the CT-LeSc. About one fifth of the patients with nonobstructive CAD had a CT-LeSc in the highest tercile, and this could potentially lead to a reclass
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