2,649 research outputs found
Effective action in DSR1 quantum field theory
We present the one-loop effective action of a quantum scalar field with DSR1
space-time symmetry as a sum over field modes. The effective action has real
and imaginary parts and manifest charge conjugation asymmetry, which provides
an alternative theoretical setting to the study of the particle-antiparticle
asymmetry in nature.Comment: 8 page
Study of the Organic Extraction and Acidic Leaching of Chars Obtained in the Pyrolysis of Plastics, Tire Rubber and Forestry Biomass Wastes
AbstractThe present work aims to perform a characterization of chars obtained in the co-pyrolysis of waste mixtures composed by plastics, tires and pine biomass, to provide knowledge about the composition, leaching behavior and risk assessment of these materials in order to define strategies for their possible valorization or safe disposal. The chars were submitted to sequential solvent extractions with organic solvents of increasing polarity that allow the recovery of significant amounts of the pyrolysis oils trapped in the crude chars improving the yield of the pyrolysis liquids. An acidic demineralization procedure was successfully applied to the chars and high efficiency removals of the majority of the heavy metals were achieved. The demineralization study also demonstrated that hazardous heavy metals such as chromium, nickel and cadmium are significantly immobilized in the char matrix, and other heavy metals of concern such as zinc and lead will not represent a leaching problem if acidic conditions were not used. The obtained chars present sufficient quality and characteristics to be used as fuel or alternatively, to be used as adsorbents or precursors of activated carbon
Magnesium aminoclays as plasmid delivery agents for non-competent Escherichia coli JM109 transformation
Magnesium aminoclays were synthesized and used to transform non-competent Escherichia coli JM109 using the exogenous plasmid pUC19. The structure determined for the Mg aminoclays is analogous to 2:1 trioctahedral smectites such as talc, with an approximate composition R8Si8Mg6O16(OH)4, where R = CH2CH2NH2, morphologically arranged in layered sheets. Mg aminoclays were employed as a cationic vehicle that enabled the passage of plasmids across the cell envelope and led to genetic modification of the host. A stock solution of 10 mg/mL of Mg aminoclays was prepared, mixed with E. coli JM109 and pUC19 plasmid, and spread over Petri dishes containing lysogeny broth (LB), isopropyl ?-D-1-thiogalactopyranoside (IPTG), 5-bromo-4-chloro-3-indolyl-?-D-galactopyranoside (X-gal), ampicillin and various concentrations of agar (14%). The transformation efficiency obtained was higher for 1% and 2% agar even though transformation also occurred at agar concentrations of 3% and 4%. The optical density of E. coli JM109 and spreading time were also adjusted, favoring transformation when cells were used in their exponential growth phase (OD600 = 1.0) and spread for 90 s. Transformation was confirmed by the growth of blue colonies in LB/IPTG/X-gal/agar Petri dishes containing ampicillin, by regrowth of biomass in liquid media containing ampicillin and by agarose gel electrophoresis of the linearized pUC19 plasmid that followed plasmidic DNA extraction from 4 blue colonies. The maximum transformation efficiency achieved was 7.0 × 103 CFU/?g pUC19. This transformation approach proved to be suitable for a convenient, cost-effective, room-temperature, risk-free and rapid transformation of non-competent E. coli JM109.This study was supported by the Portuguese Foundation for Science and Technology (FCT) and the European Community fund FEDER, through Program COMPETE, under the scope of the Projects FCOMP-01-
0124-FEDER-007025 (PTDC/AMB/68393/2006), PEst-OE/EQB/LA0023/2013, UID/FIS/04650/2020, RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462) and the Project “BioEnv - Biotech nology and Bioengineering for a sustainable world”. The authors acknowledge the fellowship SFRH/BD/71661/2010 awarded to Gabriel Mendes under the scope of the MIT-Portugal Program. The authors also thank Paul Brown and Takuya Harada for the help in obtaining TEM images.info:eu-repo/semantics/publishedVersio
Hyperglycemia and Hyperinsulinemia-Like Conditions Independently Induce Inflammatory Responses in Human Chondrocytes
To elucidate the mechanisms by which type 2 Diabetes Mellitus (DM2) constitutes a risk
factor for the development and progression of osteoarthritis (OA), this work determined whether
high glucose and/or high insulin, the hallmarks of DM2, are capable of activating the transcription
factor, Nuclear Factor-κB (NF-κB), which plays a critical role in OA by inducing the expression of
pro-inflammatory and catabolic genes. For this, we analyzed NF-κB activation by measuring the
nuclear levels of p65 by western blot. As readouts of NF-κB activity, Interleukin-1β, Tumor Necrosis
Factor-α, and inducible nitric oxide synthase (iNOS) expression were analyzed by real time RT-PCR
and western blot. Culture of the human chondrocytic cell line, C28-I2, in high glucose (30 mM)
increased nuclear NF-κB p65 levels in a time-dependent manner, relative to cells cultured in medium
containing 10 mM glucose (regular culture medium). High glucose-induced NF-κB activation was
inhibited by co-treatment with its specific inhibitor, Bay 11-7082, 5 µM. Culture of primary human
chondrocytes under high glucose for 24 h increased IL-1β and TNF-α mRNA levels by 97% (p = 0.0066)
and 85% (p = 0.0045), respectively, while iNOS mRNA and protein levels and NO production increased
by 61% (p = 0.0017), 148% (p = 0.0089), and 70% (p = 0.049), respectively, relative to chondrocytes
maintained in 10 mM glucose. Treatment of chondrocytic cells with 100 nM insulin was also sufficient
to increase nuclear NF-κB p65 levels, independently of the glucose concentration in the culture
medium. This study shows that hyperglycemia and hyperinsulinemia are independently sufficient to
induce inflammatory responses in human chondrocytes, namely by activating NF-κB. This can be a
relevant mechanism by which DM type 2 and other conditions associated with impaired glucose and
insulin homeostasis, like obesity and the metabolic syndrome, contribute to the development and
progression of OA.info:eu-repo/semantics/publishedVersio
Antimicrobial activity and lipid profile of seaweed extracts from the North Portuguese coast
Seaweeds or marine macroalgae are a potential renewable resource in the marine environment and can represent a source of new natural compounds for human nutrition. This experimental work focused on the selection of a suitable extraction method, using Gracilaria vermiculophylla as a model, followed by the characterization of the antimicrobial activity of different solvent extracts of Gracilaria vermiculophylla, Porphyra dioica and Chondrus crispus, both from wild and from an integrated multi-trophic aquaculture system (IMTA), collected in the north of Portugal. Additionally, the fatty acid profile of the seaweed extracts was also investigated. Extraction tests included the definition of the physical state of the seaweed, temperature and type of solvents to be used during the process. Results revealed that test organisms (Gram negative and Gram positive bacteria as well as one yeast species) were more sensitive to extracts obtained with dried algae, processed continuously at higher temperatures. Results from antimicrobial activity of wild and IMTA seaweed extracts showed stronger antimicrobial activity in extracts of ethyl acetate when compared with those from methanol and diethyl ether; furthermore, among the type of microorganisms tested, there was tendency for inhibition of the Gram positive ones. In general, there appears to be a higher antimicrobial activity for the microorganisms under study in extracts obtained from aquaculture species, when compared with the wild ones. The fatty acid profile of ethyl acetate extracts revealed a predominance of saturated fatty acids (SFA), especially palmitic acid (16:0), followed by polyunsaturated fatty acids (PUFA) and monounsaturated fatty acids (MUFA). A higher content of fatty acids in aquaculture extracts of Gracilaria vermiculophylla and Porphyra dioica was also observed.info:eu-repo/semantics/publishedVersio
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