486 research outputs found
Compartmentalized Cerebral Metabolism of [1,6-13C]Glucose Determined by in vivo 13C NMR Spectroscopy at 14.1 T
Cerebral metabolism is compartmentalized between neurons and glia. Although glial glycolysis is thought to largely sustain the energetic requirements of neurotransmission while oxidative metabolism takes place mainly in neurons, this hypothesis is matter of debate. The compartmentalization of cerebral metabolic fluxes can be determined by 13C nuclear magnetic resonance (NMR) spectroscopy upon infusion of 13C-enriched compounds, especially glucose. Rats under light α-chloralose anesthesia were infused with [1,6-13C]glucose and 13C enrichment in the brain metabolites was measured by 13C NMR spectroscopy with high sensitivity and spectral resolution at 14.1 T. This allowed determining 13C enrichment curves of amino acid carbons with high reproducibility and to reliably estimate cerebral metabolic fluxes (mean error of 8%). We further found that TCA cycle intermediates are not required for flux determination in mathematical models of brain metabolism. Neuronal tricarboxylic acid cycle rate (VTCA) and neurotransmission rate (VNT) were 0.45 ± 0.01 and 0.11 ± 0.01 μmol/g/min, respectively. Glial VTCA was found to be 38 ± 3% of total cerebral oxidative metabolism, accounting for more than half of neuronal oxidative metabolism. Furthermore, glial anaplerotic pyruvate carboxylation rate (VPC) was 0.069 ± 0.004 μmol/g/min, i.e., 25 ± 1% of the glial TCA cycle rate. These results support a role of glial cells as active partners of neurons during synaptic transmission beyond glycolytic metabolism
Composição química e atividade antimicrobiana do óleo essencial de folhas e flores de Aloysia gratissima
Volatile oils from leaves and flowers of Aloysia gratissima were investigated for their chemical composition and antimicrobial activity against the bacteria Bacilus subtilis, Staphylococcus aureus, Salmonella choleraesuis, Pseudomonas aeruginosa, Streptococcus pneumoniae and the Candida albicans yeast. The minimum inhibitory concentrations (MIC) of the oils were determined by the micro-dilution method, while the chemical composition was determined by GC-MS (gas chromatography mass spectrometry). The fresh leaves and inflorescence were subjected to hydrodistillation for 120 min using a Clevenger-type apparatus, and the essential oil was tested against microorganisms. High concentrations of sesquiterpenes were observed for the inflorescence, and monoterpenes were observed for the leaves. The main compounds of the inflorescence essential oil were E-caryophyllene, germacrene B, guaiol and bulnesol, while in the leaves the main compounds were trans-pinocamphone, trans-pinocarveyl acetate, and guaiol. The essential oil from the leaves showed an effect against P. aeruginosa and S. pneumonia, and the essential oil of the inflorescence showed an effect against P. aeruginosa, S. pneumonia, and Candida albicans.O óleo essencial de folhas e de flores de Aloysia gratissima foi avaliado quanto à composição química e ação antimicrobiana contra as bactérias Bacilus subtilis, Staphylococcus aureus, Salmonella choleraesuis, Pseudomonas aeruginosa, Streptococcus pneumoniae, e a levedura Candida albicans. A concentração mínima inibitória (MIC) dos óleos essenciais foi determinada pelo método da microdiluição e a composição química determinada por CG-EM (Cromatografia Gasosa acoplada a Espectrômetro de Massas). Folhas e inflorescências frescas foram hidrodestiladas por 120 minutos em aparelho Clevenger sendo o óleo essencial testado contra microorganismos. Para as flores foi observada maior concentração de sesquiterpenos, enquanto que as folhas apresentaram maior concentração de monoterpenos. Os principais constituintes do óleo essencial da flor foram: E-cariofileno, germacreno B, guaiol e bulnesol; e das folhas foram: trans-pinocamfona, acetato de trans-pinocarveol e guaiol. O óleo essencial da folha mostrou atividade contra P. aeruginosa e S. pneumoniae, e o óleo essencial da flor mostrou atividade contra P. aeruginosa, S. pneumoniae e Candida albicans.583588Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES
Evaluation of Nanofiltration for the Treatment of Industrial Effluents Containing Anionic Surfactants
Some sources of variation in the assessment when introducing unaccounted mortality due to discarding practices. The case of Southern Four spot megrim stock.
Four spot megrim (Lepidorhombus boscii) is widely distributed in Atlantic waters form Iceland to
Cape Bojador. In ICES Divisions VIIIc and IXa, Portuguese and Spanish ships captured this
species as by-catch mainly in mixed bottom trawl fisheries. Only one exploitation unit of this
species is assessed (from Divisions VIIIc and IXa) in the ICES Working Group of Hake, Monk
and Megrim. Discard data are not used in the assessment of this species, though they are
considered significantly high for younger ages. Discards data are available for Spanish trawlers
for 1993, 1994, 1997, and the period from 1999 to 2001. A simulation using discard data was
made to avoid the underestimation of mortality and recruitment. Due to the change in January
1990 in the minimum legal size for this species in this area, it was decided not to use historical
information previous to this year, as it is supposed that this change could substantially affect the
fleet discard pattern. Different options were considered as the way of raising: by effort (number
of trips, hour of trawling) or by landings (in weight or in number). Reasons for the final choices
are explained for all options considered. The way to introduce discards data in the VPA
procedure for assessment was through the catch at age matrix since we considered that no fish
of this species survive after being discarded. Differences in yield of Short-term and Mediumterm
projections were observed
Mudança de paradigma no ensino da Bioquímica na licenciatura em Ciências da Nutrição na Universidade do Porto
No primeiro ano da licenciatura em Ciências da Nutrição, na Faculdade de Ciências da Nutriçãoe Alimentação, da Universidade do Porto, existem duas Unidades Curriculares que introduzem aBioquímica aos estudantes [Química Orgânica e Bioquímica I (no 1º e 2º semestres,respetivamente)] e cujos programas e modalidades pedagógicas estão inter-relacionados,confrontando o estudante, progressivamente ao longo do ano letivo, com oportunidades deaprendizagem ativa.A divulgação de descobertas científicas e o envolvimento dos estudantes em projetos deinvestigação científica melhoram a aprendizagem e a retenção de conhecimentos, assim comooperacionalizam a sua aplicabilidade prática, ao mesmo tempo que desenvolvem um efeitopositivo no interesse pela investigação científica.Com o objetivo de melhorar não só a aquisição de conhecimentos, mas também a compreensão e aplicabilidade dos mesmos, assim como o desenvolvimento de competências e de raciocíniohipotético-dedutivo pelos estudantes, o ensino da Bioquímica "tradicional/clássico/base" foimodificado de modo a: 1) introduzir a discussão de artigos científicos relevantes (nas sessõesteóricas e/ou práticas); 2) possibilitar o contacto com a investigação científica feita pelosdocentes (nas sessões teóricas) e 3) possibilitar a realização de pequenos projetos deinvestigação científica (nas sessões práticas). Nestas 3 modalidades pedagógicas estãosubjacentes temas bioquímicos que integram o programa "clássico/base" das referidas UnidadesCurriculares. Adicionalmente, ao estudante são divulgados, nas 3 modalidades pedagógicasacima referidas, temas atuais da Bioquímica Nutricional ao mesmo tempo que contacta comtodas as fases da metodologia de aquisição de conhecimentos, de raciocínio e de investigaçãousadas na área da Nutrição
Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV
Results are presented from a search for a W' boson using a dataset
corresponding to 5.0 inverse femtobarns of integrated luminosity collected
during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV.
The W' boson is modeled as a heavy W boson, but different scenarios for the
couplings to fermions are considered, involving both left-handed and
right-handed chiral projections of the fermions, as well as an arbitrary
mixture of the two. The search is performed in the decay channel W' to t b,
leading to a final state signature with a single lepton (e, mu), missing
transverse energy, and jets, at least one of which is tagged as a b-jet. A W'
boson that couples to fermions with the same coupling constant as the W, but to
the right-handed rather than left-handed chiral projections, is excluded for
masses below 1.85 TeV at the 95% confidence level. For the first time using LHC
data, constraints on the W' gauge coupling for a set of left- and right-handed
coupling combinations have been placed. These results represent a significant
improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe
Search for the standard model Higgs boson decaying into two photons in pp collisions at sqrt(s)=7 TeV
A search for a Higgs boson decaying into two photons is described. The
analysis is performed using a dataset recorded by the CMS experiment at the LHC
from pp collisions at a centre-of-mass energy of 7 TeV, which corresponds to an
integrated luminosity of 4.8 inverse femtobarns. Limits are set on the cross
section of the standard model Higgs boson decaying to two photons. The expected
exclusion limit at 95% confidence level is between 1.4 and 2.4 times the
standard model cross section in the mass range between 110 and 150 GeV. The
analysis of the data excludes, at 95% confidence level, the standard model
Higgs boson decaying into two photons in the mass range 128 to 132 GeV. The
largest excess of events above the expected standard model background is
observed for a Higgs boson mass hypothesis of 124 GeV with a local significance
of 3.1 sigma. The global significance of observing an excess with a local
significance greater than 3.1 sigma anywhere in the search range 110-150 GeV is
estimated to be 1.8 sigma. More data are required to ascertain the origin of
this excess.Comment: Submitted to Physics Letters
Measurement of the Lambda(b) cross section and the anti-Lambda(b) to Lambda(b) ratio with Lambda(b) to J/Psi Lambda decays in pp collisions at sqrt(s) = 7 TeV
The Lambda(b) differential production cross section and the cross section
ratio anti-Lambda(b)/Lambda(b) are measured as functions of transverse momentum
pt(Lambda(b)) and rapidity abs(y(Lambda(b))) in pp collisions at sqrt(s) = 7
TeV using data collected by the CMS experiment at the LHC. The measurements are
based on Lambda(b) decays reconstructed in the exclusive final state J/Psi
Lambda, with the subsequent decays J/Psi to an opposite-sign muon pair and
Lambda to proton pion, using a data sample corresponding to an integrated
luminosity of 1.9 inverse femtobarns. The product of the cross section times
the branching ratio for Lambda(b) to J/Psi Lambda versus pt(Lambda(b)) falls
faster than that of b mesons. The measured value of the cross section times the
branching ratio for pt(Lambda(b)) > 10 GeV and abs(y(Lambda(b))) < 2.0 is 1.06
+/- 0.06 +/- 0.12 nb, and the integrated cross section ratio for
anti-Lambda(b)/Lambda(b) is 1.02 +/- 0.07 +/- 0.09, where the uncertainties are
statistical and systematic, respectively.Comment: Submitted to Physics Letters
Search for new physics in events with opposite-sign leptons, jets, and missing transverse energy in pp collisions at sqrt(s) = 7 TeV
A search is presented for physics beyond the standard model (BSM) in final
states with a pair of opposite-sign isolated leptons accompanied by jets and
missing transverse energy. The search uses LHC data recorded at a
center-of-mass energy sqrt(s) = 7 TeV with the CMS detector, corresponding to
an integrated luminosity of approximately 5 inverse femtobarns. Two
complementary search strategies are employed. The first probes models with a
specific dilepton production mechanism that leads to a characteristic kinematic
edge in the dilepton mass distribution. The second strategy probes models of
dilepton production with heavy, colored objects that decay to final states
including invisible particles, leading to very large hadronic activity and
missing transverse energy. No evidence for an event yield in excess of the
standard model expectations is found. Upper limits on the BSM contributions to
the signal regions are deduced from the results, which are used to exclude a
region of the parameter space of the constrained minimal supersymmetric
extension of the standard model. Additional information related to detector
efficiencies and response is provided to allow testing specific models of BSM
physics not considered in this paper.Comment: Replaced with published version. Added journal reference and DO
Measurement of isolated photon production in pp and PbPb collisions at sqrt(sNN) = 2.76 TeV
Isolated photon production is measured in proton-proton and lead-lead
collisions at nucleon-nucleon centre-of-mass energies of 2.76 TeV in the
pseudorapidity range |eta|<1.44 and transverse energies ET between 20 and 80
GeV with the CMS detector at the LHC. The measured ET spectra are found to be
in good agreement with next-to-leading-order perturbative QCD predictions. The
ratio of PbPb to pp isolated photon ET-differential yields, scaled by the
number of incoherent nucleon-nucleon collisions, is consistent with unity for
all PbPb reaction centralities.Comment: Submitted to Physics Letters
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