750 research outputs found
Comparative mapping of a new repetitive DNA sequence and chromosome region-specific probes unveiling rearrangements in an Amazonian frog complex
The frog species Physalaemus ephippifer exists in the Amazonian region and harbors heteromorphic Z and W chromosomes. A genetic lineage closely related to this species was recognized based on its mitochondrial DNA and RADseq-style markers, but its taxonomic status is still unclear and has been referred to as Lineage 1 of âP. cuvieriâ. The heteromorphic sex chromosomes found in P. ephippifer are not present in this lineage and which of its chromosome pairs is homologous to the sex chromosomes of P. ephippifer remain to be elucidated as well as the role of such a karyotypic divergence in the evolution of these frogs. Here, we described a new family of repetitive DNA and used its chromosomal sites along with the markers detected by a probe constructed from the microdissected segment of the Z chromosome of P. ephippifer to infer chromosomal homology. We also analyzed an unnamed species that is considered to be the sister group of the clade composed of Lineage 1 of âP. cuvieriâ and P. ephippifer. Our results suggest that complex rearrangements involving the chromosomes that were inferred to be homeologous to the sex chromosomes of P. ephippifer have occurred during the divergence of this group of frogs.La grenouille Physalaemus ephippifer est prĂ©sente en Amazonie et elle comporte des chromosomes hĂ©tĂ©romorphes Z et W. Une lignĂ©e gĂ©nĂ©tiquement proche a Ă©tĂ© identifiĂ©e sur la base de son ADN mitochondrial et de marqueurs de type RADseq, mais sa taxonomie demeure incertaine tout en Ă©tant nommĂ©e LignĂ©e 1 du « P. cuvieri ». Les chromosomes sexuels hĂ©tĂ©romorphes prĂ©sents chez le P. ephippifer ne le sont pas au sein de cette lignĂ©e et il demeure inconnu laquelle des paires de chromosomes est homologue aux chromosomes sexuels du P. ephippifer de mĂȘme que le rĂŽle dâune telle divergence caryotypique dans lâĂ©volution de ces grenouilles. Dans ce travail les auteurs dĂ©crivent une nouvelle famille dâADN rĂ©pĂ©tĂ© et ils emploient les sites chromosomiques de ces sĂ©quences ainsi que des marqueurs dĂ©tectĂ©s au moyen dâune sonde dĂ©rivĂ©e dâun segment (obtenu par microdissection) du chromosome Z du P. ephippifer pour dĂ©terminer lâhomologie chromosomique. Les auteurs ont Ă©galement analysĂ© une espĂšce sans nom qui est considĂ©rĂ©e comme un groupe proche du clade composĂ© de la LignĂ©e 1 du « P. cuvieri » et du P. ephippifer. Les rĂ©sultats suggĂšrent que des rĂ©arrangements complexes, impliquant les chromosomes dĂ©terminĂ©s comme Ă©tant homĂ©ologues des chromosomes sexuels du P. ephippifer, seraient survenus au cours de la divergence au sein de ce groupe de grenouilles.Fil: Gatto, Kaleb Pretto. Universidade Estadual Do Campinas. Instituto de Biologia. Departamento de Biologia Estructural y Funcional. Laboratorio de Estudios Cromossomicos.; BrasilFil: Souza, Lucas H.B.. Universidade Estadual Do Campinas. Instituto de Biologia. Departamento de Biologia Estructural y Funcional. Laboratorio de Estudios Cromossomicos.; BrasilFil: Nascimento, Juliana. Universidade Estadual Do Campinas. Instituto de Biologia. Departamento de Biologia Estructural y Funcional. Laboratorio de Estudios Cromossomicos.; BrasilFil: Suarez, Pablo. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Nordeste. Instituto de BiologĂa Subtropical. Instituto de BiologĂa Subtropical - Nodo Puerto IguazĂș | Universidad Nacional de Misiones. Instituto de BiologĂa Subtropical. Instituto de BiologĂa Subtropical - Nodo Puerto IguazĂș; ArgentinaFil: Lourenço, Luciana Bolsoni. Universidade Estadual Do Campinas. Instituto de Biologia. Departamento de Biologia Estructural y Funcional. Laboratorio de Estudios Cromossomicos.; Brasi
Oligothiophene/graphene supramolecular ensembles managing light induced processes: Preparation, characterization, and femtosecond transient absorption studies leading to chargeâseparation
Advances in organic synthetic chemistry combined with the exceptional electronic properties of carbon allotropes, particularly graphene, is the basis to design and fabricate novel electron donor-Ââacceptor ensembles with desired properties for technological applications. Thiophene-Ââbased materials, mainly thiophene-Ââcontaining polymers, are known for their notable electronic properties. In this frame moving from polymer to oligomer forms, new fundamental information would help to the better understanding of their electrochemical and photophysical properties. Furthermore, a successful combination of their electronic properties with those of graphene is a challenging goal. In this work two oligothiophene compounds consists of three and nine thiophene-Âârings, abbreviated as 3T and 9T, respectively, were synthesized and noncovalently associated with liquid phase exfoliated few-Ââlayered graphene sheets (abbreviated as eG), forming donor-Ââacceptor 3T/eG and 9T/eG nanoensembes. Markedly, intra-Ââensemble electronic interactions between the two components in the ground and excited states were evaluated with the aid of UV-ÂâVis and photoluminescence spectroscopy. Furthermore, redox assays revealed an one-Ââelectron oxidation of 3T accompanied by one-Ââelectron reduction due to eG in 3T/eG, while two reversible one-Ââelectron oxidations of 9T accompanied by one-Ââelectron reduction of eG 9T/eG. The electrochemical band gap for 3T/eG and 9T/eG ensembles were calculated and verified that the negative free-Ââenergy change for the charge-Ââseparated state of 3T/eG and 9T/eG via the singlet excited state of 3T and 9T respectively, were thermodynamically favorable. Finally, results of transient pump-Ââprobe spectroscopic studies at the femtosecond time scale were supportive of charge transfer type interactions in the 3T/eG and 9T/eG ensembles. The estimated rates for intra-Ââensemble charge separation were found to be 9.52 x 109 s-Ââ1 and 2.2 x 1011 s-Ââ1, respectively, for 3T/eG and 9T/eG in THF, revealing moderate to ultrafast photoinduced events in the oligothiophene/graphene supramolecular ensemble
Hydroalcoholic extracts of Vellozia squamata: study of its nanoemulsions for pharmaceutical or cosmetic applications
AbstractSome species of plants are notable for the wide range of biologically active constituents in their tissues. Chemical and pharmacological studies of Vellozia squamata Pohl, Velloziaceae, popularly known in Brasil as âcanela-de-emaâ are scarce, but showed the presence of di-and triterpenoid that may be of scientii c interest. In the present study the hydroalcoholic extracts from leafs and stems of V. squamata were submitted to phytochemical prospection to identify the principal groups of constituents, and the antioxidant activity was determined by DPPH method. The hydroethanolic extracts presented higher antioxidant activity. Thus, nanoemulsion formulations were prepared using the method of phase inversion. Accelerated stability tests, such as heat stress and centrifugation were made, and physical and chemical properties of the nanoemulsions were established. Stable formulations were obtained from both extracts from leafs and stems. By the results was possible to establish the potential application of hydroalcoholic extracts from V. squamata in development of products with antioxidant properties and demonstrate a promising pharmaceutical produc
Comparison of the reliability of multifocal visual evoked cortical potentials generated by pattern reversal and pattern pulse stimulation
This study compared the effectiveness of the multifocal visual evoked cortical potentials (mfVEP) elicited by pattern pulse stimulation with that of pattern reversal in producing reliable responses (signal-to-noise ratio >1.359). Participants were 14 healthy subjects. Visual stimulation was obtained using a 60-sector dartboard display consisting of 6 concentric rings presented in either pulse or reversal mode. Each sector, consisting of 16 checks at 99% Michelson contrast and 80 cd/mÂČ mean luminance, was controlled by a binary m-sequence in the time domain. The signal-to-noise ratio was generally larger in the pattern reversal than in the pattern pulse mode. The number of reliable responses was similar in the central sectors for the two stimulation modes. At the periphery, pattern reversal showed a larger number of reliable responses. Pattern pulse stimuli performed similarly to pattern reversal stimuli to generate reliable waveforms in R1 and R2. The advantage of using both protocols to study mfVEP responses is their complementarity: in some patients, reliable waveforms in specific sectors may be obtained with only one of the two methods. The joint analysis of pattern reversal and pattern pulse stimuli increased the rate of reliability for central sectors by 7.14% in R1, 5.35% in R2, 4.76% in R3, 3.57% in R4, 2.97% in R5, and 1.78% in R6. From R1 to R4 the reliability to generate mfVEPs was above 70% when using both protocols. Thus, for a very high reliability and thorough examination of visual performance, it is recommended to use both stimulation protocols
Lessons from the terra preta de Ăndios of the amazon region for the utilisation of charcoal for soil amendment
peer-reviewedThe potential of charcoal and of partially combusted organic waste to mimic the soil organic matter of the Terras Pretas de Ăndios (Amazonian Dark Earths) from the Amazon Region is discussed. These materials serve as soil conditioners and as sequesterers of carbon in recalcitrant and in reactive forms. Studies carried out by Brazilian and by international groups have contributed to the emergence of an awareness of the compositions and of the uses of these materials. In this contribution we report on chemical studies that are leading to the development of a scientific and technological awareness, and of innovations that will have value in finding novel uses in applications
to soil of chars from organic wastes such as those from the biofuel industry, and from metallurgical and various coal plant residues
Measurement of the p-pbar -> Wgamma + X cross section at sqrt(s) = 1.96 TeV and WWgamma anomalous coupling limits
The WWgamma triple gauge boson coupling parameters are studied using p-pbar
-> l nu gamma + X (l = e,mu) events at sqrt(s) = 1.96 TeV. The data were
collected with the DO detector from an integrated luminosity of 162 pb^{-1}
delivered by the Fermilab Tevatron Collider. The cross section times branching
fraction for p-pbar -> W(gamma) + X -> l nu gamma + X with E_T^{gamma} > 8 GeV
and Delta R_{l gamma} > 0.7 is 14.8 +/- 1.6 (stat) +/- 1.0 (syst) +/- 1.0 (lum)
pb. The one-dimensional 95% confidence level limits on anomalous couplings are
-0.88 < Delta kappa_{gamma} < 0.96 and -0.20 < lambda_{gamma} < 0.20.Comment: Submitted to Phys. Rev. D Rapid Communication
Measurement of the ttbar Production Cross Section in ppbar Collisions at sqrt{s} = 1.96 TeV using Kinematic Characteristics of Lepton + Jets Events
We present a measurement of the top quark pair ttbar production cross section
in ppbar collisions at a center-of-mass energy of 1.96 TeV using 230 pb**{-1}
of data collected by the DO detector at the Fermilab Tevatron Collider. We
select events with one charged lepton (electron or muon), large missing
transverse energy, and at least four jets, and extract the ttbar content of the
sample based on the kinematic characteristics of the events. For a top quark
mass of 175 GeV, we measure sigma(ttbar) = 6.7 {+1.4-1.3} (stat) {+1.6- 1.1}
(syst) +/-0.4 (lumi) pb, in good agreement with the standard model prediction.Comment: submitted to Phys.Rev.Let
Measurement of the ttbar Production Cross Section in ppbar Collisions at sqrt(s)=1.96 TeV using Lepton + Jets Events with Lifetime b-tagging
We present a measurement of the top quark pair () production cross
section () in collisions at TeV
using 230 pb of data collected by the D0 experiment at the Fermilab
Tevatron Collider. We select events with one charged lepton (electron or muon),
missing transverse energy, and jets in the final state. We employ
lifetime-based b-jet identification techniques to further enhance the
purity of the selected sample. For a top quark mass of 175 GeV, we
measure pb, in
agreement with the standard model expectation.Comment: 7 pages, 2 figures, 3 tables Submitted to Phys.Rev.Let
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