950 research outputs found
Demonstration of microRNA using in situ hybridisation on formalin fixed paraffin wax samples using conventional oligonucleotide probes: a comparison with the use of locked nucleic acid probes
Background: MicroRNAs (miRNA) regulate the translation of mRNA during gene expression and investigations have highlighted their importance in pathophysiology. qRT-PCR is currently the gold standard method for detecting changes in miRNA expression. However, when used on heterogeneous samples, it cannot identify individual cell types harbouring miRNAs. For this, in situ hybridisation (ISH) can be used. ISH methods using locked nucleic acid (LNA) probes have been shown to give reliable results in formalin fixed paraffin embedded (FFPE) samples. In this study their use has been directly compared with conventional oligonucleotide probes (COP) for ISH.
Methods: FFPE samples of colorectal adenocarcinoma, squamous carcinoma of lung and cases of invasive breast carcinoma were used to evaluate COP and LNA methods for the demonstration of miR-126 and miR-205. To demonstrate the utility of the COP method demonstration of miR-21 in 19 Gleason stage 7 prostate biopsy FFPE tissues was also undertaken. The demonstration of miR-21 by ISH in high and low expressing prostate cancer cell lines was also compared with qRT-PCR.
Results: Similar results were obtained using the COP and LNA ISH methods for the demonstration of miR-126 and miR-205. miR-21 was successfully demonstrated in the prostate cancer samples by COP ISH and expression levels of the miRNA demonstrated in the cell lines corresponded with qRT-PCR.
Conclusion: This study has shown that simplification of ISH protocols by the use of COPs provides equivalent results to the use of LNA methods and it can be used to precisely identify cells in which miRNA are expressed
A ventilação forçada na protecção contra a geada de fruteiras caducifólias
A geada em Portugal e particularmente nas regiões do interior norte e centro
provoca, frequentemente, danos em fruteiras caducifólias importantes como a
macieira, cerejeira e amendoeira. O rendimento dos agricultores é severamente
afectado e a não estabilização das produções tem igualmente consequências ao
nível das empresas e cooperativas do sector. Além da redução da produção, a
geada provoca deformações e outros defeitos nos frutos, diminuindo
consequentemente o seu valor comercial.
A minimização de potenciais prejuízos pode fazer-se através da
implementação de medidas preventivas (protecção passiva) e actuando
imediatamente antes ou durante a noite de geada (protecção activa) (Snyder &
de Melo-Abreu, 2005). Nos métodos indirectos ou passivos – de carácter
preventivo – podem-se destacar entre outros a selecção e melhoramento da
cultura, selecção do local de cultura, utilização da espécie/variedade adequada
ao local, modificação da paisagem com o fim de actuar sobre o microclima,
modificação dos sistemas de condução, e actuação sobre o solo e sua cobertura
(p. ex., supressão de infestantes). Os métodos directos ou activos – de carácter
protector – e de implementação temporária, assentam na previsão da
ocorrência de geada. Podem-se destacar os seguintes métodos: utilização de
coberturas sobre as culturas; utilização de nevoeiros artificiais; aquecimento
directo do ar; ventilação forçada; e métodos que se baseiam na libertação do
calor latente de fusão de água (rega por aspersão)
Simple multiplexing scheme for fibre optic grating sensor network
A new approach for the interrogation of a large number of fiber-optic grating sensors is proposed and demonstrated for a small number of sensors in which signal recovery is achieved by matching a receiving grating to its corresponding sensor. This technique is demonstrated for both quasi-static and periodic measurands, and the resolution achieved for a single sensor-receiving grating pair for quasi-static strain of 4.12µε
Possible Z2 phase and spin-charge separation in electron doped cuprate superconductors
The SU(2) slave-boson mean-field theory for the tt'J model is analyzed. The
role of next-nearest-neighbor hopping t' on the phase-diagram is studied. We
find a pseudogap phase in hole-doped materials (where t'<0). The pseudo-gap
phase is a U(1) spin liquid (the staggered-flux phase) with a U(1) gauge
interaction and no fractionalization. This agrees with experiments on hole
doped samples. The same calculation also indicates that a positive t' favors a
Z2 state with true spin-charge separation. The Z2 state that exists when t' >
0.5J can be a candidate for the pseudo-gap phase of electron-doped cuprates (if
such a phase exists). The experimental situation in electron-doped materials is
also addressed.Comment: 6 pages, 2 figures, RevTeX4. Homepage http://dao.mit.edu/~wen
Microstructures, geochemistry, and geochronology of mica fish: Review and advances
Shear zones are one of the most conspicuous structures in orogenic and rifting settings, accommodating high strain, rock displacement and influencing magma emplacement and fluid flow. Since shear zones may be simultaneously or sequentially affected by multiple processes involving mineral reactions, variations in pressure-temperature conditions, fluid-rock interaction, and diffusion, determining the timing of such structures has been one of the major challenges for modern geochronology. Although low- (up to lower greenschist facies) and high-temperature shear zones (above amphibolite facies) are well-dated through low- and high-closure temperature minerals, medium-temperature shear zones developed within the critical temperature window of ∼450–550 °C, in which conventional chronometers such as 40Ar/39Ar and Rb–Sr applied to mica fish may or may not record the timing of deformation for multiple reasons (e.g., grain size, cooling rate, mineral composition, fluid activity, deformation, neo- and recrystallization). Here, we review the current knowledge on the evolution of mica fish and the effect of deformation on its chemical and isotopic systems. We evaluate the effect on the widely deployed in situ 40Ar/39Ar technique. Furthermore, we demonstrate the potential to assess mica fish evolution applying high-spatial resolution microstructural and chemical mapping techniques such as electron backscatter diffraction (EBSD), time-of-flight secondary ion mass spectrometry (ToF–SIMS) and in situ Rb–Sr via triple quadrupole inductively coupled plasma mass spectrometry (TQ-ICP-MS) to a case study of medium-temperature mylonites from the well-characterized Taxaquara shear zone, SE Brazil. We show that mica fish display complex microstructures with variable strain intensity, commonly with low strain inner cores and high strain edges and along kink planes. Strain shadows in mica fish are commonly characterized by low-strain fine-grained muscovite, suggesting recrystallization coeval with ductile deformation. Despite being intensely deformed, muscovite fish Rb–Sr retain the protolith age (c. 600 Ma), whereas recrystallized fine-grained muscovite yields the timing of deformation (c. 550–540 Ma). Synthetic shear bands cross-cutting coarse-grained muscovite fish induce muscovite recrystallization consistent with their distinct chemistry, with recrystallized muscovite characterized by higher Fe–Mg and lower Na suggesting fluid-assisted recrystallization under lower temperature compared to the muscovite fish host. We propose that these shear bands across mica fish play an important role by accommodating grain size reduction and subsequent deformation, leading to the formation of smaller individual mica fish. Grain size reduction, likely enhanced by dynamic precipitation (i.e., coeval crystal-plastic deformation and dissolution-precipitation creep), appears as the key recrystallization mechanism that allows low strain muscovite in strain shadows and shear bands to record the timing of deformation in medium-temperature shear zones, consistent with qualitative Sr diffusion modelling
Poly(vinylidene fluoride) and copolymers as porous membranes for tissue engineering applications
Poly(vinylidene fluoride) (PVDF) and its main copolymers - poly(vinylidene fluoride-co-hexafluoropropene), P(VDF-HFP), and poly(vinylidene fluoride-co-trifluoroethylene), P(VDF-TrFE) - were processed by solvent casting at room temperature in the form of porous membranes. Copolymer membranes showed higher degree of porosity than PVDF, the average pore size being larger for P(VDF-TrFE) than for P(VDF-HFP) and PVDF. All membranes show high hydrophobicity with water contact angles in the range 94° to 115°, and electroactive beta phase contents above 90%. The adhesion and proliferation of both C2C12 myoblast and MC3T3-E1 pre-osteoblast cells on the membranes were investigated. It is demonstrated that PVDF membranes promote higher cell proliferation while P(VDF-HFP) membranes show the lowest proliferation for both kinds of cell. The proliferation on P(VDF-TrFE) membranes is cell dependent, higher for MC3T3-E1 cells but lower for C2C12 cells, related to the effect of the highly porous structure on the preferred morphology of each cell type, as the higher pore size and porosity of the P(VDF-TrFE) membrane induce cell elongation, which is preferred just by the C2C12 muscle cells.Funded by FEDER funds through the “Programa Operacional Fatores de Competitividade e
COMPETE” and by national funds arranged by FCT Fundação para a Ciência e a Tecnologia, project references PTDC/CTM-NAN/112574/2009 and PEST-C/FIS/UI607/2014.
Funding from “MateproOptimizing Materials and Processes”, ref. NORTE-07-0124-FEDER-000037”, co-funded by the “Programa Operacional Regional do Norte” (ON.2 e O Novo Norte), under the “Quadro de Referência Estrategico Nacional” (QREN), through the “Fundo Europeu de Desenvolvimento Regional” (FEDER). FCT for the SFRH/BPD/90870/2012 grant
Cholinergic modulation of striatal microcircuits
The purpose of this review is to bridge the gap between earlier literature on striatal cholinergic interneurons and mechanisms of microcircuit interaction demonstrated with the use of newly available tools. It is well known that the main source of the high level of acetylcholine in the striatum, compared to other brain regions, is the cholinergic interneurons. These interneurons provide an extensive local innervation that suggests they may be a key modulator of striatal microcircuits. Supporting this idea requires the consideration of functional properties of these interneurons, their influence on medium spiny neurons, other interneurons, and interactions with other synaptic regulators. Here, we underline the effects of intrastriatal and extrastriatal afferents onto cholinergic interneurons and discuss the activation of pre- and postsynaptic muscarinic and nicotinic receptors that participate in the modulation of intrastriatal neuronal interactions. We further address recent findings about corelease of other transmitters in cholinergic interneurons and actions of these interneurons in striosome and matrix compartments. In addition, we summarize recent evidence on acetylcholine-mediated striatal synaptic plasticity and propose roles for cholinergic interneurons in normal striatal physiology. A short examination of their role in neurological disorders such as Parkinson\u27s, Huntington\u27s, and Tourette\u27s pathologies and dystonia is also included
BB Intermeson Potentials in the Quark Model
In this paper we derive quark model results for scattering amplitudes and
equivalent low energy potentials for heavy meson pairs, in which each meson
contains a heavy quark. This "BB" system is an attractive theoretical
laboratory for the study of the nuclear force between color singlets; the
hadronic system is relatively simple, and there are lattice gauge theory (LGT)
results for V_BB(r) which may be compared to phenomenological models. We find
that the quark model potential (after lattice smearing) has qualitative
similarities to the LGT potential in the two B*B* channels in which direct
comparison is possible, although there is evidence of a difference in length
scales. The quark model prediction of equal magnitude but opposite sign for I=0
and I=1 potentials also appears similar to LGT results at intermediate r. There
may however be a discrepancy between the LGT and quark model I=1 BB potentials.
A numerical study of the two-meson Schrodinger equations in the (bqbar)(bqbar)
and (cqbar)(cqbar) sectors with the quark model potentials finds a single
"molecule", in the I=0 BB* sector. Binding in other channels might occur if the
quark model forces are augmented by pion exchange.Comment: 30 pages, 5 figures, revtex and epsfig. Submitted to Phys. Rev.
Control of bovine brucellosis from persistently infected holdings using RB51 vaccination with test-and-slaughter : a comparative case report from a high incidence area in Portugal
Bovine brucellosis due to Brucella abortus infection causes significant reproduc-tive and production losses in cattle and is a
major zoonosis. Eradication of this disease has proved difficult to achieve in Portugal where it still occurs in some regions
despite an ongoing national eradication programme. In 2004, the Alent-ejo region, a major cattle producing area, reported
one of the highest levels of bovine brucellosis in the country, especially in one divisional area. In that area, bovine brucellosis
was particularly problematic in a holding of ten herds, the largest extensive cattle unit in the country, which remained infected
despite an extensive test-and-slaughter programme and depopulation of five herds. A 5-year programme of RB51 vaccination
with biannual test-and-slaughter was thus implemented in 2004. The apparent animal seroprevalence decreased from 19%
(646/3,400) to 3% (88/2930) on the third herd-level test and remained below 0.8% (27/3324) after the fourth test. After the
tenth test, the holding had a prevalence of 0.1% (2/2332) and only one herd remained positive with a within-herd prevalence
of 1.1% (2/177). The results were compared to all other herds (n = 10) in the divisional area that were also persistently
infected but were subject only to test-and-slaughter before being depopulated. In these herds, the strategy of test-andslaughter
did not reduce the prevalence, which remained significantly higher than the vaccinated group (median = 0.48% and
8.5% in vaccinated versus non-vaccinated herds; Wilcoxon rank sum test; P < 0.01). The success of this pilot programme in
continental Portugal pro-vided a valuable case study to the official veterinary services by illustrating the value of RB51
vaccination with parallel testing and improved biosecurity as a comprehensive and sustainable strategy for bovine brucellosis
control in persis-tently infected herds.http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1865-16822015-04-30hb201
Comparison of oral versus sublingual piroxicam during postoperative pain management after lower third molar extraction
AbstractIn this study, 53 patients received piroxicam, administered orally or sublingually, after undergoing removal of symmetrically positioned lower third molars, during two separate appointments. This study used a randomized, blind, cross-over protocol. Objective and subjective parameters were recorded for comparison of postoperative results for 7 days after surgery. Patients treated with oral or sublingual piroxicam reported low postoperative pain scores. The patients who received piroxicam orally took a similar average amount of analgesic rescue medication compared with patients who received piroxicam sublingually (p>0.05). Patients exhibited similar values for mouth opening measured just before surgery and immediately following suture removal 7 days later (p>0.05), and showed no significant differences between routes of piroxicam administration for swelling control during the second or seventh postoperative days (p>0.05). In summary, pain, trismus and swelling after lower third molar extraction, independent of surgical difficulty, could be controlled by piroxicam 20mg administered orally or sublingually and no significant differences were observed between the route of delivery used in this study
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