5,040 research outputs found
Rapid diagnosis of apple proliferation mycoplasma‐like organism using a polymerase chain reaction procedure
No full textThe rapid diagnosis of apple proliferation mycoplasma-like organism, using polymerase chain reaction amplification of part of the 16S rRNA gene is reported. Apple proliferation MLO can be detected in as little as 0.3 g of diseased tissue. Results compare favourably with those obtained by other PCR-based methods. Operational speed, sensitivity, specificity and ease of performance of the method, with particular reference to indexing purposes, are discussed
Probing proteins in solution by 129Xe NMR spectroscopy
No full textThe interaction of xenon with different proteins in aqueous solution is investigated by (129)Xe NMR spectroscopy. Chemical shifts are measured in horse metmyoglobin, hen egg white lysozyme, and horse cytochrome c solutions as a function of xenon concentration. In these systems, xenon is in fast exchange between all possible environments. The results suggest that nonspecific interactions exist between xenon and the protein exteriors and the data are analyzed in term of parameters which characterize the protein surfaces. The experimental data for horse metmyoglobin are interpreted using a model in which xenon forms a 1:1 complex with the protein and the chemical shift of the complexed xenon is reported (Locci et al. Keystone Symposia "Frontiers of NMR in Molecular Biology VI", Jan. 9--15, 1999, Breckenridge, CO, Abstract E216, p. 53; Locci et al. XeMAT 2000 "Optical Polarization and Xenon NMR of Materials", June 28--30, 2000, Sestri Levante, Italy, p. 46).SCOPUS: ar.jinfo:eu-repo/semantics/publishe
HLA-G intracellular expression in decidua trophoblasts in a normal term placenta: a confocal and transmission electron microscopy study.
No full textABSTRACT
The placenta acts as an immunological barrier between the
mother and the fetal “graft”, allowing two antigenically
different organisms to tolerate one another. Human
leukocyte antigen-G (HLA-G) may be involved in the
mechanisms modulating the maternal immune system.
Indeed, several authors have found that HLA-G is
primarily expressed on the placental trophoblast plasmatic
membrane.
However, pregnancy still remains a major immunological
enygma and current studies are far from clarifying the
mystery. To further investigate this matter, we undertook
the current study, using laser scanning confocal (LSCM)
and transmission electron microscopy (TEM), in order to
deepen knowledge on HLA-G expression in placentas
from normal pregnancies, following a spontaneous
term delivery. Unexpectedly, we observed that HLA-G
expression includes both vesicles and clusters, localized in
the cytosol or close to the nucleus.
Keywords: placenta, HLA-G, confocal microscopy,
transmission electron microscopy
A text classification framework based on optimized error correcting output code
No full textIn recent years, there has been increasing interest in using text classifiers for retrieving and filtering infomation from web sources. As the numbers of categories in this kind of software applications can be high, Error correcting Output Coding (ECOC) can be a valid approach to perform multi-class classification. This paper explores the use of ECOC for learning text classifiers using two kinds of dichotomizers and compares them to each corresponding monolithic classifier. We propose a simulated annealing approach to calculate the coding matrix using an energy function similar to the electrostatic potential energy of a system of charges, which allows to maximize the average distance between codewords |with low variance. In addition, we use a new criterion for selecting features, a feature (in this specific context) being any term that may occur in a document. This criterion defines a measure of discriminant capability and allows to order terms according to it. Three different measures have been experimented to perform feature ranking/selection, in a comparative setting. Experimental results show that reducing the set of features used to train classifiers does not affect classification performance. Notably, feature selection is not a preprocessing activity valid for all dichotomizers. In fact, features are selected for each dichotomizer that occurs in the matrix coding, typically giving rise to a different subset of features depending on the dichotomizers at hand
Muscle elastography: a new imaging technique for multiple sclerosis spasticity measurement
No full textMultiple sclerosis (MS) spasticity is currently evaluated on the basis of neurological examinations such as Ashworth Scale (AS) and 0–10 NRS. Severity of spasticity is difficult to quantify. We investigated the use of real time elastography (RTHE) ultrasounds for evaluating objectively the muscle fibers status in MS spasticity patients and their changes after a new antispasticity treatment. Two studies were performed. In study A, 110 MS patients underwent a neurological evaluation based on the AS and RTHE. The RTHE images were scored with the new 1-5 muscle fibers rigidity imaging scale, here called MEMSs (Muscle Elastography Multiple Sclerosis Score). The correlation between AS and MEMSs was found to be statistically significant. In study B, 55 MS patients treated with THC:CBD oromucosal spray for their resistant spasticity were followed prospectively. MS spasticity was evaluated by the 0–10 NRS scale at baseline and after 4 weeks of treatment. MEMSs’ figures were obtained at both timepoints. Responders to THC:CBD oromucosal spray (pre-defined as an improvement ≥20% in their 0–10 NRS spasticity score vs. baseline) were 65% of sample. These patients had a mean 0-10 NRS reduction of 1.87 and a MEMSs reduction of 1.97 (P values <0.0001). The remaining 35% of patients, classified as clinically non-responders, showed still a significant mean reduction in MEMSs (0.8, P = 0.002). Our overall results showed that RTHE, operativized throughout MEMSs, could be an objective gold standard to evaluate MS muscle spasticity as well as the effectiveness of antispasticity therapy
USE OF POLYMERASE CHAIN-REACTION TO PRODUCE OLIGONUCLEOTIDE PROBES FOR MYCOPLASMALIKE ORGANISMS
No full textModeling of Electric Current Assisted Sintering: An extended fluid-like approach for the description of powders rheological behavior
No full textA general theoretical framework for investigating the rheological behavior of powder undergoing electric current assisted consolidation is proposed in this work. The most relevant phenomena occurring during ECAS process are taken into account. Consolidating powders are assumed to behave as a viscous fluid. Specifically, powder viscosity is expressed by the Bird–Carreau–Yasuda's model, which includes the power-law creep description typically adopted in the ECAS modeling literature. The proposed stress-strain constitutive law allows one avoiding a priori assumptions regarding the powder rheological behavior. The resulting system of differential equations cannot be solved analytically, so that the finite-element method (FEM) numerical technique is adopted. A numerical investigation of the effect of some representative model parameters on powder consolidation is performed and the possible different rheological regimes correspondingly taking place are identified. Influence of the applied mechanical load and zero-shear rate viscosity is studied and a suitable approach to map out the powder rheological behavior is presented. It is found that powder rheological response is not only determined by the intrinsic material properties but also depends upon the process operating conditions. As an example, high values of mechanical load along with low values of zero-shear rate viscosity induce a nonlinear viscous flow while Newtonian (linear) flow takes place for low values of mechanical load associated to high values of zero-shear rate viscosity. The proposed model should be considered as a first attempt to extend the rheological theory of sintering recently proposed in the field of electric current assisted consolidation to a broader range of shear rates, which, in turn, extends the application of this theory to a wider variety of materials and operating conditions
Efficient implementation of the Yule-Simon stochastic process for modeling internet and software development activities
No full textWe develop three different algorithms for implementing the Preferential Attachment mechanism, with regards to the Yule process, able to describe how statistical power-law distributions, for various properties of OO software systems and of the internet, are generated. Since modern software systems have reached a huge dimension, counting tens, or hundreds of thousand, of units or modules, the efficiency of algorithms for their simulation is a critical issue. We discuss their efficiency for different parameters value, their scaling with system size, and analyze in which cases one is preferable with respect to the others
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