1,608 research outputs found
Primary CNS Lymphomas: Challenges in Diagnosis and Monitoring
Primary Central Nervous System Lymphoma (PCNSL) is a rare neoplasm that can involve brain, eye, leptomeninges, and rarely spinal cord. PCNSL lesions most typically enhance homogeneously on T1-weighted magnetic resonance imaging (MRI) and appear T2-hypointense, but high variability in MRI features is commonly encountered. Neurological symptoms and MRI findings may mimic high grade gliomas (HGGs), tumefactive demyelinating lesions (TDLs), or infectious and granulomatous diseases. Advanced MRI techniques (MR diffusion, spectroscopy, and perfusion) and metabolic imaging, such as Fluorodeoxyglucose Positron Emission Tomography (FDG-PET) or amino acid PET (usually employing methionine), may be useful in distinguishing these different entities and monitoring the disease course. Moreover, emerging data suggest a role for cerebrospinal fluid (CSF) markers in predicting prognosis and response to treatments. In this review, we will address the challenges in PCNSL diagnosis, assessment of response to treatments, and evaluation of potential neurotoxicity related to chemotherapy and radiotherapy
Самостійна робота з англійської мови для студентів І-го, ІІ-го курсів історичного факультету спеціальності «Політологія»
Методична розробка з англійської мови містить добірку текстів з політології та вправи до них.
Для студентів першого і другого курсів денної та заочної форми навчання історичного факультету
Cadmium-free Thin-Film Cu(In,Ga)Se2(In2S3) Heterophotoelements Fabrication and Properties
The method of heat treatment of metallic Cu–In–Ga layers in the N2 inert atmosphere in the presence of selenium and sulfur vapors was used to grow homogeneous films of Cu(In,Ga)(S,Se)2 alloys onto which the CdS or In2S3 films were deposited and, on the basis of these structures, the thin-film glass/Mo/p-Cu(In,Ga)(S,Se)2/n-(In2S3,CdS)/n-ZnO/Ni–Al photoelements were fabricated. The mechanisms of charge transport and the processes of photosensitivity in the obtained structures subjected to irradiation with natural and linearly polarized light are discussed. The broadband hotosensitivity of thin-film heterophotoelements and the induced photopleochroism were detected; these findings indicate that there is an interference-related blooming of the
structures obtained. It is concluded that it is possible to use ecologically safe cadmium-free thin-film heterostructures as high-efficiency photoconverters of solar radiation
Lower grade gliomas: relationships between metabolic and structural imaging with grading and molecular factors
Background: Positron emission tomography (PET) is a valuable tool for the characterization of brain tumors in vivo. However, few studies have investigated the correlation between carbon-11-methionine (11C-METH) PET metrics and the clinical, radiological, histological, and molecular features of patients affected by lower grade gliomas (LGGs). The present observational study evaluated the relationships between 11C-METH PET metrics and structural magnetic resonance imaging (MRI) findings with the histomolecular biomarkers in patients with LGGs who were candidates for surgery. Methods: We enrolled 96 patients with pathologically proven LGG (51 men, 45 women; age 44.1 \ub1 13.7 years; 45 with grade II, 51 with grade III), who had been referred from March 2012 to January 2015 for tumor resection and had undergone preoperative 11C-METH PET. The semiquantitative metrics for 11C-METH PET included maximum standardized uptake value (SUVmax), SUV ratio to normal brain, and metabolic tumor burden (MTB). The PET semiquantitative metrics were analyzed and compared with the MRI features, histological diagnosis, isocitrate dehydrogenase-1/2 status, and 1p/19q codeletion. Results: Histological grade was associated with SUVmax (P = 0.002), SUV ratio (P = 0.011), and MTB (P = 0.001), with grade III lesions showing higher values. Among the nonenhancing lesions on MRI, SUVmax (P = 0.001), SUV ratio (P = 0.003) and MTB (P < 0.001) were significantly different statistically for grade II versus grade III. The MRI lesion volume correlated poorly with MTB (r 2 = 0.13). The SUVmax and SUV ratio were greater (P < 0.05) in isocitrate dehydrogenase-1/2 wild-type lesions, and the SUV ratio was associated with the presence of the 1p19q codeletion. Conclusions: The 11C-METH PET metrics correlated significantly with histological grade and the molecular profile. Semiquantitative PET metrics can improve the preoperative evaluation of LGGs and thus support clinical decision-making
First Observation of the Doubly Charmed Baryon Xi_cc^+
We observe a signal for the doubly charmed baryon Xi_cc^+ in the charged
decay mode Xi_cc^+ --> Lambda_c^+ K- pi+ in data from SELEX, the charm
hadro-production experiment at Fermilab. We observe an excess of 15.9 events
over an expected background of 6.1 +/- 0.5 events, a statistical significance
of 6.3sigma. The observed mass of this state is (3519 +/- 1) MeV/c^2. The
Gaussian mass width of this state is 3MeV/c^2, consistent with resolution; its
lifetime is less than 33fsec at 90% confidence.Comment: 5 pages, 3 figures, accepted for publication in Physical Review
Letter
First Measurement of pi e -> pi e gamma Pion Virtual Compton Scattering
Pion Virtual Compton Scattering (VCS) via the reaction pi e --> pi e gamma
was observed in the Fermilab E781 SELEX experiment. SELEX used a 600 GeV/c pi-
beam incident on target atomic electrons, detecting the incident pi- and the
final state pi-, electron and gamma. Theoretical predictions based on chiral
perturbation theory are incorporated into a Monte Carlo simulation of the
experiment and are compared to the data. The number of reconstructed events (9)
and their distribution with respect to the kinematic variables (for the
kinematic region studied) are in reasonable accord with the predictions. The
corresponding pi- VCS experimental cross section is sigma=38.8+-13 nb, in
agreement with the theoretical expectation sigma=34.7 nb.Comment: 10 pages, 12 figures, 4 tables, 25 references, SELEX home page is
http://fn781a.fnal.gov/, revised July 21, 2002 in response to journal referee
Comment
First observation of a narrow charm-strange meson DsJ(2632) -> Ds eta and D0 K+
We report the first observation of a charm-strange meson DsJ(2632) at a mass
of 2632.6+/-1.6 MeV/c^2 in data from SELEX, the charm hadro-production
experiment E781 at Fermilab. This state is seen in two decay modes, Ds eta and
D0 K+. In the Ds eta decay mode we observe an excess of 49.3 events with a
significance of 7.2sigma at a mass of 2635.9+/-2.9 MeV/c^2. There is a
corresponding peak of 14 events with a significance of 5.3sigma at 2631.5+/-1.9
MeV/c^2 in the decay mode D0 K+. The decay width of this state is <17 MeV/c^2
at 90% confidence level. The relative branching ratio Gamma(D0K+)/Gamma(Dseta)
is 0.16+/-0.06. The mechanism which keeps this state narrow is unclear. Its
decay pattern is also unusual, being dominated by the Ds eta decay mode.Comment: 5 pages, 3 included eps figures. v2 as accepted for publication by
PR
Mechanistic studies on δ-aminolevulinic acid uptake and efflux in a mammary adenocarcinoma cell line
δ-aminolevulinic acid (ALA) is the precursor in the biosynthesis of porphyrins. The knowledge of both the regulation of ALA entrance and efflux from the cells and the control of porphyrin biosynthesis is essential to improve ALA-mediated photodynamic therapy. In this work, we studied the regulation of ALA uptake and efflux by endogenously accumulated ALA and/or porphyrins in murine mammary adenocarcinoma cells. Under our set of conditions, the haem synthesis inhibitor succinyl acetone completely prevented porphobilinogen and porphyrin synthesis from ALA, and led to an increase in the intracellular ALA pool. However, neither intracellular ALA nor porphyrin pools regulate ALA uptake or efflux during the first 15 min of the process. Based on temperature dependence data, ALA but not γ-aminobutyric acid (GABA) efflux is mediated by a diffusion mechanism. Moreover, the addition of extracellular GABA not only did not influence the rate of ALA efflux but on the contrary it affected ALA uptake, showing the contribution of a saturable mechanism for the uptake, but not for the efflux of ALA from the cells. © 2003 Cancer Research UK.Fil:Correa García, S. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Casas, A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Perotti, C. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Batlle, A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Bermúdez Moretti, M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina
Observation of the Cabibbo-suppressed decay Xi_c+ -> p K- pi+
We report the first observation of the Cabibbo-suppressed charm baryon decay
Xi_c+ -> p K- pi+. We observe 150 +- 22 events for the signal. The data were
accumulated using the SELEX spectrometer during the 1996-1997 fixed target run
at Fermilab, chiefly from a 600 GeV/c Sigma- beam. The branching fractions of
the decay relative to the Cabibbo-favored Xi_c+ -> Sigma+ K- pi+ and Xi_c+ ->
X- pi+ pi+ are measured to be B(Xi_c+ -> p K- pi+)/B(Xi_c+ -> Sigma+ K- pi+) =
0.22 +- 0.06 +- 0.03 and B(Xi_c+ -> p K- pi+)/B(Xi_c+ -> X- pi+ pi+) = 0.20 +-
0.04 +- 0.02, respectively.Comment: 5 pages, RevTeX, 3 figures (postscript), Submitted to Phys. Rev. Let
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