121 research outputs found
Evaluación de los factores determinantes del recuento de plaquetas en pacientes con cirrosis
Thrombocytopenia is considered one of the hallmarks of patients with cirrhosis. Several mechanisms have been implicated in the pathophysiology of thrombocytopenia in cirrhosis. Hypersplenism caused by splenomegay, classically regarded as an indirect marker of portal hypertension has been considered the main factor implicated [200]. Nevertheless, portal hypertension is best estimated by the hepatic venous pressure gradient (HVPG) [32, 189], although contradictory results have been reported regarding the association between HVPG and platelet count [195-197]. The identification of thrombopoietin (TPO), a growth factor that enhances the maturation of megakaryocytes and the release of platelets from the bone marrow, has shed new light on the physiolgy of platelets [217]. In normal conditions in adults, TPO is mainly produced in the liver [93, 96] and the circulating leves of platelets are controlled by a negative feedback mechanism [99], so there is an inverse relationship between the amount of circulating platelets, and the amount of TPO that can reach the bone marrow to stimulate thrombopoiesis. In liver cirrhosis perhaps a decreased syntehesis of TPO could be implicated in the development of thrombocytopenia. Controversial findings regarding the role of each mechanism in thrombocytopenia of liver cirrhosis have been reported [142, 146, 160-161, 184] and no study has simultaneously evaluated the influence of the different mechanisms including portal hypertension and TPO production nor whether their influence could change in different stages of the disease..
Synthesis and Properties of Naphthobisbenzothiophene Diimides
Laterally extended naphthalene diimides composed of naphthobisbenzothiophene skeleton and two imide groups were synthesized, which exhibit interesting packing arrangements and optoelectrical properties
Synthesis and Properties of Naphthobisbenzothiophene Diimides
Laterally extended naphthalene diimides composed of naphthobisbenzothiophene skeleton and two imide groups were synthesized, which exhibit interesting packing arrangements and optoelectrical properties
Kinetics of Homoallylic/Homobenzylic Rearrangement Reactions under Combustion Conditions
Homoallylic/homobenzylic
radicals refer to typical radicals with
the radical site located at the β position from the vinyl/phenyl
group. These radicals are largely involved in combustion systems,
such as the pyrolysis or oxidation of alkenes, cycloalkanes, and aromatics.
The 1,2-vinyl/phenyl migration via two steps (cyclization/fission)
is a peculiar reaction type for the homoallylic/homobenzylic radicals,
entitled homoallylic/homobenzylic rearrangement, which has been studied
by theoretical calculations including the Hirshfeld atomic charge
analysis in the present work. With the help of rate constant calculations,
the competition between this reaction channel and other possible pathways
under combustion temperatures (500–2000 K) were evaluated.
Analogous 1,3- and 1,4-vinyl/phenyl migration reactions for similar
radicals with the radical sites located at the γ and δ
positions from the vinyl/phenyl group were also computed. The results
indicate that the 1,2-vinyl/phenyl migration is particularly important
for the kinetics of unimolecular reactions of homoallylic radicals
under 1500 K; nevertheless, it still has noticeable contribution at
higher temperature. For those radicals with the radical site at the
γ or δ positions, the respective 1,3- or 1,4-vinyl/phenyl
migration channel plays an insignificant role under combustion conditions
Conventional multiplex PCR.
<p>During conventional multiplex PCR with overlapping amplicons, four amplicons are produced. For each cycle, Amplicon 3 can be amplified from not only the original template, but also Amplicons 1, 2, and 4. Its growth overtakes the reaction and hinders the amplification of the target amplicons.</p
Tailorable Aqueous Dispersion of Single-Walled Carbon Nanotubes Using Tetrachloroperylene-Based Bolaamphiphiles via Noncovalent Modification
The
enhanced dispersing capability of these bolaamphiphiles can
be attributed to the large aromatic perylene core. The aqueous dispersion
efficiency of single-walled carbon nanotubes (SWCNTs) is investigated
by UV–vis absorption, fluorescence emission and Raman spectra,
scanning electron microscopy, transmission electron microscopy, and
atomic force microscopy. It is found that the tetrachloroperylene
backbone moieties could interact with SWCNT via synergistic π–π
and hydrophobic interactions, and the dispersing properties are closely
related to the hydrophilic part of bolaamphiles. This study not only
demonstrates tetrachloroperylene derivatives are able to stabilize
SWCNTs, but also provides the possibility to understand the structure–property
relationship between SWCNTs and tetrachloroperylene-based surfactants
Cyano-Substituted Perylene Diimides with Linearly Correlated LUMO Levels
A series of nonbay
region cyano-substituted tetrachloroÂperylene
diimides with tunable LUMO energy levels from −4.21 to −4.64
eV were developed. The excellent linear correlation between LUMO energy
levels and the number of cyano groups indicated that the LUMO energy
levels could be lowered effectively and predictably by incorporating
cyano groups
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