42 research outputs found
Polyploidization of Hepatocytes: Insights into the Pathogenesis of Liver Diseases
Polyploidization is a process by which cells are induced to possess more than two sets of chromosomes. Although polyploidization is not frequent in mammals, it is closely associated with development and differentiation of specific tissues and organs. The liver is one of the mammalian organs that displays ploidy dynamics in physiological homeostasis during its development. The ratio of polyploid hepatocytes increases significantly in response to hepatic injury from aging, viral infection, iron overload, surgical resection, or metabolic overload, such as that from non-alcoholic fatty liver diseases (NAFLDs). One of the unique features of NAFLD is the marked heterogeneity of hepatocyte nuclear size, which is strongly associated with an adverse liver-related outcome, such as hepatocellular carcinoma, liver transplantation, and liver-related death. Thus, hepatic polyploidization has been suggested as a potential driver in the progression of NAFLDs that are involved in the control of the multiple pathogenicity of the diseases. However, the importance of polyploidy in diverse pathophysiological contexts remains elusive. Recently, several studies reported successful improvement of symptoms of NAFLDs by reducing pathological polyploidy or by controlling cell cycle progression in animal models, suggesting that better understanding the mechanisms of pathological hepatic polyploidy may provide insights into the treatment of hepatic disorders.N
Synthesis, optical properties, and energy transfer of Ce 3+/Tb3+ co-doped MyGdFx (M = Li, Na, K)
Through a solid-state reaction method, the Ce3+/Tb3+ co-doped MyGdFx (M = Li, Na, K; x = 3, 4, 6; y = 0, 1, 3) system samples have been synthesized by controlling the annealing temperatures and the ratios of raw materials. The samples were characterized by X-ray diffraction (XRD) patterns, photoluminescence (PL) excitation and emission spectra as well as luminescent dynamic decay curves. The experimental results suggest that the LiF is more difficult to react with the prepared material compared that of NaF or KF under similar reaction conditions. The samples crystallized in different crystalline phases. The energy transfer from Ce 3+ to Tb3+ or Ce3+ to Gd3+ to Tb3+ has been observed in all the samples. The Ce3+ and Tb3+ present different optical properties for they are sensitive to the local environment. In addition, the deduced lifetime of Tb3+ 5D4 → 7F5 transition decreases in the same system samples with the annealing temperature increasing. The deduced lifetime of Tb3+ 5D4 → 7F5 also decreases with the increase of the KF concentration in the KF system samples. ? 2014 Elsevier B.V. All rights reserved
Inhibitory Effects of Resveratrol and Piceid against Pathogens of Rice Plant, and Disease Resistance Assay of Transgenic Rice Plant Transformed with Stilbene Synthase Gene
Resvestrol has been known to inhibit bacterial and fungal growth in vitro, and can be accumulated in plant to
concentrations necessary to inhibit microbial pathogens. Hence, stilbene synthase gene has been used to
transform to synthesize resveratrol in heterologous plant species to enhance resistance against pathogens. In
the present study, we investigated the antimicrobial activities of resveratrol and piceid to bacterial and fungal
pathogens, which causing severe damages to rice plants. In addition, disease resistance was compared
between transgenic rice varieties, Iksan 515 and Iksan 526 transformed with stlibene synthase gene and nontransgenic
rice varieties, Dongjin and Nampyeong. Minimum inhibitory concentration of resveratrol for
Burkolderia glumae was 437.5 μM, and the mycelial growth of Biplaris oryzae was slightly inhibited at
concentration of 10 μM. However, other bacterial and fungal pathogens are not inhibited by resveratrol and
piceid. The expression of the stilbene synthase gene in Iksan 515 and Iksan 526 did not significantly enhanced
resistance against bacterial grain rot, bacterial leaf blight, sheath blight, and leaf blight. This study is the first
report on the effect of resveratrol and piceid against pathogens of rice plant, and changes of disease resistance
of transgenic rice plants transformed with stilbene synthase gene
Wide-Band Excited Y<sub>6</sub>(WMo)<sub>0.5</sub>O<sub>12</sub>:Eu Red Phosphor for White Light Emitting Diode: Structure Evolution, Photoluminescence Properties, and Energy Transfer Mechanisms Involved
Y<sub>6</sub>(WMo)<sub>0.5</sub>O<sub>12</sub> activated with Eu<sup>3+</sup> ions was investigated as
a red-emitting conversion phosphor
for white light emitting diodes (WLEDs). The phosphors were synthesized
by calcining a citrate-complexation precursor at different temperatures.
The photoluminescence properties of the phosphors and the energy transfer
mechanisms involved were studied as a function of structure evolution.
It was found that the host lattices were crystallized in a cubic or
a hexagonal phase depending on the synthesis conditions. Although
all the phosphors showed intensive red emission under an excitation
of near-UV or blue light due to energy transfer from the host lattices
to Eu<sup>3+</sup> ions, the photoluminescence spectra and temporal
decay features were found to vary significantly with the structure
and crystallinity of the host lattice. The mechanisms of the energy
transfer from the host lattices to Eu<sup>3+</sup> ions and energy
quenching among Eu<sup>3+</sup> ions were discussed on the basis of
structure evolution of the host lattice. Phosphors calcined at 800
and 1300 °C were suggested to be promising candidates for blue
and near-UV light excited WLEDs, respectively