Anti-apoptotic effect of quercetin: Intervention in the JNK- and ERK-mediated apoptotic pathways.
Bioflavonoid quercetin inhibits hydrogen peroxide (H2O2)-induced apoptosis via intervention in the ...activator protein 1 (AP-1)-mediated apoptotic pathway. In this report, we investigated molecular events involved in the anti-apoptotic effect of quercetin, focusing especially on its effects on the family of mitogen-activated protein (MAP) kinases.
Cultured mesangial cells were exposed to H2O2, and activation of c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinases (ERKs), and p38 MAP kinase was evaluated in the presence or absence of quercetin. Using pharmacological and genetic inhibitors, the roles for individual MAP kinases in H2O2-induced apoptosis were examined. Involvement of ERKs in the induction and activation of AP-1 was also investigated using Northern blot analysis and a reporter assay.
Mesangial cells exposed to H2O2 exhibited rapid phosphorylation of JNK, ERKs, and p38 MAP kinase. Quercetin abrogated the activation of all three MAP kinases in response to H2O2. Pretreatment with MAP kinase kinase inhibitor PD098059 or JNK-c-Jun/AP-1 inhibitor curcumin attenuated the H2O2-induced apoptosis. In contrast, the p38 MAP kinase inhibitor SB203580 did not improve the cell survival. Consistently, transfection with dominant-negative mutants of ERK1 and ERK2 or a dominant-negative mutant of JNK inhibited H2O2-induced apoptosis. Transfection with a dominant-negative p38 MAP kinase did not attenuate the apoptotic process. Inhibition of ERKs by PD098059 suppressed induction of c-fos without affecting early induction of c-jun, leading to attenuated activation of AP-1 in response to H2O2.
These results suggested that (1) activation of JNK and ERKs, but not p38 kinase, is required for the H2O2-induced apoptosis; and (2) suppression of the JNK-c-Jun/AP-1 pathway and the ERK-c-Fos/AP-1 pathway is involved in the anti-apoptotic effect of quercetin.
Semiconducting epi-Si1−xGex alloys have promising features as solar cell materials and may be equally important for some other semiconductor device applications. Variation of the germanium ...compositional, x in epi-Si1−xGex, makes it possible to control the bandgap between 1.12 eV and 0.68 eV for application in bottom solar cells. A low proportion of Ge in SiGe alloy can be used for photovoltaic application in a bottom cell to complete the four-terminal tandem structure with wide bandgap materials. In this research, we aimed to use a low proportion of Ge-about 10%-in strained or relaxed c-Si1−xGex/c-Si heterojunctions (HETs), with or without insertion of a Si buffer layer grown by molecular beam epitaxy, to investigate the influence of the relaxed or strained SiGe active layer on the performance of HET solar cells grown using the plasma enhanced chemical vapor deposition system. Thanks to the c-Si buffer layer at the hetero-interface, the efficiency of these SiGe based HET solar cells was improved from 2.3% to 3.5% (fully strained and with buffer layer). The Jsc was improved, from 8 mA cm−2 to 15.46 mA cm−2, which might be supported by strained c-Si buffer layer at the hetero-interface, by improving the crystalline quality.
“Stereo Compton cameras” for the 3-D localization of radioisotopes Takeuchi, K.; Kataoka, J.; Nishiyama, T. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2014, Letnik:
765
Journal Article
Recenzirano
The Compton camera is a viable and convenient tool used to visualize the distribution of radioactive isotopes that emit gamma rays. After the nuclear disaster in Fukushima in 2011, there is a ...particularly urgent need to develop “gamma cameras”, which can visualize the distribution of such radioisotopes. In response, we propose a portable Compton camera, which comprises 3-D position-sensitive GAGG scintillators coupled with thin monolithic MPPC arrays. The pulse-height ratio of two MPPC-arrays allocated at both ends of the scintillator block determines the depth of interaction (DOI), which dramatically improves the position resolution of the scintillation detectors. We report on the detailed optimization of the detector design, based on Geant4 simulation. The results indicate that detection efficiency reaches up to 0.54%, or more than 10 times that of other cameras being tested in Fukushima, along with a moderate angular resolution of 8.1° (FWHM). By applying the triangular surveying method, we also propose a new concept for the stereo measurement of gamma rays by using two Compton cameras, thus enabling the 3-D positional measurement of radioactive isotopes for the first time. From one point source simulation data, we ensured that the source position and the distance to the same could be determined typically to within 2 meters׳ accuracy and we also confirmed that more than two sources are clearly separated by the event selection from two point sources of simulation data.
•A scintillator-based Compton camera is being optimized using Geant4 simulations.•Both high efficiency and moderate angular resolution can be achieved simultaneously.•We ensured a new method of sensing the 3-D position of a source through simulations.•The source position can be determined typically within 2 meters׳ accuracy.•More than two sources can be visualized individually via a simple event selection.
We have used the relativistic multi-reference Moller-Plesset perturbation theory to calculate the energy levels of Fe XVI, including those of the autoionizing levels with a hole state in the L shell. ...Comparison of the resulting L-shell transition wavelengths with those from recent laboratory measurements shows remarkable agreement, i.e., agreement within the experimental uncertainties. Our calculation allows us to predict the wavelength of the second strongest 2p-3d Fe XVI line, which has not yet been directly observed in the laboratory, to be 15.266 Angstrom. This wavelength is within 0.0042 Angstrom of the strong Fe XVII line commonly labeled 3D. Relying on the high accuracy of our calculations, we have reassigned two previously identified lines and predict a different location than previously thought for the strongest Fe XVI magnetic quadrupole transition. Inspection of the spectra of Capella recorded with the transmission grating spectrometers on the Chandra X-ray Observatory yields features corresponding to the predicted location of the innershell excited Fe XVI lines. These features have not been identified before. Our analysis shows that these features are most likely from Fe XVI.
The tumor suppressor Fbxw7 (also known as Sel-10, hCdc4, hAgo, or Fbw7) is an F-box protein that functions as the substrate-recognition subunit of an SCF ubiquitin ligase complex and targets a group ...of oncoproteins for degradation. We now show that Fbxw7 regulates the proliferation and differentiation of keratinocytes by mediating the degradation of c-Myc and Notch proteins. Fbxw7-deficient keratinocytes showed an increased proliferative capacity that was dependent on the accumulation of c-Myc but not on that of Notch. Fbxw7 deficiency also resulted in the premature differentiation of keratinocytes in a manner dependent on both c-Myc and Notch. Although Fbxw7-deficient keratinocytes proliferated excessively in vitro, loss of Fbxw7 did not predispose keratinocytes to the formation of squamous cell carcinoma in vivo induced by the expression of oncogenic Ras, possibly because the stem cell population of keratinocytes becomes exhausted as a result of enhanced Notch activity. Indeed, suppression of Notch signaling by additional ablation of RBP-J in Fbxw7-deficient keratinocytes conferred a more aggressive tumorigenic capacity. Collectively, these results indicate that Fbxw7 controls the proliferation and differentiation of keratinocytes, and that it exerts both inhibitory and stimulatory actions in skin carcinogenesis by counteracting the proliferation-promoting effect of c-Myc and the tumor-suppressive effect of Notch, respectively.
The discovery of a high-mobility two-dimensional electron gas (2DEG) in wurtzite ZnO/Zn(Mg)O heterostructures is promising for applications due to the high mobility of the carriers. In this paper, we ...study the formation and properties of the 2DEG at ZnO/Zn(Mg)O interfaces using first-principles calculations based on hybrid density functional theory. The 2DEG arises from the polarization discontinuity at the interface between the two materials. The uncompensated bound charge at the interface gives rise to an electric field in the bulk of ZnO which confines free carriers close to the interface. We find that the type of the confined carriers is determined by the interface termination, while the amount of charge and the confinement width could be controlled by the Mg doping and the device dimensions.
To assess the effect of multiple factors on quality of life (QOL) in osteoporosis, relationships between the QOL and possible spinal factors were analyzed in 174 postmenopausal women with ...osteoporosis. Back extensor strength and lumbar spinal mobility were the most important factors for QOL in these patients.
Quality of life (QOL) in patients with osteoporosis and vertebral fractures is impaired by the decline of total spinal mobility, although it is not clear to what extent. This study aimed to assess the effect of multiple factors on QOL in patients with osteoporosis.
QOL of 174 postmenopausal women with osteoporosis (mean, 68 years old) was evaluated using the Japanese Osteoporosis QOL Questionnaire (JOQOL). Correlations between the JOQOL score, bone mineral density (BMD) of the lumbar spine/proximal femur/whole body, the kyphosis angle and mobility of thoracic and lumbar spine, the number of vertebral fractures, grip strengths of dominant and non-dominant hands, and isometric back extensor strength (BES) were analyzed.
JOQOL showed significant correlation (p < 0.05) with age (r = -0.303), BES (r = 0.455), dominant and non-dominant grip strengths (r = 0.273 and r = 0.255, respectively), number of vertebral fractures (r = -0.282), BMDs of proximal femur and whole body (r = 0.200 and r = 0.157, respectively), lumbar kyphosis angle (r = -0.296), and lumbar spinal mobility (r = 0.345). Multiple regression analysis revealed that the BES and lumbar spinal mobility were the significant contributors to the JOQOL (p < 0.05).
BES and lumbar spinal mobility are the important factors for QOL in patients with postmenopausal osteoporosis.
Infection with
and
may lead to diffuse cutaneous leishmaniasis. The cure is exceptional, especially for the strange case of this lady. Case report: The patient acquired the disease in childhood and ...remained with lesions for over 30 years, albeit several treatments. She worsened after a pregnancy, developing disseminated lesions. Miltefosine with amphotericin B and pentamidine resulted in remission. Lesions reappeared after one year, accompanied by intra-nasal infiltration of the disease. The nasal spraying of a single ampoule of pentavalent antimoniate resulted in the sustained disappearance of the nasal symptoms and all the cutaneous lesions. After over eight years, she remains disease-free, albeit under renal replacement therapy. The high nasal mucosal antimonial concentration may explain the long-lasting cure via new MHC class I epitope-specific CD8+ cell clones against
present in the nasal mucosa.
We have developed a millimeter-wave electron-spin-resonance (ESR) measurement system using a
3
He-
4
He dilution refrigerator for the ultralow-temperature range below 1 K. The currently available ...frequency range is 125–130 GHz. This system is based on a Fabry-Pérot-type resonator (FPR) that is composed of two mirrors. The frequency can be changed by adjusting the distance between the mirrors using a piezoelectric actuator installed at the bottom of the resonator. A homodyne detection system with an InSb detector is built into the low-temperature section of the
3
He-
4
He dilution refrigerator; this system provides high sensitivity. Using this system, we performed ESR measurements on a Heisenberg quantum-spin chain—copper pyrazine dinitrate, Cu(C
4
H
4
N
2
)(NO
3
)
2
—over the temperature range from 6.6 down to 0.25 K. The ESR lines change continuously with decreasing temperature. Our results suggest that the ESR spectrum of copper pyrazine dinitrate may be useful as a temperature sensor for the very low-temperature range.
We have analyzed 280 ks of co-added observations performed with Chandra's Low Energy Transmission Grating Spectrometer using theoretical spectra of Fe VII through Fe XVII. The model spectral data ...were produced by combining collisional excitation data generated with the Flexible Atomic Code and transition energies generated with a relativistic code based on the multi-reference Moller-Plesset perturbation theory. The spectroscopic accuracy of the theoretical Fe IX wavelengths was ascertained in a comparison with existing laboratory measurements. We find several new Fe IX lines in the 100-140 Angstrom region and confirm two previous identifications. We also have identified a new line from Fe X near 111 Angstrom; several weak features near 102 Angstrom may also be ascribed to Fe X. A line near 100.5 Angstrom is identified as originating from Fe XI; a neighboring feature near 101 Angstrom may also be from Fe XI. A cluster of three weak lines between 117 and 118 Angstrom may be ascribed to Fe XII. Two lines near 104 and 106 Angstrom, respectively, have been assigned to Fe XIII. In addition, we confirmed the presence of two out of four Fe VIII lines that were thought to exist in the spectrum. These two lines are located near 131 Angstrom. The Fe IX emission is weakly sensitive to the assumed electron density, while the Fe XIII is strongly dependent on density. We find that a density between 10 super(9) and 10 super(10) cm super(-3) provides the best fit to the Procyon spectrum. We note that several of the new identifications have come at the expense of prior assignments to magnesium or calcium lines, removing evidence for the presence of these elements in this spectral region. No evidence for Fe XVII, Fe XIX, or Fe XX was found.
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