2,511 research outputs found
ΔNp63α a key factor of epithelial differentiation controls the activity of YB-1 oncoprotein: potential implications in carcinogenesis
No full textMy thesis unveils a novel protein-protein association involving ΔNp63αand YB-1 and a mechanism through which a factor essential for epithelial development and differentiation can control the activity of an oncoprotein
YB-1 modulates the drug resistance of glioma cells by activation of MDM2/p53 pathway
No full textHui Tong,1,* Kai Zhao,2,* Jingyu Zhang,3 Jinxin Zhu,4 Jianqi Xiao2 1Department of Neurosurgery, Linyi Central Hospital, Linyi, Shandong 276400, People’s Republic of China; 2Department of Neurosurgery, The First Hospital of Qiqihar City, Qiqihar, Heilongjiang 161005, People’s Republic of China; 3Department of Internal Medicine, Jiangpu District Health Center of Huai’an, Huai’an, Jiangsu, 223001, People’s Republic of China; 4Department of Neurosurgery, Lianshui County People’s Hospital, Huai’an, Jiangsu 223400, People’s Republic of China *These authors contributed equally to this work Background: Y-box-binding protein-1 (YB-1) is aberrantly expressed in a variety of cancers. However, the biological functional role of YB-1 in glioma is not yet clear. Methods: The expression of MDM2 and YB-1 was analyzed by real time PCR. Overexpression and knockdown of YB-1 in glioma cells were created by transfection of pcDNA-YB-1 and siRNA against YB-1, respectively. Cell viability was performed by CCK8 assay.Results: Our findings showed that glioma tissues had higher expressions of YB-1 than that in cancer-free tissues in 54 glioma patients, which were also positively correlated with Murine MDM2 expression. Overexpression of YB-1 or MDM2 renders a drug resistance feature in glioma cell exposed to temozolomide (TMZ), by directly targeting p53. Genetic or chemical inhibition of MDM2 significantly blocked YB-1-modulated response of glioma cells to TMZ. Moreover, inhibition of YB-1 or MDM2 reduced glioma cells metastasis and mortality in mice. Conclusion: YB-1 facilitates the resistance of glioma cells to TMZ by direct activation of MDM2/p53 signaling and represents a promising molecular target for glioma treatment. Keywords: glioma, p53, Murine double minute 2, Y-box binding protein-1, drug resistance, temozolomide 
Yb<sup>3+</sup>-Yb<sup>3+</sup> cooperative upconversion in oxyfluoride glass and glass ceramics
No full textYb
3+-doped oxyfluoride glasses and glass ceramics containing KZnF
3 nanocrystals were obtained by melt-quenching. Under excitation of a 980 nm laser, a strong blue emission from Yb
3+-Yb
3+ cooperative upconversion was observed in the glass sample, which increased by five times in glass ceramics after heat treatment for 20 h. The photoluminescence mechanism and sample properties were investigated by X-ray diffraction, transmission electron microscopy, fluorescent lifetime, absorption and emission spectra. The size of KZnF
3 nanocrystals is in the range 5 nm–20 nm, making the glass ceramic samples highly transparent. The STEM-EDS measurements indicate that the distribution of Yb is consistent with that of the KZnF
3 nanocrystals. Fluroide phase provides a low-phonon-energy environment for Yb
3+-Yb
3+ ion pairs, which facilitates an intense fluorescent blue emission in the KZnF
3 crystal lattice. Both theoretical and experimental results demonstrate that Yb
3+-doped oxyfluoride glasses and glass ceramics containing KZnF
3 nanocrystals are promising materials for blue upconversion emission.
</p
Towards the tumble resistant microlight
No full textThe tumble mode is a pitching departure from controlled flight which leads to a pitch autorotation that is generally unrecoverable – resulting in vertical ground impact, usually preceded by in-flight breakup (the mechanism for which, surprisingly, can sometimes prevent loss of life). This was identified in work led by the British Microlight Aircraft Association beginning in 1997 as a response to a number of fatal accidents in Rogallo winged microlight aeroplanes, although the tumble is also known to occur to hang-gliders. This paper explains how this class of aeroplane is controlled, and how it has been found that they can enter the tumble mode. The mechanism by which the tumble can be entered is described. This has led to work showing how flight testing can be used to establish and demonstrate resistance to tumble entry – particularly important with increasing number of very high performance flexwings. These flight tests will be explained, together with the significance of the results. Recent accident investigation work has also shown a new mechanism of tumble entry, through partial failure of the A-frame structure and the pitch-trimmer mechanism. Also described is a possible relevance to well known historical accidents to flying wing aeroplanes– specifically the YB-49 and dH-108, and discovered data on the characteristics of the BKB-1flying wing glider; are also described
Calculation of surface tension using CALPHAD software as a Zero Phase Fraction line of ""surface"" phase
No full textA new approach for calculation of surface tension of solutions is presented. Based on the proposal of Butler (Proc. R. Soc. Lond. A: Math. Phys. Eng. Sci. 135 (1932) 348 [3]), a surface phase was assumed to be in equilibrium with a corresponding bulk phase. Following the proposal of Pajarre et al. (Calphad 30 (2006) 196 [71), a surface area element (X) was introduced, only in the surface phase. The surface tension can be obtained by Constrained Gibbs Energy Minimization (CGEM) under a constraint of constant surface. The equilibrium chemical potential of the surface element, X, was interpreted to be proportional to the surface tension. According to the present author (Calphad 50 (2015) 23 [9]), the surface tension calculation by the CGEM can be interpreted as if the bulk phase and the surface phase are in equilibrium with each other, and the chemical potential of the area element is obtained as a result of the equilibrium. It was shown that a geometrical relationship among the molar Gibbs energies of the bulk phase and the surface phase, the surface tension, and the surface concentration is found. In the present study, further improvement was made in such a way that the chemical potential of the area element can be simply obtained by combining the CGEM with Zero Phase Fraction (ZPF) line in Type II phase diagram, where the chemical potential of the area element is used as an axis variable. Such phase diagram can be easily calculated using conventional CALPHAD softwares. The proposed approach was validated for a number of binary and ternary systems. (C) 2015 Elsevier Ltd. All rights reserved.1122sciescopu
KW-level low photodarkening Yb/Ce codoped aluminosilicate fiber fabricated by the chelate gas phase deposition technique
No full text
A Yb/Ce codoped aluminosilicate fiber was successfully fabricated by the chelate gas phase deposition technique. Using the homemade fiber as the amplifier stage in a master oscillator power amplifier configuration laser setup, a near single mode laser output (M-2 = 1.55) with an output power of 1026 W and slope efficiency of 84.8% is obtained. In the 100 hour photodarkening experiment, the entire reduced power is less than 14 W, and the ratio, compared to the initial 1026 W output power, is less than 1.4%. The investigation of optical properties indicates that Yb/Ce codoped aluminosilicate fiber fabricated by the chelate gas phase deposition technique shows homogenous distribution, appropriate absorption coefficient, low background attenuation, high optical-to-optical efficiency and a rather low photodarkening loss, making it a promising candidate as an active fiber for a reliable and efficient fiber laser in high-power applications. (C) 2016 Optical Society of America</p
Near-IR Luminescent Yb-III Coordination Polymers Composed of Pyrene Derivatives for Thermostable Oxygen Sensors
No full textThis work synthesized oxygen sensitive and near infrared (NIR) luminescent Yb(III) coordination polymers incorporating ligands based on pyrene derivatives: Yb(III)-TBAPy and Yb(III)-TIAPy (TBAPy: 1,3,6,8-tetrskis(p-benzoate)pyrene, TIAPy: 1,3,6,8-tetrakis(3,5-isophtalic acid)pyrene). The coordination structures of these materials were characterized using electrospray ionization mass spectrometry, X-ray diffraction and thermogravimetric analysis, while the porous structure of the Yb(III)-TIAPy was evaluated based on its adsorption isotherm. The NIR luminescence properties of the Yb(III)-TBAPy and Yb(III)-TIAPy were examined by acquiring emission spectra and determining emission lifetimes under air, argon and vacuum. The Yb(III)-TIAPy exhibited high thermal stability (with a decomposition temperature of 400 °C), intense luminescence (with an emission quantum yield under argon of 6.6%) and effective oxygen-sensing characteristics. These results suggest that NIR luminescent Yb(III) coordination polymers made using pyrene derivatives could have applications in novel thermo-stable oxygen sensors
Zircon U-Pb age, element and C-O isotope geochemistry of post-collisional mafic-ultramafic rocks from the Dabie orogen in east-central China
No full textAchieving aerospace standard porosity levels when welding thin and thick-section aluminium using fibre-delivered lasers : executive summary
No full textEnvironmental and commercial pressures have forced the aerospace industry to look at
alternatives to riveting for the manufacture of aluminium aircraft structures. This resulted, at
the end of last century, in an extensive study by Airbus into the possiblities of using CO2
lasers, which led to the process being implemented for a (small) number of stringer-to-skin
fuselage panels in the newer Airbus models. Since this initial commercial success, new laser
sources have become available that are more suitable for the welding of aluminium than CO2
lasers, in the form of Nd: YAG and Yb-fibre lasers. Both produce a wavelength that is
absorbed more efficiently by aluminium alloys than the CO2 laser wavelength, resulting in an
improved keyhole stability, as demonstrated in the late nineties for Nd: YAG lasers. In addition,
Yb-fibre lasers have become available at output powers higher than available for Nd: YAG
lasers, allowing thicker sections of aluminium to be welded in a single pass. However, despite
their claimed advantages, no efforts were made to demonstrate the potential of these lasers
for (aluminium) aircraft manufacture. For this reason, the author initiated a series of studies in
2001, with the overall aim to develop procedures to laser weld both thin (3.2mm) and thicksection
(12.7mm) aerospace aluminium alloys using these fibre-delivered lasers to a weld
quality, in particular related to weld metal porosity, suitable for aerospace service. The focus
in this research was on weld metal porosity, because this is a particular problem when laser
welding aluminium, either in the form of fine (hydrogen) porosity or larger porosity associated
with an unstable keyhole behaviour. The benchmark weld metal porosity for this study was
obtained from the stringent weld quality classes defined in BS EN 13919-2 and AWS D17.1.
The approach to this research was in three parts, with work in the first aimed at demonstrating
that a 3kW Nd: YAG laser was capable of producing low-porosity welds in 3.2mm thickness
2024 aluminium alloy, and thus can be considered for replacing the CO2 laser currently used
for the stringer-to-skin fuselage application. Prior to the final part of the research, in which a
7kW Yb-fibre laser was used to demonstrate that these benchmark porosity levels could also
be achieved in thicker section (aerospace-grade) aluminium, a comparison study was carried
out to quantify the difference in welding performance between the Nd: YAG and the Yb-fibre
laser. At an output power of 4kW focused in a 0.4mm diameter spot, the Yb-fibre laser was
capable of a 30% higher welding speeds in 4mm (5083) aluminium alloy, or a 20% increase in
depth of penetration for welding speeds between 1 and 15m/min, compared with the Nd: YAG
laser. This improvement in welding performance, together with an output power of 7W,
produced full penetration in 12.7mm thickness (aerospace-grade) AI-Zn-Mg-Cu aluminium
alloy using the Yb-fibre laser autogenously, or in a hybrid configuration with a MIG arc. Both
the autogenous laser and hybrid laser-MIG process were capable of producing welds with a
weld metal porosity in line with the BS EN 13919-2 and AWS D17.1 benchmark conditions, at
welding speeds of 0.55 and 0.75m/min, respectively. At these production rates, the 248
metres of stringer incorporated in a typical aluminium wing structure can be welded in 7.5 and
5.5 hours, in case of autogenous laser and hybrid laser-MIG, respectively, compared with
37.6 hours currently needed for the riveting process
Diode-pumped passively Q-switched Yb : YAG microchip laser with a GaAs as saturable absorber
No full textA passively Q-switched Yb: YAG microchip laser has been constructed by using a doped GaAs as the saturable absorber as well as the output coupler. At 13.5 W of pump power the device produces high-quality 3.4 muJ 52 ns pulses at 1030nm with a pulse repetition rate of 7.8kHz in a TEM00-mode
- …
