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Yang, Jun

Publications and source records attributed to Yang, Jun.

85 records · Page 5
All sourcesNASA NTRSDOE OSTI
DOE OSTI2014

Strigolactone-Regulated Proteins Revealed by iTRAQ-Based Quantitative Proteomics in Arabidopsis

Strigolactones (SLs) are a new class of plant hormones. In addition to acting as a key inhibitor of shoot branching, SLs stimulate seed germination of root parasitic plants and promote hyphal branching and root colonization of symbiotic arbuscular mycorrhizal fungi. They also regulate many other aspects of plant growth and development. At the transcription level, SL-regulated genes have been reported. However, nothing is known about the proteome regulated by this new class of plant hormones. Here, a quantitative proteomics approach using an isobaric chemical labeling reagent, iTRAQ, to identify the proteome regulated by SLs in Arabidopsis seedlings is presented. It was found SLs regulate the expression of about three dozens of proteins that have not been previously assigned to SL pathways. These findings provide a new tool to investigate the molecular mechanism of action of SLs.

proteomics↗
DOE OSTI2013

Magnetic properties and loss separation in iron-silicone-MnZn ferrite soft magnetic composites

This paper investigates the magnetic and structural properties of iron-based soft magnetic composites coated with silicone-MnZn ferrite hybrid. The organic silicone resin was added to improve the flexibility of the insulated iron powder and causes better adhesion between particles to increase the mechanical properties. Scanning electron microscopy and distribution maps show that the iron particle surface is covered with a thin layer of silicone-MnZn ferrite. Silicone-MnZn ferrite coated samples have higher permeability when compared with the non-magnetic silicone resin coated compacts. The real part of permeability increases by 34.18% when compared with the silicone resin coated samples at 20 kHz. In this work, a formula for calculating the total loss component by loss separation method is presented and finally the different parts of total losses are calculated. The results show that the eddy current loss coefficient is close to each other for the silicone-MnZn ferrite, silicone resin and MnZn ferrite coated samples (0.0078<k{sub 3}<0.008), but the hysteresis loss coefficient is lower for the silicone-MnZn ferrite coated sample (k{sub 2} =1.4058) in comparison with other samples.

36 MATERIALS SCIENCE↗
DOE OSTI2013

Effect of Fractionation in Stereotactic Body Radiation Therapy Using the Linear Quadratic Model

Purpose: To examine the fractionation effect of stereotactic body radiation therapy with a heterogeneous dose distribution. Methods: Derived from the linear quadratic formula with measurements from a hypothetical 2-cm radiosurgical tumor, the threshold percentage was defined as (α/β{sub tissue}/α/β{sub tumor}), the balance α/β ratio was defined as (prescription dose/tissue tolerance*α/β{sub tumor}), and the balance dose was defined as (tissue tolerance/threshold percentage). Results: With increasing fractions and equivalent peripheral dose to the target, the biological equivalent dose of “hot spots” in a target decreases. The relative biological equivalent doses of serial organs decrease only when the relative percentage of its dose to the prescription dose is above the threshold percentage. The volume of parallel organs at risk decreases only when the tumor's α/β ratio is above the balance α/β ratio and the prescription dose is lower than balance dose. Conclusions: The potential benefits of fractionation in stereotactic body radiation therapy depend on the complex interplay between the total dose, α/β ratios, and dose differences between the target and the surrounding normal tissues.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2013

The targeted inhibition of mitochondrial Hsp90 overcomes the apoptosis resistance conferred by Bcl-2 in Hep3B cells via necroptosis

Previous studies have reported that a Gamitrinib variant containing triphenylphosphonium (G-TPP) binds to mitochondrial Hsp90 and rapidly inhibits its activity, thus inducing the apoptotic pathway in the cells. Accordingly, G-TPP shows a potential as a promising drug for the treatment of cancer. A cell can die from different types of cell death such as apoptosis, necrosis, necroptosis, and autophagic cell death. In this study, we further investigated the mechanisms and modes of cell death in the G-TPP-treated Hep3B and U937 cell lines. We discovered that G-TPP kills the U937 cells through the apoptotic pathway and the overexpression of Bcl-2 significantly inhibits U937 cell death to G-TPP. We further discovered that G-TPP kills the Hep3B cells by activating necroptosis in combination with the partial activation of caspase-dependent apoptosis. Importantly, G-TPP overcomes the apoptosis resistance conferred by Bcl-2 in Hep3B cells via necroptosis. We also observed that G-TPP induces compensatory autophagy in the Hep3B cell line. We further found that whereas there is a Bcl-2-Beclin 1 interaction in response to G-TPP, silencing the beclin 1 gene failed to block LC3-II accumulation in the Hep3B cells, indicating that G-TPP triggers Beclin 1-independent protective autophagy in Hep3B cells. Taken together, these data reveal that G-TPP induces cell death through a combination of death pathways, including necroptosis and apoptosis, and overcomes the apoptosis resistance conferred by Bcl-2 in Hep3B cells via necroptosis. These findings are important for the therapeutic exploitation of necroptosis as an alternative cell death program to bypass the resistance to apoptosis. Highlights: ► G-TPP binds to mitochondrial Hsp90. ► G-TPP induces apoptosis in U937 human leukemia cancer cells. ► G-TPP induces combination of death pathways in Hep3B cell. ► G-TPP overcomes the resistance conferred by Bcl-2 in Hep3B cells via necroptosis. ► G-TPP triggers Beclin 1-independent protective autophagy in Hep3B cells.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2012

Tandem Polymer Solar Cells Featuring a Spectrally Matched Low-Bandgap Polymer

Tandem solar cells provide an effective way to harvest a broader spectrum of solar radiation by combining two or more solar cells with different absorption bands. However, for polymer solar cells, the performance of tandem devices lags behind single-layer solar cells mainly due to the lack of a suitable low-bandgap polymer. Here, we demonstrate highly efficient single and tandem polymer solar cells featuring a low-bandgap conjugated polymer (PBDTT-DPP: bandgap, {approx}1.44 eV). A single-layer device based on the polymer provides a power conversion efficiency of {approx}6%. When the polymer is applied to tandem solar cells, a power conversion efficiency of 8.62% is achieved, which is, to the best of our knowledge, the highest certified efficiency for a polymer solar cell to date.

14 SOLAR ENERGY↗
DOE OSTI2012

Synthesis of N1-tritylethane-1,1,2,2-d4-1,2-diamine: a novel mono-protected C-deuterated ethylenediamine synthon

A convenient and high-yield synthesis for N1-tritylethane-1,1,2,2-d4-1,2-diamine, a novel mono-protected ethylenediamine-C-d4, is reported. N1-tritylethane-1,1,2,2-d4-1,2-diamine was prepared in three steps from ethylene oxide-d4 in a combined yield in the range 68-76%. Also reported is a synthesis of ethylenediamine-C-d4 in two steps from 1,2-dibromoethane-d4 in a combined yield in the range 61-65%.

deuterated ethylenediamine↗
DOE OSTI2011

Spatial distribution of intra-molecular water and polymeric components in polyelectrolyte dendrimers revealed by small angle scattering investigations

An experimental scheme using contrast variation small angle neutron scattering technique (SANS), is developed to investigate the structural characteristics of amine-terminated poly(amidoamine) dendrimers (PAMAM) solutions. The focus is placed on understanding the dependence of intra-dendrimer water and polymer distribution on molecular protonation, which can be precisely adjusted by tuning the pH value of solution. Assuming the spherical symmetry in the spatial arrangement of the constituent component of dendrimer, and the atomic ratio of hydrogen-to-deuterium for the solvent residing within the cavities of dendrimer is identical to that for the solvent outside dendrimer, the intra-dendrimer water distribution along the radial direction can be determined based on the model of coherent scattering cross section developed in this work. Moreover, our result clearly reveals an outward relocation of the peripheral groups, as well as the enhanced intra-dendrimer hydration, upon increasing the molecular protonation and therefore allows the determination of segmental backfolding in a quantitative manner. The connection between these charge-induced structural changes and our recently observed progressively active segmental dynamics is also discussed.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2011

A method for preparing sodium acrylate-d3, a useful and stable precursor for deuterated acrylic monomers

A convenient and economical method for converting propiolic acid to sodium acrylate-d3 is described. Successive D/H exchange of the alkyne proton of sodium propiolate (prepared from propiolic acid) using D2O affords sodium propiolate-d having up to 99 atom% D. Sodium propiolate-d can be partially reduced to sodium acrylate-d3 with 90% conversion and 89% yield, using D2 and the Lindlar catalyst with control of reaction parameters to maximize conversion while minimizing over reduction.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2010

A facile synthesis of novel nanorod-assembling hollow nanowires of cadmium sulfide/DBTU nanocomposite

Novel nanorod-assembling hollow nanowires of cadmium sulfide/DBTU (N,N'-dibutylthiourea) nanocomposite were synthesized by reacting CdCl{sub 2} with in situ produced H{sub 2}S from reaction of butylamine and carbon disulfide at molar ratio 3:3 of CS{sub 2}:BuNH{sub 2} at 50 {sup o}C. This product was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SEAD), energy dispersive X-ray spectroscopy (EDAX), thermogravimetric (TG), Fourier transform infrared (FTIR) and UV-vis absorption spectra. A plausible mechanism that the extending DBTU molecules in solvent of CS{sub 2} induce the formation of CdS/DBTU nanorods by coordinating with the formed CdS particles, and construct these nanorods to hollow nanowires via molecular interactions is proposed and discussed on the basis of experimental results. Photoluminescence (PL) of CdS/DBTU nanocomposite exhibits increasing emission intensity largely.

36 MATERIALS SCIENCE↗
DOE OSTI2010

Multi-component hydrogen storage material

A reversible hydrogen storage composition having an empirical formula of: Li.sub.(x+z)N.sub.xMg.sub.yB.sub.zH.sub.w where 0.4.ltoreq.x.ltoreq.0.8; 0.2.ltoreq.y.ltoreq.0.6; 0<z.ltoreq.0.4, x+y+z=1 and "w" varies from 0 to 2x+2y+4z. This composition shows greater low temperature reversible hydrogen storage compared to binary systems such as MgH.sub.2--LiNH.sub.2.

Faheem, Syed A↗
DOE OSTI2010

Red Shell: Defining a High-Risk Zone of Normal Tissue Damage in Stereotactic Body Radiation Therapy

Purpose: To define a volume of tissue just outside of the clinical target volume (CTV) or planning target volume (PTV) in stereotactic body radiation therapy (SBRT) that receives doses appreciably above the tolerance level and in which other critical tissue structures must be avoided. Methods and Materials: We define the tissue between the borders of the CTV and PTV as the Inner Red Shell. The tissue surrounding the PTV that receives higher than the local tissue tolerance is defined as the Outer Red Shell. Contributing factors to the volume of the Red Shell include the prescription dose, dose gradient and PTV size, together with the type of tissue and its tolerance are discussed. An illustrative example and two clinical cases are reported. Results: The volume of Red Shell increases with higher prescription dose, slower dose fall-off, larger PTV volume, and higher tissue radiosensitivity. Avoidance of proximal critical serial organs may alter the volume and shape of the Red Shell after repeated, detailed treatment planning. Conclusion: Rather than defining tolerance and toxicity as simply a dose level received by the tissues, the volume of tissue receiving risk levels above tolerance can be quantified as the 'cost' of SBRT. This concept may be adopted in other techniques offering ablative and high-dose gradients. Further consideration should be given to collecting clinical data for refining the choice of constraint doses, especially in parts of the brain, lung, liver, and kidney.

62 RADIOLOGY AND NUCLEAR MEDICINE↗