Ternary Phase Diagram-Facilitated Rapid Screening of Double Perovskites As Electrocatalysts for the Oxygen Evolution Reaction

Sun, Hainan,Hu, Zhiwei,Xu, Xiaomin,He, Juan,Dai, Jie,Lin, Hong-Ji,Chan, Ting-Shan,Chen, Chien-Te,Tjeng, Liu Hao,Zhou, Wei,Shao, Zongping American Chemical Society 2019 Chemistry of materials Vol.31 No.15

<P>The development of cost-effective, non-noble metal electrocatalysts for the oxygen evolution reaction (OER) is of paramount importance for sustainable technologies. Efficient screening strategies for electrocatalysts can greatly increase the commercialization speed of these advanced technologies. Here, ternary phase diagrams with large-scale tuning and designated-scale tuning strategies are applied for the first time to provide a new method for screening perovskite oxide-based electrocatalysts for OERs. Specifically, the family of double perovskites (Sr<SUB>2</SUB>Fe<SUB>1.5-<I>x</I>-<I>y</I></SUB>Co<SUB><I>x</I></SUB>Ni<SUB><I>y</I></SUB>Mo<SUB>0.5</SUB>O<SUB>6−δ</SUB>, 0 ≤ <I>x</I>, <I>y</I> ≤ 1.5) was utilized to understand the role of transition metals in perovskite oxides. Ternary phase diagrams can facilitate a rapid screening process, provide a straightforward relationship between phase structures and catalytic activities, and help to confirm the effects of various combinations of transition metals on the OER activity. The Fe-Co system (Sr<SUB>2</SUB>Fe<SUB>1.5-<I>x</I></SUB>Co<SUB><I>x</I></SUB>Mo<SUB>0.5</SUB>O<SUB>6−δ</SUB>) improves the catalytic activities, as demonstrated by the reduced Tafel slope and enhanced stability, while the Fe-Ni system (Sr<SUB>2</SUB>Fe<SUB>1.5-<I>y</I></SUB>Ni<SUB><I>y</I></SUB>Mo<SUB>0.5</SUB>O<SUB>6−δ</SUB>) improves the surface kinetic properties of the OER, as demonstrated by its reduced overpotential. Significantly, the Co, Ni, and Fe ternary phase systems can serve as the synergistic coactive sites (Sr<SUB>2</SUB>Fe<SUB>1.5-<I>x</I>-<I>y</I></SUB>Co<SUB><I>x</I></SUB>Ni<SUB><I>y</I></SUB>Mo<SUB>0.5</SUB>O<SUB>6−δ</SUB>) to catalyze the OER, resulting in an improved overall OER performance. This systematic study not only demonstrates a new strategy to allow the rapid screening of double perovskite OER catalysts based on large-scale tuning and designated-scale tuning strategies but, more importantly, also provides an insightful understanding of the use of multitransition metal-based double perovskites for catalysis of the OER.</P> [FIG OMISSION]</BR>

SKP2 Contributes to AKT Activation by Ubiquitination Degradation of PHLPP1, Impedes Autophagy, and Facilitates the Survival of Thyroid Carcinoma

Chongwen Xu,Yuan Shao,Wanli Ren,Hao Dai,Fangli Yang,Xiang Li,Shaoqiang Zhang,Junsong Liu,Xiaobao Yao,Qian Zhao,Xin Sun,Zhiwei Zheng 한국분자세포생물학회 2023 Molecules and cells Vol.46 No.6

Papillary thyroid carcinoma (PTC) is the most common subtype of thyroid carcinoma. Despite a good prognosis, approximately a quarter of PTC patients are likely to relapse. Previous reports suggest an association between S-phase kinase-associated protein 2 (SKP2) and the prognosis of thyroid cancer. SKP1 is related to apoptosis of PTC cells; however, its role in PTC remains largely elusive. This study aimed to understand the expression and molecular mechanism of SKP2 in PTC. SKP2 expression was upregulated in PTC tissues and closely associated with clinical diagnosis. In vitro and in vivo knockdown of SKP2 expression in PTC cells suppressed cell growth and proliferation and induced apoptosis. SKP2 depletion promoted cell autophagy under glucose deprivation. SKP2 interacted with PH domain leucine-rich repeat protein phosphatase-1 (PHLPP1), triggering its degradation by ubiquitination. Furthermore, SKP2 activates the AKT-related pathways via PHLPP1, which leads to the cytoplasmic translocation of SKP2, indicating a reciprocal regulation between SKP2 and AKT. In conclusion, the upregulation of SKP2 leads to PTC proliferation and survival, and the regulatory network among SKP2, PHLPP1, and AKT provides novel insight into the molecular basis of SKP2 in tumor progression.

Boosting the oxygen evolution reaction activity of a perovskite through introducing multi-element synergy and building an ordered structure

Sun, Hainan,Xu, Xiaomin,Hu, Zhiwei,Tjeng, Liu Hao,Zhao, Jie,Zhang, Qin,Lin, Hong-Ji,Chen, Chien-Te,Chan, Ting-Shan,Zhou, Wei,Shao, Zongping The Royal Society of Chemistry 2019 Journal of Materials Chemistry A Vol.7 No.16

<P>If different active sites in a catalyst have optimal binding to different reaction intermediates and short reaction paths among them, they may work cooperatively to enhance the oxygen evolution reaction (OER) activity. Based on this design principle, in this study, we start with a B-site ordered double perovskite Sr2FeMoO6−δ with poor OER activity as the host material to fulfill the requirement of a short pathway, and then, replace Mo with Ni and Fe with Co to optimize the synergistic interplay of the multi-active sites. Replacing Mo with Ni indeed dramatically enhances the OER activity and structural/operating stability. Further improvement in OER performance is realized by partial substitution of Fe with Co, leading to the development of a material with the nominal composition of Sr2Fe0.8Co0.2Mo0.65Ni0.35O6−δ, which outperforms the noble metal oxide IrO2 and is better than most of the electrocatalysts developed based on a single descriptor, such as Ba0.5Sr0.5Co0.8Fe0.2O3−δ (eg occupancy close to unity), PrBaCo2O5+δ (O 2p-band center relative to the Fermi level), and La0.5Sr0.5CoO3−δ (charge-transfer energy) in many aspects. As a universal method, combined structural and compositional tuning to create a cooperative effect among different active sites for intermediate adsorption and reaction in an ordered structure may provide a new way for the design of superior electrocatalysts for various applications.</P>

Hexadecanoic Acid from Buzhong Yiqi Decoction Induced Proliferation of Bone Marrow Mesenchymal Stem Cells

Dong-Feng Chen,Xican Li,Zhiwei Xu,Xiaobing Liu,Shao-Hui Du,Hui Li,Jian-Hong Zhou,He-Ping Zeng,Zi-Chun Hua 한국식품영양과학회 2010 Journal of medicinal food Vol.13 No.4

Buzhong Yiqi decoction (BYD) is a well-known ancient tonic prescription in traditional Chinese medicine (TCM). The purpose of this study is to identify active components of BYD involved in promoting proliferation of mesenchymal stem cells (MSCs) and to investigate its mechanism. BYD was extracted with petroleum ether, ethanol, and water. Evidence provided by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, bromodeoxyuridine, proliferation cell nuclear antigen immunoreactivity, cell cycle analysis, and gas chromatography-mass spectrometry indicated that hexadecanoic acid (HA) in BYD extracted with petroleum ether is the active compound responsible for increasing proliferation of MSCs. Western blot analysis show that HA significantly increase retinoic acid receptor (RAR) levels of MSCs, but not estrogen receptor, thyroid hormone receptor, vitamin D receptor, glucocorticoid receptor, and peroxisome proliferator-activated receptor. Reverse transcription-polymerase chain reaction revealed that HA significantly increased RAR mRNA levels. Furthermore, the mechanism of HA action depends on RAR pathway and up-regulates expression of mRNA for insulin-like growth factor-I, the target gene of RAR. Our findings have now allowed for a refinement in our understanding of TCM with respect to pharmacological regulation of stem cells and may be useful to stem cell biology and therapy.

A 5.6 kW 11.7 kW per kg Four-Phase Interleaved Buck Converter for the Unmanned Aerial Vehicle

Cheng Xu-Feng,Peng Zhenzhen,Yang Yulong,Liang Zhimin,Wu Chaofeng,Shao Zhiwei,Wang Dianlong 대한전기학회 2022 Journal of Electrical Engineering & Technology Vol.17 No.2

This paper proposed a 5.6 kW 11.7 kW/kg four-phase interleaved buck converter (FPIBC) for the unmanned aerial vehicle (UAV) low-voltage power system. The UAV mainly concerns the lightweight strategy and the power density of the DC-DC converter. We proposed a comprehensive lightweight strategy with the characteristics of reduced inductor current ripples, small size of fi lter inductors and capacitors, and high output power. The output current ripples are reduced by using interleaved modulation strategy and integrated CLC fi lters cascaded to the input side and output side respectively. In addition, the aluminum based printed circuit board (PCB) is used with SMD power transistors to obtain better heat dissipation capability without fans. With abovementioned methods, the designed DC-DC converter has a power of 5.6 kW @ 0.48 kg, the powerto-weight ratio is improved to be 11.7 kW/kg, and the power density is 3 W/cm 3 . The effi ciency of this DC-DC converter is up to 95.8%.