Yang Yang

Bio: Yang Yang is an academic researcher from Chinese Academy of Sciences. The author has contributed to research in topics: Medicine & Computer science. The author has an hindex of 171, co-authored 2644 publications receiving 153049 citations. Previous affiliations of Yang Yang include Zhejiang University & Northwest Normal University.

Potassium-Presenting Zinc Oxide Surfaces Induce Vertical Phase Separation in Fullerene-Free Organic Photovoltaics.

Abstract: Bulk heterojunction (BHJ) structure based organic photovoltaics (OPVs) have recently showed great potential for achieving high power conversion efficiencies (PCEs). An ideal BHJ structure would feature large donor/acceptor interfacial areas for efficient exciton dissociation and gradient distributions with high donor and acceptor concentrations near the anode and cathode, respectively, for efficient charge extraction. However, the random mixing of donors and acceptors in the BHJ often suffers the severe charge recombination in the interface, resulting in poor charge extraction. Herein, we propose a new approach-treating the surface of the zinc oxide (ZnO) as an electron transport layer with potassium hydroxide-to induce vertical phase separation of an active layer incorporating the nonfullerene acceptor IT-4F. Density functional theory calculations suggested that the binding energy difference between IT-4F and the PBDB-T-2Cl, to the potassium (K)-presenting ZnO interface, is twice as strong as that for IT-4F and PBDB-T-2Cl to the untreated ZnO surface, such that it would induce more IT-4F moving toward the K-presenting ZnO interface than the untreated ZnO interface thermodynamically. Benefiting from efficient charge extraction, the best PCEs increased to 12.8% from 11.8% for PBDB-T-2Cl:IT-4F-based devices, to 12.6% from 11.6% for PBDB-T-2Cl:Y1-4F-based devices, to 13.5% from 12.2% for PBDB-T-2Cl:Y6-based devices, and to 15.7% from 15.1% for PM6:Y6-based devices.

Selective recognition of co-assembled thrombin aptamer and docetaxel on mesoporous silica nanoparticles against tumor cell proliferation.

Abstract: Generally, tumor development relies on the material, energy, signal transduction in the extracellular matrix and intracellular environment. An optimal systematic approach for cancer treatment can cut off the connection between the tumor cell and extracellular matrix and inhibit the intracellular activity. The combination of two or more therapeutic approaches can cooperatively promote tumor suppression and is a very effective strategy for synergistic or combined anticancer treatment. Recent attention has been devoted to the engineering of specialized vehicles that encapsulate traditional chemotherapeutic drugs for stimuli-responsive release, and the targeting of these vehicles to tumor cells with highly efficient ligands that selectively recognize tumor-associated or tumor-specific antigens. It has been found that nanoscale vehicles can offer prolonged circulation times and selective binding to cancer tissues through enhanced permeation and retention effects. Importantly, the size of these nanocarriers, in contrast to single molecules, allows them to provide a larger drug payload and to achieve higher targeting specificity. A wide variety of targeting molecules have been synthesized or separated for use in cancer therapy, including peptides, oligosaccharides or humanized antibodies. Interestingly, nucleic acid ligands, also called aptamers, have been developed as a novel class of targeting molecules for therapeutic and diagnostic applications. Aptamers are single-stranded DNA or RNA oligonucleotides that can fold by intramolecular interaction into specific three-dimensional conformations to recognize various kinds of targets with high affinity and specificity. As the first selected aptamer, 15-mer thrombin binding aptamer (TBA), which can fold into a compact intramolecular tetraplex with an antiparallel orientation of strands in the chair-like conformation, inhibits the enzymatic function of thrombin. The significant neoplastic biological effect of thrombin involves clotting-dependent mechanism and protease-activated receptor-1 (PAR-1) related signaling; this leads to several tumor functions, specifically proliferation and angiogenesis. To the best of our knowledge, although a considerable amount of research has been carried out to exploit TBA in the construction of biosensors, molecular machines, and anticoagulants, 32] little has been done to employ TBA to target thrombin for disturbing fibrin formation and suppressing tumor cell growth by restraining the unique proteolytic ability of thrombin and further breaking related signal transduction pathways. Here, we report a TBA-tethered lipid-coated mesoporous silica nanoparticle (TBA–lipid–MSN) hybrid as an extraand intracellular anticancer nanocarrier. A potent anticancer drug, docetaxel (Dtxl), was incorporated into this hybrid system. Selective recognition and drug release were demonstrated by using this co-assembled delivery platform (Scheme 1). Briefly, the modified thrombin binding aptamer, 5’-GGTTG GTGTG GTTGG AAAAA AAAAA AAAAA-C18-spacer-3 (TBAA15-C18) was reconstituted into hydrogenated soybean phosphatidylcholine (HSPC), mPEG2000–distearoylphosphatidylethanolamine (mPEG2000–DSPE) and docetaxel containing mixed lipid vesicles. The obtained vesicles were spread on the outer surface of MSNs, which were synthesized by a base-catalyzed sol-gel method. Introduction of MSN cores is helpful to improve the mechanical stability of aptamer–liposome conjugation. The final formulation obtained was 1 mg TBAA15– lipid–Dtxl–MSN with 3 nmol Dtxl and about 0.44 nmol TBAA15. After TBAA15–lipid–Dtxl–MSN were co-cultured with HeLa cells and thrombin, the co-assembled bioconjugates were expected to not only suppress cell growth in the extracellular matrix based on the specific antithrombin characteristics of the aptamer by disturbing PAR-1 receptor signaling, but also to achieve a much more effective cytotoxicity in the cytoplasm because of the contribution of Dtxl. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were performed to examine the self-assembly of the TBAA15–lipid–Dtxl–MSN bioconjugates. The monodispersed short, rod-shaped MSNs with a diameter of 100–200 nm and aspect ratio of about 2, are shown in Figure S1A in the Supporting Information. The [a] L. Gao, Dr. Y. Cui, Dr. J. Fei, Prof. Dr. J. Li Beijing National Laboratory for Molecular Sciences Key Laboratory of Colloid and Interface Science Center for Molecular Sciences, Institute of Chemistry Chinese Academy of Sciences, Zhong Guan Cun Beijing, 100190 (P.R. China) Fax: (+86)10-8261-4087 E-mail : jbli@iccas.ac.cn [b] Prof. Dr. Q. He Micro/Nano Technology Research Centre Harbin Institute of Technology, Harbin, 150080 (P.R. China) [c] Dr. Y. Yang National Center for Nanoscicence and Technology No. 11, Bei Yi Tiao, Zhong Guan Cun, Beijing, 100190 (P.R. China) Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/chem.201101658.

Incorporation of Cu-Nx cofactors into graphene encapsulated Co as biomimetic electrocatalysts for efficient oxygen reduction.

Abstract: Unlike metals with incomplete d-shells such as Pt and Fe, copper (Cu) with a filled d-electron shell is generally regarded as a sluggish oxygen reduction reaction (ORR) electrocatalyst. However, laccase and other copper enzymes could catalyze the ORR efficiently in nature. Inspired by this, we incorporated Cu-Nx cofactors (Cu-N2 and Cu-N4) into graphene encapsulated Co frameworks by direct annealing of MOFs with a post etching process. The bioinspired electrocatalyst exhibits excellent performance and stability for ORR which is comparable to or even better than Pt/C. Meanwhile, it also illustrates a fantabulous performance in a zinc-air battery device. The excellent performance can be ascribed to the abundant atomically dispersed Cu-Nx cofactors in the graphene frameworks confirmed by aberration corrected HAADF-STEM and XAFS analyses. Density functional theory calculations suggest that when Cu atoms are coordinated with the surrounding N atoms, the valence electrons of Cu atoms will transfer to nitrogen atoms, simultaneously tuning the d electronic states near the Fermi level to realize fast ORR kinetics.

Energy transfer within small molecule/conjugated polymer blends enhances photovoltaic efficiency

Abstract: In this study, we employed ternary blends capable of energy transfer—a synthesized high-band-gap small molecule (SM-4OMe) comprising benzodithiophene (BDT) and rhodanine units (a molecular structure that was designed for energy transfer), a low-band-gap polymer (PTB7-TH) comprising BDT and thienothiophene units with desired packing orientation, and a fullerene—as active layers for single-junction photovoltaic devices. The light absorption of the small molecule and the polymer was partially complementary, owing to their band gap difference, thereby broadening the absorption spectrum of solar light while maintaining the energy band structures that facilitated energy and charge transfer. The synthesized small molecule SM-4OMe and the PTB7-TH had somewhat similar chemical structures—with the same planar BDT donor units—and thus allowed sufficient mixing between them for energy transfer to take place. The power conversion efficiency of a device incorporating a ternary blend of PTB7-TH:SM-4OMe:PC71BM (0.9 : 0.1 : 1.5, w/w/w) as the active layer, processed with diiodooctane (2 vol%) in chlorobenzene, was 10.4%, which is higher than the value of 8% of the corresponding device incorporating PTB7-TH:PC71BM (1 : 1.5, w/w)—an increase of 30%. We attribute this enhancement to the energy transfer from the high-band-gap small molecule SM-4OMe to the low-band-gap polymer PTB7-TH and to the optimal phase-separated bulk heterojunction morphology that comprises a mean PC71BM cluster size of 6 nm, which is lower than 12 nm for the PTB7-TH and PC71BM binary blends, and slightly better in-plane packing, arising from the inducements of the presence of SM-4OMe. This approach provides a facile and effective way to enhance the power conversion efficiency of single junction organic photovoltaics.

Joint Task Offloading and Caching for Massive MIMO-Aided Multi-Tier Computing Networks

Abstract: In this paper, a massive multiple-input multiple-output (MIMO) relay assisted multi-tier computing (MC) system is employed to enhance the task computation. We investigate the joint design of the task scheduling, service caching and power allocation to minimize the total task scheduling delay. To this end, we formulate a robust non-convex optimization problem taking into account the impact of imperfect channel state information (CSI). In particular, multiple task nodes (TNs) offload their computational tasks either to computing and caching nodes (CCN) constituted by nearby massive MIMO-aided relay nodes (MRN) or alternatively to the cloud constituted by nearby fog access nodes (FAN). To address the non-convexity of the optimization problem, an efficient alternating optimization algorithm is developed. First, we solve the non-convex power allocation optimization problem by transforming it into a linear optimization problem for a given task offloading and service caching result. Then, we use the classic Lagrange partial relaxation for relaxing the binary task offloading as well as caching constraints and formulate the dual problem to obtain the task allocation and software caching results. Given both the power allocation, as well as the task offloading and caching result, we propose an iterative optimization algorithm for finding the jointly optimized results. The simulation results demonstrate that the proposed scheme outperforms the benchmark schemes, where the power allocation may be controlled by the asymptotic form of the effective signal-to-interference-plus-noise ratio (SINR).

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Fast parallel algorithms for short-range molecular dynamics

Abstract: Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

Electronics and optoelectronics of two-dimensional transition metal dichalcogenides.

Abstract: Single-layer metal dichalcogenides are two-dimensional semiconductors that present strong potential for electronic and sensing applications complementary to that of graphene.