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991.
This paper concerns robust and efficient direction identification for a groupwise additive multiple-index model, in which each additive function has a single-index structure. Interestingly, without involving non-parametric approach, we show that the directions of all the index parameter vectors can be recovered by a simple linear composite quantile regression (CQR). As a specific application, a iterative-free CQR estimation procedure for the partially linear single-index model is proposed. Furthermore, it can also be used to develop a penalized CQR procedure for variable selection in the high-dimensional settings. The new method has superiority in robustness and efficiency by inheriting the advantage of the CQR approach. Simulation results and real-data analysis also confirm our method. 相似文献
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994.
Simultaneous Imaging of Endogenous Survivin mRNA and On‐Demand Drug Release in Live Cells by Using a Mesoporous Silica Nanoquencher 下载免费PDF全文
Peiyan Yuan Xin Mao Kok Chan Chong Jiaqi Fu Sijun Pan Shuizhu Wu Changmin Yu Shao Q. Yao 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(27)
The design of multifunctional drug delivery systems capable of simultaneous target detection, imaging, and therapeutics in live mammalian cells is critical for biomedical research. In this study, by using mesoporous silica nanoparticles (MSNs) chemically modified with a small‐molecule dark quencher, followed by sequential drug encapsulation, MSN capping with a dye‐labeled antisense oligonucleotide, and bioorthogonal surface modification with cell‐penetrating poly(disulfide)s, the authors have successfully developed the first mesoporous silica nanoquencher (qMSN), characterized by high drug‐loading and endocytosis‐independent cell uptake, which is able to quantitatively image endogenous survivin mRNA and release the loaded drug in a manner that depends on the survivin expression level in tumor cells. The authors further show that this novel drug delivery system may be used to minimize potential cytotoxicity encountered by many existing small‐molecule drugs in cancer therapy. 相似文献
995.
Immobilization of Pt Nanoparticles via Rapid and Reusable Electropolymerization of Dopamine on TiO2 Nanotube Arrays for Reversible SERS Substrates and Nonenzymatic Glucose Sensors 下载免费PDF全文
Jingsheng Cai Jianying Huang Mingzheng Ge James Iocozzia Zhiqun Lin Ke‐Qin Zhang Yuekun Lai 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(19)
Inspired by mussel‐adhesion phenomena in nature, polydopamine (PDA) coatings are a promising route to multifunctional platforms for decorating various materials. The typical self‐polymerization process of dopamine is time‐consuming and the coatings of PDA are not reusable. Herein, a reusable and time‐saving strategy for the electrochemical polymerization of dopamine (EPD) is reported. The PDA layer is deposited on vertically aligned TiO2 nanotube arrays (NTAs). Owing to the abundant catechol and amine groups in the PDA layer, uniform Pt nanoparticles (NPs) are deposited onto the TiO2 NTAs and can effectively prevent the recombination of electron–hole pairs generated from photo‐electrocatalysis and transfer the captured electrons to participate in the photo‐electrocatalytic reaction process. Compared with pristine TiO2 NTAs, the as‐prepared Pt@TiO2 NTA composites exhibit surface‐enhanced Raman scattering sensitivity for detecting rhodamine 6G and display excellent UV‐assisted self‐cleaning ability, and also show promise as a nonenzymatic glucose biosensor. Furthermore, the mussel‐inspired electropolymerization strategy and the fast EPD‐reduced nanoparticle decorating process presented herein can be readily extended to various functional substrates, such as conductive glass, metallic oxides, and semiconductors. It is the adaptation of the established PDA system for a selective, robust, and generalizable sensing system that is the emphasis of this work. 相似文献
996.
In Situ Observation of Crystallization of Methylammonium Lead Iodide Perovskite from Microdroplets 下载免费PDF全文
Yahui Li Zhenhao Zhao Feng Lin Xiaobing Cao Xian Cui Jinquan Wei 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(26)
It is of great importance to investigate the crystallization of organometallic perovskite from solution for enhancing performance of perovskite solar cells. Here, this study develops a facile method for in situ observation of crystallization and growth of the methylammonium lead iodide (MAPbI3) perovskite from microdroplets ejected by an alternating viscous and inertial force jetting method. It is found that there are two crystallization modes when MAPbI3 grows from the CH3NH3I (MAI)/PbI2/N,N‐dimethylformamide (DMF) solution: needle precursors and granular perovskites. Generally, needle Lewis adduct of MAPbI3·DMF tends to nucleate and grow from the solution due to low solubility of PbI2. The growth of MAPbI3·DMF depends on both the concentration of MAI and temperature. It tends to form large perovskite domains on substrates at high temperature. The MAPbI3·DMF coverts to nanocrystalline perovskite due to lattice shrinkage when DMF molecules escape from the Lewis adduct. Granular perovskite can also directly nucleate from the solution at high concentration of MAI due to compositional segregation. 相似文献
997.
Hua Yu Zhengzhong Yang Luojun Du Jing Zhang Jinan Shi Wei Chen Peng Chen Mengzhou Liao Jing Zhao Jianling Meng Guole Wang Jianqi Zhu Rong Yang Dongxia Shi Lin Gu Guangyu Zhang 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(7)
Control of the precise lattice alignment of monolayer molybdenum disulfide (MoS2) on hexagonal boron nitride (h‐BN) is important for both fundamental and applied studies of this heterostructure but remains elusive. The growth of precisely aligned MoS2 domains on the basal plane of h‐BN by a low‐pressure chemical vapor deposition technique is reported. Only relative rotation angles of 0° or 60° between MoS2 and h‐BN basal plane are present. Domains with same orientation stitch and form single‐crystal, domains with different orientations stitch and from mirror grain boundaries. In this way, the grain boundary is minimized and a continuous film stitched by these two types of domains with only mirror grain boundaries is obtained. This growth strategy is also applicable to other 2D materials growth. 相似文献
998.
The Electrochemical Response of Single Crystalline Copper Nanowires to Atmospheric Air and Aqueous Solution 下载免费PDF全文
Bowei Zhang Bensong Chen Junsheng Wu Shiji Hao Guang Yang Xun Cao Lin Jing Minmin Zhu Siu Hon Tsang Edwin Hang Tong Teo Yizhong Huang 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(10)
In this paper, single crystalline copper nanowires (CuNWs) have been electrochemically grown through anodic aluminum oxide template. The environmental stability of the as‐obtained CuNWs in both 40% relative humidity (RH) atmosphere and 0.1 m NaOH aqueous solution has been subsequently studied. In 40% RH atmosphere, a uniform compact Cu2O layer is formed as a function of exposure time following the logarithmic law and epitaxially covers the CuNW surfaces. It is also found that the oxide layers on CuNWs are sequentially grown when subjected to the cyclic voltammetry measurement in 0.1 m NaOH solution. An epitaxially homogeneous Cu2O layer is initially formed over the surface of the CuNW substrates by solid‐state reaction (SSR). Subsequently, the conversion of Cu2O into epitaxial CuO based on the SSR takes place with the increase of applied potential. This CuO layer is partially dissolved in the solution forming Cu(OH)2, which then redeposited on the CuNW surfaces (i.e., dissolution‐redeposition (DR) process) giving rise to a mixed polycrystalline CuO/Cu(OH)2 layer. The further increase of applied potential allows the complete oxidation of Cu2O into CuO to form a dual‐layer structure (i.e., CuO inner layer and Cu(OH)2 outer layer) with random orientations through an enhanced DR process. 相似文献
999.
Tissue Engineering: Effective Light Directed Assembly of Building Blocks with Microscale Control (Small 24/2017) 下载免费PDF全文
1000.
Cancer Multidrug Resistance: Safe and Effective Reversal of Cancer Multidrug Resistance Using Sericin‐Coated Mesoporous Silica Nanoparticles for Lysosome‐Targeting Delivery in Mice (Small 9/2017) 下载免费PDF全文