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Valentina Gregori, Arjan Gijsberts, Barbara Caputo
Domain adaptation methods have been proposed to reduce the training efforts needed to control an upper-limb prosthesis by adapting well performing models from previous subjects to the new subject. These studies generally reported impressive reductions in the required number of training samples to achieve a certain level of accuracy for intact subjects. We further investigate two popular methods in this field to verify whether this result also applies to amputees. Our findings show instead that this improvement can largely be attributed to a suboptimal hyperparameter configuration...
July 2017: IEEE ... International Conference on Rehabilitation Robotics: [proceedings]
Zhuangqiang Gao, Haihang Ye, Dianyong Tang, Jing Tao, Sanaz Habibi, Adriene Minerick, Dianping Tang, Xiaohu Xia
Au nanoparticles (AuNPs) as signal reporters have been utilized in colorimetric in vitro diagnostics (IVDs) for decades. Nevertheless, it remains a grand challenge to substantially enhance the detection sensitivity of AuNP-based IVDs as confined by the inherent plasmonics of AuNPs. In this work, we circumvent this confinement by developing a unique dual-functional AuNPs that were engineered by coating conventional AuNPs with ultrathin Pt skins of sub-10 atomic layers (i.e., Au@Pt NPs). The Au@Pt NPs retain the plasmonic activity of initial AuNPs, while possess ultrahigh catalytic activity enabled by Pt skins...
August 16, 2017: Nano Letters
Jindřich Mach, Pavel Procházka, Miroslav Bartošík, David Nezval, Jakub Piastek, Jan Hulva, Vojtěch Švarc, Martin Konečný, Lukáš Kormoš, Tomas Sikola
In this work we present the effect of low dose gallium (Ga) deposition (< 4 ML) performed in UHV (10-7 Pa) on the electronic doping and charge carrier scattering in graphene grown by chemical vapor deposition (CVD). In-situ graphene transport measurements performed with a graphene field-effect transistor (FET) structure show that at low Ga coverages a graphene layer tends to be strongly n-doped with an efficiency of 0.64 electrons per one Ga atom, while the further deposition and Ga cluster formation results in removing electrons from graphene (less n-doping)...
August 16, 2017: Nanotechnology
Deyang Chen, Christopher T Nelson, Xiaohong Zhu, Claudy R Serrao, James D Clarkson, Zhe Wang, Ya Gao, Shang-Lin Hsu, Liv R Dedon, Zuhuang Chen, Di Yi, Heng-Jui Liu, Dechang Zeng, Ying-Hao Chu, Jian Liu, Darrell G Schlom, Ramamoorthy Ramesh
A strain-driven orthorhombic (O) to rhombohedral (R) phase transition is reported in La-doped BiFeO3 thin films on silicon substrates. Biaxial compressive epitaxial strain is found to stabilize the rhombohedral phase at La concentrations beyond the morphotropic phase boundary (MPB). By tailoring the residual strain with film thickness, we demonstrate a mixed O/R phase structure consisting of O phase domains measuring tens of nanometers wide within a predominant R phase matrix. A combination of piezoresponse force microscopy (PFM), transmission electron microscopy (TEM), polarization-electric field hysteresis loop (P-E loop), and polarization maps reveal that the O-R structural change is an antiferroelectric to ferroelectric (AFE-FE) phase transition...
August 17, 2017: Nano Letters
Petr Špaček, Dianne T Keough, Marina Chavchich, Martin Dracinsky, Zlatko Janeba, Lieve Naesens, Michael D Edstein, Luke W Guddat, Dana Hocková
Acyclic nucleoside bisphosphonates (ANbPs) have previously been shown to be good inhibitors of human hypoxanthine-guanine phosphoribosyltransferase (HGPRT) and Plasmodium falciparum (Pf) hypoxanthine-guanine-xanthine phosphoribosyltransferase (PfHGXPRT). Based on this scaffold, a new series of ANbPs was synthesized. One of these new ANbPs, [3-(guanine-9-yl)-2-((2-phosphonoethoxy)methyl)propoxy]methylphosphonic acid, exhibited Ki values of 6 and 70 nM for human HGPRT and Pf HGXPRT, respectively. These low Ki values were achieved by inserting an extra carbon atom in the linker connecting the N9 atom of guanine to one of the phosphonate groups...
August 16, 2017: Journal of Medicinal Chemistry
Thomas Schmaltz, Bastian Gothe, Andreas Krause, Susanne Leitherer, Hans-Georg Steinrück, Michael Thoss, Timothy Clark, Marcus Halik
Self-assembled monolayer field-effect transistors (SAMFETs) are not only a promising new type of organic electronic device but also allow uniquely detailed analyses of structure-property correlations. The influence of the morphology on the charge transport is particularly pronounced, due to the confined monolayer of 2D-π-stacked organic semiconductor molecules. The morphology, in turn, is governed by relatively weak van-der-Waals interactions and is thus prone to dynamic structural fluctuations. Accordingly, combining electronic and physical characterization and time-averaged X-ray analyses with the dynamic information available at atomic resolution from simulations, allows us to characterize self-assembled monolayer (SAM-) based devices in unprecedented detail...
August 16, 2017: ACS Nano
Amy Lynne Bondy, Rachel M Kirpes, Rachel Leah Merzel, Kerri A Pratt, Mark M Banaszak Holl, Andrew P Ault
Chemical analysis of atmospheric aerosols is an analytical challenge, as aerosol particles are complex chemical mixtures that can contain hundreds to thousands of species in attoliter volumes at the most abundant sizes in the atmosphere (~100 nm). These particles have global impacts on climate and health, but there are few methods available that combine imaging and the detailed molecular information from vibrational spectroscopy for individual particles <500 nm. Herein, we show the first application of atomic force microscopy with infrared spectroscopy (AFM-IR) to detect trace organic and inorganic species and probe intraparticle chemical variation in individual particles down to 150 nm...
August 16, 2017: Analytical Chemistry
Bin-Bin Wang, Yong-Chang Han, Wei Gao, Shu-Lin Cong
The atom-atom-ion three-body recombination (TBR) of mixed (4)He and X(-) (X = H or D) systems is investigated by solving the Schrödinger equation using the adiabatic hyperspherical representation method. It is shown that the dominant products after a TBR in the ultracold limit (E ≤ 0.1 mK × kB) are different for the two systems. For the (4)He(4)HeH(-) system, the rate of TBR into the (4)HeH(-) ion is nearly two orders of magnitude larger than that of TBR into the neutral (4)He2 molecule. In contrast, the yield of (4)He2 is a little higher than that of (4)HeD(-) for the (4)He(4)HeD(-) system...
August 16, 2017: Physical Chemistry Chemical Physics: PCCP
Kaituo Liu, James Pritchard, Li Lu, Robbert van Putten, M W G M Tiny Verhoeven, Mike Schmitkamp, Xiaoming Huang, Laurent Lefort, Christopher J Kiely, Emiel J M Hensen, Evgeny A Pidko
The addition of Re to Ni on TiO2 yields efficient catalysts for the hydrogenation of acids and esters to alcohols under mild conditions. Rhenium promotes the formation of atomically dispersed and sub-nanometre-sized bimetallic species interacting strongly with the oxide support.
August 16, 2017: Chemical Communications: Chem Comm
Soyeong Kang, Seok Hyeon Jang, Juyeol Lee, Dong-Gil Kim, Mijin Kim, Wook Jeong, Young Ho Rhee
Catalytic asymmetric synthesis of N-heterocyclic glycosides free of protecting and directing groups is reported. The key reaction is highlighted by the atom-efficient and regioselective addition of unprotected pyrimidines to highly functionalized alkoxyallene. Numerous acyclic and cyclic N-heterocyclic glycosides are accessed with minimal formation of organic byproducts. The synthetic utility of the reaction is demonstrated by the first catalytic asymmetric synthesis of anticancer pharmaceutical (-)-Tegafur and stereoselective synthesis of an oxepane nucleoside derivative...
August 16, 2017: Organic Letters
Martin Brehm, Ghulam Saddiq, Tobias Watermann, Daniel Sebastiani
In this study, we investigate the effect of a series of additive molecules with different types of philicities on the structure and dynamics of DPPC bilayers. To this aim, we performed extensive force field molecular dynamics simulations of the systems, using our recently developed perfluoroalkane force field. We found that addition of perfluoro-n-decane and fluorotelomer alcohol at 323 K leads to a phase transition of the membrane from liquid crystalline to gel phase, whereas the addition of n-decane and partially fluorinated n-decane leaves the liquid crystalline phase intact...
August 16, 2017: Journal of Physical Chemistry. B
Dong Wang, Ken Nakajima, Feng Liu, Shaowei Shi, Thomas P Russell
The large Young's modulus difference between chemically modified fullerene (PCBM) and a conjugated polymer was used to nanomechanically map the diffusion of PCBM into PTB7, a high efficiency low band gap conjugated polymer. The sharp tip in nanomechanical atomic force microscopy (AFM) ensures a high-resolution nanomechanical characterization of the diffusion front, with the intrinsic benefits of revealing the mechanical properties of the mixtures. Localized structure changes induced by diffusion were investigated by grazing incidence x-ray diffraction methods...
August 16, 2017: ACS Nano
Leonid P Salamakha, Oksana Sologub, Berthold Stöger, Peter Franz Rogl, Monika Waas, Volodymyr B Kapustianyk, Ernst Bauer
Two borides, ScRu2B3 and Sc2RuB6, were obtained by argon-arc melting of the elements followed by annealing at 800 °C. ScRu2B3 exhibits a new structure type with the space group Cmcm (a = 3.0195(2) Å, b = 15.4056(8) Å, c = 5.4492(3) Å; single crystal X-ray data; RF(2) = 0.0105). Sc2RuB6 adopts the Y2ReB6-type structure (space group Pbam; a = 8.8545(2) Å, b = 11.1620(3) Å, c = 3.4760(1) Å; single crystal X-ray data; RF(2) = 0.0185). ScRu2B3 displays an unusual intergrowth of CeCo3B2- and AlB2-related slabs; a striking feature is a boat configuration of puckered boron hexagons within infinite graphite like boron layers (6(3) nets)...
August 16, 2017: Inorganic Chemistry
Huan-Pu Chang, En-De Chu, Yu-Ting Yeh, Yueh-Chun Wu, Fang-Yuh Lo, Wei-Hua Wang, Ming-Yau Chern, Hsiang-Chih Chiu
Oxygen vacancy is the most studied point defect and has been found to significantly influence the physical properties of zinc oxide (ZnO). By using atomic force microscopy (AFM), we show that the frictional properties on the ZnO surface at the nanoscale greatly depend on the amount of oxygen vacancies present in the surface layer and the ambient humidity. The photocatalytic effect (PCE) is used to qualitatively control the amount of oxygen vacancies in the surface layer of ZnO and reversibly switch the surface wettability between hydrophobic and superhydrophilic states...
August 16, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Qing Lv, Wenyan Si, Ze Yang, Ning Wang, Zeyi Tu, Yuanping Yi, Changshui Huang, Li Jiang, Mingjia Zhang, Jianjiang He, Yun-Ze Long
Metal-free catalysts for oxygen reduction reaction (ORR) are the desired materials for low-cost proton exchange membrane fuel cells. Graphdiyne (GDY), a novel type of 2D carbon allotrope, is featured by sp and sp2 hybridized carbon, different from the other existed carbon materials. Thus nitrogen (N) can be doped in new styles by substituting sp hybridized carbon atoms, effective for ORR, which has been displayed in this study using both experimental and theorical technologies. The N doped GDY was synthesized with pyridine and NH3 as N sources, successively, expressing similar electrocatalytic activity at potential above 0...
August 16, 2017: ACS Applied Materials & Interfaces
Lian Duan, Zhen Cao, Levent Yobas
Continuous-flow electrophoresis of macromolecules is demonstrated using an integrated capillary-well sieve arranged into a two-dimensional anisotropic array on silicon. The periodic array features thousands of entropic barriers, each resulting from an abrupt interface between a 2-μm-deep well (channel) and a 70-nm capillary. These entropic barriers owing to two-dimensional confinement within the capillaries are vastly steep in relation to those arising from slits featuring one-dimensional confinement. Thus, the sieving mechanisms can sustain relatively large electric field strengths over a relatively small array area...
August 16, 2017: Analytical Chemistry
Ting Zhou, Zhiqing Zhang, Xuemei Zhang, Chen Wang, Guiying Xu, Yanlian Yang
We report interesting hierarchical self-assembled architectures from a designed amphiphilic peptide. The bisignate cotton effects in circular dichroism spectra show typical peptide aggregation-induced. The observation of peptide assembly structures from initial particles and fibrils to ribbon structures is supported by microscopy (atomic force microscopy and transmission electron microscopy). The visualization of individual peptide at the single molecular level offered insights of the intermolecular interactions responsible for the formation of aggregates, which is investigated by scanning tunneling microscopy...
August 15, 2017: Journal of Peptide Science: An Official Publication of the European Peptide Society
Hailiang Huang, Benbin Zhong, Xihong Zu, Hongsheng Luo, Wenjing Lin, Minghai Zhang, Yazhou Zhong, Guobin Yi
Ordered nanopatterns of triblock copolymer polystyrene-block-poly(2-vinylpyridine)-block- poly (ethylene oxide)(PS-b-P2VP-b-PEO) have been achieved by the addition of lithium chloride (LiCl). The morphological and structural evolution of PS-b-P2VP-b-PEO/LiCl thin films were systematically investigated by varying different experimental parameters, including the treatment for polymer solution after the addition of LiCl, the time scale of ultrasonic treatment and the molar ratio of Li(+) ions to the total number of oxygen atoms (O) in PEO block and the nitrogen atoms (N) in P2VP block...
August 15, 2017: Nanoscale Research Letters
P M Angel, D A Narmoneva, M K Sewell-Loftin, C Munjal, L Dupuis, B J Landis, A Jegga, C B Kern, W D Merryman, H S Baldwin, G M Bressan, Robert B Hinton
Aortic valve (AV) disease involves stiffening of the AV cusp with progression characterized by inflammation, fibrosis, and calcification. Here, we examine the relationship between biomechanical valve function and proteomic changes before and after the development of AV pathology in the Emilin1-/- mouse model of latent AV disease. Biomechanical studies were performed to quantify tissue stiffness at the macro (micropipette) and micro (atomic force microscopy (AFM)) levels. Micropipette studies showed that the Emilin1-/- AV annulus and cusp regions demonstrated increased stiffness only after the onset of AV disease...
August 15, 2017: Annals of Biomedical Engineering
Michael Fischer
Zeolites and structurally related materials (zeotypes) have received considerable attention as potential adsorbents for selective carbon dioxide adsorption. Within this group, zeotypes with aluminophosphate composition (AlPOs) could be an interesting alternative to the more frequently studied aluminosilicate zeolites. So far, however, only a few AlPOs have been characterised experimentally in terms of their CO2 adsorption properties. In this study, force-field based grand-canonical Monte Carlo (GCMC) simulations were used to evaluate the potential of AlPOs for CO2/N2 separation, a binary mixture that constitutes a suitable model system for the removal of carbon dioxide from flue gases...
August 16, 2017: Physical Chemistry Chemical Physics: PCCP
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