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Sub 5 nm

Fen Liao, Ling-Ying Shi, Li-Chen Cheng, Sangho Lee, Rong Ran, Kevin G Yager, Caroline A Ross
The self-assembly of a high-χ silicon-containing side-chain liquid crystalline block copolymer (LC BCP) in bulk and in thin films is reported, and the structural transition process from the hexagonally packed cylinder (HEX) to the body-centered cubic structure (BCC) in thin films was examined by both reciprocal and real space experimental methods. The block copolymer, poly(dimethylsiloxane-b-11-(4'-cyanobiphenyl-4-yloxy)undecylmethacrylate) (PDMS-b-P(4CNB11C)MA) with a molecular weight of 19.5 kg mol-1 and a volume fraction of PDMS 27% self-assembled in bulk into a hierarchical nanostructure of sub-20 nm HEX cylinders of PDMS with the P(4CNB11C)MA block exhibiting a smectic LC phase with a 1...
December 10, 2018: Nanoscale
H Saeed, A Hartland, N J Lehto, M Baalousha, M Sikder, D Sandwell, M Mucalo, D P Hamilton
Dissolved reactive phosphorous (DRP) in lake systems is conventionally considered to predominate over other dissolved P species, however, this view neglects an important set of interactions that occurs between P and reactive iron hydroxide surfaces. This study addresses the coupling of P with dispersed iron nanoparticles in lakes, an interaction that may fundamentally alter the bioavailability of P to phytoplankton. We used diffusive gradients in thin films (DGT) and ultrafiltration to study Fe-P coupling in the water column of a monomictic lake over a hydrological year...
December 10, 2018: Scientific Reports
Jun Ando, Akihiko Nakamura, Akasit Visootsat, Mayuko Yamamoto, Chihong Song, Kazuyoshi Murata, Ryota Iino
Gold nanoparticles (AuNPs) have been used as a contrast agent for optical imaging of various single biomolecules. Because AuNPs have high scattering efficiency without photobleaching, biomolecular dynamics have been observed with nanometer localization precision and sub-millisecond time resolution. To understand the working principle of biomolecular motors in greater detail, further improvement of the localization precision and time resolution is necessary. Here, we investigated the lower limit of localization precision achievable with AuNPs and the fundamental law, which determines the localization precision...
November 17, 2018: Biophysical Journal
Luís A Cabral, Fermin H Aragon, Leonardo Villegas-Lelovsky, Matheus P Lima, Waldemar Augusto de Almeida Macedo, Juarez L F Da Silva
Tuning the magnetic properties of materials is a demand of several technologies, however, their control is still a challenge. In this work, we combined experimental and theoretical techniques to investigate the handling of magnetic properties of the FeCo thin films via the thickness-tuning of a gold film used as substrate. We growth the samples by the deposition of polycrystalline FeCo thin films on Au underlayer at room temperature by magnetron sputtering technique, demonstrating that the sub 20 nm thickness gold underlayers have a lattice parameter dependence on their thickness, inducing stresses up to 3 % in sub 5 nm FeCo thin film deposited over it...
December 7, 2018: ACS Applied Materials & Interfaces
Ryan Kisslinger, Abdelrahman Mostafa Askar, Ujwal Kumar Thakur, Saralyn Riddell, Darren Dahunsi, Yun Zhang, Sheng Zeng, Ankur Goswami, Karthik Shankar
Anodically formed TiO2 nanotube arrays (TNTAs) constitute an optoelectronic platform that is being studied for use as a photoanode in photoelectrocatalytic cells, as an electron transport layer (ETL) in solar cells and photodetectors, and as an active layer for chemiresistive and microwave sensors. For optimal transport of charge carriers in these one-dimensional polycrystalline ordered structures, it is desirable to introduce a preferential texture with the grains constituting the nanotube walls aligned along the transport direction...
October 19, 2018: Nanotechnology
Arkadiusz Jarota, Ewa Pastorczak, Walid Tawfik, Bing Xue, Rafał Kania, Halina Abramczyk, Takayoshi Kobayashi
A diarylethene derivative, 1,2-bis(2,4-dimethyl-5-phenyl-3-thienyl)perfluorocyclopentene (DMP), is a photoswitch molecule utilizing a reversible aromatic ring-opening reaction. The quantum yield of the ring-opening reaction is however remarkably low. We investigate the origin of this behaviour by means of ultrafast transient absorption spectroscopy utilizing sub-10 fs pulses, which is an invaluable tool for simultaneously studying both the electronic and the vibrational molecular dynamics. Namely, a noncollinear optical parametric amplifier (NOPA) generating sub-10 fs pulses in the spectral range 605-750 nm is employed...
December 5, 2018: Physical Chemistry Chemical Physics: PCCP
Sergey Zherebtsov, Maxim Ozerov, Margarita Klimova, Nikita Stepanov, Tatyana Vershinina, Yulia Ivanisenko, Gennady Salishchev
The microstructure and microhardness evolution of a Ti-15(wt.%)Mo/TiB metal-matrix composite (MMC) during high-pressure torsion (HPT) at 400 °C was studied. The composite was fabricated by spark plasma sintering of a Ti, Mo and TiB₂ powders mixture at 1200 °C. In the initial condition, the structure of the composite consisted mainly of body-centered cubic (bcc) Ti solid solution and TiB whiskers. An increase in dislocation density, a considerable decrease in a grain size in the bcc Ti matrix, and breaking/rearrangement of the TiB whiskers were observed during HPT...
November 30, 2018: Materials
A-L Ronzani, A Hubert, F Pointurier, O Marie, N Clavier, A-C Humbert, J Aupiais, N Dacheux
RATIONALE: A multi-collector inductively coupled plasma (MC-ICP) mass spectrometer coupled to a UV ns-laser ablation (LA) system was used to measure uranium isotopic ratios (234 U/238 U, 235 U/238 U and 236 U/238 U) in single uranium particles of various sizes and isotopic compositions, including home-made sub-micrometric natural uranium particles of narrow size distribution (415 ± 60 nm). METHODS: The LA-ICP mass spectrometer was operated in wet plasma conditions thanks to simultaneous injection of the laser aerosol and water vapor through a desolvating nebulizer...
November 29, 2018: Rapid Communications in Mass Spectrometry: RCM
Kyoungjun Choi, Amirhossein Droudian, Roman M Wyss, Karl-Philipp Schlichting, Hyung Gyu Park
Reliable and large-scale manufacturing routes for perforated graphene membranes in separation and filtration remain challenging. We introduce two manufacturing pathways for the fabrication of highly porous, perforated graphene membranes with sub-100-nm pores, suitable for ultrafiltration and as a two-dimensional (2D) scaffold for synthesizing ultrathin, gas-selective polymers. The two complementary processes-bottom up and top down-enable perforated graphene membranes with desired layer number and allow ultrafiltration applications with liquid permeances up to 5...
November 2018: Science Advances
Sergey Kobtsev, Aleksey Ivanenko, Alexey Kokhanovskiy, Mikhail Gervaziev
This work presents implementation of a new approach to single-cascade Raman conversion of laser pulses from the spectral range around 1.1 µm into the 1.3-µm wavelength region. The proposed conversion technique relies on double-scale pico-femtosecond pulses for synchronous pumping of an external cavity made of phosphosilicate fiber with high-precision adjustment of pulse repetition rate to the inter-mode frequency of the external cavity. This enabled generation of double-scale pulses centered at 1270 nm featuring a record energy of 63 nJ and the pulse envelope duration of 88-180 ps with the sub-pulse duration of 200 fs...
November 12, 2018: Optics Express
Masatomo Yamagiwa, Takeo Minamikawa, Clément Trovato, Takayuki Ogawa, Dahi Ghareab Abdelsalam Ibrahim, Yusuke Kawahito, Ryo Oe, Kyuki Shibuya, Takahiko Mizuno, Emmanuel Abraham, Yasuhiro Mizutani, Tetsuo Iwata, Hirotsugu Yamamoto, Kaoru Minoshima, Takeshi Yasui
Digital holography (DH) is a promising method for non-contact surface topography because the reconstructed phase image can visualize the nanometer unevenness in a sample. However, the axial range of this method is limited to the range of the optical wavelength due to the phase wrapping ambiguity. Although the use of two different wavelengths of light and the resulting synthetic wavelength, i.e., synthetic wavelength DH, can expand the axial range up to several hundreds of millimeters, its axial precision does not reach sub-micrometer...
October 1, 2018: Optics Express
Jihoon Kim, Sun Jae Jeong, Sungwook Choi, Seul-Lee Lee, Min Seok Kim, Dokyeong Kim, Bong-Jun Kim, Yong Wook Lee
By incorporating a high-power 976 nm laser diode (LD), we demonstrated laser-regulated current switching in a two-terminal planar device based on a vanadium dioxide (VO₂) thin film. The VO₂ thin film was grown by pulsed laser deposition method and etched to sub-millimeter dimension for the fabrication of a two-terminal device. The reversible current switching was implemented by controlling the on/off state of the LD, which illuminates the VO₂-based device. The transient responses of the device currents were analyzed when the device was excited with laser pulses of various repetition rates of up to 5...
March 1, 2019: Journal of Nanoscience and Nanotechnology
Emma Shardlow, Cassandra Rao, Roman Sattarov, Ling Wu, Paul E Fraser, Christopher Exley
Islet amyloid polypeptide (IAPP1-37 ) or amylin is implicated in the aetiology of diabetes. It is found as amyloid along with its precursor ProIAPP1-48 in the islets of Langerhans in the pancreas. Metals have been implicated in amyloidogenesis of both IAPP and ProIAPP. Herein we have used dynamic light scattering (DLS) to investigate how Al(III) and Cu(II) influence aggregation of ProIAPP1-48 under near-physiological conditions and in a biologically-relevant timeframe. ProIAPP1-48 formed primarily sub-micron particles within 5 min (e...
January 2019: Journal of Trace Elements in Medicine and Biology
Joanna Wojciechowska, Elisa Gitzhofer, Jacek Grams, Agnieszka M Ruppert, Nicolas Keller
Ru/TiO₂ are promising heterogeneous catalysts in different key-reactions taking place in the catalytic conversion of biomass towards fuel additives, biofuels, or biochemicals. TiO₂ supported highly dispersed nanometric-size metallic Ru catalysts were prepared at room temperature via a solar light induced photon-assisted one-step synthesis in liquid phase, far smaller Ru nanoparticles with sharper size distribution being synthesized when compared to the catalysts that were prepared by impregnation with thermal reduction in hydrogen...
November 19, 2018: Materials
Leon G Leanse, Olivia D Harrington, Yanyan Fang, Imran Ahmed, Xueping Sharon Goh, Tianhong Dai
Antimicrobial resistance is a threat to public health that requires our immediate attention. With increasing numbers of microbes that are becoming resistant to routinely used antimicrobials, it is vital that we look to other, non-traditional therapies for the treatment of infections. Antimicrobial blue light (aBL) is an innovative approach that has demonstrated efficacy for the inactivation of an array of microbial pathogens. In the present study, we investigated the potential for resistance development to aBL in Gram-negative pathogenic bacteria by carrying out multiple aBL exposures on bacteria...
2018: Frontiers in Microbiology
Bin Yang, Xin Mao, Feng Hong, Weiwei Meng, Yuxuan Tang, Xusheng Xia, Songqiu Yang, Weiqiao Deng, Keli Han
Lead-free double perovskite nanocrystals (NCs), i.e. Cs2AgInxBi1xCl6 (x = 0, 0.25, 0.5 0.75 and 0.9), that can be tuned from the indirect bandgap (x = 0, 0.25 and 0.5) to the direct bandgap (x = 0.75 and 0.9) are designed. Direct-bandgap NCs exhibit 3 times greater absorption cross-section, lower sub-bandgap trap states, and >5 times photoluminescence quantum efficiency (PLQE) compared with those observed for indirect bandgap NCs (Cs2AgBiCl6). A PLQE of 36.6% for direct bandgap NCs is comparable to those observed for lead-perovskite NCs in the violet region...
November 19, 2018: Journal of the American Chemical Society
Wu Chen, Wen Yang, Pengyu Chen, Yongzhuo Huang, Feng Li
Disulfiram (DSF), an alcohol-aversion drug, has been explored for cancer treatment. Copper diethyldithiocarbamate (Cu(DDC)2 ) complex formed by DSF and copper ions is a major active ingredient for its anticancer activity. Direct administration of Cu(DDC)2 is a promising strategy to enhance the anticancer efficacy of DSF. However, efficient drug delivery remains a significant challenge for Cu(DDC)2 and hinders its clinical use. In this study, we developed a facile stabilized metal ion ligand complex (SMILE) method to prepare Cu(DDC)2 nanoparticles (NPs)...
November 16, 2018: ACS Applied Materials & Interfaces
Kai Wu, Marcel Tichem
Photonic packaging, which includes high-precision assembly of photonic sub-systems, is currently a bottleneck in the development of commercially-available integrated photonic products. In the pursuit of a fully-automated, high-precision, and cost-effective photonic alignment scheme for two multi-channel photonic chips, this paper explores different designs of the on-chip electrothermal actuators for positioning mechanically-flexible waveguide structures. The final alignment goal is ∼100 nm waveguide to waveguide...
September 27, 2018: Micromachines
Hongming Lyu, Parag Gad, Hui Zhong, V Reggie Edgerton, Aydin Babakhani
This work presents a miniaturized W-level implantable pulse generator (IPG) inductively powered at 430 MHz. Notches are intentionally applied to the incident power, which are replicated to precisely control the timing of the output pulses. Fabricated in 180 nm CMOS process, the concise circuitry occupies a pad-included footprint of 850 m 450 m and achieves a quiescent current consumption of 950 nA. To reduce the form factor, 401-457 MHz MedRadio-band is utilized to realize the induction link. The finalized assembly achieves one of the smallest dimensions (4...
November 9, 2018: IEEE Transactions on Biomedical Circuits and Systems
A I Dago, Y K Ryu, F J Palomares, R Garcia
Direct, robust, and high-resolution patterning methods are needed to downscale the lateral size of two-dimensional materials to observe new properties and optimize the overall processing of these materials. In this work, we report a fabrication process where the initial microchannel of a few-layer WSe2 field-effect transistor is treated by oxygen plasma to form a self-limited oxide layer on top of the flake. This thin oxide layer has a double role here. First, it induces the so-called p-doping effect in the device...
November 21, 2018: ACS Applied Materials & Interfaces
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