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Surface Orientation

David Sowah-Kuma, Kyle M Fransishyn, Chelsea Cayabyab, Michael W Martynowycz, Ivan Kuzmenko, Matthew F Paige
Synchrotron-based X-ray scattering measurements of phase-separated surfactant monolayers at the air-water interface provide molecular-level structural information about the packing and ordering of film components. In this work, grazing incidence X-ray diffraction (GIXD) and X-ray reflectivity (XR) measurements were used to collect crystallographic structural information for binary mixed monolayers of arachidic acid (AA, C19H39COOH) with perfluorotetradecanoic acid (PA, C13F27COOH), a system that has previously been investigated using a variety of thermodynamic and micron-scale structural characterization methods...
August 13, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Thalat Theresa Monajemi, Ethan Avila Ruiz
This work investigated the application of plastic scintillation detectors (PSDs) in dosimetry measurements on the surface of a phantom in megavoltage photon and electron beams. Emission spectra associated with fluorescence in the PMMA optical fibre, Cerenkov in the optical fibre, and the signal from the scintillator were characterized with a spectrophotometer. The angular dependence of the PSD response was studied with the PSD both in the plane and perpendicular to the plane of gantry rotation. Two methods of stem correction were investigated: stem subtraction and full spectral correction...
August 13, 2018: Physics in Medicine and Biology
Timothy Robson, Deepan S H Shah, Alexandra S Solovyova, Jeremy H Lakey
Functional protein-gold nanoparticle (AuNP) conjugates have a wide variety of applications including biosensing and drug delivery. Correct protein orientation, which is important to maintain functionality on the nanoparticle surface, can be difficult to achieve in practice, and dedicated protein scaffolds have been used on planar gold surfaces to drive the self-assembly of oriented protein arrays. Here we use the transmembrane domain of Escherichia coli outer membrane protein A (OmpATM ) to create protein-AuNP conjugates...
July 27, 2018: ACS applied nano materials
Sukjae Jang, Dabin Son, Sunbin Hwang, Minji Kang, Seoung-Ki Lee, Dae-Young Jeon, Sukang Bae, Sang Hyun Lee, Dong Su Lee, Tae-Wook Kim
Low voltage operational organic transistors (< 4 V) based on pentacene were successfully fabricated with hybrid dielectric films composed of aluminum oxide using atomic layer deposition and various phosphonic acid-based self-assembled monolayers as the gate dielectrics. High capacitances up to 279 nF/cm2 , low leakage current densities of 10-8  A/cm2 at 6 V, and high breakdown fields up to 7.5 MV/cm were obtained. The transistors with the octadecylphosphonic acid hybrid dielectric exhibited an improved saturation mobility of 0...
2018: Nano Convergence
Bärbel Krause, Dmitry S Kuznetsov, Andrey E Yakshin, Shyjumon Ibrahimkutty, Tilo Baumbach, Fred Bijkerk
Lanthanum and lanthanum nitride thin films were deposited by magnetron sputtering onto silicon wafers covered by natural oxide. In situ and real-time synchrotron radiation experiments during deposition reveal that lanthanum crystallizes in the face-centred cubic bulk phase. Lanthanum nitride, however, does not form the expected NaCl structure but crystallizes in the theoretically predicted metastable wurtzite and zincblende phases, whereas post-growth nitridation results in zincblende LaN. During deposition of the initial 2-3 nm, amorphous or disordered films with very small crystallites form, while the surface becomes smoother...
August 1, 2018: Journal of Applied Crystallography
M A Chakhoum, A Boukhachem, M Ghamnia, N Benameur, N Mahdhi, K Raouadi, M Amlouk
This work covers some physical properties of Sr-doped NiO sprayed thin films at various concentrations (0 to 4%) prepared on glass substrates. Structural properties by using X-ray diffraction (XRD) show that all films have a cubic structure with (111) orientation. The stress, estimated by adjusting the XRD diffraction peaks increases with the doping concentration. Also, the grain size decreases with the doping concentration. On the other hand, the stacking fault probability has been discussed in terms of Sr doping level...
July 25, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Shusaku Nagano
Rod-like liquid-crystalline (LC) mesogens preferentially adopt a homeotropic orientation by excluded volume effects at the free surface in side-chain LC (SCLC) polymer films. The homeotropic orientation is not advantageous for in-plane LC alignment processes. Surface segregation of polymers is the phenomenon in which one component with a low surface free energy covers the surface in a two or more polymer mixture or block copolymer film. In SCLC block copolymer films, the surface segregation structure induces a random planar orientation due to the formation of a microphase-separated interface parallel to the substrate via the covering of one of the segregated polymer block...
August 10, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Zhiyuan Zhu, Yuanfei Cai, Kexing Song, Yanjun Zhou, Jiasheng Zou
The precipitation sequence of a Cu-Ni-Be alloy is: α-Cu supersaturated solid solution → Guinier-Preston (G.P.) zones → metastable γ″ → γ' → stable γ (NiBe) phase. The micro-hardness and electrical conductivity during the aging process were measured. The precipitation characteristics and the distribution of the γ″ phase, under peak aging conditions, were analyzed by X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area diffraction pattern (SADP), and high-resolution transmission electron microscopy (HRTEM)...
August 9, 2018: Materials
Frederic Mentink-Vigier, Ildefonso Marin-Montesinos, Anil P Jagtap, Thomas Halbritter, Johan Van Tol, Sabine Hediger, Daniel Lee, Snorri Th Sigurdsson, Gaël De Paëpe
We introduce a new family of highly efficient polarizing agents for dynamic nuclear polarization (DNP)-enhanced nuclear magnetic resonance (NMR) applications, composed of asymmetric bis-nitroxides, in which a piperidine-based radical and a pyrrolinoxyl or a proxyl radical are linked together. The design of the AsymPol family was guided by the use of advanced simulations that allow computation of the impact of the radical structure on DNP efficiency. These simulations suggested the use of a relatively short linker with the intention to generate a sizable intramolecular electron dipolar coupling / J-exchange interaction, while avoiding parallel nitroxide orientations...
August 10, 2018: Journal of the American Chemical Society
Ryutaro Souda, Takashi Aizawa
Graphite is hydrophobic in nature, but the crystallization kinetics and dewetting transition of thin water films deposited onto graphite are distinct from those on typical hydrophobic substrates. To clarify the origin of these behaviors, we investigated the crystallization kinetics of thin water films on graphite in terms of the initial film thickness, deposition temperature, and template effects of adspecies based on reflection high-energy electron diffraction (RHEED) images; the film morphology change was analyzed using time-of-flight secondary ion mass spectrometry (TOF-SIMS)...
August 10, 2018: Physical Chemistry Chemical Physics: PCCP
Yong-Gyun Jung, Young-Ran Yun, Suk-Heung Song, Wook Park
Background: Pen-based devices have emerged as useful tools for measuring pH and glucose, and for fabricating microchannels and microarrays. Pen-based devices take advantage of flexible patterning, inexpensive costs, and small volumes, thereby saving time and increasing efficiency. We have developed a gradient nib marker pen device that generated simultaneously different antibiotic concentrations in bacteria antibiotic susceptibility testing (AST). Methods: The device can deposit on the target surface with the antibiotic gradient...
August 13, 2018: Journal of Korean Medical Science
Jing Xia, Fan Wang, Yu Meng, Zhengwang Wu, Li Wang, Weili Lin, Caiming Zhang, Dinggang Shen, Gang Li
The cortical surface of the human brain expands dynamically and regionally heterogeneously during the first postnatal year. As all primary and secondary cortical folds as well as many tertiary cortical folds are well established at term birth, the cortical surface area expansion during this stage is largely driven by the increase of surface area in two orthogonal orientations in the tangent plane: 1) the expansion parallel to the folding orientation (i.e., increasing the lengths of folds) and 2) the expansion perpendicular to the folding orientation (i...
July 21, 2018: Medical Image Analysis
Dengke Shen, Gang Wang, Zhichang Liu, Peng Li, Kang Cai, Chuyang Cheng, Yi Shi, Ji-Min Han, Chung-Wei Kung, Xirui Gong, Qinghui Guo, Hongliang Chen, Andrew Chi-Hau Sue, Youssry Y Botros, Antonio Facchetti, Omar K Farha, Tobin J Marks, J Fraser Stoddart
A class of metal-organic frameworks (MOFs)-namely CD-MOFs-obtained from natural products has been grown in an epitaxial fashion as films on the surfaces of glass substrates, which are modified with self-assembled monolayers (SAMs) of γ-cyclodextrin (γ-CD) molecules. The SAMs are created by host-guest complexation of γ-CD molecules with surface-functionalized pyrene units. The CD-MOF film has a continuous polycrystalline morphology with a structurally out-of-plane (c-axial) orientation, covering an area of several square mm with a thickness of ~2 µm...
August 9, 2018: Journal of the American Chemical Society
Mihir R Khadilkar, Arash Nikoubashman
Confinement effects are critical for stiff macromolecules in biological cells, vesicles, and other systems in soft matter. For these molecules, the competition between the packing entropy and the enthalpic cost of bending is further shaped by strong confinement effects. Through coarse-grained molecular dynamics simulations, we explore the self-assembly of semiflexible polymers confined in thin spherical shells for various chain lengths, chain stiffnesses, and shell thicknesses. Here, we focus on the case where the contour and persistence length of the polymers are comparable to the radius of the confining cavity...
August 9, 2018: Soft Matter
Wenyan Yin, Dongqing Ma, Jie Yu, Xiao Zhang, Linqiang Mei, Yan Zu, Lijuan An, Zhanjun Gu
Abnormal H2O2 and cholesterol levels are closely related to many diseases. Here, we reported a facile process for synthesis of oxidized glutathione (GSSG) modified MoS2 nanosheets (MoS2-GSSG NSs). The biocompatible MoS2-GSSG NSs have good dispersibility and high affinity to the substrate 3, 3', 5, 5'-tetramethylbenzidine (TMB), which are beneficial for improving peroxidase-like catalytic activity of MoS2. The high peroxidase-like activity of MoS2-GSSG NSs was applied as a robust nanoplatform for low cost, rapid, and highly effective colorimetric detection of H2O2 and total/free cholesterol...
August 9, 2018: Chemistry: a European Journal
Armando Rojas, Paulina Araya, Jacqueline Romero, Fernando Delgado-López, Ileana Gonzalez, Carolina Añazco, Ramon Perez-Castro
Tumors are complex tissues composed of variable amounts of both non-cellular components (matrix proteins) and a multitude of stromal cell types, which are under an active cross-talk with tumor cells. Tumor-associated macrophages (TAMs) are the major leukocyte population among the tumor-infiltrating immune cells. Once they are infiltrated into tumor stroma they undergo a polarized activation, where the M1 and M2 phenotypes represent the two extreme of the polarization heterogeneity spectrum. It is known that TAMs acquire a specific phenotype (M2), oriented toward tumor growth, angiogenesis and immune-suppression...
August 8, 2018: Cancer Microenvironment: Official Journal of the International Cancer Microenvironment Society
R Ebihara, H Hashimoto, J Kano, T Fujii, S Yoshioka
This paper reports the structural and optical investigations of the structural colour of the weevil Lamprocyphus augustus The photonic crystal structure within the weevil's scales was investigated using sequential focused ion-beam milling and scanning electron microscopy imaging. We carefully analysed the reconstructed three-dimensional structure to determine the unit cell of the photonic crystal. It was found that the cuticle network of the cubic unit cell perfectly matches the previously reported diamond-based network...
August 2018: Journal of the Royal Society, Interface
Svenja Engels, Christoph Daniel Treiber, Marion Claudia Salzer, Andreas Michalik, Lyubov Ushakova, David Anthony Keays, Henrik Mouritsen, Dominik Heyers
Even though previously described iron-containing structures in the upper beak of pigeons were almost certainly macrophages, not magnetosensitive neurons, behavioural and neurobiological evidence still supports the involvement of the ophthalmic branch of the trigeminal nerve (V1) in magnetoreception. In previous behavioural studies, inactivation of putative V1-associated magnetoreceptors involved either application of the surface anaesthetic lidocaine to the upper beak or sectioning of V1. Here, we compared the effects of lidocaine treatment, V1 ablations and sham ablations on magnetic field-driven neuronal activation in V1-recipient brain regions in European robins...
August 2018: Journal of the Royal Society, Interface
Davide Piccinino, Eliana Capecchi, Lorenzo Botta, Bruno Mattia Bizzarri, Paolo Bollella, Riccarda Antiochia, Raffaele Saladino
Microcapsules and nanocapsules based on the contemporary presence of sulfonate lignin and tannic acid have been prepared by the layer-by-layer procedure, using MnCO3 or organosolv lignin as core templates, and polydiallyldimethylammonium chloride or chitosan as positive charged supporting layers. Nanocapsules and microcapsules of mixed polyphenols showed antioxidant activity, UV-shielding properties, and electrochemical responsiveness, higher than that in homo-polymer nanocapsules counterparts and of the native polyphenols, suggesting the presence of synergistic effects between the two components...
August 8, 2018: Biomacromolecules
Yuki Wakisaka, Daiki Kido, Hiromitsu Uehara, Qiuyi Yuan, Felix E Feiten, Shingo Mukai, Satoru Takakusagi, Yohei Uemura, Toshihiko Yokoyama, Takahiro Wada, Motohiro Uo, Oki Sekizawa, Tomoya Uruga, Yasuhiro Iwasawa, Kiyotaka Asakura
Surface fluorescence X-ray absorption fine structure (XAFS) spectroscopy using a Laue-type monochromator has been developed to acquire structural information about metals with a very low concentrate on a flat highly oriented pyrolytic graphite (HOPG) surface in the presence of electrolytes. Generally, surface fluorescence XAFS spectroscopy is hindered by strong scattering from the bulk, which often chokes the pulse counting detector. In this work, we show that a bent crystal Laue analyzer (BCLA) can efficiently remove the scattered X-rays from the bulk even in the presence of solution...
August 8, 2018: Chemical Record: An Official Publication of the Chemical Society of Japan ... [et Al.]
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