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Ali Akbar, Muhammad Waleed Khalid, Muhammad Sabieh Anwar
Magnetic linear birefringence and dichroism are investigated for the paramagnetic terbium gallium garnet (TGG) single crystal in the temperature range 8-100 K. The reciprocal nature is confirmed for the linear birefringence. Furthermore a theoretical model is validated that describes the intermixing of linear and circular birefringence. The ellipticity and rotation of the polarization ellipse are investigated in the light of these measurements. These otherwise minuscule magnetically induced effects are amplified at cryogenic temperatures and are determined by a phase-sensitive technique based on the Fourier decomposition of detected signal intensities...
November 27, 2017: Optics Express
Yicheng Shi, Janet Zheng Jie Lim, Hou Shun Poh, Peng Kian Tan, Peiyu Amelia Tan, Alexander Ling, Christian Kurtsiefer
Quantum key distribution (QKD) at telecom wavelengths (1260 - 1625 nm) has the potential for fast deployment due to existing optical fibre infrastructure and mature telecom technologies. At these wavelengths, Indium Gallium Arsenide (InGaAs) avalanche photodiode (APD) based detectors are the preferred choice for photon detection. Similar to their Silicon counterparts used at shorter wavelengths, they exhibit fluorescence from recombination of electron-hole pairs generated in the avalanche breakdown process...
November 27, 2017: Optics Express
Ran Ditcovski, Tal Ellenbogen
We use numerical simulations to study the effects of nanowire geometry on the emission spectra of nanowire-based lasers. The studied nanowire lasers are made from gallium-nitride and the simulations are performed using finite difference time domain method. We show that changes in the diameter of the nanowire lasers also change the effective refractive index of their optical guided modes, which allows control over their Fabry-Perot spectrum. In addition, we show that evanescent coupling of two vertically standing nanowire lasers, having different cross section sizes, leads to a Vernier effect, which results in single mode emission from the small footprint coupled lasers system...
November 27, 2017: Optics Express
Collin B Eaker, David C Hight, John D O'Regan, Michael D Dickey, Karen E Daniels
We identify and characterize a new class of fingering instabilities in liquid metals; these instabilities are unexpected due to the large interfacial tension of metals. Electrochemical oxidation lowers the effective interfacial tension of a gallium-based liquid metal alloy to values approaching zero, thereby inducing drastic shape changes, including the formation of fractals. The measured fractal dimension (D=1.3±0.05) places the instability in a different universality class than other fingering instabilities...
October 27, 2017: Physical Review Letters
Zachary J Farrell, Christopher Tabor
Eutectic gallium-indium alloy (EGaIn, a room-temperature liquid metal) nanoparticles are of interest for their unique potential uses in self-healing and flexible electronic devices. One reason for their interest is due to a passivating oxide skin that develops spontaneously on exposure to ambient atmosphere which resists deformation and rupture of the resultant liquid particles. It is then of interest to develop methods for control of this oxide growth process. It is hypothesized here that functionalization of EGaIn nanoparticles with thiolated molecules could moderate oxide growth based on insights from the Cabrera-Mott oxidation model...
December 7, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Zhongmei Han, Marko Vehkamäki, Emma Salmi, Markku Leskela, Mikko Ritala
We demonstrate the preparation and exploitation of multilayer metal oxide hard masks for lithography and 3D nanofabrication. Atomic layer deposition (ALD) and focused ion beam (FIB) technologies are applied for mask deposition and mask patterning, respectively. A combination of ALD and FIB was used and a patterning procedure was developed to avoid the ion beam defects commonly met when using FIB alone for microfabrication. ALD grown Al2O3/Ta2O5/Al2O3 thin film stacks were FIB milled with 30 keV gallium ions and chemically etched in 5% tetramethylammonium hydroxide (TMAH) at 50 ℃...
December 7, 2017: Nanotechnology
Kehao Zhang, Bhakti Jariwala, Jun Li, Natalie C Briggs, Baoming Wang, Dmitry Ruzmetov, Robert A Burke, Jordan O Lerach, Tony G Ivanov, Md Haque, Randall M Feenstra, Joshua A Robinson
Two and three-dimensional (2D/3D) hybrid materials have the potential to advance communication and sensing technologies by enabling new or improved device functionality. To date, most 2D/3D hybrid devices utilize mechanical exfoliation or post-synthesis transfer, which can be fundamentally different from directly synthesized layers that are compatible with large scale industrial needs. Therefore, understanding the process/property relationship of synthetic heterostructures is priority for industrially relevant material architectures...
December 7, 2017: Nanoscale
Seray Kaya, Mark Cresswell, Aldo R Boccaccini
Bioactive glasses (BGs) are being used in several biomedical applications, one of them being as antibacterial materials. BGs can be produced via melt-quenching technique or sol-gel method. Bactericidal silver-doped sol-gel derived mesoporous silica-based bioactive glasses were reported for the first time in 2000, having the composition 76SiO2-19CaO-2P2O5-3Ag2O (wt%) and a mean pore diameter of 28nm. This review paper discusses studies carried out exploring the potential antibacterial applications of drug-free mesoporous silica-based BGs...
February 1, 2018: Materials Science & Engineering. C, Materials for Biological Applications
Sky Paderick, Matthew Kessler, Tyler J Hurlburt, Steven M Hughes
Silver gallium sulfide nanocrystals were synthesized and characterized by fluorescence, TEM, EDS, and XRD to better understand the material system with an ideal band gap of 2.7 eV. The crystals were found to nucleate in the monoclinic structure, and develop two fluorescence peaks (650, 460 nm) influenced by stoichiometry.
December 5, 2017: Chemical Communications: Chem Comm
Peter J Wellmann
Power electronics belongs to the future key technologies in order to increase system efficiency as well as performance in automotive and energy saving applications. Silicon is the major material for electronic switches since decades. Advanced fabrication processes and sophisticated electronic device designs have optimized the silicon electronic device performance almost to their theoretical limit. Therefore, to increase the system performance, new materials that exhibit physical and chemical properties beyond silicon need to be explored...
November 17, 2017: Zeitschrift Für Anorganische und Allgemeine Chemie
Kevin R Bagnall, Elizabeth A Moore, Stefan C Badescu, Lenan Zhang, Evelyn N Wang
As semiconductor devices based on silicon reach their intrinsic material limits, compound semiconductors, such as gallium nitride (GaN), are gaining increasing interest for high performance, solid-state transistor applications. Unfortunately, higher voltage, current, and/or power levels in GaN high electron mobility transistors (HEMTs) often result in elevated device temperatures, degraded performance, and shorter lifetimes. Although micro-Raman spectroscopy has become one of the most popular techniques for measuring localized temperature rise in GaN HEMTs for reliability assessment, decoupling the effects of temperature, mechanical stress, and electric field on the optical phonon frequencies measured by micro-Raman spectroscopy is challenging...
November 2017: Review of Scientific Instruments
Ruth A Miller, Brett A Cruden, Ramon Martinez, Debbie G Senesky
Gallium nitride (GaN)-on-sapphire photodetectors are used to measure the ultraviolet (UV) radiance behind a shock wave in support of atmospheric entry sensing technologies. DC spectral response characterization of the GaN-based photodetectors shows a peak response around 365 nm with an UV/visible rejection of an order of magnitude. To conduct in situ measurements of UV shock-layer radiation, the GaN-based photodetectors were installed, without protective packaging, in the test section of a shock tube. The measured UV radiation, in terms of incident optical power on the photodetectors, is in excellent agreement with average UV radiation measured by the shock tube facility spectrometers...
November 2017: Review of Scientific Instruments
Sijie Yang, Ying Qin, Bin Chen, V Ongun Özçelik, Claire E White, Yuxia Shen, Shengxue Yang, Sefaattin Tongay
Recent studies have shown that tellurium based 2D crystals undergo dramatic structural, physical, and chemical changes under ambient conditions. This not only adversely impacts their much desired properties, but also is a roadblock for their applications. Here, we introduce diazonium molecule functionalization based surface engineering route that greatly enhances their environmental stability without sacrificing their much desired properties. Spectroscopy and microscopy results show that diazonium groups significantly slow down the surface reactions, and consequently gallium telluride (GaTe), zirconium telluride (ZrTe3) and molybdenum ditelluride (MoTe2) gain strong resistance to surface transformation in air or when immersed under water...
December 1, 2017: ACS Applied Materials & Interfaces
Christopher J Palestro, Charito Love
Fever of unknown origin, or FUO, is a challenging condition for patients and clinicians. In up to 50% of cases no diagnosis is established. Patient workup begins with comprehensive history, physical examination and laboratory tests. Radionuclide imaging has been a second-line procedure. Gallium-67 citrate, which accumulates in infection, inflammation, and tumor, was for many years, the radionuclide test of choice in the workup of FUO. The 24-72 hours between injection and imaging, relatively high radiation dose to patients, and suboptimal image quality are significant disadvantages; imaging results are variable...
November 29, 2017: Current Pharmaceutical Design
Arturo Loaiza-Bonilla, Paula A Bonilla-Reyes
This manuscript reports on a patient with a metastatic gastrointestinal stromal tumor (GIST) refractory to standard first-line treatment, who underwent a gallium-68 scan based on pre-clinical data of somatostatin receptor (SSTR) expression in such tumors. The gallium-68 DOTATATE scan determined significant somatostatin receptor avidity as hypothesized, suggesting that this imaging modality may be used as an option for diagnostic and follow-up purposes in GIST patients. In addition, peptide receptor-mediated radiotherapy (177Lu-PPRT) via SSTR may provide a novel treatment strategy in carefully selected SSTR-avid GIST patients with thyrosine kinase inhibitor (TKI)-resistant tumors such as this case, and this warrants further investigation in novel clinical trial concepts...
September 24, 2017: Curēus
Kuo-Tang Liao, Joshua Schumacher, Henri J Lezec, Samuel M Stavis
The vertical dimensions of complex nanostructures determine the functions of diverse nanotechnologies. In this paper, we investigate the unknown limits of such structure-function relationships at subnanometer scales. We begin with a quantitative evaluation of measurement uncertainty from atomic force microscopy, which propagates through our investigation from ion beam fabrication to fluorescent particle characterization. We use a focused beam of gallium ions to subtractively pattern silicon surfaces, and silicon nitride and silicon dioxide films...
November 29, 2017: Lab on a Chip
Taichi Nakamura, Katsunori Suzuki, Makoto Yamashita
An anionic indabenzene was synthesized via the transmetallation of an aluminacyclohexadiene with bulky silyl substituents, and fully characterized using multinuclear NMR spectroscopy and X-ray crystallography. The observed structural features are consistent with the formal criteria of aromaticity. Additionally, the results of DFT calculations suggested contributions from an ambiphilic resonance structure, similar to the corresponding aluminum and gallium derivatives.
November 29, 2017: Chemical Communications: Chem Comm
Ichiro Ogura, Takaaki Oda, Mikiko Sue, Yoshihiko Sasaki, Kazuhide Hayama
OBJECTIVE: To assess the gallium-67 (67Ga) scintigraphy in differential diagnosis of malignant tumours from non-tumorous lesions of the maxilla. METHODS: Nineteen patients with malignant tumours (six cases of squamous cell carcinoma and one case of malignant melanoma) and non-tumorous lesions (seven cases of maxillary sinusitis and five cases of postoperative maxillary changes) in the maxilla underwent 67Ga and bone scintigraphy with CT and MRI. The statistical analysis with respect to comparison between imaging features of 67Ga and bone scintigraphy and maxillary lesions was performed with the Pearson's chi-squared test...
2017: Chinese Journal of Dental Research
Thomas W Price, Juan Gallo, Vojtěch Kubíček, Zuzana Böhmová, Timothy J Prior, John Greenman, Petr Hermann, Graeme J Stasiuk
Gallium-68 (68Ga) has been the subject of increasing interest for its potential in the production of radiotracers for diagnosis of diseases. In this work we report the complexation of 68Ga by the amino acid based tripodal chelate H3Dpaa, and two bifunctional derivatives, H3Dpaa.dab and, under a range of conditions with particular emphasis on the rapid complexation of 68Ga at pH 7.4. 100 μM H3Dpaa achieved a radiochemical yield of 95% at pH 7.4 in 5 minutes at 37 °C. The bifunctional derivatives H4Dpaa...
November 27, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Mohsen Cheki, Hariprasad Gali
OBJECTIVE: In this study, we tried to estimate human absorbed dose of 68Ga-NODAGA-glycine as a new potential positron emission tomography (PET) renal agent based on the biodistribution data reported in healthy rats, and compare our estimation with the available absorbed dose data from technetium-99m-diethylenetriaminepentaacetic acid (99mTc-DTPA). SUBJECTS AND METHODS: The medical internal radiation dose (MIRD) formulation was applied to extrapolate from rats to human and to project the absorbed radiation dose for various organs in humans...
November 27, 2017: Hellenic Journal of Nuclear Medicine
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