Ultrasensitive, Biocompatible, Self-Calibrating, Multiparametric Temperature Sensors.

PubMed

Zhao, Haiguang; Vomiero, Alberto; Rosei, Federico

2015-11-18

Core-shell quantum dots serve as self-calibrating, ultrasensitive, multiparametric, near-infrared, and biocompatible temperature sensors. They allow temperature measurement with nanometer accuracy in the range 150-373 K, the broadest ever recorded for a nanothermometer, with sensitivities among the highest ever reported, which makes them essentially unique in the panorama of biocompatible nanothermometers with potential for in vivo biological thermal imaging and/or thermoablative therapy. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Towards Silk Fiber Optics: Refractive Index Characterization, Fiber Spinning, and Spinneret Analysis

NASA Astrophysics Data System (ADS)

Spitzberg, Joshua David

Of the many biologically derived materials, whose historical record of use by humans underscores an ex-vivo utility, silk is interesting for it's contemporary repurposing from textile to biocompatible substrate. And while even within this category silk is one of several materials studied for novel repurposing, it has the unique character of being evolutionarily developed specifically for fiber spinning in vivo. The work discussed here is inspired by taking what nature has given, to explore the in vitro spinning of silk towards biocompatible fiber optics applications. A common formulation of silk used in biomedical studies for re-forming it into the various structures begins with the silkworm cocoon, which is degummed and dissolved into an aqueous solution of its miscible protein, fibroin, and post-treated to fabricate solid structures. In the first aim, the optical refractive index (RI) of various post-treatment methods is discussed towards determining RI design techniques. The methods considered in this work for re-forming a solid fiber from the reconstituted silk fibroin (RSF) solution borrow from the industrial techniques of gel spinning, and dry-spinning. In the second aim, methods are applied to RSF and quality of the spun fibers discussed. A feature common to spinning techniques is passing the (silk) material through a spinneret of specific shape. In the third aim, fluid flow through a simplified native silkworm spinneret is modeled towards bio-inspired lessons in design. In chapter 1 the history, reconstitution, are discussed towards understanding the fabrication of several optical device examples. Chapter 2 then prefaces the experiments and measurements in fiber optics by reviewing electromagnetic theory of waveguide function, and loss factors, to be considered in actual device fabrication. Chapter 3 presents results and discussion for the first aim, understanding design principles for the refractive index of RSF. From this point, industrial fiber-spinning approaches are reviewed from a theoretical and methodological perspective in chapter 4. Thus, chapter 5 presents results for the second aim, efforts to apply these techniques using RSF. Chapter 6 discusses the third aim, understanding the design of the silkworm spinneret by an idealized model of natural and reconstituted silk fibroin flow. While the ultimate goal of a structurally and optically smooth and uniform fiber remains elusive, this work serves as a guide for future efforts.

Facile Fabrication and Characterization of a PDMS-Derived Candle Soot Coated Stable Biocompatible Superhydrophobic and Superhemophobic Surface.

PubMed

Iqbal, R; Majhy, B; Sen, A K

2017-09-13

We report a simple, inexpensive, rapid, and one-step method for the fabrication of a stable and biocompatible superhydrophobic and superhemophobic surface. The proposed surface comprises candle soot particles embedded in a mixture of PDMS+n-hexane serving as the base material. The mechanism responsible for the superhydrophobic behavior of the surface is explained, and the surface is characterized based on its morphology and elemental composition, wetting properties, mechanical and chemical stability, and biocompatibility. The effect of %n-hexane in PDMS, the thickness of the PDMS+n-hexane layer (in terms of spin coating speed) and sooting time on the wetting property of the surface is studied. The proposed surface exhibits nanoscale surface asperities (average roughness of 187 nm), chemical compositions of soot particles, very high water and blood repellency along with excellent mechanical and chemical stability and excellent biocompatibility against blood sample and biological cells. The water contact angle and roll-off angle is measured as 160° ± 1° and 2°, respectively, and the blood contact angle is found to be 154° ± 1°, which indicates that the surface is superhydrophobic and superhemophobic. The proposed superhydrophobic and superhemophobic surface offers significantly improved (>40%) cell viability as compared to glass and PDMS surfaces.

Impact of Surface Functionalization on the Quantum Coherence of Nitrogen-Vacancy Centers in Nanodiamonds.

PubMed

Ryan, Robert G; Stacey, Alastair; O'Donnell, Kane M; Ohshima, Takeshi; Johnson, Brett C; Hollenberg, Lloyd C L; Mulvaney, Paul; Simpson, David A

2018-04-18

Nanoscale quantum probes such as the nitrogen-vacancy (NV) center in diamonds have demonstrated remarkable sensing capabilities over the past decade as control over fabrication and manipulation of these systems has evolved. The biocompatibility and rich surface chemistry of diamonds has added to the utility of these probes but, as the size of these nanoscale systems is reduced, the surface chemistry of diamond begins to impact the quantum properties of the NV center. In this work, we systematically study the effect of the diamond surface chemistry on the quantum coherence of the NV center in nanodiamonds (NDs) 50 nm in size. Our results show that a borane-reduced diamond surface can on average double the spin relaxation time of individual NV centers in nanodiamonds when compared to thermally oxidized surfaces. Using a combination of infrared and X-ray absorption spectroscopy techniques, we correlate the changes in quantum relaxation rates with the conversion of sp 2 carbon to C-O and C-H bonds on the diamond surface. These findings implicate double-bonded carbon species as a dominant source of spin noise for near surface NV centers. The link between the surface chemistry and quantum coherence indicates that through tailored engineering of the surface, the quantum properties and magnetic sensitivity of these nanoscale systems may approach that observed in bulk diamond.

Sensitivity optimization of Bell-Bloom magnetometers by manipulation of atomic spin synchronization

NASA Astrophysics Data System (ADS)

Ranjbaran, M.; Tehranchi, M. M.; Hamidi, S. M.; Khalkhali, S. M. H.

2018-05-01

Many efforts have been devoted to the developments of atomic magnetometers for achieving the high sensitivity required in biomagnetic applications. To reach the high sensitivity, many types of atomic magnetometers have been introduced for optimization of the creation and relaxation rates of atomic spin polarization. In this paper, regards to sensitivity optimization techniques in the Mx configuration, we have proposed a novelty approach for synchronization of the spin precession in the Bell-Bloom magnetometers. We have utilized the phenomenological Bloch equations to simulate the spin dynamics when modulation of pumping light and radio frequency magnetic field were both used for atomic spin synchronization. Our results showed that the synchronization process, improved the magnetometer sensitivity respect to the classical configurations.

Biofabrication of a PLGA-TCP-based porous bioactive bone substitute with sustained release of icaritin.

PubMed

Xie, Xin-Hui; Wang, Xin-Luan; Zhang, Ge; He, Yi-Xin; Leng, Yang; Tang, Ting-Ting; Pan, Xiaohua; Qin, Ling

2015-08-01

A phytomolecule, icaritin, has been identified and shown to be osteopromotive for the prevention of osteoporosis and osteonecrosis. This study aimed to produce a bioactive poly (l-lactide-co-glycolide)-tricalcium phosphate (PLGA-TCP)-based porous scaffold incorporating the osteopromotive phytomolecule icaritin, using a fine spinning technology. Both the structure and the composition of icaritin-releasing PLGA-TCP-based scaffolds were evaluated by scanning electron microscopy (SEM). The porosity was quantified by both water absorption and micro-computed tomography (micro-CT). The mechanical properties were evaluated using a compression test. In vitro release of icaritin from the PLGA-TCP scaffold was quantified by high-performance liquid chromatography (HPLC). The attachment, proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) on the composite scaffold were evaluated. Both an in vitro cytotoxicity test and an in vivo test via muscular implantation were conducted to confirm the scaffold's biocompatibility. The results showed that the PLGA-TCP-icaritin composite scaffold was porous, with interconnected macro- (about 480 µm) and micropores (2-15 µm). The mechanical properties of the PLGA-TCP-icaritin scaffold were comparable with those of the pure PLGA-TCP scaffold, yet was spinning direction-dependent. Icaritin content was detected in the medium and increased with time. The PLGA-TCP-icaritin scaffold facilitated the attachment, proliferation and osteogenic differentiation of BMSCs. In vitro cytotoxicity test and in vivo intramuscular implantation showed that the composite scaffold had no toxicity with good biocompatibility. In conclusion, an osteopromotive phytomolecule, icaritin, was successfully incorporated into PLGA-TCP to form an innovative porous composite scaffold with sustained release of osteopromotive icaritin, and this scaffold had good biocompatibility and osteopromotion, suggesting its potential for orthopaedic applications. Copyright © 2012 John Wiley & Sons, Ltd.

Unifying Exchange Sensitivity in Transition-Metal Spin-State Ordering and Catalysis through Bond Valence Metrics.

PubMed

Gani, Terry Z H; Kulik, Heather J

2017-11-14

Accurate predictions of spin-state ordering, reaction energetics, and barrier heights are critical for the computational discovery of open-shell transition-metal (TM) catalysts. Semilocal approximations in density functional theory, such as the generalized gradient approximation (GGA), suffer from delocalization error that causes them to overstabilize strongly bonded states. Descriptions of energetics and bonding are often improved by introducing a fraction of exact exchange (e.g., erroneous low-spin GGA ground states are instead correctly predicted as high-spin with a hybrid functional). The degree of spin-splitting sensitivity to exchange can be understood based on the chemical composition of the complex, but the effect of exchange on reaction energetics within a single spin state is less well-established. Across a number of model iron complexes, we observe strong exchange sensitivities of reaction barriers and energies that are of the same magnitude as those for spin splitting energies. We rationalize trends in both reaction and spin energetics by introducing a measure of delocalization, the bond valence of the metal-ligand bonds in each complex. The bond valence thus represents a simple-to-compute property that unifies understanding of exchange sensitivity for catalytic properties and spin-state ordering in TM complexes. Close agreement of the resulting per-metal-organic-bond sensitivity estimates, together with failure of alternative descriptors demonstrates the utility of the bond valence as a robust descriptor of how differences in metal-ligand delocalization produce differing relative energetics with exchange tuning. Our unified description explains the overall effect of exact exchange tuning on the paradigmatic two-state FeO + /CH 4 reaction that combines challenges of spin-state and reactivity predictions. This new descriptor-sensitivity relationship provides a path to quantifying how predictions in transition-metal complex screening are sensitive to the method used.

Nuclear-Spin Gyroscope Based on an Atomic Co-Magnetometer

NASA Technical Reports Server (NTRS)

Romalis, Michael; Komack, Tom; Ghost, Rajat

2008-01-01

An experimental nuclear-spin gyroscope is based on an alkali-metal/noblegas co-magnetometer, which automatically cancels the effects of magnetic fields. Whereas the performances of prior nuclear-spin gyroscopes are limited by sensitivity to magnetic fields, this gyroscope is insensitive to magnetic fields and to other external perturbations. In addition, relative to prior nuclear-spin gyroscopes, this one exhibits greater sensitivity to rotation. There is commercial interest in development of small, highly sensitive gyroscopes. The present experimental device could be a prototype for development of nuclear spin gyroscopes suitable for navigation. In comparison with fiber-optic gyroscopes, these gyroscopes would draw less power and would be smaller, lighter, more sensitive, and less costly.

Biocompatible and Biomimetic Self-Assembly of Functional

DTIC Science & Technology

2007-10-03

rearrangement of the lipid/silica matrix to create a bio/nano interface quite similar to that formed by direct CDA. This approach has several advantages over CDA...precursors with a biologically compatible surfactant, glycerol monooleate ( GMO ) via dip-coating, spin-coating, drop-casting, or aerosol deposition...with water and remains in a semi-solid state. Upon exposure to UV/ozone, the GMO begins to photodecompose and the silanol precursors become more

Induction-detection electron spin resonance with spin sensitivity of a few tens of spins

DOE Office of Scientific and Technical Information (OSTI.GOV)

Artzi, Yaron; Twig, Ygal; Blank, Aharon

2015-02-23

Electron spin resonance (ESR) is a spectroscopic method that addresses electrons in paramagnetic materials directly through their spin properties. ESR has many applications, ranging from semiconductor characterization to structural biology and even quantum computing. Although it is very powerful and informative, ESR traditionally suffers from low sensitivity, requiring many millions of spins to get a measureable signal with commercial systems using the Faraday induction-detection principle. In view of this disadvantage, significant efforts were made recently to develop alternative detection schemes based, for example, on force, optical, or electrical detection of spins, all of which can reach single electron spin sensitivity.more » This sensitivity, however, comes at the price of limited applicability and usefulness with regard to real scientific and technological issues facing modern ESR which are currently dealt with conventional induction-detection ESR on a daily basis. Here, we present the most sensitive experimental induction-detection ESR setup and results ever recorded that can detect the signal from just a few tens of spins. They were achieved thanks to the development of an ultra-miniature micrometer-sized microwave resonator that was operated at ∼34 GHz at cryogenic temperatures in conjunction with a unique cryogenically cooled low noise amplifier. The test sample used was isotopically enriched phosphorus-doped silicon, which is of significant relevance to spin-based quantum computing. The sensitivity was experimentally verified with the aid of a unique high-resolution ESR imaging approach. These results represent a paradigm shift with respect to the capabilities and possible applications of induction-detection-based ESR spectroscopy and imaging.« less

Spectroscopy on the wing: naturally inspired SERS substrates for biochemical analysis.

PubMed

Garrett, Natalie L; Vukusic, Peter; Ogrin, Feodor; Sirotkin, Evgeny; Winlove, C Peter; Moger, Julian

2009-03-01

We show that naturally occurring chitinous nanostructures found on the wings of the Graphium butterfly can be used as substrates for surface-enhanced Raman scattering when coated with a thin film of gold or silver. The substrates were found to exhibit excellent biocompatibility and sensitivity, making them ideal for protein assaying. An assay using avidin/biotin binding showed that the substrates could be used to quantify protein binding directly from changes in the surface-enhanced Raman scattering (SERS) spectra and were sensitive over a concentration range comparable with a typical enzyme-linked immunosorbent assays (ELISA) assay. A biomimetic version of the wing nanostructures produced using a highly reproducible, large-scale fabrication process, yielded comparable enhancement factors and biocompatibility. The excellent biocompatibility of the wings and biomimetic substrates is unparalleled by other lithographically produced substrates, and this could pave the way for widespread application of ultrasensitive SERS-based bioassays.

Oxygen Sensing with Perfluorocarbon-Loaded Ultraporous Mesostructured Silica Nanoparticles.

PubMed

Lee, Amani L; Gee, Clifford T; Weegman, Bradley P; Einstein, Samuel A; Juelfs, Adam R; Ring, Hattie L; Hurley, Katie R; Egger, Sam M; Swindlehurst, Garrett; Garwood, Michael; Pomerantz, William C K; Haynes, Christy L

2017-06-27

Oxygen homeostasis is important in the regulation of biological function. Disease progression can be monitored by measuring oxygen levels, thus producing information for the design of therapeutic treatments. Noninvasive measurements of tissue oxygenation require the development of tools with minimal adverse effects and facile detection of features of interest. Fluorine magnetic resonance imaging ( 19 F MRI) exploits the intrinsic properties of perfluorocarbon (PFC) liquids for anatomical imaging, cell tracking, and oxygen sensing. However, the highly hydrophobic and lipophobic properties of perfluorocarbons require the formation of emulsions for biological studies, though stabilizing these emulsions has been challenging. To enhance the stability and biological loading of perfluorocarbons, one option is to incorporate perfluorocarbon liquids into the internal space of biocompatible mesoporous silica nanoparticles. Here, we developed perfluorocarbon-loaded ultraporous mesostructured silica nanoparticles (PERFUMNs) as 19 F MRI detectable oxygen-sensing probes. Ultraporous mesostructured silica nanoparticles (UMNs) have large internal cavities (average = 1.8 cm 3 g -1 ), facilitating an average 17% loading efficiency of PFCs, meeting the threshold fluorine concentrations needed for imaging studies. Perfluoro-15-crown-5-ether PERFUMNs have the highest equivalent nuclei per PFC molecule and a spin-lattice (T 1 ) relaxation-based oxygen sensitivity of 0.0032 mmHg -1 s -1 at 16.4 T. The option of loading PFCs after synthesizing UMNs, rather than traditional in situ core-shell syntheses, allows for use of a broad range of PFC liquids from a single material. The biocompatible and tunable chemistry of UMNs combined with the intrinsic properties of PFCs makes PERFUMNs a MRI sensor with potential for anatomical imaging, cell tracking, and metabolic spectroscopy with improved stability.

Biocorrosion Evaluation on a Zr-Cu-Ag-Ti Metallic Glass

NASA Astrophysics Data System (ADS)

Kumar, Shresh; Anwar, Rebin; Ryu, Wookha; Park, E. S.; Vincent, S.

2018-04-01

Metallic glasses are in high demand for fabrication of variety of innovative products, in particular surgical and biomedical tools and devices owing to its excellent biocompatible properties. In the present investigation, a novel Zr39.5Cu50.5Ag4Ti6 metallic glass composition was synthesized using melt spinning technique. Potentiodynamic polarization studies were conducted to investigate bio-corrosion behaviour of Zr39.5Cu50.5Ag4Ti6 metallic glass. The test were conducted in various simulated artificial body conditions such as artificial saliva solution, phosphate-buffered saline solution, artificial blood plasma solution, and Hank’s balanced saline solution. The bio-corrosion results of metallic glass were compared with traditional biomaterials. The study aims to provide bio-compatible properties of Zr39.5Cu50.5Ag4Ti6 metallic glass.

Synthesis, characterization and in vivo evaluation of biocompatible ferrogels

NASA Astrophysics Data System (ADS)

Lopez-Lopez, M. T.; Rodriguez, I. A.; Rodriguez-Arco, L.; Carriel, V.; Bonhome-Espinosa, A. B.; Campos, F.; Zubarev, A.; Duran, J. D. G.

2017-06-01

A hydrogel is a 3-D network of polymer chains in which water is the dispersion medium. Hydrogels have found extensive applications in the biomedical field due to their resemblance to living tissues. Furthermore, hydrogels can be endowed with exceptional properties by addition of synthetic materials. For example, magnetic field-sensitive gels, called ferrogels, are obtained by embedding magnetic particles in the polymer network. Novel living tissues with unique magnetic field-sensitive properties were recently prepared by 3-D cell culture in biocompatible ferrogels. This paper critically reviews the most recent progress and perspectives in their synthesis, characterization and biocompatibility evaluation. Optimization of ferrogels for this novel application requires low-density, strongly magnetic, multi-domain particles. Interestingly, the rheological properties of the resulting ferrogels in the absence of field were largely enhanced with respect to nonmagnetic hydrogels, which can only be explained by the additional cross-linking imparted by the embedded magnetic particles. Remarkably, rheological measurements under an applied magnetic field demonstrated that ferrogels presented reversibly tunable mechanical properties, which constitutes a unique advantage with respect to nonmagnetic hydrogels. In vivo evaluation of ferrogels showed good biocompatibility, with only some local inflammatory response, and no particle migration or damage to distant organs.

Method of manufacturing fibrous hemostatic bandages

DOEpatents

Larsen, Gustavo; Spretz, Ruben; Velarde-Ortiz, Raffet

2012-09-04

A method of manufacturing a sturdy and pliable fibrous hemostatic dressing by making fibers that maximally expose surface area per unit weight of active ingredients as a means for aiding in the clot forming process and as a means of minimizing waste of active ingredients. The method uses a rotating object to spin off a liquid biocompatible fiber precursor, which is added at its center. Fibers formed then deposit on a collector located at a distance from the rotating object creating a fiber layer on the collector. An electrical potential difference is maintained between the rotating disk and the collector. Then, a liquid procoagulation species is introduced at the center of the rotating disk such that it spins off the rotating disk and coats the fibers.

Measurement Sensitivity Improvement of All-Optical Atomic Spin Magnetometer by Suppressing Noises

PubMed Central

Chen, Xiyuan; Zhang, Hong; Zou, Sheng

2016-01-01

Quantum manipulation technology and photoelectric detection technology have jointly facilitated the rapid development of ultra-sensitive atomic spin magnetometers. To improve the output signal and sensitivity of the spin-exchange-relaxation-free (SERF) atomic spin magnetometer, the noises influencing on the output signal and the sensitivity were analyzed, and the corresponding noise suppression methods were presented. The magnetic field noises, including the residual magnetic field noise and the light shift noise, were reduced to approximately zero by employing the magnetic field compensation method and by adjusting the frequency of the pump beam, respectively. With respect to the operation temperature, the simulation results showed that the temperature of the potassium atomic spin magnetometer realizing the spin-exchange relaxation-free regime was 180 °C. Moreover, the fluctuation noises of the frequency and the power were suppressed by using the frequency and the power stable systems. The experimental power stability results showed that the light intensity stability was enhanced 10%. Contrast experiments on the sensitivity were carried out to demonstrate the validity of the suppression methods. Finally, a sensitivity of 13 fT/Hz1/2 was successfully achieved by suppressing noises and optimizing parameters. PMID:27322272

Amperometric Biosensors Based on 3-Dimensional Hydrogel-Forming Epoxy Networks

DTIC Science & Technology

1993-05-24

are epoxy- embedded and contained in a 0.3mm diameter biocompatible polyimide tubing. The ensemble of epoxy-embedded fiber tips is coated with the...electrode is then overcoated with a biocompatible film. The electrode’s sensitivity is 2.5xI0 2 A cm’ 2 M 1. It can be stored at 40 C for 4 months with no

Ultra-Bright and -Stable Red and Near-Infrared Squaraine Fluorophores for In Vivo Two-Photon Imaging

PubMed Central

Podgorski, Kaspar; Terpetschnig, Ewald; Klochko, Oleksii P.; Obukhova, Olena M.; Haas, Kurt

2012-01-01

Fluorescent dyes that are bright, stable, small, and biocompatible are needed for high-sensitivity two-photon imaging, but the combination of these traits has been elusive. We identified a class of squaraine derivatives with large two-photon action cross-sections (up to 10,000 GM) at near-infrared wavelengths critical for in vivo imaging. We demonstrate the biocompatibility and stability of a red-emitting squaraine-rotaxane (SeTau-647) by imaging dye-filled neurons in vivo over 5 days, and utility for sensitive subcellular imaging by synthesizing a specific peptide-conjugate label for the synaptic protein PSD-95. PMID:23251670

Antiferromagnetic spin current rectifier

NASA Astrophysics Data System (ADS)

Khymyn, Roman; Tiberkevich, Vasil; Slavin, Andrei

2017-05-01

It is shown theoretically, that an antiferromagnetic dielectric with bi-axial anisotropy, such as NiO, can be used for the rectification of linearly-polarized AC spin current. The AC spin current excites two evanescent modes in the antiferromagnet, which, in turn, create DC spin current flowing back through the antiferromagnetic surface. Spin diode based on this effect can be used in future spintronic devices as direct detector of spin current in the millimeter- and submillimeter-wave bands. The sensitivity of such a spin diode is comparable to the sensitivity of modern electric Schottky diodes and lies in the range 102-103 V/W for 30 ×30 nm2 structure.

Fabrication of polyurethane and polyurethane based composite fibres by the electrospinning technique for soft tissue engineering of cardiovascular system.

PubMed

Kucinska-Lipka, J; Gubanska, I; Janik, H; Sienkiewicz, M

2015-01-01

Electrospinning is a unique technique, which provides forming of polymeric scaffolds for soft tissue engineering, which include tissue scaffolds for soft tissues of the cardiovascular system. Such artificial soft tissues of the cardiovascular system may possess mechanical properties comparable to native vascular tissues. Electrospinning technique gives the opportunity to form fibres with nm- to μm-scale in diameter. The arrangement of obtained fibres and their surface determine the biocompatibility of the scaffolds. Polyurethanes (PUs) are being commonly used as a prosthesis of cardiovascular soft tissues due to their excellent biocompatibility, non-toxicity, elasticity and mechanical properties. PUs also possess fine spinning properties. The combination of a variety of PU properties with an electrospinning technique, conducted at the well tailored conditions, gives unlimited possibilities of forming novel polyurethane materials suitable for soft tissue scaffolds applied in cardiovascular tissue engineering. This paper can help researches to gain more widespread and deeper understanding of designing electrospinable PU materials, which may be used as cardiovascular soft tissue scaffolds. In this paper we focus on reagents used in PU synthesis designed to increase PU biocompatibility (polyols) and biodegradability (isocyanates). We also describe suggested surface modifications of electrospun PUs, and the direct influence of surface wettability on providing enhanced biocompatibility of scaffolds. We indicate a great influence of electrospinning parameters (voltage, flow rate, working distance) and used solvents (mostly DMF, THF and HFIP) on fibre alignment and diameter - what impacts the biocompatibility and hemocompatibility of such electrospun PU scaffolds. Moreover, we present PU modifications with natural polymers with novel approach applied in electrospinning of PU scaffolds. This work may contribute with further developing of novel electrospun PUs, which may be applied as soft tissue scaffolds of the cardiovascular system. Copyright © 2014. Published by Elsevier B.V.

Zinc chlorophyll aggregates as hole transporters for biocompatible, natural-photosynthesis-inspired solar cells

NASA Astrophysics Data System (ADS)

Li, Yue; Sasaki, Shin-ichi; Tamiaki, Hitoshi; Liu, Cheng-Liang; Song, Jiaxing; Tian, Wenjing; Zheng, Enqiang; Wei, Yingjin; Chen, Gang; Fu, Xueqi; Wang, Xiao-Feng

2015-11-01

The intriguing properties of extremely efficient delocalization and migration of excitons in chlorophyll (Chl) J-type aggregates have inspired intense research activities toward their structural understanding, functional interpretation and mimicry synthesis. Herein, we demonstrated the J-aggregates of zinc methyl 3-devinyl-3-hydroxymethyl-pyropheophorbide a (ZnChl-1) generated by spin-coating method for the application as a hole transporter in titania-based solar cells using methyl trans-32-carboxypyropheophorbide a (H2Chl-2) or its zinc complex (ZnChl-2) as the sensitizer. The effective carrier mobility of the J-aggregates films was determined by the organic field-effect transistor to be 6.2 × 10-4 cm2 V-1 s-1. Solar cells sharing the architecture of FTO/H2Chl-2 or ZnChl-2 on TiO2/(ZnChl-1)n/Ag were fabricated and the factors that presumably determine their photovoltaic performances were discussed. The photovoltaic devices studied herein employing inexpensive and pollution-free biomaterials provide a unique solution of utilizing solar energy with a care of the important environmental issue.

Giant spin-torque diode sensitivity in the absence of bias magnetic field.

PubMed

Fang, Bin; Carpentieri, Mario; Hao, Xiaojie; Jiang, Hongwen; Katine, Jordan A; Krivorotov, Ilya N; Ocker, Berthold; Langer, Juergen; Wang, Kang L; Zhang, Baoshun; Azzerboni, Bruno; Amiri, Pedram Khalili; Finocchio, Giovanni; Zeng, Zhongming

2016-04-07

Microwave detectors based on the spin-torque diode effect are among the key emerging spintronic devices. By utilizing the spin of electrons in addition to charge, they have the potential to overcome the theoretical performance limits of their semiconductor (Schottky) counterparts. However, so far, practical implementations of spin-diode microwave detectors have been limited by the necessity to apply a magnetic field. Here, we demonstrate nanoscale magnetic tunnel junction microwave detectors, exhibiting high-detection sensitivity of 75,400 mV mW(-1) at room temperature without any external bias fields, and for low-input power (micro-Watts or lower). This sensitivity is significantly larger than both state-of-the-art Schottky diode detectors and existing spintronic diodes. Micromagnetic simulations and measurements reveal the essential role of injection locking to achieve this sensitivity performance. This mechanism may provide a pathway to enable further performance improvement of spin-torque diode microwave detectors.

Giant spin-torque diode sensitivity in the absence of bias magnetic field

PubMed Central

Fang, Bin; Carpentieri, Mario; Hao, Xiaojie; Jiang, Hongwen; Katine, Jordan A.; Krivorotov, Ilya N.; Ocker, Berthold; Langer, Juergen; Wang, Kang L.; Zhang, Baoshun; Azzerboni, Bruno; Amiri, Pedram Khalili; Finocchio, Giovanni; Zeng, Zhongming

2016-01-01

Microwave detectors based on the spin-torque diode effect are among the key emerging spintronic devices. By utilizing the spin of electrons in addition to charge, they have the potential to overcome the theoretical performance limits of their semiconductor (Schottky) counterparts. However, so far, practical implementations of spin-diode microwave detectors have been limited by the necessity to apply a magnetic field. Here, we demonstrate nanoscale magnetic tunnel junction microwave detectors, exhibiting high-detection sensitivity of 75,400 mV mW−1 at room temperature without any external bias fields, and for low-input power (micro-Watts or lower). This sensitivity is significantly larger than both state-of-the-art Schottky diode detectors and existing spintronic diodes. Micromagnetic simulations and measurements reveal the essential role of injection locking to achieve this sensitivity performance. This mechanism may provide a pathway to enable further performance improvement of spin-torque diode microwave detectors. PMID:27052973

Magnetic field sensors using 13-spin cat states

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simmons, Stephanie; Karlen, Steven D.; Jones, Jonathan A.

2010-08-15

Measurement devices could benefit from entangled correlations to yield a measurement sensitivity approaching the physical Heisenberg limit. Building upon previous magnetometric work using pseudoentangled spin states in solution-state NMR, we present two conceptual advancements to better prepare and interpret the pseudoentanglement resource. We apply these to a 13-spin cat state to measure the local magnetic field with a 12.2 sensitivity increase over an equivalent number of isolated spins.

Firefly Luciferin-Inspired Biocompatible Chemistry for Protein Labeling and In Vivo Imaging.

PubMed

Wang, Yuqi; An, Ruibing; Luo, Zhiliang; Ye, Deju

2018-04-17

Biocompatible reactions have emerged as versatile tools to build various molecular imaging probes that hold great promise for the detection of biological processes in vitro and/or in vivo. In this Minireview, we describe the recent advances in the development of a firefly luciferin-inspired biocompatible reaction between cyanobenzothiazole (CBT) and cysteine (Cys), and highlight its versatility to label proteins and build multimodality molecular imaging probes. The review starts from the general introduction of biocompatible reactions, which is followed by briefly describing the development of the firefly luciferin-inspired biocompatible chemistry. We then discuss its applications for the specific protein labeling and for the development of multimodality imaging probes (fluorescence, bioluminescence, MRI, PET, photoacoustic, etc.) that enable high sensitivity and spatial resolution imaging of redox environment, furin and caspase-3/7 activity in living cells and mice. Finally, we offer the conclusions and our perspective on the various and potential applications of this reaction. We hope that this review will contribute to the research of biocompatible reactions for their versatile applications in protein labeling and molecular imaging. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Introducing biomimetic shear and ion gradients to microfluidic spinning improves silk fiber strength.

PubMed

Li, David; Jacobsen, Matthew M; Gyune Rim, Nae; Backman, Daniel; Kaplan, David L; Wong, Joyce Y

2017-05-31

Silkworm silk is an attractive biopolymer for biomedical applications due to its high mechanical strength and biocompatibility; as a result, there is increasing interest in scalable devices to spin silk and recombinant silk so as to improve and customize their properties for diverse biomedical purposes (Vepari and Kaplan 2007 Prog. Polym. Sci. 32 ). While artificial spinning of regenerated silk fibroins adds tunability to properties such as degradation rate and surface functionalization, the resulting fibers do not yet approach the mechanical strength of native silkworm silk. These drawbacks reduce the applicability and attractiveness of artificial silk (Kinahan et al 2011 Biomacromolecules 12 ). Here, we used computational fluid dynamic simulations to incorporate shear in tandem with biomimetic ion gradients by coupling a modular novel glass microfluidic device to our previous co-axial flow device. Fibers spun with this combined apparatus demonstrated a significant increase in mechanical strength compared to fibers spun with the basic apparatus alone, with a three-fold increase in Young's modulus and extensibility and a twelve-fold increase in toughness. These results thus demonstrate the critical importance of ionic milieu and shear stress in spinning strong fibers from solubilized silk fibroin.

Control of electron spin and orbital resonances in quantum dots through spin-orbit interactions

NASA Astrophysics Data System (ADS)

Stano, Peter; Fabian, Jaroslav

2008-01-01

The influence of a resonant oscillating electromagnetic field on a single electron in coupled lateral quantum dots in the presence of phonon-induced relaxation and decoherence is investigated. Using symmetry arguments, it is shown that the spin and orbital resonances can be efficiently controlled by spin-orbit interactions. The control is possible due to the strong sensitivity of the Rabi frequency to the dot configuration (the orientation of the dot and the applied static magnetic field); the sensitivity is a result of the anisotropy of the spin-orbit interactions. The so-called easy passage configuration is shown to be particularly suitable for a magnetic manipulation of spin qubits, ensuring long spin relaxation times and protecting the spin qubits from electric field disturbances accompanying on-chip manipulations.

Biocompatibility of nanostructured boron doped diamond for the attachment and proliferation of human neural stem cells.

PubMed

Taylor, Alice C; Vagaska, Barbora; Edgington, Robert; Hébert, Clément; Ferretti, Patrizia; Bergonzo, Philippe; Jackman, Richard B

2015-12-01

We quantitatively investigate the biocompatibility of chemical vapour deposited (CVD) nanocrystalline diamond (NCD) after the inclusion of boron, with and without nanostructuring. The nanostructuring method involves a novel approach of growing NCD over carbon nanotubes (CNTs) that act as a 3D scaffold. This nanostructuring of BNCD leads to a material with increased capacitance, and this along with wide electrochemical window makes BNCD an ideal material for neural interface applications, and thus it is essential that their biocompatibility is investigated. Biocompatibility was assessed by observing the interaction of human neural stem cells (hNSCs) with a variety of NCD substrates including un-doped ones, and NCD doped with boron, which are both planar, and nanostructured. hNSCs were chosen due to their sensitivity, and various methods including cell population and confluency were used to quantify biocompatibility. Boron inclusion into NCD film was shown to have no observable effect on hNSC attachment, proliferation and viability. Furthermore, the biocompatibility of nanostructured boron-doped NCD is increased upon nanostructuring, potentially due to the increased surface area. Diamond is an attractive material for supporting the attachment and development of cells as it can show exceptional biocompatibility. When boron is used as a dopant within diamond it becomes a p-type semiconductor, and at high concentrations the diamond becomes quasi-metallic, offering the prospect of a direct electrical device-cell interfacing system.

DNA nanosensor based on biocompatible graphene quantum dots and carbon nanotubes.

PubMed

Qian, Zhao Sheng; Shan, Xiao Yue; Chai, Lu Jing; Ma, Juan Juan; Chen, Jian Rong; Feng, Hui

2014-10-15

An ultrasensitive nanosensor based on fluorescence resonance energy transfer (FRET) between biocompatible graphene quantum dots and carbon nanotubes for DNA detection was reported. We take advantage of good biocompatibility and strong fluorescence of graphene quantum dots, base pairing specificity of DNA and unique fluorescence resonance energy transfer between graphene quantum dots and carbon nanotubes to achieve the analysis of low concentrations of DNA. Graphene quantum dots with high quantum yield up to 0.20 were prepared and served as the fluorophore of DNA probe. FRET process between graphene quantum dots-labeled probe and oxidized carbon nanotubes is easily achieved due to their efficient self-assembly through specific π-π interaction. This nanosensor can distinguish complementary and mismatched nucleic acid sequences with high sensitivity and good reproducibility. The detection method based on this nanosensor possesses a broad linear span of up to 133.0 nM and ultralow detection limit of 0.4 nM. The constructed nanosensor is expected to be highly biocompatible because of all its components with excellent biocompatibility. Copyright © 2014 Elsevier B.V. All rights reserved.

Search for exotic spin-dependent interactions with a spin-exchange relaxation-free magnetometer

DOE PAGES

Chu, Pinghan; Kim, Young Jin; Savukov, Igor Mykhaylovich

2016-08-15

We propose a novel experimental approach to explore exotic spin-dependent interactions using a spin-exchange relaxation-free (SERF) magnetometer, the most sensitive noncryogenic magnetic-field sensor. This approach studies the interactions between optically polarized electron spins located inside a vapor cell of the SERF magnetometer and unpolarized or polarized particles of external solid-state objects. The coupling of spin-dependent interactions to the polarized electron spins of the magnetometer induces the tilt of the electron spins, which can be detected with high sensitivity by a probe laser beam similarly as an external magnetic field. Lastly, we estimate that by moving unpolarized or polarized objects nextmore » to the SERF Rb vapor cell, the experimental limit to the spin-dependent interactions can be significantly improved over existing experiments, and new limits on the coupling strengths can be set in the interaction range below 10 –2 m.« less

High-efficiency resonant amplification of weak magnetic fields for single spin magnetometry at room temperature.

PubMed

Trifunovic, Luka; Pedrocchi, Fabio L; Hoffman, Silas; Maletinsky, Patrick; Yacoby, Amir; Loss, Daniel

2015-06-01

Magnetic resonance techniques not only provide powerful imaging tools that have revolutionized medicine, but they have a wide spectrum of applications in other fields of science such as biology, chemistry, neuroscience and physics. However, current state-of-the-art magnetometers are unable to detect a single nuclear spin unless the tip-to-sample separation is made sufficiently small. Here, we demonstrate theoretically that by placing a ferromagnetic particle between a nitrogen-vacancy magnetometer and a target spin, the magnetometer sensitivity is improved dramatically. Using materials and techniques that are already experimentally available, our proposed set-up is sensitive enough to detect a single nuclear spin within ten milliseconds of data acquisition at room temperature. The sensitivity is practically unchanged when the ferromagnet surface to the target spin separation is smaller than the ferromagnet lateral dimensions; typically about a tenth of a micrometre. This scheme further benefits when used for nitrogen-vacancy ensemble measurements, enhancing sensitivity by an additional three orders of magnitude.

Innovative micro-textured hydroxyapatite and poly(l-lactic)-acid polymer composite film as a flexible, corrosion resistant, biocompatible, and bioactive coating for Mg implants.

PubMed

Kim, Sae-Mi; Kang, Min-Ho; Kim, Hyoun-Ee; Lim, Ho-Kyung; Byun, Soo-Hwan; Lee, Jong-Ho; Lee, Sung-Mi

2017-12-01

The utility of a novel ceramic/polymer-composite coating with a micro-textured microstructure that would significantly enhance the functions of biodegradable Mg implants is demonstrated here. To accomplish this, bioactive hydroxyapatite (HA) micro-dots can be created by immersing a Mg implant with a micro-patterned photoresist surface in an aqueous solution containing calcium and phosphate ions. The HA micro-dots can then be surrounded by a flexible poly(l-lactic)-acid (PLLA) polymer using spin coating to form a HA/PLLA micro-textured coating layer. The HA/PLLA micro-textured coating layer showed an excellent corrosion resistance when it was immersed in a simulated body fluid (SBF) solution and good biocompatibility, which was assessed by in vitro cell tests. In addition, the HA/PLLA micro-textured coating layer had high deformation ability, where no apparent changes in the coating layer were observed even after a 5% elongation, which would be unobtainable using HA and PLLA coating layers; furthermore, this allowed the mechanically-strained Mg implant with the HA/PLLA micro-textured coating layer to preserve its excellent corrosion resistance and biocompatibility in vitro. Copyright © 2017 Elsevier B.V. All rights reserved.

Biocompatible Nb2O5 thin films prepared by means of the sol-gel process.

PubMed

Velten, D; Eisenbarth, E; Schanne, N; Breme, J

2004-04-01

Thin biocompatible oxide films with an optimised composition and structure on the surface of titanium and its alloys can improve the implant integration. The preparation of these thin oxide layers with the intended improvement of the surface properties can be realised by means of the sol-gel process. Nb2O5 is a promising coating material for this application because of its extremely high corrosion resistance and thermodynamic stability. In this study, thin Nb2O5 layers ( < 200 nm) were prepared by spin coating of polished discs of cp-titanium with a sol consisting of a mixture of niobium ethoxide, butanol and acetylacetone. The thickness, phase composition, corrosion resistance and the wettability of the oxide layers were determined after an optimisation of the processing parameters for deposition of oxide without any organic impurities. The purity of the oxide layer is an important aspect in order to avoid a negative response to the cell adhesion. The biocompatibility of the oxide layers which was investigated by in vitro tests (morphology, proliferation rate, WST-1, cell spreading) is improved as compared to uncoated and TiO2 sol-gel coated cp-titanium concerning the spreading of cells, collagen I synthesis and wettability.

A Magnetoresistive Tactile Sensor for Harsh Environment Applications

PubMed Central

Alfadhel, Ahmed; Khan, Mohammed Asadullah; Cardoso, Susana; Leitao, Diana; Kosel, Jürgen

2016-01-01

A magnetoresistive tactile sensor is reported, which is capable of working in high temperatures up to 140 °C. Hair-like bioinspired structures, known as cilia, made out of permanent magnetic nanocomposite material on top of spin-valve giant magnetoresistive (GMR) sensors are used for tactile sensing at high temperatures. The magnetic nanocomposite, consisting of iron nanowires incorporated into the polymer polydimethylsiloxane (PDMS), is very flexible, biocompatible, has high remanence, and is also resilient to antagonistic sensing ambient. When the cilia come in contact with a surface, they deflect in compliance with the surface topology. This yields a change of the GMR sensor signal, enabling the detection of extremely fine features. The spin-valve is covered with a passivation layer, which enables adequate performance in spite of harsh environmental conditions, as demonstrated in this paper for high temperature. PMID:27164113

Synthesis of a chitosan-based photo-sensitive hydrogel and its biocompatibility and biodegradability.

PubMed

He, Ming; Han, Baoqin; Jiang, Zhiwen; Yang, Yan; Peng, Yanfei; Liu, Wanshun

2017-06-15

Hydroxyethyl chitosan (HECTS) is one of the most important water soluble derivatives of chitosan. In this study, photo-sensitive azidehydroxyethyl chitosan (AZ-HECTS) was synthesized with grafting degree 3.4%, and its water solution resulted in an insoluble hydrogel by 254nm UV irradiation for 90s. AZ-HECTS hydrogels, with water absorption 86.21%, had little impact on growth of mouse fibroblast (L929) and presented good cell biocompatibility. Obvious sudden degradation stage, slow degradation stage and no apparent toxicity was observed after AZ-HECTS hydrogels implanted into rats, and tissue inflammation was slighter, which indicated favorable biological safety. Furthermore, AZ-HECTS hydrogels was loaded with heparin, and released 50% of heparin accumulated 14d. AZ-HECTS-heparin hydrogels showed inhibitory effects on L929, and pro-growth functions within vascular endothelial cells seeded on the hydrogels, meanwhile a positive influence on vascular endothelial growth factor expression. In conclusion, AZ-HECTS hydrogels possessed favorable biocompatibility and biodegradability and had good potential as drug carrier. Copyright © 2017 Elsevier Ltd. All rights reserved.

Sonochemically synthesized biocompatible zirconium phosphate nanoparticles for pH sensitive drug delivery application.

PubMed

Kalita, Himani; Prashanth Kumar, B N; Konar, Suraj; Tantubay, Sangeeta; Kr Mahto, Madhusudan; Mandal, Mahitosh; Pathak, Amita

2016-03-01

The present work reports the synthesis of biocompatible zirconium phosphate (ZP) nanoparticles as nanocarrier for drug delivery application. The ZP nanoparticles were synthesized via a simple sonochemical method in the presence of cetyltrimethylammonium bromide and their efficacy for the delivery of drugs has been tested through various in-vitro experiments. The particle size and BET surface area of the nanoparticles were found to be ~48 nm and 206.51 m(2)/g respectively. The conventional MTT assay and cellular localization studies of the particles, performed on MDA-MB-231 cell lines, demonstrate their excellent biocompatibility and cellular internalization behavior. The loading of curcumin, an antitumor drug, onto the ZP nanoparticles shows the rapid drug uptake ability of the particles, while the drug release study, performed at two different pH values (at 7.4 and 5) depicts pH sensitive release-profile. The MTT assay and cellular localization studies revealed higher cellular inhibition and better bioavailability of the nanoformulated curcumin compared to free curcumin. Copyright © 2015 Elsevier B.V. All rights reserved.

Association of Biocompatible Peritoneal Dialysis Solutions with Peritonitis Risk, Treatment, and Outcomes

PubMed Central

Cho, Yeoungjee; Badve, Sunil V.; Hawley, Carmel M.; McDonald, Stephen P.; Brown, Fiona G.; Boudville, Neil; Bannister, Kym M.; Clayton, Philip A.

2013-01-01

Summary Background and objectives The effect of biocompatible peritoneal dialysis (PD) solutions on PD-related peritonitis is unclear. This study sought to evaluate the relationship between use of biocompatible solutions and the probability of occurrence or clinical outcomes of peritonitis. Design, setting, participants, & measurements The study included all incident Australian patients receiving PD between January 1, 2007, and December 31, 2010, using Australia and New Zealand Dialysis and Transplant Registry data. All multicompartment PD solutions of neutral pH were categorized as biocompatible solutions. The independent predictors of peritonitis and the use of biocompatible solutions were determined by multivariable, multilevel mixed-effects Poisson and logistic regression analysis, respectively. Sensitivity analyses, including propensity score matching, were performed. Results Use of biocompatible solutions gradually declined (from 7.5% in 2007 to 4.2% in 2010), with preferential use among smaller units and among younger patients without diabetes mellitus. Treatment with biocompatible solution was associated with significantly greater overall rate of peritonitis (0.67 versus 0.47 episode per patient-year; incidence rate ratio, 1.49; 95% confidence interval [CI], 1.19 to 1.89) and with shorter time to first peritonitis (hazard ratio [HR], 1.48; 95% CI, 1.17 to 1.87), a finding replicated in propensity score–matched cohorts (HR, 1.36; 95% CI, 1.09 to 1.71). Conclusions In an observational registry study, use of biocompatible PD solutions was associated with higher overall peritonitis rates and shorter time to first peritonitis. Further randomized studies adequately powered for a primary peritonitis outcome are warranted. PMID:23949232

Rotatable spin-polarized electron source for inverse-photoemission experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stolwijk, S. D., E-mail: Sebastian.Stolwijk@wwu.de; Wortelen, H.; Schmidt, A. B.

2014-01-15

We present a ROtatable Spin-polarized Electron source (ROSE) for the use in spin- and angle-resolved inverse-photoemission (SR-IPE) experiments. A key feature of the ROSE is a variable direction of the transversal electron beam polarization. As a result, the inverse-photoemission experiment becomes sensitive to two orthogonal in-plane polarization directions, and, for nonnormal electron incidence, to the out-of-plane polarization component. We characterize the ROSE and test its performance on the basis of SR-IPE experiments. Measurements on magnetized Ni films on W(110) serve as a reference to demonstrate the variable spin sensitivity. Moreover, investigations of the unoccupied spin-dependent surface electronic structure of Tl/Si(111)more » highlight the capability to analyze complex phenomena like spin rotations in momentum space. Essentially, the ROSE opens the way to further studies on complex spin-dependent effects in the field of surface magnetism and spin-orbit interaction at surfaces.« less

Complementary Response of Static Spin-Stripe Order and Superconductivity to Nonmagnetic Impurities in Cuprates

DOE PAGES

Guguchia, Z.; Roessli, B.; Khasanov, R.; ...

2017-08-22

Here, we report muon-spin rotation and neutron-scattering experiments on nonmagnetic Zn impurity effects on the static spin-stripe order and superconductivity of the La214 cuprates. Remarkably, it was found that, for samples with hole doping x≈1/8, the spin-stripe ordering temperature T so decreases linearly with Zn doping y and disappears at y≈4%, demonstrating a high sensitivity of static spin-stripe order to impurities within a CuO 2 plane. Moreover, Tso is suppressed by Zn in the same manner as the superconducting transition temperature Tc for samples near optimal hole doping. This surprisingly similar sensitivity suggests that the spin-stripe order is dependent onmore » intertwining with superconducting correlations.« less

Complementary Response of Static Spin-Stripe Order and Superconductivity to Nonmagnetic Impurities in Cuprates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guguchia, Z.; Roessli, B.; Khasanov, R.

Here, we report muon-spin rotation and neutron-scattering experiments on nonmagnetic Zn impurity effects on the static spin-stripe order and superconductivity of the La214 cuprates. Remarkably, it was found that, for samples with hole doping x≈1/8, the spin-stripe ordering temperature T so decreases linearly with Zn doping y and disappears at y≈4%, demonstrating a high sensitivity of static spin-stripe order to impurities within a CuO 2 plane. Moreover, Tso is suppressed by Zn in the same manner as the superconducting transition temperature Tc for samples near optimal hole doping. This surprisingly similar sensitivity suggests that the spin-stripe order is dependent onmore » intertwining with superconducting correlations.« less

Spin-torque diode frequency tuning via soft exchange pinning of both magnetic layers

NASA Astrophysics Data System (ADS)

Khudorozhkov, A. A.; Skirdkov, P. N.; Zvezdin, K. A.; Vetoshko, P. M.; Popkov, A. F.

2017-12-01

A spin-torque diode, which is a magnetic tunnel junction with magnetic layers softly pinned at some tilt to each other, is proposed. The resonance operating frequency of such a dual exchange-pinned spin-torque diode can be significantly higher (up to 9.5 GHz) than that of a traditional free layer spin-torque diode, and, at the same time, the sensitivity remains rather high. Using micromagnetic modeling we show that the maximum microwave sensitivity of the considered diode is reached at the bias current densities slightly below the self-sustained oscillations initiating. The dependence of the resonance frequency and the sensitivity on the angle between pinning exchange fields is presented. Thus, a way of designing spin-torque diode with a given resonance response frequency in the microwave region in the absence of an external magnetic field is proposed.

Liquid-state nuclear spin comagnetometers.

PubMed

Ledbetter, M P; Pustelny, S; Budker, D; Romalis, M V; Blanchard, J W; Pines, A

2012-06-15

We discuss nuclear spin comagnetometers based on ultralow-field nuclear magnetic resonance in mixtures of miscible solvents, each rich in a different nuclear spin. In one version thereof, Larmor precession of protons and 19F nuclei in a mixture of thermally polarized pentane and hexafluorobenzene is monitored via a sensitive alkali-vapor magnetometer. We realize transverse relaxation times in excess of 20 s and suppression of magnetic field fluctuations by a factor of 3400. We estimate it should be possible to achieve single-shot sensitivity of about 5×10(-9)  Hz, or about 5×10(-11)  Hz in ≈1 day of integration. In a second version, spin precession of protons and 129Xe nuclei in a mixture of pentane and hyperpolarized liquid xenon is monitored using superconducting quantum interference devices. Application to spin-gravity experiments, electric dipole moment experiments, and sensitive gyroscopes is discussed.

K-band single-chip electron spin resonance detector.

PubMed

Anders, Jens; Angerhofer, Alexander; Boero, Giovanni

2012-04-01

We report on the design, fabrication, and characterization of an integrated detector for electron spin resonance spectroscopy operating at 27 GHz. The microsystem, consisting of an LC-oscillator and a frequency division module, is integrated onto a single silicon chip using a conventional complementary metal-oxide-semiconductor technology. The achieved room temperature spin sensitivity is about 10(8)spins/G Hz(1/2), with a sensitive volume of about (100 μm)(3). Operation at 77K is also demonstrated. Copyright © 2012 Elsevier Inc. All rights reserved.

Dynamic strain-mediated coupling of a single diamond spin to a mechanical resonator

NASA Astrophysics Data System (ADS)

Ovartchaiyapong, Preeti; Lee, Kenneth W.; Myers, Bryan A.; Jayich, Ania C. Bleszynski

2014-07-01

The development of hybrid quantum systems is central to the advancement of emerging quantum technologies, including quantum information science and quantum-assisted sensing. The recent demonstration of high-quality single-crystal diamond resonators has led to significant interest in a hybrid system consisting of nitrogen-vacancy centre spins that interact with the resonant phonon modes of a macroscopic mechanical resonator through crystal strain. However, the nitrogen-vacancy spin-strain interaction has not been well characterized. Here, we demonstrate dynamic, strain-mediated coupling of the mechanical motion of a diamond cantilever to the spin of an embedded nitrogen-vacancy centre. Via quantum control of the spin, we quantitatively characterize the axial and transverse strain sensitivities of the nitrogen-vacancy ground-state spin. The nitrogen-vacancy centre is an atomic scale sensor and we demonstrate spin-based strain imaging with a strain sensitivity of 3 × 10-6 strain Hz-1/2. Finally, we show how this spin-resonator system could enable coherent spin-phonon interactions in the quantum regime.

Improving the Sensitivity of Mass Spectrometry by Using a New Sheath Flow Electrospray Emitter Array at Subambient Pressures

DOE PAGES

Cox, Jonathan T.; Marginean, Ioan; Kelly, Ryan T.; ...

2014-03-28

Arrays of chemically etched emitters with individualized sheath gas capillaries have been developed to enhance electrospray ionization (ESI) at subambient pressures. By including an emitter array in a subambient pressure ionization with nanoelectrospray (SPIN) source, ionization and transmission efficiency can be maximized allowing for increased sensitivity in mass spectrometric analyses. The SPIN source eliminates the major ion losses at conventional ESI-mass spectrometry (MS) interface by placing the emitter in the first vacuum region of the instrument. To facilitate stable electrospray currents in such conditions we have developed an improved emitter array with individualized sheath gas around each emitter. The utilitymore » of the new emitter arrays for generating stable multi-electrosprays at subambient pressures was probed by coupling the emitter array/SPIN source with a time of flight (TOF) mass spectrometer. The instrument sensitivity was compared between single emitter/SPIN-MS and multi-emitter/SPIN-MS configurations using an equimolar solution of 9 peptides. An increase in sensitivity correlative to the number of emitters in the array was observed.« less

Improving the Sensitivity of Mass Spectrometry by Using a New Sheath Flow Electrospray Emitter Array at Subambient Pressures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cox, Jonathan T.; Marginean, Ioan; Kelly, Ryan T.

Arrays of chemically etched emitters with individualized sheath gas capillaries have been developed to enhance electrospray ionization (ESI) at subambient pressures. By including an emitter array in a subambient pressure ionization with nanoelectrospray (SPIN) source, ionization and transmission efficiency can be maximized allowing for increased sensitivity in mass spectrometric analyses. The SPIN source eliminates the major ion losses at conventional ESI-mass spectrometry (MS) interface by placing the emitter in the first vacuum region of the instrument. To facilitate stable electrospray currents in such conditions we have developed an improved emitter array with individualized sheath gas around each emitter. The utilitymore » of the new emitter arrays for generating stable multi-electrosprays at subambient pressures was probed by coupling the emitter array/SPIN source with a time of flight (TOF) mass spectrometer. The instrument sensitivity was compared between single emitter/SPIN-MS and multi-emitter/SPIN-MS configurations using an equimolar solution of 9 peptides. An increase in sensitivity correlative to the number of emitters in the array was observed.« less

High Sensitivity Combined with Extended Structural Coverage of Labile Compounds via Nanoelectrospray Ionization at Subambient Pressures

DOE PAGES

Cox, Jonathan T.; Kronewitter, Scott R.; Shukla, Anil K.; ...

2014-09-15

Subambient pressure ionization with nanoelectrospray (SPIN) has proven to be effective in producing ions with high efficiency and transmitting them to low pressures for high sensitivity mass spectrometry (MS) analysis. Here we present evidence that not only does the SPIN source improve MS sensitivity but also allows for gentler ionization conditions. The gentleness of a conventional heated capillary electrospray ionization (ESI) source and the SPIN source was compared by the liquid chromatography mass spectrometry (LC-MS) analysis of colominic acid. Colominic acid is a mixture of sialic acid polymers of different lengths containing labile glycosidic linkages between monomer units necessitating amore » gentle ion source. By coupling the SPIN source with high resolution mass spectrometry and using advanced data processing tools, we demonstrate much extended coverage of sialic acid polymer chains as compared to using the conventional ESI source. Additionally we show that SPIN-LC-MS is effective in elucidating polymer features with high efficiency and high sensitivity previously unattainable by the conventional ESI-LC-MS methods.« less

Preparation and characterization of electrospun in-situ cross-linked gelatin-graphite oxide nanofibers.

PubMed

Zhan, Jianchao; Morsi, Yosry; Ei-Hamshary, Hany; Al-Deyab, Salem S; Mo, Xiumei

2016-01-01

Electrospun gelatin(Gel) nanofibers scaffold has such defects as poor mechanical property and quick degradation due to high solubility. In this study, the in situ cross-linked electrospinning technique was used for the production of gelatin nanofibers. Deionized water was chosen as the spinning solvent and graphite oxide (GO) was chosen as the enhancer. The morphological structure, porosity, thermal property, moisture absorption, and moisture retention performance, hydrolysis resistance, mechanical property, and biocompatibility of the produced nanofibers were investigated. Compared with in situ cross-linked gelatin nanofibers scaffold, in situ cross-linked Gel-GO nanofibers scaffold has the following features: (1) the hydrophilicity, moisture absorption, and moisture retention performance slightly reduce, while the hydrolysis resistance is improved; (2) the breaking strength, breaking elongation, and Young's modulus are significantly improved; (3) the porosity slightly reduces while the biocompatibility considerably increases. The in situ cross-linked Gel-GO nanofibers scaffold is likely to be applied in such fields as drug delivery and scaffold for skin tissue engineering.

A Comparative Biocompatibility Analysis of Ternary Nitinol Alloys

PubMed Central

Haider, Waseem; Munroe, Norman; Pulletikurthi, Chandan; Singh Gill, Puneet K.; Amruthaluri, Sushma

2009-01-01

Nitinol alloys are rapidly being utilized as the material of choice in a variety of applications in the medical industry. It has been used for self-expanding stents, graft support systems, and various other devices for minimally invasive interventional and endoscopic procedures. However, the biocompatibility of this alloy remains a concern to many practitioners in the industry due to nickel sensitivity experienced by many patients. In recent times, several new Nitinol alloys have been introduced with the addition of a ternary element. Nevertheless, there is still a dearth of information concerning the biocompatibility and corrosion resistance of these alloys. This study compared the biocompatibility of two ternary Nitinol alloys prepared by powder metallurgy (PM) and arc melting (AM) and critically assessed the influence of the ternary element. ASTM F 2129-08 cyclic polarization in vitro corrosion tests were conducted to evaluate the corrosion resistance in phosphate buffered saline (PBS). The growth of endothelial cells on NiTi was examined using optical microscopy. PMID:19956791

A Comparative Biocompatibility Analysis of Ternary Nitinol Alloys

NASA Astrophysics Data System (ADS)

Haider, Waseem; Munroe, Norman; Pulletikurthi, Chandan; Gill, Puneet K. Singh; Amruthaluri, Sushma

2009-08-01

Nitinol alloys are rapidly being utilized as the material of choice in a variety of applications in the medical industry. It has been used for self-expanding stents, graft support systems, and various other devices for minimally invasive interventional and endoscopic procedures. However, the biocompatibility of this alloy remains a concern to many practitioners in the industry due to nickel sensitivity experienced by many patients. In recent times, several new Nitinol alloys have been introduced with the addition of a ternary element. Nevertheless, there is still a dearth of information concerning the biocompatibility and corrosion resistance of these alloys. This study compared the biocompatibility of two ternary Nitinol alloys prepared by powder metallurgy (PM) and arc melting (AM) and critically assessed the influence of the ternary element. ASTM F 2129-08 cyclic polarization in vitro corrosion tests were conducted to evaluate the corrosion resistance in phosphate buffered saline (PBS). The growth of endothelial cells on NiTi was examined using optical microscopy.

A Comparative Biocompatibility Analysis of Ternary Nitinol Alloys.

PubMed

Haider, Waseem; Munroe, Norman; Pulletikurthi, Chandan; Singh Gill, Puneet K; Amruthaluri, Sushma

2009-08-01

Nitinol alloys are rapidly being utilized as the material of choice in a variety of applications in the medical industry. It has been used for self-expanding stents, graft support systems, and various other devices for minimally invasive interventional and endoscopic procedures. However, the biocompatibility of this alloy remains a concern to many practitioners in the industry due to nickel sensitivity experienced by many patients. In recent times, several new Nitinol alloys have been introduced with the addition of a ternary element. Nevertheless, there is still a dearth of information concerning the biocompatibility and corrosion resistance of these alloys. This study compared the biocompatibility of two ternary Nitinol alloys prepared by powder metallurgy (PM) and arc melting (AM) and critically assessed the influence of the ternary element. ASTM F 2129-08 cyclic polarization in vitro corrosion tests were conducted to evaluate the corrosion resistance in phosphate buffered saline (PBS). The growth of endothelial cells on NiTi was examined using optical microscopy.

Biocompatible Pressure Sensing Skins for Minimally Invasive Surgical Instruments

PubMed Central

Arabagi, Veaceslav; Felfoul, Ouajdi; Gosline, Andrew H.; Wood, Robert J.; Dupont, Pierre E.

2016-01-01

This paper presents 800-μm thick, biocompatible sensing skins composed of arrays of pressure sensors. The arrays can be configured to conform to the surface of medical instruments so as to act as disposable sensing skins. In particular, the fabrication of cylindrical geometries is considered here for use on endoscopes. The sensing technology is based on polydimethylsiloxane synthetic silicone encapsulated microchannels filled with a biocompatible salt-saturated glycerol solution, functioning as the conductive medium. A multi-layer manufacturing approach is introduced that enables stacking sensing microchannels, mechanical stress concentration features, and electrical routing via flexcircuits in a thickness of less than 1 mm. The proposed approach is inexpensive and does not require clean room tools or techniques. The mechanical stress concentration features are implemented using a patterned copper layer that serves to improve sensing range and sensitivity. Sensor performance is demonstrated experimentally using a sensing skin mounted on a neuroendoscope insertion cannula and is shown to outperform previously developed non-biocompatible sensors. PMID:27642266

High-sensitivity GMR with low coercivity in top-IrMn spin-valves

NASA Astrophysics Data System (ADS)

Liu, H. R.; Qu, B. J.; Ren, T. L.; Liu, L. T.; Xie, H. L.; Li, C. X.; Ku, W. J.

2003-12-01

Top-IrMn spin-valves with a structure of Ta/NiFe/CoFe/Cu/CoFe/IrMn/Ta have been investigated. The spin-valves were deposited by high vacuum DC magnetron sputtering at room temperature. The magnetoresistance ratio reaches 9.12% at room temperature. The coercivity of the free layer and the exchange bias field is 1.04 and 180 Oe, respectively. The maximum sensitivity of the spin-valves is 8.36%/Oe. A reduction of 33.2% of the coercivity was obtained after a 2-min RIE process. Utilizing standard integrated circuit (IC) process, mass production of robust giant magnetoresistance sensors can be achieved with these spin-valve thin films.

Imaging Magnetization Structure and Dynamics in Ultrathin Y3Fe5O12/Pt Bilayers with High Sensitivity Using the Time-Resolved Longitudinal Spin Seebeck Effect

NASA Astrophysics Data System (ADS)

Bartell, Jason M.; Jermain, Colin L.; Aradhya, Sriharsha V.; Brangham, Jack T.; Yang, Fengyuan; Ralph, Daniel C.; Fuchs, Gregory D.

2017-04-01

We demonstrate an instrument for time-resolved magnetic imaging that is highly sensitive to the in-plane magnetization state and dynamics of thin-film bilayers of yttrium iron garnet [Y3Fe5O12(YIG )]/Pt : the time-resolved longitudinal spin Seebeck (TRLSSE) effect microscope. We detect the local in-plane magnetic orientation within the YIG by focusing a picosecond laser to generate thermally driven spin current from the YIG into the Pt by the spin Seebeck effect and then use the inverse spin Hall effect in the Pt to transduce this spin current to an output voltage. To establish the time resolution of TRLSSE, we show that pulsed optical heating of patterned YIG (20 nm )/Pt (6 nm )/Ru (2 nm ) wires generates a magnetization-dependent voltage pulse of less than 100 ps. We demonstrate TRLSSE microscopy to image both static magnetic structure and gigahertz-frequency magnetic resonance dynamics with submicron spatial resolution and a sensitivity to magnetic orientation below 0.3 °/√{H z } in ultrathin YIG.

Biocompatibility of hyaluronic acid hydrogels prepared by porous hyaluronic acid microbeads

NASA Astrophysics Data System (ADS)

Kim, Jin-Tae; Lee, Deuk Yong; Kim, Tae-Hyung; Song, Yo-Seung; Cho, Nam-Ihn

2014-05-01

Hyaluronic acid hydrogels (HAHs) were synthesized by immersing HA microbeads crosslinked with divinyl sulfone in a phosphate buffered saline solution to evaluate the biocompatibility of the gels by means of cytotoxicity, genotoxicity ( in vitro chromosome aberration test, reverse mutation assay, and in vivo micronucleus test), skin sensitization, and intradermal reactivity. The HAHs induced no cytotoxicity or genotoxicity. In guinea pigs treated with grafts and prostheses, no animals died and there were no abnormal clinical signs. The sensitization scores were zero in all guinea pigs after 24 h and 48 h challenge, suggesting that the HAHs had no contact allergic sensitization in the guinea pig maximization test. No abnormal signs were found in New Zealand White rabbits during the 72 h observation period after the injection. There was no difference between the HAHs and negative control mean scores because skin reaction such as erythema or oedema was not observed after injection. Experimental results suggest that the HAHs would be suitable for soft tissue augmentation due to the absence of cytotoxicity, genotoxicity, skin sensitization, and intradermal reactivity.

Computations of the chirality-sensitive effect induced by an antisymmetric indirect spin–spin coupling

NASA Astrophysics Data System (ADS)

Garbacz, Piotr

2018-05-01

Results of quantum mechanical computations of the antisymmetric part of the indirect spin-spin coupling tensor, ?, performed using the coupled-cluster method, the second-order polarisation propagator approximation, and the density functional theory for 25 molecules and nearly 100 spin-spin couplings are reported. These results are used for an estimation of the magnitude of the recently proposed liquid-state nuclear magnetic resonance chirality-sensitive effect, which allows to determine the molecular chirality directly, i.e. without the need for the application of any chiral agent. The following were found: (i) the antisymmetry J⋆ is usually larger for the coupling between spins separated by two chemical bonds in comparison with the coupling through one bond, (ii) promising samples are those which contain fluorine, and (iii) the antisymmetry of the spin-spin coupling tensor is of the order of a few hertz for commercially available chemical compounds. Therefore, the relevant property of the experiment, the pseudoscalar Jc, for them is of the order of 1 nHz m/V.

A fluorescent nanosensor based on graphene quantum dots-aptamer probe and graphene oxide platform for detection of lead (II) ion.

PubMed

Qian, Zhao Sheng; Shan, Xiao Yue; Chai, Lu Jing; Chen, Jian Rong; Feng, Hui

2015-06-15

The sensitive detection of heavy metal ions in the organism and aquatic ecosystem using nanosensors based on environment friendly and biocompatible materials still remains a challenge. A fluorescent turn-on nanosensor for lead (II) detection based on biocompatible graphene quantum dots and graphene oxide by employment of Pb(2+)-induced G-quadruplex formation was reported. Graphene quantum dots with high quantum yield, good biocompatibility were prepared and served as the fluorophore of Pb(2+) probe. Fluorescence turn-off of graphene quantum dots is easily achieved through efficient photoinduced electron transfer between graphene quantum dots and graphene oxide, and subsequent fluorescence turn-on process is due to the formation of G-quadraplex aptamer-Pb(2+) complex triggered by the addition of Pb(2+). This nanosensor can distinguish Pb(2+) ion from other ions with high sensitivity and good reproducibility. The detection method based on this nanosensor possesses a fast response time of one minute, a broad linear span of up to 400.0 nM and ultralow detection limit of 0.6 nM. Copyright © 2015 Elsevier B.V. All rights reserved.

Imaging free radicals in organelles, cells, tissue, and in vivo with immuno-spin trapping.

PubMed

Mason, Ronald Paul

2016-08-01

The accurate and sensitive detection of biological free radicals in a reliable manner is required to define the mechanistic roles of such species in biochemistry, medicine and toxicology. Most of the techniques currently available are either not appropriate to detect free radicals in cells and tissues due to sensitivity limitations (electron spin resonance, ESR) or subject to artifacts that make the validity of the results questionable (fluorescent probe-based analysis). The development of the immuno-spin trapping technique overcomes all these difficulties. This technique is based on the reaction of amino acid- and DNA base-derived radicals with the spin trap 5, 5-dimethyl-1-pyrroline N-oxide (DMPO) to form protein- and DNA-DMPO nitroxide radical adducts, respectively. These adducts have limited stability and decay to produce the very stable macromolecule-DMPO-nitrone product. This stable product can be detected by mass spectrometry, NMR or immunochemistry by the use of anti-DMPO nitrone antibodies. The formation of macromolecule-DMPO-nitrone adducts is based on the selective reaction of free radical addition to the spin trap and is thus not subject to artifacts frequently encountered with other methods for free radical detection. The selectivity of spin trapping for free radicals in biological systems has been proven by ESR. Immuno-spin trapping is proving to be a potent, sensitive (a million times higher sensitivity than ESR), and easy (not quantum mechanical) method to detect low levels of macromolecule-derived radicals produced in vitro and in vivo. Anti-DMPO antibodies have been used to determine the distribution of free radicals in cells and tissues and even in living animals. In summary, the invention of the immuno-spin trapping technique has had a major impact on the ability to accurately and sensitively detect biological free radicals and, subsequently, on our understanding of the role of free radicals in biochemistry, medicine and toxicology. Published by Elsevier B.V.

Tailoring the mechanical properties of SU-8/clay nanocomposites: polymer microcantilever fabrication perspective

NASA Astrophysics Data System (ADS)

Chen, Hao; Ojijo, Vincent; Cele, Hastings; Joubert, Trudi; Suprakas, Sinha Ray; Land, Kevin

2014-06-01

SU-8/Clay nanocomposite is considered as a candidate material for microcantilever sensor fabrication. Organically modified montmorillonite clay nanoparticles are dispersed in the universally used negative photoresist polymer SU-8, for a low cost material, which is also biocompatible. If varying the clay loading of the composite material yields a variation of the Young's modulus, the tailored material stiffness presents an opportunity for fabrication of microcantilevers with tunable sensor sensitivity. With this microcantilever application perspective, mechanical and thermal properties of the material were investigated. SU-8/Clay nanocomposite samples were prepared with clay loadings from 1wt% - 10wt%. Tensile test results show a general trend of increase in composite modulus with an increase in the clay loading up to 7wt%, followed by a small drop at 10wt%. The composite material indeed yields moderate variation of the Young's modulus. It was also found that the thermal degradation peak of the material occurred at 300°C, which is beyond the operating temperature of typical microcantilever sensor applications. The fabrication of a custom designed microcantilever array chip with the SU-8/Clay nanocomposite material was achieved in a class 100 cleanroom, using spin-coating and photolithography microfabrication techniques. The optimization of the process for fabricating microcantilever with the SU-8/Clay nanocomposite material is discussed in this paper. The results of this research are promising for cheaper mass production of low cost disposable, yet sensitive, microcantilever sensor elements, including biosensor applications.

Nanofiber Based Optical Sensors for Oxygen Determination

NASA Astrophysics Data System (ADS)

Xue, Ruipeng

Oxygen sensors based on luminescent quenching of nanofibers were developed for measurement of both gaseous and dissolved oxygen concentrations. Electrospinning was used to fabricate "core-shell" fiber configurations in which oxygen-sensitive transition metal complexes are embedded into a polymer 'core' while a synthetic biocompatible polymer provides a protective 'shell.' Various matrix polymers and luminescent probes were studied in terms of their sensitivity, linear calibration, reversibility, response time, stability and probe-matrix interactions. Due to the small size and high surface area of these nanofibers, all samples showed rapid response and a highly linear response to oxygen. The sensitivity and photostability of the sensors were controlled by the identity of both the probe molecule and the polymer matrix. Such nanofiber sensor forms are particularly suitable in biological applications due to the fact that they do not consume oxygen, are biocompatible and biomimetic and can be easily incorporated into cell culture. Applications of these fibers in cancer cell research, wound healing, breath analysis and waste water treatment were explored.

Development of nanostars as a biocompatible tumor contrast agent: toward in vivo SERS imaging.

PubMed

D'Hollander, Antoine; Mathieu, Evelien; Jans, Hilde; Vande Velde, Greetje; Stakenborg, Tim; Van Dorpe, Pol; Himmelreich, Uwe; Lagae, Liesbet

2016-01-01

The need for sensitive imaging techniques to detect tumor cells is an important issue in cancer diagnosis and therapy. Surface-enhanced Raman scattering (SERS), realized by chemisorption of compounds suitable for Raman spectroscopy onto gold nanoparticles, is a new method for detecting a tumor. As a proof of concept, we studied the use of biocompatible gold nanostars as sensitive SERS contrast agents targeting an ovarian cancer cell line (SKOV3). Due to a high intracellular uptake of gold nanostars after 6 hours of exposure, they could be detected and located with SERS. Using these nanostars for passive targeting after systemic injection in a xenograft mouse model, a detectable signal was measured in the tumor and liver in vivo. These signals were confirmed by ex vivo SERS measurements and darkfield microscopy. In this study, we established SERS nanostars as a highly sensitive contrast agent for tumor detection, which opens the potential for their use as a theranostic agent against cancer.

Integration of Biomaterials into Sensors Based on Organic Thin-Film Transistors.

PubMed

Wu, Xiaohan; Zhou, Jiachen; Huang, Jia

2018-05-22

Sensors based on organic thin-film transistors (OTFTs) present various advantages, including high sensitivity and mechanical flexibility, thus possessing potential applications such as wearable devices and biomedical electronics for health monitoring, etc. However, such applications are partially limited by the biocompatibility, biodegradability, and sensitivity to target analytes of OTFT-based sensors, which can be improved by the incorporation of diverse biomaterials. This article presents a brief review from the viewpoint of the type of the integrated biomaterials, including naturally occurring biomacromolecules such as proteins, enzymes, and deoxyribonucleic acid, as well as biocompatible polymers such as polylactide, poly(lactide-co-glycolide), poly(ethylene glycol), cellulose, polydimethylsiloxane, parylene, etc. It is believed that future work in this field should be devoted to the selectivity, sensitivity, and stability improvement as well as the high-level integration and sophistication on the basis of the OTFT-based sensors for physical, chemical, and biological sensing applications. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Origanum vulgare mediated green synthesis of biocompatible gold nanoparticles simultaneously possessing plasmonic, antioxidant and antimicrobial properties

PubMed Central

Cuibus, Flavia; Sevastre, Bogdan; Stiufiuc, Gabriela; Duma, Mihaela; Hanganu, Daniela; Iacovita, Cristian; Stiufiuc, Rares; Lucaciu, Constantin Mihai

2018-01-01

Purpose The leaves and flowering stem of Origanum vulgare contain essential oils, flavonoids, phenolic acids and anthocyanins. We propose a new, simple, one-pot, O. vulgare extract (OVE) mediated green synthesis method of biocompatible gold nanoparticles (AuNPs) possessing improved antioxidant, antimicrobial and plasmonic properties. Materials and methods Different concentrations of OVEs were used to reduce gold ions and to synthetize biocompatible spherical AuNPs. Their morphology and physical properties have been investigated by means of transmission electron microscopy, ultraviolet–visible absorption spectroscopy, photon correlation spectroscopy and Fourier transform infrared spectroscopy, whereas their plasmonic properties have been tested using surface-enhanced Raman spectroscopy (SERS). The antioxidant properties of nanoparticles (NPs) have been evaluated by 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay, and the antimicrobial tests were performed using the disk diffusion assay. Their cytotoxicity has been assessed by means of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Results The experimental results confirmed the successful synthesis of biocompatible, spherical, plasmonic NPs having a mean diameter of ~40 nm and an outstanding aqueous stability. This new class of NPs exhibits a very good antioxidant activity and presents interesting inhibitory effects against Staphylococcus aureus and Candida albicans. Due to their plasmonic properties, AuNPs are used as SERS substrates for the detection of a test molecule (methylene blue) up to a concentration of 10−7 M and a pharmaceutical compound (propranolol) in solution. Cytotoxicity assays revealed that AuNPs are better tolerated by normal human dermal fibroblast cells, while the melanoma cancer cells are more sensitive. Conclusion The biocompatible AuNPs synthetized using OVEs showed significant bactericidal and antimycotic activities, the most sensitive microorganisms being S. aureus and C. albicans, both commonly involved in various dermatological infections. Moreover, the significant antioxidant effect might recommend their use for protective and/or preventive effect in various skin inflammatory conditions, including the reduction in side effects in dermatological infections. Meanwhile, the as-synthesized biocompatible AuNPs can be successfully used as SERS substrates for the detection of pharmaceutical compounds in aqueous solutions. PMID:29503540

Searching for gravitational waves from compact binaries with precessing spins

NASA Astrophysics Data System (ADS)

Harry, Ian; Privitera, Stephen; Bohé, Alejandro; Buonanno, Alessandra

2016-07-01

Current searches for gravitational waves from compact-object binaries with the LIGO and Virgo observatories employ waveform models with spins aligned (or antialigned) with the orbital angular momentum. Here, we derive a new statistic to search for compact objects carrying generic (precessing) spins. Applying this statistic, we construct banks of both aligned- and generic-spin templates for binary black holes and neutron star-black hole binaries, and compare the effectualness of these banks towards simulated populations of generic-spin systems. We then use these banks in a pipeline analysis of Gaussian noise to measure the increase in background incurred by using generic- instead of aligned-spin banks. Although the generic-spin banks have roughly a factor of ten more templates than the aligned-spin banks, we find an overall improvement in signal recovery at a fixed false-alarm rate for systems with high-mass ratio and highly precessing spins. This gain in sensitivity comes at a small loss of sensitivity (≲4 %) for systems that are already well covered by aligned-spin templates. Since the observation of even a single binary merger with misaligned spins could provide unique astrophysical insights into the formation of these sources, we recommend that the method described here be developed further to mount a viable search for generic-spin binary mergers in LIGO/Virgo data.

Reaching the quantum limit of sensitivity in electron spin resonance

DOE PAGES

Bienfait, A.; Pla, J. J.; Kubo, Y.; ...

2015-12-14

The detection and characterization of paramagnetic species by electron spin resonance (ESR) spectroscopy is widely used throughout chemistry, biology and materials science, from in vivo imaging to distance measurements in spin-labelled proteins. ESR relies on the inductive detection of microwave signals emitted by the spins into a coupled microwave resonator during their Larmor precession. However, such signals can be very small, prohibiting the application of ESR at the nanoscale (for example, at the single-cell level or on individual nanoparticles). Here in this work, using a Josephson parametric microwave amplifier combined with high-quality-factor superconducting microresonators cooled at millikelvin temperatures, we improvemore » the state-of-the-art sensitivity of inductive ESR detection by nearly four orders of magnitude. We demonstrate the detection of 1,700 bismuth donor spins in silicon within a single Hahn echo with unit signal-to-noise ratio, reduced to 150 spins by averaging a single Carr-Purcell-Meiboom-Gill sequence. This unprecedented sensitivity reaches the limit set by quantum fluctuations of the electromagnetic field instead of thermal or technical noise, which constitutes a novel regime for magnetic resonance. In conclusion, the detection volume of our resonator is ~0.02nl, and our approach can be readily scaled down further to improve sensitivity, providing a new versatile toolbox for ESR at the nanoscale.« less

Magnetic Spin Effects in Photoprocesses inside Polymeric Photoconductors

NASA Astrophysics Data System (ADS)

Rumyantsev, B. M.; Berendyaev, V. I.; Pebalk, A. V.

2018-06-01

Magnetic spin effects are detected and studied in the processes of sensitized current-carrier photogeneration and luminescence inside polymer photoconductor films based on polyimides and composites of polymers with carbazole moieties combined with electron acceptors (chemical sensitization) and dyes (spectral sensitization). The effect an electric field has on the quantum yield of photogeneration and the luminescence of excited charge-transfer complexes (reversible and irreversible effects) at spectral sensitization is studied in the presence of O2.

Storing quantum information in spins and high-sensitivity ESR

NASA Astrophysics Data System (ADS)

Morton, John J. L.; Bertet, Patrice

2018-02-01

Quantum information, encoded within the states of quantum systems, represents a novel and rich form of information which has inspired new types of computers and communications systems. Many diverse electron spin systems have been studied with a view to storing quantum information, including molecular radicals, point defects and impurities in inorganic systems, and quantum dots in semiconductor devices. In these systems, spin coherence times can exceed seconds, single spins can be addressed through electrical and optical methods, and new spin systems with advantageous properties continue to be identified. Spin ensembles strongly coupled to microwave resonators can, in principle, be used to store the coherent states of single microwave photons, enabling so-called microwave quantum memories. We discuss key requirements in realising such memories, including considerations for superconducting resonators whose frequency can be tuned onto resonance with the spins. Finally, progress towards microwave quantum memories and other developments in the field of superconducting quantum devices are being used to push the limits of sensitivity of inductively-detected electron spin resonance. The state-of-the-art currently stands at around 65 spins per √{ Hz } , with prospects to scale down to even fewer spins.

Storing quantum information in spins and high-sensitivity ESR.

PubMed

Morton, John J L; Bertet, Patrice

2018-02-01

Quantum information, encoded within the states of quantum systems, represents a novel and rich form of information which has inspired new types of computers and communications systems. Many diverse electron spin systems have been studied with a view to storing quantum information, including molecular radicals, point defects and impurities in inorganic systems, and quantum dots in semiconductor devices. In these systems, spin coherence times can exceed seconds, single spins can be addressed through electrical and optical methods, and new spin systems with advantageous properties continue to be identified. Spin ensembles strongly coupled to microwave resonators can, in principle, be used to store the coherent states of single microwave photons, enabling so-called microwave quantum memories. We discuss key requirements in realising such memories, including considerations for superconducting resonators whose frequency can be tuned onto resonance with the spins. Finally, progress towards microwave quantum memories and other developments in the field of superconducting quantum devices are being used to push the limits of sensitivity of inductively-detected electron spin resonance. The state-of-the-art currently stands at around 65 spins per Hz, with prospects to scale down to even fewer spins. Copyright © 2017. Published by Elsevier Inc.

Multiphoton luminescent graphene quantum dots for in vivo tracking of human adipose-derived stem cells

NASA Astrophysics Data System (ADS)

Kim, Jin; Song, Sung Ho; Jin, Yoonhee; Park, Hyun-Ji; Yoon, Hyewon; Jeon, Seokwoo; Cho, Seung-Woo

2016-04-01

The applicability of graphene quantum dots (GQDs) for the in vitro and in vivo live imaging and tracking of different types of human stem cells is investigated. GQDs synthesized by the modified graphite intercalated compound method show efficient cellular uptake with improved biocompatibility and highly sensitive optical properties, indicating their feasibility as a bio-imaging probe for stem cell therapy.The applicability of graphene quantum dots (GQDs) for the in vitro and in vivo live imaging and tracking of different types of human stem cells is investigated. GQDs synthesized by the modified graphite intercalated compound method show efficient cellular uptake with improved biocompatibility and highly sensitive optical properties, indicating their feasibility as a bio-imaging probe for stem cell therapy. Electronic supplementary information (ESI) available: Additional results. See DOI: 10.1039/c6nr02143c

Cell Culture on MEMS Platforms: A Review

PubMed Central

Ni, Ming; Tong, Wen Hao; Choudhury, Deepak; Rahim, Nur Aida Abdul; Iliescu, Ciprian; Yu, Hanry

2009-01-01

Microfabricated systems provide an excellent platform for the culture of cells, and are an extremely useful tool for the investigation of cellular responses to various stimuli. Advantages offered over traditional methods include cost-effectiveness, controllability, low volume, high resolution, and sensitivity. Both biocompatible and bio-incompatible materials have been developed for use in these applications. Biocompatible materials such as PMMA or PLGA can be used directly for cell culture. However, for bio-incompatible materials such as silicon or PDMS, additional steps need to be taken to render these materials more suitable for cell adhesion and maintenance. This review describes multiple surface modification strategies to improve the biocompatibility of MEMS materials. Basic concepts of cell-biomaterial interactions, such as protein adsorption and cell adhesion are covered. Finally, the applications of these MEMS materials in Tissue Engineering are presented. PMID:20054478

Magnetostrictive GMR spin valves with composite FeGa/FeCo free layers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Luping; Institute of Materials Science, School of Materials Science and Engineering, Shanghai University, Shanghai 200072; Zhan, Qingfeng, E-mail: zhanqf@nimte.ac.cn, E-mail: runweili@nimte.ac.cn

2016-03-15

We have fabricated strain-sensitive spin valves on flexible substrates by utilizing the large magnetostrictive FeGa alloy to promote the strain sensitivity and the composite free layer of FeGa/FeCo to avoid the drastic reduction of giant magnetoresistance (GMR) ratio. This kind of spin valve (SV-FeGa/FeCo) displays a MR ratio about 5.9%, which is comparable to that of the conventional spin valve (SV-FeCo) with a single FeCo free layer. Different from the previously reported works on magnetostrictive spin valves, the SV-FeGa/FeCo displays an asymmetric strain dependent GMR behavior. Upon increasing the lateral strain, the MR ratio for the ascending branch decreases moremore » quickly than that for the descending branch, which is ascribed to the formation of a spiraling spin structure around the FeGa/FeCo interface under the combined influences of both magnetic field and mechanical strain. A strain sensitivity of GF = 7.2 was achieved at a magnetic bias field of -30 Oe in flexible SV-FeGa/FeCo, which is significantly larger than that of SV-FeCo.« less

Spin-dependent μ → e conversion

DOE PAGES

Cirigliano, Vincenzo; Davidson, Sacha; Kuno, Yoshitaka

2017-05-22

The experimental sensitivity to μ→e conversion on nuclei is expected to improve by four orders of magnitude in coming years. Here, we consider the impact of μ→e flavour-changing tensor and axial-vector four-fermion operators which couple to the spin of nucleons. Such operators, which have not previously been considered, contribute to μ→e conversion in three ways: in nuclei with spin they mediate a spin-dependent transition; in all nuclei they contribute to the coherent (A 2-enhanced) spin-independent conversion via finite recoil effects and via loop mixing with dipole, scalar, and vector operators. Furthermore, we estimate the spin-dependent rate in Aluminium (the targetmore » of the upcoming COMET and Mu2e experiments), show that the loop effects give the greatest sensitivity to tensor and axial-vector operators involving first-generation quarks, and discuss the complementarity of the spin-dependent and independent contributions to μ→e conversion.« less

Spin-dependent μ → e conversion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cirigliano, Vincenzo; Davidson, Sacha; Kuno, Yoshitaka

The experimental sensitivity to μ→e conversion on nuclei is expected to improve by four orders of magnitude in coming years. Here, we consider the impact of μ→e flavour-changing tensor and axial-vector four-fermion operators which couple to the spin of nucleons. Such operators, which have not previously been considered, contribute to μ→e conversion in three ways: in nuclei with spin they mediate a spin-dependent transition; in all nuclei they contribute to the coherent (A 2-enhanced) spin-independent conversion via finite recoil effects and via loop mixing with dipole, scalar, and vector operators. Furthermore, we estimate the spin-dependent rate in Aluminium (the targetmore » of the upcoming COMET and Mu2e experiments), show that the loop effects give the greatest sensitivity to tensor and axial-vector operators involving first-generation quarks, and discuss the complementarity of the spin-dependent and independent contributions to μ→e conversion.« less

Room-temperature in situ nuclear spin hyperpolarization from optically pumped nitrogen vacancy centres in diamond

DOE PAGES

King, Jonathan P.; Jeong, Keunhong; Vassiliou, Christophoros C.; ...

2015-12-07

Low detection sensitivity stemming from the weak polarization of nuclear spins is a primary limitation of magnetic resonance spectroscopy and imaging. Methods have been developed to enhance nuclear spin polarization but they typically require high magnetic fields, cryogenic temperatures or sample transfer between magnets. Here we report bulk, room-temperature hyperpolarization of 13C nuclear spins observed via high-field magnetic resonance. The technique harnesses the high optically induced spin polarization of diamond nitrogen vacancy centres at room temperature in combination with dynamic nuclear polarization. We observe bulk nuclear spin polarization of 6%, an enhancement of ~170,000 over thermal equilibrium. The signal ofmore » the hyperpolarized spins was detected in situ with a standard nuclear magnetic resonance probe without the need for sample shuttling or precise crystal orientation. In conclusion, hyperpolarization via optical pumping/dynamic nuclear polarization should function at arbitrary magnetic fields enabling orders of magnitude sensitivity enhancement for nuclear magnetic resonance of solids and liquids under ambient conditions.« less

Strain-mediated mechanical coupling to diamond spins

NASA Astrophysics Data System (ADS)

Bleszynski Jayich, Ania

2015-03-01

Nitrogen-vacancy (NV) centers in diamond are atomic-scale spin systems with remarkable quantum properties that persist to room temperature. The recent demonstration of high-quality single-crystal diamond resonators has led to significant interest in a hybrid system consisting of NV spins that interact with the resonant phonon modes of a macroscopic mechanical resonator through crystal strain. We demonstrate dynamic, strain-mediated coupling of the mechanical motion of a diamond cantilever to the spin of an embedded NV. Via quantum control of the spin, we quantitatively characterize the axial and transverse strain sensitivities of the nitrogen-vacancy ground-state spin. The nitrogen-vacancy center is an atomic scale sensor and we demonstrate spin-based strain imaging with a strain sensitivity of 3x10-6 strain Hz1/2. We discuss prospects for reaching the regime of quantum coupling between phonons and spins, and we present our results in this direction. This hybrid system has exciting prospects for a phonon-based approach to integrating NVs into quantum networks. Funding from the AFOSR MURI and NSF CAREER programs are gratefully acknowledged.

Spin-sensitive interference due to Majorana state on the interface between normal and superconducting leads

NASA Astrophysics Data System (ADS)

Barański, J.; Kobiałka, A.; Domański, T.

2017-02-01

We investigate the subgap spectrum and transport properties of the quantum dot on the interface between the metallic and superconducting leads and additionally side-coupled to the edge of the topological superconducting (TS) chain, hosting the Majorana quasiparticle. Due to the chiral nature of the Majorana states only one spin component of the quantum dot electrons (say \\uparrow ) is directly affected, however the proximity induced on-dot pairing transmits its influence on the opposite spin as well. We investigate the unique interferometric patterns driven by the Majorana quasiparticle that are different for each spin component. We also address the spin-sensitive interplay with the Kondo effect manifested at the same zero-energy and we come to the conclusion that quantum interferometry can unambiguously identify the Majorana quasiparticle.

Electrical detection of proton-spin motion in a polymer device at room temperature

NASA Astrophysics Data System (ADS)

Boehme, Christoph

With the emergence of spintronics concepts based on organic semiconductors there has been renewed interest in the role of both, electron as well as nuclear spin states for the magneto-optoelectronic properties of these materials. In spite of decades of research on these molecular systems, there is still much need for an understanding of some of the fundamental properties of spin-controlled charge carrier transport and recombination processes. This presentation focuses on mechanisms that allow proton spin states to influence electronic transition rates in organic semiconductors. Remarkably, even at low-magnetic field conditions and room temperature, nuclear spin states with energy splittings orders of magnitude below thermal energies are able to influence observables like magnetoresistance and fluorescence. While proton spins couple to charge carrier spins via hyperfine interaction, there has been considerable debate about the nature of the electronic processes that are highly susceptible to these weak hyperfine fields. Here, experiments are presented which show how the magnetic resonant manipulation of electron and nuclear spin states in a π-conjugated polymer device causes changes of the device current. The experiments confirm the extraordinary sensitivity of electronic transitions to very weak magnetic field changes and underscore the potential significance of spin-selection rules for highly sensitive absolute magnetic fields sensor concepts. However, the relevance of these magnetic-field sensitive spin-dependent electron transitions is not just limited to semiconductor materials but also radical pair chemistry and even avian magnetoreceptors This work was supported by the US Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Award #DE-SC0000909. The Utah NSF - MRSEC program #DMR 1121252 is acknowledged for instrumentation support.

Multi-layered poly-dimethylsiloxane as a non-hermetic packaging material for medical MEMS.

PubMed

Lachhman, S; Zorman, C A; Ko, W H

2012-01-01

Poly-dimethylsiloxane (PDMS) is an attractive material for packaging implantable biomedical microdevices owing to its biocompatibility, ease in application, and bio-friendly mechanical properties. Unfortunately, devices encapsulated solely by PDMS lack the longevity for use in chronic implant applications due to defect-related moisture penetration through the packaging layer caused by conventional deposition processes such as spin coating. This paper describes an effort to improve the performance of PDMS as a packaging material by constructing the encapsulant from multiple, thin roller casted layers of PDMS as a part of a polymeric multi-material package.

Wet spinning of fibers made of chitosan and chitin nanofibrils.

PubMed

Yudin, Vladimir E; Dobrovolskaya, Irina P; Neelov, Igor M; Dresvyanina, Elena N; Popryadukhin, Pavel V; Ivan'kova, Elena M; Elokhovskii, Vladimir Yu; Kasatkin, Igor A; Okrugin, Boris M; Morganti, Pierfrancesco

2014-08-08

Biocompatible and bioresorbable composite fibers consisting of chitosan filled with anisotropic chitin nanofibrils with the length of 600-800 nm and cross section of about 11-12 nm as revealed by SEM and XRD were prepared by coagulation. Both chitin and chitosan components of the composite fibers displayed preferred orientations. Orientation of chitosan molecules induced by chitin nanocrystallites was confirmed by molecular modeling. The incorporation of 0.1-0.3 wt.% of chitin nanofibrils into chitosan matrix led to an increase in strength and Young modulus of the composite fibers. Copyright © 2014 Elsevier Ltd. All rights reserved.

Interferometrically stable, enclosed, spinning sample cell for spectroscopic experiments on air-sensitive samples

NASA Astrophysics Data System (ADS)

Baranov, Dmitry; Hill, Robert J.; Ryu, Jisu; Park, Samuel D.; Huerta-Viga, Adriana; Carollo, Alexa R.; Jonas, David M.

2017-01-01

In experiments with high photon flux, it is necessary to rapidly remove the sample from the beam and to delay re-excitation until the sample has returned to equilibrium. Rapid and complete sample exchange has been a challenge for air-sensitive samples and for vibration-sensitive experiments. Here, a compact spinning sample cell for air and moisture sensitive liquid and thin film samples is described. The principal parts of the cell are a copper gasket sealed enclosure, a 2.5 in. hard disk drive motor, and a reusable, chemically inert glass sandwich cell. The enclosure provides an oxygen and water free environment at the 1 ppm level, as demonstrated by multi-day tests with sodium benzophenone ketyl radical. Inside the enclosure, the glass sandwich cell spins at ≈70 Hz to generate tangential speeds of 7-12 m/s that enable complete sample exchange at 100 kHz repetition rates. The spinning cell is acoustically silent and compatible with a ±1 nm rms displacement stability interferometer. In order to enable the use of the spinning cell, we discuss centrifugation and how to prevent it, introduce the cycle-averaged resampling rate to characterize repetitive excitation, and develop a figure of merit for a long-lived photoproduct buildup.

Interferometrically stable, enclosed, spinning sample cell for spectroscopic experiments on air-sensitive samples.

PubMed

Baranov, Dmitry; Hill, Robert J; Ryu, Jisu; Park, Samuel D; Huerta-Viga, Adriana; Carollo, Alexa R; Jonas, David M

2017-01-01

In experiments with high photon flux, it is necessary to rapidly remove the sample from the beam and to delay re-excitation until the sample has returned to equilibrium. Rapid and complete sample exchange has been a challenge for air-sensitive samples and for vibration-sensitive experiments. Here, a compact spinning sample cell for air and moisture sensitive liquid and thin film samples is described. The principal parts of the cell are a copper gasket sealed enclosure, a 2.5 in. hard disk drive motor, and a reusable, chemically inert glass sandwich cell. The enclosure provides an oxygen and water free environment at the 1 ppm level, as demonstrated by multi-day tests with sodium benzophenone ketyl radical. Inside the enclosure, the glass sandwich cell spins at ≈70 Hz to generate tangential speeds of 7-12 m/s that enable complete sample exchange at 100 kHz repetition rates. The spinning cell is acoustically silent and compatible with a ±1 nm rms displacement stability interferometer. In order to enable the use of the spinning cell, we discuss centrifugation and how to prevent it, introduce the cycle-averaged resampling rate to characterize repetitive excitation, and develop a figure of merit for a long-lived photoproduct buildup.

The spatial effect of protein deuteration on nitroxide spin-label relaxation: Implications for EPR distance measurement

PubMed Central

El Mkami, Hassane; Ward, Richard; Bowman, Andrew; Owen-Hughes, Tom; Norman, David G.

2014-01-01

Pulsed electron–electron double resonance (PELDOR) coupled with site-directed spin labeling is a powerful technique for the elucidation of protein or nucleic acid, macromolecular structure and interactions. The intrinsic high sensitivity of electron paramagnetic resonance enables measurement on small quantities of bio-macromolecules, however short relaxation times impose a limit on the sensitivity and size of distances that can be measured using this technique. The persistence of the electron spin-echo, in the PELDOR experiment, is one of the most crucial limitations to distance measurement. At a temperature of around 50 K one of the predominant factors affecting persistence of an echo, and as such, the sensitivity and measurable distance between spin labels, is the electron spin echo dephasing time (Tm). It has become normal practice to use deuterated solvents to extend Tm and recently it has been demonstrated that deuteration of the underlying protein significantly extends Tm. Here we examine the spatial effect of segmental deuteration of the underlying protein, and also explore the concentration and temperature dependence of highly deuterated systems. PMID:25310878

Sensitive Spin Detection Using An On-Chip Squid-Waveguide Resonator

NASA Astrophysics Data System (ADS)

Yue, Guang

Quantum computing gives novel way of computing using quantum mechanics, which furthers human knowledge and has exciting applications. Quantum systems with diluted spins such as rare earth ions hosted in single crystal, molecule-based magnets etc. are promising qubits candidates to form the basis of a quantum computer. High sensitivity measurement and coherent control of these spin systems are crucial for their practical usage as qubits. The micro-SQUID (direct-current micrometer-sized Superconducting QUantum Interference Device) is capable to measure magnetization of spin system with high sensitivity. For example, the micro-SQUID technique can measure magnetic moments as small as several thousand muB as shown by the study of [W. Wernsdorfer, Supercond. Sci. Technol. 22, 064013 (2009)]. Here we develop a novel on-chip setup that combines the micro-SQUID sensitivity with microwave excitation. Such setup can be used for electron spin resonance measurements or coherent control of spins utilizing the high sensitivity of micro-SQUID for signal detection. To build the setup, we studied the fabrication process of the micro-SQUID, which is made of weak-linked Josephson junctions. The SQUID as a detector is integrated on the same chip with a shorted coplanar waveguide, so that the microwave pulses can be applied through the waveguide to excite the sample for resonance measurements. The whole device is plasma etched from a thin (˜ 20nm) niobium film, so that the SQUID can work at in large in-plane magnetic fields of several tesla. In addition, computer simulations are done to find the best design of the waveguide such that the microwave excitation field is sufficiently strong and uniformly applied to the sample. The magnetization curve of Mn12 molecule-based magnet sample is measured to prove the proper working of the micro-SQUID. Electron spin resonance measurement is done on the setup for gadolinium ions diluted in a CaWO4 single crystal. The measurement shows clear evidence of the resonance signal from the 1st transition of the gadolinium ions' energy levels, which shows the setup is successfully built. Due to the high sensitivity of micro-SQUID and the ability to concentrate microwave energy in small areas of the chip, this setup can detect signals from a small number of spins (107) in a small volume (several mum 3).

Fabrication and characterization of electrospun cellulose/nano-hydroxyapatite nanofibers for bone tissue engineering.

PubMed

Ao, Chenghong; Niu, Yan; Zhang, Ximu; He, Xu; Zhang, Wei; Lu, Canhui

2017-04-01

Nanofibrous scaffolds from cotton cellulose and nano-hydroxyapatite (nano-HA) were electrospun for bone tissue engineering. The solution properties of cellulose/nano-HA spinning dopes and their associated electrospinnability were characterized. Morphological, thermal and mechanical properties of the electrospun cellulose/nano-HA nanocomposite nanofibers (ECHNN) were measured and the biocompatibility of ECHNN with human dental follicle cells (HDFCs) was evaluated. Scanning electron microscope (SEM) images indicated that the average diameter of ECHNN increased with a higher nano-HA loading and the fiber diameter distributions were well within the range of natural ECM (extra cellular matrix) fibers (50-500nm). The ECHNN exhibited extraordinary mechanical properties with a tensile strength and a Young's modulus up to 70.6MPa and 3.12GPa respectively. Moreover, it was discovered that the thermostability of the ECHNN could be enhanced with the incorporation of nano-HA. Cell culture experiments demonstrated that the ECHNN scaffolds were quite biocompatible for HDFCs attachment and proliferation, suggesting their great potentials as scaffold materials in bone tissue engineering. Copyright © 2017 Elsevier B.V. All rights reserved.

Optical implementation of spin squeezing

NASA Astrophysics Data System (ADS)

Ono, Takafumi; Sabines-Chesterking, Javier; Cable, Hugo; O'Brien, Jeremy L.; Matthews, Jonathan C. F.

2017-05-01

Quantum metrology enables estimation of optical phase shifts with precision beyond the shot-noise limit. One way to exceed this limit is to use squeezed states, where the quantum noise of one observable is reduced at the expense of increased quantum noise for its complementary partner. Because shot-noise limits the phase sensitivity of all classical states, reduced noise in the average value for the observable being measured allows for improved phase sensitivity. However, additional phase sensitivity can be achieved using phase estimation strategies that account for the full distribution of measurement outcomes. Here we experimentally investigate a model of optical spin-squeezing, which uses post-selection and photon subtraction from the state generated using a parametric downconversion photon source, and we investigate the phase sensitivity of this model. The Fisher information for all photon-number outcomes shows it is possible to obtain a quantum advantage of 1.58 compared to the shot-noise value for five-photon events, even though due to experimental imperfection, the average noise for the relevant spin-observable does not achieve sub-shot-noise precision. Our demonstration implies improved performance of spin squeezing for applications to quantum metrology.

Bottom Extreme-Ultraviolet-Sensitive Coating for Evaluation of the Absorption Coefficient of Ultrathin Film

NASA Astrophysics Data System (ADS)

Hijikata, Hayato; Kozawa, Takahiro; Tagawa, Seiichi; Takei, Satoshi

2009-06-01

A bottom extreme-ultraviolet-sensitive coating (BESC) for evaluation of the absorption coefficients of ultrathin films such as extreme ultraviolet (EUV) resists was developed. This coating consists of a polymer, crosslinker, acid generator, and acid-responsive chromic dye and is formed by a conventional spin-coating method. By heating the film after spin-coating, a crosslinking reaction is induced and the coating becomes insoluble. A typical resist solution can be spin-coated on a substrate covered with the coating film. The evaluation of the linear absorption coefficients of polymer films was demonstrated by measuring the EUV absorption of BESC substrates on which various polymers were spin-coated.

Surface cytologic features on intraocular lenses: can increased biocompatibility have disadvantages?

PubMed

Hollick, E J; Spalton, D J; Ursell, P G

1999-07-01

To compare the anterior surface cytologic features and effect on blood-aqueous barrier of polymethyl methacrylate, silicone, and hydrogel intraocular lens (IOL) implants to give an indication of their biocompatibility. This prospective study was performed at an English-teaching hospital. Ninety eyes were randomized to receive a polymethyl methacrylate, silicone, or hydrogel implant. A standardized surgical protocol was performed by a single surgeon using phacoemulsification. Patients were seen at intervals for 1 year. Measurements of visual acuity, contrast sensitivity, and anterior chamber laser flare and cells were obtained; and an assessment of lens cytologic features using specular microscopy of the anterior IOL surface was performed. Visual acuity and contrast sensitivity were not significantly different among the 3 groups. Hydrogel IOLs were associated with fewer inflammatory cells on their surface than polymethyl methacrylate and silicone IOLs (P<.001), but with significantly more lens epithelial cells (LECs) (P<.001). Patients with hydrogel implants without LECs had greater blood-aqueous barrier breakdown than those with LECs. The hydrogel IOLs were associated with a reduced inflammatory cell reaction but had many more LECs on their anterior surface. Those IOLs associated with increased blood-aqueous barrier damage did not develop LECs. If an IOL is too biocompatible, then it may incite the growth of LECs over its surface, which could have disadvantages.

Controlled delivery of basal insulin from phase-sensitive polymeric systems after subcutaneous administration: in vitro release, stability, biocompatibility, in vivo absorption, and bioactivity of insulin.

PubMed

Al-Tahami, Khaled; Oak, Mayura; Singh, Jagdish

2011-06-01

The purpose of this study was to investigate the phase-sensitive delivery systems (D,L-polylactide in triacetin) for controlled delivery of insulin at basal level. The effect of varying concentration of zinc, polymer, and insulin on the in vitro release of insulin was evaluated. Stability of released insulin was investigated by differential scanning calorimetry, circular dichroism, and matrix-assisted laser desorption/ionization time of flight mass spectrometry. In Vivo insulin absorption and bioactivity were studied in diabetic rats. In vitro and In Vivo biocompatibility of delivery systems were evaluated by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay and skin histology, respectively. Extended release profiles of insulin for 2, 4, and 8 weeks from delivery systems containing 20%, 30%, and 40% (w/v) polymer concentration was observed. A ratio of 1:5 insulin hexamer to zinc was shown to be optimum. Physical and chemical stability of released insulin was greatly conserved. In Vivo studies demonstrated controlled release of insulin with reduction in blood glucose for approximately 1 month. In vitro and In Vivo studies demonstrated that the delivery system was biocompatible and controlled the delivery of insulin for longer durations after single subcutaneous injection. Copyright © 2010 Wiley-Liss, Inc.

Nano Superconducting Quantum Interference device: A powerful tool for nanoscale investigations

NASA Astrophysics Data System (ADS)

Granata, Carmine; Vettoliere, Antonio

2016-02-01

The magnetic sensing at nanoscale level is a promising and interesting research topic of nanoscience. Indeed, magnetic imaging is a powerful tool for probing biological, chemical and physical systems. The study of small spin cluster, like magnetic molecules and nanoparticles, single electron, cold atom clouds, is one of the most stimulating challenges of applied and basic research of the next years. In particular, the magnetic nanoparticle investigation plays a fundamental role for the modern material science and its relative technological applications like ferrofluids, magnetic refrigeration and biomedical applications, including drug delivery, hyper-thermia cancer treatment and magnetic resonance imaging contrast-agent. Actually, one of the most ambitious goals of the high sensitivity magnetometry is the detection of elementary magnetic moment or spin. In this framework, several efforts have been devoted to the development of a high sensitivity magnetic nanosensor pushing sensing capability to the individual spin level. Among the different magnetic sensors, Superconducting QUantum Interference Devices (SQUIDs) exhibit an ultra high sensitivity and are widely employed in numerous applications. Basically, a SQUID consists of a superconducting ring (sensitive area) interrupted by two Josephson junctions. In the recent years, it has been proved that the magnetic response of nano-objects can be effectively measured by using a SQUID with a very small sensitive area (nanoSQUID). In fact, the sensor noise, expressed in terms of the elementary magnetic moment (spin or Bohr magneton), is linearly dependent on the SQUID loop side length. For this reason, SQUIDs have been progressively miniaturized in order to improve the sensitivity up to few spin per unit of bandwidth. With respect to other techniques, nanoSQUIDs offer the advantage of direct measurement of magnetization changes in small spin systems. In this review, we focus on nanoSQUIDs and its applications. In particular, we will discuss the motivations, the theoretical aspects, the fabrication techniques, the different nanoSQUIDs and the relative nanoscale applications.

Hyperfine-induced spin relaxation of a diffusively moving carrier in low dimensions: Implications for spin transport in organic semiconductors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mkhitaryan, V. V.; Dobrovitski, V. V.

2015-08-24

The hyperfine coupling between the spin of a charge carrier and the nuclear spin bath is a predominant channel for the carrier spin relaxation in many organic semiconductors. We theoretically investigate the hyperfine-induced spin relaxation of a carrier performing a random walk on a d-dimensional regular lattice, in a transport regime typical for organic semiconductors. We show that in d=1 and 2, the time dependence of the space-integrated spin polarization P(t) is dominated by a superexponential decay, crossing over to a stretched-exponential tail at long times. The faster decay is attributed to multiple self-intersections (returns) of the random-walk trajectories, whichmore » occur more often in lower dimensions. We also show, analytically and numerically, that the returns lead to sensitivity of P(t) to external electric and magnetic fields, and this sensitivity strongly depends on dimensionality of the system (d=1 versus d=3). We investigate in detail the coordinate dependence of the time-integrated spin polarization σ(r), which can be probed in the spin-transport experiments with spin-polarized electrodes. We also demonstrate that, while σ(r) is essentially exponential, the effect of multiple self-intersections can be identified in transport measurements from the strong dependence of the spin-decay length on the external magnetic and electric fields.« less

One-step Synthesis of Highly Luminescent Nitrogen-doped Carbon Dots for Selective and Sensitive Detection of Mercury(II) Ions and Cellular Imaging.

PubMed

Liu, Ying; Liao, Mei; He, Xueling; Liu, Xia; Kou, Xingming; Xiao, Dan

2015-01-01

In this paper, nitrogen-doped carbon dots (N-CDs) with high quantum yield (QY) of 40.5% were prepared through a facile and straightforward hydrothermal route. The as-prepared N-CDs exhibited excellent photoluminescence properties, good water-solublity and photostability, negligible cytotoxicity and favourable biocompatibility. Such N-CDs were found to serve as an effective fluorescent sensor for selective and sensitive detection of Hg(2+) in a wide linear response concentration range of 0 - 8 μM with a limit of detection (LOD) of 0.087 μM and could be applied to the determination of Hg(2+) in environmental water samples. The corresponding mechanisms were discussed in detail. Moreover, another attractive finding was that the N-CDs showed satisfactory performance in bioimaging before and after the addition of Hg(2+) in human lung cancer PC14 cells. With excellent sensitivity, selectivity and biocompatibility, such cheap carbonmaterials are potentially suitable for monitoring of Hg(2+) in environmental applications and promising for biological applications.

Scanned-probe detection of electron spin resonance from a nitroxide spin probe

PubMed Central

Moore, Eric W.; Lee, SangGap; Hickman, Steven A.; Wright, Sarah J.; Harrell, Lee E.; Borbat, Peter P.; Freed, Jack H.; Marohn, John A.

2009-01-01

We report an approach that extends the applicability of ultrasensitive force-gradient detection of magnetic resonance to samples with spin-lattice relaxation times (T 1) as short as a single cantilever period. To demonstrate the generality of the approach, which relies on detecting either cantilever frequency or phase, we used it to detect electron spin resonance from a T 1 = 1 ms nitroxide spin probe in a thin film at 4.2 K and 0.6 T. By using a custom-fabricated cantilever with a 4 μm-diameter nickel tip, we achieve a magnetic resonance sensitivity of 400 Bohr magnetons in a 1 Hz bandwidth. A theory is presented that quantitatively predicts both the lineshape and the magnitude of the observed cantilever frequency shift as a function of field and cantilever-sample separation. Good agreement was found between nitroxide T 1 's measured mechanically and inductively, indicating that the cantilever magnet is not an appreciable source of spin-lattice relaxation here. We suggest that the new approach has a number of advantages that make it well suited to push magnetic resonance detection and imaging of nitroxide spin labels in an individual macromolecule to single-spin sensitivity. PMID:20018707

Thermotropic phase behavior of choline soaps.

PubMed

Klein, Regina; Dutton, Helen; Diat, Olivier; Tiddy, Gordon J T; Kunz, Werner

2011-04-14

Choline carboxylates (ChCm with m = 12-18) are simple biocompatible anionic surfactants with very low Krafft temperatures, possessing a rich aqueous phase behavior. In the present work, we have investigated the thermotropic mesomorphism of anhydrous ChCm salts for m = 12-18. Transition temperatures and enthalpies determined by differential scanning calorimetry reveal that all investigated compounds exhibit three different phases between -20 and 95 °C. The phases were further characterized by optical polarizing microscopy, NMR spin-spin relaxation, and X-ray scattering measurements. The nature of the phases was identified with increasing temperature as crystalline, semicrystalline, and liquid-crystalline lamellar. Even long-chain choline carboxylates (m = 18) were found to melt into a lamellar liquid-crystalline phase below 100 °C. Accordingly, with choline as counterion in simple fatty acid soaps, not only the water solubility is considerably enhanced but also the melting points are substantially reduced, hence facilitating thermotropic mesomorphism at temperatures between 35 and 95 °C. Thus, simple choline soaps with m = 12-18 may be classified as ionic liquids.

Hybrid microfabrication of nanofiber-based sheets and rods for tissue engineering applications.

PubMed

Park, Suk-Hee; Kim, Min Sung; Lee, Dasom; Choi, Yong Whan; Kim, Deok-Ho; Suh, Kahp-Yang

2013-12-01

Electrospun nanofibers have been developed into a variety of forms for tissue engineering scaffolds to regulate the cellular functions guided by nanotopographical cues. Here, we have successfully fabricated nanofiber-based scaffold complexes of rod and sheet type by combining the three microfabrication techniques of electrospinning, spin coating, and polymer melt deposition. It was demonstrated that this hybrid fabrication could produce uniaxially aligned nanofiber scaffolds supported by a thin film, allowing for a mechanically enforced substrate for cell culture as well as facile scaffold manipulation. The results of cell analysis indicated that nanofibers on spin-coated films could provide contact guidance effects on cells and retain them even after manipulation. As an application of the cell-laden nanofiber film, we built a rod-type structure by rolling up the film around a mechanically supporting core microfiber, which was incorporated by polymer melt deposition. A biocompatible and biodegradable polymer, polycaprolactone, was used throughout the processes and thus could be used as a directly implantable substitute in tissue regeneration.

Spin pumping and inverse spin Hall effects—Insights for future spin-orbitronics (invited)

DOE PAGES

Zhang, Wei; Jungfleisch, Matthias B.; Jiang, Wanjun; ...

2015-03-13

Quantification of spin-charge interconversion has become increasingly important in the fast-developing field of spin-orbitronics. Pure spin current generated by spin pumping acts a sensitive probe for many bulk and interface spin-orbit effects, which has been indispensable for the discovery of many promising new spin-orbit materials. Here, we apply spin pumping and inverse spin Hall effect experiments, as a useful metrology, and study spin-orbit effects in a variety of metals and metal interfaces. We also quantify the spin Hall effects in Ir and W using the conventional bilayer structures, and discuss the self-induced voltage in a single layer of ferromagnetic permalloy.more » Finally, we extend our discussions to multilayer structures and quantitatively reveal the spin current flow in two consecutive normal metal layers.« less

High-sensitivity operation of single-beam optically pumped magnetometer in a kHz frequency range

DOE PAGES

Savukov, Igor Mykhaylovich; Kim, Y. J.; Shah, V.; ...

2017-02-02

Here, optically pumped magnetometers (OPM) can be used in various applications, from magnetoencephalography to magnetic resonance imaging and nuclear quadrupole resonance (NQR). OPMs provide high sensitivity and have the significant advantage of non-cryogenic operation. To date, many magnetometers have been demonstrated with sensitivity close to 1 fT, but most devices are not commercialized. Most recently, QuSpin developed a model of OPM that is low cost, high sensitivity, and convenient for users, which operates in a single-beam configuration. Here we developed a theory of single-beam (or parallel two-beam) magnetometers and showed that it is possible to achieve good sensitivity beyond theirmore » usual frequency range by tuning the magnetic field. Experimentally we have tested and optimized a QuSpin OPM for operation in the frequency range from DC to 1.7 kHz, and found that the performance was only slightly inferior despite the expected decrease due to deviation from the spin-exchange relaxation-free regime.« less

High-sensitivity operation of single-beam optically pumped magnetometer in a kHz frequency range

DOE Office of Scientific and Technical Information (OSTI.GOV)

Savukov, Igor Mykhaylovich; Kim, Y. J.; Shah, V.

Here, optically pumped magnetometers (OPM) can be used in various applications, from magnetoencephalography to magnetic resonance imaging and nuclear quadrupole resonance (NQR). OPMs provide high sensitivity and have the significant advantage of non-cryogenic operation. To date, many magnetometers have been demonstrated with sensitivity close to 1 fT, but most devices are not commercialized. Most recently, QuSpin developed a model of OPM that is low cost, high sensitivity, and convenient for users, which operates in a single-beam configuration. Here we developed a theory of single-beam (or parallel two-beam) magnetometers and showed that it is possible to achieve good sensitivity beyond theirmore » usual frequency range by tuning the magnetic field. Experimentally we have tested and optimized a QuSpin OPM for operation in the frequency range from DC to 1.7 kHz, and found that the performance was only slightly inferior despite the expected decrease due to deviation from the spin-exchange relaxation-free regime.« less

Magnetoresistive sensitivity and uniaxial anisotropy of spin-valve microstrips with a synthetic antiferromagnet

NASA Astrophysics Data System (ADS)

Chernyshova, T. A.; Milyaev, M. A.; Naumova, L. I.; Proglyado, V. V.; Bannikova, N. S.; Maksimova, I. K.; Petrov, I. A.; Ustinov, V. V.

2017-05-01

Microobjects (strips) were formed by contact photolithography using Ta/Ni80Fe20/Co90Fe10/Cu/Co90Fe10/Ru/Co90Fe10/Fe50Mn50/Ta spin-valves prepared by magnetron sputtering. A mutually perpendicular arrangement of uniaxial and unidirectional anisotropy axes in microobjects has been formed using two different thermomagnetic treatment regimes. The magnetoresistive sensitivity of spin valve and spin-valve-based microobject has been found to depend on the mutual arrangement of the easy magnetization axis and direction of magnetic field applied upon thermomagnetic treatment. The obtained data have been interpreted taking into account changes in the induced anisotropy and anisotropy due to the shape of the microobject.

Quantum gyroscope based on Berry phase of spins in diamond

NASA Astrophysics Data System (ADS)

Song, Xuerui; Wang, Liujun; Diao, Wenting; Duan, Chongdi

2018-02-01

Gyroscope is the crucial sensor of the inertial navigation system, there is always high demand to improve the sensitivity and reduce the size of the gyroscopes. Using the NV center electronic spin and nuclear spin qubits in diamond, we introduce the research of new types of quantum gyroscopes based on the Berry phase shifts of the spin states during the rotation of the sensor systems. Compared with the performance of the traditional MEMS gyroscope, the sensitivity of the new types of quantum gyroscopes was highly improved and the spatial resolution was reduced to nano-scale. With the help of micro-manufacturing technology in the semiconductor industry, the quantum gyroscopes introduced here can be further integrated into chip-scale sensors.

Sensitizing solid state nuclear magnetic resonance of dilute nuclei by spin-diffusion assisted polarization transfers.

PubMed

Lupulescu, Adonis; Frydman, Lucio

2011-10-07

Recent years have witnessed efforts geared at increasing the sensitivity of NMR experiments, by relying on the suitable tailoring and exploitation of relaxation phenomena. These efforts have included the use of paramagnetic agents, enhanced (1)H-(1)H incoherent and coherent transfers processes in 2D liquid state spectroscopy, and homonuclear (13)C-(13)C spin diffusion effects in labeled solids. The present study examines some of the opportunities that could open when exploiting spontaneous (1)H-(1)H spin-diffusion processes, to enhance relaxation and to improve the sensitivity of dilute nuclei in solid state NMR measurements. It is shown that polarization transfer experiments executed under sufficiently fast magic-angle-spinning conditions, enable a selective polarization of the dilute low-γ spins by their immediate neighboring protons. Repolarization of the latter can then occur during the time involved in monitoring the signal emitted by the low-γ nuclei. The basic features involved in the resulting approach, and its potential to improve the effective sensitivity of solid state NMR measurements on dilute nuclei, are analyzed. Experimental tests witness the advantages that could reside from utilizing this kind of approach over conventional cross-polarization processes. These measurements also highlight a number of limitations that will have to be overcome for transforming selective polarization transfers of this kind into analytical methods of choice. © 2011 American Institute of Physics

Dark matter sensitivity of multi-ton liquid xenon detectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schumann, Marc; Bütikofer, Lukas; Baudis, Laura

2015-10-01

We study the sensitivity of multi ton-scale time projection chambers using a liquid xenon target, e.g., the proposed DARWIN instrument, to spin-independent and spin-dependent WIMP-nucleon scattering interactions. Taking into account realistic backgrounds from the detector itself as well as from neutrinos, we examine the impact of exposure, energy threshold, background rejection efficiency and energy resolution on the dark matter sensitivity. With an exposure of 200 t × y and assuming detector parameters which have been already demonstrated experimentally, spin-independent cross sections as low as 2.5 × 10{sup −49} cm{sup 2} can be probed for WIMP masses around 40 GeV/c{sup 2}. Additional improvementsmore » in terms of background rejection and exposure will further increase the sensitivity, while the ultimate WIMP science reach will be limited by neutrinos scattering coherently off the xenon nuclei.« less

Controlling measurement-induced nonlocality in the Heisenberg XX model by three-spin interactions

NASA Astrophysics Data System (ADS)

Xie, Yu-Xia; Sun, Yu-Hang; Li, Zhao

2018-01-01

We investigate the well-defined measures of measurement-induced nonlocality (MIN) for thermal states of the transverse field XX model, with the addition of three-spin interaction terms being introduced. The results showed that the MINs are very sensitive to system parameters of the chain. The three-spin interactions can serve as flexible parameters for enhancing MINs of the boundary spins, and the maximum enhancement achievable by varying strengths of the three-spin interactions are different for the chain with different number of spins.

Spin-flop states in a synthetic antiferromagnet and variations of unidirectional anisotropy in FeMn-based spin valves

NASA Astrophysics Data System (ADS)

Milyaev, M. A.; Naumova, L. I.; Chernyshova, T. A.; Proglyado, V. V.; Kulesh, N. A.; Patrakov, E. I.; Kamenskii, I. Yu.; Ustinov, V. V.

2016-12-01

Spin valves with a synthetic antiferromagnet have been prepared by magnetron sputtering. Regularities of the formation of single- and two-phase spin-flop states in the synthetic antiferromagnet have been studied using magnetoresistance measurements and imaging the magnetic structure. A thermomagnetic treatment of spin valve in a field that corresponds to the single-phase spin-flop state of synthetic antiferromagnet was shown to allow us to obtain a magnetically sensitive material characterized by hysteresis-free field dependence of the magnetoresistance.

Quantum metrology with a single spin-3/2 defect in silicon carbide

NASA Astrophysics Data System (ADS)

Soykal, Oney O.; Reinecke, Thomas L.

We show that implementations for quantum sensing with exceptional sensitivity and spatial resolution can be made using the novel features of semiconductor high half-spin multiplet defects with easy-to-implement optical detection protocols. To achieve this, we use the spin- 3 / 2 silicon monovacancy deep center in hexagonal silicon carbide based on our rigorous derivation of this defect's ground state and of its electronic and optical properties. For a single VSi- defect, we obtain magnetic field sensitivities capable of detecting individual nuclear magnetic moments. We also show that its zero-field splitting has an exceptional strain and temperature sensitivity within the technologically desirable near-infrared window of biological systems. Other point defects, i.e. 3d transition metal or rare-earth impurities in semiconductors, may also provide similar opportunities in quantum sensing due to their similar high spin (S >= 3 / 2) configurations. This work was supported in part by ONR and by the Office of Secretary of Defense, Quantum Science and Engineering Program.

NMR at pressures up to 90 GPa

NASA Astrophysics Data System (ADS)

Meier, Thomas; Khandarkhaeva, Saiana; Petitgirard, Sylvain; Körber, Thomas; Lauerer, Alexander; Rössler, Ernst; Dubrovinsky, Leonid

2018-07-01

The past 15 years have seen an astonishing increase in Nuclear Magnetic Resonance (NMR) sensitivity and accessible pressure range in high-pressure NMR experiments, owing to a series of new developments of NMR spectroscopy applied to the diamond anvil cell (DAC). Recently, with the application of electro-magnetic lenses, so-called Lenz lenses, in toroidal diamond indenter cells, pressures of up to 72 GPa with NMR spin sensitivities of about 1012 spin/Hz1/2 has been achieved. Here, we describe the implementation of a refined NMR resonator structure using a pair of double stage Lenz lenses driven by a Helmholtz coil within a standard DAC, allowing to measure sample volumes as small as 100 pl prior to compression. With this set-up, pressures close to 100 GPa could be realised repeatedly, with enhanced spin sensitivities of about 5 × 1011 spin/Hz1/2. The manufacturing and handling of these new NMR-DACs is relatively easy and straightforward, which will allow for further applications in physics, chemistry, or biochemistry.

Control of electron spin decoherence in nuclear spin baths

NASA Astrophysics Data System (ADS)

Liu, Ren-Bao

2011-03-01

Nuclear spin baths are a main mechanism of decoherence of spin qubits in solid-state systems, such as quantum dots and nitrogen-vacancy (NV) centers of diamond. The decoherence results from entanglement between the electron and nuclear spins, established by quantum evolution of the bath conditioned on the electron spin state. When the electron spin is flipped, the conditional bath evolution is manipulated. Such manipulation of bath through control of the electron spin not only leads to preservation of the center spin coherence but also demonstrates quantum nature of the bath. In an NV center system, the electron spin effectively interacts with hundreds of 13 C nuclear spins. Under repeated flip control (dynamical decoupling), the electron spin coherence can be preserved for a long time (> 1 ms) . Thereforesomecharacteristicoscillations , duetocouplingtoabonded 13 C nuclear spin pair (a dimer), are imprinted on the electron spin coherence profile, which are very sensitive to the position and orientation of the dimer. With such finger-print oscillations, a dimer can be uniquely identified. Thus, we propose magnetometry with single-nucleus sensitivity and atomic resolution, using NV center spin coherence to identify single molecules. Through the center spin coherence, we could also explore the many-body physics in an interacting spin bath. The information of elementary excitations and many-body correlations can be extracted from the center spin coherence under many-pulse dynamical decoupling control. Another application of the preserved spin coherence is identifying quantumness of a spin bath through the back-action of the electron spin to the bath. We show that the multiple transition of an NV center in a nuclear spin bath can have longer coherence time than the single transition does, when the classical noises due to inhomogeneous broadening is removed by spin echo. This counter-intuitive result unambiguously demonstrates the quantumness of the nuclear spin bath. This work was supported by Hong Kong RGC/GRF CUHK402207, CUHK402209, and CUHK402410. The author acknowledges collaboration with Nan Zhao, Jian-Liang Hu, Sai Wah Ho, Jones T. K. Wan, and Jiangfeng Du.

Electrical detection of nuclear spin-echo signals in an electron spin injection system

NASA Astrophysics Data System (ADS)

Lin, Zhichao; Rasly, Mahmoud; Uemura, Tetsuya

2017-06-01

We demonstrated spin echoes of nuclear spins in a spin injection device with a highly polarized spin source by nuclear magnetic resonance (NMR). Efficient spin injection into GaAs from a half-metallic spin source of Co2MnSi enabled efficient dynamic nuclear polarization (DNP) and sensitive detection of NMR signals even at a low magnetic field of ˜0.1 T and a relatively high temperature of 4.2 K. The intrinsic coherence time T2 of 69Ga nuclear spins was evaluated from the spin-echo signals. The relation between T2 and the decay time of the Rabi oscillation suggests that the inhomogeneous effects in our system are not obvious. This study provides an all-electrical NMR system for nuclear-spin-based qubits.

Resonant polarization transfer from electron spins to nuclear spins-or to muon spins-in semiconductors

NASA Astrophysics Data System (ADS)

Henstra, A.; Wenckebach, W. Th.

1991-02-01

A review is given of newly developed pulsed Electron Spin Resonance (ESR) methods for dynamic polarization of nuclear spins. The application of two of these methods, Nuclear Orientation Via Electron spin Locking (NOVEL) and the Integrated Solid Effect (ISE), for the polarization of nuclear spins in semiconductors is discussed in more detail. It is proposed to use these methods to study the ESR spectrum of unpaired electrons in the vicinity of muons that are bound in a solid. Thus, ESR would be observed with a sensitivity which is enhanced by about ten orders of magnitude compared to conventional ESR.

Nuclear magnetic resonance detection and spectroscopy of single proteins using quantum logic

NASA Astrophysics Data System (ADS)

Lovchinsky, I.; Sushkov, A. O.; Urbach, E.; de Leon, N. P.; Choi, S.; De Greve, K.; Evans, R.; Gertner, R.; Bersin, E.; Müller, C.; McGuinness, L.; Jelezko, F.; Walsworth, R. L.; Park, H.; Lukin, M. D.

2016-02-01

Nuclear magnetic resonance spectroscopy is a powerful tool for the structural analysis of organic compounds and biomolecules but typically requires macroscopic sample quantities. We use a sensor, which consists of two quantum bits corresponding to an electronic spin and an ancillary nuclear spin, to demonstrate room temperature magnetic resonance detection and spectroscopy of multiple nuclear species within individual ubiquitin proteins attached to the diamond surface. Using quantum logic to improve readout fidelity and a surface-treatment technique to extend the spin coherence time of shallow nitrogen-vacancy centers, we demonstrate magnetic field sensitivity sufficient to detect individual proton spins within 1 second of integration. This gain in sensitivity enables high-confidence detection of individual proteins and allows us to observe spectral features that reveal information about their chemical composition.

Electrospinning of Biodegradable and Biocompatible Nanofiber Patches from Solutions of ``Green'' Materials for Plant Protection against Fungi Attack

NASA Astrophysics Data System (ADS)

Sett, Soumyadip; Lee, Minwook; Yarin, Alexander; Moghadam, S. M. Alavi; Meinke, Matthias; Schroeder, Wolfgang

2015-11-01

Biodegradable and biocompatible soy protein/petroleum-derived polymer monolithic fibers containing adhesives were electrospun on commercial rayon pads. The polymers used, PVA and PCL, are widely used in the biomedical industry, including such applications as drug delivery and scaffold manufacturing. Soy protein is an abundant waste of SoyDiesel production, and is widely used as a nutrient. The soy content in our fibers was as high as 40% w/w. Four different adhesives, including ordinary wood glue, repositionable glue and FDA-approved pressure-sensitive glue were used for electrospinning and electrospraying. The normal and shear adhesive strengths of the patches developed in this work were measured and compared. The adhesive strength was sufficient enough to withstand normal atmospheric conditions. These biodegradable and biocompatible nano-textured patches are ready to be used on prune locations without being carried away by wind and will protect plants against fungi attack at these locations, preventing diseases like Vine Decline.

Novel levan and pNIPA temperature sensitive hydrogels for 5-ASA controlled release.

PubMed

Osman, Asila; Oner, Ebru Toksoy; Eroglu, Mehmet S

2017-06-01

Levan based cross-linker was successfully synthesized and used to prepare a series of more biocompatible and temperature responsive levan/N-isopropyl acrylamide (levan/pNIPA) hydrogels by redox polymerization at room temperature. Volume phase transition temperature (VPTT) of the hydrogels were precisely determined by derivative differential scanning calorimetry (DDSC). Incorporation of levan into the pNIPA hydrogel increased the VPTT from 32.8°C to 35.09°C, approaching to body temperature. Swelling behavior and 5-aminosalicylic acid (5-ASA) release of the hydrogels were found to vary significantly with temperature and composition. Moreover, a remarkable increase in thermal stability of levan within hydrogel with increase of pNIPA content was recorded. The biocompatibility of the hydrogels were tested against mouse fibroblast L929 cell line in phosphate buffer saline (PBS, pH 7.4). The hydrogels showed increasing biocompatibility with increasing levan ratio, indicating levan enhanced the hydrogel surface during swelling. Copyright © 2017 Elsevier Ltd. All rights reserved.

A combined EPR and MD simulation study of a nitroxyl spin label with restricted internal mobility sensitive to protein dynamics.

PubMed

Oganesyan, Vasily S; Chami, Fatima; White, Gaye F; Thomson, Andrew J

2017-01-01

EPR studies combined with fully atomistic Molecular Dynamics (MD) simulations and an MD-EPR simulation method provide evidence for intrinsic low rotameric mobility of a nitroxyl spin label, Rn, compared to the more widely employed label MTSL (R1). Both experimental and modelling results using two structurally different sites of attachment to Myoglobin show that the EPR spectra of Rn are more sensitive to the local protein environment than that of MTSL. This study reveals the potential of using the Rn spin label as a reporter of protein motions. Copyright © 2016 Elsevier Inc. All rights reserved.

Generating spin squeezing states and Greenberger-Horne-Zeilinger entanglement using a hybrid phonon-spin ensemble in diamond

NASA Astrophysics Data System (ADS)

Xia, Keyu; Twamley, Jason

2016-11-01

Quantum squeezing and entanglement of spins can be used to improve the sensitivity in quantum metrology. Here we propose a scheme to create collective coupling of an ensemble of spins to a mechanical vibrational mode actuated by an external magnetic field. We find an evolution time where the mechanical motion decouples from the spins, and the accumulated geometric phase yields a squeezing of 5.9 dB for 20 spins. We also show the creation of a Greenberger-Horne-Zeilinger spin state for 20 spins with a fidelity of ˜0.62 at cryogenic temperature. The numerical simulations show that the geometric-phase-based scheme is mostly immune to thermal mechanical noise.

Spin-labeled small unilamellar vesicles with the T1-sensitive saturation-recovery EPR display as an oxygen sensitive analyte for measurement of cellular respiration

PubMed Central

Mainali, Laxman; Vasquez-Vivar, Jeannette; Hyde, James S.; Subczynski, Witold K.

2015-01-01

This study validated the use of small unilamellar vesicles (SUVs) made of 1-palmitoyl-2-oleoylphosphatidylcholine with 1 mol% spin label of 1-palmitoyl-2-(16-doxylstearoyl)phosphatidylcholine (16-PC) as an oxygen sensitive analyte to study cellular respiration. In the analyte the hydrocarbon environment surrounds the nitroxide moiety of 16-PC. This ensures high oxygen concentration and oxygen diffusion at the location of the nitroxide as well as isolation of the nitroxide moiety from cellular reductants and paramagnetic ions that might interfere with spin-label oximetry measurements. The saturation-recovery EPR approach was applied in the analysis since this approach is the most direct method to carry out oximetric studies. It was shown that this display (spin-lattice relaxation rate) is linear in oxygen partial pressure up to 100% air (159 mmHg). Experiments using a neuronal cell line in suspension were carried out at X-band for closed chamber geometry. Oxygen consumption rates showed a linear dependence on the number of cells. Other significant benefits of the analyte are: the fast effective rotational diffusion and slow translational diffusion of the spin-probe is favorable for the measurements, and there is no cross reactivity between oxygen and paramagnetic ions in the lipid bilayer. PMID:26441482

Spin-labeled small unilamellar vesicles with the T1-sensitive saturation-recovery EPR display as an oxygen sensitive analyte for measurement of cellular respiration.

PubMed

Mainali, Laxman; Vasquez-Vivar, Jeannette; Hyde, James S; Subczynski, Witold K

2015-08-01

This study validated the use of small unilamellar vesicles (SUVs) made of 1-palmitoyl-2-oleoylphosphatidylcholine with 1 mol% spin label of 1-palmitoyl-2-(16-doxylstearoyl)phosphatidylcholine (16-PC) as an oxygen sensitive analyte to study cellular respiration. In the analyte the hydrocarbon environment surrounds the nitroxide moiety of 16-PC. This ensures high oxygen concentration and oxygen diffusion at the location of the nitroxide as well as isolation of the nitroxide moiety from cellular reductants and paramagnetic ions that might interfere with spin-label oximetry measurements. The saturation-recovery EPR approach was applied in the analysis since this approach is the most direct method to carry out oximetric studies. It was shown that this display (spin-lattice relaxation rate) is linear in oxygen partial pressure up to 100% air (159 mmHg). Experiments using a neuronal cell line in suspension were carried out at X-band for closed chamber geometry. Oxygen consumption rates showed a linear dependence on the number of cells. Other significant benefits of the analyte are: the fast effective rotational diffusion and slow translational diffusion of the spin-probe is favorable for the measurements, and there is no cross reactivity between oxygen and paramagnetic ions in the lipid bilayer.

Slotted rotatable target assembly and systematic error analysis for a search for long range spin dependent interactions from exotic vector boson exchange using neutron spin rotation

NASA Astrophysics Data System (ADS)

Haddock, C.; Crawford, B.; Fox, W.; Francis, I.; Holley, A.; Magers, S.; Sarsour, M.; Snow, W. M.; Vanderwerp, J.

2018-03-01

We discuss the design and construction of a novel target array of nonmagnetic test masses used in a neutron polarimetry measurement made in search for new possible exotic spin dependent neutron-atominteractions of Nature at sub-mm length scales. This target was designed to accept and efficiently transmit a transversely polarized slow neutron beam through a series of long open parallel slots bounded by flat rectangular plates. These openings possessed equal atom density gradients normal to the slots from the flat test masses with dimensions optimized to achieve maximum sensitivity to an exotic spin-dependent interaction from vector boson exchanges with ranges in the mm - μm regime. The parallel slots were oriented differently in four quadrants that can be rotated about the neutron beam axis in discrete 90°increments using a Geneva drive. The spin rotation signals from the 4 quadrants were measured using a segmented neutron ion chamber to suppress possible systematic errors from stray magnetic fields in the target region. We discuss the per-neutron sensitivity of the target to the exotic interaction, the design constraints, the potential sources of systematic errors which could be present in this design, and our estimate of the achievable sensitivity using this method.

Localizable entanglement in antiferromagnetic spin chains

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jin, B.-Q.; Korepin, V.E.

2004-06-01

Antiferromagnetic spin chains play an important role in condensed matter and statistical mechanics. Recently XXX spin chain was discussed in relation to information theory. Here we consider localizable entanglement. It is how much entanglement can be localized on two spins by performing local measurements on other individual spins (in a system of many interacting spins). We consider the ground state of antiferromagnetic spin chain. We study localizable entanglement [represented by concurrence] between two spins. It is a function of the distance. We start with isotropic spin chain. Then we study effects of anisotropy and magnetic field. We conclude that anisotropymore » increases the localizable entanglement. We discovered high sensitivity to a magnetic field in cases of high symmetry. We also evaluated concurrence of these two spins before the measurement to illustrate that the measurement raises the concurrence.« less

Perforated cenosphere-supported pH-sensitive spin probes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fomenko, E.V.; Bobko, A.A.; Salanov, A.N.

2008-03-15

Porous supports with an accessible internal volume and a shell providing the diffusive migration of pH-sensitive spin probes were obtained for the first time from hollow aluminosilicate cenospheres isolated from the coal fly ash. Using the methods of scanning electron microscopy and electron spin resonance, the morphology of different porous cenosphere modifications and its influence on the diffusion of spin probes from the internal volume were studied. When supporting aqueous solutions of a radical, the characteristic diffusion time for the mesoporous structure of the support is longer by a factor of 3-5 than that for the macroporous structure. Ferrospinel inmore » a content of 6 wt.% do not virtually affect the diffusion rate of spin probes. A constant rate of radical migration of similar to 1 {mu} mol min{sup -1}, determined by radical solubility in water, is achieved when a radical in the solid aggregate state is supported on the magnetic cenospheres.« less

Design and validation of a new ratiometric intracellular pH imaging probe using lanthanide-doped upconverting nanoparticles.

PubMed

Du, Shuoren; Hernández-Gil, Javier; Dong, Hao; Zheng, Xiaoyu; Lyu, Guangming; Bañobre-López, Manuel; Gallo, Juan; Sun, Ling-Dong; Yan, Chun-Hua; Long, Nicholas J

2017-10-17

pH homeostasis is strictly controlled at a subcellular level. A deregulation of the intra/extra/subcellular pH environment is associated with a number of diseases and as such, the monitoring of the pH state of cells and tissues is a valuable diagnostic tool. To date, only a few tools have been developed to measure the pH in living cells with the spatial resolution needed for intracellular imaging. Among the techniques available, only optical imaging offers enough resolution and biocompatibility to be proposed for subcellular pH monitoring. We present herein a ratiometric probe based on upconversion nanoparticles modified with a pH sensitive moiety for the quantitative imaging of pH at the subcellular level in living cells. This system provides the properties required for live cell quantitative imaging i.e. positive cellular uptake, biocompatibility, long wavelength excitation, sensitive response to pH within a biologically relevant range, and self-referenced signal.

NMR at pressures up to 90 GPa.

PubMed

Meier, Thomas; Khandarkhaeva, Saiana; Petitgirard, Sylvain; Körber, Thomas; Lauerer, Alexander; Rössler, Ernst; Dubrovinsky, Leonid

2018-05-14

The past 15 years have seen an astonishing increase in Nuclear Magnetic Resonance (NMR) sensitivity and accessible pressure range in high-pressure NMR experiments, owing to a series of new developments of NMR spectroscopy applied to the diamond anvil cell (DAC). Recently, with the application of electro-magnetic lenses, so-called Lenz lenses, in toroidal diamond indenter cells, pressures of up to 72 GPa with NMR spin sensitivities of about 10 12  spin/Hz 1/2 has been achieved. Here, we describe the implementation of a refined NMR resonator structure using a pair of double stage Lenz lenses driven by a Helmholtz coil within a standard DAC, allowing to measure sample volumes as small as 100 pl prior to compression. With this set-up, pressures close to 100 GPa could be realised repeatedly, with enhanced spin sensitivities of about 5 × 10 11 spin/Hz 1/2 . The manufacturing and handling of these new NMR-DACs is relatively easy and straightforward, which will allow for further applications in physics, chemistry, or biochemistry. Copyright © 2018 Elsevier Inc. All rights reserved.

Ultrasensitive mechanical detection of magnetic moment using a commercial disk drive write head

PubMed Central

Tao, Y.; Eichler, A.; Holzherr, T.; Degen, C. L.

2016-01-01

Sensitive detection of weak magnetic moments is an essential capability in many areas of nanoscale science and technology, including nanomagnetism, quantum readout of spins and nanoscale magnetic resonance imaging. Here we show that the write head of a commercial hard drive may enable significant advances in nanoscale spin detection. By approaching a sharp diamond tip to within 5 nm from a write pole and measuring the induced diamagnetic moment with a nanomechanical force transducer, we demonstrate a spin sensitivity of 0.032 μB Hz−1/2, equivalent to 21 proton magnetic moments. The high sensitivity is enabled in part by the pole's strong magnetic gradient of up to 28 × 106 T m−1 and in part by the absence of non-contact friction due to the extremely flat writer surface. In addition, we demonstrate quantitative imaging of the pole field with ∼10 nm spatial resolution. We foresee diverse applications for write heads in experimental condensed matter physics, especially in spintronics, ultrafast spin manipulation and mesoscopic physics. PMID:27647039

Tunable spin splitting and spin lifetime in polar WSTe monolayer

NASA Astrophysics Data System (ADS)

Adhib Ulil Absor, Moh.; Kotaka, Hiroki; Ishii, Fumiyuki; Saito, Mineo

2018-04-01

The established spin splitting with out-of-plane Zeeman spin polarizations in the monolayer (ML) of transition metal dichalcogenides (TMDs) is dictated by inversion symmetry breaking together with mirror symmetry in the surface plane. Here, by density functional theory calculations, we find that mirror symmetry breaking in the polar WSTe ML leads to large spin splitting exhibiting in-plane Rashba spin polarizations. We also find that the interplay between the out-of-plane Zeeman- and in-plane Rashba spin-polarized states sensitively affects the spin lifetime, which can be effectively controlled by in-plane strain. In addition, the tunability of spin splitting using an external electric field is also demonstrated. Our study clarifies that the use of in-plane strain and an external electric field is effective for tuning the spin splitting and spin lifetime of the polar WSTe ML; thus, it is useful for designing spintronic devices.

Field tuning the g factor in InAs nanowire double quantum dots.

PubMed

Schroer, M D; Petersson, K D; Jung, M; Petta, J R

2011-10-21

We study the effects of magnetic and electric fields on the g factors of spins confined in a two-electron InAs nanowire double quantum dot. Spin sensitive measurements are performed by monitoring the leakage current in the Pauli blockade regime. Rotations of single spins are driven using electric-dipole spin resonance. The g factors are extracted from the spin resonance condition as a function of the magnetic field direction, allowing determination of the full g tensor. Electric and magnetic field tuning can be used to maximize the g-factor difference and in some cases altogether quench the electric-dipole spin resonance response, allowing selective single spin control. © 2011 American Physical Society

Toward Quantum Non-demolition of nitrogen-vacancy centers in diamond

NASA Astrophysics Data System (ADS)

Hodges, Jonathan; Jiang, Liang; Maze, Jeronimo; Lukin, Mikhail

2009-05-01

The nitrogen-vacancy color center (NVC) in diamond, which possesses a long-lived electronic spin (S=1) ground state with optical addressability, is a promising platform for quantum networks, single-photon sources, and nanoscale magnetometers. Here, we make use of a nuclear spin based quantum memory to demonstrate quantum non-demolition measurement of a solid-state spin qubit. By entangling the electron spin with a polarized carbon-13 spin (I=1/2) in the lattice, we have repeated optical measurement of the electron spin for the polarization lifetime of the nuclear spin. We show relative improvements in signal-to-noise of greater than 300%. These techniques can be used to improve the sensitivity of NVC magnetometers.

Nuclear magnetic resonance detection and spectroscopy of single proteins using quantum logic.

PubMed

Lovchinsky, I; Sushkov, A O; Urbach, E; de Leon, N P; Choi, S; De Greve, K; Evans, R; Gertner, R; Bersin, E; Müller, C; McGuinness, L; Jelezko, F; Walsworth, R L; Park, H; Lukin, M D

2016-02-19

Nuclear magnetic resonance spectroscopy is a powerful tool for the structural analysis of organic compounds and biomolecules but typically requires macroscopic sample quantities. We use a sensor, which consists of two quantum bits corresponding to an electronic spin and an ancillary nuclear spin, to demonstrate room temperature magnetic resonance detection and spectroscopy of multiple nuclear species within individual ubiquitin proteins attached to the diamond surface. Using quantum logic to improve readout fidelity and a surface-treatment technique to extend the spin coherence time of shallow nitrogen-vacancy centers, we demonstrate magnetic field sensitivity sufficient to detect individual proton spins within 1 second of integration. This gain in sensitivity enables high-confidence detection of individual proteins and allows us to observe spectral features that reveal information about their chemical composition. Copyright © 2016, American Association for the Advancement of Science.

Experimental Searches for Exotic Short-Range Forces Using Mechanical Oscillators

NASA Astrophysics Data System (ADS)

Weisman, Evan

Experimental searches for forces beyond gravity and electromagnetism at short range have attracted a great deal of attention over the last decade. In this thesis I describe the test mass development for two new experiments searching for forces below 1 mm. Both modify a previous experiment that used 1 kHz mechanical oscillators as test masses with a stiff conducting shield between them to suppress backgrounds, a promising technique for probing exceptionally small distances at the limit of instrumental thermal noise. To further reduce thermal noise, one experiment will use plated silicon test masses at cryogenic temperatures. The other experiment, which searches for spin-dependent interactions, will apply the spin-polarizable material Dy3Fe5O 12 to the test mass surfaces. This material exhibits orbital compensation of the magnetism associated with its intrinsic electron spin, minimizing magnetic backgrounds. Several plated silicon test mass prototypes were fabricated using photolithography (useful in both experiments), and spin-dependent materials were synthesized with a simple chemical recipe. Both silicon and spin-dependent test masses demonstrate the mechanical and magnetic properties necessary for sensitive experiments. I also describe sensitivity calculations of another proposed spin-dependent experiment, based on a modified search for the electron electric dipole moment, which show unprecedented sensitivity to exotic monopole-dipole forces. Inspired by a finite element model, a study attempting to maximize detector quality factor versus geometry is also presented, with experimental results so far not explained by the model.

Alternating Magnetic Field Controlled, Multifunctional Nano-Reservoirs: Intracellular Uptake and Improved Biocompatibility

NASA Astrophysics Data System (ADS)

Ghosh, Santaneel; Ghoshmitra, Somesree; Cai, Tong; Diercks, David R.; Mills, Nathaniel C.; Hynds, Dianna L.

2010-01-01

Biocompatible magnetic nanoparticles hold great therapeutic potential, but conventional particles can be toxic. Here, we report the synthesis and alternating magnetic field dependent actuation of a remotely controllable, multifunctional nano-scale system and its marked biocompatibility with mammalian cells. Monodisperse, magnetic nanospheres based on thermo-sensitive polymer network poly(ethylene glycol) ethyl ether methacrylate- co-poly(ethylene glycol) methyl ether methacrylate were synthesized using free radical polymerization. Synthesized nanospheres have oscillating magnetic field induced thermo-reversible behavior; exhibiting desirable characteristics comparable to the widely used poly- N-isopropylacrylamide-based systems in shrinkage plus a broader volumetric transition range. Remote heating and model drug release were characterized for different field strengths. Nanospheres containing nanoparticles up to an iron concentration of 6 mM were readily taken up by neuron-like PC12 pheochromocytoma cells and had reduced toxicity compared to other surface modified magnetic nanocarriers. Furthermore, nanosphere exposure did not inhibit the extension of cellular processes (neurite outgrowth) even at high iron concentrations (6 mM), indicating minimal negative effects in cellular systems. Excellent intracellular uptake and enhanced biocompatibility coupled with the lack of deleterious effects on neurite outgrowth and prior Food and Drug Administration (FDA) approval of PEG-based carriers suggest increased therapeutic potential of this system for manipulating axon regeneration following nervous system injury.

Synthesis and physicochemical characterization of chitin dihexanoate--A new biocompatible chitin derivative--In comparison to chitin dibutyrate.

PubMed

Skołucka-Szary, Karolina; Ramięga, Aleksandra; Piaskowska, Wanda; Janicki, Bartosz; Grala, Magdalena; Rieske, Piotr; Bartczak, Zbigniew; Piaskowski, Sylwester

2016-03-01

Chitin dihexanoate (DHCH) is the novel biocompatible and technologically friendly highly substituted chitin diester. Here we described optimization of DHCH and chitin dibutyrate (dibutyryl chitin, DBC) synthesis conditions (temperature and reaction time) to obtain desired polymers with high reaction yield, high substitution degree (close to 2) and appropriately high molecular weights. A two-step procedure, employing acidic anhydrides (hexanoic or butyric anhydride) as the acylation agent and methanesulfonic acid both as the catalyst and the reaction medium, was applied. Chemical structures of DBC and DHCH were confirmed by NMR ((1)H and (13)C) and IR investigations. Mechanical properties, thermogravimetric analysis, differential scanning calorimetry and biocompatibility (Neutral red uptake assay, Skin Sensitization and Irritation Tests) were assessed. Both polymers proved highly biocompatible (non-cytotoxic in vitro, non-irritating and non-allergic to skin) and soluble in several organic solvents (dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, acetone, ethanol and others). It is worth emphasizing that DHCH and DBC can be easily processed by solvent casting method and the salt-leaching method, what gives the opportunity to prepare highly porous structures, which can be further successfully applied as the material for wound dressings and scaffolds for tissue engineering. Copyright © 2015 Elsevier B.V. All rights reserved.

Practical method for transversely measuring the spin polarization of optically pumped alkali atoms

NASA Astrophysics Data System (ADS)

Ding, Zhichao; Yuan, Jie; Long, Xingwu

2018-06-01

A practical method to measure the spin polarization of optically pumped alkali atoms is demonstrated. In order to realize transverse measurement, the transverse spin component of spin-polarized alkali atoms is created by a rotating exciting magnetic field, and detected using the optical rotation of a near-resonant probe beam for realizing a high detection sensitivity. The dependency of the optical rotation on the spin polarization of 133Cs atoms is derived theoretically and verified experimentally. By changing the direction of the rotating magnetic field, we realize the transverse measurement of the spin polarization of 133Cs atoms in either ground-state hyperfine level.

Spin microscope based on optically detected magnetic resonance

DOEpatents

Berman, Gennady P [Los Alamos, NM; Chernobrod, Boris M [Los Alamos, NM

2010-06-29

The invention relates to scanning magnetic microscope which has a photoluminescent nanoprobe implanted in the tip apex of an atomic force microscope (AFM), a scanning tunneling microscope (STM) or a near-field scanning optical microscope (NSOM) and exhibits optically detected magnetic resonance (ODMR) in the vicinity of unpaired electron spins or nuclear magnetic moments in the sample material. The described spin microscope has demonstrated nanoscale lateral resolution and single spin sensitivity for the AFM and STM embodiments.

Spin microscope based on optically detected magnetic resonance

DOEpatents

Berman, Gennady P.; Chernobrod, Boris M.

2009-11-10

The invention relates to scanning magnetic microscope which has a photoluminescent nanoprobe implanted in the tip apex of an atomic force microscope (AFM), a scanning tunneling microscope (STM) or a near-field scanning optical microscope (NSOM) and exhibits optically detected magnetic resonance (ODMR) in the vicinity of impaired electron spins or nuclear magnetic moments in the sample material. The described spin microscope has demonstrated nanoscale lateral resolution and single spin sensitivity for the AFM and STM embodiments.

Spin microscope based on optically detected magnetic resonance

DOEpatents

Berman, Gennady P.; Chernobrod, Boris M.

2007-12-11

The invention relates to scanning magnetic microscope which has a photoluminescent nanoprobe implanted in the tip apex of an atomic force microscope (AFM), a scanning tunneling microscope (STM) or a near-field scanning optical microscope (NSOM) and exhibits optically detected magnetic resonance (ODMR) in the vicinity of unpaired electron spins or nuclear magnetic moments in the sample material. The described spin microscope has demonstrated nanoscale lateral resolution and single spin sensitivity for the AFM and STM embodiments.

Spin microscope based on optically detected magnetic resonance

DOEpatents

Berman, Gennady P [Los Alamos, NM; Chernobrod, Boris M [Los Alamos, NM

2010-07-13

The invention relates to scanning magnetic microscope which has a photoluminescent nanoprobe implanted in the tip apex of an atomic force microscope (AFM), a scanning tunneling microscope (STM) or a near-field scanning optical microscope (NSOM) and exhibits optically detected magnetic resonance (ODMR) in the vicinity of unpaired electron spins or nuclear magnetic moments in the sample material. The described spin microscope has demonstrated nanoscale lateral resolution and single spin sensitivity for the AFM and STM embodiments.

Spin microscope based on optically detected magnetic resonance

DOEpatents

Berman, Gennady P [Los Alamos, NM; Chernobrod, Boris M [Los Alamos, NM

2009-10-27

The invention relates to scanning magnetic microscope which has a photoluminescent nanoprobe implanted in the tip apex of an atomic force microscope (AFM), a scanning tunneling microscope (STM) or a near-field scanning optical microscope (NSOM) and exhibits optically detected magnetic resonance (ODMR) in the vicinity of unpaired electron spins or nuclear magnetic moments in the sample material. The described spin microscope has demonstrated nanoscale lateral resolution and single spin sensitivity for the AFM and STM embodiments.

Microenvironment-Sensitive Multimodal Contrast Agent for Prostate Cancer Diagnosis

DTIC Science & Technology

2014-10-01

which serve as a contrast agent for Magnetic Resonance Imaging (MRI), coated with a biopolymer (i.e. starch ) to improve biocompatibility, and...size stability (i.e. resisted aggregation) and lower protein binding than the unmodified MNP. The MNPs were also incubated for varying time periods with

Nonlinear spin conductance of yttrium iron garnet thin films driven by large spin-orbit torque

NASA Astrophysics Data System (ADS)

Thiery, N.; Draveny, A.; Naletov, V. V.; Vila, L.; Attané, J. P.; Beigné, C.; de Loubens, G.; Viret, M.; Beaulieu, N.; Ben Youssef, J.; Demidov, V. E.; Demokritov, S. O.; Slavin, A. N.; Tiberkevich, V. S.; Anane, A.; Bortolotti, P.; Cros, V.; Klein, O.

2018-02-01

We report high power spin transfer studies in open magnetic geometries by measuring the spin conductance between two nearby Pt wires deposited on top of an epitaxial yttrium iron garnet thin film. Spin transport is provided by propagating spin waves that are generated and detected by direct and inverse spin Hall effects. We observe a crossover in spin conductance from a linear transport dominated by exchange magnons (low current regime) to a nonlinear transport dominated by magnetostatic magnons (high current regime). The latter are low-damping magnetic excitations, located near the spectral bottom of the magnon manifold, with a sensitivity to the applied magnetic field. This picture is supported by microfocus Brillouin light-scattering spectroscopy. Our findings could be used for the development of controllable spin conductors by variation of relatively weak magnetic fields.

Moderate MAS enhances local (1)H spin exchange and spin diffusion.

PubMed

Roos, Matthias; Micke, Peter; Saalwächter, Kay; Hempel, Günter

2015-11-01

Proton NMR spin-diffusion experiments are often combined with magic-angle spinning (MAS) to achieve higher spectral resolution of solid samples. Here we show that local proton spin diffusion can indeed become faster at low (<10 kHz) spinning rates as compared to static conditions. Spin diffusion under static conditions can thus be slower than the often referred value of 0.8 nm(2)/ms, which was determined using slow MAS (Clauss et al., 1993). The enhancement of spin diffusion by slow MAS relies on the modulation of the orientation-dependent dipolar couplings during sample rotation and goes along with transient level crossings in combination with dipolar truncation. The experimental finding and its explanation is supported by density matrix simulations, and also emphasizes the sensitivity of spin diffusion to the local coupling topology. The amplification of spin diffusion by slow MAS cannot be explained by any model based on independent spin pairs; at least three spins have to be considered. Copyright © 2015 Elsevier Inc. All rights reserved.

Schemes of detecting nuclear spin correlations by dynamical decoupling based quantum sensing

NASA Astrophysics Data System (ADS)

Ma, Wen-Long Ma; Liu, Ren-Bao

Single-molecule sensitivity of nuclear magnetic resonance (NMR) and angstrom resolution of magnetic resonance imaging (MRI) are the highest challenges in magnetic microscopy. Recent development in dynamical decoupling (DD) enhanced diamond quantum sensing has enabled NMR of single nuclear spins and nanoscale NMR. Similar to conventional NMR and MRI, current DD-based quantum sensing utilizes the frequency fingerprints of target nuclear spins. Such schemes, however, cannot resolve different nuclear spins that have the same noise frequency or differentiate different types of correlations in nuclear spin clusters. Here we show that the first limitation can be overcome by using wavefunction fingerprints of target nuclear spins, which is much more sensitive than the ''frequency fingerprints'' to weak hyperfine interaction between the targets and a sensor, while the second one can be overcome by a new design of two-dimensional DD sequences composed of two sets of periodic DD sequences with different periods, which can be independently set to match two different transition frequencies. Our schemes not only offer an approach to breaking the resolution limit set by ''frequency gradients'' in conventional MRI, but also provide a standard approach to correlation spectroscopy for single-molecule NMR.

Silk-fibronectin protein alloy fibres support cell adhesion and viability as a high strength, matrix fibre analogue

NASA Astrophysics Data System (ADS)

Jacobsen, Matthew M.; Li, David; Gyune Rim, Nae; Backman, Daniel; Smith, Michael L.; Wong, Joyce Y.

2017-04-01

Silk is a natural polymer with broad utility in biomedical applications because it exhibits general biocompatibility and high tensile material properties. While mechanical integrity is important for most biomaterial applications, proper function and integration also requires biomaterial incorporation into complex surrounding tissues for many physiologically relevant processes such as wound healing. In this study, we spin silk fibroin into a protein alloy fibre with whole fibronectin using wet spinning approaches in order to synergize their respective strength and cell interaction capabilities. Results demonstrate that silk fibroin alone is a poor adhesive surface for fibroblasts, endothelial cells, and vascular smooth muscle cells in the absence of serum. However, significantly improved cell attachment is observed to silk-fibronectin alloy fibres without serum present while not compromising the fibres’ mechanical integrity. Additionally, cell viability is improved up to six fold on alloy fibres when serum is present while migration and spreading generally increase as well. These findings demonstrate the utility of composite protein alloys as inexpensive and effective means to create durable, biologically active biomaterials.

Laser microjoining of dissimilar and biocompatible materials

NASA Astrophysics Data System (ADS)

Bauer, Ingo; Russek, Ulrich A.; Herfurth, Hans J.; Witte, Reiner; Heinemann, Stefan; Newaz, Golam; Mian, A.; Georgiev, D.; Auner, Gregory W.

2004-07-01

Micro-joining and hermetic sealing of dissimilar and biocompatible materials is a critical issue for a broad spectrum of products such as micro-electronics, micro-optical and biomedical products and devices. Today, biocompatible titanium is widely applied as a material for orthopedic implants as well as for the encapsulation of implantable devices such as pacemakers, defibrillators, and neural stimulator devices. Laser joining is the process of choice to hermetically seal such devices. Laser joining is a contact-free process, therefore minimizing mechanical load on the parts to be joined and the controlled heat input decreases the potential for thermal damage to the highly sensitive components. Laser joining also offers flexibility, shorter processing time and higher quality. However, novel biomedical products, in particular implantable microsystems currently under development, pose new challenges to the assembly and packaging process based on the higher level of integration, the small size of the device's features, and the type of materials and material combinations. In addition to metals, devices will also include glass, ceramic and polymers as biocompatible building materials that must be reliably joined in similar and dissimilar combinations. Since adhesives often lack long-term stability or do not meet biocompatibility requirements, new joining techniques are needed to address these joining challenges. Localized laser joining provides promising developments in this area. This paper describes the latest achievements in micro-joining of metallic and non-metallic materials with laser radiation. The focus is on material combinations of metal-polymer, polymer-glass, metal-glass and metal-ceramic using CO2, Nd:YAG and diode laser radiation. The potential for applications in the biomedical sector will be demonstrated.

Sensitive spin detection using an on-chip SQUID-waveguide resonator

NASA Astrophysics Data System (ADS)

Yue, G.; Chen, L.; Barreda, J.; Bevara, V.; Hu, L.; Wu, L.; Wang, Z.; Andrei, P.; Bertaina, S.; Chiorescu, I.

2017-11-01

Precise detection of spin resonance is of paramount importance to achieve coherent spin control in quantum computing. We present a setup for spin resonance measurements, which uses a dc-SQUID flux detector coupled to an antenna from a coplanar waveguide. The SQUID and the waveguide are fabricated from a 20 nm Nb thin film, allowing high magnetic field operation with the field applied parallel to the chip. We observe a resonance signal between the first and third excited states of Gd spins S = 7/2 in a CaWO4 crystal, relevant for state control in multi-level systems.

Open Heisenberg chain under boundary fields: A magnonic logic gate

NASA Astrophysics Data System (ADS)

Landi, Gabriel T.; Karevski, Dragi

2015-05-01

We study the spin transport in the quantum Heisenberg spin chain subject to boundary magnetic fields and driven out of equilibrium by Lindblad dissipators. An exact solution is given in terms of matrix product states, which allows us to calculate exactly the spin current for any chain size. It is found that the system undergoes a discontinuous spin-valve-like quantum phase transition from ballistic to subdiffusive spin current, depending on the value of the boundary fields. Thus, the chain behaves as an extremely sensitive magnonic logic gate operating with the boundary fields as the base element.

Increased sensitivity of spin noise spectroscopy using homodyne detection in n -doped GaAs

NASA Astrophysics Data System (ADS)

Petrov, M. Yu.; Kamenskii, A. N.; Zapasskii, V. S.; Bayer, M.; Greilich, A.

2018-03-01

We implement the homodyne detection scheme for an increase in the polarimetric sensitivity in spin noise spectroscopy. Controlling the laser intensity of the local oscillator, which is guided around the sample and does not perturb the measured spin system, we are able to improve the signal-to-noise ratio. The opportunity for additional amplification of the measured signal strength allows us to reduce the probe laser intensity incident on the sample and therefore to approach the nonperturbative regime. The efficiency of this scheme with signal enhancement by more than a factor of 3 at low probe powers is demonstrated on bulk n -doped GaAs, where the reduced electron-spin relaxation rate is shown experimentally. Additionally, the control of the optical phase provides us with the possibility to switch between measuring Faraday rotation and ellipticity without changes in the optical setup.

Porosity characterization of biodegradable porous poly (L-lactic acid) electrospun nanofibers

NASA Astrophysics Data System (ADS)

Valipouri, Afsaneh; Gharehaghaji, Ali Akbar; Alirezazadeh, Azam; Ravandi, Seyed Abdolkarim Hosseini

2017-12-01

Poly-L lactic acid (PLLA) is one of the mostly used fibers in biomedical applications as a biodegradable and biocompatible material. Porosity and fiber diameter distribution are governing factors that determine the performance of nanofibers. Present work aims at investigating the process parameters that are affecting porosity and diameter distribution of PLLA nanofibers. PLLA nanofibers were fabricated through electrospinning method using the solution of PLLA polymer/dichloromethane (DCM). Nanofibers with various fiber diameter distribution and porosity were made by changing of process parameters such as spinning distance (5, 10 and 15 cm), voltage (11 and 15 kV), solution concentration (10, 11 and 12 wt%) and feeding rate (0.3, 0.4 and 0.7 ml h-1). Image processing techniques (with Matlab R2017), surface analysis (with Mountainsmap7) and diameter distribution analysis (with Measurement software) were used to examine surface morphology of samples. The results showed that the fiber diameter distribution becomes wider with increasing the applied voltage and reducing the spinning distance. In the other hand, coarse fibers possessed larger pores while having irregular and fewer pores in comparison to fine fibers. The most uniform nano-web with high porous nanofibers was attained by the choice of the process parameters at the voltage of 11 kV, spinning distance of 15 cm, feeding rate of 0.4 ml h-1 and solution concentration of 10 wt%.

Standard Biocompatibility Studies Do Not Predict All Effects of PVA/CMC Anti-Adhesive Gel in vivo.

PubMed

Freytag, Christiane; Odermatt, Erich K

2016-01-01

PVA/CMC (polyvinyl alcohol/carboxymethyl cellulose) hydrogel fulfills various physiochemical properties required for an adhesion barrier and has shown good anti-adhesion properties in previous in vivo studies. In this investigation, we assessed the in vitro and in vivo biocompatibility of PVA/CMC gel and compared this to the functionality and promotion of wound healing for two surgical indications. Standardized ISO10993 in vitro and in vivo biocompatibility studies, comprising cytotoxicity, genotoxicity, acute systemic toxicity, delayed contact and maximization sensitization test, intracutaneous reactivity and local muscle implantation, were performed on PVA/CMC gel. In the functional studies, PVA/CMC gel was applied - on the one hand - to a rabbit abdominal wall model enforced with a polypropylene mesh for testing the anti-adhesion properties and - on the other hand - to an end- to-end anastomosis model that was selected for surveying potential influences of different dosages of PVA/CMC gel on anastomotic wound healing. The ISO10993 methods indicated generally good biocompatibility properties, such as the absence of cytotoxic and mutagenic effects as well as no signs of systemic toxicity and sensitization potentials. No irritation effects were observed after the intracutaneous injection of lipophilic PVA/CMC sesame oil extract. However, the injection of hydrophilic PVA/CMC physiologic saline extract induced slight irritation. Following rabbit muscle implantation of the PVA membrane for 2, 4, 12, 26 and 52 weeks, a slight irritant effect was observed at 12 weeks due to the peak of phagocytosis. In the functionality tests, PVA/CMC gel showed good anti-adhesive effects in the abdominal wall model enforced with the mesh, with significantly lower and less tense adhesions compared to the untreated control. However, moderate signs of inflammation, especially in the spleen were observed after the intra-abdominal implantation of 3.3 ml PVA/CMC gel per kg body weight. In the end-to-end anastomosis model, PVA/CMC gel had no influence on wound healing. For dosages of 1-6 ml gel per treatment, no signs of intestinal leaks were detected, and tensile strength was equal to that of the untreated control, but again more moderate signs of inflammation in the spleen were observed at a dosage >3 ml. Comparing the standardized ISO10993 methods, anti-adhesive PVA/CMC gel displays good biocompatibility. However, those methods do not seem to be sensitive enough because the rabbit abdominal wall and the end-to-end anastomosis models display more effects with respect to the dosage and routes of the intra-abdominal resorption of PVA/CMC gel - with the recommended <2 ml PVA/CMC gel per kg body weight as a secure dosage. © 2016 S. Karger AG, Basel.

Validation of intensive care unit-acquired infection surveillance in the Italian SPIN-UTI network.

PubMed

Masia, M D; Barchitta, M; Liperi, G; Cantù, A P; Alliata, E; Auxilia, F; Torregrossa, V; Mura, I; Agodi, A

2010-10-01

Validity is one of the most critical factors concerning surveillance of nosocomial infections (NIs). This article describes the first validation study of the Italian Nosocomial Infections Surveillance in Intensive Care Units (ICUs) project (SPIN-UTI) surveillance data. The objective was to validate infection data and thus to determine the sensitivity, specificity, and positive and negative predictive values of NI data reported on patients in the ICUs participating in the SPIN-UTI network. A validation study was performed at the end of the surveillance period. All medical records including all clinical and laboratory data were reviewed retrospectively by the trained physicians of the validation team and a positive predictive value (PPV), a negative predictive value (NPV), sensitivity and specificity were calculated. Eight ICUs (16.3%) were randomly chosen from all 49 SPIN-UTI ICUs for the validation study. In total, the validation team reviewed 832 patient charts (27.3% of the SPIN-UTI patients). The PPV was 83.5% and the NPV was 97.3%. The overall sensitivity was 82.3% and overall specificity was 97.2%. Over- and under-reporting of NIs were related to misinterpretation of the case definitions and deviations from the protocol despite previous training and instructions. The results of this study are useful to identify methodological problems within a surveillance system and have been used to plan retraining for surveillance personnel and to design and implement the second phase of the SPIN-UTI project. Copyright 2010 The Hospital Infection Society. Published by Elsevier Ltd. All rights reserved.

Optically Induced Nuclear Spin Polarization in the Quantum Hall Regime: The Effect of Electron Spin Polarization through Exciton and Trion Excitations.

PubMed

Akiba, K; Kanasugi, S; Yuge, T; Nagase, K; Hirayama, Y

2015-07-10

We study nuclear spin polarization in the quantum Hall regime through the optically pumped electron spin polarization in the lowest Landau level. The nuclear spin polarization is measured as a nuclear magnetic field B(N) by means of the sensitive resistive detection. We find the dependence of B(N) on the filling factor nonmonotonic. The comprehensive measurements of B(N) with the help of the circularly polarized photoluminescence measurements indicate the participation of the photoexcited complexes, i.e., the exciton and trion (charged exciton), in nuclear spin polarization. On the basis of a novel estimation method of the equilibrium electron spin polarization, we analyze the experimental data and conclude that the filling factor dependence of B(N) is understood by the effect of electron spin polarization through excitons and trions.

Optimized quantum sensing with a single electron spin using real-time adaptive measurements.

PubMed

Bonato, C; Blok, M S; Dinani, H T; Berry, D W; Markham, M L; Twitchen, D J; Hanson, R

2016-03-01

Quantum sensors based on single solid-state spins promise a unique combination of sensitivity and spatial resolution. The key challenge in sensing is to achieve minimum estimation uncertainty within a given time and with high dynamic range. Adaptive strategies have been proposed to achieve optimal performance, but their implementation in solid-state systems has been hindered by the demanding experimental requirements. Here, we realize adaptive d.c. sensing by combining single-shot readout of an electron spin in diamond with fast feedback. By adapting the spin readout basis in real time based on previous outcomes, we demonstrate a sensitivity in Ramsey interferometry surpassing the standard measurement limit. Furthermore, we find by simulations and experiments that adaptive protocols offer a distinctive advantage over the best known non-adaptive protocols when overhead and limited estimation time are taken into account. Using an optimized adaptive protocol we achieve a magnetic field sensitivity of 6.1 ± 1.7 nT Hz(-1/2) over a wide range of 1.78 mT. These results open up a new class of experiments for solid-state sensors in which real-time knowledge of the measurement history is exploited to obtain optimal performance.

Optimized quantum sensing with a single electron spin using real-time adaptive measurements

NASA Astrophysics Data System (ADS)

Bonato, C.; Blok, M. S.; Dinani, H. T.; Berry, D. W.; Markham, M. L.; Twitchen, D. J.; Hanson, R.

2016-03-01

Quantum sensors based on single solid-state spins promise a unique combination of sensitivity and spatial resolution. The key challenge in sensing is to achieve minimum estimation uncertainty within a given time and with high dynamic range. Adaptive strategies have been proposed to achieve optimal performance, but their implementation in solid-state systems has been hindered by the demanding experimental requirements. Here, we realize adaptive d.c. sensing by combining single-shot readout of an electron spin in diamond with fast feedback. By adapting the spin readout basis in real time based on previous outcomes, we demonstrate a sensitivity in Ramsey interferometry surpassing the standard measurement limit. Furthermore, we find by simulations and experiments that adaptive protocols offer a distinctive advantage over the best known non-adaptive protocols when overhead and limited estimation time are taken into account. Using an optimized adaptive protocol we achieve a magnetic field sensitivity of 6.1 ± 1.7 nT Hz-1/2 over a wide range of 1.78 mT. These results open up a new class of experiments for solid-state sensors in which real-time knowledge of the measurement history is exploited to obtain optimal performance.

Culture materials affect ex vivo expansion of hematopoietic progenitor cells.

PubMed

LaIuppa, J A; McAdams, T A; Papoutsakis, E T; Miller, W M

1997-09-05

Ex vivo expansion of hematopoietic cells is important for applications such as cancer treatment, gene therapy, and transfusion medicine. While cell culture systems are widely used to evaluate the biocompatibility of materials for implantation, the ability of materials to support proliferation of primary human cells in cultures for reinfusion into patients has not been addressed. We screened a variety of commercially available polymer (15 types), metal (four types), and glass substrates for their ability to support expansion of hematopoietic cells when cultured under conditions that would be encountered in a clinical setting. Cultures of peripheral blood (PB) CD34+ cells and mononuclear cells (MNC) were evaluated for expansion of total cells and colony-forming unit-granulocyte monocyte (CFU-GM; progenitors committed to the granulocyte and/or monocyte lineage). Human hematopoietic cultures in serum-free medium were found to be extremely sensitive to the substrate material. The only materials tested that supported expansion at or near the levels of polystyrene were tissue culture polystyrene, Teflon perfluoroalkoxy, Teflon fluorinated ethylene propylene, cellulose acetate, titanium, new polycarbonate, and new polymethylpentene. MNC were less sensitive to the substrate materials than the primitive CD34+ progenitors, although similar trends were seen for expansion of the two cell populations on the substrates tested. CFU-GM expansion was more sensitive to substrate materials than was total cell expansion. The detrimental effects of a number of the materials on hematopoietic cultures appear to be caused by protein adsorption and/or leaching of toxins. Factors such as cleaning, sterilization, and reuse significantly affected the performance of some materials as culture substrates. We also used PB CD34+ cell cultures to examine the biocompatibility of gas-permeable cell culture and blood storage bags and several types of tubing commonly used with biomedical equipment. While many of the culture bag materials gave satisfactory results, all of the tubing materials severely inhibited total cell and CFU-GM expansion. Taken together, our results show that many materials approved for blood contact or considered biocompatible are not suitable for use with hematopoietic cells cultured in serum-free medium. As hematopoietic cultures are scaled up for a variety of clinical applications, it will be essential to carefully examine the biocompatibility of all materials involved.

Angstrom-Resolution Magnetic Resonance Imaging of Single Molecules via Wave-Function Fingerprints of Nuclear Spins

NASA Astrophysics Data System (ADS)

Ma, Wen-Long; Liu, Ren-Bao

2016-08-01

Single-molecule sensitivity of nuclear magnetic resonance (NMR) and angstrom resolution of magnetic resonance imaging (MRI) are the highest challenges in magnetic microscopy. Recent development in dynamical-decoupling- (DD) enhanced diamond quantum sensing has enabled single-nucleus NMR and nanoscale NMR. Similar to conventional NMR and MRI, current DD-based quantum sensing utilizes the "frequency fingerprints" of target nuclear spins. The frequency fingerprints by their nature cannot resolve different nuclear spins that have the same noise frequency or differentiate different types of correlations in nuclear-spin clusters, which limit the resolution of single-molecule MRI. Here we show that this limitation can be overcome by using "wave-function fingerprints" of target nuclear spins, which is much more sensitive than the frequency fingerprints to the weak hyperfine interaction between the targets and a sensor under resonant DD control. We demonstrate a scheme of angstrom-resolution MRI that is capable of counting and individually localizing single nuclear spins of the same frequency and characterizing the correlations in nuclear-spin clusters. A nitrogen-vacancy-center spin sensor near a diamond surface, provided that the coherence time is improved by surface engineering in the near future, may be employed to determine with angstrom resolution the positions and conformation of single molecules that are isotope labeled. The scheme in this work offers an approach to breaking the resolution limit set by the "frequency gradients" in conventional MRI and to reaching the angstrom-scale resolution.

Spin decoherence of InAs surface electrons by transition metal ions

NASA Astrophysics Data System (ADS)

Zhang, Yao; Soghomonian, V.; Heremans, J. J.

2018-04-01

Spin interactions between a two-dimensional electron system at the InAs surface and transition metal ions, Fe3 +, Co2 +, and Ni2 +, deposited on the InAs surface, are probed by antilocalization measurements. The spin-dependent quantum interference phenomena underlying the quantum transport phenomenon of antilocalization render the technique sensitive to the spin states of the transition metal ions on the surface. The experiments yield data on the magnitude and temperature dependence of the electrons' inelastic scattering rates, spin-orbit scattering rates, and magnetic spin-flip rates as influenced by Fe3 +, Co2 +, and Ni2 +. A high magnetic spin-flip rate is shown to mask the effects of spin-orbit interaction, while the spin-flip rate is shown to scale with the effective magnetic moment of the surface species. The spin-flip rates and their dependence on temperature yield information about the spin states of the transition metal ions at the surface, and in the case of Co2 + suggest either a spin transition or formation of a spin-glass system.

Low Young's modulus Ti-based porous bulk glassy alloy without cytotoxic elements.

PubMed

Nicoara, M; Raduta, A; Parthiban, R; Locovei, C; Eckert, J; Stoica, M

2016-05-01

A new a biocompatible Ti42Zr40Ta3Si15 (atomic %) porous bulk glassy alloy was produced by combination of rapid solidification and powder metallurgy techniques. Amorphous alloy ribbons were fabricated by melt spinning, i.e. extremely fast quenching the molten alloy with 10(6)K/s from T=1973K down to room temperature. The ribbons were then cryo-milled at liquid nitrogen temperature in order to produce powder, which was subsequently hot pressed. The resulting thick pellets have a porosity of about 14vol%, a high compression strength of 337MPa and a Young's modulus of about E=52GPa, values very close to those characteristic of cortical bone. Moreover, the morphology of the samples is very similar to that of cortical bone. The biocompatibility, which is due to the absence of any toxic element in the chemical composition, together with the suitable mechanical behavior, make these samples promising for orthopedic and dentistry applications. Ti-based alloys are nowadays the standard solution for biomedical implants. However, both the conventional crystalline and amorphous alloys have higher rigidity as the human bone, leading to the damage of the bone at the interface, and contains harmful elements like vanadium, aluminum, nickel or beryllium. The hierarchical porous structures based on glassy alloys with biocompatible elements is a much better alternative. This work presents for the first time the manufacturing of such porous bodies starting from Ti-based amorphous alloy ribbons, which contains only non-harmful elements. The morphology and the compressive mechanical properties of these new products are analyzed in regard with those characteristic to the cortical bone. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Screening for social phobia in medical in- and outpatients with the German version of the Social Phobia Inventory (SPIN).

PubMed

Sosic, Z; Gieler, U; Stangier, U

2008-06-01

To evaluate the German version of the Social Phobia Inventory (SPIN) as a screening device and to report corresponding cut-off scores for different populations. In Study 1, 2043 subjects from a representative sample completed the SPIN. Cut-off values were established on the basis of means and standard deviations. In Study 2, different aspects of validity were examined in a clinical sample comprising 164 subjects, including social phobic individuals, individuals with other anxiety disorders and depression, and non-clinical control subjects. Internal consistency was evaluated. Convergent and divergent validity were explored using several established measures. Finally, the sensitivity and specificity of the German SPIN with regard to social anxiety classification were investigated by means of receiver operating characteristics (ROC) analyses. In Study 1, mean scores and standard deviations were used to determine cut-off scores for the German SPIN. In Study 2, excellent internal consistency and good convergent and divergent validity were obtained. ROC analyses revealed that the German SPIN performed well in discriminating between social phobic individuals on the one hand and psychiatric and non-psychiatric controls on the other. A cut-off score of 25 represented the best balance between sensitivity and specificity. Comparable to the original version, the German SPIN demonstrates solid psychometric properties and shows promise as an economic, reliable, and valid screening device.

Multiple acquisitions via sequential transfer of orphan spin polarization (MAeSTOSO): How far can we push residual spin polarization in solid-state NMR?

NASA Astrophysics Data System (ADS)

Gopinath, T.; Veglia, Gianluigi

2016-06-01

Conventional multidimensional magic angle spinning (MAS) solid-state NMR (ssNMR) experiments detect the signal arising from the decay of a single coherence transfer pathway (FID), resulting in one spectrum per acquisition time. Recently, we introduced two new strategies, namely DUMAS (DUal acquisition Magic Angle Spinning) and MEIOSIS (Multiple ExperIments via Orphan SpIn operatorS), that enable the simultaneous acquisitions of multidimensional ssNMR experiments using multiple coherence transfer pathways. Here, we combined the main elements of DUMAS and MEIOSIS to harness both orphan spin operators and residual polarization and increase the number of simultaneous acquisitions. We show that it is possible to acquire up to eight two-dimensional experiments using four acquisition periods per each scan. This new suite of pulse sequences, called MAeSTOSO for Multiple Acquisitions via Sequential Transfer of Orphan Spin pOlarization, relies on residual polarization of both 13C and 15N pathways and combines low- and high-sensitivity experiments into a single pulse sequence using one receiver and commercial ssNMR probes. The acquisition of multiple experiments does not affect the sensitivity of the main experiment; rather it recovers the lost coherences that are discarded, resulting in a significant gain in experimental time. Both merits and limitations of this approach are discussed.

Biocompatibility and light transmission of liposomal lenses.

PubMed

Danion, Anne; Doillon, Charles J; Giasson, Claude J; Djouahra, Saliha; Sauvageau, Patrick; Paradis, Renée; Vermette, Patrick

2007-10-01

To validate the biocompatibility and transmittance properties of contact lenses bearing intact liposomes. These liposomal lenses loaded with therapeutics can be used as ophthalmic drug delivery systems. The biocompatibility of soft contact lenses, coated with liposomes was evaluated through in vitro direct and indirect cytocompatibility assays on human corneal epithelial cells, on reconstructed human corneas and on ex vivo rabbit corneas. The direct and indirect transmission spectra of liposome-covered lenses were also evaluated to test if they transmit all wavelengths of the ultraviolet-visible spectrum, to thereby fulfill their optical function, without gross alteration of the colors perception and with a minimum of light dispersion. Contact lenses bearing layers of stable liposomes did not induce any significant changes in cell viability and in cell growth, compared with lenses bearing no liposome. Elution assays revealed that no cytotoxic compound leaks from the lenses whether bearing liposomes or not. Histological analyses of reconstructed human corneas and ex vivo rabbit corneas directly exposed to liposomal lenses revealed neither alteration to the cell nor to the tissue structures. Contact lenses bearing layers of liposomes did not significantly affect light transmission compared with control lenses without liposome at the wavelength of maximal photopic sensitivity, i.e., 550 nm. In addition, the contact lenses afford more eye protection in the ultraviolet spectrum, compared with the control lenses. Liposomal contact lenses are biocompatible and their transmittance properties are not affected in the visible light range.

In vitro and in vivo biological characterization of poly(lactic acid) fiber scaffolds synthesized by air jet spinning.

PubMed

Granados-Hernández, Marco Vladimir; Serrano-Bello, Janeth; Montesinos, Juan José; Alvarez-Gayosso, Carlos; Medina-Velázquez, Luis Alberto; Alvarez-Fregoso, Octavio; Alvarez-Perez, Marco Antonio

2017-11-30

Poly(lactic acid) (PLA) is one of the most promising renewable and biodegradable polymers for mimic extracellular matrix for tissue engineering applications. In this work, PLA spun membrane scaffold were successfully prepared by air jet spinning technology. Morphology, mechanical properties, in vitro biocompatibility, and in vitro and in vivo degradation of PLA fibrous scaffold were characterized by X-ray diffraction, Fourier Transform Infrared, and scanning electron microscope (SEM). Morphological results assessed by SEM analyses indicated that PLA scaffolds possessed an average fiber diameter of approximately 0.558 ± 0.141 µm for 7% w/v of PLA and approximately 0.647 ± 0.137 µm for 10% w/v. Interestingly, our results showed that the nanofiber size of PLA scaffold allow structural stability after 100 days of in vitro degradation in Ringer solution where the average fiber diameter were of approximately 0.633 ± 0.147 µm for 7% w/v and approximately 0.645 ± 0.140 µm for 10% w/v of PLA. Mechanical properties of PLA fibers scaffold after in vitro degradation showed decrease in terms of flexibility elongation, and less energy was needed to achieve maximal elastic deformation. The fiber size exerts an influence on the biological response of human Bone Marrow Mesenchymal Stromal Cells as confirmed by MTT assay after 9 days of cell culture and the in vivo degradation assay of 7% w/v and 10% w/v of PLA scaffold, did not demonstrate evidence of toxicity with a mild inflammatory respond. In conclusion, airbrushing technology promises to be a viable and attractive alternative technique for producing a biocompatible PLA nanofiber scaffold that could be considered for tissue engineering regeneration. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2017. © 2017 Wiley Periodicals, Inc.

Sensitivity enhancements in MQ-MAS NMR of spin-5/2 nuclei using modulated rf mixing pulses

NASA Astrophysics Data System (ADS)

Vosegaard, Thomas; Massiot, Dominique; Grandinetti, Philip J.

2000-08-01

An X- overlineX pulse train with stepped modulation frequency was employed to enhance the multiple-quantum to single-quantum coherence transfer in the mixing period of the multiple-quantum magic-angle spinning (MQ-MAS) experiment for spin I=5/2 nuclei. Two MQ-MAS pulse sequences employing this mixing scheme for the triple-to-single and quintuple-to-single quantum coherence transfers have been designed and their performance is demonstrated for 27Al on samples of NaSi 3AlO 8 and 9Al 2O 3·2B 2O 3 . Compared to the standard single-pulse mixing sequences, the sensitivity is approximately doubled in the present experiments.

Study of translational dynamics in molten polymer by variation of gradient pulse-width of PGSE.

PubMed

Stepišnik, Janez; Lahajnar, Gojmir; Zupančič, Ivan; Mohorič, Aleš

2013-11-01

Pulsed gradient spin echo is a method of measuring molecular translation. Changing Δ makes it sensitive to diffusion spectrum. Spin translation effects the buildup of phase structure during the application of gradient pulses as well. The time scale of the self-diffusion measurement shortens if this is taken into account. The method of diffusion spectrometry with variable δ is also less sensitive to artifacts caused by spin relaxation and internal gradient fields. Here the method is demonstrated in the case of diffusion spectrometry of molten polyethylene. The results confirm a model of constraint release in a system of entangled polymer chains as a sort of tube Rouse motion. Copyright © 2013 Elsevier Inc. All rights reserved.

CdS/CdSe quantum dot shell decorated vertical ZnO nanowire arrays by spin-coating-based SILAR for photoelectrochemical cells and quantum-dot-sensitized solar cells.

PubMed

Zhang, Ran; Luo, Qiu-Ping; Chen, Hong-Yan; Yu, Xiao-Yun; Kuang, Dai-Bin; Su, Cheng-Yong

2012-04-23

A CdS/CdSe composite shell is assembled onto the surface of ZnO nanowire arrays with a simple spin-coating-based successive ionic layer adsorption and reaction method. The as-prepared photoelectrode exhibit a high photocurrent density in photoelectrochemical cells and also generates good power conversion efficiency in quantum-dot-sensitized solar cells. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

[Validation of the portuguese version of the Mini-Social Phobia Inventory (Mini-SPIN)].

PubMed

D'El Rey, Gustavo José Fonseca; Matos, Cláudia Wilmor

2009-01-01

Social phobia (also known as social anxiety disorder) is a severe mental disorder that brings distress and disability. The aim of this study was validate to the Portuguese language the Mini-Social Phobia Inventory (Mini-SPIN) in a populational sample. We performed a discriminative validity study of the Mini-SPIN in a sample of 644 subjects (Mini-SPIN positive group: n = 218 and control/negative group: n = 426) of a study of anxiety disorders' prevalence in the city of Santo André-SP. The Portuguese version of the Mini-SPIN (with score of 6 points, suggested in the original English version) demonstrated a sensitivity of 95.0%, specificity of 80.3%, positive predictive value of 52.8%, negative predictive value of 98.6% and incorrect classification rate of 16.9%. With score of 7 points, was observed an increase in the specificity and positive predictive value (88.6% and 62.7%), while the sensitivity and negative predictive value (84.8% and 96.2%) remained high. The Portuguese version of the Mini-SPIN showed satisfactory psychometric qualities in terms of discriminative validity. In this study, the cut-off of 7, was considered to be the most suitable to screening of the generalized social phobia.

Spin Seebeck devices using local on-chip heating

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Stephen M.; Fradin, Frank Y.; Hoffman, Jason

2015-05-07

A micro-patterned spin Seebeck device is fabricated using an on-chip heater. Current is driven through a Au heater layer electrically isolated from a bilayer consisting of Fe3O4 (insulating ferrimagnet) and a spin detector layer. It is shown that through this method it is possible to measure the longitudinal spin Seebeck effect (SSE) for small area magnetic devices, equivalent to traditional macroscopic SSE experiments. Using a lock-in detection technique, it is possible to more sensitively characterize both the SSE and the anomalous Nernst effect (ANE), as well as the inverse spin Hall effect in various spin detector materials. By using themore » spin detector layer as a thermometer, we can obtain a value for the temperature gradient across the device. These results are well matched to values obtained through electromagnetic/thermal modeling of the device structure and with large area spin Seebeck measurements.« less

Spin Seebeck devices using local on-chip heating

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Stephen M., E-mail: swu@anl.gov; Fradin, Frank Y.; Hoffman, Jason

2015-05-07

A micro-patterned spin Seebeck device is fabricated using an on-chip heater. Current is driven through a Au heater layer electrically isolated from a bilayer consisting of Fe{sub 3}O{sub 4} (insulating ferrimagnet) and a spin detector layer. It is shown that through this method it is possible to measure the longitudinal spin Seebeck effect (SSE) for small area magnetic devices, equivalent to traditional macroscopic SSE experiments. Using a lock-in detection technique, it is possible to more sensitively characterize both the SSE and the anomalous Nernst effect (ANE), as well as the inverse spin Hall effect in various spin detector materials. Bymore » using the spin detector layer as a thermometer, we can obtain a value for the temperature gradient across the device. These results are well matched to values obtained through electromagnetic/thermal modeling of the device structure and with large area spin Seebeck measurements.« less

Procalcitonin as a marker of micro-inflammation in hemodialysis.

PubMed

Conti, Giovanni; Amore, Alessandro; Chiesa, Monica; Mancuso, Domenico; Cirina, Paola; Mengozzi, Giulio; Santoro, Antonio; Coppo, Rosanna

2005-01-01

In searching for a rapid and sensitive test to detect micro-inflammation in patients on hemodialysis (HD), we measured serum procalcitonin (PCT) levels and made a comparison with other traditional markers such as C-reactive protein (CRP), serum amyloid (SAA) and homocysteine, considered related to vascular damage. We investigated 51 HD patients, without signs of infection, in basal conditions (during standard bicarbonate dialysis and unselected filters: X) and after 4 months of possibly more biocompatible treatments (on-line hemofiltration (HF) or HD with ultra-pure dialysate and biocompatible membranes: Y). Serum PCT (measured by immunoluminometric assay), CRP and SAA (nephelometric assay) and plasma homocysteine (measured by high performance liquid chromatography) concentrations were assessed at the beginning of dialysis (T0) and after 4 hr (T4). Patients on unselected dialysis displayed mean PCT values significantly increased after 4 hr of dialysis in comparison to those at the start of the sessions (XT4 1.56 +/- 3.93 vs. XT0 0.4 +/- 0.34 ng/mL; p < 0.05). The PCT levels detected after 4 hr of biocompatible treatments were significantly lower than those detected after 4 hr of unselected treatments (YT4 0.78 +/- 0.34 ng/mL; p < 0.05), even though the percentage of patients with positive PCT values (> 0.5 ng/mL) remained almost unchanged. No significant modification in mean levels or in the frequency of positive values was observed for CRP, SAA and homocysteine. After 4 months of highly biocompatible treatments, a reduction in intradialytic enhancements of all inflammation markers was detected. Our data support the conclusion that PCT is a more precise marker than other traditional tests to evaluate micro-inflammation and biocompatibility in HD.

Study of spin-dependent transitions and spin coherence at the (111) oriented phosphorous doped crystalline silicon to silicon dioxide interface using pulsed electrically detected magnetic resonance

NASA Astrophysics Data System (ADS)

Paik, Seoyoung

A study of spin-dependent electronic transitions at the (111) oriented phosphorous doped crystalline silicon (c-Si) to silicon dioxide (SiO 2) interface is presented for [31P] = 1015 cm-3 and [31P] = 1016 cm -3 and a temperature range between T ≈ 5K and T ≈ 15K. Using pulsed electrically detected magnetic resonance (pEDMR), spin-dependent transitions involving 31P donor states and two different interface states are observed, namely (i) Pb centers which can be identified by their characteristic anisotropy and (ii) the E' center which is attributed to defects of the near interface SiO 2 bulk. Correlation measurements of the dynamics of spin-dependent recombination confirm that previously proposed transitions between 31P and the interface defects take place. The influence of these near interface transitions on the 31P donor spin coherence time T 2 as well as the donor spin-lattice relaxation time T 1 is then investigated by comparison of spin Hahn echo decay measurements obtained from conventional bulk sensitive pulsed electron paramagnetic resonance and surface sensitive pEDMR measurements, as well as surface sensitive electrically detected inversion recovery experiments. The measurements reveal that the T2 times of both interface states and 31P donor electrons spins in proximity of them are consistently shorter than the T1 times, and both T2 and T1 times of the near interface donors are reduced by several orders of magnitude from those in the bulk, at T ≤ 13 K. The T 2 times of the 31P donor electrons are in agreement with the prediction by De Sousa that they are limited by interface defect-induced field noise. To further investigate the dynamic properties of spin-dependent near interface processes, electrical detection of spin beat oscillation between resonantly induced spin-Rabi nutation is conducted at the phosphorous doped (1016cm-3) Si(111)/SiO2 interface. Predictions of Rabi beat oscillations based on several different spin-pair models are compared with measured Rabi beat nutation data. Due to the g-factor anisotropy of the Pb center (a silicon surface dangling bond), one can tune intra-pair Larmor frequency differences (Larmor separations) by orientation of the crystal with regard to an external magnetic field. Since Larmor separation governs the number of beating spin-pairs, crystal orientation can control the beat current. This is used to identify spin states that are paired by mutual electronic transitions. Based on the agreement between hypothesis and data, the experiments confirm the presence of the previously observed 31P-P b transition and the previously hypothesized P b to near interface SiO2 bulk state (E' center) transition.

Construction of poly(lactic-co-glycolic acid)/ZnO nanorods/Ag nanoparticles hybrid coating on Ti implants for enhanced antibacterial activity and biocompatibility.

PubMed

Xiang, Yiming; Li, Jun; Liu, Xiangmei; Cui, Zhenduo; Yang, Xianjin; Yeung, K W K; Pan, Haobo; Wu, Shuilin

2017-10-01

Poly(lactic-co-glycolic acid)/Ag/ZnO nanorods coating were successfully prepared on the surface of Ti metallic implants using a hydrothermal method and subsequent spin-coating of mixtures of poly(lactic-co-glycolic acid) and silver nanoparticles. The poly(lactic-co-glycolic acid)/Ag/ZnO nanorods coating exhibited excellent antibacterial efficacy of over 96% against both Staphylococcus aureus and Escherichia coli when the initial content of Ag nanoparticles was over 3wt%. In addition, the release of both silver and zinc could last for over a hundred days due to the enwrapping of poly(lactic-co-glycolic acid). Proliferation of mouse calvarial cells exhibited minimal cytotoxicity on the poly(lactic-co-glycolic acid)/Ag/ZnO coating with an initial content of Ag nanoparticles of 1wt% and 3wt%, while it inhibited cell proliferation once this value was increased to 6wt%. The results revealed that this poly(lactic-co-glycolic acid)/Ag/ZnO composite could provide a long-lasting antibacterial approach and good cytocompatibility, thus exhibiting considerable potential for biomedical application in orthopedic and dental implants with excellent self-antibacterial activity and good biocompatibility. Copyright © 2017 Elsevier B.V. All rights reserved.

Implementing a search for gravitational waves from binary black holes with nonprecessing spin

NASA Astrophysics Data System (ADS)

Capano, Collin; Harry, Ian; Privitera, Stephen; Buonanno, Alessandra

2016-06-01

Searching for gravitational waves (GWs) from binary black holes (BBHs) with LIGO and Virgo involves matched-filtering data against a set of representative signal waveforms—a template bank—chosen to cover the full signal space of interest with as few template waveforms as possible. Although the component black holes may have significant angular momenta (spin), previous searches for BBHs have filtered LIGO and Virgo data using only waveforms where both component spins are zero. This leads to a loss of signal-to-noise ratio for signals where this is not the case. Combining the best available template placement techniques and waveform models, we construct a template bank of GW signals from BBHs with component spins χ1 ,2∈[-0.99 ,0.99 ] aligned with the orbital angular momentum, component masses m1 ,2∈[2 ,48 ]M⊙ , and total mass Mtotal≤50 M⊙ . Using effective-one-body waveforms with spin effects, we show that less than 3% of the maximum signal-to-noise ratio (SNR) of these signals is lost due to the discreetness of the bank, using the early Advanced LIGO noise curve. We use simulated Advanced LIGO noise to compare the sensitivity of this bank to a nonspinning bank covering the same parameter space. In doing so, we consider the competing effects between improved SNR and signal-based vetoes and the increase in the rate of false alarms of the aligned-spin bank due to covering a larger parameter space. We find that the aligned-spin bank can be a factor of 1.3-5 more sensitive than a nonspinning bank to BBHs with dimensionless spins >+0.6 and component masses ≳20 M⊙ . Even larger gains are obtained for systems with equally high spins but smaller component masses.

Non-exponential decoherence of radio-frequency resonance rotation of spin in storage rings

NASA Astrophysics Data System (ADS)

Saleev, A.; Nikolaev, N. N.; Rathmann, F.; Hinder, F.; Pretz, J.; Rosenthal, M.

2017-08-01

Precision experiments, such as the search for electric dipole moments of charged particles using radio-frequency spin rotators in storage rings, demand for maintaining the exact spin resonance condition for several thousand seconds. Synchrotron oscillations in the stored beam modulate the spin tune of off-central particles, moving it off the perfect resonance condition set for central particles on the reference orbit. Here, we report an analytic description of how synchrotron oscillations lead to non-exponential decoherence of the radio-frequency resonance driven up-down spin rotations. This non-exponential decoherence is shown to be accompanied by a nontrivial walk of the spin phase. We also comment on sensitivity of the decoherence rate to the harmonics of the radio-frequency spin rotator and a possibility to check predictions of decoherence-free magic energies.

Psychometric Properties of the Mini-Social Phobia Inventory

PubMed Central

Seeley-Wait, Elizabeth; Rapee, Ronald M.

2009-01-01

Objective: Although a potentially useful measure, to date, there has been only one published test of the psychometric properties of the Mini-Social Phobia Inventory (Mini-SPIN). Therefore, the psychometric properties of the Mini-SPIN, a brief 3-item screen for social anxiety disorder, were examined. Method: Participants were 186 patients diagnosed with social anxiety disorder (DSM-IV criteria) attending a specialized anxiety disorders clinic for treatment, and 56 nonclinical participants were recruited to serve as comparisons. Participants were diagnosed using the Anxiety Disorders Interview Schedule for DSM-IV, and they also completed the Mini-SPIN, the Social Interaction Anxiety Scale (SIAS), and the Social Phobia Scale (SPS). Construct validity for the Mini-SPIN was assessed by its correlations with the SIAS and the SPS. Reliability, internal consistency, discriminant validity, and sensitivity to change were also examined, and receiver operating characteristic curve analysis was conducted to determine guidelines regarding cutoff scores for the Mini-SPIN. The study was conducted between April 1999 and December 2001. Results: Supporting findings from a previous study, strong support was found for the Mini-SPIN's ability to discriminate individuals with social anxiety disorder from those without the disorder. Receiver operating characteristic analysis revealed that using a cutoff score of 6 or greater (P < .001), the Mini-SPIN demonstrates excellent sensitivity, specificity, and positive and negative predictive values. Conclusions: Findings suggest that the Mini-SPIN is a reliable and valid instrument for screening social anxiety disorder in adults. Importantly, the use of the Mini-SPIN in primary care may be one way to address the underrecognition of social anxiety disorder in such settings. Due to the ease and brevity of the measure, it also shows potential for use in epidemiology. Given that this study has revealed the ability of the Mini-SPIN to reflect treatment change, the Mini-SPIN may also be considered for use in treatment outcome studies that specifically require minimal assessment. PMID:19956461

Microfabricated spin exchange relaxation free atomic magnetometer

NASA Astrophysics Data System (ADS)

Griffith, W. Clark; Jimenez-Martinez, Ricardo; Preusser, Jan; Knappe, Svenja; Kitching, John

2009-05-01

Methods first developed at NIST for MEMS-based atomic clocks have been applied to magnetic field sensors. The sensors are built around microfabricated alkali-atom vapor cells integrated with micro-optics and a VCSEL light source. Exceptional magnetic field sensitivities can be achieved in a small volume vapor cell, especially when operated in the spin-exchange relaxation free (SERF) regime. In this technique, magnetic resonance broadening due to spin-exchange collisions is suppressed under conditions of high alkali density and low magnetic fields. We have demonstrated sensitivities better than 100 fT/Hz^1/2 with a millimeter scale SERF sensor.ootnotetextV. Shah, S. Knappe, P.D.D. Schwindt, and J. Kitching, Nature Photonics, 1, 649 (2007). Adding flux concentratorsootnotetextW.C. Griffith, R. Jimenez-Martinez, V. Shah, S. Knappe, and J. Kitching, Appl. Phys. Lett., 94, 023502 (2009). around the vapor cell further improves the sensitivity to 10 fT/Hz^1/2, potentially providing a low power, noncryogenic alternative to SQUID sensors.

Double-pinned magnetic tunnel junction sensors with spin-valve-like sensing layers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yuan, Z. H.; Huang, L.; Feng, J. F., E-mail: jiafengfeng@iphy.ac.cn

2015-08-07

MgO magnetic tunnel junction (MTJ) sensors with spin-valve-like sensing layers of Ir{sub 22}Mn{sub 78} (6)/Ni{sub 80}Fe{sub 20} (t{sub NiFe} = 20–70)/Ru (0.9)/Co{sub 40}Fe{sub 40}B{sub 20} (3) (unit: nm) have been fabricated. A linear field dependence of magnetoresistance for these MTJ sensors was obtained by carrying out a two-step field annealing process. The sensitivity and linear field range can be tuned by varying the thickness of NiFe layer and annealing temperature, and a high sensitivity of 37%/mT has been achieved in the MTJ sensors with 70 nm NiFe at the optimum annealing temperature of 230 °C. Combining the spin-valve-like sensing structure and a soft magneticmore » NiFe layer, MTJ sensors with relatively wide field sensing range have been achieved and could be promising for showing high sensitivity magnetic field sensing applications.« less

High resolution x-ray fluorescence spectroscopy - a new technique for site- and spin-selectivity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Xin

1996-12-01

X-ray spectroscopy has long been used to elucidate electronic and structural information of molecules. One of the weaknesses of x-ray absorption is its sensitivity to all of the atoms of a particular element in a sample. Through out this thesis, a new technique for enhancing the site- and spin-selectivity of the x-ray absorption has been developed. By high resolution fluorescence detection, the chemical sensitivity of K emission spectra can be used to identify oxidation and spin states; it can also be used to facilitate site-selective X-ray Absorption Near Edge Structure (XANES) and site-selective Extended X-ray Absorption Fine Structure (EXAFS). Themore » spin polarization in K fluorescence could be used to generate spin selective XANES or spin-polarized EXAFS, which provides a new measure of the spin density, or the nature of magnetic neighboring atoms. Finally, dramatic line-sharpening effects by the combination of absorption and emission processes allow observation of structure that is normally unobservable. All these unique characters can enormously simplify a complex x-ray spectrum. Applications of this novel technique have generated information from various transition-metal model compounds to metalloproteins. The absorption and emission spectra by high resolution fluorescence detection are interdependent. The ligand field multiplet model has been used for the analysis of K{alpha} and K{beta} emission spectra. First demonstration on different chemical states of Fe compounds has shown the applicability of site selectivity and spin polarization. Different interatomic distances of the same element in different chemical forms have been detected using site-selective EXAFS.« less

SNR-optimized phase-sensitive dual-acquisition turbo spin echo imaging: a fast alternative to FLAIR.

PubMed

Lee, Hyunyeol; Park, Jaeseok

2013-07-01

Phase-sensitive dual-acquisition single-slab three-dimensional turbo spin echo imaging was recently introduced, producing high-resolution isotropic cerebrospinal fluid attenuated brain images without long inversion recovery preparation. Despite the advantages, the weighted-averaging-based technique suffers from noise amplification resulting from different levels of cerebrospinal fluid signal modulations over the two acquisitions. The purpose of this work is to develop a signal-to-noise ratio-optimized version of the phase-sensitive dual-acquisition single-slab three-dimensional turbo spin echo. Variable refocusing flip angles in the first acquisition are calculated using a three-step prescribed signal evolution while those in the second acquisition are calculated using a two-step pseudo-steady state signal transition with a high flip-angle pseudo-steady state at a later portion of the echo train, balancing the levels of cerebrospinal fluid signals in both the acquisitions. Low spatial frequency signals are sampled during the high flip-angle pseudo-steady state to further suppress noise. Numerical simulations of the Bloch equations were performed to evaluate signal evolutions of brain tissues along the echo train and optimize imaging parameters. In vivo studies demonstrate that compared with conventional phase-sensitive dual-acquisition single-slab three-dimensional turbo spin echo, the proposed optimization yields 74% increase in apparent signal-to-noise ratio for gray matter and 32% decrease in imaging time. The proposed method can be a potential alternative to conventional fluid-attenuated imaging. Copyright © 2012 Wiley Periodicals, Inc.

Polydimethylsiloxane films doped with NdFeB powder: magnetic characterization and potential applications in biomedical engineering and microrobotics.

PubMed

Iacovacci, V; Lucarini, G; Innocenti, C; Comisso, N; Dario, P; Ricotti, L; Menciassi, A

2015-12-01

This work reports the fabrication, magnetic characterization and controlled navigation of film-shaped microrobots consisting of a polydimethylsiloxane-NdFeB powder composite material. The fabrication process relies on spin-coating deposition, powder orientation and permanent magnetization. Films with different powder concentrations (10 %, 30 %, 50 % and 70 % w/w) were fabricated and characterized in terms of magnetic properties and magnetic navigation performances (by exploiting an electromagnet-based platform). Standardized data are provided, thus enabling the exploitation of these composite materials in a wide range of applications, from MEMS/microrobot development to biomedical systems. Finally, the possibility to microfabricate free-standing polymeric structures and the biocompatibility of the proposed composite materials is demonstrated.

Finite Element Modeling of the Deformation of a Thin Magnetoelastic Film Compared to a Membrane Model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barham, M; White, D; Steigmann, D

2009-04-08

Recently a new class of biocompatible elastic polymers loaded with small ferrous particles (magnetoelastomer) was developed at Lawrence Livermore National Laboratory. This new material was formed as a thin film using spin casting. The deformation of this material using a magnetic field has many possible applications to microfluidics. Two methods will be used to calculate the deformation of a circular magneto-elastomeric film subjected to a magnetic field. The first method is an arbitrary Lagrangian-Eulerian (ALE) finite element method (FEM) and the second is based on nonlinear continuum electromagnetism and continuum elasticity in the membrane limit. The comparison of these twomore » methods is used to test/validate the finite element method.« less

A Method of Flight Measurement of Spins

NASA Technical Reports Server (NTRS)

Soule, Hartley A; Scudder, Nathan F

1932-01-01

A method is described involving the use of recording turn meters and accelerometers and a sensitive altimeter, by means of which all of the physical quantities necessary for the complete determination of the flight path, motion, attitude, forces, and couples of a fully developed spin can be obtained in flight. Data are given for several spins of two training type airplanes which indicate that the accuracy of the results obtained with the method is satisfactory.

Neutron Resonance Spin Determination Using Multi-Segmented Detector DANCE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baramsai, B.; Mitchell, G. E.; Chyzh, A.

2011-06-01

A sensitive method to determine the spin of neutron resonances is introduced based on the statistical pattern recognition technique. The new method was used to assign the spins of s-wave resonances in {sup 155}Gd. The experimental neutron capture data for these nuclei were measured with the DANCE (Detector for Advanced Neutron Capture Experiment) calorimeter at the Los Alamos Neutron Science Center. The highly segmented calorimeter provided detailed multiplicity distributions of the capture {gamma}-rays. Using this information, the spins of the neutron capture resonances were determined. With these new spin assignments, level spacings are determined separately for s-wave resonances with J{supmore » {pi}} = 1{sup -} and 2{sup -}.« less

Improving liquid chromatography-mass spectrometry sensitivity using a subambient pressure ionization with nanoelectrospray (SPIN) interface

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tang, Keqi; Page, Jason S.; Marginean, Ioan

2011-04-22

In this work the Subambient Pressure Ionization with Nanoelectrospray (SPIN) ion source and interface which operates at ~15-30 Torr is demonstrated to be compatible with gradient reversed-phase liquid chromatography-MS applications, exemplified here with the analysis of complex samples (a protein tryptic digest and a whole cell lysate). A low liquid chromatographic flow rate (100-400 nL/min) allowed stable electrospray to be established while avoiding electrical breakdown. Efforts to increase the operating pressure of the SPIN source relative to previously reported designs prevented solvent freezing and enhanced charged cluster/droplet desolvation. A 5-12-fold improvement in sensitivity relative to a conventional atmospheric pressure nanoelectrospraymore » ionization (ESI) source was obtained for detected peptides.« less

Magnetic field-modulated photo-thermo-electric effect in Fe/GaAs film

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qiao, Shuang; Liu, Jihong; Yan, Guoying

2015-11-02

Ferromagnet/semiconductor heterostructure, such as Fe/GaAs, is always one of the key issues in spintronics due to its prerequisite for the realization of spin sensitive devices. In this letter, a lateral photoelectric effect (LPE) was observed in Fe/GaAs. Our results show that the sensitivity was not related to laser wavelength, but only proportional to laser power, suggesting that the lateral photovoltage was induced by photo-thermo-electric effect. Moreover, we also observe that the voltage signal increases with the increase in applied field due to decreasing scattering probability for spin-polarized electrons. Our finding of LPE adds another functionality to the Fe/GaAs system andmore » will be useful in development of spin-polarized voltage devices.« less

A Paramagnetic Molecular Voltmeter

PubMed Central

Surek, Jack T.; Thomas, David D.

2008-01-01

We have developed a general electron paramagnetic resonance (EPR) method to measure electrostatic potential at spin labels on proteins to millivolt accuracy. Electrostatic potential is fundamental to energy-transducing proteins like myosin, because molecular energy storage and retrieval is primarily electrostatic. Quantitative analysis of protein electrostatics demands a site-specific spectroscopic method sensitive to millivolt changes. Previous electrostatic potential studies on macromolecules fell short in sensitivity, accuracy and/or specificity. Our approach uses fast-relaxing charged and neutral paramagnetic relaxation agents (PRAs) to increase nitroxide spin label relaxation rate solely through collisional spin exchange. These PRAs were calibrated in experiments on small nitroxides of known structure and charge to account for differences in their relaxation efficiency. Nitroxide longitudinal (R1) and transverse (R2) relaxation rates were separated by applying lineshape analysis to progressive saturation spectra. The ratio of measured R1 increases for each pair of charged and neutral PRAs measures the shift in local PRA concentration due to electrostatic potential. Voltage at the spin label is then calculated using the Boltzmann equation. Measured voltages for two small charged nitroxides agree with Debye-Hückel calculations. Voltage for spin-labeled myosin fragment S1 also agrees with calculation based on the pK shift of the reacted cysteine. PMID:17964835

Effects of superparamagnetic iron oxide nanoparticles on the longitudinal and transverse relaxation of hyperpolarized xenon gas

NASA Astrophysics Data System (ADS)

Burant, Alex; Antonacci, Michael; McCallister, Drew; Zhang, Le; Branca, Rosa Tamara

2018-06-01

SuperParamagnetic Iron Oxide Nanoparticles (SPIONs) are often used in magnetic resonance imaging experiments to enhance Magnetic Resonance (MR) sensitivity and specificity. While the effect of SPIONs on the longitudinal and transverse relaxation time of 1H spins has been well characterized, their effect on highly diffusive spins, like those of hyperpolarized gases, has not. For spins diffusing in linear magnetic field gradients, the behavior of the magnetization is characterized by the relative size of three length scales: the diffusion length, the structural length, and the dephasing length. However, for spins diffusing in non-linear gradients, such as those generated by iron oxide nanoparticles, that is no longer the case, particularly if the diffusing spins experience the non-linearity of the gradient. To this end, 3D Monte Carlo simulations are used to simulate the signal decay and the resulting image contrast of hyperpolarized xenon gas near SPIONs. These simulations reveal that signal loss near SPIONs is dominated by transverse relaxation, with little contribution from T1 relaxation, while simulated image contrast and experiments show that diffusion provides no appreciable sensitivity enhancement to SPIONs.

Spin reorientation of a nonsymmetric body with energy dissipation

NASA Technical Reports Server (NTRS)

Cenker, R. J.

1973-01-01

Stable rotating semi-rigid bodies were demonstrated analytically, and verified in flights such as Explorer 1 and ATS-5 satellites. The problem arises from the two potential orientations which the final spin vector can take after large angle reorientation from minor to major axis, i.e., along the positive or negative axis of the maximum inertia. Reorientation of a satellite initially spinning about the minor axis using an energy dissipation device may require that the final spin orientation be controlled. Examples of possible applications are the Apogee Motor Assembly with Paired Satellites (AMAPS) configuration, where proper orientation of the thruster is required; and reorientation of ATS-5, where the spin sensitive nature of the despin device (yo-yo mechanism) requires that the final spin vector point is a specified direction.

Using lead chalcogenide nanocrystals as spin mixers: a perspective on near-infrared-to-visible upconversion.

PubMed

Nienhaus, Lea; Wu, Mengfei; Bulović, Vladimir; Baldo, Marc A; Bawendi, Moungi G

2018-03-01

The process of upconversion leads to emission of photons higher in energy than the incident photons. Near-infrared-to-visible upconversion, in particular, shows promise in sub-bandgap sensitization of silicon and other optoelectronic materials, resulting in potential applications ranging from photovoltaics that exceed the Shockley-Queisser limit to infrared imaging. A feasible mechanism for near-infrared-to-visible upconversion is triplet-triplet annihilation (TTA) sensitized by colloidal nanocrystals (NCs). Here, the long lifetime of spin-triplet excitons in the organic materials that undergo TTA makes upconversion possible under incoherent excitation at relatively low photon fluxes. Since this process relies on optically inactive triplet states, semiconductor NCs are utilized as efficient spin mixers, absorbing the incident light and sensitizing the triplet states of the TTA material. The state-of-the-art system uses rubrene with a triplet energy of 1.14 eV as the TTA medium, and thus allows upconversion of light with photon energies above ∼1.1 eV. In this perspective, we review the field of lead sulfide (PbS) NC-sensitized near-infrared-to-visible upconversion, discuss solution-based upconversion, and highlight progress made on solid-state upconversion devices.

Confirming Pseudomonas putida as a reliable bioassay for demonstrating biocompatibility enhancement by solar photo-oxidative processes of a biorecalcitrant effluent.

PubMed

García-Ripoll, A; Amat, A M; Arques, A; Vicente, R; Ballesteros Martín, M M; Pérez, J A Sánchez; Oller, I; Malato, S

2009-03-15

Experiments based on Vibrio fischeri, activated sludge and Pseudomonas putida have been employed to check variation in the biocompatibility of an aqueous solution of a commercial pesticide, along solar photo-oxidative process (TiO(2) and Fenton reagent). Activated sludge-based experiments have demonstrated a complete detoxification of the solution, although important toxicity is still detected according to the more sensitive V. fischeri assays. In parallel, the biodegradability of organic matter is strongly enhanced, with BOD(5)/COD ratio above 0.8. Bioassays run with P. putida have given similar trends, remarking the convenience of using P. putida culture as a reliable and reproducible method for assessing both toxicity and biodegradability, as a substitute to other more time consuming methods.

Achievement of high diode sensitivity via spin torque-induced resonant expulsion in vortex magnetic tunnel junction

NASA Astrophysics Data System (ADS)

Tsunegi, Sumito; Taniguchi, Tomohiro; Yakushiji, Kay; Fukushima, Akio; Yuasa, Shinji; Kubota, Hitoshi

2018-05-01

We investigated the spin-torque diode effect in a magnetic tunnel junction with FeB free layer. Vortex-core expulsion was observed near the boundary between vortex and uniform states. A high diode voltage of 24 mV was obtained with alternative input power of 0.3 µW, corresponding to huge diode sensitivity of 80,000 mV/mW. In the expulsion region, a broad peak in the high frequency region was observed, which is attributed to the weak excitation of uniform magnetization by thermal noise. The high diode sensitivity is of great importance for device applications such as telecommunications, radar detectors, and high-speed magnetic-field sensors.

Repetitive readout of a single electronic spin via quantum logic with nuclear spin ancillae.

PubMed

Jiang, L; Hodges, J S; Maze, J R; Maurer, P; Taylor, J M; Cory, D G; Hemmer, P R; Walsworth, R L; Yacoby, A; Zibrov, A S; Lukin, M D

2009-10-09

Robust measurement of single quantum bits plays a key role in the realization of quantum computation and communication as well as in quantum metrology and sensing. We have implemented a method for the improved readout of single electronic spin qubits in solid-state systems. The method makes use of quantum logic operations on a system consisting of a single electronic spin and several proximal nuclear spin ancillae in order to repetitively readout the state of the electronic spin. Using coherent manipulation of a single nitrogen vacancy center in room-temperature diamond, full quantum control of an electronic-nuclear system consisting of up to three spins was achieved. We took advantage of a single nuclear-spin memory in order to obtain a 10-fold enhancement in the signal amplitude of the electronic spin readout. We also present a two-level, concatenated procedure to improve the readout by use of a pair of nuclear spin ancillae, an important step toward the realization of robust quantum information processors using electronic- and nuclear-spin qubits. Our technique can be used to improve the sensitivity and speed of spin-based nanoscale diamond magnetometers.

Control of Low-Field Hysteresis Loop Shift of Spin Valves

NASA Astrophysics Data System (ADS)

Chernyshova, T. A.; Milyaev, M. A.; Naumova, L. I.; Proglyado, V. V.; Maksimova, I. K.; Pavlova, A. Yu.; Blagodatkov, D. V.; Ustinov, V. V.

2017-12-01

Spin valves that comprise synthetic antiferromagnet as a component of pinned layer and an exchange-coupled ferromagnet/Ru/ferromagnet structure in the free layer have been prepared by magnetron sputtering. Microobjects have been formed from spin valves by optical and electron-beam lithography. It has been shown that the shift of the low-field magnetoresistance hysteresis loop decreases as the thicknes of the Ru spacer in the free layer of spin valve increases. The almost hysteresis-free odd-field dependences of the magnetoresistance were obtained for micron-sized samples; in this case, the sensitivity is 0.2%/Oe.

Improvement in T2* via Cancellation of Spin Bath Induced Dephasing in Solid-State Spins

NASA Astrophysics Data System (ADS)

Bauch, Erik; Hart, Connor; Schloss, Jennifer; Turner, Matthew; Barry, John; Walsworth, Ronald L.

2017-04-01

In measurements using ensembles of nitrogen vacancy (NV) centers in diamond, the magnetic field sensitivity can be improved by increasing the NV spin dephasing time, T2*. For NV ensembles, T2* is limited by dephasing arising from variations in the local environment sensed by individual NVs, such as applied magnetic fields, noise induced by other nearby spins, and strain. Here, we describe a systematic study of parameters influencing the NV ensemble T2*, and efforts to mitigate sources of inhomogeneity with demonstrated T2* improvements exceeding one order of magnitude.

Fast Single-Shot Hold Spin Readout in Double Quantum Dots

NASA Astrophysics Data System (ADS)

Bogan, Alexander; Studenikin, Sergei; Korkusinski, Marek; Aers, Geof; Gaudreau, Louis; Zawadzki, Piotr; Sachrajda, Andy; Tracy, Lisa; Reno, John; Hargett, Terry

Solid state spin qubits in quantum dots hold promise as scalable, high-density qubits in quantum information processing architectures. While much of the experimental investigation of these devices and their physics has focused on confined electron spins, hole spins in III-V semiconductors are attractive alternatives to electrons due to the reduced hyperfine coupling between the spin and the incoherent nuclear environment. In this talk, we will discuss a measurement protocol of the hole spin relaxation time T1 in a gated lateral GaAs double quantum dot tuned to the one and two-hole regimes, as well as a new technique for single-shot projective measurement of a single spin in tens of nanoseconds or less. The technique makes use of fast non-spin-conserving inter-dot transitions permitted by strong spin-orbit interactions for holes, as well as the latching of the charge state of the second quantum dot for enhanced sensitivity. This technique allows a direct measurement of the single spin relaxation time on time-scales set by physical device rather than by limitations of the measurement circuit.

Magnon and phonon thermometry with inelastic light scattering

NASA Astrophysics Data System (ADS)

Olsson, Kevin S.; An, Kyongmo; Li, Xiaoqin

2018-04-01

Spin caloritronics investigates the interplay between the transport of spin and heat. In the spin Seebeck effect, a thermal gradient across a magnetic material generates a spin current. A temperature difference between the energy carriers of the spin and lattice subsystems, namely the magnons and phonons, is necessary for such thermal nonequilibrium generation of spin current. Inelastic light scattering is a powerful method that can resolve the individual temperatures of magnons and phonons. In this review, we discuss the thermometry capabilities of inelastic light scattering for measuring optical and acoustic phonons, as well as magnons. A scattering spectrum offers three temperature sensitive parameters: frequency shift, linewidth, and integrated intensity. We discuss the temperatures measured via each of these parameters for both phonon and magnons. Finally, we discuss inelastic light scattering experiments that have examined the magnon and phonon temperatures in thermal nonequilibrium which are particularly relevant to spin caloritronic phenomena.

Spin texture of the surface state of three-dimensional Dirac material Ca3PbO

NASA Astrophysics Data System (ADS)

Kariyado, Toshikaze

2015-04-01

The bulk and surface electronic structures of a candidate three-dimensional Dirac material Ca3PbO and its family are discussed especially focusing on the spin texture on the surface states. We first explain the basic features of the bulk band structure of Ca3PbO, such as emergence of Dirac fermions near the Fermi energy, and compare it with the other known three-dimensional Dirac semimetals. Then, the surface bands and spin-texture on them are investigated in detail. It is shown that the surface bands exhibit strong momentum-spin locking, which may be useful in some application for spin manipulation, induced by a combination of the inversion symmetry breaking at the surface and the strong spin-orbit coupling of Pb atoms. The surface band structure and the spin-textures are sensitive to the surface types.

Investigation of iron spin crossover pressure in Fe-bearing MgO using hybrid functional

NASA Astrophysics Data System (ADS)

Cheng, Ya; Wang, Xianlong; Zhang, Jie; Yang, Kaishuai; Zhang, Chuanguo; Zeng, Zhi; Lin, Haiqin

2018-04-01

Pressure-induced spin crossover behaviors of Fe-bearing MgO were widely investigated by using an LDA  +  U functional for describing the strongly correlated Fe–O bonding. Moreover, the simulated spin crossover pressures depend on the applied U values, which are sensitive to environments and parameters. In this work, the spin crossover pressures of (Mg1‑x ,Fe x )O are investigated by using the hybrid functional with a uniform parameter. Our results indicate that the spin crossover pressures increase with increasing iron concentration. For example, the spin crossover pressure of (Mg0.03125,Fe0.96875)O and FeO was 56 GPa and 127 GPa, respectively. The calculated crossover pressures agreed well with the experimental observations. Therefore, the hybrid functional should be an effective method for describing the pressure-induced spin crossover behaviors in transition metal oxides.

Nanocellulose-based biosensors: design, preparation, and activity of peptide-linked cotton cellulose nanocrystals having fluorimetric and colorimetric elastase detection sensitivity

USDA-ARS?s Scientific Manuscript database

Nanocrystalline cellulose is an amphiphilic, high surface area material that can be easily functionalized and is biocom-patible and eco-friendly. It has been used singularly and in combination with other nanomaterials to optimize biosensor design. The attachment of peptides and proteins to nanocryst...

Dual-spin attitude control for outer planet missions

NASA Technical Reports Server (NTRS)

Ward, R. S.; Tauke, G. J.

1977-01-01

The applicability of dual-spin technology to a Jupiter orbiter with probe mission was investigated. Basic mission and system level attitude control requirements were established and preliminary mechanization and control concepts developed. A comprehensive 18-degree-of-freedom digital simulation was utilized extensively to establish control laws, study dynamic interactions, and determined key sensitivities. Fundamental system/subsystem constraints were identified, and the applicability of dual-spin technology to a Jupiter orbiter with probe mission was validated.

Measurement of axial spin observables in the polarized deuteron-polarized proton breakup at 270MeV

NASA Astrophysics Data System (ADS)

Whitaker, Thomas Jenkins

We report the measurement of "axial" spin observables in the dp breakup reaction at 270MeV. These measurements were made using a stored polarized "cooled" deuteron beam and a polarized internal hydrogen target at the Indiana University Cyclotron Facility (IUCF). Given our beam and target spin-alignment directions we were able to measure the axial spin observables Apz , Cy,x - Cx,y, and Czz,z. Axial spin observables are the subset of observables which are antisymmetric under the parity operation and are thus forbidden in reactions where the outgoing momenta are coplanar with the beam momentum. It has been argued that axial observables may be more sensitive to a three-body force than other spin observables. We compare our measurements to theoretical predictions based on the CD-Bonn nucleon-nucleon potential and the TM ' three-nucleon force, using a new method to correctly take into account the experimental constraints. The only previous measurement of Apz for pd breakup was carried out at 9MeV and yielded a result consistent with zero. In contrast, at Tp = 135 MeV, the present experiment reports a sizeable value for Apz , Cy,x - Cx,y, and Czz,z. To our knowledge, this is the first time axial correlation coefficients have been measured in a nuclear reaction. The expected sensitivity of axial observables to the three-nucleon force is not confirmed by our measurement.

Transient NOE enhancement in solid-state MAS NMR of mobile systems

NASA Astrophysics Data System (ADS)

Cui, Jiangyu; Li, Jun; Peng, Xinhua; Fu, Riqiang

2017-11-01

It has been known that the heteronuclear cross-relaxation affects the dilute S spin magnetization along the longitudinal direction, causing an overshoot phenomenon for those mobile systems in spin-lattice relaxation rate measurements. Here, we analyze the Solomon equations for an I-S system and derive the transient cross relaxation effect as to when an overshoot phenomenon would take place and what the maximum enhancement could be at the time of the overshoot. In order to utilize such a transient nuclear Overhauser effect (NOE), we first time apply it to dynamic solid samples by inverting the 1H magnetization prior to the excitation of the S spin. It is found that the overshoot depends on the ratio of the I and S spin-lattice relaxation rates, i.e. RSS /RII . When RSS /RII ≫ 1 , the maximum enhancement factor for transient NOE could be larger than that obtained in steady-state NOE experiments. Furthermore, transient NOE appears to be more efficient in terms of sensitivity enhancement of dilute spins in solid-state NMR of mobile systems than the traditional cross polarization scheme whose efficiency is greatly compromised by molecular mobility. A sample of natural abundance L-isoleucine amino acid, in which the spin-lattice relaxation rates for the four methyl carbons are different, has been used to demonstrate sensitivity enhancement factors under various experimental schemes.

Nonlocally sensing the magnetic states of nanoscale antiferromagnets with an atomic spin sensor

PubMed Central

Yan, Shichao; Malavolti, Luigi; Burgess, Jacob A. J.; Droghetti, Andrea; Rubio, Angel; Loth, Sebastian

2017-01-01

The ability to sense the magnetic state of individual magnetic nano-objects is a key capability for powerful applications ranging from readout of ultradense magnetic memory to the measurement of spins in complex structures with nanometer precision. Magnetic nano-objects require extremely sensitive sensors and detection methods. We create an atomic spin sensor consisting of three Fe atoms and show that it can detect nanoscale antiferromagnets through minute, surface-mediated magnetic interaction. Coupling, even to an object with no net spin and having vanishing dipolar stray field, modifies the transition matrix element between two spin states of the Fe atom–based spin sensor that changes the sensor’s spin relaxation time. The sensor can detect nanoscale antiferromagnets at up to a 3-nm distance and achieves an energy resolution of 10 μeV, surpassing the thermal limit of conventional scanning probe spectroscopy. This scheme permits simultaneous sensing of multiple antiferromagnets with a single-spin sensor integrated onto the surface. PMID:28560346

Spin-orbit beams for optical chirality measurement

NASA Astrophysics Data System (ADS)

Samlan, C. T.; Suna, Rashmi Ranjan; Naik, Dinesh N.; Viswanathan, Nirmal K.

2018-01-01

Accurate measurement of chirality is essential for the advancement of natural and pharmaceutical sciences. We report here a method to measure chirality using non-separable states of light with geometric phase-gradient in the circular polarization basis, which we refer to as spin-orbit beams. A modified polarization Sagnac interferometer is used to generate spin-orbit beams wherein the spin and orbital angular momentum of the input Gaussian beam are coupled. The out-of-phase interference between counter-propagating Gaussian beams with orthogonal spin states and lateral-shear or/and linear-phase difference between them results in spin-orbit beams with linear and azimuthal phase gradient. The spin-orbit beams interact efficiently with the chiral medium, inducing a measurable change in the center-of-mass of the beam, using the polarization rotation angle and hence the chirality of the medium are accurately calculated. Tunable dynamic range of measurement and flexibility to introduce large values of orbital angular momentum for the spin-orbit beam, to improve the measurement sensitivity, highlight the techniques' versatility.

DEER Sensitivity between Iron Centers and Nitroxides in Heme-Containing Proteins Improves Dramatically Using Broadband, High-Field EPR

PubMed Central

2016-01-01

This work demonstrates the feasibility of making sensitive nanometer distance measurements between Fe(III) heme centers and nitroxide spin labels in proteins using the double electron–electron resonance (DEER) pulsed EPR technique at 94 GHz. Techniques to measure accurately long distances in many classes of heme proteins using DEER are currently strongly limited by sensitivity. In this paper we demonstrate sensitivity gains of more than 30 times compared with previous lower frequency (X-band) DEER measurements on both human neuroglobin and sperm whale myoglobin. This is achieved by taking advantage of recent instrumental advances, employing wideband excitation techniques based on composite pulses and exploiting more favorable relaxation properties of low-spin Fe(III) in high magnetic fields. This gain in sensitivity potentially allows the DEER technique to be routinely used as a sensitive probe of structure and conformation in the large number of heme and many other metalloproteins. PMID:27035368

Femtosecond optical reflectivity measurements of lattice-mediated spin repulsions in photoexcited LaCoO3 thin films

NASA Astrophysics Data System (ADS)

Bielecki, J.; Rata, A. D.; Börjesson, L.

2014-01-01

We present results on the temperature dependence of ultrafast electron and lattice dynamics, measured with pump-probe transient reflectivity experiments, of an epitaxially grown LaCoO3 thin film under tensile strain. Probing spin-polarized transitions into the antibonding eg band provides a measure of the low-spin fraction, both as a function of temperature and time after photoexcitation. It is observed that femtosecond laser pulses destabilize the constant low-spin fraction (˜63%-64%) in equilibrium into a thermally activated state, driven by a subpicosecond change in spin gap Δ. From the time evolution of the low-spin fraction, it is possible to disentangle the thermal and lattice contributions to the spin state. A lattice mediated spin repulsion, identified as the governing factor determining the equilibrium spin state in thin-film LaCoO3, is observed. These results suggests that time-resolved spectroscopy is a sensitive probe of the spin state in LaCoO3 thin films, with the potential to bring forward quantitative insight into the complicated interplay between structure and spin state in LaCoO3.

Effects of several factors on theoretical predictions of airplane spin characteristics. [dynamic models

NASA Technical Reports Server (NTRS)

Bihrle, W., Jr.; Barnhart, B.

1974-01-01

The influence of different mathematical and aerodynamic models on computed spin motion was investigated along with the importance of some of the aerodynamic and nonaerodynamic quantities defined in these models. An analytical technique was used which included the aerodynamic forces and moments acting on a spinning aircraft due to steady rotational flow and the contribution of the rotary derivatives to the oscillatory component of the total angular rates. It was shown that (1) during experimental-analytical correlation studies, the flight-recorded control time histories must be faithfully duplicated since the spinning motion can be sensitive to a small change in the application of the spin entry controls; (2) an error in the assumed inertias, yawing moments at high angle of attack, and initial spin entry bank angle do not influence the developed spin significantly; (3) damping in pitch derivatives and the center of gravity location play a role in the spinning motion; and (4) the experimental spin investigations conducted in a constant atmospheric density environment duplicate the Froude number only at the initial full-scale spin altitude (since the full-scale airplane at high altitudes experiences large density changes during the spin.)

Label free selective detection of estriol using graphene oxide-based fluorescence sensor

NASA Astrophysics Data System (ADS)

Kushwaha, H. S.; Sao, Reshma; Vaish, Rahul

2014-07-01

Water-soluble and fluorescent Graphene oxide (GO) is biocompatible, easy, and economical to synthesize. Interestingly, GO is also capable of quenching fluorescence. On the basis of its fluorescence and quenching abilities, GO has been reported to serve as an energy acceptor in a fluorescence resonance energy transfer (FRET) sensor. GO-based FRET biosensors have been widely reported for sensing of proteins, nucleic acid, ATP (Adenosine triphosphate), etc. GO complexes with fluorescent dyes and enzymes have been used to sense metal ions. Graphene derivatives have been used for sensing endocrine-disrupting chemicals like bisphenols and chlorophenols with high sensitivity and good reproducibility. On this basis, a novel GO based fluorescent sensor has been successfully designed to detect estriol with remarkable selectivity and sensitivity. Estriol is one of the three estrogens in women and is considered to be medically important. Estriol content of maternal urine or plasma acts as an important screening marker for estimating foetal growth and development. In addition, estriol is also used as diagnostic marker for diseases like breast cancer, osteoporosis, neurodegenerative and cardiovascular diseases, insulin resistance, lupus erythematosus, endometriosis, etc. In this present study, we report for the first time a rapid, sensitive with detection limit of 1.3 nM, selective and highly biocompatible method for label free detection of estriol under physiological conditions using fluorescence assay.

Phase transitions and thermal entanglement of the distorted Ising-Heisenberg spin chain: topology of multiple-spin exchange interactions in spin ladders

NASA Astrophysics Data System (ADS)

Arian Zad, Hamid; Ananikian, Nerses

2017-11-01

We consider a symmetric spin-1/2 Ising-XXZ double sawtooth spin ladder obtained from distorting a spin chain, with the XXZ interaction between the interstitial Heisenberg dimers (which are connected to the spins based on the legs via an Ising-type interaction), the Ising coupling between nearest-neighbor spins of the legs and rungs spins, respectively, and additional cyclic four-spin exchange (ring exchange) in the square plaquette of each block. The presented analysis supplemented by results of the exact solution of the model with infinite periodic boundary implies a rich ground state phase diagram. As well as the quantum phase transitions, the characteristics of some of the thermodynamic parameters such as heat capacity, magnetization and magnetic susceptibility are investigated. We prove here that among the considered thermodynamic and thermal parameters, solely heat capacity is sensitive versus the changes of the cyclic four-spin exchange interaction. By using the heat capacity function, we obtain a singularity relation between the cyclic four-spin exchange interaction and the exchange coupling between pair spins on each rung of the spin ladder. All thermal and thermodynamic quantities under consideration should be investigated by regarding those points which satisfy the singularity relation. The thermal entanglement within the Heisenberg spin dimers is investigated by using the concurrence, which is calculated from a relevant reduced density operator in the thermodynamic limit.

Coherent manipulation of spin correlations in the Hubbard model

NASA Astrophysics Data System (ADS)

Wurz, N.; Chan, C. F.; Gall, M.; Drewes, J. H.; Cocchi, E.; Miller, L. A.; Pertot, D.; Brennecke, F.; Köhl, M.

2018-05-01

We coherently manipulate spin correlations in a two-component atomic Fermi gas loaded into an optical lattice using spatially and time-resolved Ramsey spectroscopy combined with high-resolution in situ imaging. This technique allows us not only to imprint spin patterns but also to probe the static magnetic structure factor at an arbitrary wave vector, in particular, the staggered structure factor. From a measurement along the diagonal of the first Brillouin zone of the optical lattice, we determine the magnetic correlation length and the individual spatial spin correlators. At half filling, the staggered magnetic structure factor serves as a sensitive thermometer, which we employ to study the equilibration in the spin and density sector during a slow quench of the lattice depth.

The first observation of Carbon-13 spin noise spectra

PubMed Central

Schlagnitweit, Judith; Müller, Norbert

2012-01-01

We demonstrate the first 13C NMR spin noise spectra obtained without any pulse excitation by direct detection of the randomly fluctuating noise from samples in a cryogenically cooled probe. Noise power spectra were obtained from 13C enriched methanol and glycerol samples at 176 MHz without and with 1H decoupling, which increases the sensitivity without introducing radio frequency interference with the weak spin noise. The multiplet amplitude ratios in 1H coupled spectra indicate that, although pure spin noise prevails in these spectra, the influence of absorbed circuit noise is still significant at the high concentrations used. In accordance with the theory heteronuclear Overhauser enhancements are absent from the 1H-decoupled 13C spin noise spectra. PMID:23041799

NMR study of nematic spin fluctuations in a detwinned single crystal of underdoped Ba ( Fe 1 ₋ x Co x ) 2 As 2

DOE PAGES

Kissikov, T.; Dioguardi, A. P.; Timmons, E. I.; ...

2016-10-11

Here, we report the experimental details of how mechanical detwinning can be implemented in tandem with high-sensitivity nuclear magnetic resonance measurements and use this setup to measure the in-plane anisotropy of the spin-lattice relaxation rate in underdoped Ba(Fe 1–xCo x) 2As 2 with x = 0.048. The anisotropy reaches a maximum of 30% at TN, and the recovery data reveal that the glassy behavior of the spin fluctuations present in the twinned state persist in the fully detwinned crystal. A theoretical model is presented to describe the spin-lattice relaxation rate in terms of anisotropic nematic spin fluctuations.

14 GHz longitudinally detected electron spin resonance using microHall sensors

NASA Astrophysics Data System (ADS)

Bouterfas, M.; Mouaziz, S.; Popovic, R. S.

2017-09-01

In this work we developed a home-made LOngitudinally Detected Electron Spin Resonance (LODESR) spectrometer based on a microsize Hall sensor. A coplanar waveguide (CPW)-resonator is used to induce microwave-excitation on the sample at 14 GHz. We used InSb cross-shaped Hall devices with active areas of (10 μm × 10 μm) and (5 μm × 5 μm) . Signal intensities of the longitudinal magnetization component of DPPH and YIG samples of volumes about (10 μm) 3 and (5 μm) 3 , are measured under amplitude and frequency modulated microwave magnetic field generated by the CPW-resonator. At room temperature, 109spins /G √Hz sensitivity is achieved for 0.2mT linewidth, a result which is still better than most of inductive detected LODESR sensitivities.

Single-ion quantum lock-in amplifier.

PubMed

Kotler, Shlomi; Akerman, Nitzan; Glickman, Yinnon; Keselman, Anna; Ozeri, Roee

2011-05-05

Quantum metrology uses tools from quantum information science to improve measurement signal-to-noise ratios. The challenge is to increase sensitivity while reducing susceptibility to noise, tasks that are often in conflict. Lock-in measurement is a detection scheme designed to overcome this difficulty by spectrally separating signal from noise. Here we report on the implementation of a quantum analogue to the classical lock-in amplifier. All the lock-in operations--modulation, detection and mixing--are performed through the application of non-commuting quantum operators to the electronic spin state of a single, trapped Sr(+) ion. We significantly increase its sensitivity to external fields while extending phase coherence by three orders of magnitude, to more than one second. Using this technique, we measure frequency shifts with a sensitivity of 0.42 Hz Hz(-1/2) (corresponding to a magnetic field measurement sensitivity of 15 pT Hz(-1/2)), obtaining an uncertainty of less than 10 mHz (350 fT) after 3,720 seconds of averaging. These sensitivities are limited by quantum projection noise and improve on other single-spin probe technologies by two orders of magnitude. Our reported sensitivity is sufficient for the measurement of parity non-conservation, as well as the detection of the magnetic field of a single electronic spin one micrometre from an ion detector with nanometre resolution. As a first application, we perform light shift spectroscopy of a narrow optical quadrupole transition. Finally, we emphasize that the quantum lock-in technique is generic and can potentially enhance the sensitivity of any quantum sensor. ©2011 Macmillan Publishers Limited. All rights reserved

Tannic Acid/Fe3+/Ag Nanofilm Exhibiting Superior Photodynamic and Physical Antibacterial Activity.

PubMed

Xu, Ziqiang; Wang, Xiuhua; Liu, Xiangmei; Cui, Zhenduo; Yang, Xianjin; Yeung, Kelvin Wai Kwok; Chung, Jonathan Chiyuen; Chu, Paul K; Wu, Shuilin

2017-11-15

Silver nanoparticles (AgNPs) enwrapped in the biologically safe tannic acid (TA)/Fe 3+ nanofilm are synthesized by an ultrafast, green, simple, and universal method. The physical antibacterial activity and photodynamic antibacterial therapy (PAT) efficacy of the TA/Fe 3+ /AgNPs nanofilm were investigated for the first time, which exhibited a strong physical antibacterial activity as well as great biocompatibility, through in vitro and in vivo studies. The results disclosed that this hybrid coating could possess high PAT capabilities upon irradiation under a visible light of 660 nm, which is longer than those of previously reported green and blue sensitization light, thus allowing deeper light penetration into biological tissues. Electron spin resonance (ESR) spectra proved that the PAT efficacy of the TA/Fe 3+ /AgNPs nanofilm was associated with the yields of singlet oxygen ( 1 O 2 ) under the irradiation of visible light (660 nm). A higher PAT efficiency of 100 and 94% against Escherichia coli and Staphylococcus aureus could be achieved within 20 min of illumination under 660 nm visible light, whereas the innate physical antibacterial activity of AgNPs could endow the implants with long-term prevention of bacterial infection. The mechanism of PAT may be associated with the formation of oxidative stress and oxidative damage to key biomolecules (proteins and lipids) in bacteria. Our results reveal that the synergistic action of both PAT and physical action of AgNPs in this hybrid nanofilm is an effective way to inactivate bacteria, with minimal side effects.

Distinction of nuclear spin states with the scanning tunneling microscope.

PubMed

Natterer, Fabian Donat; Patthey, François; Brune, Harald

2013-10-25

We demonstrate rotational excitation spectroscopy with the scanning tunneling microscope for physisorbed H(2) and its isotopes HD and D(2). The observed excitation energies are very close to the gas phase values and show the expected scaling with the moment of inertia. Since these energies are characteristic for the molecular nuclear spin states we are able to identify the para and ortho species of hydrogen and deuterium, respectively. We thereby demonstrate nuclear spin sensitivity with unprecedented spatial resolution.

Characteristics of TiO2/ZnO bilayer film towards pH sensitivity prepared by different spin coating deposition process

NASA Astrophysics Data System (ADS)

Rahman, Rohanieza Abdul; Zulkefle, Muhammad Al Hadi; Abdullah, Wan Fazlida Hanim; Rusop, M.; Herman, Sukreen Hana

2016-07-01

In this study, titanium dioxide (TiO2) and zinc oxide (ZnO) bilayer film for pH sensing application will be presented. TiO2/ZnO bilayer film with different speed of spin-coating process was deposited on Indium Tin Oxide (ITO), prepared by sol-gel method. This fabricated bilayer film was used as sensing membrane for Extended Gate Field-Effect Transistor (EGFET) for pH sensing application. Experimental results indicated that the sensor is able to detect the sensitivity towards pH buffer solution. In order to obtained the result, sensitivity measurement was done by using the EGFET setup equipment with constant-current (100 µA) and constant-voltage (0.3 V) biasing interfacing circuit. TiO2/ZnO bilayer film which the working electrode, act as the pH-sensitive membrane was connected to a commercial metal-oxide semiconductor FET (MOSFET). This MOSFET then was connected to the interfacing circuit. The sensitivity of the TiO2 thin film towards pH buffer solution was measured by dipping the sensing membrane in pH4, pH7 and pH10 buffer solution. These thin films were characterized by using Field Emission Scanning Electron Microscope (FESEM) to obtain the surface morphology of the composite bilayer films. In addition, I-V measurement was done in order to determine the electrical properties of the bilayer films. According to the result obtained in this experiment, bilayer film that spin at 4000 rpm, gave highest sensitivity which is 52.1 mV/pH. Relating the I-V characteristic of the thin films and sensitivity, the sensing membrane with higher conductivity gave better sensitivity.

Characteristics of TiO{sub 2}/ZnO bilayer film towards pH sensitivity prepared by different spin coating deposition process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rahman, Rohanieza Abdul, E-mail: rohanieza.abdrahman@gmail.com; Zulkefle, Muhammad Al Hadi, E-mail: alhadizulkefle@gmail.com; Abdullah, Wan Fazlida Hanim, E-mail: wanfaz@salam.uitm.edu.my

In this study, titanium dioxide (TiO{sub 2}) and zinc oxide (ZnO) bilayer film for pH sensing application will be presented. TiO{sub 2}/ZnO bilayer film with different speed of spin-coating process was deposited on Indium Tin Oxide (ITO), prepared by sol-gel method. This fabricated bilayer film was used as sensing membrane for Extended Gate Field-Effect Transistor (EGFET) for pH sensing application. Experimental results indicated that the sensor is able to detect the sensitivity towards pH buffer solution. In order to obtained the result, sensitivity measurement was done by using the EGFET setup equipment with constant-current (100 µA) and constant-voltage (0.3 V)more » biasing interfacing circuit. TiO{sub 2}/ZnO bilayer film which the working electrode, act as the pH-sensitive membrane was connected to a commercial metal-oxide semiconductor FET (MOSFET). This MOSFET then was connected to the interfacing circuit. The sensitivity of the TiO2 thin film towards pH buffer solution was measured by dipping the sensing membrane in pH4, pH7 and pH10 buffer solution. These thin films were characterized by using Field Emission Scanning Electron Microscope (FESEM) to obtain the surface morphology of the composite bilayer films. In addition, I-V measurement was done in order to determine the electrical properties of the bilayer films. According to the result obtained in this experiment, bilayer film that spin at 4000 rpm, gave highest sensitivity which is 52.1 mV/pH. Relating the I-V characteristic of the thin films and sensitivity, the sensing membrane with higher conductivity gave better sensitivity.« less

Generation of propagating backward volume spin waves by phase-sensitive mode conversion in two-dimensional microstructures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Braecher, T.; Sebastian, T.; Graduate School Materials Science in Mainz, Gottlieb-Daimler-Strasse 47, D-67663 Kaiserslautern

2013-04-01

We present the generation of propagating backward volume (BV) spin waves in a T shaped Ni{sub 81}Fe{sub 19} microstructure. These waves are created from counterpropagating Damon Eshbach spin waves, which are excited using microstrip antennas. By employing Brillouin light scattering microscopy, we show how the phase relation between the counterpropagating waves determines the mode generated in the center of the structure, and prove its propagation inside the longitudinally magnetized part of the T shaped microstructure. This gives access to the effective generation of backward volume spin waves with full control over the generated transverse mode.

Final Technical Report for DE-SC0008149

DOE Office of Scientific and Technical Information (OSTI.GOV)

Buchanan, Kristen

The major goal of this project is to study spin waves in magnetic thin films, especially how spin waves respond to external stimuli. This is expected to lead to new insight into dynamic processes and new ideas for methods to control spin waves. Experimental studies are being done primarily using time- and spatially-resolved Brillouin light scattering (BLS) measurements on extended and patterned magnetic thin films. BLS is a versatile tool that provides a non-invasive probe of spin dynamics with frequencies of ~1 GHz to well over 100 GHz, diffraction-limited spatial resolution, 250-ps temporal resolution, and it is sensitive enough tomore » detect thermal magnons.« less

Preparation, fabrication and biocompatibility of novel injectable temperature-sensitive chitosan/glycerophosphate/collagen hydrogels.

PubMed

Song, Kedong; Qiao, Mo; Liu, Tianqing; Jiang, Bo; Macedo, Hugo M; Ma, Xuehu; Cui, Zhanfeng

2010-10-01

This paper introduces a novel type of injectable temperature-sensitive chitosan/glycerophosphate/collagen (C/GP/Co) hydrogel that possesses great biocompatibility for the culture of adipose tissue-derived stem cells. The C/GP/Co hydrogel is prepared by mixing 2.2% (v/v) chitosan with 50% (w/w) β-glycerophosphate at different proportions and afterwards adding 2 mg/ml of collagen. The gelation time of the prepared solution at 37°C was found to be of around 12 min. The inner structure of the hydrogel presented a porous spongy structure, as observed by scanning electron microscopy. Moreover, the osmolality of the medium in contact with the hydrogel was in the range of 310-330 mmol kg(-1). These analyses have shown that the C/GP/Co hydrogels are structurally feasible for cell culture, while their biocompatibility was further examined. Human adipose tissue-derived stem cells (ADSCs) were seeded into the developed C/GP and C/GP/Co hydrogels (The ratios of C/GP and C/GP/Co were 5:1 and 5:1:6, respectively), and the cellular growth was periodically observed under an inverted microscope. The proliferation of ADSCs was detected using cck-8 kits, while cell apoptosis was determined by a Live/Dead Viability/Cytotoxicity kit. After 7 days of culture, cells within the C/GP/Co hydrogels displayed a typical adherent cell morphology and good proliferation with very high cellular viability. It was thus demonstrated that the novel C/GP/Co hydrogel herein described possess excellent cellular compatibility, representing a new alternative as a scaffold for tissue engineering, with the added advantage of being a gel at the body's temperature that turns liquid at room temperature.

Macro-spin modeling and experimental study of spin-orbit torque biased magnetic sensors

NASA Astrophysics Data System (ADS)

Xu, Yanjun; Yang, Yumeng; Luo, Ziyan; Xu, Baoxi; Wu, Yihong

2017-11-01

We reported a systematic study of spin-orbit torque biased magnetic sensors based on NiFe/Pt bilayers through both macro-spin modeling and experiments. The simulation results show that it is possible to achieve a linear sensor with a dynamic range of 0.1-10 Oe, power consumption of 1 μW-1mW, and sensitivity of 0.1-0.5 Ω/Oe. These characteristics can be controlled by varying the sensor dimension and current density in the Pt layer. The latter is in the range of 1 × 105-107 A/cm2. Experimental results of fabricated sensors with selected sizes agree well with the simulation results. For a Wheatstone bridge sensor comprising of four sensing elements, a sensitivity up to 0.548 Ω/Oe, linearity error below 6%, and detectivity of about 2.8 nT/√Hz were obtained. The simple structure and ultrathin thickness greatly facilitate the integration of these sensors for on-chip applications. As a proof-of-concept experiment, we demonstrate its application in detection of current flowing in an on-chip Cu wire.

Force-detected nuclear magnetic resonance: recent advances and future challenges.

PubMed

Poggio, M; Degen, C L

2010-08-27

We review recent efforts to detect small numbers of nuclear spins using magnetic resonance force microscopy. Magnetic resonance force microscopy (MRFM) is a scanning probe technique that relies on the mechanical measurement of the weak magnetic force between a microscopic magnet and the magnetic moments in a sample. Spurred by the recent progress in fabricating ultrasensitive force detectors, MRFM has rapidly improved its capability over the last decade. Today it boasts a spin sensitivity that surpasses conventional, inductive nuclear magnetic resonance detectors by about eight orders of magnitude. In this review we touch on the origins of this technique and focus on its recent application to nanoscale nuclear spin ensembles, in particular on the imaging of nanoscale objects with a three-dimensional (3D) spatial resolution better than 10 nm. We consider the experimental advances driving this work and highlight the underlying physical principles and limitations of the method. Finally, we discuss the challenges that must be met in order to advance the technique towards single nuclear spin sensitivity-and perhaps-to 3D microscopy of molecules with atomic resolution.

Use of rapid-scan EPR to improve detection sensitivity for spin-trapped radicals.

PubMed

Mitchell, Deborah G; Rosen, Gerald M; Tseitlin, Mark; Symmes, Breanna; Eaton, Sandra S; Eaton, Gareth R

2013-07-16

The short lifetime of superoxide and the low rates of formation expected in vivo make detection by standard continuous wave (CW) electron paramagnetic resonance (EPR) challenging. The new rapid-scan EPR method offers improved sensitivity for these types of samples. In rapid-scan EPR, the magnetic field is scanned through resonance in a time that is short relative to electron spin relaxation times, and data are processed to obtain the absorption spectrum. To validate the application of rapid-scan EPR to spin trapping, superoxide was generated by the reaction of xanthine oxidase and hypoxanthine with rates of 0.1-6.0 μM/min and trapped with 5-tert-butoxycarbonyl-5-methyl-1-pyrroline-N-oxide (BMPO). Spin trapping with BMPO to form the BMPO-OOH adduct converts the very short-lived superoxide radical into a more stable spin adduct. There is good agreement between the hyperfine splitting parameters obtained for BMPO-OOH by CW and rapid-scan EPR. For the same signal acquisition time, the signal/noise ratio is >40 times higher for rapid-scan than for CW EPR. Rapid-scan EPR can detect superoxide produced by Enterococcus faecalis at rates that are too low for detection by CW EPR. Copyright © 2013 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Optimization of identity operation in NMR spectroscopy via genetic algorithm: Application to the TEDOR experiment

NASA Astrophysics Data System (ADS)

Manu, V. S.; Veglia, Gianluigi

2016-12-01

Identity operation in the form of π pulses is widely used in NMR spectroscopy. For an isolated single spin system, a sequence of even number of π pulses performs an identity operation, leaving the spin state essentially unaltered. For multi-spin systems, trains of π pulses with appropriate phases and time delays modulate the spin Hamiltonian to perform operations such as decoupling and recoupling. However, experimental imperfections often jeopardize the outcome, leading to severe losses in sensitivity. Here, we demonstrate that a newly designed Genetic Algorithm (GA) is able to optimize a train of π pulses, resulting in a robust identity operation. As proof-of-concept, we optimized the recoupling sequence in the transferred-echo double-resonance (TEDOR) pulse sequence, a key experiment in biological magic angle spinning (MAS) solid-state NMR for measuring multiple carbon-nitrogen distances. The GA modified TEDOR (GMO-TEDOR) experiment with improved recoupling efficiency results in a net gain of sensitivity up to 28% as tested on a uniformly 13C, 15N labeled microcrystalline ubiquitin sample. The robust identity operation achieved via GA paves the way for the optimization of several other pulse sequences used for both solid- and liquid-state NMR used for decoupling, recoupling, and relaxation experiments.

Attitude Ground System (AGS) for the Magnetospheric Multi-Scale (MMS) Mission

NASA Technical Reports Server (NTRS)

Raymond, Juan C.; Sedlak, Joseph E.; Vint, Babak

2015-01-01

MMS Overview Recall from Conrads presentation earlier today MMS launch: March 13, 2015 on an Atlas V from Space Launch Complex 40, Cape Canaveral, Florida MMS Observatory Separation: five minute intervals spinning at 3 rpm approximately 1.5 hours after launch MMS Science Goals: study magnetospheric plasma physics and understand the processes that cause power grids, communication disruptions and Aurora formation Mission: 4 identical spacecraft in tetrahedral formation with variable size1.2 x 12 RE in Phase 1, with apogee on dayside to observe bow shock1.2 x 25 RE in Phase 2, with apogee on night side to observe magneto tail Challenges Tight attitude control box, orbit and formation maintenance requirements Maneuvers on thrusters every two weeks Delta-H Spin axis direction and spin rate maintenance Delta-V Orbit and Formation maintenance Mission phase transitions AGS support Smart targeting prediction of Spin-Axis attitude in the presence of environmental torques to stay within the science attitude Determination of the spacecraft attitude and spin rate (sensitive to knowledge of inertia tensor)Calibrations to improve attitude determination results and improve orbit maneuvers Mass properties (Center of Mass, and inertia tensor for nutation and coning) Accelerometer bias (sensitive to the accuracy of the rate estimates) Sensor alignments.

Natural material-decorated mesoporous silica nanoparticle container for multifunctional membrane-controlled targeted drug delivery

PubMed Central

Hu, Yan; Ke, Lei; Chen, Hao; Zhuo, Ma; Yang, Xinzhou; Zhao, Dan; Zeng, Suying; Xiao, Xincai

2017-01-01

To avoid the side effects caused by nonspecific targeting, premature release, weak selectivity, and poor therapeutic efficacy of current nanoparticle-based systems used for drug delivery, we fabricated natural material-decorated nanoparticles as a multifunctional, membrane-controlled targeted drug delivery system. The nanocomposite material coated with a membrane was biocompatible and integrated both specific tumor targeting and responsiveness to stimulation, which improved transmission efficacy and controlled drug release. Mesoporous silica nanoparticles (MSNs), which are known for their biocompatibility and high drug-loading capacity, were selected as a model drug container and carrier. The membrane was established by the polyelectrolyte composite method from chitosan (CS) which was sensitive to the acidic tumor microenvironment, folic acid-modified CS which recognizes the folate receptor expressed on the tumor cell surface, and a CD44 receptor-targeted polysaccharide hyaluronic acid. We characterized the structure of the nanocomposite as well as the drug release behavior under the control of the pH-sensitive membrane switch and evaluated the antitumor efficacy of the system in vitro. Our results provide a basis for the design and fabrication of novel membrane-controlled nanoparticles with improved tumor-targeting therapy. PMID:29200852

Biological Evaluation of the Copper/Low-density Polyethylene Nanocomposite Intrauterine Device

PubMed Central

Wang, Hong; Li, Jun; Xie, Changsheng; Duan, Zhuo; Sun, Li-Kui; Wang, Xin; Zhu, Changhong

2013-01-01

Devices and materials intended for clinical applications as medical and implant devices should be evaluated to determine their biocompatibility in physiological systems. This article presents results from cytotoxicity assay of L929 mouse fibroblasts culture, tests for skin irritation, intracutaneous reactivity and sensitization, and material implantation tests for the novel copper/low-density polyethylene nanocomposite intrauterine device (nano-Cu/LDPE IUD) with potential for future clinical utilization. Cytotoxicity test in vitro was conducted to evaluate the change in morphology, growth and proliferation of cultured L929 mouse fibroblasts, which in vivo examination for skin irritation (n = 6) and intracutaneous reactivity (n = 6) were carried out to explore the irritant behavior in New Zealand White rabbits. Skin sensitization was implemented to evaluate the potential skin sensitizing in Hartley guinea pigs (n = 35). The materials were implanted into the spinal muscle of rabbits (n = 9). The cytotoxicity grade of the nano-Cu/LDPE IUD was 0–1, suggested that the composite was nontoxic or mildly cytotoxic; no irritation reaction and skin sensitization were identified in any animals of specific extracts prepared from the material under test; similarly to the control sides, the inflammatory reaction was observed in the rabbits living tissue of the implanted material in intramuscular implantation assay. They indicated that the novel composite intrauterine device presented potential for this type of application because they meet the requirements of the standard practices recommended for evaluating the biological reactivity. The nano-Cu/LDPE IUD has good biocompatibility, which is biologically safe for the clinical research as a novel contraceptive device. PMID:24058521

Biological evaluation of the copper/low-density polyethylene nanocomposite intrauterine device.

PubMed

Hu, Li-Xia; He, Jing; Hou, Li; Wang, Hong; Li, Jun; Xie, Changsheng; Duan, Zhuo; Sun, Li-Kui; Wang, Xin; Zhu, Changhong

2013-01-01

Devices and materials intended for clinical applications as medical and implant devices should be evaluated to determine their biocompatibility in physiological systems. This article presents results from cytotoxicity assay of L929 mouse fibroblasts culture, tests for skin irritation, intracutaneous reactivity and sensitization, and material implantation tests for the novel copper/low-density polyethylene nanocomposite intrauterine device (nano-Cu/LDPE IUD) with potential for future clinical utilization. Cytotoxicity test in vitro was conducted to evaluate the change in morphology, growth and proliferation of cultured L929 mouse fibroblasts, which in vivo examination for skin irritation (n = 6) and intracutaneous reactivity (n = 6) were carried out to explore the irritant behavior in New Zealand White rabbits. Skin sensitization was implemented to evaluate the potential skin sensitizing in Hartley guinea pigs (n = 35). The materials were implanted into the spinal muscle of rabbits (n = 9). The cytotoxicity grade of the nano-Cu/LDPE IUD was 0-1, suggested that the composite was nontoxic or mildly cytotoxic; no irritation reaction and skin sensitization were identified in any animals of specific extracts prepared from the material under test; similarly to the control sides, the inflammatory reaction was observed in the rabbits living tissue of the implanted material in intramuscular implantation assay. They indicated that the novel composite intrauterine device presented potential for this type of application because they meet the requirements of the standard practices recommended for evaluating the biological reactivity. The nano-Cu/LDPE IUD has good biocompatibility, which is biologically safe for the clinical research as a novel contraceptive device.

In Vivo Tumor Vasculature Targeting of CuS@MSN Based Theranostic Nanomedicine.

PubMed

Chen, Feng; Hong, Hao; Goel, Shreya; Graves, Stephen A; Orbay, Hakan; Ehlerding, Emily B; Shi, Sixiang; Theuer, Charles P; Nickles, Robert J; Cai, Weibo

2015-01-01

Actively targeted theranostic nanomedicine may be the key for future personalized cancer management. Although numerous types of theranostic nanoparticles have been developed in the past decade for cancer treatment, challenges still exist in the engineering of biocompatible theranostic nanoparticles with highly specific in vivo tumor targeting capabilities. Here, we report the design, synthesis, surface engineering, and in vivo active vasculature targeting of a new category of theranostic nanoparticle for future cancer management. Water-soluble photothermally sensitive copper sulfide nanoparticles were encapsulated in biocompatible mesoporous silica shells, followed by multistep surface engineering to form the final theranostic nanoparticles. Systematic in vitro targeting, an in vivo long-term toxicity study, photothermal ablation evaluation, in vivo vasculature targeted imaging, biodistribution and histology studies were performed to fully explore the potential of as-developed new theranostic nanoparticles.

Ultraflexible organic amplifier with biocompatible gel electrodes.

PubMed

Sekitani, Tsuyoshi; Yokota, Tomoyuki; Kuribara, Kazunori; Kaltenbrunner, Martin; Fukushima, Takanori; Inoue, Yusuke; Sekino, Masaki; Isoyama, Takashi; Abe, Yusuke; Onodera, Hiroshi; Someya, Takao

2016-04-29

In vivo electronic monitoring systems are promising technology to obtain biosignals with high spatiotemporal resolution and sensitivity. Here we demonstrate the fabrication of a biocompatible highly conductive gel composite comprising multi-walled carbon nanotube-dispersed sheet with an aqueous hydrogel. This gel composite exhibits admittance of 100 mS cm(-2) and maintains high admittance even in a low-frequency range. On implantation into a living hypodermal tissue for 4 weeks, it showed a small foreign-body reaction compared with widely used metal electrodes. Capitalizing on the multi-functional gel composite, we fabricated an ultrathin and mechanically flexible organic active matrix amplifier on a 1.2-μm-thick polyethylene-naphthalate film to amplify (amplification factor: ∼200) weak biosignals. The composite was integrated to the amplifier to realize a direct lead epicardial electrocardiography that is easily spread over an uneven heart tissue.

Generation of spin currents from one-dimensional quantum spin liquid

NASA Astrophysics Data System (ADS)

Hirobe, Daichi; Kawamata, Takayuki; Oyanagi, Koichi; Koike, Yoji; Saitoh, Eiji

2018-03-01

Spin-Seebeck effects (SSEs) in a one-dimensional quantum spin liquid (QSL) system have been investigated in a Sr2CuO3/Pt hybrid structure. Sr2CuO3 contains one-dimensional spin- /1 2 chains in which typical spinons in QSL have been confirmed. Heat-induced voltage measured in a clean Pt/Sr2CuO3 exhibits anomalous sign reversal with decreasing temperature, the negative component of which can be attributed to the spinon-induced SSE. However, the SSE was found to be critically decreased upon the exposure of Sr2CuO3 to air, which can be associated with the chemical degradation of the interface of Sr2CuO3. Despite the drastic change in the SSE signals, properties of the one-dimensional QSL are little changed in the spin susceptibility as well as the thermal conductivity of Sr2CuO3. The SSE signal is also sensitive to the purity of Sr2CuO3; it is suppressed with a decrease in the purity of the primary compounds of the Sr2CuO3. The result indicates that the spinon-induced SSE in Sr2CuO3 is sensitive to the bulk condition due to the one-dimensional atomic channel for spin transport in Sr2CuO3. In a carefully prepared Sr2CuO3/Pt sample, we found that the spinon-induced SSE signal is tolerant to magnetic fields; it increases linearly with the field even up to 9 T. In contrast, SSEs are suppressed under such a high field in ferrimagnetic insulators Y3Fe5O12 or paramagnetic insulators Gd3Ga5O12, which is caused by the Zeeman gap in the spin-wave or paramagnetic spin excitations. The robustness of the spinon-induced SSE is consistent with the Tomonaga-Luttinger liquid theories.

Spin Currents and Ferromagnetic Resonance in Magnetic Thin Films

NASA Astrophysics Data System (ADS)

Ellsworth, David

Spin currents represent a new and exciting phenomenon. There is both a wealth of new physics to be discovered and understood, and many appealing devices which may result from this area of research. To fully realize the potential of this discipline it is necessary to develop new methods for realizing spin currents and explore new materials which may be suitable for spin current applications. Spin currents are an inherently dynamic phenomenon involving the transfer of angular momentum within and between different thin films. In order to understand and optimize such devices the dynamics of magnetization must be determined. This dissertation reports on novel approaches for spin current generation utilizing the magnetic insulators yttrium iron garnet (YIG) and M-type barium hexagonal ferrite (BaM). First, the light-induced spin Seebeck effect is reported for the first time in YIG. Additionally, the first measurement of the spin Seebeck effect without an external magnetic field is demonstrated. To accomplish this the self-biased BaM thin films are utilized. Second, a new method for the generation of spin currents is presented: the photo-spin-voltaic effect. In this new phenomenon, a spin current may be generated by photons in a non-magnetic metal that is in close proximity to a magnetic insulator. On exposure to light, there occurs a light induced, spin-dependent excitation of electrons in a few platinum layers near the metal/magnetic insulator interface. This excitation gives rise to a pure spin current which flows in the metal. This new effect is explored in detail and extensive measurements are carried out to confirm the photonic origin of the photo-spin-voltaic effect and exclude competing effects. In addition to the spin current measurements, magnetization dynamics were probed in thin films using ferromagnetic resonance (FMR). In order to determine the optimal material configuration for magnetic recording write heads, FMR measurements were used to perform damping studies on a set of FeCo samples with different numbers of lamination layers. The use of lamination layers has the potential to tune the damping in such films, while leaving the other magnetic properties unchanged. Finally, the sensitivity of the vector network analyzer FMR technique was improved. The use of field modulation and lock-in detection, along with the background subtraction of a Mach-Zehnder microwave interferometer working as a notch filter, is able to increase the sensitivity and lower the background noise of this measurement technique. This improved system opens the possibility of probing previously difficult samples with extremely low signals.

Dynamical sensitivity control of a single-spin quantum sensor.

PubMed

Lazariev, Andrii; Arroyo-Camejo, Silvia; Rahane, Ganesh; Kavatamane, Vinaya Kumar; Balasubramanian, Gopalakrishnan

2017-07-26

The Nitrogen-Vacancy (NV) defect in diamond is a unique quantum system that offers precision sensing of nanoscale physical quantities at room temperature beyond the current state-of-the-art. The benchmark parameters for nanoscale magnetometry applications are sensitivity, spectral resolution, and dynamic range. Under realistic conditions the NV sensors controlled by conventional sensing schemes suffer from limitations of these parameters. Here we experimentally show a new method called dynamical sensitivity control (DYSCO) that boost the benchmark parameters and thus extends the practical applicability of the NV spin for nanoscale sensing. In contrast to conventional dynamical decoupling schemes, where π pulse trains toggle the spin precession abruptly, the DYSCO method allows for a smooth, analog modulation of the quantum probe's sensitivity. Our method decouples frequency selectivity and spectral resolution unconstrained over the bandwidth (1.85 MHz-392 Hz in our experiments). Using DYSCO we demonstrate high-accuracy NV magnetometry without |2π| ambiguities, an enhancement of the dynamic range by a factor of 4 · 10 3 , and interrogation times exceeding 2 ms in off-the-shelf diamond. In a broader perspective the DYSCO method provides a handle on the inherent dynamics of quantum systems offering decisive advantages for NV centre based applications notably in quantum information and single molecule NMR/MRI.

Spin Noise Detection of Nuclear Hyperpolarization at 1.2 K

PubMed Central

Pöschko, Maria Theresia; Vuichoud, Basile; Milani, Jonas; Bornet, Aurélien; Bechmann, Matthias; Bodenhausen, Geoffrey; Jannin, Sami; Müller, Norbert

2015-01-01

We report proton spin noise spectra of a hyperpolarized solid sample of commonly used “DNP (dynamic nuclear polarization) juice” containing TEMPOL (4-hydroxy-2,2,6,6-tetramethylpiperidine N-oxide) and irradiated by a microwave field at a temperature of 1.2 K in a magnetic field of 6.7 T. The line shapes of the spin noise power spectra are sensitive to the variation of the microwave irradiation frequency and change from dip to bump, when the electron Larmor frequency is crossed, which is shown to be in good accordance with theory by simulations. Small but significant deviations from these predictions are observed, which can be related to spin noise and radiation damping phenomena that have been reported in thermally polarized systems. The non-linear dependence of the spin noise integral on nuclear polarization provides a means to monitor hyperpolarization semi-quantitatively without any perturbation of the spin system by radio frequency irradiation. PMID:26477605

Spin-polarization dependent carrier recombination dynamics and spin relaxation mechanism in asymmetrically doped (110) n-GaAs quantum wells

NASA Astrophysics Data System (ADS)

Teng, Lihua; Jiang, Tianran; Wang, Xia; Lai, Tianshu

2018-05-01

Carrier recombination and electron spin relaxation dynamics in asymmetric n-doped (110) GaAs/AlGaAs quantum wells are investigated with time-resolved pump-probe spectroscopy. The experiment results reveal that the measured carrier recombination time depends strongly on the polarization of pump pulse. With the same pump photon flux densities, the recombination time of spin-polarized carriers is always longer than that of the spin-balanced carriers except at low pump photon flux densities, this anomaly originates from the polarization-sensitive nonlinear absorption effect. Differing from the traditional views, in the low carrier density regime, the D'yakonov-Perel' (DP) mechanism can be more important than the Bir-Aronov-Pikus (BAP) mechanism, since the DP mechanism takes effect, the spin relaxation time in (110) GaAs QWs is shortened obviously via asymmetric doping.

Theoretical study of the density of states and magnetic properties of LaCoO3

NASA Astrophysics Data System (ADS)

Zhuang, Min; Zhang, Weiyi; Hu, Cheng; Ming, Naiben

1998-05-01

The density of states and magnetic properties of low-spin, high-spin, and mixing states of LaCoO3 have been studied within the unrestricted Hartree-Fock approximation. The real-space recursion method is adopted for computing the electronic structure of the disordered system. The paramagnetic high-spin state is dealt with using the usual binary alloy coherent potential approximation (CPA); an extended trinary alloy CPA approximation is developed to describe the mixing state. In agreement with experiments, our results show that the main features of the quasiparticle spectra in the mixing state are not a sensitive function of the high-spin component, but the spectrum does get broadened due to spin scattering. The increasing of the high-spin component also results in a pileup of the density of states at the Fermi energy which indicates an insulator to metal phase transition. Some limitations of the present approach are also discussed.

Neutron Star Spin Measurements and Dense Matter with LOFT

NASA Technical Reports Server (NTRS)

Strohmayer, Tod

2011-01-01

Observations over the last decade with RXTE have begun to reveal the X-ray binary progenitors of the fastest spinning neutron stars presently known. Detection and study of the spin rates of binary neutron stars has important implications for constraining the nature of dense matter present in neutron star interiors, as both the maximum spin rate and mass for neutron stars is set by the equation of state. Precision pulse timing of accreting neutron star binaries can enable mass constraints. Particularly promIsing is the combination of the pulse and eclipse timing, as for example, in systems like Swift 11749.4-2807. With its greater sensitivity, LOFT will enable deeper searches for the spin periods of the neutron stars, both during persistent outburst intervals and thermonuclear X-ray bursts, and enable more precise modeling of detected pulsations. I will explore the anticipated impact of LOFT on spin measurements and its potential for constraining dense matter in neutron stars

Spin-polarized scanning tunneling microscopy experiments on the rough surface of a polycrystalline NiFe film with a fine magnetic tip sensitive to a well-defined magnetization component

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matsuyama, H., E-mail: matsu@phys.sci.hokudai.ac.jp; Nara, D.; Kageyama, R.

We developed a micrometer-sized magnetic tip integrated onto the write head of a hard disk drive for spin-polarized scanning tunneling microscopy (SP-STM) in the modulated tip magnetization mode. Using SP-STM, we measured a well-defined in-plane spin-component of the tunneling current of the rough surface of a polycrystalline NiFe film. The spin asymmetry of the NiFe film was about 1.3% within the bias voltage range of -3 to 1 V. We obtained the local spin component image of the sample surface, switching the magnetic field of the sample to reverse the sample magnetization during scanning. We also obtained a spin imagemore » of the rough surface of a polycrystalline NiFe film evaporated on the recording medium of a hard disk drive.« less

Scanning nuclear resonance imaging of a hyperfine-coupled quantum Hall system.

PubMed

Hashimoto, Katsushi; Tomimatsu, Toru; Sato, Ken; Hirayama, Yoshiro

2018-06-07

Nuclear resonance (NR) is widely used to detect and characterise nuclear spin polarisation and conduction electron spin polarisation coupled by a hyperfine interaction. While the macroscopic aspects of such hyperfine-coupled systems have been addressed in most relevant studies, the essential role of local variation in both types of spin polarisation has been indicated in 2D semiconductor systems. In this study, we apply a recently developed local and highly sensitive NR based on a scanning probe to a hyperfine-coupled quantum Hall (QH) system in a 2D electron gas subject to a strong magnetic field. We succeed in imaging the NR intensity and Knight shift, uncovering the spatial distribution of both the nuclear and electron spin polarisation. The results reveal the microscopic origin of the nonequilibrium QH phenomena, and highlight the potential use of our technique in microscopic studies on various electron spin systems as well as their correlations with nuclear spins.

Application of spin-exchange relaxation-free magnetometry to the Cosmic Axion Spin Precession Experiment

NASA Astrophysics Data System (ADS)

Wang, Tao; Kimball, Derek F. Jackson; Sushkov, Alexander O.; Aybas, Deniz; Blanchard, John W.; Centers, Gary; Kelley, Sean R. O.'; Wickenbrock, Arne; Fang, Jiancheng; Budker, Dmitry

2018-03-01

The Cosmic Axion Spin Precession Experiment (CASPEr) seeks to measure oscillating torques on nuclear spins caused by axion or axion-like-particle (ALP) dark matter via nuclear magnetic resonance (NMR) techniques. A sample spin-polarized along a leading magnetic field experiences a resonance when the Larmor frequency matches the axion/ALP Compton frequency, generating precessing transverse nuclear magnetization. Here we demonstrate a Spin-Exchange Relaxation-Free (SERF) magnetometer with sensitivity ≈ 1 fT /√{ Hz } and an effective sensing volume of 0.1 cm3 that may be useful for NMR detection in CASPEr. A potential drawback of SERF-magnetometer-based NMR detection is the SERF's limited dynamic range. Use of a magnetic flux transformer to suppress the leading magnetic field is considered as a potential method to expand the SERF's dynamic range in order to probe higher axion/ALP Compton frequencies.

Electrically tunable hole g factor of an optically active quantum dot for fast spin rotations

NASA Astrophysics Data System (ADS)

Prechtel, Jonathan H.; Maier, Franziska; Houel, Julien; Kuhlmann, Andreas V.; Ludwig, Arne; Wieck, Andreas D.; Loss, Daniel; Warburton, Richard J.

2015-04-01

We report a large g factor tunability of a single hole spin in an InGaAs quantum dot via an electric field. The magnetic field lies in the in-plane direction x , the direction required for a coherent hole spin. The electrical field lies along the growth direction z and is changed over a large range, 100 kV/cm. Both electron and hole g factors are determined by high resolution laser spectroscopy with resonance fluorescence detection. This, along with the low electrical-noise environment, gives very high quality experimental results. The hole g factor ghx depends linearly on the electric field Fz,d ghx/d Fz=(8.3 ±1.2 ) ×10-4 cm/kV, whereas the electron g factor gex is independent of electric field d gex/d Fz=(0.1 ±0.3 ) ×10-4 cm/kV (results averaged over a number of quantum dots). The dependence of ghx on Fz is well reproduced by a 4 ×4 k .p model demonstrating that the electric field sensitivity arises from a combination of soft hole confining potential, an In concentration gradient, and a strong dependence of material parameters on In concentration. The electric field sensitivity of the hole spin can be exploited for electrically driven hole spin rotations via the g tensor modulation technique and based on these results, a hole spin coupling as large as ˜1 GHz can be envisaged.

Thermal transport in topological-insulator-based superconducting hybrid structures with mixed singlet and triplet pairing states.

PubMed

Li, Hai; Zhao, Yuan Yuan

2017-11-22

In the framework of the Bogoliubov-de Gennes equation, we investigate the thermal transport properties in topological-insulator-based superconducting hybrid structures with mixed spin-singlet and spin-triplet pairing states, and emphasize the different manifestations of the spin-singlet and spin-triplet pairing states in the thermal transport signatures. It is revealed that the temperature-dependent differential thermal conductance strongly depends on the components of the pairing state, and the negative differential thermal conductance only occurs in the spin-singlet pairing state dominated regime. It is also found that the thermal conductance is profoundly sensitive to the components of the pairing state. In the spin-singlet pairing state controlled regime, the thermal conductance obviously oscillates with the phase difference and junction length. With increasing the proportion of the spin-triplet pairing state, the oscillating characteristic of the thermal conductance fades out distinctly. These results suggest an alternative route for distinguishing the components of pairing states in topological-insulator-based superconducting hybrid structures.

Electric-field-induced interferometric resonance of a one-dimensional spin-orbit-coupled electron

PubMed Central

Fan, Jingtao; Chen, Yuansen; Chen, Gang; Xiao, Liantuan; Jia, Suotang; Nori, Franco

2016-01-01

The efficient control of electron spins is of crucial importance for spintronics, quantum metrology, and quantum information processing. We theoretically formulate an electric mechanism to probe the electron spin dynamics, by focusing on a one-dimensional spin-orbit-coupled nanowire quantum dot. Owing to the existence of spin-orbit coupling and a pulsed electric field, different spin-orbit states are shown to interfere with each other, generating intriguing interference-resonant patterns. We also reveal that an in-plane magnetic field does not affect the interval of any neighboring resonant peaks, but contributes a weak shift of each peak, which is sensitive to the direction of the magnetic field. We find that this proposed external-field-controlled scheme should be regarded as a new type of quantum-dot-based interferometry. This interferometry has potential applications in precise measurements of relevant experimental parameters, such as the Rashba and Dresselhaus spin-orbit-coupling strengths, as well as the Landé factor. PMID:27966598

Topological Phase Transitions in the Photonic Spin Hall Effect

DOE PAGES

Kort-Kamp, Wilton Junior de Melo

2017-10-04

The recent synthesis of two-dimensional staggered materials opens up burgeoning opportunities to study optical spin-orbit interactions in semiconducting Dirac-like systems. In this work, we unveil topological phase transitions in the photonic spin Hall effect in the graphene family materials. It is shown that an external static electric field and a high frequency circularly polarized laser allow for active on-demand manipulation of electromagnetic beam shifts. The spin Hall effect of light presents a rich dependence with radiation degrees of freedom, and material properties, and features nontrivial topological properties. Finally, we discover that photonic Hall shifts are sensitive to spin and valleymore » properties of the charge carriers, providing an unprecedented pathway to investigate spintronics and valleytronics in staggered 2D semiconductors.« less

Halogenated Alkyltetrazoles for the Rational Design of FeII Spin-Crossover Materials: Fine-Tuning of the Ligand Size.

PubMed

Müller, Danny; Knoll, Christian; Seifried, Marco; Welch, Jan M; Giester, Gerald; Reissner, Michael; Weinberger, Peter

2018-04-06

1-(3-Halopropyl)-1H-tetrazoles and their corresponding Fe II spin-crossover complexes have been investigated in a combined experimental and theoretical study. Halogen substitution was found to positively influence the spin transition, shifting the transition temperature about 70 K towards room temperature. Halogens located at the ω position were found to be too far away from the coordinating tetrazole moiety to have an electronic impact on the spin transition. The subtle variation of the steric demand of the ligand in a highly comparable series was found to have a comparatively large impact on the spin-transition behavior, which highlights the sensitivity of the effect to subtle structural changes. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Skew Projection of Echo-Detected EPR Spectra for Increased Sensitivity and Resolution

PubMed Central

Bowman, Michael K.; Krzyaniak, Matthew D.; Cruce, Alex A.; Weber, Ralph T.

2013-01-01

The measurement of EPR spectra during pulsed EPR experiments is commonly accomplished by recording the integral of the electron spin echo as the applied magnetic field is stepped through the spectrum. This approach to echo-detected EPR spectral measurement (ED-EPR) limits sensitivity and spectral resolution and can cause gross distortions in the resulting spectra because some of the information present in the electron spin echo is discarded in such measurements. However, Fourier Transformation of echo shapes measured at a series of magnetic field values followed by skew projection onto either a magnetic field or resonance frequency axis can increase both spectral resolution and sensitivity without the need to trade one against the other. Examples of skew-projected spectra with single crystals, glasses and powders show resolution improvements as large as a factor of seven with sensitivity increases of as much as a factor of five. PMID:23644351

High-sensitivity green resist material with organic solvent-free spin-coating and tetramethylammonium hydroxide-free water-developable processes for EB and EUV lithography

NASA Astrophysics Data System (ADS)

Takei, Satoshi; Hanabata, Makoto; Oshima, Akihiro; Kashiwakura, Miki; Kozawa, Takahiro; Tagawa, Seiichi

2015-03-01

We investigated the eco-friendly electron beam (EB) and extreme-ultraviolet (EUV) lithography using a high-sensitive negative type of green resist material derived from biomass to take advantage of organic solvent-free water spin-coating and tetramethylammonium hydroxide(TMAH)-free water-developable techniques. A water developable, non-chemically amplified, high sensitive, and negative tone resist material in EB lithography was developed for environmental affair, safety, easiness of handling, and health of the working people, instead of the common developable process of TMAH. The material design concept to use the water-soluble resist material with acceptable properties such as pillar patterns with less than 100 nm in high EB sensitivity of 10 μC/cm2 and etch selectivity with a silicon-based middle layer in CF4 plasma treatment was demonstrated for EB and EUV lithography.

Skew projection of echo-detected EPR spectra for increased sensitivity and resolution

NASA Astrophysics Data System (ADS)

Bowman, Michael K.; Krzyaniak, Matthew D.; Cruce, Alex A.; Weber, Ralph T.

2013-06-01

The measurement of EPR spectra during pulsed EPR experiments is commonly accomplished by recording the integral of the electron spin echo as the applied magnetic field is stepped through the spectrum. This approach to echo-detected EPR spectral measurement (ED-EPR) limits sensitivity and spectral resolution and can cause gross distortions in the resulting spectra because some of the information present in the electron spin echo is discarded in such measurements. However, Fourier transformation of echo shapes measured at a series of magnetic field values followed by skew projection onto either a magnetic field or resonance frequency axis can increase both spectral resolution and sensitivity without the need to trade one against the other. Examples of skew-projected spectra with single crystals, glasses and powders show resolution improvements as large as a factor of seven with sensitivity increases of as much as a factor of five.

Electrospun PCL/gelatin composite nanofiber structures for effective guided bone regeneration membranes.

PubMed

Ren, Ke; Wang, Yi; Sun, Tao; Yue, Wen; Zhang, Hongyu

2017-09-01

Guided bone regeneration (GBR) membranes have been proved of great benefit for bone tissue engineering due to the improvement of cell attachment and proliferation. To develop GBR membranes with better biocompatibility and more proper degradation ability, here we fabricated polycaprolactone (PCL, polymer)/gelatin (protein) hybrid nanofibrous GBR membranes via electrospinning, followed by crosslinking with genipin. Acetic acid (HAc) was utilized to resolve the phase separation of PCL and gelatin, therefore homogeneous PCL/gelatin hybrid nanofibers with different ratios were successfully prepared. FTIR, XPS, TGA, DSC results proved that the proportion of PCL and gelatin in the as-spun nanofiber membranes could be simply adjusted by changing the weight ratio of PCL and gelatin in the spinning solution. SEM and AFM images demonstrated that all the nanofibers possessed uniform and smooth structures both in two dimension (2D) and three dimension (3D). The mechanical tests showed that these nanofibers exhibited appropriate tensile and strength properties, which were suitable for bone tissue engineering. CCK-8 and SEM images revealed that all the membranes were biocompatible to MC3T3-e1 cells. In addition, the in vitro osteogenesis characterizations, alizarin red in normal medium and osteogenesis medium, indicated that the nanofibers could promote bone formation. Therefore, all these results could suggest that our design of electrospun polymer/protein nanofiber membranes was effective for guided bone regeneration. Copyright © 2017. Published by Elsevier B.V.

Translating textiles to tissue engineering: Creation and evaluation of microporous, biocompatible, degradable scaffolds using industry relevant manufacturing approaches and human adipose derived stem cells.

PubMed

Haslauer, Carla M; Avery, Matthew R; Pourdeyhimi, Behnam; Loboa, Elizabeth G

2015-07-01

Polymeric scaffolds have emerged as a means of generating three-dimensional tissues, such as for the treatment of bone injuries and nonunions. In this study, a fibrous scaffold was designed using the biocompatible, degradable polymer poly-lactic acid in combination with a water dispersible sacrificial polymer, EastONE. Fibers were generated via industry relevant, facile scale-up melt-spinning techniques with an islands-in-the-sea geometry. Following removal of EastONE, a highly porous fiber remained possessing 12 longitudinal channels and pores throughout all internal and external fiber walls. Weight loss and surface area characterization confirmed the generation of highly porous fibers as observed via focused ion beam/scanning electron microscopy. Porous fibers were then knit into a three-dimensional scaffold and seeded with human adipose-derived stem cells (hASC). Confocal microscopy images confirmed hASC attachment to the fiber walls and proliferation throughout the knit structure. Quantification of cell-mediated calcium accretion following culture in osteogenic differentiation medium confirmed hASC differentiation throughout the porous constructs. These results suggest incorporation of a sacrificial polymer within islands-in-the-sea fibers generates a highly porous scaffold capable of supporting stem cell viability and differentiation with the potential to generate large three-dimensional constructs for bone regeneration and/or other tissue engineering applications. © 2014 Wiley Periodicals, Inc.

Nuclear magnetic resonance of laser-polarized noble gases in molecules, materials and organisms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goodson, Boyd McLean

1999-12-01

Conventional nuclear magnetic resonance (NMR) spectroscopy and magnetic resonance imaging (MRI) are fundamentally challenged by the insensitivity that stems from the ordinarily low spin polarization achievable in even the strongest NMR magnets. However, by transferring angular momentum from laser light to electronic and nuclear spins, optical pumping methods can increase the nuclear spin polarization of noble gases by several orders of magnitude, thereby greatly enhancing their NMR sensitivity. This dissertation is primarily concerned with the principles and practice of optically pumped nuclear magnetic resonance (OPNMR). The enormous sensitivity enhancement afforded by optical pumping noble gases can be exploited to permitmore » a variety of novel NMR experiments across many disciplines. Many such experiments are reviewed, including the void-space imaging of organisms and materials, NMR and MRI of living tissues, probing structure and dynamics of molecules in solution and on surfaces, and zero-field NMR and MRI.« less

PRESTO polarization transfer to quadrupolar nuclei: Implications for dynamic nuclear polarization

DOE PAGES

Perras, Frederic A.; Kobayashi, Takeshi; Pruski, Marek

2015-08-04

In this study, we show both experimentally and numerically on a series of model systems that in experiments involving transfer of magnetization from 1H to the quadrupolar nuclei under magic-angle-spinning (MAS), the PRESTO technique consistently outperforms traditionally used cross polarization (CP), affording more quantitative intensities, improved lineshapes, better overall sensitivity, and straightforward optimization. This advantage derives from the fact that PRESTO circumvents the convoluted and uncooperative spin dynamics during the CP transfer under MAS, by replacing the spin-locking of quadrupolar nuclei with a single central transition selective 90° pulse and using a symmetry-based recoupling sequence in the 1H channel. Thismore » is important in the context of dynamic nuclear polarization (DNP) NMR of quadrupolar nuclei, where the efficient transfer of enhanced 1H polarization is desired to obtain the highest sensitivity.« less

Conformation of methyl beta-lactoside bound to the ricin B-chain: Interpretation of transferred nuclear Overhauser effects facilitated by spin simulation and selective deuteration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bevilacqua, V.L.; Thomson, D.S.; Prestegard, J.H.

1990-06-12

Spin simulation and selective deuteration have been used to aid in the interpretation of 1D transferred nuclear Overhauser effect (TRNOE) NMR experiments on ricin B-chain/ligand systems. Application of these methods has revealed a change in the conformation of deuterated methyl beta-lactoside upon binding to the ricin B-chain which results in a slight change in glycosidic torsional angels which appear to dominate in the solution conformation. The combination of simulation and experiment also shows an important sensitivity of TRNOE magnitudes to dissociation rate constants and available spin-diffusion pathways for the ricin B-chain/ligand systems under study. The sensitivity to dissociation rates allowsmore » determination of rate constants for methyl beta-lactoside and methyl beta-galactoside of 50 and 300 s-1, respectively.« less

Enhancing quantum sensing sensitivity by a quantum memory

PubMed Central

Zaiser, Sebastian; Rendler, Torsten; Jakobi, Ingmar; Wolf, Thomas; Lee, Sang-Yun; Wagner, Samuel; Bergholm, Ville; Schulte-Herbrüggen, Thomas; Neumann, Philipp; Wrachtrup, Jörg

2016-01-01

In quantum sensing, precision is typically limited by the maximum time interval over which phase can be accumulated. Memories have been used to enhance this time interval beyond the coherence lifetime and thus gain precision. Here, we demonstrate that by using a quantum memory an increased sensitivity can also be achieved. To this end, we use entanglement in a hybrid spin system comprising a sensing and a memory qubit associated with a single nitrogen-vacancy centre in diamond. With the memory we retain the full quantum state even after coherence decay of the sensor, which enables coherent interaction with distinct weakly coupled nuclear spin qubits. We benchmark the performance of our hybrid quantum system against use of the sensing qubit alone by gradually increasing the entanglement of sensor and memory. We further apply this quantum sensor-memory pair for high-resolution NMR spectroscopy of single 13C nuclear spins. PMID:27506596

Mapping Local Protein Electrostatics by EPR of pH-Sensitive Thiol-Specific Nitroxide† ¶

PubMed Central

Voinov, Maxim A.; Ruuge, Andres; Reznikov, Vladimir A.; Grigor’ev, Igor A.; Smirnov, Alex I.

2013-01-01

A first thiol-specific pH-sensitive nitroxide spin label of the imidazolidine series -methanethiosulfonic acid S-(1-oxyl-2,2,3,5,5-pentamethylimidazolidin-4-ylmethyl) ester (IMTSL) - has been synthesized and characterized. X- (9 GHz) and W-band (94 GHz) EPR spectral parameters of the new spin label in its free form and covalently attached to an amino acid cysteine and a tripeptide glutathione were studied as a function of pH and solvent polarity. pKa value of protonatable tertiary amino group of the spin label was found to be unaffected by other ionizable groups present in side chains of unstructured small peptides. The W-band EPR spectra were shown to allow for pKa determination from precise g-factor measurements. Is has been demonstrated that high accuracy of pKa determination for pH-sensitive nitroxides could be achieved regardless the frequency of measurements or the regime of spin exchange: fast at X-band and slow at W-band. IMTSL was found to react specifically with a model protein - iso-1-cytochrome c from yeast Saccharomyces cerevisiae - giving EPR spectra very similar to those of the most commonly employed cysteine-specific label MTSL. CD data indicated no perturbations to the overall protein structure upon IMTSL labeling. It was found that for IMTSL, giso correlates linearly with Aiso but the slopes are different for the neutral and charged forms of the nitroxide. This finding was attributed to the solvent effects on the spin density at the oxygen atom of the N–O group and on the excitation energy of the oxygen lone-pair orbital. PMID:18426227

Spin-state blockade in Te6+-substituted electron-doped LaCoO3

NASA Astrophysics Data System (ADS)

Tomiyasu, Keisuke; Koyama, Shun-Ichi; Watahiki, Masanori; Sato, Mika; Nishihara, Kazuki; Onodera, Mitsugi; Iwasa, Kazuaki; Nojima, Tsutomu; Yamasaki, Yuuichi; Nakao, Hironori; Murakami, Youichi

2015-03-01

Perovskite-type LaCoO3 (Co3+: d6) is a rare inorganic material with sensitive and characteristic responses among low, intermediate, and high spin states. For example, in insulating nonmagnetic low-spin states below about 20 K, light hole doping (Ni substitution) induces much larger magnetization than expected; over net 10μB/hole (5μB/Ni) for 1μB/hole (1μB/Ni), in which the nearly isolated dopants locally change the surrounding Co low-spin states to magnetic ones and form spin molecules with larger total spin. Further, the former is isotropic, whereas the latter exhibits characteristic anisotropy probably because of Jahn-Teller distortion. In contrast, for electron doping, relatively insensitive spin-state responses were reported, as in LaCo(Ti4+) O3, but are not clarified, and are somewhat controversial. Here, we present macroscopic measurement data of another electron-doped system LaCo(Te6+) O3 and discuss the spin-state responses. This study was financially supported by Grants-in-Aid for Young Scientists (B) (No. 22740209 and 26800174) from the MEXT of Japan.

Limits on Spin-Dependent WIMP-Nucleon Cross Section Obtained from the Complete LUX Exposure

NASA Astrophysics Data System (ADS)

Akerib, D. S.; Alsum, S.; Araújo, H. M.; Bai, X.; Bailey, A. J.; Balajthy, J.; Beltrame, P.; Bernard, E. P.; Bernstein, A.; Biesiadzinski, T. P.; Boulton, E. M.; Brás, P.; Byram, D.; Cahn, S. B.; Carmona-Benitez, M. C.; Chan, C.; Chiller, A. A.; Chiller, C.; Currie, A.; Cutter, J. E.; Davison, T. J. R.; Dobi, A.; Dobson, J. E. Y.; Druszkiewicz, E.; Edwards, B. N.; Faham, C. H.; Fallon, S. R.; Fiorucci, S.; Gaitskell, R. J.; Gehman, V. M.; Ghag, C.; Gilchriese, M. G. D.; Hall, C. R.; Hanhardt, M.; Haselschwardt, S. J.; Hertel, S. A.; Hogan, D. P.; Horn, M.; Huang, D. Q.; Ignarra, C. M.; Jacobsen, R. G.; Ji, W.; Kamdin, K.; Kazkaz, K.; Khaitan, D.; Knoche, R.; Larsen, N. A.; Lee, C.; Lenardo, B. G.; Lesko, K. T.; Lindote, A.; Lopes, M. I.; Manalaysay, A.; Mannino, R. L.; Marzioni, M. F.; McKinsey, D. N.; Mei, D.-M.; Mock, J.; Moongweluwan, M.; Morad, J. A.; Murphy, A. St. J.; Nehrkorn, C.; Nelson, H. N.; Neves, F.; O'Sullivan, K.; Oliver-Mallory, K. C.; Palladino, K. J.; Pease, E. K.; Reichhart, L.; Rhyne, C.; Shaw, S.; Shutt, T. A.; Silva, C.; Solmaz, M.; Solovov, V. N.; Sorensen, P.; Stephenson, S.; Sumner, T. J.; Szydagis, M.; Taylor, D. J.; Taylor, W. C.; Tennyson, B. P.; Terman, P. A.; Tiedt, D. R.; To, W. H.; Tripathi, M.; Tvrznikova, L.; Uvarov, S.; Velan, V.; Verbus, J. R.; Webb, R. C.; White, J. T.; Whitis, T. J.; Witherell, M. S.; Wolfs, F. L. H.; Xu, J.; Yazdani, K.; Young, S. K.; Zhang, C.; LUX Collaboration

2017-06-01

We present experimental constraints on the spin-dependent WIMP-nucleon elastic cross sections from the total 129.5 kg yr exposure acquired by the Large Underground Xenon experiment (LUX), operating at the Sanford Underground Research Facility in Lead, South Dakota (USA). A profile likelihood ratio analysis allows 90% C.L. upper limits to be set on the WIMP-neutron (WIMP-proton) cross section of σn=1.6 ×10-41 cm2 (σp=5 ×10-40 cm2 ) at 35 GeV c-2 , almost a sixfold improvement over the previous LUX spin-dependent results. The spin-dependent WIMP-neutron limit is the most sensitive constraint to date.

Dynamic magnetic hysteresis properties of two-dimensional ferrimagnetic structures containing high-spin (S = 5/2) and low-spin (S = 1/2)

NASA Astrophysics Data System (ADS)

Batı, Mehmet; Ertaş, Mehmet

2017-09-01

The dynamic hysteresis behaviors of a containing high spin-5/2 and low spin-1/2 Ising ferrimagnetic system on a square lattice are studied by using the dynamic mean-field approximation. The influences of the temperature, the single-ion anisotropy and the frequency on dynamic hysteresis behaviors are investigated in detail. Somewhat characteristic behaviors are found, such as the presence of triple hysteresis loop for appropriate values of the crystal field or temperature. Besides, we observed that, hysteresis loop area and phase transition points are very sensitive to changes in frequency and thus have profound importance in device application.

Dark state polarizing a nuclear spin in the vicinity of a nitrogen-vacancy center

NASA Astrophysics Data System (ADS)

Wang, Yang-Yang; Qiu, Jing; Chu, Ying-Qi; Zhang, Mei; Cai, Jianming; Ai, Qing; Deng, Fu-Guo

2018-04-01

The nuclear spin in the vicinity of a nitrogen-vacancy (NV) center possesses long coherence time and convenient manipulation assisted by the strong hyperfine interaction with the NV center. It is suggested for the subsequent quantum information storage and processing after appropriate initialization. However, current experimental schemes are either sensitive to the inclination and magnitude of the magnetic field or require thousands of repetitions to achieve successful realization. Here, we propose a method to polarize a 13C nuclear spin in the vicinity of an NV center via a dark state. We demonstrate theoretically and numerically that it is robust to polarize various nuclear spins with different hyperfine couplings and noise strengths.

Atomic-scale sensing of the magnetic dipolar field from single atoms

NASA Astrophysics Data System (ADS)

Choi, Taeyoung; Paul, William; Rolf-Pissarczyk, Steffen; MacDonald, Andrew J.; Natterer, Fabian D.; Yang, Kai; Willke, Philip; Lutz, Christopher P.; Heinrich, Andreas J.

2017-05-01

Spin resonance provides the high-energy resolution needed to determine biological and material structures by sensing weak magnetic interactions. In recent years, there have been notable achievements in detecting and coherently controlling individual atomic-scale spin centres for sensitive local magnetometry. However, positioning the spin sensor and characterizing spin-spin interactions with sub-nanometre precision have remained outstanding challenges. Here, we use individual Fe atoms as an electron spin resonance (ESR) sensor in a scanning tunnelling microscope to measure the magnetic field emanating from nearby spins with atomic-scale precision. On artificially built assemblies of magnetic atoms (Fe and Co) on a magnesium oxide surface, we measure that the interaction energy between the ESR sensor and an adatom shows an inverse-cube distance dependence (r-3.01±0.04). This demonstrates that the atoms are predominantly coupled by the magnetic dipole-dipole interaction, which, according to our observations, dominates for atom separations greater than 1 nm. This dipolar sensor can determine the magnetic moments of individual adatoms with high accuracy. The achieved atomic-scale spatial resolution in remote sensing of spins may ultimately allow the structural imaging of individual magnetic molecules, nanostructures and spin-labelled biomolecules.

Circuit quantum electrodynamics with a spin qubit.

PubMed

Petersson, K D; McFaul, L W; Schroer, M D; Jung, M; Taylor, J M; Houck, A A; Petta, J R

2012-10-18

Electron spins trapped in quantum dots have been proposed as basic building blocks of a future quantum processor. Although fast, 180-picosecond, two-quantum-bit (two-qubit) operations can be realized using nearest-neighbour exchange coupling, a scalable, spin-based quantum computing architecture will almost certainly require long-range qubit interactions. Circuit quantum electrodynamics (cQED) allows spatially separated superconducting qubits to interact via a superconducting microwave cavity that acts as a 'quantum bus', making possible two-qubit entanglement and the implementation of simple quantum algorithms. Here we combine the cQED architecture with spin qubits by coupling an indium arsenide nanowire double quantum dot to a superconducting cavity. The architecture allows us to achieve a charge-cavity coupling rate of about 30 megahertz, consistent with coupling rates obtained in gallium arsenide quantum dots. Furthermore, the strong spin-orbit interaction of indium arsenide allows us to drive spin rotations electrically with a local gate electrode, and the charge-cavity interaction provides a measurement of the resulting spin dynamics. Our results demonstrate how the cQED architecture can be used as a sensitive probe of single-spin physics and that a spin-cavity coupling rate of about one megahertz is feasible, presenting the possibility of long-range spin coupling via superconducting microwave cavities.

Atomic-Scale Nuclear Spin Imaging Using Quantum-Assisted Sensors in Diamond

NASA Astrophysics Data System (ADS)

Ajoy, A.; Bissbort, U.; Lukin, M. D.; Walsworth, R. L.; Cappellaro, P.

2015-01-01

Nuclear spin imaging at the atomic level is essential for the understanding of fundamental biological phenomena and for applications such as drug discovery. The advent of novel nanoscale sensors promises to achieve the long-standing goal of single-protein, high spatial-resolution structure determination under ambient conditions. In particular, quantum sensors based on the spin-dependent photoluminescence of nitrogen-vacancy (NV) centers in diamond have recently been used to detect nanoscale ensembles of external nuclear spins. While NV sensitivity is approaching single-spin levels, extracting relevant information from a very complex structure is a further challenge since it requires not only the ability to sense the magnetic field of an isolated nuclear spin but also to achieve atomic-scale spatial resolution. Here, we propose a method that, by exploiting the coupling of the NV center to an intrinsic quantum memory associated with the nitrogen nuclear spin, can reach a tenfold improvement in spatial resolution, down to atomic scales. The spatial resolution enhancement is achieved through coherent control of the sensor spin, which creates a dynamic frequency filter selecting only a few nuclear spins at a time. We propose and analyze a protocol that would allow not only sensing individual spins in a complex biomolecule, but also unraveling couplings among them, thus elucidating local characteristics of the molecule structure.

Theoretical treatment of the spin-orbit coupling in the rare gas oxides NeO, ArO, KrO, and XeO

NASA Technical Reports Server (NTRS)

Langhoff, S. R.

1980-01-01

Off-diagonal spin-orbit matrix elements are calculated as a function of internuclear distance for the rare gas oxides NeO, ArO, KrO, and XeO using the full microscopic spin-orbit Hamiltonian, including all one- and two-electron integrals, and POL-CI wave functions comparable to those of Dunning and Hay (1977). A good agreement was found when comparing these results in detail with the calculations of Cohen, Wadt and Hay (1979) that utilize an effective one-electron one-center spin-orbit operator. For the rare gas oxide molecules, it is suggested that the numerical results are a more sensitive test of the wave functions (particularly to the extent of charge transfer) than the exact evaluation of all terms in the full spin-orbit operator.

Direct observation and imaging of a spin-wave soliton with p-like symmetry

NASA Astrophysics Data System (ADS)

Bonetti, S.; Kukreja, R.; Chen, Z.; Macià, F.; Hernàndez, J. M.; Eklund, A.; Backes, D.; Frisch, J.; Katine, J.; Malm, G.; Urazhdin, S.; Kent, A. D.; Stöhr, J.; Ohldag, H.; Dürr, H. A.

2015-11-01

Spin waves, the collective excitations of spins, can emerge as nonlinear solitons at the nanoscale when excited by an electrical current from a nanocontact. These solitons are expected to have essentially cylindrical symmetry (that is, s-like), but no direct experimental observation exists to confirm this picture. Using a high-sensitivity time-resolved magnetic X-ray microscopy with 50 ps temporal resolution and 35 nm spatial resolution, we are able to create a real-space spin-wave movie and observe the emergence of a localized soliton with a nodal line, that is, with p-like symmetry. Micromagnetic simulations explain the measurements and reveal that the symmetry of the soliton can be controlled by magnetic fields. Our results broaden the understanding of spin-wave dynamics at the nanoscale, with implications for the design of magnetic nanodevices.

Development and Validation of Noninvasive Magnetic Resonance Relaxometry for the In Vivo Assessment of Tissue-Engineered Graft Oxygenation

PubMed Central

Einstein, Samuel A.; Weegman, Bradley P.; Firpo, Meri T.; Papas, Klearchos K.

2016-01-01

Techniques to monitor the oxygen partial pressure (pO2) within implanted tissue-engineered grafts (TEGs) are critically necessary for TEG development, but current methods are invasive and inaccurate. In this study, we developed an accurate and noninvasive technique to monitor TEG pO2 utilizing proton (1H) or fluorine (19F) magnetic resonance spectroscopy (MRS) relaxometry. The value of the spin-lattice relaxation rate constant (R1) of some biocompatible compounds is sensitive to dissolved oxygen (and temperature), while insensitive to other external factors. Through this physical mechanism, MRS can measure the pO2 of implanted TEGs. We evaluated six potential MRS pO2 probes and measured their oxygen and temperature sensitivities and their intrinsic R1 values at 16.4 T. Acellular TEGs were constructed by emulsifying porcine plasma with perfluoro-15-crown-5-ether, injecting the emulsion into a macroencapsulation device, and cross-linking the plasma with a thrombin solution. A multiparametric calibration equation containing R1, pO2, and temperature was empirically generated from MRS data and validated with fiber optic (FO) probes in vitro. TEGs were then implanted in a dorsal subcutaneous pocket in a murine model and evaluated with MRS up to 29 days postimplantation. R1 measurements from the TEGs were converted to pO2 values using the established calibration equation and these in vivo pO2 measurements were simultaneously validated with FO probes. Additionally, MRS was used to detect increased pO2 within implanted TEGs that received supplemental oxygen delivery. Finally, based on a comparison of our MRS data with previously reported data, ultra-high-field (16.4 T) is shown to have an advantage for measuring hypoxia with 19F MRS. Results from this study show MRS relaxometry to be a precise, accurate, and noninvasive technique to monitor TEG pO2 in vitro and in vivo. PMID:27758135

Development and Validation of Noninvasive Magnetic Resonance Relaxometry for the In Vivo Assessment of Tissue-Engineered Graft Oxygenation.

PubMed

Einstein, Samuel A; Weegman, Bradley P; Firpo, Meri T; Papas, Klearchos K; Garwood, Michael

2016-11-01

Techniques to monitor the oxygen partial pressure (pO 2 ) within implanted tissue-engineered grafts (TEGs) are critically necessary for TEG development, but current methods are invasive and inaccurate. In this study, we developed an accurate and noninvasive technique to monitor TEG pO 2 utilizing proton ( 1 H) or fluorine ( 19 F) magnetic resonance spectroscopy (MRS) relaxometry. The value of the spin-lattice relaxation rate constant (R 1 ) of some biocompatible compounds is sensitive to dissolved oxygen (and temperature), while insensitive to other external factors. Through this physical mechanism, MRS can measure the pO 2 of implanted TEGs. We evaluated six potential MRS pO 2 probes and measured their oxygen and temperature sensitivities and their intrinsic R 1 values at 16.4 T. Acellular TEGs were constructed by emulsifying porcine plasma with perfluoro-15-crown-5-ether, injecting the emulsion into a macroencapsulation device, and cross-linking the plasma with a thrombin solution. A multiparametric calibration equation containing R 1 , pO 2 , and temperature was empirically generated from MRS data and validated with fiber optic (FO) probes in vitro. TEGs were then implanted in a dorsal subcutaneous pocket in a murine model and evaluated with MRS up to 29 days postimplantation. R 1 measurements from the TEGs were converted to pO 2 values using the established calibration equation and these in vivo pO 2 measurements were simultaneously validated with FO probes. Additionally, MRS was used to detect increased pO 2 within implanted TEGs that received supplemental oxygen delivery. Finally, based on a comparison of our MRS data with previously reported data, ultra-high-field (16.4 T) is shown to have an advantage for measuring hypoxia with 19 F MRS. Results from this study show MRS relaxometry to be a precise, accurate, and noninvasive technique to monitor TEG pO 2 in vitro and in vivo.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Kuangcai; Lin, Chia -Cheng; Vela, Javier

In this study, three-layer core–shell plasmonic nanorods (Au/Ag/SiO 2–NRs), consisting of a gold nanorod core, a thin silver shell, and a thin silica layer, were synthesized and used as optical imaging probes under a differential interference contrast microscope for single particle orientation and rotational tracking. The localized surface plasmon resonance modes were enhanced upon the addition of the silver shell, and the anisotropic optical properties of gold nanorods were maintained. The silica coating enables surface functionalization with silane coupling agents and provides enhanced stability and biocompatibility. Taking advantage of the longitudinal LSPR enhancement, the orientation and rotational information of themore » hybrid nanorods on synthetic lipid bilayers and on live cell membranes were obtained with millisecond temporal resolution using a scientific complementary metal-oxide-semiconductor camera. The results demonstrate that the as-synthesized hybrid nanorods are promising imaging probes with improved sensitivity and good biocompatibility for single plasmonic particle tracking experiments in biological systems.« less

Piezoelectric ribbons printed onto rubber for flexible energy conversion.

PubMed

Qi, Yi; Jafferis, Noah T; Lyons, Kenneth; Lee, Christine M; Ahmad, Habib; McAlpine, Michael C

2010-02-10

The development of a method for integrating highly efficient energy conversion materials onto stretchable, biocompatible rubbers could yield breakthroughs in implantable or wearable energy harvesting systems. Being electromechanically coupled, piezoelectric crystals represent a particularly interesting subset of smart materials that function as sensors/actuators, bioMEMS devices, and energy converters. Yet, the crystallization of these materials generally requires high temperatures for maximally efficient performance, rendering them incompatible with temperature-sensitive plastics and rubbers. Here, we overcome these limitations by presenting a scalable and parallel process for transferring crystalline piezoelectric nanothick ribbons of lead zirconate titanate from host substrates onto flexible rubbers over macroscopic areas. Fundamental characterization of the ribbons by piezo-force microscopy indicates that their electromechanical energy conversion metrics are among the highest reported on a flexible medium. The excellent performance of the piezo-ribbon assemblies coupled with stretchable, biocompatible rubber may enable a host of exciting avenues in fundamental research and novel applications.

Ultraflexible organic amplifier with biocompatible gel electrodes

PubMed Central

Sekitani, Tsuyoshi; Yokota, Tomoyuki; Kuribara, Kazunori; Kaltenbrunner, Martin; Fukushima, Takanori; Inoue, Yusuke; Sekino, Masaki; Isoyama, Takashi; Abe, Yusuke; Onodera, Hiroshi; Someya, Takao

2016-01-01

In vivo electronic monitoring systems are promising technology to obtain biosignals with high spatiotemporal resolution and sensitivity. Here we demonstrate the fabrication of a biocompatible highly conductive gel composite comprising multi-walled carbon nanotube-dispersed sheet with an aqueous hydrogel. This gel composite exhibits admittance of 100 mS cm−2 and maintains high admittance even in a low-frequency range. On implantation into a living hypodermal tissue for 4 weeks, it showed a small foreign-body reaction compared with widely used metal electrodes. Capitalizing on the multi-functional gel composite, we fabricated an ultrathin and mechanically flexible organic active matrix amplifier on a 1.2-μm-thick polyethylene-naphthalate film to amplify (amplification factor: ∼200) weak biosignals. The composite was integrated to the amplifier to realize a direct lead epicardial electrocardiography that is easily spread over an uneven heart tissue. PMID:27125910

Invited Review Article: Review of centrifugal microfluidic and bio-optical disks

PubMed Central

Nolte, David D.

2009-01-01

Spinning biodisks have advantages that make them attractive for specialized biochip applications. The two main classes of spinning biodisks are microfluidic disks and bio-optical compact disks (BioCD). Microfluidic biodisks take advantage of noninertial pumping for lab-on-a-chip devices using noninertial valves and switches under centrifugal and Coriolis forces to distribute fluids about the disks. BioCDs use spinning-disk interferometry, under the condition of common-path phase quadrature, to perform interferometric label-free detection of molecular recognition and binding. The optical detection of bound molecules on a disk is facilitated by rapid spinning that enables high-speed repetitive sampling to eliminate 1∕f noise through common-mode rejection of intensity fluctuations and extensive signal averaging. Multiple quadrature classes have been developed, such as microdiffraction, in-line, phase contrast, and holographic adaptive optics. Thin molecular films are detected through the surface dipole density with a surface height sensitivity for the detection of protein spots that is approximately 1 pm. This sensitivity easily resolves a submonolayer of solid-support immobilized antibodies and their antigen targets. Fluorescence and light scattering provide additional optical detection techniques on spinning disks. Immunoassays have been applied to haptoglobin using protein A∕G immobilization of antibodies and to prostate specific antigen. Small protein spots enable scalability to many spots per disk for high-throughput and highly multiplexed immonoassays. PMID:19895047

A nuclear magnetic resonance spectrometer concept for hermetically sealed magic angle spinning investigations on highly toxic, radiotoxic, or air sensitive materials.

PubMed

Martel, L; Somers, J; Berkmann, C; Koepp, F; Rothermel, A; Pauvert, O; Selfslag, C; Farnan, I

2013-05-01

A concept to integrate a commercial high-resolution, magic angle spinning nuclear magnetic resonance (MAS-NMR) probe capable of very rapid rotation rates (70 kHz) in a hermetically sealed enclosure for the study of highly radiotoxic materials has been developed and successfully demonstrated. The concept centres on a conventional wide bore (89 mm) solid-state NMR magnet operating with industry standard 54 mm diameter probes designed for narrow bore magnets. Rotor insertion and probe tuning take place within a hermetically enclosed glovebox, which extends into the bore of the magnet, in the space between the probe and the magnet shim system. Oxygen-17 MAS-NMR measurements demonstrate the possibility of obtaining high quality spectra from small sample masses (~10 mg) of highly radiotoxic material and the need for high spinning speeds to improve the spectral resolution when working with actinides. The large paramagnetic susceptibility arising from actinide paramagnetism in (Th(1-x)U(x))O2 solid solutions gives rise to extensive spinning sidebands and poor resolution at 15 kHz, which is dramatically improved at 55 kHz. The first (17)O MAS-NMR measurements on NpO(2+x) samples spinning at 55 kHz are also reported. The glovebox approach developed here for radiotoxic materials can be easily adapted to work with other hazardous or even air sensitive materials.

Biocompatible hollow polymeric particles produced by a mild solvent- and template free strategy.

PubMed

Rodríguez-Velázquez, Eustolia; Taboada, Pablo; Alatorre-Meda, Manuel

2017-08-31

Macroscopic hollow polymeric particles are attractive materials for various applications such as surgery, food industry, agriculture, etc. However, protocols reporting their synthesis have hitherto made use of organic solvents and/or sacrificial templates, compromising the encapsulation of different bioactive compounds and the process yield. Here, millimeter-size, hollow polymeric particles were synthesized, for the first time, in a solvent- and template free manner onto superhydrophobic surfaces (SHS). The particles were produced upon assembly and double superficial crosslinking of liquid droplets of DNA and methacrylamide chitosan aqueous solutions (CH:MA), leading to liquid-core particles with a hardened hydrogel shell. The particles displayed appealing physical and biological properties. The millimeter-size hydrogel shell, resulting from the double ionic/covalent crosslinking of CH:MA, endowed the hollow particles with softness to the touch and an outstanding structural stability against manipulation by hand and with forceps. Meanwhile, the liquid DNA core guaranteed a biocompatible cell encapsulation followed by a superior release and proliferation of viable cells, as compared to solid CH:MA particles prepared as a blank. Particles with these characteristics show promise for surgical protocols practiced in Tissue Engineering and Regenerative Medicine, where manipulable and biocompatible synthetic implants are often needed to supply living cells and other sensitive bioactive compounds. Copyright © 2017 Elsevier B.V. All rights reserved.

Biocompatible hollow polymeric particles produced by a mild solvent- and template free strategy.

PubMed

Rodríguez-Velázquez, Eustolia; Taboada, Pablo; Alatorre-Meda, Manuel

2017-12-01

Macroscopic hollow polymeric particles are attractive materials for various applications such as surgery, food industry, agriculture, etc. However, protocols reporting their synthesis have hitherto made use of organic solvents and/or sacrificial templates, compromising the encapsulation of different bioactive compounds and the process yield. Here, millimeter-size, hollow polymeric particles were synthesized, for the first time, in a solvent- and template free manner onto superhydrophobic surfaces (SHS). The particles were produced upon assembly and double superficial crosslinking of liquid droplets of DNA and methacrylamide chitosan aqueous solutions (CH:MA), leading to liquid-core particles with a hardened hydrogel shell. The particles displayed appealing physical and biological properties. The millimeter-size hydrogel shell, resulting from the double ionic/covalent crosslinking of CH:MA, endowed the hollow particles with softness to the touch and an outstanding structural stability against manipulation by hand and with forceps. Meanwhile, the liquid DNA core guaranteed a biocompatible cell encapsulation followed by a superior release and proliferation of viable cells, as compared to solid CH:MA particles prepared as a blank. Particles with these characteristics show promise for surgical protocols practiced in Tissue Engineering and Regenerative Medicine, where manipulable and biocompatible synthetic implants are often needed to supply living cells and other sensitive bioactive compounds. Copyright © 2017. Published by Elsevier B.V.

Biocompatible astaxanthin as novel contrast agent for biomedical imaging.

PubMed

Nguyen, Van Phuc; Park, Suhyun; Oh, Junghwan; Wook Kang, Hyun

2017-08-01

Photoacoustic imaging (PAI) is a hybrid imaging modality with high resolution and sensitivity that can be beneficial for cancer staging. Due to insufficient endogenous photoacoustic (PA) contrast, the development of exogenous agents is critical in targeting cancerous tumors. The current study demonstrates the feasibility of marine-oriented material, astaxanthin, as a biocompatible PA contrast agent. Both silicon tubing phantoms and ex vivo bladder tissues are tested at various concentrations (up to 5 mg/ml) of astaxanthin to quantitatively explore variations in PA responses. A Q-switched Nd : YAG laser (λ = 532 nm) in conjunction with a 5 MHz ultrasound transducer is employed to generate and acquire PA signals from the samples. The phantom results presented that the PA signal amplitudes increase linearly with the astaxanthin concentrations (threshold detection = 0.31 mg/ml). The tissue injected with astaxanthin yields up to 16-fold higher PA signals, compared with that with saline. Due to distribution of the injected astaxanthin, PAI can image the margin of astaxanthin boles as well as quantify their volume in 3D reconstruction. Further investigations on selective tumor targeting are required to validate astaxanthin as a potential biocompatible contrast agent for PAI-assisted bladder cancer detection. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Dye-Sensitized Core/Active Shell Upconversion Nanoparticles for Optogenetics and Bioimaging Applications

DOE PAGES

Wu, Xiang; Zhang, Yuanwei; Takle, Kendra; ...

2016-01-06

A near-infrared (NIR) dye-sensitized upconversion nanoparticles (UCNPs) can broaden the absorption range and boost upconversion efficiency of UCNPs. We achieved significantly enhanced upconversion luminescence in dye-sensitized core/active shell UCNPs via the doping of ytterbium ions (Yb 3+ ) in the UCNP shell, which bridged the energy transfer from the dye to the UCNP core. As a result, we synergized the two most practical upconversion booster effectors (dye-sensitizing and core/shell enhancement) to amplify upconversion efficiency. We also demonstrated two biomedical applications using these UCNPs. By using dye-sensitized core/active shell UCNP embedded poly(methyl methacrylate) polymer implantable systems, we successfully shifted the optogeneticmore » neuron excitation window to a biocompatible and deep tissue penetrable 800 nm wavelength. Furthermore, UCNPs were water-solubilized with Pluronic F127 with high upconversion efficiency and can be imaged in a mouse model.« less

Trityl radicals in perfluorocarbon emulsions as stable, sensitive, and biocompatible oximetry probes.

PubMed

Dhimitruka, Ilirian; Alzarie, Yasmin Alsayed; Hemann, Craig; Samouilov, Alexandre; Zweier, Jay L

2016-12-01

EPR oximetry with the use of trityl radicals can enable sensitive O 2 measurement in biological cells and tissues. However, in vitro cellular and in vivo biological applications are limited by rapid trityl probe degradation or biological clearance and the need to enhance probe O 2 sensitivity. We synthesized novel perfluorocarbon (PFC) emulsions, ∼200nm droplet size, containing esterified perchlorinated triphenyl methyl (PTM) radicals dispersed in physiological aqueous buffers. These formulations exhibit excellent EPR signal stability, over 20-fold greater than free PTM probes, with high oxygen sensitivity ∼17mG/mmHg enabling pO 2 measurement in aqueous solutions or cell suspensions with sensitivity >0.5mmHg. Thus, PFC-PTM probes hold great promise to enable combined O 2 delivery and sensing as needed to restore or enhance tissue oxygenation in disease. Copyright © 2016 Elsevier Ltd. All rights reserved.

To perform a gyro test of general relativity in a satellite and develop associated control technology

NASA Technical Reports Server (NTRS)

Fairbank, W. M.; Everitt, C. W. F.; Debra, D. B.

1974-01-01

Performance tests of gyroscope operations and gyroscope readout equipment are discussed. The gyroscope was tested for 400 hours at liquid helium temperatures with spin speeds up to 30 Hz. Readout by observing trapped magnetic flux in the spinning rotor with a sensitive magnetometer was accomplished. Application of the gyroscope to space probes and shuttle vehicles.

Highly sensitive free radical detection by nitrone-functionalized gold nanoparticles

NASA Astrophysics Data System (ADS)

Du, Libo; Huang, Saipeng; Zhuang, Qianfen; Jia, Hongying; Rockenbauer, Antal; Liu, Yangping; Liu, Ke Jian; Liu, Yang

2014-01-01

The detection of free radicals and related species has attracted significant attention in recent years because of their critical roles in physiological and pathological processes. Among the methods for the detection of free radicals, electron spin resonance (ESR) coupled with the use of the spin trapping technique has been an effective approach for characterization and quantification of these species due to its high specificity. However, its application in biological systems, especially in in vivo systems, has been greatly limited partially due to the low reaction rate between the currently available spin traps with biological radicals. To overcome this drawback, we herein report the first example of nitrone functionalized gold nanoparticles (Au@EMPO) as highly efficient spin traps in which the thiolated EMPO (2-(ethoxycarbonyl)-2-methyl-3,4-dihydro-2H-pyrrole 1-oxide) derivative was self-assembled on gold nanoparticles. Kinetic studies showed that Au@EMPO has a 137-fold higher reaction rate constant with &z.rad;OH than PBN (N-tert-butyl-α-phenylnitrone). Owing to the high rate of trapping &z.rad;OH by Au@EMPO as well as the high stability of the resulting spin adduct (t1/2 ~ 56 min), Au@EMPO affords 124-fold higher sensitivity for &z.rad;OH than EMPO. Thus, this new nanospin trap shows great potential in trapping the important radicals such as &z.rad;OH in various biological systems and provides a novel strategy to design spin traps with much improved properties.The detection of free radicals and related species has attracted significant attention in recent years because of their critical roles in physiological and pathological processes. Among the methods for the detection of free radicals, electron spin resonance (ESR) coupled with the use of the spin trapping technique has been an effective approach for characterization and quantification of these species due to its high specificity. However, its application in biological systems, especially in in vivo systems, has been greatly limited partially due to the low reaction rate between the currently available spin traps with biological radicals. To overcome this drawback, we herein report the first example of nitrone functionalized gold nanoparticles (Au@EMPO) as highly efficient spin traps in which the thiolated EMPO (2-(ethoxycarbonyl)-2-methyl-3,4-dihydro-2H-pyrrole 1-oxide) derivative was self-assembled on gold nanoparticles. Kinetic studies showed that Au@EMPO has a 137-fold higher reaction rate constant with &z.rad;OH than PBN (N-tert-butyl-α-phenylnitrone). Owing to the high rate of trapping &z.rad;OH by Au@EMPO as well as the high stability of the resulting spin adduct (t1/2 ~ 56 min), Au@EMPO affords 124-fold higher sensitivity for &z.rad;OH than EMPO. Thus, this new nanospin trap shows great potential in trapping the important radicals such as &z.rad;OH in various biological systems and provides a novel strategy to design spin traps with much improved properties. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr04559e

Topological Magnonics: A Paradigm for Spin-Wave Manipulation and Device Design

NASA Astrophysics Data System (ADS)

Wang, X. S.; Zhang, H. W.; Wang, X. R.

2018-02-01

Conventional magnonic devices use magnetostatic waves whose properties are sensitive to device geometry and the details of magnetization structure, so the design and the scalability of the device or circuitry are difficult. We propose topological magnonics, in which topological exchange spin waves are used as information carriers, that do not suffer from conventional problems of magnonic devices with additional nice features of nanoscale wavelength and high frequency. We show that a perpendicularly magnetized ferromagnet on a honeycomb lattice is generically a topological magnetic material in the sense that topologically protected chiral edge spin waves exist in the band gap as long as a spin-orbit-induced nearest-neighbor pseudodipolar interaction (and/or a next-nearest-neighbor Dzyaloshinskii-Moriya interaction) is present. The edge spin waves propagate unidirectionally along sample edges and domain walls regardless of the system geometry and defects. As a proof of concept, spin-wave diodes, spin-wave beam splitters, and spin-wave interferometers are designed by using sample edges and domain walls to manipulate the propagation of topologically protected chiral spin waves. Since magnetic domain walls can be controlled by magnetic fields or electric current or fields, one can essentially draw, erase, and redraw different spin-wave devices and circuitry on the same magnetic plate so that the proposed devices are reconfigurable and tunable. The topological magnonics opens up an alternative direction towards a robust, reconfigurable and scalable spin-wave circuitry.

Variable Coupling Scheme for High Frequency Electron Spin Resonance Resonators Using Asymmetric Meshes

PubMed Central

Tipikin, D. S.; Earle, K. A.; Freed, J. H.

2010-01-01

The sensitivity of a high frequency electron spin resonance (ESR) spectrometer depends strongly on the structure used to couple the incident millimeter wave to the sample that generates the ESR signal. Subsequent coupling of the ESR signal to the detection arm of the spectrometer is also a crucial consideration for achieving high spectrometer sensitivity. In previous work, we found that a means for continuously varying the coupling was necessary for attaining high sensitivity reliably and reproducibly. We report here on a novel asymmetric mesh structure that achieves continuously variable coupling by rotating the mesh in its own plane about the millimeter wave transmission line optical axis. We quantify the performance of this device with nitroxide spin-label spectra in both a lossy aqueous solution and a low loss solid state system. These two systems have very different coupling requirements and are representative of the range of coupling achievable with this technique. Lossy systems in particular are a demanding test of the achievable sensitivity and allow us to assess the suitability of this approach for applying high frequency ESR to the study of biological systems at physiological conditions, for example. The variable coupling technique reported on here allows us to readily achieve a factor of ca. 7 improvement in signal to noise at 170 GHz and a factor of ca. 5 at 95 GHz over what has previously been reported for lossy samples. PMID:20458356

Inflammation-sensitive in situ smart scaffolding for regenerative medicine.

PubMed

Patra, Hirak K; Sharma, Yashpal; Islam, Mohammad Mirazul; Jafari, Mohammad Javad; Murugan, N Arul; Kobayashi, Hisatoshi; Turner, Anthony P F; Tiwari, Ashutosh

2016-10-06

To cope with the rapid evolution of the tissue engineering field, it is now essential to incorporate the use of on-site responsive scaffolds. Therefore, it is of utmost importance to find new 'Intelligent' biomaterials that can respond to the physicochemical changes in the microenvironment. In this present report, we have developed biocompatible stimuli responsive polyaniline-multiwalled carbon nanotube/poly(N-isopropylacrylamide), (PANI-MWCNT/PNIPAm) composite nanofiber networks and demonstrated the physiological temperature coordinated cell grafting phenomenon on its surface. The composite nanofibers were prepared by a two-step process initiated with an assisted in situ polymerization followed by electrospinning. To obtain a smooth surface in individual nanofibers with the thinnest diameter, the component ratios and electrospinning conditions were optimized. The temperature-gated rearrangements of the molecular structure are characterized by FTIR spectroscopy with simultaneous macromolecular architecture changes reflected on the surface morphology, average diameter and pore size as determined by scanning electron microscopy. The stimuli responsiveness of the nanofibers has first been optimized with computational modeling of temperature sensitive components (coil-like and globular conformations) to tune the mechanism for temperature dependent interaction during in situ scaffolding with the cell membrane. The nanofiber networks show excellent biocompatibility, tested with fibroblasts and also show excellent sensitivity to inflammation to combat loco-regional acidosis that delay the wound healing process by an in vitro model that has been developed for testing the proposed responsiveness of the composite nanofiber networks. Cellular adhesion and detachment are regulated through physiological temperature and show normal proliferation of the grafted cells on the composite nanofibers. Thus, we report for the first time, the development of physiological temperature gated inflammation-sensitive smart biomaterials for advanced tissue regeneration and regenerative medicine.

Optimizing a dynamical decoupling protocol for solid-state electronic spin ensembles in diamond

DOE Office of Scientific and Technical Information (OSTI.GOV)

Farfurnik, D.; Jarmola, A.; Pham, L. M.

2015-08-24

In this study, we demonstrate significant improvements of the spin coherence time of a dense ensemble of nitrogen-vacancy (NV) centers in diamond through optimized dynamical decoupling (DD). Cooling the sample down to 77 K suppresses longitudinal spin relaxation T 1 effects and DD microwave pulses are used to increase the transverse coherence time T 2 from ~0.7ms up to ~30ms. Furthermore, we extend previous work of single-axis (Carr-Purcell-Meiboom-Gill) DD towards the preservation of arbitrary spin states. Following a theoretical and experimental characterization of pulse and detuning errors, we compare the performance of various DD protocols. We also identify that themore » optimal control scheme for preserving an arbitrary spin state is a recursive protocol, the concatenated version of the XY8 pulse sequence. The improved spin coherence might have an immediate impact on improvements of the sensitivities of ac magnetometry. Moreover, the protocol can be used on denser diamond samples to increase coherence times up to NV-NV interaction time scales, a major step towards the creation of quantum collective NV spin states.« less

Current-Tunable NbTiN Coplanar Photonic Bandgap Resonators

NASA Astrophysics Data System (ADS)

Asfaw, A.; Sigillito, A. J.; Tyryshkin, A. M.; Lyon, S. A.

Coplanar waveguide resonators have been used in several experimental settings, from superconducting qubits to electron spin resonance. In our particular application of electron spin resonance, these resonators provide increased sensitivity to electron spins due to the small mode volume. Experiments have shown that these resonators can be used to readout as few as 300 spins per shot. Recently, photonic bandgap resonators have been shown to extend the advantages of traditional CPW resonators by allowing spin manipulation both at microwave and radio frequencies, thereby enabling both electron and nuclear spin resonance within the same resonator. We present measurements made using photonic bandgap resonators fabricated with thin NbTiN films which demonstrate microwave tunability of the resonator by modulating the kinetic inductance of the superconductor. Driving a small direct current through the center pin of the resonator allows us to tune the resonant frequency by over 30 MHz around 6.4 GHz while maintaining a quality factor over 8000 at 4.8K. This provides fast and simple tunability of coplanar waveguide resonators and opens new possibilities for multiple frequency electron spin resonance experiments.

Theoretical model of dynamic spin polarization of nuclei coupled to paramagnetic point defects in diamond and silicon carbide

NASA Astrophysics Data System (ADS)

Ivády, Viktor; Szász, Krisztián; Falk, Abram L.; Klimov, Paul V.; Christle, David J.; Janzén, Erik; Abrikosov, Igor A.; Awschalom, David D.; Gali, Adam

2015-09-01

Dynamic nuclear spin polarization (DNP) mediated by paramagnetic point defects in semiconductors is a key resource for both initializing nuclear quantum memories and producing nuclear hyperpolarization. DNP is therefore an important process in the field of quantum-information processing, sensitivity-enhanced nuclear magnetic resonance, and nuclear-spin-based spintronics. DNP based on optical pumping of point defects has been demonstrated by using the electron spin of nitrogen-vacancy (NV) center in diamond, and more recently, by using divacancy and related defect spins in hexagonal silicon carbide (SiC). Here, we describe a general model for these optical DNP processes that allows the effects of many microscopic processes to be integrated. Applying this theory, we gain a deeper insight into dynamic nuclear spin polarization and the physics of diamond and SiC defects. Our results are in good agreement with experimental observations and provide a detailed and unified understanding. In particular, our findings show that the defect electron spin coherence times and excited state lifetimes are crucial factors in the entire DNP process.

Strain-Induced Spin-Resonance Shifts in Silicon Devices

NASA Astrophysics Data System (ADS)

Pla, J. J.; Bienfait, A.; Pica, G.; Mansir, J.; Mohiyaddin, F. A.; Zeng, Z.; Niquet, Y. M.; Morello, A.; Schenkel, T.; Morton, J. J. L.; Bertet, P.

2018-04-01

In spin-based quantum-information-processing devices, the presence of control and detection circuitry can change the local environment of a spin by introducing strain and electric fields, altering its resonant frequencies. These resonance shifts can be large compared to intrinsic spin linewidths, and it is therefore important to study, understand, and model such effects in order to better predict device performance. We investigate a sample of bismuth donor spins implanted in a silicon chip, on top of which a superconducting aluminum microresonator is fabricated. The on-chip resonator provides two functions: it produces local strain in the silicon due to the larger thermal contraction of the aluminum, and it enables sensitive electron spin-resonance spectroscopy of donors close to the surface that experience this strain. Through finite-element strain simulations, we are able to reconstruct key features of our experiments, including the electron spin-resonance spectra. Our results are consistent with a recently observed mechanism for producing shifts of the hyperfine interaction for donors in silicon, which is linear with the hydrostatic component of an applied strain.

Study on the spin-states of cobalt-based double-layer perovskite Sr2Y0.5Ca0.5Co2O7

NASA Astrophysics Data System (ADS)

He, H.; Zhang, W. Y.

2008-02-01

The spin-states of cobalt based perovskite compounds depend sensitively on the valence state and local crystal environment of Co ions and the rich physical properties arise from strong coupling among charge, spin, and orbital degrees of freedom. While extensive studies have been carried out in the past, most of them concentrated on the isotropic compound LaCoO3. In this paper, using the unrestricted Hartree-Fock approximation and the real-space recursion method, we have investigated the competition of various magnetically ordered spin-states of anisotropic double-layered perovskite Sr2Y0.5Ca0.5Co2O7. The energy comparison among these states shows that the nearest-neighbor high-spin-intermediate-spin ferromagnetically ordered state is the relevant magnetic ground state of the compound. The magnetic structure and sizes of magnetic moments are consistent with the recent experimental observation.

Toward the fourth dimension of membrane protein structure: insight into dynamics from spin-labeling EPR spectroscopy.

PubMed

McHaourab, Hassane S; Steed, P Ryan; Kazmier, Kelli

2011-11-09

Trapping membrane proteins in the confines of a crystal lattice obscures dynamic modes essential for interconversion between multiple conformations in the functional cycle. Moreover, lattice forces could conspire with detergent solubilization to stabilize a minor conformer in an ensemble thus confounding mechanistic interpretation. Spin labeling in conjunction with electron paramagnetic resonance (EPR) spectroscopy offers an exquisite window into membrane protein dynamics in the native-like environment of a lipid bilayer. Systematic application of spin labeling and EPR identifies sequence-specific secondary structures, defines their topology and their packing in the tertiary fold. Long range distance measurements (60 Å-80 Å) between pairs of spin labels enable quantitative analysis of equilibrium dynamics and triggered conformational changes. This review highlights the contribution of spin labeling to bridging structure and mechanism. Efforts to develop methods for determining structures from EPR restraints and to increase sensitivity and throughput promise to expand spin labeling applications in membrane protein structural biology. Copyright © 2011 Elsevier Ltd. All rights reserved.

Chaotic nature of the spin-glass phase

NASA Technical Reports Server (NTRS)

Bray, A. J.; Moore, M. A.

1987-01-01

The microscopic structure of the ordered phase of spin glasses is investigated theoretically in the framework of the T = 0 fixed-point model (McMillan, 1984; Fisher and Huse, 1986; and Bray and Moore, 1986). The sensitivity of the ground state to changes in the interaction strengths at T = 0 is explored, and it is found that for sufficiently large length scales the ground state is unstable against arbitrarily weak perturbations to the bonds. Explicit results are derived for d = 1, and the implications for d = 2 and d = 3 are considered in detail. It is concluded that there is no hidden order pattern for spin glasses at all T less than T(C), the ordered-phase spin correlations being chaotic functions of spin separation at fixed temperature or of temperature (for a given pair of spins) at scale lengths L greater than (T delta T) exp -1/zeta, where zeta = d(s)/2 - y, d(s) is the interfacial fractal dimension, and -y is the thermal eigenvalue at T = 0.

Limits on Spin-Dependent WIMP-Nucleon Cross Section Obtained from the Complete LUX Exposure.

PubMed

Akerib, D S; Alsum, S; Araújo, H M; Bai, X; Bailey, A J; Balajthy, J; Beltrame, P; Bernard, E P; Bernstein, A; Biesiadzinski, T P; Boulton, E M; Brás, P; Byram, D; Cahn, S B; Carmona-Benitez, M C; Chan, C; Chiller, A A; Chiller, C; Currie, A; Cutter, J E; Davison, T J R; Dobi, A; Dobson, J E Y; Druszkiewicz, E; Edwards, B N; Faham, C H; Fallon, S R; Fiorucci, S; Gaitskell, R J; Gehman, V M; Ghag, C; Gilchriese, M G D; Hall, C R; Hanhardt, M; Haselschwardt, S J; Hertel, S A; Hogan, D P; Horn, M; Huang, D Q; Ignarra, C M; Jacobsen, R G; Ji, W; Kamdin, K; Kazkaz, K; Khaitan, D; Knoche, R; Larsen, N A; Lee, C; Lenardo, B G; Lesko, K T; Lindote, A; Lopes, M I; Manalaysay, A; Mannino, R L; Marzioni, M F; McKinsey, D N; Mei, D-M; Mock, J; Moongweluwan, M; Morad, J A; Murphy, A St J; Nehrkorn, C; Nelson, H N; Neves, F; O'Sullivan, K; Oliver-Mallory, K C; Palladino, K J; Pease, E K; Reichhart, L; Rhyne, C; Shaw, S; Shutt, T A; Silva, C; Solmaz, M; Solovov, V N; Sorensen, P; Stephenson, S; Sumner, T J; Szydagis, M; Taylor, D J; Taylor, W C; Tennyson, B P; Terman, P A; Tiedt, D R; To, W H; Tripathi, M; Tvrznikova, L; Uvarov, S; Velan, V; Verbus, J R; Webb, R C; White, J T; Whitis, T J; Witherell, M S; Wolfs, F L H; Xu, J; Yazdani, K; Young, S K; Zhang, C

2017-06-23

We present experimental constraints on the spin-dependent WIMP-nucleon elastic cross sections from the total 129.5  kg yr exposure acquired by the Large Underground Xenon experiment (LUX), operating at the Sanford Underground Research Facility in Lead, South Dakota (USA). A profile likelihood ratio analysis allows 90% C.L. upper limits to be set on the WIMP-neutron (WIMP-proton) cross section of σ_{n}=1.6×10^{-41}  cm^{2} (σ_{p}=5×10^{-40}  cm^{2}) at 35  GeV c^{-2}, almost a sixfold improvement over the previous LUX spin-dependent results. The spin-dependent WIMP-neutron limit is the most sensitive constraint to date.

Fabrication of Biopolymer Nanofibers of Hyaluronic Acid via Electrospinning

NASA Astrophysics Data System (ADS)

Young, Denice; Queen, Hailey; Krause, Wendy

2006-03-01

Electrospinning is a novel technology that uses an electric field to form fibrous materials from a polymer solution. Unlike traditional spinning techniques, electrospinning can produce fibers on the order of 100 nm that can be utilized in applications where nanoscale fibers are necessary for successful implementation, including tissue engineering. Hyaluronic acid (HA) is a widely used biopolymer found in the extracellular matrix and currently marketed in medical applications for joint lubrications and tissue engineering. The high viscosity and surface tension of HA make it an unlikely candidate for electrospinning processes as viscosity is an important parameter in successful electrospinning. To promote HA fiber formation by electrospinning, the effects of salt (NaCl), which is used to reduce the viscosity of aqueous HA solutions; molecular weight of the HA; and an additional biocompatible polymer (e.g., PEO) are under investigation.

Multilayer bioactive glass/zirconium titanate thin films in bone tissue engineering and regenerative dentistry

PubMed Central

Mozafari, Masoud; Salahinejad, Erfan; Shabafrooz, Vahid; Yazdimamaghani, Mostafa; Vashaee, Daryoosh; Tayebi, Lobat

2013-01-01

Surface modification, particularly coatings deposition, is beneficial to tissue-engineering applications. In this work, bioactive glass/zirconium titanate composite thin films were prepared by a sol-gel spin-coating method. The surface features of the coatings were studied by scanning electron microscopy, atomic force microscopy, and spectroscopic reflection analyses. The results show that uniform and sound multilayer thin films were successfully prepared through the optimization of the process variables and the application of carboxymethyl cellulose as a dispersing agent. Also, it was found that the thickness and roughness of the multilayer coatings increase nonlinearly with increasing the number of the layers. This new class of nanocomposite coatings, comprising the bioactive and inert components, is expected not only to enhance bioactivity and biocompatibility, but also to protect the surface of metallic implants against wear and corrosion. PMID:23641155

Spin-dependent electron many-body effects in GaAs

NASA Astrophysics Data System (ADS)

Nemec, P.; Kerachian, Y.; van Driel, H. M.; Smirl, Arthur L.

2005-12-01

Time- and polarization-resolved differential transmission measurements employing same and oppositely circularly polarized 150fs optical pulses are used to investigate spin characteristics of conduction band electrons in bulk GaAs at 295K . Electrons and holes with densities in the 2×1016cm-3-1018cm-3 range are generated and probed with pulses whose center wavelength is between 865 and 775nm . The transmissivity results can be explained in terms of the spin sensitivity of both phase-space filling and many-body effects (band-gap renormalization and screening of the Coulomb enhancement factor). For excitation and probing at 865nm , just above the band-gap edge, the transmissivity changes mainly reflect spin-dependent phase-space filling which is dominated by the electron Fermi factors. However, for 775nm probing, the influence of many-body effects on the induced transmission change are comparable with those from reduced phase space filling, exposing the spin dependence of the many-body effects. If one does not take account of these spin-dependent effects one can misinterpret both the magnitude and time evolution of the electron spin polarization. For suitable measurements we find that the electron spin relaxation time is 130ps .

Spin transport in epitaxial graphene

NASA Astrophysics Data System (ADS)

Tbd, -

2014-03-01

Spintronics is a paradigm focusing on spin as the information vector in fast and ultra-low-power non volatile devices such as the new STT-MRAM. Beyond its widely distributed application in data storage it aims at providing more complex architectures and a powerful beyond CMOS solution for information processing. The recent discovery of graphene has opened novel exciting opportunities in terms of functionalities and performances for spintronics devices. We will present experimental results allowing us to assess the potential of graphene for spintronics. We will show that unprecedented highly efficient spin information transport can occur in epitaxial graphene leading to large spin signals and macroscopic spin diffusion lengths (~ 100 microns), a key enabler for the advent of envisioned beyond-CMOS spin-based logic architectures. We will also show that how the device behavior is well explained within the framework of the Valet-Fert drift-diffusion equations. Furthermore, we will show that a thin graphene passivation layer can prevent the oxidation of a ferromagnet, enabling its use in novel humide/ambient low-cost processes for spintronics devices, while keeping its highly surface sensitive spin current polarizer/analyzer behavior and adding new enhanced spin filtering property. These different experiments unveil promising uses of graphene for spintronics.

Topologically protected unidirectional edge spin waves

NASA Astrophysics Data System (ADS)

Wang, Xiang Rong; Wang, Xiansi; Su, Ying

Magnetic materials are highly correlated spin systems that do not respect the time-reversal symmetry. The low-energy excitations of magnetic materials are spin waves whose quanta are magnons. Like electronic materials that can be topologically nontrivial, a magnetic material can also be topologically nontrivial with topologically protected unidirectional edge states. These edge states should be superb channels of processing and manipulating spin waves because they are robust against perturbations and geometry changes, unlike the normal spin wave states that are very sensitive to the system changes and geometry. Therefore, the magnetic topological matter is of fundamental interest and technologically useful in magnonics. Here, we show that ferromagnetically interacting spins on a two-dimensional honeycomb lattice with nearest-neighbour interactions and governed by the Landau-Lifshitz-Gilbert equation, can be topologically nontrivial with gapped bulk spin waves and gapless edge spin waves. These edge spin waves are indeed very robust against defects under topological protection. Because of the unidirectional nature of these topologically protected edge spin waves, an interesting functional magnonic device called beam splitter can be made out of a domain wall in a strip. It is shown that an in-coming spin wave beam along one edge splits into two spin wave beams propagating along two opposite directions on the other edge after passing through a domain wall. This work was supported by Hong Kong GRF Grants (Nos. 163011151 and 16301816) and the Grant from NNSF of China (No. 11374249). X.S.W acknowledge support from UESTC.

Polymeric nanoparticles for optical sensing.

PubMed

Canfarotta, Francesco; Whitcombe, Michael J; Piletsky, Sergey A

2013-12-01

Nanotechnology is a powerful tool for use in diagnostic applications. For these purposes a variety of functional nanoparticles containing fluorescent labels, gold and quantum dots at their cores have been produced, with the aim of enhanced sensitivity and multiplexing capabilities. This work will review progress in the application of polymeric nanoparticles in optical diagnostics, both for in vitro and in vivo detection, together with a discussion of their biodistribution and biocompatibility. © 2013.

Coordination ability determined transition metal ions substitution of Tb in Tb-Asp fluorescent nanocrystals and a facile ions-detection approach.

PubMed

Duan, Jiazhi; Ma, Baojin; Liu, Feng; Zhang, Shan; Wang, Shicai; Kong, Ying; Du, Min; Han, Lin; Wang, Jianjun; Sang, Yuanhua; Liu, Hong

2018-04-26

Although the synthesis and fluorescent properties of lanthanide-amino acid complex nanostructures have been investigated extensively, limited studies have been reported on metal ions' substitution ability for the lanthanide ions in the complex and their effect on the fluorescent property. In this study, taking biocompatible Tb-aspartic acid (Tb-Asp) complex nanocrystals as a model, the substitution mechanism of metal ions, particularly transition metals, for Tb ions in Tb-Asp nanocrystals and the change in the fluorescent property of the Tb-Asp nanocrystals after substitution were systematically investigated. The experimental results illustrated that metal ions with higher electronegativity, higher valence, and smaller radius possess stronger ability for Tb ions' substitution in Tb-Asp nanocrystals. Based on the effect of substituting ions' concentration on the fluorescent property of Tb-Asp, a facile method for copper ions detection with high sensitivity was proposed by measuring the fluorescent intensity of Tb-Asp nanocrystals' suspensions containing different concentrations of copper ions. The good biocompatibility, great convenience of synthesis and sensitive detection ability make Tb-Asp nanocrystals a very low cost and effective material for metal ions detection, which also opens a new door for practical applications of metal-Asp coordinated nanocrystals.

Multienzyme decorated polysaccharide amplified electrogenerated chemiluminescence biosensor for cytosensing and cell surface carbohydrate profiling.

PubMed

Zhang, Ling; Wang, Yangzhong; Tian, Qianqian; Liu, Yang; Li, Jinghong

2017-03-15

A novel ECL biosensor for cytosensing and cell surface carbohydrate expression evaluation was developed, by the integration of the peptide modified interface for highly specific carbohydrate recognition and sodium alginate loaded glucose oxidase as the signal probe with high signal amplification efficiency. A cysteine-terminated peptide self-assembled on the electrode through Au-S bond to construct a functional interface for cell capture, with decent biocompatibility and high affinity for the human breast cancer cell MCF-7. Concanavalin A lectin modified gold nanoparticles specifically recognized the cell surface carbohydrates and were absorbed on the electrode, followed by the immobilization of multiple glucose oxidase conjugated sodium alginate, which could remarkably increase the sensitivity of the biosensor with enhanced catalysis. The as-proposed ECL cytosensor was successfully applied for the detection of the MCF-7 tumor cells, whose glycans on the cell membranes are over-expressed. A low detection limit of 150cellsmL -1 was obtained, with a wide dynamic linear range from 5.0×10 2 to 5.0×10 5 cellsmL -1 . Due to the excellent sensitivity, stability and biocompatibility, the ECL biosensor would be promising in reliable diagnostics of glycan relevant biomarkers for cancer and other diseases. Copyright © 2016 Elsevier B.V. All rights reserved.

Spin exchange optical pumping of neon and its applications

NASA Astrophysics Data System (ADS)

Ghosh, Rajat K.

Hyperpolarized noble gases are used in a variety of applications including medical diagnostic lung imaging, tests of fundamental symmetries, spin filters, atomic gyroscopes, and atomic magnetometers. Typically 3He is utilized because large 3He polarizations on the order of 80% can be achieved. This is accomplished by optically pumping an alkali vapour which polarizes a noble gas nucleus via spin exchange optical pumping. One hyperpolarized noble gas application of particular importance is the K-3He co-magnetometer. Here, the alkali atoms optically pump a diamagnetic noble gas. The magnetic holding field for the alkali and noble gas is reduced until both species are brought into hybrid magnetic resonance. The co-magnetometer exhibits many useful attributes which make it ideal for tests of fundamental physics, such as insensitivity to magnetic fields. The co-magnetometer would demonstrate increased sensitivity by replacing 3He with polarized 21Ne gas. Tests of CPT violation using co-magnetometers would be greatly improved if one utilizes polarized 21Ne gas. The sensitivity of the nuclear spin gyroscope is inversely proportional to the gyromagnetic ratio of the noble gas. Switching to neon would instigate an order of magnitude gain in sensitivity over 3He. In order to realize these applications the interaction parameters of 21Ne with alkali metals must be measured. The spin-exchange cross section sigmase, and magnetic field enhancement factor kappa0 are unknown, and have only been theoretically calculated. There are no quantitative predictions of the neon-neon quadrupolar relaxation rate Gammaquad. In this thesis I test the application of a K-3He co-magnetometer as a navigational gyroscope. I discuss the advantages of switching the buffer gas to 21Ne. I discuss the feasibility of utilizing polarized 21Ne for operation in a co-magnetometer, and construct a prototype 21Ne co-magnetometer. I investigate polarizing 21Ne with optical pumping via spin exchange collisions and measure the spin exchange rate coefficient of K and Rb with Ne to be 2.9 x 10-20cm 3/s and 0.81 x 10-19cm3/s. We measure the magnetic field enhancement factor kappa0 to be 30.8 +/- 2.7, and 35.7 +/- 3.7 for the K-Ne, and the Rb-Ne pair. We measure the quadrupolar relaxation coefficient to be 214 +/- 10 Amagat˙s. Furthermore the spin destruction cross section of Rb, and K with 21 Ne is measured to be 1.9 x 10-23cm2 and 1.1 x 10-23cm2.

Nuclear spin-lattice relaxation in nitroxide spin-label EPR.

PubMed

Marsh, Derek

2016-11-01

Nuclear relaxation is a sensitive monitor of rotational dynamics in spin-label EPR. It also contributes competing saturation transfer pathways in T 1 -exchange spectroscopy, and the determination of paramagnetic relaxation enhancement in site-directed spin labelling. A survey shows that the definition of nitrogen nuclear relaxation rate W n commonly used in the CW-EPR literature for 14 N-nitroxyl spin labels is inconsistent with that currently adopted in time-resolved EPR measurements of saturation recovery. Redefinition of the normalised 14 N spin-lattice relaxation rate, b=W n /(2W e ), preserves the expressions used for CW-EPR, whilst rendering them consistent with expressions for saturation recovery rates in pulsed EPR. Furthermore, values routinely quoted for nuclear relaxation times that are deduced from EPR spectral diffusion rates in 14 N-nitroxyl spin labels do not accord with conventional analysis of spin-lattice relaxation in this three-level system. Expressions for CW-saturation EPR with the revised definitions are summarised. Data on nitrogen nuclear spin-lattice relaxation times are compiled according to the three-level scheme for 14 N-relaxation: T 1 n =1/W n . Results are compared and contrasted with those for the two-level 15 N-nitroxide system. Copyright © 2016 Elsevier Inc. All rights reserved.

Damping of spin-dipole mode and generation of quadrupole mode excitations in a spin-orbit coupled Bose-Einstein condensate

NASA Astrophysics Data System (ADS)

Li, Chuan-Hsun; Blasing, David; Chen, Yong

2017-04-01

In cold atom systems, spin excitations have been shown to be a sensitive probe of interactions and quantum statistical effects, and can be used to study spin transport in both Fermi and Bose gases. In particular, spin-dipole mode (SDM) is a type of excitation that can generate a spin current without a net mass current. We present recent measurements and analysis of SDM in a disorder-free, interacting three-dimensional (3D) 87Rb Bose-Einstein condensate (BEC) by applying spin-dependent synthetic electric fields to actuate head-on collisions between two BECs of different spin states. We experimentally study and compare the behaviors of the system following SDM excitations in the presence as well as absence of synthetic 1D spin-orbit coupling (SOC). We find that in the absence of SOC, SDM is relatively weakly damped, accompanied with collision-induced thermalization which heats up the atomic cloud. However, in the presence of SOC, we find that SDM is more strongly damped with reduced thermalization, and observe excitation of a quadrupole mode that exhibits BEC shape oscillation even after SDM is damped out. Such a mode conversion bears analogies with the Beliaev coupling process or the parametric frequency down conversion of light in nonlinear optics.

Direct observation and imaging of a spin-wave soliton with p-like symmetry

DOE PAGES

Bonetti, S.; Kukreja, R.; Chen, Z.; ...

2015-11-16

Spin waves, the collective excitations of spins, can emerge as nonlinear solitons at the nanoscale when excited by an electrical current from a nanocontact. These solitons are expected to have essentially cylindrical symmetry (that is, s-like), but no direct experimental observation exists to confirm this picture. Using a high-sensitivity time-resolved magnetic X-ray microscopy with 50 ps temporal resolution and 35 nm spatial resolution, we are able to create a real-space spin-wave movie and observe the emergence of a localized soliton with a nodal line, that is, with p-like symmetry. Moreover, micromagnetic simulations explain the measurements and reveal that the symmetrymore » of the soliton can be controlled by magnetic fields. Our results broaden the understanding of spin-wave dynamics at the nanoscale, with implications for the design of magnetic nanodevices.« less

Influence of the local-spin-density correlation functional on the stability of bcc ferromagnetic iron

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singh, D.; Clougherty, D.P.; MacLaren, J.M.

1991-10-01

The influence of local-spin-dependent correlation effects on the predicted stable ground-state phase of iron is reexamined with use of general-potential linearized augmented-plane-wave calculations. Differences in the form of the Vosko-Wilk-Nusair (VWN) local-spin-density functional used in previous studies are noted, since in previous studies significant additional approximations were made with respect to those of Vosko, Wilk, and Nusan (Can. J. Phys. 58, 1200 (1980)) and of MacLaren, Clougherty, and Albers (Phys. Rev. B 42, 3205 (1990)). While the results of previous linear muffin-tin orbital calculations using the VWN functional predict a bcc ferromagnetic ground state, the present calculations show that themore » VWN spin-correlation effects fail to stabilize a bcc ground state. Considerable sensitivity to the form of the spin interpolation is found.« less

Spin doping using transition metal phthalocyanine molecules

PubMed Central

Atxabal, A.; Ribeiro, M.; Parui, S.; Urreta, L.; Sagasta, E.; Sun, X.; Llopis, R.; Casanova, F.; Hueso, L. E.

2016-01-01

Molecular spins have become key enablers for exploring magnetic interactions, quantum information processes and many-body effects in metals. Metal-organic molecules, in particular, let the spin state of the core metal ion to be modified according to its organic environment, allowing localized magnetic moments to emerge as functional entities with radically different properties from its simple atomic counterparts. Here, using and preserving the integrity of transition metal phthalocyanine high-spin complexes, we demonstrate the magnetic doping of gold thin films, effectively creating a new ground state. We demonstrate it by electrical transport measurements that are sensitive to the scattering of itinerant electrons with magnetic impurities, such as Kondo effect and weak antilocalization. Our work expands in a simple and powerful way the classes of materials that can be used as magnetic dopants, opening a new channel to couple the wide range of molecular properties with spin phenomena at a functional scale. PMID:27941810

Instrumentation for cryogenic magic angle spinning dynamic nuclear polarization using 90 L of liquid nitrogen per day

NASA Astrophysics Data System (ADS)

Albert, Brice J.; Pahng, Seong Ho; Alaniva, Nicholas; Sesti, Erika L.; Rand, Peter W.; Saliba, Edward P.; Scott, Faith J.; Choi, Eric J.; Barnes, Alexander B.

2017-10-01

Cryogenic sample temperatures can enhance NMR sensitivity by extending spin relaxation times to improve dynamic nuclear polarization (DNP) and by increasing Boltzmann spin polarization. We have developed an efficient heat exchanger with a liquid nitrogen consumption rate of only 90 L per day to perform magic-angle spinning (MAS) DNP experiments below 85 K. In this heat exchanger implementation, cold exhaust gas from the NMR probe is returned to the outer portion of a counterflow coil within an intermediate cooling stage to improve cooling efficiency of the spinning and variable temperature gases. The heat exchange within the counterflow coil is calculated with computational fluid dynamics to optimize the heat transfer. Experimental results using the novel counterflow heat exchanger demonstrate MAS DNP signal enhancements of 328 ± 3 at 81 ± 2 K, and 276 ± 4 at 105 ± 2 K.

Conference on the Physics and Chemistry of Semiconductor Interfaces (26th) Held in the Catamaran Resort Hotel in Pacific Beach, San Diego, California on 17 January 1999 to 21 January 1999. Microelectronics and Nanometer Structures: Processing, Measurement, and Phenomena

DTIC Science & Technology

2000-01-27

99)03604-5] I. INTRODUCTION Electron spin is becoming increasingly popular in elec- tronics. New devices, now generally referred to as spintron...relevant spin relaxation mechanisms are very sensitive to factors like mo- bility (which is higher in QWs), electron-hole separation (smaller in...from a naive theory . In addition to explaining experiment, the spin -hot-spot model predicts the behavior of other polyvalent metals. The model is

Note: Spin-exchange optical pumping in a van

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chauvin, C.; Liagre, L.; Boutin, C.

2016-01-15

The advent of spin-hyperpolarization techniques designed to overcome the sensitivity issue of nuclear magnetic resonance owing to polarization transfer from more ordered systems has recently raised great enthusiasm. However, the out-of-equilibrium character of the polarization requires a close proximity between the area of production and the site of use. We present here a mobile spin-exchange optical pumping setup that enables production of laser-polarized noble gases in a standalone mode, in close proximity to hospitals or research laboratories. Only compressed air and mains power need to be supplied by the host laboratory.

Measuring Black Hole Spin

NASA Astrophysics Data System (ADS)

Garmire, Gordon

1999-09-01

WE PROPOSE TO CARRY OUT A SYSTEMATIC STUDY OF EMISSION AND ABSORPTION SPECTRAL FEATURES THAT ARE OFTEN SEEN IN X-RAY SPECTRA OF BLACK HOLE BINARIES. THE EXCELLENT SENSITIVITY AND ENERGY RESOLUTION OF THE ACIS/HETG COMBINATION WILL NOT ONLY HELP RESOLVE AMBIGUITIES IN INTERPRETING THESE FEATURES, BUT MAY ALLOW MODELLING OF THE EMISSION LINE PROFILES IN DETAIL. THE PROFILES MAY CONTAIN INFORMATION ON SUCH FUNDAMENTAL PROPERTIES AS THE SPIN OF BLACK HOLES. THEREFORE, THIS STUDY COULD LEAD TO A MEASUREMENT OF BLACK HOLE SPIN FOR SELECTED SOURCES. THE RESULT CAN THEN BE DIRECTLY COMPARED WITH THOSE FROM PREVIOUS STUDIES BASED ON INDEPENDENT METHODS.

Non-thermal optical excitation of terahertz-spin precession in a magneto-optical insulator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parchenko, Sergii; Maziewski, Andrzej; Stupakiewicz, Andrzej, E-mail: and@uwb.edu.pl

2016-01-18

We demonstrate non-thermal ultrafast laser excitation of spin precession with THz frequency in Gd-Bi-substituted iron garnet via the inverse Faraday effect. The modulation of THz precession by about 60 GHz below the compensation temperature of magnetic moment was observed. The THz frequency precession was caused by the exchange resonance between the Gd and Fe sublattices; we attributed the low-frequency modulation to dielectric resonance mode with a magnetic contribution. We demonstrate the possibility of polarization-sensitive control of spin precession under THz generation by laser pulses, helping to develop high-speed magneto-optical devices.

A novel smart injectable hydrogel prepared by microbial transglutaminase and human-like collagen: Its characterization and biocompatibility.

PubMed

Zhao, Leilei; Li, Xian; Zhao, Jiaqi; Ma, Saijian; Ma, Xiaoxuan; Fan, Daidi; Zhu, Chenhui; Liu, Yannan

2016-11-01

Various tissue scaffold materials are increasingly used to repair skin defects by cross-linking because of the ability to fill and implant in any form via operation. However, crosslinker residues cannot be easily removed from scaffold materials prepared by chemical crosslinking methods, limiting their use for skin tissue engineering. Here, microbial transglutaminase (MTGase), a nontoxic crosslinker with high specific activity and reaction rate under mild conditions, was employed crosslinks in human-like collagen (HLC) to yield novel smart MTGase crosslinked with human-like collagen (MTGH) hydrogels, which are sensitive to temperature and/or enzymes. Various ratios of MTGase/HLC were performed, and their physicochemical properties were characterized, including the swelling ratio, the elastic modulus, the morphology and the porosity. The degradation behavior and mechanism of MTGase in concentration-dependent manner involved in formation hydrogels were identifying in vitro. The cell attachment in vitro and biocompatibility in vivo were also investigated. The results demonstrated that the use of different concentrations of MTGase to crosslink HLC produced products with different degradation times and biocompatibilities. The 50U/g MTGase-prepared MTGH hydrogels had a higher density of crosslinks, which made them more resistant to degradation by collagenase I and collagenase II. However, 40U/g MTGase-prepared MTGH hydrogels were more suitable for cell attachment. In addition, compared with the Collagen Implant I® (SUM) used in animal experiments, the 40U/g MTGase-prepared MTGH hydrogels had a lower toxicity and better biocompatibility. Therefore, 40U/g MTGase crosslinked with HLC should be used to prepare MTGH hydrogels for potential application as soft materials for skin tissue engineering. Copyright © 2016 Elsevier B.V. All rights reserved.

Demonstration of a Sensitive Method to Measure Nuclear-Spin-Dependent Parity Violation

NASA Astrophysics Data System (ADS)

Altuntaş, Emine; Ammon, Jeffrey; Cahn, Sidney B.; DeMille, David

2018-04-01

Nuclear-spin-dependent parity violation (NSD-PV) effects in atoms and molecules arise from Z0 boson exchange between electrons and the nucleus, and from the magnetic interaction between electrons and the parity-violating nuclear anapole moment. We demonstrate measurements of NSD-PV that use an enhancement of the effect in diatomic molecules, here using the test system 138Ba 19. Our sensitivity surpasses that of any previous atomic parity violation measurement. We show that systematic errors can be suppressed to at least the level of the present statistical sensitivity. We measure the matrix element W of the NSD-PV interaction with total uncertainty δ W /(2 π )<0.7 Hz , for each of two configurations where W must have different signs. This sensitivity would be sufficient to measure NSD-PV effects of the size anticipated across a wide range of nuclei including 137Ba in 137BaF, where |W |/(2 π )≈5 Hz is expected.

First measurement of the vector analyzing power in muon capture by polarized muonic {sup 3}He

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cummings, W.J.; Behr, J.; Bogorad, P.

1995-09-01

This paper describes the first measurement of spin observables in nuclear muon capture by {sup 3}He. The sensitivity of spin observables to the pseudoscalar coupling is described. The triton asymmetry presented has to be corrected for small systematic effects in order to extract the vector analyzing power. The analysis of these effects is currently underway.

Low-cost high-resolution fast spin-echo MR of acoustic schwannoma: an alternative to enhanced conventional spin-echo MR?

PubMed

Allen, R W; Harnsberger, H R; Shelton, C; King, B; Bell, D A; Miller, R; Parkin, J L; Apfelbaum, R I; Parker, D

1996-08-01

To determine whether unenhanced high-resolution T2-weighted fast spin-echo MR imaging provides an acceptable and less expensive alternative to contrast-enhanced conventional T1-weighted spin-echo MR techniques in the diagnosis of acoustic schwannoma. We reviewed in a blinded fashion the records of 25 patients with pathologically documented acoustic schwannoma and of 25 control subjects, all of whom had undergone both enhanced conventional spin-echo MR imaging and unenhanced fast spin-echo MR imaging of the cerebellopontine angle/internal auditory canal region. The patients were imaged with the use of a quadrature head receiver coil for the conventional spin-echo sequences and dual 3-inch phased-array receiver coils for the fast spin-echo sequences. The size of the acoustic schwannomas ranged from 2 to 40 mm in maximum dimension. The mean maximum diameter was 12 mm, and 12 neoplasms were less than 10 mm in diameter. Acoustic schwannoma was correctly diagnosed on 98% of the fast spin-echo images and on 100% of the enhanced conventional spin-echo images. Statistical analysis of the data using the kappa coefficient demonstrated agreement beyond chance between these two imaging techniques for the diagnosis of acoustic schwannoma. There is no statistically significant difference in the sensitivity and specificity of unenhanced high-resolution fast spin-echo imaging and enhance T1-weighted conventional spin-echo imaging in the detection of acoustic schwannoma. We believe that the unenhanced high-resolution fast spin-echo technique provides a cost-effective method for the diagnosis of acoustic schwannoma.

A spin echo sequence with a single-sided bipolar diffusion gradient pulse to obtain snapshot diffusion weighted images in moving media

NASA Astrophysics Data System (ADS)

Freidlin, R. Z.; Kakareka, J. W.; Pohida, T. J.; Komlosh, M. E.; Basser, P. J.

2012-08-01

In vivo MRI data can be corrupted by motion. Motion artifacts are particularly troublesome in Diffusion Weighted MRI (DWI), since the MR signal attenuation due to Brownian motion can be much less than the signal loss due to dephasing from other types of complex tissue motion, which can significantly degrade the estimation of self-diffusion coefficients, diffusion tensors, etc. This paper describes a snapshot DWI sequence, which utilizes a novel single-sided bipolar diffusion sensitizing gradient pulse within a spin echo sequence. The proposed method shortens the diffusion time by applying a single refocused bipolar diffusion gradient on one side of a refocusing RF pulse, instead of a set of diffusion sensitizing gradients, separated by a refocusing RF pulse, while reducing the impact of magnetic field inhomogeneity by using a spin echo sequence. A novel MRI phantom that can exhibit a range of complex motions was designed to demonstrate the robustness of the proposed DWI sequence.

Weak-field precession of nano-pillar spin-torque oscillators using MgO-based perpendicular magnetic tunnel junction

NASA Astrophysics Data System (ADS)

Zhang, Changxin; Fang, Bin; Wang, Bochong; Zeng, Zhongming

2018-04-01

This paper presents a steady auto-oscillation in a spin-torque oscillator using MgO-based magnetic tunnel junction (MTJ) with a perpendicular polarizer and a perpendicular free layer. As the injected d.c. current varied from 1.5 to 3.0 mA under a weak magnetic field of 290 Oe, the oscillation frequency decreased from 1.85 to 1.3 GHz, and the integrated power increased from 0.1 to 74 pW. A narrow linewidth down to 7 MHz corresponding to a high Q factor of 220 was achieved at 2.7 mA, which was ascribed to the spatial coherent procession of the free layer magnetization. Moreover, the oscillation frequency was quite sensitive to the applied field, about 3.07 MHz/Oe, indicating the potential applications as a weak magnetic field detector. These results suggested that the MgO-based MTJ with perpendicular magnetic easy axis could be helpful for developing spin-torque oscillators with narrow-linewidth and high sensitive.

Comparison of axial T1 spin-echo and T1 fat-saturation magnetic resonance imaging techniques in the diagnosis of chondromalacia patellae.

PubMed

Vanarthos, W J; Pope, T L; Monu, J U

1994-12-01

To test the diagnostic value of T1 spin-echo and T1 fat-saturated magnetic resonance images (MRIs), we reviewed axial T1-weighted images with and without fat saturation in 20 patients with clinically suspected chondromalacia of the patella. All scans were obtained on 1.5-MR units. The scans were randomly ordered and reviewed independently at different times by two radiologists without knowledge of the arthroscopy results. The sensitivity of the individual techniques for detecting grade 3 or 4 chondromalacia patellae was 92% for fat-saturated axial T1-weighted images alone, and 67% for axial T1-weighted images without fat saturation. The sensitivity of the combined techniques was 100% for grades 3 and 4 and 90% for all grades (0 to 4). Chondromalacia patellae is diagnosed more accurately by using T1 fat saturation than by using T1 spin-echo images. With a combination of the two techniques, accuracy is 90% to 100%.

Non-local detection of spin dynamics via spin rectification effect in yttrium iron garnet/SiO{sub 2}/NiFe trilayers near simultaneous ferromagnetic resonance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Soh, Wee Tee, E-mail: a0046479@u.nus.edu; Ong, C. K.; Peng, Bin

2015-08-15

The spin rectification effect (SRE), a phenomenon that generates dc voltages from ac microwave fields incident onto a conducting ferromagnet, has attracted widespread attention due to its high sensitivity to ferromagnetic resonance (FMR) as well as its relevance to spintronics. Here, we report the non-local detection of yttrium iron garnet (YIG) spin dynamics by measuring SRE voltages from an adjacent conducting NiFe layer up to 200 nm thick. In particular, we detect, within the NiFe layer, SRE voltages stemming from magnetostatic surface spin waves (MSSWs) of the adjacent bulk YIG which are excited by a shorted coaxial probe. These non-localmore » SRE voltages within the NiFe layer that originates from YIG MSSWs are present even in 200 nm-thick NiFe films with a 50 nm thick SiO{sub 2} spacer between NiFe and YIG, thus strongly ruling out the mechanism of spin-pumping induced inverse spin Hall effect in NiFe as the source of these voltages. This long-range influence of YIG dynamics is suggested to be mediated by dynamic fields generated from YIG spin precession near YIG/NiFe interface, which interacts with NiFe spins near the simultaneous resonance of both spins, to generate a non-local SRE voltage within the NiFe layer.« less

Glucose response of near-infrared alginate-based microsphere sensors under dynamic reversible conditions.

PubMed

Chaudhary, Ayesha; Harma, Harri; Hanninen, Pekka; McShane, Michael J; Srivastava, Rohit

2011-08-01

Minimally invasive optical glucose biosensors with increased functional longevity form one of the most promising techniques for continuous glucose monitoring, because of their long-term stability, reversibility, repeatability, specificity, and high sensitivity. They are based on the principle of competitive binding and fluorescence resonance energy transfer. Moving to the near-infrared region of the spectrum has the potential to improve signal throughput for implanted sensors, but requires a change in dye chemistry that could alter response sensitivity, range, and toxicity profiles. The near-infrared dissolved-core alginate microsphere sensors were fabricated by emulsion followed by surface coating by layer-by-layer self-assembly. The particles were characterized for sensor stability, sensor response, and reversibility in deionized water and simulated interstitial fluid. The sensor response to step changes in bulk glucose concentrations was also evaluated under dynamic conditions using a microflow cell unit. Finally, in vitro cytotoxicity assays were performed with L929 mouse fibroblast cell lines to demonstrate preliminary biocompatibility of the sensors. The glucose sensitivity under controlled and dynamic conditions was observed to be 0.86%/mM glucose with an analytical response range of 0-30 mM glucose, covering both the physiological and pathophysiological range. The sensor demonstrated a repeatable, reversible, and reproducible response, with a maximum response time of 120 s. In vitro cytotoxicity assays revealed nearly 95% viability of cells, thereby suggesting that the alginate microsphere sensor system does not exhibit cytotoxicity. The incorporation of near-infrared dyes shows promise in improving sensor response because of their high sensitivity and improved tissue penetration of infrared light. The sensitivity for the sensors was approximately 1.5 times greater than that observed for visible dye sensors, and the new dye chemistry did not significantly alter the biocompatibility of the materials. These findings provide additional support for the potential application of alginate microspheres and similar systems such as "smart-tattoo" glucose sensors.

Muon Spin Relaxation/Rotation Studies of Novel Magnetic Systems

NASA Astrophysics Data System (ADS)

Luke, Graeme

Muon spin relaxation/rotation is a powerful technique for probing magnetism in materials. As a real space probe, the muon complements neutron scattering's reciprocal space sensitivity. Muons probe magnetic fluctuations in a frequency window between inelastic neutron scattering and nuclear magnetic resonance. In this presentation I will describe our recent work on geometrically frustrated materials including the pyrochlore lattice compounds Yb2Ti

High-resolution magnetic resonance spectroscopy using a solid-state spin sensor

NASA Astrophysics Data System (ADS)

Glenn, David R.; Bucher, Dominik B.; Lee, Junghyun; Lukin, Mikhail D.; Park, Hongkun; Walsworth, Ronald L.

2018-03-01

Quantum systems that consist of solid-state electronic spins can be sensitive detectors of nuclear magnetic resonance (NMR) signals, particularly from very small samples. For example, nitrogen–vacancy centres in diamond have been used to record NMR signals from nanometre-scale samples, with sensitivity sufficient to detect the magnetic field produced by a single protein. However, the best reported spectral resolution for NMR of molecules using nitrogen–vacancy centres is about 100 hertz. This is insufficient to resolve the key spectral identifiers of molecular structure that are critical to NMR applications in chemistry, structural biology and materials research, such as scalar couplings (which require a resolution of less than ten hertz) and small chemical shifts (which require a resolution of around one part per million of the nuclear Larmor frequency). Conventional, inductively detected NMR can provide the necessary high spectral resolution, but its limited sensitivity typically requires millimetre-scale samples, precluding applications that involve smaller samples, such as picolitre-volume chemical analysis or correlated optical and NMR microscopy. Here we demonstrate a measurement technique that uses a solid-state spin sensor (a magnetometer) consisting of an ensemble of nitrogen–vacancy centres in combination with a narrowband synchronized readout protocol to obtain NMR spectral resolution of about one hertz. We use this technique to observe NMR scalar couplings in a micrometre-scale sample volume of approximately ten picolitres. We also use the ensemble of nitrogen–vacancy centres to apply NMR to thermally polarized nuclear spins and resolve chemical-shift spectra from small molecules. Our technique enables analytical NMR spectroscopy at the scale of single cells.

Direct Measurement of the Flip-Flop Rate of Electron Spins in the Solid State

NASA Astrophysics Data System (ADS)

Dikarov, Ekaterina; Zgadzai, Oleg; Artzi, Yaron; Blank, Aharon

2016-10-01

Electron spins in solids have a central role in many current and future spin-based devices, ranging from sensitive sensors to quantum computers. Many of these apparatuses rely on the formation of well-defined spin structures (e.g., a 2D array) with controlled and well-characterized spin-spin interactions. While being essential for device operation, these interactions can also result in undesirable effects, such as decoherence. Arguably, the most important pure quantum interaction that causes decoherence is known as the "flip-flop" process, where two interacting spins interchange their quantum state. Currently, for electron spins, the rate of this process can only be estimated theoretically, or measured indirectly, under limiting assumptions and approximations, via spin-relaxation data. This work experimentally demonstrates how the flip-flop rate can be directly and accurately measured by examining spin-diffusion processes in the solid state for physically fixed spins. Under such terms, diffusion can occur only through this flip-flop-mediated quantum-state exchange and not via actual spatial motion. Our approach is implemented on two types of samples, phosphorus-doped 28Si and nitrogen vacancies in diamond, both of which are significantly relevant to quantum sensors and information processing. However, while the results for the former sample are conclusive and reveal a flip-flop rate of approximately 12.3 Hz, for the latter sample only an upper limit of approximately 0.2 Hz for this rate can be estimated.

Quantized spin-momentum transfer in atom-sized magnetic systems

NASA Astrophysics Data System (ADS)

Loth, Sebastian

2010-03-01

Our ability to quickly access the vast amounts of information linked in the internet is owed to the miniaturization of magnetic data storage. In modern disk drives the tunnel magnetoresistance effect (TMR) serves as sensitive reading mechanism for the nanoscopic magnetic bits [1]. At its core lies the ability to control the flow of electrons with a material's magnetization. The inverse effect, spin transfer torque (STT), allows one to influence a magnetic layer by high current densities of spin-polarized electrons and carries high hopes for applications in non-volatile magnetic memory [2]. We show that equivalent processes are active in quantum spin systems. We use a scanning tunneling microscope (STM) operating at low temperature and high magnetic field to address individual magnetic structures and probe their spin excitations by inelastic electron tunneling [3]. As model system we investigate transition metal atoms adsorbed to a copper nitride layer grown on a Cu crystal. The magnetic atoms on the surface possess well-defined spin states [4]. Transfer of one magnetic atom to the STM tip's apex creates spin-polarization in the probe tip. The combination of functionalized tip and surface adsorbed atom resembles a TMR structure where the magnetic layers now consist of one magnetic atom each. Spin-polarized current emitted from the probe tip not only senses the magnetic orientation of the atomic spin system, it efficiently transfers spin angular momentum and pumps the quantum spin system between the different spin states. This enables further exploration of the microscopic mechanisms for spin-relaxation and stability of quantum spin systems. [4pt] [1] Zhu and Park, Mater. Today 9, 36 (2006).[0pt] [2] Huai, AAPPS Bulletin 18, 33 (2008).[0pt] [3] Heinrich et al., Science 306, 466 (2004).[0pt] [4] Hirjibehedin et al., Science 317, 1199 (2007).

Robust techniques for polarization and detection of nuclear spin ensembles

NASA Astrophysics Data System (ADS)

Scheuer, Jochen; Schwartz, Ilai; Müller, Samuel; Chen, Qiong; Dhand, Ish; Plenio, Martin B.; Naydenov, Boris; Jelezko, Fedor

2017-11-01

Highly sensitive nuclear spin detection is crucial in many scientific areas including nuclear magnetic resonance spectroscopy, magnetic resonance imaging (MRI), and quantum computing. The tiny thermal nuclear spin polarization represents a major obstacle towards this goal which may be overcome by dynamic nuclear spin polarization (DNP) methods. The latter often rely on the transfer of the thermally polarized electron spins to nearby nuclear spins, which is limited by the Boltzmann distribution of the former. Here we utilize microwave dressed states to transfer the high (>92 % ) nonequilibrium electron spin polarization of a single nitrogen-vacancy center (NV) induced by short laser pulses to the surrounding 13C carbon nuclear spins. The NV is repeatedly repolarized optically, thus providing an effectively infinite polarization reservoir. A saturation of the polarization of the nearby nuclear spins is achieved, which is confirmed by the decay of the polarization transfer signal and shows an excellent agreement with theoretical simulations. Hereby we introduce the polarization readout by polarization inversion method as a quantitative magnetization measure of the nuclear spin bath, which allows us to observe by ensemble averaging macroscopically hidden polarization dynamics like Landau-Zener-Stückelberg oscillations. Moreover, we show that using the integrated solid effect both for single- and double-quantum transitions nuclear spin polarization can be achieved even when the static magnetic field is not aligned along the NV's crystal axis. This opens a path for the application of our DNP technique to spins in and outside of nanodiamonds, enabling their application as MRI tracers. Furthermore, the methods reported here can be applied to other solid state systems where a central electron spin is coupled to a nuclear spin bath, e.g., phosphor donors in silicon and color centers in silicon carbide.

First narrow-band search for continuous gravitational waves from known pulsars in advanced detector data

NASA Astrophysics Data System (ADS)

Abbott, B. P.; Abbott, R.; Abbott, T. D.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Addesso, P.; Adhikari, R. X.; Adya, V. B.; Affeldt, C.; Afrough, M.; Agarwal, B.; Agathos, M.; Agatsuma, K.; Aggarwal, N.; Aguiar, O. D.; Aiello, L.; Ain, A.; Allen, B.; Allen, G.; Allocca, A.; Altin, P. A.; Amato, A.; Ananyeva, A.; Anderson, S. B.; Anderson, W. G.; Angelova, S. V.; Antier, S.; Appert, S.; Arai, K.; Araya, M. C.; Areeda, J. S.; Arnaud, N.; Arun, K. G.; Ascenzi, S.; Ashton, G.; Ast, M.; Aston, S. M.; Astone, P.; Atallah, D. V.; Aufmuth, P.; Aulbert, C.; AultONeal, K.; Austin, C.; Avila-Alvarez, A.; Babak, S.; Bacon, P.; Bader, M. K. M.; Bae, S.; Baker, P. T.; Baldaccini, F.; Ballardin, G.; Ballmer, S. W.; Banagiri, S.; Barayoga, J. C.; Barclay, S. E.; Barish, B. C.; Barker, D.; Barkett, K.; Barone, F.; Barr, B.; Barsotti, L.; Barsuglia, M.; Barta, D.; Bartlett, J.; Bartos, I.; Bassiri, R.; Basti, A.; Batch, J. C.; Bawaj, M.; Bayley, J. C.; Bazzan, M.; Bécsy, B.; Beer, C.; Bejger, M.; Belahcene, I.; Bell, A. S.; Berger, B. K.; Bergmann, G.; Bero, J. J.; Berry, C. P. L.; Bersanetti, D.; Bertolini, A.; Betzwieser, J.; Bhagwat, S.; Bhandare, R.; Bilenko, I. A.; Billingsley, G.; Billman, C. R.; Birch, J.; Birney, R.; Birnholtz, O.; Biscans, S.; Biscoveanu, S.; Bisht, A.; Bitossi, M.; Biwer, C.; Bizouard, M. A.; Blackburn, J. K.; Blackman, J.; Blair, C. D.; Blair, D. G.; Blair, R. M.; Bloemen, S.; Bock, O.; Bode, N.; Boer, M.; Bogaert, G.; Bohe, A.; Bondu, F.; Bonilla, E.; Bonnand, R.; Boom, B. A.; Bork, R.; Boschi, V.; Bose, S.; Bossie, K.; Bouffanais, Y.; Bozzi, A.; Bradaschia, C.; Brady, P. R.; Branchesi, M.; Brau, J. E.; Briant, T.; Brillet, A.; Brinkmann, M.; Brisson, V.; Brockill, P.; Broida, J. E.; Brooks, A. F.; Brown, D. A.; Brown, D. D.; Brunett, S.; Buchanan, C. C.; Buikema, A.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Buskulic, D.; Buy, C.; Byer, R. L.; Cabero, M.; Cadonati, L.; Cagnoli, G.; Cahillane, C.; Calderón Bustillo, J.; Callister, T. A.; Calloni, E.; Camp, J. B.; Canizares, P.; Cannon, K. C.; Cao, H.; Cao, J.; Capano, C. D.; Capocasa, E.; Carbognani, F.; Caride, S.; Carney, M. F.; Casanueva Diaz, J.; Casentini, C.; Caudill, S.; Cavaglià, M.; Cavalier, F.; Cavalieri, R.; Cella, G.; Cepeda, C. B.; Cerdá-Durán, P.; Cerretani, G.; Cesarini, E.; Chamberlin, S. J.; Chan, M.; Chao, S.; Charlton, P.; Chase, E.; Chassande-Mottin, E.; Chatterjee, D.; Cheeseboro, B. D.; Chen, H. Y.; Chen, X.; Chen, Y.; Cheng, H.-P.; Chia, H.; Chincarini, A.; Chiummo, A.; Chmiel, T.; Cho, H. S.; Cho, M.; Chow, J. H.; Christensen, N.; Chu, Q.; Chua, A. J. K.; Chua, S.; Chung, A. K. W.; Chung, S.; Ciani, G.; Ciolfi, R.; Cirelli, C. E.; Cirone, A.; Clara, F.; Clark, J. A.; Clearwater, P.; Cleva, F.; Cocchieri, C.; Coccia, E.; Cohadon, P.-F.; Cohen, D.; Colla, A.; Collette, C. G.; Cominsky, L. R.; Constancio, M.; Conti, L.; Cooper, S. J.; Corban, P.; Corbitt, T. R.; Cordero-Carrión, I.; Corley, K. R.; Cornish, N.; Corsi, A.; Cortese, S.; Costa, C. A.; Coughlin, M. W.; Coughlin, S. B.; Coulon, J.-P.; Countryman, S. T.; Couvares, P.; Covas, P. B.; Cowan, E. E.; Coward, D. M.; Cowart, M. J.; Coyne, D. C.; Coyne, R.; Creighton, J. D. E.; Creighton, T. D.; Cripe, J.; Crowder, S. G.; Cullen, T. J.; Cumming, A.; Cunningham, L.; Cuoco, E.; Dal Canton, T.; Dálya, G.; Danilishin, S. L.; D'Antonio, S.; Danzmann, K.; Dasgupta, A.; Da Silva Costa, C. F.; Dattilo, V.; Dave, I.; Davier, M.; Davis, D.; Daw, E. J.; Day, B.; De, S.; DeBra, D.; Degallaix, J.; De Laurentis, M.; Deléglise, S.; Del Pozzo, W.; Demos, N.; Denker, T.; Dent, T.; De Pietri, R.; Dergachev, V.; De Rosa, R.; DeRosa, R. T.; De Rossi, C.; DeSalvo, R.; de Varona, O.; Devenson, J.; Dhurandhar, S.; Díaz, M. C.; Di Fiore, L.; Di Giovanni, M.; Di Girolamo, T.; Di Lieto, A.; Di Pace, S.; Di Palma, I.; Di Renzo, F.; Doctor, Z.; Dolique, V.; Donovan, F.; Dooley, K. L.; Doravari, S.; Dorrington, I.; Douglas, R.; Dovale Álvarez, M.; Downes, T. P.; Drago, M.; Dreissigacker, C.; Driggers, J. C.; Du, Z.; Ducrot, M.; Dupej, P.; Dwyer, S. E.; Edo, T. B.; Edwards, M. C.; Effler, A.; Eggenstein, H.-B.; Ehrens, P.; Eichholz, J.; Eikenberry, S. S.; Eisenstein, R. A.; Essick, R. C.; Estevez, D.; Etienne, Z. B.; Etzel, T.; Evans, M.; Evans, T. M.; Factourovich, M.; Fafone, V.; Fair, H.; Fairhurst, S.; Fan, X.; Farinon, S.; Farr, B.; Farr, W. M.; Fauchon-Jones, E. J.; Favata, M.; Fays, M.; Fee, C.; Fehrmann, H.; Feicht, J.; Fejer, M. M.; Fernandez-Galiana, A.; Ferrante, I.; Ferreira, E. C.; Ferrini, F.; Fidecaro, F.; Finstad, D.; Fiori, I.; Fiorucci, D.; Fishbach, M.; Fisher, R. P.; Fitz-Axen, M.; Flaminio, R.; Fletcher, M.; Fong, H.; Font, J. A.; Forsyth, P. W. F.; Forsyth, S. S.; Fournier, J.-D.; Frasca, S.; Frasconi, F.; Frei, Z.; Freise, A.; Frey, R.; Frey, V.; Fries, E. M.; Fritschel, P.; Frolov, V. V.; Fulda, P.; Fyffe, M.; Gabbard, H.; Gadre, B. U.; Gaebel, S. M.; Gair, J. R.; Gammaitoni, L.; Ganija, M. R.; Gaonkar, S. G.; Garcia-Quiros, C.; Garufi, F.; Gateley, B.; Gaudio, S.; Gaur, G.; Gayathri, V.; Gehrels, N.; Gemme, G.; Genin, E.; Gennai, A.; George, D.; George, J.; Gergely, L.; Germain, V.; Ghonge, S.; Ghosh, Abhirup; Ghosh, Archisman; Ghosh, S.; Giaime, J. A.; Giardina, K. D.; Giazotto, A.; Gill, K.; Glover, L.; Goetz, E.; Goetz, R.; Gomes, S.; Goncharov, B.; González, G.; Gonzalez Castro, J. M.; Gopakumar, A.; Gorodetsky, M. L.; Gossan, S. E.; Gosselin, M.; Gouaty, R.; Grado, A.; Graef, C.; Granata, M.; Grant, A.; Gras, S.; Gray, C.; Greco, G.; Green, A. C.; Gretarsson, E. M.; Groot, P.; Grote, H.; Grunewald, S.; Gruning, P.; Guidi, G. M.; Guo, X.; Gupta, A.; Gupta, M. K.; Gushwa, K. E.; Gustafson, E. K.; Gustafson, R.; Halim, O.; Hall, B. R.; Hall, E. D.; Hamilton, E. Z.; Hammond, G.; Haney, M.; Hanke, M. M.; Hanks, J.; Hanna, C.; Hannam, M. D.; Hannuksela, O. A.; Hanson, J.; Hardwick, T.; Harms, J.; Harry, G. M.; Harry, I. W.; Hart, M. J.; Haster, C.-J.; Haughian, K.; Healy, J.; Heidmann, A.; Heintze, M. C.; Heitmann, H.; Hello, P.; Hemming, G.; Hendry, M.; Heng, I. S.; Hennig, J.; Heptonstall, A. W.; Heurs, M.; Hild, S.; Hinderer, T.; Ho, W. C. G.; Hoak, D.; Hofman, D.; Holt, K.; Holz, D. E.; Hopkins, P.; Horst, C.; Hough, J.; Houston, E. A.; Howell, E. J.; Hreibi, A.; Hu, Y. M.; Huerta, E. A.; Huet, D.; Hughey, B.; Husa, S.; Huttner, S. H.; Huynh-Dinh, T.; Indik, N.; Inta, R.; Intini, G.; Isa, H. N.; Isac, J.-M.; Isi, M.; Iyer, B. R.; Izumi, K.; Jacqmin, T.; Jani, K.; Jaranowski, P.; Jawahar, S.; Jiménez-Forteza, F.; Johnson, W. W.; Jones, D. I.; Jones, R.; Jonker, R. J. G.; Ju, L.; Junker, J.; Kalaghatgi, C. V.; Kalogera, V.; Kamai, B.; Kandhasamy, S.; Kang, G.; Kanner, J. B.; Kapadia, S. J.; Karki, S.; Karvinen, K. S.; Kasprzack, M.; Katolik, M.; Katsavounidis, E.; Katzman, W.; Kaufer, S.; Kawabe, K.; Kéfélian, F.; Keitel, D.; Kemball, A. J.; Kennedy, R.; Kent, C.; Key, J. S.; Khalili, F. Y.; Khan, I.; Khan, S.; Khan, Z.; Khazanov, E. A.; Kijbunchoo, N.; Kim, Chunglee; Kim, J. C.; Kim, K.; Kim, W.; Kim, W. S.; Kim, Y.-M.; Kimbrell, S. J.; King, E. J.; King, P. J.; Kinley-Hanlon, M.; Kirchhoff, R.; Kissel, J. S.; Kleybolte, L.; Klimenko, S.; Knowles, T. D.; Koch, P.; Koehlenbeck, S. M.; Koley, S.; Kondrashov, V.; Kontos, A.; Korobko, M.; Korth, W. Z.; Kowalska, I.; Kozak, D. B.; Krämer, C.; Kringel, V.; Krishnan, B.; Królak, A.; Kuehn, G.; Kumar, P.; Kumar, R.; Kumar, S.; Kuo, L.; Kutynia, A.; Kwang, S.; Lackey, B. D.; Lai, K. H.; Landry, M.; Lang, R. N.; Lange, J.; Lantz, B.; Lanza, R. K.; Lartaux-Vollard, A.; Lasky, P. D.; Laxen, M.; Lazzarini, A.; Lazzaro, C.; Leaci, P.; Leavey, S.; Lee, C. H.; Lee, H. K.; Lee, H. M.; Lee, H. W.; Lee, K.; Lehmann, J.; Lenon, A.; Leonardi, M.; Leroy, N.; Letendre, N.; Levin, Y.; Li, T. G. F.; Linker, S. D.; Littenberg, T. B.; Liu, J.; Lo, R. K. L.; Lockerbie, N. A.; London, L. T.; Lord, J. E.; Lorenzini, M.; Loriette, V.; Lormand, M.; Losurdo, G.; Lough, J. D.; Lovelace, G.; Lück, H.; Lumaca, D.; Lundgren, A. P.; Lynch, R.; Ma, Y.; Macas, R.; Macfoy, S.; Machenschalk, B.; MacInnis, M.; Macleod, D. M.; Magaña Hernandez, I.; Magaña-Sandoval, F.; Magaña Zertuche, L.; Magee, R. M.; Majorana, E.; Maksimovic, I.; Man, N.; Mandic, V.; Mangano, V.; Mansell, G. L.; Manske, M.; Mantovani, M.; Marchesoni, F.; Marion, F.; Márka, S.; Márka, Z.; Markakis, C.; Markosyan, A. S.; Markowitz, A.; Maros, E.; Marquina, A.; Martelli, F.; Martellini, L.; Martin, I. W.; Martin, R. M.; Martynov, D. V.; Mason, K.; Massera, E.; Masserot, A.; Massinger, T. J.; Masso-Reid, M.; Mastrogiovanni, S.; Matas, A.; Matichard, F.; Matone, L.; Mavalvala, N.; Mazumder, N.; McCarthy, R.; McClelland, D. E.; McCormick, S.; McCuller, L.; McGuire, S. C.; McIntyre, G.; McIver, J.; McManus, D. J.; McNeill, L.; McRae, T.; McWilliams, S. T.; Meacher, D.; Meadors, G. D.; Mehmet, M.; Meidam, J.; Mejuto-Villa, E.; Melatos, A.; Mendell, G.; Mercer, R. A.; Merilh, E. L.; Merzougui, M.; Meshkov, S.; Messenger, C.; Messick, C.; Metzdorff, R.; Meyers, P. M.; Miao, H.; Michel, C.; Middleton, H.; Mikhailov, E. E.; Milano, L.; Miller, A. L.; Miller, B. B.; Miller, J.; Millhouse, M.; Milovich-Goff, M. C.; Minazzoli, O.; Minenkov, Y.; Ming, J.; Mishra, C.; Mitra, S.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Moffa, D.; Moggi, A.; Mogushi, K.; Mohan, M.; Mohapatra, S. R. P.; Montani, M.; Moore, C. J.; Moraru, D.; Moreno, G.; Morriss, S. R.; Mours, B.; Mow-Lowry, C. M.; Mueller, G.; Muir, A. W.; Mukherjee, Arunava; Mukherjee, D.; Mukherjee, S.; Mukund, N.; Mullavey, A.; Munch, J.; Muñiz, E. A.; Muratore, M.; Murray, P. G.; Napier, K.; Nardecchia, I.; Naticchioni, L.; Nayak, R. K.; Neilson, J.; Nelemans, G.; Nelson, T. J. N.; Nery, M.; Neunzert, A.; Nevin, L.; Newport, J. M.; Newton, G.; Ng, K. K. Y.; Nguyen, T. T.; Nichols, D.; Nielsen, A. B.; Nissanke, S.; Nitz, A.; Noack, A.; Nocera, F.; Nolting, D.; North, C.; Nuttall, L. K.; Oberling, J.; O'Dea, G. D.; Ogin, G. H.; Oh, J. J.; Oh, S. H.; Ohme, F.; Okada, M. A.; Oliver, M.; Oppermann, P.; Oram, Richard J.; O'Reilly, B.; Ormiston, R.; Ortega, L. F.; O'Shaughnessy, R.; Ossokine, S.; Ottaway, D. J.; Overmier, H.; Owen, B. J.; Pace, A. E.; Page, J.; Page, M. A.; Pai, A.; Pai, S. A.; Palamos, J. R.; Palashov, O.; Palomba, C.; Pal-Singh, A.; Pan, Howard; Pan, Huang-Wei; Pang, B.; Pang, P. T. H.; Pankow, C.; Pannarale, F.; Pant, B. C.; Paoletti, F.; Paoli, A.; Papa, M. A.; Parida, A.; Parker, W.; Pascucci, D.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Patil, M.; Patricelli, B.; Pearlstone, B. L.; Pedraza, M.; Pedurand, R.; Pekowsky, L.; Pele, A.; Penn, S.; Perez, C. J.; Perreca, A.; Perri, L. M.; Pfeiffer, H. P.; Phelps, M.; Piccinni, O. J.; Pichot, M.; Piergiovanni, F.; Pierro, V.; Pillant, G.; Pinard, L.; Pinto, I. M.; Pirello, M.; Pitkin, M.; Poe, M.; Poggiani, R.; Popolizio, P.; Porter, E. K.; Post, A.; Powell, J.; Prasad, J.; Pratt, J. W. W.; Pratten, G.; Predoi, V.; Prestegard, T.; Prijatelj, M.; Principe, M.; Privitera, S.; Prodi, G. A.; Prokhorov, L. G.; Puncken, O.; Punturo, M.; Puppo, P.; Pürrer, M.; Qi, H.; Quetschke, V.; Quintero, E. A.; Quitzow-James, R.; Raab, F. J.; Rabeling, D. S.; Radkins, H.; Raffai, P.; Raja, S.; Rajan, C.; Rajbhandari, B.; Rakhmanov, M.; Ramirez, K. E.; Ramos-Buades, A.; Rapagnani, P.; Raymond, V.; Razzano, M.; Read, J.; Regimbau, T.; Rei, L.; Reid, S.; Reitze, D. H.; Ren, W.; Reyes, S. D.; Ricci, F.; Ricker, P. M.; Rieger, S.; Riles, K.; Rizzo, M.; Robertson, N. A.; Robie, R.; Robinet, F.; Rocchi, A.; Rolland, L.; Rollins, J. G.; Roma, V. J.; Romano, R.; Romel, C. L.; Romie, J. H.; Rosińska, D.; Ross, M. P.; Rowan, S.; Rüdiger, A.; Ruggi, P.; Rutins, G.; Ryan, K.; Sachdev, S.; Sadecki, T.; Sadeghian, L.; Sakellariadou, M.; Salconi, L.; Saleem, M.; Salemi, F.; Samajdar, A.; Sammut, L.; Sampson, L. M.; Sanchez, E. J.; Sanchez, L. E.; Sanchis-Gual, N.; Sandberg, V.; Sanders, J. R.; Sassolas, B.; Sathyaprakash, B. S.; Saulson, P. R.; Sauter, O.; Savage, R. L.; Sawadsky, A.; Schale, P.; Scheel, M.; Scheuer, J.; Schmidt, J.; Schmidt, P.; Schnabel, R.; Schofield, R. M. S.; Schönbeck, A.; Schreiber, E.; Schuette, D.; Schulte, B. W.; Schutz, B. F.; Schwalbe, S. G.; Scott, J.; Scott, S. M.; Seidel, E.; Sellers, D.; Sengupta, A. S.; Sentenac, D.; Sequino, V.; Sergeev, A.; Shaddock, D. A.; Shaffer, T. J.; Shah, A. A.; Shahriar, M. S.; Shaner, M. B.; Shao, L.; Shapiro, B.; Shawhan, P.; Sheperd, A.; Shoemaker, D. H.; Shoemaker, D. M.; Siellez, K.; Siemens, X.; Sieniawska, M.; Sigg, D.; Silva, A. D.; Singer, L. P.; Singh, A.; Singhal, A.; Sintes, A. M.; Slagmolen, B. J. J.; Smith, B.; Smith, J. R.; Smith, R. J. E.; Somala, S.; Son, E. J.; Sonnenberg, J. A.; Sorazu, B.; Sorrentino, F.; Souradeep, T.; Spencer, A. P.; Srivastava, A. K.; Staats, K.; Staley, A.; Steinke, M.; Steinlechner, J.; Steinlechner, S.; Steinmeyer, D.; Stevenson, S. P.; Stone, R.; Stops, D. J.; Strain, K. A.; Stratta, G.; Strigin, S. E.; Strunk, A.; Sturani, R.; Stuver, A. L.; Summerscales, T. Z.; Sun, L.; Sunil, S.; Suresh, J.; Sutton, P. J.; Swinkels, B. L.; Szczepańczyk, M. J.; Tacca, M.; Tait, S. C.; Talbot, C.; Talukder, D.; Tanner, D. B.; Tápai, M.; Taracchini, A.; Tasson, J. D.; Taylor, J. A.; Taylor, R.; Tewari, S. V.; Theeg, T.; Thies, F.; Thomas, E. G.; Thomas, M.; Thomas, P.; Thorne, K. A.; Thrane, E.; Tiwari, S.; Tiwari, V.; Tokmakov, K. V.; Toland, K.; Tonelli, M.; Tornasi, Z.; Torres-Forné, A.; Torrie, C. I.; Töyrä, D.; Travasso, F.; Traylor, G.; Trinastic, J.; Tringali, M. C.; Trozzo, L.; Tsang, K. W.; Tse, M.; Tso, R.; Tsukada, L.; Tsuna, D.; Tuyenbayev, D.; Ueno, K.; Ugolini, D.; Unnikrishnan, C. S.; Urban, A. L.; Usman, S. A.; Vahlbruch, H.; Vajente, G.; Valdes, G.; van Bakel, N.; van Beuzekom, M.; van den Brand, J. F. J.; Van Den Broeck, C.; Vander-Hyde, D. C.; van der Schaaf, L.; van Heijningen, J. V.; van Veggel, A. A.; Vardaro, M.; Varma, V.; Vass, S.; Vasúth, M.; Vecchio, A.; Vedovato, G.; Veitch, J.; Veitch, P. J.; Venkateswara, K.; Venugopalan, G.; Verkindt, D.; Vetrano, F.; Viceré, A.; Viets, A. D.; Vinciguerra, S.; Vine, D. J.; Vinet, J.-Y.; Vitale, S.; Vo, T.; Vocca, H.; Vorvick, C.; Vyatchanin, S. P.; Wade, A. R.; Wade, L. E.; Wade, M.; Walet, R.; Walker, M.; Wallace, L.; Walsh, S.; Wang, G.; Wang, H.; Wang, J. Z.; Wang, W. H.; Wang, Y. F.; Ward, R. L.; Warner, J.; Was, M.; Watchi, J.; Weaver, B.; Wei, L.-W.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Wen, L.; Wessel, E. K.; Weßels, P.; Westerweck, J.; Westphal, T.; Wette, K.; Whelan, J. T.; Whiting, B. F.; Whittle, C.; Wilken, D.; Williams, D.; Williams, R. D.; Williamson, A. R.; Willis, J. L.; Willke, B.; Wimmer, M. H.; Winkler, W.; Wipf, C. C.; Wittel, H.; Woan, G.; Woehler, J.; Wofford, J.; Wong, K. W. K.; Worden, J.; Wright, J. L.; Wu, D. S.; Wysocki, D. M.; Xiao, S.; Yamamoto, H.; Yancey, C. C.; Yang, L.; Yap, M. J.; Yazback, M.; Yu, Hang; Yu, Haocun; Yvert, M.; ZadroŻny, A.; Zanolin, M.; Zelenova, T.; Zendri, J.-P.; Zevin, M.; Zhang, L.; Zhang, M.; Zhang, T.; Zhang, Y.-H.; Zhao, C.; Zhou, M.; Zhou, Z.; Zhu, S. J.; Zhu, X. J.; Zucker, M. E.; Zweizig, J.; LIGO Scientific Collaboration; Virgo Collaboration

2017-12-01

Spinning neutron stars asymmetric with respect to their rotation axis are potential sources of continuous gravitational waves for ground-based interferometric detectors. In the case of known pulsars a fully coherent search, based on matched filtering, which uses the position and rotational parameters obtained from electromagnetic observations, can be carried out. Matched filtering maximizes the signal-to-noise (SNR) ratio, but a large sensitivity loss is expected in case of even a very small mismatch between the assumed and the true signal parameters. For this reason, narrow-band analysis methods have been developed, allowing a fully coherent search for gravitational waves from known pulsars over a fraction of a hertz and several spin-down values. In this paper we describe a narrow-band search of 11 pulsars using data from Advanced LIGO's first observing run. Although we have found several initial outliers, further studies show no significant evidence for the presence of a gravitational wave signal. Finally, we have placed upper limits on the signal strain amplitude lower than the spin-down limit for 5 of the 11 targets over the bands searched; in the case of J1813-1749 the spin-down limit has been beaten for the first time. For an additional 3 targets, the median upper limit across the search bands is below the spin-down limit. This is the most sensitive narrow-band search for continuous gravitational waves carried out so far.

Manipulating charge transfer excited state relaxation and spin crossover in iron coordination complexes with ligand substitution

DOE PAGES

Zhang, Wenkai; Kjaer, Kasper S.; Alonso-Mori, Roberto; ...

2016-08-25

Developing light-harvesting and photocatalytic molecules made with iron could provide a cost effective, scalable, and environmentally benign path for solar energy conversion. To date these developments have been limited by the sub-picosecond metal-to-ligand charge transfer (MLCT) electronic excited state lifetime of iron based complexes due to spin crossover – the extremely fast intersystem crossing and internal conversion to high spin metal-centered excited states. We revitalize a 30 year old synthetic strategy for extending the MLCT excited state lifetimes of iron complexes by making mixed ligand iron complexes with four cyanide (CN –) ligands and one 2,2'-bipyridine (bpy) ligand. This enablesmore » MLCT excited state and metal-centered excited state energies to be manipulated with partial independence and provides a path to suppressing spin crossover. We have combined X-ray Free-Electron Laser (XFEL) Kβ hard X-ray fluorescence spectroscopy with femtosecond time-resolved UV-visible absorption spectroscopy to characterize the electronic excited state dynamics initiated by MLCT excitation of [Fe(CN) 4(bpy)] 2–. The two experimental techniques are highly complementary; the time-resolved UV-visible measurement probes allowed electronic transitions between valence states making it sensitive to ligand-centered electronic states such as MLCT states, whereas the Kβ fluorescence spectroscopy provides a sensitive measure of changes in the Fe spin state characteristic of metal-centered excited states. Here, we conclude that the MLCT excited state of [Fe(CN) 4(bpy)] 2– decays with roughly a 20 ps lifetime without undergoing spin crossover, exceeding the MLCT excited state lifetime of [Fe(2,2'-bipyridine) 3] 2+ by more than two orders of magnitude.« less

Raspberry, not a car: context predictability and a phonological advantage in early and late learners’ processing of speech in noise

PubMed Central

Gor, Kira

2014-01-01

Second language learners perform worse than native speakers under adverse listening conditions, such as speech in noise (SPIN). No data are available on heritage language speakers’ (early naturalistic interrupted learners’) ability to perceive SPIN. The current study fills this gap and investigates the perception of Russian speech in multi-talker babble noise by the matched groups of high- and low-proficiency heritage speakers (HSs) and late second language learners of Russian who were native speakers of English. The study includes a control group of Russian native speakers. It manipulates the noise level (high and low), and context cloze probability (high and low). The results of the SPIN task are compared to the tasks testing the control of phonology, AXB discrimination and picture-word discrimination, and lexical knowledge, a word translation task, in the same participants. The increased phonological sensitivity of HSs interacted with their ability to rely on top–down processing in sentence integration, use contextual cues, and build expectancies in the high-noise/high-context condition in a bootstrapping fashion. HSs outperformed oral proficiency-matched late second language learners on SPIN task and two tests of phonological sensitivity. The outcomes of the SPIN experiment support both the early naturalistic advantage and the role of proficiency in HSs. HSs’ ability to take advantage of the high-predictability context in the high-noise condition was mitigated by their level of proficiency. Only high-proficiency HSs, but not any other non-native group, took advantage of the high-predictability context that became available with better phonological processing skills in high-noise. The study thus confirms high-proficiency (but not low-proficiency) HSs’ nativelike ability to combine bottom–up and top–down cues in processing SPIN. PMID:25566130

Nanoscale magnetic imaging using picosecond thermal gradients

NASA Astrophysics Data System (ADS)

Fuchs, Gregory

Research and development in spintronics is challenged by the lack of table-top magnetic imaging technologies that posses the simultaneous temporal resolution and spatial resolution to characterize magnetization dynamics in emerging spintronic devices. In addition, many of the most exciting magnetic material systems for spintronics are difficult to image with any method. To address this challenge, we developed a spatiotemporal magnetic microscope based on picosecond heat pulses that stroboscopically transduces an in-plane magnetization into a voltage signal. When the magnetic device contains a magnetic metal like FeCoB or NiFe, we use the time-resolved anomalous Nernst effect. When it contains a magnetic insulator/normal metal bilayer like yttrium iron garnet/platinum, we use the combination of the time-resolved longitudinal spin Seebeck effect and the inverse spin Hall effect. We demonstrate that these imaging modalities have time resolutions in the range of 10-100 ps and sensitivities in the range of 0.1 - 0.3° /√{Hz} , which enables not only static magnetic imaging, but also phase-sensitive ferromagnetic resonance imaging. One application of this technology is for magnetic torque vector imaging, which we apply to a spin Hall device. We find an unexpected variation in the spin torque vector that suggests conventional, all-electrical FMR measurements of spin torque vectors can produce a systematic error as large as 30% when quantifying the spin Hall efficiency. Finally, I will describe how time-resolved magnetic imaging can greatly exceed the spatial resolution of optical diffraction. We demonstrate scanning a sharp gold tip to create near-field thermal transfer from a picosecond laser pulse to a magnetic sample as the basis of a nanoscale spatiotemporal microscope. We gratefully acknowledge support from the AFOSR (FA9550-14-1-0243) and the NSF through the Cornell Center for Materials Research (DMR-1120296).

Raspberry, not a car: context predictability and a phonological advantage in early and late learners' processing of speech in noise.

PubMed

Gor, Kira

2014-01-01

Second language learners perform worse than native speakers under adverse listening conditions, such as speech in noise (SPIN). No data are available on heritage language speakers' (early naturalistic interrupted learners') ability to perceive SPIN. The current study fills this gap and investigates the perception of Russian speech in multi-talker babble noise by the matched groups of high- and low-proficiency heritage speakers (HSs) and late second language learners of Russian who were native speakers of English. The study includes a control group of Russian native speakers. It manipulates the noise level (high and low), and context cloze probability (high and low). The results of the SPIN task are compared to the tasks testing the control of phonology, AXB discrimination and picture-word discrimination, and lexical knowledge, a word translation task, in the same participants. The increased phonological sensitivity of HSs interacted with their ability to rely on top-down processing in sentence integration, use contextual cues, and build expectancies in the high-noise/high-context condition in a bootstrapping fashion. HSs outperformed oral proficiency-matched late second language learners on SPIN task and two tests of phonological sensitivity. The outcomes of the SPIN experiment support both the early naturalistic advantage and the role of proficiency in HSs. HSs' ability to take advantage of the high-predictability context in the high-noise condition was mitigated by their level of proficiency. Only high-proficiency HSs, but not any other non-native group, took advantage of the high-predictability context that became available with better phonological processing skills in high-noise. The study thus confirms high-proficiency (but not low-proficiency) HSs' nativelike ability to combine bottom-up and top-down cues in processing SPIN.

Spin-dependent transport phenomena in organic semiconductors

NASA Astrophysics Data System (ADS)

Bergeson, Jeremy D.

Thin-film organic semiconductors transport can have an anomalously high sensitivity to low magnetic fields. Such a response is unexpected considering that thermal fluctuation energies are greater than the energy associated with the intrinsic spin of charge carriers at a modest magnetic field of 100 Oe by a factor of more than 104 at room temperature and is still greater by 102 even at liquid helium temperatures. Nevertheless, we report experimental characterization of (1) spin-dependent injection, detection and transport of spin-polarized current through organic semiconductors and (2) the influence of a magnetic field on the spin dynamics of recombination-limited transport. The first focus of this work was accomplished by fabricating basic spin-valve devices consisting of two magnetic layers spatially separated by a nonmagnetic organic semiconductor. The spin-valve effect is a change in electrical resistance due to the magnetizations of the magnetic layers changing from parallel to antiparallel alignment, or vice versa. The conductivities of the metallic contacts and that of the semiconductor differed by many orders of magnitude, which inhibited the injection of a spin-polarized current from the magnet into the nonmagnet. We successfully overcame the problem of conductivity mismatch by inserting ultra-thin tunnel barriers at the metal/semiconductor interfaces which aided in yielding a ˜20% spin-valve effect at liquid helium temperatures and the effect persisted up to 150 K. We built on this achievement by constructing spin valves where one of the metallic contacts was replaced by the organic-based magnetic semiconductor vanadium tetracyanoethylene (V[TCNE]2). At 10 K these devices produced the switching behavior of the spin-valve effect. The second focus of this work was the bulk magnetoresistance (MR) of small molecule, oligomer and polymer organic semiconductors in thin-film structures. At room temperature the resistance can change up to 8% at 100 Oe and 15% at 1000 Oe. Depending on parameters such as temperature, layer thickness, or applied voltage, the resistance of these materials may increase or decrease as a function of field. A model for this phenomenon, termed magnetoresistance by the interconversion of singlets and triplets (MIST), is developed to account for this anomalous behavior. This model predicts that increasing the spin-orbit coupling in the organic semiconductor should decrease the magnitude of the MR. In an experiment where the small molecule Alq3 was doped with phosphorescent sensitizers, to increase the spin-orbit coupling, the MR was observed to decrease by an order of magnitude or more, depending on the doping. In addition to low-magnetic-field effects, we show the experimental observation of high-field MR in devices with and without magnetic contacts. To the best of our knowledge, we are the first to report (1) a tunnel-barrier-assisted spin-valve effect into an organic semiconductor using partially polarized metallic magnetic electrodes and (2) an experimental characterization of the central impact of the hyperfine interaction and spin-orbit coupling on MR in organic semiconductors.

Spin-dependent heat and thermoelectric currents in a Rashba ring coupled to a photon cavity

NASA Astrophysics Data System (ADS)

Abdullah, Nzar Rauf; Tang, Chi-Shung; Manolescu, Andrei; Gudmundsson, Vidar

2018-01-01

Spin-dependent heat and thermoelectric currents in a quantum ring with Rashba spin-orbit interaction placed in a photon cavity are theoretically calculated. The quantum ring is coupled to two external leads with different temperatures. In a resonant regime, with the ring structure in resonance with the photon field, the heat and the thermoelectric currents can be controlled by the Rashba spin-orbit interaction. The heat current is suppressed in the presence of the photon field due to contribution of the two-electron and photon replica states to the transport while the thermoelectric current is not sensitive to changes in parameters of the photon field. Our study opens a possibility to use the proposed interferometric device as a tunable heat current generator in the cavity photon field.

Circular polarization switching and bistability in an optically injected 1300 nm spin-vertical cavity surface emitting laser

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alharthi, S. S., E-mail: ssmalh@essex.ac.uk; Henning, I. D.; Adams, M. J.

We report the experimental observation of circular polarization switching (PS) and polarization bistability (PB) in a 1300 nm dilute nitride spin-vertical cavity surface emitting laser (VCSEL). We demonstrate that the circularly polarized optical signal at 1300 nm can gradually or abruptly switch the polarization ellipticity of the spin-VCSEL from right-to-left circular polarization and vice versa. Moreover, different forms of PS and PB between right- and left-circular polarizations are observed by controlling the injection strength and the initial wavelength detuning. These results obtained at the telecom wavelength of 1300 nm open the door for novel uses of spin-VCSELs in polarization sensitive applications in futuremore » optical systems.« less

Controlled drug delivery from composites of nanostructured porous silicon and poly(L-lactide).

PubMed

McInnes, Steven J P; Irani, Yazad; Williams, Keryn A; Voelcker, Nicolas H

2012-07-01

Porous silicon (pSi) and poly(L-lactide) (PLLA) both display good biocompatibility and tunable degradation behavior, suggesting that composites of both materials are suitable candidates as biomaterials for localized drug delivery into the human body. The combination of a pliable and soft polymeric material with a hard inorganic porous material of high drug loading capacity may engender improved control over degradation and drug release profiles and be beneficial for the preparation of advanced drug delivery devices and biodegradable implants or scaffolds. In this work, three different pSi and PLLA composite formats were prepared. The first format involved grafting PLLA from pSi films via surface-initiated ring-opening polymerization (pSi-PLLA [grafted]). The second format involved spin coating a PLLA solution onto oxidized pSi films (pSi-PLLA [spin-coated]) and the third format consisted of a melt-cast PLLA monolith containing dispersed pSi microparticles (pSi-PLLA [monoliths]). The surface characterization of these composites was performed via infrared spectroscopy, scanning electron microscopy, atomic force microscopy and water contact angle measurements. The composite materials were loaded with a model cytotoxic drug, camptothecin (CPT). Drug release from the composites was monitored via fluorimetry and the release profiles of CPT showed distinct characteristics for each of the composites studied. In some cases, controlled CPT release was observed for more than 5 days. The PLLA spin coat on pSi and the PLLA monolith containing pSi microparticles both released a CPT payload in accordance with the Higuchi and Ritger-Peppas release models. Composite materials were also brought into contact with human lens epithelial cells to determine the extent of cytotoxicity. We observed that all the CPT containing materials were highly efficient at releasing bioactive CPT, based on the cytotoxicity data.

Constraining Δ G at Low-x with Double Longitudinal Spin Asymmetries for Forward Hadron and Di-Hadron Pairs in PHENIX

NASA Astrophysics Data System (ADS)

Wolin, Scott; Phenix Collaboration

2011-10-01

The gluon polarization, ΔG =∫01 g(x) dx , is constrained in the region 0 . 05 < x < 0 . 2 from measurements of double spin asymmetries, ALL, for inclusive hadron and jet production at mid-rapidity at RHIC. Theoretical analysis of experimental results shows that ∫0. 05 0 . 2 Δg(x) dx = 0 .013-0 . 120 + 0 . 106 . This is not large enough to account for the missing proton spin. However, Δg(x) is unconstrained at low-x, and a measurement sensitive to this region will provide important input for future global analyses. The measurement of ALL for inclusive hadrons and di-hadrons with the Muon Piston Calorimeter (MPC) 3 . 1 < η < 3 . 9 provides this sensitivity down to x 10-3 and will lead to the first constraints of Δg(x) at x < 0 . 05 . The di-hadron measurement is especially interesting as it is sensitive to the sign of ΔG and best constrains the parton kinematics giving the most precise access to xgluon. The inclusive measurement provides a looser constraint on the event kinematics but has a higher yield. We will present the status of these measurements for the 2009 dataset at √{ s} = 500 GeV and √{ s} = 200 GeV.

T1ρ magnetic resonance: basic physics principles and applications in knee and intervertebral disc imaging.

PubMed

Wáng, Yì-Xiáng J; Zhang, Qinwei; Li, Xiaojuan; Chen, Weitian; Ahuja, Anil; Yuan, Jing

2015-12-01

T1ρ relaxation time provides a new contrast mechanism that differs from T1- and T2-weighted contrast, and is useful to study low-frequency motional processes and chemical exchange in biological tissues. T1ρ imaging can be performed in the forms of T1ρ-weighted image, T1ρ mapping and T1ρ dispersion. T1ρ imaging, particularly at low spin-lock frequency, is sensitive to B0 and B1 inhomogeneity. Various composite spin-lock pulses have been proposed to alleviate the influence of field inhomogeneity so as to reduce the banding-like spin-lock artifacts. T1ρ imaging could be specific absorption rate (SAR) intensive and time consuming. Efforts to address these issues and speed-up data acquisition are being explored to facilitate wider clinical applications. This paper reviews the T1ρ imaging's basic physic principles, as well as its application for cartilage imaging and intervertebral disc imaging. Compared to more established T2 relaxation time, it has been shown that T1ρ provides more sensitive detection of proteoglycan (PG) loss at early stages of cartilage degeneration. T1ρ has also been shown to provide more sensitive evaluation of annulus fibrosis (AF) degeneration of the discs.

T1ρ magnetic resonance: basic physics principles and applications in knee and intervertebral disc imaging

PubMed Central

Zhang, Qinwei; Li, Xiaojuan; Chen, Weitian; Ahuja, Anil; Yuan, Jing

2015-01-01

T1ρ relaxation time provides a new contrast mechanism that differs from T1- and T2-weighted contrast, and is useful to study low-frequency motional processes and chemical exchange in biological tissues. T1ρ imaging can be performed in the forms of T1ρ-weighted image, T1ρ mapping and T1ρ dispersion. T1ρ imaging, particularly at low spin-lock frequency, is sensitive to B0 and B1 inhomogeneity. Various composite spin-lock pulses have been proposed to alleviate the influence of field inhomogeneity so as to reduce the banding-like spin-lock artifacts. T1ρ imaging could be specific absorption rate (SAR) intensive and time consuming. Efforts to address these issues and speed-up data acquisition are being explored to facilitate wider clinical applications. This paper reviews the T1ρ imaging’s basic physic principles, as well as its application for cartilage imaging and intervertebral disc imaging. Compared to more established T2 relaxation time, it has been shown that T1ρ provides more sensitive detection of proteoglycan (PG) loss at early stages of cartilage degeneration. T1ρ has also been shown to provide more sensitive evaluation of annulus fibrosis (AF) degeneration of the discs. PMID:26807369

Singlet-Fission-Sensitized Hybrid Thin-Films For Next-Generation Photovoltaics

DTIC Science & Technology

2016-04-12

evaporators and a spin-coater was constructed. In order to characterize PV devices, a solar -simulator, 1. REPORT DATE (DD-MM-YYYY) 4. TITLE AND...with thermal evaporators and a spin-coater was constructed. In order to characterize PV devices, a solar -simulator, semiconductor parameter analyzer...SECURITY CLASSIFICATION OF: This grant enabled the acquisition of equipment for the fabrication of organic and nanocrystal based photovoltaic ( PV

Injectable biocompatible and biodegradable pH-responsive hollow particle gels containing poly(acrylic acid): the effect of copolymer composition on gel properties.

PubMed

Halacheva, Silvia S; Adlam, Daman J; Hendow, Eseelle K; Freemont, Tony J; Hoyland, Judith; Saunders, Brian R

2014-05-12

The potential of various pH-responsive alkyl (meth)acrylate ester- and (meth)acrylic acid-based copolymers, including poly(methyl methacrylate-co-acrylic acid) (PMMA-AA) and poly(n-butyl acrylate-co-methacrylic acid) (PBA-MAA), to form pH-sensitive biocompatible and biodegradable hollow particle gel scaffolds for use in non-load-bearing soft tissue regeneration have been explored. The optimal copolymer design criteria for preparation of these materials have been established. Physical gels which are both pH- and redox-sensitive were formed only from PMMA-AA copolymers. MMA is the optimal hydrophobic monomer, whereas the use of various COOH-containing monomers, e.g., MAA and AA, will always induce a pH-triggered physical gelation. The PMMA-AA gels were prepared at physiological pH range from concentrated dispersions of swollen, hollow, polymer-based particles cross-linked with either cystamine (CYS) or 3,3'-dithiodipropionic acid dihydrazide (DTP). A linear relationship between particle swelling ratios, gel elasticity, and ductility was observed. The PMMA-AA gels with lower AA contents feature lower swelling ratios, mechanical strengths, and ductilities. Increasing the swelling ratio (e.g., through increasing AA content) decreased the intraparticle elasticity; however, intershell contact and gel elasticity were found to increase. The mechanical properties and performance of the gels were tuneable upon varying the copolymers' compositions and the structure of the cross-linker. Compared to PMMA-AA/CYS, the PMMA-AA/DTP gels were more elastic and ductile. The biodegradability and cytotoxicity of the new hollow particle gels were tested for the first time and related to their composition, mechanical properties, and morphology. The new PMMA-AA/CYS and PMMA-AA/DTP gels have shown good biocompatibility, biodegradability, strength, and interconnected porosity and therefore have good potential as a tissue repair agent.

Magneto-optical imaging of thin magnetic films using spins in diamond

NASA Astrophysics Data System (ADS)

Simpson, David A.; Tetienne, Jean-Philippe; McCoey, Julia M.; Ganesan, Kumaravelu; Hall, Liam T.; Petrou, Steven; Scholten, Robert E.; Hollenberg, Lloyd C. L.

2016-03-01

Imaging the fields of magnetic materials provides crucial insight into the physical and chemical processes surrounding magnetism, and has been a key ingredient in the spectacular development of magnetic data storage. Existing approaches using the magneto-optic Kerr effect, x-ray and electron microscopy have limitations that constrain further development, and there is increasing demand for imaging and characterisation of magnetic phenomena in real time with high spatial resolution. Here we show how the magneto-optical response of an array of negatively-charged nitrogen-vacancy spins in diamond can be used to image and map the sub-micron stray magnetic field patterns from thin ferromagnetic films. Using optically detected magnetic resonance, we demonstrate wide-field magnetic imaging over 100 × 100 μm2 with sub-micron spatial resolution at video frame rates, under ambient conditions. We demonstrate an all-optical spin relaxation contrast imaging approach which can image magnetic structures in the absence of an applied microwave field. Straightforward extensions promise imaging with sub-μT sensitivity and sub-optical spatial and millisecond temporal resolution. This work establishes practical diamond-based wide-field microscopy for rapid high-sensitivity characterisation and imaging of magnetic samples, with the capability for investigating magnetic phenomena such as domain wall and skyrmion dynamics and the spin Hall effect in metals.

Ultra-sensitive atomic magnetometer for studying magnetization fields produced by hyperpolarized helium-3

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zou, Sheng; Zhang, Hong; Fang, Jian-cheng, E-mail: fangjiancheng@buaa.edu.cn

2016-04-14

An ingenious approach to acquire the absolute magnetization fields produced by polarized atoms has been presented in this paper. The method was based on detection of spin precession signal of the hyperpolarized helium-3 with ultra-sensitive atomic magnetometer of potassium by referring to time-domain analysis. At first, dynamic responses of the mixed spin ensembles in the presence of variant external magnetic fields have been analyzed by referring to the Bloch equation. Subsequently, the relevant equipment was established to achieve the functions of hyperpolarizing helium-3 and detecting the precession of spin-polarized noble gas. By analyzing the transient response of the magnetometer inmore » time domain, we obtained the relevant damping ratio and natural frequency. When the value of damping ratio reached the maximum value of 0.0917, the combined atomic magnetometer was in equilibrium. We draw a conclusion from the steady response: the magnetization fields of the polarized electrons and the hyperpolarized nuclei were corresponding 16.12 nT and 90.74 nT. Under this situation, the nuclear magnetization field could offset disturbing magnetic fields perpendicular to the orientation of the electronic polarization, and it preserved the electronic spin staying in a stable axis. Therefore, the combined magnetometer was particularly attractive for inertial measurements.« less

Magnetic adatoms in two and four terminal graphene nanoribbons: A comparison between their spin polarized transport

NASA Astrophysics Data System (ADS)

Ganguly, Sudin; Basu, Saurabh

2018-04-01

We study the charge and spin transport in two and four terminal graphene nanoribbons (GNR) decorated with random distribution of magnetic adatoms. The inclusion of the magnetic adatoms generates only the z-component of the spin polarized conductance via an exchange bias in the absence of Rashba spin-orbit interaction (SOI), while in presence of Rashba SOI, one is able to create all the three (x, y and z) components. This has important consequences for possible spintronic applications. The charge conductance shows interesting behaviour near the zero of the Fermi energy. Where in presence of magnetic adatoms the familiar plateau at 2e2 / h vanishes, thereby transforming a quantum spin Hall insulating phase to an ordinary insulator. The local charge current and the local spin current provide an intuitive idea on the conductance features of the system. We found that, the local charge current is independent of Rashba SOI, while the three components of the local spin currents are sensitive to Rashba SOI. Moreover the fluctuations of the spin polarized conductance are found to be useful quantities as they show specific trends, that is, they enhance with increasing adatom densities. A two terminal GNR device seems to be better suited for possible spintronic applications.

A 3He-129Xe co-magnetometer probed by a Rb magnetometer with Ramsey-pulse technique

NASA Astrophysics Data System (ADS)

Sheng, Dong; Kabcenell, Aaron; Romalis, Michael

2013-05-01

We report the recent progress in development of a new kind of co-magnetometer, benifiting from both the long spin coherence time of a noble gas and a highly sensitive alkali metal magnetometer. Due to the Fermi-contact interaction between alkali metal electron spin and noble gas nuclear spin the effective magnetization of the noble gas is enhanced by a factor of 6 to 600, allowing near quantum-limited detection of nuclear spins. Collisions between polarized alkali atoms and noble gas also introduce a large shift to the nuclear spin precession frequency. We reduce this effect by using Ramsey pulse techniques to measure the noble gas spin precession frequency ``in the dark'' by turning off the pumping laser between Ramsey pulses. A furthur reduction of the back-hyperpolarization from the noble gas can be achieved by controlling the cell temperature on short time scale. We showed that a 3He-129Xe Ramsey co-magnetometer is effective in cancelling fluctuations of external magnetic fields and gradients and developed cells with sufficient 129Xe T2 time without surface coatings. The new co-magnetometer has potential applications for many precision measurements, such as searches for spin-gravity couplings, electric dipole moments, and nuclear spin gyroscopes. Supported by DARPA.

Enzyme sensitive smart inulin-dehydropeptide conjugate self-assembles into nanostructures useful for targeted delivery of ornidazole.

PubMed

Shivhare, Kriti; Garg, Charu; Priyam, Ayushi; Gupta, Alka; Sharma, Ashwani Kumar; Kumar, Pradeep

2018-01-01

Molecular self-assembly of biodegradable amphiphilic polymers allows rational design of biocompatible nanomaterials for drug delivery. Use of substituted polysaccharides for such applications offers the ease of design and synthesis, and provides higher biofunctionality and biocompatibility to nanomaterials. The present work focuses on the synthesis, characterization and potential biomedical applications of self-assembled polysaccharide-based materials. We demonstrated that the synthesized amphiphilic inulin self-assembled in aqueous medium into nanostructures with average size in the range of 146-486nm and encapsulated hydrophobic therapeutic molecule, ornidazole. Hydrophophic dehydropeptide was conjugated with inulin via a biocompatible ester linkage. Dehydrophenylalanine, an unusual amino acid, was incorporated in the peptide to make it stable at a broader range of pH as well as against proteases. The resulting core-shell type of nanostructures could encapsulate ornidazole in the hydrophobic core and released it in a controlled fashion. By taking the advantage of inulin, which gets degraded in the colon by colonic bacteria, the effect of enzyme, inulinase, present in the microflora of the large intestine, on inulin-peptide degradation followed by drug release has been studied. Altogether, small peptide conjugated to inulin offers novel scaffold for the future design of nanostructures with potential applications in the field of targeted drug delivery. Copyright © 2017 Elsevier B.V. All rights reserved.

Facile synthesis and luminescence characteristics of high-quality CdS: Eu/ZnS core/shell nanocrystals with biocompatibility.

PubMed

Zhang, Kexin; Zhang, Rui; Yu, Yaxin; Sun, Shuqing

2012-04-01

In this paper, we report a facile method to synthesize high quality CdS: Eu nanocrystals (NCs) and CdS: Eu/ZnS NCs with strong photoluminescence (PL). The influence of various experimental variables including the concentration of Eu3+ ions, the reaction time and the reaction temperature were investigated systematically. In addition, the PL properties of CdS: Eu NCs exhibited pH sensitive. Under the acid condition, pH value of the CdS: Eu NCs solution played an important role in determining PL emission intensity. However, under the alkaline condition, the obtained CdS: Eu NCs exhibited a tunable PL emission wavelength (from 490 nm to 610 nm) when pH value was adjusted from pH 7 to 10. After coating with ZnS shell, the CdS: Eu/ZnS NCs showed enhanced PL intensity compare with one of the CdS: Eu NCs. The CdS: Eu NCs and CdS: Eu/ZnS NCs were characterized by X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). In addition, the biocompatibility of these NCs was measured by hemolytic test, which indicated that CdS: Eu/ZnS NCs were more biocompatible than CdS: Eu NCs at the same conditions. It can be expected that CdS: Eu/ZnS NCs are promising biolabeling materials.

Hysteresis-free spin valves with a noncollinear configuration of magnetic anisotropy

NASA Astrophysics Data System (ADS)

Naumova, L. I.; Milyaev, M. A.; Chernyshova, T. A.; Proglyado, V. V.; Kamenskii, I. Yu.; Ustinov, V. V.

2014-06-01

A noncollinear configuration of magnetic anisotropy in spin valves with strong and weak interlayer couplings has been formed by annealing and cooling in a magnetic field. The dependence of the low-field magnetoresistance hysteresis loop width on the angle between the applied magnetic field and the principal axes of the magnetic anisotropy in a spin valve has been investigated. It has been found that, only in the case of a strong ferromagnetic interlayer coupling, the formation of a noncollinear configuration of the magnetic anisotropy provides a hysteresis-free character of the magnetization reversal of the free layer with retaining the maximum magnetoresistance and magnetoresistive sensitivity.

Note: Force- and torque-detection of high frequency electron spin resonance using a membrane-type surface-stress sensor

NASA Astrophysics Data System (ADS)

Takahashi, Hideyuki; Ishimura, Kento; Okamoto, Tsubasa; Ohmichi, Eiji; Ohta, Hitoshi

2018-03-01

We developed a practical useful method for force- and torque-detected electron spin resonance (FDESR/TDESR) spectroscopy in the millimeter wave frequency region. This method uses a commercially available membrane-type surface-stress (MSS) sensor. The MSS is composed of a silicon membrane supported by four beams in which piezoresistive paths are integrated for detecting the deformation of the membrane. Although this device has a lower spin sensitivity than a microcantilever, it offers several distinct advantages, including mechanical strength, ease of use, and versatility. These advantages make this device suitable for practical applications that require FDESR/TDESR.

Onset of Spin Polarization in Four-Gate Quantum Point Contacts

NASA Astrophysics Data System (ADS)

Jones, Alex

A series of simulations which utilize a Non-equilibrium Green's function (NEGF) formalism is suggested which can provide indirect evidence of the fine and non-local electrostatic tuning of the onset of spin polarization in two closely spaced quantum point contacts (QPCs) that experience a phenomenon known as lateral spin-orbit coupling (LSOC). Each of the QPCs that create the device also has its own pair of side gates (SGs) which are in-plane with the device channel. Numerical simulations of the conductance of the two closely spaced QPCs or four-gate QPC are carried out for different biasing conditions applied to two leftmost and rightmost SGs. Conductance plots are then calculated as a function of the variable, Vsweep, which is the common sweep voltage applied to the QPC. When Vsweep is only applied to two of the four side gates, the plots show several conductance anomalies, i.e., below G0 = 2e2/h, characterized by intrinsic bistability, i.e., hysteresis loops due to a difference in the conductance curves for forward and reverse common voltage sweep simulations. The appearance of hysteresis loops is attributed to the co-existence of multistable spin textures in the narrow channel of the four-gate QPC. The shape, location, and number of hysteresis loops are very sensitive to the biasing conditions on the four SGs. The shape and size of the conductance anomalies and hysteresis loops are shown to change when the biasing conditions on the leftmost and rightmost SGs are swapped, a rectifying behavior providing an additional indirect evidence for the onset of spontaneous spin polarization in nanoscale devices made of QPCs. The results of the simulations reveal that the occurrence and fine tuning of conductance anomalies in QPC structures are highly sensitive to the non-local action of closely spaced SGs. It is therefore imperative to take into account this proximity effect in the design of all electrical spin valves making use of middle gates to fine tune the spin precession between QPC based spin injector and detector contacts.

Anomalous spin-dependent tunneling statistics in Fe/MgO/Fe junctions induced by disorder at the interface

NASA Astrophysics Data System (ADS)

Yan, Jiawei; Wang, Shizhuo; Xia, Ke; Ke, Youqi

2018-01-01

We present first-principles analysis of interfacial disorder effects on spin-dependent tunneling statistics in thin Fe/MgO/Fe magnetic tunnel junctions. We find that interfacial disorder scattering can significantly modulate the tunneling statistics in the minority spin of the parallel configuration (PC) while all other spin channels remain dominated by the Poissonian process. For the minority-spin channel of PC, interfacial disorder scattering favors the formation of resonant tunneling channels by lifting the limitation of symmetry conservation at low concentration, presenting an important sub-Poissonian process in PC, but is destructive to the open channels at high concentration. We find that the important modulation of tunneling statistics is independent of the type of interfacial disorder. A bimodal distribution function of transmission with disorder dependence is introduced and fits very well our first-principles results. The increase of MgO thickness can quickly change the tunneling from a sub-Poissonian to Poissonian dominated process in the minority spin of PC with disorder. Our results provide a sensitive detection method of an ultralow concentration of interfacial defects.

Study of the spin and parity of the Higgs boson in diboson decays with the ATLAS detector.

PubMed

Aad, G; Abbott, B; Abdallah, J; Abdinov, O; Aben, R; Abolins, M; AbouZeid, O S; Abramowicz, H; Abreu, H; Abreu, R; Abulaiti, Y; Acharya, B S; Adamczyk, L; Adams, D L; Adelman, J; Adomeit, S; Adye, T; Affolder, A A; Agatonovic-Jovin, T; Agricola, J; Aguilar-Saavedra, J A; Ahlen, S P; Ahmadov, F; Aielli, G; Akerstedt, H; Åkesson, T P A; Akimov, A V; Alberghi, G L; Albert, J; Albrand, S; Alconada Verzini, M J; Aleksa, M; Aleksandrov, I N; Alexa, C; Alexander, G; Alexopoulos, T; Alhroob, M; Alimonti, G; Alio, L; Alison, J; Alkire, S P; Allbrooke, B M M; Allport, P P; Aloisio, A; Alonso, A; Alonso, F; Alpigiani, C; Altheimer, A; Alvarez Gonzalez, B; Álvarez Piqueras, D; Alviggi, M G; Amadio, B T; Amako, K; Amaral Coutinho, Y; Amelung, C; Amidei, D; Amor Dos Santos, S P; Amorim, A; Amoroso, S; Amram, N; Amundsen, G; Anastopoulos, C; Ancu, L S; Andari, N; Andeen, T; Anders, C F; Anders, G; Anders, J K; Anderson, K J; Andreazza, A; Andrei, V; Angelidakis, S; Angelozzi, I; Anger, P; Angerami, A; Anghinolfi, F; Anisenkov, A V; Anjos, N; Annovi, A; Antonelli, M; Antonov, A; Antos, J; Anulli, F; Aoki, M; Aperio Bella, L; Arabidze, G; Arai, Y; Araque, J P; Arce, A T H; Arduh, F A; Arguin, J-F; Argyropoulos, S; Arik, M; Armbruster, A J; Arnaez, O; Arnal, V; Arnold, H; Arratia, M; Arslan, O; Artamonov, A; Artoni, G; Asai, S; Asbah, N; Ashkenazi, A; Åsman, B; Asquith, L; Assamagan, K; Astalos, R; Atkinson, M; Atlay, N B; Auerbach, B; Augsten, K; Aurousseau, M; Avolio, G; Axen, B; Ayoub, M K; Azuelos, G; Baak, M A; Baas, A E; Bacci, C; Bachacou, H; Bachas, K; Backes, M; Backhaus, M; Bagiacchi, P; Bagnaia, P; Bai, Y; Bain, T; Baines, J T; Baker, O K; Baldin, E M; Balek, P; Balestri, T; Balli, F; Banas, E; Banerjee, Sw; Bannoura, A A E; Bansil, H S; Barak, L; Barberio, E L; Barberis, D; Barbero, M; Barillari, T; Barisonzi, M; Barklow, T; Barlow, N; Barnes, S L; Barnett, B M; Barnett, R M; Barnovska, Z; Baroncelli, A; Barone, G; Barr, A J; Barreiro, F; Barreiro Guimarães da Costa, J; Bartoldus, R; Barton, A E; Bartos, P; Basalaev, A; Bassalat, A; Basye, A; Bates, R L; Batista, S J; Batley, J R; Battaglia, M; Bauce, M; Bauer, F; Bawa, H S; Beacham, J B; Beattie, M D; Beau, T; Beauchemin, P H; Beccherle, R; Bechtle, P; Beck, H P; Becker, K; Becker, M; Becker, S; Beckingham, M; Becot, C; Beddall, A J; Beddall, A; Bednyakov, V A; Bee, C P; Beemster, L J; Beermann, T A; Begel, M; Behr, J K; Belanger-Champagne, C; Bell, W H; Bella, G; Bellagamba, L; Bellerive, A; Bellomo, M; Belotskiy, K; Beltramello, O; Benary, O; Benchekroun, D; Bender, M; Bendtz, K; Benekos, N; Benhammou, Y; Benhar Noccioli, E; Benitez Garcia, J A; Benjamin, D P; Bensinger, J R; Bentvelsen, S; Beresford, L; Beretta, M; Berge, D; Bergeaas Kuutmann, E; Berger, N; Berghaus, F; Beringer, J; Bernard, C; Bernard, N R; Bernius, C; Bernlochner, F U; Berry, T; Berta, P; Bertella, C; Bertoli, G; Bertolucci, F; Bertsche, C; Bertsche, D; Besana, M I; Besjes, G J; Bessidskaia Bylund, O; Bessner, M; Besson, N; Betancourt, C; Bethke, S; Bevan, A J; Bhimji, W; Bianchi, R M; Bianchini, L; Bianco, M; Biebel, O; Biedermann, D; Bieniek, S P; Biglietti, M; Bilbao De Mendizabal, J; Bilokon, H; Bindi, M; Binet, S; Bingul, A; Bini, C; Biondi, S; Black, C W; Black, J E; Black, K M; Blackburn, D; Blair, R E; Blanchard, J-B; Blanco, J E; Blazek, T; Bloch, I; Blocker, C; Blum, W; Blumenschein, U; Bobbink, G J; Bobrovnikov, V S; Bocchetta, S S; Bocci, A; Bock, C; Boehler, M; Bogaerts, J A; Bogavac, D; Bogdanchikov, A G; Bohm, C; Boisvert, V; Bold, T; Boldea, V; Boldyrev, A S; Bomben, M; Bona, M; Boonekamp, M; Borisov, A; Borissov, G; Borroni, S; Bortfeldt, J; Bortolotto, V; Bos, K; Boscherini, D; Bosman, M; Boudreau, J; Bouffard, J; Bouhova-Thacker, E V; Boumediene, D; Bourdarios, C; Bousson, N; Boveia, A; Boyd, J; Boyko, I R; Bozic, I; Bracinik, J; Brandt, A; Brandt, G; Brandt, O; Bratzler, U; Brau, B; Brau, J E; Braun, H M; Brazzale, S F; Breaden Madden, W D; Brendlinger, K; Brennan, A J; Brenner, L; Brenner, R; Bressler, S; Bristow, K; Bristow, T M; Britton, D; Britzger, D; Brochu, F M; Brock, I; Brock, R; Bronner, J; Brooijmans, G; Brooks, T; Brooks, W K; Brosamer, J; Brost, E; Brown, J; Bruckman de Renstrom, P A; Bruncko, D; Bruneliere, R; Bruni, A; Bruni, G; Bruschi, M; Bruscino, N; Bryngemark, L; Buanes, T; Buat, Q; Buchholz, P; Buckley, A G; Buda, S I; Budagov, I A; Buehrer, F; Bugge, L; Bugge, M K; Bulekov, O; Bullock, D; Burckhart, H; Burdin, S; Burghgrave, B; Burke, S; Burmeister, I; Busato, E; Büscher, D; Büscher, V; Bussey, P; Butler, J M; Butt, A I; Buttar, C M; Butterworth, J M; Butti, P; Buttinger, W; Buzatu, A; Buzykaev, A R; Cabrera Urbán, S; Caforio, D; Cairo, V M; Cakir, O; Calafiura, P; Calandri, A; Calderini, G; Calfayan, P; Caloba, L P; Calvet, D; Calvet, S; Camacho Toro, R; Camarda, S; Camarri, P; Cameron, D; Caminal Armadans, R; Campana, S; Campanelli, M; Campoverde, A; Canale, V; Canepa, A; Cano Bret, M; Cantero, J; Cantrill, R; Cao, T; Capeans Garrido, M D M; Caprini, I; Caprini, M; Capua, M; Caputo, R; Cardarelli, R; Cardillo, F; Carli, T; Carlino, G; Carminati, L; Caron, S; Carquin, E; Carrillo-Montoya, G D; Carter, J R; Carvalho, J; Casadei, D; Casado, M P; Casolino, M; Castaneda-Miranda, E; Castelli, A; Castillo Gimenez, V; Castro, N F; Catastini, P; Catinaccio, A; Catmore, J R; Cattai, A; Caudron, J; Cavaliere, V; Cavalli, D; Cavalli-Sforza, M; Cavasinni, V; Ceradini, F; Cerio, B C; Cerny, K; Cerqueira, A S; Cerri, A; Cerrito, L; Cerutti, F; Cerv, M; Cervelli, A; Cetin, S A; Chafaq, A; Chakraborty, D; Chalupkova, I; Chang, P; Chapman, J D; Charlton, D G; Chau, C C; Chavez Barajas, C A; Cheatham, S; Chegwidden, A; Chekanov, S; Chekulaev, S V; Chelkov, G A; Chelstowska, M A; Chen, C; Chen, H; Chen, K; Chen, L; Chen, S; Chen, X; Chen, Y; Cheng, H C; Cheng, Y; Cheplakov, A; Cheremushkina, E; Cherkaoui El Moursli, R; Chernyatin, V; Cheu, E; Chevalier, L; Chiarella, V; Childers, J T; Chiodini, G; Chisholm, A S; Chislett, R T; Chitan, A; Chizhov, M V; Choi, K; Chouridou, S; Chow, B K B; Christodoulou, V; Chromek-Burckhart, D; Chudoba, J; Chuinard, A J; Chwastowski, J J; Chytka, L; Ciapetti, G; Ciftci, A K; Cinca, D; Cindro, V; Cioara, I A; Ciocio, A; Cirotto, F; Citron, Z H; Ciubancan, M; Clark, A; Clark, B L; Clark, P J; Clarke, R N; Cleland, W; Clement, C; Coadou, Y; Cobal, M; Coccaro, A; Cochran, J; Coffey, L; Cogan, J G; Cole, B; Cole, S; Colijn, A P; Collot, J; Colombo, T; Compostella, G; Conde Muiño, P; Coniavitis, E; Connell, S H; Connelly, I A; Consonni, S M; Consorti, V; Constantinescu, S; Conta, C; Conti, G; Conventi, F; Cooke, M; Cooper, B D; Cooper-Sarkar, A M; Cornelissen, T; Corradi, M; Corriveau, F; Corso-Radu, A; Cortes-Gonzalez, A; Cortiana, G; Costa, G; Costa, M J; Costanzo, D; Côté, D; Cottin, G; Cowan, G; Cox, B E; Cranmer, K; Cree, G; Crépé-Renaudin, S; Crescioli, F; Cribbs, W A; Crispin Ortuzar, M; Cristinziani, M; Croft, V; Crosetti, G; Cuhadar Donszelmann, T; Cummings, J; Curatolo, M; Cuthbert, C; Czirr, H; Czodrowski, P; D'Auria, S; D'Onofrio, M; Da Cunha Sargedas De Sousa, M J; Da Via, C; Dabrowski, W; Dafinca, A; Dai, T; Dale, O; Dallaire, F; Dallapiccola, C; Dam, M; Dandoy, J R; Dang, N P; Daniells, A C; Danninger, M; Dano Hoffmann, M; Dao, V; Darbo, G; Darmora, S; Dassoulas, J; Dattagupta, A; Davey, W; David, C; Davidek, T; Davies, E; Davies, M; Davison, P; Davygora, Y; Dawe, E; Dawson, I; Daya-Ishmukhametova, R K; De, K; de Asmundis, R; De Castro, S; De Cecco, S; De Groot, N; de Jong, P; De la Torre, H; De Lorenzi, F; De Nooij, L; De Pedis, D; De Salvo, A; De Sanctis, U; De Santo, A; De Vivie De Regie, J B; Dearnaley, W J; Debbe, R; Debenedetti, C; Dedovich, D V; Deigaard, I; Del Peso, J; Del Prete, T; Delgove, D; Deliot, F; Delitzsch, C M; Deliyergiyev, M; Dell'Acqua, A; Dell'Asta, L; Dell'Orso, M; Della Pietra, M; Della Volpe, D; Delmastro, M; Delsart, P A; Deluca, C; DeMarco, D A; Demers, S; Demichev, M; Demilly, A; Denisov, S P; Derendarz, D; Derkaoui, J E; Derue, F; Dervan, P; Desch, K; Deterre, C; Deviveiros, P O; Dewhurst, A; Dhaliwal, S; Di Ciaccio, A; Di Ciaccio, L; Di Domenico, A; Di Donato, C; Di Girolamo, A; Di Girolamo, B; Di Mattia, A; Di Micco, B; Di Nardo, R; Di Simone, A; Di Sipio, R; Di Valentino, D; Diaconu, C; Diamond, M; Dias, F A; Diaz, M A; Diehl, E B; Dietrich, J; Diglio, S; Dimitrievska, A; Dingfelder, J; Dita, P; Dita, S; Dittus, F; Djama, F; Djobava, T; Djuvsland, J I; do Vale, M A B; Dobos, D; Dobre, M; Doglioni, C; Dohmae, T; Dolejsi, J; Dolezal, Z; Dolgoshein, B A; Donadelli, M; Donati, S; Dondero, P; Donini, J; Dopke, J; Doria, A; Dova, M T; Doyle, A T; Drechsler, E; Dris, M; Dubreuil, E; Duchovni, E; Duckeck, G; Ducu, O A; Duda, D; Dudarev, A; Duflot, L; Duguid, L; Dührssen, M; Dunford, M; Duran Yildiz, H; Düren, M; Durglishvili, A; Duschinger, D; Dyndal, M; Eckardt, C; Ecker, K M; Edgar, R C; Edson, W; Edwards, N C; Ehrenfeld, W; Eifert, T; Eigen, G; Einsweiler, K; Ekelof, T; El Kacimi, M; Ellert, M; Elles, S; Ellinghaus, F; Elliot, A A; Ellis, N; Elmsheuser, J; Elsing, M; Emeliyanov, D; Enari, Y; Endner, O C; Endo, M; Erdmann, J; Ereditato, A; Ernis, G; Ernst, J; Ernst, M; Errede, S; Ertel, E; Escalier, M; Esch, H; Escobar, C; Esposito, B; Etienvre, A I; Etzion, E; Evans, H; Ezhilov, A; Fabbri, L; Facini, G; Fakhrutdinov, R M; Falciano, S; Falla, R J; Faltova, J; Fang, Y; Fanti, M; Farbin, A; Farilla, A; Farooque, T; Farrell, S; Farrington, S M; Farthouat, P; Fassi, F; Fassnacht, P; Fassouliotis, D; Faucci Giannelli, M; Favareto, A; Fayard, L; Federic, P; Fedin, O L; Fedorko, W; Feigl, S; Feligioni, L; Feng, C; Feng, E J; Feng, H; Fenyuk, A B; Feremenga, L; Fernandez Martinez, P; Fernandez Perez, S; Ferrando, J; Ferrari, A; Ferrari, P; Ferrari, R; Ferreira de Lima, D E; Ferrer, A; Ferrere, D; Ferretti, C; Ferretto Parodi, A; Fiascaris, M; Fiedler, F; Filipčič, A; Filipuzzi, M; Filthaut, F; Fincke-Keeler, M; Finelli, K D; Fiolhais, M C N; Fiorini, L; Firan, A; Fischer, A; Fischer, C; Fischer, J; Fisher, W C; Fitzgerald, E A; Flaschel, N; Fleck, I; Fleischmann, P; Fleischmann, S; Fletcher, G T; Fletcher, G; Fletcher, R R M; Flick, T; Floderus, A; Flores Castillo, L R; Flowerdew, M J; Formica, A; Forti, A; Fournier, D; Fox, H; Fracchia, S; Francavilla, P; Franchini, M; Francis, D; Franconi, L; Franklin, M; Frate, M; Fraternali, M; Freeborn, D; French, S T; Friedrich, F; Froidevaux, D; Frost, J A; Fukunaga, C; Fullana Torregrosa, E; Fulsom, B G; Fuster, J; Gabaldon, C; Gabizon, O; Gabrielli, A; Gabrielli, A; Gadatsch, S; Gadomski, S; Gagliardi, G; Gagnon, P; Galea, C; Galhardo, B; Gallas, E J; Gallop, B J; Gallus, P; Galster, G; Gan, K K; Gao, J; Gao, Y; Gao, Y S; Garay Walls, F M; Garberson, F; García, C; García Navarro, J E; Garcia-Sciveres, M; Gardner, R W; Garelli, N; Garonne, V; Gatti, C; Gaudiello, A; Gaudio, G; Gaur, B; Gauthier, L; Gauzzi, P; Gavrilenko, I L; Gay, C; Gaycken, G; Gazis, E N; Ge, P; Gecse, Z; Gee, C N P; Geerts, D A A; Geich-Gimbel, Ch; Geisler, M P; Gemme, C; Genest, M H; Gentile, S; George, M; George, S; Gerbaudo, D; Gershon, A; Ghasemi, S; Ghazlane, H; Giacobbe, B; Giagu, S; Giangiobbe, V; Giannetti, P; Gibbard, B; Gibson, S M; Gilchriese, M; Gillam, T P S; Gillberg, D; Gilles, G; Gingrich, D M; Giokaris, N; Giordani, M P; Giorgi, F M; Giorgi, F M; Giraud, P F; Giromini, P; Giugni, D; Giuliani, C; Giulini, M; Gjelsten, B K; Gkaitatzis, S; Gkialas, I; Gkougkousis, E L; Gladilin, L K; Glasman, C; Glatzer, J; Glaysher, P C F; Glazov, A; Goblirsch-Kolb, M; Goddard, J R; Godlewski, J; Goldfarb, S; Golling, T; Golubkov, D; Gomes, A; Gonçalo, R; Goncalves Pinto Firmino Da Costa, J; Gonella, L; González de la Hoz, S; Gonzalez Parra, G; Gonzalez-Sevilla, S; Goossens, L; Gorbounov, P A; Gordon, H A; Gorelov, I; Gorini, B; Gorini, E; Gorišek, A; Gornicki, E; Goshaw, A T; Gössling, C; Gostkin, M I; Goujdami, D; Goussiou, A G; Govender, N; Gozani, E; Grabas, H M X; Graber, L; Grabowska-Bold, I; Grafström, P; Grahn, K-J; Gramling, J; Gramstad, E; Grancagnolo, S; Grassi, V; Gratchev, V; Gray, H M; Graziani, E; Greenwood, Z D; Gregersen, K; Gregor, I M; Grenier, P; Griffiths, J; Grillo, A A; Grimm, K; Grinstein, S; Gris, Ph; Grivaz, J-F; Grohs, J P; Grohsjean, A; Gross, E; Grosse-Knetter, J; Grossi, G C; Grout, Z J; Guan, L; Guenther, J; Guescini, F; Guest, D; Gueta, O; Guido, E; Guillemin, T; Guindon, S; Gul, U; Gumpert, C; Guo, J; Guo, Y; Gupta, S; Gustavino, G; Gutierrez, P; Gutierrez Ortiz, N G; Gutschow, C; Guyot, C; Gwenlan, C; Gwilliam, C B; Haas, A; Haber, C; Hadavand, H K; Haddad, N; Haefner, P; Hageböck, S; Hajduk, Z; Hakobyan, H; Haleem, M; Haley, J; Hall, D; Halladjian, G; Hallewell, G D; Hamacher, K; Hamal, P; Hamano, K; Hamer, M; Hamilton, A; Hamity, G N; Hamnett, P G; Han, L; Hanagaki, K; Hanawa, K; Hance, M; Hanke, P; Hanna, R; Hansen, J B; Hansen, J D; Hansen, M C; Hansen, P H; Hara, K; Hard, A S; Harenberg, T; Hariri, F; Harkusha, S; Harrington, R D; Harrison, P F; Hartjes, F; Hasegawa, M; Hasegawa, S; Hasegawa, Y; Hasib, A; Hassani, S; Haug, S; Hauser, R; Hauswald, L; Havranek, M; Hawkes, C M; Hawkings, R J; Hawkins, A D; Hayashi, T; Hayden, D; Hays, C P; Hays, J M; Hayward, H S; Haywood, S J; Head, S J; Heck, T; Hedberg, V; Heelan, L; Heim, S; Heim, T; Heinemann, B; Heinrich, L; Hejbal, J; Helary, L; Hellman, S; Hellmich, D; Helsens, C; Henderson, J; Henderson, R C W; Heng, Y; Hengler, C; Henrichs, A; Henriques Correia, A M; Henrot-Versille, S; Herbert, G H; Hernández Jiménez, Y; Herrberg-Schubert, R; Herten, G; Hertenberger, R; Hervas, L; Hesketh, G G; Hessey, N P; Hetherly, J W; Hickling, R; Higón-Rodriguez, E; Hill, E; Hill, J C; Hiller, K H; Hillier, S J; Hinchliffe, I; Hines, E; Hinman, R R; Hirose, M; Hirschbuehl, D; Hobbs, J; Hod, N; Hodgkinson, M C; Hodgson, P; Hoecker, A; Hoeferkamp, M R; Hoenig, F; Hohlfeld, M; Hohn, D; Holmes, T R; Homann, M; Hong, T M; Hooft van Huysduynen, L; Hopkins, W H; Horii, Y; Horton, A J; Hostachy, J-Y; Hou, S; Hoummada, A; Howard, J; Howarth, J; Hrabovsky, M; Hristova, I; Hrivnac, J; Hryn'ova, T; Hrynevich, A; Hsu, C; Hsu, P J; Hsu, S-C; Hu, D; Hu, Q; Hu, X; Huang, Y; Hubacek, Z; Hubaut, F; Huegging, F; Huffman, T B; Hughes, E W; Hughes, G; Huhtinen, M; Hülsing, T A; Huseynov, N; Huston, J; Huth, J; Iacobucci, G; Iakovidis, G; Ibragimov, I; Iconomidou-Fayard, L; Ideal, E; Idrissi, Z; Iengo, P; Igonkina, O; Iizawa, T; Ikegami, Y; Ikematsu, K; Ikeno, M; Ilchenko, Y; Iliadis, D; Ilic, N; Ince, T; Introzzi, G; Ioannou, P; Iodice, M; Iordanidou, K; Ippolito, V; Irles Quiles, A; Isaksson, C; Ishino, M; Ishitsuka, M; Ishmukhametov, R; Issever, C; Istin, S; Iturbe Ponce, J M; Iuppa, R; Ivarsson, J; Iwanski, W; Iwasaki, H; Izen, J M; Izzo, V; Jabbar, S; Jackson, B; Jackson, M; Jackson, P; Jaekel, M R; Jain, V; Jakobs, K; Jakobsen, S; Jakoubek, T; Jakubek, J; Jamin, D O; Jana, D K; Jansen, E; Jansky, R; Janssen, J; Janus, M; Jarlskog, G; Javadov, N; Javůrek, T; Jeanty, L; Jejelava, J; Jeng, G-Y; Jennens, D; Jenni, P; Jentzsch, J; Jeske, C; Jézéquel, S; Ji, H; Jia, J; Jiang, Y; Jiggins, S; Jimenez Pena, J; Jin, S; Jinaru, A; Jinnouchi, O; Joergensen, M D; Johansson, P; Johns, K A; Jon-And, K; Jones, G; Jones, R W L; Jones, T J; Jongmanns, J; Jorge, P M; Joshi, K D; Jovicevic, J; Ju, X; Jung, C A; Jussel, P; Juste Rozas, A; Kaci, M; Kaczmarska, A; Kado, M; Kagan, H; Kagan, M; Kahn, S J; Kajomovitz, E; Kalderon, C W; Kama, S; Kamenshchikov, A; Kanaya, N; Kaneti, S; Kantserov, V A; Kanzaki, J; Kaplan, B; Kaplan, L S; Kapliy, A; Kar, D; Karakostas, K; Karamaoun, A; Karastathis, N; Kareem, M J; Karnevskiy, M; Karpov, S N; Karpova, Z M; Karthik, K; Kartvelishvili, V; Karyukhin, A N; Kashif, L; Kass, R D; Kastanas, A; Kataoka, Y; Katre, A; Katzy, J; Kawagoe, K; Kawamoto, T; Kawamura, G; Kazama, S; Kazanin, V F; Kazarinov, M Y; Keeler, R; Kehoe, R; Keller, J S; Kempster, J J; Keoshkerian, H; Kepka, O; Kerševan, B P; Kersten, S; Keyes, R A; Khalil-Zada, F; Khandanyan, H; Khanov, A; Kharlamov, A G; Khoo, T J; Khovanskiy, V; Khramov, E; Khubua, J; Kim, H Y; Kim, H; Kim, S H; Kim, Y; Kimura, N; Kind, O M; King, B T; King, M; King, S B; Kirk, J; Kiryunin, A E; Kishimoto, T; Kisielewska, D; Kiss, F; Kiuchi, K; Kivernyk, O; Kladiva, E; Klein, M H; Klein, M; Klein, U; Kleinknecht, K; Klimek, P; Klimentov, A; Klingenberg, R; Klinger, J A; Klioutchnikova, T; Kluge, E-E; Kluit, P; Kluth, S; Knapik, J; Kneringer, E; Knoops, E B F G; Knue, A; Kobayashi, A; Kobayashi, D; Kobayashi, T; Kobel, M; Kocian, M; Kodys, P; Koffas, T; Koffeman, E; Kogan, L A; Kohlmann, S; Kohout, Z; Kohriki, T; Koi, T; Kolanoski, H; Koletsou, I; Komar, A A; Komori, Y; Kondo, T; Kondrashova, N; Köneke, K; König, A C; Kono, T; Konoplich, R; Konstantinidis, N; Kopeliansky, R; Koperny, S; Köpke, L; Kopp, A K; Korcyl, K; Kordas, K; Korn, A; Korol, A A; Korolkov, I; Korolkova, E V; Kortner, O; Kortner, S; Kosek, T; Kostyukhin, V V; Kotov, V M; Kotwal, A; Kourkoumeli-Charalampidi, A; Kourkoumelis, C; Kouskoura, V; Koutsman, A; Kowalewski, R; Kowalski, T Z; Kozanecki, W; Kozhin, A S; Kramarenko, V A; Kramberger, G; Krasnopevtsev, D; Krasny, M W; Krasznahorkay, A; Kraus, J K; Kravchenko, A; Kreiss, S; Kretz, M; Kretzschmar, J; Kreutzfeldt, K; Krieger, P; Krizka, K; Kroeninger, K; Kroha, H; Kroll, J; Kroseberg, J; Krstic, J; Kruchonak, U; Krüger, H; Krumnack, N; Krumshteyn, Z V; Kruse, A; Kruse, M C; Kruskal, M; Kubota, T; Kucuk, H; Kuday, S; Kuehn, S; Kugel, A; Kuger, F; Kuhl, A; Kuhl, T; Kukhtin, V; Kulchitsky, Y; Kuleshov, S; Kuna, M; Kunigo, T; Kupco, A; Kurashige, H; Kurochkin, Y A; Kus, V; Kuwertz, E S; Kuze, M; Kvita, J; Kwan, T; Kyriazopoulos, D; La Rosa, A; La Rosa Navarro, J L; La Rotonda, L; Lacasta, C; Lacava, F; Lacey, J; Lacker, H; Lacour, D; Lacuesta, V R; Ladygin, E; Lafaye, R; Laforge, B; Lagouri, T; Lai, S; Lambourne, L; Lammers, S; Lampen, C L; Lampl, W; Lançon, E; Landgraf, U; Landon, M P J; Lang, V S; Lange, J C; Lankford, A J; Lanni, F; Lantzsch, K; Lanza, A; Laplace, S; Lapoire, C; Laporte, J F; Lari, T; Lasagni Manghi, F; Lassnig, M; Laurelli, P; Lavrijsen, W; Law, A T; Laycock, P; Lazovich, T; Le Dortz, O; Le Guirriec, E; Le Menedeu, E; LeBlanc, M; LeCompte, T; Ledroit-Guillon, F; Lee, C A; Lee, S C; Lee, L; Lefebvre, G; Lefebvre, M; Legger, F; Leggett, C; Lehan, A; Lehmann Miotto, G; Lei, X; Leight, W A; Leisos, A; Leister, A G; Leite, M A L; Leitner, R; Lellouch, D; Lemmer, B; Leney, K J C; Lenz, T; Lenzi, B; Leone, R; Leone, S; Leonidopoulos, C; Leontsinis, S; Leroy, C; Lester, C G; Levchenko, M; Levêque, J; Levin, D; Levinson, L J; Levy, M; Lewis, A; Leyko, A M; Leyton, M; Li, B; Li, H; Li, H L; Li, L; Li, L; Li, S; Li, Y; Liang, Z; Liao, H; Liberti, B; Liblong, A; Lichard, P; Lie, K; Liebal, J; Liebig, W; Limbach, C; Limosani, A; Lin, S C; Lin, T H; Linde, F; Lindquist, B E; Linnemann, J T; Lipeles, E; Lipniacka, A; Lisovyi, M; Liss, T M; Lissauer, D; Lister, A; Litke, A M; Liu, B; Liu, D; Liu, H; Liu, J; Liu, J B; Liu, K; Liu, L; Liu, M; Liu, M; Liu, Y; Livan, M; Lleres, A; Llorente Merino, J; Lloyd, S L; Lo Sterzo, F; Lobodzinska, E; Loch, P; Lockman, W S; Loebinger, F K; Loevschall-Jensen, A E; Loginov, A; Lohse, T; Lohwasser, K; Lokajicek, M; Long, B A; Long, J D; Long, R E; Looper, K A; Lopes, L; Lopez Mateos, D; Lopez Paredes, B; Lopez Paz, I; Lorenz, J; Lorenzo Martinez, N; Losada, M; Loscutoff, P; Lösel, P J; Lou, X; Lounis, A; Love, J; Love, P A; Lu, N; Lubatti, H J; Luci, C; Lucotte, A; Luehring, F; Lukas, W; Luminari, L; Lundberg, O; Lund-Jensen, B; Lynn, D; Lysak, R; Lytken, E; Ma, H; Ma, L L; Maccarrone, G; Macchiolo, A; Macdonald, C M; Machado Miguens, J; Macina, D; Madaffari, D; Madar, R; Maddocks, H J; Mader, W F; Madsen, A; Maeland, S; Maeno, T; Maevskiy, A; Magradze, E; Mahboubi, K; Mahlstedt, J; Maiani, C; Maidantchik, C; Maier, A A; Maier, T; Maio, A; Majewski, S; Makida, Y; Makovec, N; Malaescu, B; Malecki, Pa; Maleev, V P; Malek, F; Mallik, U; Malon, D; Malone, C; Maltezos, S; Malyshev, V M; Malyukov, S; Mamuzic, J; Mancini, G; Mandelli, B; Mandelli, L; Mandić, I; Mandrysch, R; Maneira, J; Manfredini, A; Manhaes de Andrade Filho, L; Manjarres Ramos, J; Mann, A; Manning, P M; Manousakis-Katsikakis, A; Mansoulie, B; Mantifel, R; Mantoani, M; Mapelli, L; March, L; Marchiori, G; Marcisovsky, M; Marino, C P; Marjanovic, M; Marley, D E; Marroquim, F; Marsden, S P; Marshall, Z; Marti, L F; Marti-Garcia, S; Martin, B; Martin, T A; Martin, V J; Martin Dit Latour, B; Martinez, M; Martin-Haugh, S; Martoiu, V S; Martyniuk, A C; Marx, M; Marzano, F; Marzin, A; Masetti, L; Mashimo, T; Mashinistov, R; Masik, J; Maslennikov, A L; Massa, I; Massa, L; Massol, N; Mastrandrea, P; Mastroberardino, A; Masubuchi, T; Mättig, P; Mattmann, J; Maurer, J; Maxfield, S J; Maximov, D A; Mazini, R; Mazza, S M; Mazzaferro, L; Mc Goldrick, G; Mc Kee, S P; McCarn, A; McCarthy, R L; McCarthy, T G; McCubbin, N A; McFarlane, K W; Mcfayden, J A; Mchedlidze, G; McMahon, S J; McPherson, R A; Medinnis, M; Meehan, S; Mehlhase, S; Mehta, A; Meier, K; Meineck, C; Meirose, B; Mellado Garcia, B R; Meloni, F; Mengarelli, A; Menke, S; Meoni, E; Mercurio, K M; Mergelmeyer, S; Mermod, P; Merola, L; Meroni, C; Merritt, F S; Messina, A; Metcalfe, J; Mete, A S; Meyer, C; Meyer, C; Meyer, J-P; Meyer, J; Middleton, R P; Miglioranzi, S; Mijović, L; Mikenberg, G; Mikestikova, M; Mikuž, M; Milesi, M; Milic, A; Miller, D W; Mills, C; Milov, A; Milstead, D A; Minaenko, A A; Minami, Y; Minashvili, I A; Mincer, A I; Mindur, B; Mineev, M; Ming, Y; Mir, L M; Mitani, T; Mitrevski, J; Mitsou, V A; Miucci, A; Miyagawa, P S; Mjörnmark, J U; Moa, T; Mochizuki, K; Mohapatra, S; Mohr, W; Molander, S; Moles-Valls, R; Mönig, K; Monini, C; Monk, J; Monnier, E; Montejo Berlingen, J; Monticelli, F; Monzani, S; Moore, R W; Morange, N; Moreno, D; Moreno Llácer, M; Morettini, P; Morgenstern, M; Morii, M; Morinaga, M; Morisbak, V; Moritz, S; Morley, A K; Mornacchi, G; Morris, J D; Mortensen, S S; Morton, A; Morvaj, L; Mosidze, M; Moss, J; Motohashi, K; Mount, R; Mountricha, E; Mouraviev, S V; Moyse, E J W; Muanza, S; Mudd, R D; Mueller, F; Mueller, J; Mueller, R S P; Mueller, T; Muenstermann, D; Mullen, P; Mullier, G A; Murillo Quijada, J A; Murray, W J; Musheghyan, H; Musto, E; Myagkov, A G; Myska, M; Nackenhorst, O; Nadal, J; Nagai, K; Nagai, R; Nagai, Y; Nagano, K; Nagarkar, A; Nagasaka, Y; Nagata, K; Nagel, M; Nagy, E; Nairz, A M; Nakahama, Y; Nakamura, K; Nakamura, T; Nakano, I; Namasivayam, H; Naranjo Garcia, R F; Narayan, R; Naumann, T; Navarro, G; Nayyar, R; Neal, H A; Nechaeva, P Yu; Neep, T J; Nef, P D; Negri, A; Negrini, M; Nektarijevic, S; Nellist, C; Nelson, A; Nemecek, S; Nemethy, P; Nepomuceno, A A; Nessi, M; Neubauer, M S; Neumann, M; Neves, R M; Nevski, P; Newman, P R; Nguyen, D H; Nickerson, R B; Nicolaidou, R; Nicquevert, B; Nielsen, J; Nikiforou, N; Nikiforov, A; Nikolaenko, V; Nikolic-Audit, I; Nikolopoulos, K; Nilsen, J K; Nilsson, P; Ninomiya, Y; Nisati, A; Nisius, R; Nobe, T; Nomachi, M; Nomidis, I; Nooney, T; Norberg, S; Nordberg, M; Novgorodova, O; Nowak, S; Nozaki, M; Nozka, L; Ntekas, K; Nunes Hanninger, G; Nunnemann, T; Nurse, E; Nuti, F; O'Brien, B J; O'grady, F; O'Neil, D C; O'Shea, V; Oakham, F G; Oberlack, H; Obermann, T; Ocariz, J; Ochi, A; Ochoa, I; Ochoa-Ricoux, J P; Oda, S; Odaka, S; Ogren, H; Oh, A; Oh, S H; Ohm, C C; Ohman, H; Oide, H; Okamura, W; Okawa, H; Okumura, Y; Okuyama, T; Olariu, A; Olivares Pino, S A; Oliveira Damazio, D; Oliver Garcia, E; Olszewski, A; Olszowska, J; Onofre, A; Onyisi, P U E; Oram, C J; Oreglia, M J; Oren, Y; Orestano, D; Orlando, N; Oropeza Barrera, C; Orr, R S; Osculati, B; Ospanov, R; Otero Y Garzon, G; Otono, H; Ouchrif, M; Ouellette, E A; Ould-Saada, F; Ouraou, A; Oussoren, K P; Ouyang, Q; Ovcharova, A; Owen, M; Owen, R E; Ozcan, V E; Ozturk, N; Pachal, K; Pacheco Pages, A; Padilla Aranda, C; Pagáčová, M; Pagan Griso, S; Paganis, E; Paige, F; Pais, P; Pajchel, K; Palacino, G; Palestini, S; Palka, M; Pallin, D; Palma, A; Pan, Y B; Panagiotopoulou, E; Pandini, C E; Panduro Vazquez, J G; Pani, P; Panitkin, S; Pantea, D; Paolozzi, L; Papadopoulou, Th D; Papageorgiou, K; Paramonov, A; Paredes Hernandez, D; Parker, M A; Parker, K A; Parodi, F; Parsons, J A; Parzefall, U; Pasqualucci, E; Passaggio, S; Pastore, F; Pastore, Fr; Pásztor, G; Pataraia, S; Patel, N D; Pater, J R; Pauly, T; Pearce, J; Pearson, B; Pedersen, L E; Pedersen, M; Pedraza Lopez, S; Pedro, R; Peleganchuk, S V; Pelikan, D; Penc, O; Peng, C; Peng, H; Penning, B; Penwell, J; Perepelitsa, D V; Perez Codina, E; Pérez García-Estañ, M T; Perini, L; Pernegger, H; Perrella, S; Peschke, R; Peshekhonov, V D; Peters, K; Peters, R F Y; Petersen, B A; Petersen, T C; Petit, E; Petridis, A; Petridou, C; Petrolo, E; Petrucci, F; Pettersson, N E; Pezoa, R; Phillips, P W; Piacquadio, G; Pianori, E; Picazio, A; Piccaro, E; Piccinini, M; Pickering, M A; Piegaia, R; Pignotti, D T; Pilcher, J E; Pilkington, A D; Pina, J; Pinamonti, M; Pinfold, J L; Pingel, A; Pinto, B; Pires, S; Pirumov, H; Pitt, M; Pizio, C; Plazak, L; Pleier, M-A; Pleskot, V; Plotnikova, E; Plucinski, P; Pluth, D; Poettgen, R; Poggioli, L; Pohl, D; Polesello, G; Poley, A; Policicchio, A; Polifka, R; Polini, A; Pollard, C S; Polychronakos, V; Pommès, K; Pontecorvo, L; Pope, B G; Popeneciu, G A; Popovic, D S; Poppleton, A; Pospisil, S; Potamianos, K; Potrap, I N; Potter, C J; Potter, C T; Poulard, G; Poveda, J; Pozdnyakov, V; Pralavorio, P; Pranko, A; Prasad, S; Prell, S; Price, D; Price, L E; Primavera, M; Prince, S; Proissl, M; Prokofiev, K; Prokoshin, F; Protopapadaki, E; Protopopescu, S; Proudfoot, J; Przybycien, M; Ptacek, E; Puddu, D; Pueschel, E; Puldon, D; Purohit, M; Puzo, P; Qian, J; Qin, G; Qin, Y; Quadt, A; Quarrie, D R; Quayle, W B; Queitsch-Maitland, M; Quilty, D; Raddum, S; Radeka, V; Radescu, V; Radhakrishnan, S K; Radloff, P; Rados, P; Ragusa, F; Rahal, G; Rajagopalan, S; Rammensee, M; Rangel-Smith, C; Rauscher, F; Rave, S; Ravenscroft, T; Raymond, M; Read, A L; Readioff, N P; Rebuzzi, D M; Redelbach, A; Redlinger, G; Reece, R; Reeves, K; Rehnisch, L; Reisin, H; Relich, M; Rembser, C; Ren, H; Renaud, A; Rescigno, M; Resconi, S; Rezanova, O L; Reznicek, P; Rezvani, R; Richter, R; Richter, S; Richter-Was, E; Ricken, O; Ridel, M; Rieck, P; Riegel, C J; Rieger, J; Rijssenbeek, M; Rimoldi, A; Rinaldi, L; Ristić, B; Ritsch, E; Riu, I; Rizatdinova, F; Rizvi, E; Robertson, S H; Robichaud-Veronneau, A; Robinson, D; Robinson, J E M; Robson, A; Roda, C; Roe, S; Røhne, O; Rolli, S; Romaniouk, A; Romano, M; Romano Saez, S M; Romero Adam, E; Rompotis, N; Ronzani, M; Roos, L; Ros, E; Rosati, S; Rosbach, K; Rose, P; Rosendahl, P L; Rosenthal, O; Rossetti, V; Rossi, E; Rossi, L P; Rosten, R; Rotaru, M; Roth, I; Rothberg, J; Rousseau, D; Royon, C R; Rozanov, A; Rozen, Y; Ruan, X; Rubbo, F; Rubinskiy, I; Rud, V I; Rudolph, C; Rudolph, M S; Rühr, F; Ruiz-Martinez, A; Rurikova, Z; Rusakovich, N A; Ruschke, A; Russell, H L; Rutherfoord, J P; Ruthmann, N; Ryabov, Y F; Rybar, M; Rybkin, G; Ryder, N C; Saavedra, A F; Sabato, G; Sacerdoti, S; Saddique, A; Sadrozinski, H F-W; Sadykov, R; Safai Tehrani, F; Saimpert, M; Sakamoto, H; Sakurai, Y; Salamanna, G; Salamon, A; Saleem, M; Salek, D; Sales De Bruin, P H; Salihagic, D; Salnikov, A; Salt, J; Salvatore, D; Salvatore, F; Salvucci, A; Salzburger, A; Sampsonidis, D; Sanchez, A; Sánchez, J; Sanchez Martinez, V; Sandaker, H; Sandbach, R L; Sander, H G; Sanders, M P; Sandhoff, M; Sandoval, C; Sandstroem, R; Sankey, D P C; Sannino, M; Sansoni, A; Santoni, C; Santonico, R; Santos, H; Santoyo Castillo, I; Sapp, K; Sapronov, A; Saraiva, J G; Sarrazin, B; Sasaki, O; Sasaki, Y; Sato, K; Sauvage, G; Sauvan, E; Savage, G; Savard, P; Sawyer, C; Sawyer, L; Saxon, J; Sbarra, C; Sbrizzi, A; Scanlon, T; Scannicchio, D A; Scarcella, M; Scarfone, V; Schaarschmidt, J; Schacht, P; Schaefer, D; Schaefer, R; Schaeffer, J; Schaepe, S; Schaetzel, S; Schäfer, U; Schaffer, A C; Schaile, D; Schamberger, R D; Scharf, V; Schegelsky, V A; Scheirich, D; Schernau, M; Schiavi, C; Schillo, C; Schioppa, M; Schlenker, S; Schmidt, E; Schmieden, K; Schmitt, C; Schmitt, S; Schmitt, S; Schneider, B; Schnellbach, Y J; Schnoor, U; Schoeffel, L; Schoening, A; Schoenrock, B D; Schopf, E; Schorlemmer, A L S; Schott, M; Schouten, D; Schovancova, J; Schramm, S; Schreyer, M; Schroeder, C; Schuh, N; Schultens, M J; Schultz-Coulon, H-C; Schulz, H; Schumacher, M; Schumm, B A; Schune, Ph; Schwanenberger, C; Schwartzman, A; Schwarz, T A; Schwegler, Ph; Schweiger, H; Schwemling, Ph; Schwienhorst, R; Schwindling, J; Schwindt, T; Sciacca, F G; Scifo, E; Sciolla, G; Scuri, F; Scutti, F; Searcy, J; Sedov, G; Sedykh, E; Seema, P; Seidel, S C; Seiden, A; Seifert, F; Seixas, J M; Sekhniaidze, G; Sekhon, K; Sekula, S J; Seliverstov, D M; Semprini-Cesari, N; Serfon, C; Serin, L; Serkin, L; Serre, T; Sessa, M; Seuster, R; Severini, H; Sfiligoj, T; Sforza, F; Sfyrla, A; Shabalina, E; Shamim, M; Shan, L Y; Shang, R; Shank, J T; Shapiro, M; Shatalov, P B; Shaw, K; Shaw, S M; Shcherbakova, A; Shehu, C Y; Sherwood, P; Shi, L; Shimizu, S; Shimmin, C O; Shimojima, M; Shiyakova, M; Shmeleva, A; Shoaleh Saadi, D; Shochet, M J; Shojaii, S; Shrestha, S; Shulga, E; Shupe, M A; Shushkevich, S; Sicho, P; Sidebo, P E; Sidiropoulou, O; Sidorov, D; Sidoti, A; Siegert, F; Sijacki, Dj; Silva, J; Silver, Y; Silverstein, S B; Simak, V; Simard, O; Simic, Lj; Simion, S; Simioni, E; Simmons, B; Simon, D; Simoniello, R; Sinervo, P; Sinev, N B; Sioli, M; Siragusa, G; Sisakyan, A N; Sivoklokov, S Yu; Sjölin, J; Sjursen, T B; Skinner, M B; Skottowe, H P; Skubic, P; Slater, M; Slavicek, T; Slawinska, M; Sliwa, K; Smakhtin, V; Smart, B H; Smestad, L; Smirnov, S Yu; Smirnov, Y; Smirnova, L N; Smirnova, O; Smith, M N K; Smith, R W; Smizanska, M; Smolek, K; Snesarev, A A; Snidero, G; Snyder, S; Sobie, R; Socher, F; Soffer, A; Soh, D A; Solans, C A; Solar, M; Solc, J; Soldatov, E Yu; Soldevila, U; Solodkov, A A; Soloshenko, A; Solovyanov, O V; Solovyev, V; Sommer, P; Song, H Y; Soni, N; Sood, A; Sopczak, A; Sopko, B; Sopko, V; Sorin, V; Sosa, D; Sosebee, M; Sotiropoulou, C L; Soualah, R; Soukharev, A M; South, D; Sowden, B C; Spagnolo, S; Spalla, M; Spanò, F; Spearman, W R; Sperlich, D; Spettel, F; Spighi, R; Spigo, G; Spiller, L A; Spousta, M; Spreitzer, T; St Denis, R D; Staerz, S; Stahlman, J; Stamen, R; Stamm, S; Stanecka, E; Stanescu, C; Stanescu-Bellu, M; Stanitzki, M M; Stapnes, S; Starchenko, E A; Stark, J; Staroba, P; Starovoitov, P; Staszewski, R; Stavina, P; Steinberg, P; Stelzer, B; Stelzer, H J; Stelzer-Chilton, O; Stenzel, H; Stewart, G A; Stillings, J A; Stockton, M C; Stoebe, M; Stoicea, G; Stolte, P; Stonjek, S; Stradling, A R; Straessner, A; Stramaglia, M E; Strandberg, J; Strandberg, S; Strandlie, A; Strauss, E; Strauss, M; Strizenec, P; Ströhmer, R; Strom, D M; Stroynowski, R; Strubig, A; Stucci, S A; Stugu, B; Styles, N A; Su, D; Su, J; Subramaniam, R; Succurro, A; Sugaya, Y; Suhr, C; Suk, M; Sulin, V V; Sultansoy, S; Sumida, T; Sun, S; Sun, X; Sundermann, J E; Suruliz, K; Susinno, G; Sutton, M R; Suzuki, S; Svatos, M; Swedish, S; Swiatlowski, M; Sykora, I; Sykora, T; Ta, D; Taccini, C; Tackmann, K; Taenzer, J; Taffard, A; Tafirout, R; Taiblum, N; Takai, H; Takashima, R; Takeda, H; Takeshita, T; Takubo, Y; Talby, M; Talyshev, A A; Tam, J Y C; Tan, K G; Tanaka, J; Tanaka, R; Tanaka, S; Tannenwald, B B; Tannoury, N; Tapprogge, S; Tarem, S; Tarrade, F; Tartarelli, G F; Tas, P; Tasevsky, M; Tashiro, T; Tassi, E; Tavares Delgado, A; Tayalati, Y; Taylor, F E; Taylor, G N; Taylor, W; Teischinger, F A; Teixeira Dias Castanheira, M; Teixeira-Dias, P; Temming, K K; Ten Kate, H; Teng, P K; Teoh, J J; Tepel, F; Terada, S; Terashi, K; Terron, J; Terzo, S; Testa, M; Teuscher, R J; Theveneaux-Pelzer, T; Thomas, J P; Thomas-Wilsker, J; Thompson, E N; Thompson, P D; Thompson, R J; Thompson, A S; Thomsen, L A; Thomson, E; Thomson, M; Thun, R P; Tibbetts, M J; Ticse Torres, R E; Tikhomirov, V O; Tikhonov, Yu A; Timoshenko, S; Tiouchichine, E; Tipton, P; Tisserant, S; Todome, K; Todorov, T; Todorova-Nova, S; Tojo, J; Tokár, S; Tokushuku, K; Tollefson, K; Tolley, E; Tomlinson, L; Tomoto, M; Tompkins, L; Toms, K; Torrence, E; Torres, H; Torró Pastor, E; Toth, J; Touchard, F; Tovey, D R; Trefzger, T; Tremblet, L; Tricoli, A; Trigger, I M; Trincaz-Duvoid, S; Tripiana, M F; Trischuk, W; Trocmé, B; Troncon, C; Trottier-McDonald, M; Trovatelli, M; True, P; Truong, L; Trzebinski, M; Trzupek, A; Tsarouchas, C; Tseng, J C-L; Tsiareshka, P V; Tsionou, D; Tsipolitis, G; Tsirintanis, N; Tsiskaridze, S; Tsiskaridze, V; Tskhadadze, E G; Tsukerman, I I; Tsulaia, V; Tsuno, S; Tsybychev, D; Tudorache, A; Tudorache, V; Tuna, A N; Tupputi, S A; Turchikhin, S; Turecek, D; Turra, R; Turvey, A J; Tuts, P M; Tykhonov, A; Tylmad, M; Tyndel, M; Ueda, I; Ueno, R; Ughetto, M; Ugland, M; Uhlenbrock, M; Ukegawa, F; Unal, G; Undrus, A; Unel, G; Ungaro, F C; Unno, Y; Unverdorben, C; Urban, J; Urquijo, P; Urrejola, P; Usai, G; Usanova, A; Vacavant, L; Vacek, V; Vachon, B; Valderanis, C; Valencic, N; Valentinetti, S; Valero, A; Valery, L; Valkar, S; Valladolid Gallego, E; Vallecorsa, S; Valls Ferrer, J A; Van Den Wollenberg, W; Van Der Deijl, P C; van der Geer, R; van der Graaf, H; Van Der Leeuw, R; van Eldik, N; van Gemmeren, P; Van Nieuwkoop, J; van Vulpen, I; van Woerden, M C; Vanadia, M; Vandelli, W; Vanguri, R; Vaniachine, A; Vannucci, F; Vardanyan, G; Vari, R; Varnes, E W; Varol, T; Varouchas, D; Vartapetian, A; Varvell, K E; Vazeille, F; Vazquez Schroeder, T; Veatch, J; Veloce, L M; Veloso, F; Velz, T; Veneziano, S; Ventura, A; Ventura, D; Venturi, M; Venturi, N; Venturini, A; Vercesi, V; Verducci, M; Verkerke, W; Vermeulen, J C; Vest, A; Vetterli, M C; Viazlo, O; Vichou, I; Vickey, T; Vickey Boeriu, O E; Viehhauser, G H A; Viel, S; Vigne, R; Villa, M; Villaplana Perez, M; Vilucchi, E; Vincter, M G; Vinogradov, V B; Vivarelli, I; Vives Vaque, F; Vlachos, S; Vladoiu, D; Vlasak, M; Vogel, M; Vokac, P; Volpi, G; Volpi, M; von der Schmitt, H; von Radziewski, H; von Toerne, E; Vorobel, V; Vorobev, K; Vos, M; Voss, R; Vossebeld, J H; Vranjes, N; Vranjes Milosavljevic, M; Vrba, V; Vreeswijk, M; Vuillermet, R; Vukotic, I; Vykydal, Z; Wagner, P; Wagner, W; Wahlberg, H; Wahrmund, S; Wakabayashi, J; Walder, J; Walker, R; Walkowiak, W; Wang, C; Wang, F; Wang, H; Wang, H; Wang, J; Wang, J; Wang, K; Wang, R; Wang, S M; Wang, T; Wang, T; Wang, X; Wanotayaroj, C; Warburton, A; Ward, C P; Wardrope, D R; Warsinsky, M; Washbrook, A; Wasicki, C; Watkins, P M; Watson, A T; Watson, I J; Watson, M F; Watts, G; Watts, S; Waugh, B M; Webb, S; Weber, M S; Weber, S W; Webster, J S; Weidberg, A R; Weinert, B; Weingarten, J; Weiser, C; Weits, H; Wells, P S; Wenaus, T; Wengler, T; Wenig, S; Wermes, N; Werner, M; Werner, P; Wessels, M; Wetter, J; Whalen, K; Wharton, A M; White, A; White, M J; White, R; White, S; Whiteson, D; Wickens, F J; Wiedenmann, W; Wielers, M; Wienemann, P; Wiglesworth, C; Wiik-Fuchs, L A M; Wildauer, A; Wilkens, H G; Williams, H H; Williams, S; Willis, C; Willocq, S; Wilson, A; Wilson, J A; Wingerter-Seez, I; Winklmeier, F; Winter, B T; Wittgen, M; Wittkowski, J; Wollstadt, S J; Wolter, M W; Wolters, H; Wosiek, B K; Wotschack, J; Woudstra, M J; Wozniak, K W; Wu, M; Wu, M; Wu, S L; Wu, X; Wu, Y; Wyatt, T R; Wynne, B M; Xella, S; Xu, D; Xu, L; Yabsley, B; Yacoob, S; Yakabe, R; Yamada, M; Yamaguchi, Y; Yamamoto, A; Yamamoto, S; Yamanaka, T; Yamauchi, K; Yamazaki, Y; Yan, Z; Yang, H; Yang, H; Yang, Y; Yao, W-M; Yasu, Y; Yatsenko, E; Yau Wong, K H; Ye, J; Ye, S; Yeletskikh, I; Yen, A L; Yildirim, E; Yorita, K; Yoshida, R; Yoshihara, K; Young, C; Young, C J S; Youssef, S; Yu, D R; Yu, J; Yu, J M; Yu, J; Yuan, L; Yurkewicz, A; Yusuff, I; Zabinski, B; Zaidan, R; Zaitsev, A M; Zalieckas, J; Zaman, A; Zambito, S; Zanello, L; Zanzi, D; Zeitnitz, C; Zeman, M; Zemla, A; Zengel, K; Zenin, O; Ženiš, T; Zerwas, D; Zhang, D; Zhang, F; Zhang, H; Zhang, J; Zhang, L; Zhang, R; Zhang, X; Zhang, Z; Zhao, X; Zhao, Y; Zhao, Z; Zhemchugov, A; Zhong, J; Zhou, B; Zhou, C; Zhou, L; Zhou, L; Zhou, N; Zhu, C G; Zhu, H; Zhu, J; Zhu, Y; Zhuang, X; Zhukov, K; Zibell, A; Zieminska, D; Zimine, N I; Zimmermann, C; Zimmermann, S; Zinonos, Z; Zinser, M; Ziolkowski, M; Živković, L; Zobernig, G; Zoccoli, A; Zur Nedden, M; Zurzolo, G; Zwalinski, L

Studies of the spin, parity and tensor couplings of the Higgs boson in the [Formula: see text], [Formula: see text] and [Formula: see text] decay processes at the LHC are presented. The investigations are based on [Formula: see text] of pp collision data collected by the ATLAS experiment at [Formula: see text] TeV and [Formula: see text] TeV. The Standard Model (SM) Higgs boson hypothesis, corresponding to the quantum numbers [Formula: see text], is tested against several alternative spin scenarios, including non-SM spin-0 and spin-2 models with universal and non-universal couplings to fermions and vector bosons. All tested alternative models are excluded in favour of the SM Higgs boson hypothesis at more than 99.9 % confidence level. Using the [Formula: see text] and [Formula: see text] decays, the tensor structure of the interaction between the spin-0 boson and the SM vector bosons is also investigated. The observed distributions of variables sensitive to the non-SM tensor couplings are compatible with the SM predictions and constraints on the non-SM couplings are derived.

Spin-dependent excitation of plasma modes in non-neutral ion plasmas

NASA Astrophysics Data System (ADS)

Sawyer, Brian C.; Britton, Joe W.; Bollinger, John J.

2011-10-01

We report on a new technique for exciting and sensitively detecting plasma modes in small, cold non-neutral ion plasmas. The technique uses an optical dipole force generated from laser beams to excite plasma modes. By making the force spin- dependent (i.e. depend on the internal state of the atomic ion) very small mode excitations (<100 nm) can be detected through spin-motion entanglement. Even when the optical dipole force is homogeneous throughout the plasma, short wavelength modes on the order of the interparticle spacing can in principle be excited and detected through the spin dependence of the force. We use this technique to study the drumhead modes of single plane triangular arrays of a few hundred Be+ ions. Spin-dependent mode excitation is interesting in this system because it provides a means of engineering an Ising interaction on a 2-D triangular lattice. For the case of an anti-ferromagnetic interaction, this system exhibits spin frustration on a scale that is at present computationally intractable. Work supported by the DARPA OLE program and NIST.

Flux Noise due to Spins in SQUIDs

NASA Astrophysics Data System (ADS)

LaForest, Stephanie

Superconducting Quantum Interference Devices (SQUIDs) are currently being used as flux qubits and read-out detectors in a variety of solid-state quantum computer architectures. The main limitation of SQUID qubits is that they have a coherence time of the order of 10 micros, due to the presence of intrinsic flux noise that is not yet fully understood. The origin of flux noise is currently believed to be related to spin impurities present in the materials and interfaces that form the device. Here we present a novel numerical method that enables calculations of the flux produced by spin impurities even when they are located quite close to the SQUID wire. We show that the SQUID will be particularly sensitive to spins located at its wire edges, generating flux shifts of up to 4 nano flux quanta, much higher than previous calculations based on the software package FastHenry. This shows that spin impurities in a particular region along the wire's surface play a much more important role in producing flux noise than other spin impurities located elsewhere in the device.

Tunnel based spin injection devices for semiconductor spintronics

NASA Astrophysics Data System (ADS)

Jiang, Xin

This dissertation summarizes the work on spin-dependent electron transport and spin injection in tunnel based spintronic devices. In particular, it focuses on a novel three terminal hot electron device combining ferromagnetic metals and semiconductors---the magnetic tunnel transistor (MTT). The MTT has extremely high magnetic field sensitivity and is a useful tool to explore spin-dependent electron transport in metals, semiconductors, and at their interfaces over a wide energy range. In Chap. 1, the basic concept and fabrication of the MTT are discussed. Two types of MTTs, with ferromagnetic single and spin-valve base layers, respectively, are introduced and compared. In the following chapters, the transport properties of the MTT are discussed in detail, including the spin-dependent hot electron attenuation lengths in CoFe and NiFe thin films on GaAs (Chap. 2), the bias voltage dependence of the magneto-current (Chap. 3), the giant magneto-current effect in MTTs with a spin-valve base (Chap. 4), and the influence of non-magnetic seed layers on magneto-electronic properties of MTTs with a Si collector (Chap. 5). Chap. 6 concentrates on electrical injection of spin-polarized electrons into semiconductors, which is an essential ingredient in semiconductor spintronics. Two types of spin injectors are discussed: an MTT injector and a CoFe/MgO tunnel injector. The spin polarization of the injected electron current is detected optically by measuring the circular polarization of electroluminescence from a quantum well light emitting diode. Using an MTT injector a spin polarization of ˜10% is found for injection electron energy of ˜2 eV at 1.4K. This moderate spin polarization is most likely limited by significant electron spin relaxation at high energy. Much higher spin injection efficiency is obtained by using a CoFe/MgO tunnel injector with spin polarization values of ˜50% at 100K. The temperature and bias dependence of the electroluminescence polarization provides insight into spin relaxation mechanisms within the semiconductor heterostructure.

Quantum computing with acceptor spins in silicon.

PubMed

Salfi, Joe; Tong, Mengyang; Rogge, Sven; Culcer, Dimitrie

2016-06-17

The states of a boron acceptor near a Si/SiO2 interface, which bind two low-energy Kramers pairs, have exceptional properties for encoding quantum information and, with the aid of strain, both heavy hole and light hole-based spin qubits can be designed. Whereas a light-hole spin qubit was introduced recently (arXiv:1508.04259), here we present analytical and numerical results proving that a heavy-hole spin qubit can be reliably initialised, rotated and entangled by electrical means alone. This is due to strong Rashba-like spin-orbit interaction terms enabled by the interface inversion asymmetry. Single qubit rotations rely on electric-dipole spin resonance (EDSR), which is strongly enhanced by interface-induced spin-orbit terms. Entanglement can be accomplished by Coulomb exchange, coupling to a resonator, or spin-orbit induced dipole-dipole interactions. By analysing the qubit sensitivity to charge noise, we demonstrate that interface-induced spin-orbit terms are responsible for sweet spots in the dephasing time [Formula: see text] as a function of the top gate electric field, which are close to maxima in the EDSR strength, where the EDSR gate has high fidelity. We show that both qubits can be described using the same starting Hamiltonian, and by comparing their properties we show that the complex interplay of bulk and interface-induced spin-orbit terms allows a high degree of electrical control and makes acceptors potential candidates for scalable quantum computation in Si.

Rose bengal-grafted biodegradable microcapsules: singlet-oxygen generation and cancer-cell incapacitation.

PubMed

Wang, Xiao-Lei; Zeng, Yu; Zheng, Yan-Zhen; Chen, Jian-Feng; Tao, Xia; Wang, Ling-Xuan; Teng, Yan

2011-09-26

Rose bengal-grafted chitosan (RB-CHI), synthesized through dehydration between amino and carboxyl functional groups under mild conditions, was coated onto the outer layer of preformed biodegradable microcapsules consisting of sodium alginate and chitosan. The fabricated photosensitive microcapsules were characterized by optical microscopy, scanning electron microscopy, and confocal laser scanning microscopy. The assembled materials maintained intact spherical morphology and thus showed good ability to form thin films. Electron spin resonance spectroscopy allowed direct observation of the generation of singlet oxygen ((1)O(2)) from photosensitive microcapsules under light excitation at about 545 nm. Furthermore, with increasing light radiation, the content of (1)O(2) increased, as detected by a chemical probe. In vitro cellular toxicity assays showed that RB-CHI-coated photosensitive microcapsules exhibit good biocompatibility in darkness and high cytotoxicity after irradiation, and could provide new photoresponsive drug-delivery vehicles. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Role of semiconductivity and ion transport in the electrical conduction of melanin

PubMed Central

Mostert, Albertus B.; Powell, Benjamin J.; Pratt, Francis L.; Hanson, Graeme R.; Sarna, Tadeusz; Gentle, Ian R.; Meredith, Paul

2012-01-01

Melanins are pigmentary macromolecules found throughout the biosphere that, in the 1970s, were discovered to conduct electricity and display bistable switching. Since then, it has been widely believed that melanins are naturally occurring amorphous organic semiconductors. Here, we report electrical conductivity, muon spin relaxation, and electron paramagnetic resonance measurements of melanin as the environmental humidity is varied. We show that hydration of melanin shifts the comproportionation equilibrium so as to dope electrons and protons into the system. This equilibrium defines the relative proportions of hydroxyquinone, semiquinone, and quinone species in the macromolecule. As such, the mechanism explains why melanin at neutral pH only conducts when “wet” and suggests that both carriers play a role in the conductivity. Understanding that melanin is an electronic-ionic hybrid conductor rather than an amorphous organic semiconductor opens exciting possibilities for bioelectronic applications such as ion-to-electron transduction given its biocompatibility. PMID:22615355

Galactic nuclei evolution with spinning black holes: method and implementation

NASA Astrophysics Data System (ADS)

Fiacconi, Davide; Sijacki, Debora; Pringle, J. E.

2018-04-01

Supermassive black holes at the centre of galactic nuclei mostly grow in mass through gas accretion over cosmic time. This process also modifies the angular momentum (or spin) of black holes, both in magnitude and in orientation. Despite being often neglected in galaxy formation simulations, spin plays a crucial role in modulating accretion power, driving jet feedback, and determining recoil velocity of coalescing black hole binaries. We present a new accretion model for the moving-mesh code AREPO that incorporates (i) mass accretion through a thin α-disc, and (ii) spin evolution through the Bardeen-Petterson effect. We use a diverse suite of idealised simulations to explore the physical connection between spin evolution and larger scale environment. We find that black holes with mass ≲ 107 M⊙ experience quick alignment with the accretion disc. This favours prolonged phases of spin-up, and the spin direction evolves according to the gas inflow on timescales as short as ≲ 100 Myr, which might explain the observed jet direction distribution in Seyfert galaxies. Heavier black holes (≳ 108 M⊙) are instead more sensitive to the local gas kinematic. Here we find a wider distribution in spin magnitudes: spin-ups are favoured if gas inflow maintains a preferential direction, and spin-downs occur for nearly isotropic infall, while the spin direction does not change much over short timescales ˜100 Myr. We therefore conclude that supermassive black holes with masses ≳ 5 × 108 M⊙ may be the ideal testbed to determine the main mode of black hole fuelling over cosmic time.

Elliptical polarization of near-resonant linearly polarized probe light in optically pumped alkali metal vapor

PubMed Central

Li, Yingying; Wang, Zhiguo; Jin, Shilong; Yuan, Jie; Luo, Hui

2017-01-01

Optically pumped alkali metal atoms currently provide a sensitive solution for magnetic microscopic measurements. As the most practicable plan, Faraday rotation of linearly polarized light is extensively used in spin polarization measurements of alkali metal atoms. In some cases, near-resonant Faraday rotation is applied to improve the sensitivity. However, the near-resonant linearly polarized probe light is elliptically polarized after passing through optically pumped alkali metal vapor. The ellipticity of transmitted near-resonant probe light is numerically calculated and experimentally measured. In addition, we also analyze the negative impact of elliptical polarization on Faraday rotation measurements. From our theoretical estimate and experimental results, the elliptical polarization forms an inevitable error in spin polarization measurements. PMID:28216649

Design of a 15N Molecular Unit to Achieve Long Retention of Hyperpolarized Spin State

NASA Astrophysics Data System (ADS)

Nonaka, Hiroshi; Hirano, Masashi; Imakura, Yuki; Takakusagi, Yoichi; Ichikawa, Kazuhiro; Sando, Shinsuke

2017-01-01

Nuclear hyperpolarization is a phenomenon that can be used to improve the sensitivity of magnetic resonance molecular sensors. However, such sensors typically suffer from short hyperpolarization lifetime. Herein we report that [15N, D14]trimethylphenylammonium (TMPA) has a remarkably long spin-lattice relaxation time (1128 s, 14.1 T, 30 °C, D2O) on its 15N nuclei and achieves a long retention of the hyperpolarized state. [15N, D14]TMPA-based hyperpolarized sensor for carboxylesterase allowed the highly sensitive analysis of enzymatic reaction by 15N NMR for over 40 min in phophate-buffered saline (H2O, pH 7.4, 37 °C).

Magnetic Resonance with Squeezed Microwaves

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bienfait, A.; Campagne-Ibarcq, P.; Kiilerich, A. H.

2017-10-17

Vacuum fluctuations of the electromagnetic field set a fundamental limit to the sensitivity of a variety of measurements, including magnetic resonance spectroscopy. We report the use of squeezed microwave fields, which are engineered quantum states of light for which fluctuations in one field quadrature are reduced below the vacuum level, to enhance the detection sensitivity of an ensemble of electronic spins at millikelvin temperatures. By shining a squeezed vacuum state on the input port of a microwave resonator containing the spins, we obtain a 1.2-dB noise reduction at the spectrometer output compared to the case of a vacuum input. Thismore » result constitutes a proof of principle of the application of quantum metrology to magnetic resonance spectroscopy.« less

Reversible interactions with para-hydrogen enhance NMR sensitivity by polarization transfer.

PubMed

Adams, Ralph W; Aguilar, Juan A; Atkinson, Kevin D; Cowley, Michael J; Elliott, Paul I P; Duckett, Simon B; Green, Gary G R; Khazal, Iman G; López-Serrano, Joaquín; Williamson, David C

2009-03-27

The sensitivity of both nuclear magnetic resonance spectroscopy and magnetic resonance imaging is very low because the detected signal strength depends on the small population difference between spin states even in high magnetic fields. Hyperpolarization methods can be used to increase this difference and thereby enhance signal strength. This has been achieved previously by incorporating the molecular spin singlet para-hydrogen into hydrogenation reaction products. We show here that a metal complex can facilitate the reversible interaction of para-hydrogen with a suitable organic substrate such that up to an 800-fold increase in proton, carbon, and nitrogen signal strengths are seen for the substrate without its hydrogenation. These polarized signals can be selectively detected when combined with methods that suppress background signals.

Electromagnetic dipole moments of charged baryons with bent crystals at the LHC

NASA Astrophysics Data System (ADS)

Bagli, E.; Bandiera, L.; Cavoto, G.; Guidi, V.; Henry, L.; Marangotto, D.; Martinez Vidal, F.; Mazzolari, A.; Merli, A.; Neri, N.; Ruiz Vidal, J.

2017-12-01

We propose a unique program of measurements of electric and magnetic dipole moments of charm, beauty and strange charged baryons at the LHC, based on the phenomenon of spin precession of channeled particles in bent crystals. Studies of crystal channeling and spin precession of positively- and negatively-charged particles are presented, along with feasibility studies and expected sensitivities for the proposed experiment using a layout based on the LHCb detector.

Strain-sensitive spin-state ordering in thin films of perovskite LaCoO3

NASA Astrophysics Data System (ADS)

Fujioka, J.; Yamasaki, Y.; Doi, A.; Nakao, H.; Kumai, R.; Murakami, Y.; Nakamura, M.; Kawasaki, M.; Arima, T.; Tokura, Y.

2015-11-01

We have investigated the lattice distortion coupled to the Co 3 d -spin-state ordering in thin films of perovskite LaCoO3 with various epitaxial strains by measurements of the magnetization, x-ray diffraction, and optical spectra. In the system with tensile strain about 0.5%, a lattice distortion characterized by the modulation vector q =(1 /6 ,1 /6 ,1 /6 ) emerges at 40 K, followed by a ferromagnetic ordering at 24 K. Alternatively, in systems with tensile strain exceeding 1%, the lattice distortion characterized by q =(1 /4 ,1 /4 ,1 /4 ) emerges at 120 K or higher, and subsequently the ferromagnetic or ferrimagnetic ordering occurs around 90 K. The evolution of infrared phonon spectra and resonant x-ray scattering at the Co K edge suggests that the population change in the Co 3 d spin state causes the strain-induced switching of spin-state ordering as well as of magnetic ordering in this canonical spin-state crossover system.

Van der Waals engineering of ferromagnetic semiconductor heterostructures for spin and valleytronics

DOE PAGES

Zhong, Ding; Seyler, Kyle L.; Linpeng, Xiayu; ...

2017-05-31

The integration of magnetic material with semiconductors has been fertile ground for fundamental science as well as of great practical interest toward the seamless integration of information processing and storage. We create van der Waals heterostructures formed by an ultrathin ferromagnetic semiconductor CrI 3 and a monolayer of WSe 2. We observe unprecedented control of the spin and valley pseudospin in WSe 2, where we detect a large magnetic exchange field of nearly 13 T and rapid switching of the WSe 2 valley splitting and polarization via flipping of the CrI 3 magnetization. The WSe2 photoluminescence intensity strongly depends onmore » the relative alignment between photoexcited spins in WSe 2 and the CrI 3 magnetization, because of ultrafast spin-dependent charge hopping across the heterostructure interface. The photoluminescence detection of valley pseudospin provides a simple and sensitive method to probe the intriguing domain dynamics in the ultrathin magnet, as well as the rich spin interactions within the heterostructure.« less

Characterization of atomic spin polarization lifetime of cesium vapor cells with neon buffer gas

NASA Astrophysics Data System (ADS)

Lou, Janet W.; Cranch, Geoffrey A.

2018-02-01

The dephasing time of spin-polarized atoms in an atomic vapor cell plays an important role in determining the stability of vapor-cell clocks as well as the sensitivity of optically-pumped magnetometers. The presence of a buffer gas can extend the lifetime of these atoms. Many vapor cell systems operate at a fixed (often elevated) temperature. For ambient temperature operation with no temperature control, it is necessary to characterize the temperature dependence as well. We present a spin-polarization lifetime study of Cesium vapor cells with different buffer gas pressures, and find good agreement with expectations based on the combined effects of wall collisions, spin exchange, and spin destruction. For our (7.5 mm diameter) vapor cells, the lifetime can be increased by two orders of magnitude by introducing Ne buffer gas up to 100 Torr. Additionally, the dependence of the lifetime on temperature is measured (25 - 47 oC) and simulated for the first time to our knowledge with reasonable agreement.

Spin-Selective Transmission and Devisable Chirality in Two-Layer Metasurfaces.

PubMed

Li, Zhancheng; Liu, Wenwei; Cheng, Hua; Chen, Shuqi; Tian, Jianguo

2017-08-15

Chirality is a nearly ubiquitous natural phenomenon. Its minute presence in most naturally occurring materials makes it incredibly difficult to detect. Recent advances in metasurfaces indicate that they exhibit devisable chirality in novel forms; this finding offers an effective opening for studying chirality and its features in such nanostructures. These metasurfaces display vast possibilities for highly sensitive chirality discrimination in biological and chemical systems. Here, we show that two-layer metasurfaces based on twisted nanorods can generate giant spin-selective transmission and support engineered chirality in the near-infrared region. Two designed metasurfaces with opposite spin-selective transmission are proposed for treatment as enantiomers and can be used widely for spin selection and enhanced chiral sensing. Specifically, we demonstrate that the chirality in these proposed metasurfaces can be adjusted effectively by simply changing the orientation angle between the twisted nanorods. Our results offer simple and straightforward rules for chirality engineering in metasurfaces and suggest intriguing possibilities for the applications of such metasurfaces in spin optics and chiral sensing.

Dark matter spin determination with directional direct detection experiments

NASA Astrophysics Data System (ADS)

Catena, Riccardo; Conrad, Jan; Döring, Christian; Ferella, Alfredo Davide; Krauss, Martin B.

2018-01-01

If dark matter has spin 0, only two WIMP-nucleon interaction operators can arise as leading operators from the nonrelativistic reduction of renormalizable single-mediator models for dark matter-quark interactions. Based on this crucial observation, we show that about 100 signal events at next generation directional detection experiments can be enough to enable a 2 σ rejection of the spin 0 dark matter hypothesis in favor of alternative hypotheses where the dark matter particle has spin 1 /2 or 1. In this context, directional sensitivity is crucial since anisotropy patterns in the sphere of nuclear recoil directions depend on the spin of the dark matter particle. For comparison, about 100 signal events are expected in a CF4 detector operating at a pressure of 30 torr with an exposure of approximately 26,000 cubic-meter-detector days for WIMPs of 100 GeV mass and a WIMP-fluorine scattering cross section of 0.25 pb. Comparable exposures require an array of cubic meter time projection chamber detectors.

Amplified Sensitivity of Nitrogen-Vacancy Spins in Nanodiamonds Using All-Optical Charge Readout.

PubMed

Hopper, David A; Grote, Richard R; Parks, Samuel M; Bassett, Lee C

2018-04-23

Nanodiamonds containing nitrogen-vacancy (NV) centers offer a versatile platform for sensing applications spanning from nanomagnetism to in vivo monitoring of cellular processes. In many cases, however, weak optical signals and poor contrast demand long acquisition times that prevent the measurement of environmental dynamics. Here, we demonstrate the ability to perform fast, high-contrast optical measurements of charge distributions in ensembles of NV centers in nanodiamonds and use the technique to improve the spin-readout signal-to-noise ratio through spin-to-charge conversion. A study of 38 nanodiamonds with sizes ranging between 20 and 70 nm, each hosting a small ensemble of NV centers, uncovers complex, multiple time scale dynamics due to radiative and nonradiative ionization and recombination processes. Nonetheless, the NV-containing nanodiamonds universally exhibit charge-dependent photoluminescence contrasts and the potential for enhanced spin readout using spin-to-charge conversion. We use the technique to speed up a T 1 relaxometry measurement by a factor of 5.

Separation and conversion dynamics of nuclear-spin isomers of gaseous methanol

PubMed Central

Sun, Zhen-Dong; Ge, Meihua; Zheng, Yujun

2015-01-01

All symmetrical molecules with non-zero nuclear spin exist in nature as nuclear-spin isomers (NSIs). However, owing to the lack of experimental information, knowledge is rare about interconversions of NSIs of gaseous molecules with torsional symmetry. Here we report our separation and conversion observations on NSI-torsion-specific transition systems of gaseous methanol from a light-induced drift experiment involving partially spatial separation of the ortho and para isomers. We find that vibrationally excited molecules of the methanol spin isomer have a smaller collision cross-section than their ground-state counterparts. Interconversion of the enriched ortho isomer with the para isomer, which is generally considered improbable, has been quantitatively studied by sensitive detections of the spectral intensities. Rather counterintuitively, this reveals that the interconversion is inhibited with increasing pressure. Our results suggest that the spin conversion mechanism in methanol is via a quantum relaxation process with the quantum Zeno effect induced by molecular collisions. PMID:25880882

Application of Double Spin-Echo Spiral Chemical Shift Imaging to Rapid Metabolic Mapping of Hyperpolarized [1-13C]-Pyruvate

PubMed Central

Josan, Sonal; Yen, Yi-Fen; Hurd, Ralph; Pfefferbaum, Adolf; Spielman, Daniel; Mayer, Dirk

2011-01-01

Undersampled spiral CSI (spCSI) using a free induction decay (FID) acquisition allows sub-second metabolic imaging of hyperpolarized 13C. Phase correction of the FID acquisition can be difficult, especially with contributions from aliased out-of-phase peaks. This work extends the spCSI sequence by incorporating double spin-echo radiofrequency (RF) pulses to eliminate the need for phase correction and obtain high quality spectra in magnitude mode. The sequence also provides an added benefit of attenuating signal from flowing spins, which can otherwise contaminate signal in the organ of interest. The refocusing pulses can potentially lead to a loss of hyperpolarized magnetization in dynamic imaging due to flow of spins through the fringe field of the RF coil, where the refocusing pulses fail to provide complete refocusing. Care must be taken for dynamic imaging to ensure that the spins remain within the B1-homogeneous sensitive volume of the RF coil. PMID:21316280

Remote microwave monitoring of magnetization switching in CoFeB/Ta/CoFeB spin logic device

NASA Astrophysics Data System (ADS)

Morgunov, R.; L'vova, G.; Talantsev, A.; Koplak, O.; Petit-Watelot, S.; Devaux, X.; Migot, S.; Lu, Y.; Mangin, S.

2017-05-01

Stable magnetic states of the MgO/CoFeB/Ta/CoFeB/MgO/Ta spin valve as well as transitions between the states were detected by microwave magnetoresistance (MMR) measured in the cavity of an electron spin resonance spectrometer. Advantages of this experimental technique are the possibility to study the orientation dependence of the MMR, the absence of the additional contact/sample interfaces, the wireless control of the spin valves, and the compatibility of the MMR measurements with ferromagnetic resonance experiments. The magnetic field dependence of the first derivation of the microwave absorption allows one to judge about the negative magnetoresistance of the layers and positive interlayer giant magnetoresistance. The obtained experimental results could be used for engineering of the microwave high sensitive sensors available for remote identification of the stable magnetic and logic states of the spin valves needful in medical spintronics to detect biological objects labeled with nanoparticles.

Van der Waals engineering of ferromagnetic semiconductor heterostructures for spin and valleytronics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhong, Ding; Seyler, Kyle L.; Linpeng, Xiayu

The integration of magnetic material with semiconductors has been fertile ground for fundamental science as well as of great practical interest toward the seamless integration of information processing and storage. We create van der Waals heterostructures formed by an ultrathin ferromagnetic semiconductor CrI 3 and a monolayer of WSe 2. We observe unprecedented control of the spin and valley pseudospin in WSe 2, where we detect a large magnetic exchange field of nearly 13 T and rapid switching of the WSe 2 valley splitting and polarization via flipping of the CrI 3 magnetization. The WSe2 photoluminescence intensity strongly depends onmore » the relative alignment between photoexcited spins in WSe 2 and the CrI 3 magnetization, because of ultrafast spin-dependent charge hopping across the heterostructure interface. The photoluminescence detection of valley pseudospin provides a simple and sensitive method to probe the intriguing domain dynamics in the ultrathin magnet, as well as the rich spin interactions within the heterostructure.« less

Solid-state dynamic nuclear polarization at 263 GHz: spectrometer design and experimental results†

PubMed Central

Rosay, Melanie; Tometich, Leo; Pawsey, Shane; Bader, Reto; Schauwecker, Robert; Blank, Monica; Borchard, Philipp M.; Cauffman, Stephen R.; Felch, Kevin L.; Weber, Ralph T.; Temkin, Richard J.; Griffin, Robert G.; Maas, Werner E.

2015-01-01

Dynamic Nuclear Polarization (DNP) experiments transfer polarization from electron spins to nuclear spins with microwave irradiation of the electron spins for enhanced sensitivity in nuclear magnetic resonance (NMR) spectroscopy. Design and testing of a spectrometer for magic angle spinning (MAS) DNP experiments at 263 GHz microwave frequency, 400 MHz 1H frequency is described. Microwaves are generated by a novel continuous-wave gyrotron, transmitted to the NMR probe via a transmission line, and irradiated on a 3.2 mm rotor for MAS DNP experiments. DNP signal enhancements of up to 80 have been measured at 95 K on urea and proline in water–glycerol with the biradical polarizing agent TOTAPOL. We characterize the experimental parameters affecting the DNP efficiency: the magnetic field dependence, temperature dependence and polarization build-up times, microwave power dependence, sample heating effects, and spinning frequency dependence of the DNP signal enhancement. Stable system operation, including DNP performance, is also demonstrated over a 36 h period. PMID:20449524

Spectrum of the Nuclear Environment for GaAs Spin Qubits.

PubMed

Malinowski, Filip K; Martins, Frederico; Cywiński, Łukasz; Rudner, Mark S; Nissen, Peter D; Fallahi, Saeed; Gardner, Geoffrey C; Manfra, Michael J; Marcus, Charles M; Kuemmeth, Ferdinand

2017-04-28

Using a singlet-triplet spin qubit as a sensitive spectrometer of the GaAs nuclear spin bath, we demonstrate that the spectrum of Overhauser noise agrees with a classical spin diffusion model over 6 orders of magnitude in frequency, from 1 mHz to 1 kHz, is flat below 10 mHz, and falls as 1/f^{2} for frequency f≳1  Hz. Increasing the applied magnetic field from 0.1 to 0.75 T suppresses electron-mediated spin diffusion, which decreases the spectral content in the 1/f^{2} region and lowers the saturation frequency, each by an order of magnitude, consistent with a numerical model. Spectral content at megahertz frequencies is accessed using dynamical decoupling, which shows a crossover from the few-pulse regime (≲16π pulses), where transverse Overhauser fluctuations dominate dephasing, to the many-pulse regime (≳32 π pulses), where longitudinal Overhauser fluctuations with a 1/f spectrum dominate.

Biocompatible click chemistry enabled compartment-specific pH measurement inside E. coli.

PubMed

Yang, Maiyun; Jalloh, Abubakar S; Wei, Wei; Zhao, Jing; Wu, Peng; Chen, Peng R

2014-09-19

Bioorthogonal reactions, especially the Cu(I)-catalysed azide-alkyne cycloaddition, have revolutionized our ability to label and manipulate biomolecules under living conditions. The cytotoxicity of Cu(I) ions, however, has hindered the application of this reaction in the internal space of living cells. By systematically surveying a panel of Cu(I)-stabilizing ligands in promoting protein labelling within the cytoplasm of Escherichia coli, we identify a highly efficient and biocompatible catalyst for intracellular modification of proteins by azide-alkyne cycloaddition. This reaction permits us to conjugate an environment-sensitive fluorophore site specifically onto HdeA, an acid-stress chaperone that adopts pH-dependent conformational changes, in both the periplasm and cytoplasm of E. coli. The resulting protein-fluorophore hybrid pH indicators enable compartment-specific pH measurement to determine the pH gradient across the E. coli cytoplasmic membrane. This construct also allows the measurement of E. coli transmembrane potential, and the determination of the proton motive force across its inner membrane under normal and acid-stress conditions.

Synthesis of biocompatible and highly photoluminescent nitrogen doped carbon dots from lime: analytical applications and optimization using response surface methodology.

PubMed

Barati, Ali; Shamsipur, Mojtaba; Arkan, Elham; Hosseinzadeh, Leila; Abdollahi, Hamid

2015-02-01

Herein, a facile hydrothermal treatment of lime juice to prepare biocompatible nitrogen-doped carbon quantum dots (N-CQDs) in the presence of ammonium bicarbonate as a nitrogen source has been presented. The resulting N-CQDs exhibited excitation and pH independent emission behavior; with the quantum yield (QY) up to 40%, which was several times greater than the corresponding value for CQDs with no added nitrogen source. The N-CQDs were applied as a fluorescent probe for the sensitive and selective detection of Hg(2+) ions with a detection limit of 14 nM. Moreover, the cellular uptake and cytotoxicity of N-CQDs at different concentration ranges from 0.0 to 0.8 mg/ml were investigated by using PC12 cells as a model system. Response surface methodology was used for optimization and systematic investigation of the main variables that influence the QY, including reaction time, reaction temperature, and ammonium bicarbonate weight. Copyright © 2014. Published by Elsevier B.V.

Spin-dependent limits from the DRIFT-IId directional dark matter detector

NASA Astrophysics Data System (ADS)

Daw, E.; Fox, J. R.; Gauvreau, J.-L.; Ghag, C.; Harmon, L. J.; Gold, M.; Lee, E. R.; Loomba, D.; Miller, E. H.; Murphy, A. Stj.; Paling, S. M.; Landers, J. M.; Pipe, M.; Pushkin, K.; Robinson, M.; Snowden-Ifft, D. P.; Spooner, N. J. C.; Walker, D.

2012-02-01

Data are presented from the DRIFT-IId detector operated in the Boulby Underground Science Facility in England. A 0.8 m3 fiducial volume, containing partial pressures of 30 Torr CS2 and 10 Torr CF4, was exposed for a duration of 47.4 live-time days with sufficient passive shielding to provide a neutron free environment within the detector. The nuclear recoil events seen are consistent with a remaining low-level background from the decay of radon daughters attached to the central cathode of the detector. However, charge from such events must drift across the entire width of the detector, and thus display large diffusion upon reaching the readout planes of the device. Exploiting this feature, it is shown to be possible to reject energy depositions from these Radon Progeny Recoil events while still retaining sensitivity to fiducial-volume nuclear recoil events. The response of the detector is then interpreted, using the F nuclei content of the gas, in terms of sensitivity to proton spin-dependent WIMP-nucleon interactions, displaying a minimum in sensitivity cross section at 1.8 pb for a WIMP mass of 100 GeV/c2. This sensitivity was achieved without compromising the direction sensitivity of DRIFT.

Temperature Dependence of the Spin-Hall Conductivity of a Two-Dimensional Impure Rashba Electron Gas in the Presence of Electron-Phonon and Electron-Electron Interactions

NASA Astrophysics Data System (ADS)

Yavari, H.; Mokhtari, M.; Bayervand, A.

2015-03-01

Based on Kubo's linear response formalism, temperature dependence of the spin-Hall conductivity of a two-dimensional impure (magnetic and nonmagnetic impurities) Rashba electron gas in the presence of electron-electron and electron-phonon interactions is analyzed theoretically. We will show that the temperature dependence of the spin-Hall conductivity is determined by the relaxation rates due to these interactions. At low temperature, the elastic lifetimes ( and are determined by magnetic and nonmagnetic impurity concentrations which are independent of the temperature, while the inelastic lifetimes ( and related to the electron-electron and electron-phonon interactions, decrease when the temperature increases. We will also show that since the spin-Hall conductivity is sensitive to temperature, we can distinguish the intrinsic and extrinsic contributions.

Origin of the spin Seebeck effect in compensated ferrimagnets

PubMed Central

Geprägs, Stephan; Kehlberger, Andreas; Coletta, Francesco Della; Qiu, Zhiyong; Guo, Er-Jia; Schulz, Tomek; Mix, Christian; Meyer, Sibylle; Kamra, Akashdeep; Althammer, Matthias; Huebl, Hans; Jakob, Gerhard; Ohnuma, Yuichi; Adachi, Hiroto; Barker, Joseph; Maekawa, Sadamichi; Bauer, Gerrit E. W.; Saitoh, Eiji; Gross, Rudolf; Goennenwein, Sebastian T. B.; Kläui, Mathias

2016-01-01

Magnons are the elementary excitations of a magnetically ordered system. In ferromagnets, only a single band of low-energy magnons needs to be considered, but in ferrimagnets the situation is more complex owing to different magnetic sublattices involved. In this case, low lying optical modes exist that can affect the dynamical response. Here we show that the spin Seebeck effect (SSE) is sensitive to the complexities of the magnon spectrum. The SSE is caused by thermally excited spin dynamics that are converted to a voltage by the inverse spin Hall effect at the interface to a heavy metal contact. By investigating the temperature dependence of the SSE in the ferrimagnet gadolinium iron garnet, with a magnetic compensation point near room temperature, we demonstrate that higher-energy exchange magnons play a key role in the SSE. PMID:26842873

Gate-Controlled Spin-Valley Locking of Resident Carriers in WSe2 Monolayers

NASA Astrophysics Data System (ADS)

Dey, P.; Yang, Luyi; Robert, C.; Wang, G.; Urbaszek, B.; Marie, X.; Crooker, S. A.

2017-09-01

Using time-resolved Kerr rotation, we measure the spin-valley dynamics of resident electrons and holes in single charge-tunable monolayers of the archetypal transition-metal dichalcogenide (TMD) semiconductor WSe2 . In the n -type regime, we observe long (˜130 ns ) polarization relaxation of electrons that is sensitive to in-plane magnetic fields By, indicating spin relaxation. In marked contrast, extraordinarily long (˜2 μ s ) polarization relaxation of holes is revealed in the p -type regime, which is unaffected by By, directly confirming long-standing expectations of strong spin-valley locking of holes in the valence band of monolayer TMDs. Supported by continuous-wave Kerr spectroscopy and Hanle measurements, these studies provide a unified picture of carrier polarization dynamics in monolayer TMDs, which can guide design principles for future valleytronic devices.

Antiparallel pinned NiO spin valve sensor for GMR head application (invited)

NASA Astrophysics Data System (ADS)

Pinarbasi, M.; Metin, S.; Gill, H.; Parker, M.; Gurney, B.; Carey, M.; Tsang, C.

2000-05-01

NiO antiferromagnetic material possesses certain advantages for spin valve applications and has attracted considerable attention. Some of the key advantages are its insulating properties, very high corrosion resistance, less sensitivity to composition, and its low reset temperature. This material, however, has a low blocking temperature which prevents its application to simple spin valve designs. The use of this material in spin valve structures required significant improvements in thermal stability, blocking temperature, and the spin valve design. In the present study, the blocking temperature and the blocking temperature distribution of the NiO films have been improved by depositing the films reactively using ion beam sputtering. A number of improvements in the processing method and deposition system had to be made to allow full NiO spin valve deposition for mass production. Another critical part was the use of antiparallel pinned design in place of the simple design to improve the thermal stability of the NiO spin valves as read elements at disk drive temperatures. The selection of the ferromagnetic pinned layers and the Ru spacer thickness in AP-pinned spin valves has significant impact on the behavior of the devices. These spin valves are all bottom type, NiO/PL1/Ru/PL2/Cu/Co/NiFe/Ta, where the metallic portion of the spin valve is deposited on top of the NiO AF layer. The PL1 and PL2 are ferromagnetic layers comprising NiFe and Co layers. Read elements have been made using these spin valves that delivered areal densities of 12 Gbit/in. These topics and other improvements which resulted in successful use of NiO spin valves as GMR heads in hard disk drives will be discussed.

Resonance and Variable Temperature Raman Studies of Chloroperoxidase and Methemoglobin.

NASA Astrophysics Data System (ADS)

Remba, Ronald David

1980-12-01

Raman spectra of the heme proteins chloroperoxidase and methemoglobin, chemically and temperature modified, are obtained for laser excitation near the Soret absorption band. Numerous biochemical and physical results are obtained. The following observations for chloroperoxidase have been made. The scattered intensity for resonance (406.7 nm) excitation is at least twenty times that for near resonance (457.9 nm) excitation. In resonance only totally symmetric modes are enhanced. The positions of marker band I ((TURN) 1370 cm(' -1)) for both the native and reduced enzymes are lower than expected for high-spin heme proteins indicating a strongly electron donating axial ligand. From shifts in spin-sensitive Raman peaks as the temperature is lowered, a high-spin to low-spin transition of the heme iron is inferred. Raman spectra of chloroperoxidase liganded with small ions indicate that there is a second anion binding site near the heme. Photo-dissociation of CO from reduced chloroperoxidase is observed. The position of marker band I in the CO complex indicates that electron density is transferred from the heme onto the CO. The resonance Raman spectra of chloroperoxidase and cytochrome P-450 are nearly identical and are very different from those of horseradish peroxidase and cytochrome c. These results, particularly for the reduced enzymes, indicate that the heme sites in chloroperoxidase and P -450 are essentially the same. Raman spectra of a number of methemoglobins complexed with various small ions are obtained as a function of temperature in the region of spin-sensitive marker band (II) ((TURN) 1500 cm('-1)) for laser excitation near the Soret absorption band. For certain ligands, H(,2)O, N(,3)('-), OCN('-), OH('-) and SCN('-), the iron spin state changes from high spin to low spin with decreasing temperature. The relative spin concentrations are monitored by measuring the Raman intensity ratio, I(,h)/I(,1), of the high-spin and low -spin versions of marker band (II) as a function of temperature. This is the first study where the marker band technique is used to measure quantitatively spin transitions. For hydroxide and cyanate methemoglobin, log(I(,h)/I(,1)) varies linearly with 1/T, indicating a high-spin/low-spin thermal equilibrium. The data are analyzed to extract enthalpic and entropic changes. (DELTA)H values from Raman and static magnetic susceptibility techniques show good agreement. (DELTA)S values for horse hydroxide methemoglobin also agree. However, for cyanate methemoglobin, Raman and susceptibility (DELTA)S values differ substantially. Other evidence (ESR, optical, etc.) supports the Raman result. The discrepancy is probably due to the effects of freezing on the protein solution. Other methemoglobins show a discontinuity in the Raman intensity ratio at the freezing transition indicating a non-equilibrium situation where the freezing process drives the spin transition. Effects of freezing the protein solution on the spin transition are discussed. Both the high-spin and low-spin Raman frequencies are observed to remain constant (within (+OR-) 2 cm('-1)) when the temperature is varied. This is discussed in terms of core expansion and heme deformation. Experimental (DELTA)S values are much larger than the spin-only value. This is discussed in terms of a linear temperature dependence on the energy gap between the ('2)T(,2) ground state and the ('6)A(,1) first excited state. Variable temperature Raman data for carp azide methemoglobin with and without IHP indicate that the free energy for the spin transition decreases by 0.6 (+OR-) 0.3 kcal/mole when hemoglobin quaternary structure changes from R to T. Lack of any frequency shift in either the high-spin or low-spin Raman band upon addition of IHP is consistent with other evidence indicating no iron movement upon conversion of R to T quaternary forms.

Whole organic electronic synapses for dopamine detection

NASA Astrophysics Data System (ADS)

Giordani, Martina; Di Lauro, Michele; Berto, Marcello; Bortolotti, Carlo A.; Vuillaume, Dominique; Gomes, Henrique L.; Zoli, Michele; Biscarini, Fabio

2016-09-01

A whole organic artificial synapse has been fabricated by patterning PEDOT:PSS electrodes on PDMS that are biased in frequency to yield a STP response. The timescale of the STP response is shown to be sensitive to the concentration of dopamine, DA, a neurotransmitter relevant for monitoring the development of Parkinson's disease and potential locoregional therapies. The sensitivity of the sensor towards DA has been validated comparing signal variation in the presence of DA and its principal interfering agent, ascorbic acid, AA. The whole organic synapse is biocompatible, soft and flexible, and is attractive for implantable devices aimed to real-time monitoring of DA concentration in bodily fluids. This may open applications in chronic neurodegenerative diseases such as Parkinson's disease.

MnNi-based spin valve sensors combining high thermal stability, small footprint and pTesla detectivities

NASA Astrophysics Data System (ADS)

Silva, Marília; Leitao, Diana C.; Cardoso, Susana; Freitas, Paulo

2018-05-01

Magnetoresistive sensors with high thermal robustness, low noise and high spatial resolution are the answer to a number of challenging applications. Spin valve sensors including MnNi as antiferromagnet layer provide higher exchange bias field and improved thermal stability. In this work, the influence of the buffer layer type (Ta, NiFeCr) and thickness on key sensor parameters (e.g. offset field, Hf) is investigated. A Ta buffer layer promotes a strong (111) texture which leads to a higher value of MR. In contrast, Hf is lower for NiFeCr buffer. Micrometric sensors display thermal noise levels of 1 nT/Hz1/2 and 571 pT/Hz1/2 for a sensor height (h) of 2 and 4 μm, respectively. The temperature dependence of MR and sensitivity is also addressed and compared with MnIr based spin valves. In this case, MR abruptly decreases after heating at 160°C (without magnetic field), contrary to MnNi-based spin valves, where only a 10% MR decrease (relative to the initial value) is seen at 275°C. Finally, to further decrease the noise levels and improve detectivity, MnNi spin-valves are deposited vertically, and connected in parallel and series (in-plane) to create a device with low resistance and high sensitivity. A field detection at thermal level of 346 pT/Hz1/2 is achieved for a device with a total of 300 SVs (4 vertical, 15 in series, 5 in parallel).

Sensitive imaging of magnetization structure and dynamics using picosecond laser heating

NASA Astrophysics Data System (ADS)

Bartell, Jason; Jermain, Colin; Aradhya, Sriharsha; Brangham, Jack; Yang, Fengyuan; Ralph, Daniel; Fuchs, Gregory

We demonstrate the time-resolved longitudinal spin Seebeck effect (TRLSSE) as the basis for an ultrafast, high-resolution, and sensitive microscope for imaging ferromagnetic insulator/normal metal spintronic devices. By focusing a picosecond laser to 0.7 μm, we generate a sub-100 ps electrical signal from the combination of the TRLSSE and the inverse spin Hall effect in yittrium iron garnet (YIG)/platinum (Pt) bilayers. This signal is a spatiotemporal measurement of the local, in-plane magnetic orientation of YIG with outstanding sensitivity better than 0.3° /√{ Hz } in samples with 20 nm of YIG. Static imaging of YIG/Pt devices reveals variations in the local magnetic anisotropy on a few micron scale. Phase-sensitive ferromagnetic resonance imaging reveals corresponding variations in the resonance field, amplitude, phase, and linewidth. These results show the TRLSSE is a powerful tool for static and dynamic studies of spintronic devices made with ferromagnetic insulators. This research was supported by the AFOSR (FA9550-14-1-0243) and by NSF (DMR-1406333, DMR-1507274, and DMR-1120296).

Microenvironment-Sensitive Multimodal Contrast Agent for Prostate Cancer Diagnosis

DTIC Science & Technology

2015-10-01

with a biopolymer (i.e. starch ) to improve biocompatibility, and tagged with prostate cancer-targeting ligands. A significant challenge to translation... starch coating of 50 nm and 100 nm SPIONs was crosslinked and coated with amine groups, and then functionalized with NHS-polyethylene glycol (PEG) of...varying molecular weight (i.e., 2k, 5k or 20k Da) as shown in Scheme 1. Scheme 1. Surface modification of starch -coated SPIONs into aminated and

Microenvironment Sensitive Multimodal Contrast Agent for Prostate Cancer Diagnosis

DTIC Science & Technology

2016-10-01

coated with a biopolymer (i.e. starch ) to improve biocompatibility, and tagged with prostate cancer-targeting ligands. A significant challenge to...The starch coating of 50 nm and 100 nm SPIONs was crosslinked and coated with amine groups, and then functionalized with NHS-polyethylene glycol (PEG...of varying molecular weight (i.e., 2k, 5k or 20k Da) as shown in Scheme 1. Scheme 1. Surface modification of starch -coated SPIONs into aminated

Micropatterning of poly(dimethylsiloxane) using a photoresist lift-off technique for selective electrical insulation of microelectrode arrays

PubMed Central

Park, Jaewon; Kim, Hyun Soo; Han, Arum

2009-01-01

A poly(dimethylsiloxane) (PDMS) patterning method based on a photoresist lift-off technique to make an electrical insulation layer with selective openings is presented. The method enables creating PDMS patterns with small features and various thicknesses without any limitation in the designs and without the need for complicated processes or expensive equipments. Patterned PDMS layers were created by spin-coating liquid phase PDMS on top of a substrate having sacrificial photoresist patterns, followed by a photoresist lift-off process. The thickness of the patterned PDMS layers could be accurately controlled (6.5–24 µm) by adjusting processing parameters such as PDMS spin-coating speeds, PDMS dilution ratios, and sacrificial photoresist thicknesses. PDMS features as small as 15 µm were successfully patterned and the effects of each processing parameter on the final patterns were investigated. Electrical resistance tests between adjacent electrodes with and without the insulation layer showed that the patterned PDMS layer functions properly as an electrical insulation layer. Biocompatibility of the patterned PDMS layer was confirmed by culturing primary neuron cells on top of the layer for up to two weeks. An extensive neuronal network was successfully formed, showing that this PDMS patterning method can be applied to various biosensing microdevices. The utility of this fabrication method was further demonstrated by successfully creating a patterned electrical insulation layer on flexible substrates containing multi-electrode arrays. PMID:19946385

ZnO based potentiometric and amperometric nanosensors.

PubMed

Willander, Magnus; Khun, Kimleang; Ibupoto, Zafar Hussain

2014-09-01

The existence of nanomaterials provides the solid platform for sensing applications due to owing of high sensitivity and a low concentration limit of detection. More likely used nanomaterials for sensing applications includes gold nanoparticles, carbon nanotubes, magnetic nanoparticles such as Fe3O4, quantum dots and metal oxides etc. Recently nanomaterial and biological detection becomes an interdisciplinary field and is very much focussed by the researchers. Among metal oxides ZnO is largely considered due to its less toxic nature, biocompatible, cheap and easy to synthesis. ZnO nanomaterial is highly used for the chemical sensing, especially electrochemical sensing due to its fascinating properties such as high surface to volume ratio, atoxic, biosafe and biocompatible. Moreover, ZnO nanostructures exhibit unique features which could expose a suitable nanoenviroment for the immobilization of proteineous material such as enzymes, DNA, antibodies, etc. and in doing so it retains the biological efficiency of the immobilized bio sensitive material. The following review describes the two different coatings (i.e., ionophore and enzyme) on the surface of ZnO nanorods for the chemical sensing of zinc ion detection, thallium (I) ion detection, and L-lactic acid and the measurement of galactose molecules. ZnO nanorods provide the excellent transducing properties in the generation of strong electrical signals. Moreover, this review is very much focused on the applications of ZnO nanostructures in the sensing field.

Antimicrobial Effect of Biocompatible Silicon Nanoparticles Activated Using Therapeutic Ultrasound.

PubMed

Shevchenko, Svetlana N; Burkhardt, Markus; Sheval, Eugene V; Natashina, Ulyana A; Grosse, Christina; Nikolaev, Alexander L; Gopin, Alexander V; Neugebauer, Ute; Kudryavtsev, Andrew A; Sivakov, Vladimir; Osminkina, Liubov A

2017-03-14

In this study, we report a method for the suppression of Escherichia coli (E. coli) vitality by means of therapeutic ultrasound irradiation (USI) using biocompatible silicon nanoparticles as cavitation sensitizers. Silicon nanoparticles without (SiNPs) and with polysaccharide (dextran) coating (DSiNPs) were used. Both types of nanoparticles were nontoxic to Hep 2 cells up to a concentration of 2 mg/mL. The treatment of bacteria with nanoparticles and application of 1 W/cm 2 USI resulted in the reduction of their viabilities up to 35 and 72% for SiNPs and DSiNPs, respectively. The higher bacterial viability reduction for DSiNPs as compared with SiNPs can be explained by the fact that the biopolymer shell of the polysaccharide provides a stronger adhesion of nanoparticles to the bacterial surface. Transmission electron microscopy (TEM) studies showed that the bacterial lipid shell was partially perforated after the combined treatment of DSiNPs and USI, which can be explained by the lysis of bacterial membrane due to the cavitation sensitized by the SiNPs. Furthermore, we have shown that 100% inhibition of E. coli bacterial colony growth is possible by coupling the treatments of DSiNPs and USI with an increased intensity of up to 3 W/cm 2 . The observed results reveal the application of SiNPs as promising antimicrobial agents.

Advances in Targeted Pesticides with Environmentally Responsive Controlled Release by Nanotechnology

PubMed Central

Huang, Bingna; Chen, Feifei; Shen, Yue; Wang, Yan; Sun, Changjiao; Zhao, Xiang; Cui, Bo; Gao, Fei; Zeng, Zhanghua; Cui, Haixin

2018-01-01

Pesticides are the basis for defending against major biological disasters and important for ensuring national food security. Biocompatible, biodegradable, intelligent, and responsive materials are currently an emerging area of interest in the field of efficient, safe, and green pesticide formulation. Using nanotechnology to design and prepare targeted pesticides with environmentally responsive controlled release via compound and chemical modifications has also shown great potential in creating novel formulations. In this review, special attention has been paid to intelligent pesticides with precise controlled release modes that can respond to micro-ecological environment changes such as light-sensitivity, thermo-sensitivity, humidity sensitivity, soil pH, and enzyme activity. Moreover, establishing intelligent and controlled pesticide release technologies using nanomaterials are reported. These technologies could increase pesticide-loading, improve the dispersibility and stability of active ingredients, and promote target ability. PMID:29439498

Biocompatibility of 4-META/MMA-TBB resin used as a dental luting agent.

PubMed

Nakagawa, Kaori; Saita, Makiko; Ikeda, Takayuki; Hirota, Makoto; Park, Wonhee; Lee, Masaichi Chang-Il; Ogawa, Takahiro

2015-07-01

The bonding and biological properties of currently used luting/cementing materials need to be improved. 4-Acryloyloxyethyl trimellitate anhydride/methyl methacrylate-tri-n-butylborane (4-META/MMA-TBB) resin is primarily used for splinting mobile teeth or treating fractured teeth. It undergoes moisture-resistant polymerization and bonds strongly to dentin and metals. The purpose of this in vitro study was to compare the biological and biochemical properties META/MMA-TBB resin with those of conventional polymethyl methacrylate (PMMA)-MMA resin and other currently used luting materials in order to determine whether it may be a viable dental luting agent. The degree of polymerization of 4-META/MMA-TBB resin, PMMA-MMA autopolymerizing resin, 10-methacryloyloxydecyl dihydrogen phosphate-dimethacrylate (MDP-DMA) adhesive resin, and a glass ionomer cement was measured by Fourier-transformed infrared spectroscopy. Free radical production during setting was evaluated by electron spin resonance (ESR) spectroscopy. Rat dental pulp cells cultured on these materials were examined for cell viability, attachment, proliferation, and functional phenotype. The degree of polymerization of 4-META/MMA-TBB resin was 82% thirty minutes after preparation, compared to 66% for PMMA-MMA autopolymerizing resin. ESR spectroscopy revealed free radical production from 4-META/MMA-TBB resin and glass ionomer cement was equivalent 24 hours after preparation, with no spike in radical generation observed. In contrast, free radical production from PMMA-MMA and MDP-DMA adhesive resins was rapid and sustained and 10 to 20 times greater than that from 4-META/MMA-TBB. The percentage of viable dental pulp cells 24 hours after seeding was considerably higher on MDP-DMA and 4-META/MMA-TBB resin than on glass ionomer cement. Cell number, proliferation, and alkaline phosphatase activity were highest on 4-META/MMA-TBB resin and lowest on the glass ionomer cement. 4-META/MMA-TBB resin is at least as biocompatible, and perhaps even more biocompatible, than other current luting materials, with fast, favorable, and nontoxic polymerization properties. Further in vivo and human studies of 4-META/MMA-TBB resin as a dental luting agent are warranted. Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Sensitivity quantification of remote detection NMR and MRI

NASA Astrophysics Data System (ADS)

Granwehr, J.; Seeley, J. A.

2006-04-01

A sensitivity analysis is presented of the remote detection NMR technique, which facilitates the spatial separation of encoding and detection of spin magnetization. Three different cases are considered: remote detection of a transient signal that must be encoded point-by-point like a free induction decay, remote detection of an experiment where the transient dimension is reduced to one data point like phase encoding in an imaging experiment, and time-of-flight (TOF) flow visualization. For all cases, the sensitivity enhancement is proportional to the relative sensitivity between the remote detector and the circuit that is used for encoding. It is shown for the case of an encoded transient signal that the sensitivity does not scale unfavorably with the number of encoded points compared to direct detection. Remote enhancement scales as the square root of the ratio of corresponding relaxation times in the two detection environments. Thus, remote detection especially increases the sensitivity of imaging experiments of porous materials with large susceptibility gradients, which cause a rapid dephasing of transverse spin magnetization. Finally, TOF remote detection, in which the detection volume is smaller than the encoded fluid volume, allows partial images corresponding to different time intervals between encoding and detection to be recorded. These partial images, which contain information about the fluid displacement, can be recorded, in an ideal case, with the same sensitivity as the full image detected in a single step with a larger coil.

Spin-locking of half-integer quadrupolar nuclei in nuclear magnetic resonance of solids: second-order quadrupolar and resonance offset effects.

PubMed

Ashbrook, Sharon E; Wimperis, Stephen

2009-11-21

Spin-locking of spin I=3/2 and I=5/2 nuclei in the presence of small resonance offset and second-order quadrupolar interactions has been investigated using both exact and approximate theoretical and experimental nuclear magnetic resonance (NMR) approaches. In the presence of second-order quadrupolar interactions, we show that the initial rapid dephasing that arises from the noncommutation of the state prepared by the first pulse and the spin-locking Hamiltonian gives rise to tensor components of the spin density matrix that are antisymmetric with respect to inversion, in addition to those symmetric with respect to inversion that are found when only a first-order quadrupolar interaction is considered. We also find that spin-locking of multiple-quantum coherence in a static solid is much more sensitive to resonance offset than that of single-quantum coherence and show that good spin-locking of multiple-quantum coherence can still be achieved if the resonance offset matches the second-order shift of the multiple-quantum coherence in the appropriate reference frame. Under magic angle spinning (MAS) conditions, and in the "adiabatic" limit, we demonstrate that rotor-driven interconversion of central-transition single- and three-quantum coherences for a spin I=3/2 nucleus can be best achieved by performing the spin-locking on resonance with the three-quantum coherence in the three-quantum frame. Finally, in the "sudden" MAS limit, we show that spin I=3/2 spin-locking behavior is generally similar to that found in static solids, except when the central-transition nutation rate matches a multiple of the MAS rate and a variety of rotary resonance phenomena are observed depending on the internal spin interactions present. This investigation should aid in the application of spin-locking techniques to multiple-quantum NMR of quadrupolar nuclei and of cross-polarization and homonuclear dipolar recoupling experiments to quadrupolar nuclei such as (7)Li, (11)B, (17)O, (23)Na, and (27)Al.

Magnetic defects in chemically converted graphene nanoribbons: electron spin resonance investigation

NASA Astrophysics Data System (ADS)

Singamaneni, Srinivasa Rao; Stesmans, Andre; van Tol, Johan; Kosynkin, D. V.; Tour, James M.

2014-04-01

Electronic spin transport properties of graphene nanoribbons (GNRs) are influenced by the presence of adatoms, adsorbates and edge functionalization. To improve the understanding of the factors that influence the spin properties of GNRs, local (element) spin-sensitive techniques such as electron spin resonance (ESR) spectroscopy are important for spintronics applications. Here, we present results of multi-frequency continuous wave (CW), pulse and hyperfine sublevel correlation (HYSCORE) ESR spectroscopy measurements performed on oxidatively unzipped graphene nanoribbons (GNRs), which were subsequently chemically converted (CCGNRs) with hydrazine. ESR spectra at 336 GHz reveal an isotropic ESR signal from the CCGNRs, of which the temperature dependence of its line width indicates the presence of localized unpaired electronic states. Upon functionalization of CCGNRs with 4-nitrobenzene diazonium tetrafluoroborate, the ESR signal is found to be 2 times narrower than that of pristine ribbons. NH3 adsorption/desorption on CCGNRs is shown to narrow the signal, while retaining the signal intensity and g value. The electron spin-spin relaxation process at 10 K is found to be characterized by slow (163 ns) and fast (39 ns) components. HYSCORE ESR data demonstrate the explicit presence of protons and 13C atoms. With the provided identification of intrinsic point magnetic defects such as proton and 13C has been reported, which are roadblocks to spin travel in graphene-based materials, this work could help in advancing the present fundamental understanding on the edge-spin (or magnetic)-based transport properties of CCGNRs.

Hunting the Gluon Orbital Angular Momentum at the Electron-Ion Collider.

PubMed

Ji, Xiangdong; Yuan, Feng; Zhao, Yong

2017-05-12

Applying the connection between the parton Wigner distribution and orbital angular momentum (OAM), we investigate the probe of the gluon OAM in hard scattering processes at the planned electron-ion collider. We show that the single longitudinal target-spin asymmetry in the hard diffractive dijet production is very sensitive to the gluon OAM distribution. The associated spin asymmetry leads to a characteristic azimuthal angular correlation of sin(ϕ_{q}-ϕ_{Δ}), where ϕ_{Δ} and ϕ_{q} are the azimuthal angles of the proton momentum transfer and the relative transverse momentum between the quark-antiquark pair. This study may motivate a first measurement of the gluon OAM in the proton spin sum rule.

Enhancing NMR of insensitive nuclei by transfer of SABRE spin hyperpolarization

NASA Astrophysics Data System (ADS)

Pravdivtsev, Andrey N.; Yurkovskaya, Alexandra V.; Zimmermann, Herbert; Vieth, Hans-Martin; Ivanov, Konstantin L.

2016-09-01

We describe the performance of methods for enhancing NMR (Nuclear Magnetic Resonance) signals of "insensitive", but important NMR nuclei, which are based on the SABRE (Signal Amplification By Reversible Exchange) technique, i.e., on spin order transfer from parahydrogen (H2 molecule in its nuclear singlet spin state) to a substrate in a transient organometallic complex. Here such transfer is performed at high magnetic fields by INEPT-type NMR pulse sequences, modified for SABRE. Signal enhancements up to three orders of magnitude are obtained for 15N nuclei; the possibility of sensitive detection of 2D-NMR 1H-15N spectra of SABRE complexes and substrates is demonstrated.

A proposed measurement of optical orbital and spin angular momentum and its implications for photon angular momentum

NASA Astrophysics Data System (ADS)

Leader, Elliot

2018-04-01

The expression for the total angular momentum carried by a laser optical vortex beam, splits, in the paraxial approximation, into two terms which seem to represent orbital and spin angular momentum respectively. There are, however, two very different competing versions of the formula for the spin angular momentum, one based on the use of the Poynting vector, as in classical electrodynamics, the other related to the canonical expression for the angular momentum which occurs in Quantum Electrodynamics. I analyze the possibility that a sufficiently sensitive optical measurement could decide which of these corresponds to the actual physical angular momentum carried by the beam.

High density nitrogen-vacancy sensing surface created via He{sup +} ion implantation of {sup 12}C diamond

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kleinsasser, Ed E., E-mail: edklein@uw.edu; Stanfield, Matthew M.; Banks, Jannel K. Q.

2016-05-16

We present a promising method for creating high-density ensembles of nitrogen-vacancy centers with narrow spin-resonances for high-sensitivity magnetic imaging. Practically, narrow spin-resonance linewidths substantially reduce the optical and RF power requirements for ensemble-based sensing. The method combines isotope purified diamond growth, in situ nitrogen doping, and helium ion implantation to realize a 100 nm-thick sensing surface. The obtained 10{sup 17 }cm{sup −3} nitrogen-vacancy density is only a factor of 10 less than the highest densities reported to date, with an observed 200 kHz spin resonance linewidth over 10 times narrower.

Optimization of transversal relaxation of nitroxides for pulsed electron-electron double resonance spectroscopy in phospholipid membranes.

PubMed

Dastvan, Reza; Bode, Bela E; Karuppiah, Muruga Poopathi Raja; Marko, Andriy; Lyubenova, Sevdalina; Schwalbe, Harald; Prisner, Thomas F

2010-10-28

Pulsed electron-electron double resonance (PELDOR) spectroscopy is increasingly applied to spin-labeled membrane proteins. However, after reconstitution into liposomes, spin labels often exhibit a much faster transversal relaxation (T(m)) than in detergent micelles, thus limiting application of the method in lipid bilayers. In this study, the main reasons for enhanced transversal relaxation in phospholipid membranes were investigated systematically by use of spin-labeled derivatives of stearic acid and phosphatidylcholine as well as spin-labeled derivatives of the channel-forming peptide gramicidin A under the conditions typically employed for PELDOR distance measurements. Our results clearly show that dephasing due to instantaneous diffusion that depends on dipolar interaction among electron spins is an important contributor to the fast echo decay in cases of high local concentrations of spin labels in membranes. The main difference between spin labels in detergent micelles and membranes is their local concentration. Consequently, avoiding spin clustering and suppressing instantaneous diffusion is the key step for maximizing PELDOR sensitivity in lipid membranes. Even though proton spin diffusion is an important relaxation mechanism, only in samples of low local concentrations does deuteration of acyl chains and buffer significantly prolong T(m). In these cases, values of up to 7 μs have been achieved. Furthermore, our study revealed that membrane composition and labeling position in the membrane can also affect T(m), either by promoting the segregation of spin-labeled species or by altering their exposure to matrix protons. Effects of other experimental parameters including temperature (<50 K), presence of oxygen, and cryoprotectant type are negligible under our experimental conditions.

Azimuthal transverse single-spin asymmetries of inclusive jets and charged pions within jets from polarized-proton collisions at √{s }=500 GeV

NASA Astrophysics Data System (ADS)

Adamczyk, L.; Adams, J. R.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Ajitanand, N. N.; Alekseev, I.; Anderson, D. M.; Aoyama, R.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Ashraf, M. U.; Attri, A.; Averichev, G. S.; Bai, X.; Bairathi, V.; Barish, K.; Behera, A.; Bellwied, R.; Bhasin, A.; Bhati, A. K.; Bhattarai, P.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bordyuzhin, I. G.; Bouchet, J.; Brandenburg, J. D.; Brandin, A. V.; Brown, D.; Bryslawskyj, J.; Bunzarov, I.; Butterworth, J.; Caines, H.; Calderón de la Barca Sánchez, M.; Campbell, J. M.; Cebra, D.; Chakaberia, I.; Chaloupka, P.; Chang, Z.; Chankova-Bunzarova, N.; Chatterjee, A.; Chattopadhyay, S.; Chen, X.; Chen, X.; Chen, J. H.; Cheng, J.; Cherney, M.; Christie, W.; Contin, G.; Crawford, H. J.; Das, S.; Dedovich, T. G.; Deng, J.; Deppner, I. M.; Derevschikov, A. A.; Didenko, L.; Dilks, C.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Dunlop, J. C.; Efimov, L. G.; Elsey, N.; Engelage, J.; Eppley, G.; Esha, R.; Esumi, S.; Evdokimov, O.; Ewigleben, J.; Eyser, O.; Fatemi, R.; Fazio, S.; Federic, P.; Federicova, P.; Fedorisin, J.; Feng, Z.; Filip, P.; Finch, E.; Fisyak, Y.; Flores, C. E.; Fujita, J.; Fulek, L.; Gagliardi, C. A.; Geurts, F.; Gibson, A.; Girard, M.; Grosnick, D.; Gunarathne, D. S.; Guo, Y.; Gupta, A.; Guryn, W.; Hamad, A. I.; Hamed, A.; Harlenderova, A.; Harris, J. W.; He, L.; Heppelmann, S.; Heppelmann, S.; Herrmann, N.; Hirsch, A.; Horvat, S.; Huang, B.; Huang, T.; Huang, X.; Huang, H. Z.; Humanic, T. J.; Huo, P.; Igo, G.; Jacobs, W. W.; Jentsch, A.; Jia, J.; Jiang, K.; Jowzaee, S.; Judd, E. G.; Kabana, S.; Kalinkin, D.; Kang, K.; Kapukchyan, D.; Kauder, K.; Ke, H. W.; Keane, D.; Kechechyan, A.; Khan, Z.; Kikoła, D. P.; Kim, C.; Kisel, I.; Kisiel, A.; Kochenda, L.; Kocmanek, M.; Kollegger, T.; Kosarzewski, L. K.; Kraishan, A. F.; Krauth, L.; Kravtsov, P.; Krueger, K.; Kulathunga, N.; Kumar, L.; Kvapil, J.; Kwasizur, J. H.; Lacey, R.; Landgraf, J. M.; Landry, K. D.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; Li, X.; Li, W.; Li, Y.; Li, C.; Lidrych, J.; Lin, T.; Lisa, M. A.; Liu, F.; Liu, P.; Liu, Y.; Liu, H.; Ljubicic, T.; Llope, W. J.; Lomnitz, M.; Longacre, R. S.; Luo, X.; Luo, S.; Ma, G. L.; Ma, L.; Ma, R.; Ma, Y. G.; Magdy, N.; Majka, R.; Mallick, D.; Margetis, S.; Markert, C.; Matis, H. S.; Mayes, D.; Meehan, K.; Mei, J. C.; Miller, Z. W.; Minaev, N. G.; Mioduszewski, S.; Mishra, D.; Mizuno, S.; Mohanty, B.; Mondal, M. M.; Morozov, D. A.; Mustafa, M. K.; Nasim, Md.; Nayak, T. K.; Nelson, J. M.; Nemes, D. B.; Nie, M.; Nigmatkulov, G.; Niida, T.; Nogach, L. V.; Nonaka, T.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Oh, K.; Okorokov, V. A.; Olvitt, D.; Page, B. S.; Pak, R.; Pandit, Y.; Panebratsev, Y.; Pawlik, B.; Pei, H.; Perkins, C.; Pluta, J.; Poniatowska, K.; Porter, J.; Posik, M.; Pruthi, N. K.; Przybycien, M.; Putschke, J.; Quintero, A.; Ramachandran, S.; Ray, R. L.; Reed, R.; Rehbein, M. J.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Roth, J. D.; Ruan, L.; Rusnak, J.; Rusnakova, O.; Sahoo, N. R.; Sahu, P. K.; Salur, S.; Sandweiss, J.; Saur, M.; Schambach, J.; Schmah, A. M.; Schmidke, W. B.; Schmitz, N.; Schweid, B. R.; Seger, J.; Sergeeva, M.; Seto, R.; Seyboth, P.; Shah, N.; Shahaliev, E.; Shanmuganathan, P. V.; Shao, M.; Shen, W. Q.; Shi, S. S.; Shi, Z.; Shou, Q. Y.; Sichtermann, E. P.; Sikora, R.; Simko, M.; Singha, S.; Skoby, M. J.; Smirnov, N.; Smirnov, D.; Solyst, W.; Sorensen, P.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Stewart, D. J.; Strikhanov, M.; Stringfellow, B.; Suaide, A. A. P.; Sugiura, T.; Sumbera, M.; Summa, B.; Sun, Y.; Sun, X.; Sun, X. M.; Surrow, B.; Svirida, D. N.; Tang, A. H.; Tang, Z.; Taranenko, A.; Tarnowsky, T.; Tawfik, A.; Thäder, J.; Thomas, J. H.; Timmins, A. R.; Tlusty, D.; Todoroki, T.; Tokarev, M.; Trentalange, S.; Tribble, R. E.; Tribedy, P.; Tripathy, S. K.; Trzeciak, B. A.; Tsai, O. D.; Ullrich, T.; Underwood, D. G.; Upsal, I.; Van Buren, G.; van Nieuwenhuizen, G.; Vasiliev, A. N.; Videbæk, F.; Vokal, S.; Voloshin, S. A.; Vossen, A.; Wang, G.; Wang, Y.; Wang, F.; Wang, Y.; Webb, G.; Webb, J. C.; Wen, L.; Westfall, G. D.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y.; Xiao, Z. G.; Xie, G.; Xie, W.; Xu, Y. F.; Xu, J.; Xu, Q. H.; Xu, N.; Xu, Z.; Yang, S.; Yang, Y.; Yang, C.; Yang, Q.; Ye, Z.; Ye, Z.; Yi, L.; Yip, K.; Yoo, I.-K.; Yu, N.; Zbroszczyk, H.; Zha, W.; Zhang, Z.; Zhang, J.; Zhang, S.; Zhang, S.; Zhang, J.; Zhang, Y.; Zhang, X. P.; Zhang, J. B.; Zhao, J.; Zhong, C.; Zhou, L.; Zhou, C.; Zhu, X.; Zhu, Z.; Zyzak, M.; STAR Collaboration

2018-02-01

We report the first measurements of transverse single-spin asymmetries for inclusive jet and jet+π± production at midrapidity from transversely polarized proton-proton collisions at √{s }=500 GeV . The data were collected in 2011 with the STAR detector sampled from 23 pb-1 integrated luminosity with an average beam polarization of 53%. Asymmetries are reported for jets with transverse momenta 6

Quantum Spin Gyroscope

DTIC Science & Technology

2015-07-15

performing optically detected CW ESR and on-resonance Rabi nutation of the elec- tronic spins (see figure 5). We observed increased homogeneity (as...different crystal axes. Here the magnetic field applied was ∼ 100G. Right: Rabi nutations 2.3 Sensitivity In order to test the performance of this first...resonant driving, which are strongly dependent on the hyperfine interaction. 5 Fig. 6: 14N Rabi oscillations at B = 450G, B1 ≈ 3.3G in the three NV

Computational models for the berry phase in semiconductor quantum dots

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prabhakar, S., E-mail: rmelnik@wlu.ca; Melnik, R. V. N., E-mail: rmelnik@wlu.ca; Sebetci, A.

2014-10-06

By developing a new model and its finite element implementation, we analyze the Berry phase low-dimensional semiconductor nanostructures, focusing on quantum dots (QDs). In particular, we solve the Schrödinger equation and investigate the evolution of the spin dynamics during the adiabatic transport of the QDs in the 2D plane along circular trajectory. Based on this study, we reveal that the Berry phase is highly sensitive to the Rashba and Dresselhaus spin-orbit lengths.

3D GRASE PROPELLER: improved image acquisition technique for arterial spin labeling perfusion imaging.

PubMed

Tan, Huan; Hoge, W Scott; Hamilton, Craig A; Günther, Matthias; Kraft, Robert A

2011-07-01

Arterial spin labeling is a noninvasive technique that can quantitatively measure cerebral blood flow. While traditionally arterial spin labeling employs 2D echo planar imaging or spiral acquisition trajectories, single-shot 3D gradient echo and spin echo (GRASE) is gaining popularity in arterial spin labeling due to inherent signal-to-noise ratio advantage and spatial coverage. However, a major limitation of 3D GRASE is through-plane blurring caused by T(2) decay. A novel technique combining 3D GRASE and a periodically rotated overlapping parallel lines with enhanced reconstruction trajectory (PROPELLER) is presented to minimize through-plane blurring without sacrificing perfusion sensitivity or increasing total scan time. Full brain perfusion images were acquired at a 3 × 3 × 5 mm(3) nominal voxel size with pulsed arterial spin labeling preparation sequence. Data from five healthy subjects was acquired on a GE 1.5T scanner in less than 4 minutes per subject. While showing good agreement in cerebral blood flow quantification with 3D gradient echo and spin echo, 3D GRASE PROPELLER demonstrated reduced through-plane blurring, improved anatomical details, high repeatability and robustness against motion, making it suitable for routine clinical use. Copyright © 2011 Wiley-Liss, Inc.

Setting the magic angle for fast magic-angle spinning probes.

PubMed

Penzel, Susanne; Smith, Albert A; Ernst, Matthias; Meier, Beat H

2018-06-15

Fast magic-angle spinning, coupled with 1 H detection is a powerful method to improve spectral resolution and signal to noise in solid-state NMR spectra. Commercial probes now provide spinning frequencies in excess of 100 kHz. Then, one has sufficient resolution in the 1 H dimension to directly detect protons, which have a gyromagnetic ratio approximately four times larger than 13 C spins. However, the gains in sensitivity can quickly be lost if the rotation angle is not set precisely. The most common method of magic-angle calibration is to optimize the number of rotary echoes, or sideband intensity, observed on a sample of KBr. However, this typically uses relatively low spinning frequencies, where the spinning of fast-MAS probes is often unstable, and detection on the 13 C channel, for which fast-MAS probes are typically not optimized. Therefore, we compare the KBr-based optimization of the magic angle with two alternative approaches: optimization of the splitting observed in 13 C-labeled glycine-ethylester on the carbonyl due to the Cα-C' J-coupling, or optimization of the H-N J-coupling spin echo in the protein sample itself. The latter method has the particular advantage that no separate sample is necessary for the magic-angle optimization. Copyright © 2018. Published by Elsevier Inc.

Low-Temperature Dynamic Nuclear Polarization at 9.4 Tesla With a 30 Milliwatt Microwave Source

PubMed Central

Thurber, Kent R.; Yau, Wai-Ming; Tycko, Robert

2010-01-01

Dynamic nuclear polarization (DNP) can provide large signal enhancements in nuclear magnetic resonance (NMR) by transfer of polarization from electron spins to nuclear spins. We discuss several aspects of DNP experiments at 9.4 Tesla (400 MHz resonant frequency for 1H, 264 GHz for electron spins in organic radicals) in the 7–80 K temperature range, using a 30 mW, frequency-tunable microwave source and a quasi-optical microwave bridge for polarization control and low-loss microwave transmission. In experiments on frozen glycerol/water doped with nitroxide radicals, DNP signal enhancements up to a factor of 80 are observed (relative to 1H NMR signals with thermal equilibrium spin polarization). The largest sensitivity enhancements are observed with a new triradical dopant, DOTOPA-TEMPO. Field modulation with a 10 G root-mean-squared amplitude during DNP increases the nuclear spin polarizations by up to 135%. Dependencies of 1H NMR signal amplitudes, nuclear spin relaxation times, and DNP build-up times on the dopant and its concentration, temperature, microwave power, and modulation frequency are reported and discussed. The benefits of low-temperature DNP can be dramatic: the 1H spin polarization is increased approximately 1000-fold at 7 K with DNP, relative to thermal polarization at 80 K. PMID:20392658

"Spin-dependent" \\varvec{μ → e} conversion on light nuclei

NASA Astrophysics Data System (ADS)

Davidson, Sacha; Kuno, Yoshitaka; Saporta, Albert

2018-02-01

The experimental sensitivity to μ → e conversion will improve by four or more orders of magnitude in coming years, making it interesting to consider the "spin-dependent" (SD) contribution to the rate. This process does not benefit from the atomic-number-squared enhancement of the spin-independent (SI) contribution, but probes different operators. We give details of our recent estimate of the spin-dependent rate, expressed as a function of operator coefficients at the experimental scale. Then we explore the prospects for distinguishing coefficients or models by using different targets, both in an EFT perspective, where a geometric representation of different targets as vectors in coefficient space is introduced, and also in three leptoquark models. It is found that comparing the rate on isotopes with and without spin could allow one to detect spin-dependent coefficients that are at least a factor of few larger than the spin-independent ones. Distinguishing among the axial, tensor and pseudoscalar operators that induce the SD rate would require calculating the nuclear matrix elements for the second two. Comparing the SD rate on nuclei with an odd proton vs. odd neutron could allow one to distinguish operators involving u quarks from those involving d quarks; this is interesting because the distinction is difficult to make for SI operators.

Coherent pump pulses in Double Electron Electron Resonance Spectroscopy

PubMed Central

Tait, Claudia E.; Stoll, Stefan

2016-01-01

The recent introduction of shaped pulses to Double Electron Electron Resonance (DEER) spectroscopy has led to significant enhancements in sensitivity through increased excitation bandwidths and improved control over spin dynamics. The application of DEER has so far relied on the presence of an incoherent pump channel to average out most undesired coherent effects of the pump pulse(s) on the observer spins. However, in fully coherent EPR spectrometers that are increasingly used to generate shaped pulses, the presence of coherent pump pulses means that these effects need to be explicitly considered. In this paper, we examine the effects of coherent rectangular and sech/tanh pump pulses in DEER experiments with up to three pump pulses. We show that, even in the absence of significant overlap of the observer and pump pulse excitation bandwidths, coherence transfer pathways involving both types of pulses generate spin echoes of considerable intensity. These echoes introduce artefacts, which, if not identified and removed, can easily lead to misinterpretation. We demonstrate that the observed echoes can be quantitatively modelled using a simple spin quantum dynamics approach that includes instrumental transfer functions. Based on an analysis of the echo crossing artefacts, we propose efficient phase cycling schemes for their suppression. This enables the use of advanced DEER experiments, characterized by high sensitivity and increased accuracy for long-distance measurements, on novel fully coherent EPR spectrometers. PMID:27339858

Ultrafast spintronics roadmap: from femtosecond spin current pulses to terahertz non-uniform spin dynamics via nano-confined spin transfer torques (Conference Presentation)

NASA Astrophysics Data System (ADS)

Melnikov, Alexey; Razdolski, Ilya; Alekhin, Alexandr; Ilin, Nikita; Meyburg, Jan; Diesing, Detlef; Roddatis, Vladimir; Rungger, Ivan; Stamenova, Maria; Sanvito, Stefano; Bovensiepen, Uwe

2016-10-01

Further development of spintronics requires miniaturization and reduction of characteristic timescales of spin dynamics combining the nanometer spatial and femtosecond temporal ranges. These demands shift the focus of interest towards the fundamental open question of the interaction of femtosecond spin current (SC) pulses with a ferromagnet (FM). The spatio-temporal properties of the spin transfer torque (STT) exerted by ultrashort SC pulses on the FM open the time domain for studying STT fingerprint on spatially non-uniform magnetization dynamics. Using the sensitivity of magneto-induced second harmonic generation to SC, we develop technique for SC monitoring. With 20 fs resolution, we demonstrate the generation of 250 fs-long SC pulses in Fe/Au/Fe/MgO(001) structures. Their temporal profile indicates (i) nearly-ballistic hot electron transport in Au and (ii) that the pulse duration is primarily determined by the thermalization time of laser-excited hot carriers in Fe. Together with strongly spin-dependent Fe/Au interface transmission calculated for these carriers, this suggests the non-thermal spin-dependent Seebeck effect dominating the generation of ultrashort SC pulses. The analysis of SC transmission/reflection at the Au/Fe interface shows that hot electron spins orthogonal to the Fe magnetization rotate gaining huge parallel (anti-parallel) projection in transmitted (reflected) SC. This is accompanied by a STT-induced perturbation of the magnetization localized at the interface, which excites the inhomogeneous high-frequency spin dynamics in the FM. Time-resolved magneto-optical studies reveal the excitation of several standing spin wave modes in the Fe film with their spectrum extending up to 0.6 THz and indicating the STT spatial confinement to 2 nm.

Domain wall dynamics driven by spin transfer torque and the spin-orbit field.

PubMed

Hayashi, Masamitsu; Nakatani, Yoshinobu; Fukami, Shunsuke; Yamanouchi, Michihiko; Mitani, Seiji; Ohno, Hideo

2012-01-18

We have studied current-driven dynamics of domain walls when an in-plane magnetic field is present in perpendicularly magnetized nanowires using an analytical model and micromagnetic simulations. We model an experimentally studied system, ultrathin magnetic nanowires with perpendicular anisotropy, where an effective in-plane magnetic field is developed when current is passed along the nanowire due to the Rashba-like spin-orbit coupling. Using a one-dimensional model of a domain wall together with micromagnetic simulations, we show that the existence of such in-plane magnetic fields can either lower or raise the threshold current needed to cause domain wall motion. In the presence of the in-plane field, the threshold current differs for positive and negative currents for a given wall chirality, and the wall motion becomes sensitive to out-of-plane magnetic fields. We show that large non-adiabatic spin torque can counteract the effect of the in-plane field.

Topological Hall and Spin Hall Effects in Disordered Skyrmionic Textures

NASA Astrophysics Data System (ADS)

Ndiaye, Papa Birame; Akosa, Collins; Manchon, Aurelien; Spintronics Theory Group Team

We carry out a throughout study of the topological Hall and topological spin Hall effects in disordered skyrmionic systems: the dimensionless (spin) Hall angles are evaluated across the energy band structure in the multiprobe Landauer-Büttiker formalism and their link to the effective magnetic field emerging from the real space topology of the spin texture is highlighted. We discuss these results for an optimal skyrmion size and for various sizes of the sample and found that the adiabatic approximation still holds for large skyrmions as well as for few atomic size-nanoskyrmions. Finally, we test the robustness of the topological signals against disorder strength and show that topological Hall effect is highly sensitive to momentum scattering. This work was supported by the King Abdullah University of Science and Technology (KAUST) through the Award No OSR-CRG URF/1/1693-01 from the Office of Sponsored Research (OSR).

Polarization transfer NMR imaging

DOEpatents

Sillerud, Laurel O.; van Hulsteyn, David B.

1990-01-01

A nuclear magnetic resonance (NMR) image is obtained with spatial information modulated by chemical information. The modulation is obtained through polarization transfer from a first element representing the desired chemical, or functional, information, which is covalently bonded and spin-spin coupled with a second element effective to provide the imaging data. First and second rf pulses are provided at first and second frequencies for exciting the imaging and functional elements, with imaging gradients applied therebetween to spatially separate the nuclei response for imaging. The second rf pulse is applied at a time after the first pulse which is the inverse of the spin coupling constant to select the transfer element nuclei which are spin coupled to the functional element nuclei for imaging. In a particular application, compounds such as glucose, lactate, or lactose, can be labeled with .sup.13 C and metabolic processes involving the compounds can be imaged with the sensitivity of .sup.1 H and the selectivity of .sup.13 C.

Direct enhancement of nitrogen-15 targets at high-field by fast ADAPT-SABRE

NASA Astrophysics Data System (ADS)

Roy, Soumya S.; Stevanato, Gabriele; Rayner, Peter J.; Duckett, Simon B.

2017-12-01

Signal Amplification by Reversible Exchange (SABRE) is an attractive nuclear spin hyperpolarization technique capable of huge sensitivity enhancement in nuclear magnetic resonance (NMR) detection. The resonance condition of SABRE hyperpolarization depends on coherent spin mixing, which can be achieved naturally at a low magnetic field. The optimum transfer field to spin-1/2 heteronuclei is technically demanding, as it requires field strengths weaker than the earth's magnetic field for efficient spin mixing. In this paper, we illustrate an approach to achieve strong 15N SABRE hyperpolarization at high magnetic field by a radio frequency (RF) driven coherent transfer mechanism based on alternate pulsing and delay to achieve polarization transfer. The presented scheme is found to be highly robust and much faster than existing related methods, producing ∼ 3 orders of magnitude 15N signal enhancement within 2 s of RF pulsing.

Direct enhancement of nitrogen-15 targets at high-field by fast ADAPT-SABRE.

PubMed

Roy, Soumya S; Stevanato, Gabriele; Rayner, Peter J; Duckett, Simon B

2017-12-01

Signal Amplification by Reversible Exchange (SABRE) is an attractive nuclear spin hyperpolarization technique capable of huge sensitivity enhancement in nuclear magnetic resonance (NMR) detection. The resonance condition of SABRE hyperpolarization depends on coherent spin mixing, which can be achieved naturally at a low magnetic field. The optimum transfer field to spin-1/2 heteronuclei is technically demanding, as it requires field strengths weaker than the earth's magnetic field for efficient spin mixing. In this paper, we illustrate an approach to achieve strong 15 N SABRE hyperpolarization at high magnetic field by a radio frequency (RF) driven coherent transfer mechanism based on alternate pulsing and delay to achieve polarization transfer. The presented scheme is found to be highly robust and much faster than existing related methods, producing ∼3 orders of magnitude 15 N signal enhancement within 2 s of RF pulsing. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Transverse single-spin asymmetries for direct photon and neutral pion production in midrapidity at PHENIX

NASA Astrophysics Data System (ADS)

Lewis, Nicole; Phenix Collaboration

2017-09-01

Large transverse single spin asymmetries for hadron production in proton-proton collisions were some of the first indicators of significant nonperturbative spin-momentum correlations in the proton. They have been found to persist up to collision energies of 510 GeV, yet their origin remains poorly understood. Measurements of different final-state particles in a wide variety of collision systems over a range of kinematics can help to identify and separate contributions from the proton versus hadronization, and from different parton flavors. Depending on the rapidity pion production can provide access to both initial- and final-state effects for a mix of parton flavors, while direct photons depend only on initial-state effects and are particularly sensitive to gluon dynamics in RHIC kinematics. The status of transverse single spin measurements for neutral pions and direct photons performed for p+p, p+Al, and p+Au collisions at PHENIX will be presented.

Magnetoresistance in Permalloy Connected Brickwork Artificial Spin Ice

NASA Astrophysics Data System (ADS)

Park, Jungsik; Le, Brian; Chern, Gia-Wei; Watts, Justin; Leighton, Chris; Schiffer, Peter

Artificial spin ice refers to a two-dimensional array of elongated ferromagnetic elements in which frustrated lattice geometry induces novel magnetic behavior. Here we examine room-temperature magnetoresistance properties of connected permalloy (Ni81Fe19) brickwork artificial spin ice. Both the longitudinal and transverse magnetoresistance of the nanostructure demonstrate an angular sensitivity that has not been previously observed. The observed magnetoresistance behavior can be explained from micromagnetic modelling using an anisotropic magnetoresistance model (AMR). As part of this study, we find that the ground state of the connected brickwork artificial spin ice can be reproducibly created by a simple field sweep in a narrow range of angles, and manifests in the magnetotransport with a distinct signal. Supported by the US Department of Energy, Office of Basic Energy Sciences, Materials Sciences and Engineering Division under Grant Number DE-SC0010778. Work at the University of Minnesota was supported by the NSF MRSEC under award DMR-1420013, and DMR-1507048.

Quantum interference effect in electron tunneling through a quantum-dot-ring spin valve

PubMed Central

2011-01-01

Spin-dependent transport through a quantum-dot (QD) ring coupled to ferromagnetic leads with noncollinear magnetizations is studied theoretically. Tunneling current, current spin polarization and tunnel magnetoresistance (TMR) as functions of the bias voltage and the direct coupling strength between the two leads are analyzed by the nonequilibrium Green's function technique. It is shown that the magnitudes of these quantities are sensitive to the relative angle between the leads' magnetic moments and the quantum interference effect originated from the inter-lead coupling. We pay particular attention on the Coulomb blockade regime and find the relative current magnitudes of different magnetization angles can be reversed by tuning the inter-lead coupling strength, resulting in sign change of the TMR. For large enough inter-lead coupling strength, the current spin polarizations for parallel and antiparallel magnetic configurations will approach to unit and zero, respectively. PACS numbers: PMID:21711779

Reduction of shunt current in buffer-free IrMn based spin-valve structures

NASA Astrophysics Data System (ADS)

Kocaman, B.; Akdoğan, N.

2018-06-01

The presence of thick buffer layers in magnetic sensor devices decreases sensor sensitivity due to shunt currents. With this motivation, we produced IrMn-based spin-valve multilayers without using buffer layer. We also studied the effects of post-annealing and IrMn thickness on exchange bias field (HEB) and blocking temperature (TB) of the system. Magnetization measurements indicate that both HEB and TB values are significantly enhanced with post-annealing of IrMn layer. In addition, we report that IrMn thickness of the system strongly influences the magnetization and transport characteristics of the spin-valve structures. We found that the minimum thickness of IrMn layer is 6 nm in order to achieve the lowest shunt current and high blocking temperature (>300 K). We also investigated the training of exchange bias to check the long-term durability of IrMn-based spin-valve structures for device applications.

Multi-dimensional single-spin nano-optomechanics with a levitated nanodiamond

NASA Astrophysics Data System (ADS)

Neukirch, Levi P.; von Haartman, Eva; Rosenholm, Jessica M.; Nick Vamivakas, A.

2015-10-01

Considerable advances made in the development of nanomechanical and nano-optomechanical devices have enabled the observation of quantum effects, improved sensitivity to minute forces, and provided avenues to probe fundamental physics at the nanoscale. Concurrently, solid-state quantum emitters with optically accessible spin degrees of freedom have been pursued in applications ranging from quantum information science to nanoscale sensing. Here, we demonstrate a hybrid nano-optomechanical system composed of a nanodiamond (containing a single nitrogen-vacancy centre) that is levitated in an optical dipole trap. The mechanical state of the diamond is controlled by modulation of the optical trapping potential. We demonstrate the ability to imprint the multi-dimensional mechanical motion of the cavity-free mechanical oscillator into the nitrogen-vacancy centre fluorescence and manipulate the mechanical system's intrinsic spin. This result represents the first step towards a hybrid quantum system based on levitating nanoparticles that simultaneously engages optical, phononic and spin degrees of freedom.

Influence of the iron spin crossover in ferropericlase on the lower mantle geotherm

NASA Astrophysics Data System (ADS)

Valencia-Cardona, Juan J.; Shukla, Gaurav; Wu, Zhongqing; Houser, Christine; Yuen, David A.; Wentzcovitch, Renata M.

2017-05-01

The iron spin crossover in ferropericlase introduces anomalies in its thermodynamics and thermoelastic properties. Here we investigate how these anomalies can affect the lower mantle geotherm using thermodynamics properties from ab initio calculations. The anomalous effect is examined in mantle aggregates consisting of mixtures of bridgmanite, ferropericlase, and CaSiO3 perovskite, with different Mg/Si ratios varying from harzburgitic to perovskitic (Mg/Si ˜ 1.5 to 0.8). We find that the anomalies introduced by the spin crossover increase the isentropic gradient and thus the geotherm proportionally to the amount of ferropericlase. The geotherms can be as much as ˜200 K hotter than the conventional adiabatic geotherm at deep lower mantle conditions. Aggregate elastic moduli and seismic velocities are also sensitive to the spin crossover and the geotherm, which impacts analyses of lower mantle velocities and composition.

Theory of triplet-triplet annihilation in optically detected magnetic resonance

NASA Astrophysics Data System (ADS)

Keevers, T. L.; McCamey, D. R.

2016-01-01

Triplet-triplet annihilation allows two low-energy photons to be upconverted into a single high-energy photon. By essentially engineering the solar spectrum, this allows solar cells to be made more efficient and even exceed the Shockley-Quiesser limit. Unfortunately, optimizing the reaction pathway is difficult, especially with limited access to the microscopic time scales and states involved in the process. Optical measurements can provide detailed information: triplet-triplet annihilation is intrinsically spin dependent and exhibits substantial magnetoluminescence in the presence of a static magnetic field. Pulsed optically detected magnetic resonance is especially suitable, since it combines high spin sensitivity with coherent manipulation. In this paper, we develop a time-domain theory of triplet-triplet annihilation for complexes with arbitrary spin-spin coupling. We identify unique "Rabi fingerprints" for each coupling regime and show that this can be used to characterize the microscopic Hamiltonian.

Spin-torque diode with tunable sensitivity and bandwidth by out-of-plane magnetic field

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, X.; Zheng, C.; Pong, Philip W. T.

Spin-torque diodes based on nanosized magnetic tunnel junctions are novel microwave detectors with high sensitivity and wide frequency bandwidth. While previous reports mainly focus on improving the sensitivity, the approaches to extend the bandwidth are limited. This work experimentally demonstrates that through optimizing the orientation of the external magnetic field, wide bandwidth can be achieved while maintaining high sensitivity. The mechanism of the frequency- and sensitivity-tuning is investigated through analyzing the dependence of resonant frequency and DC voltage on the magnitude and the tilt angle of hard-plane magnetic field. The frequency dependence is qualitatively explicated by Kittel's ferromagnetic resonance model.more » The asymmetric resonant frequency at positive and negative magnetic field is verified by the numerical simulation considering the in-plane anisotropy. The DC voltage dependence is interpreted through evaluating the misalignment angle between the magnetization of the free layer and the reference layer. The tunability of the detector performance by the magnetic field angle is evaluated through characterizing the sensitivity and bandwidth under 3D magnetic field. The frequency bandwidth up to 9.8 GHz or maximum sensitivity up to 154 mV/mW (after impedance mismatch correction) can be achieved by tuning the angle of the applied magnetic field. The results show that the bandwidth and sensitivity can be controlled and adjusted through optimizing the orientation of the magnetic field for various applications and requirements.« less

Magnon Splitting Induced by Charge Transfer in the Three-Orbital Hubbard Model

NASA Astrophysics Data System (ADS)

Wang, Yao; Huang, Edwin W.; Moritz, Brian; Devereaux, Thomas P.

2018-06-01

Understanding spin excitations and their connection to unconventional superconductivity have remained central issues since the discovery of cuprates. Direct measurement of the dynamical spin structure factor in the parent compounds can provide key information on important interactions relevant in the doped regime, and variations in the magnon dispersion have been linked closely to differences in crystal structure between families of cuprate compounds. Here, we elucidate the relationship between spin excitations and various controlling factors thought to be significant in high-Tc materials by systematically evaluating the dynamical spin structure factor for the three-orbital Hubbard model, revealing differences in the spin dispersion along the Brillouin zone axis and the diagonal. Generally, we find that the absolute energy scale and momentum dependence of the excitations primarily are sensitive to the effective charge-transfer energy, while changes in the on-site Coulomb interactions have little effect on the details of the dispersion. In particular, our result highlights the splitting between spin excitations along the axial and diagonal directions in the Brillouin zone. This splitting decreases with increasing charge-transfer energy and correlates with changes in the apical oxygen position, and general structural variations, for different cuprate families.

Study of the spin and parity of the Higgs boson in diboson decays with the ATLAS detector

NASA Astrophysics Data System (ADS)

Aad, G.; Abbott, B.; Abdallah, J.; Abdinov, O.; Aben, R.; Abolins, M.; AbouZeid, O. S.; Abramowicz, H.; Abreu, H.; Abreu, R.; Abulaiti, Y.; Acharya, B. S.; Adamczyk, L.; Adams, D. L.; Adelman, J.; Adomeit, S.; Adye, T.; Affolder, A. A.; Agatonovic-Jovin, T.; Agricola, J.; Aguilar-Saavedra, J. A.; Ahlen, S. P.; Ahmadov, F.; Aielli, G.; Akerstedt, H.; Åkesson, T. P. A.; Akimov, A. V.; Alberghi, G. L.; Albert, J.; Albrand, S.; Alconada Verzini, M. J.; Aleksa, M.; Aleksandrov, I. N.; Alexa, C.; Alexander, G.; Alexopoulos, T.; Alhroob, M.; Alimonti, G.; Alio, L.; Alison, J.; Alkire, S. P.; Allbrooke, B. M. M.; Allport, P. P.; Aloisio, A.; Alonso, A.; Alonso, F.; Alpigiani, C.; Altheimer, A.; Alvarez Gonzalez, B.; Álvarez Piqueras, D.; Alviggi, M. G.; Amadio, B. T.; Amako, K.; Amaral Coutinho, Y.; Amelung, C.; Amidei, D.; Amor Dos Santos, S. P.; Amorim, A.; Amoroso, S.; Amram, N.; Amundsen, G.; Anastopoulos, C.; Ancu, L. S.; Andari, N.; Andeen, T.; Anders, C. F.; Anders, G.; Anders, J. K.; Anderson, K. J.; Andreazza, A.; Andrei, V.; Angelidakis, S.; Angelozzi, I.; Anger, P.; Angerami, A.; Anghinolfi, F.; Anisenkov, A. V.; Anjos, N.; Annovi, A.; Antonelli, M.; Antonov, A.; Antos, J.; Anulli, F.; Aoki, M.; Aperio Bella, L.; Arabidze, G.; Arai, Y.; Araque, J. P.; Arce, A. T. H.; Arduh, F. A.; Arguin, J.-F.; Argyropoulos, S.; Arik, M.; Armbruster, A. J.; Arnaez, O.; Arnal, V.; Arnold, H.; Arratia, M.; Arslan, O.; Artamonov, A.; Artoni, G.; Asai, S.; Asbah, N.; Ashkenazi, A.; Åsman, B.; Asquith, L.; Assamagan, K.; Astalos, R.; Atkinson, M.; Atlay, N. B.; Auerbach, B.; Augsten, K.; Aurousseau, M.; Avolio, G.; Axen, B.; Ayoub, M. K.; Azuelos, G.; Baak, M. A.; Baas, A. E.; Bacci, C.; Bachacou, H.; Bachas, K.; Backes, M.; Backhaus, M.; Bagiacchi, P.; Bagnaia, P.; Bai, Y.; Bain, T.; Baines, J. T.; Baker, O. K.; Baldin, E. M.; Balek, P.; Balestri, T.; Balli, F.; Banas, E.; Banerjee, Sw.; Bannoura, A. A. E.; Bansil, H. S.; Barak, L.; Barberio, E. L.; Barberis, D.; Barbero, M.; Barillari, T.; Barisonzi, M.; Barklow, T.; Barlow, N.; Barnes, S. L.; Barnett, B. M.; Barnett, R. M.; Barnovska, Z.; Baroncelli, A.; Barone, G.; Barr, A. J.; Barreiro, F.; Barreiro Guimarães da Costa, J.; Bartoldus, R.; Barton, A. E.; Bartos, P.; Basalaev, A.; Bassalat, A.; Basye, A.; Bates, R. L.; Batista, S. J.; Batley, J. R.; Battaglia, M.; Bauce, M.; Bauer, F.; Bawa, H. S.; Beacham, J. B.; Beattie, M. D.; Beau, T.; Beauchemin, P. H.; Beccherle, R.; Bechtle, P.; Beck, H. P.; Becker, K.; Becker, M.; Becker, S.; Beckingham, M.; Becot, C.; Beddall, A. J.; Beddall, A.; Bednyakov, V. A.; Bee, C. P.; Beemster, L. J.; Beermann, T. A.; Begel, M.; Behr, J. K.; Belanger-Champagne, C.; Bell, W. H.; Bella, G.; Bellagamba, L.; Bellerive, A.; Bellomo, M.; Belotskiy, K.; Beltramello, O.; Benary, O.; Benchekroun, D.; Bender, M.; Bendtz, K.; Benekos, N.; Benhammou, Y.; Benhar Noccioli, E.; Benitez Garcia, J. A.; Benjamin, D. P.; Bensinger, J. R.; Bentvelsen, S.; Beresford, L.; Beretta, M.; Berge, D.; Bergeaas Kuutmann, E.; Berger, N.; Berghaus, F.; Beringer, J.; Bernard, C.; Bernard, N. R.; Bernius, C.; Bernlochner, F. U.; Berry, T.; Berta, P.; Bertella, C.; Bertoli, G.; Bertolucci, F.; Bertsche, C.; Bertsche, D.; Besana, M. I.; Besjes, G. J.; Bessidskaia Bylund, O.; Bessner, M.; Besson, N.; Betancourt, C.; Bethke, S.; Bevan, A. J.; Bhimji, W.; Bianchi, R. M.; Bianchini, L.; Bianco, M.; Biebel, O.; Biedermann, D.; Bieniek, S. P.; Biglietti, M.; Bilbao De Mendizabal, J.; Bilokon, H.; Bindi, M.; Binet, S.; Bingul, A.; Bini, C.; Biondi, S.; Black, C. W.; Black, J. E.; Black, K. M.; Blackburn, D.; Blair, R. E.; Blanchard, J.-B.; Blanco, J. E.; Blazek, T.; Bloch, I.; Blocker, C.; Blum, W.; Blumenschein, U.; Bobbink, G. J.; Bobrovnikov, V. S.; Bocchetta, S. S.; Bocci, A.; Bock, C.; Boehler, M.; Bogaerts, J. A.; Bogavac, D.; Bogdanchikov, A. G.; Bohm, C.; Boisvert, V.; Bold, T.; Boldea, V.; Boldyrev, A. S.; Bomben, M.; Bona, M.; Boonekamp, M.; Borisov, A.; Borissov, G.; Borroni, S.; Bortfeldt, J.; Bortolotto, V.; Bos, K.; Boscherini, D.; Bosman, M.; Boudreau, J.; Bouffard, J.; Bouhova-Thacker, E. V.; Boumediene, D.; Bourdarios, C.; Bousson, N.; Boveia, A.; Boyd, J.; Boyko, I. R.; Bozic, I.; Bracinik, J.; Brandt, A.; Brandt, G.; Brandt, O.; Bratzler, U.; Brau, B.; Brau, J. E.; Braun, H. M.; Brazzale, S. F.; Breaden Madden, W. D.; Brendlinger, K.; Brennan, A. J.; Brenner, L.; Brenner, R.; Bressler, S.; Bristow, K.; Bristow, T. M.; Britton, D.; Britzger, D.; Brochu, F. M.; Brock, I.; Brock, R.; Bronner, J.; Brooijmans, G.; Brooks, T.; Brooks, W. K.; Brosamer, J.; Brost, E.; Brown, J.; Bruckman de Renstrom, P. A.; Bruncko, D.; Bruneliere, R.; Bruni, A.; Bruni, G.; Bruschi, M.; Bruscino, N.; Bryngemark, L.; Buanes, T.; Buat, Q.; Buchholz, P.; Buckley, A. G.; Buda, S. I.; Budagov, I. A.; Buehrer, F.; Bugge, L.; Bugge, M. K.; Bulekov, O.; Bullock, D.; Burckhart, H.; Burdin, S.; Burghgrave, B.; Burke, S.; Burmeister, I.; Busato, E.; Büscher, D.; Büscher, V.; Bussey, P.; Butler, J. M.; Butt, A. I.; Buttar, C. M.; Butterworth, J. M.; Butti, P.; Buttinger, W.; Buzatu, A.; Buzykaev, A. R.; Cabrera Urbán, S.; Caforio, D.; Cairo, V. M.; Cakir, O.; Calafiura, P.; Calandri, A.; Calderini, G.; Calfayan, P.; Caloba, L. P.; Calvet, D.; Calvet, S.; Camacho Toro, R.; Camarda, S.; Camarri, P.; Cameron, D.; Caminal Armadans, R.; Campana, S.; Campanelli, M.; Campoverde, A.; Canale, V.; Canepa, A.; Cano Bret, M.; Cantero, J.; Cantrill, R.; Cao, T.; Capeans Garrido, M. D. M.; Caprini, I.; Caprini, M.; Capua, M.; Caputo, R.; Cardarelli, R.; Cardillo, F.; Carli, T.; Carlino, G.; Carminati, L.; Caron, S.; Carquin, E.; Carrillo-Montoya, G. D.; Carter, J. R.; Carvalho, J.; Casadei, D.; Casado, M. P.; Casolino, M.; Castaneda-Miranda, E.; Castelli, A.; Castillo Gimenez, V.; Castro, N. F.; Catastini, P.; Catinaccio, A.; Catmore, J. R.; Cattai, A.; Caudron, J.; Cavaliere, V.; Cavalli, D.; Cavalli-Sforza, M.; Cavasinni, V.; Ceradini, F.; Cerio, B. C.; Cerny, K.; Cerqueira, A. S.; Cerri, A.; Cerrito, L.; Cerutti, F.; Cerv, M.; Cervelli, A.; Cetin, S. A.; Chafaq, A.; Chakraborty, D.; Chalupkova, I.; Chang, P.; Chapman, J. D.; Charlton, D. G.; Chau, C. C.; Chavez Barajas, C. A.; Cheatham, S.; Chegwidden, A.; Chekanov, S.; Chekulaev, S. V.; Chelkov, G. A.; Chelstowska, M. A.; Chen, C.; Chen, H.; Chen, K.; Chen, L.; Chen, S.; Chen, X.; Chen, Y.; Cheng, H. C.; Cheng, Y.; Cheplakov, A.; Cheremushkina, E.; Cherkaoui El Moursli, R.; Chernyatin, V.; Cheu, E.; Chevalier, L.; Chiarella, V.; Childers, J. T.; Chiodini, G.; Chisholm, A. S.; Chislett, R. T.; Chitan, A.; Chizhov, M. V.; Choi, K.; Chouridou, S.; Chow, B. K. B.; Christodoulou, V.; Chromek-Burckhart, D.; Chudoba, J.; Chuinard, A. J.; Chwastowski, J. J.; Chytka, L.; Ciapetti, G.; Ciftci, A. K.; Cinca, D.; Cindro, V.; Cioara, I. A.; Ciocio, A.; Cirotto, F.; Citron, Z. H.; Ciubancan, M.; Clark, A.; Clark, B. L.; Clark, P. J.; Clarke, R. N.; Cleland, W.; Clement, C.; Coadou, Y.; Cobal, M.; Coccaro, A.; Cochran, J.; Coffey, L.; Cogan, J. G.; Cole, B.; Cole, S.; Colijn, A. P.; Collot, J.; Colombo, T.; Compostella, G.; Conde Muiño, P.; Coniavitis, E.; Connell, S. H.; Connelly, I. A.; Consonni, S. M.; Consorti, V.; Constantinescu, S.; Conta, C.; Conti, G.; Conventi, F.; Cooke, M.; Cooper, B. D.; Cooper-Sarkar, A. M.; Cornelissen, T.; Corradi, M.; Corriveau, F.; Corso-Radu, A.; Cortes-Gonzalez, A.; Cortiana, G.; Costa, G.; Costa, M. J.; Costanzo, D.; Côté, D.; Cottin, G.; Cowan, G.; Cox, B. E.; Cranmer, K.; Cree, G.; Crépé-Renaudin, S.; Crescioli, F.; Cribbs, W. A.; Crispin Ortuzar, M.; Cristinziani, M.; Croft, V.; Crosetti, G.; Cuhadar Donszelmann, T.; Cummings, J.; Curatolo, M.; Cuthbert, C.; Czirr, H.; Czodrowski, P.; D'Auria, S.; D'Onofrio, M.; Da Cunha Sargedas De Sousa, M. J.; Da Via, C.; Dabrowski, W.; Dafinca, A.; Dai, T.; Dale, O.; Dallaire, F.; Dallapiccola, C.; Dam, M.; Dandoy, J. R.; Dang, N. P.; Daniells, A. C.; Danninger, M.; Dano Hoffmann, M.; Dao, V.; Darbo, G.; Darmora, S.; Dassoulas, J.; Dattagupta, A.; Davey, W.; David, C.; Davidek, T.; Davies, E.; Davies, M.; Davison, P.; Davygora, Y.; Dawe, E.; Dawson, I.; Daya-Ishmukhametova, R. K.; De, K.; de Asmundis, R.; De Castro, S.; De Cecco, S.; De Groot, N.; de Jong, P.; De la Torre, H.; De Lorenzi, F.; De Nooij, L.; De Pedis, D.; De Salvo, A.; De Sanctis, U.; De Santo, A.; De Vivie De Regie, J. B.; Dearnaley, W. J.; Debbe, R.; Debenedetti, C.; Dedovich, D. V.; Deigaard, I.; Del Peso, J.; Del Prete, T.; Delgove, D.; Deliot, F.; Delitzsch, C. M.; Deliyergiyev, M.; Dell'Acqua, A.; Dell'Asta, L.; Dell'Orso, M.; Della Pietra, M.; della Volpe, D.; Delmastro, M.; Delsart, P. A.; Deluca, C.; DeMarco, D. A.; Demers, S.; Demichev, M.; Demilly, A.; Denisov, S. P.; Derendarz, D.; Derkaoui, J. E.; Derue, F.; Dervan, P.; Desch, K.; Deterre, C.; Deviveiros, P. O.; Dewhurst, A.; Dhaliwal, S.; Di Ciaccio, A.; Di Ciaccio, L.; Di Domenico, A.; Di Donato, C.; Di Girolamo, A.; Di Girolamo, B.; Di Mattia, A.; Di Micco, B.; Di Nardo, R.; Di Simone, A.; Di Sipio, R.; Di Valentino, D.; Diaconu, C.; Diamond, M.; Dias, F. A.; Diaz, M. A.; Diehl, E. B.; Dietrich, J.; Diglio, S.; Dimitrievska, A.; Dingfelder, J.; Dita, P.; Dita, S.; Dittus, F.; Djama, F.; Djobava, T.; Djuvsland, J. I.; do Vale, M. A. B.; Dobos, D.; Dobre, M.; Doglioni, C.; Dohmae, T.; Dolejsi, J.; Dolezal, Z.; Dolgoshein, B. A.; Donadelli, M.; Donati, S.; Dondero, P.; Donini, J.; Dopke, J.; Doria, A.; Dova, M. T.; Doyle, A. T.; Drechsler, E.; Dris, M.; Dubreuil, E.; Duchovni, E.; Duckeck, G.; Ducu, O. A.; Duda, D.; Dudarev, A.; Duflot, L.; Duguid, L.; Dührssen, M.; Dunford, M.; Duran Yildiz, H.; Düren, M.; Durglishvili, A.; Duschinger, D.; Dyndal, M.; Eckardt, C.; Ecker, K. M.; Edgar, R. C.; Edson, W.; Edwards, N. C.; Ehrenfeld, W.; Eifert, T.; Eigen, G.; Einsweiler, K.; Ekelof, T.; El Kacimi, M.; Ellert, M.; Elles, S.; Ellinghaus, F.; Elliot, A. A.; Ellis, N.; Elmsheuser, J.; Elsing, M.; Emeliyanov, D.; Enari, Y.; Endner, O. C.; Endo, M.; Erdmann, J.; Ereditato, A.; Ernis, G.; Ernst, J.; Ernst, M.; Errede, S.; Ertel, E.; Escalier, M.; Esch, H.; Escobar, C.; Esposito, B.; Etienvre, A. I.; Etzion, E.; Evans, H.; Ezhilov, A.; Fabbri, L.; Facini, G.; Fakhrutdinov, R. M.; Falciano, S.; Falla, R. J.; Faltova, J.; Fang, Y.; Fanti, M.; Farbin, A.; Farilla, A.; Farooque, T.; Farrell, S.; Farrington, S. M.; Farthouat, P.; Fassi, F.; Fassnacht, P.; Fassouliotis, D.; Faucci Giannelli, M.; Favareto, A.; Fayard, L.; Federic, P.; Fedin, O. L.; Fedorko, W.; Feigl, S.; Feligioni, L.; Feng, C.; Feng, E. J.; Feng, H.; Fenyuk, A. B.; Feremenga, L.; Fernandez Martinez, P.; Fernandez Perez, S.; Ferrando, J.; Ferrari, A.; Ferrari, P.; Ferrari, R.; Ferreira de Lima, D. E.; Ferrer, A.; Ferrere, D.; Ferretti, C.; Ferretto Parodi, A.; Fiascaris, M.; Fiedler, F.; Filipčič, A.; Filipuzzi, M.; Filthaut, F.; Fincke-Keeler, M.; Finelli, K. D.; Fiolhais, M. C. N.; Fiorini, L.; Firan, A.; Fischer, A.; Fischer, C.; Fischer, J.; Fisher, W. C.; Fitzgerald, E. A.; Flaschel, N.; Fleck, I.; Fleischmann, P.; Fleischmann, S.; Fletcher, G. T.; Fletcher, G.; Fletcher, R. R. M.; Flick, T.; Floderus, A.; Flores Castillo, L. R.; Flowerdew, M. J.; Formica, A.; Forti, A.; Fournier, D.; Fox, H.; Fracchia, S.; Francavilla, P.; Franchini, M.; Francis, D.; Franconi, L.; Franklin, M.; Frate, M.; Fraternali, M.; Freeborn, D.; French, S. T.; Friedrich, F.; Froidevaux, D.; Frost, J. A.; Fukunaga, C.; Fullana Torregrosa, E.; Fulsom, B. G.; Fuster, J.; Gabaldon, C.; Gabizon, O.; Gabrielli, A.; Gabrielli, A.; Gadatsch, S.; Gadomski, S.; Gagliardi, G.; Gagnon, P.; Galea, C.; Galhardo, B.; Gallas, E. J.; Gallop, B. J.; Gallus, P.; Galster, G.; Gan, K. K.; Gao, J.; Gao, Y.; Gao, Y. S.; Garay Walls, F. M.; Garberson, F.; García, C.; García Navarro, J. E.; Garcia-Sciveres, M.; Gardner, R. W.; Garelli, N.; Garonne, V.; Gatti, C.; Gaudiello, A.; Gaudio, G.; Gaur, B.; Gauthier, L.; Gauzzi, P.; Gavrilenko, I. L.; Gay, C.; Gaycken, G.; Gazis, E. N.; Ge, P.; Gecse, Z.; Gee, C. N. P.; Geerts, D. A. A.; Geich-Gimbel, Ch.; Geisler, M. P.; Gemme, C.; Genest, M. H.; Gentile, S.; George, M.; George, S.; Gerbaudo, D.; Gershon, A.; Ghasemi, S.; Ghazlane, H.; Giacobbe, B.; Giagu, S.; Giangiobbe, V.; Giannetti, P.; Gibbard, B.; Gibson, S. M.; Gilchriese, M.; Gillam, T. P. S.; Gillberg, D.; Gilles, G.; Gingrich, D. M.; Giokaris, N.; Giordani, M. P.; Giorgi, F. M.; Giorgi, F. M.; Giraud, P. F.; Giromini, P.; Giugni, D.; Giuliani, C.; Giulini, M.; Gjelsten, B. K.; Gkaitatzis, S.; Gkialas, I.; Gkougkousis, E. L.; Gladilin, L. K.; Glasman, C.; Glatzer, J.; Glaysher, P. C. F.; Glazov, A.; Goblirsch-Kolb, M.; Goddard, J. R.; Godlewski, J.; Goldfarb, S.; Golling, T.; Golubkov, D.; Gomes, A.; Gonçalo, R.; Goncalves Pinto Firmino Da Costa, J.; Gonella, L.; González de la Hoz, S.; Gonzalez Parra, G.; Gonzalez-Sevilla, S.; Goossens, L.; Gorbounov, P. A.; Gordon, H. A.; Gorelov, I.; Gorini, B.; Gorini, E.; Gorišek, A.; Gornicki, E.; Goshaw, A. T.; Gössling, C.; Gostkin, M. I.; Goujdami, D.; Goussiou, A. G.; Govender, N.; Gozani, E.; Grabas, H. M. X.; Graber, L.; Grabowska-Bold, I.; Grafström, P.; Grahn, K.-J.; Gramling, J.; Gramstad, E.; Grancagnolo, S.; Grassi, V.; Gratchev, V.; Gray, H. M.; Graziani, E.; Greenwood, Z. D.; Gregersen, K.; Gregor, I. M.; Grenier, P.; Griffiths, J.; Grillo, A. A.; Grimm, K.; Grinstein, S.; Gris, Ph.; Grivaz, J.-F.; Grohs, J. P.; Grohsjean, A.; Gross, E.; Grosse-Knetter, J.; Grossi, G. C.; Grout, Z. J.; Guan, L.; Guenther, J.; Guescini, F.; Guest, D.; Gueta, O.; Guido, E.; Guillemin, T.; Guindon, S.; Gul, U.; Gumpert, C.; Guo, J.; Guo, Y.; Gupta, S.; Gustavino, G.; Gutierrez, P.; Gutierrez Ortiz, N. G.; Gutschow, C.; Guyot, C.; Gwenlan, C.; Gwilliam, C. B.; Haas, A.; Haber, C.; Hadavand, H. K.; Haddad, N.; Haefner, P.; Hageböck, S.; Hajduk, Z.; Hakobyan, H.; Haleem, M.; Haley, J.; Hall, D.; Halladjian, G.; Hallewell, G. D.; Hamacher, K.; Hamal, P.; Hamano, K.; Hamer, M.; Hamilton, A.; Hamity, G. N.; Hamnett, P. G.; Han, L.; Hanagaki, K.; Hanawa, K.; Hance, M.; Hanke, P.; Hanna, R.; Hansen, J. B.; Hansen, J. D.; Hansen, M. C.; Hansen, P. H.; Hara, K.; Hard, A. S.; Harenberg, T.; Hariri, F.; Harkusha, S.; Harrington, R. D.; Harrison, P. F.; Hartjes, F.; Hasegawa, M.; Hasegawa, S.; Hasegawa, Y.; Hasib, A.; Hassani, S.; Haug, S.; Hauser, R.; Hauswald, L.; Havranek, M.; Hawkes, C. M.; Hawkings, R. J.; Hawkins, A. D.; Hayashi, T.; Hayden, D.; Hays, C. P.; Hays, J. M.; Hayward, H. S.; Haywood, S. J.; Head, S. J.; Heck, T.; Hedberg, V.; Heelan, L.; Heim, S.; Heim, T.; Heinemann, B.; Heinrich, L.; Hejbal, J.; Helary, L.; Hellman, S.; Hellmich, D.; Helsens, C.; Henderson, J.; Henderson, R. C. W.; Heng, Y.; Hengler, C.; Henrichs, A.; Henriques Correia, A. M.; Henrot-Versille, S.; Herbert, G. H.; Hernández Jiménez, Y.; Herrberg-Schubert, R.; Herten, G.; Hertenberger, R.; Hervas, L.; Hesketh, G. G.; Hessey, N. P.; Hetherly, J. W.; Hickling, R.; Higón-Rodriguez, E.; Hill, E.; Hill, J. C.; Hiller, K. H.; Hillier, S. J.; Hinchliffe, I.; Hines, E.; Hinman, R. R.; Hirose, M.; Hirschbuehl, D.; Hobbs, J.; Hod, N.; Hodgkinson, M. C.; Hodgson, P.; Hoecker, A.; Hoeferkamp, M. R.; Hoenig, F.; Hohlfeld, M.; Hohn, D.; Holmes, T. R.; Homann, M.; Hong, T. M.; Hooft van Huysduynen, L.; Hopkins, W. H.; Horii, Y.; Horton, A. J.; Hostachy, J.-Y.; Hou, S.; Hoummada, A.; Howard, J.; Howarth, J.; Hrabovsky, M.; Hristova, I.; Hrivnac, J.; Hryn'ova, T.; Hrynevich, A.; Hsu, C.; Hsu, P. J.; Hsu, S.-C.; Hu, D.; Hu, Q.; Hu, X.; Huang, Y.; Hubacek, Z.; Hubaut, F.; Huegging, F.; Huffman, T. B.; Hughes, E. W.; Hughes, G.; Huhtinen, M.; Hülsing, T. A.; Huseynov, N.; Huston, J.; Huth, J.; Iacobucci, G.; Iakovidis, G.; Ibragimov, I.; Iconomidou-Fayard, L.; Ideal, E.; Idrissi, Z.; Iengo, P.; Igonkina, O.; Iizawa, T.; Ikegami, Y.; Ikematsu, K.; Ikeno, M.; Ilchenko, Y.; Iliadis, D.; Ilic, N.; Ince, T.; Introzzi, G.; Ioannou, P.; Iodice, M.; Iordanidou, K.; Ippolito, V.; Irles Quiles, A.; Isaksson, C.; Ishino, M.; Ishitsuka, M.; Ishmukhametov, R.; Issever, C.; Istin, S.; Iturbe Ponce, J. M.; Iuppa, R.; Ivarsson, J.; Iwanski, W.; Iwasaki, H.; Izen, J. M.; Izzo, V.; Jabbar, S.; Jackson, B.; Jackson, M.; Jackson, P.; Jaekel, M. R.; Jain, V.; Jakobs, K.; Jakobsen, S.; Jakoubek, T.; Jakubek, J.; Jamin, D. O.; Jana, D. K.; Jansen, E.; Jansky, R.; Janssen, J.; Janus, M.; Jarlskog, G.; Javadov, N.; Javůrek, T.; Jeanty, L.; Jejelava, J.; Jeng, G.-Y.; Jennens, D.; Jenni, P.; Jentzsch, J.; Jeske, C.; Jézéquel, S.; Ji, H.; Jia, J.; Jiang, Y.; Jiggins, S.; Jimenez Pena, J.; Jin, S.; Jinaru, A.; Jinnouchi, O.; Joergensen, M. D.; Johansson, P.; Johns, K. A.; Jon-And, K.; Jones, G.; Jones, R. W. L.; Jones, T. J.; Jongmanns, J.; Jorge, P. M.; Joshi, K. D.; Jovicevic, J.; Ju, X.; Jung, C. A.; Jussel, P.; Juste Rozas, A.; Kaci, M.; Kaczmarska, A.; Kado, M.; Kagan, H.; Kagan, M.; Kahn, S. J.; Kajomovitz, E.; Kalderon, C. W.; Kama, S.; Kamenshchikov, A.; Kanaya, N.; Kaneti, S.; Kantserov, V. A.; Kanzaki, J.; Kaplan, B.; Kaplan, L. S.; Kapliy, A.; Kar, D.; Karakostas, K.; Karamaoun, A.; Karastathis, N.; Kareem, M. J.; Karnevskiy, M.; Karpov, S. N.; Karpova, Z. M.; Karthik, K.; Kartvelishvili, V.; Karyukhin, A. N.; Kashif, L.; Kass, R. D.; Kastanas, A.; Kataoka, Y.; Katre, A.; Katzy, J.; Kawagoe, K.; Kawamoto, T.; Kawamura, G.; Kazama, S.; Kazanin, V. F.; Kazarinov, M. Y.; Keeler, R.; Kehoe, R.; Keller, J. S.; Kempster, J. J.; Keoshkerian, H.; Kepka, O.; Kerševan, B. P.; Kersten, S.; Keyes, R. A.; Khalil-zada, F.; Khandanyan, H.; Khanov, A.; Kharlamov, A. G.; Khoo, T. J.; Khovanskiy, V.; Khramov, E.; Khubua, J.; Kim, H. Y.; Kim, H.; Kim, S. H.; Kim, Y.; Kimura, N.; Kind, O. M.; King, B. T.; King, M.; King, S. B.; Kirk, J.; Kiryunin, A. E.; Kishimoto, T.; Kisielewska, D.; Kiss, F.; Kiuchi, K.; Kivernyk, O.; Kladiva, E.; Klein, M. H.; Klein, M.; Klein, U.; Kleinknecht, K.; Klimek, P.; Klimentov, A.; Klingenberg, R.; Klinger, J. A.; Klioutchnikova, T.; Kluge, E.-E.; Kluit, P.; Kluth, S.; Knapik, J.; Kneringer, E.; Knoops, E. B. F. G.; Knue, A.; Kobayashi, A.; Kobayashi, D.; Kobayashi, T.; Kobel, M.; Kocian, M.; Kodys, P.; Koffas, T.; Koffeman, E.; Kogan, L. A.; Kohlmann, S.; Kohout, Z.; Kohriki, T.; Koi, T.; Kolanoski, H.; Koletsou, I.; Komar, A. A.; Komori, Y.; Kondo, T.; Kondrashova, N.; Köneke, K.; König, A. C.; Kono, T.; Konoplich, R.; Konstantinidis, N.; Kopeliansky, R.; Koperny, S.; Köpke, L.; Kopp, A. K.; Korcyl, K.; Kordas, K.; Korn, A.; Korol, A. A.; Korolkov, I.; Korolkova, E. V.; Kortner, O.; Kortner, S.; Kosek, T.; Kostyukhin, V. V.; Kotov, V. M.; Kotwal, A.; Kourkoumeli-Charalampidi, A.; Kourkoumelis, C.; Kouskoura, V.; Koutsman, A.; Kowalewski, R.; Kowalski, T. Z.; Kozanecki, W.; Kozhin, A. S.; Kramarenko, V. A.; Kramberger, G.; Krasnopevtsev, D.; Krasny, M. W.; Krasznahorkay, A.; Kraus, J. K.; Kravchenko, A.; Kreiss, S.; Kretz, M.; Kretzschmar, J.; Kreutzfeldt, K.; Krieger, P.; Krizka, K.; Kroeninger, K.; Kroha, H.; Kroll, J.; Kroseberg, J.; Krstic, J.; Kruchonak, U.; Krüger, H.; Krumnack, N.; Krumshteyn, Z. V.; Kruse, A.; Kruse, M. C.; Kruskal, M.; Kubota, T.; Kucuk, H.; Kuday, S.; Kuehn, S.; Kugel, A.; Kuger, F.; Kuhl, A.; Kuhl, T.; Kukhtin, V.; Kulchitsky, Y.; Kuleshov, S.; Kuna, M.; Kunigo, T.; Kupco, A.; Kurashige, H.; Kurochkin, Y. A.; Kus, V.; Kuwertz, E. S.; Kuze, M.; Kvita, J.; Kwan, T.; Kyriazopoulos, D.; La Rosa, A.; La Rosa Navarro, J. L.; La Rotonda, L.; Lacasta, C.; Lacava, F.; Lacey, J.; Lacker, H.; Lacour, D.; Lacuesta, V. R.; Ladygin, E.; Lafaye, R.; Laforge, B.; Lagouri, T.; Lai, S.; Lambourne, L.; Lammers, S.; Lampen, C. L.; Lampl, W.; Lançon, E.; Landgraf, U.; Landon, M. P. J.; Lang, V. S.; Lange, J. C.; Lankford, A. J.; Lanni, F.; Lantzsch, K.; Lanza, A.; Laplace, S.; Lapoire, C.; Laporte, J. F.; Lari, T.; Lasagni Manghi, F.; Lassnig, M.; Laurelli, P.; Lavrijsen, W.; Law, A. T.; Laycock, P.; Lazovich, T.; Le Dortz, O.; Le Guirriec, E.; Le Menedeu, E.; LeBlanc, M.; LeCompte, T.; Ledroit-Guillon, F.; Lee, C. A.; Lee, S. C.; Lee, L.; Lefebvre, G.; Lefebvre, M.; Legger, F.; Leggett, C.; Lehan, A.; Lehmann Miotto, G.; Lei, X.; Leight, W. A.; Leisos, A.; Leister, A. G.; Leite, M. A. L.; Leitner, R.; Lellouch, D.; Lemmer, B.; Leney, K. J. C.; Lenz, T.; Lenzi, B.; Leone, R.; Leone, S.; Leonidopoulos, C.; Leontsinis, S.; Leroy, C.; Lester, C. G.; Levchenko, M.; Levêque, J.; Levin, D.; Levinson, L. J.; Levy, M.; Lewis, A.; Leyko, A. M.; Leyton, M.; Li, B.; Li, H.; Li, H. L.; Li, L.; Li, L.; Li, S.; Li, Y.; Liang, Z.; Liao, H.; Liberti, B.; Liblong, A.; Lichard, P.; Lie, K.; Liebal, J.; Liebig, W.; Limbach, C.; Limosani, A.; Lin, S. C.; Lin, T. H.; Linde, F.; Lindquist, B. E.; Linnemann, J. T.; Lipeles, E.; Lipniacka, A.; Lisovyi, M.; Liss, T. M.; Lissauer, D.; Lister, A.; Litke, A. M.; Liu, B.; Liu, D.; Liu, H.; Liu, J.; Liu, J. B.; Liu, K.; Liu, L.; Liu, M.; Liu, M.; Liu, Y.; Livan, M.; Lleres, A.; Llorente Merino, J.; Lloyd, S. L.; Lo Sterzo, F.; Lobodzinska, E.; Loch, P.; Lockman, W. S.; Loebinger, F. K.; Loevschall-Jensen, A. E.; Loginov, A.; Lohse, T.; Lohwasser, K.; Lokajicek, M.; Long, B. A.; Long, J. D.; Long, R. E.; Looper, K. A.; Lopes, L.; Lopez Mateos, D.; Lopez Paredes, B.; Lopez Paz, I.; Lorenz, J.; Lorenzo Martinez, N.; Losada, M.; Loscutoff, P.; Lösel, P. J.; Lou, X.; Lounis, A.; Love, J.; Love, P. A.; Lu, N.; Lubatti, H. J.; Luci, C.; Lucotte, A.; Luehring, F.; Lukas, W.; Luminari, L.; Lundberg, O.; Lund-Jensen, B.; Lynn, D.; Lysak, R.; Lytken, E.; Ma, H.; Ma, L. L.; Maccarrone, G.; Macchiolo, A.; Macdonald, C. M.; Machado Miguens, J.; Macina, D.; Madaffari, D.; Madar, R.; Maddocks, H. J.; Mader, W. F.; Madsen, A.; Maeland, S.; Maeno, T.; Maevskiy, A.; Magradze, E.; Mahboubi, K.; Mahlstedt, J.; Maiani, C.; Maidantchik, C.; Maier, A. A.; Maier, T.; Maio, A.; Majewski, S.; Makida, Y.; Makovec, N.; Malaescu, B.; Malecki, Pa.; Maleev, V. P.; Malek, F.; Mallik, U.; Malon, D.; Malone, C.; Maltezos, S.; Malyshev, V. M.; Malyukov, S.; Mamuzic, J.; Mancini, G.; Mandelli, B.; Mandelli, L.; Mandić, I.; Mandrysch, R.; Maneira, J.; Manfredini, A.; Manhaes de Andrade Filho, L.; Manjarres Ramos, J.; Mann, A.; Manning, P. M.; Manousakis-Katsikakis, A.; Mansoulie, B.; Mantifel, R.; Mantoani, M.; Mapelli, L.; March, L.; Marchiori, G.; Marcisovsky, M.; Marino, C. P.; Marjanovic, M.; Marley, D. E.; Marroquim, F.; Marsden, S. P.; Marshall, Z.; Marti, L. F.; Marti-Garcia, S.; Martin, B.; Martin, T. A.; Martin, V. J.; Martin dit Latour, B.; Martinez, M.; Martin-Haugh, S.; Martoiu, V. S.; Martyniuk, A. C.; Marx, M.; Marzano, F.; Marzin, A.; Masetti, L.; Mashimo, T.; Mashinistov, R.; Masik, J.; Maslennikov, A. L.; Massa, I.; Massa, L.; Massol, N.; Mastrandrea, P.; Mastroberardino, A.; Masubuchi, T.; Mättig, P.; Mattmann, J.; Maurer, J.; Maxfield, S. J.; Maximov, D. A.; Mazini, R.; Mazza, S. M.; Mazzaferro, L.; Mc Goldrick, G.; Mc Kee, S. P.; McCarn, A.; McCarthy, R. L.; McCarthy, T. G.; McCubbin, N. A.; McFarlane, K. W.; Mcfayden, J. A.; Mchedlidze, G.; McMahon, S. J.; McPherson, R. A.; Medinnis, M.; Meehan, S.; Mehlhase, S.; Mehta, A.; Meier, K.; Meineck, C.; Meirose, B.; Mellado Garcia, B. R.; Meloni, F.; Mengarelli, A.; Menke, S.; Meoni, E.; Mercurio, K. M.; Mergelmeyer, S.; Mermod, P.; Merola, L.; Meroni, C.; Merritt, F. S.; Messina, A.; Metcalfe, J.; Mete, A. S.; Meyer, C.; Meyer, C.; Meyer, J.-P.; Meyer, J.; Middleton, R. P.; Miglioranzi, S.; Mijović, L.; Mikenberg, G.; Mikestikova, M.; Mikuž, M.; Milesi, M.; Milic, A.; Miller, D. W.; Mills, C.; Milov, A.; Milstead, D. A.; Minaenko, A. A.; Minami, Y.; Minashvili, I. A.; Mincer, A. I.; Mindur, B.; Mineev, M.; Ming, Y.; Mir, L. M.; Mitani, T.; Mitrevski, J.; Mitsou, V. A.; Miucci, A.; Miyagawa, P. S.; Mjörnmark, J. U.; Moa, T.; Mochizuki, K.; Mohapatra, S.; Mohr, W.; Molander, S.; Moles-Valls, R.; Mönig, K.; Monini, C.; Monk, J.; Monnier, E.; Montejo Berlingen, J.; Monticelli, F.; Monzani, S.; Moore, R. W.; Morange, N.; Moreno, D.; Moreno Llácer, M.; Morettini, P.; Morgenstern, M.; Morii, M.; Morinaga, M.; Morisbak, V.; Moritz, S.; Morley, A. K.; Mornacchi, G.; Morris, J. D.; Mortensen, S. S.; Morton, A.; Morvaj, L.; Mosidze, M.; Moss, J.; Motohashi, K.; Mount, R.; Mountricha, E.; Mouraviev, S. V.; Moyse, E. J. W.; Muanza, S.; Mudd, R. D.; Mueller, F.; Mueller, J.; Mueller, R. S. P.; Mueller, T.; Muenstermann, D.; Mullen, P.; Mullier, G. A.; Murillo Quijada, J. A.; Murray, W. J.; Musheghyan, H.; Musto, E.; Myagkov, A. G.; Myska, M.; Nackenhorst, O.; Nadal, J.; Nagai, K.; Nagai, R.; Nagai, Y.; Nagano, K.; Nagarkar, A.; Nagasaka, Y.; Nagata, K.; Nagel, M.; Nagy, E.; Nairz, A. M.; Nakahama, Y.; Nakamura, K.; Nakamura, T.; Nakano, I.; Namasivayam, H.; Naranjo Garcia, R. F.; Narayan, R.; Naumann, T.; Navarro, G.; Nayyar, R.; Neal, H. A.; Nechaeva, P. Yu.; Neep, T. J.; Nef, P. D.; Negri, A.; Negrini, M.; Nektarijevic, S.; Nellist, C.; Nelson, A.; Nemecek, S.; Nemethy, P.; Nepomuceno, A. A.; Nessi, M.; Neubauer, M. S.; Neumann, M.; Neves, R. M.; Nevski, P.; Newman, P. R.; Nguyen, D. H.; Nickerson, R. B.; Nicolaidou, R.; Nicquevert, B.; Nielsen, J.; Nikiforou, N.; Nikiforov, A.; Nikolaenko, V.; Nikolic-Audit, I.; Nikolopoulos, K.; Nilsen, J. K.; Nilsson, P.; Ninomiya, Y.; Nisati, A.; Nisius, R.; Nobe, T.; Nomachi, M.; Nomidis, I.; Nooney, T.; Norberg, S.; Nordberg, M.; Novgorodova, O.; Nowak, S.; Nozaki, M.; Nozka, L.; Ntekas, K.; Nunes Hanninger, G.; Nunnemann, T.; Nurse, E.; Nuti, F.; O'Brien, B. J.; O'grady, F.; O'Neil, D. C.; O'Shea, V.; Oakham, F. G.; Oberlack, H.; Obermann, T.; Ocariz, J.; Ochi, A.; Ochoa, I.; Ochoa-Ricoux, J. P.; Oda, S.; Odaka, S.; Ogren, H.; Oh, A.; Oh, S. H.; Ohm, C. C.; Ohman, H.; Oide, H.; Okamura, W.; Okawa, H.; Okumura, Y.; Okuyama, T.; Olariu, A.; Olivares Pino, S. A.; Oliveira Damazio, D.; Oliver Garcia, E.; Olszewski, A.; Olszowska, J.; Onofre, A.; Onyisi, P. U. E.; Oram, C. J.; Oreglia, M. J.; Oren, Y.; Orestano, D.; Orlando, N.; Oropeza Barrera, C.; Orr, R. S.; Osculati, B.; Ospanov, R.; Otero y Garzon, G.; Otono, H.; Ouchrif, M.; Ouellette, E. A.; Ould-Saada, F.; Ouraou, A.; Oussoren, K. P.; Ouyang, Q.; Ovcharova, A.; Owen, M.; Owen, R. E.; Ozcan, V. E.; Ozturk, N.; Pachal, K.; Pacheco Pages, A.; Padilla Aranda, C.; Pagáčová, M.; Pagan Griso, S.; Paganis, E.; Paige, F.; Pais, P.; Pajchel, K.; Palacino, G.; Palestini, S.; Palka, M.; Pallin, D.; Palma, A.; Pan, Y. B.; Panagiotopoulou, E.; Pandini, C. E.; Panduro Vazquez, J. G.; Pani, P.; Panitkin, S.; Pantea, D.; Paolozzi, L.; Papadopoulou, Th. D.; Papageorgiou, K.; Paramonov, A.; Paredes Hernandez, D.; Parker, M. A.; Parker, K. A.; Parodi, F.; Parsons, J. A.; Parzefall, U.; Pasqualucci, E.; Passaggio, S.; Pastore, F.; Pastore, Fr.; Pásztor, G.; Pataraia, S.; Patel, N. D.; Pater, J. R.; Pauly, T.; Pearce, J.; Pearson, B.; Pedersen, L. E.; Pedersen, M.; Pedraza Lopez, S.; Pedro, R.; Peleganchuk, S. V.; Pelikan, D.; Penc, O.; Peng, C.; Peng, H.; Penning, B.; Penwell, J.; Perepelitsa, D. V.; Perez Codina, E.; Pérez García-Estañ, M. T.; Perini, L.; Pernegger, H.; Perrella, S.; Peschke, R.; Peshekhonov, V. D.; Peters, K.; Peters, R. F. Y.; Petersen, B. A.; Petersen, T. C.; Petit, E.; Petridis, A.; Petridou, C.; Petrolo, E.; Petrucci, F.; Pettersson, N. E.; Pezoa, R.; Phillips, P. W.; Piacquadio, G.; Pianori, E.; Picazio, A.; Piccaro, E.; Piccinini, M.; Pickering, M. A.; Piegaia, R.; Pignotti, D. T.; Pilcher, J. E.; Pilkington, A. D.; Pina, J.; Pinamonti, M.; Pinfold, J. L.; Pingel, A.; Pinto, B.; Pires, S.; Pirumov, H.; Pitt, M.; Pizio, C.; Plazak, L.; Pleier, M.-A.; Pleskot, V.; Plotnikova, E.; Plucinski, P.; Pluth, D.; Poettgen, R.; Poggioli, L.; Pohl, D.; Polesello, G.; Poley, A.; Policicchio, A.; Polifka, R.; Polini, A.; Pollard, C. S.; Polychronakos, V.; Pommès, K.; Pontecorvo, L.; Pope, B. G.; Popeneciu, G. A.; Popovic, D. S.; Poppleton, A.; Pospisil, S.; Potamianos, K.; Potrap, I. N.; Potter, C. J.; Potter, C. T.; Poulard, G.; Poveda, J.; Pozdnyakov, V.; Pralavorio, P.; Pranko, A.; Prasad, S.; Prell, S.; Price, D.; Price, L. E.; Primavera, M.; Prince, S.; Proissl, M.; Prokofiev, K.; Prokoshin, F.; Protopapadaki, E.; Protopopescu, S.; Proudfoot, J.; Przybycien, M.; Ptacek, E.; Puddu, D.; Pueschel, E.; Puldon, D.; Purohit, M.; Puzo, P.; Qian, J.; Qin, G.; Qin, Y.; Quadt, A.; Quarrie, D. R.; Quayle, W. B.; Queitsch-Maitland, M.; Quilty, D.; Raddum, S.; Radeka, V.; Radescu, V.; Radhakrishnan, S. K.; Radloff, P.; Rados, P.; Ragusa, F.; Rahal, G.; Rajagopalan, S.; Rammensee, M.; Rangel-Smith, C.; Rauscher, F.; Rave, S.; Ravenscroft, T.; Raymond, M.; Read, A. L.; Readioff, N. P.; Rebuzzi, D. M.; Redelbach, A.; Redlinger, G.; Reece, R.; Reeves, K.; Rehnisch, L.; Reisin, H.; Relich, M.; Rembser, C.; Ren, H.; Renaud, A.; Rescigno, M.; Resconi, S.; Rezanova, O. L.; Reznicek, P.; Rezvani, R.; Richter, R.; Richter, S.; Richter-Was, E.; Ricken, O.; Ridel, M.; Rieck, P.; Riegel, C. J.; Rieger, J.; Rijssenbeek, M.; Rimoldi, A.; Rinaldi, L.; Ristić, B.; Ritsch, E.; Riu, I.; Rizatdinova, F.; Rizvi, E.; Robertson, S. H.; Robichaud-Veronneau, A.; Robinson, D.; Robinson, J. E. M.; Robson, A.; Roda, C.; Roe, S.; Røhne, O.; Rolli, S.; Romaniouk, A.; Romano, M.; Romano Saez, S. M.; Romero Adam, E.; Rompotis, N.; Ronzani, M.; Roos, L.; Ros, E.; Rosati, S.; Rosbach, K.; Rose, P.; Rosendahl, P. L.; Rosenthal, O.; Rossetti, V.; Rossi, E.; Rossi, L. P.; Rosten, R.; Rotaru, M.; Roth, I.; Rothberg, J.; Rousseau, D.; Royon, C. R.; Rozanov, A.; Rozen, Y.; Ruan, X.; Rubbo, F.; Rubinskiy, I.; Rud, V. I.; Rudolph, C.; Rudolph, M. S.; Rühr, F.; Ruiz-Martinez, A.; Rurikova, Z.; Rusakovich, N. A.; Ruschke, A.; Russell, H. L.; Rutherfoord, J. P.; Ruthmann, N.; Ryabov, Y. F.; Rybar, M.; Rybkin, G.; Ryder, N. C.; Saavedra, A. F.; Sabato, G.; Sacerdoti, S.; Saddique, A.; Sadrozinski, H. F.-W.; Sadykov, R.; Safai Tehrani, F.; Saimpert, M.; Sakamoto, H.; Sakurai, Y.; Salamanna, G.; Salamon, A.; Saleem, M.; Salek, D.; Sales De Bruin, P. H.; Salihagic, D.; Salnikov, A.; Salt, J.; Salvatore, D.; Salvatore, F.; Salvucci, A.; Salzburger, A.; Sampsonidis, D.; Sanchez, A.; Sánchez, J.; Sanchez Martinez, V.; Sandaker, H.; Sandbach, R. L.; Sander, H. G.; Sanders, M. P.; Sandhoff, M.; Sandoval, C.; Sandstroem, R.; Sankey, D. P. C.; Sannino, M.; Sansoni, A.; Santoni, C.; Santonico, R.; Santos, H.; Santoyo Castillo, I.; Sapp, K.; Sapronov, A.; Saraiva, J. G.; Sarrazin, B.; Sasaki, O.; Sasaki, Y.; Sato, K.; Sauvage, G.; Sauvan, E.; Savage, G.; Savard, P.; Sawyer, C.; Sawyer, L.; Saxon, J.; Sbarra, C.; Sbrizzi, A.; Scanlon, T.; Scannicchio, D. A.; Scarcella, M.; Scarfone, V.; Schaarschmidt, J.; Schacht, P.; Schaefer, D.; Schaefer, R.; Schaeffer, J.; Schaepe, S.; Schaetzel, S.; Schäfer, U.; Schaffer, A. C.; Schaile, D.; Schamberger, R. D.; Scharf, V.; Schegelsky, V. A.; Scheirich, D.; Schernau, M.; Schiavi, C.; Schillo, C.; Schioppa, M.; Schlenker, S.; Schmidt, E.; Schmieden, K.; Schmitt, C.; Schmitt, S.; Schmitt, S.; Schneider, B.; Schnellbach, Y. J.; Schnoor, U.; Schoeffel, L.; Schoening, A.; Schoenrock, B. D.; Schopf, E.; Schorlemmer, A. L. S.; Schott, M.; Schouten, D.; Schovancova, J.; Schramm, S.; Schreyer, M.; Schroeder, C.; Schuh, N.; Schultens, M. J.; Schultz-Coulon, H.-C.; Schulz, H.; Schumacher, M.; Schumm, B. A.; Schune, Ph.; Schwanenberger, C.; Schwartzman, A.; Schwarz, T. A.; Schwegler, Ph.; Schweiger, H.; Schwemling, Ph.; Schwienhorst, R.; Schwindling, J.; Schwindt, T.; Sciacca, F. G.; Scifo, E.; Sciolla, G.; Scuri, F.; Scutti, F.; Searcy, J.; Sedov, G.; Sedykh, E.; Seema, P.; Seidel, S. C.; Seiden, A.; Seifert, F.; Seixas, J. M.; Sekhniaidze, G.; Sekhon, K.; Sekula, S. J.; Seliverstov, D. M.; Semprini-Cesari, N.; Serfon, C.; Serin, L.; Serkin, L.; Serre, T.; Sessa, M.; Seuster, R.; Severini, H.; Sfiligoj, T.; Sforza, F.; Sfyrla, A.; Shabalina, E.; Shamim, M.; Shan, L. Y.; Shang, R.; Shank, J. T.; Shapiro, M.; Shatalov, P. B.; Shaw, K.; Shaw, S. M.; Shcherbakova, A.; Shehu, C. Y.; Sherwood, P.; Shi, L.; Shimizu, S.; Shimmin, C. O.; Shimojima, M.; Shiyakova, M.; Shmeleva, A.; Shoaleh Saadi, D.; Shochet, M. J.; Shojaii, S.; Shrestha, S.; Shulga, E.; Shupe, M. A.; Shushkevich, S.; Sicho, P.; Sidebo, P. E.; Sidiropoulou, O.; Sidorov, D.; Sidoti, A.; Siegert, F.; Sijacki, Dj.; Silva, J.; Silver, Y.; Silverstein, S. B.; Simak, V.; Simard, O.; Simic, Lj.; Simion, S.; Simioni, E.; Simmons, B.; Simon, D.; Simoniello, R.; Sinervo, P.; Sinev, N. B.; Sioli, M.; Siragusa, G.; Sisakyan, A. N.; Sivoklokov, S. Yu.; Sjölin, J.; Sjursen, T. B.; Skinner, M. B.; Skottowe, H. P.; Skubic, P.; Slater, M.; Slavicek, T.; Slawinska, M.; Sliwa, K.; Smakhtin, V.; Smart, B. H.; Smestad, L.; Smirnov, S. Yu.; Smirnov, Y.; Smirnova, L. N.; Smirnova, O.; Smith, M. N. K.; Smith, R. W.; Smizanska, M.; Smolek, K.; Snesarev, A. A.; Snidero, G.; Snyder, S.; Sobie, R.; Socher, F.; Soffer, A.; Soh, D. A.; Solans, C. A.; Solar, M.; Solc, J.; Soldatov, E. Yu.; Soldevila, U.; Solodkov, A. A.; Soloshenko, A.; Solovyanov, O. V.; Solovyev, V.; Sommer, P.; Song, H. Y.; Soni, N.; Sood, A.; Sopczak, A.; Sopko, B.; Sopko, V.; Sorin, V.; Sosa, D.; Sosebee, M.; Sotiropoulou, C. L.; Soualah, R.; Soukharev, A. M.; South, D.; Sowden, B. C.; Spagnolo, S.; Spalla, M.; Spanò, F.; Spearman, W. R.; Sperlich, D.; Spettel, F.; Spighi, R.; Spigo, G.; Spiller, L. A.; Spousta, M.; Spreitzer, T.; St. Denis, R. D.; Staerz, S.; Stahlman, J.; Stamen, R.; Stamm, S.; Stanecka, E.; Stanescu, C.; Stanescu-Bellu, M.; Stanitzki, M. M.; Stapnes, S.; Starchenko, E. A.; Stark, J.; Staroba, P.; Starovoitov, P.; Staszewski, R.; Stavina, P.; Steinberg, P.; Stelzer, B.; Stelzer, H. J.; Stelzer-Chilton, O.; Stenzel, H.; Stewart, G. A.; Stillings, J. A.; Stockton, M. C.; Stoebe, M.; Stoicea, G.; Stolte, P.; Stonjek, S.; Stradling, A. R.; Straessner, A.; Stramaglia, M. E.; Strandberg, J.; Strandberg, S.; Strandlie, A.; Strauss, E.; Strauss, M.; Strizenec, P.; Ströhmer, R.; Strom, D. M.; Stroynowski, R.; Strubig, A.; Stucci, S. A.; Stugu, B.; Styles, N. A.; Su, D.; Su, J.; Subramaniam, R.; Succurro, A.; Sugaya, Y.; Suhr, C.; Suk, M.; Sulin, V. V.; Sultansoy, S.; Sumida, T.; Sun, S.; Sun, X.; Sundermann, J. E.; Suruliz, K.; Susinno, G.; Sutton, M. R.; Suzuki, S.; Svatos, M.; Swedish, S.; Swiatlowski, M.; Sykora, I.; Sykora, T.; Ta, D.; Taccini, C.; Tackmann, K.; Taenzer, J.; Taffard, A.; Tafirout, R.; Taiblum, N.; Takai, H.; Takashima, R.; Takeda, H.; Takeshita, T.; Takubo, Y.; Talby, M.; Talyshev, A. A.; Tam, J. Y. C.; Tan, K. G.; Tanaka, J.; Tanaka, R.; Tanaka, S.; Tannenwald, B. B.; Tannoury, N.; Tapprogge, S.; Tarem, S.; Tarrade, F.; Tartarelli, G. F.; Tas, P.; Tasevsky, M.; Tashiro, T.; Tassi, E.; Tavares Delgado, A.; Tayalati, Y.; Taylor, F. E.; Taylor, G. N.; Taylor, W.; Teischinger, F. A.; Teixeira Dias Castanheira, M.; Teixeira-Dias, P.; Temming, K. K.; Ten Kate, H.; Teng, P. K.; Teoh, J. J.; Tepel, F.; Terada, S.; Terashi, K.; Terron, J.; Terzo, S.; Testa, M.; Teuscher, R. J.; Theveneaux-Pelzer, T.; Thomas, J. P.; Thomas-Wilsker, J.; Thompson, E. N.; Thompson, P. D.; Thompson, R. J.; Thompson, A. S.; Thomsen, L. A.; Thomson, E.; Thomson, M.; Thun, R. P.; Tibbetts, M. J.; Ticse Torres, R. E.; Tikhomirov, V. O.; Tikhonov, Yu. A.; Timoshenko, S.; Tiouchichine, E.; Tipton, P.; Tisserant, S.; Todome, K.; Todorov, T.; Todorova-Nova, S.; Tojo, J.; Tokár, S.; Tokushuku, K.; Tollefson, K.; Tolley, E.; Tomlinson, L.; Tomoto, M.; Tompkins, L.; Toms, K.; Torrence, E.; Torres, H.; Torró Pastor, E.; Toth, J.; Touchard, F.; Tovey, D. R.; Trefzger, T.; Tremblet, L.; Tricoli, A.; Trigger, I. M.; Trincaz-Duvoid, S.; Tripiana, M. F.; Trischuk, W.; Trocmé, B.; Troncon, C.; Trottier-McDonald, M.; Trovatelli, M.; True, P.; Truong, L.; Trzebinski, M.; Trzupek, A.; Tsarouchas, C.; Tseng, J. C.-L.; Tsiareshka, P. V.; Tsionou, D.; Tsipolitis, G.; Tsirintanis, N.; Tsiskaridze, S.; Tsiskaridze, V.; Tskhadadze, E. G.; Tsukerman, I. I.; Tsulaia, V.; Tsuno, S.; Tsybychev, D.; Tudorache, A.; Tudorache, V.; Tuna, A. N.; Tupputi, S. A.; Turchikhin, S.; Turecek, D.; Turra, R.; Turvey, A. J.; Tuts, P. M.; Tykhonov, A.; Tylmad, M.; Tyndel, M.; Ueda, I.; Ueno, R.; Ughetto, M.; Ugland, M.; Uhlenbrock, M.; Ukegawa, F.; Unal, G.; Undrus, A.; Unel, G.; Ungaro, F. C.; Unno, Y.; Unverdorben, C.; Urban, J.; Urquijo, P.; Urrejola, P.; Usai, G.; Usanova, A.; Vacavant, L.; Vacek, V.; Vachon, B.; Valderanis, C.; Valencic, N.; Valentinetti, S.; Valero, A.; Valery, L.; Valkar, S.; Valladolid Gallego, E.; Vallecorsa, S.; Valls Ferrer, J. A.; Van Den Wollenberg, W.; Van Der Deijl, P. C.; van der Geer, R.; van der Graaf, H.; Van Der Leeuw, R.; van Eldik, N.; van Gemmeren, P.; Van Nieuwkoop, J.; van Vulpen, I.; van Woerden, M. C.; Vanadia, M.; Vandelli, W.; Vanguri, R.; Vaniachine, A.; Vannucci, F.; Vardanyan, G.; Vari, R.; Varnes, E. W.; Varol, T.; Varouchas, D.; Vartapetian, A.; Varvell, K. E.; Vazeille, F.; Vazquez Schroeder, T.; Veatch, J.; Veloce, L. M.; Veloso, F.; Velz, T.; Veneziano, S.; Ventura, A.; Ventura, D.; Venturi, M.; Venturi, N.; Venturini, A.; Vercesi, V.; Verducci, M.; Verkerke, W.; Vermeulen, J. C.; Vest, A.; Vetterli, M. C.; Viazlo, O.; Vichou, I.; Vickey, T.; Vickey Boeriu, O. E.; Viehhauser, G. H. A.; Viel, S.; Vigne, R.; Villa, M.; Villaplana Perez, M.; Vilucchi, E.; Vincter, M. G.; Vinogradov, V. B.; Vivarelli, I.; Vives Vaque, F.; Vlachos, S.; Vladoiu, D.; Vlasak, M.; Vogel, M.; Vokac, P.; Volpi, G.; Volpi, M.; von der Schmitt, H.; von Radziewski, H.; von Toerne, E.; Vorobel, V.; Vorobev, K.; Vos, M.; Voss, R.; Vossebeld, J. H.; Vranjes, N.; Vranjes Milosavljevic, M.; Vrba, V.; Vreeswijk, M.; Vuillermet, R.; Vukotic, I.; Vykydal, Z.; Wagner, P.; Wagner, W.; Wahlberg, H.; Wahrmund, S.; Wakabayashi, J.; Walder, J.; Walker, R.; Walkowiak, W.; Wang, C.; Wang, F.; Wang, H.; Wang, H.; Wang, J.; Wang, J.; Wang, K.; Wang, R.; Wang, S. M.; Wang, T.; Wang, T.; Wang, X.; Wanotayaroj, C.; Warburton, A.; Ward, C. P.; Wardrope, D. R.; Warsinsky, M.; Washbrook, A.; Wasicki, C.; Watkins, P. M.; Watson, A. T.; Watson, I. J.; Watson, M. F.; Watts, G.; Watts, S.; Waugh, B. M.; Webb, S.; Weber, M. S.; Weber, S. W.; Webster, J. S.; Weidberg, A. R.; Weinert, B.; Weingarten, J.; Weiser, C.; Weits, H.; Wells, P. S.; Wenaus, T.; Wengler, T.; Wenig, S.; Wermes, N.; Werner, M.; Werner, P.; Wessels, M.; Wetter, J.; Whalen, K.; Wharton, A. M.; White, A.; White, M. J.; White, R.; White, S.; Whiteson, D.; Wickens, F. J.; Wiedenmann, W.; Wielers, M.; Wienemann, P.; Wiglesworth, C.; Wiik-Fuchs, L. A. M.; Wildauer, A.; Wilkens, H. G.; Williams, H. H.; Williams, S.; Willis, C.; Willocq, S.; Wilson, A.; Wilson, J. A.; Wingerter-Seez, I.; Winklmeier, F.; Winter, B. T.; Wittgen, M.; Wittkowski, J.; Wollstadt, S. J.; Wolter, M. W.; Wolters, H.; Wosiek, B. K.; Wotschack, J.; Woudstra, M. J.; Wozniak, K. W.; Wu, M.; Wu, M.; Wu, S. L.; Wu, X.; Wu, Y.; Wyatt, T. R.; Wynne, B. M.; Xella, S.; Xu, D.; Xu, L.; Yabsley, B.; Yacoob, S.; Yakabe, R.; Yamada, M.; Yamaguchi, Y.; Yamamoto, A.; Yamamoto, S.; Yamanaka, T.; Yamauchi, K.; Yamazaki, Y.; Yan, Z.; Yang, H.; Yang, H.; Yang, Y.; Yao, W.-M.; Yasu, Y.; Yatsenko, E.; Yau Wong, K. H.; Ye, J.; Ye, S.; Yeletskikh, I.; Yen, A. L.; Yildirim, E.; Yorita, K.; Yoshida, R.; Yoshihara, K.; Young, C.; Young, C. J. S.; Youssef, S.; Yu, D. R.; Yu, J.; Yu, J. M.; Yu, J.; Yuan, L.; Yurkewicz, A.; Yusuff, I.; Zabinski, B.; Zaidan, R.; Zaitsev, A. M.; Zalieckas, J.; Zaman, A.; Zambito, S.; Zanello, L.; Zanzi, D.; Zeitnitz, C.; Zeman, M.; Zemla, A.; Zengel, K.; Zenin, O.; Ženiš, T.; Zerwas, D.; Zhang, D.; Zhang, F.; Zhang, H.; Zhang, J.; Zhang, L.; Zhang, R.; Zhang, X.; Zhang, Z.; Zhao, X.; Zhao, Y.; Zhao, Z.; Zhemchugov, A.; Zhong, J.; Zhou, B.; Zhou, C.; Zhou, L.; Zhou, L.; Zhou, N.; Zhu, C. G.; Zhu, H.; Zhu, J.; Zhu, Y.; Zhuang, X.; Zhukov, K.; Zibell, A.; Zieminska, D.; Zimine, N. I.; Zimmermann, C.; Zimmermann, S.; Zinonos, Z.; Zinser, M.; Ziolkowski, M.; Živković, L.; Zobernig, G.; Zoccoli, A.; zur Nedden, M.; Zurzolo, G.; Zwalinski, L.

2015-10-01

Studies of the spin, parity and tensor couplings of the Higgs boson in the H → ZZ^{*} → 4 ℓ, H → WW^{*} → e ν μ ν and H → γ γ decay processes at the LHC are presented. The investigations are based on 25fb^{-1} of pp collision data collected by the ATLAS experiment at √{s}=7 TeV and √{s}=8 TeV. The Standard Model (SM) Higgs boson hypothesis, corresponding to the quantum numbers JP=0+, is tested against several alternative spin scenarios, including non-SM spin-0 and spin-2 models with universal and non-universal couplings to fermions and vector bosons. All tested alternative models are excluded in favour of the SM Higgs boson hypothesis at more than 99.9 % confidence level. Using the H → ZZ^{*} → 4 ℓ and H → WW^{*} → e ν μ ν decays, the tensor structure of the interaction between the spin-0 boson and the SM vector bosons is also investigated. The observed distributions of variables sensitive to the non-SM tensor couplings are compatible with the SM predictions and constraints on the non-SM couplings are derived.

Direct observation of isolated Damon-Eshbach and backward volume spin-wave packets in ferromagnetic microstripes

PubMed Central

Wessels, Philipp; Vogel, Andreas; Tödt, Jan-Niklas; Wieland, Marek; Meier, Guido; Drescher, Markus

2016-01-01

The analysis of isolated spin-wave packets is crucial for the understanding of magnetic transport phenomena and is particularly interesting for applications in spintronic and magnonic devices, where isolated spin-wave packets implement an information processing scheme with negligible residual heat loss. We have captured microscale magnetization dynamics of single spin-wave packets in metallic ferromagnets in space and time. Using an optically driven high-current picosecond pulse source in combination with time-resolved scanning Kerr microscopy probed by femtosecond laser pulses, we demonstrate phase-sensitive real-space observation of spin-wave packets in confined permalloy (Ni80Fe20) microstripes. Impulsive excitation permits extraction of the dynamical parameters, i.e. phase- and group velocities, frequencies and wave vectors. In addition to well-established Damon-Eshbach modes our study reveals waves with counterpropagating group- and phase-velocities. Such unusual spin-wave motion is expected for backward volume modes where the phase fronts approach the excitation volume rather than emerging out of it due to the negative slope of the dispersion relation. These modes are difficult to excite and observe directly but feature analogies to negative refractive index materials, thus enabling model studies of wave propagation inside metamaterials. PMID:26906113

Study of the spin and parity of the Higgs boson in diboson decays with the ATLAS detector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aad, G.

Studies of the spin, parity and tensor couplings of the Higgs boson in the H→ZZ*→4ℓ, H→WW*→eνμν and H→γγ decay processes at the LHC are presented. The investigations are based on 25fb –1 of pp collision data collected by the ATLAS experiment at √s=7 TeV and √s=8 TeV. The Standard Model (SM) Higgs boson hypothesis, corresponding to the quantum numbers JP=0 +, is tested against several alternative spin scenarios, including non-SM spin-0 and spin-2 models with universal and non-universal couplings to fermions and vector bosons. All tested alternative models are excluded in favour of the SM Higgs boson hypothesis at moremore » than 99.9 % confidence level. Using the H→ZZ*→4ℓ and H→WW*→eνμν decays, the tensor structure of the interaction between the spin-0 boson and the SM vector bosons is also investigated. Thus, the observed distributions of variables sensitive to the non SM tensor couplings are compatible with the SM predictions and constraints on the non SM couplings are derived.« less

Study of the spin and parity of the Higgs boson in diboson decays with the ATLAS detector

DOE PAGES

Aad, G.

2015-10-06

Studies of the spin, parity and tensor couplings of the Higgs boson in the H→ZZ*→4ℓ, H→WW*→eνμν and H→γγ decay processes at the LHC are presented. The investigations are based on 25fb –1 of pp collision data collected by the ATLAS experiment at √s=7 TeV and √s=8 TeV. The Standard Model (SM) Higgs boson hypothesis, corresponding to the quantum numbers JP=0 +, is tested against several alternative spin scenarios, including non-SM spin-0 and spin-2 models with universal and non-universal couplings to fermions and vector bosons. All tested alternative models are excluded in favour of the SM Higgs boson hypothesis at moremore » than 99.9 % confidence level. Using the H→ZZ*→4ℓ and H→WW*→eνμν decays, the tensor structure of the interaction between the spin-0 boson and the SM vector bosons is also investigated. Thus, the observed distributions of variables sensitive to the non SM tensor couplings are compatible with the SM predictions and constraints on the non SM couplings are derived.« less

Biomedical Nanomagnetics: A Spin Through Possibilities in Imaging, Diagnostics, and Therapy

PubMed Central

Krishnan, Kannan M.

2010-01-01

Biomedical nanomagnetics is a multidisciplinary area of research in science, engineering and medicine with broad applications in imaging, diagnostics and therapy. Recent developments offer exciting possibilities in personalized medicine provided a truly integrated approach, combining chemistry, materials science, physics, engineering, biology and medicine, is implemented. Emphasizing this perspective, here we address important issues for the rapid development of the field, i.e., magnetic behavior at the nanoscale with emphasis on the relaxation dynamics, synthesis and surface functionalization of nanoparticles and core-shell structures, biocompatibility and toxicity studies, biological constraints and opportunities, and in vivo and in vitro applications. Specifically, we discuss targeted drug delivery and triggered release, novel contrast agents for magnetic resonance imaging, cancer therapy using magnetic fluid hyperthermia, in vitro diagnostics and the emerging magnetic particle imaging technique, that is quantitative and sensitive enough to compete with established imaging methods. In addition, the physics of self-assembly, which is fundamental to both biology and the future development of nanoscience, is illustrated with magnetic nanoparticles. It is shown that various competing energies associated with self-assembly converge on the nanometer length scale and different assemblies can be tailored by varying particle size and size distribution. Throughout this paper, while we discuss our recent research in the broad context of the multidisciplinary literature, we hope to bridge the gap between related work in physics/chemistry/engineering and biology/medicine and, at the same time, present the essential concepts in the individual disciplines. This approach is essential as biomedical nanomagnetics moves into the next phase of innovative translational research with emphasis on development of quantitative in vivo imaging, targeted and triggered drug release, and image guided therapy including validation of delivery and therapy response. PMID:20930943

Synthesis and characterization of novel 2, 2'-bipyrimidine fluorescent derivative for protein binding

PubMed Central

2011-01-01

Background Fluorescent dyes with biocompatible functional group and good fluorescence behavior are used as biosensor for monitoring different biological processes as well as detection of protein assay. All reported fluorophore used as sensors are having high selectivity and sensitivity but till there is more demand to synthesized new fluorophore which have improved fluorescence properties and good biocompatibility. Results Novel 4, 4'-(1, 1'-(5-(2-methoxyphenoxy)-[2, 2'-bipyrimidine]-4, 6-diyl)bis(1H-pyrazol-3, 1-diyl)) dianiline fluorescent dye was synthesized by multistep synthesis from 2-phenylacetonitrile, 2-chloropyrimidine and 2-methoxyphenol. This dye has absorption at 379 nm with intense single emission at 497 nm having fairly good quantum yield (0.375) and Stokes shift. The intermediates and dye were characterized by FT-IR, 1H NMR, 13C NMR and Mass spectral analysis. The pyrazole bipyrimidine based fluorescent dye possessing two amino groups suitable for binding with protein is reported. Its utility as a biocompatible conjugate was explained by conjugation with bovine serum albumin. The method is based on direct fluorescence detection of fluorophore-labelled protein before and after conjugation. Purified fluorescent conjugate was subsequently analyzed by fluorimetry. The analysis showed that the tested conjugation reaction yielded fluorescent conjugates of the dye through carbodiimide chemistry. Conclusion In summery synthesized fluorophore pyrazole-bipyrimidine has very good interaction towards protein bovine serum albumin and it acts as good candidate for protein assay. PMID:22067202

Differences in bio-incompatibility among four biocompatible dialyzer membranes using in maintenance hemodialysis patients.

PubMed

Zhang, Dong-Liang; Liu, Jing; Cui, Wen-Ying; Ji, Dan-Ying; Zhang, Yue; Liu, Wen-Hu

2011-01-01

Following the introduction of modified cellulosic and then synthetic membrane dialyzers, it was realized that the dialyzer bio-incompatibility depends on the membrane composition. We designed a prospective, randomized, cohort study of 6 months to determine several parameters of biocompatibility in maintenance hemodialysis (MHD) patients treated with four different membrane dialyzers. There were 60 MHD patients enrolled in the study. In baseline, synthetic low-flux dialyzer, polysulfone (PS) membrane was used in all patients for at least 3 months. Then the patients were randomly divided into three groups according to different dialyzer membranes. Synthetic high-flux dialyzer group, polyethersulfone membrane, cellulose triacetate (CTA) high-flux membrane, and synthetic low-flux dialyzer, polymethylmethacrylate (PMMA) membrane were used in 6 months. A new dialyzer was used for each study treatment, and there was no dialyzer reuse. The biocompatibility markers and solutes removal markers were detected repeatedly at different time points. The blood levels of highly sensitive C reactive protein, interleukin (IL)-1β, and interleukin (IL)-13 showed no difference among different groups at al time points. However, the blood complement levels and white blood cell counts were significantly different among three groups. When the dialyzers changed from PS to PMMA membrane, C3a levels and white blood cell counts changed significantly (p < 0.05). Moreover, the changes of C5a levels were significantly different between group CTA and group PMMA in month 3 (p < 0.05). There were much more differences on bio-incompatibility among different dialyzer membranes.

In vitro bio-functionality of gallium nitride sensors for radiation biophysics.

PubMed

Hofstetter, Markus; Howgate, John; Schmid, Martin; Schoell, Sebastian; Sachsenhauser, Matthias; Adigüzel, Denis; Stutzmann, Martin; Sharp, Ian D; Thalhammer, Stefan

2012-07-27

There is an increasing interest in the integration of hybrid bio-semiconductor systems for the non-invasive evaluation of physiological parameters. High quality gallium nitride and its alloys show promising characteristics to monitor cellular parameters. Nevertheless, such applications not only request appropriate sensing capabilities but also the biocompatibility and especially the biofunctionality of materials. Here we show extensive biocompatibility studies of gallium nitride and, for the first time, a biofunctionality assay using ionizing radiation. Analytical sensor devices are used in medical settings, as well as for cell- and tissue engineering. Within these fields, semiconductor devices have increasingly been applied for online biosensing on a cellular and tissue level. Integration of advanced materials such as gallium nitride into these systems has the potential to increase the range of applicability for a multitude of test devices and greatly enhance sensitivity and functionality. However, for such applications it is necessary to optimize cell-surface interactions and to verify the biocompatibility of the semiconductor. In this work, we present studies of mouse fibroblast cell activity grown on gallium nitride surfaces after applying external noxa. Cell-semiconductor hybrids were irradiated with X-rays at air kerma doses up to 250 mGy and the DNA repair dynamics, cell proliferation, and cell growth dynamics of adherent cells were compared to control samples. The impact of ionizing radiation on DNA, along with the associated cellular repair mechanisms, is well characterized and serves as a reference tool for evaluation of substrate effects. The results indicate that gallium nitride does not require specific surface treatments to ensure biocompatibility and suggest that cell signaling is not affected by micro-environmental alterations arising from gallium nitride-cell interactions. The observation that gallium nitride provides no bio-functional influence on the cellular environment confirms that this material is well suited for future biosensing applications without the need for additional chemical surface modification. Copyright © 2012 Elsevier Inc. All rights reserved.

Oxygen miscibility gap and spin glass formation in the pyrochlore Lu{sub 2}Mo{sub 2}O{sub 7}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clark, L.; Ritter, C.; Harrison, A.

2013-07-15

Rare earth (R) molybdate pyrochlores, R{sub 2}Mo{sub 2}O{sub 7}, are of interest as frustrated magnets. Polycrystalline samples of Lu{sub 2}Mo{sub 2}O{sub 7−x} prepared at 1600 °C display a coexistence of cubic pyrochlore phases. Rietveld fits to powder neutron diffraction data and chemical analyses show that the miscibility gap is between a stoichiometric x=0 and an oxygen-deficient x≈0.4 phase. Lu{sub 2}Mo{sub 2}O{sub 7} behaves as a spin glass material, with a divergence of field cooled and zero field cooled DC magnetic susceptibilities at a spin freezing temperature T{sub f}=16 K, that varies with frequency in AC measurements following a Vogel–Fulcher law.more » Lu{sub 2}Mo{sub 2}O{sub 6.6} is more highly frustrated spin glass and has T{sub f}=20 K. - Graphical abstract: The cubic Lu{sub 2}Mo{sub 2}O{sub 7−x} system exhibits a miscibility gap between coexisting pyrochlore phases at 1600 °C. Neutron powder diffraction refinement and chemical analysis shows that the gap separates stoichiometric x=0 and oxygen-deficient x≈0.4 phases. Lu{sub 2}Mo{sub 2}O{sub 7−x} has a frustrated spin glass ground state that is sensitive to the oxygen content. - Highlights: • The cubic Lu{sub 2}Mo{sub 2}O{sub 7−x} system has a miscibility gap between coexisting pyrochlore phases at 1600 °C. • Neutron powder diffraction shows that the gap separates x=0 and oxygen-deficient x≈0.4 phases. • Lu{sub 2}Mo{sub 2}O{sub 7−x} has a frustrated spin glass ground state that is sensitive to the oxygen content.« less

Simulation of Organic Magnetic Resonance Force Microscopy Experiments

DTIC Science & Technology

2006-12-01

Citation of manufacturer’s or trade names does not constitute an official endorsement or approval of the use thereof. Destroy this report when...doubled. In both the 2-D and 3-D cases, we do not sum over a finite spin system but integrate over a spin density. In 3-D the intergral is ∂Fx ∂x = − V...k To determine ∆fc given by equation 3, the intergral in equation 2 must be performed. The integral over all sensitive slices is determined with an

pH-Dependent spin state population and 19F NMR chemical shift via remote ligand protonation in an iron(ii) complex.

PubMed

Gaudette, Alexandra I; Thorarinsdottir, Agnes E; Harris, T David

2017-11-30

An Fe II complex that features a pH-dependent spin state population, by virtue of a variable ligand protonation state, is described. This behavior leads to a highly pH-dependent 19 F NMR chemical shift with a sensitivity of 13.9(5) ppm per pH unit at 37 °C, thereby demonstrating the potential utility of the complex as a 19 F chemical shift-based pH sensor.

On the in vitro biocompatibility of Elgiloy, a co-based alloy, compared to two titanium alloys.

PubMed

Es-Souni, Martha; Fischer-Brandies, Helge; Es-Souni, Mohammed

2003-01-01

The aim of the present investigation was to contribute to an understanding of the effects of surface topography and chemical composition on the corrosion behavior and thus the biocompatibility of Elgiloy (RMO, Denver, CO, USA), a common Co-based alloy. The results are compared with those obtained for a binary NiTi alloy, Neo Sentalloy (GAC, Central Islip, NY, USA) and a beta-III-Ti alloy, TMA (Ormco, Glendora, CA, USA). In the present study, the surface topography and the chemical composition of two different grades of Elgiloy, Blue Elgiloy (soft) and Yellow Elgiloy (ductile), were examined by means of scanning electron microscopy (SEM) and energy-dispersive spectroscopy analysis (EDS). Their corrosion behavior in half-strength Ringer solution and in an artificial saliva solution according to Barrett [1] was investigated using potentiodynamic corrosion testing (PDC). The photometry-based PAN method was used to quantify the released Ni and Co ions. The in vitro biocompatibility of the two grades of Elgiloy was tested in three different cell cultures: in L929, a commercially available mouse fibroblast cell line, and in primary human epithelial cells and fibroblasts. The results of the corrosion testing showed satisfactorily high pitting corrosion potentials but lower repassivation potentials and a strong increase in current density once pitting had occurred. The photometric results revealed the release of Ni and Co ions in both tested electrolytes. The tested native surfaces exhibited numerous grinding and polishing grooves, inclusions and inhomogeneities of the microstructure. After corrosion testing the same surfaces displayed numerous signs of corrosion, especially in areas with microstructural inhomogeneities. In vitro biocompatibility testing showed a substantially reduced dehydrogenase activity in the presence of Elgiloy. The reduced quality of surface finish resulting from the manufacturing process led in the case of the tested Elgiloy types to decreased corrosion resistance with consequently reduced in vitro biocompatibility. In this context it is also conceivable that patients with a proven allergy to nickel, cobalt or chromium may react sensitively to the deployment of this alloy, at least in the surface quality tested by us. From this aspect, the introduction of a binding standard for the surface quality of materials used in orthodontic appliances is urgently recommended.

Probe-Specific Procedure to Estimate Sensitivity and Detection Limits for 19F Magnetic Resonance Imaging.

PubMed

Taylor, Alexander J; Granwehr, Josef; Lesbats, Clémentine; Krupa, James L; Six, Joseph S; Pavlovskaya, Galina E; Thomas, Neil R; Auer, Dorothee P; Meersmann, Thomas; Faas, Henryk M

2016-01-01

Due to low fluorine background signal in vivo, 19F is a good marker to study the fate of exogenous molecules by magnetic resonance imaging (MRI) using equilibrium nuclear spin polarization schemes. Since 19F MRI applications require high sensitivity, it can be important to assess experimental feasibility during the design stage already by estimating the minimum detectable fluorine concentration. Here we propose a simple method for the calibration of MRI hardware, providing sensitivity estimates for a given scanner and coil configuration. An experimental "calibration factor" to account for variations in coil configuration and hardware set-up is specified. Once it has been determined in a calibration experiment, the sensitivity of an experiment or, alternatively, the minimum number of required spins or the minimum marker concentration can be estimated without the need for a pilot experiment. The definition of this calibration factor is derived based on standard equations for the sensitivity in magnetic resonance, yet the method is not restricted by the limited validity of these equations, since additional instrument-dependent factors are implicitly included during calibration. The method is demonstrated using MR spectroscopy and imaging experiments with different 19F samples, both paramagnetically and susceptibility broadened, to approximate a range of realistic environments.

Anisotropic rotational diffusion studied by passage saturation transfer electron paramagnetic resonance

NASA Astrophysics Data System (ADS)

Robinson, Bruce H.; Dalton, Larry R.

1980-01-01

The stochastic Liouville equation for the spin density matrix is modified to consider the effects of Brownian anisotropic rotational diffusion upon electron paramagnetic resonance (EPR) and saturation transfer electron paramagnetic resonance (ST-EPR) spectra. Spectral shapes and the ST-EPR parameters L″/L, C'/C, and H″/H defined by Thomas, Dalton, and Hyde at X-band microwave frequencies [J. Chem. Phys. 65, 3006 (1976)] are examined and discussed in terms of the rotational times τ∥ and τ⊥ and in terms of other defined correlation times for systems characterized by magnetic tensors of axial symmetry and for systems characterized by nonaxially symmetric magnetic tensors. For nearly axially symmetric magnetic tensors, such as nitroxide spin labels studied employing 1-3 GHz microwaves, ST-EPR spectra for systems undergoing anisotropic rotational diffusion are virtually indistinguishable from spectra for systems characterized by isotropic diffusion. For nonaxially symmetric magnetic tensors, such as nitroxide spin labels studied employing 8-35 GHz microwaves, the high field region of the ST-EPR spectra, and hence the H″/H parameter, will be virtually indistinguishable from spectra, and parameter values, obtained for isotropic diffusion. On the other hand, the central spectral region at x-band microwave frequencies, and hence the C'/C parameter, is sensitive to the anisotropic diffusion model provided that a unique and static relationship exists between the magnetic and diffusion tensors. Random labeling or motion of the spin label relative to the biomolecule whose hydrodynamic properties are to be investigated will destroy spectral sensitivity to anisotropic motion. The sensitivity to anisotropic motion is enhanced in proceeding to 35 GHz with the increased sensitivity evident in the low field half of the EPR and ST-EPR spectra. The L″/L parameter is thus a meaningful indicator of anisotropic motion when compared with H″/H parameter analysis. However, consideration of spectral shapes suggests that the C'/C parameter definition is not meaningfully extended from 9.5 to 35 GHz. Alternative definitions of the L″/L and C'/C parameters are proposed for those microwave frequencies for which the electron Zeeman anisotropy is comparable to or greater than the electron-nitrogen nuclear hyperfine anisotropy.

300 MHz continuous wave electron paramagnetic resonance spectrometer for small animal in vivo imaging

NASA Astrophysics Data System (ADS)

Koscielniak, J.; Devasahayam, N.; Moni, M. S.; Kuppusamy, P.; Yamada, K.; Mitchell, J. B.; Krishna, M. C.; Subramanian, S.

2000-11-01

Design and construction of an electron paramagnetic resonance (EPR) spectrometer, operating in the continuous wave mode in the radio frequency (rf) region, and capable of performing spectroscopy and in vivo imaging of paramagnetic spin probes is described. A resonant frequency of 300 MHz was chosen to provide the required sensitivity at nontoxic levels of commonly used spin probes and penetration of the rf in small animals. Three major components, the magnet, the radio frequency signal detection bridge, and the data acquisition module are described in this article. Integration of a rapid scan capability to reduce imaging time is also described. Two- and three-dimensional EPR images of the spin probe distribution in phantom objects as well as from in vivo experiments are reported. From the EPR images, morphology of some internal organs could be recognized. EPR images of the spin probe distribution in mice suggest differences in perfusion of the spin probe between normal and tumor regions. Addition of a spectral dimension to spatial images should enable differentiation of oxygen status in normal and pathological conditions.

Site-specific detection of radicals on α-lactalbumin after a riboflavin-sensitized reaction, detected by immuno-spin trapping, ESR, and MS.

PubMed

Dalsgaard, Trine K; Triquigneaux, Mathilde; Deterding, Leesa; Summers, Fiona; Ranguelova, Kalina; Mortensen, Grith; Mason, Ronald P

2013-01-16

Free radicals and other oxidation products were characterized on α-lactalbumin with electron spin resonance (ESR), immuno-spin trapping, and mass spectrometry (MS) after riboflavin-mediated oxidation. Radicals were detected using the spin trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO) in immuno-spin trapping with both enzyme-linked immunosorbent assay (ELISA) and Western blotting and further characterized with mass spectrometry. A DMPO-trapped radical was identified at His68 and another at one of the tyrosine residues, Tyr50 or Tyr36, respectively, generated by a type II or I mechanism. Not all tyrosyl radicals were trapped, as the secondary oxidation product, 3,4-dihydroxyphenylalanine (DOPA), was detected by mass spectrometry at Tyr18 and Tyr50. A further oxidation of DOPA resulted in the DOPA o-semiquinone radical, which was characterized by ESR. Both surface exposure and the neighboring residues in the local environment of the tertiary structure of α-lactalbumin seem to play a role in the generation of DMPO trapped radicals and secondary oxidation products.

Selective One-Dimensional Total Correlation Spectroscopy Nuclear Magnetic Resonance Experiments for a Rapid Identification of Minor Components in the Lipid Fraction of Milk and Dairy Products: Toward Spin Chromatography?

PubMed

Papaemmanouil, Christina; Tsiafoulis, Constantinos G; Alivertis, Dimitrios; Tzamaloukas, Ouranios; Miltiadou, Despoina; Tzakos, Andreas G; Gerothanassis, Ioannis P

2015-06-10

We report a rapid, direct, and unequivocal spin-chromatographic separation and identification of minor components in the lipid fraction of milk and common dairy products with the use of selective one-dimensional (1D) total correlation spectroscopy (TOCSY) nuclear magnetic resonance (NMR) experiments. The method allows for the complete backbone spin-coupling network to be elucidated even in strongly overlapped regions and in the presence of major components from 4 × 10(2) to 3 × 10(3) stronger NMR signal intensities. The proposed spin-chromatography method does not require any derivatization steps for the lipid fraction, is selective with excellent resolution, is sensitive with quantitation capability, and compares favorably to two-dimensional (2D) TOCSY and gas chromatography-mass spectrometry (GC-MS) methods of analysis. The results of the present study demonstrated that the 1D TOCSY NMR spin-chromatography method can become a procedure of primary interest in food analysis and generally in complex mixture analysis.

Reduction process of nitroxyl spin probes used in Overhauser-enhanced magnetic resonance imaging: An ESR study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meenakumari, V.; Premkumar, S.; Benial, A. Milton Franklin, E-mail: miltonfranklin@yahoo.com

The Electron spin resonance studies on the reduction process of nitroxyl spin probes were carried out for 1mM {sup 14}N- labeled nitroxyl radicals in pure water and 1 mM concentration of ascorbic acid as a function of time. The electron spin resonance parameters, such as line width, hyperfine coupling constant, g-factor, signal intensity ratio and rotational correlation time were estimated. The 3-carbamoyl-PROXYL radical has narrowest line width and fast tumbling motion compared with 3-carboxy-PROXYL, 4-methoxy-TEMPO, and 4-acetamido-TEMPO radicals. The half life time and decay rate were estimated for 1mM concentration of {sup 14}N- labeled nitroxyl radicals in 1 mM concentration ofmore » ascorbic acid. From the results, the 3-carbamoyl-PROXYL has long half life time and high stability compared with 3-carboxy-PROXYL, 4-methoxy-TEMPO and 4-acetamido-TEMPO radicals. Therefore, this study reveals that the 3-carbamoyl-PROXYL radical can act as a good redox sensitive spin probe for Overhauser-enhanced Magnetic Resonance Imaging.« less

Critical and compensation behavior of a mixed spin-3/2 and spin-5/2 Ising ferrimagnetic system in a graphene layer

NASA Astrophysics Data System (ADS)

Alzate-Cardona, J. D.; Sabogal-Suárez, D.; Restrepo-Parra, E.

2017-05-01

We have studied the magnetic properties of the mixed spin σ = ± 3/2, ± 1/2 and spin S = ± 5/2, ± 3/2, ± 1/2 Ising ferrimagnetic system in a graphene layer by means of Monte Carlo simulations. The effects of next-nearest neighbors exchange interactions and crystal field anisotropy on the critical and compensation behavior of the system have been investigated. The results show that, for a system with given values of the crystal field anisotropy and exchange interaction constants, a compensation point only exists if the values of the spins in the ground state are such that | S | > | σ | and Jσ is higher than a certain value Jσmin . It was shown that the relationship between Jσmin and JS is linear for a given value of the crystal field constant. The compensation and the critical temperature are very sensitive to the change of JS and Jσ, respectively, while the crystal field anisotropy affects both temperatures to a large extent.

Reorientation of the diagonal double-stripe spin structure at Fe 1+yTe bulk and thin-film surfaces

DOE PAGES

Hanke, Torben; Singh, Udai Raj; Cornils, Lasse; ...

2017-01-06

Here, establishing the relation between ubiquitous antiferromagnetism in the parent compounds of unconventional superconductors and their superconducting phase is important for understanding the complex physics in these materials. Going from bulk systems to thin films additionally affects their phase diagram. For Fe 1+yTe, the parent compound of Fe 1+ySe 1$-x$Tex superconductors, bulk-sensitive neutron diffraction revealed an in-plane oriented diagonal double-stripe antiferromagnetic spin structure. Here we show by spin-resolved scanning tunnelling microscopy that the spin direction at the surfaces of bulk Fe 1+yTe and thin films grown on the topological insulator Bi 2Te 3 is canted out of the high-symmetry directionsmore » of the surface unit cell resulting in a perpendicular spin component, keeping the diagonal double-stripe order. As the magnetism of the Fe d-orbitals is intertwined with the superconducting pairing in Fe-based materials, our results imply that the superconducting properties at the surface of the related superconducting compounds might be different from the bulk.« less

Reorientation of the diagonal double-stripe spin structure at Fe 1+yTe bulk and thin-film surfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hanke, Torben; Singh, Udai Raj; Cornils, Lasse

Here, establishing the relation between ubiquitous antiferromagnetism in the parent compounds of unconventional superconductors and their superconducting phase is important for understanding the complex physics in these materials. Going from bulk systems to thin films additionally affects their phase diagram. For Fe 1+yTe, the parent compound of Fe 1+ySe 1$-x$Tex superconductors, bulk-sensitive neutron diffraction revealed an in-plane oriented diagonal double-stripe antiferromagnetic spin structure. Here we show by spin-resolved scanning tunnelling microscopy that the spin direction at the surfaces of bulk Fe 1+yTe and thin films grown on the topological insulator Bi 2Te 3 is canted out of the high-symmetry directionsmore » of the surface unit cell resulting in a perpendicular spin component, keeping the diagonal double-stripe order. As the magnetism of the Fe d-orbitals is intertwined with the superconducting pairing in Fe-based materials, our results imply that the superconducting properties at the surface of the related superconducting compounds might be different from the bulk.« less

An optimized velocity selective arterial spin labeling module with reduced eddy current sensitivity for improved perfusion quantification.

PubMed

Meakin, James A; Jezzard, Peter

2013-03-01

Velocity-selective (VS) arterial spin labeling is a promising method for measuring perfusion in areas of slow or collateral flow by eliminating the bolus arrival delay associated with other spin labeling techniques. However, B(0) and B(1) inhomogeneities and eddy currents during the VS preparation hinder accurate quantification of perfusion with VS arterial spin labeling. In this study, it is demonstrated through simulations and experiments in healthy volunteers that eddy currents cause erroneous tagging of static tissue. Consequently, mean gray matter perfusion is overestimated by up to a factor of 2, depending on the VS preparation used. A novel eight-segment B(1) insensitive rotation VS preparation is proposed to reduce eddy current effects while maintaining the B(0) and B(1) insensitivity of previous preparations. Compared to two previous VS preparations, the eight-segment B(1) insensitive rotation is the most robust to eddy currents and should improve the quality and reliability of VS arterial spin labeling measurements in future studies. Copyright © 2012 Wiley Periodicals, Inc.

Reduction process of nitroxyl spin probes used in Overhauser-enhanced magnetic resonance imaging: An ESR study

NASA Astrophysics Data System (ADS)

Meenakumari, V.; Jawahar, A.; Premkumar, S.; Benial, A. Milton Franklin

2016-05-01

The Electron spin resonance studies on the reduction process of nitroxyl spin probes were carried out for 1mM 14N- labeled nitroxyl radicals in pure water and 1 mM concentration of ascorbic acid as a function of time. The electron spin resonance parameters, such as line width, hyperfine coupling constant, g-factor, signal intensity ratio and rotational correlation time were estimated. The 3-carbamoyl-PROXYL radical has narrowest line width and fast tumbling motion compared with 3-carboxy-PROXYL, 4-methoxy-TEMPO, and 4-acetamido-TEMPO radicals. The half life time and decay rate were estimated for 1mM concentration of 14N- labeled nitroxyl radicals in 1 mM concentration of ascorbic acid. From the results, the 3-carbamoyl-PROXYL has long half life time and high stability compared with 3-carboxy-PROXYL, 4-methoxy-TEMPO and 4-acetamido-TEMPO radicals. Therefore, this study reveals that the 3-carbamoyl-PROXYL radical can act as a good redox sensitive spin probe for Overhauser-enhanced Magnetic Resonance Imaging.

Perfusion deficits detected by arterial spin-labeling in patients with TIA with negative diffusion and vascular imaging.

PubMed

Qiao, X J; Salamon, N; Wang, D J J; He, R; Linetsky, M; Ellingson, B M; Pope, W B

2013-01-01

A substantial portion of clinically diagnosed TIA cases is imaging-negative. The purpose of the current study is to determine if arterial spin-labeling is helpful in detecting perfusion abnormalities in patients presenting clinically with TIA. Pseudocontinuous arterial spin-labeling with 3D background-suppressed gradient and spin-echo was acquired on 49 patients suspected of TIA within 24 hours of symptom onset. All patients were free of stroke history and had no lesion-specific findings on general MR, DWI, and MRA sequences. The calculated arterial spin-labeling CBF maps were scored from 1-3 on the basis of presence and severity of perfusion disturbance by 3 independent observers blinded to patient history. An age-matched cohort of 36 patients diagnosed with no cerebrovascular events was evaluated as a control. Interobserver agreement was assessed by use of the Kendall concordance test. Scoring of perfusion abnormalities on arterial spin-labeling scans of the TIA cohort was highly concordant among the 3 observers (W = 0.812). The sensitivity and specificity of arterial spin-labeling in the diagnosis of perfusion abnormalities in TIA was 55.8% and 90.7%, respectively. In 93.3% (70/75) of the arterial spin-labeling CBF map readings with positive scores (≥2), the brain regions where perfusion abnormalities were identified by 3 observers matched with the neurologic deficits at TIA onset. In this preliminary study, arterial spin-labeling showed promise in the detection of perfusion abnormalities that correlated with clinically diagnosed TIA in patients with otherwise normal neuroimaging results.

Engineering Gd-loaded nanoparticles to enhance MRI sensitivity via T1 shortening

NASA Astrophysics Data System (ADS)

Bruckman, Michael A.; Yu, Xin; Steinmetz, Nicole F.

2013-11-01

Magnetic resonance imaging (MRI) is a noninvasive imaging technique capable of obtaining high-resolution anatomical images of the body. Major drawbacks of MRI are the low contrast agent sensitivity and inability to distinguish healthy tissue from diseased tissue, making early detection challenging. To address this technological hurdle, paramagnetic contrast agents have been developed to increase the longitudinal relaxivity, leading to an increased signal-to-noise ratio. This review focuses on methods and principles that enabled the design and engineering of nanoparticles to deliver contrast agents with enhanced ionic relaxivities. Different engineering strategies and nanoparticle platforms will be compared in terms of their manufacturability, biocompatibility properties, and their overall potential to make an impact in clinical MR imaging.

Stimuli-Responsive NO Release for On-Demand Gas-Sensitized Synergistic Cancer Therapy.

PubMed

Fan, Wenpei; Yung, Bryant C; Chen, Xiaoyuan

2018-03-08

Featuring high biocompatibility, the emerging field of gas therapy has attracted extensive attention in the medical and scientific communities. Currently, considerable research has focused on the gasotransmitter nitric oxide (NO) owing to its unparalleled dual roles in directly killing cancer cells at high concentrations and cooperatively sensitizing cancer cells to other treatments for synergistic therapy. Of particular note, recent state-of-the-art studies have turned our attention to the chemical design of various endogenous/exogenous stimuli-responsive NO-releasing nanomedicines and their biomedical applications for on-demand NO-sensitized synergistic cancer therapy, which are discussed in this Minireview. Moreover, the potential challenges regarding NO gas therapy are also described, aiming to advance the development of NO nanomedicines as well as usher in new frontiers in this fertile research area. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of cubic Dresselhaus interaction on the longitudinal optical conductivity of a spin-orbit coupled system

NASA Astrophysics Data System (ADS)

Cruz, Elmer; López-Bastidas, Catalina; Maytorena, Jesús A.

2018-03-01

We investigate the effect of the oft-neglected cubic terms of the Dresselhaus spin-orbit coupling on the longitudinal current response of a two-dimensional electron gas with both Rashba and linear Dresselhaus interactions. For a quantum well grown in the [001] direction, the changes caused by these nonlinear-in-momentum terms on the absorption spectrum become more notable under SU(2) symmetry conditions, when the Rashba and linear Dresselhaus coupling strengths are tuned to be equal. The longitudinal optical response no longer vanishes then and shows a strong dependence on the direction of the externally applied electric field, giving a signature of the relative size of several spin-orbit contributions. This anisotropic response arises from the nonisotropic splitting of the spin states induced by the interplay of Rashba and Dresselhaus couplings. However, the presence of cubic terms introduces characteristic spectral features and can modify the overall shape of the spectra for some values of the relative sizes of the spin-orbit parameters. We compare this behavior to the case of a sample with [110] crystal orientation which, under conditions of spin-preserving symmetry, has a collinear spin-orbit vector field that leads to vanishing conductivity, even in the presence of cubic terms. In addition to the control through the driven frequency or electrical gating, such a directional aspect of the current response suggests new ways of manipulation and supports the use of interband optics as a sensitive probe of spin-orbit mechanisms in semiconductor spintronics.

Feedback-tuned, noise resilient gates for encoded spin qubits

NASA Astrophysics Data System (ADS)

Bluhm, Hendrik

Spin 1/2 particles form native two level systems and thus lend themselves as a natural qubit implementation. However, encoding a single qubit in several spins entails benefits, such as reducing the resources necessary for qubit control and protection from certain decoherence channels. While several varieties of such encoded spin qubits have been implemented, accurate control remains challenging, and leakage out of the subspace of valid qubit states is a potential issue. Optimal performance typically requires large pulse amplitudes for fast control, which is prone to systematic errors and prohibits standard control approaches based on Rabi flopping. Furthermore, the exchange interaction typically used to electrically manipulate encoded spin qubits is inherently sensitive to charge noise. I will discuss all-electrical, high-fidelity single qubit operations for a spin qubit encoded in two electrons in a GaAs double quantum dot. Starting from a set of numerically optimized control pulses, we employ an iterative tuning procedure based on measured error syndromes to remove systematic errors.Randomized benchmarking yields an average gate fidelity exceeding 98 % and a leakage rate into invalid states of 0.2 %. These gates exhibit a certain degree of resilience to both slow charge and nuclear spin fluctuations due to dynamical correction analogous to a spin echo. Furthermore, the numerical optimization minimizes the impact of fast charge noise. Both types of noise make relevant contributions to gate errors. The general approach is also adaptable to other qubit encodings and exchange based two-qubit gates.

Slow dynamics in the geometrically frustrated magnet ZnFe2O4: Universal features of aging phenomena in spin glasses

NASA Astrophysics Data System (ADS)

Mamiya, H.; Tsujii, N.; Terada, N.; Nimori, S.; Kitazawa, H.; Hoshikawa, A.; Ishigaki, T.

2014-07-01

To clarify the universal features of spin glasses, we carefully studied slow dynamics in a geometrically frustrated magnet ZnFe2O4 with slight disorders, regarded as an "unconventional" Heisenberg spin glass, using time-resolved neutron diffractometry and magnetometry. The results indicate that "aging" can be attributed not to growth of the short-range order detected by a diffuse scattering but to aging of a hidden aperiodic correlation, as expected from theories for spin glasses. Concerning aging, peculiar behavior was found; the decay of thermoremanent magnetization is extremely accelerated if the sample is heated/cooled briefly midway through the isothermal slow relaxation. Conversely, magnetization surprisingly increases despite the absence of a magnetic field when the temperature returns after the brief heating/cooling. The behavior can be explained as a destabilization of the aged spin configuration due to the thermal perturbations and subsequent spontaneous restoration of the original spin configuration after the destabilization. Whereas such destabilization and restoration do not occur during freezing into numerous metastable states in a fixed energy landscape, these are possible in an energy landscape with a temperature-sensitive funnel-like structure. These features, consistent with the ghost domain scenario of the droplet picture, are the same as for conventional Heisenberg spin glasses such as dilute magnetic alloys and dilute magnetic semiconductors. In other words, they are universal features in Heisenberg spin glasses including unconventional ones.

Magnon rainbows filtered through phonon clouds

NASA Astrophysics Data System (ADS)

Boona, Stephen R.

2016-06-01

The study of heat flow in magnetic insulators is a topic of significant interest in spin caloritronics, especially for understanding the nuanced origins of the spin Seebeck effect (SSE). Recent work by Diniz and Costa (2016 New J. Phys. 18 052002) provides insight into this subject by presenting a microscopic model for the spectral dependence of magnon-phonon interactions in magnetic insulators, which has been a challenging puzzle for decades. Their new paper shows that phonon-mediated magnon-magnon interactions affect the lifetime of magnons differently depending on the magnon wavelength. As a result, low energy magnons transport spin more efficiently, and are more sensitive to applied magnetic fields. These results help explain some unexpected behavior in the SSE recently reported in several experiments.

Measurement of the Generalized Forward Spin Polarizabilities of the Neutron

NASA Astrophysics Data System (ADS)

Amarian, M.; Auerbach, L.; Averett, T.; Berthot, J.; Bertin, P.; Bertozzi, W.; Black, T.; Brash, E.; Brown, D.; Burtin, E.; Calarco, J.; Cates, G.; Chai, Z.; Chen, J.-P.; Choi, Seonho; Chudakov, E.; Cisbani, E.; de Jager, C. W.; Deur, A.; Disalvo, R.; Dieterich, S.; Djawotho, P.; Finn, J. M.; Fissum, K.; Fonvieille, H.; Frullani, S.; Gao, H.; Gao, J.; Garibaldi, F.; Gasparian, A.; Gilad, S.; Gilman, R.; Glamazdin, A.; Glashausser, C.; Goldberg, E.; Gomez, J.; Gorbenko, V.; Hansen, J.-O.; Hersman, B.; Holmes, R.; Huber, G. M.; Hughes, E.; Humensky, B.; Incerti, S.; Iodice, M.; Jensen, S.; Jiang, X.; Jones, C.; Jones, G.; Jones, M.; Jutier, C.; Ketikyan, A.; Kominis, I.; Korsch, W.; Kramer, K.; Kumar, K.; Kumbartzki, G.; Kuss, M.; Lakuriqi, E.; Laveissiere, G.; Lerose, J.; Liang, M.; Liyanage, N.; Lolos, G.; Malov, S.; Marroncle, J.; McCormick, K.; McKeown, R.; Meziani, Z.-E.; Michaels, R.; Mitchell, J.; Papandreou, Z.; Pavlin, T.; Petratos, G. G.; Pripstein, D.; Prout, D.; Ransome, R.; Roblin, Y.; Rowntree, D.; Rvachev, M.; Sabatie, F.; Saha, A.; Slifer, K.; Souder, P.; Saito, T.; Strauch, S.; Suleiman, R.; Takahashi, K.; Teijiro, S.; Todor, L.; Tsubota, H.; Ueno, H.; Urciuoli, G.; der Meer, R. Van; Vernin, P.; Voskanian, H.; Wojtsekhowski, B.; Xiong, F.; Xu, W.; Yang, J.-C.; Zhang, B.; Żołnierczuk, P. A.

2004-10-01

The generalized forward spin polarizabilities γ0 and δLT of the neutron have been extracted for the first time in a Q2 range from 0.1 to 0.9 GeV2. Since γ0 is sensitive to nucleon resonances and δLT is insensitive to the Δ resonance, it is expected that the pair of forward spin polarizabilities should provide benchmark tests of the current understanding of the chiral dynamics of QCD. The new results on δLT show significant disagreement with chiral perturbation theory calculations, while the data for γ0 at low Q2 are in good agreement with a next-to-leading-order relativistic baryon chiral perturbation theory calculation. The data show good agreement with the phenomenological MAID model.

Spin disorder in maghemite nanoparticles investigated using polarized neutrons and nuclear resonant scattering

NASA Astrophysics Data System (ADS)

Herlitschke, M.; Disch, S.; Sergueev, I.; Schlage, K.; Wetterskog, E.; Bergström, L.; Hermann, R. P.

2016-04-01

The manuscript reports the investigation of spin disorder in maghemite nanoparticles of different shape by a combination of polarized small-angle neutron scattering (SANSPOL) and nuclear forward scattering (NFS) techniques. Both methods are sensitive to magnetization on the nanoscale. SANSPOL allows for investigation of the particle morphology and spatial magnetization distribution and NFS extends this nanoscale information to the atomic scale, namely the orientation of the hyperfine field experienced by the iron nuclei. The studied nanospheres and nanocubes with diameters of 7.4 nm and 10.6 nm, respectively, exhibit a significant spin disorder. This effect leads to a reduction of the magnetization to 44% and 58% of the theoretical maghemite bulk value, observed consistently by both techniques.

High-Frequency Fe-H Vibrations in a Bridging Hydride Complex Characterized by NRVS and DFT.

PubMed

Pelmenschikov, Vladimir; Gee, Leland B; Wang, Hongxin; MacLeod, K Cory; McWilliams, Sean F; Skubi, Kazimer L; Cramer, Stephen P; Holland, Patrick L

2018-05-30

High-spin iron species with bridging hydrides have been detected in species trapped during nitrogenase catalysis, but there are few general methods of evaluating Fe-H bonds in high-spin multinuclear iron systems. An 57 Fe nuclear resonance vibrational spectroscopy (NRVS) study on an Fe(μ-H) 2 Fe model complex reveals Fe-H stretching vibrations for bridging hydrides at frequencies greater than 1200 cm -1 . These isotope-sensitive vibrational bands are not evident in infrared (IR) spectra, showing the power of NRVS for identifying hydrides in this high-spin iron system. Complementary density functional theory (DFT) calculations elucidate the normal modes of the rhomboidal iron hydride core. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Using polarized muons as ultrasensitive spin labels in free radical chemistry

NASA Astrophysics Data System (ADS)

McKenzie, Iain; Roduner, Emil

2009-08-01

In a chemical sense, the positive muon is a light proton. It is obtained at the ports of accelerators in beams with a spin polarization of 100%, which makes it a highly sensitive probe of matter. The muonium atom is a light hydrogen isotope, nine times lighter than H, with a muon as its nucleus. It reacts the same way as H, and by addition to double bonds it is implemented in free radicals in which the muon serves as a fully polarized spin label. It is reviewed here how the muon can be used to obtain information about muonium and radical reaction rates, radical structure, dynamics, and local environments. It can even tell us what a fragrance molecule does in a shampoo.

Local and global Λ polarization in a vortical fluid

DOE PAGES

Li, Hui; Petersen, Hannah; Pang, Long -Gang; ...

2017-09-25

We compute the fermion spin distribution in the vortical fluid created in off-central high energy heavy-ion collisions. We employ the event-by-event (3+1)D viscous hydrodynamic model. The spin polarization density is proportional to the local fluid vorticity in quantum kinetic theory. As a result of strong collectivity, the spatial distribution of the local vorticity on the freeze-out hyper-surface strongly correlates to the rapidity and azimuthal angle distribution of fermion spins. We investigate the sensitivity of the local polarization to the initial fluid velocity in the hydrodynamic model and compute the global polarization of Λ hyperons by the AMPT model. The energymore » dependence of the global polarization agrees with the STAR data.« less

Local and global Λ polarization in a vortical fluid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Hui; Petersen, Hannah; Pang, Long -Gang

We compute the fermion spin distribution in the vortical fluid created in off-central high energy heavy-ion collisions. We employ the event-by-event (3+1)D viscous hydrodynamic model. The spin polarization density is proportional to the local fluid vorticity in quantum kinetic theory. As a result of strong collectivity, the spatial distribution of the local vorticity on the freeze-out hyper-surface strongly correlates to the rapidity and azimuthal angle distribution of fermion spins. We investigate the sensitivity of the local polarization to the initial fluid velocity in the hydrodynamic model and compute the global polarization of Λ hyperons by the AMPT model. The energymore » dependence of the global polarization agrees with the STAR data.« less

Spin-exchange relaxation-free magnetometer with nearly parallel pump and probe beams

DOE PAGES

Karaulanov, Todor; Savukov, Igor; Kim, Young Jin

2016-03-22

We constructed a spin-exchange relaxation-free (SERF) magnetometer with a small angle between the pump and probe beams facilitating a multi-channel design with a flat pancake cell. This configuration provides almost complete overlap of the beams in the cell, and prevents the pump beam from entering the probe detection channel. By coupling the lasers in multi-mode fibers, without an optical isolator or field modulation, we demonstrate a sensitivity of 10 fTmore » $$/\\sqrt{\\text{Hz}}$$ for frequencies between 10 Hz and 100 Hz. In addition to the experimental study of sensitivity, we present a theoretical analysis of SERF magnetometer response to magnetic fields for small-angle and parallel-beam configurations, and show that at optimal DC offset fields the magnetometer response is comparable to that in the orthogonal-beam configuration. Based on the analysis, we also derive fundamental and probe-limited sensitivities for the arbitrary non-orthogonal geometry. The expected practical and fundamental sensitivities are of the same order as those in the orthogonal geometry. As a result, we anticipate that our design will be useful for magnetoencephalography (MEG) and magnetocardiography (MCG) applications.« less

Galaxy bispectrum from massive spinning particles

NASA Astrophysics Data System (ADS)

Moradinezhad Dizgah, Azadeh; Lee, Hayden; Muñoz, Julian B.; Dvorkin, Cora

2018-05-01

Massive spinning particles, if present during inflation, lead to a distinctive bispectrum of primordial perturbations, the shape and amplitude of which depend on the masses and spins of the extra particles. This signal, in turn, leaves an imprint in the statistical distribution of galaxies; in particular, as a non-vanishing galaxy bispectrum, which can be used to probe the masses and spins of these particles. In this paper, we present for the first time a new theoretical template for the bispectrum generated by massive spinning particles, valid for a general triangle configuration. We then proceed to perform a Fisher-matrix forecast to assess the potential of two next-generation spectroscopic galaxy surveys, EUCLID and DESI, to constrain the primordial non-Gaussianity sourced by these extra particles. We model the galaxy bispectrum using tree-level perturbation theory, accounting for redshift-space distortions and the Alcock-Paczynski effect, and forecast constraints on the primordial non-Gaussianity parameters marginalizing over all relevant biases and cosmological parameters. Our results suggest that these surveys would potentially be sensitive to any primordial non-Gaussianity with an amplitude larger than fNL≈ 1, for massive particles with spins 2, 3, and 4. Interestingly, if non-Gaussianities are present at that level, these surveys will be able to infer the masses of these spinning particles to within tens of percent. If detected, this would provide a very clear window into the particle content of our Universe during inflation.

Broadband Transmission EPR Spectroscopy

PubMed Central

Hagen, Wilfred R.

2013-01-01

EPR spectroscopy employs a resonator operating at a single microwave frequency and phase-sensitive detection using modulation of the magnetic field. The X-band spectrometer is the general standard with a frequency in the 9–10 GHz range. Most (bio)molecular EPR spectra are determined by a combination of the frequency-dependent electronic Zeeman interaction and a number of frequency-independent interactions, notably, electron spin – nuclear spin interactions and electron spin – electron spin interactions, and unambiguous analysis requires data collection at different frequencies. Extant and long-standing practice is to use a different spectrometer for each frequency. We explore the alternative of replacing the narrow-band source plus single-mode resonator with a continuously tunable microwave source plus a non-resonant coaxial transmission cell in an unmodulated external field. Our source is an arbitrary wave digital signal generator producing an amplitude-modulated sinusoidal microwave in combination with a broadband amplifier for 0.8–2.7 GHz. Theory is developed for coaxial transmission with EPR detection as a function of cell dimensions and materials. We explore examples of a doublet system, a high-spin system, and an integer-spin system. Long, straigth, helical, and helico-toroidal cells are developed and tested with dilute aqueous solutions of spin label hydroxy-tempo. A detection limit of circa 5 µM HO-tempo in water at 800 MHz is obtained for the present setup, and possibilities for future improvement are discussed. PMID:23555819

Magnetic order at a single-crystal surface in the diffuse-scattering theory

NASA Astrophysics Data System (ADS)

Zasada, I.

2003-06-01

A theoretical description of incoherent spin-dependent multiple scattering of electrons at a magnetically disordered single-crystal surface is reported. A formalism in which the spin operators specify the magnetic state of a surface atom is used for the description of magnetic order at the surface. The theory is based upon the concepts used in multiple scattering spin-dependent diffuse LEED theory (DSPLEED) theory. In the present considerations, this theory is extended to the case of magnetic materials by using the time-independent Dirac equation with an effective magnetic field. Thus, an expression for incoherent spin-dependent intensity for magnetic material is obtained. It depends on the Fourier transform on the surface lattice of the spin-pair correlation function and, as a consequence, on the magnetic properties of the surface. The equations for the description of magnetization and various correlation functions in the frame of effective field theory are derived and the results of the numerical calculations are presented for the particular case of Ni(1 0 0) surface. The spin-orbit induced and exchange asymmetries are calculated. It is found that the magnetic DSPLEED is sensitive to the properties of the surface characterized by the spin-pair correlation functions. Thus, it is demonstrated that the magnetic DSPLEED can be an effective method in the investigation of critical behaviour of magnetic surfaces.

Low-temperature dynamic nuclear polarization at 9.4 T with a 30 mW microwave source.

PubMed

Thurber, Kent R; Yau, Wai-Ming; Tycko, Robert

2010-06-01

Dynamic nuclear polarization (DNP) can provide large signal enhancements in nuclear magnetic resonance (NMR) by transfer of polarization from electron spins to nuclear spins. We discuss several aspects of DNP experiments at 9.4 T (400 MHz resonant frequency for (1)H, 264 GHz for electron spins in organic radicals) in the 7-80K temperature range, using a 30 mW, frequency-tunable microwave source and a quasi-optical microwave bridge for polarization control and low-loss microwave transmission. In experiments on frozen glycerol/water doped with nitroxide radicals, DNP signal enhancements up to a factor of 80 are observed (relative to (1)H NMR signals with thermal equilibrium spin polarization). The largest sensitivity enhancements are observed with a new triradical dopant, DOTOPA-TEMPO. Field modulation with a 10 G root-mean-squared amplitude during DNP increases the nuclear spin polarizations by up to 135%. Dependencies of (1)H NMR signal amplitudes, nuclear spin relaxation times, and DNP build-up times on the dopant and its concentration, temperature, microwave power, and modulation frequency are reported and discussed. The benefits of low-temperature DNP can be dramatic: the (1)H spin polarization is increased approximately 1000-fold at 7 K with DNP, relative to thermal polarization at 80K. (c) 2010 Elsevier Inc. All rights reserved.

High Sensitivity Refractometer Based on TiO₂-Coated Adiabatic Tapered Optical Fiber via ALD Technology.

PubMed

Zhu, Shan; Pang, Fufei; Huang, Sujuan; Zou, Fang; Guo, Qiang; Wen, Jianxiang; Wang, Tingyun

2016-08-15

Atomic layer deposition (ALD) technology is introduced to fabricate a high sensitivity refractometer based on an adiabatic tapered optical fiber. Different thicknesses of titanium dioxide (TiO₂) nanofilm were coated around the tapered fiber precisely and uniformly under different deposition cycles. Attributed to the higher refractive index of the TiO₂ nanofilm compared to that of silica, an asymmetric Fabry-Perot (F-P) resonator could be constructed along the fiber taper. The central wavelength of the F-P resonator could be controlled by adjusting the thickness of the TiO₂ nanofilm. Such a F-P resonator is sensitive to changes in the surrounding refractive index (SRI), which is utilized to realize a high sensitivity refractometer. The refractometer developed by depositing 50.9-nm-thickness TiO₂ on the tapered fiber shows SRI sensitivity as high as 7096 nm/RIU in the SRI range of 1.3373-1.3500. Due to TiO₂'s advantages of high refractive index, lack of toxicity, and good biocompatibility, this refractometer is expected to have wide applications in the biochemical sensing field.

[Biocompatibility of peritoneal dialysis fluids].

PubMed

Boulanger, Eric; Moranne, Olivier; Wautier, Marie-Paule; Rougier, Jean-Phillipe; Ronco, Pierre; Pagniez, Dominique; Wautier, Jean-Luc

2005-03-01

Repeated and long-term exposure to conventional glucose-based peritoneal dialysis fluids (PDFs) with poor biocompatibility plays a central role in the pathogenesis of the functional and structural changes of the peritoneal membrane. We have used immortalized human peritoneal mesothelial cells in culture to assess in vitro the biocompatibility of PDFs. Low pH, high glucose concentration and heat sterilization represent major factors of low biocompatibility. Two recent groups of glucose derivatives have been described. Glucose degradation products (GDPs) are formed during heat sterilization (glycoxidation) and storage. GDPs can bind protein and form AGEs (Advanced Glycation End-products), which can also result from the binding of glucose to free NH2 residues of proteins (glycation). The physiological pH, and the separation of glucose during heat sterilization (low GDP content) in the most recent PDFs dramatically increase the biocompatibility. The choice of PD programs with high biocompatibility PDFs allows preserving the function of the peritoneal membrane. Improvement of PDF biocompatibility may limit the occurrence of chronic chemical peritonitis and may allow long-term PD treatment.

High-frequency electron-spin-resonance measurements on Mn x Mg1-x O (x = 1.0×10-4) and DPPH at very low temperatures

NASA Astrophysics Data System (ADS)

Ishikawa, Y.; Ohya, K.; Miura, S.; Fujii, Y.; Mitsudo, S.; Mizusaki, T.; Fukuda, A.; Matsubara, A.; Kikuchi, H.; Asano, T.; Yamamori, H.; Lee, S.; Vasiliev, S.

2018-03-01

We have developed a millimeter-wave electron-spin-resonance (ESR) system for very low temperatures (T < 1 K) that can be employed for nuclear-magnetic-resonance measurements by using dynamic nuclear polarization. The system uses a Fabry-Pérot resonator that works in the frequency range of 125 – 130 GHz and covers the temperature range of 0.09 – 6.5 K. We have performed ESR measurements in the frequency around 128 GHz by using Mn x Mg1-x O (x = 1.0 × 10-4) and free-radical samples of 1, 1-diphenyl-2-picrylhydrazyl (DPPH), because these samples have been proposed as field and sensitivity markers. Temperature dependence of the ESR signal intensity for Mn x Mg1-x O shows anomalies originating from magnetic order are found around 3.5 – 4 K. We estimate the sensitivity of the system for ESR detections to be 6 × 1013 spins/G at 5.8 K. Because DPPH shows no observable shift in the magnetic field, we propose it as a useful standard marker for ESR measurements at very low temperatures.

Bolometer detection of magnetic resonances in nanoscaled objects

NASA Astrophysics Data System (ADS)

Rod, Irina; Meckenstock, Ralf; Zähres, Horst; Derricks, Christian; Mushenok, Fedor; Reckers, Nathalie; Kijamnajsuk, Puchong; Wiedwald, Ulf; Farle, Michael

2014-10-01

We report on a nanoscaled thermocouple (ThC) as a temperature sensor of a highly sensitive bolometer for probing the dissipative damping of spin dynamics in nanosized Permalloy (Py) stripes. The Au-Pd ThC based device is fabricated by standard electron beam lithography on a 200 nm silicon nitride membrane to minimize heat dissipation through the substrate. We show that this thermal sensor allows not only measurements of the temperature change on the order of a few mK due to the uniform resonant microwave (MW) absorption by the Py stripe but also detection of standing spin waves of different mode numbers. Using a 3D finite element method, we estimate the absorbed MW power by the stripe in resonance and prove the necessity of using substrates with an extremely low heat dissipation like a silicon nitride membrane for successful thermal detection. The voltage responsivity and the noise equivalent power for the ThC-based bolometer are equal to 15 V W-1 and 3 nW Hz-1/2, respectively. The ThC device offers a magnetic resonance response of 1 nV/(μB W) corresponding to a sensitivity of 109 spins and a temperature resolution of 300 μK under vacuum conditions.

In vivo study of doxorubicin-loaded cell-penetrating peptide-modified pH-sensitive liposomes: biocompatibility, bio-distribution, and pharmacodynamics in BALB/c nude mice bearing human breast tumors

PubMed Central

Sun, Dan; Wang, Gui-Ling; Hei, Yu; Meng, Shuai; Chen, Jian-Hua; Xie, Ying; Wang, Zhi-Qiang

2017-01-01

In vivo evaluation of drug delivery vectors is essential for clinical translation. In BALB/c nude mice bearing human breast cancer tumors, we investigated the biocompatibility, pharmacokinetics, and pharmacodynamics of doxorubicin (DOX)-loaded novel cell-penetrating peptide (CPP)-modified pH-sensitive liposomes (CPPL) (referred to as CPPL(DOX)) with an optimal CPP density of 4%. In CPPL, a polyethylene glycol (PEG) derivative formed by conjugating PEG with stearate via acid-degradable hydrazone bond (PEG2000-Hz-stearate) was inserted into the surface of liposomes, and CPP was directly attached to liposome surfaces via coupling with stearate to simultaneously achieve long circulation time in blood and improve the selectivity and efficacy of CPP for tumor targeting. Compared to PEGylated liposomes, CPPL enhanced DOX accumulation in tumors up to 1.9-fold (p<0.01) and resulted in more cell apoptosis as a result of DNA disruption as well as a relatively lower tumor growth ratio (T/C%). Histological examination did not show any signs of necrosis or inflammation in normal tissues, but large cell dissolving areas were found in tumors following the treatment of animals with CPPL(DOX). Our findings provide important and detailed information regarding the distribution of CPPL(DOX) in vivo and reveal their abilities of tumor penetration and potential for the treatment of breast cancer. PMID:29123382

Reevaluation of analytical methods for photogenerated singlet oxygen

PubMed Central

Nakamura, Keisuke; Ishiyama, Kirika; Ikai, Hiroyo; Kanno, Taro; Sasaki, Keiichi; Niwano, Yoshimi; Kohno, Masahiro

2011-01-01

The aim of the present study is to compare different analytical methods for singlet oxygen and to discuss an appropriate way to evaluate the yield of singlet oxygen photogenerated from photosensitizers. Singlet oxygen photogenerated from rose bengal was evaluated by electron spin resonance analysis using sterically hindered amines, spectrophotometric analysis of 1,3-diphenylisobenzofuran oxidation, and analysis of fluorescent probe (Singlet Oxygen Sensor Green®). All of the analytical methods could evaluate the relative yield of singlet oxygen. The sensitivity of the analytical methods was 1,3-diphenylisobenzofuran < electron spin resonance < Singlet Oxygen Sensor Green®. However, Singlet Oxygen Sensor Green® could be used only when the concentration of rose bengal was very low (<1 µM). In addition, since the absorption spectra of 1,3-diphenylisobenzofuran is considerably changed by irradiation of 405 nm laser, photosensitizers which are excited by light with a wavelength of around 400 nm such as hematoporphyrin cannot be used in the 1,3-diphenylisobenzofuran oxidation method. On the other hand, electron spin resonance analysis using a sterically hindered amine, especially 2,2,6,6-tetramethyl-4-piperidinol and 2,2,5,5-tetramethyl-3-pyrroline-3-carboxamide, had proper sensitivity and wide detectable range for the yield of photogenerated singlet oxygen. Therefore, in photodynamic therapy, it is suggested that the relative yield of singlet oxygen generated by various photosensitizers can be evaluated properly by electron spin resonance analysis. PMID:21980223

Ultrafast NMR diffusion measurements exploiting chirp spin echoes.

PubMed

Ahola, Susanna; Mankinen, Otto; Telkki, Ville-Veikko

2017-04-01

Standard diffusion NMR measurements require the repetition of the experiment multiple times with varying gradient strength or diffusion delay. This makes the experiment time-consuming and restricts the use of hyperpolarized substances to boost sensitivity. We propose a novel single-scan diffusion experiment, which is based on spatial encoding of two-dimensional data, employing the spin-echoes created by two successive adiabatic frequency-swept chirp π pulses. The experiment is called ultrafast pulsed-field-gradient spin-echo (UF-PGSE). We present a rigorous derivation of the echo amplitude in the UF-PGSE experiment, justifying the theoretical basis of the method. The theory reveals also that the standard analysis of experimental data leads to a diffusion coefficient value overestimated by a few per cent. Although the overestimation is of the order of experimental error and thus insignificant in many practical applications, we propose that it can be compensated by a bipolar gradient version of the experiment, UF-BP-PGSE, or by corresponding stimulated-echo experiment, UF-BP-pulsed-field-gradient stimulated-echo. The latter also removes the effect of uniform background gradients. The experiments offer significant prospects for monitoring fast processes in real time as well as for increasing the sensitivity of experiments by several orders of magnitude by nuclear spin hyperpolarization. Furthermore, they can be applied as basic blocks in various ultrafast multidimensional Laplace NMR experiments. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Sensitivity of new detection method for ultra-low frequency gravitational waves with pulsar spin-down rate statistics

NASA Astrophysics Data System (ADS)

Yonemaru, Naoyuki; Kumamoto, Hiroki; Takahashi, Keitaro; Kuroyanagi, Sachiko

2018-04-01

A new detection method for ultra-low frequency gravitational waves (GWs) with a frequency much lower than the observational range of pulsar timing arrays (PTAs) was suggested in Yonemaru et al. (2016). In the PTA analysis, ultra-low frequency GWs (≲ 10-10 Hz) which evolve just linearly during the observation time span are absorbed by the pulsar spin-down rates since both have the same effect on the pulse arrival time. Therefore, such GWs cannot be detected by the conventional method of PTAs. However, the bias on the observed spin-down rates depends on relative direction of a pulsar and GW source and shows a quadrupole pattern in the sky. Thus, if we divide the pulsars according to the position in the sky and see the difference in the statistics of the spin-down rates, ultra-low frequency GWs from a single source can be detected. In this paper, we evaluate the potential of this method by Monte-Carlo simulations and estimate the sensitivity, considering only the "Earth term" while the "pulsar term" acts like random noise for GW frequencies 10-13 - 10-10 Hz. We find that with 3,000 milli-second pulsars, which are expected to be discovered by a future survey with the Square Kilometre Array, GWs with the derivative of amplitude of about 3 × 10^{-19} {s}^{-1} can in principle be detected. Implications for possible supermassive binary black holes in Sgr* and M87 are also given.

Biosensors Based on Urease Adsorbed on Nickel, Platinum, and Gold Conductometric Transducers Modified with Silicalite and Nanozeolites

NASA Astrophysics Data System (ADS)

Kucherenko, Ivan S.; Soldatkin, Oleksandr O.; Kasap, Berna Ozansoy; Kurç, Burcu Akata; Melnyk, Volodymir G.; Semenycheva, Lyudmila M.; Dzyadevych, Sergei V.; Soldatkin, Alexei P.

This work describes urease-based conductometric biosensors that were created using nontypical method of urease immobilization via adsorption on micro- and nanoporous particles: silicalite and nanocrystalline zeolites Beta (BEA) and L. Conductometric transducers with nickel, gold, and platinum interdigitated electrodes were used. Active regions of the nickel transducers were modified with microparticles using two procedures—spin coating and drop coating. Gold and platinum transducers were modified with silicalite using drop coating since it was more effective. Scanning electron microscopy was used to evaluate effectiveness of these procedures. The procedure of spin coating produced more uniform layers of particles (and biosensors had good reproducibility of preparation), but it was more complicated, drop coating was easier and led to formation of a bulk of particles; thus, biosensors had bigger sensitivity but worse reproducibility of preparation. Urease was immobilized onto transducers modified with particles by physical adsorption. Analytical characteristics of the obtained biosensors for determination of urea (calibration curves, sensitivity, limit of detection, linear concentration range, noise of responses, reproducibility of signal during a day, and operational stability during 3 days) were compared. Biosensors with all three particles deposited by spin coating showed similar characteristics; however, silicalite was a bit more effective. Biosensors based on nickel transducers modified by drop coating had better characteristics in comparison with modification by spin coating (except reproducibility of preparation). Transducers with gold electrodes showed best characteristics while creating biosensors, platinum electrodes were slightly inferior to them, and nickel electrodes were the worst.

SPIN1, negatively regulated by miR-148/152, enhances Adriamycin resistance via upregulating drug metabolizing enzymes and transporter in breast cancer.

PubMed

Chen, Xu; Wang, Ya-Wen; Gao, Peng

2018-05-09

Spindlin1 (SPIN1), a protein highly expressed in several human cancers, has been correlated with tumorigenesis and development. Alterations of drug metabolizing enzymes and drug transporters are major determinants of chemoresistance in tumor cells. However, whether the metabolizing enzymes and transporters are under the control of SPIN1 in breast cancer chemoresistance has not yet been defined. SPIN1 expression in breast cancer cells and tissues was detected by quantitative real-time PCR (qRT-PCR) and immunohistochemistry. Chemosensitivity assays in vitro and in vivo were performed to determine the effect of SPIN1 on Adriamycin resistance. Downstream effectors of SPIN1 were screened by microarray and confirmed by qRT-PCR and Western blot. Luciferase assay and Western blot were used to identify miRNAs regulating SPIN1. We showed that SPIN1 was significantly elevated in drug-resistant breast cancer cell lines and tissues, compared with the chemosensitive ones. SPIN1 enhanced Adriamycin resistance of breast cancer cells in vitro, and downregulation of SPIN1 by miRNA could decrease Adriamycin resistance in vivo. Mechanistically, drug metabolizing enzymes and transporter CYP2C8, UGT2B4, UGT2B17 and ABCB4 were proven to be downstream effectors of SPIN1. Notably, SPIN1 was identified as a direct target of the miR-148/152 family (miR-148a-3p, miR-148b-3p and miR-152-3p). As expected, miR-148a-3p, miR-148b-3p or miR-152-3p could increase Adriamycin sensitivity in breast cancer cells in vitro. Moreover, high expression of SPIN1 or low expression of the miR-148/152 family predicted poorer survival in breast cancer patients. Our results establish that SPIN1, negatively regulated by the miR-148/152 family, enhances Adriamycin resistance in breast cancer via upregulating the expression of drug metabolizing enzymes and drug transporter.

Magnetic field effects in dye-sensitized solar cells controlled by different cell architecture.

PubMed

Klein, M; Pankiewicz, R; Zalas, M; Stampor, W

2016-07-21

The charge recombination and exciton dissociation are generally recognized as the basic electronic processes limiting the efficiency of photovoltaic devices. In this work, we propose a detailed mechanism of photocurrent generation in dye-sensitized solar cells (DSSCs) examined by magnetic field effect (MFE) technique. Here we demonstrate that the magnitude of the MFE on photocurrent in DSSCs can be controlled by the radius and spin coherence time of electron-hole (e-h) pairs which are experimentally modified by the photoanode morphology (TiO2 nanoparticles or nanotubes) and the electronic orbital structure of various dye molecules (ruthenium N719, dinuclear ruthenium B1 and fully organic squaraine SQ2 dyes). The observed MFE is attributed to magnetic-field-induced spin-mixing of (e-h) pairs according to the Δg mechanism.

Characteristic of an Organic Photodetector Fabricated With P3HT:ICBA Blending Materials for Indirect X-Ray Detection

NASA Astrophysics Data System (ADS)

Seon, Hyeji; Kim, Beomsu; Kang, Jungwon

2017-07-01

In this study, an organic conjugated polymer-based photodetector was investigated as a candidate for the indirecttype radiation detector. In order to improve the photon to charge conversion efficiency, we selected the fullerene derivative indeneC60-bisadduct (ICBA) as an n-type semiconductor. The optimal process condition was investigated while varying the P3HT:ICBA blending ratio and spin-rate. The detector at the condition of P3HT:ICBA = 3:2 blending ratio and 900 rpm spin-rate showed the highest sensitivity of 1.35 mC/Gy · cm2 and the highest PCE of 2.93%. Compared to the common P3HT:PCBM detector, the best P3HT:ICBA detector showed 27.36% enhancement of sensitivity and 27.68% enhancement of the PCE.

Magnetic field effects in dye-sensitized solar cells controlled by different cell architecture

NASA Astrophysics Data System (ADS)

Klein, M.; Pankiewicz, R.; Zalas, M.; Stampor, W.

2016-07-01

The charge recombination and exciton dissociation are generally recognized as the basic electronic processes limiting the efficiency of photovoltaic devices. In this work, we propose a detailed mechanism of photocurrent generation in dye-sensitized solar cells (DSSCs) examined by magnetic field effect (MFE) technique. Here we demonstrate that the magnitude of the MFE on photocurrent in DSSCs can be controlled by the radius and spin coherence time of electron-hole (e-h) pairs which are experimentally modified by the photoanode morphology (TiO2 nanoparticles or nanotubes) and the electronic orbital structure of various dye molecules (ruthenium N719, dinuclear ruthenium B1 and fully organic squaraine SQ2 dyes). The observed MFE is attributed to magnetic-field-induced spin-mixing of (e-h) pairs according to the Δg mechanism.

Azimuthal transverse single-spin asymmetries of inclusive jets and charged pions within jets from polarized-proton collisions at s = 500 GeV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adamczyk, L.; Adams, J. R.; Adkins, J. K.

In this paper, we report the first measurements of transverse single-spin asymmetries for inclusive jet and jet+π ± production at midrapidity from transversely polarized proton-proton collisions at √s = 500 GeV. The data were collected in 2011 with the STAR detector sampled from 23 pb -1 integrated luminosity with an average beam polarization of 53%. Asymmetries are reported for jets with transverse momenta 6 < p T < 55 GeV/c and pseudorapidity |η| < 1. Presented are measurements of the inclusive-jet azimuthal transverse single-spin asymmetry, sensitive to twist-3 initial-state quarkgluon correlators; the Collins asymmetry, sensitive to quark transversity coupled tomore » the polarized Collins fragmentation function; and the first measurement of the “Collins-like” asymmetry, sensitive to linearly polarized gluons. Within the present statistical precision, inclusive-jet and Collins-like 3 asymmetries are small, with the latter allowing the first experimental constraints on gluon linear polarization in a polarized proton. At higher values of jet transverse momenta, we observe the first non-zero Collins asymmetries in polarized-proton collisions, with a statistical significance of greater than 5σ. The results span a range of x similar to results from SIDIS but at much higher Q 2. Finally, the Collins results enable tests of universality and factorization-breaking in the transverse momentum-dependent formulation of perturbative quantum chromodynamics.« less

Azimuthal transverse single-spin asymmetries of inclusive jets and charged pions within jets from polarized-proton collisions at s = 500 GeV

DOE PAGES

Adamczyk, L.; Adams, J. R.; Adkins, J. K.; ...

2018-02-02

In this paper, we report the first measurements of transverse single-spin asymmetries for inclusive jet and jet+π ± production at midrapidity from transversely polarized proton-proton collisions at √s = 500 GeV. The data were collected in 2011 with the STAR detector sampled from 23 pb -1 integrated luminosity with an average beam polarization of 53%. Asymmetries are reported for jets with transverse momenta 6 < p T < 55 GeV/c and pseudorapidity |η| < 1. Presented are measurements of the inclusive-jet azimuthal transverse single-spin asymmetry, sensitive to twist-3 initial-state quarkgluon correlators; the Collins asymmetry, sensitive to quark transversity coupled tomore » the polarized Collins fragmentation function; and the first measurement of the “Collins-like” asymmetry, sensitive to linearly polarized gluons. Within the present statistical precision, inclusive-jet and Collins-like 3 asymmetries are small, with the latter allowing the first experimental constraints on gluon linear polarization in a polarized proton. At higher values of jet transverse momenta, we observe the first non-zero Collins asymmetries in polarized-proton collisions, with a statistical significance of greater than 5σ. The results span a range of x similar to results from SIDIS but at much higher Q 2. Finally, the Collins results enable tests of universality and factorization-breaking in the transverse momentum-dependent formulation of perturbative quantum chromodynamics.« less

A high-sensitivity push-pull magnetometer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Breschi, E.; Grujić, Z. D.; Knowles, P.

2014-01-13

We describe our approach to atomic magnetometry based on the push-pull optical pumping technique. Cesium vapor is pumped and probed by a resonant laser beam whose circular polarization is modulated synchronously with the spin evolution dynamics induced by a static magnetic field. The magnetometer is operated in a phase-locked loop, and it has an intrinsic sensitivity below 20fT/√(Hz), using a room temperature paraffin-coated cell. We use the magnetometer to monitor magnetic field fluctuations with a sensitivity of 300fT/√(Hz)

New oxidation treatment of NiTi shape memory alloys to obtain Ni-free surfaces and to improve biocompatibility.

PubMed

Michiardi, A; Aparicio, C; Planell, J A; Gil, F J

2006-05-01

Various oxidation treatments were applied to nearly equiatomic NiTi alloys so as to form a Ni-free protective oxide on the surface. Sample surfaces were analyzed by X-ray Photoelectron Spectroscopy, and NiTi transformation temperatures were determined by differential scanning calorimetry (DSC) before and after the surface treatment. An ion release experiment was carried out up to one month of immersion in SBF for both oxidized and untreated surfaces. The results show that oxidation treatment in a low-oxygen pressure atmosphere leads to a high surface Ti/Ni ratio, a very low Ni surface concentration and a thick oxide layer. This oxidation treatment does not significantly affect the shape memory properties of the alloy. Moreover, the oxide formed significantly decreases Ni release into exterior medium comparing with untreated surfaces. As a consequence, this new oxidation treatment could be of great interest for biomedical applications, as it could minimize sensitization and allergies and improve biocompatibility and corrosion resistance of NiTi shape memory alloys. (c) 2005 Wiley Periodicals, Inc.

Synthesis and characterization of a biocompatible chitosan-based hydrogel cross-linked via 'click' chemistry for controlled drug release.

PubMed

Guaresti, O; García-Astrain, C; Palomares, T; Alonso-Varona, A; Eceiza, A; Gabilondo, N

2017-09-01

A chemically cross-linked chitosan-based hydrogel was successfully synthesized through Diels-Alder (DA) reaction and characterized. The final product was obtained after different steps; on the one hand, furan-modified chitosan (Cs-Fu) was synthesized by the reaction of furfural with the free amino groups of chitosan. On the other hand, highlighting the novelty of the present research, maleimide-functionalized chitosan (Cs-AMI) was prepared by the reaction of a maleimide-modified aminoacid with the amino groups of chitosan through amide coupling. The two complementary chitosan derivatives were cross-linked to the final hydrogel network. Both modification reactions were confirmed by FTIR and 1 H NMR, obtaining a degree of substitution (DS) of 31% and 26% for Cs-Fu and Cs-AMI, respectively. The as-designed hydrogel was analyzed in terms of microstructure, swelling capacity and rheological behaviour. The hydrogel showed pH-sensitivity, biocompatibility and inhibitory bacterial activity, promising features for biomedical applications, particularly for targeted-drug delivery. Copyright © 2017 Elsevier B.V. All rights reserved.

Caffeine-catalyzed gels.

PubMed

DiCiccio, Angela M; Lee, Young-Ah Lucy; Glettig, Dean L; Walton, Elizabeth S E; de la Serna, Eva L; Montgomery, Veronica A; Grant, Tyler M; Langer, Robert; Traverso, Giovanni

2018-07-01

Covalently cross-linked gels are utilized in a broad range of biomedical applications though their synthesis often compromises easy implementation. Cross-linking reactions commonly utilize catalysts or conditions that can damage biologics and sensitive compounds, producing materials that require extensive post processing to achieve acceptable biocompatibility. As an alternative, we report a batch synthesis platform to produce covalently cross-linked materials appropriate for direct biomedical application enabled by green chemistry and commonly available food grade ingredients. Using caffeine, a mild base, to catalyze anhydrous carboxylate ring-opening of diglycidyl-ether functionalized monomers with citric acid as a tri-functional crosslinking agent we introduce a novel poly(ester-ether) gel synthesis platform. We demonstrate that biocompatible Caffeine Catalyzed Gels (CCGs) exhibit dynamic physical, chemical, and mechanical properties, which can be tailored in shape, surface texture, solvent response, cargo release, shear and tensile strength, among other potential attributes. The demonstrated versatility, low cost and facile synthesis of these CCGs renders them appropriate for a broad range of customized engineering applications including drug delivery constructs, tissue engineering scaffolds, and medical devices. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

Fluorimetric assay of interaction of protein with ferrofluids

NASA Astrophysics Data System (ADS)

Mallik, Dhriti; Mir, Aparna; Bhattacharya, Soumya; Nayar, Suprabha

2011-01-01

Magnetic iron oxide nanoparticles are inherently biocompatible and are amenable to post synthesis surface modification, making them excellent candidates for many important applications. If the above can be achieved in a single-step i.e., in situ synthesis and functionalization, the results are expected to be more dramatic for sensitive detection of biomolecules. For any application, it is necessary to confer a high level of binding specificity through surface chemistry, which can be introduced by using biological moieties that possess lock-and-key interactions, like those observed in antibody-antigen and enzyme-substrate recognition. In this paper, we have synthesized water based ferrofluids with serum albumin, the major protein component of blood. A series of other ferrofluids using different biocompatible polymers have also been studied with respect to their size determined by transmission electron microscopy, magnetic behavior with the aid of vibrating sample magnetometry and binding capability to bovine serum albumin by quenching of its native fluorescence. From our results, it can be inferred that binding has taken place between magnetic particles and biomolecules, the binding constants of which indirectly reveal the efficiency of the interaction.

Biocompatible click chemistry enabled compartment-specific pH measurement inside E. coli

PubMed Central

Yang, Maiyun; Jalloh, Abubakar S.; Wei, Wei

2014-01-01

Bioorthogonal reactions, especially the Cu(I)-catalyzed azide-alkyne cycloaddition, have revolutionized our ability to label and manipulate biomolecules under living conditions. The cytotoxicity of Cu(I) ions, however, has hindered the application of this reaction in the internal space of living cells. By systematically surveying a panel of Cu(I)-stabilizing ligands in promoting protein labeling within the cytoplasm of E. coli, here we identify a highly efficient and biocompatible catalyst for intracellular modification of proteins by azide-alkyne cycloaddition. This reaction permits us to conjugate an environment-sensitive fluorophore site-specifically onto HdeA, an acid-stress chaperone that adopts pH-dependent conformational changes, in both the periplasm and cytoplasm of E. coli. The resulting protein-fluorophore hybrid pH indicators enable compartment-specific pH measurement to determine the pH gradient across the E. coli cytoplasmic membrane. This construct also allows the measurement of E. coli transmembrane potential, and the determination of the proton motive force across its inner membrane under normal and acid-stress conditions. PMID:25236616

Multishell Au/Ag/SiO 2 nanorods with tunable optical properties as single particle orientation and rotational tracking probes

DOE PAGES

Chen, Kuangcai; Lin, Chia -Cheng; Vela, Javier; ...

2015-04-07

In this study, three-layer core–shell plasmonic nanorods (Au/Ag/SiO 2–NRs), consisting of a gold nanorod core, a thin silver shell, and a thin silica layer, were synthesized and used as optical imaging probes under a differential interference contrast microscope for single particle orientation and rotational tracking. The localized surface plasmon resonance modes were enhanced upon the addition of the silver shell, and the anisotropic optical properties of gold nanorods were maintained. The silica coating enables surface functionalization with silane coupling agents and provides enhanced stability and biocompatibility. Taking advantage of the longitudinal LSPR enhancement, the orientation and rotational information of themore » hybrid nanorods on synthetic lipid bilayers and on live cell membranes were obtained with millisecond temporal resolution using a scientific complementary metal-oxide-semiconductor camera. The results demonstrate that the as-synthesized hybrid nanorods are promising imaging probes with improved sensitivity and good biocompatibility for single plasmonic particle tracking experiments in biological systems.« less

Hybrid Mesoporous Silica-Based Drug Carrier Nanostructures with Improved Degradability by Hydroxyapatite.

PubMed

Hao, Xiaohong; Hu, Xixue; Zhang, Cuimiao; Chen, Shizhu; Li, Zhenhua; Yang, Xinjian; Liu, Huifang; Jia, Guang; Liu, Dandan; Ge, Kun; Liang, Xing-Jie; Zhang, Jinchao

2015-10-27

Potential bioaccumulation is one of the biggest limitations for silica nanodrug delivery systems in cancer therapy. In this study, a mesoporous silica nanoparticles/hydroxyapatite (MSNs/HAP) hybrid drug carrier, which enhanced the biodegradability of silica, was developed by a one-step method. The morphology and structure of the nanoparticles were characterized by TEM, DLS, FT-IR, XRD, N2 adsorption-desorption isotherms, and XPS, and the drug loading and release behaviors were tested. TEM and ICP-OES results indicate that the degradability of the nanoparticles has been significantly improved by Ca(2+) escape from the skeleton in an acid environment. The MSNs/HAP sample exhibits a higher drug loading content of about 5 times that of MSNs. The biological experiment results show that the MSNs/HAP not only exhibits good biocompatibility and antitumor effect but also greatly reduces the side effects of free DOX. The as-synthesized hybrid nanoparticles may act as a promising drug delivery system due to their good biocompatibility, high drug loading efficiency, pH sensitivity, and excellent biodegradability.

Use of the Chinese (Taiwan) version of the Social Phobia Inventory (SPIN) among early adolescents in rural areas: reliability and validity study.

PubMed

Tsai, Chia-Fen; Wang, Shuu-Jiun; Juang, Kai-Dih; Fuh, Jong-Ling

2009-08-01

To assess the screening abilities of the Chinese (Taiwan) version of the Social Phobia Inventory (SPIN) for evaluating social phobia in an adolescent community sample. A total of 3,393 students (1,669 boys, 1,724 girls), aged 13-15, completed the SPIN questionnaire. A total of 144 students were enrolled for validity. The Mini-International-Neuropsychiatric-Interview-Kid (MINI-Kid) was used to establish Diagnostic and Statistical Manual of Mental Disorders-IV diagnosis. The mean SPIN total score of all subjects was 14.2 +/- 9.4, which was higher in girls than in boys (14.7 +/- 9.4 vs. 13.7 +/- 9.1; p < 0.01). The 7th graders had the highest SPIN total scores compared with the 8th and 9th graders (15.4 +/- 9.7 vs. 13.4 +/- 9.1 and 14.0 +/- 9.4; p < 0.001). Internal consistency (Cronbach's alpha = 0.85) and test-retest reliability (r = 0.73) were both good. A cut-off score of 25 resulted in balanced sensitivity (80%) and specificity (77%). The Chinese (Taiwan) SPIN has good screening abilities. The cut-offs are different from those in other countries, and highlight the importance of culturally adapted cut-offs.