Integration of a photonic crystal polarization beam splitter and waveguide bend.

PubMed

Zheng, Wanhua; Xing, Mingxin; Ren, Gang; Johnson, Steven G; Zhou, Wenjun; Chen, Wei; Chen, Lianghui

2009-05-11

In this work, we present the design of an integrated photonic-crystal polarization beam splitter (PC-PBS) and a low-loss photonic-crystal 60 degrees waveguide bend. Firstly, the modal properties of the PC-PBS and the mechanism of the low-loss waveguide bend are investigated by the two-dimensional finite-difference time-domain (FDTD) method, and then the integration of the two devices is studied. It shows that, although the individual devices perform well separately, the performance of the integrated circuit is poor due to the multi-mode property of the PC-PBS. By introducing deformed airhole structures, a single-mode PC-PBS is proposed, which significantly enhance the performance of the circuit with the extinction ratios remaining above 20 dB for both transverse-electric (TE) and transverse-magnetic (TM) polarizations. Both the specific result and the general idea of integration design are promising in the photonic crystal integrated circuits in the future.

Silicon on-chip bandpass filters for the multiplexing of high sensitivity photonic crystal microcavity biosensors

PubMed Central

Chakravarty, Swapnajit; Yang, Chun-Ju; Wang, Zheng; Tang, Naimei; Fan, Donglei; Chen, Ray T.

2015-01-01

A method for the dense integration of high sensitivity photonic crystal (PC) waveguide based biosensors is proposed and experimentally demonstrated on a silicon platform. By connecting an additional PC waveguide filter to a PC microcavity sensor in series, a transmission passband is created, containing the resonances of the PC microcavity for sensing purpose. With proper engineering of the passband, multiple high sensitivity PC microcavity sensors can be integrated into microarrays and be interrogated simultaneously between a single input and a single output port. The concept was demonstrated with a 2-channel L55 PC biosensor array containing PC waveguide filters. The experiment showed that the sensors on both channels can be monitored simultaneously from a single output spectrum. Less than 3 dB extra loss for the additional PC waveguide filter is observed. PMID:25829549

Acoustic scattering from phononic crystals with complex geometry.

PubMed

Kulpe, Jason A; Sabra, Karim G; Leamy, Michael J

2016-05-01

This work introduces a formalism for computing external acoustic scattering from phononic crystals (PCs) with arbitrary exterior shape using a Bloch wave expansion technique coupled with the Helmholtz-Kirchhoff integral (HKI). Similar to a Kirchhoff approximation, a geometrically complex PC's surface is broken into a set of facets in which the scattering from each facet is calculated as if it was a semi-infinite plane interface in the short wavelength limit. When excited by incident radiation, these facets introduce wave modes into the interior of the PC. Incorporation of these modes in the HKI, summed over all facets, then determines the externally scattered acoustic field. In particular, for frequencies in a complete bandgap (the usual operating frequency regime of many PC-based devices and the requisite operating regime of the presented theory), no need exists to solve for internal reflections from oppositely facing edges and, thus, the total scattered field can be computed without the need to consider internal multiple scattering. Several numerical examples are provided to verify the presented approach. Both harmonic and transient results are considered for spherical and bean-shaped PCs, each containing over 100 000 inclusions. This facet formalism is validated by comparison to an existing self-consistent scattering technique.

Thermal, dielectric and barocaloric properties of NH4HSO4 crystallized from an aqueous solution and the melt

NASA Astrophysics Data System (ADS)

Mikhaleva, E. A.; Flerov, I. N.; Kartashev, A. V.; Gorev, M. V.; Bogdanov, E. V.; Bondarev, V. S.

2017-05-01

A study of heat capacity, thermal dilatation, permittivity, dielectric loops and susceptibility to hydrostatic pressure was carried out on quasi-ceramic samples of NH4HSO4 obtained from an aqueous solution as well as the melt. The main parameters of the successive P21/c (T1) ↔ Pc (T2) ↔ P1 phase transitions did not depend on the method of preparation of the samples, and were close to those determined in previous studies of single crystal and powder, except for the sign and magnitude of the baric coefficient for T2. Direct measurements of the pressure effect on the permittivity and thermal properties showed dT2/dp = -123 K·GPa-1, which is consistent in terms of magnitude and sign with the baric coefficient evaluated using dilatometric and calorimetric data in the framework of the Clausius-Clapeyron equation. Thus, the temperature region of the ferroelectric Pc phase existence is extended under pressure. A strong decrease in the entropy jump at the Pc ↔ P1 transformation with an increase in pressure, and the linear dependence of T2 on pressure, indicate that an increase in pressure shifts this phase transition towards the tricritical point on the T-p phase diagram. A significant barocaloric effect was found in the region of the Pc ↔ P1 phase transition.

Silicon on-chip bandpass filters for the multiplexing of high sensitivity photonic crystal microcavity biosensors

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

Yan, Hai, E-mail: hai.yan@utexas.edu; Zou, Yi; Yang, Chun-Ju

A method for the dense integration of high sensitivity photonic crystal (PC) waveguide based biosensors is proposed and experimentally demonstrated on a silicon platform. By connecting an additional PC waveguide filter to a PC microcavity sensor in series, a transmission passband is created, containing the resonances of the PC microcavity for sensing purpose. With proper engineering of the passband, multiple high sensitivity PC microcavity sensors can be integrated into microarrays and be interrogated simultaneously between a single input and a single output port. The concept was demonstrated with a 2-channel L55 PC biosensor array containing PC waveguide filters. The experimentmore » showed that the sensors on both channels can be monitored simultaneously from a single output spectrum. Less than 3 dB extra loss for the additional PC waveguide filter is observed.« less

The role of biotin and oxamate in the carboxyl transferase reaction of pyruvate carboxylase

PubMed Central

Lietzan, Adam D.; Lin, Yi; St. Maurice, Martin

2014-01-01

Pyruvate carboxylase (PC) is a biotin-dependent enzyme that catalyzes the MgATP-dependent carboxylation of pyruvate to oxaloacetate, an important anaplerotic reaction in central metabolism. During catalysis, carboxybiotin is translocated to the carboxyltransferase domain where the carboxyl group is transferred to the acceptor substrate, pyruvate. Many studies on the carboxyltransferase domain of PC have demonstrated an enhanced oxaloacetate decarboxylation activity in the presence of oxamate and it has been shown that oxamate accepts a carboxyl group from carboxybiotin during oxaloacetate decarboxylation. The X-ray crystal structure of the carboxyltransferase domain from Rhizobium etli PC reveals that oxamate is positioned in the active site in an identical manner to the substrate, pyruvate, and kinetic data are consistent with the oxamate-stimulated decarboxylation of oxaloacetate proceeding through a simple ping-pong bi bi mechanism in the absence of the biotin carboxylase domain. Additionally, analysis of truncated PC enzymes indicates that the BCCP domain devoid of biotin does not contribute directly to the enzymatic reaction and conclusively demonstrates a biotin-independent oxaloacetate decarboxylation activity in PC. These findings advance the description of catalysis in PC and can be extended to the study of related biotin-dependent enzymes. PMID:25157442

Novel in-situ nanocomposites of phthalonitrile end-capped polyarylene ether nitrile/copper phthalocyanine

NASA Astrophysics Data System (ADS)

Tong, Lifen; Wei, Renbo; Liu, Xiaobo

2017-01-01

A novel phthalonitrile end-capped polyarylene ether nitrile (PEN-Ph)/copper phthalocyanine (CuPc) nanocomposites which possesses crosslinking reaction combined with crystallization behaviour were prepared successfully through in-situ reaction and hot-compression. In the presence of copper ion, CuPc were formed through crosslinking reaction among the phthalonitrile at the end of the PEN-Ph main chain and 1, 3, 5-Tri-(3, 4-dicyanophenoxy) benzene (TPh). Besides, the formed CuPc can play the role of nucleating agent to improve the crystallinity of the polymers. The influence of the crosslinking reaction and crystallization behaviour were investigated. The results show that the crystallization and crosslinking coexist in the system at the same time. Scanning electron microscope (SEM) images show that the crystals of the PEN-Ph grow after the hot-compressing procedure. Moreover, the glass transition temperature (Tg) increases while the crystallinity declines slightly with the low amount of copper ions. The increase of Tg is mainly caused by the crosslinking reaction, indicating that the copper can be used as a crosslinking agent in this system. Due to formation of the CuPc and the crystallization behaviour, the dielectric constant increased as expected from 3.2 to 4.9 while the dielectric loss decreased. Therefore, the PEN-Ph/CuPc in-situ nanocomposites will have a good prospect for application in electronic field.

Performance analysis of all-optical XOR gate with photonic crystal semiconductor optical amplifier-assisted Mach-Zehnder interferometer at 160 Gb/s

NASA Astrophysics Data System (ADS)

Kotb, Amer; Zoiros, Kyriakos E.

2017-11-01

The photonic crystal (PC) can be used to prohibit, confine, or control the propagation of light in a photonic band-gap. The performance of an ultrafast exclusive disjunction (XOR) gate-implemented with a photonic crystal semiconductor optical amplifier (PC-SOA)-assisted Mach-Zehnder interferometer (MZI) is numerically investigated and analyzed at a data rate of 160 Gb/s. The impact of the data signals and PC-SOA's critical parameters on the output quality factor (Q-factor) is examined and assessed. The simulation results demonstrate that the XOR gate which is based on the proposed scheme is capable of operating at the target data rate with logical correctness and high quality. This is achieved with better performance than when having conventional SOAs in the MZI, which justifies employing PC-SOAs as nonlinear elements.

Transmission property of the one-dimensional phononic crystal thin plate by the eigenmode matching theory

NASA Astrophysics Data System (ADS)

Hou, Zhilin; Assouar, Badreddine M.

2008-05-01

Eigenmode matching theory, which was developed originally for the band structure and the transmission property of the infinite phononic crystal (PC), is extended to deal with the PC thin plate. By this method, the transmission property of the one-dimensional PC thin plate with and without a uniform substrate is investigated. It is shown that in the PC thin plate without a substrate, the permitted band of the structure can be separated into two parts, which can be excited by the incident antisymmetric and symmetric Lamb modes, respectively. However, for the PC plate with a substrate, the energy conversion between the symmetric and antisymmetric modes can be found in the transmission spectrum. The physical origin of such an energy conversion is discussed.

Enhancement of second harmonic generation in NaNO{sub 2}-infiltrated opal photonic crystal using structural light focusing

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

Zaytsev, Kirill I., E-mail: kirzay@gmail.com; Yurchenko, Stanislav O., E-mail: st.yurchenko@mail.ru

Experimental and numerical results for second harmonic generation (SHG) in photonic crystal (PC) based on NaNO{sub 2}-infiltrated opal matrix are presented. SHG is performed in reflection mode; thus, the direction of the SHG maximum is equal to the angle of mirror reflection. The PC was pumped with femtosecond optical pulses at different angles of incidence, allowing the dependence of the SHG efficiency on the location of the fundamental wavelength toward the PC band gap (BG) to be examined. The most efficient SHG was observed when pumping the BG of the PC. To interpret the experimental results, finite-difference time-domain numerical simulationsmore » of the light interaction with the PC were conducted. The observed effect of highly efficient SHG is associated with structural light focusing, and, as a consequence, with strong optical field localization within certain near-surface PC regions. Thus, SHG enhancement based on structural light focusing in PC was demonstrated.« less

Thermal characterization and analysis of phase change random access memory

NASA Astrophysics Data System (ADS)

Giraud, V.; Cluzel, J.; Sousa, V.; Jacquot, A.; Dauscher, A.; Lenoir, B.; Scherrer, H.; Romer, S.

2005-07-01

The cross-plane thermal conductivity of Ge2Sb2Te5, either in its amorphous state or fcc crystallized state, and titanium nitride (TiN) thin films has been measured at room temperature by the 3ω method. These materials are involved in the fabrication of phase change random access memory (PC-RAM), Ge2Sb2Te5 and TiN being the PC and pseudoelectrode materials, respectively. The thermal conductivity of insulating SiO2 and ZnS :SiO2 layers was determined too. Each thermal conductivity measurement was performed by the means of at least two strip widths in order to check both the measurement self-consistency and the measurement accuracy. The performance of PC-RAM cells, i.e., the time needed to reach the melting temperature of the PC material and the cooling speed, has been evaluated as a function of both the measured thermal conductivity of the PC material and the reset current intensity independently of the thermal properties of the pseudoelectrodes by the way of analytical formula. The influence of the thickness and the thermal properties of the pseudoelectrodes on the performances have been determined by numerical simulations.

Polarized micro-cavity organic light-emitting devices.

PubMed

Park, Byoungchoo; Kim, Mina; Park, Chan Hyuk

2009-04-27

We present the results of a study of light emissions from a polarized micro-cavity Organic Light-Emitting Device (OLED), which consisted of a flexible, anisotropic one-dimensional (1-D) photonic crystal (PC) film substrate. It is shown that luminous Electroluminescent (EL) emissions from the polarized micro-cavity OLED were produced at relatively low operating voltages. It was also found that the peak wavelengths of the emitted EL light corresponded to the two split eigen modes of the high-energy band edges of the anisotropic PC film, with a strong dependence on the polarization state of the emitting light. For polarization along the ordinary axis of the anisotropic PC film, the optical split micro-cavity modes occurred at the longer high-energy photonic band gap (PBG) edge, while for polarization along the extraordinary axis, the split micro-cavity modes occurred at the shorter high-energy PBG edge, with narrow bandwidths. We demonstrated that the polarization and emission mode of the micro-cavity OLED may be selected by choosing the appropriate optical axis of the anisotropic 1-D PC film.

Thermally Driven Photonic Actuator Based on Silica Opal Photonic Crystal with Liquid Crystal Elastomer.

PubMed

Xing, Huihui; Li, Jun; Shi, Yang; Guo, Jinbao; Wei, Jie

2016-04-13

We have developed a novel thermoresponsive photonic actuator based on three-dimensional SiO2 opal photonic crystals (PCs) together with liquid crystal elastomers (LCEs). In the process of fabrication of such a photonic actuator, the LCE precursor is infiltrated into the SiO2 opal PC followed by UV light-induced photopolymerization, thereby forming the SiO2 opal PC/LCE composite film with a bilayer structure. We find that this bilayer composite film simultaneously exhibits actuation behavior as well as the photonic band gap (PBG) response to external temperature variation. When the SiO2 opal PC/LCE composite film is heated, it exhibits a considerable bending deformation, and its PBG shifts to a shorter wavelength at the same time. In addition, this actuation is quite fast, reversible, and highly repeatable. The thermoresponsive behavior of the SiO2 opal PC/LCE composite films mainly derives from the thermal-driven change of nematic order of the LCE layer which leads to the asymmetric shrinkage/expansion of the bilayer structure. These results will be of interest in designing optical actuator systems for environment-temperature detection.

Ab Initio Crystal Field for Lanthanides.

PubMed

Ungur, Liviu; Chibotaru, Liviu F

2017-03-13

An ab initio methodology for the first-principle derivation of crystal-field (CF) parameters for lanthanides is described. The methodology is applied to the analysis of CF parameters in [Tb(Pc) 2 ] - (Pc=phthalocyanine) and Dy 4 K 2 ([Dy 4 K 2 O(OtBu) 12 ]) complexes, and compared with often used approximate and model descriptions. It is found that the application of geometry symmetrization, and the use of electrostatic point-charge and phenomenological CF models, lead to unacceptably large deviations from predictions based on ab initio calculations for experimental geometry. It is shown how the predictions of standard CASSCF (Complete Active Space Self-Consistent Field) calculations (with 4f orbitals in the active space) can be systematically improved by including effects of dynamical electronic correlation (CASPT2 step) and by admixing electronic configurations of the 5d shell. This is exemplified for the well-studied Er-trensal complex (H 3 trensal=2,2',2"-tris(salicylideneimido)trimethylamine). The electrostatic contributions to CF parameters in this complex, calculated with true charge distributions in the ligands, yield less than half of the total CF splitting, thus pointing to the dominant role of covalent effects. This analysis allows the conclusion that ab initio crystal field is an essential tool for the decent description of lanthanides. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Influence of the morphology of the copper(II) phthalocyanine thin film on the performance of organic field-effect transistors

NASA Astrophysics Data System (ADS)

Xu, Jing; Liu, Xueqiang; Wang, Hailong; Hou, Wenlong; Zhao, Lele; Zhang, Haiquan

2017-01-01

Organic thin-film transistors (OTFTs) with high crystallization copper phthalocyanine (CuPc) active layers were fabricated. The performance of CuPc OTFTs was studied without and with treatment by Solvent Vapor Annealing on CuPc film. The values of the threshold voltage without and with solvent-vapor annealing are -17 V and -10.5 V respectively. The field-effect mobility values in saturation region of CuPc thin-film transistors without and with Solvent Vapor Annealing are 0.00027 cm2/V s and 0.0025 cm2/V s respectively. Meanwhile, the high crystallization of the CuPc film with a larger grain size and less grain boundaries can be observed by investigating the morphology of the CuPc active layer through scanning electron microscopy and X-ray diffraction. The experimental results showed the decreased of the resistance of the conducting channel, that led to a performance improvement of the OTFTs.

Crystal Structures of Human and Staphylococcus aureus Pyruvate Carboxylase and Molecular Insights into the Carboxyltransfer Reaction

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

Xiang,S.; Tong, L.

2008-01-01

Pyruvate carboxylase (PC) catalyzes the biotin-dependent production of oxaloacetate and has important roles in gluconeogenesis, lipogenesis, insulin secretion and other cellular processes. PC contains the biotin carboxylase (BC), carboxyltransferase (CT) and biotin-carboxyl carrier protein (BCCP) domains. We report here the crystal structures at 2.8-Angstroms resolution of full-length PC from Staphylococcus aureus and the C-terminal region (missing only the BC domain) of human PC. A conserved tetrameric association is observed for both enzymes, and our structural and mutagenesis studies reveal a previously uncharacterized domain, the PC tetramerization (PT) domain, which is important for oligomerization. A BCCP domain is located in themore » active site of the CT domain, providing the first molecular insights into how biotin participates in the carboxyltransfer reaction. There are dramatic differences in domain positions in the monomer and the organization of the tetramer between these enzymes and the PC from Rhizobium etli.« less

Enhanced performance of photonic crystal GaN light-emitting diodes with graphene transparent electrodes

NASA Astrophysics Data System (ADS)

Ge, Hai-Liang; Xu, Chen; Xu, Kun; Xun, Meng; Wang, Jun; Liu, Jie

2015-03-01

The two-dimensional (2D) triangle lattice air hole photonic crystal (PC) GaN-based light-emitting diodes (LED) with double-layer graphene transparent electrodes (DGTE) have been produced. The current spreading effect of the double-layer graphene (GR) on the surface of the PC structure of the LED has been researched. Specially, we found that the part of the graphene suspending over the air hole of the PC structure was of much higher conductivity, which reduced the average sheet resistance of the graphene transparent conducting electrode and improved the current spreading of the PC LED. Therefore, the work voltage of the DGTE-PC LED was obviously decreased, and the output power was greatly enhanced. The COMSOL software was used to simulate the current density distribution of the samples. The results show that the etching of PC structure results in the degradation of the current spreading and that the graphene transparent conducting electrode can offer an uniform current spreading in the DGTE-PC LED. PACS: 85.60.Jb; 68.65.Pq; 42.70.Qs

Ultrasensitive Sensing Material Based on Opal Photonic Crystal for Label-Free Monitoring of Transferrin.

PubMed

Wu, Enqi; Peng, Yuan; Zhang, Xihao; Bai, Jialei; Song, Yanqiu; He, Houluo; Fan, Longxing; Qu, Xiaochen; Gao, Zhixian; Liu, Ying; Ning, Baoan

2017-02-22

A new opal photonic crystal (PC) sensing material, allowing label-free detection of transferrin (TRF), is proposed in the current study. This photonic crystal was prepared via a vertical convective self-assembly method with monodisperse microspheres polymerized by methyl methacrylate (MMA) and 3-acrylamidophenylboronic acid (AAPBA). FTIR, TG, and DLS were used to characterize the components and particle size of the monodisperse microspheres. SEM was used to observe the morphology of the PC. The diffraction peak intensity decreases as the TRF concentration increase. This was due to the combination of TRF to the boronic acid group of the photonic crystal. After condition optimization, a standard curve was obtained and the linear range of TRF concentration was from 2 × 10 -3 ng/mL to 200 ng/mL. Measurement of TRF concentration in simulated urine sample was also investigated using the sensing material. The results indicated that the PC provided a cheap, label-free, and easy-to-use alternative for TRF determination in clinical diagnostics.

Crystal Structure of Crataeva tapia Bark Protein (CrataBL) and Its Effect in Human Prostate Cancer Cell Lines

PubMed Central

Ferreira, Joana Gasperazzo; Silva, Mariana Cristina Cabral; Silva-Lucca, Rosemeire Aparecida; Mentele, Reinhard; Paredes-Gamero, Edgar Julian; Bertolin, Thiago Carlos; dos Santos Correia, Maria Tereza; Paiva, Patrícia Maria Guedes; Gustchina, Alla; Wlodawer, Alexander; Oliva, Maria Luiza Vilela

2013-01-01

A protein isolated from the bark of Crataeva tapia (CrataBL) is both a Kunitz-type plant protease inhibitor and a lectin. We have determined the amino acid sequence and three-dimensional structure of CrataBL, as well as characterized its selected biochemical and biological properties. We found two different isoforms of CrataBL isolated from the original source, differing in positions 31 (Pro/Leu); 92 (Ser/Leu); 93 (Ile/Thr); 95 (Arg/Gly) and 97 (Leu/Ser). CrataBL showed relatively weak inhibitory activity against trypsin (Kiapp = 43 µM) and was more potent against Factor Xa (Kiapp = 8.6 µM), but was not active against a number of other proteases. We have confirmed that CrataBL contains two glycosylation sites and forms a dimer at high concentration. The high-resolution crystal structures of two different crystal forms of isoform II verified the β-trefoil fold of CrataBL and have shown the presence of dimers consisting of two almost identical molecules making extensive contacts (∼645 Å2). The structure differs from those of the most closely related proteins by the lack of the N-terminal β-hairpin. In experiments aimed at investigating the biological properties of CrataBL, we have shown that addition of 40 µM of the protein for 48 h caused maximum growth inhibition in MTT assay (47% of DU145 cells and 43% of PC3 cells). The apoptosis of DU145 and PC3 cell lines was confirmed by flow cytometry using Annexin V/FITC and propidium iodide staining. Treatment with CrataBL resulted in the release of mitochondrial cytochrome c and in the activation of caspase-3 in DU145 and PC3 cells. PMID:23823708

Coupling of free space sub-terahertz waves into dielectric slabs using PC waveguides.

PubMed

Ghattan, Z; Hasek, T; Shahabadi, M; Koch, M

2008-04-28

The paper presents theoretical and experimental results on photonic crystal structures which work under the self-collimation condition to couple free space waves into dielectric slabs in the sub-terahertz range. Using a standard machining process, two-dimensional photonic crystal structures consisting of a square array of air holes in the dielectric medium are fabricated. One of the structures has two adjacent parallel line-defects that improve the coupling efficiency. This leads to a combination of self-collimation and directional emission of electromagnetic waves. The experimental results are in good agreement with those of the Finite- Element-Method calculations. Experimentally we achieve a coupling efficiency of 63%.

Microcontact imprinted quartz crystal microbalance nanosensor for protein C recognition.

PubMed

Bakhshpour, Monireh; Özgür, Erdoğan; Bereli, Nilay; Denizli, Adil

2017-03-01

Detection of protein C (PC) in human serum was performed by quartz crystal microbalance (QCM) based on molecular imprinting technique (MIP). The high-resolution and mass-sensitive QCM based sensor was integrated with high sensitivity and selectivity of the MIP technique. The PC microcontact imprinted (PC-μCIP) nanofilm was prepared on the glass surface. Then, the PC-μCIP/QCM sensor was prepared with 2-hydroxyethyl methacrylate (HEMA), ethylene glycol dimethacrylate (EGDMA) and N-methacryloyl l-histidine methylester (MAH) as the functional monomer with copper(II) ions. The polymerization was performed under UV light (100W and 365nm) for 20-25min under nitrogen atmosphere. The characterization studies of QCM sensor were done by observation using atomic force microscopy (AFM), contact angle measurements, ellipsometry and fourier transform infrared spectroscopy (FTIR). Detection of PC was investigated in a concentration range of 0.1-30μg/mL. Selectivity of PC-μCIP and PC non-imprinted/QCM (PC-non-μCIP) sensors for PC determination was investigated by using proteins namely hemoglobin (Hb), human serum albumin (HSA) and fibrinogen solutions. QCM sensor was also used for detection of PC molecules in aqueous solutions and human plasma. The detection limit was determined as 0.01μg/mL for PC analysis. The PC-μCIP/QCM sensor was used for five consecutive adsorption-desorption cycles. According to the results, the PC-μCIP/QCM sensor had obtained high selectivity and sensitivity for detection of PC molecules. Copyright © 2016 Elsevier B.V. All rights reserved.

Photonic crystal materials and their application in biomedicine.

PubMed

Chen, Huadong; Lou, Rong; Chen, Yanxiao; Chen, Lili; Lu, Jingya; Dong, Qianqian

2017-11-01

Photonic crystal (PC) materials exhibit unique structural colors that originate from their intrinsic photonic band gap. Because of their highly ordered structure and distinct optical characteristics, PC-based biomaterials have advantages in the multiplex detection, biomolecular screening and real-time monitoring of biomolecules. In addition, PCs provide good platforms for drug loading and biomolecule modification, which could be applied to biosensors and biological carriers. A number of methods are now available to fabricate PC materials with variable structure colors, which could be applied in biomedicine. Emphasis is given to the description of various applications of PC materials in biomedicine, including drug delivery, biodetection and tumor screening. We believe that this article will promote greater communication among researchers in the fields of chemistry, material science, biology, medicine and pharmacy.

Multi/demulti-plexer based on transverse mode conversion in photonic crystal waveguides.

PubMed

Zhou, Wen; Zhuang, Yuyang; Ji, Ke; Chen, He-ming

2015-09-21

A novel mode multiplexer and demultiplexer (MMUX/DEMMUX) based on 2-D photonic crystal (PC) at 1550 nm is proposed. The PC-based mode MMUX/DEMMUX including mode conversion function with a single-mode and multi-mode waveguides can be realized by quasi phase-matching TE(0) & TE(1) modes of two waveguides. 2DFinite-Difference-Time-Domain and beam propagation methods are used for simulation. The results show that PC-based mode MMUX/DEMMUX has the potential for high-capacity MDM optical communication systems with a low insertion loss (<0.36dB), low mode crosstalk (< -20.9 dB) and wide bandwidth (~100 nm).

Enhanced emission of quantum dots embedded within the high-index dielectric regions of photonic crystal slabs

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

See, Gloria G.; Naughton, Matt S.; Kenis, Paul J. A.

2016-04-25

We demonstrate a method for combining sputtered TiO{sub 2} deposition with liquid phase dip-coating of a quantum dot (QD) layer that enables precise depth placement of QD emitters within a high-index dielectric film, using a photonic crystal (PC) slab resonator to demonstrate enhanced emission from the QDs when they are located at a specific depth within the film. The depth of the QDs within the PC is found to modulate the resonant wavelength of the PC as well as the emission enhancement efficiency, as the semiconducting material embedded within the dielectric changes its spatial overlap with the resonant mode.

Optimization of experimental conditions for the monitoring of nucleation and growth of racemic Diprophylline from the supercooled melt

NASA Astrophysics Data System (ADS)

Lemercier, Aurélien; Viel, Quentin; Brandel, Clément; Cartigny, Yohann; Dargent, Eric; Petit, Samuel; Coquerel, Gérard

2017-08-01

Since more and more pharmaceutical substances are developed as amorphous forms, it is nowadays of major relevance to get insights into the nucleation and growth mechanisms from supercooled melts (SCM). A step-by-step approach of recrystallization from a SCM is presented here, designed to elucidate the impact of various experimental parameters. Using the bronchodilator agent Diprophylline (DPL) as a model compound, it is shown that optimal conditions for informative observations of the crystallization behaviour from supercooled racemic DPL require to place samples between two cover slides with a maximum sample thickness of 20 μm, and to monitor recrystallization during an annealing step of 30 min at 70 °C, i.e. about 33 °C above the temperature of glass transition. In these optimized conditions, it could be established that DPL crystallization proceeds in two steps: spontaneous nucleation and growth of large and well-faceted particles of a new crystal form (primary crystals: PC) and subsequent crystallization of a previously known form (RII) that develops from specific surfaces of PC. The formation of PC particles therefore constitutes the key-step of the crystallization events and is shown to be favoured by at least 2.33 wt% of the major chemical impurity, Theophylline.

Morphology-defined interaction of copper phthalocyanine with O 2/H 2O

DOE PAGES

Muckley, Eric S.; Miller, Nicholas; Jacobs, Christopher B.; ...

2016-11-01

Copper phthalocyanine (CuPc) is an important hole transport layer for organic photovoltaics (OPVs), but its interaction with ambient gas/vapor may lead to changes in electronic properties of the material which subsequently limits the lifetime of OPV devices. CuPc films of thickness 25 nm and 100 nm were grown by thermal sublimation at 25°C, 150°C, and 250°C in order to vary morphology. Using a source-measure unit and a quartz crystal microbalance (QCM), we measured changes in electrical resistance and film mass in situ during exposure to controlled pulses of O 2 and H 2O vapor. Mass loading by O 2 wasmore » enhanced by a factor of 5 in films deposited at 250 C, possibly due to the ~200° C CuPc -> transition which allows higher O 2 mobility between stacked molecules. While gas/vapor sorption occurred over timescales of < 10 minutes, resistance change occurred over timescales > 1 hour, suggesting that mass change occurs by rapid adsorption at active surface sites, whereas resistive response is dominated by slow diffusion of adsorbates into the film bulk. Resistive response generally increases with film deposition temperature due to increased porosity associated with larger crystalline domains. The 25 nm thick films exhibit higher resistive response than 100 nm thick films after an hour of O 2/H 2O exposure due to the smaller analyte diffusion length required for reaching the film/electrode interface. We found evidence of decoupling of CuPc from the gold-coated QCM crystal due to preferential adsorption of O 2/H 2O molecules on gold, which is consistent with findings of other studies.« less

Photonic crystal active and passive device components in III-V semiconductors

NASA Astrophysics Data System (ADS)

Sabarinathan, Jayshri

Photonic crystals (PC's) are emerging as potentially important candidates in propelling the development in planar photonic integrated circuits, high capacity optical fibers and nanoscopic lasers. Photonic crystals are expected to play a role analogous to that played by crystalline semiconductors in the development of electronic circuits. What makes these photonic crystals more interesting is that introducing "defects"---a missing period or phase slip, in the PC lattice introduces defect modes that lie within the bandgap of the PC. In this investigation, both two dimensional and three dimensional photonic crystals have been fabricated and studied using III-V compound semiconductors which are presently the most useful material systems for integrating with existing optoelectronic technology. A novel single step epitaxial technique to fabricate GaAs-based 3D photonic crystals with sub-micron feature size has been developed employing MBE growth on patterned substrates, ebeam and optical lithography, and lateral wet oxidation of AlGaAs. Transmission characteristics of the fabricated 3D PCs have been measured revealing a 10dB stopband centered at 1 mum for the smallest feature sizes. Electrically injected 2D photonic crystal defect microcavities were designed and fabricated to realize low threshold vertically emitting light sources. The electroluminescent devices were fabricated with GaAs- and InP-based quantum wells heterostructures with emission wavelengths at 0.94mum and 1.55 mum respectively. The light-current, spectral, near- and far-field characteristics of these devices have been studied in detail. The processing and high-aspect ratio etch techniques were carefully developed to create the 2D PCs embedded in the electrically injected apertures. Quantum dots with emission wavelength of 1.04 mum were incorporated into electrically injected 2D PC microcavities to study the electrical and optical confinement simultaneously provided in this configuration. Weak microcavity effects were observed in the fabricated devices. Passive 2D PC's with linear defects, which act as efficient waveguides to confine and channel light even around very sharp bends, have also been investigated. A novel microfluidic sensor using 2D GaAs-based photonic crystal waveguides to detect one or more fluids on the basis of their refractive index properties have been designed, fabricated and demonstrated for the first time.

Effect of film morphology on oxygen and water interaction with copper phthalocyanine

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

Miller, Nicholas; Gredig, Thomas; Ivanov, Ilia N

2016-01-01

Copper phthalocyanine (CuPc) films of thickness 25 nm and 100 nm were grown by thermal sublimation at 25 C, 150 C, and 250 C in order to vary morphology. Using a source-measure unit and a quartz crystal microbalance (QCM), we measured changes in electrical resistance and film mass in situ during exposure to controlled pulses of O2 and H2O vapor. Mass loading by O2 was enhanced by a factor of 5 in films deposited at 250 C, possibly due to the ~200 C CuPc transition which allows higher O2 mobility between stacked molecules. While gas/vapor sorption occurred over timescales ofmore » < 10 minutes, resistance change occurred over timescales > 1 hour, suggesting that mass change occurs by rapid adsorption at active surface sites, whereas resistive response is dominated by slow diffusion of adsorbates into the film bulk. Resistive response generally increases with film deposition temperature due to increased porosity associated with larger crystalline domains. The 25 nm thick films exhibit higher resistive response than 100 nm thick films after an hour of O2/H2O exposure due to the smaller analyte diffusion length required for reaching the film/electrode interface. We found evidence of decoupling of CuPc from the gold-coated QCM crystal due to preferential adsorption of O2/H2O molecules on gold, which is consistent with findings of other studies.« less

Effect of film morphology on oxygen and water interaction with copper phthalocyanine

NASA Astrophysics Data System (ADS)

Muckley, Eric S.; Miller, Nicholas; Gredig, Thomas; Ivanov, Ilia N.

2016-09-01

Copper phthalocyanine (CuPc) films of thickness 25 nm and 100 nm were grown by thermal sublimation at 25°C, 150°C, and 250°C in order to vary morphology. Using a source-measure unit and a quartz crystal microbalance (QCM), we measured changes in electrical resistance and film mass in situ during exposure to controlled pulses of O2 and H2O vapor. Mass loading by O2 was enhanced by a factor of 5 in films deposited at 250°C, possibly due to the 200°C CuPc α->β transition which allows higher O2 mobility between stacked molecules. While gas/vapor sorption occurred over timescales of < 10 minutes, resistance change occurred over timescales < 1 hour, suggesting that mass change occurs by rapid adsorption at active surface sites, whereas resistive response is dominated by slow diffusion of adsorbates into the film bulk. Resistive response generally increases with film deposition temperature due to increased porosity associated with larger crystalline domains. The 25 nm thick films exhibit higher resistive response than 100 nm thick films after an hour of O2/H2O exposure due to the smaller analyte diffusion length required for reaching the film/electrode interface. We found evidence of decoupling of CuPc from the gold-coated QCM crystal due to preferential adsorption of O2/H2O molecules on gold, which is consistent with findings of other studies.

Ultra-directional source of longitudinal acoustic waves based on a two-dimensional solid/solid phononic crystal

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

Morvan, B.; Tinel, A.; Sainidou, R.

2014-12-07

Phononic crystals (PC) can be used to control the dispersion properties of acoustic waves, which are essential to direct their propagation. We use a PC-based two-dimensional solid/solid composite to demonstrate experimentally and theoretically the spatial filtering of a monochromatic non-directional wave source and its emission in a surrounding water medium as an ultra-directional beam with narrow angular distribution. The phenomenon relies on square-shaped equifrequency contours (EFC) enabling self-collimation of acoustic waves within the phononic crystal. Additionally, the angular width of collimated beams is controlled via the EFC size-shrinking when increasing frequency.

Photonic crystal ring resonator-based four-channel dense wavelength division multiplexing demultiplexer on silicon on insulator platform: design and analysis

NASA Astrophysics Data System (ADS)

Sreenivasulu, Tupakula; Bhowmick, Kaustav; Samad, Shafeek A.; Yadunath, Thamerassery Illam R.; Badrinarayana, Tarimala; Hegde, Gopalkrishna; Srinivas, Talabattula

2018-04-01

A micro/nanofabrication feasible compact photonic crystal (PC) ring-resonator-based channel drop filter has been designed and analyzed for operation in C and L bands of communication window. The four-channel demultiplexer consists of ring resonators of holes in two-dimensional PC slab. The proposed assembly design of dense wavelength division multiplexing setup is shown to achieve optimal quality factor, without altering the lattice parameters or resonator size or inclusion of scattering holes. Transmission characteristics are analyzed using the three-dimensional finite-difference time-domain simulation approach. The radiation loss of the ring resonator was minimized by forced cancelation of radiation fields by fine-tuning the air holes inside the ring resonator. An average cross talk of -34 dB has been achieved between the adjacent channels maintaining an average quality factor of 5000. Demultiplexing is achieved by engineering only the air holes inside the ring, which makes it a simple and tolerant design from the fabrication perspective. Also, the device footprint of 500 μm2 on silicon on insulator platform makes it easy to fabricate the device using e-beam lithography technique.

Higher-order mode photonic crystal based nanofluidic sensor

NASA Astrophysics Data System (ADS)

Peng, Wang; Chen, Youping; Ai, Wu

2017-01-01

A higher-order photonic crystal (PC) based nanofluidic sensor, which worked at 532 nm, was designed and demonstrated. A systematical and detailed method for sculpturing a PC sensor for a given peak wavelength value (PWV) and specified materials was illuminated. It was the first time that the higher order mode was used to design PC based nanofluidic sensor, and the refractive index (RI) sensitivity of this sensor had been verified with FDTD simulation software from Lumerical. The enhanced electrical field of higher order mode structure was mostly confined in the channel area, where the enhance field is wholly interacting with the analytes in the channels. The comparison of RI sensitivity between fundamental mode and higher order mode shows the RI variation of higher order mode is 124.5 nm/RIU which is much larger than the fundamental mode. The proposed PC based nanofluidic structure pioneering a novel style for future optofluidic design.

Two-dimensional photonic crystal arrays for polymer:fullerene solar cells.

PubMed

Nam, Sungho; Han, Jiyoung; Do, Young Rag; Kim, Hwajeong; Yim, Sanggyu; Kim, Youngkyoo

2011-11-18

We report the application of two-dimensional (2D) photonic crystal (PC) array substrates for polymer:fullerene solar cells of which the active layer is made with blended films of poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). The 2D PC array substrates were fabricated by employing a nanosphere lithography technique. Two different hole depths (200 and 300 nm) were introduced for the 2D PC arrays to examine the hole depth effect on the light harvesting (trapping). The optical effect by the 2D PC arrays was investigated by the measurement of optical transmittance either in the direction normal to the substrate (direct transmittance) or in all directions (integrated transmittance). The results showed that the integrated transmittance was higher for the 2D PC array substrates than the conventional planar substrate at the wavelengths of ca. 400 nm, even though the direct transmittance of 2D PC array substrates was much lower over the entire visible light range. The short circuit current density (J(SC)) was higher for the device with the 2D PC array (200 nm hole depth) than the reference device. However, the device with the 2D PC array (300 nm hole depth) showed a slightly lower J(SC) value at a high light intensity in spite of its light harvesting effect proven at a lower light intensity.

Effect of chain length on thermal conversion of alkoxy-substituted copper phthalocyanine precursors.

PubMed

Fukuda, Takamitsu; Kikukawa, Yuu; Tsuruya, Ryota; Fuyuhiro, Akira; Ishikawa, Naoto; Kobayashi, Nagao

2011-11-21

A series of dialkoxy-substituted copper phthalocyanine (CuPc) precursors (4a-4d) have been prepared by treating phthalonitrile with the corresponding lithium alkoxide under mild conditions. The precursors exhibited high solubilities in common organic solvents, including acetone, toluene, tetrahydrofuran (THF), CH(2)Cl(2), and CHCl(3). Elongation of the alkoxy chains improved the solubilities of the precursors effectively, and accordingly, the butoxy-substituted derivative (4d) showed the highest solubility among 4a-4d. X-ray crystallography clarified that the conjugated skeletons of 4a-4d are all isostructural, and have two alkoxy groups in a syn-conformation fashion, leading to highly bent structures. Thermal conversions of the precursors examined by thermogravimetry (TG) and differential thermal analysis (DTA) demonstrate that 4a was converted into CuPc via two distinct exothermic processes in the 200-250 °C temperature range, while 4d exhibits only one exothermic signal in the DTA. In the field emission scanning electron microscopy (FESEM) images of 4a, the presence of two types of distinct crystal morphology (prismatic and plate-like crystals) can be recognized, implying that the two observed exothermic processes in the DTA can be attributed to the different crystal morphologies of the samples rather than the step-by-step elimination of the alkoxy groups. The thermal formation of CuPc from the precursors has been unambiguously confirmed by X-ray powder diffraction, UV-vis spectroscopy, and elemental analysis. The precursors were converted into CuPc at lower temperature with increasing chain length, presumably because of the increased void volume in the crystals. Thermal conversion performed in the solution phase results in a bright blue-colored solution with prominent absorption bands in the 650-700 nm region, strongly supporting the formation of CuPc.

Molecular imprinted opal closest-packing photonic crystals for the detection of trace 17β-estradiol in aqueous solution.

PubMed

Sai, Na; Wu, Yuntang; Sun, Zhong; Huang, Guowei; Gao, Zhixian

2015-11-01

A novel opal closest-packing (OCP) photonic crystal (PC) was prepared by the introduction of molecular imprinting technique into the OCP PC. This molecular imprinted (MI)-OCP PC was fabricated via a vertical convective self-assembly method using 17β-estradiol (E2) as template molecules for monitoring E2 in aqueous solution. Morphology characterization showed that the MI-OCP PC possessed a highly ordered three-dimensional (3D) periodically-ordered structure, showing the desired structural color. The proposed PC material displayed a reduced reflection intensity when detecting E2 in water environment, because the molecular imprinting recognition events make the optical characteristics of PC change. The Bragg diffraction intensity decreased by 19.864 a.u. with the increase of E2 concentration from 1.5 ng mL(-1) to 364.5 ng mL(-1) within 6 min, whereas there were no obvious peak intensity changes for estriol, estrone, cholesterol, testosterone and diethylstilbestrol, indicating that the MI-OCP PC had selective and rapid response for E2 molecules. The adsorption results showed that the OCP structure and homogeneous layers were created in the MI-OCP PC with higher adsorption capacity. Thus, it was learned the MI-OCP PC is a simple prepared, sensitive, selective, and easy operative material, which shows promising use in routine supervision for residue detection in food and environment. Copyright © 2015 Elsevier B.V. All rights reserved.

Photonic crystals on copolymer film for label-free detection of DNA hybridization.

PubMed

Su, Han; Cheng, Xin R; Endo, Tatsuro; Kerman, Kagan

2018-04-30

The presence of a single-nucleotide polymorphism in Apolipoprotein E4 gene is implicated with the increased risk of developing Alzheimer's disease (AD). In this study, detection of AD-related DNA oligonucleotide sequence associated with Apolipoprotein E4 gene sequence was achieved using localized-surface plasmon resonance (LSPR) on 2D-Photonic crystal (2D-PC) and Au-coated 2D-PC surfaces. 2D-PC surfaces were fabricated on a flexible copolymer film using nano-imprint lithography (NIL). The film surface was then coated with a dual-functionalized polymer to react with surface immobilized DNA probe. DNA hybridization was detected by monitoring the optical responses of either a Fresnel decrease in reflectance on 2D-PC surfaces or an increase in LSPR on Au-coated 2D-PC surfaces. The change in response due to DNA hybridization on the modified surfaces was also investigated using mismatched and non-complementary oligonucleotides sequences. The proof-of-concept results are promising towards the development of 2D-PC on copolymer film surfaces as miniaturized and wearable biosensors for various diagnostic and defense applications. Copyright © 2017 Elsevier B.V. All rights reserved.

Huge light-enhancement by coupling a Bowtie Nano-antenna's plasmonic resonance to a photonic crystal mode.

PubMed

Eter, Ali El; Grosjean, Thierry; Viktorovitch, Pierre; Letartre, Xavier; Benyattou, Taha; Baida, Fadi I

2014-06-16

We numerically demonstrate a drastic enhancement of the light intensity in the vicinity of the gap of Bowtie Nano-antenna (BA) through its coupling with Photonic Crystal (PC) resonator. The resulting huge energy transfer toward the BA is based on the coupling between two optical resonators (BA and PC membrane) of strongly unbalanced quality factors. Thus, these two resonators are designed so that the PC is only slightly perturbed in term of resonance properties. The proposed hybrid dielectric-plasmonic structure may open new avenues in the generation of deeply subwavelength intense optical sources, with direct applications in various domains such as data storage, non-linear optics, optical trapping and manipulation, microscopy, etc.

Band structure of one-dimensional photonic crystal with graphene layers using the Fresnel coefficients method

NASA Astrophysics Data System (ADS)

Jafari, A.; Rahmat, A.

2018-04-01

In this paper, we have calculated the band structure of an instance of one-dimensional photonic crystal (1DPC) composed of double-layered dielectrics via the Fresnel coefficients method. Then, we supposed the addition of a thin layer of graphene to each dielectric layer and the given photonic crystal (PC) composed of dielectric-graphene composites. The effects of graphene layers on the PC band structure were evaluated. We found out that according to the effective medium theory unlike the TE polarization, the electric permittivity of the dielectric layers changed at TM polarization. As such, the band structure of PC for TM polarization changed, too. Moreover, instead of bandgap related to “zero averaged refractive index” an approximately omnidirectional bandgap appeared and a related bandgap to “𝜀 = 0” disappeared. In addition, a new angular gap branch appeared at a new frequency at TM polarization in which the width of gap increased as the angle increased.

Porous photonic crystal external cavity laser biosensor

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

Huang, Qinglan; Peh, Jessie; Hergenrother, Paul J.

2016-08-15

We report the design, fabrication, and testing of a photonic crystal (PC) biosensor structure that incorporates a porous high refractive index TiO{sub 2} dielectric film that enables immobilization of capture proteins within an enhanced surface-area volume that spatially overlaps with the regions of resonant electromagnetic fields where biomolecular binding can produce the greatest shifts in photonic crystal resonant wavelength. Despite the nanoscale porosity of the sensor structure, the PC slab exhibits narrowband and high efficiency resonant reflection, enabling the structure to serve as a wavelength-tunable element of an external cavity laser. In the context of sensing small molecule interactions withmore » much larger immobilized proteins, we demonstrate that the porous structure provides 3.7× larger biosensor signals than an equivalent nonporous structure, while the external cavity laser (ECL) detection method provides capability for sensing picometer-scale shifts in the PC resonant wavelength caused by small molecule binding. The porous ECL achieves a record high figure of merit for label-free optical biosensors.« less

Detection of Myoglobin with an Open-Cavity-Based Label-Free Photonic Crystal Biosensor.

PubMed

Zhang, Bailin; Tamez-Vela, Juan Manuel; Solis, Steven; Bustamante, Gilbert; Peterson, Ralph; Rahman, Shafiqur; Morales, Andres; Tang, Liang; Ye, Jing Yong

2013-01-01

The label-free detection of one of the cardiac biomarkers, myoglobin, using a photonic-crystal-based biosensor in a total-internal-reflection configuration (PC-TIR) is presented in this paper. The PC-TIR sensor possesses a unique open optical microcavity that allows for several key advantages in biomolecular assays. In contrast to a conventional closed microcavity, the open configuration allows easy functionalization of the sensing surface for rapid biomolecular binding assays. Moreover, the properties of PC structures make it easy to be designed and engineered for operating at any optical wavelength. Through fine design of the photonic crystal structure, biochemical modification of the sensor surface, and integration with a microfluidic system, we have demonstrated that the detection sensitivity of the sensor for myoglobin has reached the clinically significant concentration range, enabling potential usage of this biosensor for diagnosis of acute myocardial infarction. The real-time response of the sensor to the myoglobin binding may potentially provide point-of-care monitoring of patients and treatment effects.

Extremely low-frequency Lamb wave band gaps in a sandwich phononic crystal thin plate

NASA Astrophysics Data System (ADS)

Shen, Li; Wu, Jiu Hui; Liu, Zhangyi; Fu, Gang

2015-11-01

In this paper, a kind of sandwich phononic crystal (PC) plate with silicon rubber scatterers embedded in polymethyl methacrylate (PMMA) matrix is proposed to demonstrate its low-frequency Lamb wave band gap (BG) characteristics. The dispersion relationship and the displacement vector fields of the basic slab modes and the locally resonant modes are investigated to show the BG formation mechanism. The anti-symmetric Lamb wave BG is further studied due to its important function in reducing vibration. The analysis on the BG characteristics of the PC through changing their geometrical parameters is performed. By optimizing the structure, a sandwich PC plate with a thickness of only 3 mm and a lower boundary (as low as 23.9 Hz) of the first anti-symmetric BG is designed. Finally, sound insulation experiment on a sandwich PC plate with the thickness of only 2.5 mm is conducted, showing satisfactory noise reduction effect in the frequency range of the anti-symmetric Lamb BG. Therefore, this kind of sandwich PC plate has potential applications in controlling vibration and noise in low-frequency ranges.

A highly-sensitive label-free biosensor based on two dimensional photonic crystals with negative refraction

NASA Astrophysics Data System (ADS)

Malmir, Narges; Fasihi, Kiazand

2017-11-01

In this work, we present a novel high-sensitive optical label-free biosensor based on a two-dimensional photonic crystal (2D PC). The suggested structure is composed of a negative refraction structure in a hexagonal lattice PC, along with a positive refraction structure which is arranged in a square lattice PC. The frequency shift of the transmission peak is measured respect to the changes of refractive indices of the studied materials (the blood plasma, water, dry air and normal air). The studied materials are filled into a W1 line-defect waveguide which is located in the PC structure with positive refraction (the microfluidic nanochannel). Our numerical simulations, which are based on finite-difference time-domain (FDTD) method, show that in the proposed structure, a sensitivity about 1100 nm/RIU and a transmission efficiency more than 75% can be achieved. With this design, to the best of our knowledge, the obtained sensitivity and the transmission efficiency are one of the highest values in the reported PC label-free biosensors.

Narrow Band Filter at 1550 nm Based on Quasi-One-Dimensional Photonic Crystal with a Mirror-Symmetric Heterostructure.

PubMed

Wang, Fang; Cheng, Yong Zhi; Wang, Xian; Zhang, Yi Nan; Nie, Yan; Gong, Rong Zhou

2018-06-27

In this paper, we present a high-efficiency narrow band filter (NBF) based on quasi-one-dimensional photonic crystal (PC) with a mirror symmetric heterostructure. Similarly to the Fabry-Perot-like resonance cavity, the alternately-arranged dielectric layers on both sides act as the high reflectance and the junction layers used as the defect mode of the quasi-one-dimensional PC, which can be designed as a NBF. The critical conditions for the narrow pass band with high transmittance are demonstrated and analyzed by simulation and experiment. The simulation results indicate that the transmission peak of the quasi-one-dimensional PC-based NBF is up to 95.99% at the telecommunication wavelength of 1550 nm, which agrees well with the experiment. Furthermore, the influences of the periodicity and thickness of dielectric layers on the transmission properties of the PC-based NBF also have been studied numerically. Due to its favorable properties of PC-based NBF, it is can be found to have many potential applications, such as detection, sensing, and communication.

15Mcps photon-counting X-ray computed tomography system using a ZnO-MPPC detector and its application to gadolinium imaging.

PubMed

Sato, Eiichi; Sugimura, Shigeaki; Endo, Haruyuki; Oda, Yasuyuki; Abudurexiti, Abulajiang; Hagiwara, Osahiko; Osawa, Akihiro; Matsukiyo, Hiroshi; Enomoto, Toshiyuki; Watanabe, Manabu; Kusachi, Shinya; Sato, Shigehiro; Ogawa, Akira; Onagawa, Jun

2012-01-01

15Mcps photon-counting X-ray computed tomography (CT) system is a first-generation type and consists of an X-ray generator, a turntable, a translation stage, a two-stage controller, a detector consisting of a 2mm-thick zinc-oxide (ZnO) single-crystal scintillator and an MPPC (multipixel photon counter) module, a counter card (CC), and a personal computer (PC). High-speed photon counting was carried out using the detector in the X-ray CT system. The maximum count rate was 15Mcps (mega counts per second) at a tube voltage of 100kV and a tube current of 1.95mA. Tomography is accomplished by repeated translations and rotations of an object, and projection curves of the object are obtained by the translation. The pulses of the event signal from the module are counted by the CC in conjunction with the PC. The minimum exposure time for obtaining a tomogram was 15min, and photon-counting CT was accomplished using gadolinium-based contrast media. Copyright © 2011 Elsevier Ltd. All rights reserved.

Gel-expanded to gel-condensed transition in neurofilament networks revealed by direct force measurements

NASA Astrophysics Data System (ADS)

Beck, Roy; Deek, Joanna; Jones, Jayna B.; Safinya, Cyrus R.

2010-01-01

Neurofilaments (NF)-the principal cytoskeletal constituent of myelinated axons in vertebrates-consist of three molecular-weight subunit proteins NF-L (low), NF-M (medium) and NF-H (high), assembled to form mature filaments with protruding unstructured C-terminus side arms. Liquid-crystal gel networks of side-arm-mediated neurofilament assemblies have a key role in the mechanical stability of neuronal processes. Disruptions of the neurofilament network, owing to neurofilament over-accumulation or incorrect side-arm interactions, are a hallmark of motor-neuron diseases including amyotrophic lateral sclerosis. Using synchrotron X-ray scattering, we report on a direct measurement of forces in reconstituted neurofilament gels under osmotic pressure (P). With increasing pressure near physiological salt and average phosphorylation conditions, NF-LMH, comprising the three subunits near in vivo composition, or NF-LH gels, undergo for P>Pc~10kPa, an abrupt non-reversible gel-expanded to gel-condensed transition. The transition indicates side-arm-mediated attractions between neurofilaments consistent with an electrostatic model of interpenetrating chains. In contrast, NF-LM gels remain in a collapsed state for PPc. These findings, which delineate the distinct roles of NF-M and NF-H in regulating neurofilament interactions, shed light on possible mechanisms for disruptions of optimal mechanical network properties.

Switchable Photonic Crystals Using One-Dimensional Confined Liquid Crystals for Photonic Device Application.

PubMed

Ryu, Seong Ho; Gim, Min-Jun; Lee, Wonsuk; Choi, Suk-Won; Yoon, Dong Ki

2017-01-25

Photonic crystals (PCs) have recently attracted considerable attention, with much effort devoted to photonic bandgap (PBG) control for varying the reflected color. Here, fabrication of a modulated one-dimensional (1D) anodic aluminum oxide (AAO) PC with a periodic porous structure is reported. The PBG of the fabricated PC can be reversibly changed by switching the ultraviolet (UV) light on/off. The AAO nanopores contain a mixture of photoresponsive liquid crystals (LCs) with irradiation-activated cis/trans photoisomerizable azobenzene. The resultant mixture of LCs in the porous AAO film exhibits a reversible PBG, depending on the cis/trans configuration of azobenzene molecules. The PBG switching is reliable over many cycles, suggesting that the fabricated device can be used in optical and photonic applications such as light modulators, smart windows, and sensors.

Crystal Data

National Institute of Standards and Technology Data Gateway

SRD 3 NIST Crystal Data (PC database for purchase)   NIST Crystal Data contains chemical, physical, and crystallographic information useful to characterize more than 237,671 inorganic and organic crystalline materials. The data include the standard cell parameters, cell volume, space group number and symbol, calculated density, chemical formula, chemical name, and classification by chemical type.

Four-Dimensional Screening Anti-Counterfeiting Pattern by Inkjet Printed Photonic Crystals.

PubMed

Hou, Jue; Zhang, Huacheng; Su, Bin; Li, Mingzhu; Yang, Qiang; Jiang, Lei; Song, Yanlin

2016-10-06

A four-dimensional screening anti-counterfeiting QR code composed of differently shaped photonic crystal (PC) dots has been fabricated that could display four images depending on different lighting conditions. By controlling the rheology of poly(dimethylsiloxane) (PDMS), three kinds of PC dots could be sequentially integrated into one pattern using the layer-by-layer printing strategy. The information can be encoded and stored in shapes and read out by the difference in optical properties. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Numerical investigation of diffraction of acoustic waves by phononic crystals

NASA Astrophysics Data System (ADS)

Moiseyenko, Rayisa P.; Declercq, Nico F.; Laude, Vincent

2012-05-01

Diffraction as well as transmission of acoustic waves by two-dimensional phononic crystals (PCs) composed of steel rods in water are investigated in this paper. The finite element simulations were performed in order to compute pressure fields generated by a line source that are incident on a finite size PC. Such field maps are analyzed based on the complex band structure for the infinite periodic PC. Finite size computations indicate that the exponential decrease of the transmission at deaf frequencies is much stronger than that in Bragg band gaps.

Multiwavelength ultralow-threshold lasing in quantum dot photonic crystal microcavities.

PubMed

Chakravarty, S; Bhattacharya, P; Chakrabarti, S; Mi, Z

2007-05-15

We demonstrate multiwavelength lasing of resonant modes in linear (L3) microcavities in a triangular-lattice 2D photonic crystal (PC) slab. The broad spontaneous emission spectrum from coupled quantum dots, modified by the PC microcavity, is studied as a function of the intensity of incident optical excitation. We observe lasing with an ultralow-threshold power of approximately 600 nW and an output efficiency of approximately 3% at threshold. Two other resonant modes exhibit weaker turnon characteristics and thresholds of approximately 2.5 and 200 microW, respectively.

Proton-coupled electron-transfer reduction of dioxygen catalyzed by a saddle-distorted cobalt phthalocyanine.

PubMed

Honda, Tatsuhiko; Kojima, Takahiko; Fukuzumi, Shunichi

2012-03-07

Proton-coupled electron-transfer reduction of dioxygen (O(2)) to afford hydrogen peroxide (H(2)O(2)) was investigated by using ferrocene derivatives as reductants and saddle-distorted (α-octaphenylphthalocyaninato)cobalt(II) (Co(II)(Ph(8)Pc)) as a catalyst under acidic conditions. The selective two-electron reduction of O(2) by dimethylferrocene (Me(2)Fc) and decamethylferrocene (Me(10)Fc) occurs to yield H(2)O(2) and the corresponding ferrocenium ions (Me(2)Fc(+) and Me(10)Fc(+), respectively). Mechanisms of the catalytic reduction of O(2) are discussed on the basis of detailed kinetics studies on the overall catalytic reactions as well as on each redox reaction in the catalytic cycle. The active species to react with O(2) in the catalytic reaction is switched from Co(II)(Ph(8)Pc) to protonated Co(I)(Ph(8)PcH), depending on the reducing ability of ferrocene derivatives employed. The protonation of Co(II)(Ph(8)Pc) inhibits the direct reduction of O(2); however, the proton-coupled electron transfer from Me(10)Fc to Co(II)(Ph(8)Pc) and the protonated [Co(II)(Ph(8)PcH)](+) occurs to produce Co(I)(Ph(8)PcH) and [Co(I)(Ph(8)PcH(2))](+), respectively, which react immediately with O(2). The rate-determining step is a proton-coupled electron-transfer reduction of O(2) by Co(II)(Ph(8)Pc) in the Co(II)(Ph(8)Pc)-catalyzed cycle with Me(2)Fc, whereas it is changed to the electron-transfer reduction of [Co(II)(Ph(8)PcH)](+) by Me(10)Fc in the Co(I)(Ph(8)PcH)-catalyzed cycle with Me(10)Fc. A single crystal of monoprotonated [Co(III)(Ph(8)Pc)](+), [Co(III)Cl(2)(Ph(8)PcH)], produced by the proton-coupled electron-transfer reduction of O(2) by Co(II)(Ph(8)Pc) with HCl, was obtained, and the crystal structure was determined in comparison with that of Co(II)(Ph(8)Pc). © 2012 American Chemical Society

Photonic-crystal membranes for optical detection of single nano-particles, designed for biosensor application.

PubMed

Grepstad, Jon Olav; Kaspar, Peter; Solgaard, Olav; Johansen, Ib-Rune; Sudbø, Aasmund S

2012-03-26

A sensor designed to detect bio-molecules is presented. The sensor exploits a planar 2D photonic crystal (PC) membrane with sub-micron thickness and through holes, to induce high optical fields that allow detection of nano-particles smaller than the diffraction limit of an optical microscope. We report on our design and fabrication of a PC membrane with a nano-particle trapped inside. We have also designed and built an imaging system where an optical microscope and a CCD camera are used to take images of the PC membrane. Results show how the trapped nano-particle appears as a bright spot in the image. In a first experimental realization of the imaging system, single particles with a radius of 75 nm can be detected.

Inorganic Crystal Structure Database (ICSD)

National Institute of Standards and Technology Data Gateway

SRD 84 FIZ/NIST Inorganic Crystal Structure Database (ICSD) (PC database for purchase)   The Inorganic Crystal Structure Database (ICSD) is produced cooperatively by the Fachinformationszentrum Karlsruhe(FIZ) and the National Institute of Standards and Technology (NIST). The ICSD is a comprehensive collection of crystal structure data of inorganic compounds containing more than 140,000 entries and covering the literature from 1915 to the present.

Up-regulated expression of cartilage intermediate-layer protein and ANK in articular hyaline cartilage from patients with calcium pyrophosphate dihydrate crystal deposition disease.

PubMed

Hirose, Jun; Ryan, Lawrence M; Masuda, Ikuko

2002-12-01

Excess accumulation of extracellular inorganic pyrophosphate (ePPi) in aged human cartilage is crucial in calcium pyrophosphate dihydrate (CPPD) crystal formation in cartilage matrix. Two sources of ePPi are ePPi-generating ectoenzymes (NTPPPH) and extracellular transport of intracellular PPi by ANK. This study was undertaken to evaluate the role of NTPPPH and ANK in ePPi elaboration, by investigating expression of NTPPPH enzymes (cartilage intermediate-layer protein [CILP] and plasma cell membrane glycoprotein 1 [PC-1]) and ANK in human chondrocytes from osteoarthritic (OA) articular cartilage containing CPPD crystals and without crystals. Chondrocytes were harvested from knee cartilage at the time of arthroplasty (OA with CPPD crystals [CPPD], n = 8; OA without crystals [OA], n = 10). Normal adult human chondrocytes (n = 1) were used as a control. Chondrocytes were cultured with transforming growth factor beta1 (TGFbeta1), which stimulates ePPi elaboration, and/or insulin-like growth factor 1 (IGF-1), which inhibits ePPi elaboration. NTPPPH and ePPi were measured in the media at 48 hours. Media CILP, PC-1, and ANK were determined by dot-immunoblot analysis. Chondrocyte messenger RNA (mRNA) was extracted for reverse transcriptase-polymerase chain reaction to study expression of mRNA for CILP, PC-1, and ANK. NTPPPH and ANK mRNA and protein were also studied in fresh frozen cartilage. Basal ePPi elaboration and NTPPPH activity in conditioned media from CPPD chondrocytes were elevated compared with normal chondrocytes, and tended to be higher compared with OA chondrocytes. Basal expression of mRNA for CILP (chondrocytes) and ANK (cartilage) was higher in both CPPD chondrocytes and CPPD cartilage extract than in OA or normal samples. PC-1 mRNA was less abundant in CPPD chondrocytes and cartilage extract than in OA chondrocytes and extract, although the difference was not significant. CILP, PC-1, and ANK protein levels were similar in CPPD, OA, and normal chondrocytes or cartilage extracts. Both CILP and ANK mRNA expression and ePPi elaboration were stimulated by TGFbeta1 and inhibited by IGF-1 in chondrocytes from all sources. CILP and ANK mRNA expression correlates with chondrocyte ePPi accumulation around CPPD and OA chondrocytes, and all respond similarly to growth factor stimulation. These findings suggest that up-regulated CILP and ANK expression contributes to higher ePPi accumulation from CPPD crystal-forming cartilage.

Controllable preparation of copper phthalocyanine single crystal nano column and its chlorine gas sensing properties

NASA Astrophysics Data System (ADS)

Zhao, Jianhong; Qiao, Zhenfang; Zhang, Yumin; Zou, Taoyu; Yu, Leiming; Luo, Li; Wang, Xiaoyan; Yang, Yiji; Wang, Hai; Tang, Libin

2016-09-01

The unsubstituted copper phthalocyanine (CuPc) single crystal nano columns were fabricated for the first time as chlorine (Cl2) gas sensors in this paper. The nano columns of CuPc have been prepared on different substrates via template-free physical vapor deposition (PVD) approach. The growth mechanism of CuPc nano column on quartz was explored and the same condition used on other substrates including glass, sapphire (C-plane<0001>, M-plane<10 1 ¯ 0 >, R-plane<1 1 ¯ 02 >), Si and SiO2/Si came to a same conclusion, which confirmed that the aligned growth of CuPc nano column is not substrate-dependent. And then the CuPc nano column with special morphology was integrated as in-situ sensor device which exhibits high sensitivity and selectivity towards Cl2 at room temperature with a minimum detection limit as low as 0.08 ppm. The response of sensor was found to increase linearly (26 ˜659 % ) with the increase for Cl2 within concentration range (0.08 ˜4.0 ppm ) . These results clearly demonstrate the great potential of the nano column growth and device integration approach for sensor device.

Photo-crystallization in a-Se layer structures: Effects of film-substrate interface-rigidity

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

Lindberg, G. P.; Gross, N.; Weinstein, B. A.

Amorphous selenium (a-Se) films deposited on rigid substrates can undergo photo-induced crystallization (PC) even at temperatures (T) well below the glass transition, T{sub g} ∼ 313 K. Substrate-generated shear strain is known to promote the PC process. In the present work, we explore the influence of different substrates (Si and glass), and different film-layer-substrate combinations, on the PC in a variety of a-Se films and film-structures. The intermediate layers (indium tin oxide and polyimide) are chosen to promote conductivity and/or to be a buffer against interface strain in structures of interest for digital imaging applications. The PC characteristics in these samples are evaluatedmore » and compared using optical microscopy, atomic-force microscopy, Raman mapping, and T-dependent Raman spectroscopy. Both the presence of a soft intermediate layer, and the thermal softening that occurs for T increasing through T{sub g}, inhibit the tendency for the onset of PC. The extensive PC mapping results in the wide range of samples studied here, as well as the suppression of PC near T{sub g} in this array of samples, strongly support the generality of this behavior. As a consequence, one may expect that the stability of a-Se films against PC can be enhanced by decreasing the rigidity of the film-substrate interface. In this regard, advanced film structures that employ flexible substrates, soft intermediate layers, and/or are designed to be operated near T{sub g} should be explored.« less

Dielectric and Energy Storage Properties of the Heterogeneous P(VDF-HFP)/PC Composite Films

NASA Astrophysics Data System (ADS)

Zhao, Xiaojia; Peng, Guirong; Zhan, Zaiji

2017-12-01

Polymer-based materials with a high discharge energy and low energy loss have attracted considerable attention for energy storage applications. A new class of polymer-based composite films composed of amorphous polycarbonate (PC) and poly(vinylidene fluoride-hexafluoropropylene) [P(VDF-HFP)] has been fabricated by simply solution blending followed by thermal treatment under vacuum. The results show that the diameter of the spherical phase for PC and the melting temperature of P(VDF-HFP) increase, and the crystallinity and crystallization temperature of P(VDF-HFP) decrease with increasing PC content. The phase transition from the polar β phase to weak polarity γ phase is induced by PC addition. Moreover, the Curie temperature of the P(VDF-HFP)/PC composite films shifts to a lower temperature. With the addition of PC, the permittivity, polarization and discharge energy of the P(VDF-HFP)/PC composite films slightly decrease. However, the energy loss is significantly reduced.

Novel organic LED structures based on a highly conductive polymeric photonic crystal electrode.

PubMed

Petti, Lucia; Rippa, Massimo; Capasso, Rossella; Nenna, Giuseppe; Del Mauro, Anna De Girolamo; Maglione, Maria Grazia; Minarini, Carla

2013-08-09

In this work we demonstrate the possibility to realize a novel unconventional ITO-free organic light emitting diode (OLED) utilizing a photonic polymeric electrode. Combining electron beam lithography and a plasma etching process to partially structure the highly conductive poly(3,4 ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) it is possible to realize an embedded photonic crystal (PC) structure. The realized PC-anode drastically reduces the light trapped in the OLED, demonstrating the possibility to eliminate further process stages and making it easier to use this technology even on rollable and flexible substrates.

Novel organic LED structures based on a highly conductive polymeric photonic crystal electrode

NASA Astrophysics Data System (ADS)

Petti, Lucia; Rippa, Massimo; Capasso, Rossella; Nenna, Giuseppe; De Girolamo Del Mauro, Anna; Grazia Maglione, Maria; Minarini, Carla

2013-08-01

In this work we demonstrate the possibility to realize a novel unconventional ITO-free organic light emitting diode (OLED) utilizing a photonic polymeric electrode. Combining electron beam lithography and a plasma etching process to partially structure the highly conductive poly(3,4 ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) it is possible to realize an embedded photonic crystal (PC) structure. The realized PC-anode drastically reduces the light trapped in the OLED, demonstrating the possibility to eliminate further process stages and making it easier to use this technology even on rollable and flexible substrates.

Critical CuI buffer layer surface density for organic molecular crystal orientation change

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

Ahn, Kwangseok; Kim, Jong Beom; Lee, Dong Ryeol, E-mail: drlee@ssu.ac.kr

We have determined the critical surface density of the CuI buffer layer inserted to change the preferred orientation of copper phthalocyanine (CuPc) crystals grown on the buffer layer. X-ray reflectivity measurements were performed to obtain the density profiles of the buffer layers and out-of-plane and 2D grazing-incidence X-ray diffraction measurements were performed to determine the preferred orientations of the molecular crystals. Remarkably, it was found that the preferred orientation of the CuPc film is completely changed from edge-on (1 0 0) to face-on (1 1 −2) by a CuI buffer layer with a very low surface density, so low thatmore » a large proportion of the substrate surface is bare.« less

Bis(tri-n-hexylsilyl oxide) silicon phthalocyanine: a unique additive in ternary bulk heterojunction organic photovoltaic devices.

PubMed

Lessard, Benoît H; Dang, Jeremy D; Grant, Trevor M; Gao, Dong; Seferos, Dwight S; Bender, Timothy P

2014-09-10

Previous studies have shown that the use of bis(tri-n-hexylsilyl oxide) silicon phthalocyanine ((3HS)2-SiPc) as an additive in a P3HT:PC61BM cascade ternary bulk heterojunction organic photovoltaic (BHJ OPV) device results in an increase in the short circuit current (J(SC)) and efficiency (η(eff)) of up to 25% and 20%, respectively. The previous studies have attributed the increase in performance to the presence of (3HS)2-SiPc at the BHJ interface. In this study, we explored the molecular characteristics of (3HS)2-SiPc which makes it so effective in increasing the OPV device J(SC) and η(eff. Initially, we synthesized phthalocyanine-based additives using different core elements such as germanium and boron instead of silicon, each having similar frontier orbital energies compared to (3HS)2-SiPc and tested their effect on BHJ OPV device performance. We observed that addition of bis(tri-n-hexylsilyl oxide) germanium phthalocyanine ((3HS)2-GePc) or tri-n-hexylsilyl oxide boron subphthalocyanine (3HS-BsubPc) resulted in a nonstatistically significant increase in JSC and η(eff). Secondly, we kept the silicon phthalocyanine core and substituted the tri-n-hexylsilyl solubilizing groups with pentadecyl phenoxy groups and tested the resulting dye in a BHJ OPV. While an increase in JSC and η(eff) was observed at low (PDP)2-SiPc loadings, the increase was not as significant as (3HS)2-SiPc; therefore, (3HS)2-SiPc is a unique additive. During our study, we observed that (3HS)2-SiPc had an extraordinary tendency to crystallize compared to the other compounds in this study and our general experience. On the basis of this observation, we have offered a hypothesis that when (3HS)2-SiPc migrates to the P3HT:PC61BM interface the reason for its unique performance is not solely due to its frontier orbital energies but also might be due to a high driving force for crystallization.

Subphthalocyanines Axially Substituted with a Tetracyanobuta-1,3-diene-Aniline Moiety: Synthesis, Structure, and Physicochemical Properties.

PubMed

Winterfeld, Kim A; Lavarda, Giulia; Guilleme, Julia; Sekita, Michael; Guldi, Dirk M; Torres, Tomás; Bottari, Giovanni

2017-04-19

A 1,1,4,4-tetracyanobuta-1,3-diene (TCBD)-aniline moiety has been introduced, for the first time, at the axial position of two subphthalocyanines (SubPcs) peripherally substituted with hydrogen (H 12 SubPc) or fluorine atoms (F 12 SubPc). Single-crystal X-ray analysis of both SubPc-TCBD-aniline systems showed that each conjugate is a racemic mixture of two atropisomers resulting from the almost orthogonal geometry adopted by the axial TCBD unit, which were separated by chiral high-performance liquid chromatography. Remarkably, the single-crystal X-ray structure of one atropisomer of each SubPc-TCBD-aniline conjugate has been solved, allowing to unambiguously assign the atropisomers' absolute configuration, something, to the best of our knowledge, unprecedented in TCBD-based conjugates. Moreover, the physicochemical properties of both SubPc-TCBD-aniline racemates have been investigated using a wide range of electrochemical as well as steady-state and time-resolved spectroscopic techniques. Each of the two SubPc-TCBD-aniline conjugates presents a unique photophysical feature never observed before in SubPc chemistry. As a matter of fact, H 12 SubPc-TCBD-aniline showed significant ground-state charge transfer interactions between the H 12 SubPc macrocycle and the electron-withdrawing TCBD unit directly attached at its axial position. In contrast, F 12 SubPc-TCBD-aniline gave rise to an intense, broad emission, which red shifts upon increasing the solvent polarity and stems from an excited complex (i.e., an exciplex). Such an exciplex emission, which has also no precedent in TCBD chemistry, results from intramolecular interactions in the excited state between the electron-rich aniline and the F 12 SubPc π-surface, two molecular fragments kept in spatial proximity by the "unique" three-dimensional geometry adopted by the F 12 SubPc-TCBD-aniline. Complementary transient absorption studies were carried out on both SubPc-TCBD-aniline derivatives, showing the occurrence, in both cases, of photoinduced charge separation and corroborating the formation of the aforementioned intramolecular exciplex in terms of a radical ion pair stabilized through-space.

Mcps-range photon-counting x-ray computed tomography system

NASA Astrophysics Data System (ADS)

Sato, Eiichi; Oda, Yasuyuki; Abudurexiti, Abulajiang; Hagiwara, Osahiko; Enomoto, Toshiyuki; Sugimura, Shigeaki; Endo, Haruyuki; Sato, Shigehiro; Ogawa, Akira; Onagawa, Jun

2011-10-01

10 Mcps photon counting was carried out using a detector consisting of a 2.0 mm-thick ZnO (zinc oxide) single-crystal scintillator and an MPPC (multipixel photon counter) module in an X-ray computed tomography (CT) system. The maximum count rate was 10 Mcps (mega counts per second) at a tube voltage of 70 kV and a tube current of 2.0 mA. Next, a photon-counting X-ray CT system consists of an X-ray generator, a turntable, a scan stage, a two-stage controller, the ZnO-MPPC detector, a counter card (CC), and a personal computer (PC). Tomography is accomplished by repeated linear scans and rotations of an object, and projection curves of the object are obtained by the linear scan with a scan velocity of 25 mm/s. The pulses of the event signal from the module are counted by the CC in conjunction with the PC. The exposure time for obtaining a tomogram was 600 s at a scan step of 0.5 mm and a rotation step of 1.0°, and photon-counting CT was accomplished using iodine-based contrast media.

Tetra-methyl substituted copper (II) phthalocyanine as a hole injection enhancer in organic light-emitting diodes

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

Wang, Yu-Long; Xu, Jia-Ju; Lin, Yi-Wei

2015-10-15

We have enhanced hole injection and lifetime in organic light-emitting diodes (OLEDs) by incorporating the isomeric metal phthalocyanine, CuMePc, as a hole injection enhancer. The OLED devices containing CuMePc as a hole injection layer (HIL) exhibited higher luminous efficiency and operational lifetime than those using a CuPc layer and without a HIL. The effect of CuMePc thickness on device performance was investigated. Atomic force microscope (AFM) studies revealed that the thin films were smooth and uniform because the mixture of CuMePc isomers depressed crystallization within the layer. This may have caused the observed enhanced hole injection, indicating that CuMePc ismore » a promising HIL material for highly efficient OLEDs.« less

Training HBCU Faculty and Students in Prostate Cancer (PC) Research: Signal Transduction and Receptor-Inhibitor Interactions in the Progress of PC

DTIC Science & Technology

2007-03-01

Katrina. Nicole Bell has continued to work on the crystal structures of tyrosine kinase inhibitors. A senior, Aviva Baird , has joined the group and...Sabbatical Internship, Marian Merrell Dow Pharmaceuticals. Participated in drug discovery of compounds that I synthesized; techniques included tumor

Possible Domain Formation In PE/PC Bilayers Containing High Cholesterol

NASA Astrophysics Data System (ADS)

Hein, Matthew; Hussain, Fazle; Huang, Juyang

2015-03-01

Cholesterol is a significant component of animal cell membranes, and its presence has the effects of not only adding rigidity to the lipid bilayer, but also leading to the formation of lipid domains. Two other lipids of interest are phosphatidylethanolamine (PE), which constitutes about 45 percent of the phospholipids found in human nervous tissues, and phosphatidylcholine (PC), which is found in every cell of the human body. The maximum solubility of cholesterol is the highest mole fraction of cholesterol that the lipid bilayer can retain, at which point cholesterol begins to precipitate out to form cholesterol monohydrate crystals. We have measured the maximum solubility of cholesterol in mixtures of 16:0-18:1PE and 16:0-18:1PC using a new light scattering technique, which utilizes the anisotropic nature of light scattering by cholesterol crystals. This new method is highly accurate and reproducible. Our results show that the maximum solubility of cholesterol increases linearly as a function of the molar ratio POPC/(POPE+POPC), which suggests possible domain formation in mixtures of PE and PC containing maximum amount of cholesterol.

Photonic crystals: emerging biosensors and their promise for point-of-care applications.

PubMed

Inan, Hakan; Poyraz, Muhammet; Inci, Fatih; Lifson, Mark A; Baday, Murat; Cunningham, Brian T; Demirci, Utkan

2017-01-23

Biosensors are extensively employed for diagnosing a broad array of diseases and disorders in clinical settings worldwide. The implementation of biosensors at the point-of-care (POC), such as at primary clinics or the bedside, faces impediments because they may require highly trained personnel, have long assay times, large sizes, and high instrumental cost. Thus, there exists a need to develop inexpensive, reliable, user-friendly, and compact biosensing systems at the POC. Biosensors incorporated with photonic crystal (PC) structures hold promise to address many of the aforementioned challenges facing the development of new POC diagnostics. Currently, PC-based biosensors have been employed for detecting a variety of biotargets, such as cells, pathogens, proteins, antibodies, and nucleic acids, with high efficiency and selectivity. In this review, we provide a broad overview of PCs by explaining their structures, fabrication techniques, and sensing principles. Furthermore, we discuss recent applications of PC-based biosensors incorporated with emerging technologies, including telemedicine, flexible and wearable sensing, smart materials and metamaterials. Finally, we discuss current challenges associated with existing biosensors, and provide an outlook for PC-based biosensors and their promise at the POC.

Control of Mechanical Properties of Thermoplastic Polyurethane Elastomers by Restriction of Crystallization of Soft Segment

PubMed Central

Kojio, Ken; Furukawa, Mutsuhisa; Nonaka, Yoshiteru; Nakamura, Sadaharu

2010-01-01

Mechanical properties of thermoplastic polyurethane elastomers based on either polyether or polycarbonate (PC)-glycols, 4,4’-dipheylmethane diisocyanate (1,1’-methylenebis(4-isocyanatobenzene)), 1,4-butanediol, were controlled by restriction of crystallization of polymer glycols. For the polyether glycol based-polyurethane elastomers (PUEs), poly(oxytetramethylene) glycol (PTMG), and PTMG incorporating dimethyl groups (PTG-X) and methyl side groups (PTG-L) were employed as a polymer glycol. For the PC-glycol, the randomly copolymerized PC-glycols with hexamethylene (C6) and tetramethylene (C4) units between carbonate groups with various composition ratios (C4/C6 = 0/100, 50/50, 70/30 and 90/10) were employed. The degree of microphase separation and mechanical properties of both the PUEs were investigated using differential scanning calorimetry, dynamic viscoelastic property measurements and tensile testing. Mechanical properties could be controlled by changing the molar ratio of two different monomer components. PMID:28883371

The crystalline structure of copper phthalocyanine films on ZnO(1100).

PubMed

Cruickshank, Amy C; Dotzler, Christian J; Din, Salahud; Heutz, Sandrine; Toney, Michael F; Ryan, Mary P

2012-09-05

The structure of copper phthalocyanine (CuPc) thin films (5-100 nm) deposited on single-crystal ZnO(1100) substrates by organic molecular beam deposition was determined from grazing-incidence X-ray diffraction reciprocal space maps. The crystal structure was identified as the metastable polymorph α-CuPc, but the molecular stacking was found to vary depending on the film thickness: for thin films, a herringbone arrangement was observed, whereas for films thicker than 10 nm, coexistence of both the herringbone and brickstone arrangements was found. We propose a modified structure for the herringbone phase with a larger monoclinic β angle, which leads to intrastack Cu-Cu distances closer to those in the brickstone phase. This structural basis enables an understanding of the functional properties (e.g., light absorption and charge transport) of (opto)electronic devices fabricated from CuPc/ZnO hybrid systems.

Atomic resolution ADF-STEM imaging of organic molecular crystal of halogenated copper phthalocyanine.

PubMed

Haruta, Mitsutaka; Yoshida, Kaname; Kurata, Hiroki; Isoda, Seiji

2008-05-01

Annular dark-field (ADF) scanning transmission electron microscopy (STEM) measurements are demonstrated for the first time to be applicable for acquiring Z-contrast images of organic molecules at atomic resolution. High-angle ADF imaging by STEM is a new technique that provides incoherent high-resolution Z-contrast images for organic molecules. In the present study, low-angle ADF-STEM is successfully employed to image the molecular crystal structure of hexadecachloro-Cu-phthalocyanine (Cl16-CuPc), an organic molecule. The structures of CuPc derivatives (polyhalogenated CuPc with Br and Cl) are determined quantitatively using the same technique to determine the occupancy of halogens at each chemical site. By comparing the image contrasts of atomic columns, the occupancy of Br is found to be ca. 56% at the inner position, slightly higher than that for random substitution and in good agreement with previous TEM results.

How large B-factors can be in protein crystal structures.

PubMed

Carugo, Oliviero

2018-02-23

Protein crystal structures are potentially over-interpreted since they are routinely refined without any restraint on the upper limit of atomic B-factors. Consequently, some of their atoms, undetected in the electron density maps, are allowed to reach extremely large B-factors, even above 100 square Angstroms, and their final positions are purely speculative and not based on any experimental evidence. A strategy to define B-factors upper limits is described here, based on the analysis of protein crystal structures deposited in the Protein Data Bank prior 2008, when the tendency to allow B-factor to arbitrary inflate was limited. This B-factor upper limit (B_max) is determined by extrapolating the relationship between crystal structure average B-factor and percentage of crystal volume occupied by solvent (pcVol) to pcVol =100%, when, ab absurdo, the crystal contains only liquid solvent, the structure of which is, by definition, undetectable in electron density maps. It is thus possible to highlight structures with average B-factors larger than B_max, which should be considered with caution by the users of the information deposited in the Protein Data Bank, in order to avoid scientifically deleterious over-interpretations.

Off-axis spectral beam combining of Bragg reflection waveguide photonic crystal diode lasers

NASA Astrophysics Data System (ADS)

Sun, Fangyuan; Wang, Lijie; Zhao, Yufei; Hou, Guanyu; Shu, Shili; Zhang, Jun; Peng, Hangyu; Tian, Sicong; Tong, Cunzhu; Wang, Lijun

2018-06-01

The spectral beam combining (SBC) of Bragg reflection waveguide photonic crystal (BRW-PC) diode lasers was studied for the first time. An off-axis feedback system was constructed using a stripe mirror and a spatial filter to control beam quality in the external cavity. It was found that the BRW-PC diode lasers with a low divergence and a circular beam provided a simplified and cost-effective SBC. The off-axis feedback broke the beam quality limit of a single element, and an M 2 factor of 3.8 times lower than that of a single emitter in the slow axis was demonstrated.

2D photonic crystal complete band gap search using a cyclic cellular automaton refination

NASA Astrophysics Data System (ADS)

González-García, R.; Castañón, G.; Hernández-Figueroa, H. E.

2014-11-01

We present a refination method based on a cyclic cellular automaton (CCA) that simulates a crystallization-like process, aided with a heuristic evolutionary method called differential evolution (DE) used to perform an ordered search of full photonic band gaps (FPBGs) in a 2D photonic crystal (PC). The solution is proposed as a combinatorial optimization of the elements in a binary array. These elements represent the existence or absence of a dielectric material surrounded by air, thus representing a general geometry whose search space is defined by the number of elements in such array. A block-iterative frequency-domain method was used to compute the FPBGs on a PC, when present. DE has proved to be useful in combinatorial problems and we also present an implementation feature that takes advantage of the periodic nature of PCs to enhance the convergence of this algorithm. Finally, we used this methodology to find a PC structure with a 19% bandgap-to-midgap ratio without requiring previous information of suboptimal configurations and we made a statistical study of how it is affected by disorder in the borders of the structure compared with a previous work that uses a genetic algorithm.

A General Method for Discovering Inhibitors of Protein–DNA Interactions Using Photonic Crystal Biosensors

PubMed Central

Chan, Leo L.; Pineda, Maria; Heeres, James T.; Hergenrother, Paul J.; Cunningham, Brian T.

2009-01-01

Protein–DNA interactions are essential for fundamental cellular processes such as transcription, DNA damage repair, and apoptosis. As such, small molecule disruptors of these interactions could be powerful tools for investigation of these biological processes, and such compounds would have great potential as therapeutics. Unfortunately, there are few methods available for the rapid identification of compounds that disrupt protein–DNA interactions. Here we show that photonic crystal (PC) technology can be utilized to detect protein–DNA interactions, and can be used in a high-throughput screening mode to identify compounds that prevent protein–DNA binding. The PC technology is used to detect binding between protein–DNA interactions that are DNA-sequence-dependent (the bacterial toxin–antitoxin system MazEF) and those that are DNA-sequence-independent (the human apoptosis inducing factor (AIF)). The PC technology was further utilized in a screen for inhibitors of the AIF–DNA interaction, and through this screen aurin tricarboxylic acid was identified as the first in vitro inhibitor of AIF. The generality and simplicity of the photonic crystal method should enable this technology to find broad utility for identification of compounds that inhibit protein–DNA binding. PMID:18582039

Polarization beam splitter based on a photonic crystal heterostructure.

PubMed

Schonbrun, E; Wu, Q; Park, W; Yamashita, T; Summers, C J

2006-11-01

The design and characterization of a photonic crystal (PC) polarization beam splitter (PBS) that operates with an extinction ratio of greater than 15 dB for both polarizations are presented. The PBS is fabricated on a silicon-on-insulator (SOI) wafer where the input and output ports consist of 5 mum wide ridge waveguides. A large spectral shift is observed in the dispersion plots of the lowest-order even (TE-like) and odd (TM-like) modes due to the SOI confinement. Because of this shift, the TE-like mode is close to a directional gap at the top of the band, and the TM-like mode is in a low-frequency regime where the dispersion surface is almost isotropic. We show that the TE-like mode has very high reflection at the interface between the two PCs, whereas the TM-like mode exhibits a very high transmission.

Phononic Crystal Tunable via Ferroelectric Phase Transition

NASA Astrophysics Data System (ADS)

Xu, Chaowei; Cai, Feiyan; Xie, Shuhong; Li, Fei; Sun, Rong; Fu, Xianzhu; Xiong, Rengen; Zhang, Yi; Zheng, Hairong; Li, Jiangyu

2015-09-01

Phononic crystals (PCs) consisting of periodic materials with different acoustic properties have potential applications in functional devices. To realize more smart functions, it is desirable to actively control the properties of PCs on demand, ideally within the same fabricated system. Here, we report a tunable PC made of Ba0.7Sr0.3Ti O3 (BST) ceramics, wherein a 20-K temperature change near room temperature results in a 20% frequency shift in the transmission spectra induced by a ferroelectric phase transition. The tunability phenomenon is attributed to the structure-induced resonant excitation of A0 and A1 Lamb modes that exist intrinsically in the uniform BST plate, while these Lamb modes are sensitive to the elastic properties of the plate and can be modulated by temperature in a BST plate around the Curie temperature. The study finds opportunities for creating tunable PCs and enables smart temperature-tuned devices such as the Lamb wave filter or sensor.

Photoconductive and electro-optic effects in (Cd,Mg)Te single crystals measured in an experiment-on-chip configuration

NASA Astrophysics Data System (ADS)

Serafini, John; Hossain, A.; James, R. B.; Guziewicz, M.; Kruszka, R.; Słysz, W.; Kochanowska, D.; Domagala, J. Z.; Mycielski, A.; Sobolewski, Roman

2017-07-01

We present our studies on both photoconductive (PC) and electro-optic (EO) responses of (Cd,Mg)Te single crystals. In an In-doped Cd0.92Mg0.08Te single crystal, subpicosecond electrical pulses were optically generated via a PC effect, coupled into a transmission line, and, subsequently, detected using an internal EO sampling scheme, all in the same (Cd,Mg)Te material. For photo-excitation and EO sampling, we used femtosecond optical pulses generated by the same Ti:sapphire laser with the wavelengths of 410 and 820 nm, respectively. The shortest transmission line distance between the optical excitation and EO sampling points was 75 μm. By measuring the transient waveforms at different distances from the excitation point, we calculated the transmission-line complex propagation factor, as well as the THz frequency attenuation factor and the propagation velocity, all of which allowed us to reconstruct the electromagnetic transient generated directly at the excitation point, showing that the original PC transient was subpicosecond in duration with a fall time of ˜500 fs. Finally, the measured EO retardation, together with the amount of the electric-field penetration, allowed us to determine the magnitude of the internal EO effect in our (Cd,Mg)Te crystal. The obtained THz-frequency EO coefficient was equal to 0.4 pm/V, which is at the lower end among the values reported for CdTe-based ternaries, apparently, due to the disorientation of the tested crystal that resulted in the non-optimal EO measurement condition.

Photoconductive and electro-optic effects in (Cd,Mg)Te single crystals measured in an experiment-on-chip configuration

DOE PAGES

Serafini, John; Hossain, A.; James, R. B.; ...

2017-07-03

We present our studies on both photoconductive (PC) and electro-optic (EO) responses of (Cd,Mg)Te single crystals. In an In-doped Cd 0.92Mg 0.08Te single crystal, subpicosecond electrical pulses were optically generated via a PC effect, coupled into a transmission line, and, subsequently, detected using an internal EO sampling scheme, all in the same (Cd,Mg)Te material. For photo-excitation and EO sampling, we used femtosecond optical pulses generated by the same Ti:sapphire laser with the wavelength 410 and 820 nm, respectively. The shortest transmission line distance between the optical excitation and EO sampling points was 75 μm. By measuring the transient waveforms atmore » different distances from the excitation point, we calculated the transmission-line complex propagation factor, as well as the THz frequency attenuation factor and the propagation velocity, all of which allowed us to reconstruct the electromagnetic transient generated directly at the excitation point, showing that the original PC transient was subpicosecond in duration with a fall time of ~500 fs. Finally, the measured EO retardation, together with the amount of the electric-field penetration, allowed us to determine the magnitude of the internal EO effect in our (Cd,Mg)Te crystal. The obtained THz-frequency EO coefficient was equal to 0.4 pm/V, which is at the lower end among the values reported for CdTe-based ternaries, due to a twinned structure and misalignment of the tested (Cd,Mg)Te crystal.« less

Study of optical reflectance properties in 1D annular photonic crystal containing double negative (DNG) metamaterials

NASA Astrophysics Data System (ADS)

Srivastava, Sanjeev K.; Aghajamali, Alireza

2016-05-01

Theoretical investigation of photonic band gaps or reflection bands in one-dimensional annular photonic crystal (APC) containing double negative (DNG) metamaterials and air has been presented. The proposed structure consists of the alternate layers of dispersive DNG material and air immersed in free space. In order to study photonic band gaps we obtain the reflectance spectrum of the annular PC by employing the transfer matrix method (TMM) in the cylindrical waves for both TE and TM polarizations. In this work we study the effect of azimuthal mode number (m) and starting radius (ρ0) on the three band gaps viz. zero averaged refractive index (zero-nbar) gap, zero permittivity (zero- ε) and zero permeability (zero- μ) gaps. It is found that for m ≥ 1 , zero- μ gap appears in TE mode and zero- ε gap appears in TM mode. The width of both zero- μ and zero- ε gap increases by increasing m values, but the enhancement of zero- μ gap is more appreciable. Also, the effect of ρ0 on the three band gaps (reflection bands) of annular PC structure at the given m-number has been studied, for both TE and TM polarizations. The result shows that in both polarizations zero- ε and zero- μ gaps decreases when ρ0 increases, whereas zero-nbar gap remains invariant.

Origin of temporal compositional trends in monogenetic vent eruptions: Insights from the crystal cargo in the Papoose Canyon sequence, Big Pine Volcanic Field, CA

NASA Astrophysics Data System (ADS)

Gao, Ruohan; Lassiter, John C.; Ramirez, Gabrielle

2017-01-01

Many monogenetic vents display systematic temporal-compositional variations over the course of eruption. Previous studies have proposed that these trends may reflect variable degrees of crustal assimilation, or melting and mixing of heterogeneous mantle source(s). Discrimination between these two endmember hypotheses is critical for understanding the plumbing systems of monogenetic volcanoes, which pose a significant volcanic hazard in many areas. In this study, we examine the Papoose Canyon (PC) monogenetic vent in the Big Pine Volcanic Field (BPVF), which had been well characterized for temporal-compositional variations in erupted basalts. We present new major and trace element and Sr-Nd-Pb-O isotopic data from the PC "crystal cargo" (phenocrysts and xenoliths). Comparison of "crystal cargo" and host basalt provides new constraints on the history of magma storage, fractionation, and crustal contamination that are obscured in the bulk basalts due to pre- and syn-eruptive magma mixing processes. The abundances of phenocrysts and ultramafic xenoliths in the PC sequence decrease up-section. Olivine and clinopyroxene phenocrysts span a wide range of Mg# (77-89). The majority of phenocrysts are more evolved than olivine or clinopyroxene in equilibrium with their host basalts (Mg# = 68- 71, equilibrium Fo ≈ 85- 89). In addition, the ultramafic xenoliths display cumulate textures. Olivine and clinopyroxene from ultramafic xenoliths have Mg# (73-87) similar to the phenocrysts, and lower than typical mantle peridotites. Sr-Nd-Pb isotope compositions of the xenoliths are similar to early PC basalts. Finally, many clinopyroxene phenocrysts and clinopyroxene in xenoliths have trace element abundances in equilibrium with melts that are more enriched than the erupted basalts. These features suggest that the phenocrysts and xenoliths derive from melt that is more fractionated and enriched than erupted PC basalts. Pressure constraints suggest phenocrysts and ultramafic xenoliths crystallized at ∼5-7 kbar, corresponding to mid-crust depths. Correlations between HFSE depletion and Sr-Nd-Pb isotopic compositions, high δ18 O values in olivines, and radiogenic Os isotopic compositions in whole rocks also suggest incorporation of a crustally contaminated component. We propose that the phenocrysts and ultramafic xenoliths derive from melts that ponded and fractionated and assimilated continental crust, possibly in mid-crustal sills. These melts were drained and mixed with more primitive melts as the eruption began, and the temporal-compositional trends and decreasing crystal phase abundances reflect gradual deflation and exhaustion of these sills as the eruption progressed. The isotopic variations in the PC sequence span much of the compositional range observed in the BPVF. Evidence for variable crustal contamination of PC basalts suggests that much of the isotopic variation observed in the BPVF may also reflect crustal contamination rather than mantle source heterogeneity as previously proposed. In addition, evidence of pre-eruptive magma ponding and fractionation, if applicable to other monogenetic vents, may have significant implications for monitoring and hazard assessment of monogenetic volcano fields.

EDITORIAL: Photonic Crystal Devices

NASA Astrophysics Data System (ADS)

Bhattacharya, Pallab K.

2007-05-01

The engineering of electromagnetic modes at optical frequencies in artificial dielectric structures with periodic and random variation of the refractive index, enabling control of the radiative properties of the materials and photon localization, was first proposed independently by Yablonovitch and John in 1987. It is possible to control the flow of light in the periodic dielectric structures, known as photonic crystals (PC). As light waves scatter within the photonic crystal, destructive interference cancels out light of certain wavelengths, thereby forming a photonic bandgap, similar to the energy bandgap for electron waves in a semiconductor. Photons whose energies lie within the gap cannot propagate through the periodic structure. This property can be used to make a low-loss cavity. If a point defect, such as one or more missing periods, is introduced into the periodic structure a region is obtained within which the otherwise forbidden wavelengths can be locally trapped. This property can be used to realize photonic microcavities. Similarly, a line of defects can serve as a waveguide. While the realization of three-dimensional (3D) photonic crystals received considerable attention initially, planar two-dimensional (2D) structures are currently favoured because of their relative ease of fabrication. 2D photonic crystal structures provide most of the functionality of 3D structures. These attributes have generated worldwide research and development of sub-μm and μm size active and passive photonic devices such as single-mode and non- classical light sources, guided wave devices, resonant cavity detection, and components for optical communication. More recently, photonic crystal guided wave devices are being investigated for application in microfludic and biochemical sensing. Photonic crystal devices have been realized with bulk, quantum well and quantum dot active regions. The Cluster of articles in this issue of Journal of Physics D: Applied Physics provides a glimpse of some of the most recent advances in the application of photonic crystals. The modelling of PC defect-mode cavities are described by Zhou et al. Ye and co-authors describe the concept and realization of a novel 3D silicon-based spiral PC. It is, in fact, the only article on 3D PCs. The design and realization of ultra-high Q heterostructure PC nanocavities are described by Song and co-authors. The concept of self-collimation of light in PCs and its applications are presented by Prather and co-workers. Experimental and numerical studies on the negative refraction related phenomenon in 2D PCs are the subject of the next article by Ozbay and co-authors. The emerging subject of slow light generation, control and propagation in PCs is presented in the next two articles by Baba and Mori and by Krauss. Finally, the progress made in the development of PC microcavity lasers and electrically injected microcavity light emitters and arrays is described, respectively, by O'Brien et al and by Chakravarty et al. It is hoped that readers will get a sense of the exciting developments and the possibilities presented by heterostructure photonic crystals and their devices from reading the articles in this Cluster.

Positron Interactions with Oriented Polymers and with Chiral Quartz Crystals

NASA Astrophysics Data System (ADS)

Wu, Fei

Positron annihilation in various materials has been applied to characterize microstructure for decades. In this work, PALS was used to study material nanostructure, with a focus on the size and density of free volume and hole relaxation properties in polycarbonate (PC) and polymethylmethacrylate (PMMA); fundamental studies of polarized positron interaction with chiral crystals were also studied. Free volume relaxation in PC and PMMA with different levels of simple shear orientation was studied by PALS. Effects of applied pressure on the free volume recovery were evaluated. Combining the bulk- and pressure-dependent PALS analyses, the removal of applied pressure led to free-volume relaxation in all samples studied. The alignment of the polymer chains and free-volume holes imposes molecular restrictions on the molecular mobility of both PC and PMMA in their glassy states. Results indicated that the relaxation of the free volume holes at temperatures below glass transition is mostly reversible. Longitudinally polarized positron particles were used to reveal asymmetric interactions in chiral quartz crystals. Experimental results showed a significant intensity difference in free positronium annihilation for left handed (LH) and right handed (RH) chiral quartz crystals. Doppler broadening energy spectra (DBES) of z-cut LH or RH quartz disks at different angles were also measured by an "S parameter" to probe the observed difference. It was found that obtained annihilation energy difference of DBES was in agreement with the result of positron annihilation in bulk chiral crystals. PALS was used to compare different orientations and confirm asymmetric interactions in natural versus synthetic quartz LH and RH crystals in z and non-z orientations. Significant lifetime and intensity differences in free positronium annihilation for LH and RH quartz crystals were observed. The trend was found to be same in the related crystallographic orientations of the LH or RH crystals; the direction of incident positrons, z or non-z, did not affect the observed differences in lifetime and intensity trends. The results confirmed the existence of differential interactions of positronium with the asymmetric lattice structures of LH and RH quartz crystals.

Insertion of two-dimensional photonic crystal pattern on p-GaN layer of GaN-based light-emitting diodes using bi-layer nanoimprint lithography.

PubMed

Byeon, Kyeong-Jae; Hwang, Seon-Yong; Hong, Chang-Hee; Baek, Jong Hyeob; Lee, Heon

2008-10-01

Nanoimprint lithography (NIL) was adapted to fabricate two-dimensional (2-D) photonic crystal (PC) pattern on the p-GaN layer of InGaN/GaN multi quantum well light-emitting diodes (LEDs) structure to improve the light extraction efficiency. For the uniform transfer of the PC pattern, a bi-layer imprinting method with liquid phase resin was used. The p-GaN layer was patterned with a periodic array of holes by an inductively coupled plasma etching process, based on SiCl4/Ar plasmas. As a result, 2-D photonic crystal patterns with 144 nm, 200 nm and 347 nm diameter holes were uniformly formed on the p-GaN layer and the photoluminescence (PL) intensity of each patterned LED samples was increased by more than 2.6 times, as compared to that of the un-patterned LED sample.

Polymer blend effect on molecular alignment induced by contact freezing of mesogenic phthalocyanine

NASA Astrophysics Data System (ADS)

Kitagawa, Takahiro; Fiderana Ramananarivo, Mihary; Fujii, Akihiko; Ozaki, Masanori

2018-04-01

The polymer blend effect in the fabrication of uniaxially oriented thin films of a mesogenic phthalocyanine, 1,4,8,11,15,18,22,25-octahexylphthalocyanine (C6PcH2), by contact freezing was studied. Contact freezing was induced by thermal stimulation to a supercooled liquid crystal state of the mixture of C6PcH2 and poly(3-hexylthiophene) (P3HT). With the blending of P3HT with C6PcH2 at an appropriate blend ratio, the cracks observed in a pure C6PcH2 film disappeared while maintaining the uniaxial alignment of C6PcH2. The polymer blend effect was discussed by taking the anisotropic optical absorption and molecular stacking structure in the thin films into consideration.

One-way mode transmission in one-dimensional phononic crystal plates

NASA Astrophysics Data System (ADS)

Zhu, Xuefeng; Zou, Xinye; Liang, Bin; Cheng, Jianchun

2010-12-01

We investigate theoretically the band structures of one-dimensional phononic crystal (PC) plates with both antisymmetric and symmetric structures, and show how unidirectional transmission behavior can be obtained for either antisymmetric waves (A modes) or symmetric waves (S modes) by exploiting mode conversion and selection in the linear plate systems. The theoretical approach is illustrated for one PC plate example where unidirectional transmission behavior is obtained in certain frequency bands. Employing harmonic frequency analysis, we numerically demonstrate the one-way mode transmission for the PC plate with finite superlattice by calculating the steady-state displacement fields under A modes source (or S modes source) in forward and backward direction, respectively. The results show that the incident waves from A modes source (or S modes source) are transformed into S modes waves (or A modes waves) after passing through the superlattice in the forward direction and the Lamb wave rejections in the backward direction are striking with a power extinction ratio of more than 1000. The present structure can be easily extended to two-dimensional PC plate and efficiently encourage practical studies of experimental realization which is believed to have much significance for one-way Lamb wave mode transmission.

Interaction Between the Biotin Carboxyl Carrier Domain and the Biotin Carboxylase Domain in Pyruvate Carboxylase from Rhizobium etli†

PubMed Central

Lietzan, Adam D.; Menefee, Ann L.; Zeczycki, Tonya N.; Kumar, Sudhanshu; Attwood, Paul V.; Wallace, John C.; Cleland, W. Wallace; Maurice, Martin St.

2011-01-01

Pyruvate carboxylase (PC) catalyzes the ATP-dependent carboxylation of pyruvate to oxaloacetate, an important anaplerotic reaction in mammalian tissues. To effect catalysis, the tethered biotin of PC must gain access to active sites in both the biotin carboxylase domain and the carboxyl transferase domain. Previous studies have demonstrated that a mutation of threonine 882 to alanine in PC from Rhizobium etli renders the carboxyl transferase domain inactive and favors the positioning of biotin in the biotin carboxylase domain. We report the 2.4 Å resolution X-ray crystal structure of the Rhizobium etli PC T882A mutant which reveals the first high-resolution description of the domain interaction between the biotin carboxyl carrier protein domain and the biotin carboxylase domain. The overall quaternary arrangement of Rhizobium etli PC remains highly asymmetrical and is independent of the presence of allosteric activator. While biotin is observed in the biotin carboxylase domain, its access to the active site is precluded by the interaction between Arg353 and Glu248, revealing a mechanism for regulating carboxybiotin access to the BC domain active site. The binding location for the biotin carboxyl carrier protein domain demonstrates that tethered biotin cannot bind in the biotin carboxylase domain active site in the same orientation as free biotin, helping to explain the difference in catalysis observed between tethered biotin and free biotin substrates in biotin carboxylase enzymes. Electron density located in the biotin carboxylase domain active site is assigned to phosphonoacetate, offering a probable location for the putative carboxyphosphate intermediate formed during biotin carboxylation. The insights gained from the T882A Rhizobium etli PC crystal structure provide a new series of catalytic snapshots in PC and offer a revised perspective on catalysis in the biotin-dependent enzyme family. PMID:21958016

Photonic crystal enhanced fluorescence using a quartz substrate to reduce limits of detection

PubMed Central

Pokhriyal, Anusha; Lu, Meng; Chaudhery, Vikram; Huang, Cheng-Sheng; Schulz, Stephen; Cunningham, Brian T.

2010-01-01

A Photonic Crystal (PC) surface fabricated upon a quartz substrate using nanoimprint lithography has been demonstrated to enhance light emission from fluorescent molecules in close proximity to the PC surface. Quartz was selected for its low autofluorescence characteristics compared to polymer-based PCs, improving the detection sensitivity and signal-to-noise ratio (SNR) of PC Enhanced Fluorescence (PCEF). Nanoimprint lithography enables economical fabrication of the subwavelength PCEF surface structure over entire 1x3 in2 quartz slides. The demonstrated PCEF surface supports a transverse magnetic (TM) resonant mode at a wavelength of λ = 632.8 nm and an incident angle of θ = 11°, which amplifies the electric field magnitude experienced by surface-bound fluorophores. Meanwhile, another TM mode at a wavelength of λ = 690 nm and incident angle of θ = 0° efficiently directs the fluorescent emission toward the detection optics. An enhancement factor as high as 7500 × was achieved for the detection of LD-700 dye spin-coated upon the PC, compared to detecting the same material on an unpatterned glass surface. The detection of spotted Alexa-647 labeled polypeptide on the PC exhibits a 330 × SNR improvement. Using dose-response characterization of deposited fluorophore-tagged protein spots, the PCEF surface demonstrated a 140 × lower limit of detection compared to a conventional glass substrate. PMID:21164826

The Lamb wave bandgap variation of a locally resonant phononic crystal subjected to thermal deformation

NASA Astrophysics Data System (ADS)

Zhu, Yun; Li, Zhen; Li, Yue-ming

2018-05-01

A study on dynamical characteristics of a ternary locally resonant phononic crystal (PC) plate (i.e., hard scatterer with soft coating periodically disperse in stiff host matrix) is carried out in this paper. The effect of thermal deformation on the structure stiffness, which plays an important role in the PC's dynamical characteristics, is considered. Results show that both the start and the stop frequency of bandgap shift to higher range with the thermal deformation. In particular, the characteristics of band structure change suddenly at critical buckling temperature. The effect of thermal deformation could be utilized for tuning of phononic band structures, which can promote their design and further applications.

Bottom-up photonic crystal cavities formed by patterned III-V nanopillars.

PubMed

Scofield, Adam C; Shapiro, Joshua N; Lin, Andrew; Williams, Alex D; Wong, Ping-Show; Liang, Baolai L; Huffaker, Diana L

2011-06-08

We report on the formation and optical properties of bottom-up photonic crystal (PC) cavities formed by III-V nanopillars (NPs) via catalyst-free selective-area metal-organic chemical vapor deposition on masked GaAs substrates. This method of NP synthesis allows for precise lithographic control of NP position and diameter enabling simultaneous formation of both the photonic band gap (PBG) region and active gain region. The PBG and cavity resonance are determined by independently tuning the NP radius r, pitch a, and height h in the respective masked areas. Near-infrared emission at 970 nm is achieved from axial GaAs/InGaAs heterostructures with in situ passivation by laterally grown InGaP shells. To achieve out-of-plane optical confinement, the PC cavities are embedded in polydimethylsiloxane (PDMS) and removed from the growth substrate. Spatially and spectrally resolved 77 K photoluminescence demonstrates a strong influence of the PBG resonance on device emission. Resonant peaks are observed in the emission spectra of PC cavities embedded in PDMS.

6 Mcps photon-counting X-ray computed tomography system using a 25 mm/s-scan linear LSO-MPPC detector and its application to gadolinium imaging

NASA Astrophysics Data System (ADS)

Sato, Eiichi; Oda, Yasuyuki; Abudurexiti, Abulajiang; Hagiwara, Osahiko; Matsukiyo, Hiroshi; Osawa, Akihiro; Enomoto, Toshiyuki; Watanabe, Manabu; Kusachi, Shinya; Sugimura, Shigeaki; Endo, Haruyuki; Sato, Shigehiro; Ogawa, Akira; Onagawa, Jun

2011-12-01

6 Mcps photon counting was carried out using a detector consisting of a 1.0 mm-thick LSO [Lu 2(SiO 4)O] single-crystal scintillator and an MPPC (multipixel photon counter) module in an X-ray computed tomography (CT) system. The maximum count rate was 6 Mcps (mega counts per second) at a tube voltage of 100 kV and a tube current of 0.91 mA. Next, a photon-counting X-ray CT system consists of an X-ray generator, a turntable, a scan stage, a two-stage controller, the LSO-MPPC detector, a counter card (CC), and a personal computer (PC). Tomography is accomplished by repeated linear scans and rotations of an object, and projection curves of the object are obtained by the linear scan with a scan velocity of 25 mm/s. The pulses of the event signal from the module are counted by the CC in conjunction with the PC. The exposure time for obtaining a tomogram was 600 s at a scan step of 0.5 mm and a rotation step of 1.0°, and photon-counting CT was accomplished using gadolinium-based contrast media.

Mcps-range photon-counting X-ray computed tomography system utilizing an oscillating linear-YAP(Ce) photon detector

NASA Astrophysics Data System (ADS)

Oda, Yasuyuki; Sato, Eiichi; Abudurexiti, Abulajiang; Hagiwara, Osahiko; Osawa, Akihiro; Matsukiyo, Hiroshi; Enomoto, Toshiyuki; Watanabe, Manabu; Kusachi, Shinya; Sugimura, Shigeaki; Endo, Haruyuki; Sato, Shigehiro; Ogawa, Akira; Onagawa, Jun

2011-07-01

High-speed X-ray photon counting is useful for discriminating photon energy, and the counting can be used for constructing an X-ray computed tomography (CT) system. A photon-counting X-ray CT system consists of an X-ray generator, a turntable, an oscillation linear detector, a two-stage controller, a multipixel photon counter (MPPC) module, a 1.0 mm-thick crystal (scintillator) of YAP(Ce) (cerium-doped yttrium aluminum perovskite), a counter card (CC), and a personal computer (PC). Tomography is accomplished by repeating the linear scanning and the rotation of an object, and projection curves of the object are obtained by the linear scanning using the detector consisting of an MPPC module, the YAP(Ce), and a scan stage. The pulses of the event signal from the module are counted by the CC in conjunction with the PC. Because the lower level of the photon energy was roughly determined by a comparator in the module, the average photon energy of the X-ray spectra increased with increase in the lower-level voltage of the comparator at a constant tube voltage. The maximum count rate was approximately 3 Mcps (mega counts per second), and photon-counting CT was carried out.

High-speed photon-counting x-ray computed tomography system utilizing a multipixel photon counter

NASA Astrophysics Data System (ADS)

Sato, Eiichi; Enomoto, Toshiyuki; Watanabe, Manabu; Hitomi, Keitaro; Takahashi, Kiyomi; Sato, Shigehiro; Ogawa, Akiro; Onagawa, Jun

2009-07-01

High-speed photon counting is useful for discriminating photon energy and for decreasing absorbed dose for patients in medical radiography, and the counting is usable for constructing an x-ray computed tomography (CT) system. A photon-counting x-ray CT system is of the first generation type and consists of an x-ray generator, a turn table, a translation stage, a two-stage controller, a multipixel photon counter (MPPC) module, a 1.0-mm-thick LSO crystal (scintillator), a counter card (CC), and a personal computer (PC). Tomography is accomplished by repeating the linear scanning and the rotation of an object, and projection curves of the object are obtained by the linear scanning using the detector consisting of a MPPC module and the LSO. The pulses of the event signal from the module are counted by the CC in conjunction with the PC. The lower level of the photon energy is roughly determined by a comparator circuit in the module, and the unit of the level is the photon equivalent (pe). Thus, the average photon energy of the x-ray spectra increases with increasing the lower-level voltage of the comparator. The maximum count rate was approximately 20 Mcps, and energy-discriminated CT was roughly carried out.

Microstructural and electrical properties of Al/n-type Si Schottky diodes with Au-CuPc nanocomposite films as interlayer

NASA Astrophysics Data System (ADS)

Reddy, P. R. Sekhar; Janardhanam, V.; Jyothi, I.; Chang, Han-Soo; Lee, Sung-Nam; Lee, Myung Sun; Reddy, V. Rajagopal; Choi, Chel-Jong

2017-11-01

Au-CuPc nanocomposite films were prepared by simultaneous evaporation of Au and CuPc with various Au and CuPc concentrations. Microstructural analysis of Au-CuPc films revealed elongated Au cluster formation from isolated Au nanoclusters with increasing Au concentration associated with coalescence of Au clusters. Au-CuPc films with different compositions were employed as interlayer in Al/n-Si Schottky diode. Barrier height and series resistance of the Al/n-Si Schottky diode with Au-CuPc interlayer decreased with increasing Au concentration. This could be associated with the enhancement of electron tunneling between neighboring clusters due to decrease in spacing of Au clusters and formation of conducting paths through the composite material. Interface state density of the Al/n-Si Schottky diode with Au-CuPc interlayer increased with increasing Au concentration. This might be because the inclusion of metal decreases the crystallinity and crystal size of the polymer matrix accompanied by the formation of local defect sites at the places of metal nucleation.

Synthesis, X-ray structure, magnetic resonance, and DFT analysis of a soluble copper(II) phthalocyanine lacking C-H bonds.

PubMed

Moons, Hans; Łapok, Łukasz; Loas, Andrei; Van Doorslaer, Sabine; Gorun, Sergiu M

2010-10-04

The synthesis, crystal structure, and electronic properties of perfluoro-isopropyl-substituted perfluorophthalocyanine bearing a copper atom in the central cavity (F(64)PcCu) are reported. While most halogenated phthalocyanines do not exhibit long-term order sufficient to form large single crystals, this is not the case for F(64)PcCu. Its crystal structure was determined by X-ray analysis and linked to the electronic properties determined by electron paramagnetic resonance (EPR). The findings are corroborated by density functional theory (DFT) computations, which agree well with the experiment. X-band continuous-wave EPR spectra of undiluted F(64)PcCu powder, indicate the existence of isolated metal centers. The electron-withdrawing effect of the perfluoroalkyl (R(f)) groups significantly enhances the complexes solubility in organic solvents like alcohols, including via their axial coordination. This coordination is confirmed by X-band (1)H HYSCORE experiments and is also seen in the solid state via the X-ray structure. Detailed X-band CW-EPR, X-band Davies and Mims ENDOR, and W-band electron spin-echo-detected EPR studies of F(64)PcCu in ethanol allow the determination of the principal g values and the hyperfine couplings of the metal, nitrogen, and fluorine nuclei. Comparison of the g and metal hyperfine values of F(64)PcCu and other PcCu complexes in different matrices reveals a dominant effect of the matrix on these EPR parameters, while variations in the ring substituents have only a secondary effect. The relatively strong axial coordination occurs despite the diminished covalency of the C-N bonds and potentially weakening Jahn-Teller effects. Surprisingly, natural abundance (13)C HYSCORE signals could be observed for a frozen ethanol solution of F(64)PcCu. The (13)C nuclei contributing to the HYSCORE spectra could be identified as the pyrrole carbons by means of DFT. Finally, (19)F ENDOR and easily observable paramagnetic NMR were found to relate well to the DFT computations, revealing negligible isotropic hyperfine (Fermi contact) contributions. The single-site isolation in solution and solid state and the relatively strong coordination of axial ligands, both attributed to the introduction of R(f) groups, are features important for materials and catalyst design.

Design on compatible stealth photonic crystal of nearmiddle infrared and 1.06 μm laser

NASA Astrophysics Data System (ADS)

Zhang, Ji-kui; Wang, Jia-Chun; Wang, Qi-Chao

2016-01-01

In the near and middle infrared atmospheric window, infrared stealth material require a low absorptivity (which means a low emissivity according to Kirchhoff's law of black body), at the same time, it also requires high absorptivity so as to decrease the reflectance at military laser wavelength of 1.06μm. Under this circumstances, compatible stealth of infrared and laser is an urgent demand, but the demand is ambivalent for conventional materials. Photonic crystal (PC), as a new type of artificial periodic structure function material, can realize broadband thermal infrared stealth based on its high-reflection photon forbidden band(also called photonic band gap). The high-reflection photon forbidden band of PC can be adjusted to near and middle infrared wave band through some rational methods. When a defect was added into the periodic structure of PC, a "hole-digging" reflection spectrum, which is high absorption at military laser wavelength of 1.06μm, can be achieved, so compatible stealth of near and middle infrared and military laser wavelength of 1.06μm can be achieved too. In this paper, we selected near and middle infrared-transparent materials, Te and MgF2 , as high refractive index and low refractive index material respectively, and designed a one-dimensional one-defect-mode PC whose photon forbidden band was broadened to 1-5μm by constructing two photonic crystals into one. The optical property of the PC was calculated by Transfer matrix method(TMM) of thin-film optical theory, and the results shows that the as-designed PC has a high spectral reflectance in the near and middle infrared band, among which the reflectivity in 1.68μm 5.26μm band reached more than 90%, and the 2.48 5.07μm band even reached 99.99%. The result also shows that between the band gap of 1-5μm, there are one defect mode locating in the wavelength of 1.06μm, whose reflectance is below 0.70%, which means its spectral absorptivity is greater than 99.30%. All the above we have discussed proved that this "hole-digging spectrum" PC can realize the compatible stealth of near and middle infrared and 1.06μm military laser.

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

Gupta, Shashaank; Belianinov, Alex; Okatan, Mahmut B

(001)pc textured K0.5Na0.5NbO3 (KNN) ceramic was found to exhibit a 65% improvement in the longitudinal piezoelectric response as compared to its random counterpart. Piezoresponse force microscopy study revealed the existence of larger 180 and non-180 domains for textured ceramic as compared to that of the random ceramic. Improvement in piezoresponse by the development of (001)pc texture is discussed in terms of the crystallographic nature of KNN and domain morphology. A comparative analysis performed with a rhombohedral composition suggested that the improvement in longitudinal piezoresponse of polycrystalline ceramics by the development of (001)pc texture is limited by the crystal structure.

High-throughput and in situ EDXRD investigation on the formation of two new metal aminoethylphosphonates - Ca(O{sub 3}PC{sub 2}H{sub 4}NH{sub 2}) and Ca(OH)(O{sub 3}PC{sub 2}H{sub 4}NH{sub 3}){center_dot}2H{sub 2}O

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

Schmidt, Corinna; Feyand, Mark; Rothkirch, Andre

2012-04-15

The system Ca{sup 2+}/2-aminoethylphosphonic acid/H{sub 2}O/NaOH was systematically investigated using high-throughput methods. The experiments led to one new compound Ca(O{sub 3}PC{sub 2} H{sub 4}NH{sub 2}) (1) and the crystal structure was determined using in house X-ray powder diffraction data (monoclinic, P2{sub 1}/c, a=9.7753(3), b=6.4931(2), c=8.4473(2) A, {beta}=106.46(2) Degree-Sign , V=514.20(2) A{sup 3}, Z=4). The formation of 1 was investigated by in situ energy dispersive X-ray diffraction measurements (EDXRD) at beamline F3 at HASYLAB (light source DORIS III), DESY, Hamburg. An intermediate, Ca(OH)(O{sub 3}PC{sub 2}H{sub 4}NH{sub 3}){center_dot}2H{sub 2}O (2), was observed and could be isolated from the reaction mixture at ambientmore » temperatures by quenching the reaction. The crystal structure of 2 was determined from XRPD data using synchrotron radiation (monoclinic, P2{sub 1}/m, a=11.2193(7), b=7.1488(3), c=5.0635(2) A, {beta}=100.13(4) Degree-Sign , V=399.78(3) A{sup 3}, Z=2). - Graphical abstarct: The detailed in situ energy dispersive X-ray diffraction (EDXRD) investigation on the formation of the new inorganic-organic hybrid compound Ca(O{sub 3}PC{sub 2}H{sub 4}NH{sub 2}) leads to the discovery of a new crystalline intermediate phase. Both crystal structures were elucidated using X-ray powder diffraction data. Highlights: Black-Right-Pointing-Pointer High-throughput investigation led to new metal aminoethylphosphonate Ca(O{sub 3}PC{sub 2}H{sub 4}NH{sub 2}). Black-Right-Pointing-Pointer The formation of Ca(O{sub 3}PC{sub 2}H{sub 4}NH{sub 2}) was followed by in situ EDXRD measurements. Black-Right-Pointing-Pointer The crystalline intermediate Ca(O{sub 3}PC{sub 2}H{sub 4}NH{sub 3})(OH){center_dot}2H{sub 2}O was discovered. Black-Right-Pointing-Pointer Isolation of Ca(O{sub 3}PC{sub 2}H{sub 4}NH{sub 3})(OH){center_dot}2H{sub 2}O was accomplished by quenching experiments. Black-Right-Pointing-Pointer The structures were determined using X-ray powder diffraction data.« less

Polymer photonic crystal slab waveguides

NASA Astrophysics Data System (ADS)

Liguda, C.; Böttger, G.; Kuligk, A.; Blum, R.; Eich, M.; Roth, H.; Kunert, J.; Morgenroth, W.; Elsner, H.; Meyer, H. G.

2001-04-01

We present details of the fabrication, calculations, and transmission measurements for finite two-dimensional (2D) polymer photonic crystal (PC) slab waveguides, which were fabricated from a benzocyclobutene polymer on a low refractive index substrate from Teflon. A square air hole lattice (500 nm lattice constant, 300 nm hole diameter) was realized by electron beam lithography and reactive ion etching. Polarization and wavelength dependent transmission results show TE-like and TM-like stop gaps at 1.3 μm excitation wavelengths and are in good agreement with the calculated data obtained by 2D and three-dimensional finite difference time domain methods. Transmission was suppressed by 15 dB in the center of the TE-like stop gap for a PC length of ten lattice constants.

Electromagnetic diode based on photonic crystal cavity with embedded highly dispersive meta-interface

NASA Astrophysics Data System (ADS)

Chen, Yongqiang; Dong, Lijuan; Xu, Xiaohu; Jiang, Jun; Shi, Yunlong

2017-12-01

In this paper, we propose a scheme for subwavelength electromagnetic diodes by employing a photonic crystal (PC) cavity with embedded electromagnetically induced-transparency (EIT)-like highly dispersive meta-interface. A nonreciprocal response, with 21.5 dB transmission light contrast and 12.3 dBm working power, is conceptually demonstrated in a microstrip transmission line system with asymmetric absorption and nonlinear medium inclusion. Such high-contrast transmission and relatively low-threshold diode action stem from the composite PC-EIT mechanism. This mechanism not only possesses a large quality factor and strong localization of fields but also does not enlarge the device volume and drastically reduce transmittance. Our findings should be beneficial for the design of new and practical metamaterial-enabled nonlinear devices.

Morphology-defined interaction of copper phthalocyanine with O2/H2O

NASA Astrophysics Data System (ADS)

Muckley, Eric S.; Miller, Nicholas; Jacobs, Christopher B.; Gredig, Thomas; Ivanov, Ilia N.

2016-10-01

Copper phthalocyanine (CuPc) is an important hole transport layer for organic photovoltaics (OPVs), but interaction with ambient gas/vapor may lead to changes in its electronic properties and limit OPV device lifetimes. CuPc films of thickness 25 and 100 nm were grown by thermal sublimation at 25°C, 150°C, and 250°C in order to vary morphology. We measured electrical resistance and film mass in situ during exposure to controlled pulses of O2 and H2O vapor. CuPc films deposited at 250°C showed a factor of 5 higher uptake of O2 as detected by a quartz crystal microbalance (QCM), possibly due to the formation of β-CuPc at T>200°C which allows higher O2 mobility between stacked molecules. While weight-based measurements stabilize after ˜10 min of gas exposure, resistance response stabilizes over times >1 h, suggesting that mass change occurs by rapid adsorption at active surface sites whereas resistive response is dominated by slow diffusion of adsorbates into the bulk film. The 25 nm films exhibit higher resistive response than 100 nm films after an hour of O2/H2O exposure due to fast analyte diffusion down to the film/electrode interface. We found evidence of decoupling of CuPc from the gold-coated QCM crystal due to preferential adsorption of O2/H2O molecules on gold.

Achieving an Accurate Surface Profile of a Photonic Crystal for Near-Unity Solar Absorption in a Super Thin-Film Architecture.

PubMed

Kuang, Ping; Eyderman, Sergey; Hsieh, Mei-Li; Post, Anthony; John, Sajeev; Lin, Shawn-Yu

2016-06-28

In this work, a teepee-like photonic crystal (PC) structure on crystalline silicon (c-Si) is experimentally demonstrated, which fulfills two critical criteria in solar energy harvesting by (i) its Gaussian-type gradient-index profile for excellent antireflection and (ii) near-orthogonal energy flow and vortex-like field concentration via the parallel-to-interface refraction effect inside the structure for enhanced light trapping. For the PC structure on 500-μm-thick c-Si, the average reflection is only ∼0.7% for λ = 400-1000 nm. For the same structure on a much thinner c-Si ( t = 10 μm), the absorption is near unity (A ∼ 99%) for visible wavelengths, while the absorption in the weakly absorbing range (λ ∼ 1000 nm) is significantly increased to 79%, comparing to only 6% absorption for a 10-μm-thick planar c-Si. In addition, the average absorption (∼94.7%) of the PC structure on 10 μm c-Si for λ = 400-1000 nm is only ∼3.8% less than the average absorption (∼98.5%) of the PC structure on 500 μm c-Si, while the equivalent silicon solid content is reduced by 50 times. Furthermore, the angular dependence measurements show that the high absorption is sustained over a wide angle range (θinc = 0-60°) for teepee-like PC structure on both 500 and 10-μm-thick c-Si.

Porous Coordination Polymer Based on Bipyridinium Carboxylate Linkers with High and Reversible Ammonia Uptake.

PubMed

Leroux, Maxime; Mercier, Nicolas; Allain, Magali; Dul, Marie-Claire; Dittmer, Jens; Kassiba, Abdel Hadi; Bellat, Jean-Pierre; Weber, Guy; Bezverkhyy, Igor

2016-09-06

The zwitterionic bipyridinium carboxylate ligand 1,1'-bis(4-carboxyphenyl)-4,4'-bipyridinium (pc1) in the presence of cadmium chloride affords novel porous coordination polymers (PCPs): [Cd4(pc1)3Cl6]·CdCl4·guest (1) crystallizing in the P3̅1c space group. In the structure, [Cd4Cl6(CO2)6] building units are linked together by six pc1 ligands, leading to a 3D high-symmetrical network exhibiting hexagonal channels along the c axis. The walls of this PCP consist of cationic electron-acceptor bipyridinium units. The PCP 1 reversibly adsorbs H2O and CH3OH up to about 0.1 g/g at saturation showing the adsorption isotherms characteristic of a moderately hydrophilic sorbent. Adsorption of ammonia (NH3) follows a different pattern, reaching an exceptional uptake of 0.39 g/g (22.3 mmol/g) after the first adsorption cycle. Although the crystalline structure of 1 collapses after the first adsorption, the solid can be regenerated and maintains the capacity of 0.29 g/g (17 mmol/g) in the following cycles. We found that the high NH3 uptake is due to a combination of pore filling taking place below 150 h·Pa and chemisorption occurring at higher pressures. The latter process was shown to involve two phenomena: (i) coordination of NH3 molecules to Cd(2+) cations as follows from (113)Cd NMR and (ii) strong donor-acceptor interactions between NH3 molecules and pc1 ligands.

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

Cody, Vivian, E-mail: cody@hwi.buffalo.edu; University of Buffalo, Buffalo, NY 14260; Pace, Jim

The structures of mouse DHFR holo enzyme and a ternary complex with NADPH and a potent inhibitor are described. It has been shown that 2, 4-diamino-6-arylmethylpteridines and 2, 4-diamino-5-arylmethylpyrimidines containing an O-carboxylalkyloxy group in the aryl moiety are potent and selective inhibitors of the dihydrofolate reductase (DHFR) from opportunistic pathogens such as Pneumocystis carinii, the causative agent of Pneumocystis pneumonia in HIV/AIDS patients. In order to understand the structure–activity profile observed for a series of substituted dibenz[b, f]azepine antifolates, the crystal structures of mouse DHFR (mDHFR; a mammalian homologue) holo and ternary complexes with NADPH and the inhibitor 2, 4-diamino-6-(2′-hydroxydibenz[b,more » f]azepin-5-yl)methylpteridine were determined to 1.9 and 1.4 Å resolution, respectively. Structural data for the ternary complex with the potent O-(3-carboxypropyl) inhibitor PT684 revealed no electron density for the O-carboxylalkyloxy side chain. The side chain was either cleaved or completely disordered. The electron density fitted the less potent hydroxyl compound PT684a. Additionally, cocrystallization of mDHFR with NADPH and the less potent 2′-(4-carboxybenzyl) inhibitor PT682 showed no electron density for the inhibitor and resulted in the first report of a holoenzyme complex despite several attempts at crystallization of a ternary complex. Modeling data of PT682 in the active site of mDHFR and P. carinii DHFR (pcDHFR) indicate that binding would require ligand-induced conformational changes to the enzyme for the inhibitor to fit into the active site or that the inhibitor side chain would have to adopt an alternative binding mode to that observed for other carboxyalkyloxy inhibitors. These data also show that the mDHFR complexes have a decreased active-site volume as reflected in the relative shift of helix C (residues 59–64) by 0.6 Å compared with pcDHFR ternary complexes. These data are consistent with the greater inhibitory potency against pcDHFR.« less

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

Cody, V.; Pace, J.; Rosowsky, A.

It has been shown that 2,4-diamino-6-arylmethylpteridines and 2,4-diamino-5-arylmethylpyrimidines containing an O-carboxylalkyloxy group in the aryl moiety are potent and selective inhibitors of the dihydrofolate reductase (DHFR) from opportunistic pathogens such as Pneumocystis carinii, the causative agent of Pneumocystis pneumonia in HIV/AIDS patients. In order to understand the structure-activity profile observed for a series of substituted dibenz[b,f]azepine antifolates, the crystal structures of mouse DHFR (mDHFR; a mammalian homologue) holo and ternary complexes with NADPH and the inhibitor 2,4-diamino-6-(2{prime}-hydroxydibenz[b,f]azepin-5-yl)methylpteridine were determined to 1.9 and 1.4 A resolution, respectively. Structural data for the ternary complex with the potent O-(3-carboxypropyl) inhibitor PT684 revealed nomore » electron density for the O-carboxylalkyloxy side chain. The side chain was either cleaved or completely disordered. The electron density fitted the less potent hydroxyl compound PT684a. Additionally, cocrystallization of mDHFR with NADPH and the less potent 2{prime}-(4-carboxybenzyl) inhibitor PT682 showed no electron density for the inhibitor and resulted in the first report of a holoenzyme complex despite several attempts at crystallization of a ternary complex. Modeling data of PT682 in the active site of mDHFR and P. carinii DHFR (pcDHFR) indicate that binding would require ligand-induced conformational changes to the enzyme for the inhibitor to fit into the active site or that the inhibitor side chain would have to adopt an alternative binding mode to that observed for other carboxyalkyloxy inhibitors. These data also show that the mDHFR complexes have a decreased active-site volume as reflected in the relative shift of helix C (residues 59-64) by 0.6 A compared with pcDHFR ternary complexes. These data are consistent with the greater inhibitory potency against pcDHFR.« less

MCT: A UK Retrospective—Reminiscences of a Crystal Grower

NASA Astrophysics Data System (ADS)

Capper, Peter

2017-09-01

The essentials of bulk Bridgman growth of mercury cadmium telluride (MCT) are outlined, together with some background to its use in the UK. It is still being used in a few niche applications, e.g., long-wavelength photoconductive (PC) detectors for space programs, and as material for infrared (IR) optical components. The latter requires very short-wavelength and/or larger-diameter material, and the challenges and successes in these areas are outlined. Use of a new source of high-purity silica, together with continual improvements in element purification, from our in-house tellurium zone refining and mercury distillation, reduced the carrier concentration consistently to sub-1014 cm-3, which helped to further improve PC device performance. An offer is made to supply bulk wafers to the wider community for research and development (R&D) purposes. The benefits of IR-related books, published over the past 30 years, to the community are described and a challenge laid down to continue this process of information dissemination into the future, in either hard-copy form or online versions.

Specific phospholipid binding to Na,K-ATPase at two distinct sites.

PubMed

Habeck, Michael; Kapri-Pardes, Einat; Sharon, Michal; Karlish, Steven J D

2017-03-14

Membrane protein function can be affected by the physical state of the lipid bilayer and specific lipid-protein interactions. For Na,K-ATPase, bilayer properties can modulate pump activity, and, as observed in crystal structures, several lipids are bound within the transmembrane domain. Furthermore, Na,K-ATPase activity depends on phosphatidylserine (PS) and cholesterol, which stabilize the protein, and polyunsaturated phosphatidylcholine (PC) or phosphatidylethanolamine (PE), known to stimulate Na,K-ATPase activity. Based on lipid structural specificity and kinetic mechanisms, specific interactions of both PS and PC/PE have been inferred. Nevertheless, specific binding sites have not been identified definitively. We address this question with native mass spectrometry (MS) and site-directed mutagenesis. Native MS shows directly that one molecule each of 18:0/18:1 PS and 18:0/20:4 PC can bind specifically to purified human Na,K-ATPase (α 1 β 1 ). By replacing lysine residues at proposed phospholipid-binding sites with glutamines, the two sites have been identified. Mutations in the cytoplasmic αL8-9 loop destabilize the protein but do not affect Na,K-ATPase activity, whereas mutations in transmembrane helices (TM), αTM2 and αTM4, abolish the stimulation of activity by 18:0/20:4 PC but do not affect stability. When these data are linked to crystal structures, the underlying mechanism of PS and PC/PE effects emerges. PS (and cholesterol) bind between αTM 8, 9, 10, near the FXYD subunit, and maintain topological integrity of the labile C terminus of the α subunit (site A). PC/PE binds between αTM2, 4, 6, and 9 and accelerates the rate-limiting E 1 P-E 2 P conformational transition (site B). We discuss the potential physiological implications.

Electronic structures at the interface between CuPc and black phosphorus

NASA Astrophysics Data System (ADS)

Wang, Can; Niu, Dongmei; Xie, Haipeng; Liu, Baoxing; Wang, Shitan; Zhu, Menglong; Gao, Yongli

2017-08-01

The electronic structure at the organic-inorganic semiconductor interface of π -conjugated copper phthalocyanine (CuPc) on a black phosphorus (BP) crystal surface is studied with photoemission spectroscopy and density functional theory calculations. From the photoemission spectra, we observe a shift of about 0.7 eV for the highest occupied molecular orbital, which originates from the transition of phase in the organic molecular thin film (from the interface phase to the bulk phase). On the other hand, we find 0.2 eV band bending at the CuPc/BP interface while the formation of an interface dipole is very small. According to our photoemission spectrum and theoretical simulation, we also define that the interaction between CuPc and BP is physisorption via van der Waals forces, rather than chemisorption. Our results provide a fundamental understanding of CuPc/BP interfacial interactions that could be important for future two-dimensional organic/inorganic heterostructure devices.

Distinguishing polymorphs of the semiconducting pigment copper phthalocyanine by solid-state NMR and Raman spectroscopy.

PubMed

Shaibat, Medhat A; Casabianca, Leah B; Siberio-Pérez, Diana Y; Matzger, Adam J; Ishii, Yoshitaka

2010-04-08

Cu(II)(phthalocyanine) (CuPc) is broadly utilized as an archetypal molecular semiconductor and is the most widely used blue printing pigment. CuPc crystallizes in six different forms; the chemical and physical properties are substantially modulated by its molecular packing among these polymorphs. Despite the growing importance of this system, spectroscopic identification of different polymorphs for CuPc has posed difficulties. This study presents the first example of spectroscopic distinction of alpha- and beta-forms of CuPc, the most widely used polymorphs, by solid-state NMR (SSNMR) and Raman spectroscopy. (13)C high-resolution SSNMR spectra of alpha- and beta-CuPc using very-fast magic angle spinning (VFMAS) at 20 kHz show that hyperfine shifts sensitively reflect polymorphs of CuPc. The experimental results were confirmed by ab initio chemical shift calculations. (13)C and (1)H SSNMR relaxation times of alpha- and beta-CuPc under VFMAS also showed marked differences, presumably because of the difference in electronic spin correlation times in the two forms. Raman spectroscopy also provided another reliable method of differentiation between the two polymorphs.

Ultralong copper phthalocyanine nanowires with new crystal structure and broad optical absorption.

PubMed

Wang, Hai; Mauthoor, Soumaya; Din, Salahud; Gardener, Jules A; Chang, Rio; Warner, Marc; Aeppli, Gabriel; McComb, David W; Ryan, Mary P; Wu, Wei; Fisher, Andrew J; Stoneham, Marshall; Heutz, Sandrine

2010-07-27

The development of molecular nanostructures plays a major role in emerging organic electronic applications, as it leads to improved performance and is compatible with our increasing need for miniaturization. In particular, nanowires have been obtained from solution or vapor phase and have displayed high conductivity or large interfacial areas in solar cells. In all cases however, the crystal structure remains as in films or bulk, and the exploitation of wires requires extensive postgrowth manipulation as their orientations are random. Here we report copper phthalocyanine (CuPc) nanowires with diameters of 10-100 nm, high directionality, and unprecedented aspect ratios. We demonstrate that they adopt a new crystal phase, designated eta-CuPc, where the molecules stack along the long axis. The resulting high electronic overlap along the centimeter length stacks achieved in our wires mediates antiferromagnetic couplings and broadens the optical absorption spectrum. The ability to fabricate ultralong, flexible metal phthalocyanine nanowires opens new possibilities for applications of these simple molecules.

Assessing the potential roles of silicon and germanium phthalocyanines in planar heterojunction organic photovoltaic devices and how pentafluoro phenoxylation can enhance π-π interactions and device performance.

PubMed

Lessard, Benoît H; White, Robin T; Al-Amar, Mohammad; Plint, Trevor; Castrucci, Jeffrey S; Josey, David S; Lu, Zheng-Hong; Bender, Timothy P

2015-03-11

In this study, we have assessed the potential application of dichloro silicon phthalocyanine (Cl2-SiPc) and dichloro germanium phthalocyanine (Cl2-GePc) in modern planar heterojunction organic photovoltaic (PHJ OPV) devices. We have determined that Cl2-SiPc can act as an electron donating material when paired with C60 and that Cl2-SiPc or Cl2-GePc can also act as an electron acceptor material when paired with pentacene. These two materials enabled the harvesting of triplet energy resulting from the singlet fission process in pentacene. However, contributions to the generation of photocurrent were observed for Cl2-SiPc with no evidence of photocurrent contribution from Cl2-GePc. The result of our initial assessment established the potential for the application of SiPc and GePc in PHJ OPV devices. Thereafter, bis(pentafluoro phenoxy) silicon phthalocyanine (F10-SiPc) and bis(pentafluoro phenoxy) germanium phthalocyanine (F10-GePc) were synthesized and characterized. During thermal processing, it was discovered that F10-SiPc and F10-GePc underwent a reaction forming small amounts of difluoro SiPc (F2-SiPc) and difluoro GePc (F2-GePc). This undesirable reaction could be circumvented for F10-SiPc but not for F10-GePc. Using single crystal X-ray diffraction, it was determined that F10-SiPc has significantly enhanced π-π interactions compared with that of Cl2-SiPc, which had little to none. Unoptimized PHJ OPV devices based on F10-SiPc were fabricated and directly compared to those constructed from Cl2-SiPc, and in all cases, PHJ OPV devices based on F10-SiPc had significantly improved device characteristics compared to Cl2-SiPc.

Enhanced Photocurrent of Transparent CuFeO2 Photocathodes by Self-Light-Harvesting Architecture.

PubMed

Oh, Yunjung; Yang, Wooseok; Kim, Jimin; Jeong, Sunho; Moon, Jooho

2017-04-26

Efficient sunlight-driven water-splitting devices can be achieved by using an optically and energetically well-matched pair of photoelectrodes in a tandem configuration. The key for maximizing the photoelectrochemical efficiency is the use of a highly transparent front photoelectrode with a band gap below 2.0 eV. Herein, we propose two-dimensional (2D) photonic crystal (PC) structures consisting of a CuFeO 2 -decorated microsphere monolayer, which serve as self-light-harvesting architectures allowing for amplified light absorption and high transparency. The photocurrent densities are evaluated for three CuFeO 2 2D PC-based photoelectrodes with microspheres of different sizes. The optical analysis confirmed the presence of a photonic stop band that generates slow light and at the same time amplifies the absorption of light. The 410 nm sized CuFeO 2 -decorated microsphere 2D PC photocathode shows an exceptionally high visible light transmittance of 76.4% and a relatively high photocurrent of 0.2 mA cm -2 at 0.6 V vs a reversible hydrogen electrode. The effect of the microsphere size on the carrier collection efficiency was analyzed by in situ conductive atomic force microscopy observation under illumination. Our novel synthetic method to produce self-light-harvesting nanostructures provides a promising approach for the effective use of solar energy by highly transparent photocathodes.

A cylindrical SPECT camera with de-centralized readout scheme

NASA Astrophysics Data System (ADS)

Habte, F.; Stenström, P.; Rillbert, A.; Bousselham, A.; Bohm, C.; Larsson, S. A.

2001-09-01

An optimized brain single photon emission computed tomograph (SPECT) camera is being designed at Stockholm University and Karolinska Hospital. The design goal is to achieve high sensitivity, high-count rate and high spatial resolution. The sensitivity is achieved by using a cylindrical crystal, which gives a closed geometry with large solid angles. A de-centralized readout scheme where only a local environment around the light excitation is readout supports high-count rates. The high resolution is achieved by using an optimized crystal configuration. A 12 mm crystal plus 12 mm light guide combination gave an intrinsic spatial resolution better than 3.5 mm (140 keV) in a prototype system. Simulations show that a modified configuration can improve this value. A cylindrical configuration with a rotating collimator significantly simplifies the mechanical design of the gantry. The data acquisition and control system uses early digitization and subsequent digital signal processing to extract timing and amplitude information, and monitors the position of the collimator. The readout system consists of 12 or more modules each based on programmable logic and a digital signal processor. The modules send data to a PC file server-reconstruction engine via a Firewire (IEEE-1394) network.

A Computational Study of Laminate Transparent Armor Impacted by FSP

DTIC Science & Technology

2009-06-01

of Hsieh et al [1], on targets consisting of 3mm PC-12mm PMMA-3mm PC impacted by 17-gr, 0.22 caliber fragment simulating projectile (FSP) at impact...results from the experiments of Hsieh et al [1], on targets consisting of 3mm PC-12mm PMMA-3mm PC impacted by 17-gr, 0.22 caliber fragment simulating...investigate several different analysis techniques to qualitatively determine their accuracy when compared with experiments of Hsieh et al [1]. The

Sensitive Detection of Protein and miRNA Cancer Biomarkers using Silicon-Based Photonic Crystals and A Resonance Coupling Laser Scanning Platform

PubMed Central

George, Sherine; Chaudhery, Vikram; Lu, Meng; Takagi, Miki; Amro, Nabil; Pokhriyal, Anusha; Tan, Yafang; Ferreira, Placid; Cunningham, Brian T.

2013-01-01

Enhancement of the fluorescent output of surface-based fluorescence assays by performing them upon nanostructured photonic crystal (PC) surfaces has been demonstrated to increase signal intensities by >8000×. Using the multiplicative effects of optical resonant coupling to the PC in increasing the electric field intensity experienced by fluorescent labels (“enhanced excitation”) and the spatially biased funneling of fluorophore emissions through coupling to PC resonances (“enhanced extraction”), PC enhanced fluorescence (PCEF) can be adapted to reduce the limits of detection of disease biomarker assays, and to reduce the size and cost of high sensitivity detection instrumentation. In this work, we demonstrate the first silicon-based PCEF detection platform for multiplexed biomarker assay. The sensor in this platform is a silicon-based PC structure, comprised of a SiO2 grating that is overcoated with a thin film of high refractive index TiO2 and is produced in a semiconductor foundry for low cost, uniform, and reproducible manufacturing. The compact detection instrument that completes this platform was designed to efficiently couples fluorescence excitation from a semiconductor laser to the resonant optical modes of the PC, resulting in elevated electric field strength that is highly concentrated within the region <100 nm from the PC surface. This instrument utilizes a cylindrically focused line to scan a microarray in <1 minute. To demonstrate the capabilities of this sensor-detector platform, microspot fluorescent sandwich immunoassays using secondary antibodies labeled with Cy5 for two cancer biomarkers (TNF-α and IL-3) were performed. Biomarkers were detected at concentrations as low as 0.1 pM. In a fluorescent microarray for detection of a breast cancer miRNA biomarker miR-21, the miRNA was detectable at a concentration of 0.6 pM. PMID:23963502

Band gap in tubular pillar phononic crystal plate.

PubMed

Shu, Fengfeng; Liu, Yongshun; Wu, Junfeng; Wu, Yihui

2016-09-01

In this paper, a phononic crystal (PC) plate with tubular pillars is presented and investigated. The band structures and mode displacement profiles are calculated by using finite element method. The result shows that a complete band gap opens when the ratio of the pillar height to the plate thickness is about 1.6. However, for classic cylinder pillar structures, a band gap opens when the ratio is equal or greater than 3. A tubular pillar design with a void room in it enhances acoustic multiple scattering and gives rise to the opening of the band gap. In order to verify it, a PC structure with double tubular pillars different in size (one within the other) is introduced and a more than 2times band gap enlargement is observed. Furthermore, the coupling between the resonant mode and the plate mode around the band gap is characterized, as well as the effect of the geometrical parameters on the band gap. The behavior of such structure could be utilized to design a pillar PC with stronger structural stability and to enlarge band gaps. Copyright © 2016 Elsevier B.V. All rights reserved.

Microscopy and Chemical Inversing Techniques to Determine the Photonic Crystal Structure of Iridescent Beetle Scales in the Cerambycidae Family

NASA Astrophysics Data System (ADS)

Richey, Lauren; Gardner, John; Standing, Michael; Jorgensen, Matthew; Bartl, Michael

2010-10-01

Photonic crystals (PCs) are periodic structures that manipulate electromagnetic waves by defining allowed and forbidden frequency bands known as photonic band gaps. Despite production of PC structures operating at infrared wavelengths, visible counterparts are difficult to fabricate because periodicities must satisfy the diffraction criteria. As part of an ongoing search for naturally occurring PCs [1], a three-dimensional array of nanoscopic spheres in the iridescent scales of the Cerambycidae insects A. elegans and G. celestis has been found. Such arrays are similar to opal gemstones and self-assembled colloidal spheres which can be chemically inverted to create a lattice-like PC. Through a chemical replication process [2], scanning electron microscopy analysis, sequential focused ion beam slicing and three-dimensional modeling, we analyzed the structural arrangement of the nanoscopic spheres. The study of naturally occurring structures and their inversing techniques into PCs allows for diversity in optical PC fabrication. [1] J.W. Galusha et al., Phys. Rev. E 77 (2008) 050904. [2] J.W. Galusha et al., J. Mater. Chem. 20 (2010) 1277.

Terahertz Sensor Using Photonic Crystal Cavity and Resonant Tunneling Diodes

NASA Astrophysics Data System (ADS)

Okamoto, Kazuma; Tsuruda, Kazuisao; Diebold, Sebastian; Hisatake, Shintaro; Fujita, Masayuki; Nagatsuma, Tadao

2017-09-01

In this paper, we report on a terahertz (THz) sensing system. Compared to previously reported systems, it has increased system sensitivity and reduced size. Both are achieved by using a photonic crystal (PC) cavity as a resonator and compact resonant tunneling diodes (RTDs) as signal source and as detector. The measured quality factor of the PC cavity is higher than 10,000, and its resonant frequency is 318 GHz. To demonstrate the operation of the refractive index sensing system, dielectric tapes of various thicknesses are attached to the PC cavity and the change in the resonator's refractive index is measured. The figure of merit of refractive index sensing using the developed system is one order higher than that of previous studies, which used metallic metamaterial resonators. The frequency of the RTD-based source can be swept from 316 to 321 GHz by varying the RTD direct current voltage. This effect is used to realize a compact frequency tunable signal source. Measurements using a commercial signal source and detector are carried out to verify the accuracy of the data obtained using RTDs as a signal source and as a detector.

Meso-size Effect from Self-assembled Carbon Structures and Their Device Applications

DTIC Science & Technology

2013-08-23

electrical photoresponse from pentacene 1D disks and 2D wires, and 3) dramatic increase of solubility in water of zinc phthalocyanine (ZnPc) nanowires...Hong, M.; Son, M.; Choi, H. C.* “Crystal Plane-Dependent Photoluminescence Activity of Pentacene 1D Wire and 2D Disk Crystals.” Angew. Chem. Int...Ed. 2013, 52, 5997-6001. [7] Park, J. E.; Hong, M.; Son, M.; Choi, H. C.* “Crystal Plane-Dependent Photoluminescence Activity of Pentacene 1D Wire

Organic Light Emitting Diodes with Opal Photonic Crystal Layer and Carbon Nanotube Anode

NASA Astrophysics Data System (ADS)

Ovalle Robles, Raquel; Del Rocio Nava, Maria; Williams, Christopher; Zhang, Mei; Fang, Shaoli; Lee, Sergey; Baughman, Ray; Zakhidov, Anvar

2007-03-01

We report electroluminescence intensity and spectral changes in light emission from organic light emitting diode (OLEDs) structures, which have thin transparent films of opal photonic crystal (PC). The anode in such PC-OLED is laminated on opal layer from free standing optically transparent multiwall carbon nanotubes (T-CNT) sheets made by dry spinning from CVD grown forests. Silica and polystyrene opal films were grown on glass substrates by vertical sedimentation in colloids in thermal baths and the particle size of opal spheres ranges from 300 nm to 450 nm. The use of T-CNTs, (coated by PEDOT-PSS to avoid shorting) as hole injector, allows to eliminate the use of vacuum deposition of metals and permits to achieve tunneling hole injection regime from CNT tips into Alq^3 emission layer

Label-free in vitro prostate cancer cell detection via photonic-crystal biosensor

NASA Astrophysics Data System (ADS)

DeLuna, Frank; Ding, XiaoFei; Sagredo, Ismael; Bustamante, Gilbert; Sun, Lu-Zhe; Ye, Jing Yong

2018-02-01

Prostate-specific antigen (PSA) biomarker assays are the current clinical method for mass screening of prostate cancer. However, high false-positive rates are often reported due to PSA's low specificity, leading to an urgent need for the development of a more specific detection system independent of PSA levels. In our previous research, we demonstrated the feasibility of using cellular refractive indices (RI) as a unique contrast parameter to accomplish label-free detection of prostate cancer cells via variance testing, but were unable to determine if a specific cell was cancerous or noncancerous. In this paper, we report the use of our Photonic-Crystal biosensor in a Total-Internal-Reflection (PC-TIR) configuration to construct a label-free imaging system, which allows for the detection of individual prostate cancer cells utilizing cellular RI as the only contrast parameter. Noncancerous prostate (BPH-1) cells and prostate cancer (PC-3) cells were mixed at varied ratios and measured concurrently. Additionally, we isolated and induced PC-3 cells to undergo epithelial-mesenchymal transition (EMT) by exposing these cells to soluble factors such as TGF-β1. The biophysical characteristics of the cellular RI were quantified extensively in comparison to non-induced PC-3 cells as well as BPH-1 cells. EMT is a crucial mechanism for the invasion and metastasis of epithelial tumors characterized by the loss of cell-cell adhesion and increased cell mobility. Our study shows promising clinical potential in utilizing the PC-TIR biosensor imaging system to not only detect prostate cancer cells, but also evaluate prostate cancer progression.

Training HBCU Faculty and Students in Prostate Cancer (PC) Research: Signal Transduction and Receptor-Inhibitor Interactions in the Progress of PC

DTIC Science & Technology

2008-03-01

thiocinnamide, and 4-[(3-bromophenyl) amino ]-6- propionylamidoquinazoline have been completed. We continue to crystallize samples of tyrosine kinase...been developed last year identify the geometric relationship between structural features of a set of molecules known to act as tyrosine kinase...L. Klein Stevens, “A Crystallographic Study of ErbB2 Tyrosine Kinase Inhibitors”, 230th American Chemical Society National Meeting, Washington, DC

CdTe-based Light-Controllable Frequency-Selective Photonic Crystal Switch for Millimeter Waves

DTIC Science & Technology

2011-09-01

position (magenta curves with circular points which correspond to different light pulses) 23 Fig. 11.3. (a) Phase of transmission wave (in...11.4. Transmission spectra of plastic-air PC with CdTe-coated triple -quartz-wafer insertion of the kind ‘6t-qvqvqs-6t’ (computed yellow and measured...experimental requirements of matching the frequency band of VNA facility (f = 75–110 GHz), PC structures with triple -wafer insertion layers

Evaluation of a novel label-free photonic-crystal biosensor imaging system for the detection of prostate cancer cells

NASA Astrophysics Data System (ADS)

DeLuna, Frank; Ding, XiaoFie; Sun, Lu-Zhe; Ye, Jing Yong

2017-02-01

Biomarker screening for prostate-specific antigen (PSA) is the current clinical standard for detection of prostate cancer. However this method has shown many limitations, mainly in its specificity, which can lead to a high false positive rate. Thus, there is a growing need in developing a more specific detection system for prostate cancer. Using a Photonic- Crystal-based biosensor in a Total-Internal-Reflection (PC-TIR) configuration, we demonstrate the use of refractive index (RI) to accomplish label-free detection of prostate cancer cells against non-cancerous prostate epithelial cells. The PC-TIR biosensor possesses an open microcavity, which in contrast to traditional closed microcavities, allows for easier access of analyte molecules or cells to interact with its sensing surface. In this study, an imaging system was designed using the PC-TIR biosensor to quantify cell RI as the contrast parameter for prostate cancer detection. Non-cancerous BPH-1 prostate epithelial cells and prostate cancer PC-3 cells were placed on a single biosensor and measured concurrently. Recorded image data was then analyzed through a home-built MatLab program. Results demonstrate that RI is a suitable variable for differentiation between prostate cancer cells and non-cancerous prostate epithelial cells. Our study shows clinical potential in utilizing RI test for the detection of prostate cancer.

Pristine fullerenes mixed by vacuum-free solution process: Efficient electron transport layer for planar perovskite solar cells

NASA Astrophysics Data System (ADS)

Dai, Si-Min; Tian, Han-Rui; Zhang, Mei-Lin; Xing, Zhou; Wang, Lu-Yao; Wang, Xin; Wang, Tan; Deng, Lin-Long; Xie, Su-Yuan; Huang, Rong-Bin; Zheng, Lan-Sun

2017-01-01

Discovery of organic-inorganic hybrid perovskites ignites the dream of next-generation solar cells fabricated by low-cost solution processing. To date, fullerene derivative [6,6]-phenyl-C61- butyric acid methyl ester (PC61BM), is the most prevalently used electron transport layer for high efficiency p-i-n planar heterojunction perovskite solar cells. Compared with PC61BM, pristine fullerenes, such as C60 and C70, have shown superiority of higher electron mobility and much lower costs. Due to the poor solubility and strong tendency to crystallize for pristine fullerenes in solution process, it is still a challenge to deposit compact and continuous film of pristine fullerenes for p-i-n type perovskite solar cells by solution processing. Herein, solution processed pristine fullerenes (C60 and C70) were used as electron transport layers to replace PC61BM in perovskite solar cells with high performance and enhanced stability. Power conversion efficiency of 14.04% was obtained by using mixture of C60 and C70 as electron transport layer, which is comparable to that of PC61BM based device (13.74%). We demonstrated that the strong tendency of pristine fullerenes to crystallize during solvent removal can be largely mitigated by mixing different kinds of pristine fullerenes. These findings implicate pristine fullerenes as promising electron transport layers for high performance perovskite solar cells.

Morphological, structural and optical properties of MEH-PPV: PC70BM nanocomposite film

NASA Astrophysics Data System (ADS)

Mhamdi, Asya; Sweii, Fatma ben Slama; Saidi, Hamza; Saidi, Faouzi; Bouazizi, Abdelaziz

2018-05-01

In this report, the influence of annealing temperature and spin coating speed on the structural and morphological properties of a blend of poly (2-methoxy-5-(2-ethyl-oxy)-p-phenylene-vinylene) (MEH-PPV) and [6-6]-phenyl-C71-butyric acid methyl ester (PC70BM) layer has been investigated. The photoactive layer (MEH-PPV: PC70BM) was deposited on ZnO film deposited on top of indium tin oxide (ITO) substrate by spin-coating. The effect of spin coating speed via atomic force microscope (AFM) leads to conclude that high speed is favorable for a good homogeneity of the film surface and good aggregates dispersion. The optimized structure was studied by varying the annealing temperatures using X-ray diffraction (XRD). The XRD analysis indicates that annealing treatment promoted the ordered aggregation and crystallization of MEH-PPV: PC70BM films. Indeed, the blend ratio effect on the optical properties of MEH-PPV: PC70BM thin film was investigated. While, the effect of incorporation of PC70BM on the optical properties was studied using UV-Vis and photoluminescence (PL) measurement. We conclude that MEH-PPV: PC70BM (1:3) film leads to high charge transfer rate.

Distinguishing Polymorphs of the Semiconducting Pigment Copper Phthalocyanine by Solid-state NMR and Raman Spectroscopy

PubMed Central

Shaibat, Medhat A.; Casabianca, Leah B.; Siberio-Pérez, Diana Y.; Matzger, Adam J; Ishii, Yoshitaka

2010-01-01

Cu(II)(phthalocyanine) (CuPc) is broadly utilized as an archetypal molecular semiconductor and is the most widely used blue printing pigment. CuPc crystallizes in six different forms; the chemical and physical properties are substantially modulated by its molecular packing among these polymorphs. Despite the growing importance of this system, spectroscopic identification of different polymorphs for CuPc has posed difficulties. This study presents the first example of spectroscopic distinction of α- and β-forms of CuPc, the most widely used polymorphs, by solid-state NMR (SSNMR) and Raman spectroscopy. 13C high-resolution SSNMR spectra of α- and β-CuPc using very-fast magic angle spinning (VFMAS) at 20 kHz show that hyperfine shifts sensitively reflect polymorphs of CuPc. The experimental results were confirmed by ab initio chemical shift calculations. 13C and 1H SSNMR relaxation times of α- and β-CuPc under VFMAS also showed marked differences, presumably because of the difference in electronic spin correlation times in the two forms. Raman spectroscopy also provided another reliable method of differentiation between the two polymorphs. PMID:20225842

Ring-patterned plasmonic photonic crystal thermal light source for miniaturized near-infrared spectrometers

NASA Astrophysics Data System (ADS)

Labib, Shady R.; Elsayed, Ahmed A.; Sabry, Yasser M.; Khalil, Diaa

2018-02-01

There is a growing number of spectroscopy applications in the near-infrared (NIR) range including gas sensing, food analysis, pharmaceutical and industrial applications that requires highly efficient, more compact and low-cost miniaturized spectrometers. One of the key components for such systems is the wideband light source that can be fabricated using Silicon technology and hence integrated with other components on the same chip. In this work, we report a ring-patterned plasmonic photonic crystal (PC) thermal light source for miniaturized near-infrared spectrometers. The design is based on silicon and tuned to achieve wavelength selectivity in the emitted spectrum. The design is optimized by using Rigorous Coupled-Wave Analysis (RCWA) simulation, which is used to compute the power reflectance and transmittance that are used to predict the emissivity of the structure. The design consists of a PC of silicon rings coated with platinum. The period of the structure is about 2 μm and the silicon is highly-doped with n-type doping level in the order of 1019-1020 cm-3 to enhance the free-carrier absorption. The ring etching depth, diameter and shell thickness are optimized to increase its emissivity within a specific wavelength range of interest. The simulation results show an emissivity exceeding 0.9 in the NIR range up to 2.5 μm, while the emissivity is decreased significantly for longer wavelengths suppressing the emission out of the range of interest, and hence increasing the efficiency for the source. The reported results open the door for black body radiation engineering in integrated silicon sources for spectrometer miniaturization.

IR Sensor Synchronizing Active Shutter Glasses for 3D HDTV with Flexible Liquid Crystal Lenses

PubMed Central

Han, Jeong In

2013-01-01

IR sensor synchronizing active shutter glasses for three-dimensional high definition television (3D HDTV) were developed using a flexible liquid crystal (FLC) lens. The FLC lens was made on a polycarbonate (PC) substrate using conventional liquid crystal display (LCD) processes. The flexible liquid crystal lens displayed a maximum transmission of 32% and total response time of 2.56 ms. The transmittance, the contrast ratio and the response time of the flexible liquid crystal lens were superior to those of glass liquid crystal lenses. Microcontroller unit and drivers were developed as part of a reception module with power supply for the IR sensor synchronizing active shutter glasses with the flexible liquid crystal lens prototypes. IR sensor synchronizing active shutter glasses for 3D HDTV with flexible liquid crystal lenses produced excellent 3D images viewing characteristics.

Enhanced sensitivity to near-infrared with high fill factor in small molecular organic solar cells

NASA Astrophysics Data System (ADS)

Shim, Hyun-Sub; Kim, Hyo Jung; Kim, Ji Whan; Kim, Sei-Yong; Jeong, Won-Ik; Kim, Tae-Min; Kim, Jang-Joo

2012-09-01

High efficiency near-infrared (NIR) absorbing solar cells based on lead phthalocyanine (PbPc) are reported using copper iodide (CuI) as a templating layer to control the crystal structure of PbPc. Devices with CuI inserted between the ITO and PbPc layers exhibit a two times enhancement of the JSC compared to the case in the absence of the CuI layer. This is due to the increase of crystallinity in the molecules grown on the CuI templating layer, which is investigated via an x-ray diffraction study. Moreover, fill factor is also enhanced to 0.63 from 0.57 due to low series resistance although the additional CuI layer is inserted between the ITO and the PbPc layer. As a result, the corrected power conversion efficiency of 2.5% was obtained, which is the highest one reported up to now among the PbPc based solar cells.

Ultracompact photonic crystal polarization beam splitter based on multimode interference.

PubMed

Lu, Ming-Feng; Liao, Shan-Mei; Huang, Yang-Tung

2010-02-01

We propose a theoretical design for a compact photonic crystal (PC) polarization beam splitter (PBS) based on the multimode interference (MMI) effect. The size of a conventional MMI device designed by the self-imaging principle is not compact enough; therefore, we design a compact PC PBS based on the difference of the interference effect between TE and TM modes. Within the MMI coupler, the dependence of interference of modes on propagation distance is weak for a TE wave and strong for a TM wave; as a result, the length of the MMI section can be only seven lattice constants. Simulation results show that the insertion losses are 0.32 and 0.89 dB, and the extinction ratios are 14.4 and 17.5 dB for Port 1 (TE mode) and Port 2 (TM mode), respectively.

Bistable four-wave mixing response in a semiconductor quantum dot coupled to a photonic crystal nanocavity.

PubMed

Li, Jian-Bo; Xiao, Si; Liang, Shan; He, Meng-Dong; Luo, Jian-Hua; Kim, Nam-Chol; Chen, Li-Qun

2017-10-16

We perform a theoretical study of the bistable four-wave mixing (FWM) response in a coupled system comprised of a semiconductor quantum dot (SQD) and a photonic crystal (PC) nanocavity in which the SQD is embedded. It is shown that the shape of the FWM spectrum can switch among single-peaked, double-peaked, triple-peaked, and four-peaked arising from the vacuum Rabi splitting and the exciton-nanocavity coupling. Especially, we map out bistability phase diagrams within a parameter subspace of the system, and find that it is easy to turn on or off the bistable FWM response by only adjusting the excitation frequency or the pumping intensity. Our results offer a feasible means for measuring the SQD-PC nanocavity coupling strength and open a new avenue to design optical switches and memories.

Bench-Scale Development of a Hot Carbonate Absorption Process with Crystallization-Enabled High-Pressure Stripping for Post-Combustion CO{sub 2} Capture

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

Lu, Yongqi; DeVries, Nicholas; Ruhter, David

A novel Hot Carbonate Absorption Process with Crystallization-Enabled High-Pressure Stripping (Hot-CAP) has been developed by the University of Illinois at Urbana-Champaign and Carbon Capture Scientific, LLC in this three-year, bench-scale project. The Hot-CAP features a concentrated carbonate solution (e.g., K{sub 2}CO{sub 3}) for CO{sub 2} absorption and a bicarbonate slurry (e.g., KHCO{sub 3}) for high-pressure CO{sub 2} stripping to overcome the energy use and other disadvantages associated with the benchmark monoethanolamine (MEA) process. The project was aimed at performing laboratory- and bench-scale experiments to prove its technical feasibility and generate process engineering and scale-up data, and conducting a techno-economic analysismore » (TEA) to demonstrate its energy use and cost competitiveness over MEA. To meet project goals and objectives, a combination of experimental, modeling, process simulation, and economic analysis studies were applied. Carefully designed and intensive experiments were conducted to measure thermodynamic and reaction engineering data relevant to four major unit operations in the Hot-CAP (i.e., CO{sub 2} absorption, CO{sub 2} stripping, bicarbonate crystallization, and sulfate reclamation). The rate promoters that could accelerate the CO{sub 2} absorption rate into the potassium carbonate/bicarbonate (PCB) solution to a level greater than that into the 5 M MEA solution were identified, and the superior performance of CO{sub 2} absorption into PCB was demonstrated in a bench-scale packed-bed column. Kinetic data on bicarbonate crystallization were developed and applied for crystallizer design and sizing. Parametric testing of high-pressure CO{sub 2} stripping with concentrated bicarbonate-dominant slurries at high temperatures ({>=}140{degrees}C) in a bench-scale stripping column demonstrated lower heat use than with MEA. The feasibility of a modified process for combining SO{sub 2} removal with CO{sub 2} capture was preliminarily demonstrated. In addition to the experimental studies, the technical challenges pertinent to fouling of slurry-handling equipment and the design of the crystallizer and stripper were addressed through consultation with vendors and engineering analyses. A process flow diagram of the Hot-CAP was then developed and a TEA was performed to compare the energy use and cost performance of a nominal 550-MWe subcritical pulverized coal (PC)-fired power plant without CO{sub 2} capture (DOE/NETL Case 9) with the benchmark MEA-based post-combustion CO{sub 2} capture (PCC; DOE/NETL Case 10) and the Hot-CAP-based PCC. The results revealed that the net power produced in the PC + Hot-CAP is 609 MWe, greater than the PC + MEA (550 MWe). The 20-year levelized cost of electricity (LCOE) for the PC + Hot-CAP, including CO{sub 2} transportation and storage, is 120.3 mills/kWh, a 60% increase over the base PC plant without CO{sub 2} capture. The LCOE increase for the Hot-CAP is 29% lower than that for MEA. TEA results demonstrated that the Hot-CAP is energy-efficient and cost-effective compared with the benchmark MEA process.« less

Structural heterogeneity leads to functional homogeneity in A. marina phycocyanin.

PubMed

Bar-Zvi, Shira; Lahav, Avital; Harris, Dvir; Niedzwiedzki, Dariusz M; Blankenship, Robert E; Adir, Noam

2018-07-01

The major light harvesting antenna in all cyanobacterial species is the phycobilisome (PBS). The smallest PBS identified to date is that of Acaryochloris marina (A. marina), composed of a single four-hexamer rod. We have determined the crystal structure of phycocyanin (AmPC), the major component of the A. marina PBS (AmPBS) to 2.1 Å. The basic unit of the AmPC is a heterodimer of two related subunits (α and β), and we show that the asymmetric unit contains a superposition of two α and two β isoforms, the products of the simultaneous expression of different genes. This is the first time to our knowledge that isolated proteins crystallized with such identifiable heterogeneity. We believe that the presence of the different isoforms allows the AmPBS to have a significant bathochromic shift in its fluorescence emission spectrum, allowing, in the total absence of allophycocyanin, a better overlap with absorption of the chlorophyll d-containing reaction centers. We show that this bathochromic shift exists in intact AmPBS as well as in its disassembled components, thus suggesting that AmPC can efficiently serve as the AmPBS terminal emitter. Copyright © 2018 Elsevier B.V. All rights reserved.

Correlation and the mechanism of lithium ion diffusion with the crystal structure of Li7La3Zr2O12 revealed by an internal friction technique.

PubMed

Wang, X P; Gao, Y X; Xia, Y P; Zhuang, Z; Zhang, T; Fang, Q F

2014-04-21

The correlation and transport mechanism of lithium ions with the crystal structure of a fast lithium ion conductor Li7La3Zr2O12 are mainly investigated by internal friction (IF) and AC impedance spectroscopy techniques. Compared with the poor conductivity of tetragonal Li7La3Zr2O12, the Al stabilized cubic phase exhibits a good ionic conductivity that can be up to 1.9 × 10(-4) S cm(-1) at room temperature, which can be ascribed to the disordered distribution of lithium ions in the cubic phase. A well-pronounced relaxation IF peak (labeled as peak PC) is observed in the cubic phase while a very weak IF peak (labeled as PT) is observed in the tetragonal phase, further evidencing the difference in lithium ion migration in the two phases. Peak PC can be decomposed into two sub-peaks with the activation energy and the pre-exponential factor of relaxation time being E1 = 0.41 eV and τ01 = 1.2 × 10(-14) s for the lower temperature peak PC1 and E2 = 0.35 eV and τ02 = 1.9 × 10(-15) s for the higher temperature PC2 peak, respectively. Based on the crystalline structure of a cubic garnet-type Li7La3Zr2O12 compound, an atomistic mechanism of lithium ion diffusion via vacancies is suggested, i.e. 48g(96h) ↔ 48g(96h) for peak PC1 and 48g(96h) ↔ 24d for peak PC2, respectively. The weak PT peak in the tetragonal phase is preliminarily interpreted as due to the short jump process among neighboring octahedral sites and vacant tetrahedral sites.

Selective nucleation of iron phthalocyanine crystals on micro-structured copper iodide.

PubMed

Rochford, Luke A; Ramadan, Alexandra J; Heutz, Sandrine; Jones, Tim S

2014-12-14

Morphological and structural control of organic semiconductors through structural templating is an efficient route by which to tune their physical properties. The preparation and characterisation of iron phthalocyanine (FePc)-copper iodide (CuI) bilayers at elevated substrate temperatures is presented. Thin CuI(111) layers are prepared which are composed of isolated islands rather than continuous films previously employed in device structures. Nucleation in the early stages of FePc growth is observed at the edges of islands rather than on the top (111) faces with the use of field emission scanning electron microscopy (FE-SEM). Structural measurements show two distinct polymorphs of FePc, with CuI islands edges nucleating high aspect ratio FePc crystallites with modified intermolecular spacing. By combining high substrate temperature growth and micro-structuring of the templating CuI(111) layer structural and morphological control of the organic film is demonstrated.

A Method for Identifying Small-Molecule Aggregators Using Photonic Crystal Biosensor Microplates

PubMed Central

Chan, Leo L.; Lidstone, Erich A.; Finch, Kristin E.; Heeres, James T.; Hergenrother, Paul J.; Cunningham, Brian T.

2010-01-01

Small molecules identified through high-throughput screens are an essential element in pharmaceutical discovery programs. It is now recognized that a substantial fraction of small molecules exhibit aggregating behavior leading to false positive results in many screening assays, typically due to nonspecific attachment to target proteins. Therefore, the ability to efficiently identify compounds within a screening library that aggregate can streamline the screening process by eliminating unsuitable molecules from further consideration. In this work, we show that photonic crystal (PC) optical biosensor microplate technology can be used to identify and quantify small-molecule aggregation. A group of aggregators and nonaggregators were tested using the PC technology, and measurements were compared with those gathered by three alternative methods: dynamic light scattering (DLS), an α-chymotrypsin colorimetric assay, and scanning electron microscopy (SEM). The PC biosensor measurements of aggregation were confirmed by visual observation using SEM, and were in general agreement with the α-chymotrypsin assay. DLS measurements, in contrast, demonstrated inconsistent readings for many compounds that are found to form aggregates in shapes, very different from the classical spherical particles assumed in DLS modeling. As a label-free detection method, the PC biosensor aggregation assay is simple to implement and provides a quantitative direct measurement of the mass density of material adsorbed to the transducer surface, whereas the microplate-based sensor format enables compatibility with high-throughput automated liquid-handling methods used in pharmaceutical screening. PMID:20930952

Optical characteristics of a one-dimensional photonic crystal with an additional regular layer

NASA Astrophysics Data System (ADS)

Tolmachev, V. A.; Baldycheva, A. V.; Krutkova, E. Yu.; Perova, T. S.; Berwick, K.

2009-06-01

In this paper, the forbidden Photonic Band Gaps (PBGs) of a one-dimensional Photonic Crystal (1D PC) with additional regular layer, t for the constant value of the lattice constant A and at normal incident of light beam were investigated. The additional regular layer was formed from both sides of the high-refractive index layer H. The gap map approach and the Transfer Matrix Method were used for numerical analysis of this structure. The limitation of filling fraction values caused by the presence of t-layer was taking into account during calculations of the Stop-Band (SB) regions for threecomponent PC. The red shift of SBs was observed at the introduction of t-layer to conventional two-component 1D PC with optical contrast of N=3.42/1. The blue edge of the first PBG occupied the intermediate position between the blue edges of SBs regions of conventional PCs with different optical contrast N. This gives the opportunity of tuning the optical contrast of PC by introduction of the additional layer, rather than using the filler, as well as fine tuning of the SB edge. The influence of the number of periods m and the optical contrast N on the properties of SBs was also investigated. The effect of the PBG disappearance in the gap map and in the regions of the PBGs of high order was revealed at certain parameters of the additional layer.

Hydrogen and deuterium in the local interstellar medium

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

Murthy, J.N.

1987-01-01

This work reports on the results of a series of IUE observations of interstellar HI and DI Ly..cap alpha.. absorption against the chromospheric Ly..cap alpha.. emission of the nearby late-type stars ..cap alpha.. Cen B(1.3 pc), epsilon Eri (3.3 pc), Procyon (3.5 pc), Altair (5.1 pc), Capella (13.2 pc), and HR 1099 (33 pc). The density, velocity dispersion, and bulk velocity of the neutral hydrogen along the line of sight to each of these stars was derived. Lower limits were placed on the deuterium-to-hydrogen (D/H) ratio towards the same stars. These IUE results are generally consistent with previous observations ofmore » the same stars with the Copernicus satellite showing that this modeling procedure is independent of stellar variations over a period of several years. The HI absorption profile towards Altair shows a broad saturated core and steep line wings, consistent with a multicomponent interstellar medium in that direction. The bulk velocities towards the other stars are consistent with a bulk flow from the approximate direction of the galactic center but do show local variations from a uniform flow, possibly indicating a complicated velocity structure even in the solar neighborhood. Interstellar deuterium is detected towards every star except Altair and the derived values for the D/H ratio are consistent with those previously found with Copernicus.« less

Band structure of comb-like photonic crystals containing meta-materials

NASA Astrophysics Data System (ADS)

Weng, Yi; Wang, Zhi-Guo; Chen, Hong

2007-09-01

We study the transmission properties and band structure of comb-like photonic crystals (PC) with backbones constructed of meta-materials (negative-index materials) within the frame of the interface response theory. The result shows the existence of a special band gap at low frequency. This gap differs from the Bragg gaps in that it is insensitive to the geometrical scaling and disorder. In comparison with the zero-average-index gap in one-dimensional PC made of alternating positive- and negative-index materials, the gap is obviously deeper and broader, given the same system parameters. In addition, the behavior of its gap-edges is also different. One gap-edge is decided by the average permittivity whereas the other is only subject to the changing of the permeability of the backbone. Due to this asymmetry of the two gap-edges, the broadening of the gap could be realized with much freedom and facility.

Nano-lithographically fabricated titanium dioxide based visible frequency three dimensional gap photonic crystal.

PubMed

Subramania, Ganapathi; Lee, Yun-Ju; Brener, Igal; Luk, Ting-Shan; Clem, Paul G

2007-10-01

Photonic crystals (PC) have emerged as important types of structures for light manipulation. Ultimate control of light is possible by creating PCs with a complete three dimensional (3D) gap [1, 2]. This has proven to be a considerable challenge in the visible and ultraviolet frequencies mainly due to complications in integrating transparent, high refractive index (n) materials with fabrication techniques to create ~ 100nm features with long range translational order. In this letter, we demonstrate a nano-lithography approach based on a multilevel electron beam direct write and physical vapor deposition, to fabricate four-layer titania woodpile PCs that potentially exhibit complete 3D gap at visible wavelengths. We achieved a short wavelength bandedge of 525nm with a 300nm lattice constant PC. Due to the nanoscale precision and capability for defect control, the nanolithography approach represents an important step toward novel visible photonic devices for lighting, lasers, sensing and biophotonics.

Observations of cavity polaritons in one-dimensional photonic crystals containing a liquid-crystalline semiconductor based on perylene bisimide units

NASA Astrophysics Data System (ADS)

Sakata, T.; Suzuki, M.; Yamamoto, T.; Nakanishi, S.; Funahashi, M.; Tsurumachi, N.

2017-10-01

We investigated the optical transmission properties of one-dimensional photonic crystal (1D-PC) microcavity structures containing the liquid-crystalline (LC) perylene tetracarboxylic bisimide (PTCBI) derivative. We fabricated the microcavity structures for this study by two different methods and observed the cavity polaritons successfully in both samples. For one sample, since the PTCBI molecules were aligned in the cavity layer of the 1D-PC by utilizing a friction transfer method, vacuum Rabi splitting energy was strongly dependent on the polarization of the incident light produced by the peculiar optical features of the LC organic semiconductor. For the other sample, we did not utilize the friction transfer method and did not observe such polarization dependence. However, we did observe a relatively large Rabi splitting energy of 187 meV, probably due to the improvement of optical confinement effect.

Patterned Colloidal Photonic Crystals.

PubMed

Hou, Jue; Li, Mingzhu; Song, Yanlin

2018-03-01

Colloidal photonic crystals (PCs) have been well developed because they are easy to prepare, cost-effective, and versatile with regards to modification and functionalization. Patterned colloidal PCs contribute a novel approach to constructing high-performance PC devices with unique structures and specific functions. In this review, an overview of the strategies for fabricating patterned colloidal PCs, including patterned substrate-induced assembly, inkjet printing, and selective immobilization and modification, is presented. The advantages of patterned PC devices are also discussed in detail, for example, improved detection sensitivity and response speed of the sensors, control over the flow direction and wicking rate of microfluidic channels, recognition of cross-reactive molecules through an array-patterned microchip, fabrication of display devices with tunable patterns, well-arranged RGB units, and wide viewing-angles, and the ability to construct anti-counterfeiting devices with different security strategies. Finally, the perspective of future developments and challenges is presented. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Pressure-controlled terahertz filter based on 1D photonic crystal with a defective semiconductor

NASA Astrophysics Data System (ADS)

Qinwen, XUE; Xiaohua, WANG; Chenglin, LIU; Youwen, LIU

2018-03-01

The tunable terahertz (THz) filter has been designed and studied, which is composed of 1D photonic crystal (PC) containing a defect layer of semiconductor GaAs. The analytical solution of 1D defective PC (1DDPC) is deduced based on the transfer matrix method, and the electromagnetic plane wave numerical simulation of this 1DDPC is performed by using the finite element method. The calculated and simulated results have confirmed that the filtering transmittance of this 1DDPC in symmetric structure of air/(Si/SiO2) N /GaAs/(SiO2/Si) N /air is far higher than in asymmetric structure of air/(Si/SiO2) N /GaAs/(Si/SiO2) N /air, where the filtering frequency can be tuned by the external pressure. It can provide a feasible route to design the external pressure-controlled THz filter based on 1DPC with a defective semiconductor.

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

Zhang, Dongbo; Zhao, Jinfeng, E-mail: jinfeng.zhao@tongji.edu.cn; Li, Libing

In this work, we applied a robust and fully air-coupled method to investigate the propagation of the lowest-order antisymmetric Lamb (A{sub 0}) mode in both a stubbed and an air-drilled phononic-crystal (PC) plate. By measuring simply the radiative acoustic waves of A{sub 0} mode close to the plate surface, we observed the band gaps for the stubbed PC plate caused by either the local resonance or the Bragg scattering, in frequency ranges in good agreement with theoretical predictions. We measured then the complete band gap of A{sub 0} mode for the air-drilled PC plate, in good agreement with the bandmore » structures. Finally, we compared the measurements made using the air-coupled method with those obtained by the laser ultrasonic technique.« less

Spectral plasmonic effect in the nano-cavity of dye-doped nanosphere-based photonic crystals.

PubMed

Yadav, Ashish; Danesh, Mohammad; Zhong, Liubiao; Cheng, Gary J; Jiang, Lin; Chi, Lifeng

2016-04-22

We demonstrated three-dimensional PMMA-based photonic crystal (3D-PC) nanostructures attached to Au nanoparticles (AuNPs), which undergo self-organization into super lattice planes and enhance the fluorescence properties. This new structure exhibited interesting tunable spectral, peak broadening plasmonic behavior because of strong plasmonic interaction at high laser powers. The presented work provides an important tool to improve the efficiency of dye laser applications.

Enhancement of the electrical characteristics of metal-free phthalocyanine films using cold isostatic pressing

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

Matsushima, Toshinori, E-mail: tmatusim@opera.kyushu-u.ac.jp, E-mail: adachi@cstf.kyushu-u.ac.jp; Adachi, Chihaya, E-mail: tmatusim@opera.kyushu-u.ac.jp, E-mail: adachi@cstf.kyushu-u.ac.jp; Japan Science and Technology Agency

2014-12-15

Spatial gaps between grains and other grains, substrates, or electrodes in organic electronic devices are one of the causes of the reduction in the electrical characteristics. In this study, we demonstrate that cold isostatic pressing (CIP) is an effective method to crush the gaps and enhance the electrical characteristics. CIP of metal-free phthalocyanine (H{sub 2}PC) films induced a decrease in the film thickness by 34%–40% because of the gap crush. The connection of smaller grains into a larger grain and planarization of the film surface were also observed in the CIP film. The crystal axes of the H{sub 2}PC crystallitesmore » were rearranged from the a-axis to the c-axis of the α-phase crystal structure in a direction perpendicular to the substrate by CIP, indicating favorable hole injection and transport in this direction because of a better overlap of π orbitals. Thermally stimulated current measurements showed that deep hole traps disappeared and the total hole-trap density decreased after CIP. These CIP-induced changes of the film thicknesses, crystal axes and the hole traps lead to a marked increase in the hole mobility of the H{sub 2}PC films from 2.0 × 10{sup −7} to 4.0 × 10{sup −4} cm{sup 2}/V s by 2000 times in the perpendicular direction. We believe that these findings are important for unveiling the underlying carrier injection and transport mechanisms of organic films and for enhancing the performance of future organic electronic devices.« less

KSC-97PC1382

NASA Image and Video Library

1997-09-08

United States Microgravity Payload-4 (USMP-4) experiments are prepared to be flown on Space Shuttle mission STS-87 in the Space Station Processing Facility at Kennedy Space Center (KSC). This horizontal tube is known as MEPHISTO, the French acronym for a cooperative American-French investigation of the fundamentals of crystal growth. This experiment, designed for the study of solidification (or freezing) during the growth cycle of liquid materials used for semiconductor crystals, aims to aid in the development of techniques for growing higher quality crystals on Earth. All STS-87 experiments are scheduled for launch on Nov. 19 from KSC

Optical Study of 2D Photonic Crystals in an InP/GaInAsP Slab Waveguide Structure

DTIC Science & Technology

2002-01-01

the values n,,,,. = 3.35 and n, ,, = 3.17 are assumed for the refraction index of GaInAsP and InP, respectively. The resulting structure is a multimode...contributes to increase out-of- plane scattering. On the other hand, when entering the PC, the hole pattern is felt as a low refractive index contrast...in an InP/GaInAsP step- index waveguide. Transmission (T) measurements through simple PC slabs and through one-dimensional (1D) Fabry-P6rot (FP

Theoretical modeling of the electronic structure and exchange interactions in Cu(II)Pc

NASA Astrophysics Data System (ADS)

Wu, Wei; Fisher, A. J.; Harrison, N. M.; Wang, Hai; Wu, Zhenlin; Gardener, Jules; Heutz, Sandrine; Jones, Tim; Aeppli, Gabriel

2012-12-01

We calculate the electronic structure and exchange interactions in a copper(II)phthalocyanine (Cu(II)Pc) crystal as a one-dimensional molecular chain using hybrid exchange density functional theory (DFT). In addition, the intermolecular exchange interactions are also calculated in a molecular dimer using Green's function perturbation theory (GFPT) to illustrate the underlying physics. We find that the exchange interactions depend strongly on the stacking angle, but weakly on the sliding angle (defined in the text). The hybrid DFT calculations also provide an insight into the electronic structure of the Cu(II)Pc molecular chain and demonstrate that on-site electron correlations have a significant effect on the nature of the ground state, the band gap and magnetic excitations. The exchange interactions predicted by our DFT calculations and GFPT calculations agree qualitatively with the recent experimental results on newly found η-Cu(II)Pc and the previous results for the α- and β-phases. This work provides a reliable theoretical basis for the further application of Cu(II)Pc to molecular spintronics and organic-based quantum information processing.

Theoretical modeling of the electronic structure and exchange interactions in a Cu(II)Pc one-dimensional chain

NASA Astrophysics Data System (ADS)

Wu, Wei; Fisher, A. J.; Harrison, N. M.

2011-07-01

We calculate the electronic structure and exchange interactions in a copper(II)phthalocyanine [Cu(II)Pc] crystal as a one-dimensional molecular chain using hybrid exchange density functional theory (DFT). In addition, the intermolecular exchange interactions are also calculated in a molecular dimer using Green’s function perturbation theory (GFPT) to illustrate the underlying physics. We find that the exchange interactions depend strongly on the stacking angle, but weakly on the sliding angle (defined in the text). The hybrid DFT calculations also provide an insight into the electronic structure of the Cu(II)Pc molecular chain and demonstrate that on-site electron correlations have a significant effect on the nature of the ground state, the band gap, and magnetic excitations. The exchange interactions predicted by our DFT calculations and GFPT calculations agree qualitatively with the recent experimental results on newly found η-Cu(II)Pc and the previous results for the α and β phases. This work provides a reliable theoretical basis for the further application of Cu(II)Pc to molecular spintronics and organic-based quantum information processing.

?-BiPd: a clean noncentrosymmetric superconductor

NASA Astrophysics Data System (ADS)

Ramakrishnan, Srinivasan; Joshi, Bhanu; Thamizhavel, A.

2017-12-01

We present a comprehensive review of the normal and superconducting state properties of a high-quality single crystal of monoclinic BiPd (?-BiPd, space group ?). The superconductivity of this crystal below 3.8 K is established by measuring its properties using bulk as well as spectroscopic techniques. BiPd is one of the cleanest noncentrosymmetric superconductors that display superconductivity with multiple energy gaps. Evidence of multiple energy gaps was found in heat capacity, point contact (PC) spectroscopy, penetration depth, muon spin rotation, small angle neutron scattering and NMR/NQR measurements. Moreover, Muon spin rotation measurements also suggest strong field dependence of the penetration depth of this superconductor. Unusual superconducting properties due to possible s and p wave mixing are shown by the observation of Andreev bound state in PC measurements as well as the suppressed coherence peak in the temperature dependence of the spin-lattice relaxation in the NQR measurements. This surmise is at variance with the recent STM measurements (different crystal). The observed unusual properties and multiband superconductivity are extremely sensitive to disorder in BiPd. Finally, there is a possibility of tuning the electron correlations by selective substitution in BiPd, thus making it an important system for further investigations.

Complete band gaps of phononic crystal plates with square rods.

PubMed

El-Naggar, Sahar A; Mostafa, Samia I; Rafat, Nadia H

2012-04-01

Much of previous work has been devoted in studying complete band gaps for bulk phononic crystal (PC). In this paper, we theoretically investigate the existence and widths of these gaps for PC plates. We focus our attention on steel rods of square cross sectional area embedded in epoxy matrix. The equations for calculating the dispersion relation for square rods in a square or a triangular lattice have been derived. Our analysis is based on super cell plane wave expansion (SC-PWE) method. The influence of inclusions filling factor and plate thickness on the existence and width of the phononic band gaps has been discussed. Our calculations show that there is a certain filling factor (f=0.55) below which arrangement of square rods in a triangular lattice is superior to the arrangement in a square lattice. A comparison between square and circular cross sectional rods reveals that the former has superior normalized gap width than the latter in case of a square lattice. This situation is switched in case of a triangular lattice. Moreover, a maximum normalized gap width of 0.7 can be achieved for PC plate of square rods embedded in a square lattice and having height 90% of the lattice constant. Copyright © 2011 Elsevier B.V. All rights reserved.

Frequency dependent steering with backward leaky waves via photonic crystal interface layer.

PubMed

Colak, Evrim; Caglayan, Humeyra; Cakmak, Atilla O; Villa, Alessandro D; Capolino, Filippo; Ozbay, Ekmel

2009-06-08

A Photonic Crystal (PC) with a surface defect layer (made of dimers) is studied in the microwave regime. The dispersion diagram is obtained with the Plane Wave Expansion Method. The dispersion diagram reveals that the dimer-layer supports a surface mode with negative slope. Two facts are noted: First, a guided (bounded) wave is present, propagating along the surface of the dimer-layer. Second, above the light line, the fast traveling mode couple to the propagating spectra and as a result a directive (narrow beam) radiation with backward characteristics is observed and measured. In this leaky mode regime, symmetrical radiation patterns with respect to the normal to the PC surface are attained. Beam steering is observed and measured in a 70 degrees angular range when frequency ranges in the 11.88-13.69 GHz interval. Thus, a PC based surface wave structure that acts as a frequency dependent leaky wave antenna is presented. Angular radiation pattern measurements are in agreement with those obtained via numerical simulations that employ the Finite Difference Time Domain Method (FDTD). Finally, the backward radiation characteristics that in turn suggest the existence of a backward leaky mode in the dimer-layer are experimentally verified using a halved dimer-layer structure.

Slow light effect with high group index and wideband by saddle-like mode in PC-CROW

NASA Astrophysics Data System (ADS)

Wan, Yong; Jiang, Li-Jun; Xu, Sheng; Li, Meng-Xue; Liu, Meng-Nan; Jiang, Cheng-Yi; Yuan, Feng

2018-04-01

Slow light with high group index and wideband is achieved in photonic crystal coupled-resonator optical waveguides (PC-CROWs). According to the eye-shaped scatterers and various microcavities, saddle-like curves between the normalized frequency f and wave number k can be obtained by adjusting the parameters of the scatterers, parameters of the coupling microcavities, and positions of the scatterers. Slow light with decent flat band and group index can then be achieved by optimizing the parameters. Simulations prove that the maximal value of the group index is > 104, and the normalized delay bandwidth product within a new varying range of n g > 102 or n g > 103 can be a new and effective criterion of evaluation for the slow light in PC-CROWs.

Phase modification of copper phthalocyanine semiconductor by converting powder to thin film

NASA Astrophysics Data System (ADS)

Ai, Xiaowei; Lin, Jiaxin; Chang, Yufang; Zhou, Lianqun; Zhang, Xianmin; Qin, Gaowu

2018-01-01

Thin films of copper phthalocyanine (CuPc) semiconductor were deposited on glass substrates by a thermal evaporation system using the CuPc powder in a high vacuum. The crystal structures of both the films and the powder were measured by the X-ray diffraction spectroscopy technique. It is observed that CuPc films only show one peak at 6.84°, indicating a high texture of α phase along (200) orientation. In comparison, CuPc powder shows a series of peaks, which are confirmed from the mixture of both α and β phases. The effects of substrate anneal temperature on the film structure, grain size and optical absorption property of CuPc films were also investigated. All the films are of α phase and the full width of half maximum for (200) diffraction peak becomes narrow with increasing the substrate temperatures. The average grain size calculated by the Scherrer's formula is 33.63 nm for the film without anneal, which is increased up to 58.29 nm for the film annealed at 200 °C. Scanning electron microscope was further measured to prove the growth of crystalline grain and to characterize the morphologies of CuPc films. Ultraviolet-visible absorption spectra were employed to study the structure effect on the optical properties of both CuPc films and powder. Fourier Transform infrared spectroscopy was used to identify the crystalline nature of both CuPc powder and film.

Applications of Silicon-on-Insulator Photonic Crystal Structures in Miniature Spectrometer Designs

NASA Astrophysics Data System (ADS)

Gao, Boshen

Optical spectroscopy is one of the most important fundamental scientific techniques. It has been widely adopted in physics, chemistry, biology, medicine and many other research fields. However, the size and weight of a spectrometer as well as the difficulty to align and maintain it have long limited spectroscopy to be a laboratory-only procedure. With the recent advancement in semiconductor electronics and photonics, miniaturized spectrometers have been introduced to complete many tasks in daily life where mobility and portability are necessary. This thesis focuses on the study of several photonic crystal (PC) nano-structures potentially suitable for miniaturized on-chip spectrometer designs. Chapter 1 briefly introduces the concept of PCs and their band structures. By analyzing the band structure, the origin of the superprism effect is explained. Defect-based PC nano-cavities are also discussed, as well as a type of coupled cavity waveguides (CCW) composed of PC nano-cavities. Chapter 2 is devoted to the optimization of a flat-band superprism structure for spectroscopy application using numerical simulations. Chapter 3 reports a fabricated broad-band superprism and the experimental characterization of its wavelength resolving performance. In chapter 4, the idea of composing a miniature spectrometer based on a single tunable PC nano-cavity is proposed. The rest of this chapter discusses the experimental study of this design. Chapter 5 examines the slow-light performance of a CCW and discusses its potential application in slow-light interferometry. Chapter 6 serves as a conclusion of this thesis and proposes directions for possible future work to follow up.

Topological Valley Transport in Two-dimensional Honeycomb Photonic Crystals.

PubMed

Yang, Yuting; Jiang, Hua; Hang, Zhi Hong

2018-01-25

Two-dimensional photonic crystals, in analogy to AB/BA stacking bilayer graphene in electronic system, are studied. Inequivalent valleys in the momentum space for photons can be manipulated by simply engineering diameters of cylinders in a honeycomb lattice. The inequivalent valleys in photonic crystal are selectively excited by a designed optical chiral source and bulk valley polarizations are visualized. Unidirectional valley interface states are proved to exist on a domain wall connecting two photonic crystals with different valley Chern numbers. With the similar optical vortex index, interface states can couple with bulk valley polarizations and thus valley filter and valley coupler can be designed. Our simple dielectric PC scheme can help to exploit the valley degree of freedom for future optical devices.

Hot Spots from Generated Defects in HMX Crystals

NASA Astrophysics Data System (ADS)

Sorensen, Christian; Cummock, Nicholas; O'Grady, Caitlin; Gunduz, I. Emre; Son, Steven

2017-06-01

There are several hot spot initiation mechanisms that have been proposed. However, direct observation of shock or impact compression of these mechanisms at macroscopic scale in explosives is difficult. Phase contrast imaging (PCI) may be applied to these systems. Here, high-speed video was used to record optical spectrum and for x-ray Phase Contrast Imaging (PCI) of shockwave interaction with low defect HMX crystals and crystals with engineered defects. Additionally, multiple crystals were arranged and observed under shock loading with PCI and optical high-speed video. Sample preparation techniques for generating voids and other engineered defects will be discussed. These methods include drilled holes and laser machined samples. Insight into hot spot mechanisms was obtained. Funding from ONR's PC@Xtreme MURI.

Structure and biological function of ENPP6, a choline-specific glycerophosphodiester-phosphodiesterase

PubMed Central

Morita, Junko; Kano, Kuniyuki; Kato, Kazuki; Takita, Hiroyuki; Sakagami, Hideki; Yamamoto, Yasuo; Mihara, Emiko; Ueda, Hirofumi; Sato, Takanao; Tokuyama, Hidetoshi; Arai, Hiroyuki; Asou, Hiroaki; Takagi, Junichi; Ishitani, Ryuichiro; Nishimasu, Hiroshi; Nureki, Osamu; Aoki, Junken

2016-01-01

Choline is an essential nutrient for all living cells and is produced extracellularly by sequential degradation of phosphatidylcholine (PC). However, little is known about how choline is produced extracellularly. Here, we report that ENPP6, a choline-specific phosphodiesterase, hydrolyzes glycerophosphocholine (GPC), a degradation product of PC, as a physiological substrate and participates in choline metabolism. ENPP6 is highly expressed in liver sinusoidal endothelial cells and developing oligodendrocytes, which actively incorporate choline and synthesize PC. ENPP6-deficient mice exhibited fatty liver and hypomyelination, well known choline-deficient phenotypes. The choline moiety of GPC was incorporated into PC in an ENPP6-dependent manner both in vivo and in vitro. The crystal structure of ENPP6 in complex with phosphocholine revealed that the choline moiety of the phosphocholine is recognized by a choline-binding pocket formed by conserved aromatic and acidic residues. The present study provides the molecular basis for ENPP6-mediated choline metabolism at atomic, cellular and tissue levels. PMID:26888014

Atomic imaging of the irreversible sensing mechanism of NO2 adsorption on copper phthalocyanine.

PubMed

Park, Jun Hong; Royer, James E; Chagarov, Evgeniy; Kaufman-Osborn, Tobin; Edmonds, Mary; Kent, Tyler; Lee, Sangyeob; Trogler, William C; Kummel, Andrew C

2013-10-02

Ambient NO2 adsorption onto copper(II) phthalocyanine (CuPc) monolayers is observed using ultrahigh vacuum (UHV) scanning tunneling microscopy (STM) to elucidate the molecular sensing mechanism in CuPc chemical vapor sensors. For low doses (1 ppm for 5 min) of NO2 at ambient temperatures, isolated chemisorption sites on the CuPc metal centers are observed in STM images. These chemisorbates almost completely desorb from the CuPc monolayer after annealing at 100 °C for 30 min. Conversely, for high NO2 doses (10 ppm for 5 min), the NO2 induces a fracture of the CuPc domains. This domain fracture can only be reversed by annealing above 150 °C, which is consistent with dissociative chemisorption into NO and atomic O accompanied by surface restructuring. This high stability implies that the domain fracture results from tightly bound adsorbates, such as atomic O. Existence of atomic O on or under the CuPc layer, which results in domain fracture, is revealed by XPS analysis and ozone-dosing experiments. The observed CuPc domain fracturing is consistent with a mechanism for the dosimetric sensing of NO2 and other reactive gases by CuPc organic thin film transistors (OTFTs).

Bacteriophage T5 encodes a homolog of the eukaryotic transcription coactivator PC4 implicated in recombination-dependent DNA replication.

PubMed

Steigemann, Birthe; Schulz, Annina; Werten, Sebastiaan

2013-11-15

The RNA polymerase II cofactor PC4 globally regulates transcription of protein-encoding genes through interactions with unwinding DNA, the basal transcription machinery and transcription activators. Here, we report the surprising identification of PC4 homologs in all sequenced representatives of the T5 family of bacteriophages, as well as in an archaeon and seven phyla of eubacteria. We have solved the crystal structure of the full-length T5 protein at 1.9Å, revealing a striking resemblance to the characteristic single-stranded DNA (ssDNA)-binding core domain of PC4. Intriguing novel structural features include a potential regulatory region at the N-terminus and a C-terminal extension of the homodimerisation interface. The genome organisation of T5-related bacteriophages points at involvement of the PC4 homolog in recombination-dependent DNA replication, strongly suggesting that the protein corresponds to the hitherto elusive replicative ssDNA-binding protein of the T5 family. Our findings imply that PC4-like factors intervene in multiple unwinding-related processes by acting as versatile modifiers of nucleic acid conformation and raise the possibility that the eukaryotic transcription coactivator derives from ancestral DNA replication, recombination and repair factors. © 2013.

Evaluating a Dutch cardiology primary care plus intervention on the Triple Aim outcomes: study design of a practice-based quantitative and qualitative research.

PubMed

Quanjel, Tessa C C; Spreeuwenberg, Marieke D; Struijs, Jeroen N; Baan, Caroline A; Ruwaard, Dirk

2017-09-06

In an attempt to deal with the pressures on the health-care system and to guarantee sustainability, changes are needed. This study focuses on a cardiology primary care plus intervention. Primary care plus (PC+) is a new health-care delivery model focused on substitution of specialist care in the hospital setting with specialist care in the primary care setting. The intervention consists of a cardiology PC+ centre in which cardiologists, supported by other health-care professionals, provide consultations in a primary care setting. The PC+ centre aims to improve the health of the population and quality of care as experienced by patients, and reduce the number of referrals to hospital-based outpatient specialist care in order to reduce health-care costs. These aims reflect the Triple Aim principle. Hence, the objectives of the study are to evaluate the cardiology PC+ centre in terms of the Triple Aim outcomes and to evaluate the process of the introduction of PC+. The study is a practice-based, quantitative study with a longitudinal observational design, and an additional qualitative study to supplement, interpret and improve the quantitative study. The study population of the quantitative part will consist of adult patients (≥18 years) with non-acute and low-complexity cardiology-related health complaints, who will be referred to the cardiology PC+ centre (intervention group) or hospital-based outpatient cardiology care (control group). All eligible patients will be asked to complete questionnaires at three different time points consisting of questions about their demographics, health status and experience of care. Additionally, quantitative data will be collected about health-care utilization and related health-care costs at the PC+ centre and the hospital. The qualitative part, consisting of semi-structured interviews, focus groups, and observations, is designed to evaluate the process as well as to amplify, clarify and explain quantitative results. This study will evaluate a cardiology PC+ centre using quantitative and supplementary qualitative methods. The findings of both sub-studies will fill a gap in knowledge about the effects of PC+ and in particular whether PC+ is able to pursue the Triple Aim outcomes. NTR6629 (Data registered: 25-08-2017) (registered retrospectively).

Synthesis and X-ray crystal structures of (Mo(CO)(Et{sub 2}PC{sub 2}H{sub 4}PEt{sub 2}){sub 2}){sub 2}({mu}-N{sub 2}) with an end-on bridging dinitrogen ligand and Mo(CO)(Bu{sup i}{sub 2}PC{sub 2}H{sub 4}PBu{sup i}{sub 2}){sub 2} containing an agostic Mo...H-C interaction

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

Luo, X.L.; Kubas, G.J.; Burns, C.J.

1995-12-20

The compound formed by the reaction of trans-Mo(N{sub 2})(Et{sub 2}PC{sub 2}H{sub 4}PEt{sub 2}){sub 2} with ethyl acetate in refluxing toluene under argon has been formulated as the bridging dinitrogen complex (Mo(CO)(Et{sub 2}PC{sub 2}H{sub 4}PEt{sub 2}){sub 2}){sub 2}({mu}-N{sub 2}) (1), in contrast with the previously proposed formulation of Mo(CO)(Et{sub 2}PC{sub 2}H{sub 4}PEt{sub 2}){sub 2} (2). In refluxing p-xylene and under argon, compound 1 eliminates the bridging dinitrogen ligand to form the nitrogen-free compound 2. The reaction of trans-Mo(N{sub 2})(Bu{sup i}{sub 2}PC{sub 2}H{sub 4}PBu{sup i}{sub 2}){sub 2} (3). The molecular structures of compounds 1 and 3 have been determined by single-crystal X-raymore » diffraction studies. Compound 1 contains an end-on bridging dinitrogen ligand. Compound 3 attains a formal 18-electron configuration by virtue of an agostic Mo...H-C interaction between the molybdenum atom and an alphiatic {gamma}-C-H bond of the alkyldiphosphine ligand. On the basis of the agostic Mo...C and Mo...H distances, the agostic interaction in 3 appears to be stronger than that in the related compound Mo(CO)(Ph{sub 2}PC{sub 2}H{sub 4}PPh{sub 2}){sub 2} which involves an ortho aromatic C-H bond of the diphosphine ligand. Crystallographic data for 1: monoclinic, space group C2/c, a=24.270(2){angstrom}, b=44.233(4){angstrom}, c=20.378(2){angstrom}, {beta}=90.725(9){angstrom}, V=21875(3){angstrom}{sup 3}, Z=16, and R=0.048. Crystallographic data for 3: orthorhombic, space group Pna2{sub 1}, a=18.332(4){angstrom}, b=22.0664(4){angstrom}, c=10.589(2){angstrom}, V=4283(2){angstrom}{sup 3}, Z=4, and R=0.034.« less

Radical-lanthanide ferromagnetic interaction in a T bIII bis-phthalocyaninato complex

NASA Astrophysics Data System (ADS)

Komijani, Dorsa; Ghirri, Alberto; Bonizzoni, Claudio; Klyatskaya, Svetlana; Moreno-Pineda, Eufemio; Ruben, Mario; Soncini, Alessandro; Affronte, Marco; Hill, Stephen

2018-02-01

Recent studies have highlighted the importance of organic ligands in the field of molecular spintronics, via which delocalized electron-spin density can mediate magnetic coupling to otherwise localized 4 f moments of lanthanide ions, which show tremendous potential for single-molecule device applications. To this end, high-field/high-frequency electron paramagnetic resonance (EPR) spectroscopy is employed to study a neutral terbium bis-phthalocyaninato metalorganic complex, [TbPc2 ] 0, with the aim of understanding the magnetic interaction between the Ising-like moment of the lanthanide ion and the unpaired spin density on the coordinating organic radical ligand. The measurements were performed on a previously unknown [TbPc2 ] 0 structural phase crystallizing in the Pnma space group. EPR measurements on powder samples of [TbPc2 ] 0 reveal an anisotropic spectrum, which is attributed to the spin-1/2 radical coupled weakly to the EPR-silent T bIII ion. Extensive double-axis rotation studies on a single crystal reveal two independent spin-1/2 signals with differently oriented (albeit identical) uniaxial g -tensors, in complete agreement with x-ray structural studies that indicate two molecular orientations within the unit cell. The easy-axis nature of the radical EPR spectra thus reflects the coupling to the Ising-like T bIII moment. This is corroborated by studies of the isostructural [YPc2 ] 0 analog (where Y is nonmagnetic yttrium), which gives a completely isotropic radical EPR signal. The experimental results for the terbium complex are well explained on the basis of an effective model that introduces a weak ferromagnetic Heisenberg coupling between an isotropic spin-1/2 and an anisotropic spin-orbital moment, J =6 , that mimics the known, strong easy-axis Tb ⋯P c2 crystal-field interaction.

Crystal structure of an antibody bound to an immunodominant peptide epitope: novel features in peptide-antibody recognition.

PubMed

Nair, D T; Singh, K; Sahu, N; Rao, K V; Salunke, D M

2000-12-15

The crystal structure of Fab of an Ab PC283 complexed with its corresponding peptide Ag, PS1 (HQLDPAFGANSTNPD), derived from the hepatitis B virus surface Ag was determined. The PS1 stretch Gln2P to Phe7P is present in the Ag binding site of the Ab, while the next three residues of the peptide are raised above the binding groove. The residues Ser11P, Thr12P, and Asn13P then loop back onto the Ag-binding site of the Ab. The last two residues, Pro14P and Asp15P, extend outside the binding site without forming any contacts with the Ab. The PC283-PS1 complex is among the few examples where the light chain complementarity-determining regions show more interactions than the heavy chain complementarity-determining regions, and a distal framework residue is involved in Ag binding. As seen from the crystal structure, most of the contacts between peptide and Ab are through the five residues, Leu3-Asp4-Pro5-Ala6-Phe7, of PS1. The paratope is predominantly hydrophobic with aromatic residues lining the binding pocket, although a salt bridge also contributes to stabilizing the Ag-Ab interaction. The molecular surface area buried upon PS1 binding is 756 A(2) for the peptide and 625 A(2) for the Fab, which is higher than what has been seen to date for Ab-peptide complexes. A comparison between PC283 structure and a homology model of its germline ancestor suggests that paratope optimization for PS1 occurs by improving both charge and shape complementarity.

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

Zhao, Shuling; Zhang, Gaozhan; Dai, Xuejuan

Rice stripe virus (RSV) belongs to the genus Tenuivirus and its genome consists of four single-stranded RNAs encoding seven proteins. Here, we have analyzed the processing and membrane association of Pc2 encoded by vcRNA2 in insect cells. The enhanced green fluorescent protein (eGFP) was fused to the Pc2 and used for the detection of Pc2 fusion proteins. The results showed that Pc2 was cleaved to produce two proteins named Pc2-N and Pc2-C. When expressed alone, either Pc2-N or Pc2-C could transport to the Endoplasmic reticulum (ER) membranes independently. Further mutagenesis studies revealed that Pc2 contained three ER-targeting domains. The resultsmore » led us to propose a model for the topology of the Pc2 in which an internal signal peptide immediately followed a cleavage site, and two transmembrane regions are contained.« less

Transforming PC Power Supplies into Smart Car Battery Conditioners

ERIC Educational Resources Information Center

Rodriguez-Ascariz, J. M.; Boquete-Vazquez, L.

2011-01-01

This paper describes a laboratory project consisting of a PC power supply modification into an intelligent car-battery conditioner with both wireless and wired networking capabilities. Adding a microcontroller to an average PC power supply transforms it into a flexible, intelligent device that can be configured and that is suitable to keep car…

Integration of both dense wavelength-division multiplexing and coarse wavelength-division multiplexing demultiplexer on one photonic crystal chip

NASA Astrophysics Data System (ADS)

Tian, Huiping; Shen, Guansheng; Liu, Weijia; Ji, Yuefeng

2013-07-01

An integrated model of photonic crystal (PC) demultiplexer that can be used to combine dense wavelength-division multiplexing (DWDM) and coarse wavelength-division multiplexing (CWDM) systems is first proposed. By applying the PC demultiplexer, dense channel spacing 0.8 nm and coarse channel spacing 20 nm are obtained at the same time. The transmission can be improved to nearly 90%, and the crosstalk can be decreased to less than -18 dB by enlarging the width of the bus waveguide. The total size of the device is 21×42 μm2. Four channels on one side of the demultiplexer can achieve DWDM in the wavelength range between 1575 and 1578 nm, and the other four channels on the other side can achieve CWDM in the wavelength range between 1490 and 1565 nm, respectively. The demonstrated demultiplexer can be applied in the future CWDM and DWDM system, and the architecture costs can be significantly reduced.

Analytical study of mode degeneracy in non-Hermitian photonic crystals with TM-like polarization

NASA Astrophysics Data System (ADS)

Yin, Xuefan; Liang, Yong; Ni, Liangfu; Wang, Zhixin; Peng, Chao; Li, Zhengbin

2017-08-01

We present a study of the mode degeneracy in non-Hermitian photonic crystals (PC) with TM-like polarization and C4 v symmetry from the perspective of the coupled-wave theory (CWT). The CWT framework is extended to include TE-TM coupling terms which are critical for modeling the accidental triple degeneracy within non-Hermitian PC systems. We derive the analytical form of the wave function and the condition of Dirac-like-cone dispersion when radiation loss is relatively small. We find that, similar to a real Dirac cone, the Dirac-like cone in non-Hermitian PCs possesses good linearity and isotropy, even with a ring of exceptional points (EPs) inevitably existing in the vicinity of the second-order Γ point. However, the Berry phase remains zero at the Γ point, indicating the cone does not obey the Dirac equation and is only a Dirac-like cone. The topological modal interchange phenomenon and nonzero Berry phase of the EPs are also discussed.

Room-temperature, solution-processable organic electron extraction layer for high-performance planar heterojunction perovskite solar cells

DOE PAGES

Kim, Jong H.; Chueh, Chu-Chen; Williams, Spencer T.; ...

2015-09-24

Here in this work, we describe a room-temperature, solution-processable organic electron extraction layer (EEL) for high-performance planar heterojunction perovskite solar cells (PHJ PVSCs). This EEL is composed of a bilayered fulleropyrrolidinium iodide (FPI)-polyethyleneimine (PEIE) and PC 61BM, which yields a promising power conversion efficiency (PCE) of 15.7% with insignificant hysteresis. We reveal that PC 61BM can serve as a surface modifier of FPI-PEIE to simultaneously facilitate the crystallization of perovskite and the charge extraction at FPI-PEIE/CH 3NH 3PbI 3 interface. Furthermore, the FPI-PEIE can also tune the work function of ITO and dope PC 61BM to promote the efficient electronmore » transport between ITO and PC 61BM. Based on the advantages of room-temperature processability and decent electrical property of FPI-PEIE/PC 61BM EEL, a high-performance flexible PVSC with a PCE ~10% is eventually demonstrated. Lastly, this study shows the potential of low-temperature processed organic EEL to replace transition metal oxide-based interlayers for highly printing compatible PVSCs with high-performance.« less

Design for a broad non-transmission band gap of three-color filters using photonic heterostructures

NASA Astrophysics Data System (ADS)

Li, Hongfei; Guan, Huihuan; Han, Peide; Li, Yuping; Zhang, Caili

2013-01-01

The bandgap characteristics of one-dimensional (1D) photonic crystal (PC) heterostructures containing defects are studied using the transfer matrix method. The key is to search for the best combination style for different 1D PCs to form heterostructures containing Si/MgF2 multilayer films. The non-transmission range over the entire visible range can be enlarged substantially, and the phenomenon of three-color PC filters in blue-green-red light can be realized by adjusting the repeat cycle counts of various PCs. With perfect omnidirectional and high peak transmission three-color filters for the electric magnetic (TE) mode, this optimization design opens a promising way to fabricate three-color PC filters with a wide non-transmission range in the visible range, which can be applied to white LEDs.

Hybridization bandgap induced by an electrical resonance in piezoelectric metamaterial plates

NASA Astrophysics Data System (ADS)

Kherraz, N.; Haumesser, L.; Levassort, F.; Benard, P.; Morvan, B.

2018-03-01

We demonstrate numerically and experimentally the opening of a locally resonant bandgap in an active phononic crystal (PC) made of a homogeneous piezoelectric plate covered by a 1D periodic array of thin electrodes connected to inductive shunts. The application of periodic electrical boundary conditions (EBCs) enables an at will tailoring of the dispersion properties of the PC plate, thus leading to a control of the dispersion of the propagating guided elastic waves in the plate. Depending on the nature of the EBCs, several bandgaps open up, the most important being a Hybridization Bandgap (HBG) in the subwavelength regime. The PC behaves as a locally resonant metamaterial. The HBG originates from the interaction of propagating elastic waves (Lamb modes) with an electrical resonant mode whose dispersion can be effectively described through an equivalent transmission line model.

Integration of the Reconfigurable Self-Healing eDNA Architecture in an Embedded System

NASA Technical Reports Server (NTRS)

Boesen, Michael Reibel; Keymeulen, Didier; Madsen, Jan; Lu, Thomas; Chao, Tien-Hsin

2011-01-01

In this work we describe the first real world case study for the self-healing eDNA (electronic DNA) architecture by implementing the control and data processing of a Fourier Transform Spectrometer (FTS) on an eDNA prototype. For this purpose the eDNA prototype has been ported from a Xilinx Virtex 5 FPGA to an embedded system consisting of a PowerPC and a Xilinx Virtex 5 FPGA. The FTS instrument features a novel liquid crystal waveguide, which consequently eliminates all moving parts from the instrument. The addition of the eDNA architecture to do the control and data processing has resulted in a highly fault-tolerant FTS instrument. The case study has shown that the early stage prototype of the autonomous self-healing eDNA architecture is expensive in terms of execution time.

Chemical sensing of copper phthalocyanine sol-gel glass through organic vapors

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

Ridhi, R.; Gawri, Isha; Abbas, Saeed J.

2015-05-15

The sensitivities of metallophthalocyanine to vapor phase electron donors has gained significance in many areas and disciplines due to their sensing properties and ease of operation. In the present study the interaction mechanism of organic vapors in Copper Phthalocyanine (CuPc) sol-gel glass has been studied. The interaction mechanism is affected by many factors like morphology, electrical or optical properties of film. CuPc sol-gel glass has been synthesized using chemical route sol-gel method. Its structural characterization was conducted using XRD and the amorphous nature of the silicate glass was observed with characteristic α polymorph phase of CuPc at around 6.64° withmore » 13.30Å interplanar spacing. The size of the particle as determined using Debbye Scherre’s formula comes out around 15.5 nm. The presence of α phase of CuPc was confirmed using FTIR with the appearance of crystal parameter marker band at 787 cm-1. Apart from this A2u and Eu symmetry bands of CuPc have also been observed. The UV absorption spectrum of CuPc exhibits absorption peaks owing to π→ π* and n→ π* transitions. A blue shift in the prepared CuPc glass has been observed as compared to the dopant CuPc salt indicating increase of band gap. A split in B (Soret) band and Q band appears as observed with the help of Lorentzian fitting. CuPc sol gel glass has been exposed with chemical vapors of Methanol, Benzene and Bromine individually and the electrical measurements have been carried out. These measurements show the variation in conductivity and the interaction mechanism has been analyzed.« less

FGF2 Stimulation of the Pyrophosphate-Generating Enzyme, PC-1, in Pre-Osteoblast Cells Is Mediated by RUNX2

PubMed Central

Hatch, Nan E; Li, Yan; Franceschi, Renny T

2009-01-01

Pyrophosphate is an established inhibitor of hydroxyapatite deposition and crystal growth, yet when hydrolyzed into phosphate, it becomes a substrate for hydroxyapatite deposition. Pyrophosphate-generating enzyme (PC-1), Ank, and tissue nonspecific alkaline phosphatase (Tnap) are three factors that regulate extracellular pyrophosphate levels through its generation, transport, and hydrolysis. We previously showed that fibroblast growth factor 2 (FGF2) induces PC-1 and Ank while inhibiting Tnap expression and mineralization in MC3T3E1(C4) calvarial pre-osteoblast cells. In this study, we showed similar FGF2 regulation of these genes in primary pre-osteoblast cultures. In contrast to Ank and Tnap that are regulated by FGF2 in multiple cell types, we found regulation of PC-1 to be selective to pre-osteoblastic cells and to require the osteoblast-related transcription factor, Runx2. Specifically, FGF2 was unable to induce PC-1 expression in Runx2-negative nonbone cells or in calvarial cells from Runx2-deficient mice. Transfection of these cells with a Runx2 expression vector restored FGF2 responsiveness. FGF2 was also shown to stimulate recruitment of Runx2 to the endogenous PC-1 promoter in MC3T3E1(C4) cells, as measured by chromatin immunoprecipitation. Taken together, our results establish that FGF2 is a specific inducer of PC-1 in pre-osteoblast cells and that FGF2 induces PC-1 expression through a mechanism involving Runx2. PMID:19049325

Switchable multiwavelength erbium-doped photonic crystal fiber ring laser based on a length of polarization-maintaining photonic crystal fiber

NASA Astrophysics Data System (ADS)

Cheng, Jianqun; Ruan, Shuangchen

2011-11-01

A switchable multi-wavelength Erbium-doped photonic crystal fiber (ED-PCF) ring laser based on a length of polarization-maintaining photonic crystal fiber(PM-PCF) is presented and demonstrated experimentally. A segment of ED-PCF is used as linear gain medium in the resonant cavity. Due to the polarization hole burning (PHB) caused by the PM-PCF and a polarization controller (PC), the laser can operate in stable dual- or triple- wavelength modes at room temperature. The optical signal-to-noise ratio (OSNR) of the laser without any wavelength-selective components is greater than 30 dB. The amplitude variations of lasing peaks in ten minutes are less than 0.26dB for two different operating modes.

Switchable multiwavelength erbium-doped photonic crystal fiber ring laser based on a length of polarization-maintaining photonic crystal fiber

NASA Astrophysics Data System (ADS)

Cheng, Jianqun; Ruan, Shuangchen

2012-03-01

A switchable multi-wavelength Erbium-doped photonic crystal fiber (ED-PCF) ring laser based on a length of polarization-maintaining photonic crystal fiber(PM-PCF) is presented and demonstrated experimentally. A segment of ED-PCF is used as linear gain medium in the resonant cavity. Due to the polarization hole burning (PHB) caused by the PM-PCF and a polarization controller (PC), the laser can operate in stable dual- or triple- wavelength modes at room temperature. The optical signal-to-noise ratio (OSNR) of the laser without any wavelength-selective components is greater than 30 dB. The amplitude variations of lasing peaks in ten minutes are less than 0.26dB for two different operating modes.

Investigation of the Photocurrent in Hot-Wall-Epitaxy-Grown BaIn2S4 Layers

NASA Astrophysics Data System (ADS)

You, S. H.; Hong, K. J.; Jeong, T. S.; Youn, C. J.

2015-12-01

The photocurrent (PC) of hot-wall-epitaxy-grown BaIn2S4 layers was studied at different temperatures and for different photoresponse intensities. With increasing temperature, the position of the PC spectra tended to shift toward longer wavelength. These PC peaks corresponded to band-to-band transitions caused by intrinsic transitions from the valence band states to the conduction band states. Also, the bandgap variations were well matched by the equation E g( T) = E g(0) - 3.79 × 10-3 T 2/( T + 499), where E g(0) was estimated to be 3.0597 eV, 3.2301 eV, and 3.2606 eV for transitions corresponding to the valence band states Γ 4(z), Γ 5(x), and Γ 5(y), respectively. By use of the selection rule and results from the PC spectroscopy, the crystal field and the spin-orbit splitting were found to be 0.1703 and 0.0306 eV, respectively. Thus, the PC intensity gradually decreased with decreasing temperature. The decrease of PC intensity was caused by the presence of trapping centers associated with native defects in the BaIn2S4 layers. The trap level was found to be a shallow donor-level type of 20.4 meV, 1.6 meV below the conduction band. Consequently, these trap levels, which are related to native defects in BaIn2S4 layers, are believed to limit PC intensity with decreasing temperature.

75 FR 37382 - Notice of Antidumping Duty Order: Prestressed Concrete Steel Wire Strand from the People's...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-29

... strand (``PC strand'') from the People's Republic of China (``PRC''). On June 22, 2010, the ITC notified... investigation of PC strand from the PRC. See Prestressed Concrete Steel Wire Strand From the People's Republic... Determination''). Scope of the Order The scope of this investigation consists of PC strand, produced from wire...

Spin tuning of electron-doped metal-phthalocyanine layers.

PubMed

Stepanow, Sebastian; Lodi Rizzini, Alberto; Krull, Cornelius; Kavich, Jerald; Cezar, Julio C; Yakhou-Harris, Flora; Sheverdyaeva, Polina M; Moras, Paolo; Carbone, Carlo; Ceballos, Gustavo; Mugarza, Aitor; Gambardella, Pietro

2014-04-09

The spin state of organic-based magnets at interfaces is to a great extent determined by the organic environment and the nature of the spin-carrying metal center, which is further subject to modifications by the adsorbate-substrate coupling. Direct chemical doping offers an additional route for tailoring the electronic and magnetic characteristics of molecular magnets. Here we present a systematic investigation of the effects of alkali metal doping on the charge state and crystal field of 3d metal ions in Cu, Ni, Fe, and Mn phthalocyanine (Pc) monolayers adsorbed on Ag. Combined X-ray absorption spectroscopy and ligand field multiplet calculations show that Cu(II), Ni(II), and Fe(II) ions reduce to Cu(I), Ni(I), and Fe(I) upon alkali metal adsorption, whereas Mn maintains its formal oxidation state. The strength of the crystal field at the Ni, Fe, and Mn sites is strongly reduced upon doping. The combined effect of these changes is that the magnetic moment of high- and low-spin ions such as Cu and Ni can be entirely turned off or on, respectively, whereas the magnetic configuration of MnPc can be changed from intermediate (3/2) to high (5/2) spin. In the case of FePc a 10-fold increase of the orbital magnetic moment accompanies charge transfer and a transition to a high-spin state.

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

Li, Jingcheng; Wang, Yu; Li, Bin, E-mail: libin@mail.ustc.edu.cn, E-mail: bwang@ustc.edu.cn

We investigate the modification of electronic properties of single cobalt phthalocyanine (CoPc) molecule by an extra Co atom co-adsorbed on Au (111) surface using scanning tunneling microscopy (STM), joint with density functional theory (DFT) calculations. By manipulating CoPc molecules using the STM tip to contact individually adsorbed Co atom, two types of relatively stable complexes can be formed, denoted as CoPc-Co(I) and CoPc-Co(II). In CoPc-Co(I), the Co atom is at an intramolecular site close to aza-N atom of CoPc, which induces significant modifications of the electronic states of CoPc, such as energy shifts and splitting of nonlocal molecular orbitals. However,more » in CoPc-Co(II) where the Co atom is underneath a benzene lobe of CoPc, it only slightly modifies the electronic states of CoPc, and mainly local characteristics of specific molecular orbitals are affected, even though CoPc-Co(II) is more stable than CoPc-Co(I). Our DFT calculations give consistent results with the experiments, and related analyses based on the molecular orbital theory reveal mechanism behind the experimental observations.« less

Intermixing behaviors of PCBM with CuPc on Au(1 1 1) surface

NASA Astrophysics Data System (ADS)

Masui, Akane; Sakaue, Hiroyuki; Takahagi, Takayuki; Suzuki, Hitoshi

2016-09-01

The behavior of phenyl-C61-butyric acid methyl ester (PCBM) and copper-phthalocyanine (CuPc) on a Au(1 1 1) surface was investigated using scanning tunneling microscopy (STM). When CuPc was deposited in addition to PCBM it entered and disturbed the regularly spaced double row superstructure of the PCBM molecules. PCBM intermixed with CuPc to form a new square shaped superstructure that consisted of six to eight PCBM molecules with a CuPc molecule in its center. The intermixing of these materials that was observed indicated that they possessed an attractive interaction.

A new electrode design for ambipolar injection in organic semiconductors.

PubMed

Kanagasekaran, Thangavel; Shimotani, Hidekazu; Shimizu, Ryota; Hitosugi, Taro; Tanigaki, Katsumi

2017-10-17

Organic semiconductors have attracted much attention for low-cost, flexible and human-friendly optoelectronics. However, achieving high electron-injection efficiency is difficult from air-stable electrodes and cannot be equivalent to that of holes. Here, we present a novel concept of electrode composed of a bilayer of tetratetracontane (TTC) and polycrystalline organic semiconductors (pc-OSC) covered by a metal layer. Field-effect transistors of single-crystal organic semiconductors with the new electrodes of M/pc-OSC/TTC (M: Ca or Au) show both highly efficient electron and hole injection. Contact resistance for electron injection from Au/pc-OSC/TTC and hole injection from Ca/pc-OSC/TTC are comparable to those for electron injection from Ca and hole injection from Au, respectively. Furthermore, the highest field-effect mobilities of holes (22 cm 2  V -1  s -1 ) and electrons (5.0 cm 2  V -1  s -1 ) are observed in rubrene among field-effect transistors with electrodes so far proposed by employing Ca/pc-OSC/TTC and Au/pc-OSC/TTC electrodes for electron and hole injection, respectively.One of technological challenges building organic electronics is efficient injection of electrons at metal-semiconductor interfaces compared to that of holes. The authors show an air-stable electrode design with induced gap states, which support Fermi level pinning and thus ambipolar carrier injection.

VizieR Online Data Catalog: Search for extraterrestrial intelligence (Isaacson+, 2017)

NASA Astrophysics Data System (ADS)

Isaacson, H.; Siemion, A. P. V.; Marcy, G. W.; Lebofsky, M.; Price, D. C.; MacMahon, D.; Croft, S.; Deboer, D.; Hickish, J.; Werthimer, D.; Sheikh, S.; Hellbourg, G.; Enriquez, J. E.

2017-08-01

The stellar sample is defined by two selection criteria. The first is a volume-limited sample of stars within 5pc of the Sun. The second is a spectral class complete sample consisting of stars across the main sequence and some giant branch stars, all within 50pc. We combined the two sub-samples (5pc and 5-50pc) to produce the final set of 1709 target stars that are listed in Table 1. (1 data file).

Basic Research in Electronics (JSEP)

DTIC Science & Technology

1991-12-01

Single Crystal Growth Single crystals of Bi2Sr 2 CaCu2 O8 (BSCCO) have been prepared following the method of Mitzi , et al. [241. A mixture of oxides...P.C. van Son, H. van Kempen and P. Wyder, Phys. Rev. Lett., 50 2226 (1987). [24] D.B. Mitzi , L.W. Lombardo, A. Kapitulnik,/S.S. Laderman and R.D...Phys. Rev., 165 837 (1908). P.C. van Son, H. van Kempen and P. Wyder, Phys. Rev. Lett., 59 2228 (1987). D.B. Mitzi , L.W. Lombardo, A. Kapitulnik

Physical and Instrumental Considerations in the Use of Lithium Phthalocyanine for Measurements of the Concentration of the Oxygen

NASA Astrophysics Data System (ADS)

Smirnov, A. I.; Norby, S. W.; Walczak, T.; Liu, K. J.; Swartz, H. M.

The use of crystals of lithium phthalocyanine (LiPc) to measure the concentration of oxygen in vivo and in vitro by electron paramagnetic resonance leads to experimental constraints due to the very narrow EPR lines that may occur (as narrow as 11-13 mG in the absence of O 2), distortions induced by the automatic frequency control system, anisotropy in the spectra (orientation-dependent linewidth is 11-17 mG in the absence of O 2), microwave power saturation, and the effect of physiological motion. These constraints can be overcome if recognized. This article highlights the experimental and theoretical basis of these properties of the EPR signal of LiPc and suggests some technical solutions. It is most important to recognize that paramagnetic species such as LiPc present problems that are not commonly encountered in EPR spectroscopy.

Reducing support loss in micromechanical ring resonators using phononic band-gap structures

NASA Astrophysics Data System (ADS)

Hsu, Feng-Chia; Hsu, Jin-Chen; Huang, Tsun-Che; Wang, Chin-Hung; Chang, Pin

2011-09-01

In micromechanical resonators, energy loss via supports into the substrates may lead to a low quality factor. To eliminate the support loss, in this paper a phononic band-gap structure is employed. We demonstrate a design of phononic-crystal (PC) strips used to support extensional wine-glass mode ring resonators to increase the quality factor. The PC strips are introduced to stop elastic-wave propagation by the band-gap and deaf-band effects. Analyses of resonant characteristics of the ring resonators and the dispersion relations, eigenmodes, and transmission properties of the PC strips are presented. With the proposed resonator architecture, the finite-element simulations show that the leaky power is effectively reduced and the stored energy inside the resonators is enhanced simultaneously as the operating frequencies of the resonators are within the band gap or deaf bands. Realization of a high quality factor micromechanical ring resonator with minimized support loss is expected.

Tunneling electron induced chemisorption of copper phthalocyanine molecules on the Cu(111) surface

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

Stock, T.; Nogami, J.

2014-02-17

The adsorption of up to one monolayer (ML) of copper phthalocyanine (CuPc) molecules on a room temperature Cu(111) surface has been studied using scanning tunneling microscopy (STM). Below 1 ML the molecules are in a fluid state and are highly mobile on the surface. At 1 ML coverage the molecules coalesce into a highly ordered 2D crystal phase. At sub-ML coverages, chemisorption of individual CuPc molecules can be induced through exposure to tunneling electrons at a tunneling bias voltage exceeding a threshold value. This tunneling electron induced effect has been exploited to perform molecular STM lithography.

Study of temperature-dependent Raman spectroscopy and electrical properties in [001]-oriented 0.35Pb(In1/2Nb1/2)O3-0.35Pb(Mg1/3Nb2/3)O3-0.30PbTiO3-Mn single crystals

NASA Astrophysics Data System (ADS)

Liu, Xing; Fang, Bijun; Deng, Ji; Yan, Hong; Deng, Hao; Yue, Qingwen; Ding, Jianning; Zhao, Xiangyong; Luo, Haosu

2016-01-01

In this work, the temperature-dependent Raman spectra and electrical properties of the [001]-oriented 0.5 mol. % Mn-doped 0.35Pb(In1/2Nb1/2)O3-0.35Pb(Mg1/3Nb2/3)O3-0.30PbTiO3-Mn (PIMNT-Mn) single crystals were investigated. All the unpoled and poled PIMNT-Mn single crystals experience a ferroelectric tetragonal phase to paraelectric cubic phase transition (FET-PC) around 183 °C (TC), which exhibits a second-order transition behavior. Whereas, the poled PIMNT-Mn single crystals exhibit another two dielectric anomalies around 130 °C (TRM) and 148 °C (TMT), in which the ferroelectric rhombohedral phase to ferroelectric monoclinic phase (FER-FEM) and the ferroelectric monoclinic phase to ferroelectric tetragonal phase (FEM-FET) transitions take place, respectively. Both the two ferroelectric phase transitions exhibit a first-order transition behavior. The discontinuous change of the phase degree (θ) and frequencies (fr and fa) around TRM suggest the occurrence of the FER-FEM phase transition in the poled PIMNT-Mn single crystals. The narrowing of the 510 cm-1 and 582 cm-1 Raman modes around the TRM, TMT, and TC temperatures shown in the temperature-dependent Raman spectra suggests their increased ordering of the local structure. The intensity ratio of I272 cm-1/I801 cm-1 increases obviously around the phase transition temperatures (TRM, TMT, and TC), indicating the reduction of the long-range order. The anomalous broadening of the 272 cm-1 Raman mode around the TRM, TMT, and TC temperatures indicates the occurrence of the successive ferroelectric phase transitions (FER-FEM, FEM-FET, and FET-PC) with increasing temperature in the poled PIMNT-Mn single crystals.

Improvement in the Viability of Cryopreserved Cells by Microencapsulation

NASA Astrophysics Data System (ADS)

Matsumoto, Yoshifumi; Morinaga, Yukihiro; Ujihira, Masanobu; Oka, Kotaro; Tanishita, Kazuo

The advantages of microencapsulated cells over those of suspended cells were evaluated for improving viability in cryopreservation. Rat pheochromocytoma (PC12) cells were selected as the test biological cells and then microencapsulated in alginate-polylysine-alginate membranes. These microencapsulated PC12 cells were frozen by differential scanning calorimetry (DSC) at various cooling rates, from 0.5 to 10°C/min. Their latent heat was measured during freezing from 4 to -80°C. The post-thaw viability was evaluated by dopamine-concentration measurement and by trypan blue exclusion assay. Results showed that at cooling rates of 0.5 and 1°C/min, the latent heat of microencapsulated PC12 cells was lower than that of suspended cells. This lower latent heat is caused by the fact that the extra-microcapsule froze and the intra-capsule remained unfrozen due to the formation of ice crystals in the extra-capsule space. The post-thaw viability of microencapsulated PC12 cells was improved when the cooling rate was 0.5 or 1°C/min, compared with that of suspended cells. Therefore, in microencapsulated PC12 cells, maintaining the intra-microcapsules in an unfrozen state during freezing reduces the solution effect and thus improves the post-thaw viability.

A remote access ecg monitoring system - biomed 2009.

PubMed

Ogawa, Hidekuni; Yonezawa, Yoshiharu; Maki, Hiromichi; Iwamoto, Junichi; Hahn, Allen W; Caldwell, W Morton

2009-01-01

We have developed a remotely accessible telemedicine system for monitoring a patient's electrocardiogram (ECG). The system consists of an ECG recorder mounted on chest electrodes and a physician's laptop personal computer. This ECG recorder is designed with a variable gain instrumentation amplifier; a low power 8-bit single-chip microcomputer; two 128KB EEPROMs and 2.4 GHz low transmit power mobile telephone. When the physician wants to monitor the patient's ECG, he/she calls directly from the laptop PC to the ECG recorder's phone and the recorder sends the ECG to the computer. The electrode-mounted recorder continuously samples the ECG. Additionally, when the patient feels a heart discomfort, he/she pushes a data transmission switch on the recorder and the recorder sends the recorded ECG waveforms of the two prior minutes, and for two minutes after the switch is pressed. The physician can display and monitor the data on the computer's liquid crystal display.

Rich Variety of Three-Dimensional Nanostructures Enabled by Geometrically Constraining Star-like Block Copolymers.

PubMed

Wang, Chao; Xu, Yuci; Li, Weihua; Lin, Zhiqun

2016-08-09

The influence of star-like architecture on phase behavior of star-like block copolymer under cylindrical confinement differs largely from the bulk (i.e., nonconfinement). A set of intriguing self-assembled morphologies and the corresponding phase diagrams of star-like (AB)f diblock copolymers with different numbers of arms f (i.e., f = 3, 9, 15, and 21) in four scenarios (ϕA = 0.3 and V0 > 0; ϕA = 0.3 and V0 < 0; ϕA = 0.7 and V0 > 0; and ϕA = 0.7 and V0 < 0 (where ϕA is the volume fraction of A block) and V0 < 0 and V0 > 0 represent that the pore wall of cylindrical confinement prefers the inner A block (i.e., A-preferential) and B block (i.e., B-preferential), respectively) were for the first time scrutinized by employing the pseudospectral method of self-consistent mean-field theory. Surprisingly, a new nanoscopic phase, that is, perforated-lamellae-on-cylinder (denoted PC), was observed in star-like (AB)3 diblock copolymer at ϕA = 0.3 and V0 > 0. With a further increase in f, a single lamellae (denoted L1) was found to possess a larger phase region. Under the confinement of A-preferential wall (i.e., V0 < 0) at ϕA = 0.3, PC phase became metastable and its free energy increased as f increased. Quite intriguingly, when ϕA = 0.7 and V0 > 0, where an inverted cylinder was formed in bulk, the PC phase became stable, and its free energy decreased as f increased, suggesting the propensity to form PC phase under this condition. Moreover, in stark contrast to the phase transition of C1 → L1 → PC (C1, a single cylindrical microdmain) at ϕA = 0.3 and V0 > 0, when subjected to the A-preferential wall (ϕA = 0.7), a different phase transition sequence (i.e., C1 → PC → L1) was identified due to the formation of a double-layer structure. On the basis of our calculations, the influence of star-like architecture on (AB)f diblock copolymer under the imposed cylindrical confinement, particularly the shift of the phase boundaries as a function of f, was thoroughly understood. These self-assembled nanostructures may hold the promise for applications as lithographic templates for nanowires, photonic crystals, and nanotechnology.

[Risk analysis and assessment of occupational hazard fromindiumand its compounds in manufacture of liquid crystal display panel].

PubMed

Qiu, Haili; Zhou, Wei; Li, Zhimin; Tian, Dongchao; Weng, Shaofan; He, Juntao

2015-08-01

To understand the exposed positions and levels of indium and its compounds in manufacture of liquid crystal displays, and to evaluate the degree of occupational hazard from indium and its compounds. On-site investigation of occupational health, occupational hazard monitoring, and occupational health examination were used to evaluate the degree of occupational hazard from indium and its compounds in three manufacturers of liquid crystal display panel in Shenzhen, Guangdong, China. The time-weighted average (TWA) and short-term exposure limit (STEL) concentrations of indium and its compounds to which sputtering machine operating positions were exposed were less than 0.002~0.004 mg/m³ and 0.006~0.007 mg/m³, respectively, both of which complied with the National Hygienic Standard (PC-TWA = 0.1 mg/m³; PC-STEL = 0.3 mg/m³); the TWA and STEL concentrations of indium and its compounds to which grinding positions were exposed were 0.114~2.98 mg/m³ and 0.31~10.02 mg/m³, respectively, both of which exceeded the National Hygienic Standard with the highest concentration 33-fold higher than the standard. No significant health damages were found in exposed workers according to the results of occupational health examination. The grinding positions are the key to the control of occupational hazard from indium and its compounds in manufacture of liquid crystal display panel. The workers should be equipped with the anti-particulate full-face respirator, which is an effective way to prevent occupational hazard from indium and its compounds.

Terahertz transmission properties of a triadic-Cantor-set photonic crystal containing a semiconductor

NASA Astrophysics Data System (ADS)

King, Tzu-Chyang; Liu, Chi-Chung; Huang, Chih-Hsi; Wu, Chien-Jang

2016-08-01

Terahertz transmission properties of a stage 3 triadic-Cantor-set photonic crystal (S3 TCS PC) containing a semiconductor of n-InSb are theoretically investigated. With the resonant frequency in the permittivity function of n-InSb, transmission responses can be classified as three regions. In the two regions with frequencies well above and below the resonant frequency, the permittivity functions are nearly a positive constant and n-InSb is dielectric-like. For these two regions, transmittance response of S3 TCS PC at a given number of periods Np reveals that, within a photonic band gap, there are two groups of defect modes with numbers of Np and Np-1, respectively. Defect modes are shown to be blue-shifted as the angle of incidence increases for both TE and TM waves. Additionally, adjusting the layer thickness enables us to control mode positions for the group of (Np-1)-mode, but the one with Np-mode is not able to be controlled. In a region of 5.1-6.2 THz, where the loss is large, there also are many transmission modes.

Reversible thermochromic response based on photonic crystal structure in butterfly wing

NASA Astrophysics Data System (ADS)

Wang, Wanlin; Wang, Guo Ping; Zhang, Wang; Zhang, Di

2018-01-01

Subtle responsive properties can be achieved by the photonic crystal (PC) nanostructures of butterfly based on thermal expansion effect. The studies focused on making the sample visually distinct. However, the response is restricted by limited thermal expansion coefficients. We herein report a new class of reversible thermochromic response achieved by controlling the ambient refractive index in butterfly PC structure. The photonic ethanol-filled nanoarchitecture sample is simply assembled by sealing liquid ethanol filling Papilio ulysses butterfly wing. Volatile ethanol is used to modulate the ambient refractive index. The sample is sealed with glasses to ensure reversibility. Liquid ethanol filling butterfly wing demonstrated significant allochroic response to ambient refractive index, which can be controlled by the liquefaction and vaporization of ethanol. This design is capable of converting thermal energy into visual color signals. The mechanism of this distinct response is simulated and proven by band theory. The response properties are performed with different filled chemicals and different structure parameters. Thus, the reversible thermochromic response design might have potential use in the fields such as detection, photonic switch, displays, and so forth.

All-optical diode structure based on asymmetrical coupling by a micro-cavity and FP cavity at two sides of photonic crystal waveguide

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

Liu, Bin, E-mail: liubin-d@126.com; Liu, Yun-Feng; He, Xing-Dao

2016-06-15

A high efficiency all-optical diode based on photonic crystal (PC) waveguide has been proposed and numerically investigated by finite-difference time-domain (FDTD) method. The structure is asymmetrically coupled by a micro-cavity containing nonlinear Kerr medium and a FP cavity at sides of PC waveguide. Because of interference between two cavities, Fano peak and FP peak can both appear in transmission spectra and unidirectional transmission can be achieved. The working wavelength can set between two peaks and near to the Fano peak. For forward launch with suitable light intensity, nonlinear Kerr effect of micro-cavity can been excited. It will result in redmore » shift of Fano peak and achieving forward transmission. But for backward launch, a stronger incidence light is needed to the excite Kerr effect due to the design of asymmetric structure. This design has many advantages, including high maximum transmittance, high transmittance contrast ratio, low power threshold, short response time, and ease of integration.« less

Dual-Responsive SPMA-Modified Polymer Photonic Crystals and Their Dynamic Display Patterns.

PubMed

Gao, Zewen; Gao, Dongsheng; Huang, Chao; Zhang, Hanbing; Guo, Jinbao; Wei, Jie

2018-05-28

Light and electrothermal responsive polymer photonic crystals (PCs) modified with 1'-acryloyl chloride-3',3'-dimethyl-6-nitro-spiro(2H-1-benzopyran-2,2'-indoline) (SPMA) are proposed, and their dynamic display patterns are achieved through the combination of the SPMA-modified PCs and a patterned graphite layer. These PCs exhibit fluorescence under UV light irradiation because of the isomerization of the SPMA, which is restricted in the shell of the polymer colloidal spheres. After a voltage is applied to the patterned graphite layer, the fluorescence of PCs in the specific area disappears, and dynamic display patterns are obtained. Under UV light irradiation, the PCs change from the "partial-fluorescence" state to the initial "fluorescence" state, and the patterns disappear. Using this technique, the PC pattern "M L N" on the glass substrate and PC patterns from "0" to "9" on the paper substrate are fabricated. Thus, these dual-responsive PCs have potential applications in information recording, anticounterfeiting, dynamic display, and photoelectric devices. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Factors Affecting Outcomes in Cochlear Implant Recipients Implanted With a Perimodiolar Electrode Array Located in Scala Tympani.

PubMed

Holden, Laura K; Firszt, Jill B; Reeder, Ruth M; Uchanski, Rosalie M; Dwyer, Noël Y; Holden, Timothy A

2016-12-01

To identify primary biographic and audiologic factors contributing to cochlear implant (CI) performance variability in quiet and noise by controlling electrode array type and electrode position within the cochlea. Although CI outcomes have improved over time, considerable outcome variability still exists. Biographic, audiologic, and device-related factors have been shown to influence performance. Examining CI recipients with consistent array type and electrode position may allow focused investigation into outcome variability resulting from biographic and audiologic factors. Thirty-nine adults (40 ears) implanted for at least 6 months with a perimodiolar electrode array known (via computed tomography [CT] imaging) to be in scala tympani participated. Test materials, administered CI only, included monosyllabic words, sentences in quiet and noise, and spectral ripple discrimination. In quiet, scores were high with mean word and sentence scores of 76 and 87%, respectively; however, sentence scores decreased by an average of 35 percentage points when noise was added. A principal components (PC) analysis of biographic and audiologic factors found three distinct factors, PC1 Age, PC2 Duration, and PC3 Pre-op Hearing. PC1 Age was the only factor that correlated, albeit modestly, with speech recognition in quiet and noise. Spectral ripple discrimination strongly correlated with speech measures. For these recipients with consistent electrode position, PC1 Age was related to speech recognition performance. Consistent electrode position may have contributed to high speech understanding in quiet. Inter-subject variability in noise may have been influenced by auditory/cognitive processing, known to decline with age, and mechanisms that underlie spectral resolution ability.

Responsive Photonic Crystal Carbohydrate Hydrogel Sensor Materials for Selective and Sensitive Lectin Protein Detection.

PubMed

Cai, Zhongyu; Sasmal, Aniruddha; Liu, Xinyu; Asher, Sanford A

2017-10-27

Lectin proteins, such as the highly toxic lectin protein, ricin, and the immunochemically important lectin, jacalin, play significant roles in many biological functions. It is highly desirable to develop a simple but efficient method to selectively detect lectin proteins. Here we report the development of carbohydrate containing responsive hydrogel sensing materials for the selective detection of lectin proteins. The copolymerization of a vinyl linked carbohydrate monomer with acrylamide and acrylic acid forms a carbohydrate hydrogel that shows specific "multivalent" binding to lectin proteins. The resulting carbohydrate hydrogels are attached to 2-D photonic crystals (PCs) that brightly diffract visible light. This diffraction provides an optical readout that sensitively monitors the hydrogel volume. We utilize lactose, galactose, and mannose containing hydrogels to fabricate a series of 2-D PC sensors that show strong selective binding to the lectin proteins ricin, jacalin, and concanavalin A (Con A). This binding causes a carbohydrate hydrogel shrinkage which significantly shifts the diffraction wavelength. The resulting 2-D PC sensors can selectively detect the lectin proteins ricin, jacalin, and Con A. These unoptimized 2-D PC hydrogel sensors show a limit of detection (LoD) of 7.5 × 10 -8 M for ricin, a LoD of 2.3 × 10 -7 M for jacalin, and a LoD of 3.8 × 10 -8 M for Con A, respectively. This sensor fabrication approach may enable numerous sensors for the selective detection of numerous lectin proteins.

Behavior of temperature-dependent dc-photoconductivity in hot-wall deposited CaAl2Se4 layers

NASA Astrophysics Data System (ADS)

Jeong, J. W.; Hong, K. J.; Jeong, T. S.; Youn, C. J.

2017-10-01

The dc-photoconductive characteristic on the hot-wall grown CaAl2Se4 (CAS) layers was explored as a function of temperature. From the photocurrent (PC) measurement, three PC peaks A, B, and C corresponded to the intrinsic transitions, which represent the band-to-band transitions from the valence-band states of Γ2(A), Γ3 + Γ4(B), and Γ3 + Γ4(C) to the conduction-band state of Γ1, respectively. Based on these PC results, the optical band-gap energy was well matched by E g ( T) = E g (0) - 4.94 × 10-3 T 2/( T + 552), where E g (0) is found to be 3.8239, 3.8716, and 3.8801 eV for three peaks A, B, and C, respectively. Thus, the effect of the crystal field and spin-orbit splitting (These values were extracted out to be 47.7 and 8.5 meV, respectively.) was observed and calculated by means of the PC spectroscopy. However, PC intensity gradually decreased with decreasing temperature unlike an ordinary behavior. In the log J ph vs 1/ T plot, two dominant traplevels were observed to be 20.81 meV at temperatures of 300 - 70 K and 1.18 meV at temperatures below 70 K. Consequently, we extract out that these trapping centers caused by native defects in CAS confine the PC intensity as temperature decreases.

Tetranuclear clusters containing a CrIII-doped MnIII4O2 core: syntheses, structures, and magnetic properties.

PubMed

Ma, Yun-Sheng; Li, Yi-Zhi; Song, You; Zheng, Li-Min

2008-06-02

The oxidation of MnII carboxylates by (NBu4)Cr2O7 in the presence of different phosphonic acids and chelating ligands results in six CrIII-doped tetranuclear manganese clusters formulated [Mn3CrO2(O2CCH3)4(O3PC5H4N)2(bpy)2] (1), [Mn3CrO2(O2CCH3)4(O3PC5H4N)2(phen)2] (2), [Mn3CrO2(O2CPh)4(O3PC5H4NO)2(phen)2] (3), [Mn3CrO2(O2CPh)4(O3PC6H11)2(bpy)2] (4), [Mn 3CrO2(O2CPh)4(O3PC6H11)2(phen) 2] (5), and [Mn3CrO2(O2CCH3)4(O3PC6H11)2(bpy)2] (6). Single-crystal X-ray analyses reveal that all the compounds contain similar [M4O2]8+ cores with the four metal sites arranged in planar topologies. The metal ions within the core are bridged by both carboxylate and phosphonate ligands. Temperature-dependent magnetic measurements show that in all cases dominant antiferromagnetic interactions are propagated between the metal centers. The ac magnetic measurements on compounds 5 and 6 reveal that both the in-phase and the out-of-phase signals are frequency dependent, characteristic of single-molecule magnet behaviors.

Controlled transition dipole alignment of energy donor and energy acceptor molecules in doped organic crystals, and the effect on intermolecular Förster energy transfer.

PubMed

Wang, Huan; Yue, Bailing; Xie, Zengqi; Gao, Bingrong; Xu, Yuanxiang; Liu, Linlin; Sun, Hongbo; Ma, Yuguang

2013-03-14

The orientation factor κ(2) ranging from 0 to 4, which depends on the relative orientation of the transition dipoles of the energy donor (D) and the energy acceptor (A) in space, is one of the pivotal factors deciding the efficiency and directionality of resonance energy transfer (RET) in a D-A molecular system. In this work, tetracene (Tc) and pentacene (Pc) are successfully doped in a trans-1,4-distyrylbenzene (DSB) crystalline lattice to form definite D-A mutually perpendicular transition dipole orientations. The cross D-A dipole arrangement results in an extremely small orientation factor, which is about two orders smaller than that in the disordered films. The energy transfer properties from the host (DSB) to the guest (Tc/Pc) were investigated in detail by steady-state as well as time-resolved fluorescence spectroscopy. Our experimental research results show that the small value of κ(2) allows less or partial energy transfer from the host (DSB) to the guest (Tc) in a wide range of guest concentration, with the Förster distance of around 1.5 nm. By controlling the doping concentrations in the Tc and Pc doubly doped DSB crystals, we demonstrate, as an example, for the first time the application of the restricted energy transfer by D-A cross transition dipole arrangement for preparation of a large-size, white-emissive organic crystal with the CIE coordinates of (0.36, 0.37) approaching an ideal white light. In contrast, Tc is also doped in an anthracene crystalline lattice to form head-to-tail D-A transition dipole alignment, which is proved to be highly effective to promote the intermolecular energy transfer. In this doped system, the orientation factor is relatively large and the Förster distance is around 7 nm.

Raw material variability of an active pharmaceutical ingredient and its relevance for processability in secondary continuous pharmaceutical manufacturing.

PubMed

Stauffer, F; Vanhoorne, V; Pilcer, G; Chavez, P-F; Rome, S; Schubert, M A; Aerts, L; De Beer, T

2018-06-01

Active Pharmaceutical Ingredients (API) raw material variability is not always thoroughly considered during pharmaceutical process development, mainly due to low quantities of drug substance available. However, synthesis, crystallization routes and production sites evolve during product development and product life cycle leading to changes in physical material attributes which can potentially affect their processability. Recent literature highlights the need for a global approach to understand the link between material synthesis, material variability, process and product quality. The study described in this article aims at explaining the raw material variability of an API using extensive material characterization on a restricted number of representative batches using multivariate data analysis. It is part of a larger investigation trying to link the API drug substance manufacturing process, the resulting physical API raw material attributes and the drug product continuous manufacturing process. Eight API batches produced using different synthetic routes, crystallization, drying, delumping processes and processing equipment were characterized, extensively. Seventeen properties from seven characterization techniques were retained for further analysis using Principal Component Analysis (PCA). Three principal components (PCs) were sufficient to explain 92.9% of the API raw material variability. The first PC was related to crystal length, agglomerate size and fraction, flowability and electrostatic charging. The second PC was driven by the span of the particle size distribution and the agglomerates strength. The third PC was related to surface energy. Additionally, the PCA allowed to summarize the API batch-to-batch variability in only three PCs which can be used in future drug product development studies to quantitatively evaluate the impact of the API raw material variability upon the drug product process. The approach described in this article could be applied to any other compound which is prone to batch-to-batch variability. Copyright © 2018 Elsevier B.V. All rights reserved.

Implementation of NCCN Palliative Care Guidelines by member institutions.

PubMed

Albizu-Rivera, Alexandra; Portman, Diane G; Thirlwell, Sarah; Codada, Shirley N; Donovan, Kristine A

2016-02-01

Increasingly, evidence suggests the integration of palliative care (PC) with standard oncologic care can yield substantial benefits. As part of an effort to improve the PC of cancer patients, the National Comprehensive Cancer Network (NCCN) has developed clinical practice guidelines for PC that promote access to quality, evidence-based PC. This study sought to characterize current implementation of the guidelines by NCCN member institutions. Institutional representatives appointed to the NCCN Palliative Care Guidelines Panel were asked to complete an online survey in the spring of 2014. The survey focused on availability of PC services, screening and referral practices for PC, PC education, and quality improvement programs. The survey was completed by representatives from 21 of 25 NCCN member institutions (84 %). A majority routinely provides PC services via interdisciplinary teams; 52 % routinely inform patients of the availability, elements, and benefits of PC. The guidelines are most often used to guide clinical practice; only 10 % reported using the guidelines to formally screen for PC needs and/or make referrals to PC specialists. Among the 62 % of institutions that screen any patients using any available criteria, when a patient screens positive for PC needs, a referral to a PC specialist is made less than half the time. Implementation of PC Guidelines is incomplete and various aspects of the guidelines, such as the recommendation to screen all patients for PC needs, are applied inconsistently. Despite this, most institutions provide PC services in a manner consistent with the guidelines. Greater implementation of the guidelines' recommendations is needed.

Divergent prion strain evolution driven by PrPC expression level in transgenic mice

PubMed Central

Le Dur, Annick; Laï, Thanh Lan; Stinnakre, Marie-George; Laisné, Aude; Chenais, Nathalie; Rakotobe, Sabine; Passet, Bruno; Reine, Fabienne; Soulier, Solange; Herzog, Laetitia; Tilly, Gaëlle; Rézaei, Human; Béringue, Vincent; Vilotte, Jean-Luc; Laude, Hubert

2017-01-01

Prions induce a fatal neurodegenerative disease in infected host brain based on the refolding and aggregation of the host-encoded prion protein PrPC into PrPSc. Structurally distinct PrPSc conformers can give rise to multiple prion strains. Constrained interactions between PrPC and different PrPSc strains can in turn lead to certain PrPSc (sub)populations being selected for cross-species transmission, or even produce mutation-like events. By contrast, prion strains are generally conserved when transmitted within the same species, or to transgenic mice expressing homologous PrPC. Here, we compare the strain properties of a representative sheep scrapie isolate transmitted to a panel of transgenic mouse lines expressing varying levels of homologous PrPC. While breeding true in mice expressing PrPC at near physiological levels, scrapie prions evolve consistently towards different strain components in mice beyond a certain threshold of PrPC overexpression. Our results support the view that PrPC gene dosage can influence prion evolution on homotypic transmission. PMID:28112164

The reliability paradox of the Parent-Child Conflict Tactics Corporal Punishment Subscale.

PubMed

Lorber, Michael F; Slep, Amy M Smith

2018-02-01

In the present investigation we consider and explain an apparent paradox in the measurement of corporal punishment with the Parent-Child Conflict Tactics Scale (CTS-PC): How can it have poor internal consistency and still be reliable? The CTS-PC was administered to a community sample of 453 opposite sex couples who were parents of 3- to 7-year-old children. Internal consistency was marginal, yet item response theory analyses revealed that reliability rose sharply with increasing corporal punishment, exceeding .80 in the upper ranges of the construct. The results suggest that the CTS-PC Corporal Punishment subscale reliably discriminates among parents who report average to high corporal punishment (64% of mothers and 56% of fathers in the present sample), despite low overall internal consistency. These results have straightforward implications for the use and reporting of the scale. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Charge transfer complexes of metal-free phthalocyanine radical anions with decamethylmetallocenium cations: (Cp*2Co+)(H2Pc˙-)·solvent and (Cp*2Cr+)(H2Pc˙-)·4C6H4Cl2.

PubMed

Konarev, Dmitri V; Khasanov, Salavat S; Ishikawa, Manabu; Otsuka, Akihiro; Yamochi, Hideki; Saito, Gunzi; Lyubovskaya, Rimma N

2017-03-14

Charge transfer complexes (Cp* 2 Co + )(H 2 Pc˙ - )·0.5C 6 H 4 Cl 2 ·0.7C 6 H 5 CN·0.3C 6 H 14 (1) and (Cp* 2 Cr + )(H 2 Pc˙ - )·4C 6 H 4 Cl 2 (2) have been obtained as single crystals. Both complexes contain metal-free phthalocyanine (Pc) radical anions and decamethylmetallocenium cations. Reduction of the Pc macrocycle leads to the appearance of new bands at 1026-1030 nm in the NIR range and blue shifts of both Soret and Q-bands of H 2 Pc in the spectra of 1 and 2. The geometry of the Pc macrocycles supports the formation of H 2 Pc˙ - by the alternation of shorter and longer C-N(imine) bonds in the macrocycles in 2. Complex 1 contains pairs of H 2 Pc˙ - having effective π-π interactions with two sandwiched Cp* 2 Co + cations, whereas complex 2 contains stacks composed of alternating Cp* 2 Cr + and H 2 Pc˙ - ions. The magnetic moment of 1 is 1.64 μ B at 300 K due to the contribution of the H 2 Pc˙ - spins with the S = 1/2 state and diamagnetism of Cp* 2 Co + . This is supported by the observation of a narrow EPR signal of 1 with g = 2.0032-2.0036 characteristic of H 2 Pc˙ - . Strong antiferromagnetic coupling of spins with a Weiss temperature of -23 K is observed between H 2 Pc˙ - in 1. This coupling is probably mediated by the Cp* 2 Co + cations. The magnetic moment of 2 is 4.18 μ B at 300 K indicating the contribution of both paramagnetic H 2 Pc˙ - (S = 1/2) and Cp* 2 Cr + (S = 3/2) species. In spite of the presence of stacks of alternating ions in 2, only weak magnetic coupling is observed with a Weiss temperature of -4 K most probably due to ineffective π-π interactions between Cp* 2 Cr + and H 2 Pc˙ - . The EPR spectrum of 2 contains an asymmetric signal attributed to Cr III (g 1 = 3.9059-3.9220) and a narrow Lorentzian signal from H 2 Pc˙ - with g 2 = 1.9943-1.9961. In addition to these signals, a broad EPR signal grows in intensity below 80 K with g 4 = 2.1085-2.2438 which can be attributed to both paramagnetic Cp* 2 Cr + and H 2 Pc˙ - species having exchange interactions.

Negative refraction of acoustic waves using a foam-like metallic structure

NASA Astrophysics Data System (ADS)

Hladky-Hennion, A.-C.; Vasseur, J. O.; Haw, G.; Croënne, C.; Haumesser, L.; Norris, A. N.

2013-04-01

A phononic crystal (PC) slab made of a single metallic phase is shown, theoretically and experimentally, to display perfect negative index matching and focusing capability when surrounded with water. The proposed PC slab is a centimeter scale hollow metallic foam-like structure in which acoustic energy is mediated via the metal lattice. The negative index property arises from an isolated branch of the dispersion curves corresponding to a mode that can be coupled to incident acoustic waves in surrounding water. This band also intercepts the water sound line at a frequency in the ultrasonic range. The metallic structure is consequently a candidate for the negative refraction of incident longitudinal waves.

Characterization of LiBC by phase-contrast scanning transmission electron microscopy.

PubMed

Krumeich, Frank; Wörle, Michael; Reibisch, Philipp; Nesper, Reinhard

2014-08-01

LiBC was used as a model compound for probing the applicability of phase-contrast (PC) imaging in an aberration-corrected scanning transmission electron microscope (STEM) to visualize lithium distributions. In the LiBC structure, boron and carbon are arranged to hetero graphite layers between which lithium is incorporated. The crystal structure is reflected in the PC-STEM images recorded perpendicular to the layers. The experimental images and their defocus dependence match with multi-slice simulations calculated utilizing the reciprocity principle. The observation that a part of the Li positions is not occupied is likely an effect of the intense electron beam triggering Li displacement. Copyright © 2013 Elsevier Ltd. All rights reserved.

Hydrogen And Deuterium In The Local Interstellar Medium.

NASA Astrophysics Data System (ADS)

Murthy, Jayant

2016-03-01

In this work we report on the results of a series of IUE observations of interstellar HI and DI Ly alpha absorption against the chromospheric Lyalpha emission of the nearby late -type stars alpha Cen B(1.3 pc), epsilon Eri (3.3 pc), Procyon (3.5 pc), Altair (5.1 pc), Capella (13.2 pc), and HR 1099 (33 pc). From these observations we have derived the density, velocity dispersion, and bulk velocity of the neutral hydrogen along the line of sight to each of these stars. We have also placed lower limits on the deuterium to hydrogen (D/H) ratio towards the same stars. Our IUE results are generally consistent with previous observations of the same stars with the Copernicus satellite showing that our modelling procedure is independent of stellar variations over a period of several years. The HI absorption profile towards Altair shows a broad saturated core and steep line wings, consistent with a multicomponent interstellar medium in that direction. The bulk velocities towards the other stars are consistent with a bulk flow from the approximate direction of the galactic center but do show local variations from a uniform flow, possibly indicating a complicated velocity structure even in the solar neighbourhood. Interstellar deuterium is detected towards every star except Altair and the derived values for the D/H ratio are consistent with those previously found with Copernicus. In particular, we confirm the strong lower limit of 1.9 times 10^{-5} on the D/H ratio found towards Capella and we also place a lower limit of 1.5 times 10 ^{-5} on the D/H ratio towards alpha Cen B. Although an interstellar D/H ratio of 2 times 10^ {-5} is consistent with all the observations of late-type stars, the lower D/H ratios found towards several hot stars may indicate real variations in the D/H ratio in the local interstellar medium. Finally, we discuss the reality of a step in the cosmic background and of several galactic emission lines found by Auriemma et al. (1984) and show that, in fact, they are both artifacts of the data and of the analysis.

Spatially selective photonic crystal enhanced fluorescence and application to background reduction for biomolecule detection assays

PubMed Central

Chaudhery, Vikram; Huang, Cheng-Sheng; Pokhriyal, Anusha; Polans, James; Cunningham, Brian T.

2011-01-01

By combining photonic crystal label-free biosensor imaging with photonic crystal enhanced fluorescence, it is possible to selectively enhance the fluorescence emission from regions of the PC surface based upon the density of immobilized capture molecules. A label-free image of the capture molecules enables determination of optimal coupling conditions of the laser used for fluorescence imaging of the photonic crystal surface on a pixel-by-pixel basis, allowing maximization of fluorescence enhancement factor from regions incorporating a biomolecule capture spot and minimization of background autofluorescence from areas between capture spots. This capability significantly improves the contrast of enhanced fluorescent images, and when applied to an antibody protein microarray, provides a substantial advantage over conventional fluorescence microscopy. Using the new approach, we demonstrate detection limits as low as 0.97 pg/ml for a representative protein biomarker in buffer. PMID:22109210

Spatially selective photonic crystal enhanced fluorescence and application to background reduction for biomolecule detection assays.

PubMed

Chaudhery, Vikram; Huang, Cheng-Sheng; Pokhriyal, Anusha; Polans, James; Cunningham, Brian T

2011-11-07

By combining photonic crystal label-free biosensor imaging with photonic crystal enhanced fluorescence, it is possible to selectively enhance the fluorescence emission from regions of the PC surface based upon the density of immobilized capture molecules. A label-free image of the capture molecules enables determination of optimal coupling conditions of the laser used for fluorescence imaging of the photonic crystal surface on a pixel-by-pixel basis, allowing maximization of fluorescence enhancement factor from regions incorporating a biomolecule capture spot and minimization of background autofluorescence from areas between capture spots. This capability significantly improves the contrast of enhanced fluorescent images, and when applied to an antibody protein microarray, provides a substantial advantage over conventional fluorescence microscopy. Using the new approach, we demonstrate detection limits as low as 0.97 pg/ml for a representative protein biomarker in buffer.

Enhanced superconductivity at the interface of W/Sr2RuO4 point contact

NASA Astrophysics Data System (ADS)

Wei, Jian; Wang, He; Lou, Weijian; Luo, Jiawei; Liu, Ying; Ortmann, J. E.; Mao, Z. Q.

Differential resistance measurements are conducted for point contacts (PCs) between the Sr2RuO4 (SRO) single crystal and the tungsten tip. Since the tungsten tip is hard enough to penetrate through the surface layer, consistent superconducting features are observed. Firstly, with the tip pushed towards the crystal, the zero bias conductance peak (ZBCP) due to Andreev reflection at the normal-superconducting interface increases from 3% to more than 20%, much larger than previously reported, and extends to temperature higher than the bulk transition temperature. Reproducible ZBCP within 0.2 mV may also help determine the gap value of SRO, on which no consensus has been reached. Secondly, the logarithmic background can be fitted with the Altshuler-Aronov theory of electron-electron interaction for tunneling into quasi two dimensional electron system. Feasibility of such fitting confirms that spectroscopic information like density of states is probed, and electronic temperature retrieved from such fitting can be important to analyse the PC spectra. Third, at bias much higher than 0.2 mV there are conductance dips due to the critical current effect and these dips persist up to 6.2 K. For more details see. National Basic Research Program of China (973 Program) through Grant No. 2011CBA00106 and No. 2012CB927400.

14 CFR Appendix C to Part 187 - Fees for Production Certification-Related Services Performed Outside the United States

Code of Federal Regulations, 2011 CFR

2011-01-01

... consist of: personnel compensation and benefit (PC&B) for each participating FAA employee, actual travel...: W1H1+ W2H2 etc., + T + O Where: W1H1=hourly PC&B rate for employee 1, times estimated hours W2H2=hourly PC&B rate for employee 2, etc., times estimated hours T=estimated travel and transportation expenses...

14 CFR Appendix C to Part 187 - Fees for Production Certification-Related Services Performed Outside the United States

Code of Federal Regulations, 2010 CFR

2010-01-01

... consist of: personnel compensation and benefit (PC&B) for each participating FAA employee, actual travel...: W1H1+ W2H2 etc., + T + O Where: W1H1=hourly PC&B rate for employee 1, times estimated hours W2H2=hourly PC&B rate for employee 2, etc., times estimated hours T=estimated travel and transportation expenses...

Comparative characterisation of the biofilm-production abilities of Staphylococcus epidermidis isolated from human skin and platelet concentrates.

PubMed

Taha, Mariam; Kohnen, Carissa; Mallya, Shruti; Kou, Yuntong; Zapata, Adriana; Ramirez-Arcos, Sandra

2018-02-01

Staphylococcus epidermidis is the predominant contaminant of platelet concentrates (PCs), a blood product used to treat patients with platelet deficiencies. This microorganism is able to form surface-attached aggregates (biofilms) in human skin. Herein, the abundance of S. epidermidis biofilm-producers in contaminated PCs compared to skin isolates was explored. Furthermore, the potential positive selection of S. epidermidis biofilm-producers during the blood donation process and PC manufacturing was investigated. Twenty-four S. epidermidis isolates obtained from contaminated PCs and 48 S. epidermidis isolates obtained from the venipuncture area of human volunteers were compared for their ability to form biofilms in laboratory media and in PCs using a semi quantitative crystal violet assay. Also, the presence of the biofilm-associated icaA and icaD genes was assessed by PCR-amplification.Results/Key findings.Biofilm production in laboratory media showed a higher number of S. epidermidis biofilm-producers in the skin-derived group (43.7 %) compared to the PC-derived isolates (25 %). However, all skin and PC isolates formed biofilms in PCs. The prevalence of ica-positive biofilm-producer isolates was similar in PC and skin isolates (16.6 and 18.8 %, respectively). In contrast, the abundance of ica-negative biofilm-producers was lower in PC isolates compared to skin isolates (8.3 vs 25 %, respectively). Positive selection of S. epidermidis biofilm-producers during blood donation and PC manufacturing was not observed. Interestingly, ica-negative biofilm-producers seem to be negatively affected by skin disinfection, blood processing and PC storage. Furthermore, this study shows that S. epidermidis adopts a biofilm-forming phenotype in PCs regardless of its genetic background or origin.

How Many Alternatives Can Be Ranked? A Comparison of the Paired Comparison and Ranking Methods.

PubMed

Ock, Minsu; Yi, Nari; Ahn, Jeonghoon; Jo, Min-Woo

2016-01-01

To determine the feasibility of converting ranking data into paired comparison (PC) data and suggest the number of alternatives that can be ranked by comparing a PC and a ranking method. Using a total of 222 health states, a household survey was conducted in a sample of 300 individuals from the general population. Each respondent performed a PC 15 times and a ranking method 6 times (two attempts of ranking three, four, and five health states, respectively). The health states of the PC and the ranking method were constructed to overlap each other. We converted the ranked data into PC data and examined the consistency of the response rate. Applying probit regression, we obtained the predicted probability of each method. Pearson correlation coefficients were determined between the predicted probabilities of those methods. The mean absolute error was also assessed between the observed and the predicted values. The overall consistency of the response rate was 82.8%. The Pearson correlation coefficients were 0.789, 0.852, and 0.893 for ranking three, four, and five health states, respectively. The lowest mean absolute error was 0.082 (95% confidence interval [CI] 0.074-0.090) in ranking five health states, followed by 0.123 (95% CI 0.111-0.135) in ranking four health states and 0.126 (95% CI 0.113-0.138) in ranking three health states. After empirically examining the consistency of the response rate between a PC and a ranking method, we suggest that using five alternatives in the ranking method may be superior to using three or four alternatives. Copyright © 2016 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

Osteopontin splice variants expression is involved on docetaxel resistance in PC3 prostate cancer cells.

PubMed

Nakamura, K D M; Tilli, T M; Wanderley, J L; Palumbo, A; Mattos, R M; Ferreira, A C; Klumb, C E; Nasciutti, L E; Gimba, E R

2016-02-01

Osteopontin (OPN) is a phosphoprotein that activates several aspects of tumor progression. Alternative splicing of the OPN primary transcript generates three splicing isoforms, OPNa, OPNb and OPNc. In this report, we investigated some cellular mechanisms by which OPN splice variants could mediate PC3 prostate cancer (PCa) cell survival and growth in response to docetaxel (DXT)-induced cell death. Cell survival before and after DXT treatment was analyzed by phase-contrast microscopy and crystal-violet staining assays. Quantitative real-time PCR and immunocytochemical staining assays were used to evaluate the putative involvement of epithelial-mesenchymal transition (EMT) and OPN isoforms on mediating PC3 cell survival. Upon DXT treatment, PC3 cells overexpressing OPNb or OPNc isoforms showed higher cell densities, compared to cells overexpressing OPNa and controls. Notably, cells overexpressing OPNb or OPNc isoforms showed a downregulated pattern of EMT epithelial cell markers, while mesenchymal markers were mostly upregulated in these experimental conditions. We concluded that OPNc or OPNb overexpression in PC3 cells can mediate resistance and cell survival features in response to DXT-induced cell death. Our data also provide evidence the EMT program could be one of the molecular mechanisms mediating survival in OPNb- or OPNc-overexpressing cells in response to DXT treatment. These data could further contribute to a better understanding of the mechanisms by which PCa cells acquire resistance to DXT treatment.

Dynamics of photogenerated nonequilibrium electronic states in Ar+-ion-irradiated SrTiO3

NASA Astrophysics Data System (ADS)

Kumar, Dushyant; Hossain, Z.; Budhani, R. C.

2015-05-01

A metallic surface is realized on stoichiometric and insulating (100) SrTiO3 by Ar+-ion irradiation. The sheet carrier density and Hall mobility of the layer are ˜4.0 ×1014cm-2 and ˜2 ×103cm2/Vs , respectively, at 15 K for the irradiation dose of ˜4.2 ×1018ions/cm2 . These samples display ultraviolet light sensitive photoconductivity (PC) which is enhanced abruptly below the temperature (≈100 K) where SrTiO3 crystal undergoes an antiferrodistortive cubic-to-tetragonal (Oh1→D4h 18 ) structural phase transition. This behavior of PC maps well with the temperature dependence of dielectric function and electric field induced conductivity. The longevity of the PC state also shows a distinct change below ≈100 K. At T >100 K its decay is thermally activated with an energy barrier of ≈36 meV, whereas at T <100 K it becomes independent of temperature. We have examined the effect of electrostatic gating on the lifetime of the PC state. One nontrivial result is the ambient temperature quenching of the photoconducting state by the negative gate field. This observation opens avenues for designing a solid state photoelectric switch. The origin and lifetime of the PC state are understood in the light of field effect induced band bending, defect dynamics, and thermal relaxation processes.

Retromer associates with the cytoplasmic amino-terminus of polycystin-2.

PubMed

Tilley, Frances C; Gallon, Matthew; Luo, Chong; Danson, Chris M; Zhou, Jing; Cullen, Peter J

2018-05-03

Autosomal dominant polycystic kidney disease (ADPKD) is the most common monogenic human disease, with around 12.5 million people affected worldwide. ADPKD results from mutations in either PKD1 or PKD2 , which encode the atypical G-protein coupled receptor polycystin-1 (PC1) and the transient receptor potential channel polycystin-2 (PC2) respectively. Although altered intracellular trafficking of PC1 and PC2 appear as an underlying feature of ADPKD, the mechanisms which govern vesicular transport of the polycystins through the biosynthetic and endosomal membrane networks remain to be fully elucidated. Here, we describe an interaction between PC2 and retromer, a master controller for the sorting of integral membrane proteins through the endo-lysosomal network. We show that association of PC2 with retromer occurs via a region in the PC2 cytoplasmic amino-terminal domain, independently of the retromer-binding Wiskott-Aldrich syndrome and scar homologue (WASH) complex. Based on observations that retromer preferentially interacts with a trafficking population of PC2, and that ciliary levels of PC1 are reduced upon mutation of key residues required for retromer-association in PC2, our data is consistent with the identification of PC2 as a retromer cargo protein. © 2018. Published by The Company of Biologists Ltd.

Orthotopic Patient-Derived Pancreatic Cancer Xenografts Engraft Into the Pancreatic Parenchyma, Metastasize, and Induce Muscle Wasting to Recapitulate the Human Disease.

PubMed

Go, Kristina L; Delitto, Daniel; Judge, Sarah M; Gerber, Michael H; George, Thomas J; Behrns, Kevin E; Hughes, Steven J; Judge, Andrew R; Trevino, Jose G

2017-07-01

Limitations associated with current animal models serve as a major obstacle to reliable preclinical evaluation of therapies in pancreatic cancer (PC). In an effort to develop more reliable preclinical models, we have recently established a subcutaneous patient-derived xenograft (PDX) model. However, critical aspects of PC responsible for its highly lethal nature, such as the development of distant metastasis and cancer cachexia, remain underrepresented in the flank PDX model. The purpose of this study was to evaluate the degree to which an orthotopic PDX model of PC recapitulates these aspects of the human disease. Human PDX-derived PC tumors were implanted directly into the pancreas of NOD.Cg-Prkdc Il2rg/SzJ mice. Tumor growth, metastasis, and muscle wasting were then evaluated. Orthotopically implanted PDX-derived tumors consistently incorporated into the murine pancreatic parenchyma, metastasized to both the liver and lungs and induced muscle wasting directly proportional to the size of the tumor, consistent of the cancer cachexia syndrome. Through the orthotopic implantation technique described, we demonstrate a highly reproducible model that recapitulates both local and systemic aspects of human PC.

Modulation of Bacillus thuringiensis Phosphatidylinositol-Specific Phospholipase C Activity by Mutations in the Putative Dimerization Interface

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

Shi, X.; Shao, C; Zhang, X

2009-01-01

Cleavage of phosphatidylinositol (PI) to inositol 1,2-(cyclic)-phosphate (cIP) and cIP hydrolysis to inositol 1-phosphate by Bacillus thuringiensis phosphatidylinositol-specific phospholipase C are activated by the enzyme binding to phosphatidylcholine (PC) surfaces. Part of this reflects improved binding of the protein to interfaces. However, crystallographic analysis of an interfacially impaired phosphatidylinositol-specific phospholipase (W47A/W242A) suggested protein dimerization might occur on the membrane. In the W47A/W242A dimer, four tyrosine residues from one monomer interact with the same tyrosine cluster of the other, forming a tight dimer interface close to the membrane binding regions. We have constructed mutant proteins in which two or more ofmore » these tyrosine residues have been replaced with serine. Phospholipid binding and enzymatic activity of these mutants have been examined to assess the importance of these residues to enzyme function. Replacing two tyrosines had small effects on enzyme activity. However, removal of three or four tyrosine residues weakened PC binding and reduced PI cleavage by the enzyme as well as PC activation of cIP hydrolysis. Crystal structures of Y247S/Y251S in the absence and presence of myo-inositol as well as Y246S/Y247S/Y248S/Y251S indicate that both mutant proteins crystallized as monomers, were very similar to one another, and had no change in the active site region. Kinetic assays, lipid binding, and structural results indicate that either (i) a specific PC binding site, critical for vesicle activities and cIP activation, has been impaired, or (ii) the reduced dimerization potential for Y246S/Y247S/Y248S and Y246S/Y247S/Y248S/Y251S is responsible for their reduced catalytic activity in all assay systems.« less

Enhancing the bioavailability of mebendazole by integrating the principles solid dispersion and nanocrystal techniques, for safe and effective management of human echinococcosis.

PubMed

Chaudhary, Sushant; Garg, Tarun; Rath, Goutam; Murthy, Rs Rayasa; Goyal, Amit K

2016-05-01

The method based on integrating the principles of solid dispersion and nanocrystal techniques was developed to prepare polymer crystals (PCs) of mebendazole (MBZ) and polyethylene glycol (PEG). Powder X-Ray diffraction (PXRD) of the PC crystals shows the required integrated crystalline and amorphous regions. The in vitro solubility studies showed a 32-fold increase in the solubility of the drug. Tests of dissolution of the PCs showed that the crystals have an enhanced dissolution rate in comparison to those in the MF. The results of the pharmacokinetic study showed a 2.12-fold increase in the bioavailability of the drug. Thus, the present study has proved the potential in enhancing solubility, dissolution, and bioavailability of the drug.

Molecular resolution friction microscopy of Cu phthalocyanine thin films on dolomite (104) in water

NASA Astrophysics Data System (ADS)

Nita, Paweł; Pimentel, Carlos; Luo, Feng; Milián-Medina, Begoña; Gierschner, Johannes; Pina, Carlos M.; Gnecco, Enrico

2014-06-01

The reliability of ultrathin organic layers as active components for molecular electronic devices depends ultimately on an accurate characterization of the layer morphology and ability to withstand mechanical stresses on the nanoscale. To this end, since the molecular layers need to be electrically decoupled using thick insulating substrates, the use of AFM becomes mandatory. Here, we show how friction force microscopy (FFM) in water allows us to identify the orientation of copper(ii)phthalocyanine (CuPc) molecules previously self-assembled on a dolomite (104) mineral surface in ultra-high vacuum. The molecular features observed in the friction images show that the CuPc molecules are stacked in parallel rows with no preferential orientation with respect to the dolomite lattice, while the stacking features resemble well the single CuPc crystal structure. This proves that the substrate induction is low and makes friction force microscopy in water a suitable alternative to more demanding dynamic AFM techniques in ultra-high vacuum.

Molecular resolution friction microscopy of Cu phthalocyanine thin films on dolomite (104) in water.

PubMed

Nita, Paweł; Pimentel, Carlos; Luo, Feng; Milián-Medina, Begoña; Gierschner, Johannes; Pina, Carlos M; Gnecco, Enrico

2014-07-21

The reliability of ultrathin organic layers as active components for molecular electronic devices depends ultimately on an accurate characterization of the layer morphology and ability to withstand mechanical stresses on the nanoscale. To this end, since the molecular layers need to be electrically decoupled using thick insulating substrates, the use of AFM becomes mandatory. Here, we show how friction force microscopy (FFM) in water allows us to identify the orientation of copper(ii)phthalocyanine (CuPc) molecules previously self-assembled on a dolomite (104) mineral surface in ultra-high vacuum. The molecular features observed in the friction images show that the CuPc molecules are stacked in parallel rows with no preferential orientation with respect to the dolomite lattice, while the stacking features resemble well the single CuPc crystal structure. This proves that the substrate induction is low and makes friction force microscopy in water a suitable alternative to more demanding dynamic AFM techniques in ultra-high vacuum.

EPR study of a gamma-irradiated (2-hydroxyethyl)triphenylphosphonium chloride single crystal

NASA Astrophysics Data System (ADS)

Karakaş, E.; Türkkan, E.; Dereli, Ö.; Sayιn, Ü.; Tapramaz, R.

2011-12-01

In this study, gamma-irradiated single crystals of (2-hydroxyethyl)triphenylphosphonium chloride [CH2CH2OH P(C6H5)3Cl] were investigated with electron paramagnetic resonance (EPR) spectroscopy at room temperature for different orientations in the magnetic field. The single crystals were irradiated with a 60Co-γ-ray source at 0.818 kGy/h for about 36 h. Taking the chemical structure and the experimental spectra of the irradiated single crystal of the title compound into consideration, a paramagnetic species was produced with the unpaired electron delocalized around 31P and several 1H nuclei. The anisotropic hyperfine values due to the 31P nucleus, slightly anisotropic hyperfine values due to the 1H nuclei and the g-tensor of the radical were measured from the spectra. Depending on the molecular structure and measured parameters, three possible radicals were modeled using the B3LYP/6-31+G(d) level of density-functional theory, and EPR parameters were calculated for modeled radicals using the B3LYP/TZVP method/basis set combination. The calculated hyperfine coupling constants were found to be in good agreement with the observed EPR parameters. The experimental and theoretically simulated spectra for each of the three crystallographic axes were well matched with one of the modeled radicals (discussed in the text). We thus identified the radical C˙H2CH2 P(C 6H5)3 Cl as a paramagnetic species produced in a single crystal of the title compound in two magnetically distinct sites. The experimental g-factor and hyperfine coupling constants of the radical were found to be anisotropic, with the isotropic values g iso = 2.0032, ? G, ? G, ? G and ? G for site 1 and g iso=2.0031, ? G, ? G ? G and ? G for site 2.

Influence of "in series" elastic resistance on muscular performance during a biceps-curl set on the cable machine.

PubMed

García-López, David; Herrero, Azael J; González-Calvo, Gustavo; Rhea, Matthew R; Marín, Pedro J

2010-09-01

This study aimed to investigate the role of elastic resistance (ER) applied "in series" to a pulley-cable (PC) machine on the number of repetitions performed, kinematics parameters, and perceived exertion during a biceps-curl set to failure with a submaximal load (70% of the 1 repetition maximum). Twenty-one undergraduate students (17 men and 4 women) performed, on 2 different days, 1 biceps-curl set on the PC machine. Subjects were randomly assigned to complete 2 experimental conditions in a cross-over fashion: conventional PC mode or ER + PC mode. Results indicate ER applied "in series" to a PC machine significantly reduces (p < 0.05) the maximal number of repetitions and results in a smooth and consistent decline in mean acceleration throughout the set, in comparison to the conventional PC mode. Although no significant differences were found concerning intrarepetition kinematics, the ER trended to reduce (18.6%) the peak acceleration of the load. With a more uniformly distributed external resistance, a greater average muscle tension could have been achieved throughout the range of movement, leading to greater fatigue that could explain the lower number of maximal repetitions achieved. The application of force in a smooth, consistent fashion during each repetition of an exercise, while avoiding active deceleration, is expected to enhance the benefits of the resistance exercise, especially for those seeking greater increases in muscular hypertrophy.

Quasi-Chemical PC-SAFT: An Extended Perturbed Chain-Statistical Associating Fluid Theory for Lattice-Fluid Mixtures.

PubMed

Parvaneh, Khalil; Shariati, Alireza

2017-09-07

In this study, a new modification of the perturbed chain-statistical associating fluid theory (PC-SAFT) has been proposed by incorporating the lattice fluid theory of Guggenheim as an additional term to the original PC-SAFT terms. As the proposed model has one more term than the PC-SAFT, a new mixing rule has been developed especially for the new additional term, while for the conventional terms of the PC-SAFT, the one-fluid mixing rule is used. In order to evaluate the proposed model, the vapor-liquid equilibria were estimated for binary CO 2 mixtures with 16 different ionic liquids (ILs) of the 1-alkyl-3-methylimidazolium family with various anions consisting of bis(trifluoromethylsulfonyl) imide, hexafluorophosphate, tetrafluoroborate, and trifluoromethanesulfonate. For a comprehensive comparison, three different modes (different adjustable parameters) of the proposed model were compared with the conventional PC-SAFT. Results indicate that the proposed modification of the PC-SAFT EoS is generally more reliable with respect to the conventional PC-SAFT in all the three proposed modes of vapor-liquid equilibria, giving good agreement with literature data.

Cloning and heterologous expression of two aryl-aldehyde dehydrogenases from the white-rot basidiomycete Phanerochaete chrysosporium

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

Nakamura, Tomofumi; Fukuoka Institute of Health and Environmental Sciences, 39 Mukaizano, Dazaifu-shi, Fukuoka 818-0135; Ichinose, Hirofumi

2010-04-09

We identified two aryl-aldehyde dehydrogenase proteins (PcALDH1 and PcALDH2) from the white-rot basidiomycete Phanerochaete chrysosporium. Both PcALDHs were translationally up-regulated in response to exogenous addition of vanillin, one of the key aromatic compounds in the pathway of lignin degradation by basidiomycetes. To clarify the catalytic functions of PcALDHs, we isolated full-length cDNAs encoding these proteins and heterologously expressed the recombinant enzymes using a pET/Escherichia coli system. The open reading frames of both PcALDH1 and PcALDH2 consisted of 1503 nucleotides. The deduced amino acid sequences of both proteins showed high homologies with aryl-aldehyde dehydrogenases from other organisms and contained ten conservedmore » domains of ALDHs. Moreover, a novel glycine-rich motif 'GxGxxxG' was located at the NAD{sup +}-binding site. The recombinant PcALDHs catalyzed dehydrogenation reactions of several aryl-aldehyde compounds, including vanillin, to their corresponding aromatic acids. These results strongly suggested that PcALDHs metabolize aryl-aldehyde compounds generated during fungal degradation of lignin and various aromatic xenobiotics.« less

Synthesis, structures, and properties of crystalline salts with radical anions of metal-containing and metal-free phthalocyanines.

PubMed

Konarev, Dmitri V; Kuzmin, Alexey V; Faraonov, Maxim A; Ishikawa, Manabu; Khasanov, Salavat S; Nakano, Yoshiaki; Otsuka, Akihiro; Yamochi, Hideki; Saito, Gunzi; Lyubovskaya, Rimma N

2015-01-12

Radical anion salts of metal-containing and metal-free phthalocyanines [MPc(3-)](·-), where M = Cu(II), Ni(II), H2, Sn(II), Pb(II), Ti(IV)O, and V(IV)O (1-10) with tetraalkylammonium cations have been obtained as single crystals by phthalocyanine reduction with sodium fluorenone ketyl. Their formation is accompanied by the Pc ligand reduction and affects the molecular structure of metal phthalocyanine radical anions as well as their optical and magnetic properties. Radical anions are characterized by the alternation of short and long C-Nimine bonds in the Pc ligand owing to the disruption of its aromaticity. Salts 1-10 show new bands at 833-1041 nm in the NIR range, whereas the Q- and Soret bands are blue-shifted by 0.13-0.25 eV (38-92 nm) and 0.04-0.07 eV (4-13 nm), respectively. Radical anions with Ni(II), Sn(II), Pb(II), and Ti(IV)O have S = 1/2 spin state, whereas [Cu(II)Pc(3-)](·-) and [V(IV)OPc(3-)](·-) containing paramagnetic Cu(II) and V(IV)O have two S = 1/2 spins per radical anion. Central metal atoms strongly affect EPR spectra of phthalocyanine radical anions. Instead of narrow EPR signals characteristic of metal-free phthalocyanine radical anions [H2Pc(3-)](·-) (linewidth of 0.08-0.24 mT), broad EPR signals are manifested (linewidth of 2-70 mT) with g-factors and linewidths that are strongly temperature-dependent. Salt 11 containing the [Na(I)Pc(2-)](-) anions as well as previously studied [Fe(I)Pc(2-)](-) and [Co(I)Pc(2-)](-) anions that are formed without reduction of the Pc ligand do not show changes in molecular structure or optical and magnetic properties characteristic of [MPc(3-)](·-) in 1-10. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mass Spectrometric Analyses of Phosphatidylcholines in Alkali-Exposed Corneal Tissue

PubMed Central

Crane, Ashley M.; Hua, Hong-Uyen; Coggin, Andrew D.; Gugiu, Bogdan G.; Lam, Byron L.; Bhattacharya, Sanjoy K.

2012-01-01

Purpose. The aims were to determine whether exposure to sodium hydroxide results in predictable changes in phosphatidylcholine (PC) in corneal tissue and if PC profile changes correlate to exposure duration. PCs are major components of the cell membrane lipid bilayer and are often involved in biological processes such as signaling. Methods. Enucleated porcine (n = 140) and cadaver human eyes (n = 20) were exposed to water (control) and 11 M NaOH. The corneas were excised and lipids were extracted using the Bligh and Dyer method with suitable modifications. Class-specific lipid identification was carried out using a ratiometric lipid standard on a TSQ Quantum Access Max mass spectrometer. Protein amounts were determined using Bradford assays. Results. Control and alkali-treated corneas showed reproducible PC spectra for both porcine and human corneas. Over 200 PCs were identified for human and porcine control and each experimental time point. Several PC species (m/z values) consequent upon alkali exposure could not be ascribed to a recorded PC species. Control and treated groups showed 41 and 29 common species among them for porcine and human corneas, respectively. The unique PC species peaked at 12 minutes and at 30 minutes for human and porcine corneas followed by a decline consistent with an interplay of alkali penetration and hydrolyses at various time points. Conclusions. Alkali exposure dramatically changes the PC profile of cornea. Our data are consistent with penetration and hydrolysis as stochastic contributors to changes in PCs due to exposure to alkali for a finite duration and amount. PMID:22956606

Comparison of composition and absorption of sugarcane policosanols.

PubMed

Marinangeli, Christopher P F; Kassis, Amira N; Jain, Deepak; Ebine, Naoyuki; Cunnane, Stephen C; Jones, Peter J H

2007-02-01

Policosanols (PC) exist as very-long-chain alcohols derived from sugarcane currently used in many countries as a cholesterol-lowering therapy. PC purity and relative percentage composition have been suggested as primary reasons why the original Cuban PC (OPC) supplements possess lipid-lowering efficacy. The purpose of the present study was, first, to compare the relative percentage purity and PC composition of both OPC and alternative sources of PC (APC). A second objective was to feed Syrian hamsters a diet containing 0.275 mg PC/g of either the OPC or an APC product (APC1) and compare subsequent tissue, plasma and faecal PC levels. Five animals from the APC1 dietary group received a diet containing ten times the original amount of PC. Results indicate that the APC formulations have a composition that is highly consistent with the OPC supplement, with octacosanol being present within the cited 60-70 % range. PC were undetectable in the small intestine, liver, adipose or plasma in animals fed either source. Hamsters fed OPC excreted octacosanol (C28) more rapidly (P < 0.05) than hamsters receiving APC1. If the cholesterol-lowering efficacy of PC mixtures is dependent on their purity and composition, then sugarcane-derived APC products should possess similar therapeutic properties as the OPC supplement.

Procyanidins from apples (Malus pumila Mill.) extend the lifespan of Caenorhabditis elegans.

PubMed

Sunagawa, Tadahiro; Shimizu, Takahiko; Kanda, Tomomasa; Tagashira, Motoyuki; Sami, Manabu; Shirasawa, Takuji

2011-01-01

Apple polyphenols (AP) mainly consist of procyanidins (PC), which are composed of (-)-epicatechins and (+)-catechins. In order to investigate the antiageing effects of PC, we measured the lifespan of CAENORHABDITIS ELEGANS worms treated with PC. Treatment with 65 µg/mL PC extended the mean lifespan of wild-type N2 and FEM-1 worms by 12.1 % and 8.4 %, respectively, i.e., to a similar extent as resveratrol. In addition, treatment with 100 µg/mL AP also significantly prolonged the mean lifespan of the same worms by 12.0 % and 5.3 %, respectively, i.e., to a similar extent as PC. In contrast, treatment with (-)-epicatechin did not extend the lifespan of the worms. PC did not modify the growth, food intake, or fecundity of C. elegans. Treatment with PC did not extend the lifespan of MEV-1 worms, which show excessive oxidative stress, indicating that PC had no antioxidant ability in the MEV-1 mutant. Moreover, treatment with PC had no effect on the longevity of SIR-2.1 worms, which lack the activity of SIR-2, a member of the sirtuin family of NAD (+)-dependent protein deacetylases. These results indicated that PC has SIR-2.1-dependent antiageing effects on C. elegans. © Georg Thieme Verlag KG Stuttgart · New York.

High-pressure Raman study on the superconducting pyrochlore oxide Cd2Re2O7

NASA Astrophysics Data System (ADS)

Matsubayashi, Yasuhito; Hasegawa, Takumi; Ogita, Norio; Yamaura, Jun-ichi; Hiroi, Zenji

2018-05-01

The superconducting pyrochlore oxide Cd2Re2O7 (Tc = 1 K), which is now considered as a candidate of the spin-orbit-coupled metal, shows an inversion-symmetry-breaking structural transition at Ts1 = 200 K . Ts1 decreases with increasing pressure and disappears at around Pc = 4.2 GPa , where at least four high-pressure phases with tiny structural distortions are suggested by means of powder X-ray diffraction [Yamaura PRB 2017]. We have carried out Raman scattering experiments to investigate changes in the crystal symmetry under high pressures up to 4.8 GPa. A structural transition at 1.9-3.0 GPa and the recovery of inversion symmetry above Pc are observed at 12 K.

Ambipolar carrier transport properties and molecular packing structure of octahexyl-substituted copper phthalocyanine

NASA Astrophysics Data System (ADS)

Watanabe, Ken; Watanabe, Koichi; Tohnai, Norimitsu; Itani, Hiromichi; Shimizu, Yo; Fujii, Akihiko; Ozaki, Masanori

2018-04-01

The charge carrier mobility of a solution-processable low-molecular-weight organic semiconductor material, i.e., 1,4,8,11,15,18,22,25-octahexylphthalocyanine copper complex (C6PcCu), was investigated by the time-of-flight technique. The anomalous ambipolar carrier mobility was discussed from the viewpoint of the molecular packing structure, which was clarified by single-crystal X-ray structure analysis. In the comparison between the molecular packing structures of C6PcCu and its metal-free-type homologue, it was found that the difference in carrier mobility originates from the rotation of the molecule, which is caused by the steric hindrance due to the introduction of a center metal and the interpenetration of the nonperipheral alkyl chains.

Sensibilization of polymer/fullerene photovoltaic cells using Zinc Phtalocyanine studied by combinatorial technique

NASA Astrophysics Data System (ADS)

Godovsky, D.; Chen, L.; Petterson, L.; Inganäs, O.

2000-11-01

The influence of Zinc Phtalocyanine admixture to fullerene layers on top of PTOPT to the photovoltaic cells performance was studied. In order to investigate all the possible combinations of ZnPc and C60 the combinatorial technique was developed consisting in thermal co-evaporation of ZnPc and C60 from two different boats. The significant increase in solar cells photocurrent was observed, coming from ZnPc absorbance bands, especially for the layers containing 1:1 molar ratio of the components.

Switchable dual-wavelength fiber laser based on PCF Sagnac loop and broadband FBG

NASA Astrophysics Data System (ADS)

Chen, Weiguo; Lou, Shuqin; Feng, Suchun; Wang, Liwen; Li, Honglei; Guo, Tieying; Jian, Shuisheng

2009-11-01

Switchable dual-wavelength fiber laser with photonic crystal fiber (PCF) Sagnac loop and broadband fiber Bragg grating (BFBG) at room temperature is demonstrated. By adjusting the polarization controller (PC) appropriately, the laser can be switched between the stable single- and dual-wavelength lasing operations by exploiting polarization hole burning (PHB) and spectral hole burning effects (SHB).

Computer (PC/Network) Coordinator.

ERIC Educational Resources Information Center

Ohio State Univ., Columbus. Center on Education and Training for Employment.

This publication contains 22 subjects appropriate for use in a competency list for the occupation of computer (PC/network) coordinator, 1 of 12 occupations within the business/computer technologies cluster. Each unit consists of a number of competencies; a list of competency builders is provided for each competency. Titles of the 22 units are as…

Polarization splitting phenomenon of photonic crystals constructed by two-fold rotationally symmetric unit-cells

NASA Astrophysics Data System (ADS)

Yasa, U. G.; Giden, I. H.; Turduev, M.; Kurt, H.

2017-09-01

We present an intrinsic polarization splitting characteristic of low-symmetric photonic crystals (PCs) formed by unit-cells with C 2 rotational symmetry. This behavior emerges from the polarization sensitive self-collimation effect for both transverse-magnetic (TM) and transverse-electric (TE) modes depending on the rotational orientations of the unit-cell elements. Numerical analyzes are performed in both frequency and time domains for different types of square lattice two-fold rotational symmetric PC structures. At incident wavelength of λ = 1550 nm, high polarization extinction ratios with ˜26 dB (for TE polarization) and ˜22 dB (for TM polarization) are obtained with an operating bandwidth of 59 nm. Moreover, fabrication feasibilities of the designed structure are analyzed to evaluate their robustness in terms of the unit-cell orientation: for the selected PC unit-cell composition, corresponding extinction ratios for both polarizations still remain to be over 18 dB for the unit-cell rotation interval of θ = [40°-55°]. Taking all these advantages, two-fold rotationally symmetric PCs could be considered as an essential component in photonic integrated circuits for polarization control of light.

Theoretical and experimental investigations of asymmetric light transport in graded index photonic crystal waveguides

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

Giden, I. H., E-mail: igiden@etu.edu.tr; Yilmaz, D.; Turduev, M.

To provide asymmetric propagation of light, we propose a graded index photonic crystal (GRIN PC) based waveguide configuration that is formed by introducing line and point defects as well as intentional perturbations inside the structure. The designed system utilizes isotropic materials and is purely reciprocal, linear, and time-independent, since neither magneto-optical materials are used nor time-reversal symmetry is broken. The numerical results show that the proposed scheme based on the spatial-inversion symmetry breaking has different forward (with a peak value of 49.8%) and backward transmissions (4.11% at most) as well as relatively small round-trip transmission (at most 7.11%) in amore » large operational bandwidth of 52.6 nm. The signal contrast ratio of the designed configuration is above 0.80 in the telecom wavelengths of 1523.5–1576.1 nm. An experimental measurement is also conducted in the microwave regime: A strong asymmetric propagation characteristic is observed within the frequency interval of 12.8 GHz–13.3 GHz. The numerical and experimental results confirm the asymmetric transmission behavior of the proposed GRIN PC waveguide.« less

Enhanced optical power of GaN-based light-emitting diode with compound photonic crystals by multiple-exposure nanosphere-lens lithography

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

Zhang, Yonghui; Wei, Tongbo, E-mail: tbwei@semi.ac.cn; Xiong, Zhuo

2014-07-07

The light-emitting diodes (LEDs) with single, twin, triple, and quadruple photonic crystals (PCs) on p-GaN are fabricated by multiple-exposure nanosphere-lens lithography (MENLL) process utilizing the focusing behavior of polystyrene spheres. Such a technique is easy and economical for use in fabricating compound nano-patterns. The optimized tilted angle is decided to be 26.6° through mathematic calculation to try to avoid the overlay of patterns. The results of scanning electron microscopy and simulations reveal that the pattern produced by MENLL is a combination of multiple ovals. Compared to planar-LED, the light output power of LEDs with single, twin, triple, and quadruple PCsmore » is increased by 14.78%, 36.03%, 53.68%, and 44.85% under a drive current 350 mA, respectively. Furthermore, all PC-structures result in no degradation of the electrical properties. The stimulated results indicate that the highest light extraction efficiency of LED with the clover-shape triple PC is due to the largest scattering effect on propagation of light from GaN into air.« less

Achieving omnidirectional photonic band gap in sputter deposited TiO{sub 2}/SiO{sub 2} one dimensional photonic crystal

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

Jena, S., E-mail: shuvendujena9@gmail.com; Tokas, R. B.; Sarkar, P.

2015-06-24

The multilayer structure of TiO{sub 2}/SiO{sub 2} (11 layers) as one dimensional photonic crystal (1D PC) has been designed and then fabricated by using asymmetric bipolar pulse DC magnetron sputtering technique for omnidirectional photonic band gap. The experimentally measured photonic band gap (PBG) in the visible region is well matched with the theoretically calculated band structure (ω vs. k) diagram. The experimentally measured omnidirectional reflection band of 44 nm over the incident angle range of 0°-70° is found almost matching within the theoretically calculated band.

History of gonorrhea and prostate cancer in a population-based case-control study in Mexico.

PubMed

Vázquez-Salas, Ruth Argelia; Torres-Sánchez, Luisa; López-Carrillo, Lizbeth; Romero-Martínez, Martín; Manzanilla-García, Hugo A; Cruz-Ortíz, Carlos Humberto; Mendoza-Peña, Fernando; Jiménez-Ríos, Miguel Ángel; Rodríguez-Covarrubias, Francisco; Hernández-Toríz, Narciso; Moreno-Alcázar, Othón

2016-02-01

We evaluated the association between a history of sexually transmitted diseases (STDs) and the risk for prostate cancer (PC) among Mexican males. PC incident cases (n=402) that were identified at six public hospitals in Mexico City were matched by age (±5 years) with 805 population controls with no history of PC. By face-to-face interview, we obtained information about sexual history, previous STDs, sociodemographic characteristics, and familial history of PC. An unconditional logistic regression model was used to estimate the risk for PC. A total of 16.6% of men reported having had at least one previous STD, and the most frequently reported STD was gonorrhea (10.5%). After adjusting by PC familial history, the history of STD was associated with a two-fold greater risk of PC: odds ratio (OR)=2.67; 95% confidence interval (95% CI=1.91-3.73). When each STD was evaluated separately, only gonorrhea was associated with a significant increase in PC risk (OR=3.04; 95% CI=1.99-4.64). These associations were similar when we stratified by low-risk PC (Gleason <7) and high-risk PC (Gleason ≥7). These results confirm that STDs, and particularly gonorrhea, may play an etiological role in PC among Mexican males, which is consistent with a previous report from a multiethnic cohort. Copyright © 2015 Elsevier Ltd. All rights reserved.

A simple and sensitive method to measure timing accuracy.

PubMed

De Clercq, Armand; Crombez, Geert; Buysse, Ann; Roeyers, Herbert

2003-02-01

Timing accuracy in presenting experimental stimuli (visual information on a PC or on a TV) and responding (keyboard presses and mouse signals) is of importance in several experimental paradigms. In this article, a simple system for measuring timing accuracy is described. The system uses two PCs (at least Pentium II, 200 MHz), a photocell, and an amplifier. No additional boards and timing hardware are needed. The first PC, a SlavePC, monitors the keyboard presses or mouse signals from the PC under test and uses a photocell that is placed in front of the screen to detect the appearance of visual stimuli on the display. The software consists of a small program running on the SlavePC. The SlavePC is connected through a serial line with a second PC. This MasterPC controls the SlavePC through an ActiveX control, which is used in a Visual Basic program. The accuracy of our system was investigated by using a similar setup of a SlavePC and a MasterPC to generate pulses and by using a pulse generator card. These tests revealed that our system has a 0.01-msec accuracy. As an illustration, the reaction time accuracy of INQUISIT for a few applications was tested using our system. It was found that in those applications that we investigated, INQUISIT measures reaction times from keyboard presses with millisecond accuracy.

β-Octabromo- and β-Octakis(trifluoromethyl)isocorroles: New Sterically Constrained Macrocyclic Ligands

DOE PAGES

Thomas, Kolle E.; Beavers, Christine M.; Gagnon, Kevin J.; ...

2017-05-26

Here, we present a study of the acid-induced demetalation of two sterically hindered copper corroles, Cu β-octabromo-meso-triphenylcorrole (Cu[Br 8TPC]) and β-octakis(trifluoromethyl)-meso-tris(p-methoxyphenyl)corrole (Cu[(CF 3) 8TpOMePC]). Unlike reductive demetalation, which affords the free-base β-octabromocorrole, demetalation of Cu[Br 8TPC] under non- reductive conditions (CHCl 3/H 2SO 4) resulted in moderate yields of free-base 5- and 10-hydroxy isocorroles. The isomeric free bases could be complexed to Co II and Ni II, affording stable complexes. Only reductive demetalation was found to work for Cu[(CF 3) 8TpOMePC], affording a highly saddled, hydrated corrole, H 3[5-OH,10-H-(CF 3) 8TpOMePC], where the elements of water had added across C5more » and C10. Interaction of this novel free base with Co II resulted in Co[iso-10-H-[CF 3) 8TpOMePC], a Co II 10-hydro isocorrole. Finally, the new metal complexes were all characterized by single-crystal X-ray diffraction analysis and, despite their sterically hindered nature, were found to exhibit almost perfectly planar isocorrole cores.« less

Phononic band gap and wave propagation on polyvinylidene fluoride-based acoustic metamaterials

NASA Astrophysics Data System (ADS)

Oltulu, Oral; Simsek, Sevket; Mamedov, Amirullah M.; Ozbay, Ekmel

2016-12-01

In the present work, the acoustic band structure of a two-dimensional phononic crystal (PC) containing an organic ferroelectric (PVDF-polyvinylidene fluoride) and topological insulator (SnTe) was investigated by the plane-wave-expansion (PWE) method. Two-dimensional PC with square lattices composed of SnTe cylindrical rods embedded in the PVDF matrix is studied to find the allowed and stop bands for the waves of certain energy. Phononic band diagram ω = ω(k) for a 2D PC, in which non-dimensional frequencies ωa/2πc (c-velocity of wave) were plotted vs. the wavevector k along the Г-X-M-Г path in the square Brillouin zone shows five stop bands in the frequency range between 10 and 110 kHz. The ferroelectric properties of PVDF and the unusual properties of SnTe as a topological material give us the ability to control the wave propagation through the PC over a wide frequency range of 103-106 Hz. SnTe is a discrete component that allows conducting electricity on its surface but shows insulator properties through its bulk volume. Tin telluride is considered as an acoustic topological insulator as the extension of topological insulators into the field of "topological phononics".

Gene organization and alternative splicing of human prohormone convertase PC8.

PubMed Central

Goodge, K A; Thomas, R J; Martin, T J; Gillespie, M T

1998-01-01

The mammalian Ca2+-dependent serine protease prohormone convertase PC8 is expressed ubiquitously, being transcribed as 3.5, 4.3 and 6.0 kb mRNA isoforms in various tissues. To determine the origin of these various mRNA isoforms we report the characterization of the human PC8 gene, which has been previously localized to chromosome 11q23-24. Consisting of 16 exons, the human PC8 gene spans approx. 27 kb. A comparison of the position of intron-exon junctions of the human PC8 gene with the gene structures of previously reported prohormone convertase genes demonstrated a divergence of the human PC8 from the highly conserved nature of the gene organization of this enzyme family. The nucleotide sequence of the 5'-flanking region of the human PC8 is reported and possesses putative promoter elements characteristic of a GC-rich promoter. Further supporting the potential role of a GC-rich promoter element, multiple transcriptional initiation sites within a 200 bp region were demonstrated. We propose that the various mRNA isoforms of PC8 result from the inclusion of intronic sequences within transcripts. PMID:9820811

A density functional theory study of the correlation between analyte basicity, ZnPc adsorption strength, and sensor response.

PubMed

Tran, N L; Bohrer, F I; Trogler, W C; Kummel, A C

2009-05-28

Density functional theory (DFT) simulations were used to determine the binding strength of 12 electron-donating analytes to the zinc metal center of a zinc phthalocyanine molecule (ZnPc monomer). The analyte binding strengths were compared to the analytes' enthalpies of complex formation with boron trifluoride (BF(3)), which is a direct measure of their electron donating ability or Lewis basicity. With the exception of the most basic analyte investigated, the ZnPc binding energies were found to correlate linearly with analyte basicities. Based on natural population analysis calculations, analyte complexation to the Zn metal of the ZnPc monomer resulted in limited charge transfer from the analyte to the ZnPc molecule, which increased with analyte-ZnPc binding energy. The experimental analyte sensitivities from chemiresistor ZnPc sensor data were proportional to an exponential of the binding energies from DFT calculations consistent with sensitivity being proportional to analyte coverage and binding strength. The good correlation observed suggests DFT is a reliable method for the prediction of chemiresistor metallophthalocyanine binding strengths and response sensitivities.

Enhanced plastochromanol-8 accumulation during reiterated drought in maize (Zea mays L.).

PubMed

Fleta-Soriano, Eva; Munné-Bosch, Sergi

2017-03-01

Plastochromanol-8 (PC-8) belongs to the group of tocochromanols, and together with tocopherols and carotenoids, might help protect photosystem II from photoinhibition during environmental stresses. Here, we aimed to unravel the time course evolution of PC-8 together with that of vitamin E compounds, in maize (Zea mays L.) plants exposed to reiterated drought. Measurements were performed in plants grown in a greenhouse subjected to two consecutive cycles of drought-recovery. PC-8 contents, which accounted for more than 25% of tocochromanols in maize leaves, increased progressively in response to reiterated drought stress. PC-8 contents paralleled with those of vitamin E, particularly α-tocopherol. Profiling of the stress-related phytohormones (ABA, jasmonic acid and salicylic acid) was consistent with a role of ABA in the regulation of PC-8 and vitamin E biosynthesis during drought stress. Results also suggest that PC-8 may help tocopherols prevent damage to the photosynthetic apparatus. A better knowledge of the ABA-dependent regulation of PC-8 may help us manipulate the contents of this important antioxidant in crops. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Consistent Principal Component Modes from Molecular Dynamics Simulations of Proteins.

PubMed

Cossio-Pérez, Rodrigo; Palma, Juliana; Pierdominici-Sottile, Gustavo

2017-04-24

Principal component analysis is a technique widely used for studying the movements of proteins using data collected from molecular dynamics simulations. In spite of its extensive use, the technique has a serious drawback: equivalent simulations do not afford the same PC-modes. In this article, we show that concatenating equivalent trajectories and calculating the PC-modes from the concatenated one significantly enhances the reproducibility of the results. Moreover, the consistency of the modes can be systematically improved by adding more individual trajectories to the concatenated one.

Maximally asymmetric transbilayer distribution of anionic lipids alters the structure and interaction with lipids of an amyloidogenic protein dimer bound to the membrane surface

PubMed Central

Cheng, Sara Y.; Chou, George; Buie, Creighton; Vaughn, Mark W.; Compton, Campbell; Cheng, Kwan H.

2016-01-01

We used molecular dynamics simulations to explore the effects of asymmetric transbilayer distribution of anionic phosphatidylserine (PS) lipids on the structure of a protein on the membrane surface and subsequent protein–lipid interactions. Our simulation systems consisted of an amyloidogenic, beta-sheet rich dimeric protein (D42) absorbed to the phosphatidylcholine (PC) leaflet, or protein-contact PC leaflet, of two membrane systems: a single-component PC bilayer and double PC/PS bilayers. The latter comprised of a stable but asymmetric transbilayer distribution of PS in the presence of counterions, with a 1-component PC leaflet coupled to a 1-component PS leaflet in each bilayer. The maximally asymmetric PC/PS bilayer had a non-zero transmembrane potential (TMP) difference and higher lipid order packing, whereas the symmetric PC bilayer had a zero TMP difference and lower lipid order packing under physiologically relevant conditions. Analysis of the adsorbed protein structures revealed weaker protein binding, more folding in the N-terminal domain, more aggregation of the N- and C-terminal domains and larger tilt angle of D42 on the PC leaflet surface of the PC/PS bilayer versus the PC bilayer. Also, analysis of protein-induced membrane structural disruption revealed more localized bilayer thinning in the PC/PS versus PC bilayer. Although the electric field profile in the non-protein-contact PS leaflet of the PC/PS bilayer differed significantly from that in the non-protein-contact PC leaflet of the PC bilayer, no significant difference in the electric field profile in the protein-contact PC leaflet of either bilayer was evident. We speculate that lipid packing has a larger effect on the surface adsorbed protein structure than the electric field for a maximally asymmetric PC/PS bilayer. Our results support the mechanism that the higher lipid packing in a lipid leaflet promotes stronger protein–protein but weaker protein–lipid interactions for a dimeric protein on membrane surfaces. PMID:26827904

Efficient light harvesting within a C153@Zr-based MOF embedded in a polymeric film: spectral and dynamical characterization.

PubMed

Gutiérrez, M; López-González, M; Sánchez, F; Douhal, A

2017-07-21

Light harvesting is a natural phenomenon that scientists try to mimic in artificial systems. Having this in mind, attention has been focused on using new smart-materials for photonics. Herein, we report on the photobehaviour of a Zr-NDC MOF (NDC = dimethyl 2,6-naphthalenedicarboxylate) and its composite material, Coumarin153@Zr-NDC, embedded within a polymeric membrane of poly[bisphenol A carbonate-co-4,4'-(3,3,5-trimethylcyclohexylidene)diphenol carbonate] (PC). For the mixed matrix membrane (MMM) Zr-NDC/PC, we observed interparticle excimer-like formation, taking place in times shorter than 15 ps and giving rise to a red-shifted broad emission band. The interparticle interactions are supported by the SEM images, as they reflect the contact between the MOF crystals. The C153@Zr-NDC/PC material presents an energy transfer (ET) process from the excited MOF to the trapped C153 molecules in 820 ps, with a 35 nm red-shifted emission band corresponding to C153 in PC. The fluorescence quantum yield, as a result of this ET from the MOF, is high enough (25%) to explore the possibility of using this new composite material in a LED device. To elucidate the observed photobehavior, we compared it with those of C153/PC and (2,6-NDC + C153)/PC films. These results shed light on the spectroscopic and dynamical properties of these new composite materials formed by a highly fluorescent molecule, and easily synthesized MOFs and polymeric matrices, opening the way for more research based on these mixed inorganic and organic compounds for possible applications in the fields of luminescence sensing and emitting devices.

Electron transport properties in fluorinated copper-phthalocyanine films: importance of vibrational reorganization energy and molecular microstructure.

PubMed

Wu, Fu-Chiao; Cheng, Horng-Long; Yen, Chen-Hsiang; Lin, Jyu-Wun; Liu, Shyh-Jiun; Chou, Wei-Yang; Tang, Fu-Ching

2010-03-07

Electron transport (ET) properties of a series of fluorinated copper-phthalocyanine (F(16)CuPc) thin films, which were deposited at different substrate temperatures (T(sub)) ranging from 30 to 150 degrees C, have been investigated by quantum mechanical calculations of the reorganization energy (lambda(reorg)), X-ray diffraction (XRD), atomic force microscopy (AFM), and microRaman spectroscopy. Density functional theory calculations were used to predict the vibrational frequencies, normal mode displacement vectors, and electron-vibrational lambda(reorg) for the F(16)CuPc molecule. The electron mobilities (mu(e)) of F(16)CuPc thin films are strongly dependent on the T(sub), and the value of mu(e) increases with increasing T(sub) from 30 to 120 degrees C, at which point it reaches its maximum value. The importance of electron-vibrational coupling and molecular microstructures for ET properties in F(16)CuPc thin films are discussed on the basis of theoretical vibrational lambda(reorg) calculations and experimental observations of resonance Raman spectra. We observed a good correlation between mu(e) and the full-width-at-half-maximum of the vibrational bands, which greatly contributed to lambda(reorg) and/or which reflects the molecular microstructural quality of the active channel. In contrast, the crystal size analysis by XRD and surface grain morphology by AFM did not reveal a clear correlation with the ET behaviours for these different F(16)CuPc thin films. Therefore, we suggest that for organic films with weak intermolecular interactions, such as F(16)CuPc, optimized microscopic molecular-scale parameters are highly important for efficient long-range charge transport in the macroscopic devices.

PrPc Does Not Mediate Internalization of PrPSc but Is Required at an Early Stage for De Novo Prion Infection of Rov Cells▿

PubMed Central

Paquet, Sophie; Daude, Nathalie; Courageot, Marie-Pierre; Chapuis, Jérôme; Laude, Hubert; Vilette, Didier

2007-01-01

We have studied the interactions of exogenous prions with an epithelial cell line inducibly expressing PrPc protein and permissive to infection by a sheep scrapie agent. We demonstrate that abnormal PrP (PrPSc) and prion infectivity are efficiently internalized in Rov cells, whether or not PrPc is expressed. At odds with earlier studies implicating cellular heparan sulfates in PrPSc internalization, we failed to find any involvement of such molecules in Rov cells, indicating that prions can enter target cells by several routes. We further show that PrPSc taken up in the absence of PrPc was unable to promote efficient prion multiplication once PrPc expression was restored in the cells. This observation argues that interaction of PrPSc with PrPc has to occur early, in a specific subcellular compartment(s), and is consistent with the view that the first prion multiplication events may occur at the cell surface. PMID:17626095

Photoresponses in Gold Nanoparticle Single-Electron Transistors with Molecular Floating Gates

NASA Astrophysics Data System (ADS)

Noguchi, Yutaka; Yamamoto, Makoto; Ishii, Hisao; Ueda, Rieko; Terui, Toshifumi; Imazu, Keisuke; Tamada, Kaoru; Sakano, Takeshi; Matsuda, Kenji

2013-11-01

We have proposed a simple method of activating advanced functions in single-electron transistors (SETs) based on the specific properties of individual molecules. As a prototype, we fabricated a copper phthalocyanine (CuPc)-doped SET. The device consists of a gold-nanoparticle (GNP)-based SET doped with CuPc as a photoresponsive floating gate. In this paper, we report the details of the photoresponses of the CuPc-doped SET, such as conductance switching, sensitivity to the wavelength of the incident light, and multiple induced states.

trans-Bis(hexafluoroantimonato)(phthalocyaninato)copper(II).

PubMed

Gardberg, A S; Ibers, J A

2001-05-01

The title compound, trans-bis(hexafluoroantimonato-F)(phthalocyaninato-kappa(4)N(29,30,31,32))copper(II), [Cu(SbF(6))(2)(C(32)H(16)N(8))] or Cu(pc)(SbF(6))(2) (pc is phthalocyaninate), comprises a six-coordinate Cu atom, lying on an inversion center, bonded to four N atoms of a phthalocyanine ring and to F atoms of two trans SbF(6)(-) groups. The compound is presumed to consist of a Cu(II) center and a doubly oxidized phthalocyanine ring, by analogy with Cu(pc)(ReO(4))(2).

Calcium binding to Procambarus clarkii sarcoplasmic calcium binding protein splice variants.

PubMed

Rohrback, Suzanne E; Wheatly, Michele G; Gillen, Christopher M

2015-01-01

Sarcoplasmic calcium binding protein (SCP) is a high-affinity calcium buffering protein expressed in muscle of crayfish and other invertebrates. In previous work, we identified three splice variants of Procambarus clarkii SCP (pcSCP1a, pcSCP1b, and pcSCP1c) that differ in a 37 amino acid region that lies mainly between the 2nd and 3ed EF-hand calcium binding domain. To evaluate the function of the proteins encoded by the pcSCP1 transcripts, we produced recombinant pcSCP1 and used tryptophan fluorescence to characterize calcium binding. Tryptophan fluorescence of pcSCP1a decreased in response to increased calcium, while tryptophan fluorescence of the pcSCP1b and pcSCP1c variants increased. We estimated calcium binding constants and Hill coefficients with two different equations: the standard Hill equation and a modified Hill equation that accounts for contributions from two different tryptophans. The approaches gave similar results. Steady-state calcium binding constants (Kd) ranged from 2.7±0.7×10(-8)M to 5.6±0.1×10(-7)M, consistent with previous work. Variants displayed significantly different apparent calcium affinities, which were decreased in the presence of magnesium. Calcium Kd was lowest for pcSCP1a and highest for pcSCP1c. Site-directed mutagenesis of pcSCP1c residues to the amino acids of pcSCP1b decreased the calcium Kd, identifying residues outside the EF-hand domains that contribute to calcium binding in crayfish SCP. Copyright © 2014 Elsevier Inc. All rights reserved.

Colorimetric characterization models based on colorimetric characteristics evaluation for active matrix organic light emitting diode panels.

PubMed

Gong, Rui; Xu, Haisong; Tong, Qingfen

2012-10-20

The colorimetric characterization of active matrix organic light emitting diode (AMOLED) panels suffers from their poor channel independence. Based on the colorimetric characteristics evaluation of channel independence and chromaticity constancy, an accurate colorimetric characterization method, namely, the polynomial compensation model (PC model) considering channel interactions was proposed for AMOLED panels. In this model, polynomial expressions are employed to calculate the relationship between the prediction errors of XYZ tristimulus values and the digital inputs to compensate the XYZ prediction errors of the conventional piecewise linear interpolation assuming the variable chromaticity coordinates (PLVC) model. The experimental results indicated that the proposed PC model outperformed other typical characterization models for the two tested AMOLED smart-phone displays and for the professional liquid crystal display monitor as well.

Polylactic Acid-Based Polymer Blends for Durable Applications

NASA Astrophysics Data System (ADS)

Finniss, Adam

There has been considerable scientific interest in both research and commercial communities as of late in the area of biologically based or sourced plastics. As the consumption of petroleum rises and concerns about climate change increase, this field is likely to grow even larger. One bioplastic that has received a great deal of attention is polylactic acid (PLA). In the past, this material was used mainly in medical or specialty applications, but advancements in manufacturing have led to a desire to use PLA more widely, especially in durable applications. Unfortunately, PLA has several drawbacks that hinder more widespread usage of the material as a durable item: it has low ductility and impact strength in bulk applications, along with poor stability in the face of heat, humidity or liquid media. To combat these deficiencies, a number of techniques were investigated. Samples were annealed to create crystalline domains that would improve mechanical properties and reduce diffusion, blended with graphene to create barriers to diffusion throughout the material, or compounded with a polycarbonate (PC) polymer phase to protect the PLA phase and to enhance the mechanical properties of the blend. If a material containing biologically sourced components with good mechanical properties can be created, it would be desirable for durable uses such as electronics components or as an automotive grade resin. Crystallization experiments were carried out in a differential scanning calorimeter to determine the effects of heat treatment and additives on the rather slow crystallization kinetics of PLA polymer. It was determined that the blending in of the PC phase did not significantly alter the kinetics or mechanism of crystal growth. The addition of graphene to any PC/PLA formulation served as a nucleating agent which speeded up the crystallization kinetics markedly, in some cases by several orders of magnitude. Results obtained from these experiments were internally consistent, showing that no matter the treatment or formulation, PLA achieved a maximum of 30-35 percent crystallinity. Samples receiving no treatment as well as those with annealing, the addition of graphene, and in some cases annealing/graphene were subjected to both solvent and hydrolytic degradation in order to find the most stable blend or treatment. Both pellets and molded parts of varying thicknesses were investigated to evaluate the effect of diffusional resistance on long term durability. It was determined that while the addition of crystallinity or graphene platelets can provide a temporary barrier against diffusion of attacking species, PLA polymer itself is not dimensionally stable over the long lifecycle required for durable applications such as for automotive parts. In fact, PLA-only molded panels aged in distilled water at 50°C for 42 days experienced over 99% viscosity loss regardless of which treatment was applied, and nearly all mechanical strength was lost during this time. Furthermore, while the addition of graphene and the heat treatment produced diffusion barriers which could slightly enhance PLA's degradation resistance, the treatments caused the already fragile polymer to become very brittle. Solvent degradation experiments also showed that molded parts containing more than 40% PLA loading lost in excess of 75% of the original viscosity no matter what treatment was used. This showed that these materials are likely to fail well before a sufficiently long lifecycle for durable goods is achieved. Polycarbonate rich blends with less than 30% PLA as the dispersed phase showed excellent property retention after the accelerated aging tests. Formulations with up to 20% PLA content had degradation results that were nearly identical to those of 100% polycarbonate, which literature has shown to have useful lifecycles for durable applications of up to 20 years. By completely encapsulating the PLA in the polycarbonate matrix, which occurred at about 30% PLA by maximum, it was fully protected by the more stable phase. Lastly, molded parts of differing thicknesses were hydrolytically degraded to examine the effects of diffusion resistance on the mechanical properties of untreated PC/PLA blends. It was determined that, similar to the droplet morphology study, the effect of PC content was the most dominating factor in the durability of the formulations. In fact, if molded parts reach a critical thickness, a transition from ductile to brittle failure modes can be observed. The rate of diffusion through the materials was also determined to be much faster than the rate of PLA hydrolysis. It is concluded that the most effective way to create a durable material containing a significant bio-based content is to completely encapsulate PLA polymer with the more stable polycarbonate phase. Materials containing up to about 30% PLA at maximum were shown to be sufficiently durable so that they may be employed in similar automotive and electrical applications as for pure polycarbonate. (Abstract shortened by UMI.)

Frenkel-Charge-Transfer exciton intermixing theory for molecular crystals with two isolated Frenkel exciton states.

NASA Astrophysics Data System (ADS)

Bondarev, Igor; Popescu, Adrian

We develop an analytical theory for the intra-intermolecular exciton intermixing in periodic 1D chains of planar organic molecules with two isolated low-lying Frenkel exciton states, typical of copper phthalocyanine (CuPc) and other transition metal phthalocyanine molecules. We formulate the Hamiltonian and use the exact Bogoliubov diagonalization procedure to derive the eigen energy spectrum for the two lowest intramolecular Frenkel excitons coupled to the intermolecular charge transfer (CT) exciton state. By comparing our theoretical spectrum with available experimental CuPc absorption data, we obtain the parameters of the Frenkel-CT exciton intermixing in CuPc thin films. The two Frenkel exciton states here are spaced apart by 0.26 eV, and the charge transfer exciton state is 50 meV above the lowest Frenkel exciton. Both Frenkel excitons are strongly mixed with the CT exciton, showing the coupling constant 0.17 eV in agreement with earlier electron transport experiments. Our results can be used for the proper interpretation of the physical properties of crystalline phthalocyanines. DOE-DE-SC0007117 (I.B.), UNC-GA ROI Grant (A.P.).

Spin-orbit coupling and transport in strongly correlated two-dimensional systems

NASA Astrophysics Data System (ADS)

Huang, Jian; Pfeiffer, L. N.; West, K. W.

2017-05-01

Measuring the magnetoresistance (MR) of ultraclean GaAs two-dimensional holes for a large rs range of 20-50, two striking behaviors in relation to the spin-orbit coupling (SOC) emerge in response to strong electron-electron interaction. First, in exact correspondence to the zero-field metal-to-insulator transition (MIT), the sign of the MR switches from being positive in the metallic regime to being negative in the insulating regime when the carrier density crosses the critical density pc of MIT (rs˜39 ). Second, as the SOC-driven correction Δ ρ to the MR decreases with reducing carrier density (or the in-plane wave vector), it exhibits an upturn in the close proximity just above pc where rs is beyond 30, indicating a substantially enhanced SOC effect. This peculiar behavior echoes with a trend of delocalization long suspected for the SOC-interaction interplay. Meanwhile, for p 40 , in contrast to the common belief that a magnet field enhances Wigner crystallization, the negative MR is likely linked to enhanced interaction.

Distinctive effect on nerve growth factor-induced PC12 cell neurite outgrowth by two unique neolignan enantiomers from Illicium merrillianum

PubMed Central

Tian, Xinhui; Yue, Rongcai; Zeng, Huawu; Li, Honglin; Shan, Lei; He, Weiwei; Shen, Yunheng; Zhang, Weidong

2015-01-01

Merrillianoid (1), a racemic neolignan possessing the characteristic benzo-2,7-dioxabicyclo[3.2.1]octane moiety, was isolated from the branches and leaves of Illicium merrillianum. Chiral separation of 1 gave two enantiomers (+)−1 and (−)−1. The structure of 1 was established by comprehensive spectroscopic analysis and single crystal X-ray diffraction. The absolute configurations of enantiomers were determined by quantum mechanical calculation. Compound (+)−1 exhibited a better neurotrophic activity than racemate 1 by promoting nerve growth factor (NGF) induced PC12 cell neurite outgrowth, while (−)−1 showed a distinctive inhibitory effect. Furthermore, a mechanism study indicated that the two enantiomers influenced NGF-induced neurite outgrowth of PC12 cells possibly by interacting with the trkA receptor, and extracellular signal regulated kinases 1/2 (ERK1/2) and mitogen-activated protein kinase (MEK) in Ras/ERK signal cascade. But the phosphorylation level of serine/threonine kinase Akt1 and Akt2 in PI3K/Akt signal pathway showed no significant difference between (+)−1 and (−)−1. PMID:26585042

Effects of Solvent Composition on Liquid Range, Glass Transition, and Conductivity of Electrolytes of a (Li, Cs)PF 6 Salt in EC-PC-EMC Solvents

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

Ding, Michael S.; Li, Qiuyan; Li, Xing

Electrolytes of 1 M LiPF 6 (lithium hexafluorophosphate) and 0.05 M CsPF 6 (cesium hexafluorophosphate) in EC-PC-EMC (ethylene carbonate-propylene carbonate-ethyl methyl carbonate) solvents of varying solvent compositions were studied for the effects of solvent composition on the lower limit of liquid range, viscosity (as reflected by the glass transition temperature), and electrolytic conductivity. In addition, a ternary phase diagram of EC-PC-EMC was constructed and crystallization temperatures of EC and EMC were calculated to assist the interpretation and understanding of the change of liquid range with solvent composition. A function based on Vogel-Fulcher-Tammann equation was fitted to the conductivity data inmore » their entirety and plotted as conductivity surfaces in solvent composition space for more direct and clear comparisons and discussions. Changes of viscosity and dielectric constant of the solvents with their composition, in relation to those of the solvent components, were found to be underlying many of the processes studied.« less

Magnetic and Magnetocaloric Properties of Ca0.97La0.03MnO3 Manganites

NASA Astrophysics Data System (ADS)

Gong, G. D.; Hu, P. F.; Li, Y.; Kim, D. H.; Liu, C. L.; Phan, T. L.; Ho, T. A.; Yu, S. C.; Telegin, A.; Naumov, S. V.

2016-07-01

In spite of many previous studies on electron-doped CaMnO3 perovskite manganites, detailed investigations into the influence of low-doping concentrations on their magnetic and magnetocaloric (MC) properties have not been carried out yet. Additionally, there is still the lack of the comparison between single-crystal (SC) and polycrystalline (PC) materials. Dealing with these problems, we prepared orthorhombic Ca0.97La0.03MnO3 SC and PC samples. Magnetization measurements versus the temperature and magnetic field revealed remarkable differences in the magnetic property, particularly around the antiferromagnetic/ferromagnetic-paramagnetic phase-transition region. The analyses of the magnetization versus magnetic field, M( H), data indicated a weak MC effect with magnetic-entropy changes less than 0.1 J kg-1 K-1 for an applied field interval H = 10 kOe because ferromagnetic interactions between Mn3+ and Mn4+ ions are insignificant. The differences in the magnetic and MC properties of the SC and PC samples are ascribed to the effects of grain boundary, magnetic anisotropy, and nonstoichiometry in oxygen.

A visual water vapor photonic crystal sensor with PVA/SiO2 opal structure

NASA Astrophysics Data System (ADS)

Yang, Haowei; Pan, Lei; Han, Yingping; Ma, Lihua; Li, Yao; Xu, Hongbo; Zhao, Jiupeng

2017-11-01

In study, we proposed a simple yet fast optical sensing motif based on thimbleful of polyvinyl alcohol (PVA) infiltrated photonic crystal (PC), which allows for high efficiency in vapor sensing through changes in their inter-layer space. Linear response to a broad dynamic range of vapor concentration was realized. Ultrafast response time (<1 s) and excellent recyclability were also demonstrated. Selective response to a vapor was exhibited, reflecting well the characteristic sorption properties of PVA, with which colorimetric reporting was readily achieved. These substantial improvements in performance are attributed to the efficacy of signal transduction and the enhanced signal transduction because of thimbleful PVA infiltrated space between adjacent SiO2 nanospheres.

Switchable multi-wavelength fiber ring laser based on a compact in-fiber Mach-Zehnder interferometer with photonic crystal fiber

NASA Astrophysics Data System (ADS)

Chen, W. G.; Lou, S. Q.; Feng, S. C.; Wang, L. W.; Li, H. L.; Guo, T. Y.; Jian, S. S.

2009-11-01

Switchable multi-wavelength fiber ring laser with an in-fiber Mach-Zehnder interferometer incorporated into the ring cavity serving as wavelength-selective filter at room temperature is demonstrated. The filter is formed by splicing a section of few-mode photonic crystal fiber (PCF) and two segments of single mode fiber (SMF) with the air-holes on the both sides of PCF intentionally collapsed in the vicinity of the splices. By adjusting the states of the polarization controller (PC) appropriately, the laser can be switched among the stable single-, dual- and triple-wavelength lasing operations by exploiting polarization hole burning (PHB) effect.

Switchable dual-wavelength erbium-doped fiber laser based on the photonic crystal fiber loop mirror and chirped fiber Bragg grating

NASA Astrophysics Data System (ADS)

Chen, Wei-Guo; Lou, Shu-Qin; Wang, Li-Wen; Li, Hong-Lei; Guo, Tieying; Jian, Shui-Sheng

2010-03-01

The switchable dual-wavelength erbium-doped fiber laser (EDFL) with a two-mode photonic crystal fiber (PCF) loop mirror and a chirped fiber Bragg grating (CFBG) at room temperature is proposed and experimentally demonstrated. The two-mode PCF loop mirror is formed by inserting a piece of two-mode PCF into a Sagnac loop mirror, with the air-holes of the PCF intentionally collapsing at the splices. By adjusting the state of the polarization controller (PC) appropriately, the laser can be switched between the stable single- and dual-wavelength operations by means of the polarization hole burning (PHB) and spectral hole burning (SHB) effects.

Fabrication of a Quartz-Crystal-Microbalance/Optical-Waveguide Hybrid Sensor and In situ Evaluation of Vacuum-Evaporated Lead Phthalocyanine Thin Film

NASA Astrophysics Data System (ADS)

Shinbo, Kazunari; Uno, Akihiro; Hirakawa, Ryo; Baba, Akira; Ohdaira, Yasuo; Kato, Keizo; Kaneko, Futao

2013-05-01

In this study, we fabricated a novel quartz-crystal-microbalance (QCM)/optical-waveguide hybrid sensor. An in situ observation of a lead phthalocyanine (PbPc) thin-film deposition was conducted during vacuum evaporation, and the effectiveness of the sensor was demonstrated. The film thickness was obtained from the QCM frequency, and the optical absorption of the film was observed by optical waveguide spectroscopy using part of the QCM substrate without the electrode. The film absorption depends on the polarization direction, substrate temperature and deposition rate, owing to aggregate formation. The thickness dependence of the absorption property was also investigated.

Evaluation of the internal construct validity of the Personal Care Participation Assessment and Resource Tool (PC-PART) using Rasch analysis.

PubMed

Darzins, Susan; Imms, Christine; Di Stefano, Marilyn; Taylor, Nicholas F; Pallant, Julie F

2014-11-05

The Personal Care Participation Assessment and Resource Tool (PC-PART) is a 43-item, clinician-administered assessment, designed to identify patients' unmet needs (participation restrictions) in activities of daily living (ADL) required for community life. This information is important for identifying problems that need addressing to enable, for example, discharge from inpatient settings to community living. The objective of this study was to evaluate internal construct validity of the PC-PART using Rasch methods. Fit to the Rasch model was evaluated for 41 PC-PART items, assessing threshold ordering, overall model fit, individual item fit, person fit, internal consistency, Differential Item Functioning (DIF), targeting of items and dimensionality. Data used in this research were taken from admission data from a randomised controlled trial conducted at two publically funded inpatient rehabilitation units in Melbourne, Australia, with 996 participants (63% women; mean age 74 years) and with various impairment types. PC-PART items assessed as one scale, and original PC-PART domains evaluated as separate scales, demonstrated poor fit to the Rasch model. Adequate fit to the Rasch model was achieved in two newly formed PC-PART scales: Self-Care (16 items) and Domestic Life (14 items). Both scales were unidimensional, had acceptable internal consistency (PSI =0.85, 0.76, respectively) and well-targeted items. Rasch analysis did not support conventional summation of all PC-PART item scores to create a total score. However, internal construct validity of the newly formed PC-PART scales, Self-Care and Domestic Life, was supported. Their Rasch-derived scores provided interval-level measurement enabling summation of scores to form a total score on each scale. These scales may assist clinicians, managers and researchers in rehabilitation settings to assess and measure changes in ADL participation restrictions relevant to community living. Data used in this research were gathered during a registered randomised controlled trial: Australian and New Zealand Clinical Trials Registry ACTRN12609000973213. Ethics committee approval was gained for secondary analysis of data for this study.

Improvement Noise Insulation Performance of Polycarbonate Pane using Sandwich Structure

NASA Astrophysics Data System (ADS)

Shen, Min; Nagamura, Kazuteru; Nakagawa, Noritoshi; Okamura, Masaharu

Polycarbonate (PC) laminates offer the possibility of designing strong and light weight panes application in automobile. However, the noise insulation performance of PC pane is worse than glass pane because of its high rate of stiffness to low weight. In this work, a new ultra-thin(less than 10mm) sandwich pane is proposed to obtain high transmission loss(TL). The sandwich structure consists of two thin laminates plates of the same PC material and a thin lightweight damping core bonded between those plates. Then TL is predicted using decoupled equations representing symmetric and anti-symmetric motions for a sandwich PC pane. The effects of various structural and material parameters on noise insulation performance are investigated with numerical examples. Numerical results show that the shear rigidity has evident effect on coincidence frequency and proposed structure has better noise insulation properties than single layer PC pane of equivalent thickness.

Mode control in photonic crystal surface emitting lasers (PCSELs) through in-plane feedback (Conference Presentation)

NASA Astrophysics Data System (ADS)

Taylor, Richard J. E.; Li, Guangrui; Ivanov, Pavlo; Childs, David T. D.; Stevens, Ben J.; Babazadeh, Nasser; Ignatova, Olesya; Hogg, Richard A.

2017-02-01

All-semiconductor photonic crystal surface-emitting lasers (PCSELs) operating in CW mode at room temperature and coherently coupled arrays of these lasers are reviewed. These PCSELs are grown via MOVPE on GaAs substrates and include QW active elements and GaAs/InGaP photonic crystal (PC) layer situated above this active zone. Atoms of triangular shapes have been shown to increase optical power from the PCSEL but are also shown to result in a competition between lasing modes. Simulation shows that the energy splitting of lasing modes is smaller for triangular atoms, than for circles making high power single-mode devices difficult to achieve. In this work we experimentally investigate the effect of lateral optical feedback introduced by a facet cleave along one or two perpendicular PCSEL edges. This cleavage plane is misaligned to the PC resulting in a periodic variation of facet phase along the side of the device. Results confirm that a single cleave selects the lowest threshold 2D lasing mode, resulting in a 20% reduction in threshold current and favours single-mode emission. The addition of a second cleave at right-angles to the first has no significant effect upon threshold current. The virgin device is shown to have a symmetric far-field (1 degree) whilst a single cleave produces a 1 degree divergence perpendicular to cleave and 5 degree parallel to cleave. The second orthogonal cleave results in the far field becoming symmetric again but with a divergence angle of 1 degree indicating that single-mode lasing is supported over a wider area.

Restoring sensitivity to oxaliplatin by a novel approach in gemcitabine-resistant pancreatic cancer cells in vitro and in vivo

PubMed Central

Banerjee, Sanjeev; Kong, Dejuan; Azmi, Asfar S.; Wang, Zhiwei; Ahmad, Aamir; Sethi, Seema; Sarkar, Fazlul H.

2011-01-01

Oxaliplatin (OxP) has been used in combination therapy with gemcitabine for the treatment of pancreatic cancer (PC), but the beneficial effect was marginal, which is believed to be due to de novo and acquired drug resistance of PC. Here, we report our in vitro and in vivo preclinical evidence in support of chemosensitization of drug-resistant cells by a nontoxic chemopreventive agent (genistein). Genistein pretreatment together with low concentration of OxP showed significant reduction in cell viability and colony formation concomitant with increased apoptosis (p < 0.01), which was highly synergistic. Drug resistance of PC is allegedly linked with both constitutive and OxP-induced activation of NF-κB, and we found that inactivation of (nuclear factor kappa B) NF-κB by genistein before treatment of cells with OxP was required for cell killing, which was consistent with the downregulation of NF-κB and its downstream antiapoptotic genes (Bcl-2, XIAPs and survivin). Most importantly, our in vivo experiments using orthotopic mouse model showed significant reduction in tumor size (p < 0.01) and reduction of locoregional lymph node metastasis by combination treatment. These results were also consistent with inactivation of NF-κB and the downregulation of NF-κB downstream genes, decreased proliferation marker (Ki-67) and increased apoptosis (TUNEL) in tumor remnants, all of which was consistent with in vitro findings. From these results, we conclude that genistein sensitizes drug-resistant PC to OxP, which is mechanistically linked with inactivation of NF-κB signaling, resulting in greater antitumor effects, and thus our data suggest that this approach could be useful in improving the treatment outcome for patients diagnosed with PC. PMID:20824697

Energy-Constrained Recharge, Assimilation, and Fractional Crystallization (EC-RAχFC): A Visual Basic computer code for calculating trace element and isotope variations of open-system magmatic systems

NASA Astrophysics Data System (ADS)

Bohrson, Wendy A.; Spera, Frank J.

2007-11-01

Volcanic and plutonic rocks provide abundant evidence for complex processes that occur in magma storage and transport systems. The fingerprint of these processes, which include fractional crystallization, assimilation, and magma recharge, is captured in petrologic and geochemical characteristics of suites of cogenetic rocks. Quantitatively evaluating the relative contributions of each process requires integration of mass, species, and energy constraints, applied in a self-consistent way. The energy-constrained model Energy-Constrained Recharge, Assimilation, and Fractional Crystallization (EC-RaχFC) tracks the trace element and isotopic evolution of a magmatic system (melt + solids) undergoing simultaneous fractional crystallization, recharge, and assimilation. Mass, thermal, and compositional (trace element and isotope) output is provided for melt in the magma body, cumulates, enclaves, and anatectic (i.e., country rock) melt. Theory of the EC computational method has been presented by Spera and Bohrson (2001, 2002, 2004), and applications to natural systems have been elucidated by Bohrson and Spera (2001, 2003) and Fowler et al. (2004). The purpose of this contribution is to make the final version of the EC-RAχFC computer code available and to provide instructions for code implementation, description of input and output parameters, and estimates of typical values for some input parameters. A brief discussion highlights measures by which the user may evaluate the quality of the output and also provides some guidelines for implementing nonlinear productivity functions. The EC-RAχFC computer code is written in Visual Basic, the programming language of Excel. The code therefore launches in Excel and is compatible with both PC and MAC platforms. The code is available on the authors' Web sites http://magma.geol.ucsb.edu/and http://www.geology.cwu.edu/ecrafc) as well as in the auxiliary material.

Poikilodermatous changes on the forearms of a woman practicing aroma-therapy: extracervical poikiloderma of Civatte?*

PubMed Central

Katoulis, Alexandros; Makris, Michalis; Gregoriou, Stamatis; Rallis, Eustathios; Kanelleas, Antonis; Stavrianeas, Nicolaos; Rigopoulos, Dimitris

2014-01-01

We report the case of a 48-year-old, Caucasian female who presented with slowly progressing asymptomatic poikilodermatous changes of the extensor aspects of the forearms. She also had typical Poikiloderma of Civatte on the V of the neck and erythemato-telangiectatic rosacea of the central face. The patient had been practicing aroma-therapy for many years. Histologic examination revealed findings consistent with PC. Patch-testing revealed positive reactions to Fragrance mix and Nickel sulphate. Based on clinical and histological findings, a diagnosis of extracervical PC was suggested. PC with extra-cervical or extra-facial involvement is rare. In addition, this case supports the theory that contact sensitization to fragrances may contribute to the development of PC. PMID:25054757

Description of the three axis low-g accelerometer package

NASA Technical Reports Server (NTRS)

Amalavage, A. J.; Fikes, E. H.; Berry, E. H.

1978-01-01

The three axis low-g accelerometer package designed for use on the Space Processing Application Rocket (SPAR) Program is described. The package consists of the following major sections: (1) three Kearfott model 2412 accelerometers mounted in an orthogonal triad configuration on a temperature controlled, thermally isolated cube, (2) the accelerometer servoelectronics (printed circuit cards PC-6 through PC-12), and (3) the signal conditioner (printed circuit cards PC-15 and PC-16). The measurement range is 0 + or - 0.031 g with a quantization of 1.1 x 10 to the 7th power g. The package was flown successfully on six SPAR launches with the Black Brant booster. These flights provide approximately 300 s of free fall or zero-g environment.

Preparation, crystal structure, vibrational spectral and density functional studies of bis (4-nitrophenol)-2,4,6-triamino-1,3,5-triazine monohydrate

NASA Astrophysics Data System (ADS)

Kanagathara, N.; Marchewka, M. K.; Drozd, M.; Renganathan, N. G.; Gunasekaran, S.; Anbalagan, G.

2013-10-01

An organic-organic salt, bis (4-nitrophenol) 2,4,6-triamino 1,3,5-triazine monohydrate (BNPM) has been prepared by slow evaporation technique at room temperature. Single crystal X-ray diffraction analysis reveals that the compound crystallizes in triclinic system with centrosymmetric space group P-1. IR and Raman spectra of BNPM have been recorded and analyzed. The study has been extended to confocal Raman spectral analysis. Band assignments have been made for the melamine and p-nitrophenol molecules. Vibrational spectra have also been discussed on the basis of quantum chemical density functional theory calculations using Firefly (PC GAMESS) Version 7.1 G. Vibrational frequencies are calculated and scaled values are compared with the experimental one. The Mulliken charges, HOMO-LUMO orbital energies are calculated and analyzed. The chemical structure of the compound was established by 1H NMR and 13C NMR spectra.

Comparison of phase-contrast MR and flow simulations for the study of CSF dynamics in the cervical spine.

PubMed

Lindstrøm, Erika Kristina; Schreiner, Jakob; Ringstad, Geir Andre; Haughton, Victor; Eide, Per Kristian; Mardal, Kent-Andre

2018-06-01

Background Investigators use phase-contrast magnetic resonance (PC-MR) and computational fluid dynamics (CFD) to assess cerebrospinal fluid dynamics. We compared qualitative and quantitative results from the two methods. Methods Four volunteers were imaged with a heavily T2-weighted volume gradient echo scan of the brain and cervical spine at 3T and with PC-MR. Velocities were calculated from PC-MR for each phase in the cardiac cycle. Mean pressure gradients in the PC-MR acquisition through the cardiac cycle were calculated with the Navier-Stokes equations. Volumetric MR images of the brain and upper spine were segmented and converted to meshes. Models of the subarachnoid space were created from volume images with the Vascular Modeling Toolkit. CFD simulations were performed with a previously verified flow solver. The flow patterns, velocities and pressures were compared in PC-MR and CFD flow images. Results PC-MR images consistently revealed more inhomogeneous flow patterns than CFD, especially in the anterolateral subarachnoid space where spinal nerve roots are located. On average, peak systolic and diastolic velocities in PC-MR exceeded those in CFD by 31% and 41%, respectively. On average, systolic and diastolic pressure gradients calculated from PC-MR exceeded those of CFD by 11% and 39%, respectively. Conclusions PC-MR shows local flow disturbances that are not evident in typical CFD. The velocities and pressure gradients calculated from PC-MR are systematically larger than those calculated from CFD.

Waveform-preserved unidirectional acoustic transmission based on impedance-matched acoustic metasurface and phononic crystal

NASA Astrophysics Data System (ADS)

Song, Ai-Ling; Chen, Tian-Ning; Wang, Xiao-Peng; Wan, Le-Le

2016-08-01

The waveform distortion happens in most of the unidirectional acoustic transmission (UAT) devices proposed before. In this paper, a novel type of waveform-preserved UAT device composed of an impedance-matched acoustic metasurface (AMS) and a phononic crystal (PC) structure is proposed and numerically investigated. The acoustic pressure field distributions and transmittance are calculated by using the finite element method. The subwavelength AMS that can modulate the wavefront of the transmitted wave at will is designed and the band structure of the PC structure is calculated and analyzed. The sound pressure field distributions demonstrate that the unidirectional acoustic transmission can be realized by the proposed UAT device without changing the waveforms of the output waves, which is the distinctive feature compared with the previous UAT devices. The physical mechanism of the unidirectional acoustic transmission is discussed by analyzing the refraction angle changes and partial band gap map. The calculated transmission spectra show that the UAT device is valid within a relatively broad frequency range. The simulation results agree well with the theoretical predictions. The proposed UAT device provides a good reference for designing waveform-preserved UAT devices and has potential applications in many fields, such as medical ultrasound, acoustic rectifiers, and noise insulation.

Identifying aggressive prostate cancer foci using a DNA methylation classifier.

PubMed

Mundbjerg, Kamilla; Chopra, Sameer; Alemozaffar, Mehrdad; Duymich, Christopher; Lakshminarasimhan, Ranjani; Nichols, Peter W; Aron, Manju; Siegmund, Kimberly D; Ukimura, Osamu; Aron, Monish; Stern, Mariana; Gill, Parkash; Carpten, John D; Ørntoft, Torben F; Sørensen, Karina D; Weisenberger, Daniel J; Jones, Peter A; Duddalwar, Vinay; Gill, Inderbir; Liang, Gangning

2017-01-12

Slow-growing prostate cancer (PC) can be aggressive in a subset of cases. Therefore, prognostic tools to guide clinical decision-making and avoid overtreatment of indolent PC and undertreatment of aggressive disease are urgently needed. PC has a propensity to be multifocal with several different cancerous foci per gland. Here, we have taken advantage of the multifocal propensity of PC and categorized aggressiveness of individual PC foci based on DNA methylation patterns in primary PC foci and matched lymph node metastases. In a set of 14 patients, we demonstrate that over half of the cases have multiple epigenetically distinct subclones and determine the primary subclone from which the metastatic lesion(s) originated. Furthermore, we develop an aggressiveness classifier consisting of 25 DNA methylation probes to determine aggressive and non-aggressive subclones. Upon validation of the classifier in an independent cohort, the predicted aggressive tumors are significantly associated with the presence of lymph node metastases and invasive tumor stages. Overall, this study provides molecular-based support for determining PC aggressiveness with the potential to impact clinical decision-making, such as targeted biopsy approaches for early diagnosis and active surveillance, in addition to focal therapy.

Insights into the carboxyltransferase reaction of pyruvate carboxylase from the structures of bound product and intermediate analogues

PubMed Central

Lietzan, Adam D.; St. Maurice, Martin

2014-01-01

Pyruvate carboxylase (PC) is a biotin-dependent enzyme that catalyzes the MgATP- and bicarbonate-dependent carboxylation of pyruvate to oxaloacetate, an important anaplerotic reaction in central metabolism. The carboxyltransferase (CT) domain of PC catalyzes the transfer of a carboxyl group from carboxybiotin to the accepting substrate, pyruvate. It has been hypothesized that the reactive enolpyruvate intermediate is stabilized through a bidentate interaction with the metal ion in the CT domain active site. Whereas bidentate ligands are commonly observed in enzymes catalyzing reactions proceeding through an enolpyruvate intermediate, no bidentate interaction has yet been observed in the CT domain of PC. Here, we report three X-ray crystal structures of the Rhizobium etli PC CT domain with the bound inhibitors oxalate, 3-hydroxypyruvate, and 3-bromopyruvate. Oxalate, a stereoelectronic mimic of the enolpyruvate intermediate, does not interact directly with the metal ion. Instead, oxalate is buried in a pocket formed by several positively charged amino acid residues and the metal ion. Furthermore, both 3-hydroxypyruvate and 3-bromopyruvate, analogs of the reaction product oxaloacetate, bind in an identical manner to oxalate suggesting that the substrate maintains its orientation in the active site throughout catalysis. Together, these structures indicate that the substrates, products and intermediates in the PC-catalyzed reaction are not oriented in the active site as previously assumed. The absence of a bidentate interaction with the active site metal appears to be a unique mechanistic feature among the small group of biotin-dependent enzymes that act on α-keto acid substrates. PMID:24157795

Maximally asymmetric transbilayer distribution of anionic lipids alters the structure and interaction with lipids of an amyloidogenic protein dimer bound to the membrane surface.

PubMed

Cheng, Sara Y; Chou, George; Buie, Creighton; Vaughn, Mark W; Compton, Campbell; Cheng, Kwan H

2016-03-01

We used molecular dynamics simulations to explore the effects of asymmetric transbilayer distribution of anionic phosphatidylserine (PS) lipids on the structure of a protein on the membrane surface and subsequent protein-lipid interactions. Our simulation systems consisted of an amyloidogenic, beta-sheet rich dimeric protein (D42) absorbed to the phosphatidylcholine (PC) leaflet, or protein-contact PC leaflet, of two membrane systems: a single-component PC bilayer and double PC/PS bilayers. The latter comprised of a stable but asymmetric transbilayer distribution of PS in the presence of counterions, with a 1-component PC leaflet coupled to a 1-component PS leaflet in each bilayer. The maximally asymmetric PC/PS bilayer had a non-zero transmembrane potential (TMP) difference and higher lipid order packing, whereas the symmetric PC bilayer had a zero TMP difference and lower lipid order packing under physiologically relevant conditions. Analysis of the adsorbed protein structures revealed weaker protein binding, more folding in the N-terminal domain, more aggregation of the N- and C-terminal domains and larger tilt angle of D42 on the PC leaflet surface of the PC/PS bilayer versus the PC bilayer. Also, analysis of protein-induced membrane structural disruption revealed more localized bilayer thinning in the PC/PS versus PC bilayer. Although the electric field profile in the non-protein-contact PS leaflet of the PC/PS bilayer differed significantly from that in the non-protein-contact PC leaflet of the PC bilayer, no significant difference in the electric field profile in the protein-contact PC leaflet of either bilayer was evident. We speculate that lipid packing has a larger effect on the surface adsorbed protein structure than the electric field for a maximally asymmetric PC/PS bilayer. Our results support the mechanism that the higher lipid packing in a lipid leaflet promotes stronger protein-protein but weaker protein-lipid interactions for a dimeric protein on membrane surfaces. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Implementation of data acquisition interface using on-board field-programmable gate array (FPGA) universal serial bus (USB) link

NASA Astrophysics Data System (ADS)

Yussup, N.; Ibrahim, M. M.; Lombigit, L.; Rahman, N. A. A.; Zin, M. R. M.

2014-02-01

Typically a system consists of hardware as the controller and software which is installed in the personal computer (PC). In the effective nuclear detection, the hardware involves the detection setup and the electronics used, with the software consisting of analysis tools and graphical display on PC. A data acquisition interface is necessary to enable the communication between the controller hardware and PC. Nowadays, Universal Serial Bus (USB) has become a standard connection method for computer peripherals and has replaced many varieties of serial and parallel ports. However the implementation of USB is complex. This paper describes the implementation of data acquisition interface between a field-programmable gate array (FPGA) board and a PC by exploiting the USB link of the FPGA board. The USB link is based on an FTDI chip which allows direct access of input and output to the Joint Test Action Group (JTAG) signals from a USB host and a complex programmable logic device (CPLD) with a 24 MHz clock input to the USB link. The implementation and results of using the USB link of FPGA board as the data interfacing are discussed.

Implementation of data acquisition interface using on-board field-programmable gate array (FPGA) universal serial bus (USB) link

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

Yussup, N.; Ibrahim, M. M.; Lombigit, L.

Typically a system consists of hardware as the controller and software which is installed in the personal computer (PC). In the effective nuclear detection, the hardware involves the detection setup and the electronics used, with the software consisting of analysis tools and graphical display on PC. A data acquisition interface is necessary to enable the communication between the controller hardware and PC. Nowadays, Universal Serial Bus (USB) has become a standard connection method for computer peripherals and has replaced many varieties of serial and parallel ports. However the implementation of USB is complex. This paper describes the implementation of datamore » acquisition interface between a field-programmable gate array (FPGA) board and a PC by exploiting the USB link of the FPGA board. The USB link is based on an FTDI chip which allows direct access of input and output to the Joint Test Action Group (JTAG) signals from a USB host and a complex programmable logic device (CPLD) with a 24 MHz clock input to the USB link. The implementation and results of using the USB link of FPGA board as the data interfacing are discussed.« less

Phthalocyanine based metal containing porous carbon sheet

NASA Astrophysics Data System (ADS)

Honda, Z.; Sakaguchi, Y.; Tashiro, M.; Hagiwara, M.; Kida, T.; Sakai, M.; Fukuda, T.; Kamata, N.

2017-03-01

Highly-ordered fused-ring poly copper phthalocyanine (PCuPc) was prepared using copper octacyanophthalocyanine as a building block, and two-dimensional (2D) square superlattices were directly observed by the transmission electron microscopy. Remarkably, we have found a formation of polymer network that consists of a 2D porous PCuPc sheet in which the centers of phthalocyanine units are alternately occupied by Cu atom and vacancy. Using this "half-filling" PCuPc, it must be possible to create alternating arrangements for transition metal centers, and therefore control the magnetic properties of the 2D carbon sheets.

Nanoscale Morphology of PTB7 Based Organic Photovoltaics as a Function of Fullerene Size

DOE PAGES

Roehling, John D.; Baran, Derya; Sit, Joseph; ...

2016-08-08

High efficiency polymer:fullerene photovoltaic device layers self-assemble with hierarchical features from ångströms to 100’s of nanometers. The feature size, shape, composition, orientation, and order all contribute to device efficiency and are simultaneously difficult to study due to poor contrast between carbon based materials. This study seeks to increase device efficiency and simplify morphology measurements by replacing the typical fullerene acceptor with endohedral fullerene Lu 3N@PC 80BEH. The metal atoms give excellent scattering contrast for electron beam and x-ray experiments. Additionally, Lu 3N@PC 80BEH has a lower electron affinity than standard fullerenes, which can raise the open circuit voltage of photovoltaicmore » devices. Electron microscopy techniques are used to produce a detailed account of morphology evolution in mixtures of Lu 3N@PC 80BEH with the record breaking donor polymer, PTB7 and coated using solvent mixtures. We demonstrate that common solvent additives like 1,8-diiodooctane or chloronapthalene do not improve the morphology of endohedral fullerene devices as expected. The poor device performance is attributed to the lack of mutual miscibility between this particular polymer:fullerene combination and to co-crystallization of Lu 3N@PC 80BEH with 1,8-diiodooctane. This negative result explains why solvent additives mixtures are not necessarily a morphology cure-all.« less

Nanoscale Morphology of PTB7 Based Organic Photovoltaics as a Function of Fullerene Size

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

Roehling, John D.; Baran, Derya; Sit, Joseph

High efficiency polymer:fullerene photovoltaic device layers self-assemble with hierarchical features from ångströms to 100’s of nanometers. The feature size, shape, composition, orientation, and order all contribute to device efficiency and are simultaneously difficult to study due to poor contrast between carbon based materials. This study seeks to increase device efficiency and simplify morphology measurements by replacing the typical fullerene acceptor with endohedral fullerene Lu 3N@PC 80BEH. The metal atoms give excellent scattering contrast for electron beam and x-ray experiments. Additionally, Lu 3N@PC 80BEH has a lower electron affinity than standard fullerenes, which can raise the open circuit voltage of photovoltaicmore » devices. Electron microscopy techniques are used to produce a detailed account of morphology evolution in mixtures of Lu 3N@PC 80BEH with the record breaking donor polymer, PTB7 and coated using solvent mixtures. We demonstrate that common solvent additives like 1,8-diiodooctane or chloronapthalene do not improve the morphology of endohedral fullerene devices as expected. The poor device performance is attributed to the lack of mutual miscibility between this particular polymer:fullerene combination and to co-crystallization of Lu 3N@PC 80BEH with 1,8-diiodooctane. This negative result explains why solvent additives mixtures are not necessarily a morphology cure-all.« less

Synthesis, crystal structure, Hirshfeld surfaces analysis and anti-ischemic activity of cinnamide derivatives

NASA Astrophysics Data System (ADS)

Zhong, Jian-gang; Han, Jia-pei; Li, Xiao-feng; Xu, Yi; Zhong, Yan; Wu, Bin

2018-02-01

Two cinnamide derivatives, namely, (E)-1-(4-(bis(4-methylphenyl)- methyl)piperazin-1-yl)-3-(3,4-diethoxyphenyl)prop-2-en-1-one (5) and (E)-1-(4-(bis- (4-fluorophenyl)methyl)piperazin-1-yl)-3-(4-methoxyphenyl)prop-2-en-1-one (6), have been synthesized and characterized by IR spectra, High resolution mass spectra, 1H NMR spectra, 13C NMR spectra. The compound 5 is a novel compound and has never been reported in the literature. Their crystal structures were studied by single-crystal X-ray diffraction. They all crystallize in the monoclinic system. The single-crystal X-ray revealed that compound 5 has infinite X-shaped 1-D polymeric chains structure and compound 6 has a layered 3-D structure by intermolecular interactions. Hirshfeld surface analysis demonstrated the presence of H⋯H, O⋯H, C⋯H, F⋯H, Csbnd H⋯π and π⋯π intermolecular interactions. In addition, the MTT assay results indicated that the compounds 5 and 6 display effective activities against neurotoxicity which is induced by glutamine in PC12 cells. The in vivo experiment indicated that the compound 6 has a good protective effect on cerebral infarction.

Experimental study on dynamic mechanical behaviors of polycarbonate

NASA Astrophysics Data System (ADS)

Zhang, Wei; Gao, Yubo; Ye, Nan; Huang, Wei; Li, Dacheng

2017-01-01

Polycarbonate (PC) is a widely used engineering material in aerospace field, since it has excellent mechanical and optical property. In present study, both compressive and tensile tests of PC were conducted at high strain rates by using a split Hopkinson pressure bar. The high-speed camera and 2D Digital Image Correlation method (DIC) were used to analyze the dynamic deformation behavior of PC. Meanwhile, the plate impact experiment was carried out to measure the equation of state of PC in a single-stage gas gun, which consists of asymmetric impact technology, manganin gauges, PVDF, electromagnetic particle velocity gauges. The results indicate that the yield stress of PC increased with the strain rates in both dynamic compression and tension tests. The same phenomenon was similar to elasticity modulus at different strain rate. A constitutive model was used to describe the mechanical behaviors of PC accurately in different strain rates by contrast with the results of 2D-DIC. At last, The D-u Hugoniot curve of polycarbonate in high pressure was fitted by the least square method.

Magnetic properties in polycrystalline and single crystal Ca-doped LaCoO3

NASA Astrophysics Data System (ADS)

Zeng, R.; Debnath, J. C.; Chen, D. P.; Shamba, P.; Wang, J. L.; Kennedy, S. J.; Campbell, S. J.; Silver, T.; Dou, S. X.

2011-04-01

Polycrystalline (PC) and single crystalline (SC) Ca-doped LaCoO3 (LCCO) samples with the perovskite structure were synthesized by conventional solid-state reaction and the floating-zone growth method. We present the results of a comprehensive investigation of the magnetic properties of the LCCO system. Systematic measurements have been conducted on dc magnetization, ac susceptibility, exchange-bias, and the magnetocaloric effect. These findings suggest that complex structural phases, ferromagnetic (FM), and spin-glass/cluster-spin-glass (CSG), and their transitions exist in PC samples, while there is a much simpler magnetic phase in SC samples. It was also of interest to discover that the CSG induced a magnetic field memory effect and an exchange-bias-like effect, and that a large inverse irreversible magnetocaloric effect exists in this system.

Cupuassu (Theobroma grandiflorum) pulp, probiotic, and prebiotic: Influence on color, apparent viscosity, and texture of goat milk yogurts.

PubMed

Costa, Marion P; Frasao, Beatriz S; Silva, Adriana Cristina O; Freitas, Mônica Q; Franco, Robson M; Conte-Junior, Carlos A

2015-09-01

Cupuassu is an acidic fruit that has a characteristic aroma, flavor, and texture; its fiber-rich pulp can provide a different consistency than other fruit pulps. Goat milk is an excellent source of amino acids, fatty acids, and minerals, and is widely used for processing fermented milks, such as yogurt. However, compared with cow milk yogurts, it is difficult to make goat milk yogurts with a good consistency. Therefore, it is necessary to use certain technological strategies. This study was carried out to investigate the possibility of adding cupuassu pulp, probiotic (Lactobacillus acidophilus LA-5), and prebiotic (inulin) to improve the texture of goat milk yogurt. A total of 6 treatments were performed: natural (N), probiotic (Pro), prebiotic (Pre), synbiotic (S), cupuassu (C), and probiotic with cupuassu (PC). The viability of probiotic in yogurts (Pro, S, and PC) was evaluated. In addition, instrumental analyses (pH, color, apparent viscosity, and texture) were performed to evaluate the influence of these different ingredients on goat milk yogurts. The probiotic bacteria remained viable (≥7 log cfu·mL(-1)) throughout the 28d of refrigerated storage, which exceeded the minimum count required to confer probiotic physiological benefits. The pH levels of the yogurts inoculated with L. acidophilus (Pro, S, and PC) were lower than others yogurts (N, Pre, and C). However, all yogurt samples underwent gradual decreases in pH until 7 to 14d of storage. The lightness (L*) was affected initially by addition of all ingredients (cupuassu pulp, probiotic, and prebiotic). The addition of cupuassu pulp (C and PC) increased the L* during the period of storage. Apparent viscosity and firmness decreased in the PC yogurt. The consistency was highest in the yogurts with added prebiotic (Pre and S) than the other yogurts (N, Pro, C, and PC) at the end of the storage period (d 28). The cohesiveness remained constant in all yogurts (N, Pro, Pre, S, C, and PC). Based on the results obtained from the current study, it was concluded that cupuassu pulp addition improves the texture of goat milk yogurts. Therefore, this pulp could be an important technological strategy for the dairy goat industry. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Texturing of sodium bismuth titanate-barium titanate ceramics by templated grain growth

NASA Astrophysics Data System (ADS)

Yilmaz, Huseyin

2002-01-01

Sodium bismuth titanate modified with barium titanate, (Na1/2Bi 1/2)TiO3-BaTiO3 (NBT-BT), is a candidate lead-free piezoelectric material which has been shown to have comparatively high piezoelectric response. In this work, textured (Na1/2Bi1/2)TiO 3-BaTiO3 (5.5mol% BaTiO3) ceramics with <100> pc (where pc denotes the pseudocubic perovskite cell) orientation were fabricated by Templated Grain Growth (TGG) or Reactive Templated Grain Growth (RTGG) using anisotropically shaped template particles. In the case of TGG, molten salt synthesized SrTiO3 platelets were tape cast with a (Na1/2Bi1/2)TiO3-5.5mol%BaTiO3 powder and sintered at 1200°C for up to 12 hours. For the RTGG approach, Bi4Ti3O12 (BiT) platelets were tape cast with a Na2CO3, Bi2O3, TiO 2, and BaCO3 powder mixture and reactively sintered. The TGG approach using SrTiO3 templates gave stronger texture along [001] compared to the RTGG approach using BiT templates. The textured ceramics were characterized by X-ray and electron backscatter diffraction for the quality of texture. The texture function was quantified by the Lotgering factor, rocking curve, pole figures, inverse pole figures, and orientation imaging microscopy. Electrical and electromechanical property characterization of randomly oriented and <001>pc textured (Na1/2Bi1/2)TiO 3-5.5 mol% BaTiO3 rhombohedral ceramics showed 0.26% strain at 70 kV/cm, d33 coefficients over 500 pC/N have been obtained for highly textured samples (f ˜ 90%). The piezoelectric coefficient from Berlincourt was d33 ˜ 200 pC/N. The materials show considerable hysteresis. The presence of hysteresis in the unipolar-electric field curve is probably linked to the ferroelastic phase transition seen in the (Na 1/2Bi1/2)TiO3 system on cooling from high temperature at ˜520°C. The macroscopic physical properties (remanent polarization, dielectric constant, and piezoelectric coefficient) of random and textured ([001] pc) rhombohedral perovskites were estimated by linear averaging of single crystal data. However, the complete polarization, dielectric, and piezoelectric tensors are not available for NBT-BT single crystals. Therefore, the properties of lead based (PZT, 52/48) rhombohedral ferroelectric single domain-single crystals, whose properties (polarization, dielectric and piezoelectric) were computed using Landau-Ginsburg-Devonshire phenomenological theory (by Haun et. al.), were used in the calculations for random and textured cases. (Abstract shortened by UMI.)

Perseverative Cognition as an Explanatory Mechanism in the Relation Between Job Demands and Sleep Quality.

PubMed

Van Laethem, Michelle; Beckers, Debby G J; Geurts, Sabine A E; Garefelt, Johanna; Magnusson Hanson, Linda L; Leineweber, Constanze

2018-04-01

The aim of this longitudinal three-wave study was to examine (i) reciprocal associations among job demands, work-related perseverative cognition (PC), and sleep quality; (ii) PC as a mediator in-between job demands and sleep quality; and (iii) continuous high job demands in relation to sleep quality and work-related PC over time. A representative sample of the Swedish working population was approached in 2010, 2012, and 2014, and 2316 respondents were included in this longitudinal full-panel survey study. Structural equation modelling was performed to analyse the temporal relations between job demands, work-related PC, and sleep quality. Additionally, a subsample (N = 1149) consisting of individuals who reported the same level of exposure to job demands during all three waves (i.e. stable high, stable moderate, or stable low job demands) was examined in relation to PC and sleep quality over time. Analyses showed that job demands, PC, and poor sleep quality were positively and reciprocally related. Work-related PC mediated the normal and reversed, direct across-wave relations between job demands and sleep quality. Individuals with continuous high job demands reported significantly lower sleep quality and higher work-related PC, compared to individuals with continuous moderate/low job demands. This study substantiated reciprocal relations between job demands, work-related PC, and sleep quality and supported work-related PC as an underlying mechanism of the reciprocal job demands-sleep relationship. Moreover, this study showed that chronically high job demands are a risk factor for low sleep quality.

Aminophthalocyanine-Mediated Photodynamic Inactivation of Leishmania tropica

PubMed Central

Al-Qahtani, Ahmed; Alkahtani, Saad; Kolli, Bala; Tripathi, Pankaj; Dutta, Sujoy; Al-Kahtane, Abdullah A.; Jiang, Xiong-Jie; Ng, Dennis K. P.

2016-01-01

Photodynamic inactivation of Leishmania spp. requires the cellular uptake of photosensitizers, e.g., endocytosis of silicon(IV)-phthalocyanines (PC) axially substituted with bulky ligands. We report here that when substituted with amino-containing ligands, the PCs (PC1 and PC2) were endocytosed and displayed improved potency against Leishmania tropica promastigotes and axenic amastigotes in vitro. The uptake of these PCs by both Leishmania stages followed saturation kinetics, as expected. Sensitive assays were developed for assessing the photodynamic inactivation of Leishmania spp. by rendering them fluorescent in two ways: transfecting promastigotes to express green fluorescent protein (GFP) and loading them with carboxyfluorescein succinimidyl ester (CFSE). PC-sensitized Leishmania tropica strains were seen microscopically to lose their motility, structural integrity, and GFP/CFSE fluorescence after exposure to red light (wavelength, ∼650 nm) at a fluence of 1 to 2 J cm−2. Quantitative fluorescence assays based on the loss of GFP/CFSE from live Leishmania tropica showed that PC1 and PC2 dose dependently sensitized both stages for photoinactivation, consistent with the results of a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cell viability assay. Leishmania tropica strains are >100 times more sensitive than their host cells or macrophages to PC1- and PC2-mediated photoinactivation, judging from the estimated 50% effective concentrations (EC50s) of these cells. Axial substitution of the PC with amino groups instead of other ligands appears to increase its leishmanial photolytic activity by up to 40-fold. PC1 and PC2 are thus potentially useful for photodynamic therapy of leishmaniasis and for oxidative photoinactivation of Leishmania spp. for use as vaccines or vaccine carriers. PMID:26824938

Overexpression of microRNA-95-3p suppresses brain metastasis of lung adenocarcinoma through downregulation of cyclin D1.

PubMed

Hwang, Su Jin; Lee, Hye Won; Kim, Hye Ree; Song, Hye Jin; Lee, Dong Heon; Lee, Hong; Shin, Chang Hoon; Joung, Je-Gun; Kim, Duk-Hwan; Joo, Kyeung Min; Kim, Hyeon Ho

2015-08-21

Despite great efforts to improve survival rates, the prognosis of lung cancer patients is still very poor, mainly due to high invasiveness. We developed brain metastatic PC14PE6/LvBr4 cells through intracardiac injection of lung adenocarcinoma PC14PE6 cells. Western blot and RT-qPCR analyses revealed that PC14PE6/LvBr4 cells had mesenchymal characteristics and higher invasiveness than PC14PE6 cells. We found that cyclin D1 was upregulated, miR-95-3p was inversely downregulated, and pri-miR-95 and its host gene, ABLIM2, were consistently decreased in PC14PE6/LvBr4 cells. MiR-95-3p suppressed cyclin D1 expression through direct binding to the 3' UTR of cyclin D1 mRNA and suppressed invasiveness, proliferation, and clonogenicity of PC14PE6/LvBr4 cells. Ectopic cyclin D1 reversed miR-95-3p-mediated inhibition of invasiveness and clonogenicity, demonstrating cyclin D1 downregulation is involved in function of miR-95-3p. Using bioluminescence imaging, we found that miR-95-3p suppressed orthotopic tumorigenicity and brain metastasis in vivo and increased overall survival and brain metastasis-free survival. Consistent with in vitro metastatic cells, the levels of miR-95-3p, pri-miR-95, and ABLIM2 mRNA were decreased in brain metastatic tissues compared with lung cancer tissues and higher cyclin D1 expression was involved in poor prognosis. Taken together, our results demonstrate that miR-95-3p is a potential therapeutic target for brain metastasis of lung adenocarcinoma cells.

Relationship between in vitro assays and standardized ileal amino acid digestibility of animal protein meals in broilers.

PubMed

Rochell, S J; Kuhlers, D L; Dozier, W A

2013-01-01

Two identical trials were conducted to determine the relationship of a novel digestive enzyme assay, Poultry Complete IDEA (PC IDEA), and the pepsin digestibility assay with standardized ileal amino acid digestibility (SIAAD) of 20 animal protein meals (APM) fed to broilers from 25 to 30 d of age. Animal protein meals included 10 meat and bone meals (MBM) consisting of bovine, porcine, or mixed bovine and porcine raw materials (BP), and 10 animal protein blends containing animal proteins from various species. Treatments consisted of 20 semi-purified diets containing 1 APM as the sole source of dietary amino acids (AA), and 1 N-free diet to determine endogenous ileal AA flow. With the exception of the N-free diet, diets were formulated to contain 20% CP. In each trial, 756 Ross × Ross 708 male broilers were housed in battery cages and randomly assigned to 21 dietary treatments on d 25 (12 birds per cage; 3 replicate cages), and ileal digesta were collected on d 30 for determination of SIAAD. Pepsin digestibility and PC IDEA were determined for APM samples from each experimental diet (3 replicates per trial; 6 total replicates). Pepsin digestibility and PC IDEA were both correlated (P < 0.001) with SIAAD for each AA. Multiple linear regression of PC IDEA and pepsin digestibility on SIAAD resulted in the following equations: % Lys SIAAD = [-9.65 + (0.38 × % PC IDEA predicted Lys digestibility) + (0.69 × % pepsin digestibility)], % Met SIAAD = [-35.95 + (0.62 × % PC IDEA predicted Met digestibility) + (0.75 × % pepsin digestibility)], % Thr SIAAD = [-77.5 + (0.39 × % PC IDEA predicted Thr digestibility) + (1.37 × % pepsin digestibility)]. Values of R(2) were 0.46, 0.47, and 0.55 for Lys, Met, and Thr, respectively. The relatively low R(2) values may have been due to the limited range in SIAAD observed for the 20 APM, and additional data on APM varying in SIAAD are needed.

Compact Mach-Zehnder interferometer based on photonic crystal fiber and its application in switchable multi-wavelength fiber laser

NASA Astrophysics Data System (ADS)

Chen, Weiguo; Lou, Shuqin; Wang, Liwen; Li, Honglei; Guo, Tieying; Jian, Shuisheng

2009-08-01

The compact Mach-Zehnder interferometer is proposed by splicing a section of photonic crystal fiber (PCF) and two pieces of single mode fiber (SMF) with the air-holes of PCF intentionally collapsed in the vicinity of the splices. The depedence of the fringe spacing on the length of PCF is investigated. Based on the Mach-Zehnder interferometer as wavelength-selective filter, a switchable dual-wavelength fiber ring laser is demonstrated with a homemade erbiumdoped fiber amplifier (EDFA) as the gain medium at room temperature. By adjusting the states of the polarization controller (PC) appropriately, the laser can be switched among the stable single-and dual -wavelength lasing operations by exploiting polarization hole burning (PHB) effect.

Giant photonic Hall effect in magnetophotonic crystals.

PubMed

Merzlikin, A M; Vinogradov, A P; Inoue, M; Granovsky, A B

2005-10-01

We have considered a simple, square, two-dimensional (2D) PC built of a magneto-optic matrix with square holes. It is shown that using such a magnetophotonic crystal it is possible to deflect a light beam at very large angles by applying a nonzero external magnetic field. The effect is called the giant photonic Hall effect (GPHE) or the magnetic superprism effect. The GPHE is based on magneto-optical properties, as is the photonic Hall effect [B. A. van Tiggelen and G. L. J. A. Rikken, in, edited by V. M. Shalaev (Springer-Verlag, Berlin, 2002), p. 275]; however GPHE is not caused by asymmetrical light scattering but rather by the influence of an external magnetic field on the photonic band structure.

Individual Phosphatidylcholine Species Analysis by RP-HPLC-ELSD for Determination of Polyenylphosphatidylcholine in Lecithins.

PubMed

Lee, Wei-Ju; Weng, Shun-Hsiang; Su, Nan-Wei

2015-04-22

Polyenylphosphatidylcholine (PPC), a subgroup of the bioactive agents in phosphatidylcholine (PC), has been indicated to possess liver-protective effects. This study aimed to investigate a promising and feasible method to determine PC molecular species with a reverse phase (RP) high-performance liquid chromatograph (HPLC) equipped with an evaporative light scattering detector (ELSD). Chromatography was achieved using a C30 column and an isocratic mobile phase consisting of acetonitrile/methanol/triethylamine (40/58/2, v/v/v) at a flow rate of 1 mL/min, and ELSD detection was performed using 80 °C for the drift tube and an air flow rate of 1.8 L/min. To identify individual peaks on the chromatogram, MALDI-TOF-MS was employed for initial detection, and then the results were used to investigate the relationship between the retention time and fatty acyl chains of each PC molecule. A linear correlation was observed between the retention time and theoretical carbon number (TCN) of individual PC species. The compositions of PC molecular species in soybean and sunflower lecithins were similar to each other, and the major PC molecular species were 1,2-dilinoleoyl-sn-glycero-3-phosphocholine (LLPC), 1-oleoyl-2-linoleoyl-sn-glycero-3-phosphocholine (OLPC), and 1-palmitoyl-2-linoleoyl-sn-glycero-3-phosphocholine (PLPC). The contents of LLPC in soybean PC and sunflower PC were 40.6% and 64.3%, respectively.

Gene-by-Environment Interactions in Pancreatic Cancer: Implications for Prevention

PubMed Central

Jansen, Rick J.; Tan, Xiang-Lin; Petersen, Gloria M.

2015-01-01

Pancreatic cancer (PC) has been estimated to have higher incidence and correspondingly higher mortality rates in more developed regions worldwide. Overall, the age-adjusted incidence rate is 4.9/105 and age-adjusted mortality rate is at 4.8/105. We review here our current knowledge of modifiable risk factors (cigarette smoking, obesity, diet, and alcohol) for PC, genetic variants implicated by genome-wide association studies, possible genetic interactions with risk factors, and prevention strategies to provide future research directions that may further our understanding of this complex disease. Cigarette smoking is consistently associated with a two-fold increased PC risk. PC associations with dietary intake have been largely inconsistent, with the potential exception of certain unsaturated fatty acids decreasing risk and well-done red meat or meat mutagens increasing risk. There is strong evidence to support that obesity (and related measures) increase risk of PC. Only the heaviest alcohol drinkers seem to be at an increased risk of PC. Currently, key prevention strategies include avoiding tobacco and excessive alcohol consumption and adopting a healthy lifestyle. Screening technologies and PC chemoprevention are likely to become more sophisticated, but may only apply to those at high risk. Risk stratification may be improved by taking into account gene environment interactions. Research on these modifiable risk factors is key to reducing the incidence of PC and understanding who in the population can be considered high risk. PMID:26029010

Activation and deactivation of vibronic channels in intact phycocyanin rods.

PubMed

Nganou, C; David, L; Meinke, R; Adir, N; Maultzsch, J; Mkandawire, M; Pouhè, D; Thomsen, C

2014-02-28

We investigated the excitation modes of the light-harvesting protein phycocyanin (PC) from Thermosynechococcus vulcanus in the crystalline state using UV and near-infrared Raman spectroscopy. The spectra revealed the absence of a hydrogen out-of-plane wagging (HOOP) mode in the PC trimer, which suggests that the HOOP mode is activated in the intact PC rod, while it is not active in the PC trimer. Furthermore, in the PC trimer an intense mode at 984 cm(-1) is assigned to the C-C stretching vibration while the mode at 454 cm(-1) is likely due to ethyl group torsion. In contrast, in the similar chromophore phytochromobilin the C5,10,15-D wag mode at 622 cm(-1) does not come from a downshift of the HOOP. Additionally, the absence of modes between 1200 and 1300 cm(-1) rules out functional monomerization. A correlation between phycocyanobilin (PCB) and phycoerythrobilin (PEB) suggests that the PCB cofactors of the PC trimer appear in a conformation similar to that of PEB. The conformation of the PC rod is consistent with that of the allophycocyanin (APC) trimer, and thus excitonic flow is facilitated between these two independent light-harvesting compounds. This excitonic flow from the PC rod to APC appears to be modulated by the vibration channels during HOOP wagging, C = C stretching, and the N-H rocking in-plan vibration.

Fast modulations of pulsating proton aurora related to subpacket structures of Pc1 geomagnetic pulsations at subauroral latitudes

DOE PAGES

Ozaki, M.; Shiokawa, K.; Miyoshi, Y.; ...

2016-08-16

To understand the role of electromagnetic ion cyclotron (EMIC) waves in determining the temporal features of pulsating proton aurora (PPA) via wave-particle interactions at subauroral latitudes, high-time-resolution (1/8 s) images of proton-induced N 2>+ emissions were recorded using a new electron multiplying charge-coupled device camera, along with related Pc1 pulsations on the ground. The observed Pc1 pulsations consisted of successive rising-tone elements with a spacing for each element of 100 s and subpacket structures, which manifest as amplitude modulations with a period of a few tens of seconds. In accordance with the temporal features of the Pc1 pulsations, the auroralmore » intensity showed a similar repetition period of 100 s and an unpredicted fast modulation of a few tens of seconds. Furthermore, these results indicate that PPA is generated by pitch angle scattering, nonlinearly interacting with Pc1/EMIC waves at the magnetic equator.« less

Fast modulations of pulsating proton aurora related to subpacket structures of Pc1 geomagnetic pulsations at subauroral latitudes

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

Ozaki, M.; Shiokawa, K.; Miyoshi, Y.

To understand the role of electromagnetic ion cyclotron (EMIC) waves in determining the temporal features of pulsating proton aurora (PPA) via wave-particle interactions at subauroral latitudes, high-time-resolution (1/8 s) images of proton-induced N 2>+ emissions were recorded using a new electron multiplying charge-coupled device camera, along with related Pc1 pulsations on the ground. The observed Pc1 pulsations consisted of successive rising-tone elements with a spacing for each element of 100 s and subpacket structures, which manifest as amplitude modulations with a period of a few tens of seconds. In accordance with the temporal features of the Pc1 pulsations, the auroralmore » intensity showed a similar repetition period of 100 s and an unpredicted fast modulation of a few tens of seconds. Furthermore, these results indicate that PPA is generated by pitch angle scattering, nonlinearly interacting with Pc1/EMIC waves at the magnetic equator.« less

Regular Aspirin Use and the Risk of Lethal Prostate Cancer in the Physicians' Health Study.

PubMed

Downer, Mary K; Allard, Christopher B; Preston, Mark A; Gaziano, J Michael; Stampfer, Meir J; Mucci, Lorelei A; Batista, Julie L

2017-11-01

Regular aspirin use probably protects against some malignancies including prostate cancer (PC), but its impact on lethal PC is particularly unclear. To investigate the association between regular aspirin and (1) the risk of lethal PC in a large prospective cohort and (2) survival after PC diagnosis. In 1981/82, the Physicians' Health Study randomized 22 071 healthy male physicians to aspirin, β-carotene, both, or placebo. After the trial ended in 1988, annual questionnaires have obtained data on aspirin use, cancer diagnoses, and outcomes up to 2009 for the whole cohort, and to 2015 for PC patients. We evaluated the relationship between regular aspirin (>3 tablets/week) and lethal PC (metastases or PC death). Cox proportional-hazards models estimated hazard ratios (HRs) for the risk of lethal PC in the whole cohort and postdiagnosis survival among men initially diagnosed with nonlethal PC. Risk analysis revealed that 502 men developed lethal PC by 2009. Current and past regular aspirin was associated with a lower risk of lethal PC (current: HR 0.68, 95% confidence interval [CI] 0.52-0.89; past: HR 0.54, 95% CI 0.40-0.74) compared to never users. In the survival analysis, 407/3277 men diagnosed with nonlethal PC developed lethal disease by 2015. Current postdiagnostic aspirin was associated with lower risks of lethal PC (HR 0.68, 95% CI 0.52-0.90) and overall mortality (HR 0.72, 95% CI 0.61-0.9). We could not assess aspirin dose, and inconsistencies were observed in some sensitivity analyses. Current regular aspirin use was associated with a lower risk of lethal PC among all participants. Current postdiagnostic use was associated with improved survival after diagnosis, consistent with a potential inhibitory effect of aspirin on PC progression. A randomized trial is warranted to confirm or refute these findings. We examined the potential effect of regular aspirin use on lethal prostate cancer. We found that taking aspirin was associated with a lower risk of lethal prostate cancer, and taking it after diagnosis may help to prevent prostate cancer from becoming fatal. Copyright © 2017 European Association of Urology. Published by Elsevier B.V. All rights reserved.

Electrical conductivity and total dissolved solids in urine.

PubMed

Fazil Marickar, Y M

2010-08-01

The objective of this paper is to study the relevance of electrical conductivity (EC) and total dissolved solids (TDS) in early morning and random samples of urine of urinary stone patients; 2,000 urine samples were studied. The two parameters were correlated with the extent of various urinary concrements. The early morning urine (EMU) and random samples of the patients who attended the urinary stone clinic were analysed routinely. The pH, specific gravity, EC, TDS, redox potential, albumin, sugar and microscopic study of the urinary sediments including red blood cells (RBC), pus cells (PC), crystals, namely calcium oxalate monohydrate (COM), calcium oxalate dihydrate (COD), uric acid (UA), and phosphates and epithelial cells were assessed. The extent of RBC, PC, COM, COD, UA and phosphates was correlated with EC and TDS. The values of EC ranged from 1.1 to 33.9 mS, the mean value being 21.5 mS. TDS ranged from 3,028 to 18,480 ppm, the mean value being 7,012 ppm. The TDS levels corresponded with EC of urine. Both values were significantly higher (P < 0.05) in the EMU samples than the random samples. There was a statistically significant correlation between the level of abnormality in the urinary deposits (r = +0.27, P < 0.05). In samples, where the TDS were more than 12,000 ppm, there were more crystals than those samples containing TDS less than 12,000 ppm. However, there were certain urine samples, where the TDS were over 12,000, which did not contain any urinary crystals. It is concluded that the value of TDS has relevance in the process of stone formation.

Oxygen partial pressure effects on metabolic rate and behavior of tethered flying locusts.

PubMed

Rascón, Brenda; Harrison, Jon F

2005-11-01

Resting insects are extremely tolerant of hypoxia. However, oxygen requirements increase dramatically during flight. Does the critical atmospheric P (O)(2) (P(c)) increase strongly during flight, or does increased tracheal conductance allow even flying insects to possess large safety margins for oxygen delivery? We tested the effect of P(O)(2) on resting and flying CO(2) emission, as well as on flight behavior and vertical force production in flying locusts, Schistocerca americana. The P(c) for CO(2) emission of resting animals was less than 1 kPa, similar to prior studies. The P(c) for flight bout duration was between 10 and 21 kPa, the P(c) for vertical force production was between 3 and 5 kPa, and the P(c) for CO(2) emission was between 10 and 21 kPa. Our study suggests that the P(c) for steady-state oxygen consumption is between 10 and 21 kPa (much higher than for resting animals), and that tracheal oxygen stores allowed brief flights in 5 and 10 kPa P(O)(2) atmospheres to occur. Thus, P(c) values strongly increased during flight, consistent with the hypothesis that the excess oxygen delivery capacity observed in resting insects is substantially reduced during flight.

Small-molecule inhibitors of phosphatidylcholine transfer protein/StarD2 identified by high-throughput screening.

PubMed

Wagle, Neil; Xian, Jun; Shishova, Ekaterina Y; Wei, Jie; Glicksman, Marcie A; Cuny, Gregory D; Stein, Ross L; Cohen, David E

2008-12-01

Phosphatidylcholine transfer protein (PC-TP, also referred to as StarD2) is a highly specific intracellular lipid-binding protein that catalyzes the transfer of phosphatidylcholines between membranes in vitro. Recent studies have suggested that PC-TP in vivo functions to regulate fatty acid and glucose metabolism, possibly via interactions with selected other proteins. To begin to address the relationship between activity in vitro and biological function, we undertook a high-throughput screen to identify small-molecule inhibitors of the phosphatidylcholine transfer activity of PC-TP. After adapting a fluorescence quench assay to measure phosphatidylcholine transfer activity, we screened 114,752 compounds of a small-molecule library. The high-throughput screen identified 14 potential PC-TP inhibitors. Of these, 6 compounds exhibited characteristics consistent with specific inhibition of PC-TP activity, with IC(50) values that ranged from 4.1 to 95.0muM under conditions of the in vitro assay. These compounds should serve as valuable reagents to elucidate the biological function of PC-TP. Because mice with homozygous disruption of the PC-TP gene (Pctp) are sensitized to insulin action and relatively resistant to the development of atherosclerosis, these inhibitors may also prove to be of value in the management of diabetes and atherosclerotic cardiovascular diseases.

MR angiography of the renal artery: comparison of breath-hold two-dimensional phase-contrast cine technique with the phased-array coil and breath-hold two-dimensional time-of-flight technique with the body coil.

PubMed

Masui, T; Takehara, Y; Igarashi, T; Ichijo, K; Takahashi, M; Kaneko, M; Nozaki, A

1997-07-01

Breath-hold 2D phase-contrast (PC) cine MR angiography with a phased-array coil and 2D time-of-flight (TOF) MR angiography were performed in the renal arteries and their findings were compared. Breath-hold 2D thin slice PC and TOF MR angiography were performed in 10 normal volunteers for renal arteries. A PC technique with k-space segmentation was utilized with the phased-array coil. A PC technique provided visualization of the renal artery more distally than a TOF technique (4.8 +/- 0.5 cm vs. 3.7 +/- 0.8 cm). With cardiac triggering, distal renal arteries were well demonstrated in PC MR angiography. On PC images, up- or downward movements of the mid to distal renal arteries with aortic pulsatility were recognized. The quality of the images was better with the PC than with the TOF technique (3.4 vs. 2.7). The mid to distal portions of the renal arteries translationally move with aortic pulsatility. To consistently visualize and evaluate them on MR angiography, cardiac triggering might be required to reduce the effects of pulsatile motions of the renal artery in the use of a phased-array coil.

Severe congenital neutropenia resulting from G6PC3 deficiency with increased neutrophil CXCR4 expression and myelokathexis.

PubMed

McDermott, David H; De Ravin, Suk See; Jun, Hyun Sik; Liu, Qian; Priel, Debra A Long; Noel, Pierre; Takemoto, Clifford M; Ojode, Teresa; Paul, Scott M; Dunsmore, Kimberly P; Hilligoss, Dianne; Marquesen, Martha; Ulrick, Jean; Kuhns, Douglas B; Chou, Janice Y; Malech, Harry L; Murphy, Philip M

2010-10-14

Mutations in more than 15 genes are now known to cause severe congenital neutropenia (SCN); however, the pathologic mechanisms of most genetic defects are not fully defined. Deficiency of G6PC3, a glucose-6-phosphatase, causes a rare multisystem syndrome with SCN first described in 2009. We identified a family with 2 children with homozygous G6PC3 G260R mutations, a loss of enzymatic function, and typical syndrome features with the exception that their bone marrow biopsy pathology revealed abundant neutrophils consistent with myelokathexis. This pathologic finding is a hallmark of another type of SCN, WHIM syndrome, which is caused by gain-of-function mutations in CXCR4, a chemokine receptor and known neutrophil bone marrow retention factor. We found markedly increased CXCR4 expression on neutrophils from both our G6PC3-deficient patients and G6pc3(-/-) mice. In both patients, granulocyte colony-stimulating factor treatment normalized CXCR4 expression and neutrophil counts. In G6pc3(-/-) mice, the specific CXCR4 antagonist AMD3100 rapidly reversed neutropenia. Thus, myelokathexis associated with abnormally high neutrophil CXCR4 expression may contribute to neutropenia in G6PC3 deficiency and responds well to granulocyte colony-stimulating factor.

Analysis of the quantum numbers J(PC) of the X(3872) particle.

PubMed

Abulencia, A; Adelman, J; Affolder, T; Akimoto, T; Albrow, M G; Ambrose, D; Amerio, S; Amidei, D; Anastassov, A; Anikeev, K; Annovi, A; Antos, J; Aoki, M; Apollinari, G; Arguin, J-F; Arisawa, T; Artikov, A; Ashmanskas, W; Attal, A; Azfar, F; Azzi-Bacchetta, P; Azzurri, P; Bacchetta, N; Badgett, W; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Baroiant, S; Bartsch, V; Bauer, G; Bedeschi, F; Behari, S; Belforte, S; Bellettini, G; Bellinger, J; Belloni, A; Benjamin, D; Beretvas, A; Beringer, J; Berry, T; Bhatti, A; Binkley, M; Bisello, D; Blair, R E; Blocker, C; Blumenfeld, B; Bocci, A; Bodek, A; Boisvert, V; Bolla, G; Bolshov, A; Bortoletto, D; Boudreau, J; Boveia, A; Brau, B; Brigliadori, L; Bromberg, C; Brubaker, E; Budagov, J; Budd, H S; Budd, S; Budroni, S; Burkett, K; Busetto, G; Bussey, P; Byrum, K L; Cabrera, S; Campanelli, M; Campbell, M; Canelli, F; Canepa, A; Carillo, S; Carlsmith, D; Carosi, R; Casarsa, M; Castro, A; Catastini, P; Cauz, D; Cavalli-Sforza, M; Cerri, A; Cerrito, L; Chang, S H; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Chlebana, F; Cho, I; Cho, K; Chokheli, D; Chou, J P; Choudalakis, G; Chuang, S H; Chung, K; Chung, W H; Chung, Y S; Ciljak, M; Ciobanu, C I; Ciocci, M A; Clark, A; Clark, D; Coca, M; Compostella, G; Convery, M E; Conway, J; Cooper, B; Copic, K; Cordelli, M; Cortiana, G; Crescioli, F; Cuenca Almenar, C; Cuevas, J; Culbertson, R; Cully, J C; Cyr, D; Daronco, S; Datta, M; D'Auria, S; Davies, T; D'Onofrio, M; Dagenhart, D; de Barbaro, P; De Cecco, S; Deisher, A; De Lentdecker, G; Dell'Orso, M; Delli Paoli, F; Demortier, L; Deng, J; Deninno, M; De Pedis, D; Derwent, P F; Di Giovanni, G P; Dionisi, C; Di Ruzza, B; Dittmann, J R; DiTuro, P; Dörr, C; Donati, S; Donega, M; Dong, P; Donini, J; Dorigo, T; Dube, S; Efron, J; Erbacher, R; Errede, D; Errede, S; Eusebi, R; Fang, H C; Farrington, S; Fedorko, I; Fedorko, W T; Feild, R G; Feindt, M; Fernandez, J P; Field, R; Flanagan, G; Foland, A; Forrester, S; Foster, G W; Franklin, M; Freeman, J C; Furic, I; Gallinaro, M; Galyardt, J; Garcia, J E; Garberson, F; Garfinkel, A F; Gay, C; Gerberich, H; Gerdes, D; Giagu, S; Giannetti, P; Gibson, A; Gibson, K; Gimmell, J L; Ginsburg, C; Giokaris, N; Giordani, M; Giromini, P; Giunta, M; Giurgiu, G; Glagolev, V; Glenzinski, D; Gold, M; Goldschmidt, N; Goldstein, J; Golossanov, A; Gomez, G; Gomez-Ceballos, G; Goncharov, M; González, O; Gorelov, I; Goshaw, A T; Goulianos, K; Gresele, A; Griffiths, M; Grinstein, S; Grosso-Pilcher, C; Grundler, U; Guimaraes da Costa, J; Gunay-Unalan, Z; Haber, C; Hahn, K; Hahn, S R; Halkiadakis, E; Hamilton, A; Han, B-Y; Han, J Y; Handler, R; Happacher, F; Hara, K; Hare, M; Harper, S; Harr, R F; Harris, R M; Hartz, M; Hatakeyama, K; Hauser, J; Heijboer, A; Heinemann, B; Heinrich, J; Henderson, C; Herndon, M; Heuser, J; Hidas, D; Hill, C S; Hirschbuehl, D; Hocker, A; Holloway, A; Hou, S; Houlden, M; Hsu, S-C; Huffman, B T; Hughes, R E; Husemann, U; Huston, J; Incandela, J; Introzzi, G; Iori, M; Ishizawa, Y; Ivanov, A; Iyutin, B; James, E; Jang, D; Jayatilaka, B; Jeans, D; Jensen, H; Jeon, E J; Jindariani, S; Jones, M; Joo, K K; Jun, S Y; Jung, J E; Junk, T R; Kamon, T; Karchin, P E; Kato, Y; Kemp, Y; Kephart, R; Kerzel, U; Khotilovich, V; Kilminster, B; Kim, D H; Kim, H S; Kim, J E; Kim, M J; Kim, S B; Kim, S H; Kim, Y K; Kimura, N; Kirsch, L; Klimenko, S; Klute, M; Knuteson, B; Ko, B R; Kondo, K; Kong, D J; Konigsberg, J; Korytov, A; Kotwal, A V; Kovalev, A; Kraan, A C; Kraus, J; Kravchenko, I; Kreps, M; Kroll, J; Krumnack, N; Kruse, M; Krutelyov, V; Kubo, T; Kuhlmann, S E; Kuhr, T; Kusakabe, Y; Kwang, S; Laasanen, A T; Lai, S; Lami, S; Lammel, S; Lancaster, M; Lander, R L; Lannon, K; Lath, A; Latino, G; Lazzizzera, I; LeCompte, T; Lee, J; Lee, J; Lee, Y J; Lee, S W; Lefèvre, R; Leonardo, N; Leone, S; Levy, S; Lewis, J D; Lin, C; Lin, C S; Lindgren, M; Lipeles, E; Lister, A; Litvintsev, D O; Liu, T; Lockyer, N S; Loginov, A; Loreti, M; Loverre, P; Lu, R-S; Lucchesi, D; Lujan, P; Lukens, P; Lungu, G; Lyons, L; Lys, J; Lysak, R; Lytken, E; Mack, P; MacQueen, D; Madrak, R; Maeshima, K; Makhoul, K; Maki, T; Maksimovic, P; Malde, S; Manca, G; Margaroli, F; Marginean, R; Marino, C; Marino, C P; Martin, A; Martin, M; Martin, V; Martínez, M; Maruyama, T; Mastrandrea, P; Masubuchi, T; Matsunaga, H; Mattson, M E; Mazini, R; Mazzanti, P; McFarland, K S; McIntyre, P; McNulty, R; Mehta, A; Mehtala, P; Menzemer, S; Menzione, A; Merkel, P; Mesropian, C; Messina, A; Miao, T; Miladinovic, N; Miles, J; Miller, R; Mills, C; Milnik, M; Mitra, A; Mitselmakher, G; Miyamoto, A; Moed, S; Moggi, N; Mohr, B; Moore, R; Morello, M; Movilla Fernandez, P; Mülmenstädt, J; Mukherjee, A; Muller, Th; Mumford, R; Murat, P; Nachtman, J; Nagano, A; Naganoma, J; Nakano, I; Napier, A; Necula, V; Neu, C; Neubauer, M S; Nielsen, J; Nigmanov, T; Nodulman, L; Norniella, O; Nurse, E; Oh, S H; Oh, Y D; Oksuzian, I; Okusawa, T; Oldeman, R; Orava, R; Osterberg, K; Pagliarone, C; Palencia, E; Papadimitriou, V; Paramonov, A A; Parks, B; Pashapour, S; Patrick, J; Pauletta, G; Paulini, M; Paus, C; Pellett, D E; Penzo, A; Phillips, T J; Piacentino, G; Piedra, J; Pinera, L; Pitts, K; Plager, C; Pondrom, L; Portell, X; Poukhov, O; Pounder, N; Prakoshyn, F; Pronko, A; Proudfoot, J; Ptohos, F; Punzi, G; Pursley, J; Rademacker, J; Rahaman, A; Ranjan, N; Rappoccio, S; Reisert, B; Rekovic, V; Renton, P; Rescigno, M; Richter, S; Rimondi, F; Ristori, L; Robson, A; Rodrigo, T; Rogers, E; Rolli, S; Roser, R; Rossi, M; Rossin, R; Ruiz, A; Russ, J; Rusu, V; Saarikko, H; Sabik, S; Safonov, A; Sakumoto, W K; Salamanna, G; Saltó, O; Saltzberg, D; Sánchez, C; Santi, L; Sarkar, S; Sartori, L; Sato, K; Savard, P; Savoy-Navarro, A; Scheidle, T; Schlabach, P; Schmidt, E E; Schmidt, M P; Schmitt, M; Schwarz, T; Scodellaro, L; Scott, A L; Scribano, A; Scuri, F; Sedov, A; Seidel, S; Seiya, Y; Semenov, A; Sexton-Kennedy, L; Sfyrla, A; Shapiro, M D; Shears, T; Shepard, P F; Sherman, D; Shimojima, M; Shochet, M; Shon, Y; Shreyber, I; Sidoti, A; Sinervo, P; Sisakyan, A; Sjolin, J; Slaughter, A J; Slaunwhite, J; Sliwa, K; Smith, J R; Snider, F D; Snihur, R; Soderberg, M; Soha, A; Somalwar, S; Sorin, V; Spalding, J; Spinella, F; Spreitzer, T; Squillacioti, P; Stanitzki, M; Staveris-Polykalas, A; St Denis, R; Stelzer, B; Stelzer-Chilton, O; Stentz, D; Strologas, J; Stuart, D; Suh, J S; Sukhanov, A; Sun, H; Suzuki, T; Taffard, A; Takashima, R; Takeuchi, Y; Takikawa, K; Tanaka, M; Tanaka, R; Tecchio, M; Teng, P K; Terashi, K; Thom, J; Thompson, A S; Thomson, E; Tipton, P; Tiwari, V; Tkaczyk, S; Toback, D; Tokar, S; Tollefson, K; Tomura, T; Tonelli, D; Torre, S; Torretta, D; Tourneur, S; Trischuk, W; Tsuchiya, R; Tsuno, S; Turini, N; Ukegawa, F; Unverhau, T; Uozumi, S; Usynin, D; Vallecorsa, S; van Remortel, N; Varganov, A; Vataga, E; Vázquez, F; Velev, G; Veramendi, G; Veszpremi, V; Vidal, R; Vila, I; Vilar, R; Vine, T; Vollrath, I; Volobouev, I; Volpi, G; Würthwein, F; Wagner, P; Wagner, R G; Wagner, R L; Wagner, J; Wagner, W; Wallny, R; Wang, S M; Warburton, A; Waschke, S; Waters, D; Wester, W C; Whitehouse, B; Whiteson, D; Wicklund, A B; Wicklund, E; Williams, G; Williams, H H; Wilson, P; Winer, B L; Wittich, P; Wolbers, S; Wolfe, C; Wright, T; Wu, X; Wynne, S M; Yagil, A; Yamamoto, K; Yamaoka, J; Yamashita, T; Yang, C; Yang, U K; Yang, Y C; Yao, W M; Yeh, G P; Yoh, J; Yorita, K; Yoshida, T; Yu, G B; Yu, I; Yu, S S; Yun, J C; Zanello, L; Zanetti, A; Zaw, I; Zhang, X; Zhou, J; Zucchelli, S

2007-03-30

We present an analysis of angular distributions and correlations of the X(3872) particle in the exclusive decay mode X(3872)-->J/psipi+ pi- with J/psi-->mu+ mu-. We use 780 pb-1 of data from pp[over ] collisions at sqrt[s]=1.96 TeV collected with the CDF II detector at the Fermilab Tevatron. We derive constraints on spin, parity, and charge conjugation parity of the X(3872) particle by comparing measured angular distributions of the decay products with predictions for different J(PC) hypotheses. The assignments J(PC)=1++ and 2-+ are the only ones consistent with the data.

Chemical pressure tuning of URu2Si2 via isoelectronic substitution of Ru with Fe

NASA Astrophysics Data System (ADS)

Das, Pinaki; Kanchanavatee, N.; Helton, J. S.; Huang, K.; Baumbach, R. E.; Bauer, E. D.; White, B. D.; Burnett, V. W.; Maple, M. B.; Lynn, J. W.; Janoschek, M.

2015-02-01

We have used specific heat and neutron diffraction measurements on single crystals of URu2 -xFexSi2 for Fe concentrations x ≤0.7 to establish that chemical substitution of Ru with Fe acts as "chemical pressure" Pc h as previously proposed by Kanchanavatee et al. [Phys. Rev. B 84, 245122 (2011), 10.1103/PhysRevB.84.245122] based on bulk measurements on polycrystalline samples. Notably, neutron diffraction reveals a sharp increase of the uranium magnetic moment at x =0.1 , reminiscent of the behavior at the "hidden order" to large-moment-antiferromagnetic phase transition observed at a pressure Px≈0.5 -0.7 GPa in URu2Si2 . Using the unit-cell volume determined from our measurements and an isothermal compressibility κT=5.2 ×10-3 GPa-1 for URu2Si2 , we determine the chemical pressure Pc h in URu2 -xFexSi2 as a function of x . The resulting temperature (T )-chemical pressure (Pc h) phase diagram for URu2 -xFexSi2 is in agreement with the established temperature (T )-external pressure (P ) phase diagram of URu2Si2 .

Coordination chemistry of 2,2'-biphenylenedithiophosphinate and diphenyldithiophosphinate with U, Np, and Pu

DOE PAGES

Macor, Joseph A.; Brown, Jessie L.; Cross, Justin Neil; ...

2015-01-01

New members of the dithiophosphinic acid family of potential actinide extractants were prepared: heterocyclic 2,2'-biphenylenedithiophosphinic acids of stoichiometry HS 2P(R 2C 12H 6) (R = H or tBu). The time- and atom-efficient syntheses afforded multigram quantities of pure HS 2P(R 2C 12H 6) in reasonable yields (~60%). These compounds differed from other diaryldithiophosphinic acid extractants in that the two aryl groups were connected to one another at the ortho positions to form a 5-membered dibenzophosphole ring. These 2,2'-biphenylenedithiophosphinic acids were readily deprotonated to form S 2P(R 2C 12H 6) 1- anions, which were crystallized as salts with tetraphenylpnictonium cations (ZPhmore » 4 1+; Z = P or As). Coordination chemistry between [S 2P( tBu 2C 12H 6)] 1- and [S 2P(C 6H 5)2] 1- with U, Np, and Pu was comparatively investigated. The results showed that dithiophosphinate complexes of UIV and NpIV were redox stable relative to those of UIII, whereas reactions involving PuIV gave intractable material. For instance, reactions involving UIV and NpIV generated An[S 2P( tBu 2C 12H 6)] 4 and An[S 2P(C 6H 5) 2] 4 whereas reactions between PuIV and [S 2P(C 6H 5) 2] 1- generated a mixture of products from which we postulated a transient PuIII species based on UV-Vis spectroscopy. However, the trivalent Pu[S 2P(C 6H 5) 2] 3(NC 5H 5) 2 compound is stable and could be isolated from reactions between [S 2P(C 6H 5) 2] 1- and the trivalent PuI 3(NC 5H 5) 4 starting material. Attempts to synthesize analogous trivalent compounds with UIII provided the tetravalent U[S 2P(C 6H 5 )2] 4 oxidation product.« less

The Intermediate Stellar Mass Population in R136 Determined from Hubble Space Telescope Planetary Camera 2 Images

NASA Astrophysics Data System (ADS)

Hunter, Deidre A.; Shaya, Edward J.; Holtzman, Jon A.; Light, Robert M.; O'Neil, Earl J., Jr.; Lynds, Roger

1995-07-01

We have analyzed Hubble Space Telescope (HST) images of the compact, luminous star cluster R136 in the LMC that were taken with the refurbished HST and new Wide Field/Planetary Camera. These images allow us to examine the stellar population in a region of unusually intense star formation at a scale of 0.01 pc. We have detected stars to 23.5 in F555W and have quantified the stellar population to an M555,0 of 0.9 or a mass of 2.8 Msun. Comparisons of HR diagrams with isochrones that were constructed for the HST flight filter system from theoretical stellar evolutionary tracks reveal massive stars, a main sequence to at least 2.8 Msun, and stars with M555,0 ≥ 0.5 still on pre-main sequence tracks. The average stellar population is fit with a 3-4 Myr isochrone. Contrary to expectations from star formation models, however, the formation period for the massive stars and lower mass stars appear to largely overlap. We have measured the IMF for stars 2.8-15 Msun in three annuli from 0.5-4.7 pc from the center of the cluster. The slopes of the IMF in all three annuli are the same within the uncertainties, thus, showing no evidence for mass segregation beyond 0.5 pc. Furthermore, the combined IMF slope, -122±006 is close to a normal Salpeter IMF. The lower mass limit must be lower than the limits of our measurements: ≤ 2.8 Msun beyond 0.5 pc and ≤ 7 Msun within 0.1 pc. This is contrary to some predictions that the lower mass limit could be as high as 10 Msun in regions of intense massive star formation. Integrated properties of R136 are consistent with its being comparable to a rather small globular cluster when such clusters were the same age as R136. From the surface brightness profile, an upper limit for the core radius of 0.02 pc is set. Within a radius of 0.4 pc we estimate that there have been roughly 20 crossing times and relaxation should be well along. Within 0.5 pc crowding prevents us from detecting the intermediate mass population, but there is a hint of an excess of stars brighter than M555,0 = -5 and of a deficit in the highest mass stars between 0.6 pc and 1.2 pc. This would be consistent with dynamical segregation.

VizieR Online Data Catalog: HST photometry in R136 (Hunter+ 1995)

NASA Astrophysics Data System (ADS)

Hunter, D. A.; Shaya, E. J.; Holtzman, J. A.; Light, R. M.; Oneil, Earl J., Jr.

1996-01-01

We have analyzed Hubble Space Telescope (HST) images of the compact, luminous star cluster R136 in the LMC that were taken with the refurbished HST and new Wide Field/Planetary Camera. These images allow us to examine the stellar population in a region of unusually intense star formation at a scale of 0.01pc. We have detected stars to 23.5 in F555W and have quantified the stellar population to an M_555.0 of 0.9 or a mass of 2.8M⊙. Comparisons of HR diagrams with isochrones that were constructed for the HST flight filter system from theoretical stellar evolutionary tracks reveal massive stars, a main sequence to at least 2.8M⊙, and stars with M_555.0>=0.5 still on pre-main sequence tracks. The average stellar population is fit with a 3-4Myr isochrone. Contrary to expectations from star formation models, however, the formation period for the massive stars and lower mass stars appear to largely overlap. We have measured the IMF for stars 2.8-15M⊙ in three annuli from 0.5-4.7pc from the center of the cluster. The slopes of the IMF in all three annuli are the same within the uncertainties, thus, showing no evidence for mass segregation beyond 0.5pc. Furthermore, the combined IMF slope, -1.22+/-0.06, is close to a normal Salpeter IMF. The lower mass limit must be lower than the limits of our measurements: <=2.8M⊙ beyond 0.5pc and <=7M⊙ within 0.1pc. This is contrary to some predictions that the lower mass limit could be as high as 10M⊙ in regions of intense massive star formation. Integrated properties of R136 are consistent with its being comparable to a rather small globular cluster when such clusters were the same age as R136. From the surface brightness profile, an upper limit for core radius of 0.02pc is set. Within a radius of 0.4pc we estimate that there have been roughly 20 crossing times and relaxation should be well along. Within 0.5pc crowding prevents us from detecting the intermediate mass population, but there is a hint of an excess of stars brighter than M_555.0=-5 and of a deficit in the highest mass stars between 0.6pc and 1.2pc. This would be consistent with dynamical segregation. (1 data file).

Evaluation of increasing levels of a microbial phytase in phosphorus deficient broiler diets via live broiler performance, tibia bone ash, apparent metabolizable energy, and amino acid digestibility.

PubMed

Pieniazek, J; Smith, K A; Williams, M P; Manangi, M K; Vazquez-Anon, M; Solbak, A; Miller, M; Lee, J T

2017-02-01

The objective was to investigate increasing concentrations of an evolved microbial phytase on male broiler performance, tibia bone ash, AME, and amino acid digestibility when fed diets deficient in available phosphorus (aP). Experiment 1 evaluated the effects of phytase during a 21 d battery cage study and Experiment 2 was a 42 d grow-out. Experiment 1 included six treatments; negative control (NC) with an aP level of 0.23% (starter) and 0.19% (grower), two positive controls (PC) consisting of an additional 0.12% and 0.22% aP (PC 1 and PC 2), and the NC supplemented with three levels of phytase (250, 500, and 2,000 U/kg). The NC diet reduced (P < 0.05) FC, BW, and bone ash. Phytase increased (P < 0.05) BW with 2,000 U/kg phytase yielding similar results to the PC2, and improved FCR and increased bone ash was observed at all phytase levels. Amino acid digestibility coefficients were increased (P < 0.05) with phytase at 250 U/kg. Phytase at all rates increased (P < 0.05) AME to levels similar level as PC diets. Linear regression analysis indicated average P equivalency values for BW and bone ash of 0.137, 0.147, and 0.226 for phytase inclusion of 250, 500, and 2000 U/kg, respectively. Experiment 2 included a PC consisting of 0.45%, 0.41%, and 0.38% aP for the starter, grower, and finisher, respectively; NC with reduced aP of 0.17%; and phytase at 500 and 2,000 U/kg. Phytase increased BW (P < 0.05) compared to the NC as 2,000 U/kg phytase resulted in further BW increases compared to the PC (starter and grower). Phytase improved FCR to levels comparable to the PC, with supplementation at 2,000 U/kg resulting in improvements beyond the PC in the starter phase. Amino acid digestibility coefficients were increased with phytase at 2,000 U/kg to levels comparable to that of the PC. These data confirm that the inclusion of phytase improves broiler performance and bone mineralization in aP reduced diets and levels beyond the traditional 500 U/kg can result in further improvements. © 2016 Poultry Science Association Inc.

An Extremely Red and Two Other Nearby L Dwarf Candidates Previously Overlooked in 2MASS, WISE, and Other Surveys

NASA Astrophysics Data System (ADS)

Scholz, Ralf-Dieter; Bell, Cameron P. M.

2018-02-01

We present three new nearby L dwarf candidates, found in a continued combined color/proper motion search using WISE, 2MASS, and other survey data, where we included extended WISE sources and looked closer to the Galactic plane region. Their spectral types and distances were estimated from photometric comparisons to well-known L dwarfs with trigonometric parallaxes. The first object, 2MASS J07555430-3259589, is an extremely red L7.5p dwarf candidate at a photometric distance of about 16 pc. Its position, proper motion and distance are consistent with membership in the Carina-Near young moving group. The second one, 2MASS J07414279-0506464, is resolved in Gaia DR1 as a close binary (separation 0.3 arcsec), and we classify it as a equal-mass binary candidate consisting of two L5 dwarfs at 19 pc. Our nearest new neighbor, 2MASS J19251275+0700362, is an L7 dwarf candidate at 10 pc.

Imaging the 'mosaic' structure of ICB by pre-critical PcP-PKiKP phases

NASA Astrophysics Data System (ADS)

Shen, Z.; Ai, Y.; He, Y.; Jiang, M.

2013-12-01

Slowly growing in highly homogeneous liquid outer core, earth inner core has been thought lacking of significant heterogeneous structure. However, seismic observations of recent decades have demonstrated hierarchical heterogeneous structure as hemispherical longitudinal dichotomy superimposed by coda-generating scattering heterogeneities with diameters of tens of kilometers, indicating complicity of inner core crystallizing environment and related dynamic process. Furthermore, as boundary of phase transform and energy-material exchange, ICB has been unveiled as patchy mosaic-like surface, based on high variety of global pre-critical PcP-PKiKP amplitude ratios. From dense arrays deployed across East and South China in the year 2005~2011 and 13 earthquakes of west Pacific subduction zone, we have collected over 150 clear pre-critical PcP-PKiKP waveforms of epicenter distance range between 14~35°, providing an ideal sampling to detect possible ICB regional variation of the East Asia area. The amplitude observation exhibits good geographical coherency which is characterized as region of high density contrast (>1.0g/cm3) located beneath East China demarcated by the low (around or lower than 0.6g/cm3) on the periphery, except the southeastward stretching. This contrasting depicts vividly the claimed 'mosaic' ICB and bridges the gap between hemispherical (~1000km order) and scatter-inducing (~10km order or less) scales of heterogeneity. On the other hand, travel time residues of PcP-PKiKP in our study reveal a complex pattern north of ~18°N perturbed strongly by shallow (crust and mantle) anomalies and remarkable delay of PKiKP in the south, implicating effects of undetected ULVZ below Celebes Sea. This research is supported by the National Natural Science Foundation of China (NSFC, grant 90914011, 41125015). Distribution of PcP-PKiKP relative amplitude ratio

Emergency medicine resident education in palliative care: a needs assessment.

PubMed

Lamba, Sangeeta; Pound, Amy; Rella, Joseph G; Compton, Scott

2012-05-01

Hospice and Palliative Medicine is a newly designated subspecialty of Emergency Medicine (EM). As yet, no well defined palliative care (PC) models for education or training exist. A needs assessment is the first step towards developing a curriculum. To characterize emergency physicians' (EP) perceived educational and formal training needs for PC related skills. All EM residents and faculty of one academic facility were asked to complete an anonymous needs-assessment survey. Participants were asked to rank statements related to attitudes about PC and rate their formal training and knowledge in 10 aspects of PC using a 5-point Likert-scale. EPs also ranked 4 learning modalities in order of preference and 12 PC educational topics in order of perceived importance in an EM curriculum. Ninety-three percent (42/45) of eligible participants completed the survey (28 residents, 14 faculty). Respondents agreed/strongly agreed that PC skills are an important competence for EM (88%, 37/42) and that they would "like to have more training/education in PC" (79%, 33/42). Respondents also disagreed/strongly disagreed with the statement that "PC consult is called when no more can be done for the patient" (90%, 38/42). Important PC topics identified were pain management, discussing code status, and management of dyspnea and other symptoms in terminal illness. Bedside teaching was listed as the preferred learning modality. EM residents reported minimal training in pain management (46%, 13/28), managing hospice patients (54%, 15/28), withdrawal/withholding life support (54%, 15/28), and managing the imminently dying (43%, 12/28). There was no consistent, significant improvement reported in any domain as training and experience progressed from PGY (postgraduate year) 1 to PGY 4 to attending physician. EPs view PC skills as important for EM practice and report that they are not yet adequately educated and trained in providing PC. Domains of particular interest and targeted areas for PC skills training for EPs may include managing hospice patients, withdrawal of life support, prognostication, and pain management.

PV-Diesel Hybrid SCADA Experiment Network Design

NASA Technical Reports Server (NTRS)

Kalu, Alex; Durand, S.; Emrich, Carol; Ventre, G.; Wilson, W.; Acosta, R.

1999-01-01

The essential features of an experimental network for renewable power system satellite based supervisory, control and data acquisition (SCADA) are communication links, controllers, diagnostic equipment and a hybrid power system. Required components for implementing the network consist of two satellite ground stations, to satellite modems, two 486 PCs, two telephone receivers, two telephone modems, two analog telephone lines, one digital telephone line, a hybrid-power system equipped with controller and a satellite spacecraft. In the technology verification experiment (TVE) conducted by Savannah State University and Florida Solar Energy Center, the renewable energy hybrid system is the Apex-1000 Mini-Hybrid which is equipped with NGC3188 for user interface and remote control and the NGC2010 for monitoring and basic control tasks. This power system is connected to a satellite modem via a smart interface, RS232. Commands are sent to the power system control unit through a control PC designed as PC1. PC1 is thus connected to a satellite model through RS232. A second PC, designated PC2, the diagnostic PC is connected to both satellite modems via separate analog telephone lines for checking modems'health. PC2 is also connected to PC1 via a telephone line. Due to the unavailability of a second ground station for the ACTS, one ground station is used to serve both the sending and receiving functions in this experiment. Signal is sent from the control PC to the Hybrid system at a frequency f(sub 1), different from f(sub 2), the signal from the hybrid system to the control PC. f(sub l) and f(sub 2) are sufficiently separated to avoid interference.

Isolation of Novel Synthetic Prion Strains by Amplification in Transgenic Mice Coexpressing Wild-Type and Anchorless Prion Proteins

PubMed Central

Raymond, Gregory J.; Race, Brent; Hollister, Jason R.; Offerdahl, Danielle K.; Moore, Roger A.; Kodali, Ravindra; Raymond, Lynne D.; Hughson, Andrew G.; Rosenke, Rebecca; Long, Dan; Dorward, David W.

2012-01-01

Mammalian prions are thought to consist of misfolded aggregates (protease-resistant isoform of the prion protein [PrPres]) of the cellular prion protein (PrPC). Transmissible spongiform encephalopathy (TSE) can be induced in animals inoculated with recombinant PrP (rPrP) amyloid fibrils lacking mammalian posttranslational modifications, but this induction is inefficient in hamsters or transgenic mice overexpressing glycosylphosphatidylinositol (GPI)-anchored PrPC. Here we show that TSE can be initiated by inoculation of misfolded rPrP into mice that express wild-type (wt) levels of PrPC and that synthetic prion strain propagation and selection can be affected by GPI anchoring of the host's PrPC. To create prions de novo, we fibrillized mouse rPrP in the absence of molecular cofactors, generating fibrils with a PrPres-like protease-resistant banding profile. These fibrils induced the formation of PrPres deposits in transgenic mice coexpressing wt and GPI-anchorless PrPC (wt/GPI−) at a combined level comparable to that of PrPC expression in wt mice. Secondary passage into mice expressing wt, GPI−, or wt plus GPI− PrPC induced TSE disease with novel clinical, histopathological, and biochemical phenotypes. Contrary to laboratory-adapted mouse scrapie strains, the synthetic prion agents exhibited a preference for conversion of GPI− PrPC and, in one case, caused disease only in GPI− mice. Our data show that novel TSE agents can be generated de novo solely from purified mouse rPrP after amplification in mice coexpressing normal levels of wt and anchorless PrPC. These observations provide insight into the minimal elements required to create prions in vitro and suggest that the PrPC GPI anchor can modulate the propagation of synthetic TSE strains. PMID:22915801

Understanding deformation mechanisms during powder compaction using principal component analysis of compression data.

PubMed

Roopwani, Rahul; Buckner, Ira S

2011-10-14

Principal component analysis (PCA) was applied to pharmaceutical powder compaction. A solid fraction parameter (SF(c/d)) and a mechanical work parameter (W(c/d)) representing irreversible compression behavior were determined as functions of applied load. Multivariate analysis of the compression data was carried out using PCA. The first principal component (PC1) showed loadings for the solid fraction and work values that agreed with changes in the relative significance of plastic deformation to consolidation at different pressures. The PC1 scores showed the same rank order as the relative plasticity ranking derived from the literature for common pharmaceutical materials. The utility of PC1 in understanding deformation was extended to binary mixtures using a subset of the original materials. Combinations of brittle and plastic materials were characterized using the PCA method. The relationships between PC1 scores and the weight fractions of the mixtures were typically linear showing ideal mixing in their deformation behaviors. The mixture consisting of two plastic materials was the only combination to show a consistent positive deviation from ideality. The application of PCA to solid fraction and mechanical work data appears to be an effective means of predicting deformation behavior during compaction of simple powder mixtures. Copyright © 2011 Elsevier B.V. All rights reserved.

Focusing light in a bianisotropic slab with negatively refracting materials.

PubMed

Liu, Yan; Guenneau, Sebastien; Gralak, Boris; Ramakrishna, S Anantha

2013-04-03

We investigate the electromagnetic response of a pair of complementary bianisotropic media, which consist of a medium with positive refractive index (+ε, +μ, +ξ) and a medium with negative refractive index(-ε, -μ, -ξ). We show that this idealized system has peculiar imaging properties in that it reproduces images of a source, in principle, with unlimited resolution. We then consider an infinite array of line sources regularly spaced in a 1D photonic crystal (PC) consisting of 2n layers of bianisotropic complementary media. Using coordinate transformations, we map this system into 2D corner chiral lenses of 2n heterogeneous anisotropic complementary media sharing a vertex, within which light circles around closed trajectories. Alternatively, one can consider corner lenses with homogeneous isotropic media and map them into 1D PCs with heterogeneous bianisotropic layers. Interestingly, such complementary media are described by scalar, or matrix valued, sign-shifting parameters, which satisfy a new version of the generalized lens theorem of Pendry and Ramakrishna. This theorem can be derived using Fourier series solutions of the Maxwell-Tellegen equations, or from space-time symmetry arguments. Also of interest are 2D periodic checkerboards consisting of alternating rectangular cells of complementary media which are such that one point source in one cell gives rise to an infinite set of images with an image in every other cell. Such checkerboards can themselves be mapped into a class of 3D corner lenses of complementary bianisotropic media. These theoretical results are illustrated by finite element computations.

Experimental study on the dynamic mechanical behaviors of polycarbonate

NASA Astrophysics Data System (ADS)

Zhang, Wei; Gao, Yubo; Cai, Xuanming; Ye, Nan; Huang, Wei; Hypervelocity Impact Research Center Team

2015-06-01

Polycarbonate (PC) is a widely used engineering material in aerospace field, since it has excellent mechanical and optical property. In present study, both compress and tensile tests of PC were conducted at high strain rates by using a split Hopkinson pressure bar. The high-speed camera and 2D digital speckle correlation method (DIC) were used to analyze the dynamic deformation behavior of PC. Meanwhile, the plate impact experiment was carried out to measure the equation of state of PC in a single-stage gas gun, which consists of asymmetric impact technology, manganin gauges, PVDF, electromagnetic particle velocity gauges. The results indicate that the yield stress of PC increased with the strain rates. The strain softening occurred when the stress over yield point except the tensile tests in the strain rates of 1076s-1 and 1279s-1. The ZWT model can describe the constitutive behaviors of PC accurately in different strain rates by contrast with the results of 2D-DIC. At last, The D-u Hugoniot curve of polycarbonate in high pressure was fitted by the least square method. And the final results showed more closely to Cater and Mash than other previous data.

Identification and characterization of two arasin-like peptides in red swamp crayfish Procambarus clarkii.

PubMed

Chai, Lian-Qin; Li, Wan-Wan; Wang, Xian-Wei

2017-11-01

Antimicrobial peptides (AMPs) are small effectors in host defense by directly targeting microorganisms or by indirectly modulating immune responses. In the present study, two arasin like AMPs, named as Pc-arasin1 and Pc-arasin2, were identified in red swamp crayfish Procambarus clarkii with sequence similarity to the arasins found in Hyas araneus. Both Pc-arasins consisted of signal peptide, N-terminal proline-rich region and C-terminal region containing four conserved cysteine residues. The similarity of two Pc-arasins was 44.44%, and Pc-arasin2 contained several additional residues in the N-terminus. Multiple alignment of arasin family suggested the conservation of the C-terminus and the variation of the N-terminus of Pc-arasins. Both AMPs were found hemocytes-specific, and the expression could be induced the challenge of bacteria, espeacially by the pathogenic bacterium Aeromonas hydrophila. Knockdown of each Pc-arasin expression by double strand RNA would suppress the host immunity against A. hydrophila, and the commercially synthetic Pc-arasins could rescue the knockdown consequence. Both synthetic peptide showed broad antimicrobial activity towards 3 Gram-positive bacterium and 3 Gram-negative bacterium, and the minimal inhibitory concentrations varied from 6.25 μM to 50 μM. These results presented new data about the sequence, expression and function of arasin family, and emphasized the role of this family in host immune response against bacterial pathogens. The characterization of Pc-arasins also provided potential of therapeutic agent development for disease control in aquaculture based on these two newly identified AMPs. Copyright © 2017 Elsevier Ltd. All rights reserved.

Analysis of environmental variation in a Great Plains reservoir using principal components analysis and geographic information systems

USGS Publications Warehouse

Long, J.M.; Fisher, W.L.

2006-01-01

We present a method for spatial interpretation of environmental variation in a reservoir that integrates principal components analysis (PCA) of environmental data with geographic information systems (GIS). To illustrate our method, we used data from a Great Plains reservoir (Skiatook Lake, Oklahoma) with longitudinal variation in physicochemical conditions. We measured 18 physicochemical features, mapped them using GIS, and then calculated and interpreted four principal components. Principal component 1 (PC1) was readily interpreted as longitudinal variation in water chemistry, but the other principal components (PC2-4) were difficult to interpret. Site scores for PC1-4 were calculated in GIS by summing weighted overlays of the 18 measured environmental variables, with the factor loadings from the PCA as the weights. PC1-4 were then ordered into a landscape hierarchy, an emergent property of this technique, which enabled their interpretation. PC1 was interpreted as a reservoir scale change in water chemistry, PC2 was a microhabitat variable of rip-rap substrate, PC3 identified coves/embayments and PC4 consisted of shoreline microhabitats related to slope. The use of GIS improved our ability to interpret the more obscure principal components (PC2-4), which made the spatial variability of the reservoir environment more apparent. This method is applicable to a variety of aquatic systems, can be accomplished using commercially available software programs, and allows for improved interpretation of the geographic environmental variability of a system compared to using typical PCA plots. ?? Copyright by the North American Lake Management Society 2006.

Internal high-reflectivity omni-directional reflectors

NASA Astrophysics Data System (ADS)

Xi, J.-Q.; Ojha, Manas; Plawsky, J. L.; Gill, W. N.; Kim, Jong Kyu; Schubert, E. F.

2005-07-01

An internal high-reflectivity omni-directional reflector (ODR) for the visible spectrum is realized by the combination of total internal reflection using a low-refractive-index (low-n) material and reflection from a one-dimensional photonic crystal (1D PC). The low-n layer limits the range of angles in the 1D PC to values below the Brewster angle, thereby enabling high reflectivity and omni-directionality. This ODR is demonstrated using GaP as ambient, nanoporous SiO2 with a very low refractive index (n=1.10), and a four-pair TiO2/SiO2 multilayer stack. The results indicate a two orders of magnitude lower angle-integrated transverse-electric-transverse-magnetic polarization averaged mirror loss of the ODR compared with conventional distributed Bragg reflectors and metal reflectors. This indicates the high potential of the internal ODRs for optoelectronic semiconductor devices, e.g., light-emitting diodes.

Nanoantenna-Microcavity Hybrids with Highly Cooperative Plasmonic-Photonic Coupling

NASA Astrophysics Data System (ADS)

Liu, Jui-Nung; Huang, Qinglan; Liu, Keng-Ku; Singamaneni, Srikanth; Cunningham, Brian T.

2017-12-01

Nanoantennas concentrate electromagnetic energy into deep-subwavelength volumes (hotspot), which benefits a wide range of applications such as spontaneous emission enhancement, nonlinear optics, nanolaser, and surface-enhanced Raman scattering (SERS). To increase hotspot intensity, methods for sculpting individual nanoantenna resonance have been previously explored. Here, we study a nanoantenna-microcavity hybrid approach for highly cooperative hotspot enhancement, combining gold nanorods (AuNRs) for nanometer-scale light concentration and a resonant photonic crystal (PC) slab for efficient near-field excitation and optical feedback. We experimentally validate the predicted synergistic hybrid enhancement with SERS, and demonstrate that coupling to the modest-Q PC guided resonance (PCGR) boosts the hotspot intensity of the AuNR by at least one order of magnitude in comparison to the Fabry-Perot cavity enhanced (~5X) AuNR. These results exhibit a dissimilar hybrid cooperativity versus previously reported nanoantenna-cavity systems, and pave the new way to further facilitate light-nanoantenna interaction for many applications.

Nanocrystal waveguide (NOW) laser

DOEpatents

Simpson, John T.; Simpson, Marcus L.; Withrow, Stephen P.; White, Clark W.; Jaiswal, Supriya L.

2005-02-08

A solid state laser includes an optical waveguide and a laser cavity including at least one subwavelength mirror disposed in or on the optical waveguide. A plurality of photoluminescent nanocrystals are disposed in the laser cavity. The reflective subwavelength mirror can be a pair of subwavelength resonant gratings (SWG), a pair of photonic crystal structures (PC), or a distributed feedback structure. In the case of a pair of mirrors, a PC which is substantially transmissive at an operating wavelength of the laser can be disposed in the laser cavity between the subwavelength mirrors to improve the mode structure, coherence and overall efficiency of the laser. A method for forming a solid state laser includes the steps of providing an optical waveguide, creating a laser cavity in the optical waveguide by disposing at least one subwavelength mirror on or in the waveguide, and positioning a plurality of photoluminescent nanocrystals in the laser cavity.

A Tool for Medical Research

NASA Technical Reports Server (NTRS)

1992-01-01

California Measurements, Inc.'s PC-2 Aerosol Particle Analyzer, developed by William Chiang, a former Jet Propulsion Laboratory (JPL) engineer, was used in a study to measure the size of particles in the medical environment. Chiang has a NASA license for the JPL crystal oscillator technology and originally built the instrument for atmospheric research. In the operating room, it enabled researchers from the University of California to obtain multiple sets of data repeatedly and accurately. The study concluded that significant amounts of aerosols are generated during surgery when power tools are employed, and most of these are in the respirable size. Almost all contain blood and are small enough to pass through surgical masks. Research on the presence of blood aerosols during oral surgery had similar results. Further studies are planned to determine the possibility of HIV transmission during surgery, and the PC-2H will be used to quantify blood aerosols.

High-performance polymer/layered silicate nanocomposites

NASA Astrophysics Data System (ADS)

Heidecker, Matthew J.

High-performance layered-silicate nanocomposites of Polycarbonate (PC), poly(ethylene terephthalate) (PET), and their blends were produced via conventional melt-blending techniques. The focus of this thesis was on the fundamentals of dispersion, control of thermal stability, maintenance of melt-blending processing conditions, and on optimization of the composites' mechanical properties via the design of controlled and thermodynamically favorable nano-filler dispersions within the polymer matrices. PET and PC require high temperatures for melt-processing, rendering impractical the use of conventional/commercial organically-modified layered-silicates, since the thermal degradation temperatures of their ammonium surfactants lies below the typical processing temperatures. Thus, different surfactant chemistries must be employed in order to develop melt-processable nanocomposites, also accounting for polymer matrix degradation due to water (PET) or amine compounds (PC). Novel high thermal-stability surfactants were developed and employed in montmorillonite nanocomposites of PET, PC, and PC/PET blends, and were compared to the respective nanocomposites based on conventional quaternary-ammonium modified montmorillonites. Favorable dispersion was achieved in all cases, however, the overall material behavior -- i.e., the combination of crystallization, mechanical properties, and thermal degradation -- was better for the nanocomposites based on the thermally-stable surfactant fillers. Studies were also done to trace, and ultimately limit, the matrix degradation of Polycarbonate/montmorillonite nanocomposites, through varying the montmorillonite surfactant chemistry, processing conditions, and processing additives. Molecular weight degradation was, maybe surprisingly, better controlled in the conventional quaternary ammonium based nanocomposites -- even though the thermal stability of the organically modified montmorillonites was in most cases the lowest. Dependence of the resultant nanocomposites' mechanical properties on the preferential alignment of the montmorillonite nano-platelet was also evaluated. Highly aligned filler platelets did not result in an additional enhancement in mechanical properties. PC/PET blends and their respective PC/PET/montmorillonite nanocomposites were synthesized and compared. The dispersion of the organically modified nano-fillers in the PC/PET blends was controlled via thermodynamic considerations, realized through proper surfactant choice: Nanocomposites in which the layered silicate was preferentially sequestered in the PET phase were designed and synthesized. This preferential dispersion of the nano-filler in the PET phase of the PC/PET blend was insensitive to processing conditions, including approaches employing a master-batch (filler concentrate); regardless of the master-batch matrix, both PC and PET were employed, thermodynamics drove the layered silicate to preferentially migrate to the PET phase of the PC/PET blend. In a second approach, the development of a nanocomposite with controlled PC/PET compatibilization near the montmorillonite platelets, in absence of appreciable transesterification reactions, led to the formation of very high performance nanocomposites. These latter systems, point to an exciting new avenue of future considerations for nanocomposite blends with selective nano-filler dispersions, where performance can be tailored via the controlled preferential dispersion of nano-fillers in one phase, or by filler-induced polymer compatibilization.

[GSTP1, APC and RASSF1 gene methylation in prostate cancer samples: comparative analysis of MS-HRM method and Infinium HumanMethylation450 BeadChip beadchiparray diagnostic value].

PubMed

Skorodumova, L O; Babalyan, K A; Sultanov, R; Vasiliev, A O; Govorov, A V; Pushkar, D Y; Prilepskaya, E A; Danilenko, S A; Generozov, E V; Larin, A K; Kostryukova, E S; Sharova, E I

2016-11-01

There is a clear need in molecular markers for prostate cancer (PC) risk stratification. Alteration of DNA methylation is one of processes that occur during ÐÑ progression. Methylation-sensitive PCR with high resolution melting curve analysis (MS-HRM) can be used for gene methylation analysis in routine laboratory practice. This method requires very small amounts of DNA for analysis. Numerous results have been accumulated on DNA methylation in PC samples analyzed by the Infinium HumanMethylation450 BeadChip (HM450). However, the consistency of MS-HRM results with chip hybridization results has not been examined yet. The aim of this study was to assess the consistency of results of GSTP1, APC and RASSF1 gene methylation analysis in ÐÑ biopsy samples obtained by MS-HRM and chip hybridization. The methylation levels of each gene determined by MS-HRM were statistically different in the group of PC tissue samples and the samples without signs of tumor growth. Chip hybridization data analysis confirmed the results obtained with the MS-HRM. Differences in methylation levels between tumor tissue and histologically intact tissue of each sample determined by MS-HRM and chip hybridization, were consistent with each other. Thus, we showed that the assessment of GSTP1, APC and RASSF1 gene methylation analysis using MS-HRM is suitable for the design of laboratory assays that will differentiate the PC tissue from the tissue without signs of tumor growth.

Nanostructured Surfaces and Detection Instrumentation for Photonic Crystal Enhanced Fluorescence

PubMed Central

Chaudhery, Vikram; George, Sherine; Lu, Meng; Pokhriyal, Anusha; Cunningham, Brian T.

2013-01-01

Photonic crystal (PC) surfaces have been demonstrated as a compelling platform for improving the sensitivity of surface-based fluorescent assays used in disease diagnostics and life science research. PCs can be engineered to support optical resonances at specific wavelengths at which strong electromagnetic fields are utilized to enhance the intensity of surface-bound fluorophore excitation. Meanwhile, the leaky resonant modes of PCs can be used to direct emitted photons within a narrow range of angles for more efficient collection by a fluorescence detection system. The multiplicative effects of enhanced excitation combined with enhanced photon extraction combine to provide improved signal-to-noise ratios for detection of fluorescent emitters, which in turn can be used to reduce the limits of detection of low concentration analytes, such as disease biomarker proteins. Fabrication of PCs using inexpensive manufacturing methods and materials that include replica molding on plastic, nano-imprint lithography on quartz substrates result in devices that are practical for single-use disposable applications. In this review, we will describe the motivation for implementing high-sensitivity fluorescence detection in the context of molecular diagnosis and gene expression analysis though the use of PC surfaces. Recent efforts to improve the design and fabrication of PCs and their associated detection instrumentation are summarized, including the use of PCs coupled with Fabry-Perot cavities and external cavity lasers. PMID:23624689

Crystal structure of bis-[(phenyl-methanamine-κN)(phthalocyaninato-κ(4) N)zinc] phenyl-methan-amine tris-olvate.

PubMed

Shamsudin, Norzianah; Tan, Ai Ling; Wimmer, Franz L; Young, David J; Tiekink, Edward R T

2015-09-01

The asymmetric unit of the title compound, 2[Zn(C32H16N8)(C7H9N)]·3C7H9N, comprises two independent complex mol-ecules and three benzyl-amine solvent mol-ecules. Each complex mol-ecule features a penta-coordinated Zn(2+) ion within a square-pyramidal geometry, whereby the N5 donor set is defined by four atoms of the phthalocyaninate dianion (PC) and an N-bound benzyl-amine mol-ecule; it is the relative orientations of the latter that differentiate between the independent complex mol-ecules. The uncoordinated benzyl-amine mol-ecules display different conformations in the structure, with syn-Car-Car-Cm-N (ar = aromatic, m = methyl-ene) torsion angles spanning the range -28.7 (10) to 35.1 (14)°. In the crystal, N-H⋯N and N-H⋯π inter-actions lead to supra-molecular layers in the ab plane. The layers have a zigzag topology, have the coordinating and non-coordinating benzyl-amine mol-ecules directed to the inside, and present the essentially flat PC resides to the outside. This arrangement enables adjacent layers to associate via π-π inter-actions [inter-centroid distance between pyrrolyl and fused-benzene rings = 3.593 (2) Å] so that a three-dimensional architecture is formed.

Exquisite Enzyme-Fenton Biomimetic Catalysts for Hydroxyl Radical Production by Mimicking an Enzyme Cascade.

PubMed

Zhang, Qi; Chen, Shuo; Wang, Hua; Yu, Hongtao

2018-03-14

Hydrogen peroxide (H 2 O 2 ) is a key reactant in the Fenton process. As a byproduct of enzymatic reaction, H 2 O 2 can be obtained via catalytical oxidation of glucose using glucose oxidase in the presence of O 2 . Another oxidation product (gluconic acid) can suitably adjust the microenvironmental pH contributing to the Fe 3+ /Fe 2+ cycle in the Fenton reaction. Enzymes are extremely efficient at catalyzing a variety of reactions with high catalytic activity, substrate specificity, and yields in living organisms. Inspired by the multiple functions of natural multienzyme systems, an exquisite nanozyme-modified α-FeOOH/porous carbon (PC) biomimetic catalyst constructed by in situ growth of glucose oxidase-mimicking Au nanoparticles and crystallization of adsorbed ferric ions within carboxyl into hierarchically PC is developed as an efficient enzyme-Fenton catalyst. The products (H 2 O 2 , ∼4.07 mmol·L -1 ) of the first enzymatic reaction are immediately used as substrates for the second Fenton-like reaction to generate the valuable • OH (∼96.84 μmol·L -1 ), thus mimicking an enzyme cascade pathway. α-FeOOH nanocrystals, attached by C-O-Fe bondings, are encapsulated into the mesoporous PC frameworks, facilitating the electron transfer between α-FeOOH and the PC support and greatly suppressing iron leaching. This study paves a new avenue for designing biomimetic enzyme-based Fenton catalysts mimicking a natural system for • OH production.

Stereoscopic-3D display design: a new paradigm with Intel Adaptive Stable Image Technology [IA-SIT

NASA Astrophysics Data System (ADS)

Jain, Sunil

2012-03-01

Stereoscopic-3D (S3D) proliferation on personal computers (PC) is mired by several technical and business challenges: a) viewing discomfort due to cross-talk amongst stereo images; b) high system cost; and c) restricted content availability. Users expect S3D visual quality to be better than, or at least equal to, what they are used to enjoying on 2D in terms of resolution, pixel density, color, and interactivity. Intel Adaptive Stable Image Technology (IA-SIT) is a foundational technology, successfully developed to resolve S3D system design challenges and deliver high quality 3D visualization at PC price points. Optimizations in display driver, panel timing firmware, backlight hardware, eyewear optical stack, and synch mechanism combined can help accomplish this goal. Agnostic to refresh rate, IA-SIT will scale with shrinking of display transistors and improvements in liquid crystal and LED materials. Industry could profusely benefit from the following calls to action:- 1) Adopt 'IA-SIT S3D Mode' in panel specs (via VESA) to help panel makers monetize S3D; 2) Adopt 'IA-SIT Eyewear Universal Optical Stack' and algorithm (via CEA) to help PC peripheral makers develop stylish glasses; 3) Adopt 'IA-SIT Real Time Profile' for sub-100uS latency control (via BT Sig) to extend BT into S3D; and 4) Adopt 'IA-SIT Architecture' for Monitors and TVs to monetize via PC attach.

Signal transduction in neurons: effects of cellular prion protein on fyn kinase and ERK1/2 kinase.

PubMed

Tomasi, Vittorio

2010-12-16

It has been reported that cellular prion protein (PrPc) co-localizes with caveolin-1 and participates to signal transduction events by recruiting Fyn kinase. As PrPc is a secreted protein anchored to the outer surface membrane through a glycosylphosphatidylinositol (GPI) anchor (secPrP) and caveolin-1 is located in the inner leaflet of plasma membrane, there is a problem of how the two proteins can physically interact each other and transduce signals. By using the GST-fusion proteins system we observed that PrPc strongly interacts with caveolin-1 scaffolding domain and with a caveolin-1 hydrophilic C-terminal region, but not with the caveolin-1 N-terminal region. In vitro binding experiments were also performed to define the site(s) of PrPc interacting with cav-1. The results are consistent with a participation of PrPc octapeptide repeats motif in the binding to caveolin-1 scaffolding domain. The caveolar localization of PrPc was ascertained by co-immunoprecipitation, by co-localization after flotation in density gradients and by confocal microscopy analysis of PrPc and caveolin-1 distributions in a neuronal cell line (GN11) expressing caveolin-1 at high levels. We observed that, after antibody-mediated cross-linking or copper treatment, PrPc was internalized probably into caveolae. We propose that following translocation from rafts to caveolae or caveolae-like domains, secPrP could interact with caveolin-1 and induce signal transduction events.

Conditional Deletion of Prnp Rescues Behavioral and Synaptic Deficits after Disease Onset in Transgenic Alzheimer's Disease

PubMed Central

Kaufman, Adam C.; Herber, Charlotte S.; Haas, Laura T.; Robinson, Sophie; Lee, Michael K.

2017-01-01

Biochemical and genetic evidence implicate soluble oligomeric amyloid-β (Aβo) in triggering Alzheimer's disease (AD) pathophysiology. Moreover, constitutive deletion of the Aβo-binding cellular prion protein (PrPC) prevents development of memory deficits in APPswe/PS1ΔE9 mice, a model of familial AD. Here, we define the role of PrPC to rescue or halt established AD endophenotypes in a therapeutic disease-modifying time window after symptom onset. Deletion of Prnp at either 12 or 16 months of age fully reverses hippocampal synapse loss and completely rescues preexisting behavioral deficits by 17 months. In contrast, but consistent with a neuronal function for Aβo/PrPC signaling, plaque density, microgliosis, and astrocytosis are not altered. Degeneration of catecholaminergic neurons remains unchanged by PrPC reduction after disease onset. These results define the potential of targeting PrPC as a disease-modifying therapy for certain AD-related phenotypes after disease onset. SIGNIFICANCE STATEMENT The study presented here further elucidates our understanding of the soluble oligomeric amyloid-β–Aβo-binding cellular prion protein (PrPC) signaling pathway in a familial form of Alzheimer's disease (AD) by implicating PrPC as a potential therapeutic target for AD. In particular, genetic deletion of Prnp rescued several familial AD (FAD)-associated phenotypes after disease onset in a mouse model of FAD. This study underscores the therapeutic potential of PrPC deletion given that patients already present symptoms at the time of diagnosis. PMID:28842420

Effect of biotin on activity and gene expression of biotin-dependent carboxylases in the liver of dairy cows.

PubMed

Ferreira, G; Weiss, W P

2007-03-01

Biotin is a cofactor of the gluconeogenic enzymes pyruvate carboxylase (PC) and propionyl-coenzyme A carboxylase (PCC). We hypothesized that biotin supplementation increases the activity and gene expression of PC and PCC and the gene expression of phosphoenol-pyruvate carboxykinase (PEPCK) in the liver of lactating dairy cows. Eight multiparous Holstein cows (40 +/- 2 kg/d of milk yield and 162 +/- 35 d in milk) were randomly assigned to 1 of 2 diet sequences in a crossover design with two 22-d periods. Treatments consisted of a basal diet (60% concentrate) containing 0 or 0.96 mg/kg of supplemental biotin. On d 21 of each period, liver tissue was collected by percutaneous liver biopsy. Activities of PC and PCC were determined by measuring the fixation of [14C]O2 in liver homogenates. Abundance of mRNA for PCC, PC, and PEPCK was determined by quantitative reverse-transcription PCR. Biotin supplementation did not affect milk production or composition. Biotin supplementation increased the activity of PC but had no effect on PCC activity. Biotin supplementation did not affect the gene expression of PC, PCC, and PEPCK. The increased activity of PC without changes in mRNA abundance may have been caused by increased activation of the apoenzymes by holocarboxylase synthetase. In conclusion, biotin supplementation affected the activity of PC in the liver of lactating dairy cows, but whether biotin supplementation increases glucose production in the liver remains to be determined.

PC-based note taking in patient-centred diagnostic interviews: a thematic analysis of patient opinion elicited using a pilot survey instrument.

PubMed

Barker, Fiona; Court, Gemma

2011-01-01

Computers are used increasingly in patient-clinician consultations. There is the potential for PC use to have an effect on the communication process. The aim of this preliminary study was to investigate patient opinion regarding the use of PC-based note taking during diagnostic vestibular assessments. We gave a simple four-item questionnaire to 100 consecutive patients attending for vestibular assessment at a secondary referral level primary care trust audiology service. Written responses to two of the questionnaire items were subject to an inductive thematic analysis. The questionnaire was acceptable to patients, none refused to complete it. Dominant themes identified suggest that patients do perceive consistent positive benefits from the use of PC-based note taking. This pilot study's short survey instrument is usable and may provide insights into patients' perceptions of computer use in a clinical setting.

Optically thin hybrid cavity for terahertz photo-conductive detectors

DOE PAGES

Thompson, Robert J.; Siday, T.; Glass, S.; ...

2017-01-23

Here, the efficiency of photoconductive (PC) devices, including terahertz detectors, is constrained by the bulk optical constants of PC materials. Here, we show that optical absorption in a PC layer can be modified substantially within a hybrid cavity containing nanoantennas and a Distributed Bragg Reflector. We find that a hybrid cavity, consisting of a GaAs PC layer of just 50 nm, can be used to absorb >75% of incident photons by trapping the light within the cavity. We provide an intuitive model, which describes the dependence of the optimum operation wavelength on the cavity thickness. We also find that themore » nanoantenna size is a critical parameter, small variations of which lead to both wavelength shifting and reduced absorption in the cavity, suggesting that impedance matching is key for achieving efficient absorption in the optically thin hybrid cavities.« less

Internal structure of copper(II)-phthalocyanine thin films on SiO2/Si substrates investigated by grazing incidence x-ray reflectometry

NASA Astrophysics Data System (ADS)

Brieva, A. C.; Jenkins, T. E.; Jones, D. G.; Strössner, F.; Evans, D. A.; Clark, G. F.

2006-04-01

The internal structure of copper(II)-phthalocyanine (CuPc) thin films grown on SiO2/Si by organic molecular beam deposition has been studied by grazing incidence x-ray reflectometry (GIXR) and atomic force microscopy. The electronic density profile is consistent with a structure formed by successive monolayers of molecules in the α form with the b axis lying in the substrate surface plane. The authors present an electronic density profile model of CuPc films grown on SiO2/Si. The excellent agreement between the model and experimental data allows postdeposition monitoring of the internal structure of the CuPc films with the nondestructive GIXR technique, providing a tool for accurate control of CuPc growth on silicon-based substrates. In addition, since the experiments have been carried out ex situ, they show that these structures can endure ambient conditions.

Nanoimprinting-induced nanomorphological transition in polymer solar cells: enhanced electrical and optical performance.

PubMed

Jeong, Seonju; Cho, Changsoon; Kang, Hyunbum; Kim, Ki-Hyun; Yuk, Youngji; Park, Jeong Young; Kim, Bumjoon J; Lee, Jung-Yong

2015-03-24

We have investigated the effects of a directly nanopatterned active layer on the electrical and optical properties of inverted polymer solar cells (i-PSCs). The capillary force in confined molds plays a critical role in polymer crystallization and phase separation of the film. The nanoimprinting process induced improved crystallization and multidimensional chain alignment of polymers for more effective charge transfer and a fine phase-separation between polymers and [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) to favor exciton dissociation and increase the generation rate of charge transfer excitons. Consequently, the power conversion efficiency with a periodic nanostructure was enhanced from 7.40% to 8.50% and 7.17% to 9.15% in PTB7 and PTB7-Th based i-PSCs, respectively.

A scalable PC-based parallel computer for lattice QCD

NASA Astrophysics Data System (ADS)

Fodor, Z.; Katz, S. D.; Pappa, G.

2003-05-01

A PC-based parallel computer for medium/large scale lattice QCD simulations is suggested. The Eo¨tvo¨s Univ., Inst. Theor. Phys. cluster consists of 137 Intel P4-1.7GHz nodes. Gigabit Ethernet cards are used for nearest neighbor communication in a two-dimensional mesh. The sustained performance for dynamical staggered (wilson) quarks on large lattices is around 70(110) GFlops. The exceptional price/performance ratio is below $1/Mflop.

Ghrelin inhibits proliferation and increases T-type Ca{sup 2+} channel expression in PC-3 human prostate carcinoma cells

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

Diaz-Lezama, Nundehui; Hernandez-Elvira, Mariana; Sandoval, Alejandro

Research highlights: {yields} Ghrelin decreases prostate carcinoma PC-3 cells proliferation. {yields} Ghrelin favors apoptosis in PC-3 cells. {yields} Ghrelin increase in intracellular free Ca{sup 2+} levels in PC-3 cells. {yields} Grelin up-regulates expression of T-type Ca{sup 2+} channels in PC-3 cells. {yields} PC-3 cells express T-channels of the Ca{sub V}3.1 and Ca{sub V}3.2 subtype. -- Abstract: Ghrelin is a multifunctional peptide hormone with roles in growth hormone release, food intake and cell proliferation. With ghrelin now recognized as important in neoplastic processes, the aim of this report is to present findings from a series of in vitro studies evaluating themore » cellular mechanisms involved in ghrelin regulation of proliferation in the PC-3 human prostate carcinoma cells. The results showed that ghrelin significantly decreased proliferation and induced apoptosis. Consistent with a role in apoptosis, an increase in intracellular free Ca{sup 2+} levels was observed in the ghrelin-treated cells, which was accompanied by up-regulated expression of T-type voltage-gated Ca{sup 2+} channels. Interestingly, T-channel antagonists were able to prevent the effects of ghrelin on cell proliferation. These results suggest that ghrelin inhibits proliferation and may promote apoptosis by regulating T-type Ca{sup 2+} channel expression.« less

Realizing broad-bandwidth visible wavelength photodiode based on solution-processed ZnPc/PC71BM dyad

NASA Astrophysics Data System (ADS)

Zafar, Qayyum; Fatima, Noshin; Karimov, Khasan S.; Ahmed, Muhammad M.; Sulaiman, Khaulah

2017-02-01

Herein, we demonstrate a solution-processed visible wavelength organic photodiode (OPD) using donor/acceptor dyad of zinc phthalocyanine (ZnPc) and [6,6]-phenyl-C71-butyric-acid methyl ester (PC71BM), respectively. The synergic absorption profiles of both ZnPc and PC71BM moieties have been exploited to realize broader (350 and 800 nm) and consistent absorption spectrum of the photoactive film. The optimum loading ratio (by volume) of D/A dyad has been estimated to be 1:0.8, via quenching phenomenon in ZnPc photoluminescence spectrum. The performance of the OPD has been evaluated by detecting the photocurrent density with respect to varied illumination levels (0-150 mW/cm2) of impinging light at different reverse bias conditions. Under identical reverse bias mode, the photocurrent density has shown significant upsurge as the incident intensity of light is increased; ultimately leading to the significantly higher responsivity (162.4 μA/W) of the fabricated diode. The light to dark current density ratio (Jph/Jd) of the device at 3 V reverse bias has been calculated to be ∼20.12. The transient photocurrent density response of the fabricated OPD has also been characterized at -4 V operational bias under switch ON/OFF illumination. The measured response and recovery time for the fabricated OPD are ∼200 and 300 ms, respectively.

Defeating Leishmania resistance to miltefosine (hexadecylphosphocholine) by peptide-mediated drug smuggling: a proof of mechanism for trypanosomatid chemotherapy.

PubMed

Luque-Ortega, Juan Román; de la Torre, Beatriz G; Hornillos, Valentín; Bart, Jean-Mathieu; Rueda, Cristina; Navarro, Miguel; Amat-Guerri, Francisco; Acuña, A Ulises; Andreu, David; Rivas, Luis

2012-08-10

Miltefosine (hexadecylphosphocholine, HePC), the first orally active drug successful against leishmaniasis, is especially active on the visceral form of the disease. Resistance mechanisms are almost exclusively associated to dysfunction in HePC uptake systems. In order to evade the requirements of its cognate receptor/translocator, HePC-resistant Leishmania donovani parasites (R40 strain) were challenged with constructs consisting of an ω-thiol-functionalized HePC analogue conjugated to the cell-penetrating peptide (CPP) Tat(48-60), either through a disulfide or a thioether bond. The conjugates enter and kill both promastigote and intracellular amastigote forms of the R40 strain. Intracellular release of HePC by reduction of the disulfide-based conjugate was confirmed by means of double tagging at both the CPP (Quasar 670) and HePC (BODIPY) moieties. Scission of the conjugate, however, is not mandatory, as the metabolically more stable thioether conjugate retained substantial activity. The disulfide conjugate is highly active on the bloodstream form of Trypanosoma b. brucei, naturally resistant to HePC. Our results provide proof-of-mechanism for the use of CPP conjugates to avert drug resistance by faulty drug accumulation in parasites, as well as the possibility to extend chemotherapy into other parasites intrinsically devoid of membrane translocation systems. Copyright © 2012 Elsevier B.V. All rights reserved.

Conformational Sampling and Binding Site Assessment of Suppression of Tumorigenicity 2 Ectodomain

PubMed Central

Yang, Chao-Yie; Delproposto, James; Chinnaswamy, Krishnapriya; Brown, William Clay; Wang, Shuying; Stuckey, Jeanne A.; Wang, Xinquan

2016-01-01

Suppression of Tumorigenicity 2 (ST2), a member of the interleukin-1 receptor (IL-1R) family, activates type 2 immune responses to pathogens and tissue damage via binding to IL-33. Dysregulated responses contribute to asthma, graft-versus-host and autoinflammatory diseases and disorders. To study ST2 structure for inhibitor development, we performed the principal component (PC) analysis on the crystal structures of IL1-1R1, IL1-1R2, ST2 and the refined ST2 ectodomain (ST2ECD) models, constructed from previously reported small-angle X-ray scattering data. The analysis facilitates mapping of the ST2ECD conformations to PC subspace for characterizing structural changes. Extensive coverage of ST2ECD conformations was then obtained using the accelerated molecular dynamics simulations started with the IL-33 bound ST2ECD structure as instructed by their projected locations on the PC subspace. Cluster analysis of all conformations further determined representative conformations of ST2ECD ensemble in solution. Alignment of the representative conformations with the ST2/IL-33 structure showed that the D3 domain of ST2ECD (containing D1-D3 domains) in most conformations exhibits no clashes with IL-33 in the crystal structure. Our experimental binding data informed that the D1-D2 domain of ST2ECD contributes predominantly to the interaction between ST2ECD and IL-33 underscoring the importance of the D1-D2 domain in binding. Computational binding site assessment revealed one third of the total detected binding sites in the representative conformations may be suitable for binding to potent small molecules. Locations of these sites include the D1-D2 domain ST2ECD and modulation sites conformed to ST2ECD conformations. Our study provides structural models and analyses of ST2ECD that could be useful for inhibitor discovery. PMID:26735493

PrPC expression and prion seeding activity in the alimentary tract and lymphoid tissue of deer

PubMed Central

Davenport, Kristen A.; Hoover, Clare E.; Bian, Jifeng; Telling, Glenn C.; Mathiason, Candace K.; Hoover, Edward A.

2017-01-01

The agent responsible for prion diseases is a misfolded form of a normal protein (PrPC). The prion hypothesis stipulates that PrPC must be present for the disease to manifest. Cervid populations across the world are infected with chronic wasting disease, a horizontally-transmissible prion disease that is likely spread via oral exposure to infectious prions (PrPCWD). Though PrPCWD has been identified in many tissues, there has been little effort to characterize the overall PrPC expression in cervids and its relationship to PrPCWD accumulation. We used immunohistochemistry (IHC), western blot and enzyme-linked immunosorbent assay to describe PrPC expression in naïve white-tailed deer. We used real-time, quaking-induced conversion (RT-QuIC) to detect prion seeding activity in CWD-infected deer. We assessed tissues comprising the alimentary tract, alimentary-associated lymphoid tissue and systemic lymphoid tissue from 5 naïve deer. PrPC was expressed in all tissues, though expression was often very low compared to the level in the CNS. IHC identified specific cell types wherein PrPC expression is very high. To compare the distribution of PrPC to PrPCWD, we examined 5 deer with advanced CWD infection. Using RT-QuIC, we detected prion seeding activity in all 21 tissues. In 3 subclinical deer sacrificed 4 months post-inoculation, we detected PrPCWD consistently in alimentary-associated lymphoid tissue, irregularly in alimentary tract tissues, and not at all in the brain. Contrary to our hypothesis that PrPC levels dictate prion accumulation, PrPC expression was higher in the lower gastrointestinal tissues than in the alimentary-associated lymphoid system and was higher in salivary glands than in the oropharyngeal lymphoid tissue. These data suggest that PrPC expression is not the sole driver of prion accumulation and that alimentary tract tissues accumulate prions before centrifugal spread from the brain occurs. PMID:28880938

Chemical and Topographical Modification of Polycarbonate Surfaces through Diffusion/Photocuring Processes of Hydrogel Precursors Based on Vinylpyrrolidone.

PubMed

Gallardo, Alberto; Lujan, Noelia; Reinecke, Helmut; García, Carolina; Campo, Adolfo Del; Rodriguez-Hernandez, Juan

2017-02-21

Facile procedures capable of simultaneously conferring hydrophilicity and tailored topography to surfaces of hydrophobic supports, such as polycarbonate (PC), are very attractive but rare. In this work, we describe a simple methodology to wrinkle PC surfaces after a process of (a) contacting with a photopolymerizable vinylic solution, (b) UV curing of such solutions, and (c) detachment of the formed polymer network, upon swelling in ethanol. The influence of different parameters such as contact lag time between the PC surface and the polymerizable solution, the monomer concentration and type of solvents, as well as the cross-linking degree on the formation of wrinkles, has been studied. The dimensions of the wrinkles can be tailored to some extent by altering the different parameters. Surface chemistry has been analyzed by contact angle measurements and by confocal Raman microscopy. The results are consistent with a chemical alteration of the surface and the formation of an outer hydrogel layer, which is interpenetrated into the PC structure. A mechanism of monomer diffusion and PC swelling that produces surface instabilities and wrinkling is proposed.

Accumulation of phosphatidylcholine on gut mucosal surface is not dominated by electrostatic interactions.

PubMed

Korytowski, Agatha; Abuillan, Wasim; Amadei, Federico; Makky, Ali; Gumiero, Andrea; Sinning, Irmgard; Gauss, Annika; Stremmel, Wolfgang; Tanaka, Motomu

2017-05-01

The accumulation of phosphatidylcholine (PC) in the intestinal mucus layer is crucial for the protection of colon epithelia from the bacterial attack. It has been reported that the depletion of PC is a distinct feature of ulcerative colitis. Here we addressed the question how PC interacts with its binding proteins, the mucins, which may establish the hydrophobic barrier against colonic microbiota. In the first step, the interactions of dioleoylphosphatidylcholine (DOPC) with two mucin preparations from porcine stomach, have been studied using dynamic light scattering, zeta potential measurement, and Langmuir isotherms, suggesting that mucin binds to the surface of DOPC vesicles. The enthalpy of mucin-PC interaction could be determined by isothermal titration calorimetry. The high affinity to PC found for both mucin types seems reasonable, as they mainly consist of mucin 2, a major constituent of the flowing mucus. Moreover, by the systematic variation of net charges, we concluded that the zwitterionic DOPC has the strongest binding affinity that cannot be explained within the electrostatic interactions between charged molecules. Copyright © 2017 Elsevier B.V. All rights reserved.

Where are the Fermi lines coming from?

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

Rao, Kanishka; Whiteson, Daniel, E-mail: krao@uci.edu, E-mail: daniel@uci.edu

2013-03-01

We estimate the spatial locations of sources of the the observed features in the Fermi-LAT photon spectrum at E{sub γ} = 110 and E{sub γ} = 130 GeV. We determine whether they are consistent with emission from a single source, as would be expected in their interpretation as γγ and γZ lines from dark matter annhiliation, as well as whether they are consistent with a dark matter halo positioned at the center of the galaxy. We take advantage of the per-photon measured incident angle in reconstructing the line features. In addition, we use a data-driven background model rather than makingmore » the assumption of a feature-less background. We localize the sources of the features at 110 and 130 GeV. Assuming an Einasto (NFW) density model we find the 130 GeV line to be offset from the Galactic center by 285 (280) pc, the 110 GeV line by 60 (30) pc with a large relative separation of 220 (240) pc. However, we find this displacement of each source from the Galactic center, as well as their relative displacement to be statistically consistent with a single Einasto or NFW dark matter halo at the center of the galaxy.« less

Cathedral Peak Granodiorite, Sierra Nevada Batholith, California: A Big, Mushy, Magma System?

NASA Astrophysics Data System (ADS)

Burgess, S. D.; Miller, J. S.; Matzel, J. P.

2006-12-01

The Cathedral Peak Granodiorite (Kcp) is the largest mapped unit of the >1200 km2 Tuolumne Batholith (TB), which is one of a belt of Cretaceous zoned intrusions within the Sierra Nevada Batholith. Previous workers [1,2] proposed that the zonation in the TB was mainly produced in-situ either by inward differentiation of a large mass of magma and/or large-scale magma mixing between compositionally distinct map units. Recent geochronology has shown that the entire TB was intruded over 8-9 Ma, leading to the hypothesis that it was constructed continuously over this time period by many small increments [3], with variations in chemical and isotopic composition attributed to processes in the melt source. This hypothesis is also supported by scatter in trace elements vs. longitude from the margins to inner TB and appreciable variability in Nd and Sr isotopic data between the mapped units of the TB [e.g., 4]. Thus attributing chemical variations between major intrusive units to simple closed system fractionation or binary magma mixing is precluded. New field, geochemical and geochronologic work along a 5 km transect from the porphyritic Half Dome Granodiorite (Khdp) margin to the innermost Kcp, and approximately perpendicular to the Kcp-Khdp contact shows that: (1) magmatic foliation is moderately- to steeply-dipping (>60°); (2) zircon ages at each end of the transect are indistinguishable; (3) bulk composition varies only modestly but trace elements show variable degrees of scatter with greatest scatter observed among feldspar-compatible and highly incompatible elements (Sr, Ba, Th); (5) ɛNd(t) is invariant (Sr(i) has small variation); (6) abundant field evidence for transport and mixing of melt and crystals is observed (multiple generations of steep planar, tube- like, and chaotically folded schlieren, rafts and monomineralic clusters of K-feldspar, irregular and mingled contacts between sheets of texturally variable granite and schlieren). The broad geochemical and isotopic data are consistent with bulk fractionation in the Cathedral Peak Granodiorite. However, the geochemical spatial variation (especially trace elements) and field evidence suggest that fractionation was highly disorganized and involved mixing and remobilization of crystal mush as it solidified, possibly triggered by new inputs of isotopically uniform magma (i.e., recharge from the magma source). These data and observations are consistent with construction of a large, and dynamic but mushy magmatic system within the last 1 Ma of the total 9 Ma TB intrusion interval. [1] Bateman, PC & Chappell BW (1979) Geol Soc Am Bull, Part I 90:465-482; [2] Reid, JB, Evans, OC & Fates DG (1983) Earth Planet Sci Letters, 66:243-261; [3] Coleman, DS, Gray, W & Glazner, AF (2004) Geology, 32:433-436; [4] Kistler, RW, Chappell, BW, Peck, DL & Bateman, PC (1986) Contrib Min Pet, 94:205-220;

Electronic States in EuCu2(Ge1-xSix)2 Based on the Doniach Phase Diagram

NASA Astrophysics Data System (ADS)

Iha, Wataru; Yara, Tomoyuki; Ashitomi, Yousuke; Kakihana, Masashi; Takeuchi, Tetsuya; Honda, Fuminori; Nakamura, Ai; Aoki, Dai; Gouchi, Jun; Uwatoko, Yoshiya; Kida, Takanori; Tahara, Time; Hagiwara, Masayuki; Haga, Yoshinori; Hedo, Masato; Nakama, Takao; Ōnuki, Yoshichika

2018-06-01

We succeeded in growing single crystals of EuCu2(Ge1-xSix)2 (x = 0-1) by the Bridgman method using a Mo crucible and measured the electrical resistivity, specific heat, magnetic susceptibility, and magnetization, together with the electrical resistivity under pressure. EuCu2(Ge1-xSix)2 compounds follow the Doniach phase diagram as a function of the x content. Namely, EuCu2(Ge1-xSix)2 compounds exhibit antiferromagnetic ordering at a Néel temperature of TN = 15 K in EuCu2Ge2 (x = 0), a maximum of TN ≃ 20 K at x ≃ 0.5, TN → 0 at x ≃ 0.7, and a moderate heavy-fermion state at x = 0.8 and 1 (EuCu2Si2). The present result is reasonably consistent with the previous studies carried out using arc-melted polycrystal samples. A similar change in the electronic states was also found to be realized under pressure P for x = 0, 0.45, and 0.6. The Néel temperature of TN = 15 K for x = 0 (EuCu2Ge2) increases slightly as a function of pressure, at a rate of dTN/dP = 3.0 K/GPa, reaches a maximum of TN = 27 K at around 5-6 GPa, decreases steeply, and becomes zero at a critical pressure of Pc ≃ 7 GPa. A moderate heavy-fermion state is realized at 8 GPa. Similar results were also obtained for x = 0.45 and 0.6, with smaller critical pressures of Pc ≃ 4.5 and 2 GPa, respectively.

Room temperature, air crystallized perovskite film for high performance solar cells

DOE PAGES

Dubey, Ashish; Kantack, Nicholas; Adhikari, Nirmal; ...

2016-05-31

For the first time, room temperature heating free growth and crystallization of perovskite films in ambient air without the use of thermal annealing is reported. Highly efficient perovskite nanorod-based solar cells were made using ITO/PEDOT:PSS/CH 3NH 3PbI 3 nanorods/PC 60BM/rhodamine/Ag. All the layers except PEDOT:PSS were processed at room temperature thereby eliminating the need for thermal treatment. Perovskite films were spin coated inside a N-2 filled glovebox and immediately were taken outside in air having 40% relative humidity (RH). Exposure to humid air was observed to promote the crystallization process in perovskite films even at room temperature. Perovskite films keptmore » for 5 hours in ambient air showed nanorod-like morphology having high crystallinity, with devices exhibiting the highest PCE of 16.83%, which is much higher than the PCE of 11.94% for traditional thermally annealed perovskite film based devices. Finally, it was concluded that moisture plays an important role in room temperature crystallization of pure perovskite nanorods, showing improved optical and charge transport properties, which resulted in high performance solar cells.« less

[Emergency department as final destination: perception and reception of the palliative patient" concept as well as approach toward improving interdisciplinary collaboration - a survey of emergency personnel of a Swiss emergency department].

PubMed

Klenk, Laurence; Iucolano, Nicoletta M; Braun, Christian Tasso; Exadaktylos, Aristomenis K; Eychmüller, Steffen

2015-01-02

As the demand for palliative care (PC) in emergency wards continues to increase, emergency medicine is increasingly focusing on the care of extremely ill patients with incurable, chronic and/or advanced diseases. There is no consistent definition of the profile of PC or understanding of what PC involves. The mistake is often made of confusing PC with end-of-life or terminal care. The present study was intended to assess the situation at the Department of Emergency Medicine, Inselspital, Bern University Hospital (UNZ), which cares for about 32 400 patients annually. The plan was to find out how much staff members knew about PC and to survey their personal attitudes. The employees of the UNZ were surveyed with an online questionnaire by a special institution outside the hospital. This is based on an instrument [1] developed in a comparative study in an emergency ward in the USA and used for physicians. 60 of 154 staff members (physicians and nurses) completed the questionnaire, corresponding to a response rate of 39%. The definition of palliative care (n=60) was very mixed and could be classified into 6 areas. In response to questions about specific services, the staff members mentioned that their access to existing patient data should be facilitated. They also expressed the wish for a 24 h palliative consultation service and thought that, during normal working days, more time should be allotted to discussing issues related to palliative care. It has been confirmed that the definition of palliative care is not consistent. Within the UNZ, there is no clear procedure, but lack of time for detailed discussions with patients needing palliative care. Patient wishes or living wills with the DNR/DNI procedure do not contradict the personal ethics of most staff members. UNZ staff members would welcome the 24 h availability of a specialized PC team, as well as the development of guidelines and increased training in PC.

Palliative Care Bedside Teaching: A Qualitative Analysis of Medical Students' Reflective Writings after Clinical Practices.

PubMed

Rojí, Rocío; Noguera-Tejedor, Antonio; Pikabea-Díaz, Fernando; Carrasco, José Miguel; Centeno, Carlos

2017-02-01

A mandatory course in palliative care (PC) is organized for all final-year medical students at the University of Navarre. It consists of 24 lectures, 4 workshops, and 1 scheduled five hour clinical PC service experience at two different sites. In the 48 hours after the visit and related to the clinical experience, each student has to complete a 500-word reflective writing (RW) piece. To investigate how a brief PC clinical experience helps equip the medical student. Qualitative study of RW. Two researchers produced a content analysis of students' RW. They collaboratively developed themes and categories with a constant review of the classification tree and an exhaustive collection of quotes. Differences between services were analyzed (λ 2 ). One hundred sixty-seven RW were analyzed from the 197 students on the course (response rate 85%). Six major themes emerged: All the students identified central aspects of PC work dynamics; students acquired specific PC knowledge (86%); the personal influence of the experience was reported (68%); students described how patients and their caregivers deal with the patients' illness (68%); students talked about the essence of PC and essential aspects of medicine (42%); students reported spontaneously having changed their assumptions about PC (15%); and they realized that the experience was relevant to all clinical practice. Categories such as teamwork, the expression of patients' and caregivers' feelings, and family devotion showed statistical differences between services (λ 2 p < 0.05). A short bedside clinical experience in PC, encouraging student reflection, provides a deeper understanding of PC and even of core medicine values. The data we gather cannot explain only new skill acquisition but seems to suggest a life-changing personal experience for the student.

Euthanasia embedded in palliative care. Responses to essentialistic criticisms of the Belgian model of integral end-of-life care.

PubMed

Bernheim, Jan L; Raus, Kasper

2017-08-01

The Belgian model of 'integral' end-of-life care consists of universal access to palliative care (PC) and legally regulated euthanasia. As a first worldwide, the Flemish PC organisation has embedded euthanasia in its practice. However, some critics have declared the Belgian-model concepts of 'integral PC' and 'palliative futility' to fundamentally contradict the essence of PC. This article analyses the various essentialistic arguments for the incompatibility of euthanasia and PC. The empirical evidence from the euthanasia-permissive Benelux countries shows that since legalisation, carefulness (of decision making) at the end of life has improved and there have been no significant adverse 'slippery slope' effects. It is problematic that some critics disregard the empirical evidence as epistemologically irrelevant in a normative ethical debate. Next, rejecting euthanasia because its prevention was a founding principle of PC ignores historical developments. Further, critics' ethical positions depart from the PC tenet of patient centeredness by prioritising caregivers' values over patients' values. Also, many critics' canonical adherence to the WHO definition of PC, which has intention as the ethical criterion is objectionable. A rejection of the Belgian model on doctrinal grounds also has nefarious practical consequences such as the marginalisation of PC in euthanasia-permissive countries, the continuation of clandestine practices and problematic palliative sedation until death. In conclusion, major flaws of essentialistic arguments against the Belgian model include the disregard of empirical evidence, appeals to canonical and questionable definitions, prioritisation of caregiver perspectives over those of patients and rejection of a plurality of respectable views on decision making at the end of life. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Pleiotropy between genetic markers of obesity and risk of prostate cancer

PubMed Central

Edwards, Todd L.; Giri, Ayush; Motley, Saundra; Duong, Wynne; Fowke, Jay H.

2013-01-01

Background To address inconsistent findings of obesity and prostate cancer risk, we analyzed the association between prostate cancer (PC) and genetic markers of obesity and metabolism. Methods Analyses included 176,520 single nucleotide polymorphisms (SNPs) associated with 23 metabolic traits. We examined the association between SNPs and PC in 871 cases and 906 controls, including 427 high-grade cases with Gleason ≥7. Genetic risk scores (GRSs) for body mass index (BMI) and waist-to-hip ratio (WHR) were also created by summing alleles associated with increasing BMI or WHR. Results PC was associated with 5 loci, including cyclin M2, with p-values less than 1×10−4. In addition, the WHR GRS was associated with high-grade PC versus controls (OR: 1.05; 95% CI: 1.00 – 1.11, p-value = 0.048), and high-grade PC versus low-grade PC (OR: 1.07, 95% CI 1.01 – 1.13, p-value = 0.03). None of these findings exceed the threshold for significance after correction for multiple testing. Conclusions Variants in genes known to be associated with metabolism and obesity may be associated with PC. We show evidence for pleiotropy between WHR GRS and PC grade. This finding is consistent with the function of several WHR genes, and previously described relationships with cancer traits. Impact Limitations in standard obesity measures suggest alternative characterizations of obesity may be needed to understand the role of metabolic dysregulation in PC. The underlying genetics of WHR or other Metabochip SNPs, while not statistically significant beyond multiple testing thresholds within our sample size, support the metabolic hypothesis of prostate carcinogenesis and warrant further investigation in independent samples. PMID:23810916

High fidelity computational characterization of the mechanical response of thermally aged polycarbonate

NASA Astrophysics Data System (ADS)

Zhang, Zesheng; Zhang, Lili; Jasa, John; Li, Wenlong; Gazonas, George; Negahban, Mehrdad

2017-07-01

A representative all-atom molecular dynamics (MD) system of polycarbonate (PC) is built and conditioned to capture and predict the behaviours of PC in response to a broad range of thermo-mechanical loadings for various thermal aging. The PC system is constructed to have a distribution of molecular weights comparable to a widely used commercial PC (LEXAN 9034), and thermally conditioned to produce models for aged and unaged PC. The MD responses of these models are evaluated through comparisons to existing experimental results carried out at much lower loading rates, but done over a broad range of temperatures and loading modes. These experiments include monotonic extension/compression/shear, unilaterally and bilaterally confined compression, and load-reversal during shear. It is shown that the MD simulations show both qualitative and quantitative similarity with the experimental response. The quantitative similarity is evaluated by comparing the dilatational response under bilaterally confined compression, the shear flow viscosity and the equivalent yield stress. The consistency of the in silico response to real laboratory experiments strongly suggests that the current PC models are physically and mechanically relevant and potentially can be used to investigate thermo-mechanical response to loading conditions that would not easily be possible. These MD models may provide valuable insight into the molecular sources of certain observations, and could possibly offer new perspectives on how to develop constitutive models that are based on better understanding the response of PC under complex loadings. To this latter end, the models are used to predict the response of PC to complex loading modes that would normally be difficult to do or that include characteristics that would be difficult to measure. These include the responses of unaged and aged PC to unilaterally confined extension/compression, cyclic uniaxial/shear loadings, and saw-tooth extension/compression/shear.

Linewidth Narrowing and Purcell Enhancement in Photonic Crystal Cavities on an Er-Doped Silicon Nitride Platform

DTIC Science & Technology

2010-02-01

Low noise superconducting single photon detectors on silicon,” Appl. Phys. Lett. 93, 131101 (2008). 20. M. T. Tanner, C. M. Natarajan, V. K... wavelength sensitivity in NbTiN superconducting nanowire single-photon detectors fabricated on oxidized silicon substrates,” Proceedings of Single...cavity resonance wavelength and Q-factor for the PC cavity are shown in Figure 3. The data are taken both at low (0.050 mW) pump power and high (30 mW

Velocity Measurement in Carotid Artery: Quantitative Comparison of Time-Resolved 3D Phase-Contrast MRI and Image-based Computational Fluid Dynamics

PubMed Central

Sarrami-Foroushani, Ali; Nasr Esfahany, Mohsen; Nasiraei Moghaddam, Abbas; Saligheh Rad, Hamidreza; Firouznia, Kavous; Shakiba, Madjid; Ghanaati, Hossein; Wilkinson, Iain David; Frangi, Alejandro Federico

2015-01-01

Background: Understanding hemodynamic environment in vessels is important for realizing the mechanisms leading to vascular pathologies. Objectives: Three-dimensional velocity vector field in carotid bifurcation is visualized using TR 3D phase-contrast magnetic resonance imaging (TR 3D PC MRI) and computational fluid dynamics (CFD). This study aimed to present a qualitative and quantitative comparison of the velocity vector field obtained by each technique. Subjects and Methods: MR imaging was performed on a 30-year old male normal subject. TR 3D PC MRI was performed on a 3 T scanner to measure velocity in carotid bifurcation. 3D anatomical model for CFD was created using images obtained from time-of-flight MR angiography. Velocity vector field in carotid bifurcation was predicted using CFD and PC MRI techniques. A statistical analysis was performed to assess the agreement between the two methods. Results: Although the main flow patterns were the same for the both techniques, CFD showed a greater resolution in mapping the secondary and circulating flows. Overall root mean square (RMS) errors for all the corresponding data points in PC MRI and CFD were 14.27% in peak systole and 12.91% in end diastole relative to maximum velocity measured at each cardiac phase. Bland-Altman plots showed a very good agreement between the two techniques. However, this study was not aimed to validate any of methods, instead, the consistency was assessed to accentuate the similarities and differences between Time-resolved PC MRI and CFD. Conclusion: Both techniques provided quantitatively consistent results of in vivo velocity vector fields in right internal carotid artery (RCA). PC MRI represented a good estimation of main flow patterns inside the vasculature, which seems to be acceptable for clinical use. However, limitations of each technique should be considered while interpreting results. PMID:26793288

Sb-Te Phase-change Materials under Nanoscale Confinement

NASA Astrophysics Data System (ADS)

Ihalawela, Chandrasiri A.

Size, speed and efficiency are the major challenges of next generation nonvolatile memory (NVM), and phase-change memory (PCM) has captured a great attention due to its promising features. The key for PCM is rapid and reversible switching between amorphous and crystalline phases with optical or electrical excitation. The structural transition is associated with significant contrast in material properties which can be utilized in optical (CD, DVD, BD) and electronic (PCRAM) memory applications. Importantly, both the functionality and the success of PCM technology significantly depend on the core material and its properties. So investigating PC materials is crucial for the development of PCM technology to realized enhanced solutions. In regards to PC materials, Sb-Te binary plays a significant role as a basis to the well-known Ge-Sb-Te system. Unlike the conventional deposition methods (sputtering, evaporation), electrochemical deposition method is used due to its multiple advantages, such as conformality, via filling capability, etc. First, the controllable synthesis of Sb-Te thin films was studied for a wide range of compositions using this novel deposition method. Secondly, the solid electrolytic nature of stoichiometric Sb2Te3 was studied with respect to precious metals. With the understanding of 2D thin film synthesis, Sb-Te 1D nanowires (18 - 220 nm) were synthesized using templated electrodeposition, where nanoporous anodic aluminum oxide (AAO) was used as a template for the growth of nanowires. In order to gain the controllability over the deposition in high aspect ratio structures, growth mechanisms of both the thin films and nanowires were investigated. Systematic understanding gained thorough previous studies helped to formulate the ultimate goal of this dissertation. In this dissertation, the main objective is to understand the size effect of PC materials on their phase transition properties. The reduction of effective memory cell size in conjunction with multilevel cells could be promising to achieve high data densities. However the size reduction may result in changes in material properties. If phase transition properties of the materials are also tunable with respect to the size, then more attractive solutions could be realized. So we have reported the size effect on crystallization temperature of prototypical Sb2Te3 nanowires synthesized in AAO templates. Moreover, we have found that the reduction of nanowire size can elevate the crystallization temperature, which is crucial for data retention in PCM technology. Energy dispersive X-ray spectroscopy, X-ray diffraction, electron microscopy and electrical resistivity measurements were used to characterize the composition, structure, morphology, and phase transition properties of the materials. We believe that this dissertation will provide new insights into the size effect of PC materials in addition to the controllable synthesis of PC thin films and nanowires through the novel electrochemical method.

Two-dimensional Cu2Si sheet: a promising electrode material for nanoscale electronics.

PubMed

Yam, Kah Meng; Guo, Na; Zhang, Chun

2018-06-15

Building electronic devices on top of two-dimensional (2D) materials has recently become one of most interesting topics in nanoelectronics. Finding high-performance 2D electrode materials is one central issue in 2D nanoelectronics. In the current study, based on first-principles calculations, we compare the electronic and transport properties of two nanoscale devices. One device consists of two single-atom-thick planar Cu 2 Si electrodes, and a nickel phthalocyanine (NiPc) molecule in the middle. The other device is made of often-used graphene electrodes and a NiPc molecule. Planer Cu 2 Si is a new type of 2D material that was recently predicted to exist and be stable under room temperature [11]. We found that at low bias voltages, the electric current through the Cu 2 Si-NiPc-Cu 2 Si junction is about three orders higher than that through graphene-NiPc-graphene. Detailed analysis shows that the surprisingly high conductivity of Cu 2 Si-NiPc-Cu 2 Si originates from the mixing of the Cu 2 Si state near Fermi energy and the highest occupied molecular orbital of NiPc. These results suggest that 2D Cu 2 Si may be an excellent candidate for electrode materials for future nanoscale devices.

Porous silicon-copper phthalocyanine heterostructure based photoelectrochemical cell

NASA Astrophysics Data System (ADS)

A. Betty, C.; N, Padma; Arora, Shalav; Survaiya, Parth; Bhattacharya, Debarati; Choudhury, Sipra; Roy, Mainak

2018-01-01

A hybrid solar cell consisting of nanostructured p-type porous silicon (PS) deposited with visible light absorbing dye, Copper Phthalocyanine (CuPc) has been prepared in the photoelectrochemical cell configuration. P-type PS with (100) and (111) orientations which have different porous structures were used for studying the effects of the substrate morphology on the cell efficiency. Heterostructures were prepared by depositing three different thicknesses of CuPc for optimizing the cell efficiency. Structural and surface characterizations were studied using XRD, Raman, SEM and AFM on the PS-CuPc heterostructure. XRD spectrum on both plane silicon and porous silicon indicates the π-π stacking of CuPc with increased disorder for CuPc film on porous silicon. Electrochemical characterizations under sun light type radiation have been carried out to evaluate the photosensitivity of the heterostructure. Between the two different substrates, (100) PS gives better photocurrent, possibly due to the higher surface area and lower series resistance of the structure. Among the (100) PS substrates, (100) PS with 15 nm CuPc film gives Voc more than 1 V resulting in higher efficiency for the cell. The study suggests the scope for optimization of solar cell efficiency using various combinations of the substrate structure and thickness of the sensitizing layer.

Cohort profile: the chronic kidney disease prognosis consortium.

PubMed

Matsushita, Kunihiro; Ballew, Shoshana H; Astor, Brad C; Jong, Paul E de; Gansevoort, Ron T; Hemmelgarn, Brenda R; Levey, Andrew S; Levin, Adeera; Wen, Chi-Pang; Woodward, Mark; Coresh, Josef

2013-12-01

The Chronic Kidney Disease Prognosis Consortium (CKD-PC) was established in 2009 to provide comprehensive evidence about the prognostic impact of two key kidney measures that are used to define and stage CKD, estimated glomerular filtration rate (eGFR) and albuminuria, on mortality and kidney outcomes. CKD-PC currently consists of 46 cohorts with data on these kidney measures and outcomes from >2 million participants spanning across 40 countries/regions all over the world. CKD-PC published four meta-analysis articles in 2010-11, providing key evidence for an international consensus on the definition and staging of CKD and an update for CKD clinical practice guidelines. The consortium continues to work on more detailed analysis (subgroups, different eGFR equations, other exposures and outcomes, and risk prediction). CKD-PC preferably collects individual participant data but also applies a novel distributed analysis model, in which each cohort runs statistical analysis locally and shares only analysed outputs for meta-analyses. This distributed model allows inclusion of cohorts which cannot share individual participant level data. According to agreement with cohorts, CKD-PC will not share data with third parties, but is open to including further eligible cohorts. Each cohort can opt in/out for each topic. CKD-PC has established a productive and effective collaboration, allowing flexible participation and complex meta-analyses for studying CKD.

Polychromatic flow cytometry is more sensitive than microscopy in detecting small monoclonal plasma cell populations.

PubMed

Tran, Daniel N; Smith, Sandy A B C; Brown, David A; Parker, Andrew J C; Joseph, Joanne E; Armstrong, Nicola; Sewell, William A

2017-03-01

There is an emerging role for flow cytometry (FC) in the assessment of small populations of plasma cells (PC). However, FC's utility has been questioned due to consistent underestimation of the percentage of PC compared to microscopy. A retrospective study was performed on bone marrow samples analysed by 8-colour FC. Plasma cell populations were classified as polyclonal or monoclonal based on FC analysis. FC findings were compared with microscopy of aspirates, histology and immunohistochemistry of trephine biopsies, and immunofixation (IFX) of serum and/or urine. FC underestimated PC compared to aspirate and trephine microscopy. The 10% diagnostic cutoff for MM on aspirate microscopy corresponded to a 3.5% cutoff on FC. Abnormal plasma cell morphology by aspirate microscopy and clonality by FC correlated in 229 of 294 cases (78%). However, in 50 cases, FC demonstrated a monoclonal population but microscopy reported no abnormality. In 15 cases, abnormalities were reported by microscopy but not by FC. Clonality assessment by trephine microscopy and FC agreed in 251/280 cases (90%), but all 29 discordant cases were monoclonal by FC and not monoclonal by microscopy. These cases had fewer PC and proportionally more polyclonal PC, and when IFX detected a paraprotein, it had the same light chain as in the PC determined by FC. FC was more sensitive in detecting monoclonal populations that were small or accompanied by polyclonal PC. This study supports the inclusion of FC in the evaluation of PC, especially in the assessment of small populations. © 2016 International Clinical Cytometry Society. © 2016 International Clinical Cytometry Society.

Molecular cloning and characterization of prohormone convertase 1 gene in abalone (Haliotis diversicolor supertexta).

PubMed

Zhou, Jin; Cai, Zhong-hua

2010-03-01

Prohormone convertases (PCs) are calcium-dependent serine endoproteases of the subtilisin family that play a key role in the posttranslational processing of precursors for bioactive peptides. In this study, the cDNA of PC1 from abalone (Haliotis diversicolor supertexta) was cloned and sequenced. The PC1 cDNA consisted of 2216 bp with an open reading frame of 2010 bp encoding a 670 amino acid peptide. Comparative structural analysis revealed that abalone PC1 shared high similarity and identity with most PC counterparts. The profile of deduced peptide of PC1 was composed of an N-terminal signal peptide, a prosegment domain, a catalytic domain and a P domain, which were common in many species. Sequence analysis indicated that the abalone PC1 was highly conserved in catalytic domain, including three conserved serine catalytic signatures that comprised a catalytic triad active center. Also conserved were the potential cleavage site for release of the mature peptide, a cognate integrin binding site RGD in P domain, and four cysteine residues involved in forming an intrachain disulfide bridge. To further investigate the functions of PC1 in abalone, real-time quantitative PCR was performed to determine the expression level of this gene at three different reproduction stages (i.e. pre-, during- and post-breeding). Results indicated that PC1 was expressed throughout the three stages but the expression levels varied with the timepoints and different tissues in abalone. The expression levels of PC1 in digestive gland were much higher than those of the gonad. In female abalone, the expression of PC1 was higher at pre-breeding and during-breeding stages (P<0.05), and the expression declined at the subsequent stage. Whereas, the level of PC1 in male individual did not exhibit a significant difference in various reproduction stages. Also, the natural enzyme activity of PC1 partially exhibited a similar tendency with the mRNA expression. According to the results, it can be concluded that PC1 gene is involved in the abalone reproduction process (e.g. spawning or sperming). PC1 is a potential prohormone processing enzyme and it may play a critical role in abalone physiological processes related to reproduction. 2009 Elsevier Inc. All rights reserved.

An Open-Circuit Voltage and Power Conversion Efficiency Study of Fullerene Ternary Organic Solar Cells Based on Oligomer/Oligomer and Oligomer/Polymer.

PubMed

Zhang, Guichuan; Zhou, Cheng; Sun, Chen; Jia, Xiaoe; Xu, Baomin; Ying, Lei; Huang, Fei; Cao, Yong

2017-07-01

Variations in the open-circuit voltage (V oc ) of ternary organic solar cells are systematically investigated. The initial study of these devices consists of two electron-donating oligomers, S2 (two units) and S7 (seven units), and the electron-accepting [6,6]-phenyl C71 butyric acid methyl ester (PC 71 BM) and reveals that the V oc is continuously tunable due to the changing energy of the charge transfer state (E ct ) of the active layers. Further investigation suggests that V oc is also continuously tunable upon change in E ct in a ternary blend system that consists of S2 and its corresponding polymer (P11):PC 71 BM. It is interesting to note that higher power conversion efficiencies can be obtained for both S2:S7:PC 71 BM and S2:P11:PC 71 BM ternary systems compared with their binary systems, which can be ascribed to an improved V oc due to the higher E ct and an improved fill factor due to the improved film morphology upon the incorporation of S2. These findings provide a new guideline for the future design of conjugated polymers for achieving higher performance of ternary organic solar cells. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Blistering of langmuir-blodgett bilayers containing anionic phospholipids as observed by atomic force microscopy.

PubMed Central

Rinia, H A; Demel, R A; van der Eerden, J P; de Kruijff, B

1999-01-01

Asymmetric bilayers of different phospholipid compositions have been prepared by the Langmuir-Blodgett (L-B) method, and imaged by atomic force microscopy (AFM). Such bilayers can function as a model for biological membranes. The first leaflet consisted of zwitterionic phospholipids phosphatidylcholine (PC) or phosphatidylethanolamine (PE). The second leaflet consisted of the anionic phospholipid phosphatidylglycerol (PG), in either the condensed or liquid phase or, for comparison, of PC. Different bilayers showed different morphology. In all bilayers defects in the form of holes were present. In some bilayers with a first leaflet consisting of PC, polygonal line-shaped defects were observed, whereas when the first leaflet consisted of PE, mainly round defects were seen. Not only the shape, but also the amount of defects varied, depending on the condition and the composition of the second leaflet. In most of the PG-containing systems the defects were surrounded by elevations, which reversibly disappeared in the presence of divalent cations. This is the first time that such elevations have been observed on phospholipid bilayers. We propose that they are induced by phospholipid exchange between the two leaflets around the defects, leading to the presence of negatively charged phospholipids in the first leaflet. Because the substrate is also negatively charged, the bilayer around the edges is repelled and lifted up. Since it was found that the elevations are indeed detached from the substrate, we refer to this effect as bilayer blistering. PMID:10465778

Reducing background noise in near-infrared medical imaging: Routes to activated fluorescing

NASA Astrophysics Data System (ADS)

Burdette, Mary K.; Bandera, Yuriy; Powell, Rhonda R.; Bruce, Terri F.; Foulger, Stephen H.

2016-03-01

Activated fluorescence was achieved for nanoparticle based systems. One particulate system consisting of a poly(propargyl acrylate) (PA) core with covalently attached derivatized fluorescein and modified bovine serum albumin covalently conjugated to a cyanine 3 derivative was initially nonfluorescent. Upon trypsin addition and subsequent proteolytic digestion, Förster resonance energy transfer (FRET) was induced. The other particulate system consisted of a PA core with covalently attached azide modified BSA, which was covalently attached to a silicon phthalocyanine derivative (PA/BSA/akSiPc600). Both systems were biocompatible. To investigate activated fluorescence with the PA/BSA/akSiPc600 system in cancer cells, human non-small cell lung cancer cells (A549 cell line) were used as a model system. The PA/BSA/akSiPc600 system was incubated with the cells at varying time points in an effort to see a fluorescence increase over time as the cells uptake the particles and as they digest the BSA, most probably, via endocytosis. It was seen, through live cell scanning confocal microscopy, that the fluorescence was activated in the cell.

A PC-based telemetry system for acquiring and reducing data from multiple PCM streams

NASA Astrophysics Data System (ADS)

Simms, D. A.; Butterfield, C. P.

1991-07-01

The Solar Energy Research Institute's (SERI) Wind Research Program is using Pulse Code Modulation (PCM) Telemetry Data-Acquisition Systems to study horizontal-axis wind turbines. Many PCM systems are combined for use in test installations that require accurate measurements from a variety of different locations. SERI has found them ideal for data-acquisition from multiple wind turbines and meteorological towers in wind parks. A major problem has been in providing the capability to quickly combine and examine incoming data from multiple PCM sources in the field. To solve this problem, SERI has developed a low-cost PC-based PCM Telemetry Data-Reduction System (PC-PCM System) to facilitate quick, in-the-field multiple-channel data analysis. The PC-PCM System consists of two basic components. First, PC-compatible hardware boards are used to decode and combine multiple PCM data streams. Up to four hardware boards can be installed in a single PC, which provides the capability to combine data from four PCM streams directly to PC disk or memory. Each stream can have up to 62 data channels. Second, a software package written for use under DOS was developed to simplify data-acquisition control and management. The software, called the Quick-Look Data Management Program, provides a quick, easy-to-use interface between the PC and multiple PCM data streams. The Quick-Look Data Management Program is a comprehensive menu-driven package used to organize, acquire, process, and display information from incoming PCM data streams. The paper describes both hardware and software aspects of the SERI PC-PCM system, concentrating on features that make it useful in an experiment test environment to quickly examine and verify incoming data from multiple PCM streams. Also discussed are problems and techniques associated with PC-based telemetry data-acquisition, processing, and real-time display.

The impact of intermittent versus continuous exposure to EGFR tyrosine kinase inhibitor on selection of EGFR T790M-mutant drug-resistant clones in a lung cancer cell line carrying activating EGFR mutation

PubMed Central

Lee, Youngjoo; Choi, Yu-Ra; Kim, Kyoung-Yeon; Shin, Dong Hoon

2016-01-01

Drug-resistant cell lines are essential tools for investigating the mechanisms of resistance to molecular-targeted anti-cancer drugs. However, little is known about how to establish clinically relevant drug-resistant cell lines. Our study examined the impact of a drug-free period on the establishment of a cell line with clinically relevant resistance to molecular-targeted drugs. We used PC9 cells, a lung cancer cell line carrying EGFR mutation, because this is a validated target for EGFR tyrosine kinase inhibitors (TKI). PC9 cells were intermittently or continuously exposed to increasing concentrations of gefitinib (0.01 μM to 1.0 μM) and the emergence of the most common acquired resistance mutation in EGFR, T790M, was determined. T790M was detected at a 25-fold lower drug concentration in cells continuously exposed to gefitinib (PC9/GRc) than in cells intermittently exposed to gefitinib (PC9/GRi) (0.04 μM vs 1.0 μM, respectively). The mutation frequencies at those drug concentrations were 19.8% and 8.0% in PC9/GRc and PC9/GRi cells, respectively. After drug-free culture for 8 weeks, resistance to gefitinib decreased in the PC9/GRi cells but not in the PC9/GRc cells. In the PC9/GRc cells, the frequency of the T790M mutation was consistently about 20% from 0.04 μM to 1.0 μM of gefitinib. In the PC9/GRc cells, the T790M mutation was detected in all single-cell clones, at frequencies ranging from 7.0% to 37.0%, with a median of 19.5% (95% confidence interval, 17.3%–20.9%). In conclusion, compared with intermittent drug exposure, continuous exposure might select better minor drug-resistant clones when creating cell lines resistant to molecular-targeted drugs. PMID:27270313

The impact of intermittent versus continuous exposure to EGFR tyrosine kinase inhibitor on selection of EGFR T790M-mutant drug-resistant clones in a lung cancer cell line carrying activating EGFR mutation.

PubMed

Lee, Youngjoo; Choi, Yu-Ra; Kim, Kyoung-Yeon; Shin, Dong Hoon

2016-07-12

Drug-resistant cell lines are essential tools for investigating the mechanisms of resistance to molecular-targeted anti-cancer drugs. However, little is known about how to establish clinically relevant drug-resistant cell lines. Our study examined the impact of a drug-free period on the establishment of a cell line with clinically relevant resistance to molecular-targeted drugs. We used PC9 cells, a lung cancer cell line carrying EGFR mutation, because this is a validated target for EGFR tyrosine kinase inhibitors (TKI). PC9 cells were intermittently or continuously exposed to increasing concentrations of gefitinib (0.01 μM to 1.0 μM) and the emergence of the most common acquired resistance mutation in EGFR, T790M, was determined. T790M was detected at a 25-fold lower drug concentration in cells continuously exposed to gefitinib (PC9/GRc) than in cells intermittently exposed to gefitinib (PC9/GRi) (0.04 μM vs 1.0 μM, respectively). The mutation frequencies at those drug concentrations were 19.8% and 8.0% in PC9/GRc and PC9/GRi cells, respectively. After drug-free culture for 8 weeks, resistance to gefitinib decreased in the PC9/GRi cells but not in the PC9/GRc cells. In the PC9/GRc cells, the frequency of the T790M mutation was consistently about 20% from 0.04 μM to 1.0 μM of gefitinib. In the PC9/GRc cells, the T790M mutation was detected in all single-cell clones, at frequencies ranging from 7.0% to 37.0%, with a median of 19.5% (95% confidence interval, 17.3%-20.9%). In conclusion, compared with intermittent drug exposure, continuous exposure might select better minor drug-resistant clones when creating cell lines resistant to molecular-targeted drugs.

Cost and performance of coal-based energy in Brazil

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

Temchin, J.; DeLallo, M.R.

1998-07-01

As part of the US Department of Energy's (DOE) efforts to establish the strategic benefits of Clean Coal Technologies (CCT), there is a need to evaluate the specific market potential where coal is a viable option. One such market is Brazil, where significant growth in economic development requires innovative and reliable technologies to support the use of domestic coal. While coal is Brazil's most abundant and economic fossil energy resource, it is presently under utilized in the production of electrical power. This report presents conceptual design for pulverized coal (PC) and circulating fluidized-bed combustion (CFBC) options with resulting capital, operatingmore » and financial parameters based on Brazil application conditions. Recent PC and CFBC plant capital costs have dropped with competition in the generation market and have established a competitive position in power generation. Key issues addressed in this study include: Application of market based design approach for FBC and PC, which is competitive within the current domestic, and international power generation markets. Design, fabrication, purchase, and construction methods which reduce capital investment while maintaining equipment quality and plant availability. Impact on coast and performance from application of Brazilian coals, foreign trade and tax policies, construction logistics, and labor requirements. Nominal production values of 200 MWe and 400 MWe were selected for the CFBC power plant and 400 MWe for the PC. The 400 MWe size was chosen to be consistent with the two largest Brazilian PC units. Fluidized bed technology, with limited experience in single units over 200 MW, would consist of two 200 MWe circulating fluidized bed boilers supplying steam to one steam turbine for the 400 MWe capacity. A 200 MWe capacity unit was also developed for CFBC option to support opportunities in re-powering and where specific site or other infrastructure constraints limit production.« less

Physiological Response of Crocosphaera watsonii to Enhanced and Fluctuating Carbon Dioxide Conditions

PubMed Central

Gradoville, Mary R.; White, Angelicque E.; Letelier, Ricardo M.

2014-01-01

We investigated the effects of elevated pCO2 on cultures of the unicellular N2-fixing cyanobacterium Crocosphaera watsonii WH8501. Using CO2-enriched air, cultures grown in batch mode under high light intensity were exposed to initial conditions approximating current atmospheric CO2 concentrations (∼400 ppm) as well as CO2 levels corresponding to low- and high-end predictions for the year 2100 (∼750 and 1000 ppm). Following acclimation to CO2 levels, the concentrations of particulate carbon (PC), particulate nitrogen (PN), and cells were measured over the diurnal cycle for a six-day period spanning exponential and early stationary growth phases. High rates of photosynthesis and respiration resulted in biologically induced pCO2 fluctuations in all treatments. Despite this observed pCO2 variability, and consistent with previous experiments conducted under stable pCO2 conditions, we observed that elevated mean pCO2 enhanced rates of PC production, PN production, and growth. During exponential growth phase, rates of PC and PN production increased by ∼1.2- and ∼1.5-fold in the mid- and high-CO2 treatments, respectively, when compared to the low-CO2 treatment. Elevated pCO2 also enhanced PC and PN production rates during early stationary growth phase. In all treatments, PC and PN cellular content displayed a strong diurnal rhythm, with particulate C:N molar ratios reaching a high of 22∶1 in the light and a low of 5.5∶1 in the dark. The pCO2 enhancement of metabolic rates persisted despite pCO2 variability, suggesting a consistent positive response of Crocosphaera to elevated and fluctuating pCO2 conditions. PMID:25343645

Anti-Tumor Activity of a Novel Compound-CDF Is Mediated by Regulating miR-21, miR-200, and PTEN in Pancreatic Cancer

PubMed Central

Kong, Dejuan; Sarkar, Sanila H.; Wang, Zhiwei; Banerjee, Sanjeev; Aboukameel, Amro; Padhye, Subhash; Philip, Philip A.; Sarkar, Fazlul H.

2011-01-01

Background The existence of cancer stem cells (CSCs) or cancer stem-like cells in a tumor mass is believed to be responsible for tumor recurrence because of their intrinsic and extrinsic drug-resistance characteristics. Therefore, targeted killing of CSCs would be a newer strategy for the prevention of tumor recurrence and/or treatment by overcoming drug-resistance. We have developed a novel synthetic compound-CDF, which showed greater bioavailability in animal tissues such as pancreas, and also induced cell growth inhibition and apoptosis, which was mediated by inactivation of NF-κB, COX-2, and VEGF in pancreatic cancer (PC) cells. Methodology/Principal Findings In the current study we showed, for the first time, that CDF could significantly inhibit the sphere-forming ability (pancreatospheres) of PC cells consistent with increased disintegration of pancreatospheres, which was associated with attenuation of CSC markers (CD44 and EpCAM), especially in gemcitabine-resistant (MIAPaCa-2) PC cells containing high proportion of CSCs consistent with increased miR-21 and decreased miR-200. In a xenograft mouse model of human PC, CDF treatment significantly inhibited tumor growth, which was associated with decreased NF-κB DNA binding activity, COX-2, and miR-21 expression, and increased PTEN and miR-200 expression in tumor remnants. Conclusions/Significance These results strongly suggest that the anti-tumor activity of CDF is associated with inhibition of CSC function via down-regulation of CSC-associated signaling pathways. Therefore, CDF could be useful for the prevention of tumor recurrence and/or treatment of PC with better treatment outcome in the future. PMID:21408027

A low-cost PC-based telemetry data-reduction system

NASA Astrophysics Data System (ADS)

Simms, D. A.; Butterfield, C. P.

1990-04-01

The Solar Energy Research Institute's (SERI) Wind Research Branch is using Pulse Code Modulation (PCM) telemetry data-acquisition systems to study horizontal-axis wind turbines. PCM telemetry systems are used in test installations that require accurate multiple-channel measurements taken from a variety of different locations. SERI has found them ideal for use in tests requiring concurrent acquisition of data-reduction system to facilitate quick, in-the-field multiple-channel data analysis. Called the PC-PCM System, it consists of two basic components. First, AT-compatible hardware boards are used for decoding and combining PCM data streams. Up to four hardware boards can be installed in a single PC, which provides the capability to combine data from four PCM streams directly to PC disk or memory. Each stream can have up to 62 data channels. Second, a software package written for the DOS operating system was developed to simplify data-acquisition control and management. The software provides a quick, easy-to-use interface between the PC and PCM data streams. Called the Quick-Look Data Management Program, it is a comprehensive menu-driven package used to organize, acquire, process, and display information from incoming PCM data streams. This paper describes both hardware and software aspects of the SERI PC-PCM system, concentrating on features that make it useful in an experiment test environment to quickly examine and verify incoming data. Also discussed are problems and techniques associated with PC-based telemetry data acquisition, processing, and real-time display.

A robust and efficient stepwise regression method for building sparse polynomial chaos expansions

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

Abraham, Simon, E-mail: Simon.Abraham@ulb.ac.be; Raisee, Mehrdad; Ghorbaniasl, Ghader

2017-03-01

Polynomial Chaos (PC) expansions are widely used in various engineering fields for quantifying uncertainties arising from uncertain parameters. The computational cost of classical PC solution schemes is unaffordable as the number of deterministic simulations to be calculated grows dramatically with the number of stochastic dimension. This considerably restricts the practical use of PC at the industrial level. A common approach to address such problems is to make use of sparse PC expansions. This paper presents a non-intrusive regression-based method for building sparse PC expansions. The most important PC contributions are detected sequentially through an automatic search procedure. The variable selectionmore » criterion is based on efficient tools relevant to probabilistic method. Two benchmark analytical functions are used to validate the proposed algorithm. The computational efficiency of the method is then illustrated by a more realistic CFD application, consisting of the non-deterministic flow around a transonic airfoil subject to geometrical uncertainties. To assess the performance of the developed methodology, a detailed comparison is made with the well established LAR-based selection technique. The results show that the developed sparse regression technique is able to identify the most significant PC contributions describing the problem. Moreover, the most important stochastic features are captured at a reduced computational cost compared to the LAR method. The results also demonstrate the superior robustness of the method by repeating the analyses using random experimental designs.« less

Crystal engineering: co-crystals of cinnamic acid derivatives with a pyridyl derivative co-crystallizer.

PubMed

Lorenzo, Daniel A; Forrest, Sebastian J K; Sparkes, Hazel A

2016-02-01

A number of hydrogen-bonded co-crystals, consisting of a cinnamic acid derivative and a pyridyl co-crystallizer, have been synthesized and their properties investigated by X-ray diffraction. Samples were prepared by recrystallization or solvent drop grinding of trans-cinnamic acid (1), 4-methylcinnamic acid (2), 4-methoxy cinnamic acid (3) or 3,4-methoxy cinnamic acid (4), with 4,4-dipyridyl (A), iso-nicotinamide (B) or nicotinamide (C). The X-ray single-crystal structures of seven novel co-crystals, obtained through recrystallization, are examined and the hydrogen-bonding interactions discussed. Consistent hydrogen-bonding motifs were observed for samples prepared when using 4,4-dipyridyl (A) or iso-nicotinamide (B) as the co-crystallizing agent. Powder X-ray diffraction analysis of the samples prepared by solvent drop grinding suggests the formation of ten co-crystals.

A modified hexagonal photonic crystal fiber for terahertz applications

NASA Astrophysics Data System (ADS)

Islam, Md. Saiful; Sultana, Jakeya; Faisal, Mohammad; Islam, Mohammad Rakibul; Dinovitser, Alex; Ng, Brian W.-H.; Abbott, Derek

2018-05-01

We present a Zeonex based highly birefringent and dispersion flattened porous core photonic crystal fiber (PC-PCF) for polarization preserving applications in the terahertz region. In order to facilitate birefringence, an array of elliptical shaped air holes surrounded by porous cladding is introduced. The porous cladding comprises circular air-holes in a modified hexagonal arrangement. The transmission characteristics of the proposed PCF are investigated using a full-vector finite element method with perfectly matched layer (PML) absorbing boundary conditions. Simulation results show a high birefringence of 0.086 and an ultra-flattened dispersion variation of ± 0.03 ps/THz/cm at optimal design parameters. Besides, a number of other important wave-guiding properties including frequency dependence of the effective material loss (EML), confinement loss, and effective area are also investigated to assess the fiber's effectiveness as a terahertz waveguide.

Extremely low-loss, dispersion flattened porous-core photonic crystal fiber for terahertz regime

NASA Astrophysics Data System (ADS)

Islam, Saiful; Islam, Mohammad Rakibul; Faisal, Mohammad; Arefin, Abu Sayeed Muhammad Shamsul; Rahman, Hasan; Sultana, Jakeya; Rana, Sohel

2016-07-01

A porous-core octagonal photonic crystal fiber (PC-OPCF) with ultralow effective material loss (EML), high core power fraction, and ultra flattened dispersion is proposed for terahertz (THz) wave propagation. At an operating frequency of 1 THz and core diameter of 345 μm, simulation results display an extremely low EML of 0.047 cm-1, 49.1% power transmission through core air holes, decreased confinement loss with the increase of frequency, and dispersion variation of 0.15 ps/THz/cm. In addition, the proposed PCF can successfully operate in single-mode condition. All the simulations are performed with finite-element modeling package, COMSOL v4.2. The design can be fabricated using a stacking and drilling method. Thus, the proposed fiber has the potential of being an effective transmission medium of broadband THz waves.

Application of the GNU Radio platform in the multistatic radar

NASA Astrophysics Data System (ADS)

Szlachetko, Boguslaw; Lewandowski, Andrzej

2009-06-01

This document presents the application of the Software Defined Radio-based platform in the multistatic radar. This platform consists of four-sensor linear antenna, Universal Software Radio Peripheral (USRP) hardware (radio frequency frontend) and GNU-Radio PC software. The paper provides information about architecture of digital signal processing performed by USRP's FPGA (digital down converting blocks) and PC host (implementation of the multichannel digital beamforming). The preliminary results of the signal recording performed by our experimental platform are presented.

Clustering of immunological, metabolic and genetic features in latent autoimmune diabetes in adults: evidence from principal component analysis.

PubMed

Pes, Giovanni Mario; Delitala, Alessandro Palmerio; Errigo, Alessandra; Delitala, Giuseppe; Dore, Maria Pina

2016-06-01

Latent autoimmune diabetes in adults (LADA) which accounts for more than 10 % of all cases of diabetes is characterized by onset after age 30, absence of ketoacidosis, insulin independence for at least 6 months, and presence of circulating islet-cell antibodies. Its marked heterogeneity in clinical features and immunological markers suggests the existence of multiple mechanisms underlying its pathogenesis. The principal component (PC) analysis is a statistical approach used for finding patterns in data of high dimension. In this study the PC analysis was applied to a set of variables from a cohort of Sardinian LADA patients to identify a smaller number of latent patterns. A list of 11 variables including clinical (gender, BMI, lipid profile, systolic and diastolic blood pressure and insulin-free time period), immunological (anti-GAD65, anti-IA-2 and anti-TPO antibody titers) and genetic features (predisposing gene variants previously identified as risk factors for autoimmune diabetes) retrieved from clinical records of 238 LADA patients referred to the Internal Medicine Unit of University of Sassari, Italy, were analyzed by PC analysis. The predictive value of each PC on the further development of insulin dependence was evaluated using Kaplan-Meier curves. Overall 4 clusters were identified by PC analysis. In component PC-1, the dominant variables were: BMI, triglycerides, systolic and diastolic blood pressure and duration of insulin-free time period; in PC-2: genetic variables such as Class II HLA, CTLA-4 as well as anti-GAD65, anti-IA-2 and anti-TPO antibody titers, and the insulin-free time period predominated; in PC-3: gender and triglycerides; and in PC-4: total cholesterol. These components explained 18, 15, 12, and 12 %, respectively, of the total variance in the LADA cohort. The predictive power of insulin dependence of the four components was different. PC-2 (characterized mostly by high antibody titers and presence of predisposing genetic markers) showed a faster beta-cells failure and PC-3 (characterized mostly by gender and high triglycerides) and PC-4 (high cholesterol) showed a slower beta-cells failure. PC-1 (including dislipidemia and other metabolic dysfunctions), showed a mild beta-cells failure. In conclusion variable clustering might be consistent with different pathogenic pathways and/or distinct immune mechanisms in LADA and could potentially help physicians improve the clinical management of these patients.

Multiple polymer architectures of human Polyhomeotic homolog 3 (PHC3) SAM

PubMed Central

Nanyes, David R.; Junco, Sarah E.; Taylor, Alexander B.; Robinson, Angela K.; Patterson, Nicolle L.; Shivarajpur, Ambika; Halloran, Jonathan; Hale, Seth M.; Kaur, Yogeet; Hart, P. John; Kim, Chongwoo A.

2014-01-01

The self-association of sterile alpha motifs (SAMs) into a helical polymer architecture is a critical functional component of many different and diverse array of proteins. For the Drosophila Polycomb group (PcG) protein Polyhomeotic (Ph), its SAM polymerization serves as the structural foundation to cluster multiple PcG complexes, helping to maintain a silenced chromatin state. Ph SAM shares 64% sequence identity with its human ortholog, PHC3 SAM, and both SAMs polymerize. However, in the context of their larger protein regions, PHC3 SAM forms longer polymers compared to Ph SAM. Motivated to establish the precise structural basis for the differences, if any, between Ph and PHC3 SAM, we determined the crystal structure of the PHC3 SAM polymer. PHC3 SAM utilizes the same SAM-SAM interaction as the Ph SAM six-fold repeat polymer. Yet, PHC3 SAM polymerizes utilizing just five SAMs per turn of the helical polymer rather than the typical six per turn observed for all SAM polymers reported to date. Structural analysis suggested that malleability of the PHC3 SAM would allow formation of not just the five-fold repeat structure but possibly others. Indeed, a second PHC3 SAM polymer in a different crystal form forms a six-fold repeat polymer. These results suggest that the polymers formed by PHC3 SAM, and likely others, are quite dynamic. The functional consequence of the variable PHC3 SAM polymers may be to create different chromatin architectures. PMID:25044168

Evidence for Exotic Hadron Contributions to Λb0→J /ψ p π- Decays

NASA Astrophysics Data System (ADS)

Aaij, R.; Abellán Beteta, C.; Adeva, B.; Adinolfi, M.; Ajaltouni, Z.; Akar, S.; Albrecht, J.; Alessio, F.; Alexander, M.; Ali, S.; Alkhazov, G.; Alvarez Cartelle, P.; Alves, A. A.; Amato, S.; Amerio, S.; Amhis, Y.; An, L.; Anderlini, L.; Andreassi, G.; Andreotti, M.; Andrews, J. E.; Appleby, R. B.; Aquines Gutierrez, O.; Archilli, F.; d'Argent, P.; Arnau Romeu, J.; Artamonov, A.; Artuso, M.; Aslanides, E.; Auriemma, G.; Baalouch, M.; Bachmann, S.; Back, J. J.; Badalov, A.; Baesso, C.; Baldini, W.; Barlow, R. J.; Barschel, C.; Barsuk, S.; Barter, W.; Batozskaya, V.; Battista, V.; Bay, A.; Beaucourt, L.; Beddow, J.; Bedeschi, F.; Bediaga, I.; Bel, L. J.; Bellee, V.; Belloli, N.; Belous, K.; Belyaev, I.; Ben-Haim, E.; Bencivenni, G.; Benson, S.; Benton, J.; Berezhnoy, A.; Bernet, R.; Bertolin, A.; Bettler, M.-O.; van Beuzekom, M.; Bifani, S.; Billoir, P.; Bird, T.; Birnkraut, A.; Bitadze, A.; Bizzeti, A.; Blake, T.; Blanc, F.; Blouw, J.; Blusk, S.; Bocci, V.; Boettcher, T.; Bondar, A.; Bondar, N.; Bonivento, W.; Borghi, S.; Borisyak, M.; Borsato, M.; Bossu, F.; Boubdir, M.; Bowcock, T. J. V.; Bowen, E.; Bozzi, C.; Braun, S.; Britsch, M.; Britton, T.; Brodzicka, J.; Buchanan, E.; Burr, C.; Bursche, A.; Buytaert, J.; Cadeddu, S.; Calabrese, R.; Calvi, M.; Calvo Gomez, M.; Campana, P.; Campora Perez, D.; Capriotti, L.; Carbone, A.; Carboni, G.; Cardinale, R.; Cardini, A.; Carniti, P.; Carson, L.; Carvalho Akiba, K.; Casse, G.; Cassina, L.; Castillo Garcia, L.; Cattaneo, M.; Cauet, Ch.; Cavallero, G.; Cenci, R.; Charles, M.; Charpentier, Ph.; Chatzikonstantinidis, G.; Chefdeville, M.; Chen, S.; Cheung, S.-F.; Chobanova, V.; Chrzaszcz, M.; Cid Vidal, X.; Ciezarek, G.; Clarke, P. E. L.; Clemencic, M.; Cliff, H. V.; Closier, J.; Coco, V.; Cogan, J.; Cogneras, E.; Cogoni, V.; Cojocariu, L.; Collazuol, G.; Collins, P.; Comerma-Montells, A.; Contu, A.; Cook, A.; Coquereau, S.; Corti, G.; Corvo, M.; Costa Sobral, C. M.; Couturier, B.; Cowan, G. A.; Craik, D. C.; Crocombe, A.; Cruz Torres, M.; Cunliffe, S.; Currie, R.; D'Ambrosio, C.; Dall'Occo, E.; Dalseno, J.; David, P. N. Y.; Davis, A.; De Aguiar Francisco, O.; De Bruyn, K.; De Capua, S.; De Cian, M.; De Miranda, J. M.; De Paula, L.; De Simone, P.; Dean, C.-T.; Decamp, D.; Deckenhoff, M.; Del Buono, L.; Demmer, M.; Derkach, D.; Deschamps, O.; Dettori, F.; Dey, B.; Di Canto, A.; Dijkstra, H.; Dordei, F.; Dorigo, M.; Dosil Suárez, A.; Dovbnya, A.; Dreimanis, K.; Dufour, L.; Dujany, G.; Dungs, K.; Durante, P.; Dzhelyadin, R.; Dziurda, A.; Dzyuba, A.; Déléage, N.; Easo, S.; Egede, U.; Egorychev, V.; Eidelman, S.; Eisenhardt, S.; Eitschberger, U.; Ekelhof, R.; Eklund, L.; Elsasser, Ch.; Ely, S.; Esen, S.; Evans, H. M.; Evans, T.; Falabella, A.; Farley, N.; Farry, S.; Fay, R.; Ferguson, D.; Fernandez Albor, V.; Ferrari, F.; Ferreira Rodrigues, F.; Ferro-Luzzi, M.; Filippov, S.; Fiore, M.; Fiorini, M.; Firlej, M.; Fitzpatrick, C.; Fiutowski, T.; Fleuret, F.; Fohl, K.; Fontana, M.; Fontanelli, F.; Forshaw, D. C.; Forty, R.; Frank, M.; Frei, C.; Frosini, M.; Fu, J.; Furfaro, E.; Färber, C.; Gallas Torreira, A.; Galli, D.; Gallorini, S.; Gambetta, S.; Gandelman, M.; Gandini, P.; Gao, Y.; García Pardiñas, J.; Garra Tico, J.; Garrido, L.; Garsed, P. J.; Gascon, D.; Gaspar, C.; Gavardi, L.; Gazzoni, G.; Gerick, D.; Gersabeck, E.; Gersabeck, M.; Gershon, T.; Ghez, Ph.; Gianı, S.; Gibson, V.; Girard, O. G.; Giubega, L.; Gizdov, K.; Gligorov, V. V.; Golubkov, D.; Golutvin, A.; Gomes, A.; Gorelov, I. V.; Gotti, C.; Grabalosa Gándara, M.; Graciani Diaz, R.; Granado Cardoso, L. A.; Graugés, E.; Graverini, E.; Graziani, G.; Grecu, A.; Griffith, P.; Grillo, L.; Gruberg Cazon, B. R.; Grünberg, O.; Gushchin, E.; Guz, Yu.; Gys, T.; Göbel, C.; Hadavizadeh, T.; Hadjivasiliou, C.; Haefeli, G.; Haen, C.; Haines, S. C.; Hall, S.; Hamilton, B.; Han, X.; Hansmann-Menzemer, S.; Harnew, N.; Harnew, S. T.; Harrison, J.; He, J.; Head, T.; Heister, A.; Hennessy, K.; Henrard, P.; Henry, L.; Hernando Morata, J. A.; van Herwijnen, E.; Heß, M.; Hicheur, A.; Hill, D.; Hombach, C.; Hulsbergen, W.; Humair, T.; Hushchyn, M.; Hussain, N.; Hutchcroft, D.; Idzik, M.; Ilten, P.; Jacobsson, R.; Jaeger, A.; Jalocha, J.; Jans, E.; Jawahery, A.; John, M.; Johnson, D.; Jones, C. R.; Joram, C.; Jost, B.; Jurik, N.; Kandybei, S.; Kanso, W.; Karacson, M.; Kariuki, J. M.; Karodia, S.; Kecke, M.; Kelsey, M.; Kenyon, I. R.; Kenzie, M.; Ketel, T.; Khairullin, E.; Khanji, B.; Khurewathanakul, C.; Kirn, T.; Klaver, S.; Klimaszewski, K.; Koliiev, S.; Kolpin, M.; Komarov, I.; Koopman, R. F.; Koppenburg, P.; Kozachuk, A.; Kozeiha, M.; Kravchuk, L.; Kreplin, K.; Kreps, M.; Krokovny, P.; Kruse, F.; Krzemien, W.; Kucewicz, W.; Kucharczyk, M.; Kudryavtsev, V.; Kuonen, A. K.; Kurek, K.; Kvaratskheliya, T.; Lacarrere, D.; Lafferty, G.; Lai, A.; Lambert, D.; Lanfranchi, G.; Langenbruch, C.; Langhans, B.; Latham, T.; Lazzeroni, C.; Le Gac, R.; van Leerdam, J.; Lees, J.-P.; Leflat, A.; Lefrançois, J.; Lefèvre, R.; Lemaitre, F.; Lemos Cid, E.; Leroy, O.; Lesiak, T.; Leverington, B.; Li, Y.; Likhomanenko, T.; Lindner, R.; Linn, C.; Lionetto, F.; Liu, B.; Liu, X.; Loh, D.; Longstaff, I.; Lopes, J. H.; Lucchesi, D.; Lucio Martinez, M.; Luo, H.; Lupato, A.; Luppi, E.; Lupton, O.; Lusiani, A.; Lyu, X.; Machefert, F.; Maciuc, F.; Maev, O.; Maguire, K.; Malde, S.; Malinin, A.; Maltsev, T.; Manca, G.; Mancinelli, G.; Manning, P.; Maratas, J.; Marchand, J. F.; Marconi, U.; Marin Benito, C.; Marino, P.; Marks, J.; Martellotti, G.; Martin, M.; Martinelli, M.; Martinez Santos, D.; Martinez Vidal, F.; Martins Tostes, D.; Massacrier, L. M.; Massafferri, A.; Matev, R.; Mathad, A.; Mathe, Z.; Matteuzzi, C.; Mauri, A.; Maurin, B.; Mazurov, A.; McCann, M.; McCarthy, J.; McNab, A.; McNulty, R.; Meadows, B.; Meier, F.; Meissner, M.; Melnychuk, D.; Merk, M.; Michielin, E.; Milanes, D. A.; Minard, M.-N.; Mitzel, D. S.; Molina Rodriguez, J.; Monroy, I. A.; Monteil, S.; Morandin, M.; Morawski, P.; Mordà, A.; Morello, M. J.; Moron, J.; Morris, A. B.; Mountain, R.; Muheim, F.; Mulder, M.; Mussini, M.; Müller, D.; Müller, J.; Müller, K.; Müller, V.; Naik, P.; Nakada, T.; Nandakumar, R.; Nandi, A.; Nasteva, I.; Needham, M.; Neri, N.; Neubert, S.; Neufeld, N.; Neuner, M.; Nguyen, A. D.; Nguyen-Mau, C.; Niess, V.; Nieswand, S.; Niet, R.; Nikitin, N.; Nikodem, T.; Novoselov, A.; O'Hanlon, D. P.; Oblakowska-Mucha, A.; Obraztsov, V.; Ogilvy, S.; Okhrimenko, O.; Oldeman, R.; Onderwater, C. J. G.; Otalora Goicochea, J. M.; Otto, A.; Owen, P.; Oyanguren, A.; Pais, P. R.; Palano, A.; Palombo, F.; Palutan, M.; Panman, J.; Papanestis, A.; Pappagallo, M.; Pappalardo, L. L.; Pappenheimer, C.; Parker, W.; Parkes, C.; Passaleva, G.; Patel, G. D.; Patel, M.; Patrignani, C.; Pearce, A.; Pellegrino, A.; Penso, G.; Pepe Altarelli, M.; Perazzini, S.; Perret, P.; Pescatore, L.; Petridis, K.; Petrolini, A.; Petrov, A.; Petruzzo, M.; Picatoste Olloqui, E.; Pietrzyk, B.; Pikies, M.; Pinci, D.; Pistone, A.; Piucci, A.; Playfer, S.; Plo Casasus, M.; Poikela, T.; Polci, F.; Poluektov, A.; Polyakov, I.; Polycarpo, E.; Pomery, G. J.; Popov, A.; Popov, D.; Popovici, B.; Potterat, C.; Price, E.; Price, J. D.; Prisciandaro, J.; Pritchard, A.; Prouve, C.; Pugatch, V.; Puig Navarro, A.; Punzi, G.; Qian, W.; Quagliani, R.; Rachwal, B.; Rademacker, J. H.; Rama, M.; Ramos Pernas, M.; Rangel, M. S.; Raniuk, I.; Raven, G.; Redi, F.; Reichert, S.; dos Reis, A. C.; Remon Alepuz, C.; Renaudin, V.; Ricciardi, S.; Richards, S.; Rihl, M.; Rinnert, K.; Rives Molina, V.; Robbe, P.; Rodrigues, A. B.; Rodrigues, E.; Rodriguez Lopez, J. A.; Rodriguez Perez, P.; Rogozhnikov, A.; Roiser, S.; Romanovskiy, V.; Romero Vidal, A.; Ronayne, J. W.; Rotondo, M.; Ruf, T.; Ruiz Valls, P.; Saborido Silva, J. J.; Sadykhov, E.; Sagidova, N.; Saitta, B.; Salustino Guimaraes, V.; Sanchez Mayordomo, C.; Sanmartin Sedes, B.; Santacesaria, R.; Santamarina Rios, C.; Santimaria, M.; Santovetti, E.; Sarti, A.; Satriano, C.; Satta, A.; Saunders, D. M.; Savrina, D.; Schael, S.; Schiller, M.; Schindler, H.; Schlupp, M.; Schmelling, M.; Schmelzer, T.; Schmidt, B.; Schneider, O.; Schopper, A.; Schubiger, M.; Schune, M.-H.; Schwemmer, R.; Sciascia, B.; Sciubba, A.; Semennikov, A.; Sergi, A.; Serra, N.; Serrano, J.; Sestini, L.; Seyfert, P.; Shapkin, M.; Shapoval, I.; Shcheglov, Y.; Shears, T.; Shekhtman, L.; Shevchenko, V.; Shires, A.; Siddi, B. G.; Silva Coutinho, R.; Silva de Oliveira, L.; Simi, G.; Sirendi, M.; Skidmore, N.; Skwarnicki, T.; Smith, E.; Smith, I. T.; Smith, J.; Smith, M.; Snoek, H.; Sokoloff, M. D.; Soler, F. J. P.; Souza, D.; Souza De Paula, B.; Spaan, B.; Spradlin, P.; Sridharan, S.; Stagni, F.; Stahl, M.; Stahl, S.; Stefko, P.; Stefkova, S.; Steinkamp, O.; Stenyakin, O.; Stevenson, S.; Stoica, S.; Stone, S.; Storaci, B.; Stracka, S.; Straticiuc, M.; Straumann, U.; Sun, L.; Sutcliffe, W.; Swientek, K.; Syropoulos, V.; Szczekowski, M.; Szumlak, T.; T'Jampens, S.; Tayduganov, A.; Tekampe, T.; Tellarini, G.; Teubert, F.; Thomas, C.; Thomas, E.; van Tilburg, J.; Tisserand, V.; Tobin, M.; Tolk, S.; Tomassetti, L.; Tonelli, D.; Topp-Joergensen, S.; Toriello, F.; Tournefier, E.; Tourneur, S.; Trabelsi, K.; Traill, M.; Tran, M. T.; Tresch, M.; Trisovic, A.; Tsaregorodtsev, A.; Tsopelas, P.; Tully, A.; Tuning, N.; Ukleja, A.; Ustyuzhanin, A.; Uwer, U.; Vacca, C.; Vagnoni, V.; Valat, S.; Valenti, G.; Vallier, A.; Vazquez Gomez, R.; Vazquez Regueiro, P.; Vecchi, S.; van Veghel, M.; Velthuis, J. J.; Veltri, M.; Veneziano, G.; Venkateswaran, A.; Vesterinen, M.; Viaud, B.; Vieira, D.; Vieites Diaz, M.; Vilasis-Cardona, X.; Volkov, V.; Vollhardt, A.; Voneki, B.; Voong, D.; Vorobyev, A.; Vorobyev, V.; Voß, C.; de Vries, J. A.; Vázquez Sierra, C.; Waldi, R.; Wallace, C.; Wallace, R.; Walsh, J.; Wang, J.; Ward, D. R.; Wark, H. M.; Watson, N. K.; Websdale, D.; Weiden, A.; Whitehead, M.; Wicht, J.; Wilkinson, G.; Wilkinson, M.; Williams, M.; Williams, M. P.; Williams, M.; Williams, T.; Wilson, F. F.; Wimberley, J.; Wishahi, J.; Wislicki, W.; Witek, M.; Wormser, G.; Wotton, S. A.; Wraight, K.; Wright, S.; Wyllie, K.; Xie, Y.; Xu, Z.; Yang, Z.; Yin, H.; Yu, J.; Yuan, X.; Yushchenko, O.; Zangoli, M.; Zarebski, K. A.; Zavertyaev, M.; Zhang, L.; Zhang, Y.; Zhang, Y.; Zhelezov, A.; Zheng, Y.; Zhokhov, A.; Zhukov, V.; Zucchelli, S.; LHCb Collaboration

2016-08-01

A full amplitude analysis of Λb0→J /ψ p π- decays is performed with a data sample acquired with the LHCb detector from 7 and 8 TeV p p collisions, corresponding to an integrated luminosity of 3 fb-1. A significantly better description of the data is achieved when, in addition to the previously observed nucleon excitations N →p π-, either the Pc(4380 )+ and Pc(4450)+→J/ψp states, previously observed in Λb0→J /ψ p K- decays, or the Zc(4200)-→J /ψ π-state, previously reported in B0→J /ψ K+π- decays, or all three, are included in the amplitude models. The data support a model containing all three exotic states, with a significance of more than three standard deviations. Within uncertainties, the data are consistent with the Pc(4380)+ and Pc(4450)+ production rates expected from their previous observation taking account of Cabibbo suppression.

Spin-based diagnostic of nanostructure in copper phthalocyanine-C60 solar cell blends.

PubMed

Warner, Marc; Mauthoor, Soumaya; Felton, Solveig; Wu, Wei; Gardener, Jules A; Din, Salahud; Klose, Daniel; Morley, Gavin W; Stoneham, A Marshall; Fisher, Andrew J; Aeppli, Gabriel; Kay, Christopher W M; Heutz, Sandrine

2012-12-21

Nanostructure and molecular orientation play a crucial role in determining the functionality of organic thin films. In practical devices, such as organic solar cells consisting of donor-acceptor mixtures, crystallinity is poor and these qualities cannot be readily determined by conventional diffraction techniques, while common microscopy only reveals surface morphology. Using a simple nondestructive technique, namely, continuous-wave electron paramagnetic resonance spectroscopy, which exploits the well-understood angular dependence of the g-factor and hyperfine tensors, we show that in the solar cell blend of C(60) and copper phthalocyanine (CuPc)-for which X-ray diffraction gives no information-the CuPc, and by implication the C(60), molecules form nanoclusters, with the planes of the CuPc molecules oriented perpendicular to the film surface. This information demonstrates that the current nanostructure in CuPc:C(60) solar cells is far from optimal and suggests that their efficiency could be considerably increased by alternative film growth algorithms.

Cell membrane-inspired polymeric micelles as carriers for drug delivery.

PubMed

Liu, Gongyan; Luo, Quanqing; Gao, Haiqi; Chen, Yuan; Wei, Xing; Dai, Hong; Zhang, Zongcai; Ji, Jian

2015-03-01

In cancer therapy, surface engineering of drug delivery systems plays an essential role in their colloidal stability, biocompatibility and prolonged blood circulation. Inspired by the cell membrane consisting of phospholipids and glycolipids, a zwitterionic phosphorylcholine functionalized chitosan oligosaccharide (PC-CSO) was first synthesized to mimic the hydrophilic head groups of those amphipathic lipids. Then hydrophobic stearic acid (SA) similar to lipid fatty acids was grafted onto PC-CSO to form amphiphilic PC-CSO-SA copolymers. Cell membrane-mimetic micelles with a zwitterionic surface and a hydrophobic SA core were prepared by the self-assembly of PC-CSO-SA copolymers, showing excellent stability under extreme conditions including protein containing media, high salt content or a wide pH range. Doxorubicin (DOX) was successfully entrapped into polymeric micelles through the hydrophobic interaction between DOX and SA segments. After fast internalization by cancer cells, sustained drug release from micelles to the cytoplasm and nucleus was achieved. This result suggests that these biomimetic polymeric micelles may be promising drug delivery systems in cancer therapy.

Evidence for Exotic Hadron Contributions to Λ_{b}^{0}→J/ψpπ^{-} Decays.

PubMed

Aaij, R; Abellán Beteta, C; Adeva, B; Adinolfi, M; Ajaltouni, Z; Akar, S; Albrecht, J; Alessio, F; Alexander, M; Ali, S; Alkhazov, G; Alvarez Cartelle, P; Alves, A A; Amato, S; Amerio, S; Amhis, Y; An, L; Anderlini, L; Andreassi, G; Andreotti, M; Andrews, J E; Appleby, R B; Aquines Gutierrez, O; Archilli, F; d'Argent, P; Arnau Romeu, J; Artamonov, A; Artuso, M; Aslanides, E; Auriemma, G; Baalouch, M; Bachmann, S; Back, J J; Badalov, A; Baesso, C; Baldini, W; Barlow, R J; Barschel, C; Barsuk, S; Barter, W; Batozskaya, V; Battista, V; Bay, A; Beaucourt, L; Beddow, J; Bedeschi, F; Bediaga, I; Bel, L J; Bellee, V; Belloli, N; Belous, K; Belyaev, I; Ben-Haim, E; Bencivenni, G; Benson, S; Benton, J; Berezhnoy, A; Bernet, R; Bertolin, A; Bettler, M-O; van Beuzekom, M; Bifani, S; Billoir, P; Bird, T; Birnkraut, A; Bitadze, A; Bizzeti, A; Blake, T; Blanc, F; Blouw, J; Blusk, S; Bocci, V; Boettcher, T; Bondar, A; Bondar, N; Bonivento, W; Borghi, S; Borisyak, M; Borsato, M; Bossu, F; Boubdir, M; Bowcock, T J V; Bowen, E; Bozzi, C; Braun, S; Britsch, M; Britton, T; Brodzicka, J; Buchanan, E; Burr, C; Bursche, A; Buytaert, J; Cadeddu, S; Calabrese, R; Calvi, M; Calvo Gomez, M; Campana, P; Campora Perez, D; Capriotti, L; Carbone, A; Carboni, G; Cardinale, R; Cardini, A; Carniti, P; Carson, L; Carvalho Akiba, K; Casse, G; Cassina, L; Castillo Garcia, L; Cattaneo, M; Cauet, Ch; Cavallero, G; Cenci, R; Charles, M; Charpentier, Ph; Chatzikonstantinidis, G; Chefdeville, M; Chen, S; Cheung, S-F; Chobanova, V; Chrzaszcz, M; Cid Vidal, X; Ciezarek, G; Clarke, P E L; Clemencic, M; Cliff, H V; Closier, J; Coco, V; Cogan, J; Cogneras, E; Cogoni, V; Cojocariu, L; Collazuol, G; Collins, P; Comerma-Montells, A; Contu, A; Cook, A; Coquereau, S; Corti, G; Corvo, M; Costa Sobral, C M; Couturier, B; Cowan, G A; Craik, D C; Crocombe, A; Cruz Torres, M; Cunliffe, S; Currie, R; D'Ambrosio, C; Dall'Occo, E; Dalseno, J; David, P N Y; Davis, A; De Aguiar Francisco, O; De Bruyn, K; De Capua, S; De Cian, M; De Miranda, J M; De Paula, L; De Simone, P; Dean, C-T; Decamp, D; Deckenhoff, M; Del Buono, L; Demmer, M; Derkach, D; Deschamps, O; Dettori, F; Dey, B; Di Canto, A; Dijkstra, H; Dordei, F; Dorigo, M; Dosil Suárez, A; Dovbnya, A; Dreimanis, K; Dufour, L; Dujany, G; Dungs, K; Durante, P; Dzhelyadin, R; Dziurda, A; Dzyuba, A; Déléage, N; Easo, S; Egede, U; Egorychev, V; Eidelman, S; Eisenhardt, S; Eitschberger, U; Ekelhof, R; Eklund, L; Elsasser, Ch; Ely, S; Esen, S; Evans, H M; Evans, T; Falabella, A; Farley, N; Farry, S; Fay, R; Ferguson, D; Fernandez Albor, V; Ferrari, F; Ferreira Rodrigues, F; Ferro-Luzzi, M; Filippov, S; Fiore, M; Fiorini, M; Firlej, M; Fitzpatrick, C; Fiutowski, T; Fleuret, F; Fohl, K; Fontana, M; Fontanelli, F; Forshaw, D C; Forty, R; Frank, M; Frei, C; Frosini, M; Fu, J; Furfaro, E; Färber, C; Gallas Torreira, A; Galli, D; Gallorini, S; Gambetta, S; Gandelman, M; Gandini, P; Gao, Y; García Pardiñas, J; Garra Tico, J; Garrido, L; Garsed, P J; Gascon, D; Gaspar, C; Gavardi, L; Gazzoni, G; Gerick, D; Gersabeck, E; Gersabeck, M; Gershon, T; Ghez, Ph; Gianì, S; Gibson, V; Girard, O G; Giubega, L; Gizdov, K; Gligorov, V V; Golubkov, D; Golutvin, A; Gomes, A; Gorelov, I V; Gotti, C; Grabalosa Gándara, M; Graciani Diaz, R; Granado Cardoso, L A; Graugés, E; Graverini, E; Graziani, G; Grecu, A; Griffith, P; Grillo, L; Gruberg Cazon, B R; Grünberg, O; Gushchin, E; Guz, Yu; Gys, T; Göbel, C; Hadavizadeh, T; Hadjivasiliou, C; Haefeli, G; Haen, C; Haines, S C; Hall, S; Hamilton, B; Han, X; Hansmann-Menzemer, S; Harnew, N; Harnew, S T; Harrison, J; He, J; Head, T; Heister, A; Hennessy, K; Henrard, P; Henry, L; Hernando Morata, J A; van Herwijnen, E; Heß, M; Hicheur, A; Hill, D; Hombach, C; Hulsbergen, W; Humair, T; Hushchyn, M; Hussain, N; Hutchcroft, D; Idzik, M; Ilten, P; Jacobsson, R; Jaeger, A; Jalocha, J; Jans, E; Jawahery, A; John, M; Johnson, D; Jones, C R; Joram, C; Jost, B; Jurik, N; Kandybei, S; Kanso, W; Karacson, M; Kariuki, J M; Karodia, S; Kecke, M; Kelsey, M; Kenyon, I R; Kenzie, M; Ketel, T; Khairullin, E; Khanji, B; Khurewathanakul, C; Kirn, T; Klaver, S; Klimaszewski, K; Koliiev, S; Kolpin, M; Komarov, I; Koopman, R F; Koppenburg, P; Kozachuk, A; Kozeiha, M; Kravchuk, L; Kreplin, K; Kreps, M; Krokovny, P; Kruse, F; Krzemien, W; Kucewicz, W; Kucharczyk, M; Kudryavtsev, V; Kuonen, A K; Kurek, K; Kvaratskheliya, T; Lacarrere, D; Lafferty, G; Lai, A; Lambert, D; Lanfranchi, G; Langenbruch, C; Langhans, B; Latham, T; Lazzeroni, C; Le Gac, R; van Leerdam, J; Lees, J-P; Leflat, A; Lefrançois, J; Lefèvre, R; Lemaitre, F; Lemos Cid, E; Leroy, O; Lesiak, T; Leverington, B; Li, Y; Likhomanenko, T; Lindner, R; Linn, C; Lionetto, F; Liu, B; Liu, X; Loh, D; Longstaff, I; Lopes, J H; Lucchesi, D; Lucio Martinez, M; Luo, H; Lupato, A; Luppi, E; Lupton, O; Lusiani, A; Lyu, X; Machefert, F; Maciuc, F; Maev, O; Maguire, K; Malde, S; Malinin, A; Maltsev, T; Manca, G; Mancinelli, G; Manning, P; Maratas, J; Marchand, J F; Marconi, U; Marin Benito, C; Marino, P; Marks, J; Martellotti, G; Martin, M; Martinelli, M; Martinez Santos, D; Martinez Vidal, F; Martins Tostes, D; Massacrier, L M; Massafferri, A; Matev, R; Mathad, A; Mathe, Z; Matteuzzi, C; Mauri, A; Maurin, B; Mazurov, A; McCann, M; McCarthy, J; McNab, A; McNulty, R; Meadows, B; Meier, F; Meissner, M; Melnychuk, D; Merk, M; Michielin, E; Milanes, D A; Minard, M-N; Mitzel, D S; Molina Rodriguez, J; Monroy, I A; Monteil, S; Morandin, M; Morawski, P; Mordà, A; Morello, M J; Moron, J; Morris, A B; Mountain, R; Muheim, F; Mulder, M; Mussini, M; Müller, D; Müller, J; Müller, K; Müller, V; Naik, P; Nakada, T; Nandakumar, R; Nandi, A; Nasteva, I; Needham, M; Neri, N; Neubert, S; Neufeld, N; Neuner, M; Nguyen, A D; Nguyen-Mau, C; Niess, V; Nieswand, S; Niet, R; Nikitin, N; Nikodem, T; Novoselov, A; O'Hanlon, D P; Oblakowska-Mucha, A; Obraztsov, V; Ogilvy, S; Okhrimenko, O; Oldeman, R; Onderwater, C J G; Otalora Goicochea, J M; Otto, A; Owen, P; Oyanguren, A; Pais, P R; Palano, A; Palombo, F; Palutan, M; Panman, J; Papanestis, A; Pappagallo, M; Pappalardo, L L; Pappenheimer, C; Parker, W; Parkes, C; Passaleva, G; Patel, G D; Patel, M; Patrignani, C; Pearce, A; Pellegrino, A; Penso, G; Pepe Altarelli, M; Perazzini, S; Perret, P; Pescatore, L; Petridis, K; Petrolini, A; Petrov, A; Petruzzo, M; Picatoste Olloqui, E; Pietrzyk, B; Pikies, M; Pinci, D; Pistone, A; Piucci, A; Playfer, S; Plo Casasus, M; Poikela, T; Polci, F; Poluektov, A; Polyakov, I; Polycarpo, E; Pomery, G J; Popov, A; Popov, D; Popovici, B; Potterat, C; Price, E; Price, J D; Prisciandaro, J; Pritchard, A; Prouve, C; Pugatch, V; Puig Navarro, A; Punzi, G; Qian, W; Quagliani, R; Rachwal, B; Rademacker, J H; Rama, M; Ramos Pernas, M; Rangel, M S; Raniuk, I; Raven, G; Redi, F; Reichert, S; Dos Reis, A C; Remon Alepuz, C; Renaudin, V; Ricciardi, S; Richards, S; Rihl, M; Rinnert, K; Rives Molina, V; Robbe, P; Rodrigues, A B; Rodrigues, E; Rodriguez Lopez, J A; Rodriguez Perez, P; Rogozhnikov, A; Roiser, S; Romanovskiy, V; Romero Vidal, A; Ronayne, J W; Rotondo, M; Ruf, T; Ruiz Valls, P; Saborido Silva, J J; Sadykhov, E; Sagidova, N; Saitta, B; Salustino Guimaraes, V; Sanchez Mayordomo, C; Sanmartin Sedes, B; Santacesaria, R; Santamarina Rios, C; Santimaria, M; Santovetti, E; Sarti, A; Satriano, C; Satta, A; Saunders, D M; Savrina, D; Schael, S; Schiller, M; Schindler, H; Schlupp, M; Schmelling, M; Schmelzer, T; Schmidt, B; Schneider, O; Schopper, A; Schubiger, M; Schune, M-H; Schwemmer, R; Sciascia, B; Sciubba, A; Semennikov, A; Sergi, A; Serra, N; Serrano, J; Sestini, L; Seyfert, P; Shapkin, M; Shapoval, I; Shcheglov, Y; Shears, T; Shekhtman, L; Shevchenko, V; Shires, A; Siddi, B G; Silva Coutinho, R; Silva de Oliveira, L; Simi, G; Sirendi, M; Skidmore, N; Skwarnicki, T; Smith, E; Smith, I T; Smith, J; Smith, M; Snoek, H; Sokoloff, M D; Soler, F J P; Souza, D; Souza De Paula, B; Spaan, B; Spradlin, P; Sridharan, S; Stagni, F; Stahl, M; Stahl, S; Stefko, P; Stefkova, S; Steinkamp, O; Stenyakin, O; Stevenson, S; Stoica, S; Stone, S; Storaci, B; Stracka, S; Straticiuc, M; Straumann, U; Sun, L; Sutcliffe, W; Swientek, K; Syropoulos, V; Szczekowski, M; Szumlak, T; T'Jampens, S; Tayduganov, A; Tekampe, T; Tellarini, G; Teubert, F; Thomas, C; Thomas, E; van Tilburg, J; Tisserand, V; Tobin, M; Tolk, S; Tomassetti, L; Tonelli, D; Topp-Joergensen, S; Toriello, F; Tournefier, E; Tourneur, S; Trabelsi, K; Traill, M; Tran, M T; Tresch, M; Trisovic, A; Tsaregorodtsev, A; Tsopelas, P; Tully, A; Tuning, N; Ukleja, A; Ustyuzhanin, A; Uwer, U; Vacca, C; Vagnoni, V; Valat, S; Valenti, G; Vallier, A; Vazquez Gomez, R; Vazquez Regueiro, P; Vecchi, S; van Veghel, M; Velthuis, J J; Veltri, M; Veneziano, G; Venkateswaran, A; Vesterinen, M; Viaud, B; Vieira, D; Vieites Diaz, M; Vilasis-Cardona, X; Volkov, V; Vollhardt, A; Voneki, B; Voong, D; Vorobyev, A; Vorobyev, V; Voß, C; de Vries, J A; Vázquez Sierra, C; Waldi, R; Wallace, C; Wallace, R; Walsh, J; Wang, J; Ward, D R; Wark, H M; Watson, N K; Websdale, D; Weiden, A; Whitehead, M; Wicht, J; Wilkinson, G; Wilkinson, M; Williams, M; Williams, M P; Williams, M; Williams, T; Wilson, F F; Wimberley, J; Wishahi, J; Wislicki, W; Witek, M; Wormser, G; Wotton, S A; Wraight, K; Wright, S; Wyllie, K; Xie, Y; Xu, Z; Yang, Z; Yin, H; Yu, J; Yuan, X; Yushchenko, O; Zangoli, M; Zarebski, K A; Zavertyaev, M; Zhang, L; Zhang, Y; Zhang, Y; Zhelezov, A; Zheng, Y; Zhokhov, A; Zhukov, V; Zucchelli, S

2016-08-19

A full amplitude analysis of Λ_{b}^{0}→J/ψpπ^{-} decays is performed with a data sample acquired with the LHCb detector from 7 and 8 TeV pp collisions, corresponding to an integrated luminosity of 3  fb^{-1}. A significantly better description of the data is achieved when, in addition to the previously observed nucleon excitations N→pπ^{-}, either the P_{c}(4380)^{+} and P_{c}(4450)^{+}→J/ψp states, previously observed in Λ_{b}^{0}→J/ψpK^{-} decays, or the Z_{c}(4200)^{-}→J/ψπ^{-} state, previously reported in B^{0}→J/ψK^{+}π^{-} decays, or all three, are included in the amplitude models. The data support a model containing all three exotic states, with a significance of more than three standard deviations. Within uncertainties, the data are consistent with the P_{c}(4380)^{+} and P_{c}(4450)^{+} production rates expected from their previous observation taking account of Cabibbo suppression.

Pc-based car license plate reading

NASA Astrophysics Data System (ADS)

Tanabe, Katsuyoshi; Marubayashi, Eisaku; Kawashima, Harumi; Nakanishi, Tadashi; Shio, Akio

1994-03-01

A PC-based car license plate recognition system has been developed. The system recognizes Chinese characters and Japanese phonetic hiragana characters as well as six digits on Japanese license plates. The system consists of a CCD camera, vehicle sensors, a strobe unit, a monitoring center, and an i486-based PC. The PC includes in its extension slots: a vehicle detector board, a strobe emitter board, and an image grabber board. When a passing vehicle is detected by the vehicle sensors, the strobe emits a pulse of light. The light pulse is synchronized with the time the vehicle image is frozen on an image grabber board. The recognition process is composed of three steps: image thresholding, character region extraction, and matching-based character recognition. The recognition software can handle obscured characters. Experimental results for hundreds of outdoor images showed high recognition performance within relatively short performance times. The results confirmed that the system is applicable to a wide variety of applications such as automatic vehicle identification and travel time measurement.

Post-contrast acute kidney injury. Part 2: risk stratification, role of hydration and other prophylactic measures, patients taking metformin and chronic dialysis patients : Recommendations for updated ESUR Contrast Medium Safety Committee guidelines.

PubMed

van der Molen, Aart J; Reimer, Peter; Dekkers, Ilona A; Bongartz, Georg; Bellin, Marie-France; Bertolotto, Michele; Clement, Olivier; Heinz-Peer, Gertraud; Stacul, Fulvio; Webb, Judith A W; Thomsen, Henrik S

2018-07-01

The Contrast Media Safety Committee (CMSC) of the European Society of Urogenital Radiology (ESUR) has updated its 2011 guidelines on the prevention of post-contrast acute kidney injury (PC-AKI). The results of the literature review and the recommendations based on it, which were used to prepare the new guidelines, are presented in two papers. AREAS COVERED IN PART 2: Topics reviewed include stratification of PC-AKI risk, the need to withdraw nephrotoxic medication, PC-AKI prophylaxis with hydration or drugs, the use of metformin in diabetic patients receiving contrast medium and the need to alter dialysis schedules in patients receiving contrast medium. • In CKD, hydration reduces the PC-AKI risk • Intravenous normal saline and intravenous sodium bicarbonate provide equally effective prophylaxis • No drugs have been consistently shown to reduce the risk of PC-AKI • Stop metformin from the time of contrast medium administration if eGFR < 30 ml/min/1.73 m 2 • Dialysis schedules need not change when intravascular contrast medium is given.

Molecular Drivers of Pancreatic Cancer Pathogenesis: Looking Inward to Move Forward

PubMed Central

Khan, Mohammad Aslam; Azim, Shafquat; Zubair, Haseeb; Bhardwaj, Arun; Patel, Girijesh Kumar; Khushman, Moh’d; Singh, Seema; Singh, Ajay Pratap

2017-01-01

Pancreatic cancer (PC) continues to rank among the most lethal cancers. The consistent increase in incidence and mortality has made it the seventh leading cause of cancer-associated deaths globally and the third in the United States. The biggest challenge in combating PC is our insufficient understanding of the molecular mechanism(s) underlying its complex biology. Studies during the last several years have helped identify several putative factors and events, both genetic and epigenetic, as well as some deregulated signaling pathways, with implications in PC onset and progression. In this review article, we make an effort to summarize our current understanding of molecular and cellular events involved in the pathogenesis of pancreatic malignancy. Specifically, we provide up-to-date information on the genetic and epigenetic changes that occur during the initiation and progression of PC and their functional involvement in the pathogenic processes. We also discuss the impact of the tumor microenvironment on the molecular landscape of PC and its role in aggressive disease progression. It is envisioned that a better understanding of these molecular factors and the mechanisms of their actions can help unravel novel diagnostic and prognostic biomarkers and can also be exploited for future targeted therapies. PMID:28383487

Cusp-related Pc3-5 Wave Activity

NASA Astrophysics Data System (ADS)

Pilipenko, V.; Engebretson, M. J.; Kozlovsky, A.; Belakhovsky, V.; Lessard, M.; Yeoman, T. K.

2009-12-01

Pc3-5 pulsations were found to be an ubiquitous element of dayside ULF wave activity at the cusp region. We examine observations of Pc3-5 wave activity by search coil and flux-gate magnetometers at three locations on Svalbard, covering geomagnetic latitudes 74o-76o. To identify the ionospheric projections of the cusp, we use the width of the return signal from the SuperDARN Finland radar covering the Svalbard archipelago. The ULF meridional spatial structure is examined using the amplitude-phase gradient technique. This analysis shows no specific mode conversion pattern near the cusp region. The amplitude gradient mainly has the same direction at all frequencies, and only during periods when the cusp is shifted to very high latitudes, the gradient may change sign. The phase delay is chaotic and does not show any consistent pattern. This behavior corresponds to the occurrence of a localized peak in the latitudinal distribution of Pc3-5 power, but not under the cusp proper as was previously thought, but about several degrees southward from the equatorward cusp boundary. We suppose that compressional Pc3 fluctuations leaking from the magnetosheath into the entry layer of the magnetosphere can modulate the precipitating electron fluxes, which produce the ground response.

A Novel Gas Sensor Transducer Based on Phthalocyanine Heterojunction Devices

PubMed Central

Muzikante, Inta; Parra, Vicente; Dobulans, Rorijs; Fonavs, Egils; Latvels, Janis; Bouvet, Marcel

2007-01-01

Experimental data concerning the changes in the current-voltage (I-V) performances of a molecular material-based heterojunction consisting of hexadecafluorinated nickel phthalocyanine (Ni(F16Pc)) and nickel phthalocyanine (NiPc), (Au|Ni(F16Pc)|NiPc|Al) are introduced as an unprecedented principle of transduction for gas sensing performances. The respective n- and p-type doped-insulator behaviors of the respective materials are supported, owing to the observed changes in surface potential (using the Kelvin probe method) after submission to electron donor (ammonia) and electron acceptor gases (ozone). On the other hand, the bilayer device exhibits strong variations in the built-in potential of the junction and in its rectification ratio. Moreover, large increases occur in forward and reverse currents in presence of ammonia vapors. These make possible a multimodal principle of detection controlled by a combined effect between the heterojunction and the NiPc|Al contact. Indeed, this metal/organic junction plays a critical role regarding the steady asymmetry of the I-V profiles during the device's doping even using high ammonia concentrations. This approach offers a more sophisticated alternative to the classically studied, but at times rather operation-limited, resistive gas sensors. PMID:28903274

Cell attachment properties of Portland cement-based endodontic materials: biological and methodological considerations.

PubMed

Ahmed, Hany Mohamed Aly; Luddin, Norhayati; Kannan, Thirumulu Ponnuraj; Mokhtar, Khairani Idah; Ahmad, Azlina

2014-10-01

The attachment and spreading of mammalian cells on endodontic biomaterials are an area of active research. The purpose of this review is to discuss the cell attachment properties of Portland cement (PC)-based materials by using scanning electron microscope (SEM). In addition, methodological aspects and technical challenges are discussed. A PubMed electronic search was conducted by using appropriate key words to identify the available investigations on the cell attachment properties of PC-based endodontic materials. After retrieving the full text of related articles, the cross citations were also identified. A total of 23 articles published between January 1993 and October 2013 were identified. This review summarizes the cell attachment properties of commercial and experimental PC-based materials on different cell cultures by using SEM. Methodological procedures, technical challenges, and relevance of SEM in determining the biological profile of PC-based materials are discussed. SEM observations demonstrate that commercial MTA formulations show favorable cell attachment properties, which is consistent with their successful clinical outcomes. The favorable cell attachment properties of PC and its modified formulations support its potential use as a substitute for mineral trioxide aggregate. However, researchers should carefully select cell types for their SEM investigations that would be in contact with the proposed PC-based combinations in the clinical situation. Despite being a technical challenge, SEM provides useful information on the cell attachment properties of PC-based materials; however, other assays for cell proliferation and viability are essential to come up with an accurate in vitro biological profile of any given PC-based formulation. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

The auditory comprehension changes over time after sport-related concussion can indicate multisensory processing dysfunctions.

PubMed

Białuńska, Anita; Salvatore, Anthony P

2017-12-01

Although science findings and treatment approaches of a concussion have changed in recent years, there continue to be challenges in understanding the nature of the post-concussion behavior. There is growing a body of evidence that some deficits can be related to an impaired auditory processing. To assess auditory comprehension changes over time following sport-related concussion (SRC) in young athletes. A prospective, repeated measures mixed-design was used. A sample of concussed athletes ( n  = 137) and the control group consisted of age-matched, non-concussed athletes ( n  = 143) were administered Subtest VIII of the Computerized-Revised Token Test (C-RTT). The 88 concussed athletes selected for final analysis (neither previous history of brain injury, neurological, psychiatric problems, nor auditory deficits) were evaluated after injury during three sessions (PC1, PC2, and PC3); controls were tested once. Between- and within-group comparisons using RMANOVA were performed on the C-RTT Efficiency Score (ES). ES of the SRC athletes group improved over consecutive testing sessions ( F  =   14.7, p  <   .001), while post-hoc analysis showed that PC1 results differed from PC2 and PC3 ( ts  ≥ 4.0, ps  < .001), but PC2 and PC3 C-RTT ES did not change statistically ( t  =   0.6, p =  .557). The SRC athletes demonstrated lower ES for all test session when compared to the control group ( ts  > 2.0, Ps <.01). Dysfunctional auditory comprehension performance following a concussion improved over time, but after the second testing session improved performance slowed, especially in terms of its timing. Yet, not only auditory processing but also sensorimotor integration and/or motor execution can be compromised after a concussion.

Characterization of Clostridium thermocellum (B8) secretome and purified cellulosomes for lignocellulosic biomass degradation.

PubMed

Osiro, Karen O; de Camargo, Brenda R; Satomi, Rachel; Hamann, Pedro Ricardo V; Silva, Jéssica Pinheiro; de Sousa, Marcelo Valle; Quirino, Betania F; Aquino, Elaine N; Felix, Carlos R; Murad, André Melro; Noronha, Eliane F

2017-02-01

The main goal of the present study was a complete proteomic characterization of total proteins eluted from residual substrate-bound proteins (RSBP), and cellulosomes secreted by Clostridium thermocellum B8 during growth in the presence of microcrystalline cellulose as a carbon source. The second goal was to evaluate their potential use as enzymatic blends for hydrolyzing agro-industrial residues to produce fermentable sugars. Protein identification through LC-MS/MS mass spectrometry showed that the RSBP sample, in addition to cellulosomal proteins, contains a wide variety of proteins, including those without a well-characterized role in plant cell wall degradation. The RSBP subsample defined as purified cellulosomes (PC) consists mainly of glycoside hydrolases grouped in families 5, 8, 9, 10 and 48. Dynamic light scattering, DLS, analysis of PC resulted in two protein peaks (pi1 and pi2) presenting molecular masses in agreement with those previously described for cellulosomes and polycellulosomes. These peaks weren't detected after PC treatment with 1.0% Tween. PC and RSBP presented maximal activities at temperatures ranging from 60° to 70°C and at pH 5.0. RSBP retained almost all of its activity after incubation at 50, 60 and 70°C and PC showed remarkable thermostability at 50 and 60°C. RSBP holocellullolytic activities were inhibited by phenolic compounds, while PC showed either increasing activity or a lesser degree of inhibition. RSBP and PC hydrolyze sugar cane straw, cotton waste and microcrystalline cellulose, liberating a diversity of saccharides; however, the highest concentration of released sugar was obtained for assays carried out using PC as an enzymatic blend and after ten days at 50°C. Copyright © 2016 Elsevier Inc. All rights reserved.

Application of Short Screening Tools for Post-Traumatic Stress Disorder in the Korean Elderly Population

PubMed Central

Jang, Yu Jin; Chung, Hae Gyung; Choi, Jin Hee; Kim, Tae Yong; So, Hyung Seok

2016-01-01

Objective Post-traumatic stress disorder (PTSD) is often missed or incorrectly diagnosed in primary care settings. Although brief screening instruments may be useful in detecting PTSD, an adequate validation study has not been conducted with older adults. This study aimed to evaluate the reliability and validity of the Korean version of the primary care PTSD screen (PC-PTSD) and single-item PTSD screener (SIPS) in elderly veterans. Methods The PC-PTSD and SIPS assessments were translated into Korean, with a back-translation to the original language to verify accuracy. Vietnamese war veterans [separated into a PTSD group (n=41) and a non-PTSD group (n=99)] participated in several psychometric assessments, including the Korean versions of the PC-PTSD (PC-PTSD-K), SIPS (SIPS-K), a structured clinical interview from the Diagnostic and Statistical Manual of Mental Disorders-IV(SCID), and PTSD checklist(PCL). Results The PC-PTSD-K showed high internal consistency (Cronbach α=0.76), and the test-retest reliability of the PC-PTSD-K and SIPS-K were also high (r=0.97 and r=0.91, respectively). A total score of 3 from the PC-PTSD-K yielded the highest diagnostic efficiency, with sensitivity and specificity values of 0.90 and 0.86, respectively. The 'bothered a lot' response level from the SIPS-K showed the highest diagnostic efficiency, with sensitivity and specificity values of 0.85 and 0.89, respectively. Conclusion Our findings suggest that both PC-PTSD-K and SIPS-K have good psychometric properties with high validity and reliability for detecting PTSD symptoms in elderly Korean veterans. However, further research will be necessary to increase our understanding of PTSD characteristics in diverse groups with different types of trauma. PMID:27482241

Primary care-mental health integration and treatment retention among Iraq and Afghanistan war veterans.

PubMed

Tsan, Jack Y; Zeber, John E; Stock, Eileen M; Sun, Fangfang; Copeland, Laurel A

2012-11-01

Despite the high prevalence of posttraumatic stress disorder (PTSD) and medical comorbidity among veterans from Iraq/Afghanistan (OEF/OIF), keeping these patients engaged in health care is challenging. Primary Care-Mental Health Integration (PC-MHI), an initiative in the Veterans Health Administration (VA), sought to improve access to mental health care from within primary care. This study examined the lag between first PC-MHI visit and next mental/medical care visit, if any, and the relationship of PC-MHI with short-term (subsequent year) and long-term (4 years later) use of VA. We identified 2,470 OEF/OIF veterans receiving care during fiscal year 2006 (FY06) in a regional VA health care system. Unconditional survival analysis modeled time to next mental/medical visit and logistic regression modeled short- and long-term care as a function of PC-MHI, demographics, and clinical covariates. Of 181 patients in the PC-MHI program, 60%/18% returned for mental/medical care within 1 month, and 82%/74% within 1 year. Sixty-one percent (1,503) were still using the VA in FY09. Short-term mental care was related to prior-year PC-MHI. Consistent correlates of short- and long-term mental/medical care included physical comorbidity and Priority 1 status. Most patients attended mental health appointments subsequent to PC-MHI, and PC-MHI was correlated with mental health treatment retention in adjusted models for our cohort. Need for treatment, notably VA Priority 1 status and physical comorbidity, were the primary correlates of care-seeking. Developing innovative approaches to engaging new veterans in care remains imperative as multiple options will be necessary to meet the needs of these complex patients.

Assessing cancer-specific anxiety in Chinese men with prostate cancer: psychometric evaluation of the Chinese version of the Memorial Anxiety Scale for Prostate Cancer (MAX-PC).

PubMed

Huang, Qingmei; Jiang, Ping; Zhang, Zijun; Luo, Jie; Dai, Yun; Zheng, Li; Wang, Wei

2017-12-01

The Memorial Anxiety Scale for Prostate Cancer (MAX-PC) was developed to identify and assess cancer-specific anxiety among men with prostate cancer (PCa); however, there is no Chinese version. The aim of our study was to translate the English version of MAX-PC into Chinese and evaluate the psychometric properties of it. The study cohort comprised 254 participants. Internal consistency including the Cronbach's alpha coefficient and item-total correlations were used to measure the reliability of the scale. Factor structure was analyzed by exploratory factor analysis and concurrent validity by comparing MAX-PC scores with anxiety subscale scores of the Hospital Anxiety and Depression Scale (HADS). Divergent validity was assessed by correlating MAX-PC with HADS depression subscale, while discriminant ability by comparing differences in MAX-PC scores between different patient groups. The Chinese version of MAX-PC demonstrated good reliability; the Cronbach's alpha coefficient for the total and three subscales (prostate cancer anxiety, PSA anxiety, and fear of recurrence) being 0.94, 0.93, 0.82, and 0.85, respectively. Exploratory factor analysis supported the three-factor structure of the scale established in the original version. Despite the somewhat underperformed divergent validity, the scale demonstrated good concurrent validity with a strong correlation with the HADS anxiety subscale (r = 0.71, p < 0.01). Moreover, discriminant ability was demonstrated by ability to differentiate between disease stages. The MAX-PC Chinese version was confirmed to be a valid, reliable instrument and is thus appropriate for identifying and quantifying cancer-specific anxiety in Chinese PCa patients.

31P NMR and AFM studies on the destabilization of cell and model membranes by the major bovine seminal plasma protein, PDC-109.

PubMed

Damai, Rajani S; Sankhala, Rajeshwer S; Anbazhagan, Veerappan; Swamy, Musti J

2010-11-01

The effect of PDC-109 binding to dimyristoylphosphatidylcholine (DMPC) and dipalmitoylphosphatidylglycerol (DPPG) multilamellar vesicles (MLVs) and supported membranes was investigated by (31)P NMR spectroscopy and atomic force microscopy. Additionally, the effect of cholesterol on the binding of PDC-109 to phosphatidylcholine (PC) membranes was studied. Binding of PDC-109 to MLVs of DMPC and DPPG induced the formation of an isotropic signal in their (31)P NMR spectra, which increased with increasing protein/lipid ratio and temperature, consistent with protein-induced disruption of the MLVs and the formation of small unilamellar vesicles or micelles but not inverse hexagonal or cubic phases. Incorporation of cholesterol in the DMPC MLVs afforded a partial stabilization of the lamellar structure, consistent with previous reports of membrane stabilization by cholesterol. AFM results are consistent with the above findings and show that addition of PDC-109 leads to a complete breakdown of PC membranes. The fraction of isotropic signal in (31)P NMR spectra of DPPG in the presence of PDC-109 was less than that of DMPC under similar conditions, suggesting a significantly higher affinity of the protein for PC. Confocal microscopic studies showed that addition of PDC-109 to human erythrocytes results in a disruption of the plasma membrane and release of hemoglobin into the solution, which was dependent on the protein concentration and incubation time.

Syntheses, crystal structures and characterization of nitrogen-rich salts based on bis (1H-tetrazol-5-yl) methanone oxime

NASA Astrophysics Data System (ADS)

Lin, Xinyu; Guo, Weiming; Zhang, Tianhe; Huang, Jingru; Tong, Yi; Zhang, Tonglai

2017-08-01

Two nitrogen-rich energetic salts (NH4)2(bto) (1) and (NH3OH)2(bto)·H2O (2) [H2bto = Bis (1H-tetrazol-5-yl) methanone oxime] were synthesized by an improved method in which water was used as solvent. These compounds were characterized by FT-IR spectroscopy, elemental analysis and single crystal X-ray diffraction. Their crystal structures were confirmed to belong to monoclinic system with space group P21 for 1 and Pc for 2, respectively. The detailed thermal behaviours were investigated by using differential scanning calorimetry (DSC) and thermogravimetric method (TG) (decomposition temperature >250 °C). The enthalpies of formation were calculated through the experimental values of combustion enthalpy. In addition, the sensitivities toward impact and friction were tested with standard methods, and those results indicated that two compounds are all insensitive (impact >40 J and friction >360 N). In short, both of the compounds show potential usages as energetic materials. The improved process opens a door for exploring nitrogen-rich salts based on Bis (1H-tetrazol-5-yl) methanone oxime.

Fabrication of Crack-Free Photonic Crystal Films on Superhydrophobic Nanopin Surface.

PubMed

Xia, Tian; Luo, Wenhao; Hu, Fan; Qiu, Wu; Zhang, Zhisen; Lin, Youhui; Liu, Xiang Yang

2017-07-05

On the basis of their superior optical performance, photonic crystals (PCs) have been investigated as excellent candidates for widespread applications including sensors, displays, separation processes, and catalysis. However, fabrication of structurally controllable large-area PC assemblies with no defects is still a tough task. Herein, we develop an effective strategy for preparing centimeter-scale crack-free photonic crystal films by the combined effects of soft assembly and superhydrophobic nanopin surfaces. Owing to its large contact angle and low-adhesive force on the superhydrophobic substrate, the colloidal suspension exhibits a continuous retraction of the three-phase (gas-liquid-solid) contact line (TCL) in the process of solvent (water molecules) evaporation. The constantly receding TCL can bring the colloidal spheres closer to each other, which could timely close the gaps due to the loss of water molecules. As a result, close-packed and well-ordered assembly structures can be easily obtained. We expect that this work may pave the way to utilize novel superhydrophobic materials for designing and developing high-quality PCs and to apply PCs in different fields.

The electronics system for the LBNL positron emission mammography (PEM) camera

NASA Astrophysics Data System (ADS)

Moses, W. W.; Young, J. W.; Baker, K.; Jones, W.; Lenox, M.; Ho, M. H.; Weng, M.

2001-06-01

Describes the electronics for a high-performance positron emission mammography (PEM) camera. It is based on the electronics for a human brain positron emission tomography (PET) camera (the Siemens/CTI HRRT), modified to use a detector module that incorporates a photodiode (PD) array. An application-specified integrated circuit (ASIC) services the photodetector (PD) array, amplifying its signal and identifying the crystal of interaction. Another ASIC services the photomultiplier tube (PMT), measuring its output and providing a timing signal. Field-programmable gate arrays (FPGAs) and lookup RAMs are used to apply crystal-by-crystal correction factors and measure the energy deposit and the interaction depth (based on the PD/PMT ratio). Additional FPGAs provide event multiplexing, derandomization, coincidence detection, and real-time rebinning. Embedded PC/104 microprocessors provide communication, real-time control, and configure the system. Extensive use of FPGAs make the overall design extremely flexible, allowing many different functions (or design modifications) to be realized without hardware changes. Incorporation of extensive onboard diagnostics, implemented in the FPGAs, is required by the very high level of integration and density achieved by this system.

Improvement of crystal identification performance for a four-layer DOI detector composed of crystals segmented by laser processing

NASA Astrophysics Data System (ADS)

Mohammadi, Akram; Inadama, Naoko; Yoshida, Eiji; Nishikido, Fumihiko; Shimizu, Keiji; Yamaya, Taiga

2017-09-01

We have developed a four-layer depth of interaction (DOI) detector with single-side photon readout, in which segmented crystals with the patterned reflector insertion are separately identified by the Anger-type calculation. Optical conditions between segmented crystals, where there is no reflector, affect crystal identification ability. Our objective of this work was to improve crystal identification performance of the four-layer DOI detector that uses crystals segmented with a recently developed laser processing technique to include laser processed boundaries (LPBs). The detector consisted of 2 × 2 × 4mm3 LYSO crystals and a 4 × 4 array multianode photomultiplier tube (PMT) with 4.5 mm anode pitch. The 2D position map of the detector was calculated by the Anger calculation method. At first, influence of optical condition on crystal identification was evaluated for a one-layer detector consisting of a 2 × 2 crystal array with three different optical conditions between the crystals: crystals stuck together using room temperature vulcanized (RTV) rubber, crystals with air coupling and segmented crystals with LPBs. The crystal array with LPBs gave the shortest distance between crystal responses in the 2D position map compared with the crystal array coupled with RTV rubber or air due to the great amount of cross-talk between segmented crystals with LPBs. These results were used to find optical conditions offering the optimum distance between crystal responses in the 2D position map for the four-layer DOI detector. Crystal identification performance for the four-layer DOI detector consisting of an 8 × 8 array of crystals segmented with LPBs was examined and it was not acceptable for the crystals in the first layer. The crystal identification was improved for the first layer by changing the optical conditions between all 2 × 2 crystal arrays of the first layer to RTV coupling. More improvement was observed by combining different optical conditions between all crystals of the first layer and some crystals of the second and the third layers of the segmented array.

Enzymatic properties and substrate specificity of a bacterial phosphatidylcholine synthase.

PubMed

Aktas, Meriyem; Köster, Stefan; Kizilirmak, Sarah; Casanova, Javier C; Betz, Heidi; Fritz, Christiane; Moser, Roman; Yildiz, Özkan; Narberhaus, Franz

2014-08-01

Phosphatidylcholine (PC) is a rare membrane lipid in bacteria, but is crucial for virulence of the plant pathogen Agrobacterium tumefaciens and various other pathogens. Agrobacterium tumefaciens uses two independent PC biosynthesis pathways. One is dependent on the integral membrane protein PC synthase (Pcs), which catalyzes the conversion of cytidine diphosphate-diacylglycerol (CDP-DAG) and choline to PC, thereby releasing a cytidine monophosphate (CMP). Here, we show that Pcs consists of eight transmembrane segments with its N- and C-termini located in the cytoplasm. A cytoplasmic loop between the second and third membrane helix contains the majority of the conserved amino acids of a CDP-alcohol phosphotransferase motif (DGX2 ARX12 GX3 DX3 D). Using point mutagenesis, we provide evidence for a crucial role of this motif in choline binding and enzyme activity. To study the catalytic features of the enzyme, we established a purification protocol for recombinant Pcs. The enzyme forms stable oligomers and exhibits broad substrate specificity towards choline derivatives. The presence of CDP-DAG and manganese is a prerequisite for cooperative binding of choline. PC formation by Pcs is reversible and proceeds via two successive reactions. In a first choline- and manganese-independent reaction, CDP-DAG is hydrolyzed releasing a CMP molecule. The resulting phosphatidyl intermediate reacts with choline in a second manganese-dependent step to form PC. Pcs and Pcs bind by molecular sieving (1, 2, 3). © 2014 FEBS.

Solid state direct bonding of polymers by vacuum ultraviolet light below 160 nm

NASA Astrophysics Data System (ADS)

Hashimoto, Yuki; Yamamoto, Takatoki

2017-10-01

This work investigated the application of vacuum ultraviolet (VUV) irradiation to the bonding of various substrates, including glass, polycarbonate (PC), cyclic olefin polymer (COP), polydimethylsiloxane (PDMS) and polymethyl methacrylate (PMMA). This method has the advantage of being able to bond various substrates without the application of heat or adhesives, and therefore may be very useful in the fabrication of micro/nanoscale structures composed of polymers. In contrast to previous applications of this technique, the present study used VUV radiation at wavelengths at and below 160 nm so as to take advantage of the higher energy in this range. Bonding was assessed based on measuring the shear stress of various test specimens subjected to VUV irradiation and then pressed together, and a number of analytical methods were also employed to examine the irradiated surfaces in order to elucidate the morphological and chemical changes following VUV treatment. These analyses included water contact angle measurements, attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), time of flight secondary ion mass spectrometry (TOF-SIMS) and atomic force microscopy (AFM). Poor bonding was identified between combinations consisting of PMMA/PC, PMMA/COP, PMMA/PMMA, PMMA/glass, and PC/COP, whereas all other combinations resulted in successful bonding with the bonding stress values such as PC/PC = 2.0 MPa, PC/glass = 10.7 MPa and COP/COP = 1.7 MPa, respectively.

Direct identification of various copper phthalocyanine pigments in automotive paints and paint smears by laser desorption ionization mass spectrometry.

PubMed

Mukai, Tadashi; Nakazumi, Hiroyuki; Kawabata, Shin-ichirou; Kusatani, Masaru; Nakai, Seita; Honda, Sadao

2008-01-01

Direct identification of copper phthalocyanine (CuPc) and chlorinated CuPcs in paints for discrimination between blue automobile paints by means of laser desorption mass spectrometry (LDMS) in the absence of a matrix is reported. The models consisted of eight commercially available CuPc pigments applied to a piece of plain white coating paper. The relationship between the peak intensity at m/z 575 of the CuPc, the number of pulsed laser shots, and laser power was compared to optimize laser abrasion. LDMS analysis of the model paints demonstrated that all characteristic components of the CuPc pigments in the paint films were in good agreement with those in the powder pigments. Further, the chlorinated CuPcs in the paint films could be distinguished. A quantity of 42 blue paint films, representing the paints used for painting Japanese domestic trucks, was examined by LDMS analysis. Results indicate that the paints can be classified into four categories based on the chlorinated CuPc components of the paints. Therefore, LDMS spectra of CuPc pigments would be useful for the identification of paints in forensic investigations. Herein, we report the successful identification of the CuPcs in a paint smear on the frame of a bicycle damaged in a hit-and-run accident, using the LDMS spectra.

Enhancer of polycomb coordinates multiple signaling pathways to promote both cyst and germline stem cell differentiation in the Drosophila adult testis

PubMed Central

Feng, Lijuan; Shi, Zhen; Chen, Xin

2017-01-01

Stem cells reside in a particular microenvironment known as a niche. The interaction between extrinsic cues originating from the niche and intrinsic factors in stem cells determines their identity and activity. Maintenance of stem cell identity and stem cell self-renewal are known to be controlled by chromatin factors. Herein, we use the Drosophila adult testis which has two adult stem cell lineages, the germline stem cell (GSC) lineage and the cyst stem cell (CySC) lineage, to study how chromatin factors regulate stem cell differentiation. We find that the chromatin factor Enhancer of Polycomb [E(Pc)] acts in the CySC lineage to negatively control transcription of genes associated with multiple signaling pathways, including JAK-STAT and EGF, to promote cellular differentiation in the CySC lineage. E(Pc) also has a non-cell-autonomous role in regulating GSC lineage differentiation. When E(Pc) is specifically inactivated in the CySC lineage, defects occur in both germ cell differentiation and maintenance of germline identity. Furthermore, compromising Tip60 histone acetyltransferase activity in the CySC lineage recapitulates loss-of-function phenotypes of E(Pc), suggesting that Tip60 and E(Pc) act together, consistent with published biochemical data. In summary, our results demonstrate that E(Pc) plays a central role in coordinating differentiation between the two adult stem cell lineages in Drosophila testes. PMID:28196077

Pressure-tuned superconductivity and normal-state behavior in Ba (Fe0.943Co0.057)2As2 near the antiferromagnetic boundary

NASA Astrophysics Data System (ADS)

Liu, W.; Wu, Y. F.; Li, X. J.; Bud'ko, S. L.; Canfield, P. C.; Panagopoulos, C.; Li, P. G.; Mu, G.; Hu, T.; Almasan, C. C.; Xiao, H.

2018-04-01

Superconductivity in iron pnictides is unconventional and pairing may be mediated by magnetic fluctuations in the Fe sublattice. Pressure is a clean method to explore superconductivity in iron based superconductors by tuning the ground state continuously without introducing disorder. Here we present a systematic high pressure transport study in Ba (Fe1-xCox) 2As2 single crystals with x =0.057 , which is near the antiferromagnetic instability. Resistivity ρ =ρ0+A Tn was studied under applied pressure up to 7.90 GPa. The parameter n approaches a minimum value of n ≈1 at a critical pressure Pc=3.65 GPa. Near Pc, the superconducting transition temperature Tc reaches a maximum value of 25.8 K. In addition, the superconducting diamagnetism at 2 K shows a sudden change around the same critical pressure. These results may be associated with a possible quantum critical point hidden inside the superconducting dome, near optimum Tc.

Competition between spin-orbit coupling, magnetism, and dimerization in the honeycomb iridates: α -Li2IrO3 under pressure

NASA Astrophysics Data System (ADS)

Hermann, V.; Altmeyer, M.; Ebad-Allah, J.; Freund, F.; Jesche, A.; Tsirlin, A. A.; Hanfland, M.; Gegenwart, P.; Mazin, I. I.; Khomskii, D. I.; Valentí, R.; Kuntscher, C. A.

2018-02-01

Single-crystal x-ray diffraction studies with synchrotron radiation on the honeycomb iridate α -Li2IrO3 reveal a pressure-induced structural phase transition with symmetry lowering from monoclinic to triclinic at a critical pressure of Pc=3.8 GPa. According to the evolution of the lattice parameters with pressure, the transition mainly affects the a b plane and thereby the Ir hexagon network, leading to the formation of Ir-Ir dimers. These observations are independently predicted and corroborated by our ab initio density functional theory calculations where we find that the appearance of Ir-Ir dimers at finite pressure is a consequence of a subtle interplay between magnetism, correlation, spin-orbit coupling, and covalent bonding. Our results further suggest that at Pc the system undergoes a magnetic collapse. Finally we provide a general picture of competing interactions for the honeycomb lattices A2M O3 with A =Li , Na and M =Ir , Ru.

Piezo-generated charge mapping revealed through direct piezoelectric force microscopy.

PubMed

Gomez, A; Gich, M; Carretero-Genevrier, A; Puig, T; Obradors, X

2017-10-24

While piezoelectric and ferroelectric materials play a key role in many everyday applications, there are still a number of open questions related to their physics. To enhance our understanding of piezoelectrics and ferroelectrics, nanoscale characterization is essential. Here, we develop an atomic force microscopy based mode that obtains a direct quantitative analysis of the piezoelectric coefficient d 33 . We report nanoscale images of piezogenerated charge in a thick single crystal of periodically poled lithium niobate (PPLN), a bismuth ferrite (BiFO 3 ) thin film, and lead zirconate titanate (PZT) by applying a force and recording the current produced by these materials. The quantification of d 33 coefficients for PPLN (14 ± 3 pC per N) and BFO (43 ± 6 pC per N) is in agreement with the values reported in the literature. Even stronger evidence of the reliability of the method is provided by an equally accurate measurement of the significantly larger d 33 of PZT.

Inferring consistent functional interaction patterns from natural stimulus FMRI data

PubMed Central

Sun, Jiehuan; Hu, Xintao; Huang, Xiu; Liu, Yang; Li, Kaiming; Li, Xiang; Han, Junwei; Guo, Lei

2014-01-01

There has been increasing interest in how the human brain responds to natural stimulus such as video watching in the neuroimaging field. Along this direction, this paper presents our effort in inferring consistent and reproducible functional interaction patterns under natural stimulus of video watching among known functional brain regions identified by task-based fMRI. Then, we applied and compared four statistical approaches, including Bayesian network modeling with searching algorithms: greedy equivalence search (GES), Peter and Clark (PC) analysis, independent multiple greedy equivalence search (IMaGES), and the commonly used Granger causality analysis (GCA), to infer consistent and reproducible functional interaction patterns among these brain regions. It is interesting that a number of reliable and consistent functional interaction patterns were identified by the GES, PC and IMaGES algorithms in different participating subjects when they watched multiple video shots of the same semantic category. These interaction patterns are meaningful given current neuroscience knowledge and are reasonably reproducible across different brains and video shots. In particular, these consistent functional interaction patterns are supported by structural connections derived from diffusion tensor imaging (DTI) data, suggesting the structural underpinnings of consistent functional interactions. Our work demonstrates that specific consistent patterns of functional interactions among relevant brain regions might reflect the brain's fundamental mechanisms of online processing and comprehension of video messages. PMID:22440644

a Linux PC Cluster for Lattice QCD with Exact Chiral Symmetry

NASA Astrophysics Data System (ADS)

Chiu, Ting-Wai; Hsieh, Tung-Han; Huang, Chao-Hsi; Huang, Tsung-Ren

A computational system for lattice QCD with overlap Dirac quarks is described. The platform is a home-made Linux PC cluster, built with off-the-shelf components. At present the system constitutes of 64 nodes, with each node consisting of one Pentium 4 processor (1.6/2.0/2.5 GHz), one Gbyte of PC800/1066 RDRAM, one 40/80/120 Gbyte hard disk, and a network card. The computationally intensive parts of our program are written in SSE2 codes. The speed of our system is estimated to be 70 Gflops, and its price/performance ratio is better than $1.0/Mflops for 64-bit (double precision) computations in quenched QCD. We discuss how to optimize its hardware and software for computing propagators of overlap Dirac quarks.

Three-dimensional Structure of the Milky Way Dust: Modeling of LAMOST Data

NASA Astrophysics Data System (ADS)

Li, Linlin; Shen, Shiyin; Hou, Jinliang; Yuan, Haibo; Xiang, Maosheng; Chen, Bingqiu; Huang, Yang; Liu, Xiaowei

2018-05-01

We present a three-dimensional modeling of the Milky Way dust distribution by fitting the value-added star catalog of the LAMOST spectral survey. The global dust distribution can be described by an exponential disk with a scale length of 3192 pc and a scale height of 103 pc. In this modeling, the Sun is located above the dust disk with a vertical distance of 23 pc. Besides the global smooth structure, two substructures around the solar position are also identified. The one located at 150° < l < 200° and ‑5° < b < ‑30° is consistent with the Gould Belt model of Gontcharov, and the other one located at 140° < l < 165° and 0° < b < 15° is associated with the Camelopardalis molecular clouds.

Altered molecular specificity of surfactant phosphatidycholine synthesis in patients with acute respiratory distress syndrome.

PubMed

Dushianthan, Ahilanandan; Goss, Victoria; Cusack, Rebecca; Grocott, Michael P W; Postle, Anthony D

2014-11-07

Acute respiratory distress syndrome (ARDS) is a life-threatening critical illness, characterised by qualitative and quantitative surfactant compositional changes associated with premature airway collapse, gas-exchange abnormalities and acute hypoxic respiratory failure. The underlying mechanisms for this dysregulation in surfactant metabolisms are not fully explored. Lack of therapeutic benefits from clinical trials, highlight the importance of detailed in-vivo analysis and characterisation of ARDS patients according to patterns of surfactant synthesis and metabolism. Ten patients with moderate to severe ARDS were recruited. Most (90%) suffered from pneumonia. They had an infusion of methyl-D9-choline chloride and small volume bronchoalveolar lavage fluid (BALF) was obtained at 0,6,12,24,48,72 and 96 hours. Controls were healthy volunteers, who had BALF at 24 and 48 hours after methyl-D9-choline infusion. Compositional analysis and enrichment patterns of stable isotope labelling of surfactant phosphatidylcholine (PC) was determined by electrospray ionisation mass spectrometry. BALF of patients with ARDS consisted of diminished total PC and fractional PC16:0/16:0 concentrations compared to healthy controls. Compositional analysis revealed, reductions in fractional compositions of saturated PC species with elevated levels of longer acyl chain unsaturated PC species. Molecular specificity of newly synthesised PC fraction showed time course variation, with lower PC16:0/16:0 composition at earlier time points, but achieved near equilibrium with endogenous composition at 48 hours after methyl-D9-choline infusion. The enrichment of methyl-D9-choline into surfactant total PC is nearly doubled in patients, with considerable variation between individuals. This study demonstrate significant alterations in composition and kinetics of surfactant PC extracted from ARDS patients. This novel approach may facilitate biochemical phenotyping of ARDS patients according to surfactant synthesis and metabolism, enabling individualised treatment approaches for the management of ARDS patients in the future.

Role of adipocytokines and its correlation with endocrine pancreatic function in patients with pancreatic cancer.

PubMed

Gąsiorowska, Anita; Talar-Wojnarowska, Renata; Kaczka, Aleksandra; Borkowska, Anna; Czupryniak, Leszek; Małecka-Panas, Ewa

2013-01-01

Some authors suggest that adipocytokines contribute to the induction of pancreatic carcinogenesis as well as the development of endocrine insufficiency. We evaluate the circulating concentrations of leptin, resistin and visfatin in patients with newly diagnosed pancreatic cancer (PC) and relationship between serum adipocytokines level and clinicopathological features of PC. Moreover the usefulness of those adipocytokines as possible biomarkers of endocrine pancreatic function in PC has been assessed. The pilot study group consisted of 45 individuals (mean age 65.6 ± 11.5 years, BMI 21.8 ± 3.4 kg/m(2)) with newly diagnosed PC (within last 1-3 months) and 13 healthy individuals with age, gender and BMI matched to the study group. Among PC patients 18 (40%) had recently diagnosed diabetes. Fasting plasma leptin, resistin, visfatin concentrations were determined with ELISA (R&D Systems, Phoenix Pharmaceuticals) and insulin by RIA (DakoCytomation). Patients with PC as compared to controls had significantly lower plasma leptin (40.6 ± 21.3 vs 63.2 ± 16.3 pg/mL; p < 0,0008). In contrast PC patients showed more than six fold higher level of resistin (126.2 ± 143.2 vs 18.9 ± 7.2 ng/mL; p < 0.009) than controls. The median plasma visfatin was 2.8 ± 1.8 ng/mL, which was not significantly different from the controls (3.8 ± 1.1 ng/mL). When PC patients with and without diabetes were considered separately, plasma leptin concentrations among nondiabetic patients were slightly, but not significantly higher (44.6 ± 21.0) as compared to diabetics (34.5 ± 20.7). Moreover there was no difference between visfatin and resistin level in PC, among patients with and without diabetes. No significant differences between serum level of leptin, visfatin and resistin and age, gender, BMI, smoking status, tumor localization, distant metastases and pain has been found. The results of this study confirm previous findings that patients with newly diagnosed pancreatic cancer are characterized with lower level of leptin. This pilot study showed significantly higher resistin concentrations in patients with PC in comparison to healthy controls, which may be helpful in PC early diagnosis. Changes in leptin and resistin level in PC are not likely related to endocrine disorders. Copyright © 2013 IAP and EPC. Published by Elsevier B.V. All rights reserved.

Increased phosphatidylcholine (16:0/16:0) in the folliculus lymphaticus of Warthin tumor.

PubMed

He, Qian; Takizawa, Yoshinori; Hayasaka, Takahiro; Masaki, Noritaka; Kusama, Yukiko; Su, Jiping; Mineta, Hiroyuki; Setou, Mitsutoshi

2014-09-01

Warthin tumor (War-T), the second most common benign salivary gland tumor, consists mainly of neoplastic epithelium and lymphoid stroma. Some proteins and genes thought to be involved in War-T were evaluated by molecular biology and immunology. However, lipids as an important component of many tumor cells have not been well studied in War-T. To elucidate the molecular biology and pathogenesis of War-T, we investigated the visualized distribution of phosphatidylcholines (PCs) by imaging mass spectrometry (IMS). In our IMS analysis of a typical case, 10 signals were significantly different in intensity (p < 0.01) between the War-T and non-tumor (Non-T) regions. Five specific PCs were frequently found in the War-T regions of all of the samples: [PC (16:0/16:0) + K](+) (m/z 772.5), [PC (16:0/20:4) + K](+) (m/z 820.5), [PC (16:0/20:3) + K](+) (m/z 822.5), [PC (18:2/20:4) + K](+) (m/z 844.5), and [PC (18:0/20:5) + K](+) (m/z 846.5). PC (16:0/16:0) was increased specifically in the folliculus lymphaticus of War-T lymphoid stroma, suggesting a different metabolism. Localization of PC (16:0/16:0) might reflect inflammation activity participating in the pathogenesis of War-T. Thus, our IMS analysis revealed the profile of PCs specific to the War-T region. The molecules identified in our study provide important information for further studies of War-T pathogenesis.

Inter-regional changes in the performance and interpretation of spirometry in Spain: 3E study.

PubMed

López-Campos, José Luis; Soriano, Joan B; Calle, Myriam

2014-11-01

This report shows the results of a nation-wide survey on spirometry to assess regional differences. Observational cross-sectional study conducted by means of a telephone survey in 805 primary care (PC) and specialized centers (SC) in all regions. The survey contacted technicians in charge of spirometry and consisted of 36 questions related to the test. The results showed major differences between regions. Most centers had 1-2 spirometers. The number of spirometry tests per week ranged from 2 to 8.9 in PC and between 34.3 and 98.3 in SC. Some training had been given in most centers (63.6-100% in PC and 60.0-100% in SC) but not on a regular basis. Most centers used several short-acting bronchodilators for the bronchodilation test, but with insufficient inhalations (2.0-3.8 in PC and 2.0-3.3 in SC) and frequently incorrect waiting time (29.4-83.3% PC and 33.3-87.5% in SC). Daily calibration was not performed in all centers (0-100% in PC and 66.7-100% in SC). Significant inter-regional differences in spirometry quality criteria were observed, with 6 or more criteria met in 9.1-84.6% of PC centers and 37.5-100% in SC. Our results show the current situation of spirometry in primary and specialized care in Spain, highlighting considerable variability and areas for improvement. This information should be considered by health officials to improve the quality and accessibility of such tests. Copyright © 2014 SEPAR. Published by Elsevier Espana. All rights reserved.

Public awareness of palliative care in Sweden.

PubMed

Westerlund, Caroline; Tishelman, Carol; Benkel, Inger; Fürst, Carl Johan; Molander, Ulla; Rasmussen, Birgit H; Sauter, Sylvia; Lindqvist, Olav

2018-06-01

The aim of this study was to investigate the awareness of palliative care (PC) in a general Swedish population. We developed an e-survey based on a similar study conducted in Northern Ireland, consisting of 10 questions. Closed questions were primarily analyzed using descriptive statistics. Open questions were subject to inductive qualitative analysis. The study utilized a population sample of 7684 persons aged 18-66, of which 2020 responded, stratified by gender, age and region. Most participants reported 'no' ( n = 827, 41%) or 'some' ( n = 863, 43%) awareness of PC. Being female or older were associated with higher levels of awareness, as was a university-level education, working in a healthcare setting and having a friend or family member receiving PC. Most common sources of knowledge were the media, close friends and relatives receiving PC, as well as working in a healthcare setting. Aims of PC were most frequently identified as 'care before death', 'pain relief', 'dignity' and a 'peaceful death'. The preferred place of care and death was one's own home. The main barriers to raising awareness about PC were fear, shame and taboo, along with perceived lack of information and/or personal relevance. The term 'palliative care' was said to be unfamiliar by many. A number of strategies to enhance awareness and access to PC were suggested, largely reflecting the previously identified barriers. This survey found limited awareness of palliative care in an adult sample of the Swedish general public ≤ 66 years, and points to a more widespread disempowerment surrounding end-of-life issues.

(M)- and (P)-bicelaphanol A, dimeric trinorditerpenes with promising neuroprotective activity from Celastrus orbiculatus.

PubMed

Wang, Luo-Yi; Wu, Jian; Yang, Zhuo; Wang, Xu-Jie; Fu, Yan; Liu, Shuang-Zhu; Wang, Hong-Min; Zhu, Wei-Liang; Zhang, Hai-Yan; Zhao, Wei-Min

2013-04-26

(M)-Bicelaphanol A (1) and (P)-bicelaphanol A (2), two unprecedented dimeric trinorditerpenes existing as atropisomers, together with their monomer celaphanol A (3), were isolated from the root bark of Celastrus orbiculatus. The structures and absolute configurations of 1 and 2 were determined by spectroscopic and single-crystal X-ray diffraction analyses. Compound 1 exhibited a significant in vitro neuroprotective effect against a hydrogen peroxide-induced cell viability decrease in PC12 cells at 1 μM, while compounds 2 and 3 showed such effects at 10 μM.

Spin and orbital magnetic moment anisotropies of monodispersed bis(phthalocyaninato)terbium on a copper surface.

PubMed

Stepanow, Sebastian; Honolka, Jan; Gambardella, Pietro; Vitali, Lucia; Abdurakhmanova, Nasiba; Tseng, Tzu-Chun; Rauschenbach, Stephan; Tait, Steven L; Sessi, Violetta; Klyatskaya, Svetlana; Ruben, Mario; Kern, Klaus

2010-09-01

The magnetic properties of isolated TbPc(2) molecules supported on a Cu(100) surface are investigated by X-ray magnetic circular dichroism at 8 K in magnetic fields up to 5 T. The crystal field and magnetic properties of single molecules are found to be robust upon adsorption on a metal substrate. The Tb magnetic moment has Ising-like magnetization; XMCD spectra combined with multiplet calculations show that the saturation orbital and spin magnetic moment values reach 3 and 6 mu(B), respectively.

Role of local assembly in the hierarchical crystallization of associating colloidal hard hemispheres

NASA Astrophysics Data System (ADS)

Lei, Qun-li; Hadinoto, Kunn; Ni, Ran

2017-10-01

Hierarchical self-assembly consisting of local associations of simple building blocks for the formation of complex structures widely exists in nature, while the essential role of local assembly remains unknown. In this work, by using computer simulations, we study a simple model system consisting of associating colloidal hemispheres crystallizing into face-centered-cubic crystals comprised of spherical dimers of hemispheres, focusing on the effect of dimer formation on the hierarchical crystallization. We found that besides assisting the crystal nucleation because of increasing the symmetry of building blocks, the association between hemispheres can also induce both reentrant melting and reentrant crystallization depending on the range of interaction. Especially when the interaction is highly sticky, we observe a novel reentrant crystallization of identical crystals, which melt only in a certain temperature range. This offers another axis in fabricating responsive crystalline materials by tuning the fluctuation of local association.

Thermoluminescence dosimeter

DOEpatents

Zendle, R.

1983-11-03

A thermoluminescence dosimeter having a very small rate of decline of sensitivity during subsequent uses after heating is disclosed. The dosimeter includes a detector crystal and a glass enclosure in which the detector crystal is located. The glass enclosure is air tight and is filled with a super dry inert fill gas. The inert fill gas is nonreactive with the detector crystal when the detector crystal is heated to thermoluminescence. The fill gas is selected from the group consisting of air, nitrogen, and argon, suitable admixed with 5 to 25 percent helium. The detector crystal consists essentially of calcium fluoride. The fill gas is preferably contained at a subatmospheric pressure in the glass enclosure.

Thermoluminescence dosimeter

DOEpatents

Zendle, Robert

1985-01-01

A thermoluminescence dosimeter having a very small rate of decline of sensitivity during subsequent uses after heating is disclosed. The dosimeter includes a detector crystal and a glass enclosure in which the detector crystal is located. The glass enclosure is air tight and is filled with a super dry inert fill gas. The inert fill gas is nonreactive with the detector crystal when the detector crystal is heated to thermoluminescence. The fill gas is selected from the group consisting of air, nitrogen, and argon, suitable admixed with 5 to 25 percent helium. The detector crystal consists essentially of calcium fluoride. The fill gas is preferably contained at a subatmospheric pressure in the glass enclosure.

A Broadband THz-TDS System Based on DSTMS Emitter and LTG InGaAs/InAlAs Photoconductive Antenna Detector

PubMed Central

Zhang, Ying; Zhang, Xiaoling; Li, Shaoxian; Gu, Jianqiang; Li, Yanfeng; Tian, Zhen; Ouyang, Chunmei; He, Mingxia; Han, Jiaguang; Zhang, Weili

2016-01-01

We demonstrate a 4-f terahertz time-domain spectroscopy (THz-TDS) system using an organic crystal DSTMS as the THz emitter and a low temperature grown (LTG) InGaAs/InAlAs photoconductive antenna as the receiver. The system covers a frequency range from 0.2 up to 8 THz. The influences of the pump laser power, the probe laser power and the azimuthal angle of the DSTMS crystal on the time-domain THz amplitude are experimentally analyzed. The frequency accuracy of the system is verified by measuring two metamaterial samples and a lactose film in this THz-TDS system. The proposed combination of DSTMS emission and PC antenna detection realizes a compact and low-cost THz-TDS scheme with an ultra-broad bandwidth, which may promote the development and the applications of THz-TDS techniques. PMID:27244689

A Broadband THz-TDS System Based on DSTMS Emitter and LTG InGaAs/InAlAs Photoconductive Antenna Detector.

PubMed

Zhang, Ying; Zhang, Xiaoling; Li, Shaoxian; Gu, Jianqiang; Li, Yanfeng; Tian, Zhen; Ouyang, Chunmei; He, Mingxia; Han, Jiaguang; Zhang, Weili

2016-05-31

We demonstrate a 4-f terahertz time-domain spectroscopy (THz-TDS) system using an organic crystal DSTMS as the THz emitter and a low temperature grown (LTG) InGaAs/InAlAs photoconductive antenna as the receiver. The system covers a frequency range from 0.2 up to 8 THz. The influences of the pump laser power, the probe laser power and the azimuthal angle of the DSTMS crystal on the time-domain THz amplitude are experimentally analyzed. The frequency accuracy of the system is verified by measuring two metamaterial samples and a lactose film in this THz-TDS system. The proposed combination of DSTMS emission and PC antenna detection realizes a compact and low-cost THz-TDS scheme with an ultra-broad bandwidth, which may promote the development and the applications of THz-TDS techniques.

Band transition and topological interface modes in 1D elastic phononic crystals.

PubMed

Yin, Jianfei; Ruzzene, Massimo; Wen, Jihong; Yu, Dianlong; Cai, Li; Yue, Linfeng

2018-05-01

In this report, we design a one-dimensional elastic phononic crystal (PC) comprised of an Aluminum beam with periodically arranged cross-sections to study the inversion of bulk bands due to the change of topological phases. As the geometric parameters of the unit cell varies, the second bulk band closes and reopens forming a topological transition point. This phenomenon is confirmed for both longitudinal waves and bending waves. By constructing a structural system formed by two PCs with different topological phases, for the first time, we experimentally demonstrate the existence of interface mode within the bulk band gap as a result of topological transition for both longitudinal and bending modes in elastic systems, although for bending modes, additional conditions have to be met in order to have the interface mode due to the dispersive nature of the bending waves in uniform media compared to the longitudinal waves.

Lipophilicity-dependent ruthenium N-heterocyclic carbene complexes as potential anticancer agents.

PubMed

Lv, Gaochao; Guo, Liubin; Qiu, Ling; Yang, Hui; Wang, Tengfei; Liu, Hong; Lin, Jianguo

2015-04-28

Five Ru(II)-N-heterocyclic carbenes (NHC) (1-5) were synthesized by reacting the appropriately substituted imidazolium chlorides with Ag2O, forming the NHC-silver chloride in situ followed by transmetalation with dimeric p-cymene ruthenium(II) dichloride. All the complexes were characterized by NMR and ESI-MS, and complex 1 was also characterized by single-crystal X-ray diffraction. The IC50 values of these five complexes were determined by the MTT-based assay on four human cancer cell lines, SKOV-3 (ovarian), PC-3 (prostate), MDA-MB-231 (breast) and EC109 (esophagus). The cytotoxicities of these complexes changed from a moderate effect to a fine one, corresponding to the increasing lipophilicity order of the complex of 2 < 1 < 3 < 4 < 5 (0.91, 0.88, 1.36, 1.85 and 2.62 for 1–5 respectively). Complex 5 showed the most cytotoxicity with the IC50 values 10.3 ± 0.3 μM for SKOV-3, 2.9 ± 0.1 μM for PC-3, 8.2 ± 0.6 μM for MDA-MB-231, 6.4 ± 0.2 μM for EC109 cell lines. Due to the superior cytotoxicity of complex 5 against the PC-3 cell lines, further biological evaluations were carried out to elucidate its action mechanism. The morphologic changes and cell cycle analysis showed that complex 5 can inhibit PC-3 cell lines by inducing cell cycle arrest at the G2/M phase. The DNA binding experiments further demonstrate that complex 5 has a better binding ability for DNA (Kb = 2.2 × 10(6) M(-1)) than complexes 1-4 (3.8 × 10(5), 7.0 × 10(5), 5.7 × 10(5), and 1.9 × 10(5) respectively).

Evaluation of FPGA to PC feedback loop

NASA Astrophysics Data System (ADS)

Linczuk, Pawel; Zabolotny, Wojciech M.; Wojenski, Andrzej; Krawczyk, Rafal D.; Pozniak, Krzysztof T.; Chernyshova, Maryna; Czarski, Tomasz; Gaska, Michal; Kasprowicz, Grzegorz; Kowalska-Strzeciwilk, Ewa; Malinowski, Karol

2017-08-01

The paper presents the evaluation study of the performance of the data transmission subsystem which can be used in High Energy Physics (HEP) and other High-Performance Computing (HPC) systems. The test environment consisted of Xilinx Artix-7 FPGA and server-grade PC connected via the PCIe 4xGen2 bus. The DMA engine was based on the Xilinx DMA for PCI Express Subsystem1 controlled by the modified Xilinx XDMA kernel driver.2 The research is focused on the influence of the system configuration on achievable throughput and latency of data transfer.

Effect of local structures on crystallization in deeply undercooled metallic glass-forming liquids

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

Jiang, S. Q.; Li, M. Z., E-mail: maozhili@ruc.edu.cn; Wu, Z. W.

2016-04-21

The crystallization mechanism in deeply undercooled ZrCu metallic glass-forming liquids was investigated via molecular dynamics simulations. It was found that the crystallization process is mainly controlled by the growth of crystal nuclei formed by the BCC-like atomic clusters, consistent with experimental speculations. The crystallization rate is found to relate to the number of growing crystal nuclei in the crystallization process. The crystallization rate in systems with more crystal nuclei is significantly hindered by the larger surface fractions of crystal nuclei and their different crystalline orientations. It is further revealed that in the crystallization in deeply undercooled regions, the BCC-like crystalmore » nuclei are formed from the inside of the precursors formed by the FCC-like atomic clusters, and growing at the expense of the precursors. Meanwhile, the precursors are expanding at the expense of the outside atomic clusters. This process is consistent with the so-called Ostwald step rule. The atomic structures of metallic glasses are found to have significant impact on the subsequent crystallization process. In the Zr{sub 85}Cu{sub 15} system, the stronger spatial correlation of Cu atoms could hinder the crystallization processes in deeply undercooled regions.« less

Thin film organic photodetectors for indirect X-ray detection demonstrating low dose rate sensitivity at low voltage operation

NASA Astrophysics Data System (ADS)

Starkenburg, Daken J.; Johns, Paul M.; Baciak, James E.; Nino, Juan C.; Xue, Jiangeng

2017-12-01

Developments in the field of organic semiconductors have generated organic photodetectors with high quantum efficiency, wide spectral sensitivity, low power consumption, and unique form factors that are flexible and conformable to their substrate shape. In this work, organic photodetectors coupled with inorganic CsI(Tl) scintillators are used to showcase the low dose rate sensitivity that is enabled when high performance organic photodetectors and scintillator crystals are integrated. The detection capability of these organic-inorganic coupled systems to high energy radiation highlights their potential as an alternative to traditional photomultiplier tubes for nuclear spectroscopy applications. When exposed to Bremsstrahlung radiation produced from an X-ray generator, SubPc:C60, AlPcCl:C70, and P3HT:PC61BM thin film photodetectors with active layer thicknesses less than 100 nm show detection of incident radiation at low and no applied bias. Remarkably low dose rates, down to at least 0.18 μGy/s, were detectable with a characteristic linear relationship between exposure rate and photodetector current output. These devices also demonstrate sensitivities as high as 5.37 mC Gy-1 cm-2 when coupled to CsI(Tl). Additionally, as the tube voltage across the X-ray generator was varied, these organic-inorganic systems showed their ability to detect a range of continuous radiation spectra spanning several hundred keV.

Synthetic and structural investigations of mercurous and mercuric organophosphonates and phenylarsonates

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

Padalwar, Nitin Balkrushna; Vidyasagar, Kanamaluru

2016-11-15

The following twelve mercurous and mercuric organophosphomates, bis/diphosphonates and phenylarsonates have been isolated and structurally characterized by single crystal X-ray diffraction, {sup 13}C-and {sup 31}P NMR, infrared and Raman spectroscopic methods: Hg{sub 2}(HO{sub 3}PC{sub 6}H{sub 5}){sub 2}(1), Hg{sub 2}(HO{sub 3}P(C{sub 6}H{sub 4})PO{sub 3}H)(2), Hg{sub 2}(HO{sub 3}P(C{sub 6}H{sub 4}){sub 2}PO{sub 3}H)(3), Hg{sub 2}(HO{sub 3}P(CH{sub 2}){sub 4}PO{sub 3}H)(4), Hg{sub 2}(O{sub 3}PC{sub 6}H{sub 5})·H{sub 2}O(5), (Hg{sub 2}){sub 2}(O{sub 3}P(CH{sub 2}){sub 2}PO{sub 3})(6), (Hg{sub 2}){sub 2}(O{sub 3}P(CH{sub 2}){sub 3}PO{sub 3})(7), Hg(O{sub 3}PC{sub 6}H{sub 5})·H{sub 2}O(8), Hg(O{sub 3}PCH{sub 2}C{sub 6}H{sub 5})·H{sub 2}O(9), Hg(O{sub 3}AsC{sub 6}H{sub 5})·H{sub 2}O(10), Hg{sub 3}(O{sub 3}AsC{sub 6}H{sub 5}){sub 2}(HO{sub 3}AsC{sub 6}H{submore » 5}){sub 2}(11) and (Hg{sub 2})Hg{sub 3}(O{sub 3}P(C{sub 6}H{sub 4})PO{sub 3}){sub 2}·2H{sub 2}O(12). Compounds 1–7 are the first examples of mercurous phosphonates and di/bisphosphonates. They contain Hg{sub 2}O{sub 6} units, which consist of Hg{sub 2}{sup 2+} cations with Hg-Hg bond of ~2.5 Å length. Phenylphosphonates 1 and 5 are layered compounds, whereas bis/diphosphonates 2, 3, 4, 6 and 7 have pillared-layered and three-dimensional structures. Compounds 8–11 are layered mercuric phosphonates and phenylarsonates. Compound 12 is a three-dimensional mixed-valent mercury phenylenebisphosphonate. - Graphical abstract: The first examples of mercurous organophosphonates and organodiphosphonates have layered, pillared-layered and three-dimensional structures.« less

An important rule for realizing metal → half-metal → semiconductor transition in single-molecule junctions

NASA Astrophysics Data System (ADS)

Zeng, Jing; Chen, Ke-Qiu; Long, Mengqiu

2017-06-01

Recently, Zhong et al (2015 Nano Lett. 15 8091) found that two additional hydrogen atoms can be adsorbed to the opposite aza-bridging nitrogen atoms of the manganese phthalocyanine (MnPc) macrocycle when exposed to H2. Thus the symmetry of the MnPc molecule is changed from 4-fold to 2-fold. Motivated by this recent experiment, we theoretically investigate a MnPc-based single-molecule junction in this work and propose a simple and reliable way to realize the transition of its electronic properties. On the basis of spin-polarized density-functional theory calculations combined with the Keldysh nonequilibrium Green’s technique, we find that the gradual hydrogenation in MnPc molecules gives rise to the changes of the hardness of the electron density and spin-selective orbital decoupling, which eventually leads to the realization of the first ever metal  →  half-metal  →  semiconductor transition behavior in single-molecule junctions. Analysis of molecular projected self-consistent Hamiltonian, Mulliken population, and local density of states also reveals an important rule for realizing this transition behavior. Our research confirms that the hydrogenation of MnPc molecules can realize various molecular functionalities in unitary material background.

Polycystin-1 promotes PKC{alpha}-mediated NF-{kappa}B activation in kidney cells

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

Banzi, Manuela; Aguiari, Gianluca; Trimi, Viky

2006-11-17

Polycystin-1 (PC1), the PKD1 gene product, is a membrane receptor which regulates many cell functions, including cell proliferation and apoptosis, both typically increased in cyst lining cells in autosomal dominant polycystic kidney disease. Here we show that PC1 upregulates the NF-{kappa}B signalling pathway in kidney cells to prevent cell death. Human embryonic kidney cell lines (HEK293{sup CTT}), stably expressing a PC1 cytoplasmic terminal tail (CTT), presented increased NF-{kappa}B nuclear levels and NF-{kappa}B-mediated luciferase promoter activity. This, consistently, was reduced in HEK293 cells in which the endogenous PC1 was depleted by RNA interference. CTT-dependent NF-{kappa}B promoter activation was mediated by PKC{alpha}more » because it was blocked by its specific inhibitor Ro-320432. Furthermore, it was observed that apoptosis, which was increased in PC1-depleted cells, was reduced in HEK293{sup CTT} cells and in porcine kidney LtTA cells expressing a doxycycline-regulated CTT. Staurosporine, a PKC inhibitor, and parthenolide, a NF-{kappa}B inhibitor, significantly reduced the CTT-dependent antiapoptotic effect. These data reveal, therefore, a novel pathway by which polycystin-1 activates a PKC{alpha}-mediated NF-{kappa}B signalling and cell survival.« less

Expressed emotion and its relationship to adolescent depression and antisocial behavior in northern Taiwan.

PubMed

Lue, Bee-Horng; Wu, Wen-Chi; Yen, Lee-Lan

2010-02-01

Despite widespread recognition of the occurrence of antisocial behavior and depression in adolescents, the specifics of the relationship between them have not been clarified. The purpose of this study was to investigate the role of expressed emotion as a proximal factor for depression and antisocial behavior among adolescents, by looking at direct and indirect relationships. Secondary data analysis using path analysis was carried out on 2004 data from the Child and Adolescent Behaviors in Long-term Evaluation project. The study sample consisted of 1599 seventh-grade students in Northern Taiwan. Variables included family factors, personal factors (sex and academic performance), expressed emotion [emotional involvement (EI) and perceived criticism (PC)], depression, and antisocial behavior. We found that one dimension of expressed emotion, PC, directly influenced student depression and related indirectly to antisocial behavior. Depression was an important mediator between PC and antisocial behavior. Another dimension, EI, did not influence either depression or antisocial behavior. Sex was related directly to expressed emotion, depression, and antisocial behavior, and also indirectly to antisocial behavior through PC and depression. Academic performance was related directly to expressed emotion and indirectly to antisocial behavior through PC and depression. Greater PC from parents directly contributed to higher levels of student depression and was related indirectly to more student antisocial behavior. It is suggested that parents should decrease overly critical parenting styles to promote adolescent mental health and avoid the development of antisocial behavior. (c) 2010 Formosan Medical Association & Elsevier. Published by Elsevier B.V. All rights reserved.

Ionic network analysis of tectosilicates: the example of coesite at variable pressure.

PubMed

Reifenberg, Melina; Thomas, Noel W

2018-04-01

The method of ionic network analysis [Thomas (2017). Acta Cryst. B73, 74-86] is extended to tectosilicates through the example of coesite, the high-pressure polymorph of SiO 2 . The structural refinements of Černok et al. [Z. Kristallogr. (2014), 229, 761-773] are taken as the starting point for applying the method. Its purpose is to predict the unit-cell parameters and atomic coordinates at (p-T-X) values in-between those of diffraction experiments. The essential development step for tectosilicates is to define a pseudocubic parameterization of the O 4 cages of the SiO 4 tetrahedra. The six parameters a PC , b PC , c PC , α PC , β PC and γ PC allow a full quantification of the tetrahedral structure, i.e. distortion and enclosed volume. Structural predictions for coesite require that two separate quasi-planar networks are defined, one for the silicon ions and the other for the O 4 cage midpoints. A set of parametric curves is used to describe the evolution with pressure of these networks and the pseudocubic parameters. These are derived by fitting to the crystallographic data. Application of the method to monoclinic feldspars and to quartz and cristobalite is discussed. Further, a novel two-parameter quantification of the degree of tetrahedral distortion is described. At pressures in excess of ca 20.45 GPa it is not possible to find a self-consistent solution to the parametric curves for coesite, pointing to the likelihood of a phase transition.

Alamethicin in lipid bilayers: combined use of X-ray scattering and MD simulations.

PubMed

Pan, Jianjun; Tieleman, D Peter; Nagle, John F; Kucerka, Norbert; Tristram-Nagle, Stephanie

2009-06-01

We study fully hydrated bilayers of two di-monounsaturated phospholipids diC18:1PC (DOPC) and diC22:1PC with varying amounts of alamethicin (Alm). We combine the use of X-ray diffuse scattering and molecular dynamics simulations to determine the orientation of alamethicin in model lipids. Comparison of the experimental and simulated form factors shows that Alm helices are inserted transmembrane at high humidity and high concentrations, in agreement with earlier results. The X-ray scattering data and the MD simulations agree that membrane thickness changes very little up to 1/10 Alm/DOPC. In contrast, the X-ray data indicate that the thicker diC22:1PC membrane thins with added Alm, a total decrease in thickness of 4 A at 1/10 Alm/diC22:1PC. The different effect of Alm on the thickness changes of the two bilayers is consistent with Alm having a hydrophobic thickness close to the hydrophobic thickness of 27 A for DOPC; Alm is then mismatched with the 7 A thicker diC22:1PC bilayer. The X-ray data indicate that Alm decreases the bending modulus (K(C)) by a factor of approximately 2 in DOPC and a factor of approximately 10 in diC22:1PC membranes (P/L approximately 1/10). The van der Waals and fluctuational interactions between bilayers are also evaluated through determination of the anisotropic B compressibility modulus.

Novel HER3/MUC4 oncogenic signaling aggravates the tumorigenic phenotypes of pancreatic cancer cells.

PubMed

Lakshmanan, Imayavaramban; Seshacharyulu, Parthasarathy; Haridas, Dhanya; Rachagani, Satyanarayana; Gupta, Suprit; Joshi, Suhasini; Guda, Chittibabu; Yan, Ying; Jain, Maneesh; Ganti, Apar K; Ponnusamy, Moorthy P; Batra, Surinder K

2015-08-28

Several studies have demonstrated that MUC4 is involved in progression and metastasis of pancreatic cancer (PC). Here, we report that HER3/MUC4 interaction in HER2 low cells is critical in driving pancreatic tumorigenesis. Upon HER2 knockdown, we observed elevated expression of HER3 and MUC4 and their interactions, which was confirmed by immunoprecipitation and bioinformatics analyses. In paired human PC tissues, higher percentage of HER3 positivity (10/33, 30.3%; p = 0.001) was observed than HER2 (5/33, 15.1%; p = 0.031), which was further confirmed in spontaneous mice (KPC; KrasG12D; Trp53R172H/+; Pdx-Cre) tumors of different weeks. Mechanistically, increased phosphorylation of ERK and expression of PI3K and c-Myc were observed in HER2 knockdown cells, suggesting a positive role for HER3/MUC4 in HER2 low cells. Further, HER2 knockdown resulted in increased proliferation, motility and tumorigenicity of PC cells. Consistently, transient knockdown of HER3 by siRNA in HER2 knockdown cells led to decreased proliferation. These observations led us to conclude that HER3 interacts with MUC4 to promote proliferation in HER2 low PC cells. Further, deficiency of both HER2 and HER3 leads to decreased proliferation of PC cells. Hence targeting these newly identified HER3/MUC4 signals would improve the PC patients survival by intercepting MUC4 mediated oncogenic signaling.

Novel HER3/MUC4 oncogenic signaling aggravates the tumorigenic phenotypes of pancreatic cancer cells

PubMed Central

Lakshmanan, Imayavaramban; Seshacharyulu, Parthasarathy; Haridas, Dhanya; Rachagani, Satyanarayana; Gupta, Suprit; Joshi, Suhasini; Guda, Chittibabu; Yan, Ying; Jain, Maneesh; Ganti, Apar K.; Ponnusamy, Moorthy P.; Batra, Surinder K.

2015-01-01

Several studies have demonstrated that MUC4 is involved in progression and metastasis of pancreatic cancer (PC). Here, we report that HER3/MUC4 interaction in HER2 low cells is critical in driving pancreatic tumorigenesis. Upon HER2 knockdown, we observed elevated expression of HER3 and MUC4 and their interactions, which was confirmed by immunoprecipitation and bioinformatics analyses. In paired human PC tissues, higher percentage of HER3 positivity (10/33, 30.3%; p = 0.001) was observed than HER2 (5/33, 15.1%; p = 0.031), which was further confirmed in spontaneous mice (KPC; KrasG12D; Trp53R172H/+; Pdx-Cre) tumors of different weeks. Mechanistically, increased phosphorylation of ERK and expression of PI3K and c-Myc were observed in HER2 knockdown cells, suggesting a positive role for HER3/MUC4 in HER2 low cells. Further, HER2 knockdown resulted in increased proliferation, motility and tumorigenicity of PC cells. Consistently, transient knockdown of HER3 by siRNA in HER2 knockdown cells led to decreased proliferation. These observations led us to conclude that HER3 interacts with MUC4 to promote proliferation in HER2 low PC cells. Further, deficiency of both HER2 and HER3 leads to decreased proliferation of PC cells. Hence targeting these newly identified HER3/MUC4 signals would improve the PC patients survival by intercepting MUC4 mediated oncogenic signaling. PMID:26035354

Development of dielectrophoresis MEMS device for PC12 cell patterning to elucidate nerve-network generation

NASA Astrophysics Data System (ADS)

Nakamachi, Eiji; Koga, Hirotaka; Morita, Yusuke; Yamamoto, Koji; Sakamoto, Hidetoshi

2018-01-01

We developed a PC12 cell trapping and patterning device by combining the dielectrophoresis (DEP) methodology and the micro electro mechanical systems (MEMS) technology for time-lapse observation of morphological change of nerve network to elucidate the generation mechanism of neural network. We succeeded a neural network generation, which consisted of cell body, axon and dendrites by using tetragonal and hexagonal cell patterning. Further, the time laps observations was carried out to evaluate the axonal extension rate. The axon extended in the channel and reached to the target cell body. We found that the shorter the PC12 cell distance, the less the axonal connection time in both tetragonal and hexagonal structures. After 48 hours culture, a maximum success rate of network formation was 85% in the case of 40 μm distance tetragonal structure.

A New PC and LabVIEW Package Based System for Electrochemical Investigations.

PubMed

Stević, Zoran; Andjelković, Zoran; Antić, Dejan

2008-03-15

The paper describes a new PC and LabVIEW software package based system forelectrochemical research. An overview of well known electrochemical methods, such aspotential measurements, galvanostatic and potentiostatic method, cyclic voltammetry andEIS is given. Electrochemical impedance spectroscopy has been adapted for systemscontaining large capacitances. For signal generation and recording of the response ofinvestigated electrochemical cell, a measurement and control system was developed, basedon a PC P4. The rest of the hardware consists of a commercially available AD-DA converterand an external interface for analog signal processing. The interface is a result of authorsown research. The software platform for desired measurement methods is LabVIEW 8.2package, which is regarded as a high standard in the area of modern virtual instruments. Thedeveloped system was adjusted, tested and compared with commercially available systemand ORCAD simulation.

[Psychometric properties of scales of professional competence and treatment by health personnel in outpatient hospital surgeries].

PubMed

Bermejo Alegría, Rosa M; Hidalgo Montesinos, M Dolores; Parra Hidalgo, Pedro; Más Castillo, Adelia; Gomis Cebrián, Rafael

2011-04-01

The aim of this study was to analyze the psychometric properties of two scales that assess the perceived quality and patient satisfaction with outpatient surgery in the Health Service of Murcia. These scales assess the degree of Professional Competence (PC) and Personnel Treatment (PT). The scales were administered to a sample of 2017 users of outpatient surgery in the Health Service of Murcia during the years 2008 and 2009. Exploratory factor analysis indicates a unidimensional structure for each scale. Internal consistency was adequate: .68 for PC and .75 for PT. The correlation between the PC scale and patients' global satisfaction was positive and statistically significant. The correlation between the PT scale and patients' global satisfaction was also statistically significant. The scales have shown their utility to detect areas of improvement and to plan intervention strategies.

Kicking against the PRCs – A Domesticated Transposase Antagonises Silencing Mediated by Polycomb Group Proteins and Is an Accessory Component of Polycomb Repressive Complex 2

PubMed Central

Perera, Pumi; Mora-García, Santiago; de Leau, Erica; Thornton, Harry; de Alves, Flavia Lima; Rapsilber, Juri; Yang, Suxin; James, Geo Velikkakam; Schneeberger, Korbinian; Finnegan, E. Jean; Turck, Franziska; Goodrich, Justin

2015-01-01

The Polycomb group (PcG) and trithorax group (trxG) genes play crucial roles in development by regulating expression of homeotic and other genes controlling cell fate. Both groups catalyse modifications of chromatin, particularly histone methylation, leading to epigenetic changes that affect gene activity. The trxG antagonizes the function of PcG genes by activating PcG target genes, and consequently trxG mutants suppress PcG mutant phenotypes. We previously identified the ANTAGONIST OF LIKE HETEROCHROMATIN PROTEIN1 (ALP1) gene as a genetic suppressor of mutants in the Arabidopsis PcG gene LIKE HETEROCHROMATIN PROTEIN1 (LHP1). Here, we show that ALP1 interacts genetically with several other PcG and trxG components and that it antagonizes PcG silencing. Transcriptional profiling reveals that when PcG activity is compromised numerous target genes are hyper-activated in seedlings and that in most cases this requires ALP1. Furthermore, when PcG activity is present ALP1 is needed for full activation of several floral homeotic genes that are repressed by the PcG. Strikingly, ALP1 does not encode a known chromatin protein but rather a protein related to PIF/Harbinger class transposases. Phylogenetic analysis indicates that ALP1 is broadly conserved in land plants and likely lost transposase activity and acquired a novel function during angiosperm evolution. Consistent with this, immunoprecipitation and mass spectrometry (IP-MS) show that ALP1 associates, in vivo, with core components of POLYCOMB REPRESSIVE COMPLEX 2 (PRC2), a widely conserved PcG protein complex which functions as a H3K27me3 histone methyltransferase. Furthermore, in reciprocal pulldowns using the histone methyltransferase CURLY LEAF (CLF), we identify not only ALP1 and the core PRC2 components but also plant-specific accessory components including EMBRYONIC FLOWER 1 (EMF1), a transcriptional repressor previously associated with PRC1-like complexes. Taken together our data suggest that ALP1 inhibits PcG silencing by blocking the interaction of the core PRC2 with accessory components that promote its HMTase activity or its role in inhibiting transcription. ALP1 is the first example of a domesticated transposase acquiring a novel function as a PcG component. The antagonistic interaction of a modified transposase with the PcG machinery is novel and may have arisen as a means for the cognate transposon to evade host surveillance or for the host to exploit features of the transposition machinery beneficial for epigenetic regulation of gene activity. PMID:26642436

Interactions of zinc octacarboxyphthalocyanine with selected amino acids and with albumin

NASA Astrophysics Data System (ADS)

Kliber, Marta; Broda, Małgorzata A.; Nackiewicz, Joanna

2016-02-01

Effect of selected amino acids (glycine, L-histidine, L-cysteine, L-serine, L-tryptophan) and albumin on the spectroscopic properties and photostability of zinc octacarboxyphthalocyanine (ZnPcOC) was explored in the phosphate buffer at a pH of 7.0. The photodegradation of ZnPcOC alone and in the presence of amino acids or albumin has been investigated in aqueous phase using UV-366 nm and daylight irradiation. Kinetic analysis showed that the interaction with amino acids or albumin enhances the photostability of ZnPcOC. To answer the question of how zinc phthalocyanine interacts with amino acids extensive DFT calculations were performed. Analysis of the optimized geometry features of ZnPcOC: amino acids complexes in the gas phase and in water environment as well as the BSSE corrected interaction energies indicates that the more likely is the formation of equatorial complexes in which H-bonds are formed between the COOH groups of the phthalocyanine and carboxyl or amino groups of amino acids. UV-Vis spectra calculated by employing time dependent density functional theory (TD-DFT) are also consistent with this conclusion.

Magnetic resonance spectroscopy in mild cognitive impairment: systematic review and meta-analysis.

PubMed

Tumati, Shankar; Martens, Sander; Aleman, André

2013-12-01

Research using proton magnetic resonance spectroscopy (MRS) can potentially elucidate metabolite changes representing early degeneration in Mild Cognitive Impairment (MCI), an early stage of dementia. We integrated the published literature using meta-analysis to identify patterns of metabolite changes in MCI. 29 MRS studies (with a total of 607 MCI patients and 862 healthy controls) were classified according to brain regions. Hedges' g was used as effect size in a random effects model. N-Acetyl Aspartate (NAA) measures were consistently reduced in posterior cingulate (PC), hippocampus, and the paratrigonal white matter (PWM). Creatine (Cr) concentration was reduced in the hippocampus and PWM. Choline (Cho) concentration was reduced in the hippocampus while Cho/Cr ratio was raised in the PC. Myo-inositol (mI) concentration was raised in the PC and mI/Cr ratio was raised in the hippocampus. NAA/mI ratio was reduced in the PC. NAA may be the most reliable marker of brain dysfunction in MCI though mI, Cho, and Cr may also contribute towards this. Copyright © 2013 Elsevier Ltd. All rights reserved.

Cluster observations of EMIC triggered emissions in association with Pc1 waves near Earth's plasmapause

NASA Astrophysics Data System (ADS)

Pickett, J. S.; Grison, B.; Omura, Y.; Engebretson, M. J.; Dandouras, I.; Masson, A.; Adrian, M. L.; Santolík, O.; Décréau, P. M. E.; Cornilleau-Wehrlin, N.; Constantinescu, D.

2010-05-01

The Cluster spacecraft were favorably positioned on the nightside near the equatorial plasmapause of Earth at L ˜ 4.3 on 30 March 2002 to observe electromagnetic ion cyclotron (EMIC) rising tone emissions in association with Pc1 waves at 1.5 Hz. The EMIC rising tone emissions were found to be left-hand, circularly polarized, dispersive, and propagating away from the equator. Their burstiness and dispersion of ˜30s/Hz rising out of the 1.5 Hz Pc1 waves are consistent with their identification as EMIC triggered chorus emissions, the first to be reported through in situ observations near the plasmapause. Along with the expected H+ ring current ions seen at higher energies (>300 eV), lower energy ions (300 eV and less) were observed during the most intense EMIC triggered emission events. Nonlinear wave-particle interactions via cyclotron resonance between the ˜2-10 keV H+ ions with temperature anisotropy and the linearly-amplified Pc1 waves are suggested as a possible generation mechanism for the EMIC triggered emissions.

An Arabidopsis mutant showing reduced feedback inhibition of photosynthesis.

PubMed

Van Oosten, J J; Gerbaud, A; Huijser, C; Dijkwel, P P; Chua, N H; Smeekens, S C

1997-11-01

Many plant genes are responsive to sugars but the mechanisms used by plants to sense sugars are unknown. A genetic approach has been used in Arabidopsis to identify genes involved in perception and transduction of sugar signals. For this purpose, an in vivo reporter system was established consisting of the light- and sugar-regulated plastocyanin promoter, fused to the luciferase coding sequence (PC-LUC construct). At the seedling stage, expression of the PC-LUC gene is repressed by sucrose, and a number of sucrose-uncoupled (sun) mutants were selected in which sucrose is unable to repress the activity of the PC promoter. Three mutants have been characterized in more detail. The sugar analog 2-deoxy-D-glucose (2DG) was used to repress whole plant photosynthesis, PC-LUC gene expression and total ribulose-1,5-bisphosphate activity. It was found that the sun6 mutation makes plants unresponsive to these 2DG-induced effects. Moreover, unlike wild-type plants, sun6 mutants are insensitive to elevated levels of glucose in the growth medium. These findings suggest that the SUN6 gene is active in a hexose-activated signal transduction pathway.

Spatiotemporal Variability in Particulate Organic Carbon Export Observed Using Bio-Optical Profiling Floats

NASA Astrophysics Data System (ADS)

Estapa, M. L.

2016-02-01

Autonomous, bio-optical profiling floats are poised to broaden the number and spatiotemporal resolution of observations of the ocean's biological pump. Here, we used multiple optical sensors aboard two bio-optical profiling floats (Navis BGCi, Sea-Bird) deployed in the Sargasso Sea to derive in situ proxies for particulate carbon (PC) flux, sub-mixed layer net community production (NCP) and to drive a model of net primary production (NPP). Profiles were collected at approximately 2-day resolution, and drift-phase PC flux observations were collected at subdaily resolution at a rotating cycle of observation depths between 150 and 1000 m. The magnitudes of NPP, PC flux, and their annually-averaged ratio were generally consistent with observations at the nearby Bermuda Atlantic Timeseries Study (BATS) site. PC flux and the export ratio were enhanced in the autumn as well as in the spring, and varied over short timescales possibly due to the influence of mesoscale eddies. The relatively shallow park depths and short profile cycle lengths allow us to identify ephemeral, subsurface bio-optical features and compare them to measured fluxes and satellite-observed surface properties.

Public awareness of palliative care in Sweden

PubMed Central

Westerlund, Caroline; Benkel, Inger; Fürst, Carl Johan; Molander, Ulla; Rasmussen, Birgit H.; Sauter, Sylvia; Lindqvist, Olav

2018-01-01

Objective: The aim of this study was to investigate the awareness of palliative care (PC) in a general Swedish population. Design: We developed an e-survey based on a similar study conducted in Northern Ireland, consisting of 10 questions. Closed questions were primarily analyzed using descriptive statistics. Open questions were subject to inductive qualitative analysis. Subjects: The study utilized a population sample of 7684 persons aged 18–66, of which 2020 responded, stratified by gender, age and region. Results: Most participants reported ‘no’ (n = 827, 41%) or ‘some’ (n = 863, 43%) awareness of PC. Being female or older were associated with higher levels of awareness, as was a university-level education, working in a healthcare setting and having a friend or family member receiving PC. Most common sources of knowledge were the media, close friends and relatives receiving PC, as well as working in a healthcare setting. Aims of PC were most frequently identified as ‘care before death’, ‘pain relief’, ‘dignity’ and a ‘peaceful death’. The preferred place of care and death was one’s own home. The main barriers to raising awareness about PC were fear, shame and taboo, along with perceived lack of information and/or personal relevance. The term ‘palliative care’ was said to be unfamiliar by many. A number of strategies to enhance awareness and access to PC were suggested, largely reflecting the previously identified barriers. Conclusions: This survey found limited awareness of palliative care in an adult sample of the Swedish general public ≤ 66 years, and points to a more widespread disempowerment surrounding end-of-life issues. PMID:29301481

Flow characteristics in a canine aneurysm model: A comparison of 4D accelerated phase-contrast MR measurements and computational fluid dynamics simulations

PubMed Central

Jiang, Jingfeng; Johnson, Kevin; Valen-Sendstad, Kristian; Mardal, Kent-Andre; Wieben, Oliver; Strother, Charles

2011-01-01

Purpose: Our purpose was to compare quantitatively velocity fields in and around experimental canine aneurysms as measured using an accelerated 4D PC-MR angiography (MRA) method and calculated based on animal-specific CFD simulations. Methods: Two animals with a surgically created bifurcation aneurysm were imaged using an accelerated 4D PC-MRA method. Meshes were created based on the geometries obtained from the PC-MRA and simulations using “subject-specific” pulsatile velocity waveforms and geometries were then solved using a commercial CFD solver. Qualitative visual assessments and quantitative comparisons of the time-resolved velocity fields obtained from the PC-MRA measurements and the CFD simulations were performed using a defined similarity metric combining both angular and magnitude differences of vector fields. Results: PC-MRA and image-based CFD not only yielded visually consistent representations of 3D streamlines in and around both aneurysms, but also showed good agreement with regard to the spatial velocity distributions. The estimated similarity between time-resolved velocity fields from both techniques was reasonably high (mean value >0.60; one being the highest and zero being the lowest). Relative differences in inflow and outflow zones among selected planes were also reasonable (on the order of 10%–20%). The correlation between CFD-calculated and PC-MRA-measured time-averaged wall shear stresses was low (0.22 and 0.31, p < 0.001). Conclusions: In two experimental canine aneurysms, PC-MRA and image-based CFD showed favorable agreement in intra-aneurismal velocity fields. Combining these two complementary techniques likely will further improve the ability to characterize and interpret the complex flow that occurs in human intracranial aneurysms. PMID:22047395

A theoretical framework for analyzing coupled neuronal networks: Application to the olfactory system.

PubMed

Barreiro, Andrea K; Gautam, Shree Hari; Shew, Woodrow L; Ly, Cheng

2017-10-01

Determining how synaptic coupling within and between regions is modulated during sensory processing is an important topic in neuroscience. Electrophysiological recordings provide detailed information about neural spiking but have traditionally been confined to a particular region or layer of cortex. Here we develop new theoretical methods to study interactions between and within two brain regions, based on experimental measurements of spiking activity simultaneously recorded from the two regions. By systematically comparing experimentally-obtained spiking statistics to (efficiently computed) model spike rate statistics, we identify regions in model parameter space that are consistent with the experimental data. We apply our new technique to dual micro-electrode array in vivo recordings from two distinct regions: olfactory bulb (OB) and anterior piriform cortex (PC). Our analysis predicts that: i) inhibition within the afferent region (OB) has to be weaker than the inhibition within PC, ii) excitation from PC to OB is generally stronger than excitation from OB to PC, iii) excitation from PC to OB and inhibition within PC have to both be relatively strong compared to presynaptic inputs from OB. These predictions are validated in a spiking neural network model of the OB-PC pathway that satisfies the many constraints from our experimental data. We find when the derived relationships are violated, the spiking statistics no longer satisfy the constraints from the data. In principle this modeling framework can be adapted to other systems and be used to investigate relationships between other neural attributes besides network connection strengths. Thus, this work can serve as a guide to further investigations into the relationships of various neural attributes within and across different regions during sensory processing.

Glypican-1-antibody-conjugated Gd–Au nanoclusters for FI/MRI dual-modal targeted detection of pancreatic cancer

PubMed Central

Zhu, Huanhuan; Le, Wenjun; Cui, Shaobin; Chen, Xin; Li, Wei; Zhang, Fulei; Huang, Yong; Sh, Donglu; Cui, Zheng; Shao, Chengwei; Chen, Bingdi

2018-01-01

Introduction Pancreatic cancer (PC) has a poor prognosis with high mortality, due to the lack of effective early diagnostic and prognostic tools. Materials and methods In order to target and diagnose PC, we developed a dual-modal imaging probe using Glypican-1 (GPC-1) antibody conjugated with Gd–Au nanoclusters (NCs; Gd-Au-NC-GPC-1). GPC-1 is a type of cell surface heparan sulfate proteoglycan, which is often highly expressed in PC. The probe was successfully prepared with a hydrodynamic diameter ranging from 13.5 to 24.4 nm. Results Spectral characteristics showed absorption at 280 nm and prominent emission at 650 nm. Confocal microscopic imaging showed effective detection of GPC-1 highly expressed PC cells by Gd-Au-NC-GPC-1, which was consistent with flow cytometry results. In vitro relaxivity characterization demonstrated that the r1 value of the probe was 17.722 s−1 mM−1 Gd, which was almost 4 times higher compared with that of Gd-diethylenetriaminepentacetate (DTPA; r1 value =4.6 s−1 mM−1 Gd). Gd-Au-NC-GPC-1 exhibited similar magnetic resonance (MR) signals when compared to Gd-DTPA even at lower Gd concentrations. Much higher MR signals were registered in PC cells (COLO-357) compared with normal cells (293T). Furthermore, Gd-Au-NC-GPC-1 could effectively detect PC cells in vivo by dual-modal fluorescence imaging/magnetic resonance imaging (FI/MRI) at 30 minutes postinjection. In addition, Gd-Au-NC-GPC-1 did not show significant biotoxicity to normal cells at tested concentrations both in vitro and in vivo. Conclusion Gd-Au-NC-GPC-1 has demonstrated to be a promising dual-modal FI/MRI contrast agent for targeted diagnosis of PC. PMID:29750031

Glypican-1-antibody-conjugated Gd-Au nanoclusters for FI/MRI dual-modal targeted detection of pancreatic cancer.

PubMed

Huang, Xin; Fan, Chengqi; Zhu, Huanhuan; Le, Wenjun; Cui, Shaobin; Chen, Xin; Li, Wei; Zhang, Fulei; Huang, Yong; Sh, Donglu; Cui, Zheng; Shao, Chengwei; Chen, Bingdi

2018-01-01

Pancreatic cancer (PC) has a poor prognosis with high mortality, due to the lack of effective early diagnostic and prognostic tools. In order to target and diagnose PC, we developed a dual-modal imaging probe using Glypican-1 (GPC-1) antibody conjugated with Gd-Au nanoclusters (NCs; Gd-Au-NC-GPC-1). GPC-1 is a type of cell surface heparan sulfate proteoglycan, which is often highly expressed in PC. The probe was successfully prepared with a hydrodynamic diameter ranging from 13.5 to 24.4 nm. Spectral characteristics showed absorption at 280 nm and prominent emission at 650 nm. Confocal microscopic imaging showed effective detection of GPC-1 highly expressed PC cells by Gd-Au-NC-GPC-1, which was consistent with flow cytometry results. In vitro relaxivity characterization demonstrated that the r1 value of the probe was 17.722 s -1 mM -1 Gd, which was almost 4 times higher compared with that of Gd-diethylenetriaminepentacetate (DTPA; r1 value =4.6 s -1 mM -1 Gd). Gd-Au-NC-GPC-1 exhibited similar magnetic resonance (MR) signals when compared to Gd-DTPA even at lower Gd concentrations. Much higher MR signals were registered in PC cells (COLO-357) compared with normal cells (293T). Furthermore, Gd-Au-NC-GPC-1 could effectively detect PC cells in vivo by dual-modal fluorescence imaging/magnetic resonance imaging (FI/MRI) at 30 minutes postinjection. In addition, Gd-Au-NC-GPC-1 did not show significant biotoxicity to normal cells at tested concentrations both in vitro and in vivo. Gd-Au-NC-GPC-1 has demonstrated to be a promising dual-modal FI/MRI contrast agent for targeted diagnosis of PC.

ROCSAT and HF Doppler sounder observations of the DP2-type electric field during the global Pc5 magnetic pulsation event

NASA Astrophysics Data System (ADS)

Hashimoto, K. K.; Kikuchi, T.; Nagatsuma, T.; Tomizawa, I.

2016-12-01

During the stormtime Pc5 magnetic pulsations on 31 October 2003, we detected large amplitude oscillations in the ionospheric electric field with the HF Doppler sounders at midlatitude for 10 hours from 11 to 21 LT. Similar oscillations were recorded on the magnetometer data at high-to-equatorial latitudes with significant amplitude enhancement at the dayside equator. We deduced the equatorial electrojet (EEJ) by subtracting the low latitude Pc5 from the equatorial Pc5 and found that the midlatitude electric field (EF) is well correlated with the EEJ with correlation coefficients (0.80-0.95) and that the EEJ to EF ratio reached maximum at 11 LT and dramatically decreased until 18 LT in a function of cos0.6(solar zenith angle). With these observations, we suggest that the midlatitude electric field (EF) is associated with the DP2 type ionospheric currents transmitted from high latitude to the equator. It is to be noted that the EF is well correlated with the EEJ during the night after 18 LT, indicating that the Pc5 electric field is so strong as to drive equatorial electrojet in the nighttime ionosphere. Using the electric field measured by ROCSAT-1/IPEI, we confirmed that the Pc5 electric field in the mid- and low-latitude ionosphere is comparable to or even stronger than those observed by the HF Doppler sounders. High correlations between the ground- and satellite-based observations over 15 minutes indicate that the Pc5 electric field distribute uniform over 6500 km along the ROCSAT orbit which is consistent with the large-scale DP2 electric field.

Changes in phosphatidylcholine fatty acid composition are associated with altered skeletal muscle insulin responsiveness in normal man.

PubMed

Clore, J N; Harris, P A; Li, J; Azzam, A; Gill, R; Zuelzer, W; Rizzo, W B; Blackard, W G

2000-02-01

The fatty acid composition of skeletal muscle cell membrane phospholipids (PLs) is known to influence insulin responsiveness in man. We have recently shown that the fatty acid composition of phosphatidylcholine (PC), and not phosphatidylethanolamine (PE), from skeletal muscle membranes is of particular importance in this relationship. Efforts to alter the PL fatty acid composition in animal models have demonstrated induction of insulin resistance. However, it has been more difficult to determine if changes in insulin sensitivity are associated with changes in the skeletal muscle membrane fatty acid composition of PL in man. Using nicotinic acid (NA), an agent known to induce insulin resistance in man, 9 normal subjects were studied before and after treatment for 1 month. Skeletal muscle membrane fatty acid composition of PC and PE from biopsies of vastus lateralis was correlated with insulin responsiveness using a 3-step hyperinsulinemic-euglycemic clamp. Treatment with NA was associated with a 25% increase in the half-maximal insulin concentration ([ED50] 52.0 +/- 7.5 to 64.6 +/- 9.0 microU/mL, P < .05), consistent with decreased peripheral insulin sensitivity. Significant changes in the fatty acid composition of PC, but not PE, were also observed after NA administration. An increase in the percentage of 16:0 (21% +/- 0.3% to 21.7% +/- 0.4%, P < .05) and decreases in 18:0 (6.2% +/- 0.5% to 5.1% +/- 0.4%, P = .01), long-chain n-3 fatty acids (1.7% +/- 0.2% to 1.4% +/- 0.1%, P < .01), and total polyunsaturated fatty acids ([PUFAs] 8.7% +/- 0.8% to 8.0% +/- 0.8%, P < .05) are consistent with a decrease in fatty acid length and unsaturation in PC following NA administration. The change in ED50 was significantly correlated with the change in PUFAs (r = -.65, P < .05). These studies suggest that the induction of insulin resistance with NA is associated with changes in the fatty acid composition of PC in man.

In vivo biomarker expression patterns are preserved in 3D cultures of Prostate Cancer

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

Windus, Louisa C.E.; Kiss, Debra L.; Glover, Tristan

2012-11-15

Here we report that Prostate Cancer (PCa) cell-lines DU145, PC3, LNCaP and RWPE-1 grown in 3D matrices in contrast to conventional 2D monolayers, display distinct differences in cell morphology, proliferation and expression of important biomarker proteins associated with cancer progression. Consistent with in vivo growth rates, in 3D cultures, all PCa cell-lines were found to proliferate at significantly lower rates in comparison to their 2D counterparts. Moreover, when grown in a 3D matrix, metastatic PC3 cell-lines were found to mimic more precisely protein expression patterns of metastatic tumour formation as found in vivo. In comparison to the prostate epithelial cell-linemore » RWPE-1, metastatic PC3 cell-lines exhibited a down-regulation of E-cadherin and {alpha}6 integrin expression and an up-regulation of N-cadherin, Vimentin and {beta}1 integrin expression and re-expressed non-transcriptionally active AR. In comparison to the non-invasive LNCaP cell-lines, PC3 cells were found to have an up-regulation of chemokine receptor CXCR4, consistent with a metastatic phenotype. In 2D cultures, there was little distinction in protein expression between metastatic, non-invasive and epithelial cells. These results suggest that 3D cultures are more representative of in vivo morphology and may serve as a more biologically relevant model in the drug discovery pipeline. -- Highlights: Black-Right-Pointing-Pointer We developed and optimised 3D culturing techniques for Prostate Cancer cell-lines. Black-Right-Pointing-Pointer We investigated biomarker expression in 2D versus 3D culture techniques. Black-Right-Pointing-Pointer Metastatic PC3 cells re-expressed non-transcriptionally active androgen receptor. Black-Right-Pointing-Pointer Metastatic PCa cell lines retain in vivo-like antigenic profiles in 3D cultures.« less

Carbon flux from bio-optical profiling floats: Calibrating transmissometers for use as optical sediment traps

NASA Astrophysics Data System (ADS)

Estapa, Meg; Durkin, Colleen; Buesseler, Ken; Johnson, Rod; Feen, Melanie

2017-02-01

Our mechanistic understanding of the processes controlling the ocean's biological pump is limited, in part, by our lack of observational data at appropriate timescales. The "optical sediment trap" (OST) technique utilizes a transmissometer on a quasi-Lagrangian platform to collect sedimenting particles. This method could help fill the observational gap by providing autonomous measurements of particulate carbon (PC) flux in the upper mesopelagic ocean at high spatiotemporal resolution. Here, we used a combination of field measurements and laboratory experiments to test hydrodynamic and zooplankton-swimmer effects on the OST method, and we quantitatively calibrated this method against PC flux measured directly in same-platform, neutrally buoyant sediment traps (NBSTs) during 5 monthly cruises at the Bermuda Atlantic Time-series Study (BATS) site. We found a well-correlated, positive relationship (R2=0.66, n=15) between the OST proxy, and the PC flux measured directly using NBSTs. Laboratory tests showed that scattering of light from multiple particles between the source and detector was unlikely to affect OST proxy results. We found that the carbon-specific attenuance of sinking particles was larger than literature values for smaller, suspended particles in the ocean, and consistent with variable carbon: size relationships reported in the literature for sinking particles. We also found evidence for variability in PC flux at high spatiotemporal resolution. Our results are consistent with the literature on particle carbon content and optical properties in the ocean, and support more widespread use of the OST proxy, with proper site-specific and platform-specific calibration, to better understand variability in the ocean biological pump.

Dynamic contrast enhanced-magnetic resonance imaging (DCE-MRI) for the assessment of Pc 4-sensitized photodynamic therapy of a U87-derived glioma model in the athymic nude rat

NASA Astrophysics Data System (ADS)

Anka, Ali; Thompson, Paul; Mott, Eric; Sharma, Rahul; Zhang, Ruozhen; Cross, Nathan; Sun, Jiayang; Flask, Chris A.; Oleinick, Nancy L.; Dean, David

2010-02-01

Introduction: Dynamic Contrast-Enhanced-Magnetic Resonance Imaging (DCE-MRI) may provide a means of tracking the outcome of Pc 4-sensitized photodynamic therapy (PDT) in deeply placed lesions (e.g., brain tumors). We previously determined that 150 μL of gadolinium (Gd-DTPA) produces optimal enhancement of U87-derived intracerebral tumors in an athymic nude rat glioma model. We wish to determine how consistently DCE-MRI enhancement will detect an increase in Gd-enhancement of these tumors following Pc 4-PDT. Methods: We injected 2.5 x 105 U87 cells into the brains of 6 athymic nude rats. After 7-8 days pre-Pc 4 PDT peri-tumor DCE-MRI images were acquired on a 7.0T microMRI scanner before and after administration of 150 μL Gd. DCE-MRI scans were repeated on Days 11, 12, and 13 following Pc 4-PDT (Day 8 or 9). Results: Useful DCE-MRI data were obtained for these animals before and after Pc 4- PDT. In the pre-Pc 4-PDT DCE-MRI scans an average normalized peak Gd enhancement was observed in tumor tissue that was 1.297 times greater than baseline (0.035 Standard Error [SE]). The average normalized peak Gd enhancement in the tumor tissue in the scan following PDT (Day 11) was 1.537 times greater than baseline (0.036 SE), a statistically significant increase in enhancement (p = 0.00584) over the pre-PDT level. Discussion: A 150 μL Gd dose appears to provide an unambiguous increase in signal indicating Pc 4-PDT-induced necrosis of the U87-derived tumor. Our DCEMRI protocol may allow the development of a clinically robust, unambiguous, non-invasive technique for the assessment of PDT outcome.

Silver nanoparticle protein corona composition in cell culture media.

PubMed

Shannahan, Jonathan H; Lai, Xianyin; Ke, Pu Chun; Podila, Ramakrishna; Brown, Jared M; Witzmann, Frank A

2013-01-01

The potential applications of nanomaterials as drug delivery systems and in other products continue to expand. Upon introduction into physiological environments and driven by energetics, nanomaterials readily associate proteins forming a protein corona (PC) on their surface. This PC influences the nanomaterial's surface characteristics and may impact their interaction with cells. To determine the biological impact of nanomaterial exposure as well as nanotherapeutic applications, it is necessary to understand PC formation. Utilizing a label-free mass spectrometry-based proteomics approach, we examined the composition of the PC for a set of four silver nanoparticles (AgNPs) including citrate-stabilized and polyvinlypyrrolidone-stabilized (PVP) colloidal silver (20 or 110 nm diameter). To simulate cell culture conditions, AgNPs were incubated for 1 h in Dulbecco's Modified Eagle Medium supplemented with 10% fetal bovine serum, washed, coronal proteins solubilized, and proteins identified and quantified by label-free LC-MS/MS. To determine which attributes influence PC formation, the AgNPs were characterized in both water and cell culture media with 10% FBS. All AgNPs associated a common subset of 11 proteins including albumin, apolipoproteins, keratins, and other serum proteins. 110 nm citrate- and PVP-stabilized AgNPs were found to bind the greatest number of proteins (79 and 85 respectively) compared to 20 nm citrate- and PVP-stabilized AgNPs (45 and 48 respectively), suggesting a difference in PC formation based on surface curvature. While no relationships were found for other protein parameters (isoelectric point or aliphatic index), the PC on 20 nm AgNPs (PVP and citrate) consisted of more hydrophobic proteins compared to 110 nm AgNPs implying that this class of proteins are more receptive to curvature-induced folding and crowding in exchange for an increased hydration in the aqueous environment. These observations demonstrate the significance of electrostatic and hydrophobic interactions in the formation of the PC which may have broad biological and toxicological implications.

Improved Photodynamic Efficacy of Zn(II) Phthalocyanines via Glycerol Substitution

PubMed Central

Chin, Yunni; Lim, Siang Hui; Zorlu, Yunus; Ahsen, Vefa; Kiew, Lik Voon; Chung, Lip Yong; Dumoulin, Fabienne; Lee, Hong Boon

2014-01-01

Phthalocyanines are excellent photosensitizers for photodynamic therapy as they have strong absorbance in the near infra-red region which is most relevant for in vivo activation in deeper tissular regions. However, most phthalocyanines present two major challenges, ie, a strong tendency to aggregate and low water-solubility, limiting their effective usage clinically. In the present study, we evaluated the potential enhancement capability of glycerol substitution on the photodynamic properties of zinc (II) phthalocyanines (ZnPc). Three glycerol substituted ZnPc, 1–3, (tetra peripherally, tetra non-peripherally and mono iodinated tri non-peripherally respectively) were evaluated in terms of their spectroscopic properties, rate of singlet oxygen generation, partition coefficient (log P), intracellular uptake, photo-induced cytotoxicity and vascular occlusion efficiency. Tetrasulfonated ZnPc (ZnPcS4) was included as a reference compound. Here, we showed that 1–3 exhibited 10–100 nm red-shifted absorption peaks with higher molar absorptivity, and at least two-fold greater singlet oxygen generation rates compared to ZnPcS4. Meanwhile, phthalocyanines 1 and 2 showed more hydrophilic log P values than 3 consistent with the number of glycerol attachments but 3 was most readily taken up by cells compared to the rest. Both phthalocyanines 2 and 3 exhibited potent phototoxicity against MCF-7, HCT-116 and HSC-2 cancer cell-lines with IC50 ranging 2.8–3.2 µM and 0.04–0.06 µM respectively, while 1 and ZnPcS4 (up to 100 µM) failed to yield determinable IC50 values. In terms of vascular occlusion efficiency, phthalocyanine 3 showed better effects than 2 by causing total occlusion of vessels with diameter <70 µm of the chorioallantoic membrane. Meanwhile, no detectable vascular occlusion was observed for ZnPcS4 with treatment under similar experimental conditions. These findings provide evidence that glycerol substitution, in particular in structures 2 and 3, is able to improve the photodynamic properties of ZnPc. PMID:24840576

Improved photodynamic efficacy of Zn(II) phthalocyanines via glycerol substitution.

PubMed

Chin, Yunni; Lim, Siang Hui; Zorlu, Yunus; Ahsen, Vefa; Kiew, Lik Voon; Chung, Lip Yong; Dumoulin, Fabienne; Lee, Hong Boon

2014-01-01

Phthalocyanines are excellent photosensitizers for photodynamic therapy as they have strong absorbance in the near infra-red region which is most relevant for in vivo activation in deeper tissular regions. However, most phthalocyanines present two major challenges, ie, a strong tendency to aggregate and low water-solubility, limiting their effective usage clinically. In the present study, we evaluated the potential enhancement capability of glycerol substitution on the photodynamic properties of zinc (II) phthalocyanines (ZnPc). Three glycerol substituted ZnPc, 1-3, (tetra peripherally, tetra non-peripherally and mono iodinated tri non-peripherally respectively) were evaluated in terms of their spectroscopic properties, rate of singlet oxygen generation, partition coefficient (log P), intracellular uptake, photo-induced cytotoxicity and vascular occlusion efficiency. Tetrasulfonated ZnPc (ZnPcS4) was included as a reference compound. Here, we showed that 1-3 exhibited 10-100 nm red-shifted absorption peaks with higher molar absorptivity, and at least two-fold greater singlet oxygen generation rates compared to ZnPcS4. Meanwhile, phthalocyanines 1 and 2 showed more hydrophilic log P values than 3 consistent with the number of glycerol attachments but 3 was most readily taken up by cells compared to the rest. Both phthalocyanines 2 and 3 exhibited potent phototoxicity against MCF-7, HCT-116 and HSC-2 cancer cell-lines with IC50 ranging 2.8-3.2 µM and 0.04-0.06 µM respectively, while 1 and ZnPcS4 (up to 100 µM) failed to yield determinable IC50 values. In terms of vascular occlusion efficiency, phthalocyanine 3 showed better effects than 2 by causing total occlusion of vessels with diameter <70 µm of the chorioallantoic membrane. Meanwhile, no detectable vascular occlusion was observed for ZnPcS4 with treatment under similar experimental conditions. These findings provide evidence that glycerol substitution, in particular in structures 2 and 3, is able to improve the photodynamic properties of ZnPc.

Structured mating: Patterns and implications

PubMed Central

Sebro, Ronnie; Peloso, Gina M.; Risch, Neil J.

2017-01-01

Genetic similarity of spouses can reflect factors influencing mate choice, such as physical/behavioral characteristics, and patterns of social endogamy. Spouse correlations for both genetic ancestry and measured traits may impact genotype distributions (Hardy Weinberg and linkage equilibrium), and therefore genetic association studies. Here we evaluate white spouse-pairs from the Framingham Heart Study (FHS) original and offspring cohorts (N = 124 and 755, respectively) to explore spousal genetic similarity and its consequences. Two principal components (PCs) of the genome-wide association (GWA) data were identified, with the first (PC1) delineating clines of Northern/Western to Southern European ancestry and the second (PC2) delineating clines of Ashkenazi Jewish ancestry. In the original (older) cohort, there was a striking positive correlation between the spouses in PC1 (r = 0.73, P = 3x10-22) and also for PC2 (r = 0.80, P = 7x10-29). In the offspring cohort, the spouse correlations were lower but still highly significant for PC1 (r = 0.38, P = 7x10-28) and for PC2 (r = 0.45, P = 2x10-39). We observed significant Hardy-Weinberg disequilibrium for single nucleotide polymorphisms (SNPs) loading heavily on PC1 and PC2 across 3 generations, and also significant linkage disequilibrium between unlinked SNPs; both decreased with time, consistent with reduced ancestral endogamy over generations and congruent with theoretical calculations. Ignoring ancestry, estimates of spouse kinship have a mean significantly greater than 0, and more so in the earlier generations. Adjusting kinship estimates for genetic ancestry through the use of PCs led to a mean spouse kinship not different from 0, demonstrating that spouse genetic similarity could be fully attributed to ancestral assortative mating. These findings also have significance for studies of heritability that are based on distantly related individuals (kinship less than 0.05), as we also demonstrate the poor correlation of kinship estimates in that range when ancestry is or is not taken into account. PMID:28384154

Genetic and Functional Assessment of the Role of the rs13431652-A and rs573225-A Alleles in the G6PC2 Promoter That Are Strongly Associated With Elevated Fasting Glucose Levels

PubMed Central

Bouatia-Naji, Nabila; Bonnefond, Amélie; Baerenwald, Devin A.; Marchand, Marion; Bugliani, Marco; Marchetti, Piero; Pattou, François; Printz, Richard L.; Flemming, Brian P.; Umunakwe, Obi C.; Conley, Nicholas L.; Vaxillaire, Martine; Lantieri, Olivier; Balkau, Beverley; Marre, Michel; Lévy-Marchal, Claire; Elliott, Paul; Jarvelin, Marjo-Riitta; Meyre, David; Dina, Christian; Oeser, James K.; Froguel, Philippe; O'Brien, Richard M.

2010-01-01

OBJECTIVE Genome-wide association studies have identified a single nucleotide polymorphism (SNP), rs560887, located in a G6PC2 intron that is highly correlated with variations in fasting plasma glucose (FPG). G6PC2 encodes an islet-specific glucose-6-phosphatase catalytic subunit. This study examines the contribution of two G6PC2 promoter SNPs, rs13431652 and rs573225, to the association signal. RESEARCH DESIGN AND METHODS We genotyped 9,532 normal FPG participants (FPG <6.1 mmol/l) for three G6PC2 SNPs, rs13431652 (distal promoter), rs573225 (proximal promoter), rs560887 (3rd intron). We used regression analyses adjusted for age, sex, and BMI to assess the association with FPG and haplotype analyses to assess comparative SNP contributions. Fusion gene and gel retardation analyses characterized the effect of rs13431652 and rs573225 on G6PC2 promoter activity and transcription factor binding. RESULTS Genetic analyses provide evidence for a strong contribution of the promoter SNPs to FPG variability at the G6PC2 locus (rs13431652: β = 0.075, P = 3.6 × 10−35; rs573225 β = 0.073 P = 3.6 × 10−34), in addition to rs560887 (β = 0.071, P = 1.2 × 10−31). The rs13431652-A and rs573225-A alleles promote increased NF-Y and Foxa2 binding, respectively. The rs13431652-A allele is associated with increased FPG and elevated promoter activity, consistent with the function of G6PC2 in pancreatic islets. In contrast, the rs573225-A allele is associated with elevated FPG but reduced promoter activity. CONCLUSIONS Genetic and in situ functional data support a potential role for rs13431652, but not rs573225, as a causative SNP linking G6PC2 to variations in FPG, though a causative role for rs573225 in vivo cannot be ruled out. PMID:20622168

Barriers to and facilitators for implementing quality improvements in palliative care - results from a qualitative interview study in Norway.

PubMed

Sommerbakk, Ragni; Haugen, Dagny Faksvåg; Tjora, Aksel; Kaasa, Stein; Hjermstad, Marianne Jensen

2016-07-15

Implementation of quality improvements in palliative care (PC) is challenging, and detailed knowledge about factors that may facilitate or hinder implementation is essential for success. One part of the EU-funded IMPACT project (IMplementation of quality indicators in PAlliative Care sTudy) aiming to increase the knowledge base, was to conduct national studies in PC services. This study aims to identify factors perceived as barriers or facilitators for improving PC in cancer and dementia settings in Norway. Individual, dual-participant and focus group interviews were conducted with 20 employees working in different health care services in Norway: two hospitals, one nursing home, and two local medical centers. Thematic analysis with a combined inductive and theoretical approach was applied. Barriers and facilitators were connected to (1) the innovation (e.g. credibility, advantage, accessibility, attractiveness); (2) the individual professional (e.g. motivation, PC expertise, confidence); (3) the patient (e.g. compliance); (4) the social context (e.g. leadership, culture of change, face-to-face contact); (5) the organizational context (e.g. resources, structures/facilities, expertise); (6) the political and economic context (e.g. policy, legislation, financial arrangements) and (7) the implementation strategy (e.g. educational, meetings, reminders). Four barriers that were particular to PC were identified: the poor general condition of patients in need of PC, symptom assessment tools that were not validated in all patient groups, lack of PC expertise and changes perceived to be at odds with staff's philosophy of care. When planning an improvement project in PC, services should pay particular attention to factors associated with their chosen implementation strategy. Leaders should also involve staff early in the improvement process, ensure that they have the necessary training in PC and that the change is consistent with the staff's philosophy of care. An important consideration when implementing a symptom assessment tool is whether or not the tool has been validated for the relevant patient group, and to what degree patients need to be involved when using the tool.

A systematic review and meta-analysis of the relative efficacy and safety of treatment regimens for HIV-associated cerebral toxoplasmosis: is trimethoprim-sulfamethoxazole a real option?

PubMed

Hernandez, A V; Thota, P; Pellegrino, D; Pasupuleti, V; Benites-Zapata, V A; Deshpande, A; Penalva de Oliveira, A C; Vidal, J E

2017-02-01

The objective of this study was to perform a systematic review and meta-analysis of the literature to evaluate the efficacy and safety of therapies for cerebral toxoplasmosis in HIV-infected adults. The pyrimethamine plus sulfadiazine (P-S) combination is considered the mainstay therapy for cerebral toxoplasmosis and pyrimethamine plus clindamycin (P-C) is the most common alternative treatment. Although trimethoprim-sulfamethoxazole (TMP-SMX) has potential advantages, its use is infrequent. We searched PubMed and four other databases to identify randomized controlled trials (RCTs) and cohort studies. Two independent reviewers searched the databases, identified studies and extracted data. Risk ratios (RRs) were pooled across studies using random-effects models. Nine studies were included (five RCTs, three retrospective cohort studies and one prospective cohort study). In comparison to P-S, treatment with P-C or TMP-SMX was associated with similar rates of partial or complete clinical response [P-C: RR 0.87; 95% confidence interval (CI) 0.70-1.08; TMP-SMX: RR 0.97; 95% CI 0.78-1.21], radiological response (P-C: RR 0.92; 95% CI 0.82-1.03), skin rash (P-C: RR 0.81; 95% CI 0.56-1.17; TMP-SMX: RR 0.17; 95% CI 0.02-1.29), gastrointestinal impairment (P-C: RR 5.16; 95% CI 0.66-40.11), and drug discontinuation because of adverse events (P-C: RR 0.32; 95% CI 0.07-1.47). Liver impairment was more frequent with P-S than P-C (P-C vs. P-S: RR 0.48; 95% CI 0.24-0.97). The current evidence fails to identify a superior regimen in terms of relative efficacy or safety for the treatment of HIV-associated cerebral toxoplasmosis. Use of TMP-SMX as preferred treatment may be consistent with the available evidence and other real-world considerations. Larger comparative studies are needed. © 2016 British HIV Association.

Intercalating dyes for enhanced contrast in second-harmonic generation imaging of protein crystals

PubMed Central

Newman, Justin A.; Scarborough, Nicole M.; Pogranichniy, Nicholas R.; Shrestha, Rashmi K.; Closser, Richard G.; Das, Chittaranjan; Simpson, Garth J.

2015-01-01

The second-harmonic generation (SHG) activity of protein crystals was found to be enhanced by up to ∼1000-fold by the intercalation of SHG phores within the crystal lattice. Unlike the intercalation of fluorophores, the SHG phores produced no significant background SHG from solvated dye or from dye intercalated into amorphous aggregates. The polarization-dependent SHG is consistent with the chromophores adopting the symmetry of the crystal lattice. In addition, the degree of enhancement for different symmetries of dyes is consistent with theoretical predictions based on the molecular nonlinear optical response. Kinetics studies indicate that intercalation arises over a timeframe of several minutes in lysozyme, with detectable enhancements within seconds. These results provide a potential means to increase the overall diversity of protein crystals and crystal sizes amenable to characterization by SHG microscopy. PMID:26143918

Self-consistent phonon theory of the crystallization and elasticity of attractive hard spheres.

PubMed

Shin, Homin; Schweizer, Kenneth S

2013-02-28

We propose an Einstein-solid, self-consistent phonon theory for the crystal phase of hard spheres that interact via short-range attractions. The approach is first tested against the known behavior of hard spheres, and then applied to homogeneous particles that interact via short-range square well attractions and the Baxter adhesive hard sphere model. Given the crystal symmetry, packing fraction, and strength and range of attractive interactions, an effective harmonic potential experienced by a particle confined to its Wigner-Seitz cell and corresponding mean square vibrational amplitude are self-consistently calculated. The crystal free energy is then computed and, using separate information about the fluid phase free energy, phase diagrams constructed, including a first-order solid-solid phase transition and its associated critical point. The simple theory qualitatively captures all the many distinctive features of the phase diagram (critical and triple point, crystal-fluid re-entrancy, low-density coexistence curve) as a function of attraction range, and overall is in good semi-quantitative agreement with simulation. Knowledge of the particle localization length allows the crystal shear modulus to be estimated based on elementary ideas. Excellent predictions are obtained for the hard sphere crystal. Expanded and condensed face-centered cubic crystals are found to have qualitatively different elastic responses to varying attraction strength or temperature. As temperature increases, the expanded entropic solid stiffens, while the energy-controlled, fully-bonded dense solid softens.

Simultaneous real-time data collection methods

NASA Technical Reports Server (NTRS)

Klincsek, Thomas

1992-01-01

This paper describes the development of electronic test equipment which executes, supervises, and reports on various tests. This validation process uses computers to analyze test results and report conclusions. The test equipment consists of an electronics component and the data collection and reporting unit. The PC software, display screens, and real-time data-base are described. Pass-fail procedures and data replay are discussed. The OS2 operating system and Presentation Manager user interface system were used to create a highly interactive automated system. The system outputs are hardcopy printouts and MS DOS format files which may be used as input for other PC programs.

Co-polymerization of methyl methacrylate and styrene via surfactant-free emulsion polymerization, as a potential material for photonic crystal application

NASA Astrophysics Data System (ADS)

Kassim, Syara; Zahari, Siti Balqis; Tahrin, Rabiatul Addawiyah Azwa; Harun, Noor Aniza

2017-09-01

Photonic crystals are being the great interest of researcher to studies due to a variety of potential application for the interaction of light including the solar cells, optical sensors and paints. In order to evaluate the fabrication of photonic crystals thin film, a free-emulsifier emulsion copolymerization of styrene and methyl methacrylate was carried out. By using the self -assembly approach, this method offers the opportunity to produce crystalline polymer sphere in more ease operation, low cost and environmental friendly. The influences of the mixing ratio of monomer and amount of initiators were studied. In advance, the presence of styrene as co-monomer had improved the thermal degradation of polymer methyl methacrylate. While in changing the mixing ratio of styrene and methyl methacrylate resulted in particle size of the sphere. The size of polymer particles slightly increased on increasing volume of styrene monomer ratio. This occurred because the properties of styrene in water where it sparingly soluble and lead to coagulation of particles. This simple, yet effective method for preparing functional complex 3D structures has the potential to be used generically to fabricate a variety of functional porous 3D structures that could find application not only in new or improved photonic crystal (PC) devices but also in areas such as catalysis, solar cell, separation, fuel cells technology, microelectronics and optoelectronics.

Channeling, Volume Reection and Gamma Emission Using 14GeV Electrons in Bent Silicon Crystals

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

Benson, Brandon

2015-08-14

High energy electrons can be deflected with very tight bending radius using a bent silicon crystal. This produces gamma radiation. As these crystals can be thin, a series of bent silicon crystals with alternating direction has the potential to produce coherent gamma radiation with reasonable energy of the driving electron beam. Such an electron crystal undulator offers the prospect for higher energy radiation at lower cost than current methods. Permanent magnetic undulators like LCLS at SLAC National Accelerator Laboratory are expensive and very large (about 100 m in case of the LCLS undulator). Silicon crystals are inexpensive and compact whenmore » compared to the large magnetic undulators. Additionally, such a high energy coherent light source could be used for probing through materials currently impenetrable by x-rays. In this work we present the experimental data and analysis of experiment T523 conducted at SLAC National Accelerator Laboratory. We collected the spectrum of gamma ray emission from 14 GeV electrons on a bent silicon crystal counting single photons. We also investigated the dynamics of electron motion in the crystal i.e. processes of channeling and volume reflection at 14 GeV, extending and building off previous work. Our single photon spectrum for the amorphous crystal orientation is consistent with bremsstrahlung radiation and the volume reflection crystal orientation shows a trend consistent with synchrotron radiation at a critical energy of 740 MeV. We observe that in these two cases the data are consistent, but we make no further claims because of statistical limitations. We also extended the known energy range of electron crystal dechanneling length and channeling efficiency to 14 GeV.« less

A New PC and LabVIEW Package Based System for Electrochemical Investigations

PubMed Central

Stević, Zoran; Andjelković, Zoran; Antić, Dejan

2008-01-01

The paper describes a new PC and LabVIEW software package based system for electrochemical research. An overview of well known electrochemical methods, such as potential measurements, galvanostatic and potentiostatic method, cyclic voltammetry and EIS is given. Electrochemical impedance spectroscopy has been adapted for systems containing large capacitances. For signal generation and recording of the response of investigated electrochemical cell, a measurement and control system was developed, based on a PC P4. The rest of the hardware consists of a commercially available AD-DA converter and an external interface for analog signal processing. The interface is a result of authors own research. The software platform for desired measurement methods is LabVIEW 8.2 package, which is regarded as a high standard in the area of modern virtual instruments. The developed system was adjusted, tested and compared with commercially available system and ORCAD simulation. PMID:27879794

Pulsar Polar Cap Heating and Surface Thermal X-ray Emission. 1; Curvature Radiation Pair Fronts

NASA Technical Reports Server (NTRS)

Harding, Alice K.; Muslimov, Alexander G.; White, Nicholas E. (Technical Monitor)

2002-01-01

We investigate the effect of pulsar polar cap (PC) heating produced by positrons returning from the upper pair formation front. Our calculations are based on a self-consistent treatment of the pair dynamics and the effect of electric field screening by the returning positrons. We calculate the resultant X-ray luminosities and discuss the dependence of the PC heating efficiencies on pulsar parameters, such as characteristic spin-down age, spin period, and surface magnetic field strength. In this study we concentrate on the regime where the pairs are produced in a magnetic field by curvature photons emitted by accelerating electrons. Our theoretical results are not in conflict with the available observational x-ray data and suggest that the effect of PC heating should significantly contribute to the thermal x-ray fluxes from middle-aged and old pulsars. The implications for current and future x-ray observations of pulsars are briefly outlined.

Cygnus X-2 - Neutron star or degenerate dwarf?

NASA Technical Reports Server (NTRS)

Mcclintock, J. E.; Remillard, R. A.; Petro, L. D.; Hammerschlag-Hensberge, G.; Proffitt, C. R.

1984-01-01

Some conflicting models have been proposed for Cyg X-2: a degenerate dwarf model which predicts a distance of 250 + or 50 pc; and a neutron star model which implies a distance of about 8000 pc. Based on a reddening study, it is found that the distance to Cyg X-2 is greater than 1100 pc, which rules strongly against the degenerate dwarf model. This conclusion is based on observations of the 2200 A feature in the spectrum of Cyg X-2 made with the International Ultraviolet Explorer (IUE), and UBV and spectroscopic observations of 38 field stars. For the reddening of Cyg X-2 values of E(B-V) = 0.40 + or - 0.07 (1 sigma) are found and are consistent with the reddening to infinity in that direction inferred from radio data. Consequently, Cyg X-2 may be located in the halo at about 8 kpc as proposed in 1979 by Cowley, Crampton, and Hutchings.

[The development of a respiration and temperature monitor].

PubMed

Du, X; Wu, B; Liu, Y; He, Q; Xiao, J

2001-12-01

This paper introduces the design of a monitoring system to measure the respiration and temperature of a body with an 8Xc196 single-chip microcomputer. This system can measure and display the respiration wave, respiration frequency and the body temperature in real-time with a liquid crystal display (LCD) and give an alarm when the parameters are beyond the normal scope. In addition, this device can provide a 24 hours trend graph of the respiration frequency and the body temperature parameters measured. Data can also be exchanged through serial communication interfaces (RS232) between the PC and the monitor.

Device for diagnosis and treatment of impairments on binocular vision and stereopsis

NASA Astrophysics Data System (ADS)

Bahn, Jieun; Choi, Yong-Jin; Son, Jung-Young; Kodratiev, N. V.; Elkhov, Victor A.; Ovechkis, Yuri N.; Chung, Chan-sup

2001-06-01

Strabismus and amblyopia are two main impairments of our visual system, which are responsible for the loss of stereovision. A device is developed for diagnosis and treatment of strabismus and amblyopia, and for training and developing stereopsis. This device is composed of a liquid crystal glasses (LCG), electronics for driving LCG and synchronizing with an IBM PC, and a special software. The software contains specially designed patterns and graphics for enabling to train and develop stereopsis, and do objective measurement of some stereoscopic vision parameters such as horizontal and vertical phoria, fusion, fixation disparity, and stereoscopic visual threshold.

Optical properties of opal photonic crystals

NASA Astrophysics Data System (ADS)

Eradat-Oskouei, Nayer

2001-10-01

Photonic crystals (PC) are a class of artificial structures with a periodic dielectric function in one, two, or three dimensions, in which the propagation of electromagnetic waves within a certain frequency band is forbidden. This forbidden frequency band has been dubbed photonic band gap (PBG). The position, width, depth, and shape of the PBG strongly depend on the periodicity, symmetry properties, dielectric constant contrast, and internal lattice structure of the unit cell. There is a common belief that PCs will perform many functions with light that ordinary crystals do with electrons. At the same time, PCs are of great promise to become a laboratory for testing fundamental processes involving interactions of radiation with matter in novel conditions. We have studied the optical properties of opal PCs that are infiltrated with metals, laser dyes, π-conjugated polymers, and J-aggregates. Opals are self-assembled structures of silica (SiO2) spheres mostly packed in a face centered cubic (fcc) lattice. Our research is summarized in the following six chapters. Chapter 1 is a review on the concepts related to PBG and PC, eigenvalue problem of electromagnetism, material systems that exhibit PBG. Chapter 2 covers all the fabrication and measurement techniques including angle resolved reflectivity, transmission, photoluminescence, photo-induced absorption, and coherent backscattering. Chapter 3 focuses on the relationship between a polaritonic gap and a photonic stop-band when they resonantly coexist in the same structure. Infiltration of opal with polarizable molecules combines the polaritonic and Bragg diffractive effects. The experimental results on reflectivity and its dependence on the impinging angle and concentration of the polarizable medium are in agreement with the theoretical calculations. In Chapter 4, the optical studies of three-dimensional metallic mesh composites are reported. Photonic and electronic properties of these PCs strongly depend on their geometry. Dramatic differences in the reflectivity spectra of two kinds of metallic structures, with network or cermet topologies, were observed. Bragg diffraction occurs from both topologies. In addition, highly interconnected metallic PC structures showed about one order of magnitude decrease in the effective plasma frequency. These properties may be used to create transparent metals. Coherent backscattering measurements showed a much larger optical mean free path for the metal-infiltrated opals compared to the skin depth of the metals. Chapter 5 deals with the enhancement and inhibition of the spontaneous emission in PCs. In addition, the effect of the PBG on the photo-induced absorption (PA) of a π-conjugated polymer, when the absorption band lies within the PBG, is investigated for the first time. Changes in the PA spectrum of a π-conjugated polymer, DOO-PPP, infiltrated in opals were observed that are probably influenced by the photonic stop-band. This dissertation ends with some suggestions in Chapter 6 for future experiments.

Apparatus for growing crystals

NASA Technical Reports Server (NTRS)

Jasinski, Thomas J. (Inventor); Witt, August F. (Inventor)

1986-01-01

An improved apparatus and method for growing crystals from a melt employing a heat pipe, consisting of one or more sections, each section serving to control temperature and thermal gradients in the crystal as it forms inside the pipe.

Integrated molecular, biochemical, and physiological assessment unravels key extraction method mediated influences on rat neonatal cardiomyocytes.

PubMed

Jensen, Leonardo; Neri, Elida; Bassaneze, Vinicius; De Almeida Oliveira, Nathalia C; Dariolli, Rafael; Turaça, Lauro T; Levy, Débora; Veronez, Douglas; Ferraz, Mariana S A; Alencar, Adriano M; Bydlowski, Sérgio P; Cestari, Idágene A; Krieger, José Eduardo

2018-07-01

Neonatal cardiomyocytes are instrumental for disease modeling, but the effects of different cell extraction methods on basic cell biological processes remain poorly understood. We assessed the influence of two popular methods to extract rat neonatal cardiomyocytes, Pre-plating (PP), and Percoll (PC) on cell structure, metabolism, and function. Cardiomyocytes obtained from PP showed higher gene expression for troponins, titin, and potassium and sodium channels compared to PC. Also, PP cells displayed higher levels of troponin I protein. Cells obtained from PC displayed higher lactate dehydrogenase activity and lactate production than PP cells, indicating higher anaerobic metabolism after 8 days of culture. In contrast, reactive oxygen species levels were higher in PP cells as indicated by ethidium and hydroxyethidium production. Consistent with these data, protein nitration was higher in PP cells, as well as nitrite accumulation in cell medium. Moreover, PP cells showed higher global intracellular calcium under basal and 1 mM isoprenaline conditions. In a calcium-transient assessment under electrical stimulation (0.5 Hz), PP cells displayed higher calcium amplitude than cardiomyocytes obtained from PC and using a traction force microscope technique we observed that PP cardiomyocytes showed the highest relaxation. Collectively, we demonstrated that extraction methods influence parameters related to cell structure, metabolism, and function. Overall, PP derived cells are more active and mature than PC cells, displaying higher contractile function and generating more reactive oxygen species. On the other hand, PC derived cells display higher anaerobic metabolism, despite comparable high yields from both protocols. © 2017 Wiley Periodicals, Inc.

Recent Southeast Asian domestication and Lapita dispersal of sacred male pseudohermaphroditic “tuskers” and hairless pigs of Vanuatu

PubMed Central

Lum, J. Koji; McIntyre, James K.; Greger, Douglas L.; Huffman, Kirk W.; Vilar, Miguel G.

2006-01-01

Recent analyses of global pig populations revealed strict correlations between mtDNA phylogenies and geographic locations. An exception was the monophyletic “Pacific clade” (PC) of pigs not previously linked to any specific location. We examined mtDNA sequences of two varieties of Vanuatu sacred pigs, the male pseudohermaphroditic Narave from the island of Malo (n = 9) and the hairless Kapia from the island of Tanna (n = 9), as well as control pigs (n = 21) from the islands of Malo, Tanna, and Epi and compared them with GenBank sequences to determine (i) the distribution of PC and introduced domestic lineages within Vanuatu, (ii) relationship between the Narave and Kapia, and (iii) origin of the PC. All of the Narave share two PC mtDNA sequences, one of which matches the sequence of a Narave collected in 1927, consistent with an unbroken maternal descent of these intersex pigs from the original pigs brought to Vanuatu 3,200 years ago. One-third of the Kapia share a single PC lineage also found in the Narave. The remaining Kapia lineages are associated with recently introduced, globally distributed domestic breeds. The predominant Narave lineage is also shared with two wild boars from Vietnam. These data suggest that PC pigs were recently domesticated within Southeast Asia and dispersed during the human colonization of Remote Oceania associated with the Lapita cultural complex. More extensive sampling of Southeast Asian wild boar diversity may refine the location of Pacific pig domestication and potentially the proximate homeland of the Lapita cultural complex. PMID:17088556

Principal component and clustering analysis on molecular dynamics data of the ribosomal L11·23S subdomain.

PubMed

Wolf, Antje; Kirschner, Karl N

2013-02-01

With improvements in computer speed and algorithm efficiency, MD simulations are sampling larger amounts of molecular and biomolecular conformations. Being able to qualitatively and quantitatively sift these conformations into meaningful groups is a difficult and important task, especially when considering the structure-activity paradigm. Here we present a study that combines two popular techniques, principal component (PC) analysis and clustering, for revealing major conformational changes that occur in molecular dynamics (MD) simulations. Specifically, we explored how clustering different PC subspaces effects the resulting clusters versus clustering the complete trajectory data. As a case example, we used the trajectory data from an explicitly solvated simulation of a bacteria's L11·23S ribosomal subdomain, which is a target of thiopeptide antibiotics. Clustering was performed, using K-means and average-linkage algorithms, on data involving the first two to the first five PC subspace dimensions. For the average-linkage algorithm we found that data-point membership, cluster shape, and cluster size depended on the selected PC subspace data. In contrast, K-means provided very consistent results regardless of the selected subspace. Since we present results on a single model system, generalization concerning the clustering of different PC subspaces of other molecular systems is currently premature. However, our hope is that this study illustrates a) the complexities in selecting the appropriate clustering algorithm, b) the complexities in interpreting and validating their results, and c) by combining PC analysis with subsequent clustering valuable dynamic and conformational information can be obtained.

A person-centered integrated care quality framework, based on a qualitative study of patients' evaluation of care in light of chronic care ideals.

PubMed

Berntsen, Gro; Høyem, Audhild; Lettrem, Idar; Ruland, Cornelia; Rumpsfeld, Markus; Gammon, Deede

2018-06-20

Person-Centered Integrated Care (PC-IC) is believed to improve outcomes and experience for persons with multiple long-term and complex conditions. No broad consensus exists regarding how to capture the patient-experienced quality of PC-IC. Most PC-IC evaluation tools focus on care events or care in general. Building on others' and our previous work, we outlined a 4-stage goal-oriented PC-IC process ideal: 1) Personalized goal setting 2) Care planning aligned with goals 3) Care delivery according to plan, and 4) Evaluation of goal attainment. We aimed to explore, apply, refine and operationalize this quality of care framework. This paper is a qualitative evaluative review of the individual Patient Pathways (iPP) experiences of 19 strategically chosen persons with multimorbidity in light of ideals for chronic care. The iPP includes all care events, addressing the persons collected health issues, organized by time. We constructed iPPs based on the electronic health record (from general practice, nursing services, and hospital) with patient follow-up interviews. The application of the framework and its refinement were parallel processes. Both were based on analysis of salient themes in the empirical material in light of the PC-IC process ideal and progressively more informed applications of themes and questions. The informants consistently reviewed care quality by how care supported/ threatened their long-term goals. Personal goals were either implicit or identified by "What matters to you?" Informants expected care to address their long-term goals and placed responsibility for care quality and delivery at the system level. The PC-IC process framework exposed system failure in identifying long-term goals, provision of shared long-term multimorbidity care plans, monitoring of care delivery and goal evaluation. The PC-IC framework includes descriptions of ideal care, key questions and literature references for each stage of the PC-IC process. This first version of a PC-IC process framework needs further validation in other settings. Gaps in care that are invisible with event-based quality of care frameworks become apparent when evaluated by a long-term goal-driven PC-IC process framework. The framework appears meaningful to persons with multimorbidity.